Modelling of human exposure to air pollution in the urban environment: a GPS-based approach.

PubMed

Dias, Daniela; Tchepel, Oxana

2014-03-01

The main objective of this work was the development of a new modelling tool for quantification of human exposure to traffic-related air pollution within distinct microenvironments by using a novel approach for trajectory analysis of the individuals. For this purpose, mobile phones with Global Positioning System technology have been used to collect daily trajectories of the individuals with higher temporal resolution and a trajectory data mining, and geo-spatial analysis algorithm was developed and implemented within a Geographical Information System to obtain time-activity patterns. These data were combined with air pollutant concentrations estimated for several microenvironments. In addition to outdoor, pollutant concentrations in distinct indoor microenvironments are characterised using a probabilistic approach. An example of the application for PM2.5 is presented and discussed. The results obtained for daily average individual exposure correspond to a mean value of 10.6 and 6.0-16.4 μg m(-3) in terms of 5th-95th percentiles. Analysis of the results shows that the use of point air quality measurements for exposure assessment will not explain the intra- and inter-variability of individuals' exposure levels. The methodology developed and implemented in this work provides time-sequence of the exposure events thus making possible association of the exposure with the individual activities and delivers main statistics on individual's air pollution exposure with high spatio-temporal resolution.

Validation of smoking-related virtual environments for cue exposure therapy.

PubMed

García-Rodríguez, Olaya; Pericot-Valverde, Irene; Gutiérrez-Maldonado, José; Ferrer-García, Marta; Secades-Villa, Roberto

2012-06-01

Craving is considered one of the main factors responsible for relapse after smoking cessation. Cue exposure therapy (CET) consists of controlled and repeated exposure to drug-related stimuli in order to extinguish associated responses. The main objective of this study was to assess the validity of 7 virtual reality environments for producing craving in smokers that can be used within the CET paradigm. Forty-six smokers and 44 never-smokers were exposed to 7 complex virtual environments with smoking-related cues that reproduce typical situations in which people smoke, and to a neutral virtual environment without smoking cues. Self-reported subjective craving and psychophysiological measures were recorded during the exposure. All virtual environments with smoking-related cues were able to generate subjective craving in smokers, while no increase was observed for the neutral environment. The most sensitive psychophysiological variable to craving increases was heart rate. The findings provide evidence of the utility of virtual reality for simulating real situations capable of eliciting craving. We also discuss how CET for smoking cessation can be improved through these virtual tools. Copyright © 2012 Elsevier Ltd. All rights reserved.

Determinants of personal exposure to PM2.5, ultrafine particle counts, and CO in a transport microenvironment.

PubMed

Kaur, S; Nieuwenhuijsen, M J

2009-07-01

Short-term human exposure concentrations to PM2.5, ultrafine particle counts (particle range: 0.02-1 microm), and carbon monoxide (CO) were investigated at and around a street canyon intersection in Central London, UK. During a four week field campaign, groups of four volunteers collected samples at three timings (morning, lunch, and afternoon), along two different routes (a heavily trafficked route and a backstreet route) via five modes of transport (walking, cycling, bus, car, and taxi). This was followed by an investigation into the determinants of exposure using a regression technique which incorporated the site-specific traffic counts, meteorological variables (wind speed and temperature) and the mode of transport used. The analyses explained 9, 62, and 43% of the variability observed in the exposure concentrations to PM2.5, ultrafine particle counts, and CO in this study, respectively. The mode of transport was a statistically significant determinant of personal exposure to PM2.5, ultrafine particle counts, and CO, and for PM2.5 and ultrafine particle counts it was the most important determinant. Traffic count explained little of the variability in the PM2.5 concentrations, but it had a greater influence on ultrafine particle count and CO concentrations. The analyses showed that temperature had a statistically significant impact on ultrafine particle count and CO concentrations. Wind speed also had a statistically significant effect but smaller. The small proportion in variability explained in PM2.5 by the model compared to the largest proportion in ultrafine particle counts and CO may be due to the effect of long-range transboundary sources, whereas for ultrafine particle counts and CO, local traffic is the main source.

Examination of the relationships between environmental exposures to volatile organic compounds and biochemical liver tests: application of canonical correlation analysis

PubMed Central

Liu, Jing; Drane, Wanzer; Liu, Xuefeng; Wu, Tiejian

2009-01-01

This study was to explore the relationships between personal exposure to ten volatile organic compounds (VOCs) and biochemical liver tests with the application of canonical correlation analysis. Data from a subsample of the 1999–2000 National Health and Nutrition Examination Survey were used. Serum albumin, total bilirubin (TB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and γ-glutamyl transferase (GGT) served as the outcome variables. Personal exposures to benzene, chloroform, ethylbenzene, tetrachloroethene, toluene, trichloroethene, o-xylene, m-, p-xylene, 1,4-dichlorobenzene, and methyl tert-butyl ether (MTBE) were assessed through the use of passive exposure monitors worn by study participants. The first two canonical correlations were 0.3218 and 0.2575, suggesting a positive correlation mainly between the six VOCs (benzene, ethylbenzene, toluene, o-xylene, m-, p-xylene, and MTBE) and the three biochemical liver tests (albumin, ALP, and GGT) and a positive correlation mainly between the two VOCs (1,4-dichlorobenzene and tetrachloroethene) and the two biochemical liver tests (LDH and TB). Subsequent multiple linear regressions show that exposure to benzene, toluene, or MTBE was associated with serum albumin, while exposure to tetrachloroethene was associated with LDH and total bilirubin. In conclusion, exposure to certain VOCs as a group or individually may influence certain biochemical liver test results in the general population. PMID:19117555

Examination of the relationships between environmental exposures to volatile organic compounds and biochemical liver tests: application of canonical correlation analysis.

PubMed

Liu, Jing; Drane, Wanzer; Liu, Xuefeng; Wu, Tiejian

2009-02-01

This study was to explore the relationships between personal exposure to 10 volatile organic compounds (VOCs) and biochemical liver tests with the application of canonical correlation analysis. Data from a subsample of the 1999-2000 National Health and Nutrition Examination Survey were used. Serum albumin, total bilirubin (TB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and gamma-glutamyl transferase (GGT) served as the outcome variables. Personal exposures to benzene, chloroform, ethylbenzene, tetrachloroethene, toluene, trichloroethene, o-xylene, m-,p-xylene, 1,4-dichlorobenzene, and methyl tert-butyl ether (MTBE) were assessed through the use of passive exposure monitors worn by study participants. The first two canonical correlations were 0.3218 and 0.2575, suggesting a positive correlation mainly between the six VOCs (benzene, ethylbenzene, toluene, o-xylene, m-,p-xylene, and MTBE) and the three biochemical liver tests (albumin, ALP, and GGT) and a positive correlation mainly between the two VOCs (1,4-dichlorobenzene and tetrachloroethene) and the two biochemical liver tests (LDH and TB). Subsequent multiple linear regressions show that exposure to benzene, toluene, or MTBE was associated with serum albumin, while exposure to tetrachloroethene was associated with LDH and total bilirubin. In conclusion, exposure to certain VOCs as a group or individually may influence certain biochemical liver test results in the general population.

Seasonality and the Response of the Thecosome Pteropod Limacina retroversa to CO2 in the Gulf of Maine

NASA Astrophysics Data System (ADS)

Maas, A.; Tarrant, A. M.; Bergan, A. J.; Wang, A. Z.; Lawson, G. L.

2016-02-01

Limacina retroversa is a thecosomatous pteropod found year round in the Gulf of Maine. Because carbonate chemistry within this shelf system is spatially variable and exhibits seasonal cycles, pteropods in this region may already be exposed to under-saturated, and hence corrosive, waters during certain seasons. To understand the implications of this variability, we have explored the physiological responses of L. retroversa at four time points over the course of a year to determine whether pteropods vary seasonally in their sensitivity to CO2 exposure on time-scales relevant to acclimation responses. In the laboratory, these animals were exposed to CO2 (ambient, 800, 1200 ppm) for 7-14 days and their response was assessed using an integrated set of metabolic, gene-expression and shell condition metrics. Similar to previous work with this species and others, pronounced changes in shell condition of exposed adults were discernible after less than 3 days of exposure, while changes to respiration rate were not consistently apparent. There were, however, seasonal variations in respiration rate indicative of an acclimation response. Differential expression analyses (RNAseq) revealed pronounced changes in gene expression among seasons, while laboratory CO2 exposure resulted in a lower number of differentially expressed transcripts. These gene expression studies, together with both respiration rate and shell condition metrics provide an integrated picture of the seasonal effect of CO2 on this sentinel species.

Glycemic control of diabetes patients under continuous rocket attacks.

PubMed

Soskolne, Varda; Dekel, Rachel; Vinker, Shlomo

2016-01-01

Evidence regarding the detrimental effects of exposure to stress on glycemic control among diabetes patients has mainly focused on personal life events or acute trauma. However, the effects of continuous exposure to extreme stress on type 2 diabetes patients have rarely been studied. The aim of the current study was to examine the association of continuous exposure to rocket attacks with glycemic control and with risk factors for diabetes complications among civilian type 2 diabetes patients. We focus on patients residing in the Western Negev in the south of Israel that has been subjected to rocket attacks fired from Gaza since the end of 2001. A two-arm retrospective cohort study of type 2 diabetes patients, aged 35-70 years, residing in a region with chronic exposure to rocket attacks (N = 1697) and in a non-exposed comparison region in Israel (N = 3000). Data were retrieved from the Health Maintenance Organization (HMO)'s database for four time periods representing exposure: chronic-2008; elevated-2009 (post'Cast Lead' operation); return to chronic-2010, 2011. Data included socio-demographic variables, HbA 1c , BMI, LDL cholesterol, blood pressure. General Linear Models (GLM) were used for analysis. For HbA 1c , the model yielded a significant main effect for time, a borderline significance main effect for region, and a significant time by region interaction: no differences in HbA 1c levels between the regions in 2008 and 2009, followed by significant differences between the regions in 2010 and 2011 when HbA 1c continued to increase in the exposed region but decreased in the comparison region. Regarding risk factors, a significant main effect for time for LDL cholesterol only, and significant main effects for region were found in all factors: BMI and LDL cholesterol were higher in the exposed than in the comparison region, but blood pressure values were lower. Continuous exposure to rocket attacks is associated with glycemic control and risk factors in a complex pattern. These preliminary findings require further studies of diverse types of civilian exposure to continuous extreme stress.

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.

Morphology and composition of beach-cast Posidonia oceanica litter on beaches with different exposures

NASA Astrophysics Data System (ADS)

Simeone, Simone; De Falco, Giovanni

2012-05-01

Posidonia oceanica seagrass litter is commonly found along sandy shores in the Mediterranean region, forming structures called banquettes, which are often removed in order to allow the beach to be used for tourism. This paper evaluates the relationship between the morphology and composition of banquettes and beach exposure to dominant waves. A Real Time Kinematic Differential Global Positioning System was used to evaluate the variability of banquettes and beach morphology over a period of 1 year. Banquette samples, collected at two different levels of the beach profile (i.e. foreshore and backshore), were used to evaluate the contribution of leaves, rhizomes and sediments to the total weight. Banquettes showed a higher volume, thickness and cross-shore length on exposed beaches, whereas narrower litter deposits were found on the sheltered beach. On exposed beaches, banquettes were deposited in beach zones characterized by changes in elevation. These changes in elevation were mainly due to the deposition and erosion of sediments and secondly to the deposition and or erosion of leaf litter. On sheltered beaches, the variability in beach morphology was low and was restricted to areas where the banquettes were located. The leaf/sediment ratio changed along the cross-shore profile. On the backshore, banquettes were a mixture of sediments and leaves, whereas leaves were the main component on the foreshore, independently of the beach exposure. The processes which control the morphodynamics in the swash zone could explain the variability of banquette composition along the cross-shore profile. Finally, this study highlighted that Posidonia oceanica seagrass litter plays an important role in the geomorphology of the beachface and its removal can have a harmful impact on the beaches.

Survival analysis with error-prone time-varying covariates: a risk set calibration approach

PubMed Central

Liao, Xiaomei; Zucker, David M.; Li, Yi; Spiegelman, Donna

2010-01-01

Summary Occupational, environmental, and nutritional epidemiologists are often interested in estimating the prospective effect of time-varying exposure variables such as cumulative exposure or cumulative updated average exposure, in relation to chronic disease endpoints such as cancer incidence and mortality. From exposure validation studies, it is apparent that many of the variables of interest are measured with moderate to substantial error. Although the ordinary regression calibration approach is approximately valid and efficient for measurement error correction of relative risk estimates from the Cox model with time-independent point exposures when the disease is rare, it is not adaptable for use with time-varying exposures. By re-calibrating the measurement error model within each risk set, a risk set regression calibration method is proposed for this setting. An algorithm for a bias-corrected point estimate of the relative risk using an RRC approach is presented, followed by the derivation of an estimate of its variance, resulting in a sandwich estimator. Emphasis is on methods applicable to the main study/external validation study design, which arises in important applications. Simulation studies under several assumptions about the error model were carried out, which demonstrated the validity and efficiency of the method in finite samples. The method was applied to a study of diet and cancer from Harvard’s Health Professionals Follow-up Study (HPFS). PMID:20486928

Factors affecting variability in the urinary biomarker 1,6-hexamethylene diamine in workers exposed to 1,6-hexamethylene diisocyanate.

PubMed

Gaines, Linda G T; Fent, Kenneth W; Flack, Sheila L; Thomasen, Jennifer M; Whittaker, Stephen G; Nylander-French, Leena A

2011-01-01

Although urinary 1,6-hexamethylene diamine (HDA) is a useful biomarker of exposure to 1,6-hexamethylene diisocyanate (HDI), a large degree of unexplained intra- and inter-individual variability exists between estimated HDI exposure and urine HDA levels. We investigated the effect of individual and workplace factors on urine HDA levels using quantitative dermal and inhalation exposure data derived from a survey of automotive spray painters exposed to HDI. Painters' dermal and breathing-zone HDI-exposures were monitored over an entire workday for up to three separate workdays, spaced approximately one month apart. One urine sample was collected before the start of work with HDI-containing paints, and multiple samples were collected throughout the workday. Using mixed effects multiple linear regression modeling, coverall use resulted in significantly lower HDA levels (p = 0.12), and weekday contributed to significant variability in HDA levels (p = 0.056). We also investigated differences in urine HDA levels stratified by dichotomous and classification covariates using analysis of variance. Use of coveralls (p = 0.05), respirator type worn (p = 0.06), smoker status (p = 0.12), paint-booth type (p = 0.02), and more than one painter at the shop (p = 0.10) were all found to significantly affect urine HDA levels adjusted for creatinine concentration. Coverall use remained significant (p = 0.10), even after adjusting for respirator type. These results indicate that the variation in urine HDA level is mainly due to workplace factors and that appropriate dermal and inhalation protection is required to prevent HDI exposure.

Vehicle occupant exposure to carbon monoxide.

PubMed

Koushki, P A; al-Dhowalia, K H; Niaizi, S A

1992-12-01

This paper focuses on the auto commuting micro-environment and presents typical carbon monoxide (CO) concentrations to which auto commuters in central Riyadh, Saudi Arabia were exposed. Two test vehicles traveling over four main arterial roadways were monitored for inside and outside CO levels during eighty peak and off-peak hours extending over an eight-month period. The relative importance of several variables which explained the variability in CO concentrations inside autos was also assessed. It was found that during peak hours auto commuters were exposed to mean CO levels that ranged from 30 to 40 ppm over trips that typically took between 25 to 40 minutes. The mean ratio of inside to outside CO levels was 0.84. Results of variance component analyses indicated that the most important variables affecting CO concentrations inside autos were, in addition to the smoking of vehicle occupants, traffic volume, vehicle speed, period of day and wind velocity. An increase in traffic volume from 1,000 to 5,000 vehicles per hour (vph) increased mean CO level exposure by 71 percent. An increase in vehicle speed from 14 to 55 km/h reduced mean CO exposure by 36 percent. The number of traffic interruptions had a moderate effect on mean concentrations of CO inside vehicles.

Water-contact patterns in relation to Schistosoma haematobium infection

PubMed Central

Dalton, P. R.; Pole, D.

1978-01-01

Water-contact observations were carried out on a population exposed to Schistosoma haematobium in a village situated on a man-made lake, Lake Volta, Ghana. The observations were made over a period of 12 months prior to the introduction of control measures. A multiple regression analysis was performed on the results of observations on 132 individuals, with egg output as the dependent variable and various types of water-contact activity, as well as age and sex, as independent variables. In the analysis, specific activities, notably water-contact for domestic purposes and activities associated with fishermen's canoes, were found to be significantly related to schistosomiasis. Age was less important than degree of exposure as a contributory factor to variations in infection rates: the reduced intensity of infection of S. haematobium in the older age groups could be mainly due to a lower level of exposure to the cercarial population. PMID:308406

Multiple exposure routes of a pesticide exacerbate effects on a grazing mayfly.

PubMed

Pristed, Mathias Joachim Skov; Bundschuh, Mirco; Rasmussen, Jes Jessen

2016-09-01

Hydrophobic pesticides such as pyrethroid insecticides tend to occur in their soluble form mainly as transient pulses in streams. In addition, they are regularly detected in significant quantities adsorbed to stream sediments and other organic in-stream structures. Consequently, stream biota is likely subjected to pesticide exposure via multiple routes. In this study we aimed at investigating the influence of exposure routes for the pyrethroid insecticide lambda-cyhalothrin on the grazing mayfly Heptagenia sulphurea. Therefore, H. sulphurea was exposed to lambda-cyhalothrin via single- (water or biofilm) or biphasic exposure (water and biofilm) at environmentally realistic concentrations (0, 0.1, 1μgL(-1)) and exposure duration (2h) in a full factorial design (n=5). Mortality, moulting frequency, and biofilm accrual (proxy for feeding rate) were recorded subsequent to a 7 d post exposure period. Mortality significantly increased and moulting frequency significantly decreased with increasing concentrations of lambda-cyhalothrin in the water phase whereas exposure via biofilm prompted no significant effects on these endpoints (α=0.05). Effect predictions systematically underestimated and overestimated effects for mortality and moulting frequency, respectively. Similarly, mayfly feeding rate was significantly reduced by water phase exposure whereas pre-exposed biofilm did not significantly affect this variable. However, we found a significant but non-systematic interaction between water phase and biofilm exposure on mayfly feeding rate. Our results show that exposure to the same pesticide via multiple exposure routes may increase the magnitude of effects beyond the level predicted from single phase exposures which has clear implications for the aquatic risk assessment of hydrophobic pesticides. However, our results additionally reveal that interactions between pesticide exposure routes may vary between selected dependent variables. We emphasize that unravelling the underlying mechanisms causing these discrepancies in interactive effects between exposure routes is a major aspect that should receive further attention in future research. Copyright © 2016 Elsevier B.V. All rights reserved.

