Self-Reported Recovery from 2-Week 12-Hour Shift Work Schedules: A 14-Day Follow-Up.

PubMed

Merkus, Suzanne L; Holte, Kari Anne; Huysmans, Maaike A; van de Ven, Peter M; van Mechelen, Willem; van der Beek, Allard J

2015-09-01

Recovery from fatigue is important in maintaining night workers' health. This study compared the course of self-reported recovery after 2-week 12-hour schedules consisting of either night shifts or swing shifts (i.e., 7 night shifts followed by 7 day shifts) to such schedules consisting of only day work. Sixty-one male offshore employees-20 night workers, 16 swing shift workers, and 25 day workers-rated six questions on fatigue (sleep quality, feeling rested, physical and mental fatigue, and energy levels; scale 1-11) for 14 days after an offshore tour. After the two night-work schedules, differences on the 1(st) day (main effects) and differences during the follow-up (interaction effects) were compared to day work with generalized estimating equations analysis. After adjustment for confounders, significant main effects were found for sleep quality for night workers (1.41, 95% confidence interval 1.05-1.89) and swing shift workers (1.42, 95% confidence interval 1.03-1.94) when compared to day workers; their interaction terms were not statistically significant. For the remaining fatigue outcomes, no statistically significant main or interaction effects were found. After 2-week 12-hour night and swing shifts, only the course for sleep quality differed from that of day work. Sleep quality was poorer for night and swing shift workers on the 1(st) day off and remained poorer for the 14-day follow-up. This showed that while working at night had no effect on feeling rested, tiredness, and energy levels, it had a relatively long-lasting effect on sleep quality.

Healthy Diet And Reduction Of Chronic Disease Risks Of Night Shift Workers.

PubMed

Ferri, Giovanni M; Cavone, Domenica; Intranuovo, Graziana; Macinagrossa, Linda

2017-07-20

The large increase in epidemiological studies on night shift work is due to the important effects of night shift work on workers' health and psychophysical wellbeing. The short-term effects-insomnia, difficulties in managing work and private life, lower work performance, and more work and extra-work accidents-are easily studied. However, there are several long-term effects that are difficult to study because of the need for detailed exposure assessment and the long latency periods of these diseases. The aim was to collect epidemiologic evidence of diseases in night shift workers, describing their biological pathways and a set of dietary guidelines. This is a review on diet and health effects in night shift workers. Significant increases in the rate ratios and hazard ratios of different diseases were associated with modified eating behaviours and poor eating habits among night shift workers. Night shift work is a risk factor for disruption of the circadian rhythms and for some genetic deregulation because it produces the inversion of the sleep/wake cycle and modifies the alternation between activity and rest. A healthy diet and improved dietary practices, together with other factors, can reduce shift workers' chronic disease risk. The literature showed the importance of eating behaviour in order to prevent diseases in these workers; therefore, educational programmes are necessary to encourage several important lifestyle changes. The target of our future research will be the role of food components in some dietetic habits for the prevention of disease in night shift workers. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Actigraph measures of sleep among female hospital employees working day or alternating day and night shifts.

PubMed

Korsiak, Jill; Tranmer, Joan; Leung, Michael; Borghese, Michael M; Aronson, Kristan J

2017-07-14

Sleep disturbance is common among shift workers, and may be an important factor in the effect of shift work on chronic disease development. In this cross-sectional study, we described sleep patterns of 294 female hospital workers (142 alternating day-night shift workers, 152 day workers) and determined associations between shift work and sleep duration. Rest-activity cycles were recorded with the ActiGraph GT3X+ for 1 week. Analyses were stratified by chronotype of shift workers. Using all study days to calculate average sleep duration, shift workers slept approximately 13 min less than day workers during main sleep periods, while 24-h sleep duration did not differ between day workers and shift workers. Results from age-adjusted models demonstrated that all shift workers, regardless of chronotype, slept 20-30 min less than day workers on day shifts during main and total sleep. Early and intermediate chronotypes working night shifts slept between 114 and 125 min less than day workers, both with regard to the main sleep episode and 24-h sleep duration, while the difference was less pronounced among late chronotypes. When sleep duration on free days was compared between shift workers and day workers, only shift workers with late chronotypes slept less, by approximately 50 min, than day workers during main sleep. Results from this study demonstrate how an alternating day-night shift work schedule impacts sleep negatively among female hospital workers, and the importance of considering chronotype in sleep research among shift workers. © 2017 European Sleep Research Society.

Night shift work exposure profile and obesity: Baseline results from a Chinese night shift worker cohort.

PubMed

Sun, Miaomiao; Feng, Wenting; Wang, Feng; Zhang, Liuzhuo; Wu, Zijun; Li, Zhimin; Zhang, Bo; He, Yonghua; Xie, Shaohua; Li, Mengjie; Fok, Joan P C; Tse, Gary; Wong, Martin C S; Tang, Jin-Ling; Wong, Samuel Y S; Vlaanderen, Jelle; Evans, Greg; Vermeulen, Roel; Tse, Lap Ah

2018-01-01

This study aimed to evaluate the associations between types of night shift work and different indices of obesity using the baseline information from a prospective cohort study of night shift workers in China. A total of 3,871 workers from five companies were recruited from the baseline survey. A structured self-administered questionnaire was employed to collect the participants' demographic information, lifetime working history, and lifestyle habits. Participants were grouped into rotating, permanent and irregular night shift work groups. Anthropometric parameters were assessed by healthcare professionals. Multiple logistic regression models were used to evaluate the associations between night shift work and different indices of obesity. Night shift workers had increased risk of overweight and obesity, and odds ratios (ORs) were 1.17 (95% CI, 0.97-1.41) and 1.27 (95% CI, 0.74-2.18), respectively. Abdominal obesity had a significant but marginal association with night shift work (OR = 1.20, 95% CI, 1.01-1.43). A positive gradient between the number of years of night shift work and overweight or abdominal obesity was observed. Permanent night shift work showed the highest odds of being overweight (OR = 3.94, 95% CI, 1.40-11.03) and having increased abdominal obesity (OR = 3.34, 95% CI, 1.19-9.37). Irregular night shift work was also significantly associated with overweight (OR = 1.56, 95% CI, 1.13-2.14), but its association with abdominal obesity was borderline (OR = 1.26, 95% CI, 0.94-1.69). By contrast, the association between rotating night shift work and these parameters was not significant. Permanent and irregular night shift work were more likely to be associated with overweight or abdominal obesity than rotating night shift work. These associations need to be verified in prospective cohort studies.

Association between rotating night shift work and metabolic syndrome in Korean workers: differences between 8-hour and 12-hour rotating shift work.

PubMed

Oh, Jae-Il; Yim, Hyeon Woo

2018-02-07

This study aimed to analyze the association between the shift work schedule and metabolic syndrome (MetS). This is a retrospective longitudinal study based on the 2015 health checkup data of 2,090 workers evaluated for MetS in 2010 at a general hospital in Korea. The participants were divided according to their shift work schedule into daytime, three-shift (8-h rotation), and two-shift (12-h rotation) workers. The index that indicates the association between the shift work schedule and MetS is the odds ratio (OR) calculated using multivariate logistic regression. The analysis for the entire group of workers indicated that there was positive association between two-shift rotation and MetS (OR=1.58, 95% confidence interval [CI]: 1.09, 2.29). In the analysis of rotating night-shift workers, the years of rotating night shifts, frequency of night-shift work, and sleep disturbance were added to the confounding variables, and two-shift work remained positively associated with MetS (OR=1.72, 95% CI: 1.10, 2.70). The risk of MetS differs based on the shift work schedules they engage in. Hence, structural changes to the shift work schedules are required to prevent MetS in night-shift workers.

Association between rotating night shift work and metabolic syndrome in Korean workers: differences between 8-hour and 12-hour rotating shift work

PubMed Central

OH, Jae-Il; YIM, Hyeon Woo

2017-01-01

This study aimed to analyze the association between the shift work schedule and metabolic syndrome (MetS). This is a retrospective longitudinal study based on the 2015 health checkup data of 2,090 workers evaluated for MetS in 2010 at a general hospital in Korea. The participants were divided according to their shift work schedule into daytime, three-shift (8-h rotation), and two-shift (12-h rotation) workers. The index that indicates the association between the shift work schedule and MetS is the odds ratio (OR) calculated using multivariate logistic regression. The analysis for the entire group of workers indicated that there was positive association between two-shift rotation and MetS (OR=1.58, 95% confidence interval [CI]: 1.09, 2.29). In the analysis of rotating night-shift workers, the years of rotating night shifts, frequency of night-shift work, and sleep disturbance were added to the confounding variables, and two-shift work remained positively associated with MetS (OR=1.72, 95% CI: 1.10, 2.70). The risk of MetS differs based on the shift work schedules they engage in. Hence, structural changes to the shift work schedules are required to prevent MetS in night-shift workers. PMID:29046489

Self-Reported Recovery from 2-Week 12-Hour Shift Work Schedules: A 14-Day Follow-Up

PubMed Central

Merkus, Suzanne L.; Holte, Kari Anne; Huysmans, Maaike A.; van de Ven, Peter M.; van Mechelen, Willem; van der Beek, Allard J.

2015-01-01

Background Recovery from fatigue is important in maintaining night workers' health. This study compared the course of self-reported recovery after 2-week 12-hour schedules consisting of either night shifts or swing shifts (i.e., 7 night shifts followed by 7 day shifts) to such schedules consisting of only day work. Methods Sixty-one male offshore employees—20 night workers, 16 swing shift workers, and 25 day workers—rated six questions on fatigue (sleep quality, feeling rested, physical and mental fatigue, and energy levels; scale 1–11) for 14 days after an offshore tour. After the two night-work schedules, differences on the 1st day (main effects) and differences during the follow-up (interaction effects) were compared to day work with generalized estimating equations analysis. Results After adjustment for confounders, significant main effects were found for sleep quality for night workers (1.41, 95% confidence interval 1.05–1.89) and swing shift workers (1.42, 95% confidence interval 1.03–1.94) when compared to day workers; their interaction terms were not statistically significant. For the remaining fatigue outcomes, no statistically significant main or interaction effects were found. Conclusion After 2-week 12-hour night and swing shifts, only the course for sleep quality differed from that of day work. Sleep quality was poorer for night and swing shift workers on the 1st day off and remained poorer for the 14-day follow-up. This showed that while working at night had no effect on feeling rested, tiredness, and energy levels, it had a relatively long-lasting effect on sleep quality. PMID:26929834

Roles of safety climate and shift work on perceived injury risk: a multi-level analysis.

PubMed

Huang, Yueng-Hsiang; Chen, Jiu-Chiuan; DeArmond, Sarah; Cigularov, Konstantin; Chen, Peter Y

2007-11-01

This study evaluated the relationship between employees' work shift (i.e., day shift versus night shift) and perceptions of injury risk, and how the relationship is affected by company level safety climate and injury frequency. The results showed that night shift workers perceived a higher level of injury risk compared to day shift workers. Both company level safety climate and injury frequency played critical roles in predicting individual perceived work injury risk. Perception of injury risk of night shift workers was significantly lower when they perceived high-level rather than low-level safety climate. However, this pattern was not noticeable for day shift workers. These findings highlighted the importance of considering company level factors when attempting to understand the differences between day shift and night shift work on an individual's perception of injury risk.

Subjective alertness and sleep quality in connection with permanent 12-hour day and night shifts.

PubMed

Gillberg, M

1998-01-01

The aim of this study was to compare permanent 12-hour day and night shifts (shift change over times at 0500 and 1700) in a shift system with 3 work periods followed by 4 free days. Sleep diaries were collected after main periods of sleep, and sleepiness ratings [Karolinska sleepiness scale (KSS)] were obtained 4 times during the last free day and also during the following 3 workshifts. Eighteen to twenty night workers and 8-10 day workers (depending on the instrument) participated. The day workers were significantly sleepier during their workdays. Times for going to bed and for rising differed between the groups. The amount of sleep per week did not differ between groups, but the pattern across days did in that the day workers had a short sleep (5 hours) before the first day and 6 hours of sleep after the other two. Night workers slept long (9 hours) before the first shift and had 6.5-hour sleep periods after the other shifts. During free time the day workers slept around 9 hours and the night workers around 8 hours. Sleep quality and ease of awakening showed no group differences in overall levels, but the day workers had difficulties awakening before their shifts. The night workers had little variation in sleep quality or difficulties awakening. The suggested explanation for the greater sleepiness and difficulties awakening among the day workers was the early start of the shift and the difficulties the workers had with phase advancing their sleep-wake rhythm.

Heart rate variability in male shift workers in automobile manufacturing factories in South Korea.

PubMed

Lee, Sangyoon; Kim, Ho; Kim, Dae-Hwan; Yum, Myunggul; Son, Mia

2015-10-01

The aim of this study was to determine the effect of circadian rhythm disruption on cardiovascular autonomic regulation by examining potential differences in heart rate variability (HRV) between day- and night-shift workers. The study population consisted of 162 workers who worked both day and night shifts in two automobile manufacturing companies who underwent ambulatory 24-h electrocardiogram recording and completed questionnaires and sleep diaries. Both time and frequency domain indices of HRV were compared. HRV parameters (mean RR, SDNN, RMSSD, pNN50, TP, HF, LF, LF/HF ratio) reflecting sympathetic and parasympathetic modulation varied less with activity in night-shift workers. Circadian rhythm-mediated changes in autonomic regulation of the cardiovascular system were blunted in night-shift workers, which could contribute to an increased risk for cardiovascular disease in overnight workers.

Performance and sleepiness in nurses working 12-h day shifts or night shifts in a community hospital.

PubMed

Wilson, Marian; Permito, Regan; English, Ashley; Albritton, Sandra; Coogle, Carlana; Van Dongen, Hans P A

2017-10-05

Hospitals are around-the-clock operations and nurses are required to care for patients night and day. The nursing shortage and desire for a more balanced work-to-home life has popularized 12-h shifts for nurses. The present study investigated sleep/wake cycles and fatigue levels in 22 nurses working 12-h shifts, comparing day versus night shifts. Nurses (11day shift and 11 night shift) were recruited from a suburban acute-care medical center. Participants wore a wrist activity monitor and kept a diary to track their sleep/wake cycles for 2 weeks. They also completed a fatigue test battery, which included the Psychomotor Vigilance Test (PVT) and the Karolinska Sleepiness Scale (KSS), at the beginning, middle and end of 4 duty shifts. Daily sleep duration was 7.1h on average. No overall difference in mean daily sleep duration was found between nurses working day shifts versus night shifts. Objective performance on the PVT remained relatively good and stable at the start, middle, and end of duty shifts in day shift workers, but gradually degraded across duty time in night shift workers. Compared to day shift workers, night shift workers also exhibited more performance variability among measurement days and between participants at each testing time point. The same pattern was observed for subjective sleepiness on the KSS. However, congruence between objective and subjective measures of fatigue was poor. Our findings suggest a need for organizations to evaluate practices and policies to mitigate the inevitable fatigue that occurs during long night shifts, in order to improve patient and healthcare worker safety. Examination of alternative shift lengths or sanctioned workplace napping may be strategies to consider. Copyright © 2017 Elsevier Ltd. All rights reserved.

[The productivity of female shift workers].

PubMed

Vidacek, S; Radosević-Vidacek, B; Kaliterna, L; Prizmić, Z

1990-12-01

The productivity of female shift workers, working on a weekly rotating three-shift system, was examined. The afternoon shift was found to be the most productive and the night shift the least productive one. The greatest difference in productivity between shifts was found in the first two days of the week, when the productivity on night shift was significantly lower than that on the other two shifts. From the third day on there were no longer significant differences in productivity between shifts. The most productive and the least productive workers on night shift did not significantly differ in extraversion or in sleep duration after the night shift. Family responsibility was found to be associated with the duration of sleep after the night shift: married women slept significantly shorter after the night shift than unmarried women. However, this difference in sleep duration was not associated with productivity on night shift. Sleep duration after the afternoon shift (8 hours 40 minutes) was on average two hours longer than after the other two shifts. The difference in sleep duration after different shifts, along with circadian variations in alertness, readiness for work and performance efficiency, could be responsible for differences in productivity between shifts.

The effect of bright light on sleepiness among rapid-rotating 12-hour shift workers.

PubMed

Sadeghniiat-Haghighi, Khosro; Yazdi, Zohreh; Jahanihashemi, Hassan; Aminian, Omid

2011-01-01

About 20% of workers in industrialized countries are shift workers and more than half of them work on night or rotating shifts. Most night workers complain of sleepiness due to lack of adjustment of the circadian rhythm. In simulated night-work experiments, scheduled exposure to bright light has been shown to reduce these complaints. Our study assessed the effects of bright light exposure on sleepiness during night work in an industrial setting. In a cross-over design, 94 workers at a ceramic factory were exposed to either bright (2500 lux) or normal light (300 lux) during breaks on night shifts. We initiated 20-minute breaks between 24.00 and 02.00 hours. Sleepiness ratings were determined using the Stanford Sleepiness Scale at 22.00, 24.00, 02.00 and 04.00 hours. Under normal light conditions, sleepiness peaked at 02:00 hours. A significant reduction (22% compared to normal light conditions) in sleepiness was observed after workers were exposed to bright light. Exposure to bright light may be effective in reducing sleepiness among night workers.

Night shift work exposure profile and obesity: Baseline results from a Chinese night shift worker cohort

PubMed Central

Feng, Wenting; Wang, Feng; Zhang, Liuzhuo; Wu, Zijun; Li, Zhimin; Zhang, Bo; He, Yonghua; Xie, Shaohua; Li, Mengjie; Fok, Joan P. C.; Tse, Gary; Wong, Martin C. S.; Tang, Jin-ling; Wong, Samuel Y. S.; Vlaanderen, Jelle; Evans, Greg; Vermeulen, Roel; Tse, Lap Ah

2018-01-01

Aims This study aimed to evaluate the associations between types of night shift work and different indices of obesity using the baseline information from a prospective cohort study of night shift workers in China. Methods A total of 3,871 workers from five companies were recruited from the baseline survey. A structured self-administered questionnaire was employed to collect the participants’ demographic information, lifetime working history, and lifestyle habits. Participants were grouped into rotating, permanent and irregular night shift work groups. Anthropometric parameters were assessed by healthcare professionals. Multiple logistic regression models were used to evaluate the associations between night shift work and different indices of obesity. Results Night shift workers had increased risk of overweight and obesity, and odds ratios (ORs) were 1.17 (95% CI, 0.97–1.41) and 1.27 (95% CI, 0.74–2.18), respectively. Abdominal obesity had a significant but marginal association with night shift work (OR = 1.20, 95% CI, 1.01–1.43). A positive gradient between the number of years of night shift work and overweight or abdominal obesity was observed. Permanent night shift work showed the highest odds of being overweight (OR = 3.94, 95% CI, 1.40–11.03) and having increased abdominal obesity (OR = 3.34, 95% CI, 1.19–9.37). Irregular night shift work was also significantly associated with overweight (OR = 1.56, 95% CI, 1.13–2.14), but its association with abdominal obesity was borderline (OR = 1.26, 95% CI, 0.94–1.69). By contrast, the association between rotating night shift work and these parameters was not significant. Conclusion Permanent and irregular night shift work were more likely to be associated with overweight or abdominal obesity than rotating night shift work. These associations need to be verified in prospective cohort studies. PMID:29763461

[Night work and shift work - effects on the health of workers].

PubMed

Stryjewski, Piotr J; Kuczaj, Agnieszka; Domal-Kwiatkowska, Dorota; Mazurek, Urszula; Nowalany-Kozielska, Ewa

Number of shift workers increases in developed as well as in developing countries every year and equals 15- 20% of total amount of working people in Europe, 20% of total count of workers in United States of America, 6-32% in Asian countries and 8.1% workers in Poland. This type of employment is connected with such sectors of economy as medical care, industry, mining, transportation, communication and hospitality. The literature review analyses health effects of shift work and night work in the area of gastroenterology, circulatory system, oncologic diseases, neuropsychiatric and sleep disorders. In summary shift and night work have negative impact on human health. Further investigations analyzing impact of shift and night work are needed.

Self-reported health and sleep complaints among nursing personnel working under 12 h night and day shifts.

PubMed

Portela, Luciana F; Rotenberg, Lúcia; Waissmann, William

2004-01-01

This cross-sectional exploratory study involved health care workers of various skill types and levels. We tested the hypothesis that the prevalence of diseases, sleep complaints, and insufficient time for nonprofessional activities (family, leisure, and rest) are higher among night than day workers. Data collection was carried out in two public hospitals using questionnaires and other forms. Night work was explored as a risk factor, considering a night worker as one who had at least one night job on the occasion of the research. Data were assessed by a univariate analysis. The association between work schedule and the dependent variables--health conditions, sleep complaints, and insufficient time for nonprofessional activities--was evaluated through the estimation of the prevalence ratio, with a confidence interval of 95%. Two hundred and fifty-eight female nursing personnel participated; 41.5% were moonlighters, and only 20 worked a shift of less than 12h in length. Reports of migraine and need of medical care the 2 weeks before the survey were more prevalent among day than night workers (PR=0.71; CI=0.55-0.92 and PR=0.71; CI=0.52-0.95, respectively). Migraine headaches occurred less frequently among night than day workers as confirmed by comparing the reports of the night workers and day workers whose work history was always day shifts (PR = 0.74; CI = 0.57-0.96). Reports of mild emotional disorders (mild depression, tension, anxiety, or insomnia) were less frequent among night (PR=0.76; CI=0.59-0.98) and ex-night workers (PR=0.68; CI=0.50-0.91) than day workers who never had worked a night job. The healthy worker effect does not seem to explain the results of the comparisons between day and night workers. The possible role of exposure by day workers to some risk factors, such as stress, was suggested as an explanation for these results. No significant difference was observed between night and day workers as to sleep complaints, a result that may have been influenced by the nature of the shift-work schedule (no successive night shifts) and possibly nap taking during the night shift. Moreover, the long work hours and moonlighting of the healthcare workers, which is common in Brazil, may have masked other possible differences between the day and night workers. Among night workers, a significant relation was found between years working nights (more than 10 yrs) and high cholesterol values (PR = 2.58; CI = 1.07-6.27), a result that deserves additional study. Working nights more than four times per 2-week span was related to complaints about insufficient time for children (PR= 1.96; CI = 1.38-2.78) and rest/leisure (PR= 1.54; CI = 1.20-1.99). These results can be related to the "social value of time," as evenings and nights are when families usually spend time together. The complexity of the professional life and the consequent heterogeneity of the group of workers under shift-work schemes confound the results. More in-depth study of the questions raised here demands a more sophisticated epidemiological treatment and larger sample size.

Relationship between sleeping on the night shift and recovery from work among nursing workers - the influence of domestic work.

PubMed

Silva-Costa, Aline; Rotenberg, Lúcia; Griep, Rosane Harter; Fischer, Frida Marina

2011-05-01

This paper is a report of a study on the association between sleep patterns during work nights and recovery from work among nursing workers, considering domestic work hours. Several hospitals allow nursing workers to sleep during the night shift, but this is rarely evaluated from the workers' health perspective. The need for recovery from work concept can be useful for testing the impact of night work on sleep. Recovery is not a problem if workers have enough time to recover between periods of work. Therefore, domestic work would be likely to interfere in the recovery process. This cross-sectional study was carried out at three hospitals in 2005-2006, through a comprehensive questionnaire. All nursing teams engaged in assistance to patients were invited to participate. Analyses included female night workers with no incidence of insomnia. Participants (n = 396) were classified into those who did not sleep during night shifts, those who slept for up to 2 hours and those who slept for 2-3 hours. Binomial logistic regression analysis showed that sleeping on the job for 2-3 hours during night shifts is related to a better recovery from work provided the workers do not undergo long domestic work hours. Being allowed to sleep at work during night shifts seemed to contribute to, but was not enough to guarantee, a good recovery from work in the studied population. Recommendations to deal with sleep-deprivation among night workers should consider the complexity of gender roles on the recovery process. © 2011 Blackwell Publishing Ltd.

Do permanent night workers show circadian adjustment? A review based on the endogenous melatonin rhythm.

PubMed

Folkard, Simon

2008-04-01

"Permanent" or "fixed" night shifts have been argued to offer a potential benefit over rotating shift systems in that they may serve to maximize circadian adjustment and hence minimize the various health and safety problems associated with night work. For this reason, some authors have argued in favor of permanent shift systems, but their arguments assume at least a substantial, if not complete, adjustment of the circadian clock. They have emphasized the finding that the day sleeps taken between successive night shifts by permanent night workers are rather longer than those of either slowly or rapidly rotating shift workers, but this could simply reflect increased pressure for sleep. The present paper reviews the literature on the adjustment to permanent night work of the circadian rhythm in the secretion of melatonin, which is generally considered to be the best known indicator of the state of the endogenous circadian body clock. Studies of workers in "abnormal" environments, such as oil rigs and remote mining operations, were excluded, as the nature of these unique settings might serve to assist adjustment. The results of the six studies included indicate that only a very small minority (<3%) of permanent night workers evidence "complete"adjustment of their endogenous melatonin rhythm to night work, less than one in four permanent night workers evidence sufficiently "substantial" adjustment to derive any benefit from it, there is no difference between studies conducted in normal or dim lighting, and there is no evidence of gender difference in the adjustment to permanent night work. It is concluded that in normal environments, permanent night-shift systems are unlikely to result in sufficient circadian adjustment in most individuals to benefit health and safety.

Night Shift Work, Genetic Risk, and Type 2 Diabetes in the UK Biobank.

PubMed

Vetter, Céline; Dashti, Hassan S; Lane, Jacqueline M; Anderson, Simon G; Schernhammer, Eva S; Rutter, Martin K; Saxena, Richa; Scheer, Frank A J L

2018-04-01

To examine the effects of past and current night shift work and genetic type 2 diabetes vulnerability on type 2 diabetes odds. In the UK Biobank, we examined associations of current ( N = 272,214) and lifetime ( N = 70,480) night shift work exposure with type 2 diabetes risk (6,770 and 1,191 prevalent cases, respectively). For 180,704 and 44,141 unrelated participants of European ancestry (4,002 and 726 cases, respectively) with genetic data, we assessed whether shift work exposure modified the relationship between a genetic risk score (comprising 110 single-nucleotide polymorphisms) for type 2 diabetes and prevalent diabetes. Compared with day workers, all current night shift workers were at higher multivariable-adjusted odds for type 2 diabetes (none or rare night shifts: odds ratio [OR] 1.15 [95% CI 1.05-1.26]; some nights: OR 1.18 [95% CI 1.05-1.32]; and usual nights: OR 1.44 [95% CI 1.19-1.73]), except current permanent night shift workers (OR 1.09 [95% CI 0.93-1.27]). Considering a person's lifetime work schedule and compared with never shift workers, working more night shifts per month was associated with higher type 2 diabetes odds (<3/month: OR 1.24 [95% CI 0.90-1.68]; 3-8/month: OR 1.11 [95% CI 0.90-1.37]; and >8/month: OR 1.36 [95% CI 1.14-1.62]; P trend = 0.001). The association between genetic type 2 diabetes predisposition and type 2 diabetes odds was not modified by shift work exposure. Our findings show that night shift work, especially rotating shift work including night shifts, is associated with higher type 2 diabetes odds and that the number of night shifts worked per month appears most relevant for type 2 diabetes odds. Also, shift work exposure does not modify genetic risk for type 2 diabetes, a novel finding that warrants replication. © 2018 by the American Diabetes Association.

Cortisol, reaction time test and health among offshore shift workers.

PubMed

Harris, Anette; Waage, Siri; Ursin, Holger; Hansen, Ase Marie; Bjorvatn, Bjørn; Eriksen, Hege R

2010-10-01

The stress hormone cortisol shows a pronounced endogenous diurnal rhythm, which is affected by the sleep/wake cycle, meals and activity. Shift work and especially night work disrupts the sleep/wake cycle and causes a desynchronization of the natural biological rhythms. Therefore, different shift schedules may have different impact on performance at work and health. The purpose was to study if health, reaction time, and the cortisol rhythm were negatively affected when a group of shift workers changed their work schedule from ordinary day-night shift (fixed shift) to "swing shift". 19 healthy workers on a Norwegian oil rig participated in the study. They worked 2 weeks offshore followed by 4 weeks off work. The ordinary schedule consisted of 12-h day shift and 12-h night shift every other work period (14 days or nights=fixed shift). "Swing shift" involved 1 week of night shift, followed by 1 week of day shift during the work period. All participants worked ordinary day-night shift when baseline data were collected (questionnaires, saliva cortisol, and reaction time during work). After collection of baseline data the workers changed their work schedule to "swing shift", for every working period, and 9 months later the same data were collected. "Swing shift" did not give any negative health effects or any negative changes in reaction time during the day they shifted from night work to day work. Personnel adapted to night shift within a week regardless of schedule, but recovery from night shift took longer time. During swing shift the cortisol rhythm went back towards a normal rhythm in the second week, but it was not returned completely to normal values when they returned home for the 4 weeks off period. However, the cortisol rhythms were readapted to normal values after 1 week at home. For personnel returning home directly from 14 consecutive night shifts, cortisol adaptation was not complete after 1 week at home. We found no increase in health complaints from swing shift or reaction time in the shift from night to day work. Recovery from night shift takes longer time. Copyright © 2010 Elsevier Ltd. All rights reserved.

Sleep patterns among shift-working flight controllers of the International Space Station: an observational study on the JAXA Flight Control Team.

PubMed

Mizuno, Koh; Matsumoto, Akiko; Aiba, Tatsuya; Abe, Takashi; Ohshima, Hiroshi; Takahashi, Masaya; Inoue, Yuichi

2016-09-01

Flight controllers of the International Space Station (ISS) are engaged in shift work to provide 24-h coverage to support ISS systems. The purpose of this study was to investigate the prevalence and associated factors of shift work sleep disorder (SWSD) among Japanese ISS flight controllers. A questionnaire study was conducted using the Standard Shiftwork Index to evaluate sleep-related problems and possible associated variables. Among 52 respondents out of 73 flight controllers, 30 subjects were identified as night shift workers who worked 3 or more night shifts per month. Those night shift workers who answered "almost always" to questions about experiencing insomnia or excessive sleepiness in any case of work shifts and days off were classified as having SWSD. Additionally, 7 night shift workers participated in supplemental wrist actigraphy data collection for 7 to 8 days including 3 to 4 days of consecutive night shifts. Fourteen of 30 night shift workers were classified as having SWSD. Significant group differences were observed where the SWSD group felt that night shift work was harder and reported more frequent insomniac symptoms after a night shift. However, no other variables demonstrated remarkable differences between groups. Actigraphy results characterized 5 subjects reporting better perceived adaptation as having regular daytime sleep, for 6 to 9 h in total, between consecutive night shifts. On the other hand, 2 subjects reporting perceived maladaptation revealed different sleep patterns, with longer daytime sleep and large day-to-day variation in daytime sleep between consecutive night shifts, respectively. As the tasks for flight control require high levels of alertness and cognitive function, several characteristics, namely shift-working schedule (2 to 4 consecutive night shifts), very short break time (5 to 10 min/h) during work shifts, and cooperative work with onboard astronauts during the evening/night shift, accounted for increasing workloads especially in the case of night shifts, resulting in higher or equal prevalence of SWSD to that among other shift-working populations. Further studies are required to collect more actigraphy data and examine the possibility of interventions to improve SWSD.

Occupational health services for shift and night workers.

PubMed

Koller, M

1996-02-01

It is important for an occupational health service to plan health supervision and measures for shift and night workers considering the biorhythmic and psychosocial desynchronisation, as well as the frequent prevalence of combined effects of adverse environmental and working conditions. The measures taken should be preventive to reduce the expected health risks rather than being rehabilitative. Both a medical surveillance and a counselling service are recommended before and during engagement in shift and night work. Sleep, digestive, metabolic and cardiovascular troubles should be noted and followed up. Medical counselling is especially necessary in the first months of shift and night work exposure and then after long-term exposure. The postulate for timed surveillance and intervention is supported by data of our epidemiologic investigations. The importance of the single health measures is underlined by direct reference to the relevant literature. Recommendations that should be applied in all countries and enterprises are in accordance with the ILO Night Work Convention 1990a and include: (1) appropriate occupational health services provided for night and shift workers, including counselling; (2) first aid facilities during all shift hours; (3) the option of transfer to day work when certified unfit for night work for reasons of health; and (4) measures for women on night shifts, in particular special maternity protection (transfer to day work, social security benefits or an extension of maternity leave). Examples of occupational health services already installed in some states for shift and night workers, and information on future developments are given. Up to now the medical service has been implemented mostly on the basis of collective agreements rather than on the basis of legal provisions. The Austrian Night Shift/Heavy Work Law Regulations of 1981, revised 1993, are cited: workers exposed to night shifts under defined single or combined additional heavy workloads are entitled to a special health assessment, additional rest pauses, additional free time and early retirement depending on years of exposure.

Insomnia in shift work.

PubMed

Vallières, Annie; Azaiez, Aïda; Moreau, Vincent; LeBlanc, Mélanie; Morin, Charles M

2014-12-01

Shift work disorder involves insomnia and/or excessive sleepiness associated with the work schedule. The present study examined the impact of insomnia on the perceived physical and psychological health of adults working on night and rotating shift schedules compared to day workers. A total of 418 adults (51% women, mean age 41.4 years), including 51 night workers, 158 rotating shift workers, and 209 day workers were selected from an epidemiological study. An algorithm was used to classify each participant of the two groups (working night or rotating shifts) according to the presence or absence of insomnia symptoms. Each of these individuals was paired with a day worker according to gender, age, and income. Participants completed several questionnaires measuring sleep, health, and psychological variables. Night and rotating shift workers with insomnia presented a sleep profile similar to that of day workers with insomnia. Sleep time was more strongly related to insomnia than to shift work per se. Participants with insomnia in the three groups complained of anxiety, depression, and fatigue, and reported consuming equal amounts of sleep-aid medication. Insomnia also contributed to chronic pain and otorhinolaryngology problems, especially among rotating shift workers. Work productivity and absenteeism were more strongly related to insomnia. The present study highlights insomnia as an important component of the sleep difficulties experienced by shift workers. Insomnia may exacerbate certain physical and mental health problems of shift workers, and impair their quality of life. Copyright © 2014 Elsevier B.V. All rights reserved.

Night shift and rotating shift in association with sleep problems, burnout and minor mental disorder in male and female employees.

PubMed

Cheng, Wan-Ju; Cheng, Yawen

2017-07-01

Shift work is associated with adverse physical and psychological health outcomes. However, the independent health effects of night work and rotating shift on workers' sleep and mental health risks and the potential gender differences have not been fully evaluated. We used data from a nationwide survey of representative employees of Taiwan in 2013, consisting of 16 440 employees. Participants reported their work shift patterns 1 week prior to the survey, which were classified into the four following shift types: fixed day, rotating day, fixed night and rotating night shifts. Also obtained were self-reported sleep duration, presence of insomnia, burnout and mental disorder assessed by the Brief Symptom Rating Scale. Among all shift types, workers with fixed night shifts were found to have the shortest duration of sleep, highest level of burnout score, and highest prevalence of insomnia and minor mental disorders. Gender-stratified regression analyses with adjustment of age, education and psychosocial work conditions showed that both in male and female workers, fixed night shifts were associated with greater risks for short sleep duration (<7 hours per day) and insomnia. In female workers, fixed night shifts were also associated with increased risks for burnout and mental disorders, but after adjusting for insomnia, the associations between fixed night shifts and poor mental health were no longer significant. The findings of this study suggested that a fixed night shift was associated with greater risks for sleep and mental health problems, and the associations might be mediated by sleep disturbance. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Circadian variation of melatonin, light exposure, and diurnal preference in day and night shift workers of both sexes.

PubMed

Papantoniou, Kyriaki; Pozo, Oscar J; Espinosa, Ana; Marcos, Josep; Castaño-Vinyals, Gemma; Basagaña, Xavier; Ribas, Ferran Calduch; Mirabent, Joan; Martín, Jordi; Carenys, Gemma; Martín, Celia Reyes; Middleton, Benita; Skene, Debra J; Kogevinas, Manolis

2014-07-01

Light-at-night has been shown in experimental studies to disrupt melatonin production but this has only partly been confirmed in studies of night shift workers. In this cross-sectional study, we examined the circadian variation of melatonin in relation to shift status, individual levels of light-at-night exposure, and diurnal preference, an attribute reflecting personal preference for activity in the morning or evening. One hundred and seventeen workers (75 night and 42 day) of both sexes, ages 22 to 64 years, were recruited from four companies. Participants collected urine samples from all voids over 24 hours and wore a data logger continuously recording their light exposure. Sociodemographic, occupational, lifestyle, and diurnal preference information were collected by interview. Concentrations of urinary 6-sulfatoxymelatonin (aMT6s), the main melatonin metabolite, were measured. Mean aMT6s levels were lower in night [10.9 ng/mg creatinine/hour; 95% confidence interval (CI), 9.5-12.6] compared with day workers (15.4; 95% CI, 12.3-19.3). The lowest aMT6s levels were observed in night workers with morning preference (6.4; 95% CI, 3.0-13.6). Peak time of aMT6s production occurred 3 hours later in night (08:42 hour, 95% CI, 07:48-09:42) compared with day workers (05:36 hour, 95% CI, 05:06-06:12). Phase delay was stronger among subjects with higher light-at-night exposure and number of nights worked. Night shift workers had lower levels and a delay in peak time of aMT6s production over a 24-hour period. Differences were modified by diurnal preference and intensity of light-at-night exposure. Night shift work affects levels and timing of melatonin production and both parameters may relate to future cancer risk. ©2014 American Association for Cancer Research.

Sleep quality in nurses: a randomized clinical trial of day and night shift workers.

PubMed

Niu, Shu-Fen; Chu, Hsin; Chung, Min-Huey; Lin, Chun-Chieh; Chang, Yu-Shiun; Chou, Kuei-Ru

2013-07-01

The study investigated the number of days off nurses working night shifts need to recover their sleep quality to the level of daytime workers during their days off. This study included 30 day-shift nurses and 32 night-shift nurses. It was conducted as a randomized clinical trial in the medical and surgical wards of a medical center in northern Taiwan in May and June 2010 using sleep diaries and sleep parameters collected by actigraphy on different workdays and days off. On workdays, the night-shift group had significantly less total sleep time (TST) on Day 5 and significantly lower sleep efficiency (SE) on Day 3 than the day-shift group. TSTs of the two groups on days off were higher than those on workdays. On the 4th consecutive day off, higher TST, a decrease in WASO, and an increase in SE suggests that the night-shift group had recovered their sleep quality to the level of the day-shift group on their days off. The SE of the night-shift group exceeded that of the day-shift group after the 4th consecutive day off, though the difference was not statistically significant in the present study. Based on these data, it is recommended that night-shift workers arrange a period of at least 4 days off after 5 consecutive night shifts and at least 5 days off if the staff who have previously worked night shifts are being assigned a set of different shifts.

Night work and BMI: is it related to on-shift napping?

PubMed

Silva-Costa, Aline; Griep, Rosane Härter; Rotenberg, Lúcia

2017-11-17

On-shift napping can benefit night workers regarding sleep loss, synchronization of circadian rhythms, and alertness. However, few studies on napping can be found in the literature focused on possible health benefits. This cross-sectional study has investigated the role of on-shift napping on the association between night work and BMI in 409 night-shift nursing professionals. The number of working nights and the years of exposure to night work were significantly associated with increased BMI levels among non-nappers, but not among nappers. Results suggest a benefit of napping for weight gain, thus subsidizing occupational health policies on the regulation of on-shift napping among nursing workers.

Night work and BMI: is it related to on-shift napping?

PubMed Central

Silva-Costa, Aline; Griep, Rosane Härter; Rotenberg, Lúcia

2017-01-01

ABSTRACT On-shift napping can benefit night workers regarding sleep loss, synchronization of circadian rhythms, and alertness. However, few studies on napping can be found in the literature focused on possible health benefits. This cross-sectional study has investigated the role of on-shift napping on the association between night work and BMI in 409 night-shift nursing professionals. The number of working nights and the years of exposure to night work were significantly associated with increased BMI levels among non-nappers, but not among nappers. Results suggest a benefit of napping for weight gain, thus subsidizing occupational health policies on the regulation of on-shift napping among nursing workers. PMID:29166450

Associations of rotational shift work and night shift status with hypertension: a systematic review and meta-analysis.

PubMed

Manohar, Sandhya; Thongprayoon, Charat; Cheungpasitporn, Wisit; Mao, Michael A; Herrmann, Sandra M

2017-10-01

The reported risks of hypertension (HTN) in rotating shift and night shift workers are controversial. The objective of this meta-analysis was to assess the association between shift work status and HTN. A literature search was performed using MEDLINE, EMBASE and Cochrane Database from inception through October 2016. Studies that reported odds ratios (OR) comparing the risk of HTN in shift workers were included. A prespecified subgroup analysis by rotating shift and night shift statuses were also performed. Pooled OR and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method. The protocol for this study is registered with International Prospective Register of Systematic Reviews; no. CRD42016051843. Twenty-seven observational studies (nine cohort and 18 cross-sectional studies) with a total of 394 793 individuals were enrolled. The pooled ORs of HTN in shift workers in cohort and cross-sectional studies were 1.31 (95% CI, 1.07-1.60) and 1.10 (95% CI, 1.00-1.20), respectively. When meta-analysis was restricted only to cohort studies in rotating shift, the pooled OR of HTN in rotating shift workers was 1.34 (95% CI, 1.08-1.67). The data regarding night shift and HTN in cohort studies was limited. The pooled OR of HTN in night shift workers in cross-sectional studies was 1.07 (95% CI, 0.85-1.35). Based on the findings of our meta-analysis, shiftwork status may play an important role in HTN, as there is a significant association between rotating shift work and HTN. However, there is no significant association between night shift status and risk of HTN.

Work schedule and self-reported hypertension - the potential beneficial role of on-shift naps for night workers.

PubMed

Rotenberg, Lúcia; Silva-Costa, Aline; Vasconcellos-Silva, Paulo Roberto; Griep, Rosane Härter

2016-01-01

Data on the association between shift work and hypertension are controversial. Sleep restriction is hypothesized to be involved in this relationship. Since on-shift nap can partly compensate for sleep deprivation among night workers, this investigation is aimed at (i) comparing the prevalence of hypertension among workers considering both current and former night work, (ii) testing the association between on-shift naps and hypertension among night workers, and (iii) analyzing the influence of sleep complaints in the association between on-shift nap and hypertension. Nap was defined as a sleep episode with duration shorter than the average nighttime sleep. A cross-sectional study was performed at the 18 largest public hospitals in Rio de Janeiro, Brazil, in 2010-2011 (N = 2588 female registered nurses). Nurses were informally allowed to nap for up to three consecutive hours during working nights. Workers completed a multidimensional questionnaire including self-reported information on physician diagnosis of hypertension, napping, and sleep complaints (insomnia, diurnal sleepiness, and non-satisfactory sleep). Epidemiological and statistical treatment of data included binomial logistic regression and interaction tests. Higher chances of hypertension were observed for both current and former night workers compared with workers with no previous experience in night work, i.e. exclusive day workers (OR = 1.68; CI95% 1.22-2.33 and OR = 1.40; CI95% 1.01-1.96, respectively) after adjustment for age, race/ethnicity, physical activity, smoking, alcohol consumption, insomnia, weekly work hours, and BMI. Compared with exclusive day workers, both non-nappers and nappers were at a higher likelihood of reporting hypertension (OR = 1.93 CI95% 1.35-2.79 and OR = 1.41 CI95% 1.08-2.20, respectively). An interaction was observed between napping behavior and insomnia (p = 0.037). In the whole sample of night workers, the lower OR for nappers was confirmed when they were directly compared with non-nappers (OR = 0.76 CI95% 0.59-0.98). Analysis of night workers stratified by insomnia showed a significant reduction in OR for nappers (compared to non-nappers) only among insomniacs (OR = 0.58). Napping during night work may be a protective factor for hypertension, particularly among insomniacs. Factors related to melatonin secretion, blood pressure control, and blood pressure dipping patterns are likely to be involved in the relationship between on-shift napping and blood pressure.

Klokwerk + study protocol: An observational study to the effects of night-shift work on body weight and infection susceptibility and the mechanisms underlying these health effects.

PubMed

Loef, Bette; van Baarle, Debbie; van der Beek, Allard J; van Kerkhof, Linda W; van de Langenberg, Daniëlla; Proper, Karin I

2016-08-02

Night-shift work may cause severe disturbances in the worker's circadian rhythm, which has been associated with the onset of health problems and diseases. As a substantial part of the workforce is exposed to night-shift work, harmful aspects of night-shift work should not be overlooked. The aim of the Klokwerk + study is to study the effects of night-shift work on body weight and infection susceptibility and the mechanisms underlying these health effects. First, we will study the relation between night-shift work exposure and body weight and between night-shift work exposure and infection susceptibility. Second, we will examine the mechanisms linking night-shift work exposure to body weight and infection susceptibility, with a specific focus on sleep, physical activity, diet, light exposure, vitamin D level, and immunological factors. Lastly, we will focus on the identification of biomarkers for chronic circadian disturbance associated with night-shift work. The design of this study is a prospective observational cohort study consisting of 1,960 health care workers aged 18-65 years. The study population will consist of a group of night-shift workers and an equally sized group of non-night-shift workers. During the study, there will be two measurement periods. As one of the main outcomes of this study is infection susceptibility, the measurement periods will take place at approximately the first (September/October) (T0) and the last month (April/May) (T1, after 6 months) of the flu season. The measurements will consist of questionnaires, anthropometric measurements, a smartphone application to determine infection susceptibility, food diaries, actigraphy, light sensors, and blood sample analyses. The Klokwerk + study will contribute to the current need for high-quality data on the health effects of night-shift work and its underlying behavioral and physiological mechanisms. The findings can be the starting point for the development of interventions that prevent negative health effects caused by night-shift work. In addition, the identification of biomarkers indicative of loss of homeostasis due to circadian disturbance may be an important asset in monitoring the effects of such interventions.

Influence of night-shift and napping at work on urinary melatonin, 17-β-estradiol and clock gene expression in pre-menopausal nurses.

PubMed

Bracci, M; Copertaro, A; Manzella, N; Staffolani, S; Strafella, E; Nocchi, L; Barbaresi, M; Copertaro, B; Rapisarda, V; Valentino, M; Santarelli, L

2013-01-01

Night-workers experience disruption of the sleep-wake cycle and light at night which may increase breast cancer risk by suppressing the nocturnal melatonin surge, resulting in higher levels of circulating estrogens. Night-work may also deregulate peripheral clock genes which have been found to be altered in breast cancer. This study investigated urinary 6-sulfatoxymelatonin (aMT6s), serum 17-beta-estradiol levels in premenopausal shift nurses at the end of the night-shift compared to a control group of daytime nurses. Peripheral clock gene expression in lymphocytes were also investigated. All participants were sampled in the follicular phase of the menstrual cycle. The effect of nurses’ ability to take a short nap during the night-shift was also explored. The shift-work group had significantly lower aMT6s levels than daytime nurses independently of a nap. Night-shift napping significantly influences 17-beta-estradiol levels resulting in higher outcomes in nurses who do not take a nap compared to napping group and daytime workers. Peripheral clock genes expression investigated was not significantly different among the groups. Our findings suggest that shift nurses experience changes in aMT6s levels after a night-shift. Napping habits influence 17-beta-estradiol levels at the end of a night-shift. These findings might be related to the increased cancer risk reported in night-shift workers and suggest that a short nap during night-shifts may exert a positive effect.

Shift work, safety, and aging.

PubMed

Folkard, Simon

2008-04-01

It has long been recognized that older shift workers may have shorter and more disturbed day sleeps between successive night shifts than their younger colleagues. This has given rise to considerable concern over the safety of aging shift workers because of the increasing age of the work force and increases in retirement age. Because there have been no direct studies of the combined effects of shift work and age on safety, the present paper begins by reviewing the literature relating safety to features of shift systems. It then considers the general effect of age on occupational injury rates before examining existing evidence of the combined effects of shift work and age on performance capabilities. The results of the literature review indicate that when the a priori risk is constant, there is reasonably clear evidence that injury rates are higher at night, and that they increase over successive night shifts more rapidly than over successive day shifts. Further, although occupational injuries are less frequent in older workers, those that do occur tend to be more serious. Finally, there is some suggestive evidence from studies of objectively measured performance capabilities that older workers may be less able to both maintain their performance over the course of a night shift and cope with longer spans of successive night shifts. It is concluded that it seems possible, even though unproven as yet, that older workers may be at greater risk both to injury and accident on the night shift. There is a strong need for future epidemiological studies of the combined effects of shift work and age on injuries and accidents, and that these should attempt to separate the effects of age per se from those of generation.

Effects of shift changes on female workers at a dish factory.

PubMed

Hirose, T; Tada, Y; Hasegawa, M

2001-12-01

This study investigated the effects of working night shifts on social and family life by examining changes in workers' daily life before and after a change in their shifts. Subjects were 40 women aged 27-59 years, working at a dish factory. During the health examination of night workers in autumn of 2000, the subjects were directly interviewed about changes in their lives induced by the shift change. Question parameters consisted of 8 items including 30 sub-items related to social and family life, such as sleep, rest, meals, sports, family time, hobbies, neighborhood association and social activities. The subjects selected one of four response categories: "becoming worse", "no change", "becoming better" and "difficult to determine." With regard to the percentage of "becoming worse", meal-related items ranked high in all of the shift types. "Family time" and "hobbies" showed high percentages in the subjects transferring from day shifts to night shifts, and in those transferring from early-morning shifts to night shifts. "Rest", "sports" and "hobbies" showed high percentages in the subjects transferring from night shifts to midnight shifts. Decreased sleeping hours were confirmed in all of the shift types, while the subjects tended to sleep more soundly. As the workers transfer to shifts at earlier hours, they were obliged to make sacrifices in various aspects of their social and family life. Therefore, much assistance in this regard should be given to them.

Night shift work at specific age ranges and chronic disease risk factors

PubMed Central

Ramin, Cody; Devore, Elizabeth E; Wang, Weike; Pierre-Paul, Jeffrey; Wegrzyn, Lani R; Schernhammer, Eva S

2014-01-01

Objectives We examined the association of night shift work history and age when night shift work was performed with cancer and cardiovascular disease risk factors among 54 724 women in the Nurses' Health Study (NHS) II. Methods We calculated age-adjusted and socioeconomic status-adjusted means and percentages for cancer and cardiovascular risk factors in 2009 across categories of night shift work history. We used multivariable-adjusted logistic regression to estimate odds ratios (ORs) and 95% CIs for key risk factors among 54 724 participants (72% ever shift workers). We further examined these associations by age (20–25, 26–35, 36– 45 and 46+ years) at which shift work was performed. Results Ever night shift workers had increased odds of obesity (body mass index ≥30 kg/m2; OR=1.37, 95% CI 1.31 to 1.43); higher caffeine intake (≥131 mg/day; OR=1.16, 95% CI 1.12 to 1.22) and total calorie intake (≥1715 kcal/day; OR=1.09, 95% CI 1.04 to 1.13); current smoking (OR=1.30, 95% CI 1.19 to 1.42); and shorter sleep durations (≤7 h of sleep/day; OR=1.19, 95% CI 1.15 to 1.24) compared to never night shift workers. These estimates varied depending on age at which night work was performed, with a suggestion that night shift work before age 25 was associated with fewer risk factors compared to night shift work at older ages. Conclusions Our results indicate that night shift work may contribute to an adverse chronic disease risk profile, and that risk factors may vary depending on the age at which night shift work was performed. PMID:25261528

Sleep and autonomic nervous system changes - enhanced cardiac sympathetic modulations during sleep in permanent night shift nurses.

PubMed

Chung, Min-Huey; Kuo, Terry B J; Hsu, Nanly; Chu, Hsin; Chou, Kuei-Ru; Yang, Cheryl C H

2009-05-01

Disturbed sleep is the most common problem among the many health-related effects of shift work, with shift workers clearly having higher rates of cardiac disorders. However, the possible mechanism underlying the related health effects of shift work has yet to be examined. Consequently, this study aimed to explore the influence of long-term night shift work on the sleep patterns of nurses and their cardiac autonomic nervous system during sleep. Our sample comprised ten permanent night shift and ten regular morning shift nurses. Nurses slept in their dormitory where they were allowed to sleep and wake spontaneously. All sleep parameters were digitized using an ambulatory polysomnographic recorder. Using sleep patterns and heart rate variability, the day- and nighttime sleep of permanent night shift nurses were compared with the nighttime sleep of regular morning shift nurses. Compared with the nighttime sleep of regular morning shift nurses, the pattern of daytime sleep of permanent night shift nurses showed significantly lower sleep onset latency. Permanent night shift nurses' daytime sleep also had greater proportions of Stage 3 and 4 (deep sleep), and arousal index than recorded during their nighttime sleep. Both the low frequency and low to high frequency ratio of the nighttime sleep of night shift nurses were significantly higher during periods of non-rapid eye movement (NREM) sleep than the nighttime sleep of morning shift workers. In addition, the electroencephalography delta-power of the nighttime sleep of night shift nurses was significantly lower during the first NREM episode sleep than those of both the daytime sleep of night shift workers and the nighttime sleep of morning shift nurses. Permanent night shift nurses have higher sympathetic activity during nighttime sleep than regular morning shift nurses. Night shift working may have effects on the sleeping patterns of nurses in the long run, inducing higher cardiac sympathetic regulation.

Absence from work in relation to length and distribution of shift hours

PubMed Central

Walker, J.; Mare, Gwynneth de la

1971-01-01

Walker, J., and de la Mare, Gwynneth (1971). Brit. J. industr. Med., 28, 36-44. Absence from work in relation to length and distribution of shift hours. A long period on night shift or even permanent night work has sometimes been suggested for those on continuous shift work to allow circadian rhythms to adapt. As the weekly hours of work have been reduced there is some evidence that a permanent night shift is practical, and about 12% of all shift workers are on this type of work. However, the case for permanent night shift must be established on grounds of both effectiveness and acceptability. The present study compares the absence experience, including sickness absence, of permanent day workers and permanent night workers matched for age and job in three undertakings which contained a range of working conditions. The question of the relationship between absence from work and total hours worked including overtime has been reopened, and in comparing absence from work according to the type of shift the total hours worked must also be taken into account. The relationship between the average hours when a man was at work and the amount of absence was tested. The men in the three undertakings worked a wide range of voluntary overtime. The results showed that in two undertakings long-term absence, mainly sickness absence, was higher on the night shift than on the day shift; and, in the third, absence was about the same on the two shifts. As the work load was less in the two undertakings with a higher absence on the night shift it was suggested that selective factors were operating. These results may be contrasted to studies which have compared the absence of rotating shift workers and day workers. In all three undertakings there was a tendency for absence to be less among high overtime workers than among those who worked medium or small amounts of overtime, although the trends were not consistent. There was no evidence at all that high overtime and absence from work were positively associated. The implications of these results are discussed. PMID:5101167

Association of salivary cortisol with chronomics of 24 hours ambulatory blood pressure/heart rate among night shift workers.

PubMed

Anjum, B; Verma, N S; Tiwari, S; Singh, R; Mahdi, A A; Singh, R B; Singh, R K

2011-08-01

Recent studies indicate a circadian rhythm in blood pressure and heart rate and its association with various neurotransmitters. In the present study, we examine the circadian nature of blood pressure/heart rate and salivary cortisol in night shift workers and whether these circadian changes produced by night shifts are reversible. Sixteen healthy nurses of both genders, aged 20-40 years, performing day and night shift duties, were randomly selected out of 22 who volunteered for this study. Ambulatory blood pressure monitoring was done in all the subjects and salivary cortisol levels were analyzed during both day and night shift duties. There were clinically significant changes in the Acrophase of blood pressure and cortisol levels, indicating ecphasia (odd timing of systolic blood pressure) individually during night as well as day shifts. However, this pattern was statistically not significant. A reverse pattern of Acrophase was observed in 8 out of 16 subjects when they were posted on day shift. No significant change was found in midline estimating statistics of rhythm (MESOR) of blood pressure values. Changes in Double amplitude (Predictable change) were observed in 8 subjects during night shifts as well as in 7 subjects during day shifts. However, the pattern was not similar and night workers had an altered circadian pattern in the night as well as during day shifts. Changes in Double amplitude, Acrophase and Salivary cortisol were found during night as well as day shifts but these changes were not statistically significant (p > 0.05) due to incomplete recovery during day shifts (changes again seen when they came back to day shifts). Salivary cortisol levels were lowest in early morning, increased at midnight and further increased in the afternoon during night shifts along with ecphasia. It is possible that nurses working the night shift felt more tired due to the altered circadian cycle.

Circadian Rhythm of Wrist Temperature among Shift Workers in South Korea: A Prospective Observational Study

PubMed Central

Kim, Hyunjoo; Kang, Suk-Hoon; Choo, Sang-Hyo; Lee, In-Seok; Choi, Kyung-Hwa

2017-01-01

Background: Human body temperature varies with circadian rhythm. To determine the effect of shift work on the circadian rhythm of the distal-skin temperature, wrist temperatures were measured. Methods: Wrist-skin temperatures were measured by an iButton® Temperature Logger. It was measured every 3 min for two and eight consecutive working days in the day and shift workers, respectively. Mesor, amplitude, and acrophase were measured by Cosinor analysis. Results: The shift-worker amplitude dropped significantly as the night shift progressed (0.92 to 0.85 °C), dropped further during rest (0.69 °C), and rose during the morning-shift days (0.82 °C). Day workers still had higher amplitudes (0.93 °C) than the morning-shift workers. The acrophase was delayed during the four night-shift days, then advanced during rest days and the morning-shift days. Nevertheless, the morning-shift worker acrophase was still significantly delayed compared to the day workers (08:03 a.m. vs. 04:11 a.m.). Conclusions: The further reduction of wrist-temperature amplitude during rest after the night shift may be due to the signal circadian rhythm disruption. Reduced amplitudes have been reported to be associated with intolerance to shift work. The findings of our study may help to design the most desirable schedule for shift workers. PMID:28946653

Circadian Rhythm of Wrist Temperature among Shift Workers in South Korea: A Prospective Observational Study.

PubMed

Jang, Tae-Won; Kim, Hyunjoo; Kang, Suk-Hoon; Choo, Sang-Hyo; Lee, In-Seok; Choi, Kyung-Hwa

2017-09-24

Background : Human body temperature varies with circadian rhythm. To determine the effect of shift work on the circadian rhythm of the distal-skin temperature, wrist temperatures were measured. Methods : Wrist-skin temperatures were measured by an iButton ® Temperature Logger. It was measured every 3 min for two and eight consecutive working days in the day and shift workers, respectively. Mesor, amplitude, and acrophase were measured by Cosinor analysis. Results : The shift-worker amplitude dropped significantly as the night shift progressed (0.92 to 0.85 °C), dropped further during rest (0.69 °C), and rose during the morning-shift days (0.82 °C). Day workers still had higher amplitudes (0.93 °C) than the morning-shift workers. The acrophase was delayed during the four night-shift days, then advanced during rest days and the morning-shift days. Nevertheless, the morning-shift worker acrophase was still significantly delayed compared to the day workers (08:03 a.m. vs. 04:11 a.m.). Conclusions : The further reduction of wrist-temperature amplitude during rest after the night shift may be due to the signal circadian rhythm disruption. Reduced amplitudes have been reported to be associated with intolerance to shift work. The findings of our study may help to design the most desirable schedule for shift workers.

Oxidative DNA damage during night shift work.

PubMed

Bhatti, Parveen; Mirick, Dana K; Randolph, Timothy W; Gong, Jicheng; Buchanan, Diana Taibi; Zhang, Junfeng Jim; Davis, Scott

2017-09-01

We previously reported that compared with night sleep, day sleep among shift workers was associated with reduced urinary excretion of 8-hydroxydeoxyguanosine (8-OH-dG), potentially reflecting a reduced ability to repair 8-OH-dG lesions in DNA. We identified the absence of melatonin during day sleep as the likely causative factor. We now investigate whether night work is also associated with reduced urinary excretion of 8-OH-dG. For this cross-sectional study, 50 shift workers with the largest negative differences in night work versus night sleep circulating melatonin levels (measured as 6-sulfatoxymelatonin in urine) were selected from among the 223 shift workers included in our previous study. 8-OH-dG concentrations were measured in stored urine samples using high performance liquid chromatography with electrochemical detection. Mixed effects models were used to compare night work versus night sleep 8-OH-dG levels. Circulating melatonin levels during night work (mean=17.1 ng/mg creatinine/mg creatinine) were much lower than during night sleep (mean=51.7 ng/mg creatinine). In adjusted analyses, average urinary 8-OH-dG levels during the night work period were only 20% of those observed during the night sleep period (95% CI 10% to 30%; p<0.001). This study suggests that night work, relative to night sleep, is associated with reduced repair of 8-OH-dG lesions in DNA and that the effect is likely driven by melatonin suppression occurring during night work relative to night sleep. If confirmed, future studies should evaluate melatonin supplementation as a means to restore oxidative DNA damage repair capacity among shift workers. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Impacts of shift work on sleep and circadian rhythms.

PubMed

Boivin, D B; Boudreau, P

2014-10-01

Shift work comprises work schedules that extend beyond the typical "nine-to-five" workday, wherein schedules often comprise early work start, compressed work weeks with 12-hour shifts, and night work. According to recent American and European surveys, between 15 and 30% of adult workers are engaged in some type of shift work, with 19% of the European population reportedly working at least 2 hours between 22:00 and 05:00. The 2005 International Classification of Sleep Disorders estimates that a shift work sleep disorder can be found in 2-5% of workers. This disorder is characterized by excessive sleepiness and/or sleep disruption for at least one month in relation with the atypical work schedule. Individual tolerance to shift work remains a complex problem that is affected by the number of consecutive work hours and shifts, the rest periods, and the predictability of work schedules. Sleepiness usually occurs during night shifts and is maximal at the end of the night. Impaired vigilance and performance occur around times of increased sleepiness and can seriously compromise workers' health and safety. Indeed, workers suffering from a shift work sleep-wake disorder can fall asleep involuntarily at work or while driving back home after a night shift. Working on atypical shifts has important socioeconomic impacts as it leads to an increased risk of accidents, workers' impairment and danger to public safety, especially at night. The aim of the present review is to review the circadian and sleep-wake disturbances associated with shift work as well as their medical impacts. Copyright © 2014. Published by Elsevier SAS.

Non-occupational physical activity levels of shift workers compared with non-shift workers

PubMed Central

Loef, Bette; Hulsegge, Gerben; Wendel-Vos, G C Wanda; Verschuren, W M Monique; Bakker, Marije F; van der Beek, Allard J; Proper, Karin I

2017-01-01

Objectives Lack of physical activity (PA) has been hypothesised as an underlying mechanism in the adverse health effects of shift work. Therefore, our aim was to compare non-occupational PA levels between shift workers and non-shift workers. Furthermore, exposure–response relationships for frequency of night shifts and years of shift work regarding non-occupational PA levels were studied. Methods Data of 5980 non-shift workers and 532 shift workers from the European Prospective Investigation into Cancer and Nutrition-Netherlands (EPIC-NL) were used in these cross-sectional analyses. Time spent (hours/week) in different PA types (walking/cycling/exercise/chores) and intensities (moderate/vigorous) were calculated based on self-reported PA. Furthermore, sports were operationalised as: playing sports (no/yes), individual versus non-individual sports, and non-vigorous-intensity versus vigorous-intensity sports. PA levels were compared between shift workers and non-shift workers using Generalized Estimating Equations and logistic regression. Results Shift workers reported spending more time walking than non-shift workers (B=2.3 (95% CI 1.2 to 3.4)), but shift work was not associated with other PA types and any of the sports activities. Shift workers who worked 1–4 night shifts/month (B=2.4 (95% CI 0.6 to 4.3)) and ≥5 night shifts/month (B=3.7 (95% CI 1.8 to 5.6)) spent more time walking than non-shift workers. No exposure–response relationships were found between years of shift work and PA levels. Conclusions Shift workers spent more time walking than non-shift workers, but we observed no differences in other non-occupational PA levels. To better understand if and how PA plays a role in the negative health consequences of shift work, our findings need to be confirmed in future studies. PMID:27872151

Non-occupational physical activity levels of shift workers compared with non-shift workers.

PubMed

Loef, Bette; Hulsegge, Gerben; Wendel-Vos, G C Wanda; Verschuren, W M Monique; Vermeulen, Roel C H; Bakker, Marije F; van der Beek, Allard J; Proper, Karin I

2017-05-01

Lack of physical activity (PA) has been hypothesised as an underlying mechanism in the adverse health effects of shift work. Therefore, our aim was to compare non-occupational PA levels between shift workers and non-shift workers. Furthermore, exposure-response relationships for frequency of night shifts and years of shift work regarding non-occupational PA levels were studied. Data of 5980 non-shift workers and 532 shift workers from the European Prospective Investigation into Cancer and Nutrition-Netherlands (EPIC-NL) were used in these cross-sectional analyses. Time spent (hours/week) in different PA types (walking/cycling/exercise/chores) and intensities (moderate/vigorous) were calculated based on self-reported PA. Furthermore, sports were operationalised as: playing sports (no/yes), individual versus non-individual sports, and non-vigorous-intensity versus vigorous-intensity sports. PA levels were compared between shift workers and non-shift workers using Generalized Estimating Equations and logistic regression. Shift workers reported spending more time walking than non-shift workers (B=2.3 (95% CI 1.2 to 3.4)), but shift work was not associated with other PA types and any of the sports activities. Shift workers who worked 1-4 night shifts/month (B=2.4 (95% CI 0.6 to 4.3)) and ≥5 night shifts/month (B=3.7 (95% CI 1.8 to 5.6)) spent more time walking than non-shift workers. No exposure-response relationships were found between years of shift work and PA levels. Shift workers spent more time walking than non-shift workers, but we observed no differences in other non-occupational PA levels. To better understand if and how PA plays a role in the negative health consequences of shift work, our findings need to be confirmed in future studies. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Associations between night work and BMI, alcohol, smoking, caffeine and exercise--a cross-sectional study.

PubMed

Buchvold, Hogne Vikanes; Pallesen, Ståle; Øyane, Nicolas M F; Bjorvatn, Bjørn

2015-11-12

Shift work is associated with negative health effects. Increased prevalence of several cardiovascular risk factors among shift workers/night workers compared with day workers have been shown resulting in increased risk of cardiovascular events among shift workers and night workers. Previous studies have taken a dichotomous approach to the comparison between day and night workers. The present study uses a continuous approach and provides such a new perspective to the negative effects of night work load as a possible risk factor for undesirable health effects. This cross sectional study (The SUrvey of Shift work, Sleep and Health (SUSSH)) uses data collected from December 2008 to March 2009. The study population consists of Norwegian nurses. The study collected information about demographic and lifestyle factors: Body Mass Index (BMI), smoking habits, alcohol consumption, caffeine consumption and exercise habits. The lifestyle parameters were evaluated using multiple hierarchical regression and binary logistic regression. Number of night shifts worked last year (NNL) was used as operationalization of night work load. Adjustment for possible confounders were made. Obesity was defined as BMI > 30. Alcohol Consumption was evaluated using the short form of the Alcohol Use Disorders Identification Test Consumption (AUDIT-C). Data were analyzed using SPSS version 22. We had data from 2059 nurses. NNL was significantly and positively associated with BMI, both when evaluated against BMI as a continuous parameter (Beta = .055, p < .05), and against obesity (OR = 1.01, 95 % CI = 1.00-1.01). The AUDIT-C score was significantly and positively associated with hours worked per week (OR = 1.03, 95 % CI = 1.01-1.05). We found a positive significant association between night work load and BMI. This suggests that workers with a heavy night work load might need special attention and frequent health checks due to higher risk of undesirable health effects.

Interleukin-6 Level among Shift and Night Workers in Japan: Cross-Sectional Analysis of the J-HOPE Study.

PubMed

Amano, Hoichi; Fukuda, Yoshiharu; Yokoo, Takashi; Yamaoka, Kazue

2018-03-27

Shift workers have a high risk of cardiovascular disease (CVD). Systemic inflammation measured has been associated with the risk of CVD onset, in addition to classical risk factors. However, the association between work schedule and inflammatory cytokine levels remains unclear. The purpose of this study was to examine the association between work schedule and interleukin-6 (IL-6)/high-sensitivity C-reactive protein (hs-CRP) levels among Japanese workers. The present cross-sectional study was a part of the Japanese Study of Health, Occupation and Psychosocial Factors Related Equity (J-HOPE). A total of 5259 persons who measured inflammatory cytokine were analyzed in this study. One-way analysis of variance was used to test log-transformed IL-6/hs-CRP differences by work schedule. Multiple regression analysis was used to examine the difference adjusted for other possible CVD risk factors. There were 3660 participants who had a regular work schedule; the remaining schedules were shift work without night work for 181 participants, shift work with night work for 1276 participants, and only night work for 142 participants. The unadjusted model showed that only night workers were significantly related to high levels of IL-6 compared with regular workers. Even in the multiple regression analysis, the higher level of IL-6 among only night workers remained significant (β=0.058, P=0.01). On the contrary, hs-CRP was not. The present study revealed that only night shift work is significantly associated with high levels of IL-6 in Japanese workers. These observations help us understand the mechanism for the association between work schedule and CVD onset.

Shift Work, Chronotype, and Melatonin Patterns among Female Hospital Employees on Day and Night Shifts.

PubMed

Leung, Michael; Tranmer, Joan; Hung, Eleanor; Korsiak, Jill; Day, Andrew G; Aronson, Kristan J

2016-05-01

Shift work-related carcinogenesis is hypothesized to be mediated by melatonin; however, few studies have considered the potential effect modification of this underlying pathway by chronotype or specific aspects of shift work such as the number of consecutive nights in a rotation. In this study, we examined melatonin patterns in relation to shift status, stratified by chronotype and number of consecutive night shifts, and cumulative lifetime exposure to shift work. Melatonin patterns of 261 female personnel (147 fixed-day and 114 on rotations, including nights) at Kingston General Hospital were analyzed using cosinor analysis. Urine samples were collected from all voids over a 48-hour specimen collection period for measurement of 6-sulfatoxymelatonin concentrations using the Buhlmann ELISA Kit. Chronotypes were assessed using mid-sleep time (MSF) derived from the Munich Chronotype Questionnaire (MCTQ). Sociodemographic, health, and occupational information were collected by questionnaire. Rotational shift nurses working nights had a lower mesor and an earlier time of peak melatonin production compared to day-only workers. More pronounced differences in mesor and acrophase were seen among later chronotypes, and shift workers working ≥3 consecutive nights. Among nurses, cumulative shift work was associated with a reduction in mesor. These results suggest that evening-types and/or shift workers working ≥3 consecutive nights are more susceptible to adverse light-at-night effects, whereas long-term shift work may also chronically reduce melatonin levels. Cumulative and current exposure to shift work, including nights, affects level and timing of melatonin production, which may be related to carcinogenesis and cancer risk. Cancer Epidemiol Biomarkers Prev; 25(5); 830-8. ©2016 AACR. ©2016 American Association for Cancer Research.

Enhanced preference for high-fat foods following a simulated night shift.

PubMed

Cain, Sean W; Filtness, Ashleigh J; Phillips, Craig L; Anderson, Clare

2015-05-01

Shift workers are prone to obesity and associated co-morbidities such as diabetes and cardiovascular disease. Sleep restriction associated with shift work results in dramatic endocrine and metabolic effects that predispose shift workers to these adverse health consequences. While sleep restriction has been associated with increased caloric intake, food preference may also play a key role in weight gain associated with shift work. This study examined the impact of an overnight simulated night shift on food preference. Sixteen participants [mean 20.1, standard deviation (SD) 1.4 years; 8 women] underwent a simulated night shift and control condition in a counterbalanced order. On the following morning, participants were provided an opportunity for breakfast that included high- and low-fat food options (mean 64.8% and 6.4% fat, respectively). Participants ate significantly more high-fat breakfast items after the simulated night shift than after the control condition [167.3, standard error of the mean (SEM 28.7) g versus 211.4 (SEM 35.6) g; P=0.012]. The preference for high-fat food was apparent among the majority of individuals following the simulated night shift (81%), but not for the control condition (31%). Shift work and control conditions did not differ, however, in the total amount of food or calories consumed. A simulated night shift leads to preference for high-fat food during a subsequent breakfast opportunity. These results suggest that food choice may contribute to weight-related chronic health problems commonly seen among night shift workers.

Neuroendocrine recovery after 2-week 12-h day and night shifts: an 11-day follow-up.

PubMed

Merkus, Suzanne L; Holte, Kari Anne; Huysmans, Maaike A; Hansen, Åse Marie; van de Ven, Peter M; van Mechelen, Willem; van der Beek, Allard J

2015-02-01

The study aimed to investigate the course and duration of neuroendocrine recovery after 2-week 12-h day and night shift working periods and to study whether there were differences in recovery between the shift groups. Twenty-nine male offshore employees working 2-week 12-h shift tours participated in the study; 15 participated after a day shift tour and 14 after a night shift tour. Salivary cortisol was assessed at awakening, 30 min after awakening, and before bedtime on the 1st, 4th, 7th, and 11th day of the free period, with a reference day prior to the offshore tour. Differences were tested using generalised estimating equations analysis. Compared to the reference day, night shift workers had a significantly flatter cortisol profile on the 1st day off, significantly lower cortisol concentrations at 30 min after awakening on day 4 and at awakening on day 7, and a significantly smaller decline to evening concentration on days 4 and 11. Compared to the reference day, day shift workers only showed a significantly lower cortisol concentration at awakening on the 1st day off. Compared to day workers, night shift workers had a flatter profile on the 1st day off and a lower cortisol concentration at awakening on the 4th day. Following 2-week 12-h night shift working periods, recovery was not fully complete up to day 11. Following 2-week 12-h day shift working periods, an indication of incomplete recovery was found on the 1st day off, with full recovery reached on day 4.

Randomised controlled trial of the efficacy of a blue-enriched light intervention to improve alertness and performance in night shift workers.

PubMed

Sletten, Tracey L; Ftouni, Suzanne; Nicholas, Christian L; Magee, Michelle; Grunstein, Ronald R; Ferguson, Sally; Kennaway, David J; O'Brien, Darren; Lockley, Steven W; Rajaratnam, Shantha M W

2017-11-01

Night workers often experience high levels of sleepiness due to misalignment of the sleep-wake cycle from the circadian pacemaker, in addition to acute and chronic sleep loss. Exposure to light, in particular short wavelength light, can improve alertness and neurobehavioural performance. This randomised controlled trial examined the efficacy of blue-enriched polychromatic light to improve alertness and neurobehavioural performance in night workers. Participants were 71 night shift workers (42 males; 32.8±10.5 years) who worked at least 6 hours between 22:00 and 08:00 hours. Sleep-wake logs and wrist actigraphy were collected for 1-3 weeks, followed by 48-hour urine collection to measure the circadian 6-sulphatoxymelatonin (aMT6s) rhythm. On the night following at least two consecutive night shifts, workers attended a simulated night shift in the laboratory which included subjective and objective assessments of sleepiness and performance. Workers were randomly assigned for exposure to one of two treatment conditions from 23:00 hours to 07:00 hours: blue-enriched white light (17 000 K, 89 lux; n=36) or standard white light (4000 K, 84 lux; n=35). Subjective and objective sleepiness increased during the night shift in both light conditions (p<0.05, η p 2 =0.06-0.31), but no significant effects of light condition were observed. The 17 000 K light, however, did improve subjective sleepiness relative to the 4000 K condition when light exposure coincided with the time of the aMT6s peak (p<0.05, d=0.41-0.60). This study suggests that, while blue-enriched light has potential to improve subjective sleepiness in night shift workers, further research is needed in the selection of light properties to maximise the benefits. The Australian New Zealand Clinical Trials Registry ACTRN12610000097044 (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=320845&isReview=true). © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Shift work parameters and disruption of diurnal cortisol production in female hospital employees.

PubMed

Hung, Eleanor Wai Man; Aronson, Kristan J; Leung, Michael; Day, Andrew; Tranmer, Joan

2016-01-01

Shift work is associated with an increased risk of cardiovascular diseases (CVD). Disruption of cortisol production is a potential underlying mechanism. This study explored the associations of diurnal quantity and pattern of cortisol production in relation to (1) current shift work status (exclusive day versus rotating days and nights), (2) years of past shift work and (3) parameters of rotating shift work (timing, length and intensity). Female hospital employees (160 day workers and 168 rotating shift workers) from southeastern Ontario, Canada, participated in a cross-sectional study. Participants completed a baseline questionnaire and measures of body height, weight, and waist circumference were taken. Midstream urine samples were collected over two separate 24-hour periods to measure creatinine-adjusted cortisol. Total diurnal cortisol production and pattern were described with two measures of the area under the curve. The effect of shift work on cortisol was modeled using multivariable linear regression analyses. Cortisol production in day workers and shift workers on their day shift were similar; however, shift workers on the night shift had flatter diurnal cortisol curves and produced less cortisol. This suggests that night work is associated with an acute attenuation of cortisol production.

Sleep Loss, Circadian Mismatch, and Abnormalities in Reorienting of Attention in Night Workers with Shift Work Disorder

PubMed Central

Gumenyuk, Valentina; Howard, Ryan; Roth, Thomas; Korzyukov, Oleg; Drake, Christopher L.

2014-01-01

Study Objectives: Permanent night-shift workers may develop shift-work disorder (SWD). In the current study, we evaluated neurophysiological and behavioral indices of distractibility across times prior to the night shift (T1), during night hours (T2), and after acute sleep deprivation (T3) in permanent hospital night workers with and without SWD. Methods: Ten asymptomatic night workers (NW) and 18 NW with SWD participated in a 25-h sleep deprivation study. Circadian phase was evaluated by dim-light salivary melatonin onset (DLMO). Objective sleepiness was evaluated using the Multiple Sleep Latency Test (MSLT). Electrophysiological distractibility was evaluated by brain event-related potentials (ERP), whereas behavioral distractibility was evaluated by performance on a visual task in an auditory-visual distraction paradigm. Statistical analyses: Comparisons of ERP results were performed by repeated-measures analysis of variance, and t-tests were used where appropriate. A Mann-Whitney U test was used for comparison of variables (MLST, Stanford Sleepiness Scale, and DLMO) that deviated from normal. Results: First, in the SWD group, the reorienting negativity ERP amplitude was significantly attenuated compared to that in the NW group. Second, the SWD group had shorter MSLT during night shift hours (4.8 ± 4.9 min) compared to that in NW (7.8 ± 3.7 min; U = 47; z = -2.1; P < 0.03). Third, NW with SWD had a DLMO at 20:27 ± 5.0 h, whereas healthy NW had a DLMO at 05:00 ± 3.4 h (U = 43.5; z = -2.22, P < 0.03). Finally, acute sleep deprivation impaired behavioral performance and the P3a ERP in both groups. Conclusions: Our results demonstrate specific deficits in neurophysiological activity in the attentional domain among the shift-work disorder group relative to night workers. Citation: Gumenyuk V; Howard R; Roth T; Korzyukov O; Drake CL. Sleep loss, circadian mismatch, and abnormalities in reorienting of attention in night workers with shift work disorder. SLEEP 2014;37(3):545-556. PMID:24587577

Effects of napping on sleepiness and sleep-related performance deficits in night-shift workers: a systematic review.

PubMed

Ruggiero, Jeanne S; Redeker, Nancy S

2014-04-01

Night-shift workers are prone to sleep deprivation, misalignment of circadian rhythms, and subsequent sleepiness and sleep-related performance deficits. The purpose of this narrative systematic review is to critically review and synthesize the scientific literature regarding improvements in sleepiness and sleep-related performance deficits following planned naps taken during work-shift hours by night workers and to recommend directions for future research and practice. We conducted a literature search using the Medline, PsychInfo, CINAHL, Cochrane Library, and Health and Safety Science Abstracts databases and included English-language quasi-experimental and experimental studies that evaluated the effects of a nighttime nap taken during a simulated or actual night-work shift. We identified 13 relevant studies, which consisted primarily of small samples and mixed designs. Most investigators found that, despite short periods of sleep inertia immediately following naps, night-shift napping led to decreased sleepiness and improved sleep-related performance. None of the studies examined the effects of naps on safety outcomes in the workplace. Larger-scale randomized clinical trials of night-shift napping and direct safety outcomes are needed prior to wider implementation.

Night shift work at specific age ranges and chronic disease risk factors.

PubMed

Ramin, Cody; Devore, Elizabeth E; Wang, Weike; Pierre-Paul, Jeffrey; Wegrzyn, Lani R; Schernhammer, Eva S

2015-02-01

We examined the association of night shift work history and age when night shift work was performed with cancer and cardiovascular disease risk factors among 54 724 women in the Nurses' Health Study (NHS) II. We calculated age-adjusted and socioeconomic status-adjusted means and percentages for cancer and cardiovascular risk factors in 2009 across categories of night shift work history. We used multivariable-adjusted logistic regression to estimate odds ratios (ORs) and 95% CIs for key risk factors among 54 724 participants (72% ever shift workers). We further examined these associations by age (20-25, 26-35, 36-45 and 46+ years) at which shift work was performed. Ever night shift workers had increased odds of obesity (body mass index ≥30 kg/m(2); OR=1.37, 95% CI 1.31 to 1.43); higher caffeine intake (≥131 mg/day; OR=1.16, 95% CI 1.12 to 1.22) and total calorie intake (≥1715 kcal/day; OR=1.09, 95% CI 1.04 to 1.13); current smoking (OR=1.30, 95% CI 1.19 to 1.42); and shorter sleep durations (≤7 h of sleep/day; OR=1.19, 95% CI 1.15 to 1.24) compared to never night shift workers. These estimates varied depending on age at which night work was performed, with a suggestion that night shift work before age 25 was associated with fewer risk factors compared to night shift work at older ages. Our results indicate that night shift work may contribute to an adverse chronic disease risk profile, and that risk factors may vary depending on the age at which night shift work was performed. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Current and cumulative night shift work and subclinical atherosclerosis: results of the Gutenberg Health Study.

PubMed

Jankowiak, S; Backé, E; Liebers, F; Schulz, A; Hegewald, J; Garthus-Niegel, S; Nübling, M; Blankenberg, S; Pfeiffer, N; Lackner, K J; Beutel, M; Blettner, M; Münzel, T; Wild, P S; Seidler, A; Letzel, S; Latza, U

2016-11-01

The study examines the association between exposure to current and cumulative night shift work and subclinical parameters of atherosclerosis. Participants of a population-based cohort study (the Gutenberg Health Study, N = 15,010) aged 35-64 years were examined at baseline (2007-2012). Investigations included measurements of arterial stiffness, vascular function [reactive hyperaemia (RH) index], and intima media thickness (IMT). Also, a complete job history (including up to 15 periods), occupational exposures, a variety of lifestyle, and dispositional variables were enquired. Night shift work was performed by 1071 out of 8065 currently employed individuals. The strongest association after adjustment for age, sex, job complexity level, being a manager, overtime work, and noise appeared for more than 660 night shifts within the last 10 years and a significantly increased arterial stiffness of 0.33 m/s. This reflects a 4 % flow velocity increase for individuals with more than 660 night shifts compared to non-night workers. Regarding the entire professional life, night shift workers showed a significantly decreased vascular function by -0.054 RH index points by using the same adjustment. IMT values did not differ statistically from non-night workers. Lifestyle and dispositional factors showed an influence on all used subclinical atherosclerosis parameters. The cross-sectional results demonstrate an association between night work and detrimental changes in the atherosclerotic process. The association is more pronounced with more years in night shift and is partly explained by lifestyle and dispositional factors. Longitudinal analyses are necessary to confirm the results.

The association between anxiety, hunger, the enjoyment of eating foods and the satiety after food intake in individuals working a night shift compared with after taking a nocturnal sleep: A prospective and observational study.

PubMed

Santa Cecília Silva, Ane Andrade; Lopes, Tássia do Vale Cardoso; Teixeira, Kely Raspante; Mendes, Jordane Amaral; de Souza Borba, Matheus Eduardo; Mota, Maria Carliana; Waterhouse, Jim; Crispim, Cibele Aparecida

2017-01-01

Subjective responses to meals are altered by shortened sleep time and anxiety state, but this effect has been poorly studied in shift workers - who act as a typical model concerning sleep restriction and present high levels of anxiety. The objective of this study was to compare subjective perceptions of meals and the levels of anxiety in the same subjects after working night shifts and after taking a nocturnal sleep, and to investigate associations between the responses to meals and the levels of anxiety under these two conditions. The study evaluated 34 male permanent night-shift workers who worked a 12-h shift followed by a 36-h rest period. Evaluations included: sleep pattern (on three days after working night shifts and after sleeping at night); hunger, enjoyment of eating foods and satiety after a meal (evaluated by visual analogue scales on three non-consecutive days after working night shifts and after nocturnal sleeps); and state of anxiety (on a day after working a night shift and a day after a nocturnal sleep). In the days following a night shift, workers had higher mean hunger scores before lunch and higher anxiety scores than when they had slept at night (p = 0.007 and 0.001, respectively). Linear regression indicated that, after a night shift, anxiety scores were negatively associated with hunger before breakfast (p = 0.04) and lunch (p = 0.03), the enjoyment of eating foods (p = 0.03) and the number of meals eaten during the course of the 24 h (p = 0.03). It is concluded that night shifts increase mean hunger and anxiety scores. Anxiety levels seem to interfere with the responses associated with food consumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of partial circadian adjustments on sleep and vigilance quality during simulated night work.

PubMed

Chapdelaine, Simon; Paquet, Jean; Dumont, Marie

2012-08-01

In most situations, complete circadian adjustment is not recommended for night workers. With complete adjustment, workers experience circadian misalignment when returning on a day-active schedule, causing repeated circadian phase shifts and internal desynchrony. For this reason, partial circadian realignment was proposed as a good compromise to stabilize internal circadian rhythms in night shift workers. However, the extent of partial circadian adjustment necessary to improve sleep and vigilance quality is still a matter of debate. In this study, the effects of small but statistically significant partial circadian adjustments on sleep and vigilance quality were assessed in a laboratory simulation of night work to determine whether they were also of clinical significance. Partial adjustments obtained by phase delay or by phase advance were quantified not only by the phase shift of dim light salivary melatonin onset, but also by the overlap of the episode of melatonin production with the sleep-wake cycle adopted during simulated night work. The effects on daytime sleep and night-time vigilance quality were modest. However, they suggest that even small adjustments by phase delay may decrease the accumulation of sleep debt, whereas the advance strategy improves subjective alertness and mood during night work. Furthermore, absolute phase shifts, by advance or by delay, were associated with improved subjective alertness and mood during the night shift. These strategies need to be tested in the field, to determine whether they can be adapted to real-life situations and provide effective support to night workers. © 2012 European Sleep Research Society.

[Possibilities and limits of sleep recovery for night-nursing workers].

PubMed

de Medeiros, Soraya Maria; de Macêdo, Maria Lúcia Azevedo Ferreira; de Oliveira, Jonas Sâmi Albuquerque; Ribeiro, Laiane Medeiros

2009-03-01

The present study had the objective of investigating the possibilities/limits of sleep recovery in women workers with medium level in nursing that develop their activities in night shifts in a first-aid clinic at a public hospital in Natal, Rio Grande do Norte, Brazil. This was an analytic study, with a qualitative approach which used the technique of thematic oral history Fifteen women workers with medium level in nursing were interviewed. The following empirical categories were defined: night shift work and night sleep and night rest at work environment Physiological and psychological sufferings are evident on their speech as well as what the lack of sleep causes in health and personal life of these women workers, making the overload of work clear and also the sociocultural imperfections of feminine gender

Meals, snacks and food choices in Brazilian shift workers with high energy expenditure.

PubMed

de Assis, M A A; Nahas, M V; Bellisle, F; Kupek, E

2003-08-01

To describe the food intake of garbage collectors, who works in three shifts, in terms of meal and snack frequency, content, time distribution and the contribution of various popular foods to the total diet. Sixty-six Brazilian garbage collectors, who work in morning, afternoon, and night shift, participated in the present study. The quantitative methods used were a combination of one 24-h recall and two 24-h records during three nonconsecutive work days. The qualitative method used was the food-based classification of eating episodes model modified in order to define meals or snacks in three categories of events: meals with three food groups of high nutrient density (three HND meals), meals with two food groups of high nutrient density (two HND meals) and snacks, composed of only one food category of high nutrient density. The total number of eating events per day was significantly higher for night shift workers. Over 24-h, 'two HND meals' were the most common events and contributed the most energy, in all three shifts. Night shift workers ate more at dawn and less in the morning than other shifts. In all three shifts, meat was the most important food contributing to energy intake. Different work schedules did not affect the relative frequency of meal types and snacks or their contribution to daily energy intake, but affected the daily distribution of eating events, with a redistribution of intake from day to night in night shift workers.

Associations between number of consecutive night shifts and impairment of neurobehavioral performance during a subsequent simulated night shift.

PubMed

Magee, Michelle; Sletten, Tracey L; Ferguson, Sally A; Grunstein, Ronald R; Anderson, Clare; Kennaway, David J; Lockley, Steven W; Rajaratnam, Shantha Mw

2016-05-01

This study aimed to investigate sleep and circadian phase in the relationships between neurobehavioral performance and the number of consecutive shifts worked. Thirty-four shift workers [20 men, mean age 31.8 (SD 10.9) years] worked 2-7 consecutive night shifts immediately prior to a laboratory-based, simulated night shift. For 7 days prior, participants worked their usual shift sequence, and sleep was assessed with logs and actigraphy. Participants completed a 10-minute auditory psychomotor vigilance task (PVT) at the start (~21:00 hours) and end (~07:00 hours) of the simulated night shift. Mean reaction times (RT), number of lapses and RT distribution was compared between those who worked 2-3 consecutive night shifts versus those who worked 4-7 shifts. Following 4-7 shifts, night shift workers had significantly longer mean RT at the start and end of shift, compared to those who worked 2-3 shifts. The slowest and fastest 10% RT were significantly slower at the start, but not end, of shift among participants who worked 4-7 nights. Those working 4-7 nights also demonstrated a broader RT distribution at the start and end of shift and had significantly slower RT based on cumulative distribution analysis (5 (th), 25 (th), 50 (th), 75 (th)percentiles at the start of shift; 75th percentile at the end of shift). No group differences in sleep parameters were found for 7 days and 24 hours prior to the simulated night shift. A greater number of consecutive night shifts has a negative impact on neurobehavioral performance, likely due to cognitive slowing.

Ocular Measures of Sleepiness Are Increased in Night Shift Workers Undergoing a Simulated Night Shift Near the Peak Time of the 6-Sulfatoxymelatonin Rhythm

PubMed Central

Ftouni, Suzanne; Sletten, Tracey L.; Nicholas, Christian L.; Kennaway, David J.; Lockley, Steven W.; Rajaratnam, Shantha M.W.

2015-01-01

Study Objectives: The study examined the relationship between the circadian rhythm of 6-sulphatoxymelatonin (aMT6s) and ocular measures of sleepiness and neurobehavioral performance in shift workers undergoing a simulated night shift. Methods: Twenty-two shift workers (mean age 33.4, SD 11.8 years) were tested at approximately the beginning (20:00) and the end (05:55) of a simulated night shift in the laboratory. At the time point corresponding to the end of the simulated shift, 14 participants were classified as being within range of 6-sulphatoxymelatonin (aMT6s) acrophase— defined as 3 hours before or after aMT6s peak—and 8 were classified as outside aMT6s acrophase range. Participants completed the Karolinska Sleepiness Scale (KSS) and the auditory psychomotor vigilance task (aPVT). Waking electroencephalography (EEG) was recorded and infrared reflectance oculography was used to collect ocular measures of sleepiness: positive and negative amplitude/velocity ratio (PosAVR, NegAVR), mean blink total duration (BTD), the percentage of eye closure (%TEC), and a composite score of sleepiness levels (Johns Drowsiness Scale; JDS). Results: Participants who were tested within aMT6s acrophase range displayed higher levels of sleepiness on ocular measures (%TEC, BTD, PosAVR, JDS), objective sleepiness (EEG delta power frequency band), subjective ratings of sleepiness, and neurobehavioral performance, compared to those who were outside aMT6s acrophase range. Conclusions: The study demonstrated that objective ocular measures of sleepiness are sensitive to circadian rhythm misalignment in shift workers. Citation: Ftouni S, Sletten TL, Nicholas CL, Kennaway DJ, Lockley SW, Rajaratnam SM. Ocular measures of sleepiness are increased in night shift workers undergoing a simulated night shift near the peak time of the 6-sulfatoxymelatonin rhythm. J Clin Sleep Med 2015;11(10):1131–1141. PMID:26094925

Effects of long working hours and the night shift on severe sleepiness among workers with 12-hour shift systems for 5 to 7 consecutive days in the automobile factories of Korea.

PubMed

Son, Mia; Kong, Jeong-Ok; Koh, Sang-Baek; Kim, Jaeyoung; Härmä, Mikko

2008-12-01

We investigated the effects of 12-hour shift work for five to seven consecutive days and overtime on the prevalence of severe sleepiness in the automobile industry in Korea. [Correction added after online publication 28 Nov: Opening sentence of the summary has been rephrased for better clarity.] A total of 288 randomly selected male workers from two automobile factories were selected and investigated using questionnaires and sleep-wake diaries in South Korea. The prevalence of severe sleepiness at work [i.e. Karolinska Sleepiness Scale (KSS) score of 7 or higher] was modeled using marginal logistic regression and included theoretical risk factors related to working hours and potential confounding factors related to socio-economic status, work demands, and health behaviors. Factors related to working hours increased the risk for severe sleepiness at the end of the shift in the following order: the night shift [odds ratio (OR): 4.7; 95% confidence interval (CI): 3.6-6.0)], daily overtime (OR: 2.2; 95% CI: 1.7-2.9), weekly overtime (OR: 1.6; 95% CI: 1.0-2.6), and night overtime (OR: 1.6; 95% CI: 0.8-3.0). Long working hours and shift work had a significant interactive effect for severe sleepiness at work. Night shift workers who worked for 12 h or more a day were exposed to a risk of severe sleepiness that was 7.5 times greater than day shift workers who worked less than 11 h. Night shifts and long working hours were the main risk factors for severe sleepiness among automobile factory workers in Korea. Night shifts and long working hours have a high degree of interactive effects resulting in severe sleepiness at work, which highlight the need for immediate measures to address these characteristics among South Korean labor force patterns.

Increased errors and decreased performance at night: A systematic review of the evidence concerning shift work and quality.

PubMed

de Cordova, Pamela B; Bradford, Michelle A; Stone, Patricia W

2016-02-15

Shift workers have worse health outcomes than employees who work standard business hours. However, it is unclear how this poorer health shift may be related to employee work productivity. The purpose of this systematic review is to assess the relationship between shift work and errors and performance. Searches of MEDLINE/PubMed, EBSCOhost, and CINAHL were conducted to identify articles that examined the relationship between shift work, errors, quality, productivity, and performance. All articles were assessed for study quality. A total of 435 abstracts were screened with 13 meeting inclusion criteria. Eight studies were rated to be of strong, methodological quality. Nine studies demonstrated a positive relationship that night shift workers committed more errors and had decreased performance. Night shift workers have worse health that may contribute to errors and decreased performance in the workplace.

[Shift and night work and mental health].

PubMed

Sancini, Angela; Ciarrocca, Manuela; Capozzella, Assunta; Corbosiero, Paola; Fiaschetti, Maria; Caciari, Tiziana; Cetica, Carlotta; Scimitto, Lara; Ponticiello, Barnaba Giuseppina; Tasciotti, Zaira; Schifano, Maria Pia; Andreozzit, Giorgia; Tomei, Francesco; Tomei, Gianfranco

2012-01-01

Aim of our study was to evaluate the influence that shift work and night work could have on mental health. A review of literary articles from 1990 to 2011 on shift work and night work was carried out. The results of this review confirmed that the shift work and night work affect mental health with the onset of neuropsychological disorders such as mood disorders, anxiety, nervousness, depressive anxiety syndromes, chronic fatigue and chronic insomnia irritability, sleep disturbances, reduction in levels of attention, cognitive impairments, alteration of circadian rhythm. Night work and shift work cause severe desynchronization of the cronobiological rhythms and a disruption of social life with negative effects on performance at work, on health and on social relationships. In the light of these results and recognizing shift work and night work as risk factors for the health of workers is necessary to implement preventive and periodic health checks by the occupational doctor to ensure the health and safety of workers taking account of the different environmental and individual factors.

Nested case-control study of night shift work and breast cancer risk among women in the Danish military.

PubMed

Hansen, Johnni; Lassen, Christina F

2012-08-01

Growing but limited evidence suggests that night shift work is associated with breast cancer. The authors conducted a nationwide case-control study nested within a cohort of 18,551 female military employees born in 1929-1968 to investigate the risk for breast cancer after night shift work and to explore the role of leisure time sun exposure and diurnal preference. The authors documented 218 cases of breast cancer (1990-2003) and selected 899 age-matched controls from the cohort by incidence density sampling. Information on shift work, sun exposure habits, diurnal preference and other potential confounders was obtained from a structured questionnaire. ORs were estimated by multivariate conditional logistic regression. Overall, the authors observed an adjusted OR of 1.4 (95% CI 0.9 to 2.1) among women with ever compared with never night shifts. The RR for breast cancer tended to increase with increasing number of years of night shift work (p=0.03) and with cumulative number of shifts (p=0.02),with a neutral risk for fewer than three night shifts per week. The OR for the group with the highest tertile of cumulative exposure was 2.3 (95% CI 1.2 to 4.6). The most pronounced effect of night shift work on breast cancer risk was observed in women with morning chronotype preference and intense night shifts (OR=3.9, 95% CI 1.6 to 9.5). Night shift workers tended to sunbathe more frequently than day workers. The results indicate that frequent night shift work increases the risk for breast cancer and suggest a higher risk with longer duration of intense night shifts. Women with morning preference who worked on night shifts tended to have a higher risk than those with evening preference.

Night-shift work and risk of compromised visual acuity among the workers in an electronics manufacturing company.

PubMed

Lin, Yu-Cheng; Ho, Kuo-Jung

2018-01-01

To evaluate the association between night-shift work exposure and visual health, this cross-sectional study utilized visual acuity, a surrogate measure for visual function, as a parameter, and performed an analysis comparing visual acuity between daytime and nighttime employees in an electronics manufacturing company. Data of personal histories, occupational records, physical examinations and blood tests was obtained from the electronic health records of workers. The total of 8280 workers including 3098 women and 5182 men, wearing their own daily used eyeglasses, were included in the final analysis. The mean age of the sample population was 34.7 years old (standard deviation = 5.4 years). All workers were divided into 3 work categories - consistent daytime worker (CDW), day-shift worker (DSW) and night-shift worker (NSW). The check-up results of glasses-corrected visual acuity (c-VA) were utilized to classify individuals as good (≥ 1.2, both eyes) and inadequate (< 0.8, the better eye) c-VA. Consistent daytime workers had the highest rate of good c-VA (42.5% vs. 25.1% DSW and 21.1% NSW, p = 0.047). Night-shift workers had the highest rate of inadequate c-VA (CDW, DSW and NSW: 2.6%, 6.2%, and 7.6%, p = 0.03) among all employees. After controlling for covariates, NSW were found at an increased risk for inadequate c-VA (adjusted odds ratio (ORa) = 2.7, 95% confidence interval (CI): 2.0-3.6, vs. CDW), and less likely to have good c-VA (ORa = 0.4, 95% CI: 0.4-0.5, vs. CDW). Night-shift work is moderately associated with compromised visual acuity of employees in this electronics manufacturing company. Int J Occup Med Environ Health 2018;31(1):71-79. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Optimal Shift Duration and Sequence: Recommended Approach for Short-Term Emergency Response Activations for Public Health and Emergency Management

PubMed Central

Burgess, Paula A.

2007-01-01

Since September 11, 2001, and the consequent restructuring of the US preparedness and response activities, public health workers are increasingly called on to activate a temporary round-the-clock staffing schedule. These workers may have to make key decisions that could significantly impact the health and safety of the public. The unique physiological demands of rotational shift work and night shift work have the potential to negatively impact decisionmaking ability. A responsible, evidence-based approach to scheduling applies the principles of circadian physiology, as well as unique individual physiologies and preferences. Optimal scheduling would use a clockwise (morning-afternoon-night) rotational schedule: limiting night shifts to blocks of 3, limiting shift duration to 8 hours, and allowing 3 days of recuperation after night shifts. PMID:17413074

Controlled patterns of daytime light exposure improve circadian adjustment in simulated night work.

PubMed

Dumont, Marie; Blais, Hélène; Roy, Joanie; Paquet, Jean

2009-10-01

Circadian misalignment between the endogenous circadian signal and the imposed rest-activity cycle is one of the main sources of sleep and health troubles in night shift workers. Timed bright light exposure during night work can reduce circadian misalignment in night workers, but this approach is limited by difficulties in incorporating bright light treatment into most workplaces. Controlled light and dark exposure during the daytime also has a significant impact on circadian phase and could be easier to implement in real-life situations. The authors previously described distinctive light exposure patterns in night nurses with and without circadian adaptation. In the present study, the main features of these patterns were used to design daytime light exposure profiles. Profiles were then tested in a laboratory simulation of night work to evaluate their efficacy in reducing circadian misalignment in night workers. The simulation included 2 day shifts followed by 4 consecutive night shifts (2400-0800 h). Healthy subjects (15 men and 23 women; 20-35 years old) were divided into 3 groups to test 3 daytime light exposure profiles designed to produce respectively a phase delay (delay group, n=12), a phase advance (advance group, n=13), or an unchanged circadian phase (stable group, n=13). In all 3 groups, light intensity was set at 50 lux during the nights of simulated night work. Salivary dim light melatonin onset (DLMO) showed a significant phase advance of 2.3 h (+/-1.3 h) in the advance group and a significant phase delay of 4.1 h (+/-1.3 h) in the delay group. The stable group showed a smaller but significant phase delay of 1.7 h (+/-1.6 h). Urinary 6-sulfatoxymelatonin (aMT6s) acrophases were highly correlated to salivary DLMOs. Urinary aMT6s acrophases were used to track daily phase shifts. They showed that phase shifts occurred rapidly and differed between the 3 groups by the 3rd night of simulated night work. These results show that significant phase shifts can be achieved in night workers by controlling daytime light exposure, with no nighttime intervention.

Influences on Dietary Choices during Day versus Night Shift in Shift Workers: A Mixed Methods Study

PubMed Central

Bonnell, Emily K.; Huggins, Catherine E.; Huggins, Chris T.; McCaffrey, Tracy A.; Palermo, Claire; Bonham, Maxine P.

2017-01-01

Shift work is associated with diet-related chronic conditions such as obesity and cardiovascular disease. This study aimed to explore factors influencing food choice and dietary intake in shift workers. A fixed mixed method study design was undertaken on a convenience sample of firefighters who continually work a rotating roster. Six focus groups (n = 41) were conducted to establish factors affecting dietary intake whilst at work. Dietary intake was assessed using repeated 24 h dietary recalls (n = 19). Interviews were audio recorded, transcribed verbatim, and interpreted using thematic analysis. Dietary data were entered into FoodWorks and analysed using Wilcoxon signed-rank test; p < 0.05 was considered significant. Thematic analysis highlighted four key themes influencing dietary intake: shift schedule; attitudes and decisions of co-workers; time and accessibility; and knowledge of the relationship between food and health. Participants reported consuming more discretionary foods and limited availability of healthy food choices on night shift. Energy intakes (kJ/day) did not differ between days that included a day or night shift but greater energy density (EDenergy, kJ/g/day) of the diet was observed on night shift compared with day shift. This study has identified a number of dietary-specific shift-related factors that may contribute to an increase in unhealthy behaviours in a shift-working population. Given the increased risk of developing chronic diseases, organisational change to support workers in this environment is warranted. PMID:28245625

Influences on Dietary Choices during Day versus Night Shift in Shift Workers: A Mixed Methods Study.

PubMed

Bonnell, Emily K; Huggins, Catherine E; Huggins, Chris T; McCaffrey, Tracy A; Palermo, Claire; Bonham, Maxine P

2017-02-26

Shift work is associated with diet-related chronic conditions such as obesity and cardiovascular disease. This study aimed to explore factors influencing food choice and dietary intake in shift workers. A fixed mixed method study design was undertaken on a convenience sample of firefighters who continually work a rotating roster. Six focus groups ( n = 41) were conducted to establish factors affecting dietary intake whilst at work. Dietary intake was assessed using repeated 24 h dietary recalls ( n = 19). Interviews were audio recorded, transcribed verbatim, and interpreted using thematic analysis. Dietary data were entered into FoodWorks and analysed using Wilcoxon signed-rank test; p < 0.05 was considered significant. Thematic analysis highlighted four key themes influencing dietary intake: shift schedule; attitudes and decisions of co-workers; time and accessibility; and knowledge of the relationship between food and health. Participants reported consuming more discretionary foods and limited availability of healthy food choices on night shift. Energy intakes (kJ/day) did not differ between days that included a day or night shift but greater energy density (ED energy , kJ/g/day) of the diet was observed on night shift compared with day shift. This study has identified a number of dietary-specific shift-related factors that may contribute to an increase in unhealthy behaviours in a shift-working population. Given the increased risk of developing chronic diseases, organisational change to support workers in this environment is warranted.

Postprandial metabolic profiles following meals and snacks eaten during simulated night and day shift work.

PubMed

Al-Naimi, S; Hampton, S M; Richard, P; Tzung, C; Morgan, L M

2004-01-01

Shift workers are known to have an increased risk of developing cardiovascular disease (CVD) compared with day workers. An important factor contributing to this increased risk could be the increased incidence of postprandial metabolic risk factors for CVD among shift workers, as a consequence of the maladaptation of endogenous circadian rhythms to abrupt changes in shift times. We have previously shown that both simulated and real shift workers showed relatively impaired glucose and lipid tolerance if a single test meal was consumed between 00:00-02:00 h (night shift) compared with 12:00-14:00 h (day shift). The objective of the present study was to extend these observations to compare the cumulative metabolic effect of consecutive snacks/meals, as might normally be consumed throughout a period of night or day shift work. In a randomized crossover study, eight healthy nonobese men (20-33 yrs, BMI 20-25kg/m2) consumed a combination of two meals and a snack on two occasions following a standardized prestudy meal, simulating night and day shift working (total energy 2500 kcal: 40% fat, 50% carbohydrate, 10% protein). Meals were consumed at 01:00/ 13:00 h and 07:00/19:00h, and the snack at 04:00/16:00 h. Blood was taken after an overnight fast, and for 8 h following the first meal on each occasion, for the measurement of glucose, insulin, triacylglycerol (TAG), and nonesterified fatty acids (NEFA). RM-ANOVA (factors time and shift) showed a significant effect of shift for plasma TAG, with higher levels on simulated night compared to day shift (p < 0.05). There was a trend toward an effect of shift for plasma glucose, with higher plasma glucose at night (p = 0.08), and there was a time-shift interaction for plasma insulin levels (p < 0.01). NEFA levels were unaffected by shift. Inspection of the area under the plasma response curve (AUC) following each meal and snack revealed that the differences in lipid tolerance occurred throughout the study, with greatest differences occurring following the mid-shift snack. In contrast, glucose tolerance was relatively impaired following the first night-time meal, with no differences observed following the second meal. Plasma insulin levels were significantly lower following the first meal (p < 0.05), but significantly higher following the second meal (p < 0.01) on the simulated night shift. These findings confirm our previous observations of raised postprandial TAG and glucose at night, and show that sequential meal ingestion has a more pronounced effect on subsequent lipid than carbohydrate tolerance.

The relationship between quality of sleep and night shift rotation interval.

PubMed

Kim, Jae Youn; Chae, Chang Ho; Kim, Young Ouk; Son, Jun Seok; Kim, Ja Hyun; Kim, Chan Woo; Park, Hyoung Ouk; Lee, Jun Ho; Kwon, Soon Il; Kwon, Sun Il

2015-01-01

Shift work is closely related with workers' health. In particular, sleep is thought to be affected by shift work. In addition, shift work has been reported to be associated with the type or direction of shift rotation, number of consecutive night shifts, and number of off-duty days. We aimed to analyze the association between the night shift rotation interval and the quality of sleep reported by Korean female shift workers. In total, 2,818 female shift workers from the manufacturing industry who received an employee physical examination at a single university hospital from January to August in 2014 were included. Subjects were classified into three groups (A, B, and C) by their night shift rotation interval. The quality of sleep was measured using the Korean version of the Pittsburgh Sleep Quality Index (PSQI). Descriptive analysis, univariate logistic regression, and multivariate logistic regression were performed. With group A as the reference, the odds ratio (OR) for having a seriously low quality of sleep was 1.456 (95% CI 1.171-1.811) and 2.348 (95% CI 1.852-2.977) for groups B and C, respectively. Thus, group C with the shortest night shift rotation interval was most likely to have a low quality of sleep. After adjustment for age, obesity, smoking status, alcohol consumption, exercise, being allowed to sleep during night shifts, work experience, and shift work experience, groups B and C had ORs of 1.419 (95% CI 1.134-1.777) and 2.238 (95% CI 1.737-2.882), respectively, compared to group A. Our data suggest that a shorter night shift rotation interval does not provide enough recovery time to adjust the circadian rhythm, resulting in a low quality of sleep. Because shift work is influenced by many different factors, future studies should aim to determine the most optimal shift work model and collect accurate, prospective data.

Sleep Duration and Chronic Fatigue Are Differently Associated with the Dietary Profile of Shift Workers

PubMed Central

Heath, Georgina; Coates, Alison; Sargent, Charli; Dorrian, Jillian

2016-01-01

Shift work has been associated with dietary changes. This study examined factors associated with the dietary profiles of shift workers from several industries (n = 118, 57 male; age = 43.4 ± 9.9 years) employed on permanent mornings, nights, or rotating 8-h or 12-h shifts. The dietary profile was assessed using a Food Frequency Questionnaire. Shift-related (e.g., sleep duration and fatigue), work-related (e.g., industry), and demographic factors (e.g., BMI) were measured using a modified version of the Standard Shift work Index. Mean daily energy intake was 8628 ± 3161 kJ. As a percentage of daily energy intake, all workers reported lower than recommended levels of carbohydrate (CHO, 45%–65%). Protein was within recommended levels (15%–25%). Permanent night workers were the only group to report higher than recommended fat intake (20%–35%). However, all workers reported higher than recommended levels of saturated fat (>10%) with those on permanent nights reporting significantly higher levels than other groups (Mean = 15.5% ± 3.1%, p < 0.05). Shorter sleep durations and decreased fatigue were associated with higher CHO intake (p ≤ 0.05) whereas increased fatigue and longer sleep durations were associated with higher intake of fat (p ≤ 0.05). Findings demonstrate sleep duration, fatigue, and shift schedule are associated with the dietary profile of shift workers. PMID:27916861

Sleep Duration and Chronic Fatigue Are Differently Associated with the Dietary Profile of Shift Workers.

PubMed

Heath, Georgina; Coates, Alison; Sargent, Charli; Dorrian, Jillian

2016-11-30

Shift work has been associated with dietary changes. This study examined factors associated with the dietary profiles of shift workers from several industries ( n = 118, 57 male; age = 43.4 ± 9.9 years) employed on permanent mornings, nights, or rotating 8-h or 12-h shifts. The dietary profile was assessed using a Food Frequency Questionnaire. Shift-related (e.g., sleep duration and fatigue), work-related (e.g., industry), and demographic factors (e.g., BMI) were measured using a modified version of the Standard Shift work Index. Mean daily energy intake was 8628 ± 3161 kJ. As a percentage of daily energy intake, all workers reported lower than recommended levels of carbohydrate (CHO, 45%-65%). Protein was within recommended levels (15%-25%). Permanent night workers were the only group to report higher than recommended fat intake (20%-35%). However, all workers reported higher than recommended levels of saturated fat (>10%) with those on permanent nights reporting significantly higher levels than other groups (Mean = 15.5% ± 3.1%, p < 0.05). Shorter sleep durations and decreased fatigue were associated with higher CHO intake ( p ≤ 0.05) whereas increased fatigue and longer sleep durations were associated with higher intake of fat ( p ≤ 0.05). Findings demonstrate sleep duration, fatigue, and shift schedule are associated with the dietary profile of shift workers.

Offshore fleet workers and the circadian adaptation of core body temperature, blood pressure and heart rate to 12-h shifts: a field study.

PubMed

Hansen, Jakob Hønborg; Geving, Ingunn Holmen; Reinertsen, Randi Eidsmo

2010-01-01

The aim of this study was to investigate the circadian adaptation of tcr (core body temperature), BP (blood pressure), HR (heart rate) and subjective sleep quality after 7 days of working 12-h night shifts in offshore fleet workers. Night workers (N = 7) (18:00-6:00) and day workers (N = 7) (6:00-18:00) were recruited from a Norwegian offshore company operating in the North Sea. We measured t(cr), BP and HR on days 1 and 7. An increase of 0.6 °C (p = .03) was observed within the group of night workers from day 1 to day 7. Between the night and day workers there was a significant difference of 0.6 °C from day 1 to day 7 (p = .01). Sleep latency and sleep length also showed significant differences between the groups (p = .01 and p = .04). There was an interaction effect in tiredness during the shift (p = .02). The significant increase in tcr indicates an adaptation in the night workers to the new working schedule, and the extended working hours and sleep deprivation are hypothesized to be the main cause of the increased t(cr). Light exposure, altered pattern of food availability and physical activity are likely to have contributed as well. Subjective sleep quality showed inconclusive results.

Adaptation to shift work: physiologically based modeling of the effects of lighting and shifts' start time.

PubMed

Postnova, Svetlana; Robinson, Peter A; Postnov, Dmitry D

2013-01-01

Shift work has become an integral part of our life with almost 20% of the population being involved in different shift schedules in developed countries. However, the atypical work times, especially the night shifts, are associated with reduced quality and quantity of sleep that leads to increase of sleepiness often culminating in accidents. It has been demonstrated that shift workers' sleepiness can be improved by a proper scheduling of light exposure and optimizing shifts timing. Here, an integrated physiologically-based model of sleep-wake cycles is used to predict adaptation to shift work in different light conditions and for different shift start times for a schedule of four consecutive days of work. The integrated model combines a model of the ascending arousal system in the brain that controls the sleep-wake switch and a human circadian pacemaker model. To validate the application of the integrated model and demonstrate its utility, its dynamics are adjusted to achieve a fit to published experimental results showing adaptation of night shift workers (n = 8) in conditions of either bright or regular lighting. Further, the model is used to predict the shift workers' adaptation to the same shift schedule, but for conditions not considered in the experiment. The model demonstrates that the intensity of shift light can be reduced fourfold from that used in the experiment and still produce good adaptation to night work. The model predicts that sleepiness of the workers during night shifts on a protocol with either bright or regular lighting can be significantly improved by starting the shift earlier in the night, e.g.; at 21:00 instead of 00:00. Finally, the study predicts that people of the same chronotype, i.e. with identical sleep times in normal conditions, can have drastically different responses to shift work depending on their intrinsic circadian and homeostatic parameters.

Does modifying the timing of meal intake improve cardiovascular risk factors? Protocol of an Australian pilot intervention in night shift workers with abdominal obesity.

PubMed

Bonham, Maxine P; Leung, Gloria K W; Davis, Rochelle; Sletten, Tracey L; Murgia, Chiara; Young, Morag J; Eikelis, Nina; Lambert, Elisabeth A; Huggins, Catherine E

2018-03-14

Shift work is an independent risk factor for cardiovascular disease (CVD). Shift workers who are awake overnight and sleep during the day are misaligned with their body's endogenous circadian rhythm. Eating at night contributes to this increased risk of CVD by forcing the body to actively break down and process nutrients at night. This pilot study aims to determine whether altering meal timing overnight, in a shift working population, will impact favourably on modifiable risk factors for CVD (postprandial bplasma lipids and glucose concentration). A randomised cross-over study with two 4-week test periods, separated by a minimum of a 2-week washout will be undertaken. The effectiveness of redistributing energy intake overnight versus ad libitum eating patterns on CVD risk factors will be examined in night shift workers (n=20), using a standard acute test meal challenge protocol. Primary outcomes (postprandial lipids and glucose) will be compared between the two conditions: post-intervention and post-control period using analysis of variance. Potential effect size estimates to inform sample size calculations for a main trial will also be generated. Ethics approval has been granted by the Monash University Human Research Ethics Committee (2017-8619-10329). Outcomes from this study will determine whether eliminating food intake for a defined period at night (1-6 am) impacts favourably on metabolic risk factors for CVD in night shift workers. Collective results from this novel trial will be disseminated through peer-reviewed journals, and national and international presentations. The results are essential to inform health promotion policies and guidelines for shift workers, especially those who aim to improve their metabolic health. ACTRN12617000791336; Pre-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Short sleep duration among workers--United States, 2010.

PubMed

2012-04-27

Insufficient sleep can have serious and sometimes fatal consequences for fatigued workers and others around them. For example, an estimated 20% of vehicle crashes are linked to drowsy driving. The National Sleep Foundation recommends that healthy adults sleep 7-9 hours per day. To assess the prevalence of short sleep duration among workers, CDC analyzed data from the 2010 National Health Interview Survey (NHIS). The analysis compared sleep duration by age group, race/ethnicity, sex, marital status, education, and employment characteristics. Overall, 30.0% of civilian employed U.S. adults (approximately 40.6 million workers) reported an average sleep duration of ≤6 hours per day. The prevalence of short sleep duration (≤6 hours per day) varied by industry of employment (range: 24.1%-41.6%), with a significantly higher rate of short sleep duration among workers in manufacturing (34.1%) compared with all workers combined. Among all workers, those who usually worked the night shift had a much higher prevalence of short sleep duration (44.0%, representing approximately 2.2 million night shift workers) than those who worked the day shift (28.8%, representing approximately 28.3 million day shift workers). An especially high prevalence of short sleep duration was reported by night shift workers in the transportation and warehousing (69.7%) and health-care and social assistance (52.3%) industries. Targeted interventions, such as evidence-based shift system designs that improve sleep opportunities and evidence-based training programs on sleep and working hours tailored for managers and employees, should be implemented to protect the health and safety of workers, their coworkers, and the public.

Experience and limited lighting may affect sleepiness of tunnel workers

PubMed Central

2014-01-01

Background Working on shifts, especially on a night shift, influences the endogenous sleep regulation system leading to diminished sleep time and increased somnolence. We attempted to evaluate the impact of shifts on sleepiness and correlate the sleepiness score to the experience in a shift schedule. Materials and methods This cross-sectional study consists of 42 male and 2 female workers involved in a tunnel construction. They underwent spirometry, pulse oximetry and were asked to complete the Epworth Sleepiness Scale questionnaire. Results Statistical analysis revealed that workers of lower Epworth had a mean age of 43.6 years, compared to the mean age of 36.4 years of workers with higher Epworth. Furthermore, workers of lower Epworth were characterized by a mean number of shift years equal to 14.8, while those of higher Epworth possessed a mean number of shift years equal to 8. The shift schedule did not reveal any statistically significant correlation. Conclusions Workers employed for a longer time had diminished sleepiness. However, there is no relationship between night shifts and sleepiness, possibly because of exposure to artificial lighting in the construction site. PMID:24993796

Experience and limited lighting may affect sleepiness of tunnel workers.

PubMed

Lykouras, Dimosthenis; Karkoulias, Kiriakos; Patouchas, Dimitrios; Lakoumentas, John; Sampsonas, Fotis; Tranou, Magdalini-Konstantina; Faliagka, Evanthia; Tsakalidis, Athanasios; Spiropoulos, Kostas

2014-07-03

Working on shifts, especially on a night shift, influences the endogenous sleep regulation system leading to diminished sleep time and increased somnolence. We attempted to evaluate the impact of shifts on sleepiness and correlate the sleepiness score to the experience in a shift schedule. This cross-sectional study consists of 42 male and 2 female workers involved in a tunnel construction. They underwent spirometry, pulse oximetry and were asked to complete the Epworth Sleepiness Scale questionnaire. Statistical analysis revealed that workers of lower Epworth had a mean age of 43.6 years, compared to the mean age of 36.4 years of workers with higher Epworth. Furthermore, workers of lower Epworth were characterized by a mean number of shift years equal to 14.8, while those of higher Epworth possessed a mean number of shift years equal to 8. The shift schedule did not reveal any statistically significant correlation. Workers employed for a longer time had diminished sleepiness. However, there is no relationship between night shifts and sleepiness, possibly because of exposure to artificial lighting in the construction site.

Objective working hour characteristics and work-life conflict among hospital employees in the Finnish public sector study.

PubMed

Karhula, Kati; Puttonen, Sampsa; Ropponen, Annina; Koskinen, Aki; Ojajärvi, Anneli; Kivimäki, Mika; Härmä, Mikko

2017-01-01

This epidemiological cohort study, based on Finnish public sector data, investigated the associations between objective working hour characteristics and work-life conflict in day and shift work. The comprehensive data of hospital workers (n = 8 931, 92% women, average age 45 years), consisted of survey responses from 2012, linked with the payroll data of working hour characteristics from 91 days preceding the survey. Logistic regression analysis was used to investigate the associations between working hour characteristics and experiencing work-life conflict often/very often. The analyses were adjusted for age (< 39, 40-49 and >50 years), sex, level of education, marital status, number of small (0-6 years) and school-aged (7-18 years) children, and the overall stressfulness of the life situation. We also conducted stratified analyses of age and sex on the basis of significant interactions. Difficulties in combining work and life were more often associated with shift work without night shifts and shift work with night shifts than with day work (41% and 34 versus 27%; OR for shift work with night shifts 1.78, 95% CI 1.59-2.00, OR for shift work without night shifts 1.42, 95% CI 1.26-1.60). A high proportion (> 25%) of long (> 40h, (OR 1.26, 95% 1.14-1.39) and very long (> 48h, OR 1.31, 95% CI 1.15-1.49) weekly working hours were associated with work-life conflict, and in the stratified analysis, the latter was also true among women (OR 1.54, 95% CI 1.25-1.89). Of the unsocial working hour characteristics, a relatively large amount (> 10% of all shifts) of evening (OR 1.56, 95% CI 1.41-1.72) and night shifts (OR 1.46, 95%CI 1.32-1.61), a high proportion (> 25% of all shifts) of quick returns (< 11h) (OR 1.46, 95% CI 1.31-1.63), and weekend work (OR 1.44, 95% CI 1.31-1.58) were associated with work-life conflict. A large amount of single days off (> 25% of all days off) was associated with work-life conflict among men (OR 1.90, 95% CI 1.11-3.25), but not in the whole sample. When the two types of shift work were analyzed separately, shift work without night shifts and very long work weeks had higher odds (OR 1.47, 95% CI 1.20-1.80) of work-life conflict than shift work with night shifts. Conversely, weekend work and evening shifts had higher odds of work-life conflict among shift workers with night shifts (OR 1.74, 95% 1.55-1.96; (OR 1.57, 95% CI 1.40-1.77) than among those without night shifts. To conclude, this study shows that shift workers with and without night shifts more often have difficulties combining work and life than day workers. Several unsocial working hour characteristics, including long work weeks, evening and night shifts, weekend work, and quick returns, are associated with work-life conflict.

[Night shift work and prolactin as a breast cancer risk factor].

PubMed

Bukowska, Agnieszka; Pepłońska, Beata

2013-01-01

Prolactin - a hormone secreted in a circadian rhythm acts as a regulator of growth and development of the mammary glands. It has been observed that working at night increases breast cancer risk in women. Night shift work, probably carcinogenic to humans (Group 2A IARC), can disrupt a circadian rhythm, and thus potentially alter the rhythm of prolactin secretion. The aim of our work was to review epidemiological evidence on the association between prolactin and the risk of breast cancer and the influence of work at night on prolactin secretion. Search was done in the Medline database by keywords (shift work, work at night, risk of breast cancer and prolactin). 'The increased proliferation of breast cells activated by prolactin can promote the development of cancer. The results of the largest epidemiological prospective studies suggest the association between prolactin levels and the risk of breast cancer in women. So far, only seven studies have investigated the association between work at night and prolactin secretion. In three studies lower concentrations of prolactin have been observed in night shift workers. No relationship between the night shift work duration and prolactin level in women have been reported. Night shift work can modify the profile of prolactin secretion in night workers, probably decreasing the secretion of this hormone at night. It is therefore unlikely that prolactin plays an important role in the development of breast cancer in women working at night. This conclusion is based on the results of a few epidemiological studies.

[Night work, shift work: Breast cancer risk factor?].

PubMed

Benabu, J-C; Stoll, F; Gonzalez, M; Mathelin, C

2015-12-01

The aim of this review was to determine the link between night/shift work and breast cancer. The analysed articles were taken from the PUBMED database between 1996 and 2015. The keywords used were "breast cancer risk", "night work" and "shift work". In total, 25 articles were selected. Night/shift workers are more at risk to develop a breast cancer (relative risk (RR) between 1.09; 95% CI: 1.02-1.20 and 1.48; 95% CI: 1.36-1.61 in the meta-analyses). However, this risk is not found by some cohort and case-control studies. The circadian rhythm disruption, responsible of disorderliness of melatonin secretion, could be one of the mechanisms involved in the increase of that risk. Hormonal status of night/shift workers, their geographic origin, their lifestyle and their vitamin D deficiency appear as other mechanisms potentially responsible for increased risk of cancer in this professional population. Moreover, a dose-effect connection may exist, with an increase of the risk with the number of years of night/shift work. Night/shift work is associated with a moderate increased risk of breast cancer, especially among women who worked over 20 years. Recommendations concerning the breast monitoring in this population could be diffused. The benefit of melatonin supplementation remains to be assessed. Copyright © 2015. Published by Elsevier SAS.

Promoting personal safety of building service workers: issues and challenges.

PubMed

Chen, Shelley I; Skillen, D Lynn

2006-06-01

This exploratory, descriptive study conducted at a large western Canadian university solicited perceptions of personal safety among building service workers who perform night shift work alone. Ten semi-structured interviews were conducted at approximately 10:00 p.m. or 7:00 a.m with a convenience sample of night building service workers in private or semi-private locations on the university campus. Transcribed interview data were subjected to inductive content analysis using descriptive, interpretive, and pattern coding (Miles & Huberman, 1994). Results suggest that building service night shift workers are exposed to personal safety hazards in their physical and psychosocial work environments. In addition, culturally and linguistically appropriate delivery of safety training and education about policies and procedures is required for culturally diverse building service workers. Promotion of personal safety in this heterogeneous worker population requires due diligence, assessment, and advocacy.

Relationship between shift work schedule and self-reported sleep quality in Chinese employees.

PubMed

Ma, Yifei; Wei, Fu; Nie, Guanghui; Zhang, Li'e; Qin, Jian; Peng, Suwan; Xiong, Feng; Zhang, Zhiyong; Yang, Xiaobo; Peng, Xiaowu; Wang, Mingjun; Zou, Yunfeng

2018-02-01

Few studies have reported on the effects of fixed and rotating shift systems on the prevalence of sleep disturbance. Thus, in this study, the relationships between different work schedules and sleep disturbance in Chinese workers were investigated. A total of 2180 workers aged 19-65 years responded to the self-report questionnaire on shift work schedule (fixed day-shift, fixed night-shift, two-shift or three-shift system), working hours a day, and working days a week, physical effort, subjective sleep quality and subjective mental state. It was found that the rotating shift workers, namely, two- and three-shift workers, exhibited higher risks of sleep disturbance than with the fixed day-shift workers did (OR 1.37; 95% CI 1.07to 1.74; and OR 2.19; 95% CI 1.52 to 3.15, respectively). The risk was particularly high among two- or three-shift workers who worked more than 8 hours a day or more than 5 days a week and among three-shift workers who reported both light and heavy physical effort at work. Moreover, the two- and three-shift workers (rotating shift workers) suffered from poorer sleep quality than the fixed night shift workers did (OR 1.84; 95% CI 1.01 to 3.32; and OR 2.94; 95% CI 1.53 to 5.64, respectively). Consequently, rotating shift work (two- and three-shift work) is a risk factor for sleep disturbance, and the fixed work rhythm may contribute to the quality of sleep.

Using blue-green light at night and blue-blockers during the day to improves adaptation to night work: a pilot study.

PubMed

Sasseville, Alexandre; Hébert, Marc

2010-10-01

Bright light at night paired with darkness during the day seem to facilitate adaptation to night work. Considering the biological clock sensitive to short wavelengths, we investigated the possibility of adaptation in shift workers exposed to blue-green light at night, combined with using blue-blockers during the day. Four sawmill shift workers were evaluated during two weeks of night shifts (control and experimental) and one week of day shifts. Throughout the experimental week, ambient light (approximately 130 lx) was supplemented with blue-green light (200 lx) from 00:00 h to: 05:00 h on Monday and Tuesday, 06:00 h on Wednesday and 07:00 h on Thursday. Blue-blockers had to be worn outside from the end of the night shift until 16:00 h. For circadian assessment, salivary melatonin profiles were obtained between 00:00 h and 08:00 h, before and after 4 experimental night shifts. Sleep was continuously monitored with actigraphy and subjective vigilance was measured at the beginning, the middle and the end of each night and day shifts. The error percentage in wood board classification was used as an index of performance. Through experimental week, melatonin profiles of 3 participants have shifted by at least 2 hours. Improvements were observed in sleep parameters and subjective vigilance from the third night (Wednesday) as performance increased on the fourth night (Thursday) from 5.14% to 1.36% of errors (p=0.04). Strategic exposure to short wavelengths at night, and/or daytime use of blue-blocker glasses, seemed to improve sleep, vigilance and performance. Copyright © 2010 Elsevier Inc. All rights reserved.

[Comparative study of sleep patterns in nurses working day and night shifts].

PubMed

De Martino, Milva Maria Figueiredo

2002-08-01

To compare sleep patterns in nurses working day and night shifts in a hospital in Campinas (SP), Brazil. Fifty-nine nurses between 23 and 59 years of age participated in the study. For day shift workers, the pattern of nocturnal sleep was examined; for night shift workers, nocturnal and diurnal sleep patterns were examined. During 1 week, participants filled out a sleep diary right after waking up. The following items were assessed: time going to bed, falling asleep, and waking up; sleep latency; duration in hours of nocturnal and diurnal sleep; naps; quality of sleep; mode of waking up; and comparison between the sleep recorded in the diary with the usual sleep. Personal and professional information was also collected. Day shift workers went to bed at 23h36min, and night workers at 23h52min (P > 0.05). The nurses working a day schedule woke up earlier (7h3min) than those working a night schedule when they slept at night (8h30min) (P

Relationship between napping during night shift work and household obligations of female nursing personnel.

PubMed

Silva-Costa, Aline; Fischer, Frida Marina; Griep, Rosane Harter; Rotenberg, Lúcia

2013-01-01

Night shift employment involves displacing sleep to the daytime. For female workers, the opportunity for daytime sleep is influenced by routine housework demands, which aggravates sleep deprivation. Allowing naps to be taken during the night shift of work is a frequent practice at some hospitals and can help reduce the effects of sleep deprivation. We hypothesize that an association between domestic work and the length of naps during night work exists for nursing professionals. To test this hypothesis, two cross-sectional studies were conducted in two different hospitals. In Study 1, female workers answered questionnaires regarding sleeping habits, professional work, and housework demands. In Study 2, data regarding napping during shifts was obtained by actigraphy, a noninvasive method of monitoring the human sleep-wake cycle. The demand for the performance of housework was measured by (i) domestic work hours (total time spent performing domestic work per week), and (ii) domestic workload, which considers the degree of sharing domestic tasks and the number of people living at home. The populations from the two studies were subdivided into groups, based on the duration of napping at work. Data on naps were analyzed according to domestic demands, using the Mann-Whitney and Chi-squared tests. Among the two study populations (Studies 1 and 2), those in Study 2 were older, had shorter professional weekly work hours, worked more night shifts, and dedicated more time to housework. significant associations were only found in Study 2, where greater time napping at work was associated with both greater time spent doing housework and greater domestic workload. The known benefits of napping during night shifts seem to be especially relevant for female workers who are more sleep-deprived from working more night shifts and who have higher demands for housework.

Obesity and high blood pressure of 12-hour night shift female clean-room workers.

PubMed

Chen, Jong-Dar; Lin, Yu-Cheng; Hsiao, Shu-Tin

2010-01-01

The 12 h shift schedule is widely used in clean rooms for electronic semiconductor production in Taiwan. This study investigated the associations of obesity and metabolic syndrome (MetS) components among women working in a semiconductor manufacturing factory in North Taiwan. Workers were divided into four groups according to their work schedules and duties (i.e., office workers, day workers, fixed 12 h day shift, and fixed 12 h night shiftworkers). The subjects comprised 1838 women who voluntarily attended a health examination between August 2006 and November 2006. Their mean (+/-SD) age was 33.6 (+/-7.1) yrs and their mean duration of work was 7.4 (+/-5.2) yrs. Each subject's health-related behaviors, body mass index, and MetS components were measured and analyzed using multivariate logistic regression. Obesity and MetS were defined according to World Health Organization criteria for Asian populations and the National Cholesterol Educational Program and Adult Treatment Panel III Guidelines, respectively. The results showed that women working in the clean room on fixed 12 h night shifts had significantly elevated odds ratios for obesity (OR, 2.7; 95% CI, 1.6-4.5), central obesity (OR, 2.9; 95% CI, 1.7-5.1), and high blood pressure (OR, 2.3; 95% CI, 1.2-4.4) compared to female office workers; these results persisted after adjusting for age, smoking, drinking, education, and duration of work. We did not find any significant differences in triglyceride and high-density lipoprotein cholesterol among women working different schedules. We conclude that working fixed 12 h night shifts was associated with an increased odds ratio for obesity, central obesity, and high blood pressure among clean-room women workers. Weight reduction and blood pressure control programs should be implemented in the workplace for women working fixed 12 h night shifts.

Heart rate variability changes in business process outsourcing employees working in shifts.

PubMed

Kunikullaya, Kirthana U; Kirthi, Suresh K; Venkatesh, D; Goturu, Jaisri

2010-10-31

Irregular and poor quality sleep is common in business process outsourcing (BPO) employees due to continuous shift working. The influence of this on the cardiac autonomic activity was investigated by the spectral analysis of heart rate variability (HRV). 36 night shift BPO employees (working from 22:00 to 06:00h) and 36 age and sex matched day shift BPO employees (working from 08:00 to 16:00h) were recruited for the study. Five minute electrocardiogram (ECG) was recorded in all the subjects. Heart rate variability was analyzed by fast Fourier transformation using RMS Vagus HRV software. The results were analyzed using Mann Whitney U test, Student t-test, Wilcoxon signed rank test and were expressed as mean ± SD. Sleepiness was significantly higher among night shift workers as measured by Epworth Sleepiness Scale (p<0.001). Night shift BPO employees were found to have a trend towards lower values of vagal parameters - HF power (ms(2)), and higher values of sympathovagal parameters like LF Power (ms(2)) and the LF/HF power (%) suggesting decreased vagal activity and sympathetic over activity, when compared to day shift employees. However, HRV parameters did not vary significantly between the day shift employees and night shift workers baseline values, and also within the night shift group. Night shift working increased the heart rate and shifted the sympathovagal balance towards sympathetic dominance and decreased vagal parameters of HRV. This is an indicator of unfavorable change in the myocardial system, and thus shows increased risk of cardiovascular disease among the night shift employees.

SHIFT WORK AND BREAST CANCER AMONG WOMEN TEXTILE WORKERS IN SHANGHAI, CHINA

PubMed Central

Li, Wenjin; Ray, Roberta M.; Thomas, David B.; Davis, Scott; Yost, Michael; Breslow, Norman; Gao, Dao Li; Fitzgibbons, E. Dawn; Camp, Janice E.; Wong, Eva; Wernli, Karen J.; Checkoway, Harvey

2014-01-01

PURPOSE Although night shift work has been associated with elevated risk of breast cancer in numerous epidemiologic studies, evidence is not consistent. We conducted a nested case-cohort study to investigate a possible association between shift work including a night shift and risk of breast cancer within a large cohort of women textile workers in Shanghai, China. METHODS The study included 1709 incident breast cancer cases and 4780 non-cases. Data on historical shift-work schedules were collected by categorized jobs from the factories where the study subjects had worked, and then were linked to the complete work histories of each subject. No jobs in the factories involved exclusively night shift work. Therefore, night shift was evaluated as part of a rotating shift work pattern. Hazard ratios and 95% confidence intervals were calculated using Cox proportional hazards modeling adapted for the case-cohort design for years of night-shift work and the total number of nights worked. Additionally, analyses were repeated with exposures lagged by 10 and 20 years. RESULTS We observed no associations with either years of night-shift work, or number of nights worked during the entire employment period, irrespective of lag intervals. Findings from the age-stratified analyses were very similar to those observed for the entire study population. CONCLUSIONS The findings from this study provide no evidence to support the hypothesis that shift work increases breast cancer risk. The positive association between shift work and breast cancer observed in Western populations, but not observed in this and other studies of the Chinese population, suggest that the effect of shift work on breast cancer risk may be different in Asian and Caucasian women. PMID:25421377

Shift work and breast cancer among women textile workers in Shanghai, China.

PubMed

Li, Wenjin; Ray, Roberta M; Thomas, David B; Davis, Scott; Yost, Michael; Breslow, Norman; Gao, Dao Li; Fitzgibbons, E Dawn; Camp, Janice E; Wong, Eva; Wernli, Karen J; Checkoway, Harvey

2015-01-01

Although night-shift work has been associated with elevated risk of breast cancer in numerous epidemiologic studies, evidence is not consistent. We conducted a nested case-cohort study to investigate a possible association between shift work including a night shift and risk of breast cancer within a large cohort of women textile workers in Shanghai, China. The study included 1,709 incident breast cancer cases and 4,780 non-cases. Data on historical shift work schedules were collected by categorized jobs from the factories, where the study subjects had worked, and then were linked to the complete work histories of each subject. No jobs in the factories involved exclusively night-shift work. Therefore, night shift was evaluated as part of a rotating shift work pattern. Hazard ratios and 95 % confidence intervals were calculated using Cox proportional hazards modeling adapted for the case-cohort design for years of night-shift work and the total number of nights worked. Additionally, analyses were repeated with exposures lagged by 10 and 20 years. We observed no associations with either years of night-shift work or number of nights worked during the entire employment period, irrespective of lag intervals. Findings from the age-stratified analyses were very similar to those observed for the entire study population. The findings from this study provide no evidence to support the hypothesis that shift work increases breast cancer risk. The positive association between shift work and breast cancer observed in Western populations, but not observed in this and other studies of the Chinese population, suggests that the effect of shift work on breast cancer risk may be different in Asian and Caucasian women.

Meta-analysis on shift work and risks of specific obesity types.

PubMed

Sun, M; Feng, W; Wang, F; Li, P; Li, Z; Li, M; Tse, G; Vlaanderen, J; Vermeulen, R; Tse, L A

2018-01-01

This systematic review and meta-analysis evaluated the associations between shift work patterns and risks of specific types of obesity. PubMed was searched until March 2017 for observational studies that examined the relationships between shift work patterns and obesity. Odds ratio for obesity was extracted using a fixed-effects or random-effects model. Subgroup meta-analyses were carried out for study design, specific obesity types and characteristics of shift work pattern. A total of 28 studies were included in this meta-analysis. The overall odds ratio of night shift work was 1.23 (95% confidence interval = 1.17-1.29) for risk of obesity/overweight. Cross-sectional studies showed a higher risk of 1.26 than those with the cohort design (risk ratio = 1.10). Shift workers had a higher frequency of developing abdominal obesity (odds ratio = 1.35) than other obesity types. Permanent night workers demonstrated a 29% higher risk than rotating shift workers (odds ratio 1.43 vs. 1.14). This meta-analysis confirmed the risks of night shift work for the development of overweight and obesity with a potential gradient association suggested, especially for abdominal obesity. Modification of working schedules is recommended, particularly for prolonged permanent night work. More accurate and detailed measurements on shift work patterns should be conducted in future research. © 2017 World Obesity Federation.

Some health effects of aircraft noise with special reference to shift work.

PubMed

Rizk, Sanaa A M; Sharaf, Nevin E; Mahdy-Abdallah, Heba; ElGelil, Khalid S Abd

2016-06-01

Aircraft noise is an environmental stressor. A positive relationship exists between noise and high blood pressure. Shift work is an additional hazardous working condition with negative effect on the behavior attitude of workers. This study aimed at investigating some health hazards for shift work on workers at Cairo International Airport (CIA), Egypt, as a strategic work place, with more than one stressor. Assessment of noise effects were carried out in four working sites at the airport besides control sites. The average noise level in the exposure sites was 106.5 dB compared with 54 dB at the control sites. The study comprised a group of 200 male workers exposed to aircraft noise and 110 male workers not exposed to noise as control group. All workers had full general medical examination after filling specially formulated questionnaire. Hearing impairment, raised blood pressure, headaches, disturbed sleep, and symptoms of anxiety were more prominent among the exposed workers than the control. Symptoms of upper respiratory tract were reported among night shifters of both groups with high tendency for smoking. Thus, night-shift workers at CIA work under more than one stressor. Hypertension and smoking might act as intermediate factors on the causal pathway of complaints, making aircraft noise and night shift acting as two synergistic stressors. Airport workers are in need for aggressive hearing conservation programs. Organization of the working hours schedule is mandatory to avoid excessive noise exposure. © The Author(s) 2014.

High risk of near-crash driving events following night-shift work

PubMed Central

Lee, Michael L.; Howard, Mark E.; Horrey, William J.; Liang, Yulan; Anderson, Clare; Shreeve, Michael S.; O’Brien, Conor S.; Czeisler, Charles A.

2016-01-01

Night-shift workers are at high risk of drowsiness-related motor vehicle crashes as a result of circadian disruption and sleep restriction. However, the impact of actual night-shift work on measures of drowsiness and driving performance while operating a real motor vehicle remains unknown. Sixteen night-shift workers completed two 2-h daytime driving sessions on a closed driving track at the Liberty Mutual Research Institute for Safety: (i) a postsleep baseline driving session after an average of 7.6 ± 2.4 h sleep the previous night with no night-shift work, and (ii) a postnight-shift driving session following night-shift work. Physiological measures of drowsiness were collected, including infrared reflectance oculography, electroencephalography, and electrooculography. Driving performance measures included lane excursions, near-crash events, and drives terminated because of failure to maintain control of the vehicle. Eleven near-crashes occurred in 6 of 16 postnight-shift drives (37.5%), and 7 of 16 postnight-shift drives (43.8%) were terminated early for safety reasons, compared with zero near-crashes or early drive terminations during 16 postsleep drives (Fishers exact: P = 0.0088 and P = 0.0034, respectively). Participants had a significantly higher rate of lane excursions, average Johns Drowsiness Scale, blink duration, and number of slow eye movements during postnight-shift drives compared with postsleep drives (3.09/min vs. 1.49/min; 1.71 vs. 0.97; 125 ms vs. 100 ms; 35.8 vs. 19.1; respectively, P < 0.05 for all). Night-shift work increases driver drowsiness, degrading driving performance and increasing the risk of near-crash drive events. With more than 9.5 million Americans working overnight or rotating shifts and one-third of United States commutes exceeding 30 min, these results have implications for traffic and occupational safety. PMID:26699470

High risk of near-crash driving events following night-shift work.

PubMed

Lee, Michael L; Howard, Mark E; Horrey, William J; Liang, Yulan; Anderson, Clare; Shreeve, Michael S; O'Brien, Conor S; Czeisler, Charles A

2016-01-05

Night-shift workers are at high risk of drowsiness-related motor vehicle crashes as a result of circadian disruption and sleep restriction. However, the impact of actual night-shift work on measures of drowsiness and driving performance while operating a real motor vehicle remains unknown. Sixteen night-shift workers completed two 2-h daytime driving sessions on a closed driving track at the Liberty Mutual Research Institute for Safety: (i) a postsleep baseline driving session after an average of 7.6 ± 2.4 h sleep the previous night with no night-shift work, and (ii) a postnight-shift driving session following night-shift work. Physiological measures of drowsiness were collected, including infrared reflectance oculography, electroencephalography, and electrooculography. Driving performance measures included lane excursions, near-crash events, and drives terminated because of failure to maintain control of the vehicle. Eleven near-crashes occurred in 6 of 16 postnight-shift drives (37.5%), and 7 of 16 postnight-shift drives (43.8%) were terminated early for safety reasons, compared with zero near-crashes or early drive terminations during 16 postsleep drives (Fishers exact: P = 0.0088 and P = 0.0034, respectively). Participants had a significantly higher rate of lane excursions, average Johns Drowsiness Scale, blink duration, and number of slow eye movements during postnight-shift drives compared with postsleep drives (3.09/min vs. 1.49/min; 1.71 vs. 0.97; 125 ms vs. 100 ms; 35.8 vs. 19.1; respectively, P < 0.05 for all). Night-shift work increases driver drowsiness, degrading driving performance and increasing the risk of near-crash drive events. With more than 9.5 million Americans working overnight or rotating shifts and one-third of United States commutes exceeding 30 min, these results have implications for traffic and occupational safety.

A Rodent Model of Night-Shift Work Induces Short-Term and Enduring Sleep and Electroencephalographic Disturbances.

PubMed

Grønli, Janne; Meerlo, Peter; Pedersen, Torhild T; Pallesen, Ståle; Skrede, Silje; Marti, Andrea R; Wisor, Jonathan P; Murison, Robert; Henriksen, Tone E G; Rempe, Michael J; Mrdalj, Jelena

2017-02-01

Millions of people worldwide are working at times that overlap with the normal time for sleep. Sleep problems related to the work schedule may mediate the well-established relationship between shift work and increased risk for disease, occupational errors and accidents. Yet, our understanding of causality and the underlying mechanisms that explain this relationship is limited. We aimed to assess the consequences of night-shift work for sleep and to examine whether night-shift work-induced sleep disturbances may yield electrophysiological markers of impaired maintenance of the waking brain state. An experimental model developed in rats simulated a 4-day protocol of night-work in humans. Two groups of rats underwent 8-h sessions of enforced ambulation, either at the circadian time when the animal was physiologically primed for wakefulness (active-workers, mimicking day-shift) or for sleep (rest-workers, mimicking night-shift). The 4-day rest-work schedule induced a pronounced redistribution of sleep to the endogenous active phase. Rest-work also led to higher electroencephalogram (EEG) slow-wave (1-4 Hz) energy in quiet wakefulness during work-sessions, suggesting a degraded waking state. After the daily work-sessions, being in their endogenous active phase, rest-workers slept less and had higher gamma (80-90 Hz) activity during wake than active-workers. Finally, rest-work induced an enduring shift in the main sleep period and attenuated the accumulation of slow-wave energy during NREM sleep. A comparison of recovery data from 12:12 LD and constant dark conditions suggests that reduced time in NREM sleep throughout the recorded 7-day recovery phase induced by rest-work may be modulated by circadian factors. Our data in rats show that enforced night-work-like activity during the normal resting phase has pronounced acute and persistent effects on sleep and waking behavior. The study also underscores the potential importance of animal models for future studies on the health consequences of night-shift work and the mechanisms underlying increased risk for diseases.

Temporal dynamics of circadian phase shifting response to consecutive night shifts in healthcare workers: role of light-dark exposure.

PubMed

Stone, Julia E; Sletten, Tracey L; Magee, Michelle; Ganesan, Saranea; Mulhall, Megan D; Collins, Allison; Howard, Mark; Lockley, Steven W; Rajaratnam, Shantha M W

2018-06-01

Shift work is highly prevalent and is associated with significant adverse health impacts. There is substantial inter-individual variability in the way the circadian clock responds to changing shift cycles. The mechanisms underlying this variability are not well understood. We tested the hypothesis that light-dark exposure is a significant contributor to this variability; when combined with diurnal preference, the relative timing of light exposure accounted for 71% of individual variability in circadian phase response to night shift work. These results will drive development of personalised approaches to manage circadian disruption among shift workers and other vulnerable populations to potentially reduce the increased risk of disease in these populations. Night shift workers show highly variable rates of circadian adaptation. This study examined the relationship between light exposure patterns and the magnitude of circadian phase resetting in response to night shift work. In 21 participants (nursing and medical staff in an intensive care unit) circadian phase was measured using 6-sulphatoxymelatonin at baseline (day/evening shifts or days off) and after 3-4 consecutive night shifts. Daily light exposure was examined relative to individual circadian phase to quantify light intensity in the phase delay and phase advance portions of the light phase response curve (PRC). There was substantial inter-individual variability in the direction and magnitude of phase shift after three or four consecutive night shifts (mean phase delay -1:08 ± 1:31 h; range -3:43 h delay to +3:07 h phase advance). The relative difference in the distribution of light relative to the PRC combined with diurnal preference accounted for 71% of the variability in phase shift. Regression analysis incorporating these factors estimated phase shift to within ±60 min in 85% of participants. No participants met criteria for partial adaptation to night work after three or four consecutive night shifts. Our findings provide evidence that the phase resetting that does occur is based on individual light exposure patterns relative to an individual's baseline circadian phase. Thus, a 'one size fits all' approach to promoting adaptation to shift work using light therapy, implemented without knowledge of circadian phase, may not be efficacious for all individuals. © 2018 Monash University. The Journal of Physiology © 2018 The Physiological Society.

Night Shift Work and Levels of 6-Sulfatoxymelatonin and Cortisol in Men

PubMed Central

Mirick, Dana K.; Bhatti, Parveen; Chen, Chu; Nordt, Frank; Stanczyk, Frank Z.; Davis, Scott

2016-01-01

Background Nightshift work is associated with cancer among men, but the biological mechanism is unclear. We investigated whether male nightshift workers demonstrated changes in levels of melatonin and cortisol, potential biomarkers of cancer risk. Methods Urine was collected from 185 nightshift and 158 dayshift-working male healthcare providers, aged 22-55, throughout work and sleep periods and assayed for 6-sulfatoxymelatonin and cortisol. Morning serum was collected within 90 minutes of completing the night and assayed for cortisol. Results Nightshift workers had significantly lower 6-sulfatoxymelatonin levels during daytime sleep, nighttime work, and nighttime sleep on off-nights (57%, 62% and 40% lower, respectively), relative to the dayshift workers during nighttime sleep (p<0.0001); urinary cortisol in nightshift workers was 16% higher during daytime sleep and 13% lower during nighttime sleep on off-nights (p<0.05). Morning serum cortisol post-work and post-sleep in nightshift workers were 24% and 43% lower, respectively, than post-sleep levels among dayshift workers (p<0.0001). Within-subject comparisons among the nightshift workers revealed significantly lower melatonin levels and significantly higher urinary cortisol levels during daytime sleep and nighttime work, relative to nighttime sleep (p<0.01); morning serum cortisol levels post-work were lower than those post-sleep. Conclusions Nightshift workers have substantially lower 6-sulfatoxymelatonin during night work and daytime sleep, and levels remain low when nightshift workers sleep at night. Chronic reduction in melatonin among nightshift workers may be an important carcinogenic mechanism. Cortisol secretion patterns may be impacted by night shift work, which could affect cancer risk. Impact Shiftwork could be an important risk factor for many types of cancer. PMID:23563887

[Fatigue symptoms and workplace related factors of long-term care workers employed in facilities].

PubMed

Kawamura, Sachiyo; Yamada, Kazuko; Morioka, Ikuharu

2015-01-01

"Regular visiting/on-demand response type long-term care" has recently been established. This will lead to a decrease in the burden on the family, but an increase in the burden of the care personnel who provide this kind of long-term care. The objectives of this study were to clarify the fatigue symptoms of long-term care workers in facilities that provide this kind of long-term care, and examine the related factors in the workplace. An anonymous questionnaire survey was conducted with 96 workers engaged in long-term care in facilities. The questionnaire was composed of cumulative fatigue symptoms index, work situation, supports in the workplace, and the attributes. The subjects were divided into two groups: those who had night shift between PM 6 to AM 8 with or without day shift (night shift group), and those who had only day shift (day shift group). The relationships between the fatigue symptom levels and work situation etc. were compared between the two groups. The night shift group consisted of 47 workers, whose mean age was 42.3 years and whose mean working experience was 6.0 years. The median number of persons they had visited in the previous month was 9. The day shift group consisted of 49 workers, whose mean age was 44.6 years and whose mean working experience was 5.9 years. The median number of persons they visited in the previous month was 9.5. Age and sex distributions showed no difference between the two groups. There was no difference in the work situations and the supports in the workplace, except for working time and the details of care the subjects were providing. The fatigue symptom levels were high in both groups, but in the night shift group the level of physical disorders was higher than in the day shift group. Satisfaction with work, education and training for mental health and consideration for traffic safety when making home visits were negatively related to fatigue symptom levels in both groups. Learning care during the previous year, and the ease of receiving paid holiday were not related to the fatigue symptom levels in the night shift group. This was different in the day shift group. Measures of fatigue symptoms should be performed for both groups. It is desirable that supports, additional to that given in the workplace to the day shift group, be given to the night shift group, and its efficacy be researched.

Effects of Shift and Night Work in the Offshore Petroleum Industry: A Systematic Review

PubMed Central

FOSSUM, Ingrid Nesdal; BJORVATN, Bjørn; WAAGE, Siri; PALLESEN, Ståle

2013-01-01

Shift and night work are associated with several negative outcomes. The aim of this study was to make a systematic review of all studies which examine effects of shift and night work in the offshore petroleum industry, to synthesize the knowledge of how shift work offshore may affect the workers. Searches for studies concerning effects on health, sleep, adaptation, safety, working conditions, family- and social life and turnover were conducted via the databases Web of Knowledge, PsycINFO and PubMed. Search was also conducted through inspection of reference lists of relevant literature. We identified studies describing effects of shift work in terms of sleep, adaptation and re-adaptation of circadian rhythms, health outcomes, safety and accidents, family and social life, and work perceptions. Twenty-nine studies were included. In conclusion, the longitudinal studies were generally consistent in showing that adaptation to night work was complete within one to two weeks of work, while re-adaptation to a daytime schedule was slower. Shift workers reported more sleep problems than day workers. The data regarding mental and physical health, family and social life, and accidents yielded inconsistent results, and were insufficient as a base for drawing general conclusions. More research in the field is warranted. PMID:23803497

Inflammatory Long Pentraxin 3 is Associated with Leukocyte Telomere Length in Night-Shift Workers.

PubMed

Pavanello, Sofia; Stendardo, Mariarita; Mastrangelo, Giuseppe; Bonci, Melissa; Bottazzi, Barbara; Campisi, Manuela; Nardini, Marco; Leone, Roberto; Mantovani, Alberto; Boschetto, Piera

2017-01-01

Aging is an emerging worldwide threat to public health, even in the workplace, as it links with risk of illness and death. Bewildered inflammatory responses and stressful conditions associate with age-related disorders. Additionally, circadian rhythm disruption, a critical health issue in night-shift workers, correlates with premature aging. We investigated the hypothesis of a link between altered inflammatory response, detected by plasmatic long pentraxin 3 (PTX3), and biological aging, measured by leukocyte telomere length (LTL), attrition, and possibly induced by night-shift work. Within the framework of a cross-sectional study, such possible relationships were appraised by simultaneous equation model (SEM) technique among day and night-shift hospital workers. PTX3 levels, modulated by several aging conditions [i.e., body mass index (BMI) (beta = -0.22; p  = 0.022), C-reactive protein (CRP) (beta = -0.07; p  = 0.000), and cardiovascular diseases with hypertension included (CVD) (beta = -0.12; p  = 0.000)], positively associate with LTL (coefficient = 0.15; p  = 0.033). LTL, in turn is reduced by CVD (beta = -0.15; p  = 0.000), binge drinking (beta = -0.10; p  = 0.004), and CRP (beta = -0.05; p  = 0.026). On the other hand, night-shift work, found to be remarkably free from aging risk factors [i.e., age (beta = -0.13; p  = 0.017), BMI (beta = -0.17; p  = 0.030), CVD (beta = -0.14; p  = 0.000), and binge drinking (beta = -0.13; p  = 0.000)], does associate almost significantly with reversed PTX3 (coefficient = -0.09; p  = 0.089) and even with CRP (beta = 0.17; p  = 0.000). In conclusion, the SEM analysis indicates that PTX3 is positively linked to LTL. The finding suggests a possible new role of this long pentraxin that, by orchestrating an efficient governance of inflammatory processes, may protect telomere from attrition, ensuring therefore the genetic stability of cells. The higher CRP levels among night-shift workers suggest that night-shift work is associated with increased systemic inflammation. This would make nocturnal workers more susceptible to premature aging.

Inflammatory Long Pentraxin 3 is Associated with Leukocyte Telomere Length in Night-Shift Workers

PubMed Central

Pavanello, Sofia; Stendardo, Mariarita; Mastrangelo, Giuseppe; Bonci, Melissa; Bottazzi, Barbara; Campisi, Manuela; Nardini, Marco; Leone, Roberto; Mantovani, Alberto; Boschetto, Piera

2017-01-01

Aging is an emerging worldwide threat to public health, even in the workplace, as it links with risk of illness and death. Bewildered inflammatory responses and stressful conditions associate with age-related disorders. Additionally, circadian rhythm disruption, a critical health issue in night-shift workers, correlates with premature aging. We investigated the hypothesis of a link between altered inflammatory response, detected by plasmatic long pentraxin 3 (PTX3), and biological aging, measured by leukocyte telomere length (LTL), attrition, and possibly induced by night-shift work. Within the framework of a cross-sectional study, such possible relationships were appraised by simultaneous equation model (SEM) technique among day and night-shift hospital workers. PTX3 levels, modulated by several aging conditions [i.e., body mass index (BMI) (beta = −0.22; p = 0.022), C-reactive protein (CRP) (beta = −0.07; p = 0.000), and cardiovascular diseases with hypertension included (CVD) (beta = −0.12; p = 0.000)], positively associate with LTL (coefficient = 0.15; p = 0.033). LTL, in turn is reduced by CVD (beta = −0.15; p = 0.000), binge drinking (beta = −0.10; p = 0.004), and CRP (beta = −0.05; p = 0.026). On the other hand, night-shift work, found to be remarkably free from aging risk factors [i.e., age (beta = −0.13; p = 0.017), BMI (beta = −0.17; p = 0.030), CVD (beta = −0.14; p = 0.000), and binge drinking (beta = −0.13; p = 0.000)], does associate almost significantly with reversed PTX3 (coefficient = −0.09; p = 0.089) and even with CRP (beta = 0.17; p = 0.000). In conclusion, the SEM analysis indicates that PTX3 is positively linked to LTL. The finding suggests a possible new role of this long pentraxin that, by orchestrating an efficient governance of inflammatory processes, may protect telomere from attrition, ensuring therefore the genetic stability of cells. The higher CRP levels among night-shift workers suggest that night-shift work is associated with increased systemic inflammation. This would make nocturnal workers more susceptible to premature aging. PMID:28536575

Factors affecting work ability in day and shift-working nurses.

PubMed

Camerino, Donatella; Conway, Paul Maurice; Sartori, Samantha; Campanini, Paolo; Estryn-Béhar, Madeleine; van der Heijden, Beatrice Isabella Johanna Maria; Costa, Giovanni

2008-04-01

Satisfactory work ability is sustained and promoted by good physical and mental health and by favorable working conditions. This study examined whether favorable and rewarding work-related factors increased the work ability among European nurses. The study sample was drawn from the Nurses' Early Exit Study and consisted of 7,516 nursing staff from seven European countries working in state-owned and private hospitals. In all, 10.8% were day, 4.2% were permanent night, 20.9% were shift without night shift, and 64.1% were shift workers with night shifts. Participants were administered a composite questionnaire at baseline (Time 0) and 1 yr later (Time 1). The Work Ability Index (WAI) at Time 1 was used as the outcome measure, while work schedule, sleep, rewards (esteem and career), satisfaction with pay, work involvement and motivation, and satisfaction with working hours at Time 0 were included as potential determinants of work ability. Univariate and multivariate analyses were conducted after adjusting for a number of confounders (i.e., country, age, sex, type of employment, family status, and other job opportunities in the same area). Work schedule was not related to Time 1 changes in WAI. Higher sleep quality and quantity and more favorable psychosocial factors significantly increased work ability levels. Higher sleep quality and quantity did not mediate the effect of work schedule on work ability. No relevant interaction effects on work ability were observed between work schedule and the other factors considered at Time 0. As a whole, sleep and satisfaction with working time were gradually reduced from day work to permanent night work. However, scores on work involvement, motivation, and satisfaction with pay and rewards were the highest in permanent night workers and the lowest in rotating shift workers that included night shifts.

Shift work and the incidence of prostate cancer: a 10-year follow-up of a German population-based cohort study.

PubMed

Behrens, Thomas; Rabstein, Sylvia; Wichert, Katharina; Erbel, Raimund; Eisele, Lewin; Arendt, Marina; Dragano, Nico; Brüning, Thomas; Jöckel, Karl-Heinz

2017-11-01

Objectives We investigated the association of shift and night work with the incidence of prostate cancer using data of the population-based prospective Heinz Nixdorf Recall Study from the highly industrialized Ruhr area in Germany. Methods Participants of the baseline survey were recruited between 2000-2003. A follow-up survey including, a detailed interview on shift and night work, was conducted from 2011-2014. We included 1757 men who did not report a history of prostate cancer at baseline. We assessed shift- and night-work exposure up to time of the baseline interview. Incident prostate cancers were recorded from baseline through September 2014. We calculated hazard ratios (HR) of shift- and night-work exposure using Cox proportional hazards regression with age at event as timescale, adjusting for smoking status, family history of prostate cancer, education (≤13, 14-17, ≥18 years), and equivalent income (low, medium, high). Results We observed a twofold increased HR for prostate cancer among shift and night workers. Ever employment in shift work was associated with HR 2.29, 95% confidence interval (CI) 1.43-3.67 and night work with HR 2.27, 95% CI 1.42-3.64. HR increased steadily with duration of employment in shift or night work. Stratifying analyses by preferred midpoint of sleep, yielded strongly elevated HR among subjects with early sleep preference, although these analyses were limited by small number of cases. Conclusions We identified increased risks for prostate cancer among men with employment in shift or night work. HR were strongly elevated among long-term employed shift workers and men with early preferred midpoint of sleep.

[Shift Work among Men and Women on the Threshold to Higher Working Age - Working Conditions and Health Status].

PubMed

Leser, C; Tisch, A; Tophoven, S

2016-11-01

Background: The number of older employees in shift and night work has increased significantly in recent years. Furthermore, the proportion of women in shift and night work has increased markedly. This is due to the aging workforce and the expansion of shift work in the tertiary sector. Previous research shows that shift work is often associated with health risks. Against this background, the aim of the present study is to examine the situation of working men and women on the threshold to higher working age with regard to the relationship between shift work and physical health. Methods: We employed data from the study "lidA - leben in der Arbeit" German Cohort Study on Work, Age and Health, a survey of the German baby boom cohorts born in 1959 and 1965 (n=5 637). Linear regression models are used to study the effect of shift work - with and without night work - and of further work exposures on the baby boomers' physical health status. The models control for sleep and health-related behaviour and are stratified by gender. Among women, also the scope of work was taken into account. Results: The results show that male shift workers are burdened by their on average lower occupational status and by physical exposure; female shift workers additionally suffer from high personal effort and low rewards and female part-time shift workers also from overcommitment. Conclusion: Working conditions of shift workers are strongly characterised by work stress. In order to preserve aging shift workers' work ability, some organisational measures seem necessary. In this context, occupational safety and health management as well as opportunities for recovery and encouraging leadership should be considered. © Georg Thieme Verlag KG Stuttgart · New York.

Daily rhythm of salivary IL-1ß, cortisol and melatonin in day and night workers.

PubMed

Reinhardt, Érica Lui; Fernandes, Pedro Augusto Carlos Magno; Markus, Regina Pekelmann; Fischer, Frida Marina

2012-01-01

Shiftwork-induced sleep deprivation and circadian disruption probably leads to an increase in the production of cytokines and dysregulation of innate immune system, respectively. This project aims evaluating changes in salivary IL-1 beta, cortisol, and melatonin in night workers. Method. Two day and three night healthy workers participated in this study. Sleep was evaluated by actimetry and activity protocols. Saliva was collected at waking and bedtime the last workday and the following two days-off and was analyzed by ELISA. Results. Neither sleep duration nor efficiency showed any association with salivary IL-1beta. IL-1beta levels were higher at waking than at bedtime during working days for all workers, but only one day and one night-worker maintained this pattern and hormone rhythms during days off. For this night worker, melatonin levels were shifted to daytime. A second one presented clear alterations in IL-1beta and hormone rhythms on days-off. Conclusions. Our preliminary results suggest that night work can disturb the variation pattern of salivary IL-1beta. No association of this variation with sleep was observed. It seems that disruption in hormone rhythms interfere with salivary IL-1beta production. IL- 1beta production pattern seems to be maintained when rhythms are present, in spite of a shift in melatonin secretion.

Effects of Filtering Visual Short Wavelengths During Nocturnal Shiftwork on Sleep and Performance

PubMed Central

Rahman, Shadab A.; Shapiro, Colin M.; Wang, Flora; Ainlay, Hailey; Kazmi, Syeda; Brown, Theodore J.

2013-01-01

Circadian phase resetting is sensitive to visual short wavelengths (450–480 nm). Selectively filtering this range of wavelengths may reduce circadian misalignment and sleep impairment during irregular light-dark schedules associated with shiftwork. We examined the effects of filtering short wavelengths (<480 nm) during night shifts on sleep and performance in nine nurses (five females and four males; mean age ± SD: 31.3 ± 4.6 yrs). Participants were randomized to receive filtered light (intervention) or standard indoor light (baseline) on night shifts. Nighttime sleep after two night shifts and daytime sleep in between two night shifts was assessed by polysomnography (PSG). In addition, salivary melatonin levels and alertness were assessed every 2 h on the first night shift of each study period and on the middle night of a run of three night shifts in each study period. Sleep and performance under baseline and intervention conditions were compared with daytime performance on the seventh day shift, and nighttime sleep following the seventh daytime shift (comparator). On the baseline night PSG, total sleep time (TST) (p < 0.01) and sleep efficiency (p = 0.01) were significantly decreased and intervening wake times (wake after sleep onset [WASO]) (p = 0.04) were significantly increased in relation to the comparator night sleep. In contrast, under intervention, TST was increased by a mean of 40 min compared with baseline, WASO was reduced and sleep efficiency was increased to levels similar to the comparator night. Daytime sleep was significantly impaired under both baseline and intervention conditions. Salivary melatonin levels were significantly higher on the first (p < 0.05) and middle (p < 0.01) night shifts under intervention compared with baseline. Subjective sleepiness increased throughout the night under both conditions (p < 0.01). However, reaction time and throughput on vigilance tests were similar to daytime performance under intervention but impaired under baseline on the first night shift. By the middle night shift, the difference in performance was no longer significant between day shift and either of the two night shift conditions, suggesting some adaptation to the night shift had occurred under baseline conditions. These results suggest that both daytime and nighttime sleep are adversely affected in rotating-shift workers and that filtering short wavelengths may be an approach to reduce sleep disruption and improve performance in rotating-shift workers. (Author correspondence: casper@lunenfeld.ca) PMID:23834705

Shift work and age as interactive predictors of body mass index among offshore workers.

PubMed

Parkes, Katharine R

2002-02-01

This study investigated shift pattern (day shifts versus day-night rotation) and its interactions with age, and with years of shiftwork exposure, as predictors of body mass index (BMI). Survey data were collected from offshore personnel working day shifts (N=787) or day-night shifts (N=787); information was obtained about shift pattern and years of shiftwork exposure, height, weight, demographic factors, and smoking habits. Hierarchical multiple regression was used to test a model in which BMI was predicted by additive and interactive effects of shift pattern, age, and exposure years with control for confounding variables. In a multivariate analysis (controlling for job type, education and smoking), BMI was predicted by the main effects of age and years of shiftwork exposure. Shift pattern was not significant as a main effect, but it interacted significantly with the curvilinear age term and with the linear and curvilinear components of shiftwork exposure. In the day shift group, age but not exposure predicted BMI; the opposite was true of the day-night shift group. The increase in BMI with an increase in age and exposure years was steeper for the day-night shift group than for the day shift group. The significant interaction effects found in this study were consistent with the view that continued exposure to day-night shift work gives rise to increases in BMI, over and above the normative effects of ageing on BMI shown by day-shift workers.

Fixed or Rotating Night Shift Work Undertaken by Women: Implications for Fertility and Miscarriage.

PubMed

Fernandez, Renae C; Marino, Jennifer L; Varcoe, Tamara J; Davis, Scott; Moran, Lisa J; Rumbold, Alice R; Brown, Hannah M; Whitrow, Melissa J; Davies, Michael J; Moore, Vivienne M

2016-03-01

This review summarizes the evidence concerning effects of night shift work on women's reproductive health, specifically difficulty in conceiving and miscarriage. We distinguish between fixed night shift and rotating night shift, as the population subgroups exposed, the social and biological mechanisms, and the magnitude of effects are likely to differ; of note, women working fixed night shift are known to have high tolerance for this schedule. We identified two relevant systematic reviews with meta-analyses and five additional studies. Night shift work may give rise to menstrual cycle disturbances, but effect sizes are imprecise. Endometriosis may be elevated in night shift workers, but evidence is only preliminary. Adequate data are lacking to assess associations between night shift work and infertility or time to pregnancy. The weight of evidence begins to point to working at night, whether in fixed or rotating shifts, as a risk factor for miscarriage. There are many methodological problems with this literature, with substantial variation in the definitions of night shift and schedule types making comparisons between studies difficult and pooling across studies questionable. Nevertheless, there appears to be grounds for caution and counselling where women have concerns about night shift work and their reproductive health. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Quality of life, life satisfaction and happiness in shift- and non-shiftworkers.

PubMed

Kaliterna, Lipovcan L J; Prizmic, Larsen Z; Zganec, Nino

2004-12-01

To investigate the quality of life, life satisfaction, happiness and demands of work in workers with different work schedules. The survey was carried out on professional workers in social care. Some were shiftworkers whose schedule included night shifts (N=311), some were shiftworkers without night shifts (N=207) and some were non-shiftworkers (N=1,210). Surveys were mailed and the response rate was 86%. For the purpose of this study several variables were selected from the Survey: The Quality of Life Profile, which measures importance, satisfaction, control and opportunities in nine domains of life plus measures of happiness, life satisfaction and demands of work. While both groups of shiftworkers, compared to non-shiftworkers, reported needing more physical effort to complete their work, and reported 'being' more physically tired, no differences were found in reports of overall happiness, life satisfaction or total quality of life. However, night-shiftworkers reported greater percentage of time unhappy than the other two groups of workers. In analyses of the quality of life, night-shiftworkers were less satisfied with domains of spiritual 'being' and physical and community 'belonging' than day-shiftworkers and non-shiftworkers. They also reported having fewer opportunities to improve their physical 'being', leisure, and personal growth than the other two groups. Quality of life in specific domains in night-shiftworkers was rated worse than in other groups of workers. Domain-based quality of life assessment gives more information regarding the particular needs of workers than overall or global measures of well-being.

Mechanisms of Breast Cancer in Shift Workers: DNA Methylation in Five Core Circadian Genes in Nurses Working Night Shifts.

PubMed

Samulin Erdem, Johanna; Skare, Øivind; Petersen-Øverleir, Marte; Notø, Heidi Ødegaard; Lie, Jenny-Anne S; Reszka, Edyta; Pepłońska, Beata; Zienolddiny, Shanbeh

2017-01-01

Shift work has been suggested to be associated with breast cancer risk, and circadian disruption in shift workers is hypothesized as one of the mechanisms of increased cancer risk. There is, however, insufficient molecular evidence supporting this hypothesis. Using the quantitative methodology of pyrosequencing, epigenetic changes in 5-methyl cytosine (5mC) in five circadian genes CLOCK , BMAL1 , CRY1, PER1 and PER2 in female nurses working night shift work (278 breast cancer cases, 280 controls) were analyzed. In breast cancer cases, a medium exposure to night work was associated with increased methylation levels of the CLOCK (p=0.050), BMAL1 (p=0.001) and CRY1 (p=0.040) genes, compared with controls. Within the cases, analysis of the effects of shift work on the methylation patterns showed that methylation of CRY1 was lower in those who had worked night shift and had a high exposure (p=0.006) compared with cases that had worked only days. For cases with a medium exposure to night work, an increase in BMAL1 (p=0.003) and PER1 (p=0.035) methylation was observed compared with day working (unexposed) cases. The methylation levels of the five core circadian genes were also analyzed in relation to the estrogen and progesterone receptors status of the tumors in the cases, and no correlations were observed. Furthermore, nineteen polymorphisms in the five circadian genes were assessed for their effects on the methylation levels of the respective genes, but no associations were found. In summary, our data suggest that epigenetic regulation of CLOCK , BMAL1, CRY1 and PER1 may contribute to breast cancer in shift workers.

Mechanisms of Breast Cancer in Shift Workers: DNA Methylation in Five Core Circadian Genes in Nurses Working Night Shifts

PubMed Central

Samulin Erdem, Johanna; Skare, Øivind; Petersen-Øverleir, Marte; Notø, Heidi Ødegaard; Lie, Jenny-Anne S.; Reszka, Edyta; Pepłońska, Beata; Zienolddiny, Shanbeh

2017-01-01

Shift work has been suggested to be associated with breast cancer risk, and circadian disruption in shift workers is hypothesized as one of the mechanisms of increased cancer risk. There is, however, insufficient molecular evidence supporting this hypothesis. Using the quantitative methodology of pyrosequencing, epigenetic changes in 5-methyl cytosine (5mC) in five circadian genes CLOCK, BMAL1, CRY1, PER1 and PER2 in female nurses working night shift work (278 breast cancer cases, 280 controls) were analyzed. In breast cancer cases, a medium exposure to night work was associated with increased methylation levels of the CLOCK (p=0.050), BMAL1 (p=0.001) and CRY1 (p=0.040) genes, compared with controls. Within the cases, analysis of the effects of shift work on the methylation patterns showed that methylation of CRY1 was lower in those who had worked night shift and had a high exposure (p=0.006) compared with cases that had worked only days. For cases with a medium exposure to night work, an increase in BMAL1 (p=0.003) and PER1 (p=0.035) methylation was observed compared with day working (unexposed) cases. The methylation levels of the five core circadian genes were also analyzed in relation to the estrogen and progesterone receptors status of the tumors in the cases, and no correlations were observed. Furthermore, nineteen polymorphisms in the five circadian genes were assessed for their effects on the methylation levels of the respective genes, but no associations were found. In summary, our data suggest that epigenetic regulation of CLOCK, BMAL1, CRY1 and PER1 may contribute to breast cancer in shift workers. PMID:28928877

Impaired alertness and performance driving home from the night shift: a driving simulator study.

PubMed

Akerstedt, Torbjörn; Peters, Björn; Anund, Anna; Kecklund, Göran

2005-03-01

Driving in the early morning is associated with increased accident risk affecting not only professional drivers but also those who commute to work. The present study used a driving simulator to investigate the effects of driving home from a night shift. Ten shift workers participated after a normal night shift and after a normal night sleep. The results showed that driving home from the night shift was associated with an increased number of incidents (two wheels outside the lane marking, from 2.4 to 7.6 times), decreased time to first accident, increased lateral deviation (from 18 to 43 cm), increased eye closure duration (0.102 to 0.143 s), and increased subjective sleepiness. The results indicate severe postnight shift effects on sleepiness and driving performance.

Daytime Sleep Disturbance in Night Shift Work and the Role of PERIOD3.

PubMed

Cheng, Philip; Tallent, Gabriel; Burgess, Helen J; Tran, Kieulinh Michelle; Roth, Thomas; Drake, Christopher L

2018-03-15

Recent evidence indicates that daytime sleep disturbance associated with night shift work may arise from both circadian misalignment and sleep reactivity to stress. This presents an important clinical challenge because there are limited means of predicting and distinguishing between the two mechanisms, and the respective treatments differ categorically; however, there is support that a polymorphism in the PERIOD3 gene ( PER3 ) may indicate differences in vulnerability to daytime sleep disturbance in shift workers. We recruited 30 fixed night shift workers for laboratory assessments of circadian misalignment (dim light melatonin onset), sleep reactivity to stress (Ford Insomnia Response to Stress Test), daytime sleep disturbance (daytime Insomnia Severity Index), and PER3 genotype ( PER3 4/4 , PER3 5 /- ). The two mechanisms for daytime sleep disturbance (circadian misalignment and sleep reactivity to stress) were compared between PER3 genotypes. Disturbed daytime sleep in the PER3 4/4 group was more likely related to sleep reactivity to stress, whereas disturbed sleep in the PER3 5 /- group was more likely related to circadian misalignment. Exploratory analyses also revealed a blunted melatonin amplitude in the PER3 4/4 genotype group. This study provides further evidence for multiple mechanisms (ie, circadian misalignment versus sleep reactivity to stress) associated with daytime sleep disturbances in shift workers. Additionally, it provides the new finding that PER3 genotype may play an important role in individual vulnerability to the different mechanisms of daytime sleep disturbance in night shift workers. © 2018 American Academy of Sleep Medicine.

Does the association of prostate cancer with night-shift work differ according to rotating vs. fixed schedule? A systematic review and meta-analysis.

PubMed

Mancio, Jennifer; Leal, Cátia; Ferreira, Marta; Norton, Pedro; Lunet, Nuno

2018-04-27

Recent studies suggested that the relation between night-shift work and prostate cancer may differ between rotating and fixed schedules. We aimed to quantify the independent association between night-shift work and prostate cancer, for rotating and fixed schedules. We searched MEDLINE for studies assessing the association of night-shift work, by rotating or fixed schedules, with prostate cancer. We computed summary relative risk (RR) estimates with 95% confidence intervals (95% CI) using the inverse variance method and quantified heterogeneity using the I 2 statistic. Meta-regression analysis was used to compare the summary RR estimates for rotating and fixed schedules, while reducing heterogeneity. A total of nine studies assessed the effect of rotating and, in addition, four of them provided the effect of fixed night-shift work, in relation to daytime workers. Rotating night-shift work was associated with a significantly increased risk of prostate cancer (RR = 1.06, 95% CI of 1.01 to 1.12; I 2  = 50%), but not fixed night-shift work (RR of 1.01, 95% CI of 0.81 to 1.26; I 2  = 33%). In meta-regression model including study design, type of population, and control of confounding, the summary RR was 20% higher for rotating vs. fixed schedule, with heterogeneity fully explained by these variables. This is the first meta-analysis suggesting that an increased risk of prostate cancer may be restricted to workers with rotating night shifts. However, the association was weak and additional studies are needed to further clarify this relation before it can be translated into measures for risk reduction in occupational settings.

Does night-shift work induce apnea events in obstructive sleep apnea patients?

PubMed

Laudencka, A; Klawe, J J; Tafil-Klawe, M; Złomańczuk, P

2007-11-01

The aim of the present study was to determine the direct effect of night-work on the occurrence of obstructive apneas during sleep after a night shift in fast-rotating shift workers with sleep-related breathing disorders. Eight obstructive sleep apnea patients were examined with the use of a polysomnograph during sleep under two conditions: after day-shift work and after night-shift work. Both sleep studies were conducted within 2 to 3 weeks of each other. In four of the 8 subjects, during sleep after a night-shift, an increase in apnea/hypopnea index was found. Night work significantly increased several breathing variables: total duration of obstructive apneas during REM sleep, mean duration of obstructive apneas during arousal, and apnea index during arousal. We conclude that in a subpopulation of sleep apnea patients, acute sleep deprivation may worsen obstructive sleep apnea index.

Validity of self-reported exposure to shift work.

PubMed

Härmä, Mikko; Koskinen, Aki; Ropponen, Annina; Puttonen, Sampsa; Karhula, Kati; Vahtera, Jussi; Kivimäki, Mika

2017-03-01

To evaluate the validity of widely used questionnaire items on work schedule using objective registry data as reference. A cohort study of hospital employees who responded to a self-administered questionnaire on work schedule in 2008, 2012 and 2014 and were linked to individual-level pay-roll-based records on work shifts. For predictive validity, leisure-time fatigue was assessed. According to the survey data in 2014 (n=8896), 55% of the day workers had at least 1 year of earlier shift work experience. 8% of the night shift workers changed to day work during the follow-up. Using pay-roll data as reference, questions on 'shift work with night shifts' and 'permanent night work' showed high sensitivity (96% and 90%) and specificity (92% and 97%). Self-reported 'regular day work' showed moderate sensitivity (73%), but high specificity (99%) and 'shift work without night shifts' showed low sensitivity (62%) and moderate specificity (87%). In multivariate logistic regression analysis, the age-adjusted, sex-adjusted and baseline fatigue-adjusted association between 'shift work without night shifts' and leisure-time fatigue was lower for self-reported compared with objective assessment (1.30, 95% CI 0.94 to 1.82, n=1707 vs 1.89, 95% CI 1.06 to 3.39, n=1627). In contrast, shift work with night shifts, compared with permanent day work, was similarly associated with fatigue in the two assessments (2.04, 95% CI 1.62 to 2.57, n=2311 vs 1.82, 95% CI 1.28 to 2.58, n=1804). The validity of self-reported assessment of shift work varies between work schedules. Exposure misclassification in self-reported data may contribute to bias towards the null in shift work without night shifts. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Day and night shift schedules are associated with lower sleep quality in Evening-types.

PubMed

Martin, Jeanne Sophie; Laberge, Luc; Sasseville, Alexandre; Bérubé, Marilie; Alain, Samuel; Houle, Jérôme; Hébert, Marc

2015-06-01

Eveningness has been suggested as a facilitating factor in adaptation to shift work, with several studies reporting evening chronotypes (E-types) as better sleepers when on night shifts. Conversely, eveningness has been associated with more sleep complaints during day shifts. However, sleep during day shifts has received limited attention in previous studies assessing chronotypes in shift workers. Environmental light exposure has also been reported to differ between chronotypes in day workers. Activity is also known to provide temporal input to the circadian clock. Therefore, the aim of this study was to compare objective sleep, light exposure and activity levels between chronotypes, both during the night and day shifts. Thirty-nine patrol police patrol officers working on a fast rotating shift schedule (mean age ± SD: 28.9 ± 3.2 yrs; 28 males) participated in this study. All subjects completed the Morningness-Eveningness Questionnaire (MEQ). Sleep and activity were monitored with actigraphy (Actiwatch-L; Mini-Mitter/Respironics, Bend, OR) for four consecutive night shifts and four consecutive day shifts (night work schedule: 00:00 h-07:00 h; day work schedule: 07:00 h-15:00 h). Sleep and activity parameters were calculated with Actiware software. MEQ scores ranged from 26 to 56; no subject was categorized as Morning-type. E-types (n = 13) showed significantly lower sleep efficiency, longer snooze time and spent more time awake after sleep onset than Intermediate-types (I-types, n = 26) for both the night and day shifts. E-types also exhibited shorter and more numerous sleep bouts. Furthermore, when napping was taken into account, E-types had shorter total sleep duration than I-types during the day shifts. E-types were more active during the first hours of their night shift when compared to I-types. Also, all participants spent more time active and had higher amount of activity per minute during day shifts when compared to night shifts. No difference was found regarding light exposure between chronotypes. In conclusion, sleep parameters revealed poorer sleep quality in E-types for both the night and day shifts. These differences could not be explained by sleep opportunity, light exposure or activity levels. This study challenges the notion that E-types adapt better to night shifts. Further studies must verify whether E-types exhibit lower sleep quality than Morning-types.

Integrated ergonomics approach toward designing night and shift work in developing countries based on experiences in Bali, Indonesia.