Adversity in Preschool-Aged Children: Effects on Salivary Interleukin-1β

PubMed Central

Tyrka, Audrey R.; Parade, Stephanie H.; Valentine, Thomas R.; Eslinger, Nicole M.; Seifer, Ronald

2016-01-01

Exposure to early life adversity is linked to impaired affective, cognitive, and behavioral functioning and increases risk for various psychiatric and medical conditions. Stress-induced increases in pro-inflammatory cytokines may be a biological mechanism of these effects. Few studies have examined cytokine levels in children experiencing early life adversity, and very little research has investigated cytokines or other markers of inflammation in saliva. In the present study, we examined salivary IL-1β and C-reactive protein (CRP) levels in relation to stress exposure in 40 children aged 3 to 5 years who were enrolled in a larger study of early life adversity. Childhood maltreatment status was assessed via review of child welfare records, and contextual stress exposure, traumatic life event history, and symptoms of psychopathology were assessed via caregiver interviews at a home visit. In a subsequent visit, salivary IL-1β and CRP were obtained before and after participation in four emotion-eliciting tasks. Number of past month contextual stressors, lifetime contextual stressors, and traumatic life events each demonstrated a significant main effect on IL-1β. Baseline IL-1β was positively associated with each of the significant main-effect adversities. Post-challenge IL-1β displayed positive associations with each adversity variable, but were not significant. CRP was not significantly associated with any of the adversity variables. Given evidence suggesting involvement of IL-1β in the neuropathology of psychiatric conditions, these results may have important implications for developmental outcomes. PMID:25997772

The Effect of Work Characteristics on Dermatologic Symptoms in Hairdressers

PubMed Central

2014-01-01

Objectives Hairdressers in Korea perform various tasks and are exposed to health risk factors such as chemical substances or prolonged duration of wet work. The objective of this study is to provide descriptive statistics on the demographics and work characteristics of hairdressers in Korea and to identify work-related risk factors for dermatologic symptoms in hairdressers. Methods 1,054 hairdressers were selected and analyzed for this study. Independent variables were exposure to chemical substances, the training status of the hairdressers, and the main tasks required of them, and the dependent variable was the incidence of dermatologic symptoms. The relationships between work characteristics and dermatologic symptoms were evaluated by estimating odds ratios using multiple logistic regression analysis. Results Among the 1,054 study subjects, 212 hairdressers (20.1%) complained of dermatologic symptoms, and the symptoms were more prevalent in younger, unmarried or highly educated hairdressers. The main tasks that comprise the majority of the wet work were strictly determined by training status, since 96.5% of staff hairdressers identified washing as their main task, while only 1.5% and 2.0% of master and designer hairdressers, respectively, identified this as their main task. Multiple logistic regressions was performed to estimate odds ratios. While exposure to hairdressing chemicals showed no significant effect on the odds ratio for the incidence of dermatologic symptoms, higher odds ratios of dermatologic symptoms were shown in staff hairdressers (2.70, 95% CI: 1.32 - 5.51) and in hairdressers who perform washing as their main task (2.03, 95% CI: 1.22 - 3.37), after adjusting for general and work characteristics. Conclusions This study showed that the training status and main tasks of hairdressers are closely related to each other and that the training status and main tasks of hairdressers are related to the incidence of dermatologic symptoms. This suggests that in the future, regulations on working conditions and health management guidelines for hairdressers should be established. PMID:25028609

Exposure to respirable dust and manganese and prevalence of airways symptoms, among Swedish mild steel welders in the manufacturing industry.

PubMed

Hedmer, Maria; Karlsson, Jan-Eric; Andersson, Ulla; Jacobsson, Helene; Nielsen, Jörn; Tinnerberg, Håkan

2014-08-01

Welding fume consists of metal fumes, e.g., manganese (Mn) and gases, e.g., ozone. Particles in the respirable dust (RD) size range dominate. Exposure to welding fume could cause short- and long-term respiratory effects. The prevalence of work-related symptoms among mild steel welders was studied, and the occupational exposure to welding fumes was quantified by repeated measurements of RD, respirable Mn, and ozone. Also the variance components were studied. A questionnaire concerning airway symptoms and occupational history was answered by 79% of a cohort of 484 welders. A group of welders (N = 108) were selected and surveyed by personal exposure measurements of RD and ozone three times during 1 year. The welders had a high frequency of work-related symptoms, e.g., stuffy nose (33%), ocular symptoms (28%), and dry cough (24%). The geometric mean exposure to RD and respirable Mn was 1.3 mg/m(3) (min-max 0.1-38.3 mg/m(3)) and 0.08 mg/m(3) (min-max <0.01-2.13 mg/m(3)), respectively. More than 50% of the Mn concentrations exceeded the Swedish occupational exposure limit (OEL). Mainly, low concentrations of ozone were measured, but 2% of the samples exceeded the OEL. Of the total variance for RD, 30 and 33% can be attributed to within-worker variability and between-company variability, respectively. Welders had a high prevalence of work-related symptom from the airways and eyes. The welders' exposure to Mn was unacceptably high. To reduce the exposure further, control measures in the welding workshops are needed. Correct use of general mechanical ventilation and local exhaust ventilation can, for example, efficiently reduce the exposure.

Different sensitization to storage mites depending on the co-exposure to house dust mites.

PubMed

Morales, María; Iraola, Victor; Leonor, José Ramón; Bartra, Joan; Rodríguez, Fernando; Boquete, Manuel; Huertas, Ángel Julio; Paniagua, María Josefa; Pinto, Helder; Carnés, Jerónimo

2015-01-01

Co-sensitization to house dust mites (HDMs) and storage mites (SMs) is very frequent, although the clinical relevance is not well established. To describe the pattern of sensitization and immunologic characterization of patients with positive skin prick test reactions to HDMs and SMs in 4 areas of Spain, selected according to high exposure to HDMs and variable exposure to SMs. One hundred sixty-nine individuals with positive skin prick test reactions to HDMs and SMs were included. Specific IgE levels to different mite species and to Der p 1, Der p 2, and Der p 10 were determined. Immunoblots to Dermatophagoides pteronyssinus, Lepidoglyphus destructor, and Tyrophagus putrescentiae extracts were carried out, and allergograms were obtained. Results of different areas were compared. A high rate of polysensitization to SMs was observed, although 12% of participants did not have specific IgE to any SM species. Sensitization to Dermatophagoides species, Der p 2, and L destructor were predominant, although significant differences were observed among areas depending on the grade of exposure to SMs. In areas with high exposure, the SM allergogram showed greater recognition of group 2 allergen. Sensitization patterns to SMs in patients sensitized to HDMs and SMs differ depending on the exposure to SMs. Sensitization, mainly to L destructor, seems to exist in areas with high exposure, possibly with group 2 allergens mainly involved. However, in areas with low SM populations, sensitizations observed by skin prick testing appear to be related to HDM exposure. Copyright © 2015 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Effectiveness of Cognitive Processing Therapy and Prolonged Exposure in the Department of Veterans Affairs.

PubMed

Rutt, Benjamin T; Oehlert, Mary E; Krieshok, Thomas S; Lichtenberg, James W

2018-04-01

Objective This study evaluated the effectiveness of cognitive processing therapy and prolonged exposure in conditions reflective of current clinical practice within the Veterans Health Administration. Method This study involved a retrospective review of 2030 charts. A total of 750 veterans from 10 U.S. states who received cognitive processing therapy or prolonged exposure in individual psychotherapy were included in the study (participants in cognitive processing therapy, N = 376; participants in prolonged exposure, N = 374). The main dependent variable was self-reported posttraumatic stress disorder symptoms as measured by total scores on the Posttraumatic Stress Disorder Checklist. The study used multilevel modeling to evaluate the absolute and relative effectiveness of both treatments and determine the relationship between patient-level variables and total Posttraumatic Stress Disorder Checklist scores during treatment. Results Cognitive processing therapy and prolonged exposure were equally effective at reducing total Posttraumatic Stress Disorder Checklist scores. Veterans who completed therapy reported significantly larger reductions in the Posttraumatic Stress Disorder Checklist than patients who did not complete therapy. There were no significant differences in the improvement of posttraumatic stress disorder symptoms with respect to age and three racial/ethnic groups (Caucasian, African American, and Hispanic). Conclusions Cognitive processing therapy and prolonged exposure were shown to be effective in conditions highly reflective of clinical practice and with a highly diverse sample of veterans. Challenges related to dropout from trauma focused therapy should continue to be researched.

The street as an area of human exposure in an earthquake aftermath: the case of Lorca, Spain, 2011

NASA Astrophysics Data System (ADS)

Bertran Rojo, Marc; Beck, Elise; Lutoff, Céline

2017-04-01

The earthquake which struck the city of Lorca, Spain, on 11 May 2011 killed 9 people, injured over 300 and caused considerable damage, including one collapsed building. Streets near buildings were the main danger areas for people. This article proposes an dynamic ad hoc spatio-temporal method for studying individual evacuation after an earthquake. Its application to the Lorca case shows the spatial and temporal variability of individual exposure levels in the street during the hours following the shock. As yet little studied, human exposure deserves more attention, particularly in zones of moderate seismicity like the Euro-Mediterranean area. The results of this study could be helpful for enhancing the evacuation planning after an earthquake, stressing the specific dangers in the street.

Methyl mercury exposure and neurodevelopmental outcomes in the Seychelles Child Development Study Main cohort at age 22 and 24years.

PubMed

van Wijngaarden, Edwin; Thurston, Sally W; Myers, Gary J; Harrington, Donald; Cory-Slechta, Deborah A; Strain, J J; Watson, Gene E; Zareba, Grazyna; Love, Tanzy; Henderson, Juliette; Shamlaye, Conrad F; Davidson, Philip W

All fish contain methyl mercury (MeHg), a known neurotoxicant at adequate dosage. There is still substantial scientific uncertainty about the consequences, if any, of mothers consuming fish with naturally-acquired levels of MeHg contamination. In 1989-1990, we recruited the Main Cohort of the Seychelles Child Development Study to assess the potential developmental effects of prenatal MeHg exposure. We report here on associations with neurodevelopmental outcomes obtained at 22 and 24years of age. Neurodevelopmental tests at 22years included the Boston Naming Test, Cambridge Neuropsychological Test Automated Battery (CANTAB), and the Profile of Mood States. At 24years, we administered the Stroop Word-Color Test, the Barkley Adult ADHD Rating Scale, the Test of Variables of Attention, and the Finger Tapping test. We also administered a healthy behaviors survey at both ages. Primary analyses examined covariate-adjusted associations in multiple linear regression models with prenatal MeHg exposure. In secondary analyses we also examined associations with recent postnatal MeHg exposure. We did not observe adverse associations between prenatal MeHg exposure and any of the measured endpoints. Some measures of attention, executive function, and delayed recall showed improved performance with increasing exposure. Secondary analysis did not show consistent patterns of association with postnatal exposure. Our cohort has been examined at ten different ages over 24years of follow-up. Findings suggest that prenatal and recent postnatal MeHg exposure from ocean fish consumption is not adversely associated with neurobehavioral development at levels that are about ten times higher than typical U.S. exposures. Copyright © 2016 Elsevier Inc. All rights reserved.

Residential exposure to radiofrequency fields from mobile phone base stations, and broadcast transmitters: a population-based survey with personal meter.

PubMed

Viel, J F; Clerc, S; Barrera, C; Rymzhanova, R; Moissonnier, M; Hours, M; Cardis, E

2009-08-01

Both the public perceptions, and most published epidemiologic studies, rely on the assumption that the distance of a particular residence from a base station or a broadcast transmitter is an appropriate surrogate for exposure to radiofrequency fields, although complex propagation characteristics affect the beams from antennas. The main goal of this study was to characterise the distribution of residential exposure from antennas using personal exposure meters. A total of 200 randomly selected people were enrolled. Each participant was supplied with a personal exposure meter for 24 h measurements, and kept a time-location-activity diary. Two exposure metrics for each radiofrequency were then calculated: the proportion of measurements above the detection limit (0.05 V/m), and the maximum electric field strength. Residential address was geocoded, and distance from each antenna was calculated. Much of the time, the recorded field strength was below the detection level (0.05 V/m), the FM band standing apart with a proportion above the detection threshold of 12.3%. The maximum electric field strength was always lower than 1.5 V/m. Exposure to GSM and DCS waves peaked around 280 m and 1000 m from the antennas. A downward trend was found within a 10 km range for FM. Conversely, UMTS, TV 3, and TV 4&5 signals did not vary with distance. Despite numerous limiting factors entailing a high variability in radiofrequency exposure assessment, but owing to a sound statistical technique, we found that exposures from GSM and DCS base stations increase with distance in the near source zone, to a maximum where the main beam intersects the ground. We believe these results will contribute to the ongoing public debate over the location of base stations and their associated emissions.

Noise and hand-arm vibration exposure in relation to the risk of hearing loss.

PubMed

Pettersson, Hans; Burström, Lage; Hagberg, Mats; Lundström, Ronnie; Nilsson, Tohr

2012-01-01

The aim of this study was to examine the possible association of combined exposure of noise and hand-arm vibration (HAV) and the risk of noise-induced hearing loss. Workers in a heavy engineering industry were part of a dynamic cohort. Of these workers, 189 had HAV exposure, and their age and hearing status were recorded in the same year and were, therefore, included in the analysis. Data on HAV duration and acceleration was gathered through questionnaires, observations, and measurements. All available audiograms were categorized into normal and hearing loss. The first exposure variable included the lifetime HAV exposure. The lifetime HAV exposure was multiplied by the acceleration of HAV for the second and third exposure variable. Logistic regression using the Generalized Estimation Equations method was chosen to analyze the data to account for the repeated measurements. The analysis was performed with both continuous exposure variables and with exposure variables grouped into exposure quartiles with hearing loss as an outcome and age as a covariate. With continuous exposure variables, the odds ratio (OR) with a 95% confidence interval (CI) for hearing loss was equal to or greater than one for all exposure variables. When the exposure variables were grouped into quartiles, the OR with a 95% CI was greater than one at the third and fourth quartile. The results show that working with vibrating machines in an environment with noise exposure increases the risk of hearing loss, supporting an association between exposure to noise and HAV, and the noise-induced hearing loss.

Parasite fitness traits under environmental variation: disentangling the roles of a chytrid's immediate host and external environment.

PubMed

Van den Wyngaert, Silke; Vanholsbeeck, Olivier; Spaak, Piet; Ibelings, Bas W

2014-10-01

Parasite environments are heterogeneous at different levels. The first level of variability is the host itself. The second level represents the external environment for the hosts, to which parasites may be exposed during part of their life cycle. Both levels are expected to affect parasite fitness traits. We disentangle the main and interaction effects of variation in the immediate host environment, here the diatom Asterionella formosa (variables host cell volume and host condition through herbicide pre-exposure) and variation in the external environment (variables host density and acute herbicide exposure) on three fitness traits (infection success, development time and reproductive output) of a chytrid parasite. Herbicide exposure only decreased infection success in a low host density environment. This result reinforces the hypothesis that chytrid zoospores use photosynthesis-dependent chemical cues to locate its host. At high host densities, chemotaxis becomes less relevant due to increasing chance contact rates between host and parasite, thereby following the mass-action principle in epidemiology. Theoretical support for this finding is provided by an agent-based simulation model. The immediate host environment (cell volume) substantially affected parasite reproductive output and also interacted with the external herbicide exposed environment. On the contrary, changes in the immediate host environment through herbicide pre-exposure did not increase infection success, though it had subtle effects on zoospore development time and reproductive output. This study shows that both immediate host and external environment as well as their interaction have significant effects on parasite fitness. Disentangling these effects improves our understanding of the processes underlying parasite spread and disease dynamics.

The effects of hot nights on mortality in Barcelona, Spain

NASA Astrophysics Data System (ADS)

Royé, D.

2017-12-01

Heat-related effects on mortality have been widely analyzed using maximum and minimum temperatures as exposure variables. Nevertheless, the main focus is usually on the former with the minimum temperature being limited in use as far as human health effects are concerned. Therefore, new thermal indices were used in this research to describe the duration of night hours with air temperatures higher than the 95% percentile of the minimum temperature (hot night hours) and intensity as the summation of these air temperatures in degrees (hot night degrees). An exposure-response relationship between mortality due to natural, respiratory, and cardiovascular causes and summer night temperatures was assessed using data from the Barcelona region between 2003 and 2013. The non-linear relationship between the exposure and response variables was modeled using a distributed lag non-linear model. The estimated associations for both exposure variables and mortality shows a relationship with high and medium values that persist significantly up to a lag of 1-2 days. In mortality due to natural causes, an increase of 1.1% per 10% (CI95% 0.6-1.5) for hot night hours and 5.8% per each 10° (CI95% 3.5-8.2%) for hot night degrees is observed. The effects of hot night hours reach their maximum with 100% and lead to an increase by 9.2% (CI95% 5.3-13.1%). The hourly description of night heat effects reduced to a single indicator in duration and intensity is a new approach and shows a different perspective and significant heat-related effects on human health.

Farm work exposure of older male farmers in Saskatchewan.

PubMed

Voaklander, Donald C; Dosman, James A; Hagel, Louise M; Warsh, Joel; Pickett, William

2010-07-01

The average age of farmers in North America is increasing each year. Research has determined that age and health status are both related to increased risk of injury. The purpose of this research was to determine the association of health and medication factors with exposure to farm work in older male farmers. As part of a cohort study to study determinants of injury on Saskatchewan farms, 5,502 farm people associated with 2,386 Saskatchewan farms were surveyed by mail questionnaire during the winter of 2007. The primary dependent variable was average hours per week of farm work. Independent variables included illnesses, age, and medication use. The mean number of hours worked per week by farmers aged 55 years and older was 48. There was a significant relationship between age and hours worked with each year of age accounting for about 0.85 hr less work per week. Medication use was related to a reduction in weekly work hours during the busy fall season but was not related to work exposure averaged over the whole year. In multivariable linear regression analysis, the main contributing variables to farm work exposure were: retired status (-), working off farm (-), and age (-). The amount of hours older farmers work on the farm is considerable compared to any other occupational category. While there is a declining trend in the amount of work, a 75-year-old farmer still works, on average, about 34 hr per week. Some farmers do appear to self-limit during busy times of the year if they are taking medication. 2010 Wiley-Liss, Inc.

Electromagnetic fields produced by GSM cellular phones and heart rate variability.

PubMed

Parazzini, Marta; Ravazzani, Paolo; Tognola, Gabriella; Thuróczy, György; Molnar, Ferenc B; Sacchettini, Alessio; Ardesi, Gianluca; Mainardi, Luca Tommaso

2007-02-01

In this study, 26 healthy young volunteers were submitted to 900 MHz (2 W) GSM cellular phone exposure and to sham exposure in separate sessions. The study was designed to assess cardiac regulatory mechanism in different autonomic nervous system (ANS) states during exposure to low-intensity EMF. Rest-to-stand protocol was applied to evaluate ANS in quiet condition (rest, vagal prevalence) and after a sympathetic activation (stand). The procedure is conducted twice in a double-blind design: once with a genuine EMF exposure and once with a sham exposure (at least 24 h apart). During each session three-leads electrocardiograms were recorded and RR series extracted off-line. Time domain and frequency domain HRV parameters were calculated in every phase of the protocol and during different exposures. The analysis of the data show there was no statistically significant effect due to EMF exposure both on main (i.e., RR mean) and most of the other HRV parameters. A weak interaction between some HRV parameters (i.e., SDNN, TINN, and triangular index in time domain and LF power in frequency domain analysis) and RF exposure was observed and this effect seems to be gathered around the sympathetic response to stand.

Flood Risk Vulnerability Assessment: What are the Main Factors? Hierarchization of The Main Factors at a Regional Scale

NASA Astrophysics Data System (ADS)

Jouannic, G.; Kolli, Z.; Legendre, T.; Marchetti, M.; Gastaud, P.; Gargani, J.; Lermet, R.; Augeard, C.; Felts, D.; Arki, F.

2015-12-01

Recent studies have shown that the national flood risk exposure is high in France, with one fourth of the total population and a third of jobs located in risk areas. In this context, a global vulnerability assessment methodology is currently being developed in France to bring adequate tools for local territories to manage flood risk. This study addresses the question of the quantification, the qualification and the choice of these vulnerability indicators for a given territory. This work aims to propose a classification of nearly 40 of these indicators in terms of their relative impacts on the risk level estimated on two territories: Chalon-sur-Saône (Saône river) Garonne estuary (Garonne and Dordogne rivers, and Atlantic ocean) Through these cases study, 3 different spatial scales have been compared: the Prés-Saint-Jean district inside Chalon (0.6 km²), the city of Ambès (28.8 km²) and Chalon with its suburbs (72.2 km²). A principal component analysis (PCA) was applied and indicated a threshold in terms of urban impacts between the different flood scenarios. On Chalon, the PCA discriminates 2 groups of flood and highlighted a threshold between T20 and T50. A partial least-square regression (PLS) was computed to make predictions on vulnerability indicators values modelled on new flood scenarios. Their results were is useful to identify the most relevant vulnerability indicators as a function of their flood exposure. These statistical analysis aims to highlight the relationship between a variable of exposure level (hydrologic impact: water levels and flow velocity) with spatialized vulnerability indicators in a 100 m grid (e.g., population, job, etc.). Finally, to get a hierarchy of variables depending on their impact on the risk level, an ANOVA was computed. The selection of variables was performed with a stepwise selection to assess contributions of each dependant variable on the F-statistic as they are added to or removed from the model.

[Cross-sectional study of the variability of work-related stress among post-graduate medical residents at the main University Polyclinic of Sicily].

PubMed

Costantino, Claudio; Albeggiani, Valentina; Bonfante, Maria Stefania; Monte, Caterina; Lo Cascio, Nunzio; Mazzucco, Walter

2015-02-10

Among health care workers (HCWs), work-related stress is one of the main topics in risk assessment and prevention at the workplace. Post-graduate medical residents (MRs) are a group of HCWs comparable to medical doctors in terms of occupational exposure and occurrence of work-related stress syndromes. Risk assessment of work-related stress among MRs attending the major University Hospital of Sicily. A cross-sectional survey via an anonymous and self-administered questionnaire. 45% of clinical MRs and 37% of surgical MRs had access to compensatory rest days against 92% of MRs of the services area (p<0.001). A work attendance recording system for MRs was available in 80% of the postgraduate medical schools of the services area, in 60% of the clinical postgraduate schools and in 50% of the surgical postgraduate schools (p<0.001). MRs of the postgraduate surgical schools reported having access to work breaks (41%) with less frequency compared to clinical (60%) and services MRs (74%) (p<0.001). Both clinical (47%) and surgical MRs (47%) were more exposed to work-related stress than MRs of the services area (27%) (p<0.001). The survey demonstrated excess exposure to work-related stress for all the considered variables in MRs of the surgical area, compared with MRs of clinical and services areas. It is strongly recommended to provide specific training programmes aimed at managing the MRs' risk of exposure to work-related stress, focusing both on the workers and the work environment.

Dextromethorphan as a phenotyping test to predict endoxifen exposure in patients on tamoxifen treatment.

PubMed

de Graan, Anne-Joy M; Teunissen, Sebastiaan F; de Vos, Filip Y F L; Loos, Walter J; van Schaik, Ron H N; de Jongh, Felix E; de Vos, Aad I; van Alphen, Robbert J; van der Holt, Bronno; Verweij, Jaap; Seynaeve, Caroline; Beijnen, Jos H; Mathijssen, Ron H J

2011-08-20

Tamoxifen, a widely used agent for the prevention and treatment of breast cancer, is mainly metabolized by CYP2D6 and CYP3A to form its most abundant active metabolite, endoxifen. Interpatient variability in toxicity and efficacy of tamoxifen is substantial. Contradictory results on the value of CYP2D6 genotyping to reduce the variable efficacy have been reported. In this pharmacokinetic study, we investigated the value of dextromethorphan, a known probe drug for both CYP2D6 and CYP3A enzymatic activity, as a potential phenotyping probe for tamoxifen pharmacokinetics. In this prospective study, 40 women using tamoxifen for invasive breast cancer received a single dose of dextromethorphan 2 hours after tamoxifen intake. Dextromethorphan, tamoxifen, and their respective metabolites were quantified. Exposure parameters of all compounds were estimated, log transformed, and subsequently correlated. A strong and highly significant correlation (r = -0.72; P < .001) was found between the exposures of dextromethorphan (0 to 6 hours) and endoxifen (0 to 24 hours). Also, the area under the plasma concentration-time curve of dextromethorphan (0 to 6 hours) and daily trough endoxifen concentration was strongly correlated (r = -0.70; P < .001). In a single patient using the potent CYP2D6 inhibitor paroxetine, the low endoxifen concentration was accurately predicted by dextromethorphan exposure. Dextromethorphan exposure after a single administration adequately predicted endoxifen exposure in individual patients with breast cancer taking tamoxifen. This test could contribute to the personalization and optimization of tamoxifen treatment, but it needs additional validation and simplification before being applicable in future dosing strategies.

Do environmental factors affect male fathead minnow (Pimephales promelas) response to estrone? Part 1. Dissolved oxygen and sodium chloride.

PubMed

Feifarek, D J; Shappell, N W; Schoenfuss, H L

2018-01-01

Laboratory exposures indicate that estrogens and their mimics can cause endocrine disruption in male fishes, yet while studies of resident fish populations in estrogen-polluted waters support these findings, biomarker expression associated with field versus laboratory exposure to estrogenic endocrine disruptors (EDs) often differ dramatically. Two of the environmental parameters often found to vary in dynamic aquatic ecosystems were chosen (dissolved oxygen [DO] and sodium chloride concentrations) to assess their potential impact on ED exposure. In separate experiments, male fathead minnows (Pimephales promelas) were exposed to estrone (E1) a natural ED, under either two concentrations of DO, or two concentrations of sodium chloride, in a laboratory flow-through system. Morphological and hematological parameters were assessed. While vitellogenin concentrations were elevated with exposure to estrone (29 to 390ng/L), the effect on other indices were variable. Estrone exposure altered SSC, blood glucose, hematocrit, and hepatic and gonado-somatic index in 1 of 4 experiments, while it decreased body condition factor in 3 of 4 experiments. At the concentrations tested, no main effect differences (P<0.05) were found associated with DO or sodium chloride treatments, except in one experiment low DO resulted in a decrease in secondary sex characteristic score (SSC). The combination of DO or sodium chloride and E1 altered blood glucose in one experiment each. These results indicate the variability of fathead minnow response to estrone, even within the confines of controlled laboratory conditions. Published by Elsevier B.V.

Systematically Extracting Metal- and Solvent-Related Occupational Information from Free-Text Responses to Lifetime Occupational History Questionnaires

PubMed Central

Friesen, Melissa C.; Locke, Sarah J.; Tornow, Carina; Chen, Yu-Cheng; Koh, Dong-Hee; Stewart, Patricia A.; Purdue, Mark; Colt, Joanne S.

2014-01-01

Objectives: Lifetime occupational history (OH) questionnaires often use open-ended questions to capture detailed information about study participants’ jobs. Exposure assessors use this information, along with responses to job- and industry-specific questionnaires, to assign exposure estimates on a job-by-job basis. An alternative approach is to use information from the OH responses and the job- and industry-specific questionnaires to develop programmable decision rules for assigning exposures. As a first step in this process, we developed a systematic approach to extract the free-text OH responses and convert them into standardized variables that represented exposure scenarios. Methods: Our study population comprised 2408 subjects, reporting 11991 jobs, from a case–control study of renal cell carcinoma. Each subject completed a lifetime OH questionnaire that included verbatim responses, for each job, to open-ended questions including job title, main tasks and activities (task), tools and equipment used (tools), and chemicals and materials handled (chemicals). Based on a review of the literature, we identified exposure scenarios (occupations, industries, tasks/tools/chemicals) expected to involve possible exposure to chlorinated solvents, trichloroethylene (TCE) in particular, lead, and cadmium. We then used a SAS macro to review the information reported by study participants to identify jobs associated with each exposure scenario; this was done using previously coded standardized occupation and industry classification codes, and a priori lists of associated key words and phrases related to possibly exposed tasks, tools, and chemicals. Exposure variables representing the occupation, industry, and task/tool/chemicals exposure scenarios were added to the work history records of the study respondents. Our identification of possibly TCE-exposed scenarios in the OH responses was compared to an expert’s independently assigned probability ratings to evaluate whether we missed identifying possibly exposed jobs. Results: Our process added exposure variables for 52 occupation groups, 43 industry groups, and 46 task/tool/chemical scenarios to the data set of OH responses. Across all four agents, we identified possibly exposed task/tool/chemical exposure scenarios in 44–51% of the jobs in possibly exposed occupations. Possibly exposed task/tool/chemical exposure scenarios were found in a nontrivial 9–14% of the jobs not in possibly exposed occupations, suggesting that our process identified important information that would not be captured using occupation alone. Our extraction process was sensitive: for jobs where our extraction of OH responses identified no exposure scenarios and for which the sole source of information was the OH responses, only 0.1% were assessed as possibly exposed to TCE by the expert. Conclusions: Our systematic extraction of OH information found useful information in the task/chemicals/tools responses that was relatively easy to extract and that was not available from the occupational or industry information. The extracted variables can be used as inputs in the development of decision rules, especially for jobs where no additional information, such as job- and industry-specific questionnaires, is available. PMID:24590110

Risk assessment from exposure to arsenic, antimony, and selenium in urban gardens (Madrid, Spain).

PubMed

De Miguel, Eduardo; Izquierdo, Miguel; Gómez, Amaia; Mingot, Juan; Barrio-Parra, Fernando

2017-02-01

The authors discuss the geochemical behavior of arsenic (As), antimony (Sb), and selenium (Se) in urban gardens and the human health implications associated with urban agriculture. A total of 42 samples from 7 urban gardens in Madrid, Spain, were collected from the top 20 cm of soil. Concentrations of As, Sb, and Se and the main soil properties (i.e., total iron, pH, texture, calcium carbonate, and organic matter) were determined. A significant correlation was found between As and Sb and calcium carbonate, indicating the possibility of surface adsorption or ligand exchange with the carbonate group. Also, Sb seemed to form stable chelates with soil organic matter. On the other hand, Se showed a significant association with clay and iron content. The concentration of Sb in soil exceeded the recommended value for agricultural use in 70% of the urban gardens. A human health risk assessment resulted in acceptable levels of both noncarcinogenic and carcinogenic risks (although with elevated values of the latter), with As as the main risk driver and soil and food ingestion as the main exposure pathways. The numerical results of the risk assessment should be interpreted with caution given the considerable uncertainties in some exposure variables and the lack of quantitative values for the suspected carcinogenicity of Sb and Se. Environ Toxicol Chem 2017;36:544-550. © 2016 SETAC. © 2016 SETAC.

Development of an agricultural job-exposure matrix for British Columbia, Canada.

PubMed

Wood, David; Astrakianakis, George; Lang, Barbara; Le, Nhu; Bert, Joel

2002-09-01

Farmers in British Columbia (BC), Canada have been shown to have unexplained elevated proportional mortality rates for several cancers. Because agricultural exposures have never been documented systematically in BC, a quantitative agricultural Job-exposure matrix (JEM) was developed containing exposure assessments from 1950 to 1998. This JEM was developed to document historical exposures and to facilitate future epidemiological studies. Available information regarding BC farming practices was compiled and checklists of potential exposures were produced for each crop. Exposures identified included chemical, biological, and physical agents. Interviews with farmers and agricultural experts were conducted using the checklists as a starting point. This allowed the creation of an initial or 'potential' JEM based on three axes: exposure agent, 'type of work' and time. The 'type of work' axis was determined by combining several variables: region, crop, job title and task. This allowed for a complete description of exposures. Exposure assessments were made quantitatively, where data allowed, or by a dichotomous variable (exposed/unexposed). Quantitative calculations were divided into re-entry and application scenarios. 'Re-entry' exposures were quantified using a standard exposure model with some modification while application exposure estimates were derived using data from the North American Pesticide Handlers Exposure Database (PHED). As expected, exposures differed between crops and job titles both quantitatively and qualitatively. Of the 290 agents included in the exposure axis; 180 were pesticides. Over 3000 estimates of exposure were conducted; 50% of these were quantitative. Each quantitative estimate was at the daily absorbed dose level. Exposure estimates were then rated as high, medium, or low based on comparing them with their respective oral chemical reference dose (RfD) or Acceptable Daily Intake (ADI). This data was mainly obtained from the US Environmental Protection Agency (EPA) Integrated Risk Information System database. Of the quantitative estimates, 74% were rated as low (< 100%) and only 10% were rated as high (>500%). The JEM resulting from this study fills a void concerning exposures for BC farmers and farm workers. While only limited validation of assessments were possible, this JEM can serve as a benchmark for future studies. Preliminary analysis at the BC Cancer Agency (BCCA) using the JEM with prostate cancer records from a large cancer and occupation study/survey has already shown promising results. Development of this JEM provides a useful model for developing historical quantitative exposure estimates where is very little documented information available.

Survey of patulin occurrence in apple juice and apple products in Catalonia, Spain, and an estimate of dietary intake.

PubMed

Cano-Sancho, G; Marin, S; Ramos, A J; Sanchis, V

2009-01-01

This study was conducted to assess patulin exposure in the Catalonian population. Patulin levels were determined in 161 apple juice samples, 77 solid apple-based food samples and 146 apple-based baby food samples obtained from six hypermarkets and supermarkets from twelve main cities of Catalonia, Spain. Patulin was analysed by a well-established validated method involving ethyl acetate extraction and direct analysis by high-performance liquid chromatography (HPLC) with ultraviolet light detection. Mean patulin levels for positive samples in apple juice, solid apple-based food and apple-based baby food were 8.05, 13.54 and 7.12 µg kg(-1), respectively. No samples exceeded the maximum permitted levels established by European Union regulation. Dietary intake was separately assessed for babies, infants and adults through a Food Frequency Questionnaire developed from 1056 individuals from Catalonia. Babies were the main group exposed to patulin, however no risk was detected at these levels of contamination. Adults and infants consumers were far from risk levels. Another approach to determine estimated exposure was conducted through Monte Carlo simulation that distinguishes variability in exposures from uncertainty of distributional parameter estimates.

Testing the coherence between occupational exposure limits for inhalation and their biological limit values with a generalized PBPK-model: the case of 2-propanol and acetone.

PubMed

Huizer, Daan; Huijbregts, Mark A J; van Rooij, Joost G M; Ragas, Ad M J

2014-08-01

The coherence between occupational exposure limits (OELs) and their corresponding biological limit values (BLVs) was evaluated for 2-propanol and acetone. A generic human PBPK model was used to predict internal concentrations after inhalation exposure at the level of the OEL. The fraction of workers with predicted internal concentrations lower than the BLV, i.e. the 'false negatives', was taken as a measure for incoherence. The impact of variability and uncertainty in input parameters was separated by means of nested Monte Carlo simulation. Depending on the exposure scenario considered, the median fraction of the population for which the limit values were incoherent ranged from 2% to 45%. Parameter importance analysis showed that body weight was the main factor contributing to interindividual variability in blood and urine concentrations and that the metabolic parameters Vmax and Km were the most important sources of uncertainty. This study demonstrates that the OELs and BLVs for 2-propanol and acetone are not fully coherent, i.e. enforcement of BLVs may result in OELs being violated. In order to assess the acceptability of this "incoherence", a maximum population fraction at risk of exceeding the OEL should be specified as well as a minimum level of certainty in predicting this fraction. Copyright © 2014 Elsevier Inc. All rights reserved.

Detection of major climatic and environmental predictors of liver fluke exposure risk in Ireland using spatial cluster analysis.

PubMed

Selemetas, Nikolaos; de Waal, Theo

2015-04-30

Fasciolosis caused by Fasciola hepatica (liver fluke) can cause significant economic and production losses in dairy cow farms. The aim of the current study was to identify important weather and environmental predictors of the exposure risk to liver fluke by detecting clusters of fasciolosis in Ireland. During autumn 2012, bulk-tank milk samples from 4365 dairy farms were collected throughout Ireland. Using an in-house antibody-detection ELISA, the analysis of BTM samples showed that 83% (n=3602) of dairy farms had been exposed to liver fluke. The Getis-Ord Gi* statistic identified 74 high-risk and 130 low-risk significant (P<0.01) clusters of fasciolosis. The low-risk clusters were mostly located in the southern regions of Ireland, whereas the high-risk clusters were mainly situated in the western part. Several climatic variables (monthly and seasonal mean rainfall and temperatures, total wet days and rain days) and environmental datasets (soil types, enhanced vegetation index and normalised difference vegetation index) were used to investigate dissimilarities in the exposure to liver fluke between clusters. Rainfall, total wet days and rain days, and soil type were the significant classes of climatic and environmental variables explaining the differences between significant clusters. A discriminant function analysis was used to predict the exposure risk to liver fluke using 80% of data for modelling and the remaining subset of 20% for post hoc model validation. The most significant predictors of the model risk function were total rainfall in August and September and total wet days. The risk model presented 100% sensitivity and 91% specificity and an accuracy of 95% correctly classified cases. A risk map of exposure to liver fluke was constructed with higher probability of exposure in western and north-western regions. The results of this study identified differences between clusters of fasciolosis in Ireland regarding climatic and environmental variables and detected significant predictors of the exposure risk to liver fluke. Copyright © 2015 Elsevier B.V. All rights reserved.

Diesel Exhaust Exposure and Nasal Response to Attenuated Influenza in Normal and Allergic Volunteers

PubMed Central

Zhou, Haibo; Zhang, Hongtao; Horvath, Katie; Robinette, Carole; Kesic, Matthew; Meyer, Megan; Diaz-Sanchez, David; Jaspers, Ilona

2012-01-01

Rationale: Diesel exhaust enhances allergic inflammation, and pollutants are associated with heightened susceptibility to viral respiratory infections. The effects of combined diesel and virus exposure in humans are unknown. Objectives: Test whether acute exposure to diesel modifies inflammatory responses to influenza virus in normal humans and those with allergies. Methods: We conducted a double-blind, randomized, placebo-controlled study of nasal responses to live attenuated influenza virus in normal volunteers and those with allergic rhinitis exposed to diesel (100 μg/m3) or clean air for 2 hours, followed by standard dose of virus and serial nasal lavages. Endpoints were inflammatory mediators (ELISA) and virus quantity (quantitative reverse-transcriptase polymerase chain reaction). To test for exposure effect, we used multiple regression with exposure group (diesel vs. air) as the main explanatory variable and allergic status as an additional factor. Measurements and Main Results: Baseline levels of mediators did not differ among groups. For most postvirus nasal cytokine responses, there was no significant diesel effect, and no significant interaction with allergy. However, diesel was associated with significantly increased IFN-γ responses (P = 0.02), with no interaction with allergy in the regression model. Eotaxin-1 (P = 0.01), eosinophil cationic protein (P < 0.01), and influenza RNA sequences in nasal cells (P = 0.03) were significantly increased with diesel exposure, linked to allergy. Conclusions: Short-term exposure to diesel exhaust leads to increased eosinophil activation and increased virus quantity after virus inoculation in those with allergic rhinitis. This is consistent with previous literature suggesting a diesel “adjuvant” effect promoting allergic inflammation, and our data further suggest this change may be associated with reduced virus clearance. Clinical trial registered with www.clinicaltrials.gov (NCT00617110). PMID:22071326

Spatial Distribution of Stony Desertification and Key Influencing Factors on Different Sampling Scales in Small Karst Watersheds

PubMed Central

Zhang, Zhenming; Zhou, Yunchao; Wang, Shijie

2018-01-01

Karst areas are typical ecologically fragile areas, and stony desertification has become the most serious ecological and economic problems in these areas worldwide as well as a source of disasters and poverty. A reasonable sampling scale is of great importance for research on soil science in karst areas. In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in karst areas are studied at different sampling scales using a grid sampling method based on geographic information system (GIS) technology and geo-statistics. The rock exposure obtained through sampling over a 150 m × 150 m grid in the Houzhai River Basin was utilized as the original data, and five grid scales (300 m × 300 m, 450 m × 450 m, 600 m × 600 m, 750 m × 750 m, and 900 m × 900 m) were used as the subsample sets. The results show that the rock exposure does not vary substantially from one sampling scale to another, while the average values of the five subsamples all fluctuate around the average value of the entire set. As the sampling scale increases, the maximum value and the average value of the rock exposure gradually decrease, and there is a gradual increase in the coefficient of variability. At the scale of 150 m × 150 m, the areas of minor stony desertification, medium stony desertification, and major stony desertification in the Houzhai River Basin are 7.81 km2, 4.50 km2, and 1.87 km2, respectively. The spatial variability of stony desertification at small scales is influenced by many factors, and the variability at medium scales is jointly influenced by gradient, rock content, and rock exposure. At large scales, the spatial variability of stony desertification is mainly influenced by soil thickness and rock content. PMID:29652811

Spatial Distribution of Stony Desertification and Key Influencing Factors on Different Sampling Scales in Small Karst Watersheds.