PubMed

Manuaba, A

2001-12-01

Recently, the effort in carrying out an integrated ergonomics approach known as "SHIP" (systemic, holistic, interdisciplinary and participatory) approach has been intensively undertaken in Bali with the aim of sustaining improvements being done. The People's Consultative Assembly of the Republic of Indonesia issued for the 1999-2004 period a "SHIP" Act on the Macro Guidelines of Tourism Development in which ergonomics and other factors must be considered comprehensively to attain sustainable development in tourism. Therefore the night and shift work that is recently increasingly applied in the tourism industry must also be designed and organized through this approach. In fact, however, economic factors have still been the predominant reason for workers to accept any type of night and shift work decided by the management, without taking into account possible impacts and consequences. For example, rapid forward rotation schemes seem more adapted to the hotel industry instead of traditional 6-6-6 rotation. Further, inter-city bus drivers are approved to work a 24-hour shift followed by one day off. These drivers often work an additional risky night shift after two consecutive night shifts so as to meet needed expenses for the family. Cultural or religious activities still presented constraints for workers as they carried out subsequently the night work. Therefore, proactive steps should be taken in a timely manner through the integrated SHIP approach in designing night and shift work so as to achieve work schedules compatible with both social life of shiftworkers and business concerns.

Night Shift Work and Its Health Effects on Nurses.

PubMed

Books, Candie; Coody, Leon C; Kauffman, Ryan; Abraham, Sam

The purpose of this research was to study night shift work and its health effects on nurses. This was a quantitative study using descriptive design; it also incorporated three qualitative open-ended questions to complement the study. The data were collected using Survey Monkey, with an Internet-based confidential data collection tool. The population of relevance to this study was nurses employed in hospital settings in the United States. E-mail addresses and Facebook were used to recruit participants. Results indicated that there is an increased risk of sleep deprivation, family stressors, and mood changes because of working the night shift. Rotating shifts were mentioned as a major concern for night shift nurses. Respondents agreed that complaints about fatigue and fatigue-related illnesses in night shift workers were ignored. There was also a general perception among nurses working the night shift that sleep deprivation leads to negative health consequences including obesity; however, they were not as high a concern as rotating shifts or fatigue.

Mechanisms of breast cancer risk in shift workers: association of telomere shortening with the duration and intensity of night work.

PubMed

Samulin Erdem, Johanna; Notø, Heidi Ødegaard; Skare, Øivind; Lie, Jenny-Anne S; Petersen-Øverleir, Marte; Reszka, Edyta; Pepłońska, Beata; Zienolddiny, Shanbeh

2017-08-01

Occupational factors such as shiftwork and especially night work that involves disruption of the circadian rhythm may contribute to increased breast cancer risk. Circadian disruption may also affect telomere length (TL). While short TL generally is associated with increased cancer risk, its association with breast cancer risk is inconclusive. We suggest that working schedules might be an important factor in assessment of effects of TL on breast cancer risk. Moreover, telomere shortening might be a potential mechanism for night work-related breast cancer. In this study, effects of shift work on TL and its association with breast cancer risk were investigated in a nested breast cancer case-control study of Norwegian nurses. TL was assessed by qPCR in DNA from 563 breast cancer patients and 619 controls. Here, we demonstrate that TL is affected by intensive night work schedules, as work with six consecutive night for a period of more than 5 years was associated with decreased telomere lengths (-3.18, 95% CI: -6.46 to -0.58, P = 0.016). Furthermore, telomere shortening is associated with increased breast cancer risk in workers with long periods of consecutive night shifts. Thus, nurses with longer telomere lengths had a lower risk for breast cancer if they had worked more than four (OR: 0.37, 95% CI: 0.16-0.79, P = 0.014) or five (OR: 0.31, 95% CI: 0.10-0.83, P = 0.029) consecutive night shifts for a period of 5 years or more. These data suggest that telomere shortening is associated with the duration and intensity of night work and may be a contributing factor for breast cancer risk among female shift workers. © 2017 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

Short-term effects of night shift work on breast cancer risk: a cohort study of payroll data.

PubMed

Vistisen, Helene Tilma; Garde, Anne Helene; Frydenberg, Morten; Christiansen, Peer; Hansen, Åse Marie; Andersen, Johnni; Bonde, Jens Peter E; Kolstad, Henrik A

2017-01-01

Objectives The objective was to examine if night shift work is a short-term risk factor for breast cancer, including combined estrogen receptor (ER) and human epidermal growth factor 2 (HER2) breast cancer subtypes. Methods The cohort comprised 155 540 public sector female workers in Denmark who were followed from 2007-2012. Day-to-day work-hour information was available from payroll registers and 1245 incident cases of breast cancer were identified in national cancer registries together with receptor subtype information. Results A rate ratio (RR) of 0.90 [95% confidence interval (95% CI) 0.80-1.01] was observed for workers ever working night shifts during the follow-up period compared with workers only working day shifts after adjustment for age, age at first child, parity, family history of breast or ovarian cancer, sex hormones, medications related to alcoholism, family educational level, mammography screening, and other potential confounders. Comparable results were seen for the inception population of employees with first recorded employment after 2007. Modestly increased RR were suggested for breast cancer subtypes characterized by a positive HER2 status irrespective of ER status. Conclusions These findings do not support an overall short-term effect of night shift work on breast cancer risk. Future studies should explore further the impact of HER2 status.

Effects of Accumulating Work Shifts on Performance-Based Fatigue Using Multiple Strength Measurements in Day and Night Shift Nurses and Aides.

PubMed

Thompson, Brennan J; Stock, Matt S; Banuelas, Victoria K

2017-05-01

Objective This study aimed to examine the effects of accumulating nursing work on maximal and rapid strength characteristics in female nurses and compare these effects in day versus night shift workers. Background Nurses exhibit among the highest nonfatal injury rates of all occupations, which may be a consequence of long, cumulative work shift schedules. Fatigue may accumulate across multiple shifts and lead to performance impairments, which in turn may be linked to injury risks. Method Thirty-seven nurses and aides performed isometric strength-based performance testing of three muscle groups, including the knee extensors, knee flexors, and wrist flexors (hand grip), as well as countermovement jumps, at baseline and following exposure to three 12-hour work shifts in a four-day period. Variables included peak torque (PT) and rate of torque development (RTD) from isometric strength testing and jump height and power output. Results The rigorous work period resulted in significant decreases (-7.2% to -19.2%) in a large majority (8/9) of the isometric strength-based measurements. No differences were noted for the day versus night shift workers except for the RTD at 200 millisecond variable, for which the night shift had greater work-induced decreases than the day shift workers. No changes were observed for jump height or power output. Conclusions A compressed nursing work schedule resulted in decreases in strength-based performance abilities, being indicative of performance fatigue. Application Compressed work schedules involving long shifts lead to functional declines in nurse performance capacities that may pose risks for both the nurse and patient quality of care. Fatigue management plans are needed to monitor and regulate increased levels of fatigue.

Bright light exposure at night and light attenuation in the morning improve adaptation of night shift workers.

PubMed

Yoon, In-Young; Jeong, Do-Un; Kwon, Ki-Bum; Kang, Sang-Bum; Song, Byoung-Gun

2002-05-01

With practical applicability in mind, we wanted to observe whether nocturnal alertness, performance, and daytime sleep could be improved by light exposure of tolerable intensity and duration in a real work place. We also evaluated whether attenuating morning light was important in adaptation of real night shift workers. Twelve night shift nurses participated in this study. The study consisted of three different treatment procedures: Room Light (RL), Bright Light (BL), and Bright Light with Sunglasses (BL/S). In RL, room light exposure was given during the night shift and followed by 1 hr exposure to sunlight or 10,000 lux light the next morning (from 08:30 to 09:30). In BL, a 4-hour nocturnal light exposure of 4,000-6,000 lux (from 01:00 to 05:00) was applied and followed by the same morning light exposure as in RL. In BL/S, the same nocturnal light exposure as in BL was done with light attenuation in the morning. Each treatment procedure was continued for 4 days in a repeated measures, cross-over design. Nocturnal alertness was measured by a visual analog scale. Computerized performance tests were done. Daytime sleep was recorded with actigraphy. The most significant overall improvement of sleep was noted in BL/S. BL showed less improvement than BL/S but more than RL. Comparison of nocturnal alertness among the 3 treatments produced similar results: during BL/S, the subjects were most alert, followed by BL and then by RL. Real night shift workers can improve nocturnal alertness and daytime sleep by bright light exposure in their work place. These improvements can be maximized by attenuating morning light on the way home.

Night shift work and breast cancer: a pooled analysis of population-based case-control studies with complete work history.

PubMed

Cordina-Duverger, Emilie; Menegaux, Florence; Popa, Alexandru; Rabstein, Sylvia; Harth, Volker; Pesch, Beate; Brüning, Thomas; Fritschi, Lin; Glass, Deborah C; Heyworth, Jane S; Erren, Thomas C; Castaño-Vinyals, Gemma; Papantoniou, Kyriaki; Espinosa, Ana; Kogevinas, Manolis; Grundy, Anne; Spinelli, John J; Aronson, Kristan J; Guénel, Pascal

2018-04-01

Night shift work has been suspected to increase breast cancer risk but epidemiological studies have been inconsistent due to heterogeneous assessment of exposure to night work. To overcome this limitation, we pooled data of five population-based case-control studies from Australia, Canada, France, Germany, and Spain into a single harmonized dataset using a common definition of night work including 6093 breast cancer cases and 6933 population controls. The odds ratio for breast cancer in women who ever worked at night for at least 3 h between midnight and 5 a.m. as compared to never night workers was 1.12 (95% CI 1.00-1.25). Among pre-menopausal women, this odds ratio was 1.26 [1.06-1.51], increasing to 1.36 [1.07-1.74] for night shifts ≥ 10 h, 1.80 [1.20-2.71] for work ≥ 3 nights/week, and 2.55 [1.03-6.30] for both duration of night work ≥ 10 years and exposure intensity ≥ 3 nights/week. Breast cancer risk in pre-menopausal women was higher in current or recent night workers (OR = 1.41 [1.06-1.88]) than in those who had stopped night work more than 2 years ago. Breast cancer in post-menopausal women was not associated with night work whatever the exposure metric. The increase in risk was restricted to ER+ tumors, particularly those who were both ER+ and HER2+ . These results support the hypothesis that night shift work increases the risk of breast cancer in pre-menopausal women, particularly those with high intensity and long duration of exposure. Risk difference between pre- and post-menopausal women deserves further scrutiny.

Effects of fatigue on immune function in nurses performing shift work.

PubMed

Nagai, Makie; Morikawa, Yuko; Kitaoka, Kazuyo; Nakamura, Koshi; Sakurai, Masaru; Nishijo, Muneko; Hamazaki, Yuko; Maruzeni, Shoko; Nakagawa, Hideaki

2011-01-01

We investigated the effects of fatigue on NK cell function and lymphocyte subpopulations in nurses performing shift work using a longitudinal design. Fifty-seven female nurses engaged in shift work at a hospital in Japan were selected for our study cohort. The hospital used a counterclockwise rotating three-shift system. Night shifts followed day shifts after a seven-hour interval. Immune parameters measured at the beginning of the day shift through to the end of the night shift were compared between two groups stratified by their level of fatigue. Statistical differences were evaluated after adjusting for baseline immune values and other demographic features. Subjective feelings of fatigue increased progressively from the beginning of day shifts to the end of night shifts. From the beginning of day shifts to the end of night shifts, NK cell activity and CD16(+)CD56(+) lymphocytes decreased, while CD3(+) and CD4(+) lymphocytes increased. The group with the greater increase in fatigue showed a larger decrease in NK cell activity and a larger increase in CD4(+)lymphocytes when compared with the group reporting less fatigue. These findings did not change after adjusting for demographic factors and sleep hours. Our data suggest that shift work has deleterious effects on NK cell function and that the effects depend on the degree of fatigue. Proper management of shift work may lessen fatigue in workers and also ameliorate many health problems experienced by shift workers.

Shift Workers: A Descriptive Analysis of Worker Characteristics.

ERIC Educational Resources Information Center

Medley, Carol

National Longitudinal Surveys of Labor Force Experience (NLS) data were used to describe those people who work outside the traditional 9:00 A.M. to 5:00 P.M. work day. Depending on the approximate time of day they worked, respondents were classified into four categories of workers: day, evening, night, and split shift (working hours interrupted by…

A Survey of Fatigue in Selected United States Air Force Shift Worker Populations

DTIC Science & Technology

2006-03-01

34 (Canadian Health Services Research Foundation, 2000, p. 1). To that end, the present study expanded upon an initial USAF assessment of shift worker ...among permanent night workers . Journal of Occupational Health , 43(6), 301-306. Gawron, V. J., French, J., & Funk, D. (2001). An overview of fatigue...HSW-PE-BR-TR-2006-0003 UNITED STATES AIR FORCE 311th Human Systems Wing A Survey of Fatigue in Selected United States Air Force Shift Worker

Shift work is associated with reduced heart rate variability among men but not women.

PubMed

Hulsegge, Gerben; Gupta, Nidhi; Proper, Karin I; van Lobenstein, Natasja; IJzelenberg, Wilhelmina; Hallman, David M; Holtermann, Andreas; van der Beek, Allard J

2018-05-01

Imbalance in the autonomic nervous system due to a disrupted circadian rhythm may be a cause of shift work-related cardiovascular diseases. We aimed to determine the association between shift work and cardiac autonomic activity in blue-collar workers. The study included 665 blue-collar workers aged 18-68 years in different occupations from two Danish cohort studies. Time and frequency domain parameters of heart rate variability (HRV) were measured during sleep using the Actiheart monitor, and used as markers of cardiac autonomic function. Multiple linear regression analyses were used to investigate differences in HRV between day and shift workers. Shift workers had no significantly different HRV parameters than day workers, except for a lower VLF (B: 0.21; 95% CI: -0.36-0.05). The lower VLF was only present among non-night shift workers (p < 0.05) and not among night shift workers (p > 0.05). Results differed significantly by gender (p for interaction < 0.10): among men, shift work was negatively associated with RMSSD (B: -7.83; 95% CI: -14.28-1.38), SDNN (B: -7.0; 95% CI: -12.27-1.78), VLF (B: -0.27; 95% CI: -0.46-0.09) and Total Power (B: -0.61; 95% CI: -1.20-0.03), while among women, shift work was only associated with the LF/HF ratio (B: -0.29; 95% CI: -0.54-0.03). Shift work was particularly associated with lower HRV during sleep among men. This indicates that shift work causes imbalance in the autonomic nervous system among men, which might increase their risk of cardiovascular diseases. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Shift schedule, work-family relationships, marital communication, job satisfaction and health among transport service shift workers.

PubMed

Iskra-Golec, Irena; Smith, Lawrence; Wilczek-Rużyczka, Ewa; Siemiginowska, Patrycja; Wątroba, Joanna

2017-02-21

Existing research has documented that shiftwork consequences may depend on the shift system parameters. Fast rotating systems (1-3 shifts of the same kind in a row) and day work have been found to be less disruptive biologically and socially than slower rotating systems and afternoon and night work. The aim of this study was to compare day workers and shift workers of different systems in terms of rotation speed and shifts worked with regard to work-family and family-work positive and negative spillover, marital communication style, job satisfaction and health. Employees (N = 168) of the maintenance workshops of transportation service working different shift systems (day shift, weekly rotating 2 and 3‑shift system, and fast rotating 3-shift system) participated in the study. They completed the Work- Family Spillover Questionnaire, Marital Communication Questionnaire, Minnesota Job Satisfaction Questionnaire and the Physical Health Questionnaire (a part of the Standard Shiftwork Index). The workers of quicker rotating 3-shift systems reported significantly higher scores of family-to-work facilitation (F(3, 165) = 4.175, p = 0.007) and a higher level of constructive style of marital communication (Engagement F(3, 165) = 2.761, p = 0.044) than the workers of slower rotating 2-shift systems. There were no differences between the groups of workers with regard to health and job satisfaction. A higher level of work-family facilitation and a more constructive style of marital communication were found among the workers of faster rotating 3-shift system when compared to the workers of a slower rotating 2-shift system (afternoon, night). This may indicate that the fast rotating shift system in contrary to the slower rotating one is more friendly for the work and family domains and for the relationship between them. Int J Occup Med Environ Health 2017;30(1):121-131. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Evaluation of the impact of shiftwork and chronotype on the workers of the imprint and cutting/welding sectors of a flexible packaging manufacturer.

PubMed

de M Guimarães, L B; Pessa, S L R; Biguelini, C

2012-01-01

This article presents a study on the impact of shiftwork and chronotype on the perception of the work conditions, workload and adjustment to shiftwork by the workers of two sectors of a flexible packaging manufacturer, which operates in three fixed shifts. The workers are allocated in one of the shifts (morning, evening and night shifts) without evaluation of their chronotype and/or social needs. The workers' evaluation of the shift system and their work show that they prefer a fixed shift and to work in a shift compatible with their chronotype. The workers with chonotype uncompatible with the shift time tend to be less satisfied with the work conditions and content and feel more discomfort/pain.

Shift work and hypertension: Prevalence and analysis of disease pathways in a German car manufacturing company.

PubMed

Ohlander, Johan; Keskin, Mekail-Cem; Stork, Joachim; Radon, Katja

2015-05-01

Hypertension and cardiovascular disease (CVD) may share a similar pathophysiology. Despite shift workers' CVD excess risk, studies on shift work and hypertension are inconclusive. Blood pressure and shift status for 25,343 autoworkers were obtained from medical check-ups and company registers. Cross-sectional associations modeling the total effect from shift work (day shifts, shift work without nights, rotating shift work with nights, and night shifts) on hypertension were assessed. By sequential adjustments, the influence of behavioral, psychosocial, and physiological factors on the total effect was examined, with subsequent mediation and moderation analyses. Adjusted for confounders, shift work without nights (vs. day shifts) was significantly associated with hypertension (OR 1.15, 95%CI 1.02-1.30). The total effect was mediated by BMI, physical inactivity, and sleep disorders. No moderation of the total effect by behaviors was found. The association between shift work and hypertension seems mainly attributable to behavioral mechanisms. © 2015 Wiley Periodicals, Inc.

Predictive factors of life quality among packaging workers in Taiwan.

PubMed

Yang, Shang-Yu; Hsu, Der-Jen; Yen, Chun-Ming; Chang, Jer-Hao

2018-05-16

The semiconductor plants on the top of high-tech industrial chain hire many packaging workers to carry out miscellaneous packing tasks for various product orders from different companies and countries. Under tremendous workload the quality of life (QoL) of such packaging workers need to be concerned. The aim of this study was to explore factors influencing their QoL. This study recruited 247 packing workers (162 male and 85 female; mean age: 35.6 years old) in 2015 and 2016 from a semiconductor plant in Taiwan by convenience sampling. The questionnaire comprised four parts: demographics, the World Health Organization Quality of Life (WHOQOL-BREF), an occupational burnout inventory and the Nordic Musculoskeletal Questionnaire. The four domains of the WHOQOL-BREF were defined as outcome variables. Predictive factors included gender (reference: male), age (reference: ≤ 35), BMI (reference: ≤ 25), educational level (reference: below university), marital/partner status (reference: married/cohabiting), years of work (reference: ≤ 5), work shift (reference: day shift), personal burnout, work-related burnout, over-commitment to work and the number of body parts with discomfort (0-9). The findings showed that physical QoL was negatively correlated with night -shift work, personal burnout, and number of body parts with discomfort. Psychological QoL was negatively correlated with night shift work and personal burnout. Environment QoL was negatively correlated with being male, night shift work and personal burnout. The results showed that the QoL among the packaging workers could be improved by reducing musculoskeletal discomfort, personal burnout and by improving work schedules.

Who is sleepier on the night shift? The influence of bio-psycho-social factors on subjective sleepiness of female nurses during the night shift.

PubMed

Zion, Nataly; Drach-Zahavy, Anat; Shochat, Tamar

2018-07-01

Sleepiness is a common complaint during the night shift and may impair performance. The current study aims to identify bio-psycho-social factors associated with subjective sleepiness during the night shift. Ninety-two female nurses working rotating shifts completed a sociodemographic questionnaire, the Munich ChronoType Questionaire for shift workers, the Pittsburg Sleep Quality Index, and the Pre-sleep Arousal Scale. Subjective sleepiness was measured hourly during two night shifts using the Karolinska Sleepiness Scale, and activity monitors assessed sleep duration 24-h before each shift. Findings showed that increased sleepiness was associated with increased age in nurses with early chronotypes and with more children. High cognitive pre-sleep arousal, but not sleep, was associated with increased sleepiness, especially in late chronotypes. The impact of bio-psycho-social factors on night shift sleepiness is complex, and depends on mutual interactions between these factors. Nurses most prone to increased sleepiness must develop personal strategies for maintaining vigilance on the night shift. Practitioner Summary: This study aims to identify bio-psycho-social factors associated with subjective sleepiness of female nurses during the night shift. Increasing sleepiness was associated with increased age in nurses with early chronotypes and with more children. Increased cognitive pre-sleep arousal, but not sleep, was associated with increased sleepiness, especially in late chronotypes.

Shift work and its association with metabolic disorders.

PubMed

Brum, Maria Carlota Borba; Filho, Fábio Fernandes Dantas; Schnorr, Claudia Carolina; Bottega, Gustavo Borchardt; Rodrigues, Ticiana C

2015-01-01

Although the health burden of shift work has not been extensively studied, evidence suggests that it may affect the metabolic balance and cause obesity and other metabolic disorders. Sleep deprivation, circadian desynchronization and behavioral changes in diet and physical activity are among the most commonly mentioned factors in studies of the association between night work and metabolic disorders. Individual adaptation to night work depends greatly on personal factors such as family and social life, but occupational interventions may also make a positive contribution to the transition to shift work, such as exposure to bright lights during the night shift, melatonin use, shift regularity and clockwise rotation, and dietary adaptations for the metabolic needs of night workers. The evaluation of the impact of night work on health and of the mechanisms underlying this relationship can serve as a basis for intervention strategies to minimize the health burden of shift work. This review aimed to identify highlights regarding therapeutic implications following the association between night and shift work and metabolic disorders, as well as the mechanisms and pathways responsible for these relationships.

Glucose metabolism during rotational shift-work in healthcare workers.

PubMed

Sharma, Anu; Laurenti, Marcello C; Dalla Man, Chiara; Varghese, Ron T; Cobelli, Claudio; Rizza, Robert A; Matveyenko, Aleksey; Vella, Adrian

2017-08-01

Shift-work is associated with circadian rhythm disruption and an increased risk of obesity and type 2 diabetes. We sought to determine the effect of rotational shift-work on glucose metabolism in humans. We studied 12 otherwise healthy nurses performing rotational shift-work using a randomised crossover study design. On each occasion, participants underwent an isotope-labelled mixed meal test during a simulated day shift and a simulated night shift, enabling simultaneous measurement of glucose flux and beta cell function using the oral minimal model. We sought to determine differences in fasting and postprandial glucose metabolism during the day shift vs the night shift. Postprandial glycaemic excursion was higher during the night shift (381±33 vs 580±48 mmol/l per 5 h, p<0.01). The time to peak insulin and C-peptide and nadir glucagon suppression in response to meal ingestion was also delayed during the night shift. While insulin action did not differ between study days, the beta cell responsivity to glucose (59±5 vs 44±4 × 10 -9  min -1 ; p<0.001) and disposition index were decreased during the night shift. Impaired beta cell function during the night shift may result from normal circadian variation, the effect of rotational shift-work or a combination of both. As a consequence, higher postprandial glucose concentrations are observed during the night shift.

Does age affect the relationship between control at work and sleep disturbance for shift workers?

PubMed

Loudoun, Rebecca Jane; Muurlink, Olav; Peetz, David; Murray, Georgina

2014-12-01

Among miners, shift work, aging and lack of control at work may be factors leading to increased sleep problems. Such risk factors may also operate in interaction, resulting in an even increased harm for sleep disruption. The present study aims at evaluating these relationships drawing on a sample of Australian mine and energy workers and their partners. The workers were mainly men. All performed shift work that included either nights (95%) or multiple shifts (92%), usually both (87%), while 36% were aged 50 years or above. The results show that low latitude over work activities is associated with higher sleep disturbances across the sample, though the effects are clearer amongst younger workers. By contrast, for younger workers, control over shift scheduling is not associated with sleep disturbances but for workers aged 50 or more, low control results in more sleep disturbance. Misalignment between shift workers and partner work schedules, and partner dissatisfaction with shift worker's employment and shift worker's work-life balance, are also associated with more sleep disturbances amongst shift workers.

The effect of sleep on item recognition and source memory recollection among shift-workers and permanent day-workers.

PubMed

Mawdsley, Matthew; Grasby, Katrina; Talk, Andrew

2014-10-01

We studied the effect of sleep versus wakefulness on item recognition and source memory recollection in a sample of shift-workers and permanent day-workers. Recognition of words that were previously viewed arrayed in quadrants of a page, and recollection of the original source location of the words on the page were assessed after a 12-h retention interval that was filled with wakefulness incorporating the subjects' work-shift, or an equal period that included sleep. Both shift-workers and permanent day-workers had poorer item recognition and source memory recollection when the retention interval was spent awake rather than including sleep. Shift-workers expressed larger deficits in performance than day-workers after wakefulness. This effect was not mediated by whether the shift-workers were on a day- or night-shift at the time of the study. These results indicate that sleep is an important contributor to successful item recognition and source recollection, and that mnemonic processing in shift-workers may be especially sensitive across their work-shift. © 2014 European Sleep Research Society.

Circadian Misalignment Increases C-Reactive Protein and Blood Pressure in Chronic Shift Workers.

PubMed

Morris, Christopher J; Purvis, Taylor E; Mistretta, Joseph; Hu, Kun; Scheer, Frank A J L

2017-04-01

Shift work is a risk factor for inflammation, hypertension, and cardiovascular disease. This increased risk cannot be fully explained by classical risk factors. Shift workers' behavioral and environmental cycles are typically misaligned relative to their endogenous circadian system. However, there is little information on the impact of acute circadian misalignment on cardiovascular disease risk in shift workers, independent of differences in work stress, food quality, and other factors that are likely to differ between night and day shifts. Thus, our objectives were to determine the independent effect of circadian misalignment on 24-h high-sensitivity C-reactive protein (hs-CRP; a marker of systemic inflammation) and blood pressure levels-cardiovascular disease risk factors-in chronic shift workers. Chronic shift workers undertook two 3-day laboratory protocols that simulated night work, comprising 12-hour inverted behavioral and environmental cycles (circadian misalignment) or simulated day work (circadian alignment), using a randomized, crossover design. Circadian misalignment increased 24-h hs-CRP by 11% ( p < 0.0001). Circadian misalignment increased 24-h systolic blood pressure (SBP) and diastolic blood pressure (DBP) by 1.4 mmHg and 0.8 mmHg, respectively (both p ≤ 0.038). The misalignment-mediated increase in 24-h SBP was primarily explained by an increase in SBP during the wake period (+1.7 mmHg; p = 0.017), whereas the misalignment-mediated increase in 24-h DBP was primarily explained by an increase in DBP during the sleep opportunity (+1.8 mmHg; p = 0.005). Circadian misalignment per se increases hs-CRP and blood pressure in shift workers. This may help explain the increased inflammation, hypertension, and cardiovascular disease risk in shift workers.

Did a brief nap break have positive benefits on information processing among nurses working on the first 8-h night shift?

PubMed

Chang, Yu-San; Wu, Yu-Hsuan; Lu, Mei Rou; Hsu, Chung-Yao; Liu, Ching-Kuan; Hsu, Chin

2015-05-01

Shift workers frequently experience acute sleep deprivation on first night shift. This study compared the efficacy of 30-min nap (between 2 and 3 a.m.) on the visual attention ability of the nurses working at first 8-h night shift at the time of maximum fatigue (between 3 and 4 a.m.). In addition, we measured cognitive function (between 9 and 10 a.m.) in nurses working on daytime shift, which we defined as baseline wakefulness. The results showed that working on the night shift groups was associated with sleep loss, leading to a decrease in visual attention performance compared to the daytime shift group. There was no statistically significant difference in the visual attention performance between those taking and not taking a nap during the night shift, however the effect size was medium in the information process. It was still needed increase sample size to draw the conclusion regarding a 30-min nap break have positive benefits on perceptual speed during the first night shift. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

The impact of meal timing on performance, sleepiness, gastric upset, and hunger during simulated night shift.

PubMed

Grant, Crystal Leigh; Dorrian, Jillian; Coates, Alison Maree; Pajcin, Maja; Kennaway, David John; Wittert, Gary Allen; Heilbronn, Leonie Kaye; Vedova, Chris Della; Gupta, Charlotte Cecilia; Banks, Siobhan

2017-10-07

This study examined the impact of eating during simulated night shift on performance and subjective complaints. Subjects were randomized to eating at night (n=5; 23.2 ± 5.5 y) or not eating at night (n=5; 26.2 ± 6.4 y). All participants were given one sleep opportunity of 8 h (22:00 h-06:00 h) before transitioning to the night shift protocol. During the four days of simulated night shift participants were awake from 16:00 h-10:00 h with a daytime sleep of 6 h (10:00 h-16:00 h). In the simulated night shift protocol, meals were provided at ≈0700 h, 1900 h and 0130 h (eating at night); or ≈0700 h, 0930 h, 1410 h and 1900 h (not eating at night). Subjects completed sleepiness, hunger and gastric complaint scales, a Digit Symbol Substitution Task and a 10-min Psychomotor Vigilance Task. Increased sleepiness and performance impairment was evident in both conditions at 0400 h (p<0.05). Performance impairment at 0400 h was exacerbated when eating at night. Not eating at night was associated with elevated hunger and a small but significant elevation in stomach upset across the night (p<0.026). Eating at night was associated with elevated bloating on night one, which decreased across the protocol. Restricting food intake may limit performance impairments at night. Dietary recommendations to improve night-shift performance must also consider worker comfort.

The impact of meal timing on performance, sleepiness, gastric upset, and hunger during simulated night shift

PubMed Central

GRANT, Crystal Leigh; DORRIAN, Jillian; COATES, Alison Maree; PAJCIN, Maja; KENNAWAY, David John; WITTERT, Gary Allen; HEILBRONN, Leonie Kaye; DELLA VEDOVA, Chris; GUPTA, Charlotte Cecilia; BANKS, Siobhan

2017-01-01

This study examined the impact of eating during simulated night shift on performance and subjective complaints. Subjects were randomized to eating at night (n=5; 23.2 ± 5.5 y) or not eating at night (n=5; 26.2 ± 6.4 y). All participants were given one sleep opportunity of 8 h (22:00 h-06:00 h) before transitioning to the night shift protocol. During the four days of simulated night shift participants were awake from 16:00 h-10:00 h with a daytime sleep of 6 h (10:00 h-16:00 h). In the simulated night shift protocol, meals were provided at ≈0700 h, 1900 h and 0130 h (eating at night); or ≈0700 h, 0930 h, 1410 h and 1900 h (not eating at night). Subjects completed sleepiness, hunger and gastric complaint scales, a Digit Symbol Substitution Task and a 10-min Psychomotor Vigilance Task. Increased sleepiness and performance impairment was evident in both conditions at 0400 h (p<0.05). Performance impairment at 0400 h was exacerbated when eating at night. Not eating at night was associated with elevated hunger and a small but significant elevation in stomach upset across the night (p<0.026). Eating at night was associated with elevated bloating on night one, which decreased across the protocol. Restricting food intake may limit performance impairments at night. Dietary recommendations to improve night-shift performance must also consider worker comfort. PMID:28740034

Effects of armodafinil on simulated driving and alertness in shift work disorder.

PubMed

Drake, Christopher; Gumenyuk, Valentina; Roth, Thomas; Howard, Ryan

2014-12-01

Forty-one percent of shift workers report dozing while driving. This study tested whether armodafinil improves driving simulator performance in subjects with shift work disorder (SWD). A primary outcome was performance late in the shift when workers are typically driving home. Randomized, double-blind, crossover. During each 12-h test session (21:30-09:30), subjects were kept awake except for multiple sleep latency testing (MSLT: 01:30, 03:30, 05:30, and 07:30). Subjective sleepiness (Karolinska Sleepiness Scale, KSS), driving performance, and cognitive performance (digit symbol substitution test and creativity on the Remote Associates Test, RAT) were evaluated during the night shift and commute home times. Hospital-based sleep research laboratory. Twenty night workers (age: 42.7 ± 8.7 y, 17 F) with excessive sleepiness (≥ 10 on the Epworth Sleepiness Scale), meeting International Classification of Sleep Disorders, Second Edition (ICSD-2) criteria for SWD, and having no other medical conditions. Armodafinil (150 mg) or placebo at (23:45 h) on counterbalanced nights separated by 7-14 days. Primary endpoints were driving simulator performance (standard deviation of lateral position (SDLP) and off-road deviations) with four sessions starting 3.25 h after drug administration, objective sleepiness (MSLT; 1.75 to 7.75 h post-drug), and creativity (5 h post-drug). Significant effects of drug were observed for each driving measure (P < 0.05). Armodafinil significantly improved SDLP for simulator sessions at 05:30, 07:30, and 09:30, and off-road deviations at 7 h, 15 min and 9 h, 15 min post-drug (P < 0.05). Armodafinil also improved objective sleepiness from 3.7 ± 0.6 min to 9.7 ± 5.2 min (P < 0.001) and RAT score from 8.75 ± 4.9 to 11.25 ± 6.0 (P < 0.005). Armodafinil 150 mg early in the night shift improves driving simulator performance in SWD. Effects on sleepiness, cognition, and driving were found up to 9.5 h post-ingestion, during the critical time when many night workers are driving home. © 2014 Associated Professional Sleep Societies, LLC.

Shift work--problems and its impact on female nurses in Udaipur, Rajasthan India.

PubMed

Rathore, H; Shukla, K; Singh, S; Tiwari, G

2012-01-01

Abstract : There is good evidence that shift work has negative effects on workers health, safety and performance. It is quite appropriate that attention is paid to this very important feature of socio-technical systems, which may adversely affect mental and physical health, social life and safety of shift workers. Research into the impact of shift work on professionals has consistently identified a range of negative outcomes in physical, psychological, and social domains (Akerstedt, 1988; Costa, Lievore, Casaletti, Gaffuri, & Folkard, 1989; Kogi, 2005; Paley & Tepas, 1994). Hospitals, the biggest employer in the health care field, employ more night shift workers than any other industry. It can therefore be inferred that in medical domain high percentage of workforce may be affected by problems related to shift work. Thus the present study will provide knowledge base for the problems faced by the female nurses. The present study was undertaken with an objective of getting an insight into the problems faced by female nurses in shift work. . It was found that the female nurses in India worked on roaster pattern of change in shift every seven days. They did not have a say in the change of duties, it could only be done on mutual grounds. Partners of younger group did not much adjust to their shift pattern this created stress among the nurses.The results showed that the female nurses in both the age groups i.e. 30-45 years and 45-60 years faced many problems related to health and well being, fatigue, social and domestic situations. They could not give much time to their children in particular. Travelling in nights was risky for them. Common problem was the insufficient sleep during night shifts. The nurses had to cater to the needs of the family, children in particular along with the adjustments to be made due to shift work. They had to sometimes do the night duties and attend social functions as a part of their duty. Children and husband in some cases did not cooperate this lead to frustration. When asked as to whether they would could shift job if they get regular one more than 50 % said yes this means that there need to be come training and intervention for the shift workers and their family so that the problems faced and their impact on personal health of the female nurses could be reduced.

Administrative rationality and coping strategies in shift work.

PubMed

Lieber, Renato Rocha; Kvieska, Rodrigo Neiva; Delamaro, Maurício Cesar

2012-01-01

Shift work (SW) can affect worker health and productivity. Working at night, workers often accumulate fatigue and are less productive. In Brazil, laws have been drafted aiming to reduce night work and rotating shift hours. In order to slash costs, companies have been looking for new arrangements to improve productivity under these conditions. The purpose of this study was to examine management changes and their outcomes in a large glass factory located in an industrial region of Brazil. The results show that the management, seeking equal productivity among shifts, focused its efforts mainly on distributing employee expertise. The arrangement resulted in 12 different groups that combine to serve three fixed shifts. A same shift can be served by more than one group, and the members of a same group share days off on different days. There was no statistically significant productivity difference among the three shifts. The on-site examination showed that part of the production was held by the workers and transferred to the next shift in order for them to be able to meet the management's performance rate requirements. The finding shows how a Brazilian cultural trait (resistance without conflict) is used to drive coping in SW.

Adaptation to Shift Work: Physiologically Based Modeling of the Effects of Lighting and Shifts’ Start Time

PubMed Central

Postnova, Svetlana; Robinson, Peter A.; Postnov, Dmitry D.

2013-01-01

Shift work has become an integral part of our life with almost 20% of the population being involved in different shift schedules in developed countries. However, the atypical work times, especially the night shifts, are associated with reduced quality and quantity of sleep that leads to increase of sleepiness often culminating in accidents. It has been demonstrated that shift workers’ sleepiness can be improved by a proper scheduling of light exposure and optimizing shifts timing. Here, an integrated physiologically-based model of sleep-wake cycles is used to predict adaptation to shift work in different light conditions and for different shift start times for a schedule of four consecutive days of work. The integrated model combines a model of the ascending arousal system in the brain that controls the sleep-wake switch and a human circadian pacemaker model. To validate the application of the integrated model and demonstrate its utility, its dynamics are adjusted to achieve a fit to published experimental results showing adaptation of night shift workers (n = 8) in conditions of either bright or regular lighting. Further, the model is used to predict the shift workers’ adaptation to the same shift schedule, but for conditions not considered in the experiment. The model demonstrates that the intensity of shift light can be reduced fourfold from that used in the experiment and still produce good adaptation to night work. The model predicts that sleepiness of the workers during night shifts on a protocol with either bright or regular lighting can be significantly improved by starting the shift earlier in the night, e.g.; at 21∶00 instead of 00∶00. Finally, the study predicts that people of the same chronotype, i.e. with identical sleep times in normal conditions, can have drastically different responses to shift work depending on their intrinsic circadian and homeostatic parameters. PMID:23308206

Can you see me? Experiences of nurses working night shift in Australian regional hospitals: a qualitative case study.

PubMed

Powell, Idona

2013-10-01

To report a study that explored the experiences of night-shift nurses, focusing on employee interrelationships and work satisfaction. Night-shift nurses are a critical component in hospital care making it essential to understand the experiences that give meaning to their work and understand how these nurses and the organization can benefit from their contribution to hospital care. A literature review revealed minimal research in this area. Qualitative case study. A qualitative case study using semi-structured interviews and self-completed diaries was conducted in 2010 in regional public hospitals in Australia. Participants were 14 nurses working nights half or more of their shifts in medical or surgical wards. Thematic analysis identified four major areas of concern: work relationships, work environment, work practices and lifestyle impact. Notably, work relationships were most meaningful for nurses on the same shift; night-shift nurses experienced working conditions inferior to their daytime counterparts including a perception of minimal leadership. Despite limited education opportunities, night shift provided opportunity for professional growth for some nurses with a slippage in skills for others; night shift provided flexibility for family and social activities, yet impeded these same activities, primarily due to pervasive fatigue. Night-shift nurses considered their role critical, yet believed that they were poorly regarded. The strong interpersonal relationships developed between night-shift workers need to be capitalized on whilst developing a more effective leadership model, improved work environment, more equitable professional development, and genuine recognition of the critical role of night nurses. © 2013 Blackwell Publishing Ltd.

The Impact of Meal Timing on Cardiometabolic Syndrome Indicators in Shift Workers

PubMed Central

Molzof, Hylton E.; Wirth, Michael D.; Burch, James B.; Shivappa, Nitin; Hébert, James R.; Johnson, Russell L.; Gamble, Karen L.

2017-01-01

The aims of this study were to 1) compare the inflammatory potential of night- and day-shift nurses’ diets in regard to time-of-day and work status, and 2) explore how the timing of food intake during work and off-work is associated with cardiometabolic syndrome (CMS) risk factors between these two groups. Female nurses (N = 17; 8 day-shift and 9 night-shift) reported food intake over 9 days. On a middle day off of work, metabolic parameters were measured after an overnight fast. Energy/macronutrient intake and inflammatory potential of dietary intake (as assessed via the Dietary Inflammatory IndexTM) were calculated for nurses’ workdays, work nights, off-work days, and off-work nights. Work-night total food intake (grams) accounted for a significant amount of variance in CMS risk factors for night-shift nurses only. Increased total gram consumption during night-shift nurses’ work nights was associated with increased lipid levels – independent of the macronutrient composition of the food consumed. Alternatively, for night-shift nurses, work-day intake of several food parameters accounted for a significant proportion of variance in HDL cholesterol levels, with higher intake associated with higher HDL levels. For both day- and night-shift nurses, food intake during the day was more pro-inflammatory regardless of shift-type or work status. Our novel approach of combining time-of-day-specific and work-day-specific analyses of dietary inflammatory factors and macronutrient composition with measurement of CMS risk factors suggests a link between meal timing and cardiometabolic health for shift-working nurses. PMID:28107043

Effects of Shift Work on the Postural and Psychomotor Performance of Night Workers

PubMed Central

Narciso, Fernanda Veruska; Barela, José A.; Aguiar, Stefane A.; Carvalho, Adriana N. S.; Tufik, Sergio; de Mello, Marco Túlio

2016-01-01

The purpose of the study was to investigate the effects of shift work on the psychomotor and postural performance of night workers. The study included 20 polysomnography technicians working schedule of 12-h night shift by 36-h off. On the first day of protocol, the body mass and height were measured, and an actigraph was placed on the wrist of each participant. On the second day of protocol, sleepiness by Karolinska Sleepiness Scale, postural control by force platform (30 seconds) and psychomotor performance by Psychomotor Vigilance Task (10 minutes) were measured before and after 12-h night work. Results showed that after 12-h night work, sleepiness increased by 59% (p<0.001), postural control variables increased by 9% (p = 0.048), and 14% (p = 0.006). Mean reaction time, and the number of lapses of attention increased by 13% (p = 0.006) and 425% (p = 0.015), respectively, but the mean reciprocal reaction time decreased by 7%. In addition, there were correlations between sleepiness and postural control variables with opened eyes (r = 0.616, 95% confidence interval [CI] = 0.361–0.815; r = 0.538; 95% CI = 0.280–0.748) and closed eyes (r = 0.557; 95% CI = 0.304–0.764, r = 0497; 95% CI = 0.325–0.715) and a pronounced effect of sleepiness on postural sway (R2 = 0.393; 95% CI = 0.001–0.03). Therefore, 12-h night work system and sleepiness showed a negative impact in postural and psychomotor vigilance performance of night workers. As unexpected, the force platform was feasibility to detect sleepiness in this population, underscoring the possibility of using this method in the workplace to prevent occupational injuries and accidents. PMID:27115868

Effects of Shift Work on the Postural and Psychomotor Performance of Night Workers.

PubMed

Narciso, Fernanda Veruska; Barela, José A; Aguiar, Stefane A; Carvalho, Adriana N S; Tufik, Sergio; de Mello, Marco Túlio

2016-01-01

The purpose of the study was to investigate the effects of shift work on the psychomotor and postural performance of night workers. The study included 20 polysomnography technicians working schedule of 12-h night shift by 36-h off. On the first day of protocol, the body mass and height were measured, and an actigraph was placed on the wrist of each participant. On the second day of protocol, sleepiness by Karolinska Sleepiness Scale, postural control by force platform (30 seconds) and psychomotor performance by Psychomotor Vigilance Task (10 minutes) were measured before and after 12-h night work. Results showed that after 12-h night work, sleepiness increased by 59% (p<0.001), postural control variables increased by 9% (p = 0.048), and 14% (p = 0.006). Mean reaction time, and the number of lapses of attention increased by 13% (p = 0.006) and 425% (p = 0.015), respectively, but the mean reciprocal reaction time decreased by 7%. In addition, there were correlations between sleepiness and postural control variables with opened eyes (r = 0.616, 95% confidence interval [CI] = 0.361-0.815; r = 0.538; 95% CI = 0.280-0.748) and closed eyes (r = 0.557; 95% CI = 0.304-0.764, r = 0497; 95% CI = 0.325-0.715) and a pronounced effect of sleepiness on postural sway (R2 = 0.393; 95% CI = 0.001-0.03). Therefore, 12-h night work system and sleepiness showed a negative impact in postural and psychomotor vigilance performance of night workers. As unexpected, the force platform was feasibility to detect sleepiness in this population, underscoring the possibility of using this method in the workplace to prevent occupational injuries and accidents.

Night work, light exposure and melatonin on work days and days off.

PubMed

Daugaard, Stine; Garde, Anne Helene; Bonde, Jens Peter Ellekilde; Christoffersen, Jens; Hansen, Äse Marie; Markvart, Jakob; Schlünssen, Vivi; Skene, Debra J; Vistisen, Helene Tilma; Kolstad, Henrik A

2017-01-01

We aimed to examine the effects of night work on salivary melatonin concentration during and subsequent to night work and the mediating role of light. We included 254 day workers and 87 night workers who were followed during 322 work days and 301 days off work. Each day was defined as the 24 hour period starting from the beginning of a night shift or from waking in the mornings with day work and days off. Light levels were recorded and synchronized with diary information (start and end of sleep and work). On average, participants provided four saliva samples per day, and these were analyzed for melatonin concentration by liquid chromatography tandem mass spectrometry (LC-MS/MS). Differences between day and night workers on work days and days off were assessed with multilevel regression models with melatonin concentration as the primary outcome. All models were stratified or adjusted by time of day. For light exposure, we estimated the total, direct and indirect effects of night work on melatonin concentrations obtaining 95% confidence intervals through bootstrapping. On work days, night workers showed 15% lower salivary melatonin concentrations compared with day workers (-15.0%; 95% CI: -31.4%; 5.2%). During the night, light exposure mediated a melatonin suppression of approximately 6% (-5.9%, 95% CI: -10.2%; -1.5%). No mediating effect of light was seen during the day time. On days off, we observed no difference in melatonin concentrations between day and night workers. These findings are in accordance with a transient and partly light-mediated effect of night work on melatonin production.

Working the night shift: a necessary time for training or a risk to health and safety?

PubMed

Morrison, I; Flower, D; Hurley, J; McFadyen, R J

2013-01-01

The European Working Time Directive (EWTD) limits excessive night shifts and restricts the working week to no more than 48 hours. The underlying rationale is to minimise the health risks to all workers. Here we debate the impact of night rotas for doctors-in-training on patient safety and medical education; when the EWTD was agreed these topics may not have been considered, either systematically or objectively. The impacts of diurnal rhythms on human functions affect all night workers, but the nature of rostered medical and surgical work has little precedent in other industries or even in the contracts of other healthcare staff. For example, rostered night duties need to be distinguished from permanent night shift work. On-call medical night work from training doctors is generally required for short periods and usually involves fewer patients. It is an important time in training, where clinical responsibility and decision-making can be matured in a supervised setting. To comply with the EWTD most hospitals have adopted rota patterns that aim to cover the clinical needs, while ensuring no doctor works for more than 48 hours in an average working week. To monitor this process longterm studies are necessary to evaluate effects on a doctor's health and on patient care generally. The EWTD has also led to a loss of continuity of patient care; does this really matter?

[NIGHT SHIFT WORK AND HEALTH DISORDER RISK IN FEMALE WORKERS].

PubMed

Kukhtina, E G; Solionova, L G; Fedichkina, T P; Zykova, I E

2015-01-01

There was evaluated the risk to health in females employed in shift work, including night shifts. According to the data of periodical medical examinations health indices of 403 females employed in shift work, including night shifts, were compared with indices of 205 females--workers of administrative units of the same enterprise. Overall relative risk (RR) for the health disorder associated with the night shift was 1.2 (95%; confidence interval (CI): 1.09-1.28). A statistically significant increase in risk was observed in relation to uterine fibroids (OR 1.3; 95% CI: 1.06-1.54), mastopathy (OR 1.4; 95% CI: 1.2-1.6), inorganic sleep disorders (OR 8.8; 95% CI 2.6-29.8). At the boundary of the statistical significance there was the increase in the risk for obesity (OR 1.2; 95% C: 0.97-1.39), hypertension (OR 1.2; 95% CI, 0.9-1.5) and endometriosis (OR 1.5; 95% CI: 0.98-2.16). There was revealed an adverse effect of night shifts on the gestation course: ectopic pregnancy in the experimental group occurred 6.6 times more frequently than in the control group (95% CI: 0.87-50.2), and spontaneous abortion--1.7 times (95% CI: 0.95-3.22). The performed study has once again confirmed the negative impact of smoking on women's reproductive health: smoking women in the experimental group compared with the control group smokers had 2.7 times increased risk of uterine fibroids (within 1.06-7.0), the risk in non-smokers was significantly lower--1.2 (0.98-1.4). The findings suggest about a wide range of health problems related to employment on shift work, including night shifts, which indicates to the need for adoption of regulatory and preventive measures aimed to this professional group.

Measuring Light at Night and Melatonin Levels in Shift Workers: A Review of the Literature.

PubMed

Hunter, Claudia M; Figueiro, Mariana G

2017-07-01

Shift work, especially that involving rotating and night shifts, is associated with an increased risk of diseases, including cancer. Attempts to explain the association between shift work and cancer in particular have focused on the processes of melatonin production and suppression. One hypothesis postulates that exposure to light at night (LAN) suppresses melatonin, whose production is known to slow the development of cancerous cells, while another proposes that circadian disruption associated with shift work, and not just LAN, increases health risks. This review focuses on six studies that employed quantitative measurement of LAN and melatonin levels to assess cancer risks in shift workers. These studies were identified via searching the PubMed database for peer-reviewed, English-language articles examining the links between shift work, LAN, and disease using the terms light at night, circadian disruption, health, risk, cancer, shift work, or rotating shift. While the results indicate a growing consensus on the relationship between disease risks (particularly cancer) and circadian disruption associated with shift work, the establishment of a direct link between LAN and disease has been impeded by contradictory studies and a lack of consistent, quantitative methods for measuring LAN in the research to date. Better protocols for assessing personal LAN exposure are required, particularly those employing calibrated devices that measure and sample exposure to workplace light conditions, to accurately assess LAN's effects on the circadian system and disease. Other methodologies, such as measuring circadian disruption and melatonin levels in the field, may also help to resolve discrepancies in the findings.

Circadian type, chronic fatigue, and serum IgM in the shift workers of an industrial organization

PubMed Central

Khaleghipour, Shahnaz; Masjedi, Mohsen; Kelishadi, Roya

2015-01-01

Background: Night shift workers are more vulnerable to immune-related diseases. Immunoglobulin M (IgM) is a potent activator of complement, and complement has a crucial role in defense against bacterial infections. Circadian type is known as an effective agent on vulnerability and adaptation with shift work due to non-compliance with shift stress. The objective of this study was to investigate the correlation of circadian type and chronic fatigue with the serum concentration of IgM in a group of shift workers. Materials and Methods: This cross-sectional study was performed in an industrial organization in Isfahan, Iran. The study population consisted of 221 male employees working at night shifts who were selected by random cluster sampling. The following questionnaires were used: composite morningness (Torsvall and Akerstedt), circadian type (Folkard), and chronic fatigue (Barton and colleagues). The serum concentration of IgM was measured by the nephelometric method. The data were analyzed with the Pearson coefficient correlation and the path analysis for finding the pattern of the structural equations to evaluate the direct and indirect relationships between variables, using the SPSS 15 and LISREL 8.5 statistical software. Results: Significant correlation was documented between morningness, flexibility, languidness, and chronic fatigue with the serum concentration of IgM (P < 0.01). Conclusion: The results showed that the shift workers with morningness and languidness experienced more problems during the working hours due to more tiredness, and had decreased serum concentration of IgM. Correct management of shift work may attenuate fatigue in workers and also improve many health issues experienced by the shift workers. PMID:25802830

Meta-analysis on night shift work and risk of metabolic syndrome.

PubMed

Wang, F; Zhang, L; Zhang, Y; Zhang, B; He, Y; Xie, S; Li, M; Miao, X; Chan, E Y Y; Tang, J L; Wong, M C S; Li, Z; Yu, I T S; Tse, L A

2014-09-01

This study aims to quantitatively summarize the association between night shift work and the risk of metabolic syndrome (MetS), with special reference to the dose-response relationship with years of night shift work. We systematically searched all observational studies published in English on PubMed and Embase from 1971 to 2013. We extracted effect measures (relative risk, RR; or odd ratio, OR) with 95% confidence interval (CI) from individual studies to generate pooled results using meta-analysis approach. Pooled RR was calculated using random- or fixed-effect model. Downs and Black scale was applied to assess the methodological quality of included studies. A total of 13 studies were included. The pooled RR for the association between 'ever exposed to night shift work' and MetS risk was 1.57 (95% CI = 1.24-1.98, pheterogeneity  = 0.001), while a higher risk was indicated in workers with longer exposure to night shifts (RR = 1.77, 95% CI = 1.32-2.36, pheterogeneity  = 0.936). Further stratification analysis demonstrated a higher pooled effect of 1.84 (95% CI = 1.45-2.34) for studies using the NCEP-ATPIII criteria, among female workers (RR = 1.61, 95% CI = 1.10-2.34) and the countries other than Asia (RR = 1.65, 95% CI = 1.39-1.95). Sensitivity analysis confirmed the robustness of the results. No evidence of publication bias was detected. The present meta-analysis suggested that night shift work is significantly associated with the risk of MetS, and a positive dose-response relationship with duration of exposure was indicated. © 2014 The Authors. obesity reviews © 2014 World Obesity.

The association of body size in early to mid-life with adult urinary 6-sulfatoxymelatonin levels among night shift health care workers.

PubMed

Ramin, Cody A; Massa, Jennifer; Wegrzyn, Lani R; Brown, Susan B; Pierre-Paul, Jeffrey; Devore, Elizabeth E; Hankinson, Susan E; Schernhammer, Eva S

2015-05-06

Adult body mass index (BMI) has been associated with urinary melatonin levels in humans; however, whether earlier-life body size is associated with melatonin, particularly among night shift workers, remains unknown. We evaluated associations of birth weight, body shape (or somatotype) at ages 5 and 10, BMI at age 18 and adulthood, weight change since age 18, waist circumference, waist to hip ratio, and height with creatinine-adjusted morning urinary melatonin (6-sulfatoxymelatonin, aMT6s) levels among 1,343 healthy women (aged 32-53 at urine collection, 1996-1999) in the Nurses' Health Study (NHS) II cohort. Using multivariable linear regression, we computed least-square mean aMT6s levels across categories of body size, and evaluated whether these associations were modified by night shift work. Adult BMI was inversely associated with aMT6s levels (mean aMT6s levels = 34 vs. 50 ng/mg creatinine, comparing adult BMI ≥ 30 vs. <20 kg/m(2); P trend < 0.0001); however, other measures of body size were not related to aMT6s levels after accounting for adult BMI. Night shifts worked prior to urine collection, whether recent or cumulatively over time, did not modify the association between adult BMI and aMT6s levels (e.g., P interaction = 0.72 for night shifts worked within two weeks of urine collection). Our results suggest that adult BMI, but not earlier measures of body size, is associated with urinary aMT6s levels in adulthood. These observations did not vary by night shift work status, and suggest that adult BMI may be an important mechanism by which melatonin levels are altered and subsequently influence chronic disease risk.

Shift schedules, work factors, and mental health among onshore and offshore workers in the Norwegian petroleum industry

PubMed Central

BERTHELSEN, Mona; PALLESEN, Ståle; BJORVATN, Bjørn; KNARDAHL, Stein

2015-01-01

The purpose of the present study was to answer the following research questions: (1) Do workers in different shift schedules differ in mental distress? (2) Do workers in different shift schedules differ in neuroticism? (3) Do shift schedules differ in psychosocial work exposures? (4) Do psychosocial work exposures contribute to mental distress among onshore- and offshore workers? (5) Does neuroticism confound the association between work exposures and mental distress? Workers on six shift-schedules answered a questionnaire (1,471 of 2,628 employees). Psychological and social work factors were measured by QPSNordic, mental distress was measured by HADS and neuroticism was measured by EPQ. The results showed 1) No differences in mental distress between workers in different shift schedules, 2) Revolving-shift workers reported higher neuroticism compared to day workers, 3) Swing-shift workers and revolving-shift workers reported lower job control compared to permanent-night and -day workers, 4) Job demands and role conflict were associated with more mental distress. Job control, role clarity, support, and leadership were associated with lower mental distress, 5) Neuroticism influenced the relationship between psychosocial work factors and mental distress. The present study did not find differences in mental distress between shift schedules. Job characteristics may be contributing factors when determining health effects of shift work. PMID:25740007

Shift schedules, work factors, and mental health among onshore and offshore workers in the Norwegian petroleum industry.

PubMed

Berthelsen, Mona; Pallesen, Ståle; Bjorvatn, Bjørn; Knardahl, Stein

2015-01-01

The purpose of the present study was to answer the following research questions: (1) Do workers in different shift schedules differ in mental distress? (2) Do workers in different shift schedules differ in neuroticism? (3) Do shift schedules differ in psychosocial work exposures? (4) Do psychosocial work exposures contribute to mental distress among onshore- and offshore workers? (5) Does neuroticism confound the association between work exposures and mental distress? Workers on six shift-schedules answered a questionnaire (1,471 of 2,628 employees). Psychological and social work factors were measured by QPSNordic, mental distress was measured by HADS and neuroticism was measured by EPQ. The results showed 1) No differences in mental distress between workers in different shift schedules, 2) Revolving-shift workers reported higher neuroticism compared to day workers, 3) Swing-shift workers and revolving-shift workers reported lower job control compared to permanent-night and -day workers, 4) Job demands and role conflict were associated with more mental distress. Job control, role clarity, support, and leadership were associated with lower mental distress, 5) Neuroticism influenced the relationship between psychosocial work factors and mental distress. The present study did not find differences in mental distress between shift schedules. Job characteristics may be contributing factors when determining health effects of shift work.

[Mental health status in railway female workers and its occupational influencing factors].

PubMed

Ji, F L; Liu, Z M; Liu, Z S; Zou, J F; Yu, W L; Li, H M; Li, J; Kong, L M; Jiang, Q

2018-02-20

Objective: To investigate the mental health status of railway female workers and related influencing factors, and to provide a scientific strategy for labor protection regulations in railway female workers. Methods: Cluster sampling was used to select 5033 female workers from Jinan, Nanning, Qinghai-Tibet, and Wuhan railway systems in China from January to August, 2016. A uniform reproductive health questionnaire, as well as the Symptom Checklist-90 (SCL-90) , was used to investigate their general information (age, marital status, education level, and family income) , work type (day shift, night shift, or work on shift) , work position, and the presence or absence of exposure to occupational hazardous factors. The score on each factor of SCL-90 and the positive rate of mental health status were calculated. Results: The positive rate of mental health status was 10.6% in railway female workers. The workers exposed to occupational hazardous factors had a significantly higher positive rate of mental health status than those not exposed to occupational hazardous factors (14.20% vs 8.02%, P <0.01) . There were significant differences in the positive rate of mental health status between workers with different ages, marital status, education levels, histories of abortion, or annual family income levels ( P <0.01) . The scores of somatization (1.54±0.62) and horror (1.28±0.47) in SCL-90 were significantly higher than the Chinese adult norm ( P <0.01) . The multivariate logistic regression analysis showed that exposure to occupational hazardous factors, night shift, overwork, and carrying heavy objects were associated with mental health problems ( OR =1.797, 95% CI : 1.393-2.318; OR =0.641, 95% CI : 0.498-0.827; OR =0.586, 95% CI : 0.439-0.783; OR =0.580, 95% CI : 0.378-0.890) . Conclusion: Railway female workers have lower levels of mental health than the general population and are under significant occupational stress. Exposure to occupational hazardous factors, night shift, overwork, and carrying heavy objects are associated with the development of mental health problems in railway female workers.

Job characteristics and musculoskeletal pain among shift workers of a poultry processing plant in Southern Brazil.

PubMed

Barro, Dânia; Olinto, Maria Teresa Anselmo; Macagnan, Jamile Block Araldi; Henn, Ruth Liane; Pattussi, Marcos Pascoal; Faoro, Mariana Wentz; Garcez, Anderson da Silva; Paniz, Vera Maria Vieira

2015-01-01

The purpose of this study was to evaluate the association between job characteristics and musculoskeletal pain among shift workers employed at a 24-hour poultry processing plant in Southern Brazil. This was a cross-sectional study of 1,103 production line workers aged 18-52 years. The job characteristics of interest were shift (day/night), shift duration, and plant sector ambient temperature. Musculoskeletal pain was defined as self-reported occupational-related pain in the upper or lower extremities and trunk, occurring often or always, during the last 12 months. The mean (SD) participant age was 30.8 (8.5) years, and 65.7% of participants were women. The prevalence of musculoskeletal pain was greater among female participants than male participants. After adjustment for job characteristics and potential confounders, the prevalence ratios (PR) of lower extremity musculoskeletal pain among female workers employed in extreme-temperature conditions those working the night shift, and those who had been working longer on the same shift were 1.75 (95% CI 1.12, 2.71), 1.69 (95% CI 1.05, 2.70), and 1.64 (95% CI 1.03, 2.62), respectively. In male workers, only extreme-temperature conditions showed a significant association with lower extremity musculoskeletal pain (PR=2.17; 95% CI 1.12, 4.22) after adjustment analysis. These findings suggest a need for implementation of measures to mitigate the damage caused by nighttime work and by working under extreme temperature conditions, especially among female shift workers, such as changing positions frequently during work and implementation of rest breaks and a workplace exercise program, so as to improve worker quality of life.

Night shift work and stomach cancer risk in the MCC-Spain study.

PubMed

Gyarmati, Georgina; Turner, Michelle C; Castaño-Vinyals, Gemma; Espinosa, Ana; Papantoniou, Kyriaki; Alguacil, Juan; Costas, Laura; Pérez-Gómez, Beatriz; Martin Sanchez, Vicente; Ardanaz, Eva; Moreno, Victor; Gómez-Acebo, Inés; Fernández-Tardon, Guillermo; Villanueva Ballester, Vicent; Capelo, Rocio; Chirlaque, Maria-Dolores; Santibáñez, Miguel; Pollán, Marina; Aragonés, Nuria; Kogevinas, Manolis

2016-08-01

Night shift work has been classified as a probable human carcinogen by the International Agency for Research on Cancer, based on experimental studies and limited evidence on human breast cancer risk. Evidence at other cancer sites is scarce. We evaluated the association between night shift work and stomach cancer risk in a population-based case-control study. A total of 374 incident stomach adenocarcinoma cases and 2481 population controls were included from the MCC-Spain study. Detailed data on lifetime night shift work were collected including permanent and rotating shifts, and their cumulative duration (years). Adjusted unconditional logistic regression models were used in analysis. A total of 25.7% of cases and 22.5% of controls reported ever being a night shift worker. There was a weak positive, non-significant association between ever having had worked for at least 1 year in permanent night shifts and stomach cancer risk compared to never having worked night shifts (OR=1.2, 95% CI 0.9 to 1.8). However, there was an inverse 'U' shaped relationship with cumulative duration of permanent night shifts, with the highest risk observed in the intermediate duration category (OR 10-20 years=2.0, 95% CI 1.1 to 3.6) (p for trend=0.19). There was no association with ever having had worked in rotating night shifts (OR=0.9, 95% CI 0.6 to 1.2) and no trend according to cumulative duration (p for trend=0.68). We found no clear evidence concerning an association between night shift work and stomach cancer risk. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Sleep interruption associated with house staff work schedules alters circadian gene expression.

PubMed

Fang, Ming Zhu; Ohman-Strickland, Pamela; Kelly-McNeil, Kathie; Kipen, Howard; Crabtree, Benjamin F; Lew, Jenny Pan; Zarbl, Helmut

2015-11-01

Epidemiological studies indicate that disruption of circadian rhythm by shift work increases the risk of breast and prostate cancer. Our studies demonstrated that carcinogens disrupt the circadian expression of circadian genes (CGs) and circadian-controlled genes (CCGs) during the early stages of rat mammary carcinogenesis. A chemopreventive regimen of methylselenocysteine (MSC) restored the circadian expression of CGs and CCGs, including PERIOD 2 (PER2) and estrogen receptor β (ERS2), to normal. The present study evaluated whether changes in CG and CCG expression in whole blood can serve as indicators of circadian disruption in shift workers. Fifteen shift workers were recruited to a crossover study. Blood samples were drawn before (6 PM) and after (8 AM) completing a night shift after at least seven days on floating night-shift rotation, and before (8 AM), during (1 PM), and after (6 PM) completing seven days on day shift. The plasma melatonin level and messenger RNA (mRNA) expression of PER2, nuclear receptor subfamily 1, group d, member 1 (NR1D1), and ERS2 were measured, and the changes in levels of melatonin and gene expression were evaluated with statistical analyses. The mRNA expression of PER2 was affected by shift (p = 0.0079); the levels were higher in the evening for the night shift, but higher in the morning for the day shift. Increased PER2 expression (p = 0.034) was observed in the evening on the night versus day shifts. The melatonin level was higher in the morning for both day shifts (p = 0.013) and night shifts (p <0.0001). Changes in the level of PER2 gene expression can serve as a biomarker of disrupted circadian rhythm in blood cells. Therefore, they can be a useful intermediate indicator of efficacy in future MSC-mediated chemoprevention studies. Copyright © 2015 Elsevier B.V. All rights reserved.

Pharmacological interventions for sleepiness and sleep disturbances caused by shift work.

PubMed

Liira, Juha; Verbeek, Jos H; Costa, Giovanni; Driscoll, Tim R; Sallinen, Mikael; Isotalo, Leena K; Ruotsalainen, Jani H

2014-08-12

Shift work results in sleep-wake disturbances, which cause sleepiness during night shifts and reduce sleep length and quality in daytime sleep after the night shift. In its serious form it is also called shift work sleep disorder. Various pharmacological products are used to ameliorate symptoms of sleepiness or poor sleep length and quality. To evaluate the effects of pharmacological interventions to reduce sleepiness or to improve alertness at work and decrease sleep disturbances whilst off work, or both, in workers undertaking shift work in their present job and to assess their cost-effectiveness. We searched CENTRAL, MEDLINE, EMBASE, PubMed and PsycINFO up to 20 September 2013 and ClinicalTrials.gov up to July 2013. We also screened reference lists of included trials and relevant reviews. We included all eligible randomised controlled trials (RCTs), including cross-over RCTs, of pharmacological products among workers who were engaged in shift work (including night shifts) in their present jobs and who may or may not have had sleep problems. Primary outcomes were sleep length and sleep quality while off work, alertness and sleepiness, or fatigue at work. Two authors independently selected studies, extracted data and assessed risk of bias in included trials. We performed meta-analyses where appropriate. We included 15 randomised placebo-controlled trials with 718 participants. Nine trials evaluated the effect of melatonin and two the effect of hypnotics for improving sleep problems. One trial assessed the effect of modafinil, two of armodafinil and one examined caffeine plus naps to decrease sleepiness or to increase alertness.Melatonin (1 to 10 mg) after the night shift may increase sleep length during daytime sleep (mean difference (MD) 24 minutes, 95% confidence interval (CI) 9.8 to 38.9; seven trials, 263 participants, low quality evidence) and night-time sleep (MD 17 minutes, 95% CI 3.71 to 30.22; three trials, 234 participants, low quality evidence) compared to placebo. We did not find a dose-response effect. Melatonin may lead to similar sleep latency times as placebo (MD 0.37minutes, 95% CI - 1.55 to 2.29; five trials, 74 participants, low quality evidence).Hypnotic medication, zopiclone, did not result in significantly longer daytime sleep length compared to placebo in one low quality trial and we could not use the data from the study on lormetazepam.Armodafinil taken before the night shift probably reduces sleepiness by one point on the Karolinska Sleepiness Scale (KSS) (MD -0.99, 95% CI -1.32 to -0.67; range 1 to 10; two trials, 572 participants, moderate quality evidence) and increases alertness by 50 ms in a simple reaction time test (MD -50.0, 95% CI -85.5 to -15.5) at three months' follow-up in shift work sleep disorder patients. Modafinil probably has similar effects on sleepiness (KSS) (MD -0.90, 95% CI -1.45 to -0.35; one trial, 183 participants, moderate quality evidence) and alertness in the psychomotor vigilance test in the same patient group. Post-marketing, severe skin reactions have been reported. Adverse effects reported by trial participants were headache, nausea and a rise in blood pressure. There were no trials in non-patient shift workers.Based on one trial, caffeine plus pre-shift naps taken before the night shift decreased sleepiness (KSS) (MD -0.63, 95% CI -1.09 to -0.17).We judged most trials to have a low risk of bias even though the randomisation method and allocation concealment were often not described. There is low quality evidence that melatonin improves sleep length after a night shift but not other sleep quality parameters. Both modafinil and armodafinil increase alertness and reduce sleepiness to some extent in employees who suffer from shift work sleep disorder but they are associated with adverse events. Caffeine plus naps reduces sleepiness during the night shift, but the quality of evidence is low. Based on one low quality trial, hypnotics did not improve sleep length and quality after a night shift.We need more and better quality trials on the beneficial and adverse effects and costs of all pharmacological agents that induce sleep or promote alertness in shift workers both with and without a diagnosis of shift work sleep disorder. We also need systematic reviews of their adverse effects.

Timing of food intake during simulated night shift impacts glucose metabolism: A controlled study.

PubMed

Grant, Crystal L; Coates, Alison M; Dorrian, Jillian; Kennaway, David J; Wittert, Gary A; Heilbronn, Leonie K; Pajcin, Maja; Della Vedova, Chris; Gupta, Charlotte C; Banks, Siobhan

2017-01-01

Eating during the night may increase the risk for obesity and type 2 diabetes in shift workers. This study examined the impact of either eating or not eating a meal at night on glucose metabolism. Participants underwent four nights of simulated night work (SW1-4, 16:00-10:00 h, <50 lux) with a daytime sleep opportunity each day (10:00-16:00 h, <3 lux). Healthy males were assigned to an eating at night (NE; n = 4, meals; 07:00, 19:00 and 01:30 h) or not eating at night (NEN; n = 7, meals; 07:00 h, 09:30, 16:10 and 19:00 h) condition. Meal tolerance tests were conducted post breakfast on pre-night shift (PRE), SW4 and following return to day shift (RTDS), and glucose and insulin area under the curve (AUC) were calculated. Mixed-effects ANOVAs were used with fixed effects of condition and day, and their interactions, and a random effect of subject identifier on the intercept. Fasting glucose and insulin were not altered by day or condition. There were significant effects of day and condition × day (both p < 0.001) for glucose AUC, with increased glucose AUC observed solely in the NE condition from PRE to SW4 (p = 0.05) and PRE to RTDS (p < 0.001). There was also a significant effect of day (p = 0.007) but not condition × day (p = 0.825) for insulin AUC, with increased insulin from PRE to RTDS in both eating at night (p = 0.040) and not eating at night (p = 0.006) conditions. Results in this small, healthy sample suggest that not eating at night may limit the metabolic consequences of simulated night work. Further study is needed to explore whether matching food intake to the biological clock could reduce the burden of type 2 diabetes in shift workers.

Diet quality and sleep quality among day and night shift nurses.

PubMed

Beebe, Deborah; Chang, Jen Jen; Kress, Kathleen; Mattfeldt-Beman, Mildred

2017-10-01

To determine whether night shift workers have a poorer diet quality and sleep quality when compared with day shift nurses. There is a dearth of research investigating the association between diet quality and sleep quality of day and night shift nurses. Data on nurses (n = 103) working either a day or night shift from two Midwestern hospitals were obtained from August 2015 to February 2016. The instruments used were the Diet History Questionnaire and the Pittsburg Sleep Quality Index. Independent samples t-tests were used to examine differences in diet and sleep quality by work shift schedule. There were no statistically significant differences between nurses working day or night shift and sleep quality (P = 0.0684), as well as diet quality (P = 0.6499). There was a significant difference between both body mass index (P = 0.0014) and exercise (P = 0.0020) with regard to diet quality. Body mass index and sleep quality were also significantly associated (P = 0.0032). Our study found no differences between day and night shift with regard to sleep and diet quality among nurses. Deliberate health initiatives and wellness programmes specifically targeting nurses are needed to increase knowledge about maintaining a healthy lifestyle while working as a nurse, whether it is day or night shift. © 2017 John Wiley & Sons Ltd.

The impact of shift and night work on health related quality of life of working women: findings from the Korea Health Panel.

PubMed

Kim, Woorim; Kim, Tae Hyun; Lee, Tae-Hoon; Choi, Jae Woo; Park, Eun-Cheol

2016-11-28

Night and shift work status has been associated with health related quality of life (HRQoL) in economically active women. This study aimed to investigate the association between night or shift work status and HRQoL of economically active women and to further analyze how marital status interplays in the objected relationship. Data were from the Korea Health Panel, 2011 to 2013. A total of 2238 working women were included for analysis. Work status was categorized into day work, night work, and rotating shift work and its association with HRQoL, measured using the EuroQol-5D (EQ-5D) index, was investigated using the generalized estimating equation (GEE) model. Compared to the day work reference group, the night work group (β: -0.9757, P = 0.0202) and the rotating shift work group (β: -0.7947, P = 0.0363) showed decreases in EQ-5D scores. This trend was maintained regardless of marital status, although decreases in health related quality of life were particularly pronounced among night shift workers with a spouse. Night and rotating shift work status was associated with HRQoL of economically active women as individuals working night and rotating shifts showed decreases in EQ-5D scores compared to individuals working day shifts. The findings of this study signify the importance of monitoring the HRQoL status of women working night and rotating shifts as these individuals may be comparatively vulnerable to reduced HRQoL.

Letter in reference to: "Short-term effects of night shift work on breast cancer risk: a cohort study of payroll data".

PubMed

Stevens, Richard G

2017-01-01

There are major flaws with the analyses in the Vistisen et al (1) cohort study examining if night shift work is a short-term risk factor for breast cancer. The crucial problem is the potential for exposure misclassification, which is very high. The authors' definition of day shift is "≥3 hours of work between 06:00-20:00 hours". This means that a worker on an 8-hour shift that begins at 03:00 hours would be classified as a day rather than night shift worker because he/she worked only two hours between 24:00-05:00 hours. Similarly, a second shifter might start work at 17:00 but not get off until 01:00 and yet still be classified as a "day shift" worker. This does not make sense as a baseline comparison group "unexposed" to work during the night hours. A sensible classification system would be to define "day shift" as any shift that begins after 07:00 and ends before 18:00 hours. This is straightforward and avoids all of the ambiguities inherent in the definition used by the authors. In addition, the authors claim that the "inception population" is less likely to have had past prior non-day work hours. However, this group has an average age of >35 years. It is inconceivable that all of these women were new graduates who started a public health sector job for the first time. Rather, the majority must surely have worked elsewhere for many years but then started in the regions covered only after 2006. This topic is too important, and this cohort too valuable, not to carefully define the baseline comparison group of "day workers" in a sensible manner. All the inferences rely crucially on this definition. The authors have the data to define the day-working baseline group in a way that avoids these obvious biases. That is why it is so frustrating that the authors chose to conduct the analyses as they did, with a highly flawed definition of "day work", when they could have done so much better. A highly flawed epidemiological report is worse than no report at all because it misleads the scientific community and the public. Reference 1. Vistisen HT, Garde AH, Frydenberg M, Christiansen P, Hansen ÅM, Hansen J, Bonde JPE, Kolstad HA. Short-term effects of night shift work on breast cancer risk: a cohort study of payroll data. Scand J Work Environ Health - online first. http://dx.doi.org/10.5271/sjweh.3603.

Organisational characteristics associated with shift work practices and potential opportunities for intervention: findings from a Canadian study.

PubMed

Hall, Amy L; Smit, Andrea N; Mistlberger, Ralph E; Landry, Glenn J; Koehoorn, Mieke

2017-01-01

Shift work is a common working arrangement with wide-ranging implications for worker health. Organisational determinants of shift work practices are not well characterised; such information could be used to guide evidence-based research and best practices to mitigate shift work's negative effects. This exploratory study aimed to describe and assess organisational-level determinants of shift work practices thought to affect health, across a range of industry sectors. Data on organisational characteristics, shift work scheduling, provision of shift work education materials/training to employees and night-time lighting policies in the workplace were collected during phone interviews with organisations across the Canadian province of British Columbia. Relationships between organisational characteristics and shift work practices were assessed using multivariable logistic regression models. The study sample included 88 participating organisations, representing 30 700 shift workers. Long-duration shifts, provision of shift work education materials/training to employees and night-time lighting policies were reported by approximately one-third of participating organisations. Odds of long-duration shifts increased in larger workplaces and by industry. Odds of providing shift work education materials/training increased in larger workplaces, in organisations reporting concern for shift worker health and in organisations without seasonal changes in shift work. Odds of night-time lighting policies in the workplace increased in organisations reporting previous workplace accidents or incidents that occurred during non-daytime hours, site maintenance needs and client service or care needs. This study points to organisational determinants of shift work practices that could be useful for targeting research and workplace interventions. Results should be interpreted as preliminary in an emerging body of literature on shift work and health. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Breast cancer risk and night shift work in a case-control study in a Spanish population.

PubMed

Papantoniou, Kyriaki; Castaño-Vinyals, Gemma; Espinosa, Ana; Aragonés, Nuria; Pérez-Gómez, Beatriz; Ardanaz, Eva; Altzibar, Jone Miren; Sanchez, Vicente Martin; Gómez-Acebo, Inés; Llorca, Javier; Muñoz, David; Tardón, Adonina; Peiró, Rosana; Marcos-Gragera, Rafael; Pollan, Marina; Kogevinas, Manolis

2016-09-01

Epidemiologic and animal data indicate that night shift work might increase the risk for breast cancer. We evaluated the association of night work with different clinical types of breast cancer in a population based case-control study (MCC-Spain study) taking into account chronotype, an individual characteristic that may relate to night shift work adaptation. Lifetime occupational history was assessed by face-to-face interviews and shift work information was available for 1708 breast cancer cases and 1778 population controls from 10 Spanish regions, enrolled from 2008 to 2013. We evaluated three shift work domains, including shift work type (permanent vs rotating), lifetime cumulative duration and frequency. We estimated odds ratios (OR) for night work compared to day work using unconditional logistic regression models adjusting for confounders. Having ever worked permanent or rotating night shift was associated with an increased risk for breast cancer compared to day workers [odds ratio (OR) 1.18; 95 % CI 0.97, 1.43]. Chronotype was differentially associated with breast cancer depending on the duration of night shift work. Risk was higher in women with invasive tumors (OR 1.23; 95 % CI 1.00, 1.51) and for estrogen and progestagen positive tumors among premenopausal women (OR 1.44; 95 % CI 1.05, 1.99). Having ever performed night shift was associated with a small increased risk for breast cancer and especially in subgroups of women with particular hormone related characteristics.

Association of Rotating Night Shift Work with BMI and Abdominal Obesity among Nurses and Midwives.

PubMed

Peplonska, Beata; Bukowska, Agnieszka; Sobala, Wojciech

2015-01-01

Mounting epidemiological evidence suggests that night shift work may contribute to the etiology of increased body weight. The present study aimed to examine association between rotating night shift work and body mass index (BMI), and abdominal adiposity respectively among nurses and midwives. A cross-sectional study was conducted among 724 female nurses and midwives, aged 40-60 years (354 rotating night shift and 370 daytime workers) in Łódź, Poland, between 2008 and 2011. Information about occupational history and potential confounders was collected during personal interviews. Anthropometric measurements of body weight, height, waist (WC) and hip (HC) circumference were made, and body mass index (BMI), waist to hip ratio (WHR) and waist to height ratio (WHtR) were calculated. GLM regression models and multinomial logit regression models were fitted to explore the association between night shift work and anthropometric parameters, with adjustment for age, body silhouette at age 20, current smoking status, packyears, marital status, and menopausal hormone therapy use. Cumulative night shift work showed significant associations with BMI, WC, HC and WHtR, with BMI increasing by 0.477 kg/m2 per 1000 night duties and by 0.432 kg/m2 per 10000 night shift hours, WC increasing respectively by 1.089 cm and 0.99 cm, and HC by 0.72 cm and WHtR by 0.007 cm for both metrics. Both current and cumulative night work was associated with obesity (BMI≥30kg/m2), with OR=3.9 (95%CI:1.5-9.9), in women reporting eight or more night shifts per month. The results of the study support the previously reported relations between night shift work and development of obesity.

Association of Rotating Night Shift Work with BMI and Abdominal Obesity among Nurses and Midwives

PubMed Central

Peplonska, Beata; Bukowska, Agnieszka; Sobala, Wojciech

2015-01-01

Background Mounting epidemiological evidence suggests that night shift work may contribute to the etiology of increased body weight. The present study aimed to examine association between rotating night shift work and body mass index (BMI), and abdominal adiposity respectively among nurses and midwives. Methods A cross-sectional study was conducted among 724 female nurses and midwives, aged 40-60 years (354 rotating night shift and 370 daytime workers) in Łódź, Poland, between 2008 and 2011. Information about occupational history and potential confounders was collected during personal interviews. Anthropometric measurements of body weight, height, waist (WC) and hip (HC) circumference were made, and body mass index (BMI), waist to hip ratio (WHR) and waist to height ratio (WHtR) were calculated. GLM regression models and multinomial logit regression models were fitted to explore the association between night shift work and anthropometric parameters, with adjustment for age, body silhouette at age 20, current smoking status, packyears, marital status, and menopausal hormone therapy use. Results Cumulative night shift work showed significant associations with BMI, WC, HC and WHtR, with BMI increasing by 0.477 kg/m2 per 1000 night duties and by 0.432 kg/m2 per 10000 night shift hours, WC increasing respectively by 1.089 cm and 0.99 cm, and HC by 0.72 cm and WHtR by 0.007 cm for both metrics. Both current and cumulative night work was associated with obesity (BMI≥30kg/m2), with OR=3.9 (95%CI:1.5-9.9), in women reporting eight or more night shifts per month. Conclusion The results of the study support the previously reported relations between night shift work and development of obesity. PMID:26196859

Alteration in eating habits among shift workers of a poultry processing plant in southern Brazil.

PubMed

de Freitas, Elisângela da Silva; Canuto, Raquel; Henn, Ruth Liane; Olinto, Beatriz Anselmo; Macagnan, Jamile Block Araldi; Pattussi, Marcos Pascoal; Busnello, Fernanda Michelin; Olinto, Maria Teresa Anselmo

2015-08-01

The relationship between shift work and the eatinghabits of workers was investigated in a slaughterhouse in southern Brazil. It involved a cross-sectional study with 1,206 workers of both sexes between 18 and 50 years of age. A standardized questionnaire was used to gather demographic, socioeconomic, work shift and eating habit information. The shift of work was categorized into daytime and nighttime, based on the starting and ending times of the shift. The eating habits of workers were evaluated as follows: number and type of meals eaten during the 24 hours of a normal day, the inappropriateness of the hoursof these meals and the dietaryrisk score. This was built on the risk score of the weekly consumption of 13 food items. After adjusting for potential confounders, non-Caucasian and younger male workers were more likely to manifest eating risk habits. Nighttimeshift workers consumed ahigher number of meals/day with greater inappropriateness of meal times than daytimeshift workers. The night shift can negatively influence the eating habits of workers of that shift.

Napping during the night shift and recovery after work among hospital nurses1

PubMed Central

Palermo, Thaís Aparecida de Castro; Rotenberg, Lúcia; Zeitoune, Regina Célia Gollner; Silva-Costa, Aline; Souto, Ester Paiva; Griep, Rosane Härter

2015-01-01

OBJECTIVE: To analyze the association between the length of napping during the night shift and the recovery after work among nurses. METHOD: Cross-sectional epidemiological study involving 1940 nurses from 18 public hospitals in the City of Rio de Janeiro. A multidimensional and self-applied questionnaire was used with information about health, sociodemographic and occupational characteristics, health-related behaviors and housework. Multiple logistic regression was applied to identify the association, adjusted for confounding variables. RESULTS: The gross analyses showed 44%, 127% and 66% higher chances of a high level of recovery after work for nurses who sleep up to two hours, between 2.1 and 3 hours and 3.1 hours or more, respectively, when compared to the nurses who do not sleep. After adjusting for confounding variables, the association only continues significant for the group that sleeps 2.1 to 3 hours during the night shift (OR=1.79; 95%CI=1.33-2.41). CONCLUSION: The association between the length of napping and the high level of recovery after work, confirmed in the present results, can be included in the studies that aim to support more appropriate policies aimed at improving the workers' work, life and health conditions, not only in nursing, but night-shift workers in general. PMID:25806639

The role of experience in night work: Lessons from two ergonomic studies.

PubMed

Pueyo, Valérie; Toupin, Cathy; Volkoff, Serge

2011-01-01

The purpose of this article is to analyze some connections between experience, health and work, especially in the field of night work. As a result of the baby boom, the proportion of elderly workers is steadily increasing, while at the same time many workers are reaching retirement age and being replaced by younger people. And, in the same time, there is an overall gradual increase in shift work and night work. To our knowledge, worker experience has not been extensively studied in this context. This was our focus in studying work activity in two very different situations, in a hospital and in a steel industry. In these two studies we observed that the experienced workers endeavor to plan ahead, especially at night. They do this to limit fatigue and to avoid emergencies and ensure that work is stress-free and as far as possible under control. But experience not only brings workers to plan ahead, it also enables them to do so, thanks to the resources it confers: gaining familiarity with tasks and acquiring the ability to identify critical situations, gaining knowledge about themselves and awareness of situations that cause difficulty; and gaining a better overview of the collective aspects of their work and of ways to share tasks or obtain assistance. They are able to undertake these strategies thanks to specific skills and capacities they have built along their professional career, which notably leads them to find the best trade-off between several goals, possibly contradictory. Such experience is especially valuable at night, when the worker is tired, and when there are fewer supervisors present. This experience can only be gained, however, if the work environment fosters its acquisition and provides an opportunity to make use of it, especially during the night shift and especially with respect to planning tasks ahead of time. Copyright © 2010 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Night work and health status of nurses and midwives. cross-sectional study.

PubMed

Burdelak, Weronika; Bukowska, Agnieszka; Krysicka, Jolanta; Pepłońska, Beata

2012-01-01

The aim of this study was to assess the association between night shift work and the prevalence of diseases and conditions among nurses and midwives. The study included 725 subjects (354 working on night shifts and 371 working only during the day). The data were collected via an interview based on the "Standard Shiftwork Index". We analyzed the frequency of diseases and conditions and the relative risk expressed as the odds ratio (adjusted for important confounding factors). The most common diseases in the study population were chronic back pain (47.2%), hypertension (24.5%) and thyroid diseases (21.2%). We found no statistically significant increased relative risk of any diseases and conditions among the night shift nurses, compared to the day shift ones. The duration of the work performed on night shifts was significantly associated with the relative risk of thyroid diseases--increased almost two times in the women working for 15 or more years in such system (p for trend: 0.031). The analysis showed the significantly increased (more than eight times higher) relative risk of feet swelling in the women with 8 or more night duties per month, compared to the women having fewer night shifts. We did not observe a higher frequency of diseases in the night shift nurses, compared to the day shift nurses. These results may be related to the so-called "Healthy Worker Effect". There is a need for further long-term observational studies in the populations of nurses.

Dark matters: effects of light at night on metabolism.

PubMed

Nelson, Randy J; Chbeir, Souhad

2018-05-11

Life on earth has evolved during the past several billion years under relatively bright days and dark night conditions. The wide-spread adoption of electric lights during the past century exposed animals, both human and non-human, to significant light at night for the first time in their evolutionary history. Endogenous circadian clocks depend on light to entrain to the external daily environment and seasonal rhythms depend on clear nightly melatonin signals to assess time of year. Thus, light at night can derange temporal adaptations. Indeed, disruption of naturally evolved light-dark cycles results in several physiological and behavioural changes with potentially serious implications for physiology, behaviour and mood. In this review, data from night-shift workers on their elevated risk for metabolic disorders, as well as data from animal studies will be discussed. Night-shift workers are predisposed to obesity and dysregulated metabolism that may result from disrupted circadian rhythms. Although studies in human subjects are correlative, animal studies have revealed several mechanisms through which light at night may exert its effects on metabolism by disrupting circadian rhythms that are associated with inflammation, both in the brain and in the periphery. Disruption of the typical timing of food intake is a key effect of light at night and subsequent metabolic dysregulation. Strategies to avoid the effects of light at night on body mass dysregulation should be pursued.

Health-related interventions among night shift workers: a critical review of the literature.

PubMed

Neil-Sztramko, Sarah E; Pahwa, Manisha; Demers, Paul A; Gotay, Carolyn C

2014-11-01

Associations between shift work and chronic disease have been observed, but relatively little is known about how to mitigate these adverse health effects. This critical review aimed to (i) synthesize interventions that have been implemented among shift workers to reduce the chronic health effects of shift work and (ii) provide an overall evaluation of study quality. MeSH terms and keywords were created and used to conduct a rigorous search of MEDLINE, CINAHL, and EMBASE for studies published on or before 13 August 2012. Study quality was assessed using a checklist adapted from Downs & Black. Of the 5053 articles retrieved, 44 met the inclusion and exclusion criteria. Over 2354 male and female rotating and permanent night shift workers were included, mostly from the manufacturing, healthcare, and public safety industries. Studies were grouped into four intervention types: (i) shift schedule; (ii) controlled light exposure; (iii) behavioral; and, (iv) pharmacological. Results generally support the benefits of fast-forward rotating shifts; simultaneous use of timed bright light and light-blocking glasses; and physical activity, healthy diet, and health promotion. Mixed results were observed for hypnotics. Study quality varied and numerous deficiencies were identified. Except for hypnotics, several types of interventions reviewed had positive overall effects on chronic disease outcomes. There was substantial heterogeneity among studies with respect to study sample, interventions, and outcomes. There is a need for further high-quality, workplace-based prevention research conducted among shift workers.

Occupational stress experienced by residents and faculty physicians on night shifts.

PubMed

Tür, Feriyde Çalişkan; Toker, İbrahim; Şaşmaz, Cafer Tayyar; Hacar, Serkan; Türe, Burcu

2016-03-22

Occupational stress is an undesired factor causing discomfort for healthcare workers. Stressors in work can lead to dissatisfaction and in turn, this may affect patient care adversely. The aim of this study was to evaluate the occupational stress among residents and faculty physicians of various medical specialties working night shifts. Residents and faculty physicians working night shifts in the emergency departments, medical and surgical wards were questioned with Swedish Demand Control Support Questionnaire. Also, various factors (specialty, marital status, sex, number of patients during a typical shift, number of night shifts per month, decision about career making in that specialty, having chronic disease and/or sleep problem) originated from social life or working conditions were investigated that could affect the demand, job-control and job strain model. Of the 108 participants, the mean age was 31 ± 6 years, 40.7% were female, and 78.7% were residents. Job strain was similar among the three physician groups (p > 0.05). Job control and social support was found to be lower among residents while job stress was higher. The social support-scores were lower in residents who were responsible for more than 60 patients, and who had a chronic disease. The demand-scores were lower in faculty physicians who worked 1 to 4 night shifts per month. Job strain was higher in residents with respect to faculty physicians. Stress and psychosocial risk factors are considered critical issues in the field of occupational health. Workload and job stress are stated as predictors of workers' health, productivity, and motivation. We found a few job stressors by physician working night shifts such as number of taken care of patient, having chronic disease. But, these physicians were significantly residents, due to their high workload sense. Interestingly, job stress was not more by emergency physicians than others. Job strain was found to be higher among the residents as compared to the faculty physicians. Job strain was not significantly different among the physicians of emergency medicine than the physicians of the other specialties working night shifts.

A prospective cohort study of shift work and the risk of death from pancreatic cancer in Japanese men.

PubMed

Lin, Yingsong; Ueda, Junko; Yagyu, Kiyoko; Kurosawa, Michiko; Tamakoshi, Akiko; Kikuchi, Shogo

2013-07-01

There is mounting evidence that shift work involving night work increases cancer risk. We examined the relationship between working rotating shifts and the risk of death from pancreatic cancer on the basis of data from the Japanese Collaborative Cohort Study (JACC Study). The present analysis was restricted to 22,224 men who were 40-65 years of age at baseline (1988-1990) and who reported working full time or were self-employed in the JACC Study. The subjects were followed through 31 December 2009. Information on occupation and lifestyle factors was collected using a self-administered questionnaire. The Cox proportional hazards model was used to estimate the relative risk (RR) and 95% confidence interval (CI) for the risk of death from pancreatic cancer in relation to shift work. During the follow-up period, 127 pancreatic cancer deaths were observed. Overall, we found no statistically significant increase in the risk of death from pancreatic cancer associated with rotating shift work. As compared to day-shift workers, the RRs were 0.83 (95% CI 0.43-1.60) for rotating shift workers and 0.61 (95% CI 0.22-1.60) for fixed night-shift workers, after adjustment for potential confounding factors. The multivariable-adjusted RR was 1.34 (95% CI 0.66-2.75) among rotating shift workers in the analysis restricted to men who reported working full time at baseline. Our data did not support the hypothesis that shift work is significantly associated with the risk of death from pancreatic cancer in this cohort of Japanese men.

The influence of shift work on cognitive functions and oxidative stress.

PubMed

Özdemir, Pınar Güzel; Selvi, Yavuz; Özkol, Halil; Aydın, Adem; Tülüce, Yasin; Boysan, Murat; Beşiroğlu, Lütfullah

2013-12-30

Shift work influences health, performance, activity, and social relationships, and it causes impairment in cognitive functions. In this study, we investigated the effects of shift work on participants' cognitive functions in terms of memory, attention, and learning, and we measured the effects on oxidative stress. Additionally, we investigated whether there were significant relationships between cognitive functions and whole blood oxidant/antioxidant status of participants. A total of 90 health care workers participated in the study, of whom 45 subjects were night-shift workers. Neuropsychological tests were administered to the participants to assess cognitive function, and blood samples were taken to detect total antioxidant capacity and total oxidant status at 08:00. Differences in anxiety, depression, and chronotype characteristics between shift work groups were not significant. Shift workers achieved significantly lower scores on verbal memory, attention-concentration, and the digit span forward sub-scales of the Wechsler Memory Scale-Revised (WMS-R), as well as on the immediate memory and total learning sub-scales of the Auditory Verbal Learning Test (AVLT). Oxidative stress parameters were significantly associated with some types of cognitive function, including attention-concentration, recognition, and long-term memory. These findings suggest that night shift work may result in significantly poorer cognitive performance, particularly working memory. © 2013 Elsevier Ireland Ltd. All rights reserved.

[Tobacco and alcohol consumption according to workday in Spain].

PubMed

García-Díaz, Vanesa; Fernández-Feito, Ana; Arias, Lucía; Lana, Alberto

2015-01-01

To examine the association between smoking and alcohol consumption and the type of working day in the Spanish population Cross-sectional study among employees residing in Spain aged >18 years (N=8,736). We took data from the National Health Survey (2011-2012). Information was collected on the type of working day (morning, afternoon, evening, part-time, reduced hours, and shift-work) and smoking and drinking habits. Demographic characteristics and health- and work-related factors were also taken into account. Adjusted odds ratios (aOR) and 95% confidence intervals (95%CI) were calculated through log-binomial regressions. Among respondents, 32.1% smoked regularly, especially those working the night shift (43.5%). Moderate alcohol consumption was found in 54.8% of workers and excessive consumption in 1.5%. Most of the moderate and heavy drinkers worked part-time, with 57.6% and 1.8% respectively. The aOR of being a smoker was higher among night workers (OR=1.58; 95% CI: 1.01-2.46). None of the work shifts were significantly associated with alcohol consumption. Night shift work was associated with regular smoking. This collective of workers should be monitored closely by occupational health services and regularly undergo programs to control tobacco consumption and smoking-related diseases. Additional research to elucidate the reasons for this association could help to achieve preventive and therapeutic success. Copyright © 2015 SESPAS. Published by Elsevier Espana. All rights reserved.

Rotating night shift work and physical activity of nurses and midwives in the cross-sectional study in Łódź, Poland.

PubMed

Peplonska, Beata; Bukowska, Agnieszka; Sobala, Wojciech

2014-12-01

Shift work have been thought to restrict participation in leisure time activities, but the knowledge about physical activity in rotating night shift nurses has been limited so far. We investigated the associations between the rotating night shift work and physical activity using data from a cross-sectional study among nurses and midwives. This study included 354 nurses and midwives (aged 40-60) currently working rotating night shifts and 371 ones working days only. The information on the work characteristics and potential covariates was collected via a personal interview. Weight and height were measured and BMI was calculated. Physical activity was assessed according to the international questionnaire on physical activity - IPAQ, and four domains: leisure time, occupational, transport related and household were analyzed. Women who reported none leisure time activity were defined as recreationally "inactive". The associations were examined with multiple linear or logistic regression models adjusted for age, season of the year, number of full term births, marital status and BMI. Total and occupational physical activity was significantly higher among nurses working rotating night shifts. However, leisure time activity was significantly affected among rotating night shift nurses and midwives, compared to women working during the days only, with increased odds ratio for recreational "inactivity" (OR = 1.57, 95% CI: 1.11-2.20). Rotating night shift work among nurses and midwives is associated with higher occupational physical activity but lower leisure time activity. Initiatives supporting exercising among night shift workers are recommended.

Health Effects of Shift Work

PubMed Central

LaDou, Joseph

1982-01-01

More than 13.5 million American workers, close to 20 percent of the work force, are assigned to evening or night shifts. In some industries such as automobile, petrochemical and textile manufacturing the proportion of shift workers is greater than 50 percent. As the popularity of shift work and other “alternative work schedules” grows, concern is increasing over the disturbance created in the lives of workers and their families by these economically and socially useful innovations. Twenty percent of workers are unable to tolerate shift work. Daily physiologic variations termed circadian rhythms are interactive and require a high degree of phase relationship to produce subjective feelings of wellbeing. Disturbance of these activities, circadian desynchronization, whether from passage over time zones or from shift rotation, results in health effects such as disturbance of the quantity and quality of sleep, disturbance of gastrointestinal and other organ system activities, and aggravation of diseases such as diabetes mellitus, epilepsy and thyrotoxicosis. Worker selection can reduce the number of health problems resulting from shift work. The periodic examination of shift workers is recommended. PMID:6962577

The effect of shift rotation on employee cortisol profile, sleep quality, fatigue, and attention level: a systematic review.

PubMed

Niu, Shu-Fen; Chung, Min-Huey; Chen, Chiung-Hua; Hegney, Desley; O'Brien, Anthony; Chou, Kuei-Ru

2011-03-01

Disrupted circadian rhythm, especially working night duty together with irregular sleep patterns, sleep deprivation, and fatigue, creates an occupational health risk associated with diminished vigilance and work performance. This study reviewed the effect of shift rotations on employee cortisol profile, sleep quality, fatigue, and attention level. Researchers conducted a systematic review of relevant articles published between 1996 and 2008 that were listed on the following databases: SCOPUS, OVID, Blackwell Science, EBSCO Host, PsycINFO, Cochrane Controlled Trials Register, and CEPS. A total of 28 articles were included in the review. Previous research into the effects of shift work on cortisol profiles, sleep quality, fatigue, and attention used data assessed at evidence Levels II to IV. Our systematic review confirmed a conflict between sleep-wake cycle and light-dark cycle in night work. Consequences of circadian rhythm disturbance include disruption of sleep, decreased vigilance, general feeling of malaise, and decreased mental efficiency. Shift workers who sleep during the day (day sleepers) experience cortisol secretion increases, which diminish the healing power of sleep and enjoy 1 to 4 hours less sleep on average than night sleepers. Sleep debt accumulation results in chronic fatigue. Prolonged fatigue and inadequate recovery result in decreased work performance and more incidents. Rotation from day shift to night shift and its effect on shift workers was a special focus of the articles retained for review. Disturbed circadian rhythm in humans has been associated with a variety of mental and physical disorders and may negatively impact on work safety, performance, and productivity.

[The operational role of the occupational health physician in the assessment and management of health risks related to night risks].

PubMed

Mucci, Nicola; Giorgi, Gabriele; Gonnelli, Irene Margherita; Garbarino, Sergio; Cupelli, Vincenzo; Arcangelil, Giulio

2016-01-01

The operational role of the occupational health physician in the assessment and management of health risks related to night work. Night work, in the last 30-40 years, has been extended to almost all areas of employment. The potential effects on workers' health--related to the disruption of circadian rhythms--are now well defined and studied in the Literature. All issues about the protection of safety and health for night workers are governed by the Italian Legislative Decree no. 66/2003 and subsequent amendments. The management of night work hasn't been included into the main Law on Occupational Safety and Health (Italian Legislative Decree no. 81/2008 and subsequent amendments) and a coordination between the two disciplines is desirable. The occupational health physician, as a global consultant for the protection of all health issues into a company, has to evaluate the potential effects of night work on health, both individually and as a group of workers. In this way, the physician may use either traditional tools (history, physical examination, blood tests) or innovative tools (questionnaires, health promotion programs, interventions on shift schedules). In the management of night work is useful to employ schedules that respect both psychophysical integrity and social welfare of workers and the needs of the production. The occupational health physician plays a significant role in information and training of workers, both individually and as a group of workers, and in the organization of health promotion programs (whit a voluntary participation by the workers).

Night-shift work and hematological cancers: a population based case-control study in three Nordic countries.

PubMed

Talibov, Madar; Pukkala, Eero; Martinsen, Jan Ivar; Tryggvadottir, Laufey; Weiderpass, Elisabete; Hansen, Johnni

2018-05-01

Objective The aim of this case-control study was to assess the effect of night-shift work on the risk of hematological cancers. Methods The study included 39 371 leukemia, 56 713 non-Hodgkin lymphoma, 9322 Hodgkin lymphoma, and 26 188 multiple myeloma cases diagnosed between 1961 and 2005 in Finland, Sweden, and Iceland. Five controls for each case were selected from the Nordic Occupational Cancer Study (NOCCA) cohort, matched by year of birth, sex and country. Night-shift exposure was assessed by using the NOCCA job-exposure matrix (JEM). Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated from conditional logistic regression models. Results Overall, night work was not associated with a risk of hematological cancers. We observed a small but non-significantly increased risk for leukemia (OR 1.07, 95% CI 0.99-1.16), especially for acute myeloid leukemia (OR 1.15, 95% CI 0.97-1.36) among workers exposed to a high level of cumulative night work exposure. Night work exposure was not associated with lymphatic cancers and multiple myeloma. Conclusion This study did not support associations between night-shift work and hematological cancers.

Shift work at a modern offshore drilling rig.

PubMed

Rodrigues, V F; Fischer, F M; Brito, M J

2001-12-01

The oil and gas exploration and production offshore units are classified as hazardous installations. Work in these facilities is complex, confined and associated with a wide range of risks. The continuous operation is secured by various shift work patterns. The objective of this study was to evaluate how offshore drilling workers perceived shift work at high seas and its impacts on their life and working conditions. The main features of the studied offshore shift work schedules are: long time on board (14 to 28 days), extended shifts (12 hours or more per day), slow rotation (7 to 14 days in the same shift), long sequence of days on the night shift (7 to 14 days in a row) and the extra-long extended journey (18 hours) on shift change and landing days. Interviews revealed a wide range of stressors caused by the offshore shift work, as well as difficulties to conciliate work with family life. It was observed that changes of the family model, leading to role conflicts and social isolation, work in a hazardous environment, perceiving poor sleep when working at night shifts and the imbalance between the expected and actual rewards are the major stressors for the offshore drilling workers.

The impact of shift work and organizational work climate on health outcomes in nurses.

PubMed

von Treuer, Kathryn; Fuller-Tyszkiewicz, Matthew; Little, Glenn

2014-10-01

Shift workers have a higher rate of negative health outcomes than day shift workers. Few studies however, have examined the role of difference in workplace environment between shifts itself on such health measures. This study investigated variation in organizational climate across different types of shift work and health outcomes in nurses. Participants (n = 142) were nursing staff from a metropolitan Melbourne hospital. Demographic items elicited the type of shift worked, while the Work Environment Scale and the General Health Questionnaire measured organizational climate and health respectively. Analysis supported the hypotheses that different organizational climates occurred across different shifts, and that different organizational climate factors predicted poor health outcomes. Shift work alone was not found to predict health outcomes. Specifically, permanent night shift workers had significantly lower coworker cohesion scores compared with rotating day and evening shift workers and significantly higher managerial control scores compared with day shift workers. Further, coworker cohesion and involvement were found to be significant predictors of somatic problems. These findings suggest that differences in organizational climate between shifts accounts for the variation in health outcomes associated with shift work. Therefore, increased workplace cohesion and involvement, and decreased work pressure, may mitigate the negative health outcomes of shift workers. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Night shift work and lung cancer risk among female textile workers in Shanghai, China.

PubMed

Kwon, Paul; Lundin, Jessica; Li, Wenjin; Ray, Roberta; Littell, Christopher; Gao, Daoli; Thomas, David B; Checkoway, Harvey

2015-01-01

In 2007, the International Agency for Research on Cancer classified shift work that involves circadian disruption as a probable human carcinogen. Suppression of the anti-neoplastic hormone, melatonin, is a presumed mechanism of action. We conducted a case-cohort study nested within a cohort of 267,400 female textile workers in Shanghai, China. Newly diagnosed lung cancer cases (n = 1451) identified during the study period (1989-2006) were compared with an age-stratified subcohort (n = 3040). Adjusting for age, smoking, parity, and endotoxin exposure, relative risks [hazard ratios (HRs)] were estimated by Cox regression modeling to assess associations with cumulative years and nights of rotating shift work. Results did not consistently reveal any increased risk of lung cancer among rotating shift work or statistically significant trends for both cumulative years (HR 0.82, 95% CI 0.66 to 1.02; P(trend) = 0.294) and nights (HR 0.81, 95% CI 0.65 to 1.00; P(trend) = 0.415). Further analyses imposing 10- and 20-year lag times for disease latency also revealed similar results. Contrary to the initial hypothesis, rotating nighttime shift work appears to be associated with a relatively reduced lung cancer risk although the magnitude of the effect was modest and not statistically significant.

Light at Night and Measures of Alertness and Performance: Implications for Shift Workers.

PubMed

Figueiro, Mariana G; Sahin, Levent; Wood, Brittany; Plitnick, Barbara

2016-01-01

Rotating-shift workers, particularly those working at night, are likely to experience sleepiness, decreased productivity, and impaired safety while on the job. Light at night has been shown to have acute alerting effects, reduce sleepiness, and improve performance. However, light at night can also suppress melatonin and induce circadian disruption, both of which have been linked to increased health risks. Previous studies have shown that long-wavelength (red) light exposure increases objective and subjective measures of alertness at night, without suppressing nocturnal melatonin. This study investigated whether exposure to red light at night would not only increase measures of alertness but also improve performance. It was hypothesized that exposure to both red (630 nm) and white (2,568 K) lights would improve performance but that only white light would significantly affect melatonin levels. Seventeen individuals participated in a 3-week, within-subjects, nighttime laboratory study. Compared to remaining in dim light, participants had significantly faster reaction times in the GO/NOGO test after exposure to both red light and white light. Compared to dim light exposure, power in the alpha and alpha-theta regions was significantly decreased after exposure to red light. Melatonin levels were significantly suppressed by white light only. Results show that not only can red light improve measures of alertness, but it can also improve certain types of performance at night without affecting melatonin levels. These findings could have significant practical applications for nurses; red light could help nurses working rotating shifts maintain nighttime alertness, without suppressing melatonin or changing their circadian phase. © The Author(s) 2015.

Pharmacological interventions for sleepiness and sleep disturbances caused by shift work.

PubMed

Liira, Juha; Verbeek, Jos H; Costa, Giovanni; Driscoll, Tim R; Sallinen, Mikael; Isotalo, Leena K; Ruotsalainen, Jani H

2015-02-01

Shift work results in sleep-wake disturbances, which cause sleepiness during night shifts and reduce sleep length and quality in daytime sleep after the night shift. In its serious form it is also called shift work sleep disorder. Various pharmacological products are used to ameliorate symptoms of sleepiness or poor sleep length and quality. To evaluate the effects of pharmacological interventions to reduce sleepiness or to improve alertness at work and decrease sleep disturbances whilst of work, or both, in workers undertaking shift work. We searched CENTRAL, MEDLINE, EMBASE, PubMed and PsycINFO up to 20 September 2013 and ClinicalTrials.gov up to July 2013. We also screened reference lists of included trials and relevant reviews. We included all eligible randomised controlled trials (RCTs), including cross-over RCTs, of pharmacological products among workers who were engaged in shift work (including night shifts) in their present jobs and who may or may not have had sleep problems. Primary outcomes were sleep length and sleep quality while of work, alertness and sleepiness, or fatigue at work. Two authors independently selected studies, extracted data and assessed risk of bias in included trials. We performed meta-analyses where appropriate. We included 15 randomised placebo-controlled trials with 718 participants. Nine trials evaluated the effect of melatonin and two the effect of hypnotics for improving sleep problems. One trial assessed the effect of modafinil, two of armodafinil and one examined caffeine plus naps to decrease sleepiness or to increase alertness.

Oxidative stress and insulin resistance in policemen working shifts.

PubMed

Demir, Irfan; Toker, Aysun; Zengin, Selcuk; Laloglu, Esra; Aksoy, Hulya

2016-04-01

Shift work is a work schedule involving irregular or unusual hours, compared to those of a normal daytime work schedule. In developed countries, night shift work is very common. In several cities of our country, 12/24 shift system is implemented in police organization. While night shift work composes half of the 20 shift in a month, in ergonomic shift system, an alternative shift schedule, shift work can be performed in three shifts in a day. In this study, we aimed to investigate the effects of 12/24 shift work system on insulin resistance and oxidative stress and systemic inflammation. Two hundred and four 12/24 shift workers (age 44.3 ± 5.6 years) and 193 ergonomic shift workers (age 42.6 ± 5.5 years) were included to study. Serum oxidized LDL (ox-LDL), neutrophil gelatinase lipocalin-2 (NGAL) as oxidative stress markers, glucose, insulin, ferritin, high-sensitive C-reactive protein (hsCRP) and erythrocyte sedimentation rate values were measured. Homeostasis model assessment for insulin resistance (HOMA-IR) was calculated to evaluate insulin resistance. Serum ox-LDL, HOMA-IR, hsCRP and NGAL levels in 12/24 shift system were found to be significantly higher compared with ergonomic shift workers (p < 0.0001, p = 0.02, p = 0.03, p = 0.02, respectively). When evaluated all subjects, weak but significant correlation was found between HOMA-IR with ox-LDL (r = 0.12, p = 0.01), hsCRP (r = 0.17, p = 0.001) and ferritin (r = 0.15, r = 0.003). Also in 12/24 shift work group, there were significant correlations between HOMA-IR with hsCRP (r = 0.17, p = 0.01) and ferritin (r = 0.25, p = 0.0001). It may be concluded that 12/24 shift system might give rise to insulin resistance and oxidative stress. Additionally, workers in this system may under risk of systemic inflammatory response. Working hours must be arranged in accordance with the physiological rhythm.

Assessing and managing the shift work disorder in healthcare workers.

PubMed

D'Ettorre, Gabriele; Pellicani, Vincenza; Greco, Mariarita; Mazzotta, Mauro; Vullo, Annamaria

2018-02-20

Shift work disorder (SWD) is a major concern for both healthcare workers (HCWs) employed in hospital wards and healthcare organizations. The consequences of SWD may lead to increased service costs and lower standards of care. To identify and evaluate the latest developments in assessing and managing the occupational risk of SWD in shift-HCWs through a search of the literature published in the last five years. We performed a search of the literature starting from June 2012, using MEDLINE/Pubmed. The articles were reviewed and categorized into one or more of the following categories based on their subject matter: Risk assessment, Risk management, Occurrence rates. A total of 25 publications matched the inclusion criteria. The topics discussed, in order of frequency (from the highest to the lowest), were: "Risk Assessment" (84%), "Occurrence Rates" (64%) and "Risk Management" (48%). Number of nights worked per year, long night-time working hours, frequent missing of nap opportunities during night-shift, quick returns and unhealthy workplace were found as organizational determinants of SWD that should be prioritized in the risk assessment of shift work in the healthcare sector. Organizational interventions targeted on both healthy shift-work scheduling and improvement of the workplace safety are proposed to moderate the occurrence of SWD and, consequently, to ensure HCWs' wellness and suitable standards of patient care. Further studies aimed to investigate the effectiveness of such interventions in minimizing SWD occurrence are needed.

The impact of shift work on the psychological and physical health of nurses in a general hospital: a comparison between rotating night shifts and day shifts.

PubMed

Ferri, Paola; Guadi, Matteo; Marcheselli, Luigi; Balduzzi, Sara; Magnani, Daniela; Di Lorenzo, Rosaria

2016-01-01

Shift work is considered necessary to ensure continuity of care in hospitals and residential facilities. In particular, the night shift is one of the most frequent reasons for the disruption of circadian rhythms, causing significant alterations of sleep and biological functions that can affect physical and psychological well-being and negatively impact work performance. The aim of this study was to highlight if shift work with nights, as compared with day work only, is associated with risk factors predisposing nurses to poorer health conditions and lower job satisfaction. This cross-sectional study was conducted from June 1, 2015 to July 31, 2015 in 17 wards of a general hospital and a residential facility of a northern Italian city. This study involved 213 nurses working in rotating night shifts and 65 in day shifts. The instrument used for data collection was the "Standard Shift Work Index," validated in Italian. Data were statistically analyzed. The response rate was 86%. The nurses engaged in rotating night shifts were statistically significantly younger, more frequently single, and had Bachelors and Masters degrees in nursing. They reported the lowest mean score in the items of job satisfaction, quality and quantity of sleep, with more frequent chronic fatigue, psychological, and cardiovascular symptoms in comparison with the day shift workers, in a statistically significant way. Our results suggest that nurses with rotating night schedule need special attention due to the higher risk for both job dissatisfaction and undesirable health effects.

Shift work and cognitive aging: a longitudinal study.

PubMed

Bokenberger, Kathleen; Ström, Peter; Dahl Aslan, Anna K; Åkerstedt, Torbjörn; Pedersen, Nancy L

2017-09-01

Objectives The few studies of shift work and late life cognitive functioning have yielded mixed findings. The aim of the present study is to estimate the association between shift-work experience and change in cognitive performance before and after retirement age among older adults who were gainfully employed. Methods Five hundred and ninety five participants with no dementia were followed up for a mean of 17.6 standard deviation (SD) 8.8 years from a Swedish population-based sample. Participants had self-reported information on any type of shift-work experience (ever/never) in 1984 and measures of cognitive performance (verbal, spatial, memory, processing speed, and general cognitive ability) from up to 9 waves of cognitive assessments during 1986-2012. Night work history (ever/never) from 1998-2002 was available from a subsample (N=320). Early adult cognitive test scores were available for 77 men. Results In latent growth curve modeling, there were no main effects of "any-type" or night shift work on the mean scores or rate of change in any of the cognitive domains. An interaction effect between any-type shift work and education on cognitive performance at retirement was noted. Lower-educated shift workers performed better on cognitive tests than lower-educated day workers at retirement. Sensitivity analyses, however, indicated that the interactions appeared to be driven by selection effects. Lower-educated day workers demonstrated poorer cognitive ability in early adulthood than lower-educated shift workers, who may have selected jobs entailing higher cognitive demand. Conclusion There was no difference in late-life cognitive aging between individuals with a history of working shifts compared to those who had typical day work schedules during midlife.

The impact of various work schedules on sleep complaints and minor accidents during work or leisure time: evidence from a national survey.

PubMed

Chiu, Hsiao-Yean; Tsai, Pei-Shan

2013-03-01

To explore the prevalence of insomnia symptoms and excessive daytime sleepiness (EDS) in different work schedules and the impact of shift schedules on the risk of minor accidents during work or leisure time. Using the data from Taiwan Social Development Trend Survey in 2005 (n = 18,794), insomnia symptoms, EDS, and minor accidents were analyzed using descriptive statistics and multivariable logistic regression model. The evening-to-night group had significantly higher prevalence rates of insomnia symptoms. Higher prevalence rate of EDS was presented in both day-to-evening and evening-to-night groups. Adjusting for confounders, the day-to-evening shift had a higher odds ratio of minor accidents as compared with the fixed daytime workers. Extended-shift workers tend to experience insomnia symptoms and EDS and have an increased likelihood of minor accidents.

Determinants of vitamin d status among Jordanian employees: Focus on the night shift effect.

PubMed

Alefishat, Eman; Abu Farha, Rana

2016-01-01

To assess the association between night work and 25-hydroxy vitamin D (25OHD) levels, and to evaluate effect of potential risk factors on 25OHD levels. A total of 140 adult Jordanian employees were recruited. Demographic, lifestyle and working patterns data were documented through a well-structured questionnaire. Vitamin D status was assessed by measuring circulating concentrations of 25OHD. Mean 25OHD level was 23.8 ng/ml. No significant difference was found in 25OHD levels between the summer and winter (p = 0.46), or between males and females (p = 0.35). The female night workers had significantly lower serum 25OHD levels compared to the female day workers (p = 0.01). No significant difference in serum 25OHD levels was found between the night and day male workers (p = 0.25). The number of night shifts/month was negatively correlated with 25OHD levels in both the males and females (p = 0.01 and p = 0.007, respectively). Age was positively correlated with 25OHD levels in both the males and females (p = 0.02 and p = 0.001, respectively). Body mass index was negatively associated with 25OHD levels in the whole sample (p = 0.03), but not within each gender group (p = 0.21 for the males and p = 0.09 for the females). Smoking had no significant association with 25OHD levels (p = 0.99 for the males and p = 0.22 for the females). Our results suggest that women working night shifts are at higher risk of 25OHD deficiency, and, consequently, of other health problems linked to 25OHD deficiency. Int J Occup Med Environ Health 2016;29(5):859-870. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Rapid resetting of human peripheral clocks by phototherapy during simulated night shift work.

PubMed

Cuesta, Marc; Boudreau, Philippe; Cermakian, Nicolas; Boivin, Diane B

2017-11-24

A majority of night shift workers have their circadian rhythms misaligned to their atypical schedule. While bright light exposure at night is known to reset the human central circadian clock, the behavior of peripheral clocks under conditions of shift work is more elusive. The aim of the present study was to quantify the resetting effects of bright light exposure on both central (plasma cortisol and melatonin) and peripheral clocks markers (clock gene expression in peripheral blood mononuclear cells, PBMCs) in subjects living at night. Eighteen healthy subjects were enrolled to either a control (dim light) or a bright light group. Blood was sampled at baseline and on the 4 th day of simulated night shift. In response to a night-oriented schedule, the phase of PER1 and BMAL1 rhythms in PBMCs was delayed by ~2.5-3 h (P < 0.05), while no shift was observed for the other clock genes and the central markers. Three cycles of 8-h bright light induced significant phase delays (P < 0.05) of ~7-9 h for central and peripheral markers, except BMAL1 (advanced by +5h29; P < 0.05). Here, we demonstrate in humans a lack of peripheral clock adaptation under a night-oriented schedule and a rapid resetting effect of nocturnal bright light exposure on peripheral clocks.

Shift work and cancer risk: potential mechanistic roles of circadian disruption, light at night, and sleep deprivation.

PubMed

Haus, Erhard L; Smolensky, Michael H

2013-08-01

Shift work that includes a nighttime rotation has become an unavoidable attribute of today's 24-h society. The related disruption of the human circadian time organization leads in the short-term to an array of jet-lag-like symptoms, and in the long-run it may contribute to weight gain/obesity, metabolic syndrome/type II diabetes, and cardiovascular disease. Epidemiologic studies also suggest increased cancer risk, especially for breast cancer, in night and rotating female shift workers. If confirmed in more controlled and detailed studies, the carcinogenic effect of night and shift work will constitute additional serious medical, economic, and social problems for a substantial proportion of the working population. Here, we examine the possible multiple and interconnected cancer-promoting mechanisms as a consequence of shift work, i.e., repeated disruption of the circadian system, pineal hormone melatonin suppression by exposure to light at night, sleep-deprivation-caused impairment of the immune system, plus metabolic changes favoring obesity and generation of proinflammatory reactive oxygen species. Copyright © 2012 Elsevier Ltd. All rights reserved.

Night work and the reproductive health of women: an integrated literature review.

PubMed

Chau, Yu Moon; West, Sandra; Mapedzahama, Virginia

2014-01-01

The aim of this review was to synthesize current evidence on the effects of night work on the major stages of women's reproductive health, specifically the menstrual cycle, fertility, pregnancy, and menopause. Current understanding suggests that night work (work that causes disruption of a worker's circadian [day/night] rhythms) adversely affects workers' health and well-being. A complex relationship exists between circadian rhythms and reproductive hormones, and this may potentially increase the vulnerability of women to the detrimental effect of night work, including during menopause. A systematic search was conducted (March-May 2011) via CINAHL, MEDLINE, Sociological Abstracts, and Business Source Premier for primary research studies written in English using the key words "shift-work" and "female/women." Findings of identified articles were themed to pregnancy, fertility, aspects of menstrual cycles, and menopause. Twenty articles were identified, (13 articles concerning pregnancy, 3 addressing fertility, and 4 addressing aspects of the menstrual cycle) but no studies addressing menopause were located. All identified articles demonstrated problematic approaches to the determination of night-work exposure. Evidence of the impact of night work on female reproductive health as presented in the current literature is inconclusive. Moreover, available evidence needs to be interpreted with caution, given the various limitations and inconsistencies among the studies in the measurement of night-work exposure and shift-work patterns. Studies that focus specifically on night work are needed to facilitate an understanding of the impact of circadian disruption on the reproductive health of women undertaking night work. © 2013 by the American College of Nurse-Midwives.

Association Between Rotating Night Shift Work and Risk of Coronary Heart Disease Among Women.

PubMed

Vetter, Céline; Devore, Elizabeth E; Wegrzyn, Lani R; Massa, Jennifer; Speizer, Frank E; Kawachi, Ichiro; Rosner, Bernard; Stampfer, Meir J; Schernhammer, Eva S

2016-04-26

Prospective studies linking shift work to coronary heart disease (CHD) have been inconsistent and limited by short follow-up. To determine whether rotating night shift work is associated with CHD risk. Prospective cohort study of 189,158 initially healthy women followed up over 24 years in the Nurses' Health Studies (NHS [1988-2012]: N = 73,623 and NHS2 [1989-2013]: N = 115,535). Lifetime history of rotating night shift work (≥3 night shifts per month in addition to day and evening shifts) at baseline (updated every 2 to 4 years in the NHS2). Incident CHD; ie, nonfatal myocardial infarction, CHD death, angiogram-confirmed angina pectoris, coronary artery bypass graft surgery, stents, and angioplasty. During follow-up, 7303 incident CHD cases occurred in the NHS (mean age at baseline, 54.5 years) and 3519 in the NHS2 (mean age, 34.8 years). In multivariable-adjusted Cox proportional hazards models, increasing years of baseline rotating night shift work was associated with significantly higher CHD risk in both cohorts. In the NHS, the association between duration of shift work and CHD was stronger in the first half of follow-up than in the second half (P=.02 for interaction), suggesting waning risk after cessation of shift work. Longer time since quitting shift work was associated with decreased CHD risk among ever shift workers in the NHS2 (P<.001 for trend). [table: see text] Among women who worked as registered nurses, longer duration of rotating night shift work was associated with a statistically significant but small absolute increase in CHD risk. Further research is needed to explore whether the association is related to specific work hours and individual characteristics.

Sleep Quality and Vigilance Differ Among Inpatient Nurses Based on the Unit Setting and Shift Worked.

PubMed

Surani, Salim; Hesselbacher, Sean; Guntupalli, Bharat; Surani, Sara; Subramanian, Shyam

2015-12-01

Sleepiness in nurses has been shown to impact patient care and safety. The objectives of this study are to measure sleep quality, sleepiness, fatigue, and vigilance in inpatient nurses and to assess how setting (intensive care unit versus the general floor) and shift worked (day versus night) affect these measures. Nurses from both the ICU and floor were included in the study. Participants completed questionnaires assessing self-reported sleep quality (Pittsburgh Sleep Quality Index, PSQI), sleepiness (Stanford Sleepiness Scale and Epworth Sleepiness Scale, ESS), and fatigue (Fatigue Severity Scale, FSS). Vigilance was measured by means of the psychomotor vigilance test (PVT), before and after a 12-hour duty shift. The ESS was abnormal in 22% of all nurses, the FSS was abnormal in 33%, and the global PSQI was abnormal in 63%. More ICU nurses than floor nurses reported abnormal sleep quality (component 5) on the PSQI. Sleep medication use (PSQI component 6) was higher in night shift nurses. The FSS was greater in night shift nurses. On preshift PVT testing, day-shift nurses overall provided faster mean reaction time (RT) than night-shift nurses. ICU nurses working the day shift made more than twice as many total errors and false starts than day shift floor nurses. Floor nurses demonstrated a significant decrease from preshift to postshift in the mean of the fastest 10% RT. Our data indicate that a significant number of inpatient nurses have impaired sleep quality, excessive sleepiness, and abnormal fatigue, which may place them at a greater risk of making medical errors and harming patients; these problems are especially pronounced in night shift workers. PVT results were inconsistent, but floor and day shift nurses performed better on some tasks than ICU and night shift nurses.

Sitting Time, Physical Activity and Sleep by Work Type and Pattern—The Australian Longitudinal Study on Women’s Health

PubMed Central

Clark, Bronwyn K.; Kolbe-Alexander, Tracy L.; Duncan, Mitch J.; Brown, Wendy

2017-01-01

Data from the Australian Longitudinal Study on Women’s Health were used to examine how work was associated with time spent sleeping, sitting and in physical activity (PA), in working women. Young (31–36 years; 2009) and mid-aged (59–64 years; 2010) women reported sleep (categorised as shorter ≤6 h/day and longer ≥8 h/day) and sitting time (work, transport, television, non-work computer, and other; summed for total sitting time) on the most recent work and non-work day; and moderate and vigorous PA (categorised as meeting/not meeting guidelines) in the previous week. Participants reported occupation (manager/professional; clerical/sales; trades/transport/labourer), work hours (part-time; full-time) and work pattern (shift/night; not shift/night). The odds of shorter sleep on work days was higher in both cohorts for women who worked shift or night hours. Longer sitting time on work days, made up primarily of sitting for work, was found for managers/professionals, clerical/sales and full-time workers. In the young cohort, clerical/sales workers and in the mid-aged cohort, full-time workers were less likely to meet PA guidelines. These results suggest multiple behaviour interventions tailored to work patterns and occupational category may be useful to improve the sleep, sitting and activity of working women. PMID:28287446

Sitting Time, Physical Activity and Sleep by Work Type and Pattern-The Australian Longitudinal Study on Women's Health.

PubMed

Clark, Bronwyn K; Kolbe-Alexander, Tracy L; Duncan, Mitch J; Brown, Wendy

2017-03-10

Data from the Australian Longitudinal Study on Women's Health were used to examine how work was associated with time spent sleeping, sitting and in physical activity (PA), in working women. Young (31-36 years; 2009) and mid-aged (59-64 years; 2010) women reported sleep (categorised as shorter ≤6 h/day and longer ≥8 h/day) and sitting time (work, transport, television, non-work computer, and other; summed for total sitting time) on the most recent work and non-work day; and moderate and vigorous PA (categorised as meeting/not meeting guidelines) in the previous week. Participants reported occupation (manager/professional; clerical/sales; trades/transport/labourer), work hours (part-time; full-time) and work pattern (shift/night; not shift/night). The odds of shorter sleep on work days was higher in both cohorts for women who worked shift or night hours. Longer sitting time on work days, made up primarily of sitting for work, was found for managers/professionals, clerical/sales and full-time workers. In the young cohort, clerical/sales workers and in the mid-aged cohort, full-time workers were less likely to meet PA guidelines. These results suggest multiple behaviour interventions tailored to work patterns and occupational category may be useful to improve the sleep, sitting and activity of working women.

The association between shift work and sick leave: a systematic review

PubMed Central

van Drongelen, Alwin; Holte, Kari Anne; Labriola, Merete; Lund, Thomas; van Mechelen, Willem; van der Beek, Allard J

2012-01-01

Shift work is associated with a number of negative health outcomes, although it is not known whether it is associated with sick leave. This systematic review therefore aimed to determine whether an association exists between shift work and sick leave. A systematic literature search was conducted in six databases on observational studies. Two reviewers independently selected relevant articles and appraised methodological quality. Data extraction was performed independently by review couples. Articles were categorised according to shift work characteristics and summarised using a levels of evidence synthesis. In total, the search strategy yielded 1207 references, of which 24 studies met the inclusion criteria. Nine studies were appraised as high quality and used in the levels of evidence synthesis. Two high quality longitudinal studies found a positive association between fixed evening shifts and longer sick leave for female healthcare workers. The evidence was assessed as strong. Evidence was inconclusive for rotating shifts, shift work including nights, for fixed night work, and for 8-hour and 12-hour shifts. The association found between evening work and sick leave in female healthcare workers implies that the association between shift work and sick leave might be schedule and population specific. To study the association further, more high quality studies are necessary that assess and adjust for detailed shift work exposure. PMID:22767871

Rotating Night-Shift Work and Lung Cancer Risk Among Female Nurses in the United States

PubMed Central

Schernhammer, Eva S.; Feskanich, Diane; Liang, Geyu; Han, Jiali

2013-01-01

The risk of lung cancer among night-shift workers is unknown. Over 20 years of follow-up (1988–2008), we documented 1,455 incident lung cancers among 78,612 women in the Nurses' Health Study. To examine the relationship between rotating night-shift work and lung cancer risk, we used multivariate Cox proportional hazard models adjusted for detailed smoking characteristics and other risk factors. We observed a 28% increased risk of lung cancer among women with 15 or more years spent working rotating night shifts (multivariate relative risk (RR) = 1.28, 95% confidence interval (CI): 1.07, 1.53; Ptrend = 0.03) compared with women who did not work any night shifts. This association was strongest for small-cell lung carcinomas (multivariate RR = 1.56, 95% CI: 0.99, 2.47; Ptrend = 0.03) and was not observed for adenocarcinomas of the lung (multivariate RR = 0.91, 95% CI: 0.67, 1.24; Ptrend = 0.40). Further, the increased risk associated with 15 or more years of rotating night-shift work was limited to current smokers (RR = 1.61, 95% CI: 1.21, 2.13; Ptrend < 0.001), with no association seen in nonsmokers (Pinteraction = 0.03). These results suggest that there are modestly increased risks of lung cancer associated with extended periods of night-shift work among smokers but not among nonsmokers. Though it is possible that this observation was residually confounded by smoking, our findings could also provide evidence of circadian disruption as a “second hit” in the etiology of smoking-related lung tumors. PMID:24049158

Contributors to shift work tolerance in South Korean nurses working rotating shift.

PubMed

Jung, Hye-Sun; Lee, Bokim

2015-05-01

Shift workers have rapidly increased in South Korea; however, there is no published research exploring shift work tolerance among South Korean workers. This study aimed to investigate factors related to shift work tolerance in South Korean nurses. The sample comprised of 660 nurses who worked shifts in a large hospital in South Korea. A structured questionnaire included following comprehensive variables: demographic (age and number of children), individual (morningness and self-esteem), psychosocial (social support and job stress), lifestyle (alcohol consumption, physical activity, and BMI), and working condition factors (number of night shifts and working hours). Shift work tolerance was measured in terms of insomnia, fatigue, and depression. The results of hierarchical regressions indicate that all variables, except for three, number of children, BMI, and working hours, were related to at least one of the symptoms associated with shift work tolerance. Based on these results, we offer some practical implications to help improve shift work tolerance of workers. Copyright © 2014 Elsevier Inc. All rights reserved.

The role of human-at-work systems in business sustainability: perspectives based on expert and qualified production workers in a manufacturing enterprise.

PubMed

Genaidy, Ash M; Rinder, Maria M; Sequeira, Reynold; A-Rehim, Amal

2010-04-01

A community of highly qualified employees is desirable for the workforce to become a competitive business advantage, improving and sustaining corporate health. Currently, the scientific literature is limited on information comparing the assessment of expert and qualified workers for the employee-work environment interface. Such information would be valuable for industrial managers to obtain and act on the different perspectives of its workers for business improvement and survivability. A primary objective of this study is to explore the perspectives of expert and qualified workers on the quality of the employee-work environment interface in a manufacturing enterprise. This investigation was performed in a production department in a small manufacturing enterprise. Two expert workers participated in the study, with each being in the company for 30 years and having performed all jobs in the production department as well as supervisory and line management responsibilities. A total of 13 qualified workers from day and night shifts were used in the study, with the great majority of workers possessing 10 or more years of on-the-job experience but not acquiring the same specialised knowledge required for operating the technological resources in the department. The work compatibility methodology was used to assess the quality of employee-work environment interface for both expert and qualified workers. Both expert and qualified workers provided similar trends in terms of their compatibility assessment of experienced and acting work domains. In general, the compatibility levels for the day shift were poorer than those obtained for the night shift for acting work domains. The similarities in assessment between the expert and qualified workers were much closer for factors impacting job performance at the task and immediate surrounding levels (i.e. physical and mental task content, physical environment). There were greater differences at the macro level, that is, at the process and enterprise levels, in terms of organisational/social/technological environment. This is particularly noted for the organisational environment. The compatibility values obtained for the experienced domains mirror those obtained for acting domains. The overall workload was assessed as requiring major redesign during the day shift and needing added responsibilities for the night shift according to both expert and qualified workers. The assessment of qualified workers is comparable with that of expert workers for the job content and immediate surroundings. Differences are more observed for process- and enterprise-based factors; thereby, providing company management different perspectives in order to devise organisational strategies conducive for optimum human and corporate health and pointing to the probable interactions of the different systems impacting individual and enterprise performance. STATEMENT OF RELEVANCE: This research examines similarities and differences between qualified and expert workers in their assessment of the worker-work environment interface. The contribution to improved understanding of the complex interactions of human-at-work and enterprise systems should be beneficial to organisations in their quest to remain competitive in a global economy.

Estimating occupational exposure to carcinogens in Quebec.

PubMed

Labrèche, France; Duguay, Patrice; Ostiguy, Claude; Boucher, Alexandre; Roberge, Brigitte; Peters, Cheryl E; Demers, Paul A

2013-09-01

We estimated the extent of exposure to occupational carcinogens in Quebec, Canada, to help raise awareness of occupational cancers. Proportions of workers exposed to 21 recognized and 17 probable carcinogens (according to Quebec occupational health regulation and the International Agency for Research on Cancer [IARC] classification) were extracted from various sources: workplace monitoring data, research projects, a population survey, radiation protection data, exposure estimates from the Carcinogen Exposure Canada (CAREX Canada) Project database, and published exposure data. These proportions were applied to Quebec labor force data. Among the 38 studied, carcinogens with the largest proportions of exposed workers were solar radiation (6.6% of workers), night shift work/rotating shift work including nights (6.0%), diesel exhaust fumes (4.4%), wood dust (2.9%) and polycyclic aromatic hydrocarbons (2.0%). More than 15 carcinogens were identified in several industrial sectors, and up to 100,000 young workers are employed in these sectors. Although crude, estimates obtained with different data sources allow identification of research and intervention priorities for cancer in Quebec. Copyright © 2013 Wiley Periodicals, Inc.

Risk for work-related fatigue among the employees on semiconductor manufacturing lines.

PubMed

Lin, Yu-Cheng; Chen, Yen-Cheng; Hsieh, Hui-I; Chen, Pau-Chung

2015-03-01

To examine the potential risk factors for work-related fatigue (WRF) among workers in modern industries, the authors analyzed the records of need-for-recovery questionnaires and health checkup results for 1545 employees. Compared with regular daytime workers, and after adjusting for confounders, the workers adapting to day-and-night rotating shift work (RSW) had a 4.0-fold (95% confidence interval [CI] = 2.7-5.9) increased risk for WRF, higher than the 2.2-fold risk (95% CI = 1.5-3.3) for persistent shift workers. Based on highest education level, the male employees with university degrees had the highest adjusted odds ratio (a-OR) 2.8 (95% CI = 1.0-7.8) for complaining of WRF versus compulsory education group. For female workers, currently married/cohabiting status was inversely associated with WRF (a-OR = 0.5; 95% CI = 0.2-0.9), and child-rearing responsibility moderately increased WRF risk (a-OR = 1.9; 95% CI = 1.0-3.7). Day-and-night RSW and the adaptation, educational levels of males, and domestic factors for females contributed to WRF among semiconductor manufacturing employees. © 2013 APJPH.

Analysis of the workload imposed on the workers of the imprint and cutting/welding sectors of a flexible packaging manufacturer.

PubMed

de M Guimarães, L B; Pessa, S L R; Biguelini, C

2012-01-01

This article presents a study on the evaluation of the workload imposed to workers of two sectors of a flexible packaging manufacturer that operates in three shifts. The workers are allocated in one of the shifts (morning, evening and night shifts) without evaluation of their chronotype and/or social needs. The Imprint sector has a more dynamic work, which is done only by man due to the effort demanded by handling loads. The work in the Cutting/Welding sector is static, done mainly by women. The results showed that the overall workload was the same in the Imprint and Cutting/Welding sectors, because physical effort for load handling is higher in the former but the latter involves high static load. The levels of urinary catecholamines and salivary cortisol were consistent with the workers biological clock showing that none of the workers changed his/her biological cycle to accommodate to the time of the shift schedule.

[Shift work and night work: what effect on blood pressure?].

PubMed

Cassat, M; Wuerzner, G; Burnier, M

2015-09-09

Shift work has become more and more common for the last thirty years. By definition, shift work disturbs the circadian rhythm and the internal clock. Even if the pathophysiological mechanisms are not well understood, a greater cardiovascular risk has been attributed to shift work. Cross-sectional and cohort studies have identified an association between shift work and an elevated blood pressure. Shift workers also present a higher incidence of hypertension and progression than day workers. Unfortunately, the heterogeneity of the studies, the multiple confounding factors, as well as the complexity to achieve a suitable comparison group make it impossible to draw firm clinical evidence. Nevertheless, this population needs a medical follow-up focused on the cardiovascular risks and blood pressure.

[Sleep disorders among physicians on shift work].

PubMed

Schlafer, O; Wenzel, V; Högl, B

2014-11-01

Sleep disorders in physicians who perform shift work can result in increased risks of health problems that negatively impact performance and patient safety. Even those who cope well with shift work are likely to suffer from sleep disorders. The aim of this manuscript is to discuss possible causes, contributing factors and consequences of sleep disorders in physicians and to identify measures that can improve adaptation to shift work and treatment strategies for shift work-associated sleep disorders. The risk factors that influence the development of sleep disorders in physicians are numerous and include genetic factors (15 % of the population), age (> 50 years), undiagnosed sleep apnea,, alcohol abuse as well as multiple stress factors inherent in clinical duties (including shift work), research, teaching and family obligations. Several studies have reported an increased risk for medical errors in sleep-deprived physicians. Shift workers have an increased risk for psychiatric and cardiovascular diseases and shift work may also be a contributing factor to cancer. A relationship has been reported not only with sleep deprivation and changes in food intake but also with diabetes mellitus, obesity, hypertension and coronary heart disease. Nicotine and alcohol consumption are more frequent among shift workers. Increased sickness and accident rates among physicians when commuting (especially after night shifts) have a socioeconomic impact. In order to reduce fatigue and to improve performance, short naps during shiftwork or naps plus caffeine, have been proposed as coping strategies; however, napping during adverse circadian phases is less effective, if not impossible when unable to fall asleep. Bright and blue light supports alertness during a night shift. After shiftwork, direct sunlight exposure to the retina can be avoided by using dark sunglasses or glasses with orange lenses for commuting home. The home environment for daytime sleeping after a night shift should be very dark to allow endogenous melatonin secretion, which is a night signal and supports continuous sleep. Sleep disorders can be treated with timed light exposure, as well as behavioral and environmental strategies to compensate for sleep deprivation. Fatigue due to sleep deprivation can only be systematically treated with sleep.

Do Working Hours and Type of Work Affect Obesity in South Korean Female Workers? Analysis of the Korean Community Health Survey.

PubMed

Yoon, Chang-Gyo; Kang, Mo-Yeol; Bae, Kyu-Jung; Yoon, Jin-Ha

2016-02-01

The prevalence of obesity and the female labor participation rate have been rapidly increasing in South Korea. To examine the relationship between these factors, we investigated the association between timing and type of work and obesity in the Korean female working population. Data collected by the 2008 Community Health Survey (CHS) were analyzed using a complex, stratified, multistage, probability cluster sampling method. Descriptive analysis of relevant variables was performed using the chi-square test, and work-related variables by work type were identified using multivariate logistic regression. The relationship between long working hours, night/shift work, and body-mass index in female workers and explanatory, stratifying, and dependent variables and covariates was analyzed using multiple logistic regression models. A total of 42,234 CHS participants were eligible for study inclusion. Among both manual and nonmanual workers, working less than 40 (adjusted odds ratio [aOR] 1.18, 95% confidence interval [CI] 1.07-1.31 and aOR 1.29; 95% CI 1.09-0.52, respectively) or more than 60 (aOR 1.18, 95% CI 1.06-1.30 and aOR 1.28, 95% CI 1.04-1.57, respectively) hours per week was significantly associated with obesity after controlling for covariates. However, working type (day or night/shift) was significantly associated with obesity only in nonmanual workers (aOR 1.20, 95% CI 1.01-1.42). When we controlled working type in the model, manual workers who work more than 60 hours show higher likelihood of being obese (OR 1.10, 95% CI 1.02-1.18). Working fewer (<40) or more than (>60) hours per week is significantly associated with obesity in the Korean female working population, regardless of the type of work. The type of work (day vs. night/shift work) was significantly associated with obesity only in only nonmanual workers.

Sleep duration and sleep-related problems in different occupations in the Hordaland Health Study.

PubMed

Ursin, Reidun; Baste, Valborg; Moen, Bente E

2009-05-01

The aim of this study was to examine the relationship between occupation and sleep duration, sleepiness, insufficient sleep, and insomnia in day and shift workers (including night work and watches). The study was population-based and cross-sectional, and relied on self-administered questionnaires. It was conducted as part of the 1997-1999 Hordaland Health Study in collaboration with the Norwegian National Health Screening Service. Aged 40-45 years, 7782 participants answered a sleep questionnaire, reporting their occupation and whether or not they were employed in shift work. Our study found differences in sleep duration during the working week between occupational groups; in both shift and day workers. Craft workers, plant operators, and drivers slept less than leaders, and non-personal and personal service workers. Within some occupations (leaders, personal service workers, and plant operators), shift workers slept less than day workers. The mean sleep duration of shift workers was 15 minutes shorter than that of day workers. Rise times, but not bedtimes, were earlier in craft-and construction workers, plant operators, and drivers than in leaders and non-personal and personal service workers, particularly day workers. When adjusted for shift work and working hours - compared to leaders - craft workers, plant operators, and drivers had an increased risk of daytime sleepiness (odds ratio 1.5, 1.8, and 1.8 respectively) and of falling asleep at work (odds ratio 1.6, 2.1 and 2.0 respectively). Shift workers had an increased risk of falling asleep at work and insomnia. Occupation has separate effects on sleep duration and sleep-related problems, independent of the effects of shift work.

Do working environment interventions reach shift workers?

PubMed

Nabe-Nielsen, Kirsten; Jørgensen, Marie Birk; Garde, Anne Helene; Clausen, Thomas

2016-01-01

Shift workers are exposed to more physical and psychosocial stressors in the working environment as compared to day workers. Despite the need for targeted prevention, it is likely that workplace interventions less frequently reach shift workers. The aim was therefore to investigate whether the reach of workplace interventions varied between shift workers and day workers and whether such differences could be explained by the quality of leadership exhibited at different times of the day. We used questionnaire data from 5361 female care workers in the Danish eldercare sector. The questions concerned usual working hours, quality of leadership, and self-reported implementation of workplace activities aimed at stress reduction, reorganization of the working hours, and participation in improvements of working procedures or qualifications. Compared with day workers, shift workers were less likely to be reached by workplace interventions. For example, night workers less frequently reported that they had got more flexibility (OR 0.5; 95 % CI 0.3-0.7) or that they had participated in improvements of the working procedures (OR 0.6; 95 % CI 0.5-0.8). Quality of leadership to some extent explained the lack of reach of interventions especially among fixed evening workers. In the light of the evidence of shift workers' stressful working conditions, we suggest that future studies focus on the generalizability of results of the present study and on how to reach this group and meet their needs when designing and implementing workplace interventions.

Night shift work, chronotype and prostate cancer risk in the MCC-Spain case-control study.

PubMed

Papantoniou, Kyriaki; Castaño-Vinyals, Gemma; Espinosa, Ana; Aragonés, Nuria; Pérez-Gómez, Beatriz; Burgos, Javier; Gómez-Acebo, Inés; Llorca, Javier; Peiró, Rosana; Jimenez-Moleón, Jose Juan; Arredondo, Francisco; Tardón, Adonina; Pollan, Marina; Kogevinas, Manolis

2015-09-01

Night shift work has been classified as a probable human carcinogen based on experimental studies and limited human evidence on breast cancer. Evidence on other common cancers, such as prostate cancer, is scarce. Chronotype is an individual characteristic that may relate to night work adaptation. We evaluated night shift work with relation to prostate cancer, taking into account chronotype and disease severity in a population based case-control study in Spain. We included 1,095 prostate cancer cases and 1,388 randomly selected population controls. We collected detailed information on shift schedules (permanent vs. rotating, time schedules, duration, frequency), using lifetime occupational history. Sociodemographic and lifestyle factors were assessed by face-to-face interviews and chronotype through a validated questionnaire. We used unconditional logistic regression analysis adjusting for potential confounders. Subjects who had worked at least for one year in night shift work had a slightly higher prostate cancer risk [Odds Ratio (OR) 1.14; 95%CI 0.94, 1.37] compared with never night workers; this risk increased with longer duration of exposure (≥ 28 years: OR 1.37; 95%CI 1.05, 1.81; p-trend = 0.047). Risks were more pronounced for high risk tumors [D'Amico classification, Relative Risk Ratio (RRR) 1.40; 95%CI 1.05, 1.86], particularly among subjects with longer duration of exposure (≥28 years: RRR 1.63; 95%CI 1.08, 2.45; p-trend = 0.027). Overall risk was higher among subjects with an evening chronotype, but also increased in morning chronotypes after long-term night work. In this large population based study, we found an association between night shift work and prostate cancer particularly for tumors with worse prognosis. © 2014 UICC.

Sleep loss and circadian disruption in shift work: health burden and management.

PubMed

Rajaratnam, Shantha M W; Howard, Mark E; Grunstein, Ronald R

2013-10-21

About 1.5 million Australians are shift workers. Shift work is associated with adverse health, safety and performance outcomes. Circadian rhythm misalignment, inadequate and poor-quality sleep, and sleep disorders such as sleep apnoea, insomnia and shift work disorder (excessive sleepiness and/or insomnia temporally associated with the work schedule) contribute to these associations. Falling asleep at work at least once a week occurs in 32%-36% of shift workers. Risk of occupational accidents is at least 60% higher for non-day shift workers. Shift workers also have higher rates of cardiometabolic diseases and mood disturbances. Road and workplace accidents related to excessive sleepiness, to which shift work is a significant contributor, are estimated to cost $71-$93 billion per annum in the United States. There is growing evidence that understanding the interindividual variability in sleep-wake responses to shift work will help detect and manage workers vulnerable to the health consequences of shift work. A range of approaches can be used to enhance alertness in shift workers, including screening and treating sleep disorders, melatonin treatment to promote sleep during the daytime, and avoidance of inappropriate use of sedatives and wakefulness-promoters such as modafinil and caffeine. Short naps, which minimise sleep inertia, are generally effective. Shifting the circadian pacemaker with appropriately timed melatonin and/or bright light may be used to facilitate adjustment to a shift work schedule in some situations, such as a long sequence of night work. It is important to manage the health risk of shift workers by minimising vascular risk factors through dietary and other lifestyle approaches.

Association between depressive symptoms and morningness-eveningness, sleep duration and rotating shift work in Japanese nurses.

PubMed

Togo, Fumiharu; Yoshizaki, Takahiro; Komatsu, Taiki

2017-01-01

Higher depressive symptoms have been reported in rotating shift workers compared with day workers. Depressive symptoms in adults who do not engage in night work have also been shown to be associated with chronotype and sleep duration. This study examines associations between depressive symptoms, morningness-eveningness (i.e. the degree to which people prefer to be active in the morning or the evening), sleep duration and rotating shift work. Japanese nurses (1252 day workers and 1780 rotating shift workers, aged 20-59) were studied using a self-administered questionnaire. The questionnaire covered depressive symptoms, morningness-eveningness, sleep habits and demographic characteristics of the participants. The Center for Epidemiologic Studies Depression Scale (CES-D) was used to determine the levels of depressive symptoms. A Japanese version of the Morningness-Eveningness Questionnaire (MEQ) was used to measure morningness-eveningness. The CES-D score of shift workers was significantly (p < 0.05) higher than that of day workers. The MEQ score was significantly (p < 0.05) lower (i.e. greater eveningness) in shift workers than in day workers. Sleep duration on the day shift was significantly (p < 0.05) shorter in shift workers than in day workers. Simple linear regression revealed that the MEQ score, sleep duration on the day shift and current work shift (i.e. rotating shift work) were significantly (p < 0.05) associated with the CES-D score. Multivariate linear regression indicated that greater eveningness and shorter sleep duration were independently associated with higher CES-D scores, while rotating shift work was not. These associations between the MEQ score, the sleep duration and the CES-D score were also confirmed in both day workers and shift workers when the groups were analyzed separately. These results suggest that greater eveningness and shorter sleep duration on the day shift were independently associated with higher levels of depressive symptoms, which may explain associations between rotating shift workers and depressive symptoms. These findings have important implications for the development of novel strategies for preventing poor mental health in day workers and rotating shift workers.

[Associations among physical condition, life hour, and dietary intake male Japanese shift workers: physical condition and lifestyle survey of male Japanese shift workers].

PubMed

Fukumura, Tomoe; Yoshita, Katsushi; Tabata, Masaji

2015-01-01

The purpose of this study was to understand the actual state of life hours (working time, sleep time, and time of meal intake) and dietary habits of male shift work employees, and to elucidate the impact of working arrangements and dietary habits on their physical condition and health problems. The subjects were 187 male employees (aged 18-64 years) working for an industrial company in Toyama prefecture. We used a self-administered questionnaire to assess dietary habit, lifestyle habits, and life hours at the time of a periodic health examination in April 2013. The subjects were grouped based on their working condition (i.e., day shift, late shift, and late-night shift) into two groups of day shift (n = 107) and shiftwork (n = 80). The proportion of time spent sleeping and feeding was determined in half hour increments, and the incidences of skipping meals (breakfast, lunch and dinner) and midnight snack intake were calculated for each working condition. We also examined the association between the frequency of eating and physical condition for each working condition. The state of life hours of the shiftwork group during the day was similar to that of the day shift group. However, the workers' state of life hours, incidences of skipping meals, and midnight snack intake varied considerably when working at the other shift times. In the shiftwork group, regardless of the working patterns, the BMI and % body fat of the group that ate more than three times a day were significantly lower than those of the group that ate less than twice a day. The results of the present study suggest that it is difficult to ensure the time and opportunity for meals for shift workers. We consider that it is necessary to prevent them skipping of meals, and to support a proper dietary intake during the night.

Shift work and health--a critical review of the literature on working hours.

PubMed

Harrington, J M

1994-09-01

Working outside normal hours either by extended days or shift work is a fact of industrial society. Its economic advantages must be weighed against detrimental effects on the individual worker in the form of circadian rhythm disturbance, poorer quality and quantity of sleep and increased fatigue. The link between shift work and increased cardiovascular morbidity and mortality has strengthened in recent years. The case for an association with gastrointestinal disease remains quite good. Evidence of poorer work performance and increased accidents, particularly on the night shift, is persuasive, although individual factors may be as important as workplace factors. Correct shift work scheduling is important and for rotating shifts, rapid forward rotation is the least disruptive option. The compressed working week of 10 to 12-hour shifts is gaining popularity but evidence is too scant at present to suggest there are many long-term health and safety risks provided the rest day block is preserved. Optimal hours for the working week cannot be formulated on present scientific evidence, though working more than 48-56 hours a week probably carries serious health and safety implications. The inherent conflict between the interest of the worker and the enterprise over unsocial hours can be mitigated by improvements in working conditions especially at night and by advice to the worker on coping strategies. Further research is needed on the effects of the compressed working week, as well as the influence of culture, task and gender on any health effects. Studies to define individual characteristics which may cause shift work intolerance would be of great practical use.

The Impact of a Rigorous Multiple Work Shift Schedule and Day Versus Night Shift Work on Reaction Time and Balance Performance in Female Nurses: A Repeated Measures Study.

PubMed

Thompson, Brennan J; Stock, Matt S; Banuelas, Victoria K; Akalonu, Chibuzo C

2016-07-01

The aim of this study was to determine the impact of a demanding work schedule involving long, cumulative work shifts on response time and balance-related performance outcomes and to evaluate the prevalence of musculoskeletal disorders between day and night shift working nurses. A questionnaire was used to identify the prevalence of past (12-month) and current (7-day) musculoskeletal disorders. Nurses worked three 12-hour work shifts in a 4-day period. Reaction time and balance tests were conducted before and after the work period. The work period induced impairments for reaction time, errors on reaction time tasks, and balance performance, independent of shift type. Musculoskeletal symptom prevalence was high in workers of both work shifts. Compressed work shifts caused performance-based fatigue in nurses. Reaction time and balance tests may be sensitive fatigue identification markers in nurses.

Acute effects of different light spectra on simulated night-shift work without circadian alignment.

PubMed

Canazei, Markus; Pohl, Wilfried; Bliem, Harald R; Weiss, Elisabeth M

2017-01-01

Short-wavelength and short-wavelength-enhanced light have a strong impact on night-time working performance, subjective feelings of alertness and circadian physiology. In the present study, we investigated acute effects of white light sources with varied reduced portions of short wavelengths on cognitive and visual performance, mood and cardiac output.Thirty-one healthy subjects were investigated in a balanced cross-over design under three light spectra in a simulated night-shift paradigm without circadian adaptation.Exposure to the light spectrum with the largest attenuation of short wavelengths reduced heart rate and increased vagal cardiac parameters during the night compared to the other two light spectra without deleterious effects on sustained attention, working memory and subjective alertness. In addition, colour discrimination capability was significantly decreased under this light source.To our knowledge, the present study for the first time demonstrates that polychromatic white light with reduced short wavelengths, fulfilling current lighting standards for indoor illumination, may have a positive impact on cardiac physiology of night-shift workers without detrimental consequences for cognitive performance and alertness.

Comparison of menstrual disorders in hospital nursing staff according to shift work pattern.

PubMed

Albert-Sabater, Josep Amílcar; Martínez, José Miguel; Baste, Valborg; Moen, Bente E; Ronda-Perez, Elena

2016-11-01

To assess the association between work in a rotating shift schedule and menstruation characteristics among nurse staff in a prospective study. Rotating shifts have been linked to alterations in the reproductive cycle. In the case of menstrual alterations, the conclusions are not clear. Prospective epidemiological study with follow-up over four months. All the female nurse staff (<40 years) in a hospital were interviewed, collecting sociodemographic and employment information. They were given a menstrual diary to keep a record of their shifts and characteristics of their menstruation (duration, amount of blood, dysmenorrhoea). They had two types of shifts: (1) Rotating shift schedule (two mornings, two afternoons, one night and two days off) including morning shifts (8:00-15:00), afternoon/evening shifts (15:00-22:00) and night shifts (22:00-8:00), and (2) Day shift schedule including morning shifts (8:00-15:00) and/or afternoon/evening shifts (15:00-22:00). The crude and adjusted odds ratios with 95% confidence interval were calculated using logistic generalised estimating equations (GEE) taking into account the correlations of multiple cycles per worker. One hundred and thirteen workers on the rotating shift and 75 on the day shift participated, and information from 730 menstrual cycles were obtained. There were no differences in prolonged duration, dysmenorrhoea, prolonged duration dysmenorrhoea and excessive bleeding among nurses on rotating shift compared to those on the day shift. For prolonged duration of menstruation, workers with more than five years on the rotating shift showed a slightly lower (nonsignificant) risk compared with those with <5 years. Nurse staff on the rotating shift did not show increased risk of having menstrual disorders comparing with day staff. Shifts with short rotation cycles and a progressive sequence do not appear to cause menstrual disorders in nurse staff who work rotating shifts. © 2016 John Wiley & Sons Ltd.

The impact of sleep deprivation on surgeons' performance during night shifts.

PubMed

Amirian, Ilda

2014-09-01

The median incidence of adverse events that may result in patient injury is a total of 9% of all in-hospital admissions. In order to reduce this high incidence initiatives are continuously worked on that can reduce the risk of patient harm during admission by strengthening hospital systems. However, the influence of physicians' shift work on the risk on adverse events in patients remains controversial. In the studies included in this PhD thesis we wished to examine the impact of sleep deprivation and circadian rhythm disturbances on surgeons' during night shifts. Further we wished to examine the impact sleep deprivation had on surgeons' performance as a measure of how patient safety would be affected. We found that sleep deprivation subjectively had an impact on the surgeons and that they were aware of the effect fatigue had on their work performance. As a result they applied different mechanisms to cope with fatigue. Attending surgeons felt that they had a better overview now, due to more experience and better skills, than when they were residents, despite the fatigue on night shifts. We monitored surgeons' performance during night shifts by laparoscopic simulation and cognitive tests in order to assess their performance; no deterioration was found when pre call values were compared to on call values. The surgeons were monitored prospectively for 4 days across a night shift in order to assess the circadian rhythm and sleep. We found that surgeons' circadian rhythm was affected by working night shifts and their sleep pattern altered, resembling that of shift workers on the post call day. We assessed the quality of admission in medical records as a measure of surgeons' performance, during day, evening and night hours and found no deterioration in the quality of night time medical records. However, consistent high errors were found in several categories. These findings should be followed up in the future with respect of clarifying mechanism and consequences for patient safety. In conclusion the assessment of the impact of sleep deprivation on surgeons' performance during night shift is complex and multi-faceted. Surgeons do feel an impact of sleep deprivation during night shifts, and their circadian rhythm is affected. Despite this, it appears that the surgeons are able to compensate for the effects of sleep loss. We did not find any results to support that sleep loss results in psychomotor or cognitive deterioration during a 17-hour night shift or that sleep deprivation during a night shift results in reduced patient safety.

Night-shift work, sleep duration, daytime napping, and breast cancer risk.

PubMed

Wang, Pan; Ren, Fang-Mei; Lin, Ying; Su, Feng-Xi; Jia, Wei-Hua; Su, Xue-Fen; Tang, Lu-Ying; Ren, Ze-Fang

2015-04-01

Sleep habits vary among different countries, and sleep problems may cause various health problems. The aim of our study was to evaluate the separate and combined associations of night-shift work, sleep duration, and daytime napping with breast cancer risk among the Chinese population. This study conducted face-to-face interviews with 712 women diagnosed with incident invasive breast cancer before treatment and 742 age-matched controls. Information on sleep habits, demographic characteristics, and suspected or established risk factors of breast cancer were collected from the two groups. Multivariate logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). Night-shift work was associated with an increased risk of breast cancer [OR (95% CI): 1.34 (1.05-1.72)]. Compared to women with a sleep duration of 6.1-8.9 h/day, women who had shorter [(≤6.0 h/day) (OR (95% CI): 1.53 (1.10-2.12)] and longer (≥9.0 h/day) sleep duration [(OR (95% CI): 1.59 (1.17-2.17)] had an increased risk of breast cancer. In addition, daytime napping was associated with a reduced risk of breast cancer among night-shift workers [OR (95% CI): 0.57 (0.36-0.90)], but no association was found among women who never had night-shift work [OR (95% CI): 1.01 (0.75-1.35)] (P for interaction = 0.054). Night-shift work and longer sleep duration also synergistically increased breast cancer risk [OR (95% CI): 3.69 (1.94-7.02)] (P for interaction = 0.009). Sleep problems, including night-shift work, and shorter and longer sleep duration, are associated with an increased breast cancer risk. In particular, the combined effects of night-shift work with no daytime napping or longer sleep duration are greater than the independent effects. Copyright © 2014 Elsevier B.V. All rights reserved.

Night shift work and incident diabetes among U.S. black women

PubMed Central

Vimalananda, Varsha G.; Palmer, Julie R.; Gerlovin, Hanna; Wise, Lauren A.; Rosenzweig, James L.; Rosenberg, Lynn; Narváez, Edward A. Ruiz

2015-01-01

Aims To assess shift work in relation to incident type 2 diabetes among African American women. Methods In the Black Women's Health Study (BWHS), an ongoing prospective cohort study, we followed 28,041 participants for incident diabetes during 2005-2013. They answered questions in 2005 about having worked the night shift. We estimated hazard ratios (HR) and 95% confidence intervals (CI) for incident diabetes using Cox proportional hazards models. The basic multivariable model included age, time period, family history of diabetes, education, and neighborhood SES. In further models, we controlled for lifestyle factors and body mass index (BMI). Results Over the 8 years of follow-up, there were 1,786 incident diabetes cases. Relative to never having worked the night shift, HRs (95% CI) of diabetes were 1.17 (1.04, 1.31) for 1-2 years of night shift work, 1.23 (1.06, 1.41) for 3-9 years, and 1.42 (1.19, 1.70) for ≥ 10 years (P-trend < 0.0001). The monotonic positive association between night shift work and type 2 diabetes remained after multivariable adjustment (P-trend = 0.02). The association did not vary by obesity status, but was stronger in women aged < 50 years. Conclusions Long durations of shift work were associated with an increased risk of type 2 diabetes. The association was only partially explained by lifestyle factors and BMI. A better understanding of the mechanisms by which shift work may affect risk of diabetes is needed in view of the high prevalence of shift work among U.S. workers. PMID:25586362

Randomized placebo-controlled field study of the effects of bright light and melatonin in adaptation to night work.

PubMed

Bjorvatn, Bjørn; Stangenes, Kristine; Oyane, Nicolas; Forberg, Knut; Lowden, Arne; Holsten, Fred; Akerstedt, Torbjørn

2007-06-01

This study evaluated the effects of bright light and melatonin on adaptation to night work on an oil rig in the North Sea. Seventeen persons working a schedule of 2 weeks on a 12-hour shift, with the first week on night shift and the second week on day shift (ie, the swing shift schedule) participated. In a randomized controlled crossover design, the shift workers received a placebo, melatonin (3 mg, 1 hour before bedtime), or bright light (30-minute exposure, individually scheduled) during the first 4 days on the night shift and during the first 4 days on the day shift. Subjective and objective measures of sleepiness (Karolinska Sleepiness Scale and a simple serial reaction-time test) and sleep (diary and actigraphy) were recorded. Subjective measures indicated that melatonin modestly reduced sleepiness at work during the day shift and increased sleep by 15-20 minutes per day. Bright light gave values in between those of melatonin and the placebo, but with few significant results. According to the objective measures, bright light improved sleep to a minor degree during the night shift. Hardly any side-effects were reported. Melatonin and bright light modestly improved sleep and sleepiness in this field study. In well-controlled simulated nightwork studies, both melatonin and bright light are more effective in alleviating sleepiness and sleep problems. The less effect in this field study may be due to competing or conflicting factors present in real life or to an inoptimal timing and duration of the treatments.

Night-shift work is associated with increased pain perception.

PubMed

Matre, Dagfinn; Knardahl, Stein; Nilsen, Kristian Bernhard

2017-05-01

Objectives The aim of the present study was to determine whether shift workers exhibit increased perception of experimentally induced pain after working night shifts. Methods The study was a paired cross-over design with two sleep conditions, after at least two nights of habitual sleep and after two consecutive night shifts at work. Fifty-three nurses in rotating shift work participated. The sensitivity to electrically induced pain, heat pain, cold pain, pressure pain and pain inhibition was determined experimentally in each sleep condition. Sleepiness and vigilance were also assessed. Results Night-shift work (NSW) increased the sensitivity to electrically induced pain and heat pain (P≤0.001). Relative to habitual sleep, electrically induced pain increased by 22.3% and heat pain increased by 26.5%. The sensitivity to cold and pressure pain did not change, changes relative to habitual sleep was <5% (P>0.5). Pain inhibition was 66.9% stronger after NSW versus after habitual sleep (P<0.001). Sleepiness (measured with the Karolinska Sleepiness Scale) increased from 4.1 after habitual sleep to 6.9 after NSW (P<0.001). Vigilance decreased after NSW, measured as a 0.03-second decrease in reaction time (P<0.005). Conclusions Changes in pain sensitivity after NSW is measurable with clinically relevant effect sizes and may be an important marker for studies comparing the physiological effects of different shift work schedules. Explanations for the differential effect on different pain modalities should be a focus for future studies.

Armodafinil for treatment of excessive sleepiness associated with shift work disorder: a randomized controlled study.

PubMed

Czeisler, Charles A; Walsh, James K; Wesnes, Keith A; Arora, Sanjay; Roth, Thomas

2009-11-01

To assess the effect of armodafinil, 150 mg, on the physiologic propensity for sleep and cognitive performance during usual night shift hours in patients with excessive sleepiness associated with chronic (> or =3 months) shift work disorder (SWD) of moderate or greater severity. This 12-week, randomized controlled study was conducted at 42 sleep research facilities in North America from April 2 through December 23, 2004, and enrolled 254 permanent or rotating night shift workers with SWD. Entry criteria included excessive sleepiness during usual night shifts for 3 months or longer (corroborated by mean sleep latency of < or =6 minutes on a Multiple Sleep Latency Test), insomnia (sleep efficiency < or =87.5% during daytime sleep), and SWD that was judged clinically to be of moderate or greater severity. Patients received armodafinil, 150 mg, or placebo 30 to 60 minutes before each night shift. Physiologic sleep propensity during night shift hours, clinical impression of severity, patient-reported sleepiness, and cognitive function were assessed during laboratory night shifts at weeks 4, 8, and 12. Armodafinil significantly improved mean (SD) sleep latency from 2.3 (1.6) minutes at baseline to 5.3 (5.0) minutes at final visit, compared with a change from 2.4 (1.6) minutes to 2.8 (2.9) minutes in the placebo group (P<.001). Clinical condition ratings improved in more patients receiving armodafinil (79%) vs placebo (59%) (P=.001). As reported by patients' diaries, armodafinil significantly reduced sleepiness during laboratory nights (P<.001), night shifts at work (P<.001), and the commute home (P=.003). Armodafinil improved performance on standardized memory (P<.001) and attention (power, P=.001; continuity, P<.001) tests compared with placebo. Armodafinil was well tolerated and did not affect daytime sleep, as measured by polysomnography. In patients with excessive sleepiness associated with chronic SWD of moderate or greater severity, armodafinil significantly improved wakefulness during scheduled night work, raising mean nighttime sleep latency above the level considered to indicate severe sleepiness during the daytime. Armodafinil also significantly improved measures of overall clinical condition, long-term memory, and attention. clinicaltrials.gov Identifier: NCT00080288.

VALIDITATION OF A LIGHT QUESTIONNAIRE WITH REAL-LIFE PHOTOPIC ILLUMINANCE MEASUREMENTS: THE HARVARD LIGHT EXPOSURE ASSESSMENT QUESTIONNAIRE

PubMed Central

Bajaj, Archna; Rosner, Bernard; Lockley, Steven; Schernhammer, Eva S.

2011-01-01

Background Light exposure at night is now considered a probable carcinogen. To study the effects of light on chronic diseases like cancer, methods to measure light exposure in large observational studies are needed. We aimed to investigate the validity of self-reported current light exposure. Methods We developed a self-administered semiquantitative light questionnaire, the Harvard Light Exposure Assessment (H-LEA) questionnaire, and compared photopic scores derived from this questionnaire with actual photopic and circadian measures obtained from a real-life 7-day light meter application among 132 women (85 rotating night shift workers and 47 day workers) participating in the Nurses' Health Study II. Results After adjustment for age, BMI, collection day, and night work status, the overall partial Spearman correlation between self-report of light exposure and actual photopic light measurements was 0.72 (P<0.001; Kendall τ =0.57) and 0.73 (P<0.0001; Kendall τ =0.58) when correlating circadian light measurements. There were only minimal differences in accuracy of self-report of light exposure and photopic or circadian light measurement between day (r=0.77 and 0.78, respectively) and rotating night shift workers (r=0.68 and 0.69, respectively). Conclusions The results of this study provide evidence of the criterion validity of self-reported light exposure using the H-LEA questionnaire. Impact: This questionnaire is a practical method of assessing light exposure in large scale epidemiologic studies. PMID:21737411

What work schedule characteristics constitute a problem to the individual? A representative study of Swedish shift workers.

PubMed

Åkerstedt, Torbjörn; Kecklund, Göran

2017-03-01

The purpose was to investigate which detailed characteristics of shift schedules that are seen as problems to those exposed. A representative national sample of non-day workers (N = 2031) in Sweden was asked whether they had each of a number of particular work schedule characteristics and, if yes, to what extent this constituted a "big problem in life". It was also inquired whether the individual's work schedules had negative consequences for fatigue, sleep and social life. The characteristic with the highest percentage reporting a big problem was "short notice (<1 month) of a new work schedule" (30.5%), <11 h off between shifts (27.8%), and split duty (>1.5 h break at mid-shift, 27.2%). Overtime (>10 h/week), night work, morning work, day/night shifts showed lower prevalences of being a "big problem". Women indicated more problems in general. Short notice was mainly related to negative social effects, while <11 h off between shifts was related to disturbed sleep, fatigue and social difficulties. It was concluded that schedules involving unpredictable working hours (short notice), short daily rest between shifts, and split duty shifts constitute big problems. The results challenge current views of what aspects of shift work need improvement, and negative social consequences seem more important than those related to health. Copyright © 2016 Elsevier Ltd. All rights reserved.

Circadian and ultradian rhythms in the feeding behaviour and nutrient intakes of oil refinery operators with shift-work every 3--4 days.

PubMed

Reinberg, A; Migraine, C; Apfelbaum, M; Brigant, L; Ghata, J; Vieux, N; Laporte, A; Nicolai

1979-03-01

Seven healthy adult men, five shift-workers and two non-shift-workers (from 21 to 36 years; mean = 26.4) volunteered to record what and when they ate, both at work and at home, every day, during eight consecutive weeks (Oct. - Dec. 1974). 1) All the subjects maintained the timing of main-meal (lunch and supper) during all shifts. 2) The major intake of protein and lipid was concentrated on the two main meals during all shifts. 3) Only the pattern of carbohydrate intake was modified by the shift-work: e.g. night-shift is associated with nibbling behaviour. 4) However, shift-work and in particular the occurence of nibbling behaviour did not result in change either in the mean 24 h caloric intake, or in the percentage of protein calories. 5) The comparison between the constancy of the timing of major meals and the shift of the timing of circadian rhythm acrophases of the 5 shift-workers leads to conclude that meal timing had a poor synchronizing effect, if any.

Factors associated with shift work disorder in nurses working with rapid-rotation schedules in Japan: the nurses' sleep health project.

PubMed

Asaoka, Shoichi; Aritake, Sayaka; Komada, Yoko; Ozaki, Akiko; Odagiri, Yuko; Inoue, Shigeru; Shimomitsu, Teruichi; Inoue, Yuichi

2013-05-01

Workers who meet the criteria for shift work disorder (SWD) have elevated levels of risk for various health and behavioral problems. However, the impact of having SWD on shiftworkers engaged in rapid-rotation schedules is unknown. Moreover, the risk factors for the occurrence of SWD remain unclear. To clarify these issues, we conducted a questionnaire-based, cross-sectional survey on a sample of shiftworking nurses. Responses were obtained from 1202 nurses working at university hospitals in Tokyo, Japan, including 727 two-shift workers and 315 three-shift workers. The questionnaire included items relevant to age, gender, family structure, work environment, health-related quality of life (QOL), diurnal type, depressive symptoms, and SWD. Participants who reported insomnia and/or excessive sleepiness for at least 1 mo that was subjectively relevant to their shiftwork schedules were categorized as having SWD. The prevalence of SWD in the sampled shiftworking nurses was 24.4%; shiftworking nurses with SWD showed lower health-related QOL and more severe depressive symptoms, with greater rates of both actual accidents/errors and near misses, than those without SWD. The results of logistic regression analyses showed that more time spent working at night, frequent missing of nap opportunities during night work, and having an eveningness-oriented chronotype were significantly associated with SWD. The present study indicated that SWD might be associated with reduced health-related QOL and decreased work performance in shiftworking nurses on rapid-rotation schedules. The results also suggested that missing napping opportunities during night work, long nighttime working hours, and the delay of circadian rhythms are associated with the occurrence of SWD among shiftworking nurses on rapid-rotation schedules.

Permanent night workers´ sleep and psychosocial factors in hospital work. A comparison to day and shift work.

PubMed

Karhula, Kati; Hakola, Tarja; Koskinen, Aki; Ojajärvi, Anneli; Kivimäki, Mika; Härmä, Mikko

2018-05-15

We aimed to study whether permanent night workers sleep and psychosocial factors differ from day workers and shift workers. The participants (n = 9 312, 92% females, average age 45 years, most commonly nurses and departmental secretaries) were day workers (DW, n = 2 672), shift workers (SW, n = 6 486) and permanent night workers (PNW, n = 154). The Finnish Public Sector survey responses from six hospital districts from 2012 were combined to payroll data from 91 days preceding the survey. The data were analyzed using Pearson χ 2 -test, one-way ANOVA and multinomial logistic regression analysis. The PNWs reported slightly longer average sleep length than the SWs or the DWs (7:27 vs. 7:13 and 7:10 h, p < 0.001). The PNWs reported least often difficulties in maintaining sleep (p < 0.001) compared to the SWs and the DWs. The PNWs reported most often difficulties to fall asleep and fatigue during free-time (p-values <0.001). The DWs and PNWs experienced less often work-life conflict than the SWs (25 and 26 vs. 38%, p < 0.001). The PNWs were more often satisfied with autonomy at work and appreciation and fair treatment by colleagues than the DWs or the SWs (p < 0.001). The SWs and PNWs reported remarkably higher occurrence of verbal (p < 0.001, OR 3.71, 95% CI 3.23-4.27 and OR 7.67, 95% CI 5.35-10.99, respectively) and physical workplace violence (p < 0.001, OR 9.24, 95% CI 7.17-11.90 and OR 28.34, 95% CI 16.64-43.06, respectively) compared to DWs. Conclusively, PNWs reported contradictory differences in sleep quality compared to DWs and SWs. PNWs are more often satisfied with their colleagues and autonomy at work than DWs or SWs but face workplace violence remarkably more often.

Evaluation of the effect of shift work on serum cholesterol and triglyceride levels.

PubMed

Akbari, Hamed; Mirzaei, Ramazan; Nasrabadi, Tahereh; Gholami-Fesharaki, Mohammad

2015-01-01

Working outside daylight hours (7 am to 7 pm) is called shift work. Shift work is a common practice in many industries and factories such as steel industries, petroleum industries, power plants, and in some services such as medicine and nursing and police forces, in which professionals provide services during day and night. Considering the contradictory reports of different studies, we decided to evaluate the effect of shift work on cholesterol and triglyceride (TG) levels through a historical cohort on steel industry workers. This retrospective cohort study was performed on all the staff of Isfahan's Mobarakeh Steel Company between years 2002 and 2011. There were 5773 participants in this study. Data were collected from the medical records of the staff using the census method. For analysis of data, generalized estimating equation (GEE) regression was used. The results showed a significant difference in cholesterol levels between shift workers and day workers on the first observation (P < 0.001), yet no such difference was observed for TG (P = 0.853). Moreover, the results showed that the variables of age, work experience and BMI were not similar between shift workers and day workers. Therefore, to remove the effect of such variables, we used GEE regression. Despite the borderline difference of cholesterol between regular shift workers and day workers, this correlation was not statistically significant (P = 0.051). The results for TG also showed no correlation with shift work. According to the findings of this study, there is no relationship between shift work and changes in serum TG and cholesterol. The lack of relationship can be due to shift plans for shift workers, nutrition, or the "Healthy Heart project" at Isfahan Mobarakeh Steel Company.

Working the night shift causes increased vascular stress and delayed recovery in young women.

PubMed

Lo, Shih-Hsiang; Lin, Lian-Yu; Hwang, Jing-Shiang; Chang, Yu-Yin; Liau, Chiau-Suong; Wang, Jung-Der

2010-08-01

Shiftwork has been associated with elevated blood pressure (BP) and decreased heart-rate variability (HRV), factors that may increase the long-term risk of cardiovascular-related mortality and morbidity. This study explored the effect of shiftwork on dynamic changes in autonomic control of HRV (cardiac stress), systolic BP and diastolic BP, i.e., SBP and DBP (vascular stress), and recovery in the same subjects working different shifts. By studying the same subjects, the authors could reduce the effect of possible contribution of between-subject variation from genetic predisposition and environmental factors. The authors recruited 16 young female nurses working rotating shifts--day (08:00-16:00 h), evening (16:00-00:00 h), and night (00:00-08:00 h)--and 6 others working the regular day shift. Each nurse received simultaneous and repeated 48-h ambulatory electrocardiography and BP monitoring during their work day and the following off-duty day. Using a linear mixed-effect model to adjust for day shift, the results of the repeated-measurements and self-comparisons found significant shift differences in vascular stress. While working the night shift, the nurses showed significant increases in vascular stress, with increased SBP of 9.7 mm Hg. The changes of SBP and DBP seemed to peak during waking time at the same time on the day off as they did on the working day. Whereas HRV profiles usually returned to baseline level after each shift, the SBP and DBP of night-shift workers did not completely return to baseline levels the following off-duty day (p < .001). The authors concluded that although the nurses may recover from cardiac stress the first day off following a night shift, they do not completely recover from increases in vascular stress on that day.

[Relationship between fatigue recovery after late-night shifts and stress relief awareness].

PubMed

Kakamu, Takeyasu; Tsuji, Masayoshi; Hidaka, Tomoo; Kumagai, Tomohiro; Hayakawa, Takehito; Fukushima, Tetsuhito

2014-01-01

To examine the factors related to fatigue accumulation by irregular shift workers after the late-night shift. We studied employees of a company in the transportation industry in Fukushima prefecture. The company transports passengers, and many employees, including the crew, engage in irregular shift work. We performed the investigation by using a self-administered questionnaire which was sent to 89 employees in October, 2011. Of the 89 who were given the survey, 84 replied, and 52 of those employees had worked the late-night shift (straddling midnight) at least once during September. In answer to the question "How long does it take you to recover after working the late-night-shift?" choices were "I don't feel tired ", "I recover the next day", "I recover in two or three days", and "It takes more than three days". We classified the choices into two groups of: 1) "I don't feel tired" and "I recover the next day", and 2) "I recover in two or three days" and "It takes more than three days". Other questions were asked about age, BMI, weekday average duration of sleep, whether or not a nap was taken before the late-night shift, risk of lifestyle-related diseases (hypertension, dyslipidemia, and diabetes), awareness of life stress accumulation, and exercise habits. Thirty-two employees answered that they recovered from the late-night shift by the next day, whereas 20 employees answered that it took more than 2 days to recover after the late-night-shift. The group who answered that recovery time after the late-night shift took more than 2 days significantly (p=0.035) felt that their stress management was insufficient. Age, BMI, weekday average duration of sleep, whether or not a nap was taken before the late-night shifts, risk of lifestyle-related diseases, and exercise habits showed no significant association with fatigue accumulation. The group who answered that their stress management was insufficient significantly chose liquor (p=0.045) and cigarettes (p=0.030) for stress reduction. In this study, a relationship was recognized between degree of awareness of daily stress relief and fatigue recovery period. In addition, various means of stress relief had different effects, suggesting the need for individualized mental health care.

Complete or partial circadian re-entrainment improves performance, alertness, and mood during night-shift work.

PubMed

Crowley, Stephanie J; Lee, Clara; Tseng, Christine Y; Fogg, Louis F; Eastman, Charmane I

2004-09-15

To assess performance, alertness, and mood during the night shift and subsequent daytime sleep in relation to the degree of re-alignment (re-entrainment) of circadian rhythms with a night-work, day-sleep schedule. Subjects spent 5 consecutive night shifts (11:00 pm-7:00 am) in the lab and slept at home in darkened bedrooms (8:30 am-3:30 pm). Subjects were categorized by the degree of re-entrainment attained after the 5 night shifts. Completely re-entrained: temperature minimum in the second half of daytime sleep; partially re-entrained: temperature minimum in the first half of daytime sleep; not re-entrained: temperature minimum did not delay enough to reach daytime sleep. See above. Young healthy adults (n = 67) who were not shift workers. Included bright light during the night shifts, sunglasses worn outside, a fixed dark daytime sleep episode, and melatonin. The effects of various combinations of these interventions on circadian re-entrainment were previously reported. Here we report how the degree of re-entrainment affected daytime sleep and measures collected during the night shift. Salivary melatonin was collected every 30 minutes in dim light (<20 lux) before and after the night shifts to determine the dim light melatonin onset, and the temperature minimum was estimated by adding a constant (7 hours) to the dim light melatonin onset. Subjects kept sleep logs, which were verified by actigraphy. The Neurobehavioral Assessment Battery was completed several times during each night shift. Baseline sleep schedules and circadian phase differed among the 3 re-entrainment groups, with later times resulting in more re-entrainment. The Neurobehavioral Assessment Battery showed that performance, sleepiness, and mood were better in the groups that re-entrained compared to the group that did not re-entrain, but there were no significant differences between the partial and complete re-entrainment groups. Subjects slept almost all of the allotted 7 hours during the day, and duration did not significantly differ among the re-entrainment groups. In young people, complete re-entrainment to the night-shift day-sleep schedule is not necessary to produce substantial benefits in neurobehavioral measures; partial re-entrainment (delaying the temperature minimum into the beginning of daytime sleep) is sufficient. The group that did not re-entrain shows that a reasonable amount of daytime sleep is not enough to produce good neurobehavioral performance during the night shift. Therefore, some re-alignment of circadian rhythms is recommended.

Use of a Night Float System to Comply With Resident Duty Hours Restrictions: Perceptions of Workplace Changes and Their Effects on Professionalism.

PubMed

Sun, Ning-Zi; Gan, Runye; Snell, Linda; Dolmans, Diana

2016-03-01

Although some evidence suggests that resident duty hours reforms can lead to shift-worker mentality and loss of patient ownership, other evidence links long hours and fatigue to poor work performance and loss of empathy, suggesting the restrictions could positively affect professionalism. The authors explored perceived impacts of a 16-hour duty restriction, achieved using a night float (NF) system, on the workplace and professionalism. In 2013, the authors conducted semistructured interviews with 18 residents, 9 staff physicians, and 3 residency program directors in the McGill University core internal medicine residency program regarding their perceptions of the program's 12-hour shift-based NF system. Interviews were transcribed and coded for common themes. The authors used a descriptive qualitative methodology. Participants viewed implementation of the NF system as leading to decreased physical and mental exhaustion, more consistent interaction with patients, and more stable team structure within shifts compared with the previous 24-hour call system. These workplace changes were felt to improve teamwork and patient ownership within shifts, quality of work performed, and empathy. Across shifts, however, more frequent sign-overs, stricter application of shift time boundaries, and loose integration between daytime and NF teams were perceived as leading to emergence of shift-worker mentality around sign-over. Perceptions of optimal patient ownership changed from the traditional single-physician-24/7 model to team-based shared ownership. Duty hours restrictions, as exemplified by an NF system, have both positive and negative impacts on professionalism. Interventions and training toward effective team-based care are needed to curb emergence of shift-worker mentality.

Coping with shift work-related circadian disruption: A mixed-methods case study on napping and caffeine use in Australian nurses and midwives.