PubMed

Zhang, Zhenming; Zhou, Yunchao; Wang, Shijie; Huang, Xianfei

2018-04-13

Karst areas are typical ecologically fragile areas, and stony desertification has become the most serious ecological and economic problems in these areas worldwide as well as a source of disasters and poverty. A reasonable sampling scale is of great importance for research on soil science in karst areas. In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in karst areas are studied at different sampling scales using a grid sampling method based on geographic information system (GIS) technology and geo-statistics. The rock exposure obtained through sampling over a 150 m × 150 m grid in the Houzhai River Basin was utilized as the original data, and five grid scales (300 m × 300 m, 450 m × 450 m, 600 m × 600 m, 750 m × 750 m, and 900 m × 900 m) were used as the subsample sets. The results show that the rock exposure does not vary substantially from one sampling scale to another, while the average values of the five subsamples all fluctuate around the average value of the entire set. As the sampling scale increases, the maximum value and the average value of the rock exposure gradually decrease, and there is a gradual increase in the coefficient of variability. At the scale of 150 m × 150 m, the areas of minor stony desertification, medium stony desertification, and major stony desertification in the Houzhai River Basin are 7.81 km², 4.50 km², and 1.87 km², respectively. The spatial variability of stony desertification at small scales is influenced by many factors, and the variability at medium scales is jointly influenced by gradient, rock content, and rock exposure. At large scales, the spatial variability of stony desertification is mainly influenced by soil thickness and rock content.

Efficient Variable Selection Method for Exposure Variables on Binary Data

NASA Astrophysics Data System (ADS)

Ohno, Manabu; Tarumi, Tomoyuki

In this paper, we propose a new variable selection method for "robust" exposure variables. We define "robust" as property that the same variable can select among original data and perturbed data. There are few studies of effective for the selection method. The problem that selects exposure variables is almost the same as a problem that extracts correlation rules without robustness. [Brin 97] is suggested that correlation rules are possible to extract efficiently using chi-squared statistic of contingency table having monotone property on binary data. But the chi-squared value does not have monotone property, so it's is easy to judge the method to be not independent with an increase in the dimension though the variable set is completely independent, and the method is not usable in variable selection for robust exposure variables. We assume anti-monotone property for independent variables to select robust independent variables and use the apriori algorithm for it. The apriori algorithm is one of the algorithms which find association rules from the market basket data. The algorithm use anti-monotone property on the support which is defined by association rules. But independent property does not completely have anti-monotone property on the AIC of independent probability model, but the tendency to have anti-monotone property is strong. Therefore, selected variables with anti-monotone property on the AIC have robustness. Our method judges whether a certain variable is exposure variable for the independent variable using previous comparison of the AIC. Our numerical experiments show that our method can select robust exposure variables efficiently and precisely.

Study for Promotion of Health in Recycling Lead - Rationale and design.

PubMed

Hara, Azusa; Gu, Yu-Mei; Petit, Thibault; Liu, Yan-Ping; Jacobs, Lotte; Zhang, Zhen-Yu; Yang, Wen-Yi; Jin, Yu; Thijs, Lutgarde; Wei, Fang-Fei; Nawrot, Tim S; Staessen, Jan A

2015-06-01

The level at which low-level lead exposure produces subclinical adverse health effects in adults remains to be established. The Study for Promotion of Health in Recycling Lead (SPHERL) will enroll 500 newly hired workers, whose blood lead during 2 years of follow-up is expected to increase from levels less than 2 μg/dl, as currently observed in the US population, to 20-30 μg/dl. The main outcome variables to be studied are (i) blood pressure (BP) analyzed as a continuous or categorical variable, both cross-sectionally and longitudinally, and using conventional and ambulatory BP measurement; (ii) indexes of glomerular and tubular renal function, (iii) heart rate variability analyzed in the frequency domain as measure of autonomous sympathetic modulation, (iv) peripheral nerve conductivity velocity, (v) neurocognitive performance, and (vi) quality of life. Expected outcomes. Assuming a 10-fold increase in blood lead, SPHERL will have sufficient statistical power to detect over 2 years a steepening of the age-related rise in systolic BP from 1 to 5 mmHg and a doubling of the age-related decline in the estimated glomerular filtration rate from 3.5 to 7.0 ml/min/1.73 m(2). The longitudinal design of our study complies with the temporality principle of the Bradford-Hill criteria for assessing possible causality between outcomes and exposure. SPHERL will attempt to resolve the apparent contradiction between general population studies showing associations between adverse health effects and low lead exposure with blood lead levels below 5 μg/dl and studies conducted in occupational cohorts indicating that adverse effects of lead exposure occur at much higher blood lead levels.

What can we know from pituitary-adrenal hormones about the nature and consequences of exposure to emotional stressors?

PubMed

Armario, Antonio; Daviu, Núria; Muñoz-Abellán, Cristina; Rabasa, Cristina; Fuentes, Silvia; Belda, Xavier; Gagliano, Humberto; Nadal, Roser

2012-07-01

Exposure to stress induces profound physiological and behavioral changes in the organisms and some of these changes may be important regarding stress-induced pathologies and animal models of psychiatric diseases. Consequences of stress are dependent on the duration of exposure to stressors (acute, chronic), but also of certain characteristics such as intensity, controllability, and predictability. If some biological variables were able to reflect these characteristics, they could be used to predict negative consequences of stress. Among the myriad of physiological changes caused by stress, only a restricted number of variables appears to reflect the intensity of the situation, mainly plasma levels of ACTH and adrenaline. Peripheral hypothalamic-pituitary-adrenal (HPA) hormones (ACTH and corticosterone) are also able to reflect fear conditioning. In contrast, the activation of the HPA axis is not consistently related to anxiety as evaluated by classical tests such as the elevated plus-maze. Similarly, there is no consistent evidence about the sensitivity of the HPA axis to psychological variables such as controllability and predictability, despite the fact that: (a) lack of control over aversive stimuli can induce behavioral alterations not seen in animals which exert control, and (b) animals showed clear preference for predictable versus unpredictable stressful situations. New studies are needed to re-evaluate the relationship between the HPA axis and psychological stress characteristics using ACTH instead of corticosterone and taking advantages of our current knowledge about the regulation of this important stress system.

POPULATION-BASED EXPOSURE MODELING FOR AIR POLLUTANTS AT EPA'S NATIONAL EXPOSURE RESEARCH LABORATORY

EPA Science Inventory

The US EPA's National Exposure Research Laboratory (NERL) has been developing, applying, and evaluating population-based exposure models to improve our understanding of the variability in personal exposure to air pollutants. Estimates of population variability are needed for E...

Trends in oral drug bioavailability following bariatric surgery: examining the variable extent of impact on exposure of different drug classes

PubMed Central

Darwich, Adam S; Henderson, Kathryn; Burgin, Angela; Ward, Nicola; Whittam, Janet; Ammori, Basil J; Ashcroft, Darren M; Rostami-Hodjegan, Amin

2012-01-01

AIMS To identify the most commonly prescribed drugs in a bariatric surgery population and to assess existing evidence regarding trends in oral drug bioavailability post bariatric surgery. METHODS A retrospective audit was undertaken to document commonly prescribed drugs amongst patients undergoing bariatric surgery in an NHS hospital in the UK and to assess practice for drug administration following bariatric surgery. The available literature was examined for trends relating to drug permeability and solubility with regards to the Biopharmaceutics Classification System (BCS) and main route of elimination. RESULTS No significant difference in the ‘post/pre surgery oral drug exposure ratio’ (ppR) was apparent between BCS class I to IV drugs, with regards to dose number (Do) or main route of elimination. Drugs classified as ‘solubility limited’ displayed an overall reduction as compared with ‘freely soluble’ compounds, as well as an unaltered and increased ppR. CONCLUSION Clinical studies establishing guidelines for commonly prescribed drugs, and the monitoring of drugs exhibiting a narrow therapeutic window or without a readily assessed clinical endpoint, are warranted. Using mechanistically based pharmacokinetic modelling for simulating the multivariate nature of changes in drug exposure may serve as a useful tool in the further understanding of postoperative trends in oral drug exposure and in developing practical clinical guidance. PMID:22463107

Persistent erectile dysfunction in men exposed to the 5α-reductase inhibitors, finasteride, or dutasteride

PubMed Central

Yarnold, Paul R.; Cashy, John; Brannigan, Robert E.; Nardone, Beatrice; Micali, Giuseppe; West, Dennis Paul

2017-01-01

Importance Case reports describe persistent erectile dysfunction (PED) associated with exposure to 5α-reductase inhibitors (5α-RIs). Clinical trial reports and the manufacturers’ full prescribing information (FPI) for finasteride and dutasteride state that risk of sexual adverse effects is not increased by longer duration of 5α-RI exposure and that sexual adverse effects of 5α-RIs resolve in men who discontinue exposure. Objective Our chief objective was to assess whether longer duration of 5α-RI exposure increases risk of PED, independent of age and other known risk factors. Men with shorter 5α-RI exposure served as a comparison control group for those with longer exposure. Design We used a single-group study design and classification tree analysis (CTA) to model PED (lasting ≥90 days after stopping 5α-RI). Covariates included subject attributes, diseases, and drug exposures associated with sexual dysfunction. Setting Our data source was the electronic medical record data repository for Northwestern Medicine. Subjects The analysis cohorts comprised all men exposed to finasteride or dutasteride or combination products containing one of these drugs, and the subgroup of men 16–42 years old and exposed to finasteride ≤1.25 mg/day. Main outcome and measures Our main outcome measure was diagnosis of PED beginning after first 5α-RI exposure, continuing for at least 90 days after stopping 5α-RI, and with contemporaneous treatment with a phosphodiesterase-5 inhibitor (PDE5I). Other outcome measures were erectile dysfunction (ED) and low libido. PED was determined by manual review of medical narratives for all subjects with ED. Risk of an adverse effect was expressed as number needed to harm (NNH). Results Among men with 5α-RI exposure, 167 of 11,909 (1.4%) developed PED (persistence median 1,348 days after stopping 5α-RI, interquartile range (IQR) 631.5–2320.5 days); the multivariable model predicting PED had four variables: prostate disease, duration of 5α-RI exposure, age, and nonsteroidal anti-inflammatory drug (NSAID) use. Of 530 men with new ED, 167 (31.5%) had new PED. Men without prostate disease who combined NSAID use with >208.5 days of 5α-RI exposure had 4.8-fold higher risk of PED than men with shorter exposure (NNH 59.8, all p < 0.002). Among men 16–42 years old and exposed to finasteride ≤1.25 mg/day, 34 of 4,284 (0.8%) developed PED (persistence median 1,534 days, IQR 651–2,351 days); the multivariable model predicting PED had one variable: duration of 5α-RI exposure. Of 103 young men with new ED, 34 (33%) had new PED. Young men with >205 days of finasteride exposure had 4.9-fold higher risk of PED (NNH 108.2, p < 0.004) than men with shorter exposure. Conclusion and relevance Risk of PED was higher in men with longer exposure to 5α-RIs. Among young men, longer exposure to finasteride posed a greater risk of PED than all other assessed risk factors. PMID:28289563

Identification of the significant factors in food safety using global sensitivity analysis and the accept-and-reject algorithm: application to the cold chain of ham.

PubMed

Duret, Steven; Guillier, Laurent; Hoang, Hong-Minh; Flick, Denis; Laguerre, Onrawee

2014-06-16

Deterministic models describing heat transfer and microbial growth in the cold chain are widely studied. However, it is difficult to apply them in practice because of several variable parameters in the logistic supply chain (e.g., ambient temperature varying due to season and product residence time in refrigeration equipment), the product's characteristics (e.g., pH and water activity) and the microbial characteristics (e.g., initial microbial load and lag time). This variability can lead to different bacterial growth rates in food products and has to be considered to properly predict the consumer's exposure and identify the key parameters of the cold chain. This study proposes a new approach that combines deterministic (heat transfer) and stochastic (Monte Carlo) modeling to account for the variability in the logistic supply chain and the product's characteristics. The model generates a realistic time-temperature product history , contrary to existing modeling whose describe time-temperature profile Contrary to existing approaches that use directly a time-temperature profile, the proposed model predicts product temperature evolution from the thermostat setting and the ambient temperature. The developed methodology was applied to the cold chain of cooked ham including, the display cabinet, transport by the consumer and the domestic refrigerator, to predict the evolution of state variables, such as the temperature and the growth of Listeria monocytogenes. The impacts of the input factors were calculated and ranked. It was found that the product's time-temperature history and the initial contamination level are the main causes of consumers' exposure. Then, a refined analysis was applied, revealing the importance of consumer behaviors on Listeria monocytogenes exposure. Copyright © 2014. Published by Elsevier B.V.

Health Impacts of the Built Environment: Within-Urban Variability in Physical Inactivity, Air Pollution, and Ischemic Heart Disease Mortality

PubMed Central

Hankey, Steve; Brauer, Michael

2011-01-01

Background: Physical inactivity and exposure to air pollution are important risk factors for death and disease globally. The built environment may influence exposures to these risk factors in different ways and thus differentially affect the health of urban populations. Objective: We investigated the built environment’s association with air pollution and physical inactivity, and estimated attributable health risks. Methods: We used a regional travel survey to estimate within-urban variability in physical inactivity and home-based air pollution exposure [particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5), nitrogen oxides (NOx), and ozone (O3)] for 30,007 individuals in southern California. We then estimated the resulting risk for ischemic heart disease (IHD) using literature-derived dose–response values. Using a cross-sectional approach, we compared estimated IHD mortality risks among neighborhoods based on “walkability” scores. Results: The proportion of physically active individuals was higher in high- versus low-walkability neighborhoods (24.9% vs. 12.5%); however, only a small proportion of the population was physically active, and between-neighborhood variability in estimated IHD mortality attributable to physical inactivity was modest (7 fewer IHD deaths/100,000/year in high- vs. low-walkability neighborhoods). Between-neighborhood differences in estimated IHD mortality from air pollution were comparable in magnitude (9 more IHD deaths/100,000/year for PM2.5 and 3 fewer IHD deaths for O3 in high- vs. low-walkability neighborhoods), suggesting that population health benefits from increased physical activity in high-walkability neighborhoods may be offset by adverse effects of air pollution exposure. Policy implications: Currently, planning efforts mainly focus on increasing physical activity through neighborhood design. Our results suggest that differences in population health impacts among neighborhoods are similar in magnitude for air pollution and physical activity. Thus, physical activity and exposure to air pollution are critical aspects of planning for cleaner, health-promoting cities. PMID:22004949

Health impacts of the built environment: within-urban variability in physical inactivity, air pollution, and ischemic heart disease mortality.

PubMed

Hankey, Steve; Marshall, Julian D; Brauer, Michael

2012-02-01

Physical inactivity and exposure to air pollution are important risk factors for death and disease globally. The built environment may influence exposures to these risk factors in different ways and thus differentially affect the health of urban populations. We investigated the built environment's association with air pollution and physical inactivity, and estimated attributable health risks. We used a regional travel survey to estimate within-urban variability in physical inactivity and home-based air pollution exposure [particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5), nitrogen oxides (NOx), and ozone (O3)] for 30,007 individuals in southern California. We then estimated the resulting risk for ischemic heart disease (IHD) using literature-derived dose-response values. Using a cross-sectional approach, we compared estimated IHD mortality risks among neighborhoods based on "walkability" scores. The proportion of physically active individuals was higher in high- versus low-walkability neighborhoods (24.9% vs. 12.5%); however, only a small proportion of the population was physically active, and between-neighborhood variability in estimated IHD mortality attributable to physical inactivity was modest (7 fewer IHD deaths/100,000/year in high- vs. low-walkability neighborhoods). Between-neighborhood differences in estimated IHD mortality from air pollution were comparable in magnitude (9 more IHD deaths/100,000/year for PM2.5 and 3 fewer IHD deaths for O3 in high- vs. low-walkability neighborhoods), suggesting that population health benefits from increased physical activity in high-walkability neighborhoods may be offset by adverse effects of air pollution exposure. Currently, planning efforts mainly focus on increasing physical activity through neighborhood design. Our results suggest that differences in population health impacts among neighborhoods are similar in magnitude for air pollution and physical activity. Thus, physical activity and exposure to air pollution are critical aspects of planning for cleaner, health-promoting cities.

The effects of a hearing education program on recreational noise exposure, attitudes and beliefs toward noise, hearing loss, and hearing protector devices in young adults.

PubMed

Keppler, Hannah; Ingeborg, Dhooge; Sofie, Degeest; Bart, Vinck

2015-01-01

Excessive recreational noise exposure in young adults might result in noise-induced hearing loss (NIHL) and tinnitus. Inducing behavioral change in young adults is one of the aims of a hearing conservation program (HCP). The goal of the current study was to evaluate the effect of a hearing education program after 6 months in young adults in relation to knowledge regarding their individual hearing status. The results of a questionnaire regarding the weekly equivalent recreational noise exposure, attitudes and beliefs toward noise, and hearing loss and hearing protector devices (HPDs) were compared between both sessions. Seventy-eight young adults completed the questionnaire concerning recreational noise exposure, youth attitude to noise scale (YANS), and beliefs about hearing protection and hearing loss (BAHPHL). Their hearing status was evaluated based on admittance measures, audiometry, transient-evoked otoacoustic emissions (TEOAEs), and distortion-product otoacoustic emissions (DPOAEs). The main analysis consisted of a mixed model analysis of variance with dependent variables of either the noise exposure or the scores on (subscales of) YANS and BAHPHL. The independent variables were hearing status and session one versus session two. There was a significant decrease in recreational noise exposure and several (sub) scales of YANS and BAHPHL between both the sessions. This behavioral change resulted in a more frequent use of HPDs in 12% of the participants. However, the behavioral change was not completely related to the knowledge of young adults' individual hearing status. To prevent hearing damage in young people, investing in HCPs is necessary, apart from regulating sound levels and its compliance at various leisure-time activities. Also, the long-term effect of HCPs and their most cost-efficient repetition rates should be further investigated.

Negative control exposure studies in the presence of measurement error: implications for attempted effect estimate calibration

PubMed Central

Sanderson, Eleanor; Macdonald-Wallis, Corrie; Davey Smith, George

2018-01-01

Abstract Background Negative control exposure studies are increasingly being used in epidemiological studies to strengthen causal inference regarding an exposure-outcome association when unobserved confounding is thought to be present. Negative control exposure studies contrast the magnitude of association of the negative control, which has no causal effect on the outcome but is associated with the unmeasured confounders in the same way as the exposure, with the magnitude of the association of the exposure with the outcome. A markedly larger effect of the exposure on the outcome than the negative control on the outcome strengthens inference that the exposure has a causal effect on the outcome. Methods We investigate the effect of measurement error in the exposure and negative control variables on the results obtained from a negative control exposure study. We do this in models with continuous and binary exposure and negative control variables using analysis of the bias of the estimated coefficients and Monte Carlo simulations. Results Our results show that measurement error in either the exposure or negative control variables can bias the estimated results from the negative control exposure study. Conclusions Measurement error is common in the variables used in epidemiological studies; these results show that negative control exposure studies cannot be used to precisely determine the size of the effect of the exposure variable, or adequately adjust for unobserved confounding; however, they can be used as part of a body of evidence to aid inference as to whether a causal effect of the exposure on the outcome is present. PMID:29088358

Negative control exposure studies in the presence of measurement error: implications for attempted effect estimate calibration.

PubMed

Sanderson, Eleanor; Macdonald-Wallis, Corrie; Davey Smith, George

2018-04-01

Negative control exposure studies are increasingly being used in epidemiological studies to strengthen causal inference regarding an exposure-outcome association when unobserved confounding is thought to be present. Negative control exposure studies contrast the magnitude of association of the negative control, which has no causal effect on the outcome but is associated with the unmeasured confounders in the same way as the exposure, with the magnitude of the association of the exposure with the outcome. A markedly larger effect of the exposure on the outcome than the negative control on the outcome strengthens inference that the exposure has a causal effect on the outcome. We investigate the effect of measurement error in the exposure and negative control variables on the results obtained from a negative control exposure study. We do this in models with continuous and binary exposure and negative control variables using analysis of the bias of the estimated coefficients and Monte Carlo simulations. Our results show that measurement error in either the exposure or negative control variables can bias the estimated results from the negative control exposure study. Measurement error is common in the variables used in epidemiological studies; these results show that negative control exposure studies cannot be used to precisely determine the size of the effect of the exposure variable, or adequately adjust for unobserved confounding; however, they can be used as part of a body of evidence to aid inference as to whether a causal effect of the exposure on the outcome is present.

Spatial analysis of trace elements in a moss bio-monitoring data over France by accounting for source, protocol and environmental parameters.

PubMed

Lequy, Emeline; Saby, Nicolas P A; Ilyin, Ilia; Bourin, Aude; Sauvage, Stéphane; Leblond, Sébastien

2017-07-15

Air pollution in trace elements (TE) remains a concern for public health in Europe. For this reasons, networks of air pollution concentrations or exposure are deployed, including a moss bio-monitoring programme in Europe. Spatial determinants of TE concentrations in mosses remain unclear. In this study, the French dataset of TE in mosses is analyzed by spatial autoregressive model to account for spatial structure of the data and several variables proven or suspected to affect TE concentrations in mosses. Such variables include source (atmospheric deposition and soil concentrations), protocol (sampling month, collector, and moss species), and environment (forest type and canopy density, distance to the coast or the highway, and elevation). Modeled atmospheric deposition was only available for Cd and Pb and was one of the main explanatory variables of the concentrations in mosses. Predicted soil content was also an important explanatory variable except for Cr, Ni, and Zn. However, the moss species was the main factor for all the studied TE. The other environmental variables affected differently the TE. In particular, the forest type and canopy density were important in most cases. These results stress the need for further research on the effect of the moss species on the capture and retention of TE, as well as for accounting for several variables and the spatial structure of the data in statistical analyses. Copyright © 2017 Elsevier B.V. All rights reserved.

A Novel Approach to model EPIC variable background

NASA Astrophysics Data System (ADS)

Marelli, M.; De Luca, A.; Salvetti, D.; Belfiore, A.

2017-10-01

One of the main aim of the EXTraS (Exploring the X-ray Transient and variable Sky) project is to characterise the variability of serendipitous XMM-Newton sources within each single observation. Unfortunately, 164 Ms out of the 774 Ms of cumulative exposure considered (21%) are badly affected by soft proton flares, hampering any classical analysis of field sources. De facto, the latest releases of the 3XMM catalog, as well as most of the analysis in literature, simply exclude these 'high background' periods from analysis. We implemented a novel SAS-indipendent approach to produce background-subtracted light curves, which allows to treat the case of very faint sources and very bright proton flares. EXTraS light curves of 3XMM-DR5 sources will be soon released to the community, together with new tools we are developing.

Systematically extracting metal- and solvent-related occupational information from free-text responses to lifetime occupational history questionnaires.

PubMed

Friesen, Melissa C; Locke, Sarah J; Tornow, Carina; Chen, Yu-Cheng; Koh, Dong-Hee; Stewart, Patricia A; Purdue, Mark; Colt, Joanne S

2014-06-01

Lifetime occupational history (OH) questionnaires often use open-ended questions to capture detailed information about study participants' jobs. Exposure assessors use this information, along with responses to job- and industry-specific questionnaires, to assign exposure estimates on a job-by-job basis. An alternative approach is to use information from the OH responses and the job- and industry-specific questionnaires to develop programmable decision rules for assigning exposures. As a first step in this process, we developed a systematic approach to extract the free-text OH responses and convert them into standardized variables that represented exposure scenarios. Our study population comprised 2408 subjects, reporting 11991 jobs, from a case-control study of renal cell carcinoma. Each subject completed a lifetime OH questionnaire that included verbatim responses, for each job, to open-ended questions including job title, main tasks and activities (task), tools and equipment used (tools), and chemicals and materials handled (chemicals). Based on a review of the literature, we identified exposure scenarios (occupations, industries, tasks/tools/chemicals) expected to involve possible exposure to chlorinated solvents, trichloroethylene (TCE) in particular, lead, and cadmium. We then used a SAS macro to review the information reported by study participants to identify jobs associated with each exposure scenario; this was done using previously coded standardized occupation and industry classification codes, and a priori lists of associated key words and phrases related to possibly exposed tasks, tools, and chemicals. Exposure variables representing the occupation, industry, and task/tool/chemicals exposure scenarios were added to the work history records of the study respondents. Our identification of possibly TCE-exposed scenarios in the OH responses was compared to an expert's independently assigned probability ratings to evaluate whether we missed identifying possibly exposed jobs. Our process added exposure variables for 52 occupation groups, 43 industry groups, and 46 task/tool/chemical scenarios to the data set of OH responses. Across all four agents, we identified possibly exposed task/tool/chemical exposure scenarios in 44-51% of the jobs in possibly exposed occupations. Possibly exposed task/tool/chemical exposure scenarios were found in a nontrivial 9-14% of the jobs not in possibly exposed occupations, suggesting that our process identified important information that would not be captured using occupation alone. Our extraction process was sensitive: for jobs where our extraction of OH responses identified no exposure scenarios and for which the sole source of information was the OH responses, only 0.1% were assessed as possibly exposed to TCE by the expert. Our systematic extraction of OH information found useful information in the task/chemicals/tools responses that was relatively easy to extract and that was not available from the occupational or industry information. The extracted variables can be used as inputs in the development of decision rules, especially for jobs where no additional information, such as job- and industry-specific questionnaires, is available. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2014.

[Exposure pathways to pesticides in schoolchildren in the Province of Talca, Chile].

PubMed

Muñoz-Quezada, María Teresa; Lucero, Boris; Iglesias, Verónica; Muñoz, María Pía

2014-01-01

To describe pesticide concentrations in distinct environmental matrices at two time points (low and high seasons in local agricultural production) and to estimate the association between the presence of pesticide residues in matrices and the use of pesticides in the home with the sociodemographic variables of schoolchildren in the Province of Talca, Chile. A cross-sectional study was conducted in 190 schoolchildren. Families were surveyed about their children's vegetable consumption in school and at home, the use of pesticides in the home, and other sociodemographic variables. Additionally, we measured pesticide residues in vegetables and water consumed by the schoolchildren and in the soil of 14 schools. At both time points, the vegetable matrix had the highest pesticide concentration, both in urban and rural schoolchildren. The most common pesticide residues in vegetables were chlorpyrifos, diphenylamine, pyrimethanil, and thiabendazole. In the home, pyrethroid and organophosphate pesticides were mainly used in summer. Dangerous pesticide residues such as azinphos methyl and dimethoate were found in vegetables consumed by the children in schools and households, and organochlorines were found in the soil in some schools. Pesticide exposure should be limited and the health effects related to pesticide exposure should be assessed in the school population. Copyright © 2013 SESPAS. Published by Elsevier Espana. All rights reserved.

Do outdoor environmental noise and atmospheric NO2 levels spatially overlap in urban areas?

PubMed

Tenailleau, Quentin M; Bernard, Nadine; Pujol, Sophie; Parmentier, Anne-Laure; Boilleaut, Mathieu; Houot, Hélène; Joly, Daniel; Mauny, Frédéric

2016-07-01

The urban environment holds numerous emission sources for air and noise pollution, creating optimum conditions for environmental multi-exposure situations. Evaluation of the joint-exposure levels is the main obstacle for multi-exposure studies and one of the biggest challenges of the next decade. The present study aims to describe the noise/NO2 multi-exposure situations in the urban environment by exploring the possible discordant and concordant situations of both exposures. Fine-scale diffusion models were developed in the European medium-sized city of Besançon (France), and a classification method was used to evaluate the multi-exposure situations in the façade perimeter of 10,825 buildings. Although correlated (Pearson's r = 0.64, p < 0.01), urban spatial distributions of the noise and NO2 around buildings do not overlap, and 30% of the buildings were considered to be discordant in terms of the noise and NO2 exposure levels. This discrepancy is spatially structured and associated with variables describing the building's environment. Our results support the presence of several co-existing, multi-exposure situations across the city impacted by both the urban morphology and the emission and diffusion/propagation phases of each pollutant. Identifying the mechanisms of discrepancy and convergence of multi-exposure situations could help improve the health risk assessment and public health. Copyright © 2016 Elsevier Ltd. All rights reserved.

Land Use Regression Modeling of Outdoor Noise Exposure in Informal Settlements in Western Cape, South Africa.

PubMed

Sieber, Chloé; Ragettli, Martina S; Brink, Mark; Toyib, Olaniyan; Baatjies, Roslyn; Saucy, Apolline; Probst-Hensch, Nicole; Dalvie, Mohamed Aqiel; Röösli, Martin

2017-10-20

In low- and middle-income countries, noise exposure and its negative health effects have been little explored. The present study aimed to assess the noise exposure situation in adults living in informal settings in the Western Cape Province, South Africa. We conducted continuous one-week outdoor noise measurements at 134 homes in four different areas. These data were used to develop a land use regression (LUR) model to predict A-weighted day-evening-night equivalent sound levels (L den ) from geographic information system (GIS) variables. Mean noise exposure during day (6:00-18:00) was 60.0 A-weighted decibels (dB(A)) (interquartile range 56.9-62.9 dB(A)), during night (22:00-6:00) 52.9 dB(A) (49.3-55.8 dB(A)) and average L den was 63.0 dB(A) (60.1-66.5 dB(A)). Main predictors of the LUR model were related to road traffic and household density. Model performance was low (adjusted R 2 = 0.130) suggesting that other influences than those represented in the geographic predictors are relevant for noise exposure. This is one of the few studies on the noise exposure situation in low- and middle-income countries. It demonstrates that noise exposure levels are high in these settings.

Childhood Leukemia and 50 Hz Magnetic Fields: Findings from the Italian SETIL Case-Control Study

PubMed Central

Salvan, Alberto; Ranucci, Alessandra; Lagorio, Susanna; Magnani, Corrado

2015-01-01

We report on an Italian case-control study on childhood leukemia and exposure to extremely low frequency magnetic fields (ELF-MF). Eligible for inclusion were 745 leukemia cases, aged 0–10 years at diagnosis in 1998–2001, and 1475 sex- and age-matched population controls. Parents of 683 cases and 1044 controls (92% vs. 71%) were interviewed. ELF-MF measurements (24–48 h), in the child’s bedroom of the dwelling inhabited one year before diagnosis, were available for 412 cases and 587 controls included in the main conditional regression analyses. The magnetic field induction was 0.04 μT on average (geometric mean), with 0.6% of cases and 1.6% of controls exposed to >0.3 μT. The impact of changes in the statistical model, exposure metric, and data-set restriction criteria was explored via sensitivity analyses. No exposure-disease association was observed in analyses based on continuous exposure, while analyses based on categorical variables were characterized by incoherent exposure-outcome relationships. In conclusion, our results may be affected by several sources of bias and they are noninformative at exposure levels >0.3 μT. Nonetheless, the study may contribute to future meta- or pooled analyses. Furthermore, exposure levels among population controls are useful to estimate attributable risk. PMID:25689995

Inter-laboratory consistency and variability in the buccal micronucleus cytome assay depends on biomarker scored and laboratory experience: results from the HUMNxl international inter-laboratory scoring exercise.

PubMed

Bolognesi, Claudia; Knasmueller, Siegfried; Nersesyan, Armen; Roggieri, Paola; Ceppi, Marcello; Bruzzone, Marco; Blaszczyk, Ewa; Mielzynska-Svach, Danuta; Milic, Mirta; Bonassi, Stefano; Benedetti, Danieli; Da Silva, Juliana; Toledo, Raphael; Salvadori, Daisy Maria Fávero; Groot de Restrepo, Helena; Filipic, Metka; Hercog, Klara; Aktas, Ayça; Burgaz, Sema; Kundi, Michael; Grummt, Tamara; Thomas, Philip; Hor, Maryam; Escudero-Fung, Maria; Holland, Nina; Fenech, Michael

2017-03-01

The buccal micronucleus cytome (BMNcyt) assay in uncultured exfoliated epithelial cells from oral mucosa is widely applied in biomonitoring human exposures to genotoxic agents and is also proposed as a suitable test for prescreening and follow-up of precancerous oral lesions. The main limitation of the assay is the large variability observed in the baseline values of micronuclei (MNi) and other nuclear anomalies mainly related to different scoring criteria. The aim of this international collaborative study, involving laboratories with different level of experience, was to evaluate the inter- and intra-laboratory variations in the BMNcyt parameters, using recently implemented guidelines, in scoring cells from the same pooled samples obtained from healthy subjects (control group) and from cancer patients undergoing radiotherapy (treated group). The results indicate that all laboratories correctly discriminated samples from the two groups by a significant increase of micronucleus (MN) and nuclear bud (NBUD) frequencies and differentiated binucleated (BN) cells, associated with the exposure to ionizing radiation. The experience of the laboratories was shown to play an important role in the identification of the different cell types and nuclear anomalies. MN frequency in differentiated mononucleated (MONO) and BN cells showed the greatest consistency among the laboratories and low variability was also detected in the frequencies of MONO and BN cells. A larger variability was observed in classifying the different cell types, indicating the subjectivity in the interpretation of some of the scoring criteria while reproducibility of the results between scoring sessions was very good. An inter-laboratory calibration exercise is strongly recommended before starting studies with BMNcyt assay involving multiple research centers. © The Author 2016. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Variability in baseline travel behaviour as a predictor of changes in commuting by active travel, car and public transport: a natural experimental study

PubMed Central

Heinen, Eva; Ogilvie, David

2016-01-01

Purpose To strengthen our understanding of the impact of baseline variability in mode choice on the likelihood of travel behaviour change. Methods Quasi-experimental analyses in a cohort study of 450 commuters exposed to a new guided busway with a path for walking and cycling in Cambridge, UK. Exposure to the intervention was defined using the shortest network distance from each participant’s home to the busway. Variability in commuter travel behaviour at baseline was defined using the Herfindahl–Hirschman Index, the number of different modes of transport used over a week, and the proportion of trips made by the main (combination of) mode(s). The outcomes were changes in the share of commute trips (i) involving any active travel, (ii) involving any public transport, and (iii) made entirely by car. Variability and change data were derived from a self-reported seven-day record collected before (2009) and after (2012) the intervention. Separate multinomial regression models were estimated to assess the influence of baseline variability on behaviour change, both independently and as an interaction effect with exposure to the intervention. Results All three measures of variability predicted changes in mode share in most models. The effect size for the intervention was slightly strengthened after including variability. Commuters with higher baseline variability were more likely to increase their active mode share (e.g. for HHI: relative risk ratio [RRR] for interaction 3.34, 95% CI 1.41, 7.89) and decrease their car mode share in response to the intervention (e.g. for HHI: RRR 7.50, 95% CI 2.52, 22.34). Conclusions People reporting a higher level of variability in mode choice were more likely to change their travel behaviour following an intervention. Future research should consider such variability as a potential predictor and effect modifier of travel and physical activity behaviour change, and its significance for the design and targeting of interventions. PMID:27200265

Mentorship and job satisfaction among Navy family physicians.

PubMed

Saperstein, Adam K; Viera, Anthony J; Firnhaber, Gina C

2012-08-01

Among civilian academic physicians, having a mentor is associated with greater job satisfaction. Whether this is true for military physicians is unknown. We sought to examine whether having a mentor is associated with positive job satisfaction among Navy family physicians. A web-based survey was sent to all Navy family physicians in the Specialty leader's database in May 2008. Our main outcome variable was "positive job satisfaction," and our main exposure variable was being in a mentor relationship. Chi-square was used to test for difference in frequencies in categorical variables and logistic regression was used to adjust for covariates. The response rate was 60.2% (186/309). Among respondents, 73.7% reported positive job satisfaction. Factors associated with positive job satisfaction included having a mentor, being >9 years postresidency, spending <50% of time in patient care, higher rank, male gender, and being active in research. After adjustment for these factors, having a mentor remained significantly associated with positive job satisfaction (odds ratio 2.86, 95% confidence interval 1.22-6.71). Having a mentor is associated with positive job satisfaction among Navy family physicians, even after adjusting for multiple other factors. An implication is that a mentorship program may be a strategy for improving job satisfaction.

Quantitatively measured tremor in hand-arm vibration-exposed workers.

PubMed

Edlund, Maria; Burström, Lage; Hagberg, Mats; Lundström, Ronnie; Nilsson, Tohr; Sandén, Helena; Wastensson, Gunilla

2015-04-01

The aim of the present study was to investigate the possible increase in hand tremor in relation to hand-arm vibration (HAV) exposure in a cohort of exposed and unexposed workers. Participants were 178 male workers with or without exposure to HAV. The study is cross-sectional regarding the outcome of tremor and has a longitudinal design with respect to exposure. The dose of HAV exposure was collected via questionnaires and measurements at several follow-ups. The CATSYS Tremor Pen(®) was used for measuring postural tremor. Multiple linear regression methods were used to analyze associations between different tremor variables and HAV exposure, along with predictor variables with biological relevance. There were no statistically significant associations between the different tremor variables and cumulative HAV or current exposure. Age was a statistically significant predictor of variation in tremor outcomes for three of the four tremor variables, whereas nicotine use was a statistically significant predictor of either left or right hand or both hands for all four tremor variables. In the present study, there was no evidence of an exposure-response association between HAV exposure and measured postural tremor. Increase in age and nicotine use appeared to be the strongest predictors of tremor.