PubMed

Centofanti, Stephanie; Banks, Siobhan; Colella, Antonietta; Dingle, Caroline; Devine, Lisa; Galindo, Helen; Pantelios, Sophie; Brkic, Gorjana; Dorrian, Jillian

2018-05-15

Two of the most ubiquitous fatigue countermeasures used by shift-working nurses are napping and caffeine. This mixed-methods case study investigated the ways nurses and midwives utilised napping and caffeine countermeasures to cope with shift work, and associated sleep, physical health and psychological health outcomes. N = 130 Australian shift-working nurses and midwives (mean age = 44 years, range = 21-67, 115F, 15M) completed the Standard Shiftwork Index. A sub-set of 22 nurses and midwives completed an in-depth interview. Nearly 70% of participants reported napping. Those who napped during night shifts had significantly less total sleep time before (F 2,75  = 5.5, p < 0.01) and between days off (F 2,82  = 3.9, p < 0.05). By the end of the night shift, average hours of time awake were significantly less for prophylactic and on-shift nappers compared to non-nappers (F 2,85  = 97.2, p < 0.001). Since starting shift work, the percentage of high caffeine consumers (>400 mg/day) increased from 15% to 33% of the sample and an average of 4 (SD = 2) caffeinated beverages per day was reported. Increased caffeine consumption was associated with greater sleep disturbance (r = 0.26, p < 0.05), psychological distress (r = 0.37, p < 0.001), abdomen pain (r = 0.27, p < 0.05) and weight gain since starting shift work (r = 0.25, p < 0.05). Interviews confirmed these relationships and revealed that caffeine consumption on night shift was common, whereas napping on night shift was dependent on a number of factors including ability to sleep during the day. This study identified reasons shift workers chose to engage in or abstain from napping and consuming caffeine, and how these strategies related to poor sleep and health outcomes. Further research is required to help develop recommendations for shift workers regarding napping and caffeine consumption as fatigue countermeasures, whilst taking into account the associated hazards of each strategy.

Does Current Scientific Evidence Support a Link Between Light at Night and Breast Cancer Among Female Night-Shift Nurses?

PubMed Central

Dickerman, Barbra; Liu, Jianghong

2014-01-01

Breast cancer is increasingly prevalent in industrialized regions of the world, and exposure to light at night (LAN) has been proposed as a potential risk factor. Epidemiological observations have documented an increased breast cancer risk among female night-shift workers, and strong experimental evidence for this relationship has also been found in rodent models. Indirect support for the LAN hypothesis comes from studies involving blind women, sleep duration, bedroom light levels, and community nighttime light levels. This article reviews the literature, discusses possible mechanisms of action, and provides recommendations for occupational health nursing research, practice, and education. Research is needed to further explore the relationship between exposure to LAN and breast cancer risk and elucidate the mechanisms underlying this relationship before interventions can be designed for prevention and mitigation of breast cancer. PMID:22658734

Sleep and need for recovery in shift workers: do chronotype and age matter?

PubMed

van de Ven, Hardy A; van der Klink, Jac J L; Vetter, Céline; Roenneberg, Till; Gordijn, Marijke; Koolhaas, Wendy; de Looze, Michiel P; Brouwer, Sandra; Bültmann, Ute

2016-01-01

This study examined associations of chronotype and age with shift-specific assessments of main sleep duration, sleep quality and need for recovery in a cross-sectional study among N = 261 industrial shift workers (96.6% male). Logistic regression analyses were used, adjusted for gender, lifestyle, health, nap behaviour, season of assessment and shift schedule. Shift workers with latest versus earliest chronotype reported a shorter sleep duration (OR 11.68, 95% CI 3.31-41.17) and more awakenings complaints (OR 4.84, 95% CI 4.45-11.92) during morning shift periods. No associations were found between chronotype, sleep and need for recovery during evening and night shift periods. For age, no associations were found with any of the shift-specific outcome measures. The results stress the importance of including the concept of chronotype in shift work research and scheduling beyond the concept of age. Longitudinal research using shift-specific assessments of sleep and need for recovery are needed to confirm these results. Chronotype seems to better explain individual differences in sleep than age. In view of ageing societies, it might therefore be worthwhile to further examine the application of chronotype for individualised shift work schedules to facilitate healthy and sustainable employment.

Shift work, night work and sleep disorders among pastry cookers and shopkeepers in France: a cross-sectional survey

PubMed Central

Pepin, Emilie; Gillet, Pascal; Sauvet, Fabien; Gomez-Merino, Danielle; Thaon, Isabelle; Chennaoui, Mounir; Leger, Damien

2018-01-01

Objective Most research on night and shift work focuses on employee health in large companies, primarily in the healthcare and transportation sectors. However, many night workers work on their own or in small businesses related to services or food. This survey focuses on sleep habits and disorders concerning night work in pastry production and sales. Methods An epidemiological telephone cross-sectional survey of night shift workers and their sleep habits was proposed to all employers and employees in the French pastry industry via their insurance health prevention company. Sleep logs allow us to estimate the total sleep time (TST) on workdays and enquire on napping episodes and length. In order to estimate the ideal TST, we added a question on the ideal amount of sleep the subjects need to be in good shape in the morning. We also define sleep debt as the difference between the ideal TST and TST on workdays, and considered a sleep debt when the difference was above 60 min and severe sleep debt above 90 min. Finally we retained subjects as long sleepers for those with a TSTof more than 7 hours and short sleepers when TST was under 5 hours. Insomnia, sleepiness and sleep apnoea have been defined based on the International Classification of Sleep Disorders-Third Edition and the classification of mental disorders (Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition). Bivariate and multivariate logistic regression models were applied to investigate the association with short TST, long TST, sleep debt and napping. Results We analysed 2622 complete questionnaires from 1313 men and 1309 women aged 22–50 years old. 1397 workers began work before 07:00, whereas 1225 began later. The 24-hour TST was 6.7±1.4 hours, whereas the ideal TST was 7.0±1.2 hours. Severe sleep debt (>90 min) was reported by 6% women versus 5% men, whereas moderate sleep debt (>60 min) was reported by 11.5% women versus 9.3% men. Napping is one way to improve 24-hour TST for 58% of pastry producers (75±13 min) and 23% of shopkeepers (45±8 min). Nevertheless, 26.2% of the respondents complained of chronic insomnia, especially women aged 45–54 years old (31%). Finally, 29.6% had evocative criteria for obstructive sleep apnoea, although only 9.1% had a high score on the Berlin Questionnaire. Conclusion Our study demonstrates that both pastry producers and shopkeepers can have disturbed sleep schedules and a high prevalence of sleep disorders, although many have used napping as a behavioural countermeasure to fight sleep debt. The results of our survey lead us to conclude that, besides the need to take care of night workers in big industries, more information and occupational prevention must be focused on night workers in individual and small businesses. PMID:29743318

Simulated Night Shift Disrupts Circadian Rhythms of Immune Functions in Humans.

PubMed

Cuesta, Marc; Boudreau, Philippe; Dubeau-Laramée, Geneviève; Cermakian, Nicolas; Boivin, Diane B

2016-03-15

Recent research unveiled a circadian regulation of the immune system in rodents, yet little is known about rhythms of immune functions in humans and how they are affected by circadian disruption. In this study, we assessed rhythms of cytokine secretion by immune cells and tested their response to simulated night shifts. PBMCs were collected from nine participants kept in constant posture over 24 h under a day-oriented schedule (baseline) and after 3 d under a night-oriented schedule. Monocytes and T lymphocytes were stimulated with LPS and PHA, respectively. At baseline, a bimodal rhythmic secretion was detected for IL-1β, IL-6, and TNF-α: a night peak was primarily due to a higher responsiveness of monocytes, and a day peak was partly due to a higher proportion of monocytes. A rhythmic release was also observed for IL-2 and IFN-γ, with a nighttime peak due to a higher cell count and responsiveness of T lymphocytes. Following night shifts, with the exception of IL-2, cytokine secretion was still rhythmic but with peak levels phase advanced by 4.5-6 h, whereas the rhythm in monocyte and T lymphocyte numbers was not shifted. This suggests distinct mechanisms of regulation between responsiveness to stimuli and cell numbers of the human immune system. Under a night-oriented schedule, only cytokine release was partly shifted in response to the change in the sleep-wake cycle. This led to a desynchronization of rhythmic immune parameters, which might contribute to the increased risk for infection, autoimmune diseases, cardiovascular and metabolic disorders, and cancer reported in shift workers. Copyright © 2016 by The American Association of Immunologists, Inc.

Change from an 8-hour shift to a 12-hour shift, attitudes, sleep, sleepiness and performance.

PubMed

Lowden, A; Kecklund, G; Axelsson, J; Akerstedt, T

1998-01-01

The present study sought to evaluate the effect of a change from a rotating 3-shift (8-hour) to a 2-shift shift (12 hour) schedule on sleep, sleepiness, performance, perceived health, and well-being. Thirty-two shift workers at a chemical plant (control room operators) responded to a questionnaire a few months before a change was made in their shift schedule and 10 months after the change. Fourteen workers also filled out a diary, carried activity loggers, and carried out reaction-time tests (beginning and end of shift). Fourteen day workers served as a reference group for the questionnaires and 9 were intensively studied during a week with workdays and a free weekend. The questionnaire data showed that the shift change increased satisfaction with workhours, sleep, and time for social activities. Health, perceived accident risk, and reaction-time performance were not negatively affected. Alertness improved and subjective recovery time after night work decreased. The quick changes in the 8-hour schedule greatly increased sleep problems and fatigue. Sleepiness integrated across the entire shift cycle showed that the shift workers were less alert than the day workers, across workdays and days off (although alertness increased with the 12-hour shift). The change from 8-hour to 12-hour shifts was positive in most respects, possibly due to the shorter sequences of the workdays, the longer sequences of consecutive days off, the fewer types of shifts (easier planning), and the elimination of quick changes. The results may differ in groups with a higher work load.

Effect of Shift Work on Sleep, Health, and Quality of Life of Health-care Workers.

PubMed

Nena, Evangelia; Katsaouni, Maria; Steiropoulos, Paschalis; Theodorou, Evangelos; Constantinidis, Theodoros C; Tripsianis, Grigorios

2018-01-01

Shift work is associated with sleep disruption, impaired quality of life, and is a risk factor for several health conditions. Aim of this study was to investigate the impact of shift work on sleep and quality of life of health-care workers (HCW). Tertiary University hospital in Greece. Cross-sectional study. Included were HCW, working either in an irregular shift system or exclusively in morning shifts. All participants answered the WHO-5 Well-Being Index (WHO-5) and a questionnaire on demographics and medical history. Shift workers filled the Shift Work Disorders Screening Questionnaire (SWDSQ). Descriptive statistics, Student's t -test, one-way analysis of variance (ANOVA), Pearson's r correlation coefficient, and multivariate stepwise linear regression analysis were applied. Included were 312 employees (87.9% females), 194 working in irregular shift system and 118 in morning shifts. Most shift-workers (58.2%) were somehow or totally dissatisfied with their sleep quality. Regression analysis revealed the following independent determinants for sleep impairment: parenthood ( P < 0.001), age 36-45 years ( P < 0.001), >3 night shifts/week ( P < 0.001), work >5 years in an irregular shift system ( P < 0.001). Diabetes mellitus was the most common medical condition reported by shift workers ( P = 0.008). Comparison between the two groups revealed a significantly impairment in WHO-5 total score, as well as in 4 of 5 of its items ( P < 0.001). Shift-work impairs quality of life, whereas its duration and frequency, along with age and family status of employees can have adverse effects on sleep.

Associations between employees' work schedules and the vocational consequences of workplace injuries.

PubMed

Dembe, Allard E; Delbos, Rachel; Erickson, J Bianca; Banks, Steven M

2007-12-01

This study examines the effect of long-hour work schedules and nonstandard shift work (e.g., night and evening shifts) on the ability of injured workers to maintain productive employment following a workplace injury. Analyses were based on 13 years of data from the National Longitudinal Survey of Youth. Multivariate logistic regression analyses were performed with one of ten nonstandard schedules as the independent variable and a particular vocational consequences as the dependent variable. Vocational consequences included being unable to perform normal job duties, temporary job reassignment, working less than full time, filing a workers' compensation claim, and quitting or being fired because of the injury. Covariates in the regression model included age, gender, occupation, industry, and region. The most prominent effects of working a nonstandard schedule were a increased risk of being fired (OR = 1.81; 1.15-2.90 CI 95%), quitting (OR = 1.68; 1.20-2.36 CI 95%), or being unable to work full time (OR = 1.33; 1.08-1.64 CI 95%) following an injury, compared to injured workers in conventional schedules. Schedules involving overtime and long working hours generally had a greater impact on vocational consequences following a workplace injury than did schedules involving night, evening, and other nonstandard shift work. Occupational rehabilitation professionals need to consider the specific type of work schedule when developing effective return-to-work plans for injured workers. Special precautions need to be taken for workers returning to schedules that involve more than 12 h per day, 60 h per week, and long commutes.

A 12 year prospective study of circulatory disease among Danish shift workers.

PubMed

Tüchsen, F; Hannerz, H; Burr, H

2006-07-01

Previous studies of the risk of heart disease after shift work reached different estimates and review authors disagree about the validity of some of the studies. A cross sectional study showed that shift workers had a higher prevalence of nearly every unfavourable work environment factor investigated. Conflicts at work and low decision latitude were more frequent among shift workers, and all-day walking or standing work and part-time jobs were more often found among female shift workers. To estimate the risk of circulatory disease in a prospective follow up of a representative sample of gainfully employed Danes, considering known or suspected confounding factors. A cohort of 5517 people who were gainfully employed in 1990 were followed up for all hospital treatments due to circulatory diseases (390-458, ICD-8; I00-I99, ICD-10) from 1991 to 2002 inclusive. A log linear Poisson regression model was applied to control confounding factors and calculate the relative risk for 927 men and women working nights, evenings, or other non-day shifts compared to 4579 day workers. Non-day workers compared to day workers had a relative risk (RR) for all circulatory diseases of 1.31 (95% CI 1.06-1.63). Without control for BMI and smoking, the RR estimate was 1.33 (95% CI 1.07-1.65). For a subgroup of workers with at least three years' seniority, the RR was 1.40 (95% CI 1.09-1.81). The population based aetiological fraction of shift work was estimated to 5%. This study adds to a growing body of evidence suggesting that shift work carries an excess risk of circulatory diseases.

Shift Work and Occupational Stress in Police Officers

PubMed Central

Ma, Claudia C.; Andrew, Michael E.; Fekedulegn, Desta; Gu, Ja K.; Hartley, Tara A.; Charles, Luenda E.; Violanti, John M.; Burchfiel, Cecil M.

2014-01-01

Background Shift work has been associated with occupational stress in health providers and in those working in some industrial companies. The association is not well established in the law enforcement workforce. Our objective was to examine the association between shift work and police work-related stress. Methods The number of stressful events that occurred in the previous month and year was obtained using the Spielberger Police Stress Survey among 365 police officers aged 27–66 years. Work hours were derived from daily payroll records. A dominant shift (day, afternoon, or night) was defined for each participant as the shift with the largest percentage of total time a participant worked (starting time from 4:00 AM to 11:59 AM, from 12 PM to 7:59 PM, and from 8:00 PM to 3:59 AM for day, afternoon, and night shift, respectively) in the previous month or year. Analysis of variance and covariance were used to examine the number of total and subscale (administrative/professional pressure, physical/psychological danger, or organizational support) stressful events across the shift. Results During the previous month and year, officers working the afternoon and night shifts reported more stressful events than day shift officers for total stress, administrative/professional pressure, and physical/psychological danger (p < 0.05). These differences were independent of age, sex, race/ethnicity, and police rank. The frequency of these stressful events did not differ significantly between officers working the afternoon and night shifts. Conclusion Non–day shift workers may be exposed to more stressful events in this cohort. Interventions to reduce or manage police stress that are tailored by shift may be considered. PMID:25830066

Shift Work and Cognitive Flexibility: Decomposing Task Performance.

PubMed

Cheng, Philip; Tallent, Gabriel; Bender, Thomas John; Tran, Kieulinh Michelle; Drake, Christopher L

2017-04-01

Deficits in cognitive functioning associated with shift work are particularly relevant to occupational performance; however, few studies have examined how cognitive functioning is associated with specific components of shift work. This observational study examined how circadian phase, nocturnal sleepiness, and daytime insomnia in a sample of shift workers ( N = 30) were associated with cognitive flexibility during the night shift. Cognitive flexibility was measured using a computerized task-switching paradigm, which produces 2 indexes of flexibility: switch cost and set inhibition. Switch cost represents the additional cognitive effort required in switching to a different task and can impact performance when multitasking is involved. Set inhibition is the efficiency in returning to previously completed tasks and represents the degree of cognitive perseveration, which can lead to reduced accuracy. Circadian phase was measured via melatonin assays, nocturnal sleepiness was assessed using the Multiple Sleep Latency Test, and daytime insomnia was assessed using the Insomnia Severity Index. Results indicated that those with an earlier circadian phase, insomnia, and sleepiness exhibited reduced cognitive flexibility; however, specific components of cognitive flexibility were differentially associated with circadian phase, insomnia, and sleepiness. Individuals with an earlier circadian phase (thus more misaligned to the night shift) exhibited larger switch costs, which was also associated with reduced task efficiency. Shift workers with more daytime insomnia demonstrated difficulties with cognitive inhibition, whereas nocturnal sleepiness was associated with difficulties in reactivating previous tasks. Deficits in set inhibition were also related to reduced accuracy and increased perseverative errors. Together, this study indicates that task performance deficits in shift work are complex and are variably impacted by different mechanisms. Future research may examine phenotypic differences in shift work and the associated consequences. Results also suggest that fatigue risk management strategies may benefit from increased scope and specificity in assessment of sleep, sleepiness, and circadian rhythms in shift workers.

Anxiety about starting three-shift work among female workers: findings from the Female Shift Workers' Health Study.

PubMed

Kubo, Tatsuhiko; Maruyama, Takashi; Shirane, Kiyoyumi; Otomo, Hajime; Matsumoto, Tetsuro; Oyama, Ichiro

2008-03-01

In 1999, the Japanese Law on Equal Employment Opportunity and Conditions was amended and the previous prohibition of the assignment of female workers to night work was abolished. Subsequently, the number of female shift workers has been increasing in Japan, necessitating greater attention to the health care of this population. The aim of the current study is to evaluate the relationship between anxiety expressed about starting three-shift work and background characteristics among female workers who were being assigned to three-shift work for the first time. The subjects were 38 middle-aged female workers (age range: 44 to 59 years) who were working at a chemical plant. The women completed a self-administered questionnaire before starting three-shift work. Levels of anxiety about starting three-shift work were assessed by the question 'Do you feel anxious about starting three-shift work?' The available responses were: 'Very agree', 'Considerably agree', 'Rather agree', 'Slightly agree' and 'Not agree at all', and 63% of the subjects gave one of the first two answers, which were defined as indicating anxiety. We also acquired information regarding lifestyle and occupation for each subject, including the following factors: frequency of breakfast consumption, subjective sleep insufficiency, previous experience of similar work before beginning shift work, previous experience of two-shift work, and responsibility for household duties. In the study, we found a marginally statistically significant trend association between frequent breakfast consumption and anxiety about starting three-shift work (P(trend) = 0.09). Anxiety was also high among subjects with sleep disorders, especially those suffering from subjective sleep insufficiency (P = 0.08). Due to the small study population, these results should be interpreted with caution and confirmed by future studies.

Shift work, job strain and changes in the body mass index among women: a prospective study.

PubMed

Fujishiro, Kaori; Lividoti Hibert, Eileen; Schernhammer, Eva; Rich-Edwards, Janet W

2017-06-01

The effects of job strain and shift work on weight gain have not been studied jointly. Cross-sectional and longitudinal studies on shift work and weight gain have reported different results. This study examines potential effect modification by job strain on the link between shift work and weight gain, and concurrent and delayed effects of shift work on weight gain. Data came from 52 622 women who participated in the Nurses' Health Study II, a prospective cohort study. Using linear regression, we modelled change in body mass index (BMI) over 4 years as a function of change in job strain, cumulative exposure to rotating night shift previously and during the 4 years (ie, previous and concurrent exposures) and the interaction between job strain and concurrent shift work exposure. Age, race/ethnicity, pregnancy history, baseline BMI, job types and health behaviours at baseline were controlled for. Job strain and rotating shift work, concurrent and previous, all had independent associations with BMI change during the 4-year period. There was no evidence for effect modification by job strain. Concurrent and previous exposures to rotating night shift had different associations with BMI change: an inverted U-shape for concurrent exposure (ranging from 0.01 to 0.14 kg/m 2 increase), a dose-response for previous exposure (-0.02 to 0.09 kg/m 2 ). Job strain and rotating night shift work have independent contributions to weight gain. Reducing job strain and supporting night shift workers are both important intervention goals. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Meal composition and shift work performance.

PubMed

Love, Heather L; Watters, Corilee A; Chang, Wei-Ching

2005-01-01

Research indicates that the ability to perform a task can be affected by the composition of the meal preceding the task. This study investigated the effect of shift workers' consumption of a medium-fat, medium-carbohydrate meal on alertness scores. Six subjects (four men, two women) aged 19 to 44 recorded food intake, sleep, and quality of sleep for two weeks, and measured their body temperature and performed cognitive tests during two night shifts at baseline and in test periods. The Stanford Sleepiness Scale (SSS) was used to quantify sleepiness, and a Paced Auditory Serial Addition Test (PASAT) was used to measure cognitive performance. In comparison with the score at baseline, when subjects had a low-fat, high-carbohydrate dietary intake (1,335 kcal/5,588 kJ, 56% carbohydrate, 28% fat), the 1.6-second PASAT score improved significantly (p=0.042) during night shifts when subjects consumed a test meal (987 kcal/4,131 kJ, 46% carbohydrate, 42% fat). No statistically significant difference in SSS was found between baseline and test periods. The reduced body temperature between 2400 hours and 0530 hours was similar for both baseline and test periods. Meal composition and size during night shifts may affect cognitive performance.

The association between weekly work hours, crew familiarity, and occupational injury and illness in emergency medical services workers.

PubMed

Weaver, Matthew D; Patterson, P Daniel; Fabio, Anthony; Moore, Charity G; Freiberg, Matthew S; Songer, Thomas J

2015-12-01

Emergency Medical Services (EMS) workers are shift workers in a high-risk, uncontrolled occupational environment. EMS-worker fatigue has been associated with self-reported injury, but the influence of extended weekly work hours is unknown. A retrospective cohort study was designed using historical shift schedules and occupational injury and illness reports. Using multilevel models, we examined the association between weekly work hours, crew familiarity, and injury or illness. In total, 966,082 shifts and 950 reports across 14 EMS agencies were obtained over a 1-3 year period. Weekly work hours were not associated with occupational injury or illness. Schedule characteristics that yield decreased exposure to occupational hazards, such as part-time work and night work, conferred reduced risk of injury or illness. Extended weekly work hours were not associated with occupational injury or illness. Future work should focus on transient exposures and agency-level characteristics that may contribute to adverse work events. © 2015 Wiley Periodicals, Inc.

[Sleep quality of nurses working in shifts - Hungarian adaptation of the Bergen Shift Work Sleep Questionnaire].

PubMed

Fusz, Katalin; Tóth, Ákos; Fullér, Noémi; Müller, Ágnes; Oláh, András

2015-12-06

Sleep disorders among shift workers are common problems due to the disturbed circadian rhythm. The Bergen Shift Work Sleep Questionnaire assesses discrete sleep problems related to work shifts (day, evening and night shifts) and rest days. The aim of the study was to develop the Hungarian version of this questionnaire and to compare the sleep quality of nurses in different work schedules. 326 nurses working in shifts filled in the questionnaire. The authors made convergent and discriminant validation of the questionnaire with the Athens Insomnia Scale and the Perceived Stress Questionnaire. The questionnaire based on psychometric characteristics was suitable to assess sleep disorders associated with shift work in a Hungarian sample. The frequency of discrete symptoms significantly (p<0.001) differed with the shifts. Nurses experienced the worst sleep quality and daytime fatigue after the night shift. Nurses working in irregular shift system had worse sleep quality than nurses working in regular and flexible shift system (p<0.001). The sleep disorder of nurses working in shifts should be assessed with the Hungarian version of the Bergen Shift Work Sleep Questionnaire on a nationally representative sample, and the least burdensome shift system could be established.

Sleep Loss and Fatigue in Shift Work and Shift Work Disorder

PubMed Central

Åkerstedt, Torbjörn; Wright, Kenneth P.

2010-01-01

Shift work is highly prevalent in industrialized societies (>20%) but, when it includes night work, it has pronounced negative effects on sleep, subjective and physiological sleepiness, performance, accident risk, as well as on health outcomes such as cardiovascular disease and certain forms of cancer. The reason is the conflict between the day oriented circadian physiology and the requirement for work and sleep at the “wrong” biological time of day. Other factors that negatively impact work shift sleepiness and accident risk include long duration shifts greater than 12 hours and individual vulnerability for phase intolerance that may lead to a diagnosis of shift work disorder; i.e., those shift workers with the greatest sleepiness and performance impairment during the biological night and insomnia during the biological day. Whereas some countermeasures may be used to ameliorate the negative impact of shift work on nighttime sleepiness and daytime insomnia (combined countermeasures may be the best available), there seems at present to be no way to eliminate most of the negative effects of shift work on human physiology and cognition. PMID:20640236

Quick returns and night work as predictors of sleep quality, fatigue, work-family balance and satisfaction with work hours.

PubMed

Dahlgren, Anna; Tucker, Philip; Gustavsson, Petter; Rudman, Ann

2016-01-01

Quick returns (intervals of <11 h between the end of one shift and the start of the next) are associated with short sleeps and fatigue on the subsequent shift. Recent evidence suggests that shift workers regard quick returns as being more problematic than night work. The current study explored quick returns and night work in terms of their impact on sleep, unwinding, recovery, exhaustion, satisfaction with work hours and work-family interference. Data from the 2006 cohort of Swedish nursing students within the national Longitudinal Analysis of Nursing Education (LANE) study were analysed (N = 1459). Respondents completed a questionnaire prior to graduation (response rate 69.2%) and 3 years after graduation (65.9%). The analyses examined associations between frequency of quick returns and night work and measures taken in year three, while adjusting for confounding factors (in year three and prior graduation). Frequency of quick returns was a significant predictor of poor sleep quality, short sleeps, unwinding, exhaustion, satisfaction with work hours and work-to-family interference, with higher frequency predicting more negative outcomes. Quick returns did not predict recovery after rest days. Frequency of night work did not predict any of the outcomes. In conclusion, quick returns were an important determinant of sleep, recovery and wellbeing, whereas night work did not show such an association.

Person-directed, non-pharmacological interventions for sleepiness at work and sleep disturbances caused by shift work.

PubMed

Slanger, Tracy E; Gross, J Valérie; Pinger, Andreas; Morfeld, Peter; Bellinger, Miriam; Duhme, Anna-Lena; Reichardt Ortega, Rosalinde Amancay; Costa, Giovanni; Driscoll, Tim R; Foster, Russell G; Fritschi, Lin; Sallinen, Mikael; Liira, Juha; Erren, Thomas C

2016-08-23

Shift work is often associated with sleepiness and sleep disorders. Person-directed, non-pharmacological interventions may positively influence the impact of shift work on sleep, thereby improving workers' well-being, safety, and health. To assess the effects of person-directed, non-pharmacological interventions for reducing sleepiness at work and improving the length and quality of sleep between shifts for shift workers. We searched CENTRAL, MEDLINE Ovid, Embase, Web of Knowledge, ProQuest, PsycINFO, OpenGrey, and OSH-UPDATE from inception to August 2015. We also screened reference lists and conference proceedings and searched the World Health Organization (WHO) Trial register. We contacted experts to obtain unpublished data. Randomised controlled trials (RCTs) (including cross-over designs) that investigated the effect of any person-directed, non-pharmacological intervention on sleepiness on-shift or sleep length and sleep quality off-shift in shift workers who also work nights. At least two authors screened titles and abstracts for relevant studies, extracted data, and assessed risk of bias. We contacted authors to obtain missing information. We conducted meta-analyses when pooling of studies was possible. We included 17 relevant trials (with 556 review-relevant participants) which we categorised into three types of interventions: (1) various exposures to bright light (n = 10); (2) various opportunities for napping (n = 4); and (3) other interventions, such as physical exercise or sleep education (n = 3). In most instances, the studies were too heterogeneous to pool. Most of the comparisons yielded low to very low quality evidence. Only one comparison provided moderate quality evidence. Overall, the included studies' results were inconclusive. We present the results regarding sleepiness below. Bright light Combining two comparable studies (with 184 participants altogether) that investigated the effect of bright light during the night on sleepiness during a shift, revealed a mean reduction 0.83 score points of sleepiness (measured via the Stanford Sleepiness Scale (SSS) (95% confidence interval (CI) -1.3 to -0.36, very low quality evidence). Another trial did not find a significant difference in overall sleepiness on another sleepiness scale (16 participants, low quality evidence).Bright light during the night plus sunglasses at dawn did not significantly influence sleepiness compared to normal light (1 study, 17 participants, assessment via reaction time, very low quality evidence).Bright light during the day shift did not significantly reduce sleepiness during the day compared to normal light (1 trial, 61 participants, subjective assessment, low quality evidence) or compared to normal light plus placebo capsule (1 trial, 12 participants, assessment via reaction time, very low quality evidence). Napping during the night shiftA meta-analysis on a single nap opportunity and the effect on the mean reaction time as a surrogate for sleepiness, resulted in a 11.87 ms reduction (95% CI 31.94 to -8.2, very low quality evidence). Two other studies also reported statistically non-significant decreases in reaction time (1 study seven participants; 1 study 49 participants, very low quality evidence).A two-nap opportunity resulted in a statistically non-significant increase of sleepiness (subjective assessment) in one study (mean difference (MD) 2.32, 95% CI -24.74 to 29.38, 1 study, 15 participants, low quality evidence). Other interventionsPhysical exercise and sleep education interventions showed promise, but sufficient data to draw conclusions are lacking. Given the methodological diversity of the included studies, in terms of interventions, settings, and assessment tools, their limited reporting and the very low to low quality of the evidence they present, it is not possible to determine whether shift workers' sleepiness can be reduced or if their sleep length or quality can be improved with these interventions.We need better and adequately powered RCTs of the effect of bright light, and naps, either on their own or together and other non-pharmacological interventions that also consider shift workers' chronobiology on the investigated sleep parameters.

Risk-based Analysis of Construction Accidents in Iran During 2007-2011-Meta Analyze Study.

PubMed

Amiri, Mehran; Ardeshir, Abdollah; Fazel Zarandi, Mohammad Hossein

2014-04-01

The present study aimed to investigate the characteristics of occupational accidents and frequency and severity of work related accidents in the construction industry among Iranian insured workers during the years 20072011. The Iranian Social Security Organization (ISSO) accident database containing 21,864 cases between the years 2007-2011 was applied in this study. In the next step, Total Accident Rate (TRA), Total Severity Index (TSI), and Risk Factor (RF) were defined. The core of this work is devoted to analyzing the data from different perspectives such as age of workers, occupation and construction phase, day of the week, time of the day, seasonal analysis, regional considerations, type of accident, and body parts affected. Workers between 15-19 years old (TAR=13.4%) are almost six times more exposed to risk of accident than the average of all ages (TAR=2.51%). Laborers and structural workers (TAR=66.6%) and those working at heights (TAR=47.2%) experience more accidents than other groups of workers. Moreover, older workers over 65 years old (TSI=1.97%> average TSI=1.60%), work supervisors (TSI=12.20% >average TSI=9.09%), and night shift workers (TSI=1.89% >average TSI=1.47%) are more prone to severe accidents. It is recommended that laborers, young workers, weekend and night shift workers be supervised more carefully in the workplace. Use of Personal Protective Equipment (PPE) should be compulsory in working environments, and special attention should be undertaken to people working outdoors and at heights. It is also suggested that policymakers pay more attention to the improvement of safety conditions in deprived and cold western regions.

Risk-based Analysis of Construction Accidents in Iran During 2007-2011-Meta Analyze Study

PubMed Central

AMIRI, Mehran; ARDESHIR, Abdollah; FAZEL ZARANDI, Mohammad Hossein

2014-01-01

Abstract Background The present study aimed to investigate the characteristics of occupational accidents and frequency and severity of work related accidents in the construction industry among Iranian insured workers during the years 20072011. Methods The Iranian Social Security Organization (ISSO) accident database containing 21,864 cases between the years 2007-2011 was applied in this study. In the next step, Total Accident Rate (TRA), Total Severity Index (TSI), and Risk Factor (RF) were defined. The core of this work is devoted to analyzing the data from different perspectives such as age of workers, occupation and construction phase, day of the week, time of the day, seasonal analysis, regional considerations, type of accident, and body parts affected. Results Workers between 15-19 years old (TAR=13.4%) are almost six times more exposed to risk of accident than the average of all ages (TAR=2.51%). Laborers and structural workers (TAR=66.6%) and those working at heights (TAR=47.2%) experience more accidents than other groups of workers. Moreover, older workers over 65 years old (TSI=1.97%> average TSI=1.60%), work supervisors (TSI=12.20% >average TSI=9.09%), and night shift workers (TSI=1.89% >average TSI=1.47%) are more prone to severe accidents. Conclusion It is recommended that laborers, young workers, weekend and night shift workers be supervised more carefully in the workplace. Use of Personal Protective Equipment (PPE) should be compulsory in working environments, and special attention should be undertaken to people working outdoors and at heights. It is also suggested that policymakers pay more attention to the improvement of safety conditions in deprived and cold western regions. PMID:26005662

Differences between day and nonday workers in exposure to physical and psychosocial work factors in the Danish eldercare sector.

PubMed

Nabe-Nielsen, Kirsten; Tüchsen, Finn; Christensen, Karl Bang; Garde, Anne Helene; Diderichsen, Finn

2009-01-01

The possible interaction between individual and occupational risk factors, the need for meaningful intervention, and the demand for valid shift work research make the accumulation of adverse exposures at certain times of the day of special relevance with respect to occupational health. The aim of the present study was therefore to examine whether there was a clustering of detrimental work factors among female eldercare workers in fixed evening or fixed night shifts when they are compared with workers in fixed day shifts. This cross-sectional, questionnaire-based study was conducted among 4590 female health care workers in the Danish eldercare sector. The participants worked in nursing homes, in home care, or in both. They answered questions on job demands, job control, and social support, together with questions on physical and psychological violence, physical workload, and passive smoking. We found that-compared with day workers-fixed nonday workers were more exposed to low job control, low support from leaders, physical and psychological violence, and high physical demands. Nonday workers were, however, less exposed to high demands. These differences remained after control for age, job title, and workplace. Exposures in the work environment of Danish eldercare workers varied between shifts. In a research perspective these findings stress the importance of adequate adjustment for work factors when the health effects of shift work are studied. Moreover, the results underscore the need for an increased awareness of work factors of special importance among nonday workers when interventions against shiftwork-related occupational disorders are designed.

Work environment of Danish shift and day workers.

PubMed

Bøggild, H; Burr, H; Tüchsen, F; Jeppesen, H J

2001-04-01

Both shift work and other work environment factors have been shown to be related to heart disease. This study examined whether shift work is associated with other work environment factors related to heart disease in a random sample of the population. If so, shift work could be acting as a proxy for work environment differences. Data on 5940 employees in the Danish Work Environment Cohort Study from 1990 were reanalyzed. The information included work schedules [permanent day work, irregular workhours (including morning work), 2-shift or fixed evening and 3-shift or fixed night], length of workweek, physical factors (noise, heat, dust, passive smoking, walking, standing and monotonous repetitive tasks), and psychosocial factors (including demands and control dimensions, social support, conflicts and job insecurity). At least 1 group of shift workers had a higher prevalence of nearly every unfavorable work environment factor investigated. Exceptions were dust exposure and quantitative demands. Especially conflicts at work and low decision latitude were higher among all the groups of shift workers, and all-day walking or standing work and part-time jobs were more often found among female shift workers. The 3 different shiftwork groups were exposed to different parts of the work environment, and also men and women in shift work differed in relation to the work environment. Age and social class influenced the relationship, but not in any particular pattern. In a heterogenous population shift work was found to be associated with other work environment factors suspected to cause heart disease.

Shift work, night work and sleep disorders among pastry cookers and shopkeepers in France: a cross-sectional survey.

PubMed

Pepin, Emilie; Gillet, Pascal; Sauvet, Fabien; Gomez-Merino, Danielle; Thaon, Isabelle; Chennaoui, Mounir; Leger, Damien

2018-05-09

Most research on night and shift work focuses on employee health in large companies, primarily in the healthcare and transportation sectors. However, many night workers work on their own or in small businesses related to services or food. This survey focuses on sleep habits and disorders concerning night work in pastry production and sales. An epidemiological telephone cross-sectional survey of night shift workers and their sleep habits was proposed to all employers and employees in the French pastry industry via their insurance health prevention company. Sleep logs allow us to estimate the total sleep time (TST) on workdays and enquire on napping episodes and length. In order to estimate the ideal TST, we added a question on the ideal amount of sleep the subjects need to be in good shape in the morning. We also define sleep debt as the difference between the ideal TST and TST on workdays, and considered a sleep debt when the difference was above 60 min and severe sleep debt above 90 min. Finally we retained subjects as long sleepers for those with a TSTof more than 7 hours and short sleepers when TST was under 5 hours. Insomnia, sleepiness and sleep apnoea have been defined based on the International Classification of Sleep Disorders-Third Edition and the classification of mental disorders (Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition). Bivariate and multivariate logistic regression models were applied to investigate the association with short TST, long TST, sleep debt and napping. We analysed 2622 complete questionnaires from 1313 men and 1309 women aged 22-50 years old. 1397 workers began work before 07:00, whereas 1225 began later. The 24-hour TST was 6.7±1.4 hours, whereas the ideal TST was 7.0±1.2 hours. Severe sleep debt (>90 min) was reported by 6% women versus 5% men, whereas moderate sleep debt (>60 min) was reported by 11.5% women versus 9.3% men. Napping is one way to improve 24-hour TST for 58% of pastry producers (75±13 min) and 23% of shopkeepers (45±8 min). Nevertheless, 26.2% of the respondents complained of chronic insomnia, especially women aged 45-54 years old (31%). Finally, 29.6% had evocative criteria for obstructive sleep apnoea, although only 9.1% had a high score on the Berlin Questionnaire. Our study demonstrates that both pastry producers and shopkeepers can have disturbed sleep schedules and a high prevalence of sleep disorders, although many have used napping as a behavioural countermeasure to fight sleep debt. The results of our survey lead us to conclude that, besides the need to take care of night workers in big industries, more information and occupational prevention must be focused on night workers in individual and small businesses. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Health consequences of electric lighting practices in the modern world: A report on the National Toxicology Program's workshop on shift work at night, artificial light at night, and circadian disruption.

PubMed

Lunn, Ruth M; Blask, David E; Coogan, Andrew N; Figueiro, Mariana G; Gorman, Michael R; Hall, Janet E; Hansen, Johnni; Nelson, Randy J; Panda, Satchidananda; Smolensky, Michael H; Stevens, Richard G; Turek, Fred W; Vermeulen, Roel; Carreón, Tania; Caruso, Claire C; Lawson, Christina C; Thayer, Kristina A; Twery, Michael J; Ewens, Andrew D; Garner, Sanford C; Schwingl, Pamela J; Boyd, Windy A

2017-12-31

The invention of electric light has facilitated a society in which people work, sleep, eat, and play at all hours of the 24-hour day. Although electric light clearly has benefited humankind, exposures to electric light, especially light at night (LAN), may disrupt sleep and biological processes controlled by endogenous circadian clocks, potentially resulting in adverse health outcomes. Many of the studies evaluating adverse health effects have been conducted among night- and rotating-shift workers, because this scenario gives rise to significant exposure to LAN. Because of the complexity of this topic, the National Toxicology Program convened an expert panel at a public workshop entitled "Shift Work at Night, Artificial Light at Night, and Circadian Disruption" to obtain input on conducting literature-based health hazard assessments and to identify data gaps and research needs. The Panel suggested describing light both as a direct effector of endogenous circadian clocks and rhythms and as an enabler of additional activities or behaviors that may lead to circadian disruption, such as night-shift work and atypical and inconsistent sleep-wake patterns that can lead to social jet lag. Future studies should more comprehensively characterize and measure the relevant light-related exposures and link these exposures to both time-independent biomarkers of circadian disruption and biomarkers of adverse health outcomes. This information should lead to improvements in human epidemiological and animal or in vitro models, more rigorous health hazard assessments, and intervention strategies to minimize the occurrence of adverse health outcomes due to these exposures. Published by Elsevier B.V.

Periodic self-rostering in shift work: correspondence between objective work hours, work hour preferences (personal fit), and work schedule satisfaction.

PubMed

Ingre, Michael; Åkerstedt, Torbjörn; Ekstedt, Mirjam; Kecklund, Göran

2012-07-01

The main objective of the present study was to investigate relative personal fit as the association between rated needs and preferences for work hours, on the one hand, and actual work hours, on the other hand, in three groups (hospital, call-center, and police) working with periodic self-rostering. We also examined the association between personal fit and satisfaction with the work schedule and preference for a fixed and regular shift schedule, respectively. We collected questionnaire data and objective work hour data over 6-12 months from the computerized self-rostering system. The response rate of the questionnaire was 69% at the hospital and call-center and 98% among the police. In total, 29 433 shifts for 285 shift workers were included in the study. Data was analyzed by means of mixed ANOVA, Kendal tau correlations and ordinal (proportional odds) logistic regression. The results show that evening types worked relatively more hours during the evening and night hours compared to morning types as an indication of relative personal fit. Relative personal fit was also found for long shift, short rest, and morning-, evening- and night-shift frequency, but only personal fit related to morning, evening and night-shift was associated with satisfaction with work hours. Reported conflicts at the workplace about work hours and problems with lack of predictability of time for family/leisure activities, was associated with poor satisfaction and a preference for a fixed shift schedule. The present study shows that periodic self-rostering is associated with relative personal fit, in particular with respect to night, evening, and morning work. Personal fit seems to be associated with satisfaction with work hours and may be a moderator of tolerance to shift work exposure.

Shift Work Disorder Among Oil Rig Workers in the North Sea

PubMed Central

Waage, Siri; Moen, Bente Elisabeth; Pallesen, Ståle; Eriksen, Hege R.; Ursin, Holger; Åkerstedt, Torbj⊘rn; Bjorvatn, Bj⊘rn

2009-01-01

Study Objectives: Shift work disorder (SWD) is a circadian rhythm sleep disorder caused by work hours during the usual sleep period. The main symptoms are excessive sleepiness and insomnia temporally associated with the working schedule. The aim of the present study was to examine SWD among shift workers in the North Sea. Design and Participants: A total of 103 shift workers (2 weeks on 7 nights/ 7days, 12-h shifts, 4 weeks off), mean age 39.8 years, working at an oil rig in the North Sea responded to a questionnaire about SWD. They also completed the Pittsburgh Sleep Quality Index, Bergen Insomnia Scale, Epworth Sleepiness Scale, Composite Morningness Questionnaire, Subjective Health Complaint Inventory, Demand/Control, and Instrumental Mastery Oriented Coping (based on the Utrecht Coping list). Most of these instruments were administered during the first day of the 2-week working period, thus reflecting symptoms and complaints during the 4-week non-work period. The shift workers were also compared to day workers at the oil rig. Results: Twenty-four individuals were classified as suffering from SWD, yielding a prevalence for SWD of 23.3%. During the 4-week non-work period, individuals with SWD reported significantly poorer sleep quality, as measured by the Pittsburgh Sleep Quality Index, and more subjective health complaints than individuals not having SWD. There were no differences between the 2 groups in sleepiness, insomnia, circadian preference, psychological demands, or control. Individuals with SWD reported significantly lower scores on coping. The reports of shift workers without SWD were similar to those of day workers regarding sleep, sleepiness, subjective health complaints, and coping. Conclusions: The prevalence of SWD was relatively high among these shift workers. Individuals with SWD reported poorer sleep quality and more subjective health complaints in the non-work period than shift workers not having SWD. Citation: Waage S; Moen BE; Pallesen S; Eriksen HR; Ursin H; Åkerstedt T; BjorvatnB. Shift work disorder among oil rig workers in the North Sea. SLEEP 2009;32(4):558-565. PMID:19413151

Exercise, Energy Balance and the Shift Worker

PubMed Central

Atkinson, Greg; Fullick, Sarah; Grindey, Charlotte; Maclaren, Don; Waterhouse, Jim

2009-01-01

Shift work is now common in society and is not restricted to heavy industry or emergency services, but is increasingly found amongst ‘white collar’ occupations and the growing number of service industries. Participation in shift work is associated with increased body mass index, prevalence of obesity and other health problems. We review the behavioural and biological disturbances that occur during shift work and discuss their impact on leisure-time physical activity and energy balance. Shift work generally decreases opportunities for physical activity and participation in sports. For those shift workers who are able to exercise, subjective and biological responses can be altered if the exercise is taken at unusual times of day and/or if the shift worker is sleep-deprived. These altered responses may in turn impact on the longer-term adherence to an exercise programme. The favourable effects of exercise on body mass control and sleep quality have not been confirmed in shift workers. Similarly, recent reports of relationships between sleep duration and obesity have not been examined in a shift work context. There is no evidence that exercise can mediate certain circadian rhythm characteristics (e.g. amplitude or timing) for improved tolerance to shift work. Total energy intake and meal composition do not seem to be affected by participation in shift work. Meal frequency is generally reduced but snacking is increased on the night shift. Unavailability of preferred foods in the workplace, a lack of time, and a reduced desire to eat at night explain these findings. ‘Normal’ eating habits with the family are also disrupted. The metabolic responses to food are also altered by shift work-mediated disruptions to sleep and circadian rhythms. Whether any interactions on human metabolism exist between timing or content of food intake and physical activity during shift work is not known at present. There are very few randomised controlled studies on the efficacy of physical activity or dietary interventions during shift work. Some favourable effects of such interventions on fatigue levels at work have been reported, but biological and behavioural outcomes relevant to long-term health and energy balance have not been studied adequately. In addition, recruitment and retention of research participants for randomised controlled trials of physical activity or dietary interventions has been very difficult. We present a model of the various behavioural and biological factors relevant to exercise and energy balance during shift work as a framework for future research. PMID:18620467

Updating the "Risk Index": A systematic review and meta-analysis of occupational injuries and work schedule characteristics.

PubMed

Fischer, Dorothee; Lombardi, David A; Folkard, Simon; Willetts, Joanna; Christiani, David C

2017-01-01

Fatigue is a major risk factor for occupational 'accidents' and injuries, and involves dimensions of physical, mental, and muscular fatigue. These dimensions are largely influenced by temporal aspects of work schedules. The "Risk Index" combines four fatigue-related components of work schedules to estimate occupational 'accident' and injury risk based on empirical trends: shift type (morning, afternoon/evening, night), length and consecutive number, and on-shift rest breaks. Since its first introduction in 2004, several additional studies have been published that allow the opportunity to improve the internal and external validity of the "Risk Index". Thus, we updated the model's estimates by systematically reviewing the literature and synthesizing study results using meta-analysis. Cochrane Collaboration directives and MOOSE guidelines were followed. We conducted systematic literature searches on each model component in Medline. An inverse variance approach to meta-analysis was used to synthesize study effect sizes and estimate between-studies variance ('heterogeneity'). Meta-regression models were conducted to explain the heterogeneity using several effect modifiers, including the sample age and sex ratio. Among 3,183 initially identified abstracts, after screening by two independent raters (95-98% agreement), 29 high-quality studies were included in the meta-analysis. The following trends were observed: Shift type. Compared to morning shifts, injury risk significantly increased on night shifts (RR = 1.36 [95%CI = 1.15-1.60], n = 14 studies), while risk was slightly elevated on afternoon/evening shifts, although non-significantly (RR = 1.12 [0.76-1.64], n = 9 studies). Meta-regressions revealed worker's age as a significant effect modifier: adolescent workers (≤ 20 y) showed a decreased risk on the afternoon/evening shift compared to both morning shifts and adult workers (p < 0.05). Number of consecutive shifts. Compared to the first shift in a block of consecutive shifts, risk increased exponentially for morning shifts (e.g., 4th: RR = 1.09 [0.90-1.32]; n = 6 studies) and night shifts (e.g., 4th: RR = 1.36 [1.14-1.62]; n = 8 studies), while risk on afternoon/evening shifts appeared unsystematic. Shift length. Injury risk rose substantially beyond the 9th hour on duty, a trend that was mirrored when looking at shift lengths (e.g., >12 h: RR = 1.34 [1.04-1.51], n = 3 studies). Rest breaks. Risk decreased for any rest break duration (e.g., 31-60 min: RR = 0.35 [0.29-0.43], n = 2 studies). With regards to time between breaks, risk increased with every additional half hour spent on the work task compared to the first 30 min (e.g., 90-119 min: RR = 1.62 [1.00-2.62], n = 3 studies). Rest break duration and interval seem to interact such that with increasing duration, the time between breaks becomes irrelevant. The updated "Risk Index". All four components were combined to form the updated model and the relative risk values estimated for a variety of work schedules. The resulting "Risk Map" shows regions of highest risk when rest breaks are not taken frequently enough (i.e. <4 h) or are too short (i.e. <30 min), when shift length exceeds 11 h, and when work takes place during the night (particularly for >3 consecutive night shifts). The "Risk Index" is proposed as an empirical model to predict occupational 'accident' and injury risk based on the most recent data in the field, and can serve as a tool to evaluate hazards and maximize safety across different work schedules.

A Comparative Study of Shift Work Effects and Injuries among Nurses Working in Rotating Night and Day Shifts in a Tertiary Care Hospital of North India.

PubMed

Verma, Anjana; Kishore, Jugal; Gusain, Shobha

2018-01-01

Shift work can have an impact on the physical and psychological well-being of the healthcare worker, affecting patients as well as their own safety at the workplace. This study was conducted to compare the health outcomes and injuries, along with associated risk factors between the nurses working in rotating night shift (RNS) as compared to day shift (DS) only. It was a cross-sectional study conducted from June to November 2016 in a tertiary care hospital of Delhi. It involved 275 nurses working in RNS and 275 nurses from DS of various departments, selected through simple random sampling. Standard Shift Work Index Questionnaire (SSI) was used as the study instrument, with selected variables (according to objectives of the study). Data were analyzed using descriptive statistics, Chi-square, t -test, and multivariate regression. Female nurses had more sleep disturbance, fatigue, and poor psychological health. Working on a contractual basis, RNS, and living outside the hospital campus were associated with higher odds of having needle stick injury (NSI). The nurses working in RNSs were found to have significantly lower mean scores in job satisfaction ( p = 0.04), sleep ( p < 0.001), and psychological well-being ( p = 0.047) as compared to DS workers. Health outcomes among nurses working in RNSs call for the interventions, focused on various factors which can be modified to provide supportive and safer working environment.

What is the impact of shift work on the psychological functioning and resilience of nurses? An integrative review.

PubMed

Tahghighi, Mozhdeh; Rees, Clare S; Brown, Janie A; Breen, Lauren J; Hegney, Desley

2017-09-01

To synthesize existing research to determine if nurses who work shifts have poorer psychological functioning and resilience than nurses who do not work shifts. Research exploring the impact of shift work on the psychological functioning and resilience of nurses is limited compared with research investigating the impact of shifts on physical outcomes. Integrative literature review. Relevant databases were searched from January 1995-August 2016 using the combination of keywords: nurse, shift work; rotating roster; night shift; resilient; hardiness; coping; well-being; burnout; mental health; occupational stress; compassion fatigue; compassion satisfaction; stress; anxiety; depression. Two authors independently performed the integrative review processes proposed by Whittemore and Knafl and a quality assessment using the mixed-methods appraisal tool by Pluye et al. A total of 37 articles were included in the review (32 quantitative, 4 qualitative and 1 mixed-methods). Approximately half of the studies directly compared nurse shift workers with non-shift workers. Findings were grouped according to the following main outcomes: (1) general psychological well-being/quality of life; (2) Job satisfaction/burnout; (3) Depression, anxiety and stress; and (4) Resilience/coping. We did not find definitive evidence that shift work is associated with poorer psychological functioning in nurses. Overall, the findings suggest that the impact of shift work on nurse psychological functioning is dependent on several contextual and individual factors. More studies are required which directly compare the psychological outcomes and resilience of nurse shift workers with non-shift workers. © 2017 John Wiley & Sons Ltd.

Shift work and overall and cause-specific mortality in the Danish nurse cohort.

PubMed

Jørgensen, Jeanette Therming; Karlsen, Sashia; Stayner, Leslie; Andersen, Johnni; Andersen, Zorana Jovanovic

2017-03-01

Objectives Evidence of an effect of shift work on all-cause and cause-specific mortality is inconsistent. This study aims to examine whether shift work is associated with increased all-cause and cause-specific mortality. Methods We linked 28 731 female nurses (age ≥44 years), recruited in 1993 or 1999 from the Danish nurse cohort where they reported information on shift work (night, evening, rotating, or day), to the Danish Register of Causes of Death to identify deaths up to 2013. We used Cox regression models with age as the underlying scale to examine the associations between night, evening, and rotating shift work (compared to day shift work) and all-cause and cause-specific mortality in models adjusted for potentially confounding variables. Results Of 18 015 nurses included in this study, 1616 died during the study time period from the following causes: cardiovascular disease (N=217), cancer (N= 945), diabetes (N=20), Alzheimer's disease or dementia (N=33), and psychiatric diseases (N=67). We found that working night [hazard ratio (HR) 1.26, 95% confidence interval 95% CI) 1.05-1.51] or evening (HR 1.29, 95% CI 1.11-1.49) shifts was associated with a significant increase in all-cause mortality when compared to working day shift. We found a significant association of night shift work with cardiovascular disease (HR 1.71, 95% CI 1.09-2.69) and diabetes (HR 12.0, 95% CI 3.17-45.2, based on 8 cases) and none with overall cancer mortality (HR 1.05, 95% CI 0.81-1.35) or mortality from psychiatric diseases (HR 1.17, 95% CI 0.47-2.92). Finally, we found strong association between evening (HR 4.28, 95% CI 1.62-11.3) and rotating (HR 5.39, 95% CI 2.35-12.3) shift work and mortality from Alzheimer's disease and dementia (based on 8 and 14 deaths among evening and rotating shift workers, respectively). Conclusions Women working night and evening shifts have increased all-cause, cardiovascular, diabetes, and Alzheimer's and dementia mortality.

The effect of split sleep schedules (6h-on/6h-off) on neurobehavioural performance, sleep and sleepiness.

PubMed

Short, Michelle A; Centofanti, Stephanie; Hilditch, Cassie; Banks, Siobhan; Lushington, Kurt; Dorrian, Jillian

2016-05-01

Shorter, more frequent rosters, such as 6h-on/6h-off split shifts, may offer promise to sleep, subjective sleepiness and performance by limiting shift length and by offering opportunities for all workers to obtain some sleep across the biological night. However, there exists a paucity of studies that have examined these shifts using objective measures of sleep and performance. The present study examined neurobehavioural performance, sleepiness and sleep during 6h-on/6h-off split sleep schedules. Sixteen healthy adults (6 males, 26.13 y ± 4.46) participated in a 9-day laboratory study that included two baseline nights (BL, 10h time in bed (TIB), 2200 h-0800 h), 4 days on one of two types of 6h-on/6h-off split sleep schedules with 5h TIB during each 'off' period (6h early: TIB 0300 h-0800 h and 1500 h-20000 h, or 6-h late: TIB 0900 h-1400 h and 2100 h-0200 h), and two recovery nights (10h TIB per night, 2200 h-0800 h). Participants received 10h TIB per 24h in total across both shift schedules. A neurobehavioural test bout was completed every 2 h during wake, which included the Psychomotor Vigilance Task (PVT) and the Karolinska Sleepiness Scale (KSS). Linear mixed effects models were used to assess the effect of day (BL, shift days 1-4), schedule (6h early, 6h late) and trial (numbers 1-6) on PVT lapses (operationalised as the number of reaction times >500 ms), PVT total lapse time, PVT fastest 10% of reaction times and KSS. Analyses were also conducted examining the effect of day and schedule on sleep variables. Overall, PVT lapses and total lapse time did not differ significantly between baseline and shift days, however, peak response speeds were significantly slower on the first shift day when compared to baseline, but only for those in the 6h-late condition. Circadian variations were apparent in performance outcomes, with individuals in the 6h-late condition demonstrated significantly more and longer lapses and slower peak reaction times at the end of their night shift (0730 h) than at any other time during their shifts. In the 6h-early condition, only response speed significantly differed across trials, with slower response speeds occurring at trial 1 (0930 h) than in trials 3 (1330 h) or 4 (2130 h). While subjective sleepiness was higher on shift days than at baseline, sleepiness did not accumulate across days. Total sleep was reduced across split sleep schedules compared to baseline. Overall, these results show that while there was not a cumulative cost to performance across days of splitting sleep, participants obtained less sleep and reported lowered alertness on shift days. Tests near the circadian nadir showed higher sleepiness and increased performance deficits. While this schedule did not produce cumulative impairment, the performance deficits witnessed during the biological night are still of operational concern for industry and workers alike. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Night-shift work increases cold pain perception.

PubMed

Pieh, Christoph; Jank, Robert; Waiß, Christoph; Pfeifer, Christian; Probst, Thomas; Lahmann, Claas; Oberndorfer, Stefan

2018-05-01

Although night-shift work (NSW) is associated with a higher risk for several physical and mental disorders, the impact of NSW on pain perception is still unclear. This study investigates the impact of NSW on cold pain perception considering the impact of mood and sleepiness. Quantitative sensory testing (QST) was performed in healthy night-shift workers. Cold pain threshold as well as tonic cold pain was assessed after one habitual night (T1), after a 12-hour NSW (T2) and after one recovery night (T3). Sleep quality was measured with the Pittsburgh Sleep Quality Index (PSQI) before T1, sleepiness with the Stanford Sleepiness Scale (SSS) and mood with a German short-version of the Profile of Mood States (ASTS) at T1, T2 and T3. Depending on the distribution of the data, ANOVAs or Friedman tests as well as t- or Wilcoxon tests were performed. Nineteen healthy shift-workers (13 females; 29.7 ± 7.5 years old; 8.1 ± 6.6 years in shift work, PSQI: 4.7 ± 2.2) were included. Tonic cold pain showed a significant difference between T1 (48.2 ± 27.5 mm), T2 (61.7 ± 26.6 mm; effect size: Cohen's d=.49; percent change 28%), and T3 (52.1 ± 28.7 mm) on a 0-100 mm Visual Analog Scale (p = 0.007). Cold pain threshold changed from 11.0 ± 7.9 °C (T1) to 14.5 ± 8.8 °C (T2) (p = 0.04), however, an ANOVA comparing T1, T2, and T3 was not significant (p = 0.095). Sleepiness (SSS) and mood (ASTS) changed significantly between T1, T2 and T3 (p-values < 0.01). The change of mood but not of sleepiness correlated with the difference in tonic cold pain from T1 to T2 (R: 0.53; R 2 : 0.29; p = 0.022). NSW increases cold pain perception. The same tonic cold pain stimulus is rated 28% more painful after NSW and normalizes after a recovery night. Increases in cold pain perception due to NSW appear to be more strongly related to changes in mood as compared to changes in sleepiness. Copyright © 2018 Elsevier B.V. All rights reserved.

Compensation for unfavorable characteristics of irregular individual shift rotas.

PubMed

Knauth, Peter; Jung, Detlev; Bopp, Winfried; Gauderer, Patric C; Gissel, Andreas

2006-01-01

Some employees of TV companies, such as those who produce remote TV programs, have to cope with very irregular rotas and many short-term schedule deviations. Many of these employees complain about the negative effects of such on their wellbeing and private life. Therefore, a working group of employers, council representatives, and researchers developed a so-called bonus system. Based on the criteria of the BESIAK system, the following list of criteria for the ergonomic assessment of irregular shift systems was developed: proportion of night hours worked between 22 : 00 and 01 : 00 h and between 06 : 00 and 07 : 00 h, proportion of night hours worked between 01 : 00 and 06 : 00 h, number of successive night shifts, number of successive working days, number of shifts longer than 9 h, proportion of phase advances, off hours on weekends, work hours between 17 : 00 and 23 : 00 h from Monday to Friday, number of working days with leisure time at remote places, and sudden deviations from the planned shift rota. Each individual rota was evaluated in retrospect. If pre-defined thresholds of criteria were surpassed, bonus points were added to the worker's account. In general, more bonus points add up to more free time. Only in particular cases was monetary compensation possible for some criteria. The bonus point system, which was implemented in the year 2002 for about 850 employees of the TV company, has the advantages of more transparency concerning the unfavorable characteristics of working-time arrangements, incentive for superiors to design "good" rosters that avoid the bonus point thresholds (to reduce costs), positive short-term effects on the employee social life, and expected positive long-term effects on the employee health. In general, the most promising approach to cope with the problems of shift workers in irregular and flexible shift systems seems to be to increase their influence on the arrangement of working times. If this is not possible, bonus point systems may help to achieve greater transparency and fairness in the distribution of unfavorable working-time arrangements within a team, and even reduce the unnecessary unfavorable aspects of shift systems.

Nutritional status and eating habits of bus drivers during the day and night.

PubMed

Balieiro, Laura Cristina Tibiletti; Rossato, Luana Thomazetto; Waterhouse, Jim; Paim, Samantha Lemos; Mota, Maria Carliana; Crispim, Cibele Aparecida

2014-12-01

The aim of this study was to compare anthropometry and food intake patterns in bus drivers working during the day and night. One hundred and fifty males (81 night workers and 69 day workers) participated in the study. Dietary intake was assessed using a validated semi-quantitative food frequency questionnaire. Measurements of height, weight, waist circumference (WC), systolic and diastolic blood pressure, blood glucose, and lipid profile were obtained. A significant difference between groups was observed for mean WC (98.5 ± 10.7 cm in day workers versus 103.2 ± 9.7 cm in night workers; p = 0.005). Night workers had higher prevalence of being overweight and obese (BMI ≥ 25 kg/m(2)) than day workers (78.2% day workers versus 90.2% night workers; p = 0.004) and increased WC (>94 cm) (72.4% day workers versus 86.4% night workers; p = 0.03). Significant differences were found for meat consumption (2.3 servings ±0.9 for night workers versus 2.0 servings ±0.7 day workers, p = 0.04) and fruit intake (0.9 servings ±0.4 for night workers versus 0.7 servings for day workers ±0.5; p = 0.006). Night workers had a lower intake of vegetables than recommended compared to day workers (100 versus 92.7%, respectively, p = 0.01) and higher intake of oil (40.7 versus 24.6%, p = 0.03). Multivariate logistic regression analysis indicated that night work was associated with being overweight (OR = 2.94, 95% IC: 1.14-7.66, p = 0.03) and abnormal values of WC (OR = 2.82, 95% IC: 1.20-6.69, p = 0.009) after adjusting for potential confounders. It is concluded that night workers had a higher prevalence and risk of being overweight/obese and increased WC compared with day workers. Night workers also presented a higher proportion of inappropriate intakes of food groups when compared to day workers, even though both groups were eating poor diets. These results demonstrate the need of lifestyle-intervention programs in these workers.

Raising awareness of psychosocial factors in the occurrence of low back symptoms in developing countries.

PubMed

Widanarko, Baiduri; Legg, Stephen; Devereux, Jason; Stevenson, Mark

2012-01-01

Although there is strong evidence that single physical, psychosocial and organisational risk factors are each independent predictors of low back symptoms (LBS), little is known about their combination/interaction, particularly in those working in developing countries. A total of 1294 Indonesian coal mining industry workers reported information about physical, psychosocial, and organisational factors using self-reported questionnaires and were placed into one of four combination exposure groups: 1) high physical (working with bent trunk; whole body vibration exposure; lifting) and high psychosocial (high effort; low reward; work stress), 2) high physical and low psychosocial, 3) low physical and high psychosocial, and 4) low physical and low psychosocial (as the reference group). The odds of LBS in the high physical and high psychosocial group was 5.15 times (95% confidence interval 2.69-9.86) that of the reference group. Psychosocial factors played a more important role than physical factors in increasing the likelihood of reporting LBS. Permanent and night shift workers were more likely to report LBS. These findings imply that efforts to reduce LBS in this workplace should address both psychosocial and physical factors but psychosocial factors should be the priority, with a special focus on permanent and night shift workers.

Influence of shift work on early reproductive outcomes: a systematic review and meta-analysis.

PubMed

Stocker, Linden J; Macklon, Nicholas S; Cheong, Ying C; Bewley, Susan J

2014-07-01

To determine whether an association exists between shift work and early reproductive outcomes. MEDLINE, Embase, and Web of Science were searched. Additional sources included Google Scholar, the Cochrane Library, online publications of national colleges, the ClinicalTrials.gov, and references of retrieved papers. Included studies compared female shift workers (work outside 8:00 AM to 6:00 PM) with nonshift workers with menstrual disruption (cycles less than 25 days or greater than 31 days), infertility (time-to-pregnancy exceeding 12 months), or early spontaneous pregnancy loss (less than 25 weeks). Two reviewers extracted adjusted and raw data. Random effect models were used to pool data weighting for the inverse of variance. Assessments of heterogeneity, bias, and subgroup analyses were performed. Sixteen independent cohorts from 15 studies (123,403 women) were subject to analysis. Shift workers had increased rates of menstrual disruption (16.05% [2,207/13,749] compared with 13.05% [7,561/57,932] [n=71.681, odds ratio {OR} 1.22, 95% confidence interval {CI} 1.15-1.29, I 0%]) and infertility (11.3% [529/4,668] compared with 9.9% [2,354/23,811] [OR 1.80, 95% CI 1.01-3.20, I 94%]) but not early spontaneous pregnancy loss (11.84% [939/7,931] compared with 12.11% [1,898/15,673] [n=23,604, OR 0.96, 95% CI 0.88-1.05, I 0%]). Night shifts were associated with increased early spontaneous pregnancy loss (n=13,018, OR 1.29, 95% CI 1.11-1.50, I 0%). Confounder adjustment led to persistent relationships between shift work and menstrual disruption (adjusted OR 1.15, 95% CI 1.01-1.31, I 70%) but not infertility (adjusted OR 1.11 95% CI 0.86-1.44, I 61%). The association between night shifts and early spontaneous pregnancy loss remained (adjusted OR 1.41 95% CI 1.22-1.63, I 0%). This review provides evidence for an association between performing shift work and early reproductive outcomes, consistent with later pregnancy findings. However, there is currently insufficient evidence for clinicians to advise restricting shift work in women of reproductive age.

[Working time and sleep in nursing staff employed in "3 x 8" and "2 x 12" fast rotating shift schedules].

PubMed

Castellini, G; Anelli, M M; Punzi, S; Boari, P; Camerino, D; Costa, G

2011-01-01

The study is aimed at assessing, in 200 nurses shift workers, the impact on sleep of two different working areas ("emergency" and "hospitalization") having the same "3 x 8" shift system, and of two different shift schedules at quick rotation ("2 x 12" and "3 x 8") in the same working area ("emergency"). Night and morning shifts prove to interfere to a greater extent with sleep in relation to both "2 x 12" and "3 x 8" shift systems as well as to the two operative areas. Hence the importance to consider in shift work planning, the direction of shift rotation and the length of the duty period according to the type of activity.

[Stress and work-related injuries].

PubMed

Tomei, G; Capozzella, A; Rosati, M V; Tomei, F; Rinaldi, G; Chighine, A; di Marzio, A; Sacco, C; Pimpinella, B; Suppi, A; Scala, B; Casale, T; Sancini, A

2015-01-01

The aim of this study was to evaluate in scientific literature the more frequent work injuries among the occupational categories examined (construction workers, healthcare workers, night workers and shift work, drivers) and to identify occupational stressors that increase the risk of injury. The research was conducted through review of the scientific literature between 1990 and 2014. Two hundred articles were found of which 42 selected in the following categories: construction workers, healthcare workers, shift workers, lorry drivers. The movement of machinery and working at height are due to injury for building sector and they were positively correlated with physical (r = 0,206) and mental (r = 0,254) stress. In health workers the injuries are more frequently bruises and sprains (50%). Studies showed a higher rate of injury in a group of shift workers compared to a control group on a rota basis (p <0.0001). Road accidents for drivers represent the most frequent cause of injury of which 13% comes from falling asleep, while 31% from distractions (OR = 3.16; CI = 1:22 to 8:24). Nurses have frequent injuries due to bruises, lumbago, punctures with needles and surgical wounds. Construction workers often suffer serious injury derived from falls at height, handling machinery. For workers on a rota basis, injuries are often related to lack of sleep. Road accidents in drivers are the most common injuries. A synergistic action finalized to promote health and safety organization, to ensure a work environment more secure, is advisable.

Nursing work hours: individual needs versus working conditions.

PubMed

Silva, Amanda Aparecida; Rotenberg, Lúcia; Fischer, Frida Marina

2011-12-01

To assess factors associated with professional and total hours of work (work + home) among nursing staff. Cross-sectional study conducted in a university hospital in the city of São Paulo, southeastern Brazil, between 2004 and 2005. A total of 696 workers (nurses, nurse technicians and aids), mostly women (87.8%) working day and/or night shifts, participated in the study. A self-administered questionnaire was used to collected information on demographic characteristics, and working and life conditions. Translated and adapted into Portuguese versions of the Job Stress Scale, Effort-reward imbalance, Short-Form-Health-related quality of life and the Work Ability Index were also administered. Logistic regression models were used for data analysis. Sole breadwinner, working night shifts and effort-reward imbalance were the variables associated with both professional (OR = 3.38, OR = 10.43, OR = 2.07, respectively) and total hours of work (OR = 1.57, OR = 3.37, OR = 2.75, respectively). There was no significant association between the variables related to hours of work and low Work Ability Index. Inadequate rest at home was statistically associated with professional (OR = 2.47) and total hours of work (OR = 1.48). Inadequate leisure time was significantly associated with professional hours of work (OR = 1.58) and barely associated with total hours of work (OR = 1.43). The sole breadwinner, working night shifts and effort-reward imbalance are variables that need to be further investigated in studies on work hours among nursing staff. These studies should explore workers' income and the relationship between effort and reward, taking into consideration gender issues.

Adaptation rate of 6-sulfatoxymelatonin and cognitive performance in offshore fleet shift workers: a field study.

PubMed

Hansen, Jakob H; Geving, Ingunn H; Reinertsen, Randi E

2010-08-01

To determine the total phase delay and adaptation rate of 6-sulfatoxymelatonin (aMT6s) on subjective and objective sleep quality and cognitive performance after 7 days of working night shifts (1800-0600 hours). The subjects studied were offshore fleet workers (N = 7). Seven days of urine samples were collected to determine the total phase delay and adaptation rate of aMT6s. Subjective and objective sleep quality was registered with sleep diaries and actigraphy on a daily basis. Cognitive performance, as measured by vigilance and reaction time, was measured with the Vienna test system on days 1 and 7. Light exposure was measured in the vessel compartments daily. The rhythm of aMT6s shifted significantly from 4.78 +/- 0.94 h on day 1 to 8.84 +/- 1.76 h on day 7. Rate of adaptation was 0.84 h per day. Subjective sleep quality showed significant time effects on four variables, but objective sleep quality did not show any significant time effects. Vigilance and reaction time improved significantly from days 1 to 7. Light exposure intensities varied between 3 and 243 lux. This field study showed that offshore fleet workers are able to adapt to the imposed regimen of 12-h night shifts. The adaptation is slower compared to other branches of the offshore industry, which most likely is due to lower light exposure. Subjective sleep quality improved to some extent, but the results were not conclusive. No significant effects were observed in the objective measures. Cognitive performance improved significantly, which was likely to be caused by the extended working hours on day 1 and an entrainment of the suprachiasmatic nuclei (SCN).

5 CFR 532.505 - Night shift differentials.

Code of Federal Regulations, 2010 CFR

2010-01-01

... employee regularly assigned to a night shift who is temporarily assigned to a day shift or to a night shift... regularly assigned to a day shift who is temporarily assigned to a night shift shall be paid a night shift... schedule involving work on both day and night shifts shall be paid a night shift differential only for any...

Progressive decrease of melatonin production over consecutive days of simulated night work.

PubMed

Dumont, Marie; Paquet, Jean

2014-12-01

Decreased melatonin production, due to nighttime exposure to light, has been proposed as one of the physiological mechanisms increasing cancer risk in night workers. However, few studies measured melatonin production in night workers, and most of these studies did not measure melatonin over 24 h. One study compared total melatonin production between day and night shifts in rotating night workers and did not find significant differences. However, without baseline measures, it was not possible to exclude that melatonin production was reduced during both day and night work. Here, we used data collected in a simulation study of night work to determine the effect of night work on both nighttime and 24-h melatonin production, during three consecutive days of simulated night work. Thirty-eight healthy subjects (15 men, 23 women; 26.6 ± 4.2 years) participated in a 6-d laboratory study. Circadian phase assessments were made with salivary dim light melatonin onset (DLMO) on the first and last days. Simulated day work (09:00-17:00 h) occurred on the second day, followed by three consecutive days of simulated night work (00:00-08:00 h). Light intensity at eye level was set at 50 lux during both simulated day and night work. The subjects were divided into three matched groups exposed to specific daytime light profiles that produced various degrees of circadian phase delays and phase advances. Melatonin production was estimated with the excretion of urinary 6-sulfatoxymelatonin (aMT6s). For the entire protocol, urine was collected every 2 h, except for the sleep episodes when the interval was 8 h. The aMT6s concentration in each sample was multiplied by the urine volume and then added to obtain total aMT6s excretion during nighttime (00:00-08:00 h) and during each 24-h day (00:00-00:00 h). The results showed that melatonin production progressively decreased over consecutive days of simulated night work, both during nighttime and over the 24 h. This decrease was larger in women using oral contraceptives. There was no difference between the three groups, and the magnitude of the decrease in melatonin production for nighttime and for the 24 h was not associated with the magnitude of the absolute circadian phase shift. As light intensity was relatively low and because the decrease in melatonin production was progressive, direct suppression by nighttime light exposure was probably not a significant factor. However, according to previous experimental observations, the decrease in melatonin production most likely reflects the circadian disruption associated with the process of re-entrainment. It remains to be determined whether reduced melatonin production can be harmful by itself, but long-term and repeated circadian disruption most probably is.

Rotating Night Shift Work and Risk of Type 2 Diabetes: Two Prospective Cohort Studies in Women

PubMed Central

Pan, An; Schernhammer, Eva S.; Sun, Qi; Hu, Frank B.

2011-01-01

Background Rotating night shift work disrupts circadian rhythms and has been associated with obesity, metabolic syndrome, and glucose dysregulation. However, its association with type 2 diabetes remains unclear. Therefore, we aimed to evaluate this association in two cohorts of US women. Methods and Findings We followed 69,269 women aged 42–67 in Nurses' Health Study I (NHS I, 1988–2008), and 107,915 women aged 25–42 in NHS II (1989–2007) without diabetes, cardiovascular disease, and cancer at baseline. Participants were asked how long they had worked rotating night shifts (defined as at least three nights/month in addition to days and evenings in that month) at baseline. This information was updated every 2–4 years in NHS II. Self-reported type 2 diabetes was confirmed by a validated supplementary questionnaire. We documented 6,165 (NHS I) and 3,961 (NHS II) incident type 2 diabetes cases during the 18–20 years of follow-up. In the Cox proportional models adjusted for diabetes risk factors, duration of shift work was monotonically associated with an increased risk of type 2 diabetes in both cohorts. Compared with women who reported no shift work, the pooled hazard ratios (95% confidence intervals) for participants with 1–2, 3–9, 10–19, and ≥20 years of shift work were 1.05 (1.00–1.11), 1.20 (1.14–1.26), 1.40 (1.30–1.51), and 1.58 (1.43–1.74, p-value for trend <0.001), respectively. Further adjustment for updated body mass index attenuated the association, and the pooled hazard ratios were 1.03 (0.98–1.08), 1.06 (1.01–1.11), 1.10 (1.02–1.18), and 1.24 (1.13–1.37, p-value for trend <0.001). Conclusions Our results suggest that an extended period of rotating night shift work is associated with a modestly increased risk of type 2 diabetes in women, which appears to be partly mediated through body weight. Proper screening and intervention strategies in rotating night shift workers are needed for prevention of diabetes. Please see later in the article for the Editors' Summary PMID:22162955

Alertness, performance and off-duty sleep on 8-hour and 12-hour night shifts in a simulated continuous operations control room setting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, T.L.

A growing number of nuclear power plants in the United States have adopted routine 12-hr shift schedules. Because of the potential impact that extended work shifts could have on safe and efficient power plant operation, the U.S. Nuclear Regulatory Commission funded research on 8-hr and 12-hr shifts at the Human Alertness Research Center (HARC) in Boston, Massachusetts. This report describes the research undertaken: a study of simulated 8-hr and 12-hr work shifts that compares alertness, speed, and accuracy at responding to simulator alarms, and relative cognitive performance, self-rated mood and vigor, and sleep-wake patterns of 8-hr versus 12-hr shift workers.

A work-life perspective on sleep and fatigue--looking beyond shift workers.

PubMed

Skinner, Natalie; Dorrian, Jill

2015-01-01

This study examines sleep and fatigue through a work-life lens. Whilst most often thought of as an issue for shift workers, this study observed that self-reported insufficient sleep and fatigue were prevalent for workers on standard daytime schedules. Using a representative sample of 573 daytime workers (51.3% men; 70.7% aged 25-54 yr) from one Australian state, it was observed that 26.4% of daytime workers never or rarely get the seven hours of sleep a night that is recommended for good health. Those with parenting responsibilites (29.4%) or working long (45+) hours (37.4%) were most likely to report insufficient sleep. Whereas mothers in full-time work were most likely to report frequent fatigue (42.5%). This study highlights the common experience of insufficient sleep and fatigue in a daytime workforce, with significant implications for health and safety at work and outside of work. Stronger and more effective legislation addressing safe and 'decent' working time is clearly needed, along with greater awareness and acceptance within workplace cultures of the need to support reasonable workloads and working hours.

Influence of the Circadian System on Disease Severity

PubMed Central

Litinski, Mikhail; Scheer, Frank AJL; Shea, Steven A

2009-01-01

Synopsis The severity of many diseases varies across the day and night. For example, adverse cardiovascular incidents peak in the morning, asthma is often worse at night and temporal lobe epileptic seizures are most prevalent in the afternoon. These patterns may be due to the day/night rhythm in environment and behavior, and/or endogenous circadian rhythms in physiology. Furthermore, chronic misalignment between the endogenous circadian timing system and the behavioral cycles could be a cause of increased risk of diabetes, obesity, cardiovascular disease and certain cancers in shift workers. Here we describe the magnitude, relevance and potential biological basis of such daily changes in disease severity and of circadian/behavioral misalignment, and present how these insights may help in the development of appropriate chronotherapy. PMID:20161149

Detection of the Sleep Stages Throughout Non-Obtrusive Measures of Inter-Beat Fluctuations and Motion: Night and Day Sleep of Female Shift Workers

NASA Astrophysics Data System (ADS)

Mendez, Martin O.; Palacios-Hernandez, Elvia R.; Alba, Alfonso; Kortelainen, Juha M.; Tenhunen, Mirja L.; Bianchi, Anna M.

Automatic sleep staging based on inter-beat fluctuations and motion signals recorded through a pressure bed sensor during sleep is presented. The analysis of the sleep was based on the three major divisions of the sleep time: Wake, non-rapid eye movement (nREM) and rapid eye movement (REM) sleep stages. Twelve sleep recordings, from six females working alternate shift, with their respective annotations were used in the study. Six recordings were acquired during the night and six during the day after a night shift. A Time-Variant Autoregressive Model was used to extract features from inter-beat fluctuations which later were fed to a Support Vector Machine classifier. Accuracy, Kappa index, and percentage in wake, REM and nREM were used as performance measures. Comparison between the automatic sleep staging detection and the standard clinical annotations, shows mean values of 87% for accuracy 0.58 for kappa index, and mean errors of 5% for sleep stages. The performance measures were similar for night and day sleep recordings. In this sample of recordings, the results suggest that inter-beat fluctuations and motions acquired in non-obtrusive way carried valuable information related to the sleep macrostructure and could be used to support to the experts in extensive evaluation and monitoring of sleep.

Factors associated with severe occupational injuries at mining company in Zimbabwe, 2010: a cross-sectional study.

PubMed

Chimamise, Chipo; Gombe, Notion Tafara; Tshimanga, Mufuta; Chadambuka, Addmore; Shambira, Gerald; Chimusoro, Anderson

2013-01-01

Injury rate among mining workers in Zimbabwe was 789/1000 workers in 2008. The proportion of severe occupational injuries increased from 18% in 2008 to 37% in 2009. We investigated factors associated with severe injuries at the mine. An unmatched 1:1 case-control study was carried out at the mine, a case was any worker who suffered severe occupational injury at the mine and was treated at the mine or district hospital from January 2008 to April 2010, a control was any worker who did not suffer occupational injury during same period. We randomly selected 156 cases and 156 controls and used interviewer administered questionnaires to collect data from participants. Majority of cases, 155(99.4%) and of controls 142(91%) were male, 127(81.4%) of cases and 48(30.8%) of controls worked underground. Majority (73.1%) of severe occupational injuries occurred during night shift. Underground temperatures reached 500C. Factors independently associated with getting severe occupational injuries included working underground (AOR=10.55; CI 5.97-18.65), having targets per shift (AOR=12.60; CI 3.46-45.84), inadequate PPE (AOR=3.65 CI 1.34-9.89) and working more than 8 hours per shift (AOR=8.65 CI 2.99-25.02). Having targets exerts pressure to perform on workers. Prolonged working periods decrease workers' attention and concentration resulting in increased risk to severe injuries as workers become exhausted, lose focus and alertness. Underground work environment had environmental hazards so managers to install adequate ventilation and provide adequate PPE. Management agreed to standardize shifts to eight hours and workers in some departments have been supplied with adequate PPE.

Shift work and colorectal cancer risk in the MCC-Spain case-control study.

PubMed

Papantoniou, Kyriaki; Castaño-Vinyals, Gemma; Espinosa, Ana; Turner, Michelle C; Alonso-Aguado, Maria Henar; Martin, Vicente; Aragonés, Nuria; Pérez-Gómez, Beatriz; Pozo, Benito Mirón; Gómez-Acebo, Inés; Ardanaz, Eva; Altzibar, Jone M; Peiro, Rosana; Tardon, Adonina; Lorca, José Andrés; Chirlaque, Maria Dolores; García-Palomo, Andrés; Jimenez-Moleon, Jose Juan; Ierssen, Trinidad; Ederra, Maria; Amiano, Pilar; Pollan, Marina; Moreno, Victor; Kogevinas, Manolis

2017-05-01

Objectives Shift work that involves circadian disruption has been associated with a higher cancer risk. Most epidemiological studies to date have focused on breast cancer risk and evidence for other common tumors is limited. We evaluated the risk for colorectal cancer (CRC) in relation to shift work history in a population-based case-control study in Spain. Methods This analysis included 1626 incident CRC cases and 3378 randomly selected population controls of both sexes, enrolled in 11 regions of Spain. Sociodemographic and lifestyle information was assessed in face-to-face interviews. Shift work was assessed in detail throughout lifetime occupational history. We estimated the risk of colon and rectal cancer associated with rotating and permanent shift work (ever, cumulative duration, age of first exposure) using unconditional logistic regression analysis adjusting for potential confounders. Results Having ever performed rotating shift work (morning, evening and/or night) was associated with an increased risk for CRC [odds ratio (OR) 1.22, 95% confidence interval (95% CI) 1.04-1.43], as compared to day workers. Having ever worked permanent night shifts (≥3 nights/month) was not associated with CRC risk (OR 0.79, 95% CI 0.62-1.00). OR increased with increasing lifetime cumulative duration of rotating shift work (P-value for trend 0.005) and were highest among subjects in the top quartiles of exposure (3 rd quartile, 20-34 years, OR 1.38, 95%CI 1.06-1.81; 4 th quartile, ≥35 years, OR 1.36, 95% CI 1.02-1.79). Conclusions These data suggest that rotating shift work may increase the risk of CRC especially after long-term exposures.

Concepts in human biological rhythms

PubMed Central

Reinberg, Alain; Ashkenazi, Israel

2003-01-01

Biological rhythms and their temporal organization are adaptive phenomena to periodic changes in environmental factors linked to the earth's rotation on its axis and around the sun. Experimental data from the plant and animal kingdoms have led to many models and concepts related to biological clocks that help describe and understand the mechanisms of these changes. Many of the prevailing concepts apply to all organisms, but most of the experimental data are insufficient to explain the dynamics of human biological clocks. This review presents phenomena thai are mainly characteristic ofand unique to - human chronobiology, and which cannot be fully explained by concepts and models drawn from laboratory experiments. We deal with the functional advantages of the human temporal organization and the problem of desynchronization, with special reference to the period (τ) of the circadian rhythm and its interindividual and intraindividual variability. We describe the differences between right- and left-hand rhythms suggesting the existence of different biological clocks in the right and left cortices, Desynchronization of rhythms is rather frequent (one example is night shift workers). In some individuals, desynchronization causes no clinical symptoms and we propose the concept of “allochronism” to designate a variant of the human temporal organization with no pathological implications. We restrict the term “dyschronism” to changes or alterations in temporal organization associated with a set of symptoms similar to those observed in subjects intolerant to shift work, eg, persisting fatigue and mood and sleep alterations. Many diseases involve chronic deprivation of sleep at night and constitute conditions mimicking thai of night shift workers who are intolerant to desynchronization. We also present a genetic model (the dian-circadian model) to explain interindividual differences in the period of biological rhythms in certain conditions. PMID:22033796

Twenty-four/seven: a mixed-method systematic review of the off-shift literature

PubMed Central

de Cordova, Pamela B.; Phibbs, Ciaran S.; Bartel, Ann P.; Stone, Patricia W.

2012-01-01

Aim This article is a report of a review that aimed to synthesize qualitative and quantitative evidence of ‘off-shifts’ (nights, weekends and/or holidays) on quality and employee outcomes in hospitals. Background Healthcare workers provide 24-hour-a-day, 7-day-a-week service. Quality and employee outcomes may differ on off-shifts as compared to regular hours. Data sources Searches for studies occurred between the years 1985–2011 using computerized databases including Business Source Complete, EconLit, ProQuest, PubMed and MEDLINE. Review design and methods Design was a mixed-method systematic review with quantitative and qualitative studies. To be included, studies met the following criteria: (1) the independent variable was an off-shift; (2) the article was a research study and peer-reviewed; (3) the article could be obtained in English; and (4) the article pertained to health care. Studies were not excluded on design. Results Sixty studies were included. There were 37 quality outcome, 19 employee outcome and four qualitative studies. In the quality outcome studies, researchers often used quantitative, longitudinal study designs with large sample sizes. Researchers found important differences between patients admitted on weekends and mortality. Important differences were also found between nighttime birth and mortality and rotating night work and fatigue, stress and low mental well-being. Most studies (9 of 12) did not find an important association between patients admitted at night and mortality. Conclusion Patient outcomes on weekends and employee outcomes at night are worse than during the day. It is important to further investigate why care on off-shifts differs from weekly day shifts. PMID:22905343

Correlates to sleepiness on night shift among male workers engaged in three-shift work in a chemical plant: its association with sleep practice and job stress.

PubMed

Kageyama, Takayuki; Kobayashi, Toshio; Abe-Gotoh, Ayano

2011-01-01

The purpose of this study was to examine the correlation of sleepiness during night shift (SNS) in male shiftworkers with nonpharmacological self-management (nPSM) practices to facilitate good day sleep, and also with job stress. Sleepiness on the job and possible correlates to SNS among 157 male shiftworkers in a rotating three-shift schedule at a chemical plant were cross-sectionally investigated using a self-administered questionnaire. Multivariate analyses revealed that SNS was positively associated with drinking alcoholic beverages before day sleep, but inversely associated with subjective health status, being of the evening type, abstaining from caffeine before day sleep, having a bath before day sleep, job control, reward from work, feeling suited to the job, and support from colleagues. SNS correlated with certain nPSM practices and also with possible modifiers of job stress. These findings provide clues to developing countermeasures against SNS among shiftworkers. The effects of nPSM practices and job stress management on their day sleep and SNS should be examined in detail.

Pattern extraction for high-risk accidents in the construction industry: a data-mining approach.

PubMed

Amiri, Mehran; Ardeshir, Abdollah; Fazel Zarandi, Mohammad Hossein; Soltanaghaei, Elahe

2016-09-01

Accidents involving falls and falling objects (group I) are highly frequent accidents in the construction industry. While being hit by a vehicle, electric shock, collapse in the excavation and fire or explosion accidents (group II) are much less frequent, they make up a considerable proportion of severe accidents. In this study, multiple-correspondence analysis, decision tree, ensembles of decision tree and association rules methods are employed to analyse a database of construction accidents throughout Iran between 2007 and 2011. The findings indicate that in group I, there is a significant correspondence among these variables: time of accident, place of accident, body part affected, final consequence of accident and lost workdays. Moreover, the frequency of accidents in the night shift is less than others, and the frequency of injury to the head, back, spine and limbs are more. In group II, the variables time of accident and body part affected are mostly related and the frequency of accidents among married and older workers is more than single and young workers. There was a higher frequency in the evening, night shifts and weekends. The results of this study are totally in line with the previous research.

How do different definitions of night shift affect the exposure assessment of night work?

PubMed

Garde, Anne Helene; Hansen, Johnni; Kolstad, Henrik A; Larsen, Ann Dyreborg; Hansen, Åse Marie

The aim is to show how different definitions affect the proportion of shifts classified as night shifts. The Danish Working Hour Database was used to calculate number of night shifts according to eight definitions. More than 98% of the total night shifts were night shifts by use of both the reference definition (at least 3 h of work between 24:00 and 05:00) and definitions using a period during the night. The overlap with definitions based on starting and ending time was less pronounced (64-71 %). The proportion of classified night shifts differs little when night shifts are based on definitions including a period during the night. Studies based on other definitions may be less comparable.

Short rest between shift intervals increases the risk of sick leave: a prospective registry study.

PubMed

Vedaa, Øystein; Pallesen, Ståle; Waage, Siri; Bjorvatn, Bjørn; Sivertsen, Børge; Erevik, Eilin; Svensen, Erling; Harris, Anette

2017-07-01

The purpose of this study was to use objective registry data to prospectively investigate the effects of quick returns (QR, <11 hours of rest between shifts) and night shifts on sick leave. A total of 1538 nurses (response rate =41.5%) answered questionnaires on demographics and personality and provided consent to link this information to registry data on shift work and sick leave from employers' records. A multilevel negative binomial model was used to investigate the predictive effect of exposure to night shifts and QR every month for 1 year, on sick leave the following month. Exposure to QR the previous month increased the risk for sick leave days (incidence rate ratio (IRR)=1.066, 95% CI 1.022 to 1.108, p<0.01) and sick leave spells (IRR=1.059, 95% CI 1.025 to 1.097, p<0.001) the following month, whereas night shifts did not. 83% per cent of the nurses experienced QR within a year, and on average they were exposed to 3.0 QR per month (SD=1.6). Personality characteristics associated with shift work tolerance (low on morningness, low on languidity and high on flexibility) were not associated with sick leave, and did not moderate the relationship between QR and sick leave. We found a positive linear relationship between QR and sick leave. Avoiding QR may help reduce workers' sick leave. The restricted recovery opportunity associated with QR may give little room for beneficial effects of individual characteristics usually associated with shift work tolerance. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Factors associated with severe occupational injuries at mining company in Zimbabwe, 2010: a cross-sectional study

PubMed Central

Chimamise, Chipo; Gombe, Notion Tafara; Tshimanga, Mufuta; Chadambuka, Addmore; Shambira, Gerald; Chimusoro, Anderson

2013-01-01

Introduction Injury rate among mining workers in Zimbabwe was 789/1000 workers in 2008. The proportion of severe occupational injuries increased from 18% in 2008 to 37% in 2009. We investigated factors associated with severe injuries at the mine. Methods An unmatched 1:1 case-control study was carried out at the mine, a case was any worker who suffered severe occupational injury at the mine and was treated at the mine or district hospital from January 2008 to April 2010, a control was any worker who did not suffer occupational injury during same period. We randomly selected 156 cases and 156 controls and used interviewer administered questionnaires to collect data from participants. Results Majority of cases, 155(99.4%) and of controls 142(91%) were male, 127(81.4%) of cases and 48(30.8%) of controls worked underground. Majority (73.1%) of severe occupational injuries occurred during night shift. Underground temperatures reached 500C. Factors independently associated with getting severe occupational injuries included working underground (AOR = 10.55; CI 5.97-18.65), having targets per shift (AOR = 12.60; CI 3.46-45.84), inadequate PPE (AOR= 3.65 CI 1.34-9.89) and working more than 8 hours per shift (AOR = 8.65 CI 2.99-25.02). Conclusion Having targets exerts pressure to perform on workers. Prolonged working periods decrease workers’ attention and concentration resulting in increased risk to severe injuries as workers become exhausted, lose focus and alertness. Underground work environment had environmental hazards so managers to install adequate ventilation and provide adequate PPE. Management agreed to standardize shifts to eight hours and workers in some departments have been supplied with adequate PPE. PMID:23504270

Sleep inertia associated with a 10-min nap before the commute home following a night shift: A laboratory simulation study.

PubMed

Hilditch, Cassie J; Dorrian, Jillian; Centofanti, Stephanie A; Van Dongen, Hans P; Banks, Siobhan

2017-02-01

Night shift workers are at risk of road accidents due to sleepiness on the commute home. A brief nap at the end of the night shift, before the commute, may serve as a sleepiness countermeasure. However, there is potential for sleep inertia, i.e. transient impairment immediately after awakening from the nap. We investigated whether sleep inertia diminishes the effectiveness of napping as a sleepiness countermeasure before a simulated commute after a simulated night shift. N=21 healthy subjects (aged 21-35 y; 12 females) participated in a 3-day laboratory study. After a baseline night, subjects were kept awake for 27h for a simulated night shift. They were randomised to either receive a 10-min nap ending at 04:00 plus a 10-min pre-drive nap ending at 07:10 (10-NAP) or total sleep deprivation (NO-NAP). A 40-min York highway driving task was performed at 07:15 to simulate the commute. A 3-min psychomotor vigilance test (PVT-B) and the Samn-Perelli Fatigue Scale (SP-Fatigue) were administered at 06:30 (pre-nap), 07:12 (post-nap), and 07:55 (post-drive). In the 10-NAP condition, total pre-drive nap sleep time was 9.1±1.2min (mean±SD), with 1.3±1.9min spent in slow wave sleep, as determined polysomnographically. There was no difference between conditions in PVT-B performance at 06:30 (before the nap). In the 10-NAP condition, PVT-B performance was worse after the nap (07:12) compared to before the nap (06:30); no change across time was found in the NO-NAP condition. There was no significant difference between conditions in PVT-B performance after the drive. SP-Fatigue and driving performance did not differ significantly between conditions. In conclusion, the pre-drive nap showed objective, but not subjective, evidence of sleep inertia immediately after awakening. The 10-min nap did not affect driving performance during the simulated commute home, and was not effective as a sleepiness countermeasure. Copyright © 2015 Elsevier Ltd. All rights reserved.

Light pollution, reproductive function and cancer risk.

PubMed

Anisimov, Vladimir N

2006-01-01

At present, light pollution (exposure to light-at-night) both in the form of occupational exposure during night work and as a personal choice and life style, is experienced by numerous night-active members of our society. Disruption of the circadian rhythms induced by light pollution has been associated with cancer in humans. There are epidemiological evidences of increased breast and colon cancer risk in shift workers. An inhibition of the pineal gland function with exposure to the constant light (LL) regimen promoted carcinogenesis whereas the light deprivation inhibits the carcinogenesis. Treatment with pineal indole hormone melatonin inhibits carcinogenesis in pinealectomized rats or animals kept at the standard light/dark regimen (LD) or at the LL regimen. These observations might lead to use melatonin for cancer prevention in groups of humans at risk of light pollution.

Implementing a night-shift clinical nurse specialist.

PubMed

Becker, Dawn Marie

2013-01-01

Night-shift nurses receive fewer educational opportunities and less administrative support than do day-shift staff, tend to be newer, with less experience and fewer resources, and experience greater turnover rates, stress, and procedural errors. In an attempt to bridge the gap between day- and night-shift nursing, a night-shift clinical nurse specialist (CNS) position was created in a midsized, community teaching hospital. The goal was to provide an advanced practice presence to improve patient outcomes, communication, education, and cost-effectiveness. The night-shift CNS participated in nursing education and skill certifications, communicated new procedures and information, and created a communication committee specifically for night-shift nurses. Through regular rounding and on-call notification, the CNS was available to every area of the hospital for consultation and clinical assistance and assisted with rapid responses, codes, and traumas. Providing education during night shift reduced overtime costs and increased morale, positively affecting turnover rates. The night-shift CNS position has improved morale and equalized support for night-shift nurses. More research, most notably in specific night-shift metrics, is necessary, and with the implementation of the role in additional facilities, more can be understood about improving patient care and nursing staff satisfaction during night shift.

Sleepiness and recovery in schedule change and the eighty-four hour workweek.

PubMed

Nordin, M; Knutsson, A

2001-12-01

The aims were to evaluate sleepiness and recovery during a schedule change, and during an 84-hours workweek. The control group (16 men) stayed on a six-week schedule, whereas the intervention group (12 men) transferred to a seven-week schedule. Sleepiness was estimated, using the KSS-scale, four times during the first and the third night in the fifth or sixth shift week. Recovery was assessed through four estimations on days one, three and five during the week off. Statistical testing was carried out using repeated measurement ANOVA. Sleepiness at night was affected by night (F = 4.90, p < 0.05) and hour (F = 33.64, p < 0.001) in both groups. The intervention group was sleepier during the first recovery day compared to the control group (F = 4.02, p < 0.05). Analysis of the 84-hour-week showed an effect of night (F = 8.98, p < 0.05) and hour (F = 71.60, p < 0.001) on night work, and day (F = 22.49, p < 0.01) and hour (F = 6.66, p < 0.05) on recovery. Sleepiness was more pronounced on the first recovery day (F = 23.08, p < 0.01). The seven-week schedule showed no effect that differed from that of the control group on sleepiness during the night shift. After the 84-hour workweek the workers recovered in about three days. The new schedules may affect the first recovery day negatively.

The effect of chronotype on sleepiness, fatigue, and psychomotor vigilance of ICU nurses during the night shift.

PubMed

Reinke, Laurens; Özbay, Yusuf; Dieperink, Willem; Tulleken, Jaap E

2015-04-01

In general, sleeping and activity patterns vary between individuals. This attribute, known as chronotype, may affect night shift performance. In the intensive care unit (ICR), night shift performance may impact patient safety. We have investigated the effect of chronotype and social demographics on sleepiness, fatigue, and night shift on the performance of nurses. This was a prospective observational cohort study which assessed the performance of 96 ICU night shift nurses during the day and night shifts in a mixed medical-surgical ICU in the Netherlands. We determined chronotype and assessed sleeping behaviour for each nurse prior to starting shift work and before free days. The level of sleepiness and fatigue of nurses during the day and night shifts was determined, as was the effect of these conditions on psychomotor vigilance and mathematical problem-solving. The majority of ICU nurses had a preference for early activity (morning chronotype). Compared to their counterparts (i.e. evening chronotypes), they were more likely to nap before commencing night shifts and more likely to have young children living at home. Despite increased sleepiness and fatigue during night shifts, no effect on psychomotor vigilance was observed during night shifts. Problem-solving accuracy remained high during night shifts, at the cost of productivity. Most of the ICU night shift nurses assessed here appeared to have adapted well to night shift work, despite the high percentage of morning chronotypes, possibly due to their 8-h shift duration. Parental responsibilities may, however, influence shift work tolerance.

Association of shiftwork and immune cells among police officers from the Buffalo Cardio-Metabolic Occupational Police Stress study.

PubMed

Wirth, Michael D; Andrew, Michael E; Burchfiel, Cecil M; Burch, James B; Fekedulegn, Desta; Hartley, Tara A; Charles, Luenda E; Violanti, John M

2017-01-01

Shift workers suffer from a constellation of symptoms associated with disruption of circadian rhythms including sleep abnormalities, and abnormal hormone secretion (e.g. melatonin, cortisol). Recent, but limited, evidence suggests that shift workers have elevated levels of circulating white blood cells (WBCs) compared to their day working counterparts. Interestingly, recent reviews highlight the strong linkage between the immune system and circadian rhythms which includes, but is not limited to, circulating cell populations and functions. The elevated levels of these WBCs may be associated with the increased chronic disease risk observed among this group. The purpose of this analysis was to examine the cross-sectional association between long- and short-term (3, 5, 7, and 14 days) shiftwork (SW) and counts of WBCs among officers in the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) cohort. Data collection for this analysis took place among 464 police officers working in Buffalo, New York, USA between 2004 and 2009. Precise SW histories were obtained using electronic payroll records. Officers were assigned a shift type based on the shift (i.e. day, evening, night) that they spent a majority (i.e. ≥50%) of their time from 1994 to the data collection date for long-term SW. The same process was applied to SW over 3, 5, 7, and 14 days prior to data collection. A fasted blood sample collected in the morning of a non-work day was used for characterization of WBCs (total), neutrophils, monocytes, lymphocytes, eosinophils, and basophils. Potential confounding factors included demographic characteristics (e.g. age, sex, race), occupational characteristics (e.g. rank), health behaviors (e.g. smoking, alcohol consumption, diet), anthropometrics, and other biomarkers (e.g. lipids, hemoglobin A1C, leptin). Generalized linear models were used to estimate least square means of the immune cells according to SW categorization for long- and short-term SW histories. Compared to the day shift group, those working long-term night shifts had greater absolute numbers of total WBCs, neutrophils, lymphocytes, and monocytes (all p < 0.05). Those working mainly on the night shift over 7-days had elevated counts of WBCs, lymphocytes, and monocytes (p < 0.05) compared to those mainly working day shifts. Results based on 3-, 5-, and 14-day SW were similar to the 7-day results. This study corroborates other studies with similar findings. However, this analysis provided insights into the effect of both long- and short-term SW on the number of circulating WBCs. SW may lead to disruption of circadian-influenced components of the immune system, which in term, may result in various chronic diseases. These findings, plus previous findings, may provide evidence that SW may lead to immune system dysregulation. Future research is needed to understand whether increases in immune cells among shift workers may be associated with the increased disease risk among this group.

Do Circadian Preferences Influence the Sleep Patterns of Night Shift Drivers?

PubMed Central

Narciso, Fernanda V.; Esteves, Andrea M.; Oliveira e Silva, Luciana; Bittencourt, Lia R.A.; Silva, Rogerio S.; Pires, Maria Laura N.; Tufik, Sergio; de Mello, Marco Tulio

2013-01-01

Objective The objective of this study was to analyze the effect of individual circadian preferences of drivers with fixed night work schedules on sleep patterns. Subjects and Methods A total of 123 professional drivers, 32 indifferent preference drivers and 91 morning preference drivers of an intermunicipality and interstate bus transportation company were evaluated. All drivers underwent polysomnographic recordings after their shifts. Furthermore, they filled out a questionnaire that contained sociodemographic and health questions. The Horne and Östberg questionnaire was used to assess the subjects' morningness-eveningness preference. Results The mean age was 42.54 ± 6.98 years and 82 (66.66%) of the drivers had worked for ≥15 years. A significant effect on rapid eye movement (REM) was observed in the morning preference drivers. They showed an increased sleep latency and an REM sleep percentage of 5% of the total REM time. This reveals a significant effect on sleep architecture associated with work time. Conclusion The drivers reported that morning preference had a significant effect on their sleep pattern indicating less REM sleep and longer REM sleep latency in the morning preference group. Thus, it is important to evaluate interactions between individual aspects of health and other parameters, such as sleep quality and work organizational factors, to promote night shift workers' health and well-being. PMID:23988815

Do circadian preferences influence the sleep patterns of night shift drivers?

PubMed

Narciso, Fernanda V; Esteves, Andrea M; Oliveira e Silva, Luciana; Bittencourt, Lia R A; Silva, Rogerio S; Pires, Maria Laura N; Tufik, Sergio; de Mello, Marco Tulio

2013-01-01

The objective of this study was to analyze the effect of individual circadian preferences of drivers with fixed night work schedules on sleep patterns. A total of 123 professional drivers, 32 indifferent preference drivers and 91 morning preference drivers of an intermunicipality and interstate bus transportation company were evaluated. All drivers underwent polysomnographic recordings after their shifts. Furthermore, they filled out a questionnaire that contained sociodemographic and health questions. The Horne and Östberg questionnaire was used to assess the subjects' morningness-eveningness preference. The mean age was 42.54 ± 6.98 years and 82 (66.66%) of the drivers had worked for ≥15 years. A significant effect on rapid eye movement (REM) was observed in the morning preference drivers. They showed an increased sleep latency and an REM sleep percentage of 5% of the total REM time. This reveals a significant effect on sleep architecture associated with work time. The drivers reported that morning preference had a significant effect on their sleep pattern indicating less REM sleep and longer REM sleep latency in the morning preference group. Thus, it is important to evaluate interactions between individual aspects of health and other parameters, such as sleep quality and work organizational factors, to promote night shift workers' health and well-being. © 2013 S. Karger AG, Basel.

A study comparing the hypnotic efficacies and residual effects on actual driving performance of midazolam 15 mg, triazolam 0.5 mg, temazepam 20 mg and placebo in shiftworkers on night duty

DOT National Transportation Integrated Search

1988-11-01

The purpose of the study was to determine the hypnotic efficacy and residual effects of three hypnotics administered for the treatment of transient insomnia in the day-sleep of rotating shift workers. The average duration of day-sleep in rotating shi...

Ups and Downs Associated with Implementing Shift Schedules on a Southern Harvesting Operation

Treesearch

D. Mitchell

2012-01-01

Extended working hours can increase the number of hours that equipment is available to perform work, but how effective are workers during those additional evening/night hours? A study was conducted in Alabama to compare daytime and nighttime production rates of a feller-buncher. The study was installed in a first thinning of a single-aged loblolly pine (Pinus taeda)...

Reduction of Sleep Deprivation and Fatigue in Mass Transit Rail Operators.

PubMed

Haynes, Ajeenah L

2017-08-01

Sleep and work schedules differ considerably between rail workers and the broader U.S. workforce. Due to extended work hours and night shift schedules, train and engine service workers who operate passenger trains or move freight are most vulnerable to fatigue. This article addresses the need for comprehensive fatigue risk management systems (FRMS) for rail operators. Using a transactional ergonomic perspective, FRMS are discussed with a focus on fatigue education and administrative controls to reduce feelings of tiredness, low motivation, poor concentration, and low physical activity among mass transit rail operators. Recommendations for intervention implementation and evaluation are provided.

No first night shift effect observed following a nocturnal main sleep and a prophylactic 1-h afternoon nap.

PubMed

Kosmadopoulos, Anastasi; Zhou, Xuan; Roach, Gregory D; Darwent, David; Sargent, Charli

Neurobehavioural impairment on the first night shift is often greater than on subsequent night shifts due to extended wakefulness. The aim of the study was to determine whether a 1-h afternoon nap prior to the first night shift is sufficient to produce neurobehavioural performance at levels comparable to the second night shift. Twelve male volunteers (mean age 22.9 years) participated in a laboratory protocol that simulated two 12-h night shifts. A nap preceded the first shift and a 7-h daytime sleep was scheduled between shifts. Neurobehavioural performance and subjective sleepiness measured across each night did not significantly differ between first and second shifts.

A work-life perspective on sleep and fatigue—looking beyond shift workers

PubMed Central

SKINNER, Natalie; DORRIAN, Jill

2015-01-01

This study examines sleep and fatigue through a work-life lens. Whilst most often thought of as an issue for shift workers, this study observed that self-reported insufficient sleep and fatigue were prevalent for workers on standard daytime schedules. Using a representative sample of 573 daytime workers (51.3% men; 70.7% aged 25−54 yr) from one Australian state, it was observed that 26.4% of daytime workers never or rarely get the seven hours of sleep a night that is recommended for good health. Those with parenting responsibilites (29.4%) or working long (45+) hours (37.4%) were most likely to report insufficient sleep. Whereas mothers in full-time work were most likely to report frequent fatigue (42.5%). This study highlights the common experience of insufficient sleep and fatigue in a daytime workforce, with significant implications for health and safety at work and outside of work. Stronger and more effective legislation addressing safe and ‘decent’ working time is clearly needed, along with greater awareness and acceptance within workplace cultures of the need to support reasonable workloads and working hours. PMID:26027709

Shift work at young age is associated with increased risk of multiple sclerosis in a Danish population.

PubMed

Gustavsen, S; Søndergaard, H B; Oturai, D B; Laursen, B; Laursen, J H; Magyari, M; Ullum, H; Larsen, M H; Sellebjerg, F; Oturai, A B

2016-09-01

Epidemiological studies suggest an important role for environmental factors in developing multiple sclerosis (MS). Furthermore several studies have indicated that the effect of environmental factors may be especially pronounced in adolescents. Recently only one study investigated and found that shift work at young age is associated with an increased risk of developing MS. In this study we focused on the effect of shift work in the vulnerable period between 15-19 years. The aim of this study was to investigate the association between shift work at young age and the risk of developing MS. We performed a large case-control study including 1723 patients diagnosed with MS and 4067 controls. MS patients were recruited from the Danish Multiple Sclerosis Biobank and controls from The Danish Blood Donor Study. Information on working patterns and lifestyle factors was obtained using a comprehensive lifestyle-environmental factor questionnaire with participants enrolled between 2009 and 2014. Logistic regression models were used to investigate the association between shift work at age 15-19 years and the subsequent risk of MS and were controlled for effects due to established MS risk factors. We found a statistically significant association when total numbers of night shifts were compared with non-shift workers. For every additional 100 night shifts the odds ratio (OR) for MS was 1.20 (95% confidence interval (CI), 1.08-1.34, p=0.001). Increasing intensity of shift work also increased MS risk. For every additional night per month the OR was 1.04 (95% CI, 1.01-1.06, p=0.002). Duration of shift work in years was not associated with risk of MS. This study supports a statistically significant association between shift work at age 15-19 years and MS risk. Copyright © 2016 Elsevier B.V. All rights reserved.

Association between rotating night shift work and risk of coronary heart disease among women

PubMed Central

Vetter, Céline; Devore, Elizabeth E.; Wegrzyn, Lani R.; Massa, Jennifer; Speizer, Frank E.; Kawachi, Ichiro; Rosner, Bernard; Stampfer, Meir J.; Schernhammer, Eva S.

2016-01-01

Importance Prospective studies linking shift work to coronary heart disease (CHD) have been inconsistent and limited by short follow-up. Objective Determine whether rotating night shift work is associated with CHD risk. Design, Setting and Participants Prospective cohort study of 189,158 initially healthy women followed over 24 years in the Nurses' Health Studies (NHS (1988-2012): N=73,623, and NHS2 (1989-2013): N=115,535). Exposure Questionnaire-based lifetime history of rotating night shift work (≥3 night shifts/month, plus day and evening shifts) at baseline; also updated every 2-4yrs in NHS2. Main Outcomes and Measures Incident CHD, i.e. non-fatal myocardial infarction, CHD death, angiogram-confirmed angina pectoris, coronary artery bypass grafting (CABG), stents, and angioplasty. Results During follow-up, 7,303 incident CHD cases in NHS (mean age at baseline: 54.5yrs) and 3,519 in NHS2 (34.8yrs) occurred. In multivariable adjusted Cox proportional hazards models, increasing years of baseline rotating night shift work were associated with a significantly higher CHD risk in both cohorts (NHS: age-standardized incidence rate (IR)<5yrs per 100,000 person-years=435.1, hazard ratio (HR)<5yrs=1.02, 95% confidence interval (CI)=0.97-1.08, IR5-9yrs=525.7, HR5-9yrs=1.12, 95%CI=1.02-1.22, IR≥10yrs=596.9, HR≥10yrs=1.18, 95%CI=1.10-1.26; Ptrend<0.001; NHS2: IR<5yrs=130.6, HR<5yrs=1.05, 95%CI=0.97-1.13; IR5-9yrs=151.6, HR5-9yrs=1.12, 95%CI=0.99-1.26; HR≥10yrs=178.0, HR≥10yrs=1.15, 95%CI=1.01-1.32; Ptrend=0.01), compared to women who never worked rotating night shifts (NHS: IRnever=425.5, NHS2: IRnever=122.6). In NHS, the association between duration of rotating night shift work and CHD was stronger in the first half of follow-up (IR<5yrs=382.4, HR<5yrs=1.10, 95%CI=1.01-1.21, IR5-9yrs=483.1, HR5-9yrs=1.19, 95%CI=1.03-1.39, IR≥10yrs=494.4, HR≥10yrs=1.27, 95%CI =1.13-1.42, Ptrend <0.001) than in the second half (IR<5yrs=424.8, HR<5yrs=0.98, 95%CI=0.92-1.05, IR5-9yrs=520.7, HR5-9yrs=1.08, 95%CI=0.96-1.21, IR≥10yrs=556.2, HR≥10yrs=1.13, 95%CI =1.04-1.24, Ptrend=0.004, PInteraction=0.02), suggestive of waning risk after cessation of shift work. Longer time since quitting shift work was associated with decreased CHD risk among ever shift workers in NHS2 (Ptrend<0.001). Conclusions and Relevance Among women who worked as registered nurses, longer duration of rotating night shift work was associated with a statistically significant, but small absolute increase in CHD risk. Further research is needed to explore whether the association is related to specific work hours and individual characteristics. PMID:27115377

Work schedules and 11-year progression of carotid atherosclerosis in middle-aged Finnish men.

PubMed

Wang, Aolin; Arah, Onyebuchi A; Kauhanen, Jussi; Krause, Niklas

2015-01-01

This study investigated the relationship between different work schedules and progression of carotid atherosclerosis, an early indicator of cardiovascular disease (CVD). We studied 621 men, aged 42-60 years, in the prospective Kuopio Ischemic Heart Disease Risk Factor Study cohort. Using multivariable regressions adjusting for 22 covariates including total time worked during follow-up, we evaluated the associations of baseline work schedules with 11-year progression of ultrasonographically assessed carotid intima-media thickness (IMT), and their variation by preexisting CVD. Standard daytime work, weekend shifts, and evening/night/rotating shifts were associated with 31%, 37%, and 33% increases in IMT, respectively. Compared to daytime workers, weekend workers experienced a faster progression of carotid atherosclerosis [relative change ratio (RCR) = 1.05, 95% CI: 1.00-1.09)]. This ratio was higher among men who had preexisting CVD. Weekend shifts, more than standard daytime work, appear to accelerate carotid atherosclerosis progression among middle-aged Finnish men, especially those with pre-existing CVD. © 2014 Wiley Periodicals, Inc.

"A hard day's night?" The effects of Compressed Working Week interventions on the health and work-life balance of shift workers: a systematic review.

PubMed

Bambra, C; Whitehead, M; Sowden, A; Akers, J; Petticrew, M

2008-09-01

To systematically review studies of the effects of the Compressed Working Week on the health and work-life balance of shift workers, and to identify any differential impacts by socio-economic group. Systematic review. Following QUORUM guidelines, published or unpublished experimental and quasi-experimental studies were identified. Data were sourced from 27 electronic databases, websites, bibliographies, and expert contacts. Fourty observational studies were found. The majority of studies only measured self-reported outcomes and the methodological quality of the included studies was not very high. Interventions did not always improve the health of shift workers, but in the five prospective studies with a control group, there were no detrimental effects on self-reported health. However, work-life balance was generally improved. No studies reported differential impacts by socio-economic group; however, most of the studies were conducted on homogeneous populations. This review suggests that the Compressed Working Week can improve work-life balance, and that it may do so with a low risk of adverse health or organisational effects. However, better designed studies that measure objective health outcomes are needed.

Night shift fatigue among anaesthesia trainees at a major metropolitan teaching hospital.

PubMed

Lancman, B M

2016-05-01

Night shifts expose anaesthesia trainees to the risk of fatigue and, potentially, fatigue-related performance impairment. This study examined the workload, fatigue and coping strategies of anaesthesia trainees during night shifts. A blinded survey-based study was undertaken at a major single centre metropolitan teaching hospital in Australia. All ten anaesthesia trainees who worked night shifts participated. The survey collected data on duration of night shifts, workload, and sleep patterns. Fatigue was assessed using the Karolinska Sleepiness Scale (KSS). There were 93 night shifts generating data out of a potential 165. Trainees tended to sleep an increasing amount before their shift as the nights progressed from 1 to 5. Night 1 was identified as an 'at risk' night due to the amount of time spent awake before arriving at work (32% awake for U+003E8 hours); on all other nights trainees were most likely to have slept 6-8 hours. The KSS demonstrated an increase in sleepiness of 3 to 4 points on the scale from commencement to conclusion of a night shift. The Night 1 conclusion sleepiness was markedly worse than any other night with 42% falling into an 'at-risk' category. The findings demonstrate fatigue and inadequate sleep in anaesthesia trainees during night shifts in a major metropolitan teaching hospital. The data obtained may help administrators prepare safer rosters, and junior staff develop improved strategies to reduce the likelihood of fatigue.

Nurses' sleep quality, work environment and quality of care in the Spanish National Health System: observational study among different shifts

PubMed Central

Gómez-García, Teresa; Ruzafa-Martínez, María; Fuentelsaz-Gallego, Carmen; Madrid, Juan Antonio; Rol, Maria Angeles; Martínez-Madrid, María José; Moreno-Casbas, Teresa

2016-01-01

Objective The main objective of this study was to determine the relationship between the characteristics of nurses' work environments in hospitals in the Spanish National Health System (SNHS) with nurse reported quality of care, and how care was provided by using different shifts schemes. The study also examined the relationship between job satisfaction, burnout, sleep quality and daytime drowsiness of nurses and shift work. Methods This was a multicentre, observational, descriptive, cross-sectional study, centred on a self-administered questionnaire. The study was conducted in seven SNHS hospitals of different sizes. We recruited 635 registered nurses who worked on day, night and rotational shifts on surgical, medical and critical care units. Their average age was 41.1 years, their average work experience was 16.4 years and 90% worked full time. A descriptive and bivariate analysis was carried out to study the relationship between work environment, quality and safety care, and sleep quality of nurses working different shift patterns. Results 65.4% (410) of nurses worked on a rotating shift. The Practice Environment Scale of the Nursing Work Index classification ranked 20% (95) as favourable, showing differences in nurse manager ability, leadership and support between shifts (p=0.003). 46.6% (286) were sure that patients could manage their self-care after discharge, but there were differences between shifts (p=0.035). 33.1% (201) agreed with information being lost in the shift change, showing differences between shifts (p=0.002). The Pittsburgh Sleep Quality Index reflected an average of 6.8 (SD 3.39), with differences between shifts (p=0.017). Conclusions Nursing requires shift work, and the results showed that the rotating shift was the most common. Rotating shift nurses reported worse perception in organisational and work environmental factors. Rotating and night shift nurses were less confident about patients' competence of self-care after discharge. The most common nursing care omissions reported were related to nursing care plans. For the Global Sleep Quality score, difference were found between day and night shift workers. PMID:27496241

Investigating Cortisol Production and Pattern as Mediators in the Relationship Between Shift Work and Cardiometabolic Risk.

PubMed

Ritonja, Jennifer; Aronson, Kristan J; Day, Andrew G; Korsiak, Jill; Tranmer, Joan

2018-05-01

Shift work is a risk factor for many diseases, including cardiovascular disease. Although the biological pathways are still unclear, it is hypothesized that cortisol disruption during night work is an intermediate. The objective of this study is to determine whether total cortisol production and cortisol pattern mediate the relationship between current shift work and cardiometabolic risk (CMR) among female hospital employees. A cross-sectional study was conducted among 326 female employees (166 rotating shift workers, 160 day workers), recruited from a hospital in Southeastern Ontario, Canada, during 2011 to 2014. Participants completed a baseline interview, questionnaire, and clinical exam. Urine samples were collected over two 24-hour periods and used to analyze creatinine-adjusted cortisol, which was then used to calculate total cortisol production (AUC G ), and pattern (AUC I ). Mediation analysis was performed to test the mediating effect of cortisol in the relationship between shift work and a continuous CMR score. Current shift work is associated with a 0.52 higher CMR score (95% CI: 0.15, 0.89), a lower cortisol output (AUC G ), and a flatter pattern (AUC I ) over a 2-day period. AUC G is a partial mediator in the relationship between shift work and CMR, whereas AUC I is not. AUC G is also associated with CMR while controlling for shift work, suggesting that lower total cortisol production is also linked to CMR in non-shift workers. Total cortisol production is a partial mediator in the relationship between rotating shift work and CMR among female hospital employees, whereas cortisol pattern is not a mediator. Copyright © 2018 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Longhouser, G.A. Jr.

Human beings are diurnal species, normally active by day and asleep by night. Yet over thirty million Americans struggle with work schedules that include an off-normal work effort. The railroads, law enforcement, health services, Department of Defense, factory workers, chemical plants and public services, communications and utility workers must provide some form of around-the-clock effort. Shift work has been around since the advent of recorded history. There has always been a need for some type of off-normal service and assistance. The impact of shift work is replete with tales and factual evidence of an increased personnel error rate; disorders, bothmore » personal and family, and of course, increased accident events. In recent memory, the Three Mile Island Nuclear Plant incident, Union Carbide`s explosion in Bhopal, and the Chernobyl Nuclear Plant catastrophe all occurred during off-normal working hours. Yet management overall has done little to correct the production-driven twelve hour, seven day week shift mentality of the nineteenth century. Most schedules in use today are nothing more than cosmetic variations of the old production schedules. This could be driven by a management consideration of the worker`s response to change coupled with a reluctant buy-in of responsibility for the effects of change. Florida Power Corporation has developed for its nuclear security force, a unique work schedule which attempts to employ the sound principles of circadian rhythms coupled with a comprehensive training program to counter the problems associated with shift work. The results over the last four years have seen a marked reduction in the generic problems of personnel errors, absenteeism, unscheduled overtime and turnover rates. Utilization and understanding of this scheduling process for rotational shift work needs to be assessed to determine if the benefits are site specific or provide an expected response to the problems of shift work.« less

Mental distress among shift workers in Norwegian offshore petroleum industry--relative influence of individual and psychosocial work factors.

PubMed

Ljoså, Cathrine Haugene; Tyssen, Reidar; Lau, Bjørn

2011-11-01

This study aimed to investigate the association between individual and psychosocial work factors and mental distress among offshore shift workers in the Norwegian petroleum industry. All 2406 employees of a large Norwegian oil and gas company, who worked offshore during a two-week period in August 2006, were invited to participate in the web-based survey. Completed questionnaires were received from 1336 employees (56% response rate). The outcome variable was mental distress, assessed with a shortened version of the Hopkins Symptom Checklist (HSCL-5). The following individual factors were adjusted for: age, gender, marital status, and shift work locus of control. Psychosocial work factors included: night work, demands, control and support, and shift work-home interference. The level of mental distress was higher among men than women. In the adjusted regression model, the following were associated with mental distress: (i) high scores on quantitative demands, (ii) low level of support, and (iii) high level of shift work-home interference. Psychosocial work factors explained 76% of the total explained variance (adjusted R (²)=0.21) in the final adjusted model. Psychosocial work factors, such as quantitative demands, support, and shift work-home interference were independently associated with mental distress. Shift schedules were only univariately associated with mental distress.

Effect of working consecutive night shifts on sleep time, prior wakefulness, perceived levels of fatigue and performance on a psychometric test in emergency registrars.

PubMed

Haire, Julia Christine Lydia; Ferguson, Sally Anne; Tilleard, James D; Negus, Paul; Dorrian, Jillian; Thomas, Matthew Jw

2012-06-01

To evaluate the effect of working consecutive night shifts on sleep time, prior wakefulness, perceived levels of fatigue and psychomotor performance in a group of Australian emergency registrars. A prospective observational study with a repeated within-subjects component was conducted. Sleep time was determined using sleep diaries and activity monitors. Subjective fatigue levels and reciprocal reaction times were evaluated before and after day and night shifts. A total of 11 registrars participated in the study with 120 shifts analysed. Sleep time was found to be similar during consecutive night and day shifts. The mean number of hours spent awake before the end of a night shift was 14.33. Subjective fatigue scores were worst at the end of a night shift. There was no difference in reciprocal reaction time between the end of night shift and the start of day shift. Registrars sleep a similar amount of time surrounding night and day shifts. Despite reporting the highest levels of fatigue at the end of a night shift, there is no significant difference in reaction times at the end of night shift compared with the beginning of day shift. This correlates with the finding that at the end of night shift the registrars have been awake for less than 16 h, which is the point at which psychomotor performance is expected to decline. © 2012 The Authors. EMA © 2012 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Measuring subjective sleepiness at work in hospital nurses: validation of a modified delivery format of the Karolinska Sleepiness Scale.

PubMed

Geiger Brown, Jeanne; Wieroney, Margaret; Blair, Lori; Zhu, Shijun; Warren, Joan; Scharf, Steven M; Hinds, Pamela S

2014-12-01

Sleepiness during the work shift is common and can be hazardous to workers and, in the case of nurses, to patients under their care. Thus, measuring sleepiness in occupational studies is an important component of workplace health and safety. The Karolinska Sleepiness Scale (KSS) is usually used as a momentary assessment of a respondent's state of sleepiness; however, end-of-shift measurement is sometimes preferred based on the study setting. We assessed the predictive validity of the KSS as an end-of-shift recall measurement, asking for "average" sleepiness over the shift and "highest" level of sleepiness during the shift. Hospital registered nurses (N=40) working 12-h shifts completed an end-of-shift diary over 4 weeks that included the National Aeronautical and Space Administration Task Load Index (NASA-TLX) work intensity items and the KSS (498 shifts over 4 weeks). Vigilant attention was assessed by measuring reaction time, lapses, and anticipations using a 10-min performance vigilance task (PVT) at the end of the shift. The Horne-Ostberg Questionnaire, Epworth Sleepiness Scale, General Sleep Disturbance Scale, and Cleveland Sleep Habits Questionnaire were also collected at baseline to assess factors that could be associated with higher sleepiness. We hypothesized that higher KSS scores would correlate with vigilant attention parameters reflective of sleepiness (slower reaction times and more lapses and anticipations on a performance vigilance task) and also with those factors known to produce higher sleepiness. These factors included the following: (1) working night shifts, especially for those with "morningness" trait; (2) working sequential night shifts; (3) having low physical and mental work demands and low time pressure; (4) having concomitant organic sleep disorders; and (5) having greater "trait" sleepiness (Epworth Sleepiness Scale). Linear mixed models and generalized linear mixed models were used to test associations that could assess the predictive validity of this format of administering the KSS. Greater sleepiness, as measured by higher KSS scores, was found on shifts with nurses working night shift, the third sequential night compared to the first, those with sleep disorder symptoms (especially insomnia), and in nurses with trait sleepiness on the Epworth scale. Less sleepiness (lower KSS scores) was seen in shifts with a high level of time pressure and in nurses with a biologic predisposition to be more alert in the morning (morningness trait) who worked the day shift. We found partial support for using the Karolinska Sleepiness Scale in the recalled format based on our multiple tests of predictive validity.

Rapid counterclockwise shift rotation in air traffic control: effects on sleep and night work.

PubMed

Signal, T Leigh; Gander, Philippa H

2007-09-01

In Air Traffic Control, counterclockwise rapidly rotating shift schedules are often employed but may result in significant sleep loss. This has potential consequences for performance, particularly if a night shift is worked. As part of a large-scale field study, the pattern of sleep across a 4-d counterclockwise, rapidly rotating schedule (afternoon, day, morning, night shift) was documented and relationships between prior sleep and performance during the night shift were investigated. There were 28 controllers who completed 4 periods of data collection which included 2 d before and 2 d after a 4-d shift cycle. Sleep was recorded using an actigraph and sleep diary, and performance on each night shift was measured three times using the Psychomotor Vigilance Task. Across the work week, sleep duration decreased largely due to earlier rise times associated with shift start times moving backward. In the short turn-around between the morning and night shift, 90% of controllers slept for an average of 2.2 h. Improved performance on the night shift was related only to longer periods of sleep the night prior. This study demonstrates that a 4-d counterclockwise, rapidly rotating schedule results in a progressive reduction in sleep and consequently the rapid accumulation of a sleep debt. To help maintain their performance on the night shift, it is recommended that controllers attempt to obtain at least 6 h sleep the night before a night shift. It is also recommended that ATC providers educate their workforce about this issue.

Rotating night shifts too quickly may cause anxiety and decreased attentional performance, and impact prolactin levels during the subsequent day: a case control study.

PubMed

Chang, Yu-San; Chen, Hsiang-Lan; Wu, Yu-Hsuan; Hsu, Chung-Yao; Liu, Ching-Kuan; Hsu, Chin

2014-08-05

We investigated circadian changes and effects on mood, sleep-related hormones and cognitive performance when nurses worked consecutive night shifts in a rapidly rotating shift system. Daytime cognitive function, sleep propensity and sleep-related hormones (growth hormone, cortisol, prolactin, thyrotropin) were compared after participants worked two and four consecutive night shifts. Twenty-three off-duty nurses, 20 nurses working two consecutive night shifts and 16 nurses working four consecutive night shifts were enrolled. All participants completed the Maintenance of Wakefulness Test, State-Trait Anxiety Inventory, Stanford Sleepiness Scale, visual attention tasks (VAT), Wisconsin Card Sorting Test, and modified Multiple Sleep Latency Test. Hormone levels were also measured four times throughout the day, at 2-h intervals. During the day, the participants in the night shift groups were less able to maintain wakefulness, had poor performance on VAT, and higher thyrotropin levels than did those in the off-duty group. Participants who worked two night shifts were better able to maintain wakefulness, had higher anxiety scale scores, poorer initial performance and lack of learning effect on VAT, and higher prolactin levels compared with those who worked four night shifts. There were no differences in cortisol levels between the two- and four- shift groups. Rotating night shifts too quickly may cause anxiety and decreased attentional performance, and may impact daytime prolactin levels after night shifts. It is possible that the two-shift group had a higher cortisol level than did the four-shift group, which would be consistent with the group's higher state anxiety scores. The negative findings may be due to the small sample size. Further studies on the effects of consecutive night shifts on mood and cortisol levels during the daytime after sleep restriction would be valuable.

Is health, measured by work ability index, affected by 12-hour rotating shift schedules?

PubMed

Yong, Mei; Nasterlack, Michael; Pluto, Rolf-Peter; Elmerich, Kathrin; Karl, Dorothee; Knauth, Peter

2010-07-01

Two forms of continuously forward rotating 12-h shift schedules exist at BASF's Ludwigshafen site. These shift schedules were compared with a daytime working system to investigate potential differential effects on employee's health status assessed with the Work Ability Index (WAI). In the 3 x 12 system, a 12-h day shift is followed 24 h later by a 12-h night shift, and after a day off the employee returns to the day shift. The 4 x 12 schedule follows the same pattern except that there are 2 days off between the night and next day shift. A total of 924 participants (278 3 x 12 and 321 4 x 12 shiftworkers and 325 day workers) were recruited. A self-administered questionnaire was used to obtain information about shiftwork schedule, demographic characteristics, and lifestyle and social factors, and the WAI was applied. The outcomes of interest were the WAI sum score and its seven dimensions. In examining the relationship with the WAI categories, a Proportional Odds Model (POM) was used to identify the potential determinants. Logistic regression models were used to estimate the impact of age on single dimensions of WAI after adjustment for potential confounding factors. Increasing age and obesity (BMI > or = 30) were the only significant determinants of poorer WAI. Although a positive association was found linking the second WAI dimension (work ability in relation to job demands) with age, an inverse association was demonstrated consistently between age and the third and fourth WAI dimensions, i.e., number of diagnosed diseases and estimated work impairment due to disease, after adjustment for potential confounders. The age-dependency was moderate overall, but seemed to be stronger among shift- than day workers, although this difference did not reach statistical significance. There was no significant differential impact of the working time systems on the WAI sum score or on the individual WAI dimensions. Thus, there is no indication of an excessive adverse health impact of these shift schedules compared to day work, to the extent that health can be measured by the WAI.

Polysomnographic Sleep and Circadian Temperature Rhythms as a Function of Prior Shift Work Exposure in Retired Seniors.

PubMed

Monk, Timothy H; Buysse, Daniel J; Billy, Bart D; Fletcher, Mary E; Kennedy, Kathy S

2013-04-29

In an earlier published telephone interview study (n > 1,000) we have shown that retired shift workers subjectively report worse sleep than retired day workers. This laboratory study sought to determine whether these findings held up when objective polysomnograhic (PSG) measures of sleep were taken and whether retirees' circadian temperature rhythms differed as a function of shift work exposure. All completers of the telephone interview were invited to attend a 36-hour laboratory study for which participants were paid. This involved continuous core body temperature measurement (using an ingestible pill-based system) and 2 nights of PSG. Shift work exposure (plus other measures) was collected by taking a detailed work history. The second laboratory night was scored into sleep stages. Post hoc, we divided participants into 4 shift work exposure groups: 0 years (ie, no exposure to shift work), 1 to 7 years, 7 to 20 years, and >20 years. Sample sizes were 11, 16, 15, and 15, respectively, with approximate equality in mean age (71.7 years of age, 69.1 years of age, 70.0 years of age, and 70.4 years of age, respectively) and percent male (63%, 50%, 67%, and 73%, respectively). Shift work exposure was associated with worse PSG sleep in a dose-related fashion. The percentages of participants with sleep efficiency, 80% for the 0 years, 1 to 7 years, 7 to 20 years, and >20 years groups were 36%, 63%, 67%, and 73%, respectively ( P < 0.01), and the percentages with total sleep time (TST), 6 hours were 36%, 56%, 53%, and 73%, respectively ( P < 0.01). From the circadian rhythm record, shift work exposure appeared to result ( P = 0.06) in an increased spread of phase angles (difference between habitual bedtime and time of temperature trough). In conclusion, it appears likely that shift work may be related to a scarring of sleep and circadian rhythms. This may be associated with a change in the relationship between habitual sleep timing and the phase of the circadian pacemaker.

[Shiftwork. Impact on health and safety in the working environment].

PubMed

Garbarino, S

2006-01-01

Biological rhythms are highly disrupted by night shiftwork (NSW), and any perturbation of social and family life negatively affects performance efficiency, health and social relations. These undesirable aspects have acute and chronic components. The effects manifest themselves not only as increased accidents' frequency, but also as sleep disturbances, excessive daytime sleepiness, psychosomatic disorders that may variously interact to configure a "shift-lag" syndrome, with acute and chronic manifestation. Chronic effects increase the risk of psychoneurotic, cardiovascular and gastrointestinal diseases. The effects of NSW on women are much more pronounced because of their reproductive function and family obligations. Recent Italian legislation (1999, 2003) on night-work has essentially recognised it as a new risk factor and has established that workers' health should be safeguarded through preventive check-ups and regular controls by occupational health physicians. This involves that now occupational health physicians are required to inform workers on coping strategies, and carefully assess health disorders with absolute or relative contraindications. Data from international literature and from our group production are revised and discussed.

[Effect of the night shift work on micturition patterns of nurses].

PubMed

Wang, Q; Hu, H; Liang, C; Wang, J; Xu, K X

2016-02-18

To compare the effects of rotational night shifts on the micturition patterns of female nurses. A total of 58 nurses without lower urinary tract symptoms were recruited, who worked in the Peking University People's Hospital during January and June in 2014. The nurses aged 20-43 years were divided into two groups, the night-shift group (n=28) and the non-shift group (n=30). The alcohol or coffee intaking were forbidden. In the night-shift group, nurses had worked on rotational shifts for at least 6 months. Their average age was (26.75±4.11) years. In the non-shift group, nurses took regular day-time work, whose average age was (27.80±5.60) years. A voiding diary was kept for 7 consecutive days at the end of 6 months, starting 2 days before their night duties until 4 days after completion of their night duties. For comparison, the non-shift group with regular shifts completed a 7-day voiding diary. In the 7-day recording voiding diary, the nurses were required to have the normal intake of liquid about 1 500-2 000 mL/d. The frequency volume charts of nocturia, the 8-hour interval urine production and frequency were compared between the two groups. Nocturia frequency was increased in the night-shift group [0.5 (0-2.4)] compared with the non-shift group [0 (0-2), P=0.02]. The volume of nocturia was increased in the night-shift group [125 mL (0-660 mL)] compared with the non-shift group [0 mL (0-340 mL), P<0.01]. The 8-hour interval indices showed that urine production changed with shift (P<0.01). In the consecutive 7 days, the nocturnal volume of the night-shift group increased on the day after night shift. When the night-shift nurses returned to daytime duty, the volume of urine decreased but nocturnal urine production remained high, and the frequency of nocturia also increased significantly (P<0.05). Compared with the 8-hour interval indices, the night-shift group's voiding volume [(542.35±204.66) mL] and voiding frequency (2.24±0.69) were more than those of the non-shift group at the afternoon time (from 2 pm to 10 pm). During the 8 h interval night time (from 10 pm to 6 am), the volume of nocturia in the night-shift group [(309.74±162.74) mL] was more than that in the non-shift group [(199.38±153.98) mL, P=0.01]; the frequency of nocturia in the night-shift group (1.31±0.52) was increased than that in the non-shift group (0.82±0.55, P<0.01). The rotational shifts affect the micturition patterns of nurses who go through the night shift work, which increases the volume and frequency of the nocturia.

[Effect of the night shift work on micturition patterns of nurses].

PubMed

Wang, Q; Hu, H; Liang, C; Wang, J; Xu, K X

2016-08-18

To compare the effects of rotational night shifts on the micturition patterns of female nurses. A total of 58 nurses without lower urinary tract symptoms were recruited, who worked in the Peking University People's Hospital during January and June in 2014. The nurses aged 20-43 years were divided into two groups, the night-shift group (n=28) and the non-shift group (n=30). The alcohol or coffee intaking were forbidden. In the night-shift group, nurses had worked on rotational shifts for at least 6 months. Their average age was (26.75±4.11) years. In the non-shift group, nurses took regular day-time work, whose average age was (27.80±5.60) years. A voiding diary was kept for 7 consecutive days at the end of 6 months, starting 2 days before their night duties until 4 days after completion of their night duties. For comparison, the non-shift group with regular shifts completed a 7-day voiding diary. In the 7-day recording voiding diary, the nurses were required to have the normal intake of liquid about 1 500-2 000 mL/d. The frequency volume charts of nocturia, the 8-hour interval urine production and frequency were compared between the two groups. Nocturia frequency was increased in the night-shift group [0.5 (0-2.4)] compared with the non-shift group [0 (0-2), P=0.02]. The volume of nocturia was increased in the night-shift group [125 mL (0-660 mL)] compared with the non-shift group [0 mL (0-340 mL), P<0.01]. The 8-hour interval indices showed that urine production changed with shift (P<0.01). In the consecutive 7 days, the nocturnal volume of the night-shift group increased on the day after night shift. When the night-shift nurses returned to daytime duty, the volume of urine decreased but nocturnal urine production remained high, and the frequency of nocturia also increased significantly (P<0.05). Compared with the 8-hour interval indices, the night-shift group's voiding volume [(542.35±204.66) mL] and voiding frequency (2.24±0.69) were more than those of the non-shift group at the afternoon time (from 2 pm to 10 pm). During the 8 h interval night time (from 10 pm to 6 am), the volume of nocturia in the night-shift group [(309.74±162.74) mL] was more than that in the non-shift group [(199.38±153.98) mL, P=0.01]; the frequency of nocturia in the night-shift group (1.31±0.52) was increased than that in the non-shift group (0.82±0.55, P<0.01). The rotational shifts affect the micturition patterns of nurses who go through the night shift work, which increases the volume and frequency of the nocturia.

Scheduled Evening Sleep and Enhanced Lighting Improve Adaptation to Night Shift Work in Older Adults

PubMed Central

Chinoy, Evan D.; Harris, Michael P.; Kim, Min Ju; Wang, Wei; Duffy, Jeanne F.

2017-01-01

Objectives We tested whether a sleep and circadian-based treatment shown to improve circadian adaptation to night shifts and attenuate negative effects on alertness, performance, and sleep in young adults would also be effective in older adults. Methods We assessed subjective alertness, sustained attention (psychomotor vigilance task, PVT), sleep duration (actigraphy), and circadian timing (salivary dim-light melatonin onset, DLMO) in eighteen older adults (57.2±3.8 y; mean±SD) in a simulated shift work protocol. Four day shifts were followed by three night shifts in the laboratory. Participants slept at home and were randomized to either the Treatment Group (scheduled evening sleep and enhanced lighting during the latter half of night shifts), or Control Group (ad lib sleep and typical lighting during night shifts). Results Compared to day shifts, alertness and sustained attention declined on the first night shift in both groups, and was worse in the latter half of the night shifts. Alertness and attention improved on nights 2 and 3 for the Treatment Group but remained lower for the Control Group. Sleep duration in the Treatment Group remained similar to baseline (6–7 h) following night shifts, but was shorter (3–5 h) following night shifts in the Control Group. Treatment Group circadian timing advanced by 169.3±16.1 min (mean±SEM) but did not shift (−9.7±9.9 min) in the Control Group. Conclusions The combined treatment of scheduled evening sleep and enhanced lighting increased sleep duration and partially aligned circadian phase with sleep and work timing, resulting in improved night shift alertness and performance. PMID:27566781

Physical occupational exposures and health expectancies in a French occupational cohort

PubMed Central

Head, Jenny; Stenholm, Sari; Singh Chungkham, Holendro; Goldberg, Marcel; Zins, Marie

2017-01-01

Objectives To examine the relationships of strenuous and hazardous working conditions and rotating shifts that involve night working with life expectancy in good perceived health and life expectancy without chronic disease. Methods The sample contained male gas and electricity workers from the French GAZEL cohort (n=13 393). Six measures of physical working conditions were examined: Self-reports from 1989 and 1990 of ergonomic strain, physical danger, rotating shifts that involve night working and perceived physical strain; company records of workplace injuries and a job-exposure matrix of chemical exposures. Partial healthy life expectancies (age 50–75) relating to (1) self-rated health and (2) chronic health conditions, obtained from annual questionnaires (1989–2014) and company records, were estimated using multistate life tables. The analyses were adjusted for social class and occupational grade. Results Participants with physically strenuous jobs and who had experienced industrial injuries had shorter partial life expectancy. More physically demanding and dangerous work was associated with fewer years of life spent in good self-rated health and without chronic conditions, with the exception of shift work including nights, where the gradient was reversed. Conclusions Strenuous and hazardous work may contribute to lost years of good health in later life, which has implications for individuals' quality of life as well as healthcare use and labour market participation. PMID:27655775

Linking better shiftwork arrangements with safety and health management systems.

PubMed

Kogi, Kazutaka

2004-12-01

Various support measures useful for promoting joint change approaches to the improvement of both shiftworking arrangements and safety and health management systems were reviewed. A particular focus was placed on enterprise-level risk reduction measures linking working hours and management systems. Voluntary industry-based guidelines on night and shift work for department stores and the chemical, automobile and electrical equipment industries were examined. Survey results that had led to the compilation of practicable measures to be included in these guidelines were also examined. The common support measures were then compared with ergonomic checkpoints for plant maintenance work involving irregular nightshifts. On the basis of this analysis, a new night and shift work checklist was designed. Both the guidelines and the plant maintenance work checkpoints were found to commonly cover multiple issues including work schedules and various job-related risks. This close link between shiftwork arrangements and risk management was important as shiftworkers in these industries considered teamwork and welfare services to be essential for managing risks associated with night and shift work. Four areas found suitable for participatory improvement by managers and workers were work schedules, ergonomic work tasks, work environment and training. The checklist designed to facilitate participatory change processes covered all these areas. The checklist developed to describe feasible workplace actions was suitable for integration with comprehensive safety and health management systems and offered valuable opportunities for improving working time arrangements and job content together.

What roles do team climate, roster control, and work life conflict play in shiftworkers' fatigue longitudinally?

PubMed

Pisarski, Anne; Barbour, Jennifer P

2014-05-01

The study aimed to examine shiftworkers fatigue and the longitudinal relationships that impact on fatigue such as team climate, work life conflict, control of shifts and shift type in shift working nurses. We used a quantitative survey methodology and analysed data with a moderated hierarchical multiple regression. After matching across two time periods 18 months apart, the sample consisted of 166 nurses from one Australian hospital. Of these nurses, 61 worked two rotating day shifts (morning & afternoon/evening) and 105 were rotating shiftworkers who worked three shifts (morning afternoon/evening and nights). The findings suggest that control over shift scheduling can have significant effects on fatigue for both two-shift and three-shift workers. A significant negative relationship between positive team climate and fatigue was moderated by shift type. At both Time 1 and Time 2, work life conflict was the strongest predictor of concurrent fatigue, but over time it was not. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Use of Circadian Lighting System to improve night shift alertness and performance of NRC Headquarters Operations Officers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, T.L.; Morisseau, D.; Murphy, N.M.

1995-04-01

The Nuclear Regulatory Commission`s (NRC) Headquarters Operations Officers (HOOs) receive and respond to events reported in the nuclear industry on a 24-hour basis. The HOOs have reported reduced alertness on the night shift, leading to a potential deterioration in their on-shift cognitive performance during the early morning hours. For some HOOs, maladaptation to the night shift was also reported to be the principal cause of: (a) reduced alertness during the commute to and from work, (b) poor sleep quality, and (c) personal lifestyle problems. ShiftWork Systems, Inc. (SWS) designed and installed a Circadian Lighting System (CLS) at both the Bethesdamore » and Rockville HOO stations with the goal of facilitating the HOOs physiological adjustment to their night shift schedules. The data indicate the following findings: less subjective fatigue on night shifts; improved night shift alertness and mental performance; higher HOO confidence in their ability to assess event reports; longer, deeper and more restorative day sleep after night duty shifts; swifter adaptation to night work; and a safer commute, particularly for those with extensive drives.« less

Can short-wavelength depleted bright light during single simulated night shifts prevent circadian phase shifts?

PubMed

Regente, J; de Zeeuw, J; Bes, F; Nowozin, C; Appelhoff, S; Wahnschaffe, A; Münch, M; Kunz, D

2017-05-01

In single night shifts, extending habitual wake episodes leads to sleep deprivation induced decrements of performance during the shift and re-adaptation effects the next day. We investigated whether short-wavelength depleted (=filtered) bright light (FBL) during a simulated night shift would counteract such effects. Twenty-four participants underwent a simulated night shift in dim light (DL) and in FBL. Reaction times, subjective sleepiness and salivary melatonin concentrations were assessed during both nights. Daytime sleep was recorded after both simulated night shifts. During FBL, we found no melatonin suppression compared to DL, but slightly faster reaction times in the second half of the night. Daytime sleep was not statistically different between both lighting conditions (n = 24) and there was no significant phase shift after FBL (n = 11). To conclude, our results showed positive effects from FBL during simulated single night shifts which need to be further tested with larger groups, in more applied studies and compared to standard lighting. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physical workload, trapezius muscle activity, and neck pain in nurses' night and day shifts: a physiological evaluation.

PubMed

Nicoletti, Corinne; Spengler, Christina M; Läubli, Thomas

2014-05-01

The purpose of this study was to compare physical workload, electromyography (EMG) of the trapezius muscle, neck pain and mental well-being at work between night and day shifts in twenty Swiss nurses. Work pulse (average increase of heart rate over resting heart rate) was lower during night (27 bpm) compared to day shifts (34 bpm; p < 0.01). Relative arm acceleration also indicated less physical activity during night (82% of average) compared to day shifts (110%; p < 0.01). Rest periods were significantly longer during night shifts. Trapezius muscle rest time was longer during night (13% of shift duration) than day shifts (7%; p < 0.01) and the 50th percentile of EMG activity was smaller (p = 0.02), indicating more opportunities for muscle relaxation during night shifts. Neck pain and mental well-being at work were similar between shifts. Subjective perception of burden was similar between shifts despite less physical burden at night, suggesting there are other contributing factors. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

A unique, fast-forwards rotating schedule with 12-h long shifts prevents chronic sleep debt.

PubMed

Fischer, Dorothee; Vetter, Céline; Oberlinner, Christoph; Wegener, Sven; Roenneberg, Till

2016-01-01

Sleep debt--together with circadian misalignment--is considered a central factor for adverse health outcomes associated with shift work. Here, we describe in detail sleep-wake behavior in a fast-forward rotating 12-h shift schedule, which involves at least 24 hours off after each shift and thus allows examining the role of immediate recovery after shift-specific sleep debt. Thirty-five participants at two chemical plants in Germany were chronotyped using the Munich ChronoType Questionnaire for Shift-Workers (MCTQ(Shift)) and wore actimeters throughout the two-week study period. From these actimetry recordings, we computed sleep and nap duration, social jetlag (a measure of circadian misalignment), and the daily timing of activity and sleep (center of gravity and mid-sleep, respectively). We observed that the long off-work periods between each shift create a fast alternation between shortened (mean ± standard deviation, 5h 17min ± 56min) and extended (8h 25min ± 72min) sleep episodes resulting in immanent reductions of sleep debt. Additionally, extensive napping of early chronotypes (up to 3 hours before the night shift) statistically compensated short sleep durations after the night shift. Partial rank correlations showed chronotype-dependent patterns of sleep and activity that were similar to those previously described in 8-h schedules; however, sleep before the day shift did not differ between chronotypes. Our findings indicate that schedules preventing a build-up of chronic sleep debt may reduce detrimental effects of shift work irrespective of shift duration. Prospective studies are needed to further elucidate the relationship between sleep, the circadian system, and health and safety hazards.

The impact of night-shift work on platelet function in healthy medical staff.

PubMed

Nakao, Tomoko; Yasumoto, Atsushi; Tokuoka, Suzumi; Kita, Yoshihiro; Kawahara, Takuya; Daimon, Masao; Yatomi, Yutaka

2018-04-18

Rotating shift work has been reported to increase the risk of cardiovascular diseases. Vascular endothelial dysfunction and platelet activation are among the leading causes of thrombus formation in patients with myocardial infarction or stroke. Endothelial function has been shown to be impaired immediately after night-shift work; however, it is not known whether platelets are also activated. The aim of this study was to investigate the acute impact of night-shift work on platelet function. This observational study included 11 healthy medical staff members (seven women, median age 32 years). We examined each subject's platelet aggregation rates and the serum concentrations of eicosanoid mediators after night-shift work and on day-shift work without preceding night-shift work (baseline). Platelet aggregation did not differ from baseline levels after night-shift work. However, serum cyclooxygenase (COX)-metabolized eicosanoid mediators, particularly thromboxane (Tx) B 2 (a stable metabolite of TxA 2 and the most important marker of platelet activation), were significantly higher after the night-shift than at baseline (median 65.3 vs 180.4 ng/ml). Although platelet aggregation did not increase, there was an increase in serum COX-metabolized eicosanoid mediators such as TxB 2 in healthy medical staff after night-shift work. This platelet hypersensitivity may be one of the mechanisms underlying the significant association between night-shift work and adverse cardiovascular outcomes.

Risk of injury after evening and night work - findings from the Danish Working Hour Database.

PubMed

Nielsen, Helena B; Larsen, Ann D; Dyreborg, Johnny; Hansen, Åse M; Pompeii, Lisa A; Conway, Sadie H; Hansen, Johnni; Kolstad, Henrik A; Nabe-Nielsen, Kirsten; Garde, Anne H

2018-05-08

Objectives Evening and night work have been associated with higher risk of injury than day work. However, previous findings may be affected by recall bias and unmeasured confounding from differences between day, evening and night workers. This study investigates whether evening and night work during the past week increases risk of injury when reducing recall bias and unmeasured confounding. Methods We linked daily working hours at the individual level of 69 200 employees (167 726 person years from 2008-2015), primarily working at hospitals to registry information on 11 834 injuries leading to emergency room visits or death. Analyses were conducted with Poisson regression models in the full population including permanent day, evening and night workers, and in two sub-populations of evening and night workers, with both day and evening or night work, respectively. Thus, the exchangeability between exposure and reference group was improved in the two sub-populations. Results Risk of injury was higher after a week with evening work [incidence rate ratio (IRR) 1.32, 95% confidence interval (CI) 1.26-1.37] and night work (IRR 1.33, 95% CI 1.25-1.41) compared with only day work. Similar, although attenuated, estimates were found for evening work among evening workers (IRR 1.18, 95% CI 1.12-1.25), and for night work among night workers (IRR 1.10, 95% CI 1.01-1.20). Conclusion There is an overall increased risk of injury after a week that has included evening or night work compared with only day work. Though attenuated, the higher risk remains after reducing unmeasured confounding.

Registrar sleep patterns and supervision during two different rosters in a tertiary Australasian intensive care unit.

PubMed

Poynter, Chris J; Garden, Alexander; Young, Paul J

2012-03-01

To compare registrar sleep and supervision hours before and after a change in roster to accommodate more senior registrar (SR) positions, and to identify risky patterns of sleep on night shifts. Prospective study of 21 registrars on two different roster templates from September 2010 to May 2011 in the intensive care unit of Wellington Regional Hospital, Wellington, New Zealand. Roster change from 13 registrars and one SR to 10 registrars and four SRs. Mean sleep and supervision hours by shift; episodes of sleep ≤ 5 hours, wakefulness ≥17 hours, sleep during shift, waking before 16:00 before night shifts. 990 sleep surveys were analysed. There was no significant difference between groups in mean sleep or supervision hours for any shift. Two hundred and thirty-six night shifts were analysed. Registrars slept ≤5 hours before 19/236 (8.1%) night shifts; had ≥17 hours wakefulness before 79/236 night shifts (33.5%); woke by 16:00 107/ 236 (45.3%) times; and slept during 86/236 (36.4%) night shifts. Registrars arrived at work having either woken before 16:00 or had ≤5 hours of sleep on 114/236 (48.3%) night shifts. Changing the registrar roster to meet the training demands of our senior trainees did not adversely affect registrar sleep or supervision. Registrars may be taking on unnecessary risk due to poor sleep hygiene around night shifts. We suggest sleep education and scheduled sleep time during night shifts.

What is the preferred number of consecutive night shifts? results from a crossover intervention study among police officers in Denmark.

PubMed

Nabe-Nielsen, Kirsten; Jensen, Marie Aarrebo; Hansen, Åse Marie; Kristiansen, Jesper; Garde, Anne Helene

2016-10-01

Among police officers in Denmark, we studied (i) how many consecutive night shifts participants preferred at baseline; (ii) preferences regarding three intervention conditions (two, four, and seven consecutive night shifts followed by the same number of days off/day shifts: '2 + 2', '4 + 4', '7 + 7') at follow-up; (iii) characteristics of participants preferring each of these intervention conditions. Questionnaire data from a crossover intervention study were used (baseline: n = 73; follow-up: n = 68). At baseline, 49% preferred four consecutive night shifts. At follow-up, 57% preferred '4 + 4', 26% preferred '2 + 2' and 26% preferred '7 + 7'. Participants, who preferred longer spells of night work experienced that night work was less demanding, found it easier to sleep at different times of the day, and were more frequently evening types compared with participants who preferred shorter spells of night work. The participants' preferences are likely to be influenced by their previous shift work experience. Practitioner Summary: We investigated police officers' preferences regarding the number of consecutive night shifts. The majority preferred four consecutive night shifts. Those who preferred the longer spells of night work found night work less demanding, found it easier to sleep at different times of the day, and were more frequently evening types.

Scheduled evening sleep and enhanced lighting improve adaptation to night shift work in older adults.

PubMed

Chinoy, Evan D; Harris, Michael P; Kim, Min Ju; Wang, Wei; Duffy, Jeanne F

2016-12-01

We tested whether a sleep and circadian-based treatment shown to improve circadian adaptation to night shifts and attenuate negative effects on alertness, performance and sleep in young adults would also be effective in older adults. We assessed subjective alertness, sustained attention (psychomotor vigilance task, PVT), sleep duration (actigraphy) and circadian timing (salivary dim-light melatonin onset, DLMO) in 18 older adults (57.2±3.8 years; mean±SD) in a simulated shift work protocol. 4 day shifts were followed by 3 night shifts in the laboratory. Participants slept at home and were randomised to either the treatment group (scheduled evening sleep and enhanced lighting during the latter half of night shifts) or control group (ad-lib sleep and typical lighting during night shifts). Compared with day shifts, alertness and sustained attention declined on the first night shift in both groups, and was worse in the latter half of the night shifts. Alertness and attention improved on nights 2 and 3 for the treatment group but remained lower for the control group. Sleep duration in the treatment group remained similar to baseline (6-7 hours) following night shifts, but was shorter (3-5 hours) following night shifts in the control group. Treatment group circadian timing advanced by 169.3±16.1 min (mean±SEM) but did not shift (-9.7±9.9 min) in the control group. The combined treatment of scheduled evening sleep and enhanced lighting increased sleep duration and partially aligned circadian phase with sleep and work timing, resulting in improved night shift alertness and performance. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Fluctuations in heart rate variability of health care workers during four consecutive extended work shifts and recovery during rest and sleep.

PubMed

Goffeng, Elisabeth M; Nordby, Karl-Christian; Tarvainen, Mika P; Järvelin-Pasanen, Susanna; Wagstaff, Anthony; Goffeng, Lars Ole; Bugge, Merete; Skare, Øivind; Sigstad Lie, Jenny-Anne

2018-04-07

The aim of this study was to investigate fluctuations in heart rate variability (HRV), which reflect autonomic nervous system (ANS) function and potential psychological and physical strain, among 24 health care workers during work and sleep during four consecutive extended work shifts. Data included 24/36/12 h of HRV measurements, two logbooks, and a questionnaire. A cross-shift/cross-week design was applied. HRV was measured during work, leisure time, and sleep. The HRV data included time-domain [mean RR, SD of normal to normal R-R intervals (SDNN), and root mean square of the successive differences (RMSSD)] and frequency-domain [low frequency (LF)/high frequency (HF) ratio] parameters. HRV parameters revealed significant differences among work, leisure time, and sleep. Mean RR, RMSSD, and SDNN values were lower and the LF/HF ratio was higher on the first versus last day of the work period; however, the differences were most prominent in the morning hours. The results indicate higher levels of cardiovascular stress on the first versus fourth day of the working period, and measurements at night indicate a satisfactory recovery from the extended shifts.

Shift Work and Endocrine Disorders

PubMed Central

Ulhôa, M. A.; Marqueze, E. C.; Burgos, L. G. A.; Moreno, C. R. C.

2015-01-01

The objective of this review was to investigate the impact of shift and night work on metabolic processes and the role of alterations in the sleep-wake cycle and feeding times and environmental changes in the occurrence of metabolic disorders. The literature review was performed by searching three electronic databases for relevant studies published in the last 10 years. The methodological quality of each study was assessed, and best-evidence synthesis was applied to draw conclusions. The literature has shown changes in concentrations of melatonin, cortisol, ghrelin, and leptin among shift workers. Melatonin has been implicated for its role in the synthesis and action of insulin. The action of this hormone also regulates the expression of transporter glucose type 4 or triggers phosphorylation of the insulin receptor. Therefore, a reduction in melatonin can be associated with an increase in insulin resistance and a propensity for the development of diabetes. Moreover, shift work can negatively affect sleep and contribute to sedentarism, unhealthy eating habits, and stress. Recent studies on metabolic processes have increasingly revealed their complexity. Physiological changes induced in workers who invert their activity-rest cycle to fulfill work hours include disruptions in metabolic processes. PMID:25892993

Socioeconomic status, occupational characteristics, and sleep duration in African/Caribbean immigrants and US White health care workers.

PubMed

Ertel, Karen A; Berkman, Lisa F; Buxton, Orfeu M

2011-04-01

o advance our understanding of the interplay of socioeconomic factors, occupational exposures, and race/ethnicity as they relate to sleep duration. We hypothesize that non Hispanic African/Caribbean immigrant employees in long term health care have shorter sleep duration than non Hispanic white employees, and that low education, low income, and occupational exposures including night work and job strain account for some of the African/Caribbean immigrant-white difference in sleep duration. Cross sectional Four extended care facilities in Massachusetts, United States 340 employees in extended care facilities Sleep duration was assessed with wrist actigraphy for a mean of 6.3 days. In multivariable regression modeling controlling for gender and age, African/Caribbean immigrants slept 64.4 fewer minutes (95% CI: -81.0, -47.9) per night than white participants; additional control for education and income reduced the racial gap to 50.9 minutes (-69.2, -32.5); additional control for the occupational factors of hours worked per week and working the night shift reduced the racial gap to 37.7 minutes (-57.8, -17.6). his study provides support for the hypothesis that socioeconomic and occupational characteristics explain some of the African/ Caribbean immigrant-white difference in sleep duration in the United States, especially among health care workers.

A Pilot Study to Examine the Relationship Between Napping and Fatigue in Nurses Practicing on the Night Shift.

PubMed

Neville, Kathleen; Velmer, Gillian; Brown, Shari; Robol, Nancy

2017-11-01

The aim of this study is to explore the relationship of night-shift napping on fatigue. Nurses' fatigue, especially at night, interferes with quality of life and job performance and impacts safety and health. Night-shift nurses completed the Brief Fatigue Inventory and a demographic information sheet to determine differences in fatigue between nurses who napped during their night shift as compared with nurses who did not nap. No statistically significant differences in global fatigue were found; differences in rotating shift, age, and, gender were identified. Rotating shifts, a 2nd job, and caring for family predicted fatigue. Based on this pilot study, further investigations of fatigue among night-shift nurses are needed as well as evidence-based support to promote sleep.

Work ability of health care shift workers: What matters?

PubMed

Fischer, Frida Marina; Borges, Flavio Notarnicola da Silva; Rotenberg, Lucia; Latorre, Maria do Rosario Dias de Oliveira; Soares, Nilson Santos; Rosa, Patricia Lima Ferreira Santa; Teixeira, Liliane Reis; Nagai, Roberta; Steluti, Josiane; Landsbergis, Paul

2006-01-01

This paper aims at identifying variables associated with inadequate work ability among nursing personnel at a public hospital, considering factors related to socio-demographic, lifestyles, working conditions, and health outcomes. A cross-sectional study was conducted in a university hospital in São Paulo, Brazil, as part of a larger research study on tolerance to 12 h night work. Nursing staff included registered nurses, nurse technicians, and nurse aides; in total, there were 996 healthcare workers (878 female; 118 male) at the time of the study. Some 696 workers (69.9%) of the population agreed to participate. Data collection (October 2004-July 2005) was based on a comprehensive questionnaire about living and working conditions (including incivility at work, work demands, work control, and support), mental and physical health symptoms (fatigue and sleep problems), and work ability. This report presents analyses of the adapted Brazilian version of the Work Ability Index (WAI) and associated variables. The study population worked one of the following shift schedules at this hospital: 12 h nights followed by 36 h off or 9 h or 6 h day (morning or afternoon) shifts. The mean age of the respondents was 34.9 (S.D.+/-10.4) years of age; 31.5% of the participants held two jobs. Statistical analyses using a hierarchical multiple logistic regression model were performed to evaluate the factors associated with inadequate (moderate and low scores) of the WAI. The significantly associated factors were socio-demographic (income responsibility, sole breadwinner, raising kids, age group), working conditions (thermal discomfort, organization of the workplace, and verbal abuse), and health outcomes (high body mass index, obesity, sleep problems, and fatigue). In spite of limitations of the study design, results indicate that the nursing profession is associated with stressful working conditions, contributing to inadequate WAI. This is in addition to bad living conditions and precarious work. Intervention measures, either at the workplace or at individual levels, are necessary to prevent a decrease in work ability, even in this quite young working population.

Work-related risk factors for workplace violence among Korean employees.

PubMed

Lee, Hye-Eun; Kim, Hyoung-Ryoul; Park, Jung Sun

2014-01-01

The aim of this study was to identify work-related risk factors for workplace violence in a representative sample of Korean employees. We analyzed the associations between work-related factors and workplace violence in 29,171 employees using data from the 2011 Korean Working Conditions Survey. The survey included questions about verbal abuse, unwanted sexual attention, threats and behavior that humiliated the victim, physical violence, bullying/harassment and sexual harassment, and a respondent who answered yes to any of these 6 items was considered a victim of workplace violence. The prevalences of verbal abuse, unwanted sexual attention and threats/behavior that humiliated victims in the month preceding the study were 4.8, 1.0 and 1.5%, respectively. The prevalences of physical violence, bullying/harassment and sexual harassment in the year preceding the study were 0.7, 0.3 and 0.4%, respectively. Service workers had higher prevalences of overall workplace violence. Non-regular workers (OR=2.38, 95% CI=2.01-2.84), working more than 60 hours per week as opposed to 40-48 hours per week (OR=1.83, 95% CI=1.45-2.31) and night shift work (OR=1.88, 95% CI=1.54-2.30) were significant risk factors associated with workplace violence. Long working hours, job insecurity and night shift work were associated with a significant increase in workplace violence among Korean employees.

Regulation of L1 expression and retrotransposition by melatonin and its receptor: implications for cancer risk associated with light exposure at night

PubMed Central

deHaro, Dawn; Kines, Kristine J.; Sokolowski, Mark; Dauchy, Robert T.; Streva, Vincent A.; Hill, Steven M.; Hanifin, John P.; Brainard, George C.; Blask, David E.; Belancio, Victoria P.

2014-01-01

Expression of long interspersed element-1 (L1) is upregulated in many human malignancies. L1 can introduce genomic instability via insertional mutagenesis and DNA double-strand breaks, both of which may promote cancer. Light exposure at night, a recently recognized carcinogen, is associated with an increased risk of cancer in shift workers. We report that melatonin receptor 1 inhibits mobilization of L1 in cultured cells through downregulation of L1 mRNA and ORF1 protein. The addition of melatonin receptor antagonists abolishes the MT1 effect on retrotransposition in a dose-dependent manner. Furthermore, melatonin-rich, but not melatonin-poor, human blood collected at different times during the circadian cycle suppresses endogenous L1 mRNA during in situ perfusion of tissue-isolated xenografts of human cancer. Supplementation of human blood with exogenous melatonin or melatonin receptor antagonist during the in situ perfusion establishes a receptor-mediated action of melatonin on L1 expression. Combined tissue culture and in vivo data support that environmental light exposure of the host regulates expression of L1 elements in tumors. Our data imply that light-induced suppression of melatonin production in shift workers may increase L1-induced genomic instability in their genomes and suggest a possible connection between L1 activity and increased incidence of cancer associated with circadian disruption. PMID:24914052

Nurses' sleep quality, work environment and quality of care in the Spanish National Health System: observational study among different shifts.

PubMed

Gómez-García, Teresa; Ruzafa-Martínez, María; Fuentelsaz-Gallego, Carmen; Madrid, Juan Antonio; Rol, Maria Angeles; Martínez-Madrid, María José; Moreno-Casbas, Teresa

2016-08-05

The main objective of this study was to determine the relationship between the characteristics of nurses' work environments in hospitals in the Spanish National Health System (SNHS) with nurse reported quality of care, and how care was provided by using different shifts schemes. The study also examined the relationship between job satisfaction, burnout, sleep quality and daytime drowsiness of nurses and shift work. This was a multicentre, observational, descriptive, cross-sectional study, centred on a self-administered questionnaire. The study was conducted in seven SNHS hospitals of different sizes. We recruited 635 registered nurses who worked on day, night and rotational shifts on surgical, medical and critical care units. Their average age was 41.1 years, their average work experience was 16.4 years and 90% worked full time. A descriptive and bivariate analysis was carried out to study the relationship between work environment, quality and safety care, and sleep quality of nurses working different shift patterns. 65.4% (410) of nurses worked on a rotating shift. The Practice Environment Scale of the Nursing Work Index classification ranked 20% (95) as favourable, showing differences in nurse manager ability, leadership and support between shifts (p=0.003). 46.6% (286) were sure that patients could manage their self-care after discharge, but there were differences between shifts (p=0.035). 33.1% (201) agreed with information being lost in the shift change, showing differences between shifts (p=0.002). The Pittsburgh Sleep Quality Index reflected an average of 6.8 (SD 3.39), with differences between shifts (p=0.017). Nursing requires shift work, and the results showed that the rotating shift was the most common. Rotating shift nurses reported worse perception in organisational and work environmental factors. Rotating and night shift nurses were less confident about patients' competence of self-care after discharge. The most common nursing care omissions reported were related to nursing care plans. For the Global Sleep Quality score, difference were found between day and night shift workers. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Recovery and well-being among Helicopter Emergency Medical Service (HEMS) pilots.

PubMed

Radstaak, Mirjam; Geurts, Sabine A E; Beckers, Debby G J; Brosschot, Jos F; Kompier, Michiel A J

2014-07-01

This study investigated the effects of a compressed working week with high cognitive and emotional work demands within the population of Dutch Helicopter Emergency Medical Service (HEMS) pilots. Work stressors were measured and levels of well-being were examined before, during and after a series of day and night shifts. Results revealed that (i) the start of a series of day shifts was more taxing for well-being than the start of a series of night shifts, (ii) there were no differences in the decrease in well-being during day and night shifts, (iii) distress during shifts was more strongly related to a decrease in well-being during night than during day shifts and (iv) it took HEMS pilots more time to recover from a series of night shifts than from a series of day shifts. It is concluded that HEMS pilots should not start earlier during day shifts, nor have longer series of night shifts. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Students' educational experiences and interaction with residents on night shifts.

PubMed

Schiller, Jocelyn; Sokoloff, Max; Tendhar, Chosang; Schmidt, John; Christner, Jennifer

2017-08-01

The purpose of this mixed-methods study was to investigate whether increased night shifts for students on paediatric rotations had any negative impact on their overall quality of educational experiences in light of the implementation of duty-hour restrictions. Both quantitative and qualitative data were collected from 30 students on paediatric rotations during the academic year 2011/12. Students completed two questionnaires, one in response to their experiences during the day shifts and another in response to their experiences during the night shifts. Only 25 cases were retained for the final analyses. The non-parametric Wilcoxon signed-rank test was used to analyse the quantitative data, and constant comparative thematic analyses, as described by Creswell, were used to analyse the qualitative data. [Do] increased nights shifts for students … [have] any negative impact on their overall quality of educational experiences[?] RESULTS: The results indicated that students' perceived quality of experiences during the night shifts was greater, compared with their day shifts. Students reported having more time to socialise during the night shifts. They further reported that informal ways of learning, such as impromptu teaching and spontaneous discussions on clinical problems, were more beneficial, and these often occurred in abundance during the night shifts as opposed to the scheduled didactic teaching sessions that occur during the day shifts. This study documented many unanticipated benefits of night shifts. The feeling of cohesiveness of the night team deserves further exploration, as this can be linked to better performance outcomes. More consideration should be given to implementing night shifts as a regular feature of clerkships. © 2016 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

Changes in the diurnal rhythms of cortisol, melatonin, and testosterone after 2, 4, and 7 consecutive night shifts in male police officers.

PubMed

Jensen, Marie Aarrebo; Hansen, Åse Marie; Kristiansen, Jesper; Nabe-Nielsen, Kirsten; Garde, Anne Helene

2016-08-11

Night work is associated with a large range of acute health problems and possibly also health consequences in the long run. Yet, only very few field studies specifically investigate the effects of consecutive night shift on key physiological regulatory systems. In this field study, we investigated the effects of consecutive night shifts on three hormones, melatonin, cortisol, and testosterone, among police officers at work. More specifically, the aim was to investigate how the diurnal rhythms of melatonin, cortisol, and testosterone responded to two, four, and seven consecutive night shifts and a corresponding number of days for recovery. The study was part of the "In the Middle of the Night" project and included 73 male police officers from five different police districts. The participants were exposed to three intervention conditions: "2+2": two consecutive night shifts followed by two consecutive day recovery days; "4+4": four consecutive night shifts followed by four consecutive recovery days; "7+7": seven consecutive night shifts followed by seven consecutive recovery days. On the last day with night shift and the last recovery day in each intervention, the participants collected saliva samples every 4th hour when awake. The diurnal rhythms of melatonin, cortisol, and testosterone were all affected differently by an increasing number of consecutive night shifts: the amplitude of the melatonin rhythm was suppressed by 4.9% per day (95% CI 1.4-8.2% per day; p = 0.006). The diurnal rhythm of cortisol phase was delayed with an increasing number of night shifts by 33 min/day (95% CI 18-48 min per day; p ≤ 0.001), but did not show any changes in amplitude. For the diurnal rhythm of testosterone, there was no effect of the number of consecutive night shifts and the diurnal rhythm completely followed the sleep/wake cycle. We found that there were no differences in the rhythms of melatonin, cortisol, and testosterone after 2, 4, and 7 recovery days, respectively. In conclusion, we found signs of desynchronization in terms of suppressed amplitude of melatonin and phase delay of salivary cortisol as a consequence of the increasing number of consecutive night shifts among police officers at work. Lack of synchronization has been suggested as a possible mechanism linking night work to disease, but this remains to be determined.

Total and cause-specific mortality of U.S. nurses working rotating night shifts.

PubMed

Gu, Fangyi; Han, Jiali; Laden, Francine; Pan, An; Caporaso, Neil E; Stampfer, Meir J; Kawachi, Ichiro; Rexrode, Kathryn M; Willett, Walter C; Hankinson, Susan E; Speizer, Frank E; Schernhammer, Eva S

2015-03-01

Rotating night shift work imposes circadian strain and is linked to the risk of several chronic diseases. To examine associations between rotating night shift work and all-cause; cardiovascular disease (CVD); and cancer mortality in a prospective cohort study of 74,862 registered U.S. nurses from the Nurses' Health Study. Lifetime rotating night shift work (defined as ≥3 nights/month) information was collected in 1988. During 22 years (1988-2010) of follow-up, 14,181 deaths were documented, including 3,062 CVD and 5,413 cancer deaths. Cox proportional hazards models estimated multivariable-adjusted hazard ratios (HRs) and 95% CIs. All-cause and CVD mortality were significantly increased among women with ≥5 years of rotating night shift work, compared to women who never worked night shifts. Specifically, for women with 6-14 and ≥15 years of rotating night shift work, the HRs were 1.11 (95% CI=1.06, 1.17) and 1.11 (95% CI=1.05, 1.18) for all-cause mortality and 1.19 (95% CI=1.07, 1.33) and 1.23 (95% CI=1.09, 1.38) for CVD mortality. There was no significant association between rotating night shift work and all-cancer mortality (HR≥15years=1.08, 95% CI=0.98, 1.19) or mortality of any individual cancer, with the exception of lung cancer (HR≥15years=1.25, 95% CI=1.04, 1.51). Women working rotating night shifts for ≥5 years have a modest increase in all-cause and CVD mortality; those working ≥15 years of rotating night shift work have a modest increase in lung cancer mortality. These results add to prior evidence of a potentially detrimental effect of rotating night shift work on health and longevity. Copyright © 2015 American Journal of Preventive Medicine. All rights reserved.

Total and Cause-Specific Mortality of U.S. Nurses Working Rotating Night Shifts

PubMed Central

Gu, Fangyi; Han, Jiali; Laden, Francine; Pan, An; Caporaso, Neil E.; Stampfer, Meir J.; Kawachi, Ichiro; Rexrode, Kathryn M.; Willett, Walter C.; Hankinson, Susan E.; Speizer, Frank; Schernhammer, Eva S.

2014-01-01

Background Rotating night shift work imposes circadian strain and is linked to the risk of several chronic diseases. Purpose To examine associations between rotating night shift work and all-cause, cardiovascular disease (CVD), and cancer mortality in a prospective cohort study of 74,862 registered U.S. nurses from the Nurses’ Health Study. Methods Lifetime rotating night shift work (defined as ≥3 nights/month) information was collected in 1988. During 22 years (1988–2010) of follow-up, 14,181 deaths were documented, including 3,062 CVD and 5,413 cancer deaths. Cox proportional hazards models (2013) estimated multivariable-adjusted hazard ratios (HRs) and 95% CIs. Results All-cause and CVD mortality were significantly increased among women with ≥5 years of rotating night shift work, compared to women who never worked night shifts. Specifically, for women with 6–14 and ≥15 years of rotating night shift work, the HRs were 1.11 (95% CI=1.06, 1.17) and 1.11 (95% CI=1.05, 1.18) for all-cause mortality and 1.19 (95% CI=1.07, 1.33) and 1.23 (95% CI=1.09, 1.38) for CVD mortality. There was no association between rotating night shift work and all-cancer mortality (HR≥15years=1.08, 95% CI=0.89, 1.19) or any other cancer, with the exception of lung cancer (HR≥15years=1.25, 95% CI=1.04, 1.51). Conclusions Women working rotating night shifts for ≥5 five years have a modest increase in all-cause and CVD mortality; those working ≥15 years of rotating night shift work have a modest increase in lung cancer mortality. These results add to prior evidence of a potentially detrimental effect of rotating night shift work on health and longevity. PMID:25576495

NIGHT SHIFT WORK AND FRACTURE RISK: THE NURSES’ HEALTH STUDY

PubMed Central

Feskanich, Diane; Hankinson, Susan E.; Schernhammer, Eva S.

2009-01-01

Summary Night shift work suppresses melatonin production and has been associated with an increased risk of major diseases including hormonally related tumors. Experimental evidence suggests that light at night acts through endocrine disruption, likely mediated by melatonin. To date, no observational study has addressed the effect of night work on osteoporotic fractures, another condition highly sensitive to sex steroid exposure. Our study, to our knowledge the first to address this question, supports the hypothesis that night shift work may negatively affect bone health, adding to the growing list of ailments that have been associated with shift work. Introduction We evaluated the association between night shift work and fractures at the hip and wrist in postmenopausal nurses. Methods The study population was drawn from Nurses’ Health Study participants who were working full or part time in nursing in 1988 and had reported their total number of years of rotating night shift work. Through 2000, 1,223 incident wrist and hip fractures involving low or moderate trauma were identified among 38,062 postmenopausal women. We calculated multivariate relative risks (RR) of fracture over varying lengths of follow-up in relation to years of night shift work. Results Compared with women who never worked night shifts, 20+ years of night shift work was associated with a significantly increased risk of wrist and hip fractures over eight years of follow-up (RR = 1.37, 95% confidence interval [CI], 1.04–1.80). This risk was strongest among women with a lower BMI (<24) who never used hormone replacement therapy (RR = 2.36; 95% CI, 1.33–4.20). The elevated risk was no longer apparent with twelve years of follow-up after the baseline single assessment of night shift work. Conclusions Long durations of rotating night shift work may contribute to risk of hip and wrist fractures, although the potential for unexplained confounding cannot be ruled out. PMID:18766292

Association between night work and cardiovascular diseases: analysis of the 3rd Korean working conditions survey.

PubMed

Park, Sungjin; Nam, Juhyun; Lee, Jong-Ku; Oh, Sung-Soo; Kang, Hee-Tae; Koh, Sang-Baek

2015-01-01

This study was conducted to investigate the relationship between night work and cardiovascular diseases among wage workers in Korea. The study was based on the 3rd Korean Working Conditions Survey (KWCS; 2011). This study included 29,711 wage workers. We used the chi-squared test and logistic regression to examine the association between cardiovascular diseases and night work and cumulative night work. Among all of the paid workers, 12.5% reported doing night work ≥ 1 day per month. Night work was significantly associated with an increased risk of cardiovascular diseases (odds ratio [OR] 1.58, 95% confidence interval [CI] 1.11-2.25). Also, compared to the group that did not do night works, the group with higher cumulative night work demonstrated an increased risk for cardiovascular diseases (OR 1.81, 95% CI 1.19-2.74). This study suggests that night work is significantly associated with cardiovascular diseases.

Circadian gene expression in peripheral blood leukocytes of rotating night shift nurses.

PubMed

Reszka, Edyta; Peplonska, Beata; Wieczorek, Edyta; Sobala, Wojciech; Bukowska, Agnieszka; Gromadzinska, Jolanta; Lie, Jenny-Anne; Kjuus, Helge; Wasowicz, Wojciech

2013-03-01

It has been hypothesized that the underlying mechanism of elevated breast cancer risk among long-term, night-working women involves circadian genes expression alteration caused by exposure to light at night and/or irregular work hours. The aim of the present study was to determine the effect of rotating night shift work on expression of selected core circadian genes. The cross-sectional study was conducted on 184 matched nurses and midwives, who currently work either day or rotating night shifts, to determine the effect of irregular work at night on circadian gene expression in peripheral blood leukocytes. Transcript levels of BMAL1, CLOCK, CRY1, CRY2, PER1, PER2, and PER3 were determined by means of quantitative real-time polymerase chain reaction (PCR). After adjusting for hour of blood collection, there were no statistically significant changes of investigated circadian genes among nurses and midwives currently working rotating night shifts compared to nurses working day shifts. The highest expression of PER1 messenger ribonucleic acid (mRNA) was observed for women currently working shifts who had worked >15 years in rotating night shift work. PER1 gene expression was associated with the lifetime duration of rotating night shift work among women currently working night shifts (P=0.04). PER1 and PER3 transcript levels in blood leukocytes were significantly down-regulated in the later versus early hours of the morning between 06.00-10.00 hours (β-coefficient -0.226, P=0.001 and β-coefficient -0.181, P<0.0001, respectively). These results suggest that current rotating night shift work does not affect circadian gene expression in human circulating leukocytes. In analysis of the peripheral clock in human studies, the hour of blood collection should be precisely specified.

The effect of the number of consecutive night shifts on diurnal rhythms in cortisol, melatonin and heart rate variability (HRV): a systematic review of field studies.

PubMed

Jensen, Marie Aarrebo; Garde, Anne Helene; Kristiansen, Jesper; Nabe-Nielsen, Kirsten; Hansen, Åse Marie

2016-05-01

The purpose of this review is to summarize the current knowledge from field studies on how many consecutive night shifts are required for adaptation of diurnal rhythms in cortisol, melatonin and heart rate variability (HRV) to night work. A systematic search of the databases PubMed and Web of Science resulted in 18 studies selected for review. Cortisol was measured in five studies, melatonin in 11 studies and HRV in four studies. Diurnal rhythms were assessed by use of several different measures based on three to eight samples per day for cortisol and melatonin and 24-h recordings for HRV. Most of the studies in the review were small studies with less than 30 participants, and most studies evaluated diurnal rhythms after only two consecutive night shifts whereas only six studies used seven or more consecutive night shifts. The majority of studies found that adaptation to night work had not occurred after two consecutive night shifts, whereas a small number found evidence for full adaptation after seven consecutive night shifts based on diurnal rhythms in cortisol and melatonin. There are methodological differences in the field studies analyzing diurnal rhythms and large diversity in the occupational fields studied. Nevertheless, we conclude that diurnal rhythms in cortisol, melatonin and HRV are not adapted to night work after 1-3 consecutive night shifts. Studies are needed to establish how many consecutive night shifts are needed for full adaptation of diurnal rhythms to night work.

Physical occupational exposures and health expectancies in a French occupational cohort.