Interaction of childhood urbanicity and variation in dopamine genes alters adult prefrontal function as measured by functional magnetic resonance imaging (fMRI).

PubMed

Reed, Jessica L; D'Ambrosio, Enrico; Marenco, Stefano; Ursini, Gianluca; Zheutlin, Amanda B; Blasi, Giuseppe; Spencer, Barbara E; Romano, Raffaella; Hochheiser, Jesse; Reifman, Ann; Sturm, Justin; Berman, Karen F; Bertolino, Alessandro; Weinberger, Daniel R; Callicott, Joseph H

2018-01-01

Brain phenotypes showing environmental influence may help clarify unexplained associations between urban exposure and psychiatric risk. Heritable prefrontal fMRI activation during working memory (WM) is such a phenotype. We hypothesized that urban upbringing (childhood urbanicity) would alter this phenotype and interact with dopamine genes that regulate prefrontal function during WM. Further, dopamine has been hypothesized to mediate urban-associated factors like social stress. WM-related prefrontal function was tested for main effects of urbanicity, main effects of three dopamine genes-catechol-O-methyltransferase (COMT), dopamine receptor D1 (DRD1), and dopamine receptor D2 (DRD2)-and, importantly, dopamine gene-by-urbanicity interactions. For COMT, three independent human samples were recruited (total n = 487). We also studied 253 subjects genotyped for DRD1 and DRD2. 3T fMRI activation during the N-back WM task was the dependent variable, while childhood urbanicity, dopamine genotype, and urbanicity-dopamine interactions were independent variables. Main effects of dopamine genes and of urbanicity were found. Individuals raised in an urban environment showed altered prefrontal activation relative to those raised in rural or town settings. For each gene, dopamine genotype-by-urbanicity interactions were shown in prefrontal cortex-COMT replicated twice in two independent samples. An urban childhood upbringing altered prefrontal function and interacted with each gene to alter genotype-phenotype relationships. Gene-environment interactions between multiple dopamine genes and urban upbringing suggest that neural effects of developmental environmental exposure could mediate, at least partially, increased risk for psychiatric illness in urban environments via dopamine genes expressed into adulthood.

Use of cardiopulmonary exercise testing to assess early ventilatory changes related to occupational particulate matter

PubMed Central

Chao, T.P.; Sperandio, E.F.; Ostolin, T.L.V.P.; Almeida, V.R.; Romiti, M.; Gagliardi, A.R.T.; Arantes, R.L.; Dourado, V.Z.

2018-01-01

Spirometry has been used as the main strategy for assessing ventilatory changes related to occupational exposure to particulate matter (OEPM). However, in some cases, as one of its limitations, it may not be sensitive enough to show abnormalities before extensive damage, as seen in restrictive lung diseases. Therefore, we hypothesized that cardiopulmonary exercise testing (CPET) may be better than spirometry to detect early ventilatory impairment caused by OEPM. We selected 135 male workers with at least one year of exposure. After collection of self-reported socioeconomic status, educational level, and cardiovascular risk data, participants underwent spirometry, CPET, body composition assessment (bioelectrical impedance), and triaxial accelerometry (for level of physical activity in daily life). CPET was performed using a ramp protocol on a treadmill. Metabolic, cardiovascular, ventilatory, and submaximal relationships were measured. We compared 52 exposed to 83 non-exposed workers. Multiple linear regressions were developed using spirometry and CPET variables as outcomes and OEPM as the main predictor, and adjusted by the main covariates. Our results showed that OEPM was associated with significant reductions in peak minute ventilation, peak tidal volume, and breathing reserve index. Exposed participants presented shallower slope of ΔVT/ΔlnV̇E (breathing pattern), i.e., increased tachypneic breathing pattern. The OEPM explained 7.4% of the ΔVT/ΔlnV̇E variability. We found no significant influence of spirometric indices after multiple linear regressions. We conclude that CPET might be a more sensitive feature of assessing early pulmonary impairment related to OEPM. Our cross-sectional results suggested that CPET is a promising tool for the screening of asymptomatic male workers. PMID:29590255

Long-Term Neurotoxic Effects of Early Life Exposure to Tetrachloroethylene-contaminated Drinking Water

PubMed Central

Aschengrau, Ann; Janulewicz, Patricia A.; White, Roberta F.; Vieira, Veronica M.; Gallagher, Lisa G.; Getz, Kelly D.; Webster, Thomas F.; Ozonoff, David M.

2016-01-01

Background Tetrachloroethene (PCE) is a common environmental and occupational contaminant and an acknowledged neurotoxicant. From 1968 through 1983 widespread contamination of public drinking water supplies with PCE occurred in the Cape Cod region of Massachusetts. The source of the contamination was a vinyl liner applied to the inner surface of water distribution pipes. Objectives A retrospective cohort study (“the Cape Cod Health Study”) was undertaken to examine possible health consequences of early life exposure to PCE-contaminated drinking water. This review describes the study methods and findings regarding the impact of prenatal and childhood exposure on neurological outcomes during early adulthood, including vision, neuropsychological functioning, brain structure, risky behaviors, and mental illness. The review also describes the strengths and challenges of conducting population-based epidemiological research in this unique setting. Methods Subjects were identified by cross-matching birth certificate and water system data. Information on health outcomes and confounding variables was collected from self-administered surveys (N= 1,689), neuropsychological tests (N=63), vision exam (N=63), and magnetic resonance imaging (N=42). Early life exposure to PCE was estimated using a leaching and transport model. The data analysis compared the occurrence of each health outcome among subjects with prenatal and early childhood PCE exposure to unexposed subjects while considering the impact of confounding variables. Results The study found evidence that early life exposure to PCE-contaminated drinking water has long-term neurotoxic effects. The strongest associations were seen with illicit drug use, bipolar disorder, and post-traumatic stress disorder. Key strengths of the study were availability of historical data on affected water systems, a relatively high exposure prevalence and wide range of exposure levels, and little confounding. Challenges arose mainly from the historical nature of the exposure assessments. Conclusions The Cape Cod Health Study demonstrates how scientists can take advantage of unique “natural experiments” to learn about the health effects of environmental pollution. This body of work has improved our understanding of the long-term health effects of early life exposure to this common environmental contaminant and will help risk assessors and policy makers ensure that U.S. drinking water supplies are safe for vulnerable populations. PMID:27325074

Selected questions on biomechanical exposures for surveillance of upper-limb work-related musculoskeletal disorders

PubMed Central

Descatha, Alexis; Roquelaure, Yves; Evanoff, Bradley; Niedhammer, Isabelle; Chastang, Jean François; Mariot, Camille; Ha, Catherine; Imbernon, Ellen; Goldberg, Marcel; Leclerc, Annette

2007-01-01

Objective Questionnaires for assessment of biomechanical exposure are frequently used in surveillance programs, though few studies have evaluated which key questions are needed. We sought to reduce the number of variables on a surveillance questionnaire by identifying which variables best summarized biomechanical exposure in a survey of the French working population. Methods We used data from the 2002–2003 French experimental network of Upper-limb work-related musculoskeletal disorders (UWMSD), performed on 2685 subjects in which 37 variables assessing biomechanical exposures were available (divided into four ordinal categories, according to the task frequency or duration). Principal Component Analysis (PCA) with orthogonal rotation was performed on these variables. Variables closely associated with factors issued from PCA were retained, except those highly correlated to another variable (rho>0.70). In order to study the relevance of the final list of variables, correlations between a score based on retained variables (PCA score) and the exposure score suggested by the SALTSA group were calculated. The associations between the PCA score and the prevalence of UWMSD were also studied. In a final step, we added back to the list a few variables not retained by PCA, because of their established recognition as risk factors. Results According to the results of the PCA, seven interpretable factors were identified: posture exposures, repetitiveness, handling of heavy loads, distal biomechanical exposures, computer use, forklift operator specific task, and recovery time. Twenty variables strongly correlated with the factors obtained from PCA were retained. The PCA score was strongly correlated both with the SALTSA score and with UWMSD prevalence (p<0.0001). In the final step, six variables were reintegrated. Conclusion Twenty-six variables out of 37 were efficiently selected according to their ability to summarize major biomechanical constraints in a working population, with an approach combining statistical analyses and existing knowledge. PMID:17476519

Estimators for longitudinal latent exposure models: examining measurement model assumptions.

PubMed

Sánchez, Brisa N; Kim, Sehee; Sammel, Mary D

2017-06-15

Latent variable (LV) models are increasingly being used in environmental epidemiology as a way to summarize multiple environmental exposures and thus minimize statistical concerns that arise in multiple regression. LV models may be especially useful when multivariate exposures are collected repeatedly over time. LV models can accommodate a variety of assumptions but, at the same time, present the user with many choices for model specification particularly in the case of exposure data collected repeatedly over time. For instance, the user could assume conditional independence of observed exposure biomarkers given the latent exposure and, in the case of longitudinal latent exposure variables, time invariance of the measurement model. Choosing which assumptions to relax is not always straightforward. We were motivated by a study of prenatal lead exposure and mental development, where assumptions of the measurement model for the time-changing longitudinal exposure have appreciable impact on (maximum-likelihood) inferences about the health effects of lead exposure. Although we were not particularly interested in characterizing the change of the LV itself, imposing a longitudinal LV structure on the repeated multivariate exposure measures could result in high efficiency gains for the exposure-disease association. We examine the biases of maximum likelihood estimators when assumptions about the measurement model for the longitudinal latent exposure variable are violated. We adapt existing instrumental variable estimators to the case of longitudinal exposures and propose them as an alternative to estimate the health effects of a time-changing latent predictor. We show that instrumental variable estimators remain unbiased for a wide range of data generating models and have advantages in terms of mean squared error. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Occupational exposure in the removal and disposal of asbestos-containing materials in Italy.

PubMed

Scarselli, Alberto; Corfiati, Marisa; Di Marzio, Davide

2016-07-01

A great variety of asbestos-containing materials are present in both residential and work settings because of the widespread use made in the past, and many occupational activities still entail the risk of asbestos exposure in Italy, more than 2 decades after the total national ban, mainly those involved in the removal and disposal of asbestos. The aim of the study was to evaluate the level and extent of asbestos exposure in Italy between the years 1996-2013 in the sector of asbestos abatement. Data were collected from firm registries of asbestos-exposed workers and descriptive statistics were calculated for exposure-related variables. Overall, 15,860 measurements of asbestos exposure were selected from the national database of registries, mostly referring to the construction sector (N = 11,353). Despite the mean exposure levels are low, the air concentration of asbestos fibers measured during these activities may overcome the action level established by the Italian legislation and, in a limited number of cases, can exceed even the occupational limit value. Among occupations at higher risk, there are also garbage collectors and insulation workers. Starting from the analysis of the Italian database of occupational exposure registries, this study outlines the current levels of asbestos exposure in abatement-related sectors, discussing their possible implications for public health policies and surveillance programs.

Temporal Variability of Daily Personal Magnetic Field Exposure Metrics in Pregnant Women

PubMed Central

Lewis, Ryan C.; Evenson, Kelly R.; Savitz, David A.; Meeker, John D.

2015-01-01

Recent epidemiology studies of power-frequency magnetic fields and reproductive health have characterized exposures using data collected from personal exposure monitors over a single day, possibly resulting in exposure misclassification due to temporal variability in daily personal magnetic field exposure metrics, but relevant data in adults are limited. We assessed the temporal variability of daily central tendency (time-weighted average, median) and peak (upper percentiles, maximum) personal magnetic field exposure metrics over seven consecutive days in 100 pregnant women. When exposure was modeled as a continuous variable, central tendency metrics had substantial reliability, whereas peak metrics had fair (maximum) to moderate (upper percentiles) reliability. The predictive ability of a single day metric to accurately classify participants into exposure categories based on a weeklong metric depended on the selected exposure threshold, with sensitivity decreasing with increasing exposure threshold. Consistent with the continuous measures analysis, sensitivity was higher for central tendency metrics than for peak metrics. If there is interest in peak metrics, more than one day of measurement is needed over the window of disease susceptibility to minimize measurement error, but one day may be sufficient for central tendency metrics. PMID:24691007

Network Mendelian randomization: using genetic variants as instrumental variables to investigate mediation in causal pathways

PubMed Central

Burgess, Stephen; Daniel, Rhian M; Butterworth, Adam S; Thompson, Simon G

2015-01-01

Background: Mendelian randomization uses genetic variants, assumed to be instrumental variables for a particular exposure, to estimate the causal effect of that exposure on an outcome. If the instrumental variable criteria are satisfied, the resulting estimator is consistent even in the presence of unmeasured confounding and reverse causation. Methods: We extend the Mendelian randomization paradigm to investigate more complex networks of relationships between variables, in particular where some of the effect of an exposure on the outcome may operate through an intermediate variable (a mediator). If instrumental variables for the exposure and mediator are available, direct and indirect effects of the exposure on the outcome can be estimated, for example using either a regression-based method or structural equation models. The direction of effect between the exposure and a possible mediator can also be assessed. Methods are illustrated in an applied example considering causal relationships between body mass index, C-reactive protein and uric acid. Results: These estimators are consistent in the presence of unmeasured confounding if, in addition to the instrumental variable assumptions, the effects of both the exposure on the mediator and the mediator on the outcome are homogeneous across individuals and linear without interactions. Nevertheless, a simulation study demonstrates that even considerable heterogeneity in these effects does not lead to bias in the estimates. Conclusions: These methods can be used to estimate direct and indirect causal effects in a mediation setting, and have potential for the investigation of more complex networks between multiple interrelated exposures and disease outcomes. PMID:25150977

Childhood adverse life events and parental psychopathology as risk factors for bipolar disorder.

PubMed

Bergink, V; Larsen, J T; Hillegers, M H J; Dahl, S K; Stevens, H; Mortensen, P B; Petersen, L; Munk-Olsen, T

2016-10-25

Childhood adverse events are risk factors for later bipolar disorder. We quantified the risks for a later diagnosis of bipolar disorder after exposure to adverse life events in children with and without parental psychopathology. This register-based population cohort study included all persons born in Denmark from 1980 to 1998 (980 554 persons). Adversities before age 15 years were: familial disruption; parental somatic illness; any parental psychopathology; parental labour market exclusion; parental imprisonment; placement in out-of-home care; and parental natural and unnatural death. We calculated risk estimates of each of these eight life events as single exposure and risk estimates for exposure to multiple life events. Main outcome variable was a diagnosis of bipolar disorder after the age of 15 years, analysed with Cox proportional hazard regression. Single exposure to most of the investigated adversities were associated with increased risk for bipolar disorder, exceptions were parental somatic illness and parental natural death. By far the strongest risk factor for bipolar disorder in our study was any mental disorder in the parent (hazard ratio 3.53; 95% confidence interval 2.73-4.53) and the additional effects of life events on bipolar risk were limited. An effect of early adverse life events on bipolar risk later in life was mainly observed in children without parental psychopathology. Our findings do not exclude early-life events as possible risk factors, but challenge the concept of adversities as important independent determinants of bipolar disorder in genetically vulnerable individuals.

Sorafenib metabolism, transport, and enterohepatic recycling: physiologically based modeling and simulation in mice.

PubMed

Edginton, Andrea N; Zimmerman, Eric I; Vasilyeva, Aksana; Baker, Sharyn D; Panetta, John C

2016-05-01

This study used uncertainty and sensitivity analysis to evaluate a physiologically based pharmacokinetic (PBPK) model of the complex mechanisms of sorafenib and its two main metabolites, sorafenib glucuronide and sorafenib N-oxide in mice. A PBPK model for sorafenib and its two main metabolites was developed to explain disposition in mice. It included relevant influx (Oatp) and efflux (Abcc2 and Abcc3) transporters, hepatic metabolic enzymes (CYP3A4 and UGT1A9), and intestinal β-glucuronidase. Parameterization of drug-specific processes was based on in vitro, ex vivo, and in silico data along with plasma and liver pharmacokinetic data from single and multiple transporter knockout mice. Uncertainty analysis demonstrated that the model structure and parameter values could explain the observed variability in the pharmacokinetic data. Global sensitivity analysis demonstrated the global effects of metabolizing enzymes on sorafenib and metabolite disposition and the local effects of transporters on their respective substrate exposures. In addition, through hypothesis testing, the model supported that the influx transporter Oatp is a weak substrate for sorafenib and a strong substrate for sorafenib glucuronide and that the efflux transporter Abcc2 is not the only transporter affected in the Abcc2 knockout mouse. Translation of the mouse model to humans for the purpose of explaining exceptionally high human pharmacokinetic variability and its relationship with exposure-dependent dose-limiting toxicities will require delineation of the importance of these processes on disposition.

Can aircraft noise less than or equal 115 to dBA adversely affect reproductive outcome in USAF women?

NASA Astrophysics Data System (ADS)

Brubaker, P. A.

1985-06-01

It has been suggested, mainly through animal studies, that exposure to high noise levels may be associated with lower birth weight, reduced gestational length and other adverse reproductive outcomes. Few studies have been done on humans to show this association. The Air Force employs pregnant women in areas where there is a high potential for exposure to high noise levels. This study proposes a method to determine if there is an association between high frequency noise levels or = 115 dBA and adverse reproductive outcomes through a review of records and self-administered questionnaires in a case-comparison design. Prevelance rates will be calculated and a multiple logistic regression analysis computed for the independent variables that can affect reproduction.

Test of the stress sensitization model in adolescents following the pipeline explosion.

PubMed

Shao, Di; Gao, Qing-Ling; Li, Jie; Xue, Jiao-Mei; Guo, Wei; Long, Zhou-Ting; Cao, Feng-Lin

2015-10-01

The stress sensitization model states that early traumatic experiences increase vulnerability to the adverse effects of subsequent stressful life events. This study examined the effect of stress sensitization on development of posttraumatic stress disorder (PTSD) symptoms in Chinese adolescents who experienced the pipeline explosion. A total of 670 participants completed self-administered questionnaires on demographic characteristics and degree of explosion exposure, the Childhood Trauma Questionnaire (CTQ), and the Posttraumatic Stress Disorder Checklist-Civilian Version (PCL-C). Associations among the variables were explored using MANOVA, and main effects and interactions were analyzed. Overall MANOVA tests with the PCL-C indicated significant differences for gender (F=6.86, p=.000), emotional abuse (F=6.79, p=.000), and explosion exposure (F=22.40, p=.000). There were significant interactions between emotional abuse and explosion exposure (F=3.98, p=.008) and gender and explosion exposure (F=2.93, p=.033). Being female, childhood emotional abuse, and a high explosion exposure were associated with high PTSD symptom levels. Childhood emotional abuse moderated the effect of explosion exposure on PTSD symptoms. Thus, stress sensitization influenced the development of PTSD symptoms in Chinese adolescents who experienced the pipeline explosion as predicted by the model. Copyright © 2015 Elsevier Inc. All rights reserved.

Violence Exposure and Psychopathology in Latino Youth: The Moderating Role of Active and Avoidant Coping.