PubMed

Platts, Loretta G; Head, Jenny; Stenholm, Sari; Singh Chungkham, Holendro; Goldberg, Marcel; Zins, Marie

2017-03-01

To examine the relationships of strenuous and hazardous working conditions and rotating shifts that involve night working with life expectancy in good perceived health and life expectancy without chronic disease. The sample contained male gas and electricity workers from the French GAZEL cohort (n=13 393). Six measures of physical working conditions were examined: Self-reports from 1989 and 1990 of ergonomic strain, physical danger, rotating shifts that involve night working and perceived physical strain; company records of workplace injuries and a job-exposure matrix of chemical exposures. Partial healthy life expectancies (age 50-75) relating to (1) self-rated health and (2) chronic health conditions, obtained from annual questionnaires (1989-2014) and company records, were estimated using multistate life tables. The analyses were adjusted for social class and occupational grade. Participants with physically strenuous jobs and who had experienced industrial injuries had shorter partial life expectancy. More physically demanding and dangerous work was associated with fewer years of life spent in good self-rated health and without chronic conditions, with the exception of shift work including nights, where the gradient was reversed. Strenuous and hazardous work may contribute to lost years of good health in later life, which has implications for individuals' quality of life as well as healthcare use and labour market participation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Night Shift Work and Breast Cancer Incidence: Three Prospective Studies and Meta-analysis of Published Studies

PubMed Central

Balkwill, Angela; Fensom, Georgina K.; Appleby, Paul N.; Reeves, Gillian K.; Wang, Xiao-Si; Roddam, Andrew W.; Gathani, Toral; Peto, Richard; Green, Jane; Key, Timothy J.; Beral, Valerie

2016-01-01

Background: It has been proposed that night shift work could increase breast cancer incidence. A 2007 World Health Organization review concluded, mainly from animal evidence, that shift work involving circadian disruption is probably carcinogenic to humans. We therefore aimed to generate prospective epidemiological evidence on night shift work and breast cancer incidence. Methods: Overall, 522 246 Million Women Study, 22 559 EPIC-Oxford, and 251 045 UK Biobank participants answered questions on shift work and were followed for incident cancer. Cox regression yielded multivariable-adjusted breast cancer incidence rate ratios (RRs) and 95% confidence intervals (CIs) for night shift work vs no night shift work, and likelihood ratio tests for interaction were used to assess heterogeneity. Our meta-analyses combined these and relative risks from the seven previously published prospective studies (1.4 million women in total), using inverse-variance weighted averages of the study-specific log RRs. Results: In the Million Women Study, EPIC-Oxford, and UK Biobank, respectively, 673, 28, and 67 women who reported night shift work developed breast cancer, and the RRs for any vs no night shift work were 1.00 (95% CI = 0.92 to 1.08), 1.07 (95% CI = 0.71 to 1.62), and 0.78 (95% CI = 0.61 to 1.00). In the Million Women Study, the RR for 20 or more years of night shift work was 1.00 (95% CI = 0.81 to 1.23), with no statistically significant heterogeneity by sleep patterns or breast cancer risk factors. Our meta-analysis of all 10 prospective studies included 4660 breast cancers in women reporting night shift work; compared with other women, the combined relative risks were 0.99 (95% CI = 0.95 to 1.03) for any night shift work, 1.01 (95% CI = 0.93 to 1.10) for 20 or more years of night shift work, and 1.00 (95% CI = 0.87 to 1.14) for 30 or more years. Conclusions: The totality of the prospective evidence shows that night shift work, including long-term shift work, has little or no effect on breast cancer incidence. PMID:27758828

Night Shift Work and Breast Cancer Incidence: Three Prospective Studies and Meta-analysis of Published Studies.

PubMed

Travis, Ruth C; Balkwill, Angela; Fensom, Georgina K; Appleby, Paul N; Reeves, Gillian K; Wang, Xiao-Si; Roddam, Andrew W; Gathani, Toral; Peto, Richard; Green, Jane; Key, Timothy J; Beral, Valerie

2016-12-01

It has been proposed that night shift work could increase breast cancer incidence. A 2007 World Health Organization review concluded, mainly from animal evidence, that shift work involving circadian disruption is probably carcinogenic to humans. We therefore aimed to generate prospective epidemiological evidence on night shift work and breast cancer incidence. Overall, 522 246 Million Women Study, 22 559 EPIC-Oxford, and 251 045 UK Biobank participants answered questions on shift work and were followed for incident cancer. Cox regression yielded multivariable-adjusted breast cancer incidence rate ratios (RRs) and 95% confidence intervals (CIs) for night shift work vs no night shift work, and likelihood ratio tests for interaction were used to assess heterogeneity. Our meta-analyses combined these and relative risks from the seven previously published prospective studies (1.4 million women in total), using inverse-variance weighted averages of the study-specific log RRs. In the Million Women Study, EPIC-Oxford, and UK Biobank, respectively, 673, 28, and 67 women who reported night shift work developed breast cancer, and the RRs for any vs no night shift work were 1.00 (95% CI = 0.92 to 1.08), 1.07 (95% CI = 0.71 to 1.62), and 0.78 (95% CI = 0.61 to 1.00). In the Million Women Study, the RR for 20 or more years of night shift work was 1.00 (95% CI = 0.81 to 1.23), with no statistically significant heterogeneity by sleep patterns or breast cancer risk factors. Our meta-analysis of all 10 prospective studies included 4660 breast cancers in women reporting night shift work; compared with other women, the combined relative risks were 0.99 (95% CI = 0.95 to 1.03) for any night shift work, 1.01 (95% CI = 0.93 to 1.10) for 20 or more years of night shift work, and 1.00 (95% CI = 0.87 to 1.14) for 30 or more years. The totality of the prospective evidence shows that night shift work, including long-term shift work, has little or no effect on breast cancer incidence. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Dim light at night: physiological effects and ecological consequences for infectious disease.

PubMed

Kernbach, Meredith E; Hall, Richard J; Burkett-Cadena, Nathan; Unnasch, Thomas R; Martin, Lynn B

2018-06-23

Light pollution has emerged as a pervasive component of land development over the past century. Several detrimental impacts of this anthropogenic influence have been identified in night shift workers, laboratory rodents, and a plethora of wildlife species. Circadian, or daily, patterns are interrupted by the presence of light at night and have the capacity to alter rhythmic physiological or behavioral characteristics. Indeed, biorhythm disruption can lead to metabolic, reproductive, and immunological dysfunction depending on the intensity, timing, duration and wavelength of light exposure. Light pollution, in many forms and by many pathways, is thus apt to affect the nature of host-pathogen interactions. However, no research has yet investigated this possibility. The goal of this manuscript is to outline how dim light at night (dLAN), a relevant and common form of light pollution, may affect disease dynamics by interrupting circadian rhythms and regulation of immune responses as well as opportunities for host-parasite interactions and subsequent transmission risk including spillover into humans. We close by proposing some promising interventions including alternative lighting methods or vector control efforts.

Socioeconomic Status, Occupational Characteristics, and Sleep Duration in African/Caribbean Immigrants and US White Health Care Workers

PubMed Central

Ertel, Karen A.; Berkman, Lisa F.; Buxton, Orfeu M.

2011-01-01

Study Objectives: o advance our understanding of the interplay of socioeconomic factors, occupational exposures, and race/ethnicity as they relate to sleep duration. We hypothesize that non Hispanic African/Caribbean immigrant employees in long term health care have shorter sleep duration than non Hispanic white employees, and that low education, low income, and occupational exposures including night work and job strain account for some of the African/Caribbean immigrant–white difference in sleep duration. Design: Cross sectional Setting: Four extended care facilities in Massachusetts, United States Participants: 340 employees in extended care facilities Measurements and Results: Sleep duration was assessed with wrist actigraphy for a mean of 6.3 days. In multivariable regression modeling controlling for gender and age, African/Caribbean immigrants slept 64.4 fewer minutes (95% CI: −81.0, −47.9) per night than white participants; additional control for education and income reduced the racial gap to 50.9 minutes (−69.2, −32.5); additional control for the occupational factors of hours worked per week and working the night shift reduced the racial gap to 37.7 minutes (−57.8, −17.6). Conclusions: his study provides support for the hypothesis that socioeconomic and occupational characteristics explain some of the African/ Caribbean immigrant–white difference in sleep duration in the United States, especially among health care workers. Citation: Ertel KA; Berkman LF; Buxton OM. Socioeconomic status, occupational characteristics, and sleep duration in African/Caribbean immi grants and US white health care workers. SLEEP 2011; 34(4):509-518. PMID:21461330

Skills training after night shift work enables acquisition of endovascular technical skills on a virtual reality simulator.

PubMed

Naughton, Peter A; Aggarwal, Rajesh; Wang, Tim T; Van Herzeele, Isabelle; Keeling, Aoife N; Darzi, Ara W; Cheshire, Nicholas J W

2011-03-01

Adoption of residents' working time restrictions potentially undermines surgical training by reduction of operating room exposure. Simulation has been proposed as a way to acquire necessary skills in a laboratory environment but remains difficult to incorporate into training schedules. This study assessed whether residents working successive nights could acquire endovascular skills similar to colleagues working day shifts. This prospective observational cohort study recruited 20 junior residents, divided into day shift and night shift groups by their respective call schedule. After initial cognitive skills training, a validated renal artery stent module on an endovascular simulator was completed over a series of seven sequential shifts during 1 week. The primary outcome measure was serial technical skill assessments. Secondary measures comprised assessments of activity, cognitive performance, introspective fatigue, quality, and quantity of preceding sleep. Both groups demonstrated significant learning curves for total time at the first session median vs seventh session median (181 vs 564 seconds [P < .001]; night, 1399 vs 572 [P < .001]), fluoroscopy time (day, 702 vs 308 seconds, [P < .001]; night, 669 vs 313 [P < .001]), and contrast volume (day, 29 vs 13 mL [P < .001]; night, 40 vs 16 [P < .001]). Residents working day shifts reached plateau 1 day earlier in the above measures vs those on night duty. The night shift group walked more steps (P < .001), reviewed more patients (P < .001), performed worse on all cognitive assessments (P < .05), slept less (P < .05), had poorer quality of sleep (P = .001), and was more fatigued (P < .001) than the day shift group. Acquired skill was retained a week after completion of shifts. Technical skills training after night shift work enables acquisition of endovascular technical skills, although it takes longer than after day shift training. This study provides evidence for program directors to organize simulation-based training schedules for residents on night shift rotations. Copyright © 2011. Published by Mosby, Inc.

The impact of shift patterns on junior doctors' perceptions of fatigue, training, work/life balance and the role of social support

PubMed Central

Brown, M; Rapport, F; Hutchings, H; Dahlgren, A; Davies, G; Ebden, P

2010-01-01

Background The organisation of junior doctors' work hours has been radically altered following the partial implementation of the European Working Time Directive. Poorly designed shift schedules cause excessive disruption to shift workers' circadian rhythms. Method Interviews and focus groups were used to explore perceptions among junior doctors and hospital managers regarding the impact of the European Working Time Directive on patient care and doctors' well-being. Results Four main themes were identified. Under “Doctors shift rotas”, doctors deliberated the merits and demerits of working seven nights in row. They also discussed the impact on fatigue of long sequences of day shifts. “Education and training” focused on concerns about reduced on-the-job learning opportunities under the new working time arrangements and also about the difficulties of finding time and energy to study. “Work/life balance” reflected the conflict between the positive aspects of working on-call or at night and the impact on life outside work. “Social support structures” focused on the role of morale and team spirit. Good support structures in the work place counteracted and compensated for the effects of negative role stressors, and arduous and unsocial work schedules. Conclusions The impact of junior doctors' work schedules is influenced by the nature of specific shift sequences, educational considerations, issues of work/life balance and by social support systems. Poorly designed shift rotas can have negative impacts on junior doctors' professional performance and educational training, with implications for clinical practice, patient care and the welfare of junior doctors. PMID:21127102

The impact of shift patterns on junior doctors' perceptions of fatigue, training, work/life balance and the role of social support.

PubMed

Brown, M; Tucker, P; Rapport, F; Hutchings, H; Dahlgren, A; Davies, G; Ebden, P

2010-12-01

The organisation of junior doctors' work hours has been radically altered following the partial implementation of the European Working Time Directive. Poorly designed shift schedules cause excessive disruption to shift workers' circadian rhythms. Interviews and focus groups were used to explore perceptions among junior doctors and hospital managers regarding the impact of the European Working Time Directive on patient care and doctors' well-being. Four main themes were identified. Under "Doctors shift rotas", doctors deliberated the merits and demerits of working seven nights in row. They also discussed the impact on fatigue of long sequences of day shifts. "Education and training" focused on concerns about reduced on-the-job learning opportunities under the new working time arrangements and also about the difficulties of finding time and energy to study. "Work/life balance" reflected the conflict between the positive aspects of working on-call or at night and the impact on life outside work. "Social support structures" focused on the role of morale and team spirit. Good support structures in the work place counteracted and compensated for the effects of negative role stressors, and arduous and unsocial work schedules. The impact of junior doctors' work schedules is influenced by the nature of specific shift sequences, educational considerations, issues of work/life balance and by social support systems. Poorly designed shift rotas can have negative impacts on junior doctors' professional performance and educational training, with implications for clinical practice, patient care and the welfare of junior doctors.

5 CFR 550.1205 - Calculating a lump-sum payment.

Code of Federal Regulations, 2010 CFR

2010-01-01

... rate employee for all regularly scheduled periods of night shift duty covered by the unused annual... day and night shifts, the night differential is payable for that portion of the lump-sum period that would have occurred when the employee was scheduled to work night shifts. (ii) Premium pay under 5 U.S.C...

Sleep Strategies of Night-Shift Nurses on Days Off: Which Ones are Most Adaptive?

PubMed

Petrov, Megan E; Clark, C Brendan; Molzof, Hylton E; Johnson, Russell L; Cropsey, Karen L; Gamble, Karen L

2014-01-01

To determine the off-shift sleep strategies of bi-ethnic night-shift nurses, the relationship between these sleep strategies and adaptation to shift work, and identify the participant-level characteristics associated with a given sleep strategy. African-American and non-Hispanic White female, night-shift nurses from an academic hospital were recruited to complete a survey on sleep-wake patterns (n = 213). Participants completed the standard shiftwork index and the biological clocks questionnaire to determine sleep strategies and adaptation to night-shift work. In addition, chronotype was determined quantitatively with a modified version of the Munich ChronoType Questionnaire. Most participants worked ~3 consecutive 12-h night-shifts followed by several days off. Five sleep strategies used on days off were identified: (a) night stay, (b) nap proxy, (c) switch sleeper, (d) no sleep, and (e) incomplete switcher. Nap proxy and no sleep types were associated with poorer adaptation to night-shift work. The switch sleeper and incomplete switcher types were identified as more adaptive strategies that were associated with less sleep disturbance, a later chronotype, and less cardiovascular problems. Behavioral sleep strategies are related to adaptation to a typical night-shift schedule among hospital nurses. Nurses are crucial to the safety and well-being of their patients. Therefore, adoption of more adaptive sleep strategies may reduce sleep/wake dysregulation in this population, and improve cardiovascular outcomes.

Night Shift Work and Risk of Depression: Meta-analysis of Observational Studies.

PubMed

Lee, Aeyoung; Myung, Seung Kwon; Cho, Jung Jin; Jung, Yu Jin; Yoon, Jong Lull; Kim, Mee Young

2017-07-01

This study aimed to assess whether night shift work is associated with the risk of depression by using a meta-analysis of observational studies. We searched PubMed and EMBASE in August, 2016 to locate eligible studies and investigated the association between night shift work and the risk of depression, reporting outcome measures with adjusted odds ratios (ORs) or relative risks (RRs) and 95% confidence intervals (CIs). In the meta-analysis of a total of 11 observational studies with 9 cross-sectional study, 1 longitudinal study, and 1 cohort study, night shift work was significantly associated with an increased risk of depression (OR/RR, 1.43; 95% CI, 1.24-1.64; I² = 78.0%). Also, subgroup meta-analyses by gender, night shift work duration, type of occupation, continent, and type of publication showed that night shift work was consistently associated with the increased risk of depression. The current meta-analysis suggests that night shift work is associated with the increased risk of depression. However, further large prospective cohort studies are needed to confirm this association. © 2017 The Korean Academy of Medical Sciences.

Night Shift Work and Risk of Depression: Meta-analysis of Observational Studies

PubMed Central

2017-01-01

This study aimed to assess whether night shift work is associated with the risk of depression by using a meta-analysis of observational studies. We searched PubMed and EMBASE in August, 2016 to locate eligible studies and investigated the association between night shift work and the risk of depression, reporting outcome measures with adjusted odds ratios (ORs) or relative risks (RRs) and 95% confidence intervals (CIs). In the meta-analysis of a total of 11 observational studies with 9 cross-sectional study, 1 longitudinal study, and 1 cohort study, night shift work was significantly associated with an increased risk of depression (OR/RR, 1.43; 95% CI, 1.24–1.64; I2 = 78.0%). Also, subgroup meta-analyses by gender, night shift work duration, type of occupation, continent, and type of publication showed that night shift work was consistently associated with the increased risk of depression. The current meta-analysis suggests that night shift work is associated with the increased risk of depression. However, further large prospective cohort studies are needed to confirm this association. PMID:28581264

[Cardiovascular and hormonal strain in waste collection workers employed in Amsa SpA, municipality of Milan, in permanent day and night work].

PubMed

Biggi, N; Consonni, D; Fragasso, G; Lattuada, G; Perseghin, G L; Verga, R; Costa, G

2007-01-01

Aim of the study is to explore in shiftworkers: a) blood pressure and hormonal variations; b) dyslipidemia and blood glucose levels; c) insulin resistence syndrome. We have assessed 48 male workers employes in Amsa SpA, a large municipal enterprise in charge of street cleaning and domestic waste collection, in permanent day and night work as hand sweepers, motor sweepers and delivery tricar drivers. 24 of those workers (daily and nightly) were normotensive and 24 were hypertensive. Our medical checks were: physical examination: BMI; laboratory findings (blood): glucose, total cholesterol, triglycerides, endothelin, insulin, FFA, HOMA S, HOMA B, HOMA R; assay of salivary cortisol and urinary cortisol in 24 h; 24 h pressure monitoring. Nightly hypertensive: increased consumption in wine and coffee, weight and BMI, total cholesterol and FFA and endothelin. Nightly normotensive: increased consumption in cigarettes and salivary cortisol. Daily hypertensive: increased total cholesterol; 24 h pressure monitoring showed more pronounced variations of pressure in night workers both normotensive and hypertensive in working time. Night shiftwork looks like more stressfull than day shiftwork. Insuline resistance isn't noticed in all four groups.

Differences in cortisol profiles and circadian adjustment time between nurses working night shifts and regular day shifts: A prospective longitudinal study.

PubMed

Niu, Shu-Fen; Chung, Min-Huey; Chu, Hsin; Tsai, Jui-Chen; Lin, Chun-Chieh; Liao, Yuan-Mei; Ou, Keng-Liang; O'Brien, Anthony Paul; Chou, Kuei-Ru

2015-07-01

This study explored the differences in the circadian salivary cortisol profiles between nurses working night shifts and regular day shifts following a slow rotating shift schedule to assess the number of days required for adjusting the circadian rhythm of salivary cortisol levels in nurses working consecutive night shifts and the number of days off required to restore the diurnal circadian rhythm of salivary cortisol levels. This was a prospective, longitudinal, parallel-group comparative study. The participants were randomly assigned to night and day-shift groups, and saliva samples were collected to measure their cortisol levels and circadian secretion patterns. Significant differences were observed in the overall salivary cortisol pattern parameters (cortisol awakening response, changes in cortisol profiles between 6 and 12h after awakening, and changes in cortisol profiles between 30 min and 12 h after awakening) from Days 2 to 4 of the workdays between both groups. However, on Day 2 of the days off, both groups exhibited similar cortisol profiles and the cortisol profiles in the night-shift group were restored. Nurses working night shifts require at least 4 days to adjust their circadian rhythms of cortisol secretions. Moreover, on changing from night shift to other shifts, nurses must be allowed more than 2 days off work. Copyright © 2015 Elsevier Ltd. All rights reserved.

Occupational Noise Exposure of Employees at Locally-Owned Restaurants in a College Town

PubMed Central

Green, Deirdre R.; Anthony, T. Renée

2016-01-01

While many restaurant employees work in loud environments, in both dining and food preparation areas, little is known about worker exposures to noise. The risk of hearing loss to millions of food service workers around the country is unknown. This study evaluated full-shift noise exposure to workers at six locally-owned restaurants to examine risk factors associated with noise exposures during the day shift. Participants included cooks, counter attendants, bartenders, and waiters at full-service restaurants with bar service and at limited-service restaurants that provided counter service only. Assessments were made on weekdays and weekends, both during the summer and the fall (with a local university in session) to examine whether the time of week or year affects noise exposures to this population in a college town. In addition, the relationships between noise exposures and the type of restaurant and job classification were assessed. One-hundred eighty full-shift time-weighted average (TWA) exposures were assessed, using both Occupational Safety and Health Administration (OSHA) and National Institute for Occupational Safety and Health (NIOSH) criteria. No TWA measurements exceeded the 90 dBA OSHA 8 hr permissible exposure limit, although six projected TWAs exceeded the 85 dBA OSHA hearing conservation action limit. Using NIOSH criteria, TWAs ranged from 69–90 dBA with a mean of 80 dBA (SD = 4 dBA). Nearly 8% (14) of the exposures exceeded the NIOSH 8-hr 85 dBA. Full-shift exposures were larger for all workers in full-service restaurants (p < 0.001) and for cooks (p = 0.003), regardless of restaurant type. The fall semester (p = 0.003) and weekend (p = 0.048) exposures were louder than summer and weekdays. Multiple linear regression analysis suggested that the combination of restaurant type, job classification, and season had a significant effect on restaurant worker noise exposures (p < 0.001) in this college town. While evening/night shift exposures, where noise exposures may be anticipated to be louder, were not assessed, this study identified that restaurant type, job classification, time of week, and season significantly affected the noise exposures for day-shift workers. Intervention studies to prevent noise-induced hearing loss (NIHL) should consider these variables. PMID:25738733

Occupational Noise Exposure of Employees at Locally-Owned Restaurants in a College Town.

PubMed

Green, Deirdre R; Anthony, T Renée

2015-01-01

While many restaurant employees work in loud environments, in both dining and food preparation areas, little is known about worker exposures to noise. The risk of hearing loss to millions of food service workers around the country is unknown. This study evaluated full-shift noise exposure to workers at six locally-owned restaurants to examine risk factors associated with noise exposures during the day shift. Participants included cooks, counter attendants, bartenders, and waiters at full-service restaurants with bar service and at limited-service restaurants that provided counter service only. Assessments were made on weekdays and weekends, both during the summer and the fall (with a local university in session) to examine whether the time of week or year affects noise exposures to this population in a college town. In addition, the relationships between noise exposures and the type of restaurant and job classification were assessed. One-hundred eighty full-shift time-weighted average (TWA) exposures were assessed, using both Occupational Safety and Health Administration (OSHA) and National Institute for Occupational Safety and Health (NIOSH) criteria. No TWA measurements exceeded the 90 dBA OSHA 8 hr permissible exposure limit, although six projected TWAs exceeded the 85 dBA OSHA hearing conservation action limit. Using NIOSH criteria, TWAs ranged from 69-90 dBA with a mean of 80 dBA (SD = 4 dBA). Nearly 8% (14) of the exposures exceeded the NIOSH 8-hr 85 dBA. Full-shift exposures were larger for all workers in full-service restaurants (p < 0.001) and for cooks (p = 0.003), regardless of restaurant type. The fall semester (p = 0.003) and weekend (p = 0.048) exposures were louder than summer and weekdays. Multiple linear regression analysis suggested that the combination of restaurant type, job classification, and season had a significant effect on restaurant worker noise exposures (p < 0.001) in this college town. While evening/night shift exposures, where noise exposures may be anticipated to be louder, were not assessed, this study identified that restaurant type, job classification, time of week, and season significantly affected the noise exposures for day-shift workers. Intervention studies to prevent noise-induced hearing loss (NIHL) should consider these variables.

Association of rotating night shift with lipid profile among nurses in an Egyptian tertiary university hospital.

PubMed

Gadallah, Mohsen; Hakim, Sally A; Mohsen, Amira; Eldin, Waleed S

2017-06-14

The main objective was to identify whether night shift nurses are more prone to dyslipidaemia than day shift nurses. One hundred and fifty female nurses aged 20-49 years were recruited from Ain Shams University Hospitals, Egypt, from January to March 2016: 64 day shift and 86 night shift. Diet type was assessed by interview questionnaire and job satisfaction was assessed using the job satisfaction survey. Triglyceride (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) were measured in all nurses. The predictors of high TG level were ages 30-39 and ≥ 40 years and night shift. The only predictor of high LDL level (> 130 mg/dl) was age ≥ 40 years. An unhealthy diet and night shift were predictors of risky HDL levels. Seventy nurses were unsatisfied with their jobs, and 137 ate a semi-healthy diet. The findings emphasize that night shift nurses are at risk of abnormal lipid profile, therefore an occupational programme to help nurses cope with their employment conditions is necessary.

When are night shifts effective for nursing student clinical learning? Findings from a mixed-method study design.

PubMed

Palese, Alvisa; Basso, Felix; Del Negro, Elena; Achil, Illarj; Ferraresi, Annamaria; Morandini, Marzia; Moreale, Renzo; Mansutti, Irene

2017-05-01

Some nursing programmes offer night shifts for students while others do not, mainly due to the lack of evidence regarding their effectiveness on clinical learning. The principal aims of the study were to describe nursing students' perceptions and to explore conditions influencing effectiveness on learning processes during night shifts. An explanatory mixed-method study design composed of a cross-sectional study (primary method, first phase) followed by a descriptive phenomenological study design (secondary method, second phase) in 2015. Two bachelor of nursing degree programmes located in Northern Italy, three years in length and requiring night shifts for students starting in the second semester of the 1st year, were involved. First phase: all nursing students ending their last clinical placement of the academic year attended were eligible; 352 out the 370 participated. Second phase: a purposeful sample of nine students among those included in the first phase and who attended the highest amount of night shifts were interviewed. First phase: a questionnaire composed of closed and open-ended questions was adopted; data was analyzed through descriptive statistical methods. Second phase: an open-ended face-to-face audio-recorded interview was adopted and data was analyzed through content analysis. Findings from the quantitative phase, showed that students who attended night shifts reported satisfaction (44.7%) less frequently than those who attended only day shifts (55.9%). They also reported boredom (23.5%) significantly more often compared to day shift students (p=0001). Understanding of the nursing role and learning competence was significantly inferior among night shift students as compared to day shift students, while the perception of wasting time was significantly higher among night shift students compared to their counterparts. Night shift students performed nursing rounds (288; 98.2%), non-nursing tasks (247; 84.3%) and/or less often managed clinical problems (insomnia 37; 12.6% and disorientation/confusion 32; 10.9%). Findings from the qualitative phase showed night shifts are experienced by students as a "time potentially capable of generating clinical learning": learning is maximized when students play an active role, encounter patients' clinical problems and develop relationships with patients, caregivers and staff. Night shifts remains ambiguous from the students' perspective and their introduction in nursing education should be approached with care, considering the learning aims expected by students in their clinical placements and the education of clinical mentors education who should be capable of effectively involving students in the process of night care by avoiding non-nursing tasks. Copyright © 2017 Elsevier Ltd. All rights reserved.

Interaction between physical and psychosocial work risk factors for low back symptoms and its consequences amongst Indonesian coal mining workers.

PubMed

Widanarko, Baiduri; Legg, Stephen; Devereux, Jason; Stevenson, Mark

2015-01-01

This study assessed the interaction between physical and psychosocial factors for low back symptoms (LBS) and its consequences (reduced activities and absenteeism) in a developing country. A sample of 1294 Indonesian coal mining workers reported occupational exposures, LBS and its consequences using a self-administered questionnaire. Respondents were placed into one of four combination exposure groups: high physical and high psychosocial (HPhyHPsy); high physical and low psychosocial (HPhyLPsy); low physical and high psychosocial (LPhyHPsy), and; low physical and low psychosocial (LPhyLPsy). The attributable proportion due to interaction between physical and psychosocial factors was examined. Individuals in the HPhyHPsy group were most likely to report LBS (OR 5.42, 95% CI 3.30-8.89), reduced activities (OR 4.89, 95% CI 3.09-7.74), and absenteeism (OR 4.96, 95% CI 3.05-8.06). Interactions between physical and psychosocial factors were present for LBS, reduced activities, and absenteeism; although for LBS and absenteeism the interactions were not significant. Current smokers were more likely to report LBS consequences. Permanent employment and night shift work increased the odds of LBS and its consequences. We conclude that interventions aimed at reducing LBS and its consequences should address both physical and psychosocial factors, with a focus on smokers, permanent employment and night shift work. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Regulation of L1 expression and retrotransposition by melatonin and its receptor: implications for cancer risk associated with light exposure at night.

PubMed

deHaro, Dawn; Kines, Kristine J; Sokolowski, Mark; Dauchy, Robert T; Streva, Vincent A; Hill, Steven M; Hanifin, John P; Brainard, George C; Blask, David E; Belancio, Victoria P

2014-07-01

Expression of long interspersed element-1 (L1) is upregulated in many human malignancies. L1 can introduce genomic instability via insertional mutagenesis and DNA double-strand breaks, both of which may promote cancer. Light exposure at night, a recently recognized carcinogen, is associated with an increased risk of cancer in shift workers. We report that melatonin receptor 1 inhibits mobilization of L1 in cultured cells through downregulation of L1 mRNA and ORF1 protein. The addition of melatonin receptor antagonists abolishes the MT1 effect on retrotransposition in a dose-dependent manner. Furthermore, melatonin-rich, but not melatonin-poor, human blood collected at different times during the circadian cycle suppresses endogenous L1 mRNA during in situ perfusion of tissue-isolated xenografts of human cancer. Supplementation of human blood with exogenous melatonin or melatonin receptor antagonist during the in situ perfusion establishes a receptor-mediated action of melatonin on L1 expression. Combined tissue culture and in vivo data support that environmental light exposure of the host regulates expression of L1 elements in tumors. Our data imply that light-induced suppression of melatonin production in shift workers may increase L1-induced genomic instability in their genomes and suggest a possible connection between L1 activity and increased incidence of cancer associated with circadian disruption. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Sleep Strategies of Night-Shift Nurses on Days Off: Which Ones are Most Adaptive?

PubMed Central

Petrov, Megan E.; Clark, C. Brendan; Molzof, Hylton E.; Johnson, Russell L.; Cropsey, Karen L.; Gamble, Karen L.

2014-01-01

Objectives: To determine the off-shift sleep strategies of bi-ethnic night-shift nurses, the relationship between these sleep strategies and adaptation to shift work, and identify the participant-level characteristics associated with a given sleep strategy. Methods: African-American and non-Hispanic White female, night-shift nurses from an academic hospital were recruited to complete a survey on sleep–wake patterns (n = 213). Participants completed the standard shiftwork index and the biological clocks questionnaire to determine sleep strategies and adaptation to night-shift work. In addition, chronotype was determined quantitatively with a modified version of the Munich ChronoType Questionnaire. Most participants worked ~3 consecutive 12-h night-shifts followed by several days off. Results: Five sleep strategies used on days off were identified: (a) night stay, (b) nap proxy, (c) switch sleeper, (d) no sleep, and (e) incomplete switcher. Nap proxy and no sleep types were associated with poorer adaptation to night-shift work. The switch sleeper and incomplete switcher types were identified as more adaptive strategies that were associated with less sleep disturbance, a later chronotype, and less cardiovascular problems. Conclusion: Behavioral sleep strategies are related to adaptation to a typical night-shift schedule among hospital nurses. Nurses are crucial to the safety and well-being of their patients. Therefore, adoption of more adaptive sleep strategies may reduce sleep/wake dysregulation in this population, and improve cardiovascular outcomes. PMID:25566182

Acute Sleep Deprivation and Circadian Misalignment Associated with Transition onto the First Night of Work Impairs Visual Selective Attention

PubMed Central

Santhi, Nayantara; Horowitz, Todd S.; Duffy, Jeanne F.; Czeisler, Charles A.

2007-01-01

Background Overnight operations pose a challenge because our circadian biology promotes sleepiness and dissipates wakefulness at night. Since the circadian effect on cognitive functions magnifies with increasing sleep pressure, cognitive deficits associated with night work are likely to be most acute with extended wakefulness, such as during the transition from a day shift to night shift. Methodology/Principal Findings To test this hypothesis we measured selective attention (with visual search), vigilance (with Psychomotor Vigilance Task [PVT]) and alertness (with a visual analog scale) in a shift work simulation protocol, which included four day shifts followed by three night shifts. There was a nocturnal decline in cognitive processes, some of which were most pronounced on the first night shift. The nighttime decrease in visual search sensitivity was most pronounced on the first night compared with subsequent nights (p = .04), and this was accompanied by a trend towards selective attention becoming ‘fast and sloppy’. The nighttime increase in attentional lapses on the PVT was significantly greater on the first night compared to subsequent nights (p<.05) indicating an impaired ability to sustain focus. The nighttime decrease in subjective alertness was also greatest on the first night compared with subsequent nights (p<.05). Conclusions/Significance These nocturnal deficits in attention and alertness offer some insight into why occupational errors, accidents, and injuries are pronounced during night work compared to day work. Examination of the nighttime vulnerabilities underlying the deployment of attention can be informative for the design of optimal work schedules and the implementation of effective countermeasures for performance deficits during night work. PMID:18043740

Bright-light exposure during daytime sleeping affects nocturnal melatonin secretion after simulated night work.

PubMed

Nagashima, Shunsuke; Osawa, Madoka; Matsuyama, Hiroto; Ohoka, Wataru; Ahn, Aemi; Wakamura, Tomoko

2018-02-01

The guidelines for night and shift workers recommend that after night work, they should sleep in a dark environment during the daytime. However, staying in a dark environment during the daytime reduces nocturnal melatonin secretion and delays its onset. Daytime bright-light exposure after night work is important for melatonin synthesis the subsequent night and for maintaining the circadian rhythms. However, it is not clear whether daytime sleeping after night work should be in a dim- or a bright-light environment for maintaining melatonin secretion. The aim of this study, therefore, was to evaluate the effect of bright-light exposure during daytime sleeping on nocturnal melatonin secretion after simulated night work. Twelve healthy male subjects, aged 24.8 ± 4.6 (mean ± SD), participated in 3-day sessions under two experimental conditions, bright light or dim light, in a random order. On the first day, the subjects entered the experimental room at 16:00 and saliva samples were collected every hour between 18:00 and 00:00 under dim-light conditions. Between 00:00 and 08:00, they participated in tasks that simulated night work. At 10:00 the next morning, they slept for 6 hours under either a bright-light condition (>3000 lx) or a dim-light condition (<50 lx). In the evening, saliva samples were collected as on the first day. The saliva samples were analyzed for melatonin concentration. Activity and sleep times were recorded by a wrist device worn throughout the experiment. In the statistical analysis, the time courses of melatonin concentration were compared between the two conditions by three-way repeated measurements ANOVA (light condition, day and time of day). The change in dim light melatonin onset (ΔDLMO) between the first and second days, and daytime and nocturnal sleep parameters after the simulated night work were compared between the light conditions using paired t-tests. The ANOVA results indicated a significant interaction (light condition and3 day) (p = .006). Post hoc tests indicated that in the dim-light condition, the melatonin concentration was significantly lower on the second day than on the first day (p = .046); however, in the bright-light condition, there was no significant difference in the melatonin concentration between the days (p = .560). There was a significant difference in ΔDLMO between the conditions (p = .015): DLMO after sleeping was advanced by 11.1 ± 17.4 min under bright-light conditions but delayed for 7.2 ± 13.6 min after sleeping under dim-light conditions. No significant differences were found in any sleep parameter. Our study demonstrated that daytime sleeping under bright-light conditions after night work could not reduce late evening melatonin secretion until midnight or delay the phase of melatonin secretion without decreasing the quality of the daytime sleeping. Thus, these results suggested that, to enhance melatonin secretion and to maintain their conventional sleep-wake cycle, after night work, shift workers should sleep during the daytime under bright-light conditions rather than dim-light conditions.

Effect of the first night shift period on sleep in young nurse students.

PubMed

Fietze, Ingo; Knoop, Karsten; Glos, Martin; Holzhausen, Martin; Peter, Jan Giso; Penzel, Thomas

2009-12-01

In young hospital nurses being exposed to a night shift work schedule for the first time in their occupational life, sleep quality is investigated quantitatively. A main sleep period and supplementary sleep periods were defined and analyzed to investigate sleep behavior and quality. A total of 30 young nurses (26 women, 4 men), mean age 20.2 +/- 2.1 years participated. A 3 week nursing school period was followed by a 3 week work period with a 3-5 night shift sub-period and recovery days. Sleep-wake behavior was assessed with an actigraph, sleep diaries, Epworth sleepiness scale (ESS), and quality of life was assessed with a standard questionnaire (SF-36). Comparing the school period with the work shift period when excluding recovery days after night shift period significant increase of total sleep time within 24 h was found during the work days (ANOVA P < 0.05). During the night shift sub-period, there was just a small decline of the main sleep period at day (n.s.) which was not compensated by supplementary sleep episodes. The supplementary sleep during work day varied between 11 min (school period) and 18 min after recovery days from night shift (n.s.). Young healthy nurses tolerate the first night shift exposure very well, according to objective and subjective parameters related to quality of sleep. An increased sleep need during work days lead to longer total sleep time, but do not lead to longer supplementary sleep episodes. Young nurses tolerate the first rotating shift period and the first night shift period very well.

Association between shift work and the risk of death from biliary tract cancer in Japanese men.

PubMed

Lin, Yingsong; Nishiyama, Takeshi; Kurosawa, Michiko; Tamakoshi, Akiko; Kubo, Tatsuhiko; Fujino, Yoshihisa; Kikuchi, Shogo

2015-10-21

There is increasing evidence suggesting that shift work involving night work may increase cancer risk. We examined the association between working rotating shifts and the risk of death from biliary tract cancer among Japanese men who participated in the Japan Collaborative Cohort Study. Of the 46,395 men recruited, 22,224 men aged 40-65 at baseline (1988-1990) who reported working full-time or were self-employed were included in the present analysis. The study subjects were followed through December 31, 2009. Information regarding occupation and lifestyle factors was collected using a self-administered questionnaire. Cox proportional hazard models were used to estimate the hazard ratio (HR) and 95 % confidence interval (CI) for the risk of death from biliary tract cancer in relation to shift work. During a mean 17-year follow-up, we observed 94 biliary tract cancer deaths, including 23 deaths from gallbladder cancer and 71 deaths from extrahepatic bile duct cancer. Overall, shift work was associated with a statistically non-significant increase in the risk of biliary tract cancer, with an HR of 1.50 (95 % CI: 0.81-2.77), among rotating shift workers. When the analysis was limited to extrahepatic bile duct cancer, a significant association appeared, with a multivariable-adjusted HR of 1.93 (95 % CI: 1.00-3.72) for rotating shift workers. Our data indicate that shift work may be associated with increased risk of death from extrahepatic bile duct cancer in this cohort of Japanese men. The association with gallbladder cancer remains unclear because of the small number of deaths.

Night-shift work and breast cancer risk in a cohort of Chinese women.

PubMed

Pronk, Anjoeka; Ji, Bu-Tian; Shu, Xiao-Ou; Xue, Shouzheng; Yang, Gong; Li, Hong-Lan; Rothman, Nathaniel; Gao, Yu-Tang; Zheng, Wei; Chow, Wong-Ho

2010-05-01

Shift work involving disruption of circadian rhythms has been classified as a probable cause of human cancer by the International Agency for Research on Cancer, based on limited epidemiologic evidence and abundant experimental evidence. The authors investigated this association in a population-based prospective cohort study of Chinese women. At baseline (1996-2000), information on lifetime occupational history was obtained from 73,049 women. Lifetime night-shift exposure indices were created using a job exposure matrix. During 2002-2004, self-reported data on frequency and duration of night-shift work were collected. Hazard ratios and 95% confidence intervals, adjusted for major breast cancer risk factors, were calculated. During follow-up through 2007, 717 incident cases of breast cancer were diagnosed. Breast cancer risk was not associated with ever working the night shift on the basis of the job exposure matrix (adjusted hazard ratio = 1.0, 95% confidence interval: 0.9, 1.2) or self-reported history of night-shift work (adjusted hazard ratio = 0.9, 95% confidence interval: 0.7, 1.1). Risk was also not associated with frequency, duration, or cumulative amount of night-shift work. There were no indications of effect modification. The lack of an association between night-shift work and breast cancer adds to the inconsistent epidemiologic evidence. It may be premature to consider shift work a cause of cancer.

Patient Handoffs: Is Cross Cover or Night Shift Better?

PubMed

Higgins, Alanna; Brannen, Melissa L; Heiman, Heather L; Adler, Mark D

2017-06-01

Studies show singular handoffs between health care providers to be risky. Few describe sequential handoffs or compare handoffs from different provider types. We investigated the transfer of information across 2 handoffs using a piloted survey instrument. We compared cross-cover (every fourth night call) with dedicated night-shift residents. Surveys assessing provider knowledge of hospitalized patients were administered to pediatric residents. Primary teams were surveyed about their handoff upon completion of daytime coverage of a patient. Night-shift or cross-covering residents were surveyed about their handoff of the same patient upon completion of overnight coverage. Pediatric hospitalists rated the consistency of information between the surveys. Absolute difference was calculated between the 2 providers' rating of a patient's (a) complexity and (b) illness severity. Scores were compared across provider type. Fifty-nine complete handoff pairs were obtained. Fourteen and 45 handoff surveys were completed by a cross-covering and a night-shift provider, respectively. There was no significant difference in information consistency between primary and night-shift (median, 4.0; interquartile range [IQR], 3-4) versus primary and cross-covering providers (median, 4.0; IQR, 3-4). There was no significant difference in median patient complexity ratings (night shift, 3.0; IQR, 1-5, versus cross cover, 3.5; IQR, 1-5) or illness severity ratings (night shift, 2.0; IQR, 1-4, versus cross-cover, 3.0; IQR, 1-6) when comparing provider types giving a handoff. We did not find a difference in physicians' transfer of information during 2 handoffs among providers taking traditional call or on night shift. Development of tools to measure handoff consistency is needed.

Differential sleep, sleepiness, and neurophysiology in the insomnia phenotypes of shift work disorder.

PubMed

Gumenyuk, Valentina; Belcher, Ren; Drake, Christopher L; Roth, Thomas

2015-01-01

To characterize and compare insomnia symptoms within two common phenotypes of Shift Work Disorder. Observational laboratory and field study. Hospital sleep center. 34 permanent night workers. Subjects were classified by Epworth Sleepiness Scale and Insomnia Severity Index into 3 subgroups: asymptomatic controls, alert insomniacs (AI), and sleepy insomniacs (SI). Sleep parameters were assessed by sleep diary. Circadian phase was evaluated by dim-light salivary melatonin onset (DLMO). Objective sleepiness was measured using the multiple sleep latency test (MSLT). Brain activity was measured using the N1 event-related potential (ERP). A tandem repeat in PER3 was genotyped from saliva DNA. (1) AI group showed normal MSLT scores but elevated N1 amplitudes indicating cortical hyperarousal. (2) SI group showed pathologically low MSLT scores but normal N1 amplitudes. (3) AI and SI groups were not significantly different from one another in circadian phase, while controls were significantly phase-delayed relative to both SWD groups. (4) AI showed significantly longer sleep latencies and lower sleep efficiency than controls during both nocturnal and diurnal sleep. SI significantly differed from controls in nocturnal sleep parameters, but differences during diurnal sleep periods were smaller and not statistically significant. (5) Genotype × phenotype χ² analysis showed significant differences in the PER3 VNTR: 9 of 10 shift workers reporting sleepiness in a post hoc genetic substudy were found to carry the long tandem repeat on PER3, while 4 of 14 shift workers without excessive sleepiness carried the long allele. Our results suggest that the sleepy insomnia phenotype is comprehensively explained by circadian misalignment, while the alert insomnia phenotype resembles an insomnia disorder precipitated by shift work. © 2014 Associated Professional Sleep Societies, LLC.

A combined field and laboratory design for assessing the impact of night shift work on police officer operational performance.

PubMed

Waggoner, Lauren B; Grant, Devon A; Van Dongen, Hans P A; Belenky, Gregory; Vila, Bryan

2012-11-01

This study assessed the utility of a combined field and laboratory research design for measuring the impact of consecutive night shift work on the sleepiness, vigilance, and driving performance of police patrol officers. For police patrol officers working their normal night shift duty cycles, simulated driving performance and psychomotor vigilance were measured in a laboratory on two separate occasions: in the morning after the last of five consecutive 10.7-h night shifts, and at the same time in the morning after three consecutive days off duty. Order of participation in conditions was randomized among subjects. Subjects experienced manipulation of sleep schedules due to working night shifts in a real operational environment, but performance testing was conducted under controlled laboratory conditions. N = 29 active-duty police patrol officers (27 male, 2 female; age 37.1 ± 6.3 years) working night shift schedules participated in this study. Simulated driving performance, psychomotor vigilance, and subjective sleepiness were significantly degraded following 5 consecutive night shifts as compared to 3 consecutive days off duty, indicating that active-duty police officers are susceptible to performance degradation as a consequence of working nights. This combined field and laboratory research design succeeded in bridging the gap between the realism of the operational environment and the control of laboratory performance testing, demonstrating that this is a useful approach for addressing the relationship between shift work induced fatigue and critical operational task performance.

Rotating night shift work, sleep, and colorectal adenoma in women.

PubMed

Devore, Elizabeth E; Massa, Jennifer; Papantoniou, Kyriaki; Schernhammer, Eva S; Wu, Kana; Zhang, Xuehong; Willett, Walter C; Fuchs, Charles S; Chan, Andrew T; Ogino, Shuji; Giovannucci, Edward; Wei, Esther K

2017-07-01

This study aims to investigate the associations of rotating night shift work history and sleep duration with risk of colorectal adenoma. We evaluated 56,275 cancer-free participants of the Nurses' Health Study II, who had their first colonoscopy or sigmoidoscopy between 1991 and 2011; rotating night shift work and sleep duration were reported by mailed questionnaire. Multivariable-adjusted logistic regression was used to estimate relative risks (RR) of colorectal adenoma, with 95% confidence intervals (CI), across categories of rotating night shift work history (none, 1-4, 5-9, and ≥10 years) and sleep duration (≤5, 6, 7, 8, and ≥9 h/day). We found no association between duration of rotating night shift work and occurrence of colorectal adenoma (p-trend across shift work categories = 0.5). Women with the longest durations of rotating night shift work (≥10 years) had a similar risk of adenoma compared to women without a history of rotating night shift work (multivariable-adjusted RR = 0.96, 95% CI = 0.83-1.11). Similarly, there were no associations of shorter or longer sleep durations with adenoma risk (p-trend = 0.2 across sleep durations of ≤5 through 7 h/day and p-trend = 0.5 across sleep durations of 7 through ≥9 h/day). Results were similar when we examined associations according to adenoma location and subtype. Our results do not support an association between rotating night shift work or sleep duration and risk of colorectal adenoma in women.

Who benefits from family support? Work schedule and family differences.

PubMed

Jennings, Kristen S; Sinclair, Robert R; Mohr, Cynthia D

2016-01-01

Prior research has demonstrated the benefits of family-supportive organization perceptions (FSOP) for reducing stress, increasing satisfaction, and increasing worker commitment; however, less research has studied health outcomes or possible differences in the effects of FSOP based on worker characteristics. The present study examined relationships between FSOP and health outcomes, as well as how those relationships may depend on work schedule and family differences. Using a sample of 330 acute care nurses, the findings indicated that FSOP predicted several health and well-being outcomes obtained 9 months later. Further, the relationships between FSOP and the outcome variables depended on some work schedule and family differences. In terms of family differences, FSOP was most strongly related to life satisfaction for those who cared for dependent adults. The relationship between FSOP and health outcomes of depression, musculoskeletal pain, and physical health symptoms were generally significant for workers with dependent children, but not significant for workers with no children. Regarding schedule differences, the relationship between FSOP and life satisfaction was significant for those on nonstandard (evening/night) shifts but not significant for standard day shift workers; however, there were no differences in FSOP relationships by number of hours worked per week. The findings demonstrate that FSOP may benefit some employees more than others. Such differences need to be incorporated into both future work-family theory development and into efforts to document the effectiveness of family-supportive policies, programs, and practices. (c) 2016 APA, all rights reserved).

A prospective study of psychomotor performance of driving among two kinds of shift work in Iran

PubMed Central

Saadat, Soheil; Karbakhsh, Mojgan; Saremi, Mahnaz; Alimohammadi, Iraj; Ashayeri, Hassan; Fayaz, Mahsa; Rostami, Reza

2018-01-01

Background and aim Driving after a night shift imposes a risk on health care professionals and other road users. The aim of this study was to measure psychomotor performance of driving of night shift nurses compared to day-shift nurses. Methods Forty-seven volunteer female nurses working at Sina hospital in Tehran, Iran, with a call in all departments of hospital, participated in this study (23 night shift and 24 day shift nurses) in 2016. The tests included RT for simple reaction time, ATAVT for perceptual speed, LVT for visual orientation and ZBA for time anticipation. Data collection tools were individual characteristics, 11-item circadian type inventory (CTI), Stanford sleepiness scale (SSS), and Swedish occupational fatigue inventory (SOFI-20) questionnaires. Psychomotor driving performance was assessed using validated computerized traffic psychological battery of Vienna Test System (VTS), before and after the shifts. Data analysis was performed using paired-samples t-test and Linear Regression. Results The mean age of day and night-shift nurses were 31.4±5.6 and 28.7±3.9 years respectively, no significant difference between two groups. Thirty percent of night shift and 16.7% of day shift nurses reported traffic accidents in the past year. The results revealed that, scores based on viewing times in visual orientation test (p=0.005), and median reaction time score in choice reaction time and reactive stress tolerance test (p=0.045), had a significant association with a 12-hour night shift with a 3-hour nap. Conclusions Twelve-hour night shift work impairs choice reaction time and visual orientation in nurses, even though they take a 3- hour nap during the shift. These skills are required for safe driving. PMID:29629067

Night shift work and other determinants of estradiol, testosterone, and dehydroepiandrosterone sulfate among middle-aged nurses and midwives.

PubMed

Peplonska, Beata; Bukowska, Agnieszka; Lie, Jenny Anne; Gromadzinska, Jolanta; Zienolddiny, Shanbeh

2016-09-01

The aims of our study were to (i) investigate the association between rotating night shift work and blood concentrations of estradiol, testosterone and dehydroepiandrosterone sulfate (DHEAS) and (2) evaluate the role of their non-occupational determinants. A cross-sectional study was conducted on 345 premenopausal and 187 postmenopausal nurses and midwives (263 women working rotating night shifts and 269 women working during days). Data from in-person interviews were used, anthropometric measurements were performed, and body mass index (BMI) and waist- to-hip ratio were calculated. Morning blood and spot urine samples were collected. Multiple linear regression models were fitted with hormone concentrations as dependent variables, and night shift work characteristics and demographic, reproductive, lifestyle and anthropometric determinants as independent variables. Modification of the effect by chronotype was examined. Among postmenopausal women, we observed a statistically significant positive association between the total duration of night shift work >15 years and estradiol level (P<0.05 when compared to night work duration <5 years). Night shift work characteristics were significantly associated with estradiol among morning-type postmenopausal women. The well-established associations between hormones and their major determinants, such as age and BMI, were confirmed. The findings of our study imply that prolonged night shift work may be associated with increased estradiol levels among postmenopausal women, especially among the morning-type postmenopausal women.

Night Shift Work Increases the Risks of Multiple Primary Cancers in Women: A Systematic Review and Meta-analysis of 61 Articles.

PubMed

Yuan, Xia; Zhu, Chenjing; Wang, Manni; Mo, Fei; Du, Wei; Ma, Xuelei

2018-01-01

A growing number of studies have examined associations between night shift work and the risks of common cancers among women, with varying conclusions. We did a meta-analysis to identify whether long-term night shift work increased the risks of common cancers in women. We enrolled 61 articles involving 114,628 cases and 3,909,152 participants from Europe, North America, Asia, and Australia. Risk estimates were performed with a random-effect model or a fixed-effect model. Subgroup analyses and meta-regression analyses about breast cancer were conducted to explore possible sources of heterogeneity. In addition, we carried out a dose-response analysis to quantitatively estimate the accumulative effect of night shift work on the risk of breast cancer. A positive relationship was revealed between long-term night shift work and the risks of breast [OR = 1.316; 95% confidence interval (CI), 1.196-1.448], digestive system (OR = 1.177; 95% CI, 1.065-1.301), and skin cancer (OR = 1.408; 95% CI, 1.024-1.934). For every 5 years of night shift work, the risk of breast cancer in women was increased by 3.3% (OR = 1.033; 95% CI, 1.012-1.056). Concerning the group of nurses, long-term night shift work presented potential carcinogenic effect in breast cancer (OR = 1.577; 95% CI, 1.235-2.014), digestive system cancer (OR = 1.350; 95% CI, 1.030-1.770), and lung cancer (OR = 1.280; 95% CI, 1.070-1.531). This systematic review confirmed the positive association between night shift work and the risks of several common cancers in women. We identified that cancer risk of women increased with accumulating years of night shift work, which might help establish and implement effective measures to protect female night shifters. Cancer Epidemiol Biomarkers Prev; 27(1); 25-40. ©2018 AACR . ©2018 American Association for Cancer Research.

The effects of consecutive night shifts and shift length on cognitive performance and sleepiness: a field study.

PubMed

Haidarimoghadam, Rashid; Kazemi, Reza; Motamedzadeh, Majid; Golmohamadi, Rostam; Soltanian, Alireza; Zoghipaydar, Mohamad Reza

2017-06-01

The aim of this study was to evaluate the effects of consecutive night shifts (CNS) and shift length on cognitive performance and sleepiness. This study evaluated the sleepiness and performance of 30 control room operators (CROs) working in 7 nights, 7 days, 7 days off (7N7D7O) and 30 CROs working in 4 nights, 7 days, 3 nights, 7 days off (4N7D3N7O) shift patterns in a petrochemical complex on the last night shift before swinging into the day shift. To assess cognitive performance, the n-back test, continuous performance test and simple reaction time test were employed. To assess sleepiness, the Karolinska sleepiness scale was used. Both schedules indicated that the correct responses and response times of working memory were reduced (p = 0.001), while intentional errors and sleepiness increased during the shift work (p = 0.001). CNS had a significant impact on reaction time and commission errors (p = 0.001). The main duty of CROs at a petrochemical plant is checking hazardous processes which require appropriate alertness and cognitive performance. As a result, planning for appropriate working hours and suitable number of CNS in a rotating shift system is a contribution to improving CRO performance and enhancing safety.

Night shift work and incidence of diabetes in the Danish Nurse Cohort.

PubMed

Hansen, Anne B; Stayner, Leslie; Hansen, Johnni; Andersen, Zorana J

2016-04-01

Night shift work has been associated with poor sleep, weight gain, metabolic syndrome, which are recognised risk factor for diabetes. However, only a few studies have examined the effect of shift work on diabetes risk. Here, we study the association between shift work and incidence of diabetes in Danish nurses. We used the Danish Nurse Cohort with 28,731 participating female nurses recruited in 1993 (19,898) or 1999 (8833), when self-reported baseline information on diabetes prevalence, lifestyle and working time were collected, and followed them in the Danish Diabetes Register for incidence of diabetes until 2013. Nurses reported whether they worked night, evening, rotating or day shifts. We analysed the association between working time and diabetes incidence using a Cox proportional hazards model adjusted for diabetes risk factors, separately with and without adjustment for body mass index (BMI) which might be an intermediate variable. Of 19,873 nurses who worked and were diabetes-free at recruitment, 837 (4.4%) developed diabetes during 15 years of follow-up. The majority of nurses (62.4%) worked day shifts, 21.8% rotating shift, 10.1% evening and 5.5% night shifts. Compared with nurses who worked day shifts, we found statistically significantly increased risk of diabetes in nurses who worked night (1.58; 1.25 to 1.99) or evening shifts (1.29; 1.04 to 1.59) in the fully adjusted models including BMI. Danish nurses working night and evening shifts have increased risk for diabetes, with the highest risk associated with current night shift work. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Under-reporting of work-related musculoskeletal disorders in the Veterans Administration.

PubMed

Siddharthan, Kris; Hodgson, Michael; Rosenberg, Deborah; Haiduven, Donna; Nelson, Audrey

2006-01-01

Work-related musculoskeletal disorders following patient contact represent a major concern for health care workers. Unfortunately, research and prevention have been hampered by difficulties ascertaining true prevalence rates owing to under-reporting of these injuries. The purpose of this study is to determine the predictors for under-reporting work-related musculoskeletal injuries and their reasons. Multivariate analysis using data obtained in a survey of Veterans Administration employees in the USA was used to determine underreporting patterns among registered nurses, licensed practical nurses and nursing assistants. Focus groups among health care workers were conducted at one of the largest Veterans Administration hospitals to determine reasons for under-reporting. A significant number of workers reported work-related musculoskeletal pain, which was not reported as an injury but required rescheduling work such as changing shifts and taking sick leave to recuperate. The findings indicate that older health care workers and those with longer service were less likely to report as were those working in the evening and night shifts. Hispanic workers and personnel who had repetitive injuries were prone to under-reporting, as were workers in places that lack proper equipment to move and handle patients. Reasons for under-reporting include the time involved, peer pressure not to report and frustration with workers' compensation procedures. This study provides insights into under-reporting musculoskeletal injuries in a major US government organization. The research indicates that current reporting procedures appear to be overtly cumbersome in time and effort. More flexible work assignments are needed to cover staff shortfalls owing to injuries. Health education on the detrimental long-term effects of ergonomic injuries and the need for prompt attention to injuries should prove useful in improving rates of reporting.

Violence against health workers in Family Medicine Centers.

PubMed

Al-Turki, Nouf; Afify, Ayman Am; AlAteeq, Mohammed

2016-01-01

Health care violence is a significant worldwide problem with negative consequences on both the safety and well-being of health care workers as well as workplace activities. Reports examining health care violence in Saudi Arabia are limited and the results are conflicting. To estimate the prevalence and determine the demographic and occupational characteristics associated with workplace violence in primary care centers in Riyadh, Saudi Arabia. A cross-sectional study included 270 health care workers in 12 family medicine centers in Riyadh during November and December 2014. A structured self-administered questionnaire was used to estimate the frequency, timing, causes, reactions, and consequences of workplace violence plus participants' demographic and occupational data. A total 123 health care workers (45.6%) experienced some kind of violence over 12 months prior to the study. These included physical (6.5%) and nonphysical violence (99.2%), including verbal violence (94.3%) and intimidation (22.0%). Offenders were patients (71.5%) in the majority of cases, companions (20.3%), or both (3.3%). Almost half (48.0%) of health care workers who experienced violence did nothing, 38.2% actively reported the event, and 13.8% consulted a colleague. A significant association of workplace violence was found with working multiple shifts, evening or night shift, and lack of an encouraging environment to report violence. Workplace violence is still a significant problem in primary care centers. The high frequency of violence together with underreporting may indicate the inefficiency of the current safety program. More safety programs and training activities for health care workers, efficient reporting system, and zero tolerance policies need to be implemented to minimize workplace violence against health workers.

Violence against health workers in Family Medicine Centers

PubMed Central

Al-Turki, Nouf; Afify, Ayman AM; AlAteeq, Mohammed

2016-01-01

Background Health care violence is a significant worldwide problem with negative consequences on both the safety and well-being of health care workers as well as workplace activities. Reports examining health care violence in Saudi Arabia are limited and the results are conflicting. Objective To estimate the prevalence and determine the demographic and occupational characteristics associated with workplace violence in primary care centers in Riyadh, Saudi Arabia. Methods A cross-sectional study included 270 health care workers in 12 family medicine centers in Riyadh during November and December 2014. A structured self-administered questionnaire was used to estimate the frequency, timing, causes, reactions, and consequences of workplace violence plus participants’ demographic and occupational data. Results A total 123 health care workers (45.6%) experienced some kind of violence over 12 months prior to the study. These included physical (6.5%) and nonphysical violence (99.2%), including verbal violence (94.3%) and intimidation (22.0%). Offenders were patients (71.5%) in the majority of cases, companions (20.3%), or both (3.3%). Almost half (48.0%) of health care workers who experienced violence did nothing, 38.2% actively reported the event, and 13.8% consulted a colleague. A significant association of workplace violence was found with working multiple shifts, evening or night shift, and lack of an encouraging environment to report violence. Conclusion Workplace violence is still a significant problem in primary care centers. The high frequency of violence together with underreporting may indicate the inefficiency of the current safety program. More safety programs and training activities for health care workers, efficient reporting system, and zero tolerance policies need to be implemented to minimize workplace violence against health workers. PMID:27330300

Scheduling and shift work characteristics associated with risk for occupational injury in newly licensed registered nurses: An observational study.

PubMed

Stimpfel, Amy Witkoski; Brewer, Carol S; Kovner, Christine T

2015-11-01

Registered nurses across the globe bear a heavy injury burden. Every shift, nurses are exposed to a variety of hazards that can jeopardize their health, which negatively impacts their ability to provide high-quality patient care. Previous research suggests that inexperienced, or newly licensed nurses, may have an increased risk for certain occupational injuries. However, the current knowledge base is insufficient to fully understand how work hours influence newly licensed nurses' occupational injury, given the significant variation in hospital organization and work characteristics. To describe newly licensed nurses' shift work characteristics and determine the association between shift type and scheduling characteristics and nurse injury, before and after adjusting for individual and combined effects of demographics, external context, organizational context, and work context, following the Organization of Work model. This study is a secondary analysis of a nationally representative survey of newly licensed registered nurses using a cross-sectional design. The analytic sample includes 1744 newly licensed registered nurses from 34 states and the District of Columbia who reported working in a hospital and were within 6-18 months of passing their state licensure exam at the time of survey administration. Descriptive statistics were calculated, followed by bivariate and multivariate Poisson regression models to assess the relationship between shift type and scheduling characteristics and nurse injury. Lastly, full models with the addition of demographics, external context, organizational context, and work context variables were calculated. The majority (79%) of newly licensed nurses worked 12-h shifts, a near majority worked night shift (44%), and over half (61%) worked overtime (mandatory or voluntary) weekly. Nurses working weekly overtime were associated with a 32% [incidence rate ratio (IRR) 1.32, CI 1.07-1.62] increase in the risk of a needle stick and nurses working night shift were associated with a 16% [IRR 1.16, CI 1.02-1.33] increase in the risk of a sprain or strain injury. Overtime and night shift work were significantly associated with increased injury risk in newly licensed nurses independent of other work factors and demographic characteristics. The findings warrant further study given the long-term consequences of these injuries, costs associated with treatment, and loss of worker productivity. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effect of blue-enriched white light on cognitive performances and sleepiness of night-shift workers: A field study.

PubMed

Motamedzadeh, Majid; Golmohammadi, Rostam; Kazemi, Reza; Heidarimoghadam, Rashid

2017-08-01

Night-shift works are basically accompanied by reduced cognitive performance, sleepiness, and higher possibility for human error and related incidents. It is therefore crucial to improve individuals' performance and alertness in sensitive places like industries' control room with the ultimate goal of increasing efficiency and reducing the number of possible incidents. Previous research has indicated that blue light is a critical cue for entraining circadian rhythm. As a result, the present study was an attempt to investigate whether blue-enriched white light illumination was a practical strategy to decrease sleepiness and improve cognitive performance during night shifts. The study, which adopted a before-after interventional design, was conducted among 30 control room staff members of petrochemical industry. After baseline assessments under existing lighting conditions, every participant was exposed to two new lighting conditions (namely, 17,000K and 6500K blue-enriched white light), each lasting for a week. Assessments were conducted again at the end of these treatments. In order to measure the subjective sleepiness, Karolinska Sleepiness Scale (KSS) was utilized. Subjects also performed the Conners' Continuous Performance Test II (CPT-II) and 1-back test in order to gauge their cognitive performance, and melatonin assessment was carried out using salivary and Eliza technique. The data was analyzed using two-way repeated measure ANOVA. The results indicated that, compared to normal lighting conditions, participants' sleepiness and melatonin rhythm significantly declined when they were exposed to blue-enriched white light. Furthermore, the experimental condition had a significant effect on the reduction of working memory errors. It also decreased omission errors and the reaction time during the sustained attention task. Thus, using blue-enriched white light may be a proper ergonomic strategy for improving performance and alertness, especially during night, in sensitive environments like control rooms. Copyright © 2017 Elsevier Inc. All rights reserved.

Simulated night shift work induces circadian misalignment of the human peripheral blood mononuclear cell transcriptome.

PubMed

Kervezee, Laura; Cuesta, Marc; Cermakian, Nicolas; Boivin, Diane B

2018-05-22

Misalignment of the endogenous circadian timing system leads to disruption of physiological rhythms and may contribute to the development of the deleterious health effects associated with night shift work. However, the molecular underpinnings remain to be elucidated. Here, we investigated the effect of a 4-day simulated night shift work protocol on the circadian regulation of the human transcriptome. Repeated blood samples were collected over two 24-hour measurement periods from eight healthy subjects under highly controlled laboratory conditions before and 4 days after a 10-hour delay of their habitual sleep period. RNA was extracted from peripheral blood mononuclear cells to obtain transcriptomic data. Cosinor analysis revealed a marked reduction of significantly rhythmic transcripts in the night shift condition compared with baseline at group and individual levels. Subsequent analysis using a mixed-effects model selection approach indicated that this decrease is mainly due to dampened rhythms rather than to a complete loss of rhythmicity: 73% of transcripts rhythmically expressed at baseline remained rhythmic during the night shift condition with a similar phase relative to habitual bedtimes, but with lower amplitudes. Functional analysis revealed that key biological processes are affected by the night shift protocol, most notably the natural killer cell-mediated immune response and Jun/AP1 and STAT pathways. These results show that 4 days of simulated night shifts leads to a loss in temporal coordination between the human circadian transcriptome and the external environment and impacts biological processes related to the adverse health effects associated to night shift work.

Circadian rhythm adaptation to simulated night shift work: effect of nocturnal bright-light duration.

PubMed

Eastman, C I; Liu, L; Fogg, L F

1995-07-01

We compared bright-light durations of 6, 3 and 0 hours (i.e. dim light) during simulated night shifts for phase shifting the circadian rectal temperature rhythm to align with a 12-hour shift of the sleep schedule. After 10 baseline days there were 8 consecutive night-work, day-sleep days, with 8-hour sleep (dark) periods. The bright light (about 5,000 lux, around the baseline temperature minimum) was used during all 8 night shifts, and dim light was < 500 lux. This was a field study in which subjects (n = 46) went outside after the night shifts and slept at home. Substantial circadian adaptation (i.e. a large cumulative temperature rhythm phase shift) was produced in many subjects in the bright light groups, but not in the dim light group. Six and 3 hours of bright light were each significantly better than dim light for phase shifting the temperature rhythm, but there was no significant difference between 6 and 3 hours. Thus, durations > 3 hours are probably not necessary in similar shift-work situations. Larger temperature rhythm phase shifts were associated with better subjective daytime sleep, less subjective fatigue and better overall mood.

Portrayals of Pro-Beijing Workers' Night Schools in Hong Kong from 1946 to Post-1997

ERIC Educational Resources Information Center

Lau, Chui Shan

2011-01-01

This study focuses on the transformation of pro-Beijing labour education in the socio-political context of Hong Kong. It explores the reasons that Hong Kong pro-Beijing educators initiated Workers' Night Schools for adults; the organisation of schools in many locales and the transformation of labour education that workers received in these…

Napping during night shift: practices, preferences, and perceptions of critical care and emergency department nurses.

PubMed

Fallis, Wendy M; McMillan, Diana E; Edwards, Marie P

2011-04-01

Nurses working night shifts are at risk for sleep deprivation, which threatens patient and nurse safety. Little nursing research has addressed napping, an effective strategy to improve performance, reduce fatigue, and increase vigilance. To explore nurses' perceptions, experiences, barriers, and safety issues related to napping/not napping during night shift. A convenience sample of critical care nurses working night shift were interviewed to explore demographics, work schedule and environment, and napping/ not napping experiences, perceptions, and barriers. Transcripts were constantly compared, and categories and themes were identified. Participants were 13 critical care nurses with an average of 17 years' experience. Ten nurses napped regularly; 2 avoided napping because of sleep inertia. The need for and benefits of napping or not during night shift break were linked to patient and nurse safety. Ability to nap was affected by the demands of patient care and safety, staffing needs, and organizational and environmental factors. Nurses identified personal health, safety, and patient care issues supporting the need for a restorative nap during night shift. Barriers to napping exist within the organization/work environment.

The effects of a self-selected nap opportunity on the psychophysiological, performance and subjective measures during a simulated industrial night shift regimen.

PubMed

Davy, Jonathan; Göbel, Matthias

2013-01-01

This study compared the effects of a 1 h self-selected recovery period to those of a standard night shift arrangement (with a total break time of 1-h) over a simulated three-day night shift schedule in a laboratory setting. Results showed that the inclusion of the flexible nap scheme resulted in higher performance output, improvements in physiological strain responses and reduced sleepiness during each night shift and generally over the three-night cycle. Certain variables also revealed the impact of napping compared with the standard rest break condition on the circadian rhythm. The sleep diary records show that the inclusion of the current intervention did not significantly reduce daytime recovery sleep. The results suggest that the potential benefits of flexible napping may outweigh the logistical effort it requires in a workplace environment. Consensus on appropriate napping strategies for shift work remains a challenge. This simulated night shift laboratory study sought to determine the effects of a 1-h self-selected nap opportunity relative to a normal shift set-up. The nap improved performance and decreased sleepiness, without affecting daytime sleep.

Four days of simulated shift work reduces insulin sensitivity in humans.

PubMed

Bescos, R; Boden, M J; Jackson, M L; Trewin, A J; Marin, E C; Levinger, I; Garnham, A; Hiam, D S; Falcao-Tebas, F; Conte, F; Owens, J A; Kennaway, D J; McConell, G K

2018-06-01

The aim of this study was to investigate the effects of 4 consecutive simulated night shifts on glucose homeostasis, mitochondrial function and central and peripheral rhythmicities compared with a simulated day shift schedule. Seventeen healthy adults (8M:9F) matched for sleep, physical activity and dietary/fat intake participated in this study (night shift work n = 9; day shift work n = 8). Glucose tolerance and insulin sensitivity before and after 4 nights of shift work were measured by an intravenous glucose tolerance test and a hyperinsulinaemic euglycaemic clamp respectively. Muscles biopsies were obtained to determine insulin signalling and mitochondrial function. Central and peripheral rhythmicities were assessed by measuring salivary melatonin and expression of circadian genes from hair samples respectively. Fasting plasma glucose increased (4.4 ± 0.1 vs. 4.6 ± 0.1 mmol L -1 ; P = .001) and insulin sensitivity decreased (25 ± 7%, P < .05) following the night shift, with no changes following the day shift. Night shift work had no effect on skeletal muscle protein expression (PGC1α, UCP3, TFAM and mitochondria Complex II-V) or insulin-stimulated pAkt Ser473, pTBC1D4Ser318 and pTBC1D4Thr642. Importantly, the metabolic changes after simulated night shifts occurred despite no changes in the timing of melatonin rhythmicity or hair follicle cell clock gene expression across the wake period (Per3, Per1, Nr1d1 and Nr1d2). Only 4 days of simulated night shift work in healthy adults is sufficient to reduce insulin sensitivity which would be expected to increase the risk of T2D. © 2018 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Auditory Attention and Comprehension During a Simulated Night Shift: Effects of Task Characteristics.

PubMed

Pilcher, June J; Jennings, Kristen S; Phillips, Ginger E; McCubbin, James A

2016-11-01

The current study investigated performance on a dual auditory task during a simulated night shift. Night shifts and sleep deprivation negatively affect performance on vigilance-based tasks, but less is known about the effects on complex tasks. Because language processing is necessary for successful work performance, it is important to understand how it is affected by night work and sleep deprivation. Sixty-two participants completed a simulated night shift resulting in 28 hr of total sleep deprivation. Performance on a vigilance task and a dual auditory language task was examined across four testing sessions. The results indicate that working at night negatively impacts vigilance, auditory attention, and comprehension. The effects on the auditory task varied based on the content of the auditory material. When the material was interesting and easy, the participants performed better. Night work had a greater negative effect when the auditory material was less interesting and more difficult. These findings support research that vigilance decreases during the night. The results suggest that auditory comprehension suffers when individuals are required to work at night. Maintaining attention and controlling effort especially on passages that are less interesting or more difficult could improve performance during night shifts. The results from the current study apply to many work environments where decision making is necessary in response to complex auditory information. Better predicting the effects of night work on language processing is important for developing improved means of coping with shiftwork. © 2016, Human Factors and Ergonomics Society.

Restless Legs Syndrome/Willis-Ekbom Disease Is Prevalent in Working Nurses, but Seems Not to Be Associated with Shift Work Schedules.

PubMed

Waage, Siri; Pallesen, Ståle; Moen, Bente Elisabeth; Bjorvatn, Bjørn

2018-01-01

Insomnia and excessive sleepiness are among the most commonly reported sleep problems related to shift work. Sleep-related movement disorders have, however, received far less attention in relation to such work schedules. The objective of this study was to investigate the association between different shift work schedules and the prevalence of Restless legs syndrome/Willis-Ekbom disease (RLS/WED) in a large sample of Norwegian nurses. Our hypothesis was that shift working nurses would report higher prevalence of RLS/WED compared to day workers. A total of 1,788 nurses with different work schedules (day work, two-shift rotation, night work, three shift rotation) participated in a cohort study, started in 2008/2009. Four questions about RLS/WED based on the diagnostic criteria were included in wave 4 (2012). RLS/WED prevalence rates across different shift schedules were explored by the Pearson chi-square test. Logistic regression analysis was used to assess the association between RLS/WED and work schedules and shift work disorder (SWD) with adjustment for sex, age, marital status, smoking, and caffeine use. In total, 90.0% of the nurses were females, mean age 36.5 years (SD = 8.6, range 25-67). The overall prevalence of RLS/WED was 26.8%. We found no significant differences between the prevalence of RLS/WED across the different shift schedules, ranging from 23.3% (day work) to 29.4% (night work). There was a significant difference ( p  < 0.001) in the prevalence of RLS/WED between nurses having SWD (33.5%) compared to nurses not having SWD (23.8%). SWD remained significantly associated with RLS/WED in the adjusted logistic regression analysis (1.56, CI: 1.24-1.97). This study did not support the hypothesis. RLS/WED was associated with SWD, which might indicate that nurses vulnerable to shift work also are sensitive to other complaints related to a misalignment of the biological clock.

The correlation between urinary 5-hydroxyindoleacetic acid and sperm quality in infertile men and rotating shift workers.

PubMed

Ortiz, Águeda; Espino, Javier; Bejarano, Ignacio; Lozano, Graciela M; Monllor, Fabián; García, Juan F; Pariente, José A; Rodríguez, Ana B

2010-11-08

Serotonin is a neurotransmitter that modulates a wide range of neuroendocrine functions. However, excessive circulating serotonin levels may induce harmful effects in the male reproductive system. The objective of this study was to evaluate whether the levels of urinary 5-hydroxyindoleacetic acid (5-HIIA), a major serotonin metabolite, correlate with different classical seminal parameters. Human ejaculates were obtained from 40 men attending infertility counselling and rotating shift workers by masturbation after 4-5 days of abstinence. Urinary 5- HIIA concentration was quantified by using a commercial ELISA kit. Forward motility was assessed by a computer-aided semen analysis (CASA) system. Sperm concentration was determined using the haemocytometer method. Sperm morphology was evaluated after Diff-Quik staining, while sperm vitality was estimated after Eosin-Nigrosin vital staining. Our results show that urinary 5-HIIA levels obtained from a set of 20 volunteers negatively correlated with sperm concentration, forward motility, morphology normal range and sperm vitality. On the other hand, we checked the relationship between male infertility and urinary 5-HIIA levels in 20 night shift workers. Thus, urinary 5-HIIA levels obtained from 10 recently-proven fathers were significantly lower than those found in 10 infertile males. Additionally, samples from recent fathers exhibited higher sperm concentration, as well as better forward motility and normal morphology rate. In the light of our findings, we concluded that high serotonin levels, indirectly measured as urinary 5-HIIA levels, appear to play a role as an infertility determinant in male subjects.

Stress at work and mental health status among female hospital workers.

PubMed Central

Estryn-Behar, M; Kaminski, M; Peigne, E; Bonnet, N; Vaichere, E; Gozlan, C; Azoulay, S; Giorgi, M

1990-01-01

Relations between working conditions and mental health status of female hospital workers were studied in a sample of 1505 women: 43% were nurses, 32% auxiliaries, and 7% ancillary staff; 13% were other qualified health care staff, mainly head nurses; 5% had occupations other than direct health care; 63% worked on the morning, 20% on the afternoon, and 17% on the night shift. Data were collected at the annual routine medical visit by the occupational health practitioner, using self administered questionnaires and clinical assessments. Five health indicators were considered: a high score to the general health questionnaire (GHQ); fatigue; sleep impairment; use of antidepressants, sleeping pills, or sedatives; and diagnosis of psychiatric morbidity at clinical assessment. Four indices of stress at work were defined: job stress, mental load, insufficiency in internal training and discussion, and strain caused by schedule. The analysis was conducted by multiple logistic regression, controlling for type of occupation, shift, number of years of work in hospital, daily travel time to work, age, marital status, number of children, and wish to move house. Sleep impairment was mostly linked to shift and strain due to schedule. For all other indicators of mental health impairment and especially high GHQ scores, the adjusted odds ratios increased significantly with the levels of job stress, mental load, and strain due to schedule. This evidence of association between work involving an excessive cumulation of stress factors and mental wellbeing should be considered in interventions aimed at improving the working conditions of hospital workers. PMID:2310704

Effects of modifications to the health and social sector's collective agreement on the objective characteristics of working hours.

PubMed

Ropponen, Annina; Vanttola, Päivi; Koskinen, Aki; Hakola, Tarja; Puttonen, Sampsa; Härmä, Mikko

2017-08-08

This study aimed to evaluate the effects of an intervention on objective working-hour characteristics. The intervention involved making modifications to the collective agreement that would limit employees' entitlement to time off as compensation. The intervention group consisted of 493 and the control group of 2,303 health and social care shift workers, respectively. We analysed the objective pay roll-based working-hour data for 2012-2013, which we obtained from employers' records, using the repeated measures mixed model. The changes in objective working-hour characteristics were small, but systematic. The intervention had some positive effects: the amount of short recovery periods (<28 h) after the last night shift decreased from 5% to 3%, and the amount of working weeks of over 48 h decreased from 19% to 17%. The realization of employees' shift preferences increased from 18% to 20%. However, in contrast, consecutive work shifts and the number of scheduled absences increased and days off decreased, suggesting less time for recovery and thus a negative trend in shift ergonomics. When planning shifts, nursing management should avoid regulations that promote specific unhealthy shift characteristics, that is, consecutive work shifts and less days off.

Effects of modifications to the health and social sector’s collective agreement on the objective characteristics of working hours

PubMed Central

ROPPONEN, Annina; VANTTOLA, Päivi; KOSKINEN, Aki; HAKOLA, Tarja; PUTTONEN, Sampsa; HÄRMÄ, Mikko

2017-01-01

This study aimed to evaluate the effects of an intervention on objective working-hour characteristics. The intervention involved making modifications to the collective agreement that would limit employees’ entitlement to time off as compensation. The intervention group consisted of 493 and the control group of 2,303 health and social care shift workers, respectively. We analysed the objective pay roll-based working-hour data for 2012–2013, which we obtained from employers’ records, using the repeated measures mixed model. The changes in objective working-hour characteristics were small, but systematic. The intervention had some positive effects: the amount of short recovery periods (<28 h) after the last night shift decreased from 5% to 3%, and the amount of working weeks of over 48 h decreased from 19% to 17%. The realization of employees’ shift preferences increased from 18% to 20%. However, in contrast, consecutive work shifts and the number of scheduled absences increased and days off decreased, suggesting less time for recovery and thus a negative trend in shift ergonomics. When planning shifts, nursing management should avoid regulations that promote specific unhealthy shift characteristics, that is, consecutive work shifts and less days off. PMID:28420807

Medical Supplies Shortages and Burnout among Greek Health Care Workers during Economic Crisis: a Pilot Study

PubMed Central

Rachiotis, George; Kourousis, Christos; Kamilaraki, Maria; Symvoulakis, Emmanouil K.; Dounias, George; Hadjichristodoulou, Christos

2014-01-01

Greece has been seriously affected by the economic crisis. In 2011 there were reports of 40% reduction to public hospital budgets. Occasional shortages of medical supplies have been reported in mass media. We attempted to pivotally investigate the frequency of medical supplies shortages in two Greek hospital units of the National Health System and to also assess their possible impact on burnout risk of health care workers. We conducted a cross-sectional study (n=303) of health care workers in two Greek hospitals who were present at the workplace during a casually selected working day (morning shift work). The Maslach Burnout Inventory (MBI) was used as the measure of burnout. An additional questionnaire was used about demographics, and working conditions (duration of employment, cumulative night shifts, type of hospital including medical supplies shortages and their impact on quality of healthcare. The prevalence of emotional exhaustion, depersonalization and low personal accomplishment was 44.5%, 43.2% and 51.5%, respectively. Medical supply shortages were significantly associated with emotional exhaustion and depersonalization. This finding provides preliminary evidence that austerity has affected health care in Greece. Moreover, the medical supply shortages in Greek hospitals may reflect the unfolding humanitarian crisis of the country. PMID:24688306

Sleep inertia during a simulated 6-h on/6-h off fixed split duty schedule.

PubMed

Hilditch, Cassie J; Short, Michelle; Van Dongen, Hans P A; Centofanti, Stephanie A; Dorrian, Jillian; Kohler, Mark; Banks, Siobhan

Sleep inertia is a safety concern for shift workers returning to work soon after waking up. Split duty schedules offer an alternative to longer shift periods, but introduce additional wake-ups and may therefore increase risk of sleep inertia. This study investigated sleep inertia across a split duty schedule. Sixteen participants (age range 21-36 years; 10 females) participated in a 9-day laboratory study with two baseline nights (10 h time in bed, [TIB]), four 24-h periods of a 6-h on/6-h off split duty schedule (5-h TIB in off period; 10-h TIB per 24 h) and two recovery nights. Two complementary rosters were evaluated, with the timing of sleep and wake alternating between the two rosters (2 am/2 pm wake-up roster versus 8 am/8 pm wake-up roster). At 2, 17, 32 and 47 min after scheduled awakening, participants completed an 8-min inertia test bout, which included a 3-min psychomotor vigilance test (PVT-B), a 3-min Digit-Symbol Substitution Task (DSST), the Karolinska Sleepiness Scale (KSS), and the Samn-Perelli Fatigue Scale (SP-Fatigue). Further testing occurred every 2 h during scheduled wakefulness. Performance was consistently degraded and subjective sleepiness/fatigue was consistently increased during the inertia testing period as compared to other testing times. Morning wake-ups (2 am and 8 am) were associated with higher levels of sleep inertia than later wake-ups (2 pm and 8 pm). These results suggest that split duty workers should recognise the potential for sleep inertia after waking, especially during the morning hours.

Work stress, premenstrual syndrome and dysphoric disorder: are there any associations?

PubMed

Namavar Jahromi, B; Pakmehr, S; Hagh-Shenas, H

2011-03-01

Women with recurrent and severe symptoms are diagnosed as having premenstrual syndrome (PMS), and if they suffer from severe affective symptoms, a diagnosis of premenstrual dysphoric disorder (PMDD) is made. The purpose of this study was to determine the association of work stress with PMS and PMDD. Fifty-five female medical students in their internship program (ten 24-hour shifts per month) and 38 third-year female medical students without any shift duties were asked to participate in this study. A questionnaire was used to record demographic information and a self-report inventory was used to measure 13 symptoms relevant to PMS and PMDD according to DSM-IV criteria. All participants were asked to complete the inventory every night around midnight for those on shifts or before going to bed at home for 60 consecutive nights. Out of 55 volunteers in the shift-work group, 31 (56%) fulfilled the diagnostic criteria for PMS in contrast to 12 (32%) in the control group. The frequency of PMDD was 12 (22%) in the intern group and 5 (13%) in the control group. Twenty one students (55%) from the control group did not have PMS or PMDD, compared to 12 (22%) students from the shift workers. Decreased energy (70.9%) and irritability (65.4%) were the most frequent symptoms during the luteal phase in the shift-work group. Work stress and an increase in responsibility may produce or exacerbate PMS. Self-help approaches to induce self-awareness, along with psychological and psychiatric interventions, may help susceptible women to overcome this cyclic condition in order to increase their productivity as well as their quality of life.

Laparoscopic skills suffer on the first shift of sequential night shifts: program directors beware and residents prepare.

PubMed

Leff, Daniel R; Aggarwal, Rajesh; Rana, Mariam; Nakhjavani, Batool; Purkayastha, Sanjay; Khullar, Vik; Darzi, Ara W

2008-03-01

Research evaluating fatigue-induced skills decline has focused on acute sleep deprivation rather than the effects of circadian desynchronization associated with multiple shifts. As a result, the number of consecutive night shifts that residents can safely be on duty without detrimental effects to their technical skills remains unknown. A prospective observational cohort study was conducted to assess the impact of 7 successive night shifts on the technical surgical performance of junior residents. The interventional strategy included training 21 residents from surgery and allied disciplines on a virtual reality surgical simulator, towards the achievement of preset benchmark scores, followed by 294 technical skills assessments conducted over 1764 manpower night shift hours. Primary outcomes comprised serial technical skills assessments on 2 tasks of a virtual reality surgical simulator. Secondary outcomes included assessments of introspective fatigue, duration of sleep, and prospective recordings of activity (number of "calls" received, steps walked, and patients evaluated). Maximal deterioration in performance was observed following the first night shift. Residents took significantly longer to complete the first (P = 0.002) and second tasks (P = 0.005) compared with baseline. They also committed significantly greater numbers of errors (P = 0.025) on the first task assessed. Improved performance was observed across subsequent shifts towards baseline levels. Newly acquired technical surgical skills deteriorate maximally after the first night shift, emphasizing the importance of adequate preparation for night rotas. Performance improvements across successive shifts may be due to ongoing learning or adaptation to chronic fatigue. Further research should focus on assessments of both technical procedural skills and cognitive abilities to determine the rotas that best minimize errors and maximize patient safety.

Differential Sleep, Sleepiness, and Neurophysiology in the Insomnia Phenotypes of Shift Work Disorder

PubMed Central

Gumenyuk, Valentina; Belcher, Ren; Drake, Christopher L.; Roth, Thomas

2015-01-01

Study Objectives: To characterize and compare insomnia symptoms within two common phenotypes of Shift Work Disorder. Design: Observational laboratory and field study. Setting: Hospital sleep center. Participants: 34 permanent night workers. Subjects were classified by Epworth Sleepiness Scale and Insomnia Severity Index into 3 subgroups: asymptomatic controls, alert insomniacs (AI), and sleepy insomniacs (SI). Measurements: Sleep parameters were assessed by sleep diary. Circadian phase was evaluated by dim-light salivary melatonin onset (DLMO). Objective sleepiness was measured using the multiple sleep latency test (MSLT). Brain activity was measured using the N1 event-related potential (ERP). A tandem repeat in PER3 was genotyped from saliva DNA. Results: (1) AI group showed normal MSLT scores but elevated N1 amplitudes indicating cortical hyperarousal. (2) SI group showed pathologically low MSLT scores but normal N1 amplitudes. (3) AI and SI groups were not significantly different from one another in circadian phase, while controls were significantly phase-delayed relative to both SWD groups. (4) AI showed significantly longer sleep latencies and lower sleep efficiency than controls during both nocturnal and diurnal sleep. SI significantly differed from controls in nocturnal sleep parameters, but differences during diurnal sleep periods were smaller and not statistically significant. (5) Genotype × phenotype χ2 analysis showed significant differences in the PER3 VNTR: 9 of 10 shift workers reporting sleepiness in a post hoc genetic substudy were found to carry the long tandem repeat on PER3, while 4 of 14 shift workers without excessive sleepiness carried the long allele. Conclusions: Our results suggest that the sleepy insomnia phenotype is comprehensively explained by circadian misalignment, while the alert insomnia phenotype resembles an insomnia disorder precipitated by shift work. Citation: Gumenyuk V, Belcher R, Drake CL, Roth T. Differential sleep, sleepiness, and neurophysiology in the insomnia phenotypes of shift work disorder. SLEEP 2015;38(1):119–126. PMID:25325466

The impact of shift duration on the efficacy and tolerability of armodafinil in patients with excessive sleepiness associated with shift work disorder.

PubMed

Harsh, John; Yang, Ronghua; Hull, Steven G

2014-05-01

To examine the impact of night-shift duration (≤9 hours or >9 hours) on efficacy and tolerability of armodafinil in patients with shift work disorder (SWD). This was a post hoc analysis of a 6 week, multicenter, randomized, double-blind, placebo-controlled, parallel-group study. Shift workers with diagnosed SWD and late-in-shift sleepiness (between 4 am and 8 am, including the commute home) received armodafinil 150 mg or placebo before their night shift. Proportion of patients with at least minimal improvement in late-in-shift sleepiness, late-in-shift Clinical Global Impressions-Change (CGI-C) rating and Karolinska Sleepiness Scale (KSS), as well as overall Global Assessment of Functioning (GAF) scale and modified Sheehan Disability Scale (SDS-M), were assessed at baseline and final visit. Of the 383 patients enrolled, 279 (73%) worked shifts ≤9 hours and 104 (27%) worked shifts >9 hours. A greater percentage of patients receiving armodafinil had at least minimal improvement in late-in-shift CGI-C (≤9 hours: 78% vs 60%, P = 0.0017; >9 hours: 77% vs 46%, P = 0.0020) regardless of shift duration. Armodafinil patients also demonstrated significantly greater improvements in GAF score (≤9 hours: 9.5 vs 5.4, P < 0.0001; >9 hours: 9.6 vs 4.3, P = 0.0019) and KSS score (≤9 hours: -2.9 vs -1.9, P = 0.0002; >9 hours: -2.8 vs -1.6, P = 0.00 28). Improvement in SDS-M composite score was significantly greater for armodafinil patients working >9 hours (-6.8 vs -2.7, P = 0.0086). Headache was the most frequent adverse event in all treatment groups. Patients receiving armodafinil had significantly greater improvements in late-in-shift clinical condition and in wakefulness and overall global functioning than did placebo-treated patients, regardless of shift duration. Prospectively designed, randomized clinical trials that include objective measures of sleepiness are needed to support these findings.

Shift Work and Sleep Quality Among Urban Police Officers

PubMed Central

Fekedulegn, Desta; Burchfiel, Cecil M.; Charles, Luenda E.; Hartley, Tara A.; Andrew, Michael E.; Violanti, John M.

2016-01-01

Objective The aim of the study was to examine association of shift work with sleep quality in police officers. Methods Data were obtained from the Buffalo Cardio-Metabolic Occupational Police Stress study (n =363). An electronic work history database was used to define shift as day, afternoon, or night for three durations: past month, 1 year, and 15 years. Sleep quality was determined using the Pittsburgh Sleep Quality Index. Results The overall prevalence of poor sleep quality was 54%; 44% for day, 60% for afternoon, and 69% for night shift. Poor sleep quality was 70% more prevalent among night-shift officers (P <0.001) and 49% higher among those on the afternoon shift (P =0.003) relative to officers working on the day shift. Conclusions Night and evening work schedules are associated with elevated prevalence of poor sleep quality among police officers. PMID:26949891

Shift Work and Sleep Quality Among Urban Police Officers: The BCOPS Study.

PubMed

Fekedulegn, Desta; Burchfiel, Cecil M; Charles, Luenda E; Hartley, Tara A; Andrew, Michael E; Violanti, John M

2016-03-01

The aim of the study was to examine association of shift work with sleep quality in police officers. Data were obtained from the Buffalo Cardio-Metabolic Occupational Police Stress study (n = 363). An electronic work history database was used to define shift as day, afternoon, or night for three durations: past month, 1 year, and 15 years. Sleep quality was determined using the Pittsburgh Sleep Quality Index. The overall prevalence of poor sleep quality was 54%; 44% for day, 60% for afternoon, and 69% for night shift. Poor sleep quality was 70% more prevalent among night-shift officers (P < 0.001) and 49% higher among those on the afternoon shift (P = 0.003) relative to officers working on the day shift. Night and evening work schedules are associated with elevated prevalence of poor sleep quality among police officers.

Why things go bump in the night

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shapiro, D.E.