PubMed

Gudiño, Omar G; Stiles, Allison A; Diaz, Kathleen I

2018-06-01

Despite high rates of exposure to community violence among Latino youth in urban communities, there is considerable variability in individual outcomes. This study examined (a) associations between coping and indices of Latino culture, (b) main effects of active/avoidant coping on psychopathology, and (c) whether coping moderates the impact of violence exposure on mental health in Latino youth. Participants included 168 Latino youth (56% female; ages 11-14) that took part in a short-term longitudinal study. Results indicate that youth acculturation was positively associated with active coping, but enculturation level and immigrant status were not associated with coping. Structural equation models suggested that active coping was negatively associated with internalizing problems (p = .046) while avoidant coping was positively associated with internalizing problems (p = .013) and posttraumatic stress symptoms (p = .024). Moderation analyses revealed that violence exposure was more strongly associated with internalizing problems as reliance on avoidance coping increased. However, at high levels of violence exposure, a greater reliance on active coping was related to increased posttraumatic stress problems. Findings suggest that consideration of the specific stressor, level of stress exposure, and mental health problem-type may be crucial in determining the effectiveness of a coping strategy. Implications for future research and intervention are discussed.

Determinants of dermal exposure among Nicaraguan subsistence farmers during pesticide applications with backpack sprayers.

PubMed

Blanco, Luis E; Aragón, Aurora; Lundberg, Ingvar; Lidén, Carola; Wesseling, Catharina; Nise, Gun

2005-01-01

Identification of pesticide exposure determinants has become an issue in explaining exposure variability and improving control measures. Most studies have been conducted in industrialized countries. The aim of this study was to identify relevant dermal exposure determinants among Nicaraguan subsistence farmers. Field data on possible determinants were collected during 32 pesticide applications through observation and supplementary videorecording. A multistep reduction strategy brought down the 110 potential exposure determinants to 27 variables, which were grouped as worksite, spray equipment, working practices, clothing or hygiene practices related. Dermal exposure was quantified with a modification of Fenske's visual scoring method. Multivariate linear regression modeling within groups and across groups was performed. In the within-group analyses, work practices, spray equipment and worksite related determinants explained 52, 33 and 25% of the exposure variability, respectively. Clothing and hygiene practices were weaker determinants and did not always reduce the exposure. The final model included determinants from all groups except hygiene practices and explained 69% of the exposure variability. A less restricted model increased the explained variability to 75%. Several novel determinants were identified, including spraying on a muddy terrain, dew on plants, sealing the tank lid with a cloth and wiping sweat from the face. This study showed that a combination of observation and visual scoring techniques can provide valuable information on determinants of pesticide exposure and affected body parts under developing country conditions. The results could be used to develop job-specific questionnaires and to design training and preventive programs.

Optimizing Radiometric Fidelity to Enhance Aerial Image Change Detection Utilizing Digital Single Lens Reflex (DSLR) Cameras

NASA Astrophysics Data System (ADS)

Kerr, Andrew D.

Determining optimal imaging settings and best practices related to the capture of aerial imagery using consumer-grade digital single lens reflex (DSLR) cameras, should enable remote sensing scientists to generate consistent, high quality, and low cost image data sets. Radiometric optimization, image fidelity, image capture consistency and repeatability were evaluated in the context of detailed image-based change detection. The impetus for this research is in part, a dearth of relevant, contemporary literature, on the utilization of consumer grade DSLR cameras for remote sensing, and the best practices associated with their use. The main radiometric control settings on a DSLR camera, EV (Exposure Value), WB (White Balance), light metering, ISO, and aperture (f-stop), are variables that were altered and controlled over the course of several image capture missions. These variables were compared for their effects on dynamic range, intra-frame brightness variation, visual acuity, temporal consistency, and the detectability of simulated cracks placed in the images. This testing was conducted from a terrestrial, rather than an airborne collection platform, due to the large number of images per collection, and the desire to minimize inter-image misregistration. The results point to a range of slightly underexposed image exposure values as preferable for change detection and noise minimization fidelity. The makeup of the scene, the sensor, and aerial platform, influence the selection of the aperture and shutter speed which along with other variables, allow for estimation of the apparent image motion (AIM) motion blur in the resulting images. The importance of the image edges in the image application, will in part dictate the lowest usable f-stop, and allow the user to select a more optimal shutter speed and ISO. The single most important camera capture variable is exposure bias (EV), with a full dynamic range, wide distribution of DN values, and high visual contrast and acuity occurring around -0.7 to -0.3EV exposure bias. The ideal values for sensor gain, was found to be ISO 100, with ISO 200 a less desirable. This study offers researchers a better understanding of the effects of camera capture settings on RSI pairs and their influence on image-based change detection.

Predictors of Daily Mobility of Adults in Peri-Urban South India.

PubMed

Sanchez, Margaux; Ambros, Albert; Salmon, Maëlle; Bhogadi, Santhi; Wilson, Robin T; Kinra, Sanjay; Marshall, Julian D; Tonne, Cathryn

2017-07-14

Daily mobility, an important aspect of environmental exposures and health behavior, has mainly been investigated in high-income countries. We aimed to identify the main dimensions of mobility and investigate their individual, contextual, and external predictors among men and women living in a peri-urban area of South India. We used 192 global positioning system (GPS)-recorded mobility tracks from 47 participants (24 women, 23 men) from the Cardiovascular Health effects of Air pollution in Telangana, India (CHAI) project (mean: 4.1 days/person). The mean age was 44 (standard deviation: 14) years. Half of the population was illiterate and 55% was in unskilled manual employment, mostly agriculture-related. Sex was the largest determinant of mobility. During daytime, time spent at home averaged 13.4 (3.7) h for women and 9.4 (4.2) h for men. Women's activity spaces were smaller and more circular than men's. A principal component analysis identified three main mobility dimensions related to the size of the activity space, the mobility in/around the residence, and mobility inside the village, explaining 86% (women) and 61% (men) of the total variability in mobility. Age, socioeconomic status, and urbanicity were associated with all three dimensions. Our results have multiple potential applications for improved assessment of environmental exposures and their effects on health.

Predictors of Daily Mobility of Adults in Peri-Urban South India

PubMed Central

Kinra, Sanjay; Marshall, Julian D.; Tonne, Cathryn

2017-01-01

Daily mobility, an important aspect of environmental exposures and health behavior, has mainly been investigated in high-income countries. We aimed to identify the main dimensions of mobility and investigate their individual, contextual, and external predictors among men and women living in a peri-urban area of South India. We used 192 global positioning system (GPS)-recorded mobility tracks from 47 participants (24 women, 23 men) from the Cardiovascular Health effects of Air pollution in Telangana, India (CHAI) project (mean: 4.1 days/person). The mean age was 44 (standard deviation: 14) years. Half of the population was illiterate and 55% was in unskilled manual employment, mostly agriculture-related. Sex was the largest determinant of mobility. During daytime, time spent at home averaged 13.4 (3.7) h for women and 9.4 (4.2) h for men. Women’s activity spaces were smaller and more circular than men’s. A principal component analysis identified three main mobility dimensions related to the size of the activity space, the mobility in/around the residence, and mobility inside the village, explaining 86% (women) and 61% (men) of the total variability in mobility. Age, socioeconomic status, and urbanicity were associated with all three dimensions. Our results have multiple potential applications for improved assessment of environmental exposures and their effects on health. PMID:28708095

Early hyperreactive malarial splenomegaly and risk factors for evolution into the full-blown syndrome: a single-centre, retrospective, longitudinal study.

PubMed

Bisoffi, Zeno; Leoni, Stefania; Buonfrate, Dora; Lodesani, Claudia; Eseme, Franklin Esoka; Monteiro, Geraldo Badona; Marocco, Stefania; Guerriero, Massimo

2015-12-02

The hyperreactive malarial splenomegaly (HMS) represents a chronic, potentially fatal complication of malaria. Case definition includes: gross splenomegaly, high level of anti-malarial antibody and IgM, response to long-term anti-malarial prophylaxis. In this study, a large series of patients not fully meeting the case definition was tentatively classified as early hyperreactive malarial splenomegaly (e-HMS). The main research questions was: does "e-HMS" tend to evolve to the full-blown syndrome? And if so, what are the main factors influencing this evolution? Retrospective, longitudinal study. The patient database was searched to retrieve all potentially eligible patients. e-HMS was defined by splenomegaly of any size (with or without raised IgM), high anti-malarial antibody titre and exclusion of other causes of splenomegaly. The clinical outcome at following visits was analysed in relation to re-exposure to malaria, and to treatment (only part of the patients with e-HMS were treated with a single anti-malarial treatment and advised to follow an effective anti-malarial prophylaxis, if re-exposed). The association of the outcome with the main independent variables was first assessed with univariate analysis. A stepwise logistic regression model was then performed to study the association of the outcome with the main independent variables. One hundred and twenty-six subjects with e-HMS were retrieved. Eighty-one had at least one follow-up visit. Of 46 re-exposed to malaria for a variable period, 21 (46 %) had progressed, including 10/46 (22 %) evolving to full-blown HMS, while of 29 patients not re-exposed, 24 (93 %) had improved or cured and five (7 %) progressed (p < 0.001). At logistic regression re-exposure was confirmed as a major risk factor of progression (OR 9.458, CI 1.767-50.616) while treatment at initial visit was protective (OR 0.187, CI 0.054-0.650). e-HMS should be regarded as a clinical condition predisposing to HMS. Although the case definition may include false positives, e-HMS should be treated just as the full-blown syndrome. A single anti-malarial treatment is probably adequate, followed by effective prophylaxis for patients exposed again to malaria transmission.

[Occupational exposure investigation and protective measures in a tertiary infectious disease hospital].

PubMed

Ding, H M; Zhou, X P; Huang, J Z

2018-02-20

Objective: To investigate the cause of occupational exposure among 136 nurses in a tertiary infectious disease hospital, and puts forward the prevention strategy. Methods: A total of 136 nurses exposed to occupational exposure between 2014 and 2016 were included in the study. Analysis was conducted from the years of work of nurses, exposure routes, and the pathogens. Results: The nurses suffer from the highest risk of occupational exposures (73.91%) .Nurses working for less than 5 years and interns are most likely to suffer occupational exposure (45.59% and 35.29% respectively) . Occupational exposure was mainly caused by needle injuries, in which infusion was the main route of occupational exposure (36.76%) . The improper treatment of needle pulling after infusion is the main link of needle puncture (36.76%) . Occupational exposure pathogens were mainly HBV (63.24%) . Conclusion: Nursing staff is the high-risk group of occupational exposure. Irregular operation, lack of awareness of protection, improper disposal after the needle withdrawal and poor safety assessment of the operating environment are the main causes of occupational exposure. It is suggested to strengthen the training of occupational safety and protection, enhance clinical nurses occupational safety protection consciousness, standardize medical operation, so as to prevent the occurrence of occupational exposure.

Transmission of Bacterial Zoonotic Pathogens between Pets and Humans: The Role of Pet Food.

PubMed

Lambertini, Elisabetta; Buchanan, Robert L; Narrod, Clare; Pradhan, Abani K

2016-01-01

Recent Salmonella outbreaks associated with dry pet food and treats raised the level of concern for these products as vehicle of pathogen exposure for both pets and their owners. The need to characterize the microbiological and risk profiles of this class of products is currently not supported by sufficient specific data. This systematic review summarizes existing data on the main variables needed to support an ingredients-to-consumer quantitative risk model to (1) describe the microbial ecology of bacterial pathogens in the dry pet food production chain, (2) estimate pet exposure to pathogens through dry food consumption, and (3) assess human exposure and illness incidence due to contact with pet food and pets in the household. Risk models populated with the data here summarized will provide a tool to quantitatively address the emerging public health concerns associated with pet food and the effectiveness of mitigation measures. Results of such models can provide a basis for improvements in production processes, risk communication to consumers, and regulatory action.

Land Use Regression Modeling of Outdoor Noise Exposure in Informal Settlements in Western Cape, South Africa

PubMed Central

Sieber, Chloé; Ragettli, Martina S.; Toyib, Olaniyan; Baatjies, Roslyn; Saucy, Apolline; Probst-Hensch, Nicole; Dalvie, Mohamed Aqiel; Röösli, Martin

2017-01-01

In low- and middle-income countries, noise exposure and its negative health effects have been little explored. The present study aimed to assess the noise exposure situation in adults living in informal settings in the Western Cape Province, South Africa. We conducted continuous one-week outdoor noise measurements at 134 homes in four different areas. These data were used to develop a land use regression (LUR) model to predict A-weighted day-evening-night equivalent sound levels (Lden) from geographic information system (GIS) variables. Mean noise exposure during day (6:00–18:00) was 60.0 A-weighted decibels (dB(A)) (interquartile range 56.9–62.9 dB(A)), during night (22:00–6:00) 52.9 dB(A) (49.3–55.8 dB(A)) and average Lden was 63.0 dB(A) (60.1–66.5 dB(A)). Main predictors of the LUR model were related to road traffic and household density. Model performance was low (adjusted R2 = 0.130) suggesting that other influences than those represented in the geographic predictors are relevant for noise exposure. This is one of the few studies on the noise exposure situation in low- and middle-income countries. It demonstrates that noise exposure levels are high in these settings. PMID:29053590

Relation between lung function, exercise capacity, and exposure to asbestos cement.

PubMed Central

Wollmer, P; Eriksson, L; Jonson, B; Jakobsson, K; Albin, M; Skerfving, S; Welinder, H

1987-01-01

A group of 137 male workers with known exposure (mean 20 fibre years per millilitre) to asbestos cement who had symptoms or signs of pulmonary disease was studied together with a reference group of 49 healthy industrial workers with no exposure to asbestos. Lung function measurements were made at rest and during exercise. Evidence of lung fibrosis was found as well as of obstructive airways disease in the exposed group compared with the reference group. Asbestos cement exposure was related to variables reflecting lung fibrosis but not to variables reflecting airflow obstruction. Smoking was related to variables reflecting obstructive lung disease. Exercise capacity was reduced in the exposed workers and was related to smoking and to lung function variables, reflecting obstructive airways disease. There was no significant correlation between exercise capacity and exposure to asbestos cement. PMID:3651353

The effects of the Omagh bomb on adolescent mental health: a school-based study.

PubMed

Duffy, Michael; McDermott, Maura; Percy, Andrew; Ehlers, Anke; Clark, David M; Fitzgerald, Michael; Moriarty, John

2015-02-06

The main objective of this study was to assess psychiatric morbidity among adolescents following the Omagh car bombing in Northern Ireland in 1998. Data was collected within schools from adolescents aged between 14 and 18 years via a self-completion booklet comprised of established predictors of PTSD; type of exposure, initial emotional response, long-term adverse physical problems, predictors derived from Ehlers and Clark's (2000) cognitive model, a PTSD symptoms measure (PDS) and the General Health Questionnaire (GHQ). Those with more direct physical exposure were significantly more likely to meet caseness on the GHQ and the PDS. The combined pre and peri trauma risk factors highlighted in previous meta-analyses accounted for 20% of the variance in PDS scores but the amount of variance accounted for increased to 56% when the variables highlighted in Ehlers and Clark's cognitive model for PTSD were added. High rates of chronic PTSD were observed in adolescents exposed to the bombing. Whilst increased exposure was associated with increased psychiatric morbidity, the best predictors of PTSD were specific aspects of the trauma ('seeing someone you think is dying'), what you are thinking during the event ('think you are going to die') and the cognitive mechanisms employed after the trauma. As these variables are in principle amenable to treatment the results have implications for teams planning treatment interventions after future traumas.

Using an Ongoing Study of Terrestrial Plant Response to Ultraviolet Radiation in Project ALERT

NASA Technical Reports Server (NTRS)

Condon, Estelle; Skiles, J. W.; Seitz, Jeffery C.; Dantoni, Hector L.

1998-01-01

The ALERT (Augmented Learning Environment for Renewable Teaching) Project is a cooperative California-based program with two main partners: California State University (CSU) geoscience and education departments and two NASA Centers, the Jet Propulsion Laboratory (JPL) in Pasadena and the Ames Research Center (ARC) in Mountain View. This paper presents an example of how a NASA research effort can be used in the undergraduate classroom. A study, now in the fourth year, subjects test plants to exposures of varying solar ultraviolet (UV) radiation (280 - 340 nm); a full solar UV exposure, a solar UV exposure less about 14% of ambient UV flux, and a UV-blocked regime. This experiment is simple in that only modest amounts of expense are required yet it is elegant since only one variable, UV-flux is involved. The experiment lends itself to teaching several of the Earth Sciences because it uses information from botany, taxonomy, and ecology. Aspects of physics are inherent in the study since portions of the electromagnetic spectrum are studied. Further, since only one of many variables are manipulated, UV flux, the study demonstrates how the scientific method is used in formulating and testing hypotheses. Based on the ALERT experience this summer, this study will be implemented at a CSU campus with the expectation that it will serve as a pedagogical tool and where it will involve students in actual research.

Air pollution and childhood leukaemia: a nationwide case-control study in Italy.

PubMed

Badaloni, C; Ranucci, A; Cesaroni, G; Zanini, G; Vienneau, D; Al-Aidrous, F; De Hoogh, K; Magnani, C; Forastiere, F

2013-12-01

Leukaemia is the most common cancer in children, but its aetiology is still poorly understood. We tested the hypothesis that traffic-related air pollution is associated with paediatric leukaemia because of chronic exposure to several potential carcinogens. The Italian SETIL study (Study on the aetiology of lymphohematopoietic malignancies in children) was conducted in 14 Italian regions. All incident cases of leukaemia in children aged ≤10 years from these regions (period 1998-2001) were eligible for enrolment. Two controls per case, matched on birth date, gender and region of residence were randomly selected from the local population registries. Exposure assessment at birth residence included traffic indicators (distance to main roads and length of main roads within 100 m) and estimates of pollutants concentrations (particulate matter -PM2.5 and PM10- and gases -NO2 and O3-) from national dispersion model and land use regression models. The association between the exposure variables and leukaemia was assessed by logistic regression analyses. Participation rates were 91.4% among cases and 69.2% in controls; 620 cases (544 acute lymphocytic and 76 acute non-lymphocytic leukaemia) and 957 controls were included. Overall, when considering the residence at birth, 35.6% of cases and 42.4% of controls lived along busy roads, and the mean annual PM10 levels were 33.3 (SD=6.3) and 33.4 µg/m(3) (SD=6.5), respectively. No association was found, and all ORs, independent of the method of assessment and the exposure windows, were close to the null value. Using various exposure assessment strategies, air pollution appears not to affect the incidence of childhood leukaemia.

Affecting Factors of Secondhand Smoke Exposure in Korea: Focused on Different Exposure Locations.

PubMed

Sun, Li Yuan; Cheong, Hae Kwan; Lee, Eun Whan; Kang, Kyeong Jin; Park, Jae Hyun

2016-09-01

Exposure to secondhand smoke (SHS) not only can cause serious illness, but is also an economic and social burden. Contextual and individual factors of non-smoker exposure to SHS depend on location. However, studies focusing on this subject are lacking. In this study, we described and compared the factors related to SHS exposure according to location in Korea. Regarding individual factors related to SHS exposure, a common individual variable model and location-specific variable model was used to evaluate SHS exposure at home/work/public locations based on sex. In common individual variables, such as age, and smoking status showed different relationships with SHS exposure in different locations. Among home-related variables, housing type and family with a single father and unmarried children showed the strongest positive relationships with SHS exposure in both males and females. In the workplace, service and sales workers, blue-collar workers, and manual laborers showed the strongest positive association with SHS exposure in males and females. For multilevel analysis in public places, only SHS exposure in females was positively related with cancer screening rate. Exposure to SHS in public places showed a positive relationship with drinking rate and single-parent family in males and females. The problem of SHS embodies social policies and interactions between individuals and social contextual factors. Policy makers should consider the contextual factors of specific locations and regional and individual context, along with differences between males and females, to develop effective strategies for reducing SHS exposure.