1996-09-01

Visual processing leads to false security. Professor Emeritus Herschel W. Leibowitz of Pennsylvania State University pointed out some important facts about night-time navigation-vehicular or other - in a 1995 Distinguished Scientific Award Address, printed last spring in American Psychologist. People are often more tired at night. If they are working overtime or doing shift work, their systems are probably off-kilter. Unquestionably, they cannot see as well at night-night myopia has been investigated since the 18th century. The problem is this: with those factors so obvious, why do people fail to compensate for them by changing their driving habits enough tomore » balance out the risks? First, researchers poking around in, among other places, the brains of hamsters, discovered that there are two functionally separate visual processing systems. The orientation and guidance system is much less sensitive to the amount of light than is the focal systems; the latter is the system with which we recognize objects. That means a worker can securely find his or her way to the substation entrance form the parking lot, despite low light, but can easily stumble in an unexpected pot-hole on the way. Or a driver can stick to his lane, with the familiar help of feedback from the steering wheel, but be too slow to identify objects in the road.« less

A meta-analysis including dose-response relationship between night shift work and the risk of colorectal cancer.

PubMed

Wang, Xiao; Ji, Alin; Zhu, Yi; Liang, Zhen; Wu, Jian; Li, Shiqi; Meng, Shuai; Zheng, Xiangyi; Xie, Liping

2015-09-22

A meta-analysis was conducted to quantitatively evaluate the correlation between night shift work and the risk of colorectal cancer. We searched for publications up to March 2015 using PubMed, Web of Science, Cochrane Library, EMBASE and the Chinese National Knowledge Infrastructure databases, and the references of the retrieved articles and relevant reviews were also checked. OR and 95% CI were used to assess the degree of the correlation between night shift work and risk of colorectal cancer via fixed- or random-effect models. A dose-response meta-analysis was performed as well. The pooled OR estimates of the included studies illustrated that night shift work was correlated with an increased risk of colorectal cancer (OR = 1.318, 95% CI 1.121-1.551). No evidence of publication bias was detected. In the dose-response analysis, the rate of colorectal cancer increased by 11% for every 5 years increased in night shift work (OR = 1.11, 95% CI 1.03-1.20). In conclusion, this meta-analysis indicated that night shift work was associated with an increased risk of colorectal cancer. Further researches should be conducted to confirm our findings and clarify the potential biological mechanisms.

Paradoxical post-exercise responses of acylated ghrelin and leptin during a simulated night shift.

PubMed

Morris, Christopher J; Fullick, Sarah; Gregson, Warren; Clarke, Neil; Doran, Dominic; MacLaren, Don; Atkinson, Greg

2010-05-01

Approximately 10% of employees undertake night work, which is a significant predictor of weight gain, possibly because responses to activity and eating are altered at night. It is known that the appetite-related hormone, acylated ghrelin, is suppressed after an acute bout of exercise during the day, but no researcher has explored whether evening exercise alters acylated ghrelin and other appetite-related outcomes during a subsequent night shift. Six healthy men (mean +/- SD: age 30 +/- 8 yrs, body mass index 23.1 +/- 1.1 kg/m(2)) completed two crossover trials (control and exercise) in random order. Participants fasted from 10:00 h, consumed a test meal at 18:00 h, and then cycled at 50% peak oxygen uptake or rested between 19:00-20:00 h. Participants then completed light activities during a simulated night shift which ended at 05:00 h. Two small isocaloric meals were consumed at 22:00 and 02:00 h. Venous blood samples were drawn via cannulation at 1 h intervals between 19:00-05:00 h for the determination of acylated ghrelin, leptin, insulin, glucose, triglyceride, and non-esterified fatty acids concentrations. Perceived hunger and wrist actimetry were also recorded. During the simulated night shift, mean +/- SD acylated ghrelin concentration was 86.5 +/- 40.8 pg/ml following exercise compared with 71.7 +/- 37.7 pg/ml without prior exercise (p = 0.015). Throughout the night shift, leptin concentration was 263 +/- 242 pg/ml following exercise compared with 187 +/- 221 pg/ml without prior exercise (p = 0.017). Mean levels of insulin, triglyceride, non-esterified fatty acids, and wrist actimetry level were also higher during the night shift that followed exercise (p < 0.05). These data indicate that prior exercise increases acylated ghrelin and leptin concentrations during a subsequent simulated night shift. These findings differ from the known effects of exercise on acylated ghrelin and leptin during the day, and therefore have implications for energy balance during night work.

Violence toward health workers in Bahrain Defense Force Royal Medical Services' emergency department.

PubMed

Rafeea, Faisal; Al Ansari, Ahmed; Abbas, Ehab M; Elmusharaf, Khalifa; Abu Zeid, Mohamed S

2017-01-01

Employees working in emergency departments (EDs) in hospital settings are disproportionately affected by workplace violence as compared to those working in other departments. Such violence results in minor or major injury to these workers. In other cases, it leads to physical disability, reduced job performance, and eventually a nonconducive working environment for these workers. A cross-sectional exploratory questionnaire was used to collect data used for the examination of the incidents of violence in the workplace. This study was carried out at the ED of the Bahrain Defense Force (BDF) Hospital. Participants for the study were drawn from nurses, support staff, and emergency physicians. Both male and female workers were surveyed. The study included responses from 100 staff in the ED of the BDF Hospital in Bahrain (doctors, nurses, and support personnel). The most experienced type of violence in the workers in the past 12 months in this study was verbal abuse, which was experienced by 78% of the participants, which was followed by physical abuse (11%) and then sexual abuse (3%). Many cases of violence against ED workers occurred during night shifts (53%), while physical abuse was reported to occur during all the shifts; 40% of the staff in the ED of the hospital were not aware of the policies against workplace violence, and 26% of the staff considered leaving their jobs at the hospital. This study reported multiple findings on the number of workplace violence incidents, as well as the characteristics and factors associated with violence exposure in ED staff in Bahrain. The results clearly demonstrate the importance of addressing the issue of workplace violence in EDs in Bahrain and can be used to demonstrate the strong need for interventions.

Varied exposure to carcinogenic, mutagenic, and reprotoxic (CMR) chemicals in occupational settings in France.

PubMed

Havet, Nathalie; Penot, Alexis; Morelle, Magali; Perrier, Lionel; Charbotel, Barbara; Fervers, Béatrice

2017-02-01

To explore varied exposure to carcinogenic, mutagenic, and reprotoxic chemicals (CMR) for French employees. Our study assessed data from the French national cross-sectional survey of occupational risks (SUMER) that was conducted in 2010 in a national representative sample of employees. We selected 28 CMR agents that were classified by the International Agency for Research on Cancer or European Union as being known or presumed to have CMR potential in humans. The association of individual and job characteristics with exposure prevalence, duration, and intensity of the CMR agents during a 1-week period was examined using multilevel logistic regression analysis. Overall, 10.4% of employees in 2010 were exposed to one or more CMR agents at their workplace, and 3.4% were subjected to multiple CMR exposures. Blue-collar workers, night-shift workers and workers with short-term employment contracts experienced higher exposure prevalence (p < 0.01) and intensity (p < 0.05). Blue-collar workers and shift workers experienced also longer exposure duration (p < 0.001). Conversely, managers, workers of large companies, and women were less exposed to CMR agents (p < 0.001). The presence of a Committee for Health, Safety, and Working Conditions, and intervention by Occupational Health and Safety officers were significantly associated with reduced exposure intensities (p < 0.001 and p < 0.05). Establishment of European CMR regulations and the existence of an applicable substitution principle reduced the exposure duration (p < 0.001) and intensity (p < 0.05). Our results point out disparities in CMR exposure and identify high-priority targets for prevention measures to help reducing social health discrepancies.

Violence toward health workers in Bahrain Defense Force Royal Medical Services’ emergency department

PubMed Central

Rafeea, Faisal; Al Ansari, Ahmed; Abbas, Ehab M; Elmusharaf, Khalifa; Abu Zeid, Mohamed S

2017-01-01

Background Employees working in emergency departments (EDs) in hospital settings are disproportionately affected by workplace violence as compared to those working in other departments. Such violence results in minor or major injury to these workers. In other cases, it leads to physical disability, reduced job performance, and eventually a nonconducive working environment for these workers. Materials and methods A cross-sectional exploratory questionnaire was used to collect data used for the examination of the incidents of violence in the workplace. This study was carried out at the ED of the Bahrain Defense Force (BDF) Hospital. Participants for the study were drawn from nurses, support staff, and emergency physicians. Both male and female workers were surveyed. Results The study included responses from 100 staff in the ED of the BDF Hospital in Bahrain (doctors, nurses, and support personnel). The most experienced type of violence in the workers in the past 12 months in this study was verbal abuse, which was experienced by 78% of the participants, which was followed by physical abuse (11%) and then sexual abuse (3%). Many cases of violence against ED workers occurred during night shifts (53%), while physical abuse was reported to occur during all the shifts; 40% of the staff in the ED of the hospital were not aware of the policies against workplace violence, and 26% of the staff considered leaving their jobs at the hospital. Conclusion This study reported multiple findings on the number of workplace violence incidents, as well as the characteristics and factors associated with violence exposure in ED staff in Bahrain. The results clearly demonstrate the importance of addressing the issue of workplace violence in EDs in Bahrain and can be used to demonstrate the strong need for interventions. PMID:29184452

Napping on the Night Shift: A Study of Sleep, Performance, and Learning in Physicians-in-Training.

PubMed

McDonald, Jennifer; Potyk, Darryl; Fischer, David; Parmenter, Brett; Lillis, Teresa; Tompkins, Lindsey; Bowen, Angela; Grant, Devon; Lamp, Amanda; Belenky, Gregory

2013-12-01

Physicians in training experience fatigue from sleep loss, high workload, and working at an adverse phase of the circadian rhythm, which collectively degrades task performance and the ability to learn and remember. To minimize fatigue and sustain performance, learning, and memory, humans generally need 7 to 8 hours of sleep in every 24-hour period. In a naturalistic, within-subjects design, we studied 17 first- and second-year internal medicine residents working in a tertiary care medical center, rotating between day shift and night float every 4 weeks. We studied each resident for 2 weeks while he/she worked the day shift and for 2 weeks while he/she worked the night float, objectively measuring sleep by wrist actigraphy, vigilance by the Psychomotor Vigilance Task test, and visual-spatial and verbal learning and memory by the Brief Visuospatial Memory Test-Revised and the Rey Auditory-Verbal Learning Test. Residents, whether working day shift or night float, slept approximately 7 hours in every 24-hour period. Residents, when working day shift, consolidated their sleep into 1 main sleep period at night. Residents working night float split their sleep, supplementing their truncated daytime sleep with nighttime on-duty naps. There was no difference in vigilance or learning and memory, whether residents worked day shift or night float. Off-duty sleep supplemented with naps while on duty appears to be an effective strategy for sustaining vigilance, learning, and memory when working night float.

Aromatherapy alleviates endothelial dysfunction of medical staff after night-shift work: preliminary observations.

PubMed

Shimada, Kenei; Fukuda, Shota; Maeda, Kumiko; Kawasaki, Toshihiro; Kono, Yasushi; Jissho, Satoshi; Taguchi, Haruyuki; Yoshiyama, Minoru; Yoshikawa, Junichi

2011-02-01

Night-shift work causes mental stress and lifestyle changes, and is recognized as a risk of cardiovascular diseases associated with impaired endothelial function. Aromatherapy is becoming popular as a complementary therapy that is beneficial for mental relaxation. The purpose of this study was to investigate the effect of aromatherapy on the endothelial function of medical staff after night-shift work. This study consisted of 19 healthy medical personnel (19 men, mean age 32 ± 7 years), including 11 physicians and 8 technicians. Aromatherapy was performed for 30 min by inhalation of the essential oil of lavender. Flow-mediated dilation (FMD) of the brachial artery was measured three times in each subject: on a regular workday, and after night-shift work before and immediately after aromatherapy. A control study was performed to assess the effect of a 30-min rest without aromatherapy. The mean value of sleep time during night-shift work was 3.3 ± 1.3 h. FMD after night-shift work was lower than on a regular workday (10.4 ± 1.8 vs. 12.5 ± 1.7%, P<0.001), which improved after aromatherapy (11.8 ± 2.5%, P=0.02 vs. before aromatherapy). FMD was stable in the control study (10.1 ± 1.9 vs. 10.1 ± 2.2%, P=0.9). This study demonstrated that night-shift work impaired endothelial function in medical staff, an effect that was alleviated by short-term aromatherapy.

The effects of shift work and time of day on fine motor control during handwriting.

PubMed

Hölzle, Patricia; Hermsdörfer, Joachim; Vetter, Céline

2014-01-01

Handwriting is an elaborate and highly automatised skill relying on fine motor control. In laboratory conditions handwriting kinematics are modulated by the time of day. This study investigated handwriting kinematics in a rotational shift system and assessed whether similar time of day fluctuations at the work place can be observed. Handwriting performance was measured in two tasks of different levels of complexity in 34 shift workers across morning (6:00-14:00), evening (14:00-22:00) and night shifts (22:00-6:00). Participants were tested during all three shifts in 2-h intervals with mobile testing devices. We calculated average velocity, script size and writing frequency to quantify handwriting kinematics and fluency. Average velocity and script size were significantly affected by the shift work schedule with the worst performance during morning shifts and the best performance during evening shifts. Our data are of high economic relevance as fine motor skills are indispensable for accurate and effective production at the work place. Handwriting is one of the most complex fine motor skills in humans, which is frequently performed in daily life. In this study, we tested handwriting repeatedly at the work place in a rotational shift system. We found slower handwriting velocity and reduced script size during morning shifts.

Systematic review: association of shift length, protected sleep time, and night float with patient care, residents' health, and education.

PubMed

Reed, Darcy A; Fletcher, Kathlyn E; Arora, Vineet M

2010-12-21

The Accreditation Council for Graduate Medical Education's new duty-hour standards limit interns' shifts to 16 hours and night float to 6 consecutive nights. Protected sleep time (that is, "nap") is strongly encouraged. As duty-hour reforms are implemented, examination of the quality and outcomes of the relevant literature is important. To systematically review the literature examining shift length, protected sleep time, and night float. MEDLINE, PREMEDLINE, and EMBASE from January 1989 through May 2010. Studies examined the associations of shift length, protected sleep time, or night float with patient care, resident health, and education outcomes among residents in practice settings. Study quality was measured by using the validated Medical Education Research Study Quality Instrument and the U.S. Preventive Services Task Force criteria. Two investigators independently rated study quality, and interrater agreement was calculated. Sixty-four studies met inclusion criteria. Most studies used single-group cross-sectional (19 studies [29.7%]) or pre-post (41 studies [64.1%]) designs, and 4 (6.3%) were randomized, controlled trials. Five studies (7.8%) were multi-institutional. Twenty-four of 33 (72.7%) studies examining shift length reported that shorter shifts were associated with decreased medical errors, motor vehicle crashes, and percutaneous injuries. Only 2 studies assessed protected sleep time and reported that residents' adherence to naps was poor. Night floats described in 33 studies involved 5 to 7 consecutive nights. Most studies used single-institution, observational designs. Publication bias is likely but difficult to assess in this methodologically weak and heterogeneous body of evidence. For the limited outcomes measured, most studies supported reducing shift length but did not adequately address the optimal shift duration. Studies had numerous methodological limitations and unclear generalizability for most outcomes. Specific recommendations about shift length, protected sleep time, and night float should acknowledge the limitations of this evidence. Accreditation Council for Graduate Medical Education.

Dark goggles and bright light improve circadian rhythm adaptation to night-shift work.

PubMed

Eastman, C I; Stewart, K T; Mahoney, M P; Liu, L; Fogg, L F

1994-09-01

We compared the contributions of bright light during the night shift and dark goggles during daylight for phase shifting the circadian rhythm of temperature to realign with a 12-hour shift of sleep. After 10 baseline days there were 8 night-work/day-sleep days. Temperature was continuously recorded from 50 subjects. There were four groups in a 2 x 2 design: light (bright, dim), goggles (yes, no). Subjects were exposed to bright light (about 5,000 lux) for 6 hours on the first 2 night shifts. Dim light was < 500 lux. Both bright light and goggles were significant factors for producing circadian rhythm phase shifts. The combination of bright light plus goggles was the most effective, whereas the combination of dim light and no goggles was the least effective. The temperature rhythm either phase advanced or phase delayed when it aligned with daytime sleep. However, when subjects did not have goggles only phase advances occurred. Goggles were necessary for producing phase delays. The most likely explanation is that daylight during the travel-home window after a night shift inhibits phase-delay shifts, and goggles can prevent this inhibition. Larger temperature-rhythm phase shifts were associated with better subjective daytime sleep, less subjective fatigue and better mood.

Violence and unsafety in a major Italian hospital: experience and perceptions of health care workers.

PubMed

Terzoni, S; Ferrara, P; Cornelli, R; Ricci, C; Oggioni, Chiara; Destrebecq, Anne

2015-11-22

Workers' experience of violence and perceived unsafety can have a profound impact on job satisfaction, job performance, and workers' decision to leave. The aim of the study was to assess the prevalence of physical and non-physical violence among hospital workers, explore the complaints and reactions of victims, assess the relationship between violence and psychosocial/work factors and analyze the levels of perceived unsafety. A cross-sectional study was conducted, via a structured self-administered questionnaire given to all the employees of a major hospital in Italy. Cronbach's alpha coefficient was used to assess the internal consistency of the questionnaire. A logistic regression model was used for data analysis. 903 questionnaires out of 1853 (48.7%) were correctly returned; 11.5% had experience of physical violence and 40.2% had been victims of verbal violence in the previous 12 months. The most common consequences were fear, anger, frustration, and anxiety. Verbal violence was influenced by age, role, department, night/holiday shift work and experience in the current ward. Experiences of physical violence were related to gender, role, and department; 469 responders (51.9%) reported feelings of unsafety, which were related to their professional role, department, shift work, experience of physical or psychological violence, having seen episodes of violence and having received specific training. Our findings suggest that several factors are associated with workplace violence in health care settings and some of these also influenced the levels of perceived unsafety.

Rotating night shift work, sleep quality, selected lifestyle factors and prolactin concentration in nurses and midwives.

PubMed

Bukowska, Agnieszka; Sobala, Wojciech; Peplonska, Beata

2015-04-01

The pattern of secretion of many hormones, including prolactin, is dependent on the circadian rhythm. Night shift work involves exposure to artificial light at night and sleep deficiency, which in turn can affect prolactin synthesis. The aim of this study was to evaluate a possible association between night shift work characteristics, sleep quality, lifestyle factors and prolactin concentration, using data from a cross-sectional study of nurses and midwives. A cross-sectional study was conducted among 327 nurses and midwives currently working on rotating night shifts, and 330 nurses and midwives working during the day (aged 40-60 years) (388 premenopausal and 269 postmenopausal). Information about night shift work characteristics, lifestyle, reproductive factors, sleep pattern and other covariates was collected through a face-to-face interview, and from a one-week work and sleep diary completed by the subjects. Weight and height were measured. Prolactin concentration was measured in the morning blood sample using the electrochemiluminesence immunoassay method. Associations were analyzed using linear regression models adjusted for important confounders. Analyses were carried out separately in pre- and postmenopausal women. None of the night shift work or sleep characteristics was significantly associated with prolactin concentration. Prolactin concentration was significantly (p < 0.05) inversely associated with smoking and time of blood sample collection. These results were consistent among both pre- and postmenopausal women. Nulliparity was significantly positively associated with prolactin among premenopausal women, but inversely among postmenopausal. Age was related to prolactin among postmenopausal women only. Our study indicates that rotating night shift work is not associated with prolactin concentration. Smoking, parity, time of blood collection and age among postmenopausal women were significant determinants of prolactin.

Estimating Time Physicians and Other Health Care Workers Spend with Patients in an Intensive Care Unit Using a Sensor Network.

PubMed

Butler, Rachel; Monsalve, Mauricio; Thomas, Geb W; Herman, Ted; Segre, Alberto M; Polgreen, Philip M; Suneja, Manish

2018-04-09

Time and motion studies have been used to investigate how much time various health care professionals spend with patients as opposed to performing other tasks. However, the majority of such studies are done in outpatient settings, and rely on surveys (which are subject to recall bias) or human observers (which are subject to observation bias). Our goal was to accurately measure the time physicians, nurses, and critical support staff in a medical intensive care unit spend in direct patient contact, using a novel method that does not rely on self-report or human observers. We used a network of stationary and wearable mote-based sensors to electronically record location and contacts among health care workers and patients under their care in a 20-bed intensive care unit for a 10-day period covering both day and night shifts. Location and contact data were used to classify the type of task being performed by health care workers. For physicians, 14.73% (17.96%) of their time in the unit during the day shift (night shift) was spent in patient rooms, compared with 40.63% (30.09%) spent in the physician work room; the remaining 44.64% (51.95%) of their time was spent elsewhere. For nurses, 32.97% (32.85%) of their time on unit was spent in patient rooms, with an additional 11.34% (11.79%) spent just outside patient rooms. They spent 11.58% (13.16%) of their time at the nurses' station and 23.89% (24.34%) elsewhere in the unit. From a patient's perspective, we found that care times, defined as time with at least one health care worker of a designated type in their intensive care unit room, were distributed as follows: 13.11% (9.90%) with physicians, 86.14% (88.15%) with nurses, and 8.14% (7.52%) with critical support staff (eg, respiratory therapists, pharmacists). Physicians, nurses, and critical support staff spend very little of their time in direct patient contact in an intensive care unit setting, similar to reported observations in both outpatient and inpatient settings. Not surprisingly, nurses spend far more time with patients than physicians. Additionally, physicians spend more than twice as much time in the physician work room (where electronic medical record review and documentation occurs) than the time they spend with all of their patients combined. Copyright © 2018 Elsevier Inc. All rights reserved.

The work compatibility improvement framework: an assessment of the worker-work environment interaction in the manufacturing sector.

PubMed

Genaidy, Ash M; Rinder, Magda M; A-Rehim, Amal D

2008-08-01

The manufacturing sector in the US is challenged by high health care costs and shortage of qualified workers, which are largely attributed to the degree of fit between the worker and work environment. In this regard, a healthy worker-work environment interface is a necessary and sufficient condition for the containment of health care costs and the retaining/attraction of highly qualified knowledge workers and should be based on the principles of optimum physical, cognitive and emotional health for the workers. In prior research, the Work Compatibility Improvement Framework (WCIF) was introduced as a vehicle to address these issues and was defined as the identification, improvement and maintenance of the well-being characteristics of the workforce and its interaction with the work environment through the application of engineering, medicine, management and human sciences methodologies, technologies and best practices. This paper advances WCIF by examining its applications in manufacturing with regard to the evaluation of working conditions impacting musculoskeletal/stress outcome measures. A study was conducted in a machining department of a bag packaging manufacturer in the Midwest of the United States. The work tasks were planned and executed with regard to the following aims: (1) to compute work compatibility as a function of work demands and energisers; (2) to establish whether the prevalence of musculoskeletal/stress disorders increases with a decrease in the quality of worker-work environment interface in terms of work compatibility level and other work factors such as shift and job category. A major finding is that a 'poor' work environment (a function of all work domains) results in musculoskeletal/stress disorders that are 105% and 67% higher than those for a 'good' work environment. The evening shift exhibited the poorest compatibility followed by the night shift relative to the day shift. Application of the work compatibility approach demonstrated the detection of non-added value work. It is essential to evaluate the various domains of worker-work environment interface to uncover the root causes that tend to sub-optimise the physical/cognitive/emotional health of the workforce. The WCIF was used to uncover the non-value added effort in the work process. These findings will have major implications for developing and implementing customised design interventions with the aim to maximise the benefit and reduce the cost of employees in a manufacturing enterprise. The study findings suggest that the WCIF should be pursued as a potential strategic tool for optimising human performance in an enterprise to create healthy workplaces.

Health effects of night shift duty on nurses in a university teaching hospital in Benin City, Nigeria.

PubMed

Isah, E C; Iyamu, O A; Imoudu, G O

2008-06-01

This study is aimed at identifying the effects of night shift duty on the health and wellbeing of nurses in order to make recommendations on ways of ameliorating them. The study was ofa cross sectional descriptive type using a total sample of nurses in the hospital. Data collection was by means of a semi-structured self-administered questionnaire and the analysis by the computer Programme for Epidemiologists (PEPI). The response rate was 79.3% with a total of 211 (68.1%) having one or more health complaints, which included muscle ache and pains (58.7%), frequent headaches (21.9%), lack of concentration (21.3%) and a negative effect on social life (66.1%). The younger nurses disliked night shift more than the older ones (2 = 57.5, df=6, p = 0.000) and 57.7% felt they were less productive during night shift. The shorter the period of sleep after the night shift, the lesser the level of productivity and the more the manifestation of health symptoms (2 = 45.5, df = 4, p = 0.000 and 2 = 29.0, df = 2, p = 0.000 respectively). Night shift duty caused both medical and psychological problems on the nurses. There is a need for medical surveillance, educational programme and the application of sleep hygiene techniques for shift working nurses.

Differences in day and night shift clinical performance in anesthesiology.

PubMed

Cao, Caroline G L; Weinger, Matthew B; Slagle, Jason; Zhou, Chuan; Ou, Jennie; Gillin, Shakha; Sheh, Bryant; Mazzei, William

2008-04-01

This study examined whether anesthesia residents (physicians in training) performed clinical duties in the operating room differently during the day versus at night. Fatigue from sleep deprivation and working through the night is common for physicians, particularly during residency training. Using a repeated-measures design, we studied 13 pairs of day-night matched anesthesia cases. Dependent measures included task times, workload ratings, response to an alarm light latency task, and mood. Residents spent significantly less time on manual tasks and more time on monitoring tasks during the maintenance phase at night than during the day. Residents reported more negative mood at night than during the day, both pre- and postoperation. However, time of day had no effect on the mood change between pre- and postoperation. Workload ratings and the response time to an alarm light latency task were not significantly different between night and day cases. Because night shift residents had been awake and working for more than 16 hr, the observed differences in task performance and mood may be attributed to fatigue. The changes in task distribution during night shift work may represent compensatory strategies to maintain patient care quality while keeping perceived workload at a manageable level. Fatigue effects during night shifts should be considered when designing work-rest schedules for clinicians. This matched-case control scheme can also be applied to study other phenomena associated with patient safety in the actual clinical environment.

Napping on the Night Shift: A Study of Sleep, Performance, and Learning in Physicians-in-Training

PubMed Central

McDonald, Jennifer; Potyk, Darryl; Fischer, David; Parmenter, Brett; Lillis, Teresa; Tompkins, Lindsey; Bowen, Angela; Grant, Devon; Lamp, Amanda; Belenky, Gregory

2013-01-01

Background Physicians in training experience fatigue from sleep loss, high workload, and working at an adverse phase of the circadian rhythm, which collectively degrades task performance and the ability to learn and remember. To minimize fatigue and sustain performance, learning, and memory, humans generally need 7 to 8 hours of sleep in every 24-hour period. Methods In a naturalistic, within-subjects design, we studied 17 first- and second-year internal medicine residents working in a tertiary care medical center, rotating between day shift and night float every 4 weeks. We studied each resident for 2 weeks while he/she worked the day shift and for 2 weeks while he/she worked the night float, objectively measuring sleep by wrist actigraphy, vigilance by the Psychomotor Vigilance Task test, and visual-spatial and verbal learning and memory by the Brief Visuospatial Memory Test-Revised and the Rey Auditory-Verbal Learning Test. Results Residents, whether working day shift or night float, slept approximately 7 hours in every 24-hour period. Residents, when working day shift, consolidated their sleep into 1 main sleep period at night. Residents working night float split their sleep, supplementing their truncated daytime sleep with nighttime on-duty naps. There was no difference in vigilance or learning and memory, whether residents worked day shift or night float. Conclusions Off-duty sleep supplemented with naps while on duty appears to be an effective strategy for sustaining vigilance, learning, and memory when working night float. PMID:24455014

A meta-analysis including dose-response relationship between night shift work and the risk of colorectal cancer

PubMed Central

Wang, Xiao; Ji, Alin; Zhu, Yi; Liang, Zhen; Wu, Jian; Li, Shiqi; Meng, Shuai; Zheng, Xiangyi; Xie, Liping

2015-01-01

A meta-analysis was conducted to quantitatively evaluate the correlation between night shift work and the risk of colorectal cancer. We searched for publications up to March 2015 using PubMed, Web of Science, Cochrane Library, EMBASE and the Chinese National Knowledge Infrastructure databases, and the references of the retrieved articles and relevant reviews were also checked. OR and 95% CI were used to assess the degree of the correlation between night shift work and risk of colorectal cancer via fixed- or random-effect models. A dose-response meta-analysis was performed as well. The pooled OR estimates of the included studies illustrated that night shift work was correlated with an increased risk of colorectal cancer (OR = 1.318, 95% CI 1.121–1.551). No evidence of publication bias was detected. In the dose-response analysis, the rate of colorectal cancer increased by 11% for every 5 years increased in night shift work (OR = 1.11, 95% CI 1.03–1.20). In conclusion, this meta-analysis indicated that night shift work was associated with an increased risk of colorectal cancer. Further researches should be conducted to confirm our findings and clarify the potential biological mechanisms. PMID:26208480

Trapezius Muscle Load, Heart Rate and Time Pressure during Day and Night Shift in Swiss and Japanese Nurses

PubMed Central

NICOLETTI, Corinne; MÜLLER, Christian; TOBITA, Itoko; NAKASEKO, Masaru; LÄUBLI, Thomas

2014-01-01

The aim of the present study was to analyze the activity of the trapezius muscle, the heart rate and the time pressure of Swiss and Japanese nurses during day and night shifts. The parameters were measured during a day and a night shift of 17 Swiss and 22 Japanese nurses. The observed rest time of the trapezius muscle was longer for Swiss than for Japanese nurses during both shifts. The 10th and the 50th percentile of the trapezius muscle activity showed a different effect for Swiss than for Japanese nurses. It was higher during the day shift of Swiss nurses and higher during the night shift of Japanese nurses. Heart rate was higher for both Swiss and Japanese nurses during the day. The time pressure was significantly higher for Japanese than for Swiss nurses. Over the duration of the shifts, time pressure increased for Japanese nurses and slightly decreased for those from Switzerland. Considering trapezius muscle activity and time pressure, the nursing profession was more burdening for the examined Japanese nurses than for Swiss nurses. In particular, the night shift for Japanese nurses was characterized by a high trapezius muscle activity and only few rest times for the trapezius muscle. PMID:24633074

Trapezius muscle load, heart rate and time pressure during day and night shift in Swiss and Japanese nurses.

PubMed

Nicoletti, Corinne; Müller, Christian; Tobita, Itoko; Nakaseko, Masaru; Läubli, Thomas

2014-01-01

The aim of the present study was to analyze the activity of the trapezius muscle, the heart rate and the time pressure of Swiss and Japanese nurses during day and night shifts. The parameters were measured during a day and a night shift of 17 Swiss and 22 Japanese nurses. The observed rest time of the trapezius muscle was longer for Swiss than for Japanese nurses during both shifts. The 10th and the 50th percentile of the trapezius muscle activity showed a different effect for Swiss than for Japanese nurses. It was higher during the day shift of Swiss nurses and higher during the night shift of Japanese nurses. Heart rate was higher for both Swiss and Japanese nurses during the day. The time pressure was significantly higher for Japanese than for Swiss nurses. Over the duration of the shifts, time pressure increased for Japanese nurses and slightly decreased for those from Switzerland. Considering trapezius muscle activity and time pressure, the nursing profession was more burdening for the examined Japanese nurses than for Swiss nurses. In particular, the night shift for Japanese nurses was characterized by a high trapezius muscle activity and only few rest times for the trapezius muscle.

The correlation between urinary 5-hydroxyindoleacetic acid and sperm quality in infertile men and rotating shift workers

PubMed Central

2010-01-01

Background Serotonin is a neurotransmitter that modulates a wide range of neuroendocrine functions. However, excessive circulating serotonin levels may induce harmful effects in the male reproductive system. The objective of this study was to evaluate whether the levels of urinary 5-hydroxyindoleacetic acid (5-HIIA), a major serotonin metabolite, correlate with different classical seminal parameters. Methods Human ejaculates were obtained from 40 men attending infertility counselling and rotating shift workers by masturbation after 4-5 days of abstinence. Urinary 5- HIIA concentration was quantified by using a commercial ELISA kit. Forward motility was assessed by a computer-aided semen analysis (CASA) system. Sperm concentration was determined using the haemocytometer method. Sperm morphology was evaluated after Diff-Quik staining, while sperm vitality was estimated after Eosin-Nigrosin vital staining. Results Our results show that urinary 5-HIIA levels obtained from a set of 20 volunteers negatively correlated with sperm concentration, forward motility, morphology normal range and sperm vitality. On the other hand, we checked the relationship between male infertility and urinary 5-HIIA levels in 20 night shift workers. Thus, urinary 5-HIIA levels obtained from 10 recently-proven fathers were significantly lower than those found in 10 infertile males. Additionally, samples from recent fathers exhibited higher sperm concentration, as well as better forward motility and normal morphology rate. Conclusions In the light of our findings, we concluded that high serotonin levels, indirectly measured as urinary 5-HIIA levels, appear to play a role as an infertility determinant in male subjects. PMID:21059225

Night Shift Work and Risk of Breast Cancer.

PubMed

Hansen, Johnni

2017-09-01

Night work is increasingly common and a necessity in certain sectors of the modern 24-h society. The embedded exposure to light-at-night, which suppresses the nocturnal hormone melatonin with oncostatic properties and circadian disruption, i.e., misalignment between internal and external night and between cells and organs, are suggested as main mechanisms involved in carcinogenesis. In 2007, the International Agency for Research on Cancer (IARC) classified shift work that involves circadian disruption as probably carcinogenic to humans based on limited evidence from eight epidemiologic studies on breast cancer, in addition to sufficient evidence from animal experiments. The aim of this review is a critical update of the IARC evaluation, including subsequent and the most recent epidemiologic evidence on breast cancer risk after night work. After 2007, in total nine new case-control studies, one case-cohort study, and eight cohort studies are published, which triples the number of studies. Further, two previous cohorts have been updated with extended follow-up. The assessment of night shift work is different in all of the 26 existing studies. There is some evidence that high number of consecutive night shifts has impact on the extent of circadian disruption, and thereby increased breast cancer risk, but this information is missing in almost all cohort studies. This in combination with short-term follow-up of aging cohorts may explain why some cohort studies may have null findings. The more recent case-control studies have contributed interesting results concerning breast cancer subtypes in relation to both menopausal status and different hormonal subtypes. The large differences in definitions of both exposure and outcome may contribute to the observed heterogeneity of results from studies of night work and breast cancer, which overall points in the direction of an increased breast cancer risk, in particular after over 20 years of night shifts. Overall, there is a tendency of increased risk of breast cancer either after over 20 years of night shift or after shorter periods with many consecutive shifts. More epidemiologic research using standardized definitions of night work metrics and breast cancer subtypes as well as other cancers is needed in order to improve the epidemiologic evidence in combination with animal models of night work. Also, evidence-based preventive interventions are needed.

Evaluation of oxidative stress parameters and metabolic activities of nurses working day and night shifts.

PubMed

Ulas, Turgay; Buyukhatipoglu, Hakan; Kirhan, Idris; Dal, Mehmet Sinan; Ulas, Sevilay; Demir, Mehmet Emin; Eren, Mehmet Ali; Ucar, Mehmet; Hazar, Abdussamet; Kurkcuoglu, Ibrahim Can; Aksoy, Nurten

2013-04-01

The aim of this study was to evaluate the oxidative stress and metabolic activities of nurses working day and night shifts. Intensive care unit (ICU) (n=70) and ordinary service (OS) nurses (n=70) were enrolled in the study. Just before and the end of the shifts, blood samples were obtained to measure the participants' oxidative stress parameters. Metabolic activities were analyzed using the SenseWear Armband. Oxidative stress parameters were increased at the end of the shifts for all OS and ICU nurses compared to the beginning of the shifts. Compared to the OS nurses, the ICU nurses' TAS, TOS, and OSI levels were not significantly different at the end of the day and night shifts. The metabolic activities of the OS and ICU nurses were found to be similar. As a result, the OS and ICU nurses' oxidative stress parameters and metabolic activities were not different, and all of the nurses experienced similar effects from both the day and night shifts.

Smoked marijuana attenuates performance and mood disruptions during simulated night shift work.

PubMed

Keith, Diana R; Gunderson, Erik W; Haney, Margaret; Foltin, Richard W; Hart, Carl L

2017-09-01

Individuals who work nonstandard schedules, such as rotating or night shifts, are more susceptible to workplace injuries, performance decrements, and reduced productivity. This population is also almost twice as likely to use illicit drugs as individuals working a standard day shift. The purpose of this study was to examine the effects of smoked marijuana on performance, mood, and sleep during simulated shift work. Ten experienced marijuana smokers completed this 23-day, within-participant residential study. They smoked a single marijuana cigarette (0, 1.9, 3.56% Δ 9 -THC) one hour after waking for three consecutive days under two shift conditions: day shift and night shift. Shifts alternated three times during the study, and shift conditions were separated by an 'off' day. When participants smoked placebo cigarettes, psychomotor performance and subjective-effect ratings were altered during the night shift compared to the day shift: performance (e.g., vigilance) and a few subjective ratings were decreased (e.g., "Self-Confident"), whereas other ratings were increased (e.g., "Tired"). Objective and subjective measures of sleep were also disrupted, but to a lesser extent. Marijuana attenuated some performance, mood, and sleep disruptions: participants performed better on vigilance tasks, reported being less miserable and tired and sleep a greater number of minutes. Limited negative effects of marijuana were noted. These data demonstrate that abrupt shift changes produce performance, mood, and sleep decrements during night shift work and that smoked marijuana containing low to moderate Δ 9 -THC concentrations can offset some of these effects in frequent marijuana smokers. Copyright © 2017 Elsevier B.V. All rights reserved.

The effect of day and night shifts on oxidative stress and anxiety symptoms of the nurses.

PubMed

Ulas, T; Buyukhatipoglu, H; Kirhan, I; Dal, M S; Eren, M A; Hazar, A; Demir, M E; Aydogan, T; Karababa, F; Uyanikoglu, A; Kurkcuoglu, I C

2012-05-01

Oxidative stress is believed to have a role in the development of chronic diseases. It is also known that long-term night and shift work in nurses might be associated with many health-related problems like fatigue, sleep problems, anxiety and difficulties in maintaining regular lifestyles. In this study, we aimed to evaluate the changes of oxidative stress parameters and anxiety indexes of the nurses on day and night shifts. One hundred and twenty nurses in ordinary service and intensive care unit (ICU) were enrolled to the study. Subjects were divided into 2 groups; group 1 (n = 60) consisted of nurses working in a day shift and group 2 (n = 60) as working in the night shift. Further, both groups were divided in to 2 groups again; group la and 2a (both n = 30) who working in the ICU, group 1b and 2b (both n = 30) in the ordinary service. Just before and the end of the shifts, blood samples were obtained to measure total antioxidant status (TAS) and total oxidant status (TOS). Oxidative stress index (OSI) was calculated. Anxiety index were determined at the end of the shift using State-Trait Anxiety Inventory index. Oxidative stress parameters were increased in all nurses at the end of the day and night shifts (p < 0.05). However, both in service and ICU nurses TAS, TOS, and OSI levels were not significantly different at the beginning and the end of the shifts (p > 0.05). Anxiety indexes of each ordinary service and ICU nurses were found to be similar (p > 0.05). Ordinary service and ICU nurses' oxidative stress parameters and anxiety indexes were not different and all nurses suffer the similar effects of the shifts both in day and night.

Effects of night shift working on some immunological, prostate specific antigen, cortisol level and malondialdehyde in male nurses at Hawler city

NASA Astrophysics Data System (ADS)

Muhammad, Dilshad Hussein; Qadir, Fikry Ali

2017-09-01

The present study was carried out to show the effects of nightshift working on some immunological, serum cortisol level, and malondialdehyde (MDA) on male nurses in Hawler city hospitals. After performing the exclusion and inclusion criteria, ninety-six male nurses were participated in this study. According to working shifts, the participants were divided into two groups. First group includes sixty seven night-shift male nurses working for 3-12 years with 8-10 nights/month. The second group consisted of twenty-nine day-shift male nurses working for 3-12 years. The age range of both groups was (≥20-40≤). The second group was used as a control group for statistical comparison. The results showed that night-shift working in male nurses was associated with significant increases in tumor necrosis factor-α (TNF-α) (77.15 ± 3.328 vs.101.1 ± 6.968, p=0.024), interleukin-2 (IL-2) (1147 ± 59.54vs1626 ± 34.71, p=0.001), and interferon-γ (IFN-γ) (272.3 ± 16.00 vs. 319.6 ± 12.48, p=0.029) when compared with day-shift group. Two-fold significant increase of high-sensitive C-reactive protein (hs-CRP) (3154 ± 403.3 vs. 6739 ± 334.0, p=0.001) was found in nightshift group as compared with day-shift group. Prostate specific antigen (PSA) estimation showed no significant increase in night-shift group in comparison with day-shift group (1.755 ± 0.202 vs. 1.987 ± 0.159, p=0.424). The results also showed that night-shift working was associated with significant elevations in serum cortisol levels when compared with dayshift nurses (7.844 ± 0.529 vs. 11.18 ± 0.406, p=0.001). Similar significant increasing was also observed for serum malondialdehyde (MDA) (1.124 ± 0.075 vs. 1.681 ± 0.079, p=0.001) in night-shift group when compared with day-shift group.

Cognitive consequences of sleep deprivation, shiftwork, and heat exposure for underground miners.

PubMed

Legault, Glenn; Clement, Alexandra; Kenny, Glen P; Hardcastle, Stephen; Keller, Nancy

2017-01-01

Sleep deprivation, abnormal sleep patterns arising from working rotating shifts, and exposure to high ambient temperatures contribute to physical and cognitive dysfunction. We examined the effects of these on 19 (41.5 ± 5.1 years) male underground miners. Data were collected for 28 to 30 consecutive days such that the participants experienced their full rotating shift schedule, including days off. Objective measures of sleep quality (actigraphy), attentional capacity (psychomotor vigilance task), core body temperature (visceral pill), executive function (BRIEF-A) and subjective measures of fatigue (Karolinska and Epworth Sleepiness scales) were obtained over the 28-30 day period. Non-parametric analyses (χ(2), Wilcoxen Signed ranks) were used to determine differences between shift types and days off. Z-tests were used to compare sample data to population norms. These revealed that the participants experienced poor quality of sleep relative to age-matched norms irrespective of the shift being worked or if the participant was on a scheduled day off [30-39 year olds: z = -14.62, p < 0.001; 40-49 year olds: z = -4.44, p < 0.001]. Participants when working day shift experienced less sleep prior to beginning work compared to their days off or night shift; however, no differences in total sleep time between when participants worked day or night shifts were observed [χ(2) (2, n = 18) = 13.44, p < 0.01]. When measured subjectively, the only time participants reported excessive sleepiness was after a night shift. Objective measures of attentional capacity showed best performance at the beginning of night shifts in contrast to any other time that the task was completed; however, performance degraded dramatically over the course of the night shift [χ(2) (2, n = 12) = 6.50, p < 0.05]. We show that underground miners reported for work sleep deprived. The cognitive consequences of this poor sleep were most pronounced during night shift when their attentional capacity declined rapidly over the course of the night shift. Copyright © 2016 Elsevier Ltd. All rights reserved.

Perceptions and observations of off-shift nursing.

PubMed

de Cordova, Pamela B; Phibbs, Ciaran S; Stone, Patricia W

2013-03-01

The purpose of this paper is to qualitatively explore registered nurse perceptions of off-shift (e.g. nights and weekends) nursing care and quality compared with regular hours. Patients admitted to hospitals on off-shifts have worse outcomes than patients admitted on more regular hours. The underlying mechanism for this association is not well understood. In-depth semi-structured interviews of 23 registered nurses and four observer-as-participant observations were conducted on both medical-surgical and intensive care units in two large (>850 beds) tertiary hospitals. Content analysis was used to identify themes. Six themes emerged: (1) collaboration among self-reliant night nurses; (2) completing tasks; (3) taking a breather on weekend day shift; (4) new nurse requirement to work at night; (5) mixture of registered nurse personnel; and (6) night nurse perception of under-appreciation. Although nurses collaborate, complete more tasks and work with other types of registered nurses, the decreased resources available on off-shifts may affect quality care delivered in hospitals. These findings support the importance of management to provide sufficient resources in terms of ancillary personnel and balance less experienced staff. Facilitating communication between night and day nurses may help allay night nurses' feelings of under-appreciation. © 2012 Blackwell Publishing Ltd.

Paradoxical post-exercise responses of acylated ghrelin and leptin during a simulated night-shift

PubMed Central

Morris, Chris; Fullick, Sarah; Gregson, Warren; Clarke, Neil; Doran, Dominic; MacLaren, Don; Atkinson, Greg

2009-01-01

Approximately 10% of employees undertake night-work which is a significant predictor of weight-gain, possibly because responses to activity and eating are altered at night. It is known that the appetite-related hormone, acylated ghrelin is suppressed after an acute bout of exercise during the day, but no researcher has explored whether evening exercise alters acylated ghrelin and other appetite-related outcomes during a subsequent night-shift. Six healthy men (mean±SD: age 30±8 yrs, body mass index 23.1±1.1 kg/m2) completed two crossover trials (control and exercise) in a random order. Participants fasted from 10:00 h, consumed a test meal at 18:00 h and then cycled at 50% peak oxygen uptake or rested between 19:00-20:00 h. Participants then completed light activities during a simulated night-shift which ended at 05:00 h. Two small isocaloric meals were consumed at 22:00 and 02:00 h. Venous blood samples were drawn via cannulation at 1-h intervals between 19:00-05:00 h for the determination of acylated ghrelin, leptin, insulin, glucose, triglyceride and non-esterified fatty acids concentrations. Perceived hunger and wrist actimetry were also recorded. During the night-shift, mean±SD acylated ghrelin concentration was 86.5±40.8 pg/ml following exercise compared with 71.7±37.7 pg/ml without prior exercise (P=0.015). Throughout the night-shift, leptin concentration was 263±242 pg/ml following exercise compared with 187±221 pg/ml without prior exercise (P=0.017). Mean levels of insulin, triglyceride, non-esterified fatty acids and wrist actimetry were also higher during the night-shift that followed exercise (P<0.05). These data indicate that prior exercise increases acylated ghrelin and leptin concentrations during a subsequent simulated night-shift. These findings differ from the known effects of exercise on acylated ghrelin and leptin during the day, and therefore have implications for energy balance during night-work. PMID:20524803

Melatonin treatment of pediatric residents for adaptation to night shift work.

PubMed

Cavallo, Anita; Ris, M Douglas; Succop, Paul; Jaskiewicz, Julie

2005-01-01

Night float rotations are used in residency training programs to reduce residents' sleep deprivation. Night shift work, however, is accompanied by deleterious effects on sleep, mood, and attention. To test whether melatonin reduces the deleterious effects of night shift work on sleep, mood, and attention in pediatric residents during night float rotation. Double-blind, randomized, placebo-controlled crossover. Participants took melatonin (3 mg) or a placebo before bedtime in the morning after night shift; completed a sleep diary and an adverse-effects questionnaire daily; and completed the Profile of Mood States and the Conners Continuous Performance Test 3 times in each study week to test mood and attention, respectively. A university-affiliated, tertiary-care pediatric hospital. Healthy second-year pediatric residents working 2 night float rotations. Standardized measures of sleep, mood, and attention. Twenty-eight residents completed both treatments; 17 completed 1 treatment (10 placebo, 7 melatonin). There was not a statistically significant difference in measures of sleep, mood, and 5 of 6 measures of attention during melatonin and placebo treatment. One measure of attention, the number of omission errors, was significantly lower on melatonin (3.0 +/- 9.6) than on placebo (4.5 +/- 17.5) (z = -2.12, P = .03). The isolated finding of improvement of 1 single measure of attention in a test situation during melatonin treatment was not sufficiently robust to demonstrate a beneficial effect of melatonin in the dose used. Other strategies need to be considered to help residents in adaptation to night shift work.

Effect of rotating shift work on childbearing and birth weight: a study of women working in a semiconductor manufacturing factory.

PubMed

Lin, Yu-Cheng; Chen, Mei-Huei; Hsieh, Chia-Jung; Chen, Pau-Chung

2011-05-01

Stable circadian rhythm is important for both maternal and fetal health. This retrospective analysis of women in a semiconductor factory evaluated the effect of shift work exposure on childbearing and birth weight. Records of 440 female employees (initial mean age: 28.4 years) including 111 mothers who had 158 live births during the period of observation (1997-2007) were reviewed. The data analyzed included maternal age, general health condition, highest educational level, life-style and occupational factors, as well as newborn gender, birth weight, birth order and gestational age. The childbearing rates of female workers on three different work schedules (consistent daytime work (CDW), intermittent (i-) or persistent (p-) rotating shift works (RSW)) were 32.1%, 20.0% and 25.4%, respectively (P=0.047). After controlling for potential confounding factors, childbearing rates among women with CDW exceeded those of shift workers (odds ratio (OR), 1.7; 95% confidence interval (CI), 1.0-3.0). The birth weights of newborns from mothers on the three work schedules (CDW, i-RSW and p-RSW) were significantly different (3271.7±395.4, 3251.3±460.9, and 2998.5±381.2 g, respectively (P<0.01). Newborns within the lightest birth weight quintile were significantly more likely to be born to mothers with exposure to p-RSW (OR, 4.3; 95% CI, 1.1-16.8). Rotating shift work exposure was significantly associated with decreased childbearing and lighter birth weight in women working in this semiconductor manufacturing factory. Work schedules should be carefully planned for female employees who are pregnant or preparing for pregnancy. Prenatal evaluations for mothers with persistent day-night rotating shift work exposures are especially necessary.

Night-shift work and breast cancer--a systematic review and meta-analysis.

PubMed

Ijaz, Sharea; Verbeek, Jos; Seidler, Andreas; Lindbohm, Marja-Liisa; Ojajärvi, Anneli; Orsini, Nicola; Costa, Giovanni; Neuvonen, Kaisa

2013-09-01

The aim of this review was to synthesize the evidence on the potential relationship between nightshift work and breast cancer. We searched multiple databases for studies comparing women in shift work to those with no-shift work reporting incidence of breast cancer. We calculated incremental risk ratios (RR) per five years of night-shift work and per 300 night shift increases in exposure and combined these in a random effects dose-response meta-analysis. We assessed study quality in ten domains of bias. We identified 16 studies: 12 case-control and 4 cohort studies. There was a 9% risk increase per five years of night-shift work exposure in case-control studies [RR 1.09, 95% confidence interval (95% CI) 1.02-1.20; I (2) = 37%, 9 studies], but not in cohort studies (RR 1.01, 95% CI 0.97-1.05; I (2) = 53%, 3 studies). Heterogeneity was significant overall (I (2) = 55%, 12 studies). Results for 300 night shifts were similar (RR 1.04, 95% CI 1.00-1.10; I (2) = 58%, 8 studies). Sensitivity analysis using exposure transformations such as cubic splines, a fixed-effect model, or including only better quality studies did not change the results. None of the 16 studies had a low risk of bias, and 6 studies had a moderate risk. Based on the low quality of exposure data and the difference in effect by study design, our findings indicate insufficient evidence for a link between night-shift work and breast cancer. Objective prospective exposure measurement is needed in future studies.

Overnight shift work: factors contributing to diagnostic discrepancies.

PubMed

Hanna, Tarek N; Loehfelm, Thomas; Khosa, Faisal; Rohatgi, Saurabh; Johnson, Jamlik-Omari

2016-02-01

The aims of the study are to identify factors contributing to preliminary interpretive discrepancies on overnight radiology resident shifts and apply this data in the context of known literature to draw parallels to attending overnight shift work schedules. Residents in one university-based training program provided preliminary interpretations of 18,488 overnight (11 pm–8 am) studies at a level 1 trauma center between July 1, 2013 and December 31, 2014. As part of their normal workflow and feedback, attendings scored the reports as major discrepancy, minor discrepancy, agree, and agree--good job. We retrospectively obtained the preliminary interpretation scores for each study. Total relative value units (RVUs) per shift were calculated as an indicator of overnight workload. The dataset was supplemented with information on trainee level, number of consecutive nights on night float, hour, modality, and per-shift RVU. The data were analyzed with proportional logistic regression and Fisher's exact test. There were 233 major discrepancies (1.26 %). Trainee level (senior vs. junior residents; 1.08 vs. 1.38 %; p < 0.05) and modality were significantly associated with performance. Increased workload affected more junior residents' performance, with R3 residents performing significantly worse on busier nights. Hour of the night was not significantly associated with performance, but there was a trend toward best performance at 2 am, with subsequent decreased accuracy throughout the remaining shift hours. Improved performance occurred after the first six night float shifts, presumably as residents acclimated to a night schedule. As overnight shift work schedules increase in popularity for residents and attendings, focused attention to factors impacting interpretative accuracy is warranted.

Analysis of polymorphisms in the circadian-related genes and breast cancer risk in Norwegian nurses working night shifts

PubMed Central

2013-01-01

Introduction Some studies have suggested that night work may be associated with an increased risk of breast cancer in nurses. We aimed to explore the role of circadian gene polymorphisms in the susceptibility to night work-related breast cancer risk. Methods We conducted a nested case-control study of Norwegian nurses comprising 563 breast cancer cases and 619 controls within a cohort of 49,402 Norwegian nurses ages 35 to 74 years. We studied 60 single-nucleotide polymorphisms (SNPs) in 17 genes involved in the regulation of the circadian rhythm in cases and controls. The data were analyzed in relation to the two exposure variables "maximum number of consecutive night shifts ever worked" and "maximum number of consecutive night shifts worked for at least 5 years." The odds of breast cancer associated with each SNP was calculated in the main effects analysis and in relation to night shift work. The statistically significant odds ratios were tested for noteworthiness using two Bayesian tests: false positive report probability (FPRP) and Bayesian false discovery probability (BFDP). Results In the main effects analysis, CC carriers of rs4238989 and GG carriers of rs3760138 in the AANAT gene had increased risk of breast cancer, whereas TT carriers of BMAL1 rs2278749 and TT carriers of CLOCK rs3749474 had reduced risk. The associations were found to be noteworthy using both the FPRP and BFDP tests. With regard to the effect of polymorphisms and night work, several significant associations were observed. After applying FPRP and BFDP in women with at least four night shifts, an increased risk of breast cancer was associated with variant alleles of SNPs in the genes AANAT (rs3760138, rs4238989), BMAL1 (rs2290035, rs2278749, rs969485) and ROR-b (rs3750420). In women with three consecutive night shifts, a reduced risk of breast cancer was associated with carriage of variant alleles of SNPs in CLOCK (rs3749474), BMAL1 (rs2278749), BMAL2 (rs2306074), CSNK1E (rs5757037), NPAS2 (rs17024926), ROR-b (rs3903529, rs3750420), MTNR1A (rs131113549) and PER3 (rs1012477). Conclusions Significant and noteworthy associations between several polymorphisms in circadian genes, night work and breast cancer risk were found among nurses who had worked at least three consecutive night shifts. PMID:23822714

Response to Dr Stevens' letter ref. Visitisen et al: "Short-term effects of night shift work on breast cancer risk: a cohort study of payroll data".

PubMed

Kolstad, Henrik A; Garde, Anne Helene; Hansen, Åse Marie; Frydenberg, Morten; Christiansen, Peer; Vistisen, Helene Tilma; Bonde, Jens Peter E

2017-01-01

We thank Dr Richard Stevens for his comments (1) on our recent article that showed no increased risk of breast cancer following recent night shift work when compared with recent day shift work (2). This finding was based on linkage of day-by-day information on working hours and breast cancer incidence data. Results are thus less likely to have been biased by differential misclassification than findings from earlier studies relying on self-report (3). We defined a night shift as ≥3 hours of work between 24:00-05:00 hours and a day shift as ≥3 hours work between 6:00-20:00 hours. This day shift definition did not exclude shifts starting before 05:00 or ending after 24:00 hours. However, this affected only 0.02% and 0.3% of all day shifts, respectively. This diminutive misclassification, that is expected to be non-differential, can hardly explain our negative findings. It is suggested that shifts that begin after 07:00 and end before 18:00 would constitute a more sensible baseline comparison group. Since the biological mechanism is not certain, it is not obvious to us if this will be a more appropriate reference than the present. However, we agree that future studies should test how different definitions of shifts affect the risk of breast cancer, which will be possible using this type of data. We only had information on working hours from 2007 and onwards, and night shift work prior to 2007 could have confounded our analyses towards no effect but only if inversely associated with night shift work in 2007 or later. We find this unlikely. Left truncation could also have biased findings towards the null. We therefore supplemented analyses of the total study population with analyses of the one-third of the population with first recorded employment in 2008 or later (the inception population). Even if the mean age was 35.5 years - and many undoubtedly had been working (with and without night shifts) prior to 2008 - this population should be less affected by such selection bias, but we observed similar risk estimates as for the total study population. Taken together, we find that our study provides rather robust evidence of no short-term breast cancer risk following recent night shift work. It must, however, be stressed that data did not allow assessment of a possible long-term risk. Reference 1. Stevens R. Letter ref. Vitisen et al: "Short-term effects of night shift work on breast cancer risk: a cohort study of payroll data". Scand J Work Environ Health. 2017;43(1):95. http://dx.doi.org/10.5271/sjweh.3607 2. Vistisen HT, Garde AH, Frydenberg M, Christiansen P, Hansen AM, Hansen J, Bonde JP, Kolstad HA. Short-term effects of night shift work on breast cancer risk: A cohort study of payroll data. Scand J Work Environ Health. 2017;43(1):59-67. http://dx.doi.org/10.5271/sjweh.3603. 3. Ijaz S, Verbeek J, Seidler A, Lindbohm ML, Ojajarvi A, Orsini N, Costa G, Neuvonen K. Night-shift work and breast cancer--a systematic review and meta-analysis. Scand J Work Environ Health. 2013 Sep 1;39(5):431-47. http://dx.doi.org/10.5271/sjweh.3371.

Night shift work and chronic lymphocytic leukemia in the MCC-Spain case-control study.

PubMed

Costas, Laura; Benavente, Yolanda; Olmedo-Requena, Rocío; Casabonne, Delphine; Robles, Claudia; Gonzalez-Barca, Eva-Maria; de la Banda, Esmeralda; Alonso, Esther; Aymerich, Marta; Tardón, Adonina; Marcos-Gragera, Rafael; Gimeno-Vázquez, Eva; Gómez-Acebo, Inés; Papantoniou, Kyriaki; Castaño-Vinyals, Gemma; Aragonés, Nuria; Pollán, Marina; Kogevinas, Manolis; de Sanjosé, Silvia

2016-11-01

Chronic lymphocytic leukemia (CLL) has few known modifiable risk factors. Recently, circadian disruption has been proposed as a potential contributor to lymphoid neoplasms' etiology. Serum melatonin levels have been found to be significantly lower in CLL subjects compared with healthy controls, and also, CLL prognosis has been related to alterations in the circadian molecular signaling. We performed the first investigation of an association between night shift work and CLL in 321 incident CLL cases and 1728 population-based controls in five areas of Spain. Participants were interviewed face-to-face by trained interviewers to collect information on sociodemographic factors, familial, medical and occupational history, including work shifts and other lifestyle factors. We used logistic regression models adjusted for potential confounders to estimate odds ratios (OR) and 95% confidence intervals (CI). Seventy-nine cases (25%) and 339 controls (20%) had performed night work. Overall, working in night shifts was not associated with CLL (OR = 1.06; 95% CI = 0.78-1.45, compared with day work). However, long-term night shift (>20 years) was positively associated with CLL (OR(tertile 3 vs . day-work)  = 1.77; 95% = 1.14-2.74), although no linear trend was observed (P trend = 0.18). This association was observed among those with rotating (OR(tertile 3 vs . day-work)  = 2.29; 95% CI = 1.33-3.92; P trend = 0.07), but not permanent night shifts (OR(tertile 3 vs . day-work) = 1.16; 95% CI = 0.60-2.25; P trend = 0.86). The association between CLL and long-term rotating night shift warrants further investigation. © 2016 UICC.

Night shift decreases cognitive performance of ICU physicians.

PubMed

Maltese, François; Adda, Mélanie; Bablon, Amandine; Hraeich, Sami; Guervilly, Christophe; Lehingue, Samuel; Wiramus, Sandrine; Leone, Marc; Martin, Claude; Vialet, Renaud; Thirion, Xavier; Roch, Antoine; Forel, Jean-Marie; Papazian, Laurent

2016-03-01

The relationship between tiredness and the risk of medical errors is now commonly accepted. The main objective of this study was to assess the impact of an intensive care unit (ICU) night shift on the cognitive performance of a group of intensivists. The influence of professional experience and the amount of sleep on cognitive performance was also investigated. A total of 51 intensivists from three ICUs (24 seniors and 27 residents) were included. The study participants were evaluated after a night of rest and after a night shift according to a randomized order. Four cognitive skills were tested according to the Wechsler Adult Intelligence Scale and the Wisconsin Card Sorting Test. All cognitive abilities worsened after a night shift: working memory capacity (11.3 ± 0.3 vs. 9.4 ± 0.3; p < 0.001), speed of processing information (13.5 ± 0.4 vs. 10.9 ± 0.3; p < 0.001), perceptual reasoning (10.6 ± 0.3 vs. 9.3 ± 0.3; p < 0.002), and cognitive flexibility (41.2 ± 1.2 vs. 44.2 ± 1.3; p = 0.063). There was no significant difference in terms of level of cognitive impairment between the residents and ICU physicians. Only cognitive flexibility appeared to be restored after 2 h of sleep. The other three cognitive skills were altered, regardless of the amount of sleep during the night shift. The cognitive abilities of intensivists were significantly altered following a night shift in the ICU, regardless of either the amount of professional experience or the duration of sleep during the shift. The consequences for patients' safety and physicians' health should be further evaluated.

Equity and working time: a challenge to achieve.

PubMed

Fischer, Frida Marina; Rotenberg, Lúcia; de Castro Moreno, Claudia Roberta

2004-01-01

Equity is a humanitarian issue that gained strength during the transition from the 20th to the 21st century due to the mounting global discussion and social crisis involving human rights, health, and work. This article aims at (1) introducing the concept of equity as it applies to work environments, particularly to situations involving demanding work schedules, (2) discussing the role of science in equity issues related to work, (3) introducing a new scientific society dedicated to working-time issues, and (4) presenting an overview of new research on working time and health as addressed by the series of manuscripts published in this special issue of Chronobiology International devoted to the XVIth International Symposium on Night and Shiftwork, held in Santos, Brazil, November 2003. The concept of equity has a political as a well as a scientific dimension. Many worldwide organizations, e.g., civil society, academia, and occupational health research institutions, advocate prompt actions toward equity as a strategy to attain sustainable development and to reduce poverty. The analyses of current tendencies in work settings reveal a general situation of disrespect for equity principles, which is expressed by heavy workloads, long work hours, poor work conditions, and deregulation of established labor laws, mainly in (but not restricted to) developing countries. In spite of the great contribution of science in the past five decades, obstacles stand in the way of effectively improving good working conditions, particularly in times of precarious employment. The Working Time Society is a new scientific society that aims at promoting research into working time and health and offers practical advice on how to minimize adverse effects of working hours on workers' health and well-being. An updated view of the research on working times and health includes studies on the relationship between work schedules, worker health, and well-being; effects of night and shiftwork on the internal synchronization of circadian rhythms and laboratory and field interventions; new methods of investigation or new approaches in shift-work studies; and prediction of risks in night and shift work. Current tendencies of work organization contribute to the amplification of inequality across groups and populations, revealing that equity remains a challenge to achieve.

Prevalence and correlates of drink driving within patrons of Australian night-time entertainment precincts.

PubMed

Curtis, Ashlee; Coomber, Kerri; Hyder, Shannon; Droste, Nic; Pennay, Amy; Jenkinson, Rebecca; Mayshak, Richelle; Miller, Peter G

2016-10-01

Drink driving is a significant public health concern, and contributes to many road fatalities worldwide. The current study is the first to examine the prevalence and correlates of drink driving behavior in a sample of night-time entertainment precinct attendees in Australia. Interviews were conducted with 4214 night-time entertainment precinct attendees in two metropolitan and three regional cities in Australia. Seven correlates of self-reported drink driving were examined: gender, age, occupation, blood alcohol concentration (BAC), alcohol consumed prior to attending a licensed venue, energy drink consumption, and other drug consumption. Fourteen percent of night-time entertainment precinct attendees reported drink driving in the past three months. Bivariate logistic regression models indicated that males were significantly more likely than females to report drink driving in the past three months. Blue-collar workers and sales/clerical/administrative workers were significantly more likely to report drink driving behavior in the past three months than white-collar workers. The likelihood of reporting drink driving during the three months prior to interview significantly increased as BAC on the current night out increased, and when patrons reported engaging in pre-drinking or other drug use. The multivariate model presented a similar pattern of results, however BAC and pre-drinking on the night of the interview were no longer independent significant predictors. Males, blue collar/sales/clerical/administrative workers, and illicit drug consumers were more likely to report engaging in drink driving behavior than their counterparts. Interventions should focus on addressing the considerable proportion night-time entertainment precinct attendees who report engaging in drink driving behavior. Copyright © 2016 Elsevier Ltd. All rights reserved.

Polysomnographic Technology

MedlinePlus

... a center, but most of the polysomnographic technologists’ work is done at night. Typical shifts are three to four ten to twelve hour shifts per week. The recommended workload is two patients per night. ...

Magnitude and risk factors of injuries in a glass bottle manufacturing plant.

PubMed

Bazroy, Joy; Roy, Gautam; Sahai, Ajit; Soudarssanane, M B

2003-01-01

A study was conducted in a glass bottle manufacturing plant in Pondicherry, India, to assess the magnitude and identify the risk factors of work-related injuries between January and December 1998. Three hundred and seventy-seven injuries were reported among 341 permanent workers followed up for one year (incidence=1,105.5/1,000 workers/yr). A higher load of injuries was noted in the first half of the night shifts and the second half of the other three shifts. Injuries were higher in the second half of the week and during the first half of the year. Hands and wrists were the most common sites of injury (40.6%), whereas the eye, foot, ankles and other body parts had 30%, 14.6%, 10.6% and 4.2% of injuries respectively. The commonest type of injury was cuts and lacerations (50.1%); injuries to the eye (due to foreign bodies, chemicals and welding sparks) accounted for 30%, sprains 8% and burns 7.1% of the injuries. A cohort of 75 workers chosen from the 341 permanent workers were followed up for the one year for identification of risk factors. Significant risk factors were age (less than 30 yr) and experience (less than 2 yr). Technical factors responsible for injury were a hazardous worksite in 37 (38.5%) cases, inadequate protection with safety wear in 32 (33%) cases and proximity to machines in 14 (14.6%) cases. Human factors identified were non-use of protective wear in 43 (45%), overconfidence in 18 (18.7%) and timing error while working with machines in 11 (11.4%) episodes.

Shift work, light at night, and the risk of breast cancer.

PubMed

Reed, Virginia A

2011-01-01

Studies of the effect of shift work have identified several negative health outcomes, most notably breast cancer. Disruption of circadian rhythm by exposure to light at night has been identified as the mechanism likely responsible for this outcome. This article recommends that health care institutions work with occupational health nurses to develop and implement hazard communication and policies concerning shift work, exposure to light at night, and increased risk for negative health outcomes, particularly breast cancer. 2011, SLACK Incorporated.

Treatment of shift work disorder and jet lag.

PubMed

Zee, Phyllis C; Goldstein, Cathy A

2010-09-01

With the growth of the 24-hour global marketplace, a substantial proportion of workers are engaged in nontraditional work schedules and frequent jet travel across multiple time zones. Thus, shift work disorder and jet lag are prevalent in our 24/7 society and have been associated with significant health and safety repercussions. In both disorders, treatment strategies are based on promoting good sleep hygiene, improving circadian alignment, and targeting specific symptoms.Treatment of shift work must be tailored to the type of shift. For a night worker, circadian alignment can be achieved with bright light exposure during the shift and avoidance of bright light (with dark or amber sunglasses) toward the latter portion of the work period and during the morning commute home. If insomnia and/or excessive sleepiness are prominent complaints despite behavioral approaches and adequate opportunity for sleep, melatonin may be administered prior to the day sleep period to improve sleep, and alertness during work can be augmented by caffeine and wake-promoting agents.For jet lag, circadian adaptation is suggested only for travel greater than 48 h, with travel east more challenging than travel west. Although advancing sleep and wake times and circadian timing for eastward travel with evening melatonin and morning bright light several days prior to departure can help avoid jet lag at the new destination, this approach may be impractical for many people, Therefore, strategies for treatment at the destination, such as avoidance of early morning light and exposure to late-morning and afternoon light alone or in conjunction with bedtime melatonin, can accelerate re-entrainment following eastward travel. For westward travel, a circadian delay can be achieved after arrival with afternoon and early-evening light with bedtime melatonin.Good sleep hygiene practices, together with the application of circadian principles, can improve sleep quality, alertness, performance, and safety in shift workers and jet travelers. However, definitive multicenter randomized controlled clinical trials are still needed, using traditional efficacy outcomes such as sleep and performance as well as novel biomarkers of health.

Night shift work and breast cancer risk: what do the meta-analyses tell us?

PubMed

Pahwa, Manisha; Labrèche, France; Demers, Paul A

2018-05-22

Objectives This paper aims to compare results, assess the quality, and discuss the implications of recently published meta-analyses of night shift work and breast cancer risk. Methods A comprehensive search was conducted for meta-analyses published from 2007-2017 that included at least one pooled effect size (ES) for breast cancer associated with any night shift work exposure metric and were accompanied by a systematic literature review. Pooled ES from each meta-analysis were ascertained with a focus on ever/never exposure associations. Assessments of heterogeneity and publication bias were also extracted. The AMSTAR 2 checklist was used to evaluate quality. Results Seven meta-analyses, published from 2013-2016, collectively included 30 cohort and case-control studies spanning 1996-2016. Five meta-analyses reported pooled ES for ever/never night shift work exposure; these ranged from 0.99 [95% confidence interval (CI) 0.95-1.03, N=10 cohort studies) to 1.40 (95% CI 1.13-1.73, N=9 high quality studies). Estimates for duration, frequency, and cumulative night shift work exposure were scant and mostly not statistically significant. Meta-analyses of cohort, Asian, and more fully-adjusted studies generally resulted in lower pooled ES than case-control, European, American, or minimally-adjusted studies. Most reported statistically significant between-study heterogeneity. Publication bias was not evident in any of the meta-analyses. Only one meta-analysis was strong in critical quality domains. Conclusions Fairly consistent elevated pooled ES were found for ever/never night shift work and breast cancer risk, but results for other shift work exposure metrics were inconclusive. Future evaluations of shift work should incorporate high quality meta-analyses that better appraise individual study quality.

Associations Among Rotating Night Shift Work, Sleep, and Skin Cancer in Nurses’ Health Study II Participants

PubMed Central

Heckman, Carolyn J.; Kloss, Jacqueline D.; Feskanich, Diane; Culnan, Elizabeth; Schernhammer, Eva S.

2016-01-01

Background Night shift work and sleep duration have been associated with breast and other cancers. Results from the few prior studies of night shift work and skin cancer risk have been mixed and not fully accounted for other potentially important health-related variables (e.g., sleep characteristics). This study evaluated the relationship between rotating night shift work and skin cancer risk and included additional skin cancer risk factors and sleep-related variables. Methods The current study used data from 74,323 Nurses’ Health Study (NHS) II participants. Cox proportional hazards models were used to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for skin cancers across categories of shift work and sleep duration. Results Over 10 years of follow-up, 4308 BCC, 334 SCC and 212 melanoma cases were identified. Longer duration of rotating night shifts was associated with a linear decline in risk of BCC (HR=0.93, 95% CI: 0.90-0.97 per 5-year increase). Shift work was not significantly associated with either melanoma (HR=1.02, 95% CI: 0.86-1.21) or SCC (HR=0.92, 95% CI: 0.80-1.06). A short sleep duration (≤6 hours per day) was associated with lower risks of melanoma (HR=0.68, 95% CI: 0.46-0.98) and BCC (HR=0.93, 95% CI: 0.86-1.00) compared with the most common report of 7 hours. SCC was not associated with duration of sleep (HR=0.94, 95% CI: 0.83-1.06). Conclusions Longer duration of rotating night shift work and shorter sleep duration were associated with lower risk of some skin cancers. Further research is needed to confirm and identify the mechanisms underlying these associations. PMID:27663986

Night shift preparation, performance, and perception: are there differences between emergency medicine nurses, residents, and faculty?

PubMed

Richards, John R; Stayton, Taylor L; Wells, Jason A; Parikh, Aman K; Laurin, Erik G

2018-04-30

Determine differences between faculty, residents, and nurses regarding night shift preparation, performance, recovery, and perception of emotional and physical health effects. Survey study performed at an urban university medical center emergency department with an accredited residency program in emergency medicine. Forty-seven faculty, 37 residents, and 90 nurses completed the survey. There was no difference in use of physical sleep aids between groups, except nurses utilized blackout curtains more (69%) than residents (60%) and faculty (45%). Bedroom temperature preference was similar. The routine use of pharmacologic sleep aids differed: nurses and residents (both 38%) compared to faculty (13%). Residents routinely used melatonin more (79%) than did faculty (33%) and nurses (38%). Faculty preferred not to eat (45%), whereas residents (24%) preferred a full meal. The majority (>72%) in all groups drank coffee before their night shift and reported feeling tired despite their routine, with 4:00 a.m. as median nadir. Faculty reported a higher rate (41%) of falling asleep while driving compared to residents (14%) and nurses (32%), but the accident rate (3% to 6%) did not differ significantly. All had similar opinions regarding night shift-associated health effects. However, faculty reported lower level of satisfaction working night shifts, whereas nurses agreed less than the other groups regarding increased risk of drug and alcohol dependence. Faculty, residents, and nurses shared many characteristics. Faculty tended to not use pharmacologic sleep aids, not eat before their shift, fall asleep at a higher rate while driving home, and enjoy night shift work less.

Circadian Adaptation to Night Shift Work Influences Sleep, Performance, Mood and the Autonomic Modulation of the Heart

PubMed Central

Boudreau, Philippe; Dumont, Guy A.; Boivin, Diane B.

2013-01-01

Our aim was to investigate how circadian adaptation to night shift work affects psychomotor performance, sleep, subjective alertness and mood, melatonin levels, and heart rate variability (HRV). Fifteen healthy police officers on patrol working rotating shifts participated to a bright light intervention study with 2 participants studied under two conditions. The participants entered the laboratory for 48 h before and after a series of 7 consecutive night shifts in the field. The nighttime and daytime sleep periods were scheduled during the first and second laboratory visit, respectively. The subjects were considered “adapted” to night shifts if their peak salivary melatonin occurred during their daytime sleep period during the second visit. The sleep duration and quality were comparable between laboratory visits in the adapted group, whereas they were reduced during visit 2 in the non-adapted group. Reaction speed was higher at the end of the waking period during the second laboratory visit in the adapted compared to the non-adapted group. Sleep onset latency (SOL) and subjective mood levels were significantly reduced and the LF∶HF ratio during daytime sleep was significantly increased in the non-adapted group compared to the adapted group. Circadian adaptation to night shift work led to better performance, alertness and mood levels, longer daytime sleep, and lower sympathetic dominance during daytime sleep. These results suggest that the degree of circadian adaptation to night shift work is associated to different health indices. Longitudinal studies are required to investigate long-term clinical implications of circadian misalignment to atypical work schedules. PMID:23923024

Evaluating the traditional day and night shift in an acute care surgery fellowship: Is the swing shift a better choice?

PubMed

Chestovich, Paul J; McNicoll, Christopher F; Ingalls, Nichole K; Kuhls, Deborah A; Fraser, Douglas R; Morrissey, Shawna L; Fildes, John J

2018-01-01

Fellowship trainees in acute care surgery require experience in the management of complex and operative trauma cases. Trauma center staffing usually follows standard 12-hour or 24-hour shifts, with resident and fellow trainees following a similar schedule. Although trauma admissions can be generally unpredictable, we analyzed temporal trends of trauma patient arrival times to determine the best time frame to maximize trainee experience during each day. We reviewed 10 years (2007-2016) of trauma registry data for blunt and penetrating trauma activations. Hourly volumetric trends were observed, and three specific events were chosen for detailed analysis: (1) trauma activation with Injury Severity Score (ISS) greater than 15, (2) laparotomy for trauma, and (3) thoracotomy for trauma. A retrospective shift log was created, which included day (7:00 AM to 7:00 PM), night (7:00 PM to 7:00 AM), and swing (noon to midnight) shifts. A swing shift was chosen because it captures the peak volume for all three events. Means and 95% confidence intervals were calculated, and comparisons were made between shifts using the Wilcoxon matched-pairs signed rank test with Bonferroni correction, and p less than 0.05 considered significant. During the 10-year study period, 28,287 patients were treated at our trauma center. This included the evaluation and management of 7,874 patients with ISS greater than 15, performance of 1,766 laparotomies, and 392 thoracotomies for trauma. Swing shift was superior to both day and night shifts for ISS greater than 15 (p < 0.001). Both swing and night shifts were superior to day shift for laparotomies (p < 0.001). Swing shift was superior to both day shift (p < 0.001) and night shift (p = 0.031). Shifts with the highest yield of ISS greater than 15, laparotomies, and thoracotomies include night and swing shifts on Fridays and Saturdays. Projected experience of acute care surgery fellows in managing complex trauma patients increases with the integration of swing shifts into the schedule. Daily trauma volume follows a temporal pattern which, when used correctly, can increase trainee exposure to complex and operative trauma cases. We encourage other centers to analyze their volume and adjust trainee schedules accordingly to maximize their educational experience. Therapeutic study, level IV.

Influence of flexibility and variability of working hours on health and well-being.

PubMed

Costa, Giovanni; Sartori, Samantha; Akerstedt, Torbjorn

2006-01-01

Flexible working hours can have several meanings and can be arranged in a number of ways to suit the worker and/or employer. Two aspects of "flexible" arrangement of working hours were considered: one more subjected to company control and decision (variability) and one more connected to individual discretion and autonomy (flexibility). The aim of the study was to analyze these two dimensions in relation to health and well-being, taking into consideration the interaction with some relevant background variables related to demographics plus working and social conditions. The dataset of the Third European Survey on working conditions, conducted in 2000 and involving 21,505 workers, was used. Nineteen health disorders and four psycho-social conditions were tested by means of multiple logistic regression analysis, in which mutually adjusted odds ratios were calculated for age, gender, marital status, number of children, occupation, mode of employment, shift work, night work, time pressure, mental and physical workload, job satisfaction, and participation in work organization. The flexibility and variability of working hours appeared inversely related to health and psycho-social well-being: the most favorable effects were associated with higher flexibility and lower variability. The analysis of the interactions with the twelve intervening variables showed that physical work, age, and flexibility are the three most important factors affecting health and well-being. Flexibility resulted as the most important factor to influence work satisfaction; the second to affect family and social commitment and the ability to do the same job when 60 years old, as well as trauma, overall fatigue, irritability, and headache; and the third to influence heart disease, stomachache, anxiety, injury, and the feeling that health being at risk because of work. Variability was the third most important factor influencing family and social commitments. Moreover, shift and night work confirmed to have a significant influence on sleep, digestive and cardiovascular troubles, as well and health and safety at work. Time pressure also showed a relevant influence, both on individual stress and social life. Therefore, suitable arrangements of flexible working time, aimed at supporting workers' coping strategies, appear to have a clear beneficial effect on worker health and well-being, with positive consequences also at the company and social level, as evidenced by the higher "feeling to be able to work until 60 years of age".

Motivation or demotivation of health workers providing maternal health services in rural areas in Vietnam: findings from a mixed-methods study.

PubMed

Thu, Nguyen Thi Hoai; Wilson, Andrew; McDonald, Fiona

2015-12-02

Motivation is an important driver for health professionals to maintain their professional competencies, continue in the workforce and make a positive contribution to their workplace. While there is some research about the motivation of health workers in low- to middle-income countries, maternal morbidity and mortality remains high and this can be lowered by improving the quality of maternal health services and the training and maintenance of the skills of maternal health workers. This study examines the impact of motivation on maintenance of professional competence among maternal health workers in Vietnam using mixed methods. The study consisted of a survey using a self-administered questionnaire of 240 health workers in five districts across two Vietnamese provinces and in-depth interviews with 43 health workers and health managers at the commune, district and provincial level to explore external factors that influenced motivation. The questionnaire includes a 23-item motivation instrument based on the Kenyan health context, modified for Vietnamese language and culture. The 240 responses represented an estimated 95% of the target sample. Multivariate analysis showed that three factors contributed to the motivation of health workers: access to training (β = -0.14, P = 0.03), ability to perform key tasks (β = 0.22, P = 0.001) and shift schedule (β = -0.13, P = 0.05). Motivation was higher in health workers self-identifying as competent or who were enabled to provide more maternal care services. Motivation was lower in those who worked more frequent night shifts and those who had received training in the last 12 months. The interviews identified that the latter was because they felt the training was irrelevant to them, and in some cases, they do not have the opportunity to practice their learnt skills. The qualitative data also showed other factors relating to service context and organisational management practices contributed to motivation. The study demonstrates the importance of understanding the motivations of health workers and the factors that contribute to this and may contribute to more effective management of the health workforce in low- and middle-income countries.

Effects of night shift on the cognitive load of physicians and urinary steroid hormone profiles - a randomized crossover trial.

PubMed

Osterode, Wolf; Schranz, Sandra; Jordakieva, Galateja

2018-03-21

Mental and physical stress is common in physicians during night shifts. Neurocognitive effects of sleep deprivation as well as alterations in hormonal and metabolic parameters have previously been described. The aim of this crossover study was to evaluate the effects of night-shift work with partial sleep deprivation on steroid hormone excretion and possible associations with mood, sleep characteristics and cognitive functions in physicians. In total, 34 physicians (mean age 42 ± 8.5 years, 76.5% male) from different departments of the General Hospital of Vienna, Austria, were randomly assigned to two conditions: a regular day shift (8 h on duty, condition 1) and a continuous day-night shift (24 h on duty, condition 2). In both conditions, physicians collected a 24 h urine sample for steroid hormone concentration analysis and further completed psychological tests, including the sleep questionnaire (SF-A), the questionnaire for mental state (MDBF) and the computer-assisted visual memory test (FVW) before and at the end of their shifts, respectively. Although mean sleep deprivation during night shift was relatively small (~1.5 h) the impairment in participants' mental state was high in all three dimensions (mood, vigilance and agitation, p ≤ 0.001). Sleep quality (SQ), feeling of being recovered after sleep and mental balance decreased (p ≤ 0.001), whereas mental exhaustion increased (p < 0.05). Moreover, we could show a nearly linear relationship between most of these self-rating items. Testing visual memory participants made significantly more mistakes after night shift (p = 0.011), however, mostly in incorrectly identified items and not in correctly identified ones (FVW). SQ and false identified items were negatively correlated, whereas SQ and time of reaction were positively associated. It is assumed that after night shift, a tendency exists to make faster wrong decisions. SQ did not influence correctly identified items in FVW. In contrast to previous investigations, we found that only excretion rates for pregnanetriol and androsterone/etiocholanolone ratios (p < 0.05, respectively) were slightly reduced in 24-h urine samples after night shift. A considerable stimulation of the adrenocortical axis could not be affirmed. In general, dehydroepiandrosteron (DHEA) was negatively associated with the sense of recreation after sleep and with the time of reaction and positively correlated with correctly identified items in the FVW test. These results, on the one hand, are in line with previous findings indicating that stress and sleep deprivation suppress gonadal steroids, but, on the other hand, do not imply significant adrenocortical-axis stimulation (e.g. an increase of cortisol) during the day-night shift.

[Protocols for the health surveillance of fisherman].

PubMed

Soleo, Leonardo; Cannizzaro, Emanuele; Lovreglio, Piero; Basso, Antonella; D'Errico, Maria Nicolà; Pira, Enrico

2013-01-01

To define protocols for health surveillance of workers in the marine fishing sector for specific occupational risk factors, considering the latest and most advanced scientific knowledge. The specific literature was analyzed to identify the occupational risk factors to which fishermen are exposed. Then, for each risk factor a protocol for the relative health checkups and their time schedule was defined. The risk factors to which fishermen are exposed are essentially noise, vibrations, solar and ultraviolet radiation, climatic agents (heat, cold, wind, rain, damp), chemical agents, shifts, work rate, night work, physical strain, stress, manual handling of loads, upper limb repetitive tasks, incongruous postures. The health protocols stipulate the health screening investigations to be carried out in all workers of a homogeneous group, and in-depth diagnostic investigations to be carried out in symptomatic workers. Complementary health investigations must be focused on a functional exploration of the organs specifically exposed to the risk factor. For hearing impairments due to noise exposure, the medico-legal measures with which the occupational health physician must comply, in cases of occupational disease, are indicated.

Health consequences of shift-work: the case of iranian hospital security personnel.

PubMed

Abedini, Roghayeh; Soltanzadeh, Ahmad; Faghih, Mohammad Amin; Mohammadi, Heidar; Kamalinia, Mojtaba; Mohraz, Majid Habibi; Arassi, Maziyar; Veyseh, Peyman Piran; Aghaei, Hamed; Hosseini, Seyed Younes

2015-01-01

Shift-work, which is an ergonomics issue in workplaces, can negatively affect workers. The security personnel of medical centers in Iran have multiple responsibilities and consequently are exposed to such unwanted situations as observing patients, disputing with patient's attendants, unwanted shift schedules, and being away from family for long periods. This study assessed health problems of Iranian hospital security personnel (shift-worker personnel) using the Survey of Shift-workers (SOS) questionnaire (Persian version). This cross-sectional study was conducted in seven medical centers (4 hospitals and 3 clinics). A total of 416 workers were surveyed: shift-workers (exposed group) (n=209) and non-shift-workers (unexposed group) (n=207). The prevalence of adverse health effects was higher in shift-workers than day-workers. The level of education and mean Body Mass Index (BMI) in shift-workers were significantly higher compared with day-workers. The prevalence of gastrointestinal disorders, cardiovascular and psychological problems were also significantly higher in shift-workers compared with day-workers. Overall, the prevalence of health problems among the security personnel of medical centers was high. Hence, it is recommended that personnel be put under periodic monitoring and receive medical counseling and treatment if there is any disorder.

Shift work and work injury in the New Zealand Blood Donors' Health Study.

PubMed

Fransen, M; Wilsmore, B; Winstanley, J; Woodward, M; Grunstein, R; Ameratunga, S; Norton, R

2006-05-01

To investigate associations between work patterns and the occurrence of work injury. A cross sectional analysis of the New Zealand Blood Donors Health Study conducted among the 15 687 (70%) participants who reported being in paid employment. After measurement of height and weight, a self-administered questionnaire collected information concerning occupation and work pattern, lifestyle behaviour, sleep, and the occurrence of an injury at work requiring treatment from a doctor during the past 12 months. Among paid employees providing information on work pattern, 3119 (21.2%) reported doing shift work (rotating with nights, rotating without nights, or permanent nights) and 1282 (8.7%) sustained a work injury. In unadjusted analysis, work injury was most strongly associated with employment in heavy manual occupations (3.6, 2.8 to 4.6) (relative risk, 95% CI), being male (1.9, 1.7 to 2.2), being obese (1.7, 1.5 to 2.0), working rotating shifts with nights (2.1, 1.7 to 2.5), and working more than three nights a week (1.9, 1.6 to 2.3). Snoring, apnoea or choking during sleep, sleep complaints, and excessive daytime sleepiness were also significantly associated with work injury. When mutually adjusting for all significant risk factors, rotating shift work, with or without nights, remained significantly associated with work injury (1.9, 1.5 to 2.4) and (1.8, 1.2 to 2.6), respectively. Working permanent night shifts was no longer significantly associated with work injury in the adjusted model. Work injury is highly associated with rotating shift work, even when accounting for increased exposure to high risk occupations, lifestyle factors, and excessive daytime sleepiness.

The effects of armodafinil on objective sleepiness and performance in a shift work disorder sample unselected for objective sleepiness.

PubMed

Howard, Ryan; Roth, Thomas; Drake, Christopher L

2014-06-01

Armodafinil is a medication used to treat excessive sleepiness in individuals with shift work disorder (SWD). In the present study, we investigate whether armodafinil can normalize nocturnal sleepiness in a group of typical SWD patients. Participants were 12 night workers (aged 33.8 ± 8.57 years, 7 female subjects) with excessive sleepiness (≥10 on the Epworth Sleepiness Scale; mean, 14.8 ± 3.16), meeting the International Classification of Sleep Disorders, Second Edition criteria for SWD, with no other sleep or medical disorders verified by polysomnogram. The multiple sleep latency test (MSLT) was not used as an entry criteria. Armodafinil was administered at 10:30 pm in a randomized, double-blind, placebo-controlled, crossover design with experimental nights separated by 1 week. Primary end point was the MSLT, with naps at 1:30, 3:30, 5:30, and 7:30 am. Other study measures included a sleepiness-alertness visual analog scale administered before each nap, and 2 computer-based performance tests evaluating attention and memory. Subjects with SWD had a mean MSLT of 5.3 ± 3.25 minutes, indicating a mean level of pathological sleepiness. Armodafinil significantly improved MSLT score to 11.1 ± 4.79 minutes (P = 0.006). Subjective levels of alertness on the visual analog scale also improved (P = 0.008). For performance, reaction time to central (P = 0.006) and peripheral (P = 0.003) stimuli and free recall memory (P = 0.05) were also improved. Armodafinil 150 mg administered at the beginning of a night shift normalizes nocturnal sleepiness in individuals with SWD unselected for objective sleepiness. Subjective measures of sleepiness and cognitive performance are also improved. This suggests that armodafinil can improve levels of nocturnal alertness to within normal daytime levels in the majority of patients with SWD.

Physiological and Psychological Aspects of Night and Shift Work.

ERIC Educational Resources Information Center

Wojtczak-Jaroszowa, Jadwiga

Results of physiological and psychological studies related to night and shift work are reviewed from the standpoint of their possible use by industry in understanding the problems of shift work and finding solutions. (New research data that has appeared since original preparation of the manuscript is presented in a three-part addendum with…

Shift and night work and long working hours--a systematic review of safety implications.

PubMed

Wagstaff, Anthony Sverre; Sigstad Lie, Jenny-Anne

2011-05-01

In order to devise effective preventive strategies, it is important to study workplace stressors that might increase the risk of workplace accidents - both affecting workers themselves as well as causing harm to third-parties. The aim of this report is to provide a systematic, updated overview and scientific review of empirical research regarding accidents in relation to long work hours and shift work, primarily based on epidemiological studies. The search for articles was part of a large review study on the effects of work hours on various health outcomes, safety, and performance. The search strategy included 5 international scientific databases, and nearly 7000 articles were initially identified using our search string. Following the application of inclusion and exclusion criteria, 443 publications were found and evaluated using a pre-defined scoring system. Of these, 43 concerned safety and accidents but only 14 were considered to be of high quality (total score 2 or 3 on a scale from 0-3) and therefore used for this study. Both shift work and long working hours present a substantial and well-documented detrimental effect on safety - all the studies that are included in this review have one or more significant findings in this respect. The trends are quite coherent although the increases in accident rates are mostly from 50% to 100%. In epidemiological terms, this may be seen as rather small differences. The use of such data is therefore only of importance if the accident incidence is high or if accidents may have large effects. The findings are most relevant to safety-critical activities such as the transport and health sectors. Work periods >8 hours carry an increased risk of accidents that cumulates, so that the increased risk of accidents at around 12 hours is twice the risk at 8 hours. Shift work including nights carries a substantial increased risk of accidents, whereas "pure" night work may bring some protection against this effect due to resynchronization. The evaluated studies give no clear indications of any age or gender being specifically susceptible or protected against the effects of work times scheduling on accident risk.