Working conditions and occupational risk exposure in employees driving for work.

PubMed

Fort, Emmanuel; Ndagire, Sheba; Gadegbeku, Blandine; Hours, Martine; Charbotel, Barbara

2016-04-01

An analysis of the occupational constraints and exposures to which employees facing road risk at work are subject was performed, with comparison versus non-exposed employees. Objective was to improve knowledge of the characteristics of workers exposed to road risk in France and of the concomitant occupational constraints. The descriptive study was based on data from the 2010 SUMER survey (Medical Monitoring of Occupational Risk Exposure: Surveillance Médicale des Expositions aux Risques professionnels), which included data not only on road risk exposure at work but also on a range of socio-occupational factors and working conditions. The main variable of interest was "driving (car, truck, bus, coach, etc.) on public thoroughfares" for work (during the last week of work). This was a dichotomous "Yes/No" variable, distinguishing employees who drove for work; it also comprised 4-step weekly exposure duration: <2h, 2-10h, 10-20h and ≥20h. 75% of the employees with driving exposure were male. Certain socio-occupational categories were found significantly more frequently: professional drivers (INSEE occupations and socio-occupational categories (PCS) 64), skilled workers (PCS 61), intermediate professions and teaching, health, civil service (functionaries) and assimilated (PCS 46) and company executives (PCS 36). Employees with driving exposure more often worked in small businesses or establishments. Constraints in terms of schedule and work-time were more frequent in employees with driving exposure. Constraints in terms of work rhythm were more frequent in non-exposed employees, with the exception of external demands requiring immediate response. On the Karasek's Job Demand-Control Model, employees with driving exposure less often had low decision latitude. Prevalence of job-strain was also lower, as was prevalence of "iso-strain" (combination of job-strain and social isolation). Employees with driving exposure were less often concerned by hostile behavior and, when they did report such psychological violence (inspired on the Leymann questionnaire), it was significantly more frequently due to clients, users or patients. Employees with driving exposure at work showed several specificities. The present study, based on a representative nationwide survey of employees, confirmed the existence of differences in working conditions between employees with and without driving exposure at work. In employees with driving exposure, constraints in terms of work-time and rhythm increased with weekly exposure duration, as did tension at work and exposure to hostile behavior. Copyright © 2016 Elsevier Ltd. All rights reserved.

Kids'Cam: An Objective Methodology to Study the World in Which Children Live.

PubMed

Signal, Louise N; Smith, Moira B; Barr, Michelle; Stanley, James; Chambers, Tim J; Zhou, Jiang; Duane, Aaron; Jenkin, Gabrielle L S; Pearson, Amber L; Gurrin, Cathal; Smeaton, Alan F; Hoek, Janet; Ni Mhurchu, Cliona

2017-09-01

This paper reports on a new methodology to objectively study the world in which children live. The primary research study (Kids'Cam Food Marketing) illustrates the method; numerous ancillary studies include exploration of children's exposure to alcohol, smoking, "blue" space and gambling, and their use of "green" space, transport, and sun protection. One hundred sixty-eight randomly selected children (aged 11-13 years) recruited from 16 randomly selected schools in Wellington, New Zealand used wearable cameras and GPS units for 4 days, recording imagery every 7 seconds and longitude/latitude locations every 5 seconds. Data were collected from July 2014 to June 2015. Analysis commenced in 2015 and is ongoing. Bespoke software was used to manually code images for variables of interest including setting, marketing media, and product category to produce variables for statistical analysis. GPS data were extracted and cleaned in ArcGIS, version 10.3 for exposure spatial analysis. Approximately 1.4 million images and 2.2 million GPS coordinates were generated (most were usable) from many settings including the difficult to measure aspects of exposures in the home, at school, and during leisure time. The method is ethical, legal, and acceptable to children and the wider community. This methodology enabled objective analysis of the world in which children live. The main arm examined the frequency and nature of children's exposure to food and beverage marketing and provided data on difficult to measure settings. The methodology will likely generate robust evidence facilitating more effective policymaking to address numerous public health concerns. Copyright © 2017. Published by Elsevier Inc.

Mercury, lead and cadmium in human milk in relation to diet, lifestyle habits and sociodemographic variables in Madrid (Spain).

PubMed

García-Esquinas, Esther; Pérez-Gómez, Beatriz; Fernández, Mario Antonio; Pérez-Meixeira, Ana María; Gil, Elisa; de Paz, Concha; Iriso, Andrés; Sanz, Juan Carlos; Astray, Jenaro; Cisneros, Margot; de Santos, Amparo; Asensio, Angel; García-Sagredo, José Miguel; García, José Frutos; Vioque, Jesus; Pollán, Marina; López-Abente, Gonzalo; González, Maria José; Martínez, Mercedes; Bohigas, Pedro Arias; Pastor, Roberto; Aragonés, Nuria

2011-09-01

Although breastfeeding is the ideal way of nurturing infants, it can be a source of exposure to toxicants. This study reports the concentration of Hg, Pb and Cd in breast milk from a sample of women drawn from the general population of the Madrid Region, and explores the association between metal levels and socio-demographic factors, lifestyle habits, diet and environmental exposures, including tobacco smoke, exposure at home and occupational exposures. Breast milk was obtained from 100 women (20 mL) at around the third week postpartum. Pb, Cd and Hg levels were determined using Atomic Absorption Spectrometry. Metal levels were log-transformed due to non-normal distribution. Their association with the variables collected by questionnaire was assessed using linear regression models. Separate models were fitted for Hg, Pb and Cd, using univariate linear regression in a first step. Secondly, multivariate linear regression models were adjusted introducing potential confounders specific for each metal. Finally, a test for trend was performed in order to evaluate possible dose-response relationships between metal levels and changes in variables categories. Geometric mean Hg, Pb and Cd content in milk were 0.53 μg L(-1), 15.56 μg L(-1), and 1.31 μg L(-1), respectively. Decreases in Hg levels in older women and in those with a previous history of pregnancies and lactations suggested clearance of this metal over lifetime, though differences were not statistically significant, probably due to limited sample size. Lead concentrations increased with greater exposure to motor vehicle traffic and higher potato consumption. Increased Cd levels were associated with type of lactation and tended to increase with tobacco smoking. Surveillance for the presence of heavy metals in human milk is needed. Smoking and dietary habits are the main factors linked to heavy metal levels in breast milk. Our results reinforce the need to strengthen national food safety programs and to further promote avoidance of unhealthy behaviors such as smoking during pregnancy. Copyright © 2011 Elsevier Ltd. All rights reserved.

Psychosocial outcomes related to subjective threat from armed conflict events (STACE): Findings from the Israeli-Palestinian cross-cultural HBSC study.

PubMed

Harel-Fisch, Yossi; Radwan, Qasrowi; Walsh, Sophie D; Laufer, Avital; Amitai, Gabriel; Fogel-Grinvald, Haya; Abdeen, Ziad

2010-09-01

This study investigates the relationship between exposure to armed conflict and terror events, and an array of mental and behavioral outcomes within a large cross-cultural scientifically representative sample of 24,935 Palestinian (7,430 West Bank and 7,217 Gaza) and Israeli (5,255 Jewish and 6,033 Arab) 11-, 13-, and 15-year-old school children. The children of the Middle East have been subjected to exposure from armed conflict and terrorism repeatedly with no adequate research or interventions aimed at shielding them from the hazards of such exposure to their mental and social well-being. This paper studies the relationship between a newly developed scale (STACE) measuring levels of subjective perceptions of threat/fear due to exposure to armed conflict events and its predicting association with six psychosocial and behavioral outcomes covering (1) poor mental health, (2) positive well-being, and (3) risk behaviors. It also examines the role of parental support in "buffering" the effects of exposure to armed conflict events within the four target populations. Results showed that STACE has significant and strong effects on all six dependent variables representing (1) mental post trauma, (2) diminished well-being, and (3) elevated risk behaviors. STACE strongly affects all four populations with the greatest impact among the Jewish Israeli population and the least impact shown for the Arab Israeli youth. Parental support ("significant adult") has both a direct main effect on the outcomes of all six variables as well as a significant "buffering" effect on the impact of STACE on certain outcome variables (posttraumatic symptoms, life satisfaction, positive life perceptions, and tobacco use). Regardless of the type of armed conflict events, the perception of threat and fear that a child experiences has a universal significant negative impact on mental, social, and behavioral well-being. The importance of the existence of a supporting significant adult in exposed children's lives is also emphasized. The findings show major implications for the development of community-based interventions focusing on enhancing parental, and other adult support in the lives of children living in armed conflict regions of the world. Copyright © 2010 Elsevier Ltd. All rights reserved.

The role of CO2 variability and exposure time for biological impacts of ocean acidification

NASA Astrophysics Data System (ADS)

Shaw, Emily C.; Munday, Philip L.; McNeil, Ben I.

2013-09-01

impacts of ocean acidification have mostly been studied using future levels of CO2 without consideration of natural variability or how this modulates both duration and magnitude of CO2 exposure. Here we combine results from laboratory studies on coral reef fish with diurnal in situ CO2 data from a shallow coral reef, to demonstrate how natural variability alters exposure times for marine organisms under increasingly high-CO2 conditions. Large in situ CO2 variability already results in exposure of coral reef fish to short-term CO2 levels higher than laboratory-derived critical CO2 levels (~600 µatm). However, we suggest that the in situ exposure time is presently insufficient to induce negative effects observed in laboratory studies. Our results suggest that both exposure time and the magnitude of CO2 levels will be important in determining the response of organisms to future ocean acidification, where both will increase markedly with future increases in CO2.

Comparing the effects of entertainment media and tobacco marketing on youth smoking in Germany.

PubMed

Sargent, James D; Hanewinkel, Reiner

2009-05-01

To examine differential effects of smoking in films and tobacco advertising on adolescent smoking. We hypothesize that movie smoking will have greater effects on smoking initiation, whereas tobacco advertising receptivity will primarily affect experimentation. Longitudinal observational study of adolescents. School-based surveys conducted in Schleswig-Holstein, Germany. A total of 4384 adolescents age 11-15 years at baseline and re-surveyed 1 year later; ever smoking prevalence was 38% at time 1. The main outcome variable combined two items assessing life-time and current smoking (alpha = 0.87). Baseline never smokers were analyzed separately from those who had tried smoking (ever smokers). Exposure to smoking in 398 internationally distributed US movies was modeled as a continuous variable, with 0 corresponding to the 5th percentile and 1 to the 95th percentile of exposure. Tobacco marketing receptivity consisted of naming a brand for a favorite tobacco advertisement. Ordinal logistic regressions controlled for socio-demographics, other social influences, personality characteristics of the adolescent and parenting style. Whereas 34% of ever smokers were receptive to tobacco marketing at time 1, only 6% of never smokers were. Among time 1 never smokers, exposure to movie smoking was a significantly stronger predictor of higher time 2 smoking level [adjusted proportional odds ratio = 2.76, 95% confidence interval (1.84, 4.15)] than was tobacco marketing receptivity (1.53 [1.07, 2.20]). Among time 1 ever smokers, both tobacco marketing receptivity and exposure to movie smoking predicted higher levels of time 2 smoking [2.17 (1.78, 2.63) and 1.62 (1.18, 2.23), respectively], and the two estimates were not significantly different. In this longitudinal study, exposure to movie smoking was a stronger predictor of smoking initiation than tobacco marketing receptivity, which was more common among ever smokers. The results suggest that entertainment media smoking should be emphasized in programs aimed at preventing onset, and both exposures should be emphasized in programs aimed at experimental smokers.

Relationship of Religiousness and Religious Coping with Quality of Life among War Trauma Survivors.

PubMed

Fadilpašić, Senadin; Maleč, Daniel; Džubur-Kulenović, Alma

2017-09-01

Long-term posttraumatic outcomes such as quality of life are dependent on a series of factors from the very exposure to traumatic events and stress appraisals, personality traits, posttraumatic growth, symptoms of Posttraumatic stress disorder (PTSD) and different coping strategies to religiousness and religious coping styles. Except of exposure to traumatic events and related stress, all other variables may have indirect mediating effects on long-term posttraumatic outcomes. The main aim of this cross-sectional study is to explore relative independent contribution of these variables in the explanation of quality of life among war trauma survivors, with a special emphasis on the variables of religiousness and religious coping. The research was conducted on 353 subjects who experienced war related traumatic events during the war in Bosnia and Herzegovina (B&H). The data was collected through several self-report measuring instruments: Manchester Short Assessment of Quality of Life, Stressors Check List (SCL); Religiousness Scale, Social Support Resources Scale; Religious Problem-Solving Scale, Brief RCOPE, Posttraumatic Growth Inventory and Mississippi Scale for PTSD. According to the results of the study, experience of loss and frequent exposure to war trauma and high levels on the primary stress appraisals, self-directing coping style and PTSD-symptoms were associated with lower perceived quality of life among the subjects. High levels of extrinsic religious orientation, effect of religiousness on social behavior, positive religious coping and posttraumatic growth were associated with higher perceived quality of life among subjects. These variables showed significant independent contribution to the prediction of the values on quality of life. Results of the study have a scientific significance in understanding the importance and mediating role of religiousness and religious coping for quality of life perception as one of long-term posttraumatic outcomes. Effects of religiousness on social behavior and positive religious coping showed particularly significant contribution across all prediction models for the quality of life.

Sun Exposure, Vitamin D Receptor Polymorphisms FokI and BsmI and Risk of Multiple Primary Melanoma

PubMed Central

Mandelcorn-Monson, Rochelle; Marrett, Loraine; Kricker, Anne; Armstrong, Bruce K.; Orlow, Irene; Goumas, Chris; Paine, Susan; Rosso, Stefano; Thomas, Nancy; Millikan, Robert C.; Pole, Jason D.; Cotignola, Javier; Rosen, Cheryl; Kanetsky, Peter A.; Lee-Taylor, Julia; Begg, Colin B.; Berwick, Marianne

2011-01-01

Sunlight exposure increases risk of melanoma. Sunlight also potentiates cutaneous synthesis of vitamin D, which can inhibit melanoma cell growth and promote apoptosis. Vitamin D effects are mediated through the vitamin D receptor (VDR). We hypothesized that genetic variation in VDR affects the relationship of sun exposure to risk of a further melanoma in people who have already had one. We investigated the interaction between VDR polymorphisms and sun exposure in a population-based multinational study comparing 1138 patients with a multiple (second or subsequent) primary melanoma (cases) to 2151 patients with a first primary melanoma (controls); essentially a case-control study of melanoma in a population of melanoma survivors. Sun exposure was assessed using a questionnaire and interview, and was shown to be associated with multiple primary melanoma. VDR was genotyped at the FokI and BsmI loci and the main effects of variants at these loci and their interactions with sun exposure were analyzed. Only the BsmI variant was associated with multiple primary melanoma (OR = 1.27, 95% CI 0.99-1.62 for the homozygous variant genotype). Joint effects analyses showed highest ORs in the high exposure, homozygous variant BsmI genotype category for each sun exposure variable. Stratified analyses showed somewhat higher ORs for the homozygous BsmI variant genotype in people with high sun exposure than with low sun exposure. P values for interaction, however, were high. These results suggest that risk of multiple primary melanoma is increased in people who have the BsmI variant of VDR. PMID:21612999

Job Strain and Casual Blood Pressure Distribution: Looking beyond the Adjusted Mean and Taking Gender, Age, and Use of Antihypertensives into Account. Results from ELSA-Brasil

PubMed Central

Juvanhol, Leidjaira Lopes; Melo, Enirtes Caetano Prates; Carvalho, Marilia Sá; Chor, Dóra; Mill, José Geraldo; Griep, Rosane Härter

2017-01-01

Methodological issues are pointed to as the main sources of inconsistencies in studies about the association between job strain and blood pressure (BP)/hypertension. Our aim was to analyze the relationship between job strain and the whole BP distribution, as well as potential differences by gender, age, and use of antihypertensives. Additionally, we addressed issues relating to the operationalization of the exposure and outcome variables that influence the study of their inter-relations. We evaluated the baseline date of 12,038 participants enrolled in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) (2008–2010), a multicenter cohort study of 35–74-year-old civil servants. Job strain was assessed by the Demand-Control-Support Questionnaire. The distribution of casual BP by categories of job strain was compared by a combination of exploratory techniques. Participants were classified into three subgroups (normotensives, medicated hypertensives, and unmedicated hypertensives), and analyses were stratified by gender and age. The relationship between job strain and casual BP varied along the whole outcome distribution. Hypertensive participants had greater differences in casual BP by job strain category, especially medicated hypertensives. Differences in casual BP were also greater for systolic than for diastolic BP and for older participants. No differences were encountered by gender. The exclusion of participants susceptible to misclassification for the exposure and outcome variables increased the differences observed between the categories of low and high job strain. In conclusion, the relationship between job strain and casual BP varied along the whole outcome distribution and by use of antihypertensive drugs, age, and BP parameter evaluated. Misclassification for exposure and outcome variables should be considered in analyses of this topic. PMID:28441727

Seventy two-hour glucose monitoring profiles in mild gestational diabetes mellitus: differences from healthy pregnancies and influence of diet counseling.

PubMed

Carreiro, Marina Pimenta; Lauria, Márcio W; Naves, Gabriel Nino T; Miranda, Paulo Augusto C; Leite, Ricardo Barsaglini; Rajão, Kamilla Maria Araújo Brandão; de Aguiar, Regina Amélia Lopes Pessoa; Nogueira, Anelise Impeliziere; Ribeiro-Oliveira, Antônio

2016-09-01

To study glucose profiles of gestational diabetes (GDM) patients with 72 h of continuous glucose monitoring (CGM) either before (GDM1) or after (GDM2) dietary counseling, comparing them with nondiabetic (NDM) controls. We performed CGM on 22 GDM patients; 11 before and 11 after dietary counseling and compared them to 11 healthy controls. Several physiological and clinical characteristics of the glucose profiles were compared across the groups, including comparisons for pooled 24-h measures and hourly median values, summary measures representing glucose exposure (area under the median curves) and variability (amplitude, standard deviation, interquartile range), and time points related to meals. Most women (81.8%) in the GDM groups had fasting glucose <95mg/dL, suggesting mild GDM. Variability, glucose levels 1 and 2h after breakfast and dinner, peak values after dinner and glucose levels between breakfast and lunch, were all significantly higher in GDM1 than NDM (P<0.05 for all comparisons). The GDM2 results were similar to NDM in all aforementioned comparisons (P>0.05). Both GDM groups spent more time with glucose levels above 140mg/dL when compared with the NDM group. No differences among the groups were found for: pooled measurements and hourly comparisons, exposure, nocturnal, fasting, between lunch and dinner and before meals, as well as after lunch (P>0.05 for all). The main differences between the mild GDM1 group and healthy controls were related to glucose variability and excursions above 140mg/dL, while glucose exposure was similar. Glucose levels after breakfast and dinner also discerned the GDM1 group. Dietary counseling was able to keep glucose levels to those of healthy patients. © 2016 European Society of Endocrinology.

Decreased Radiation Exposure and Increased Efficacy in Extracorporeal Lithotripsy Using a New Ultrasound Stone Locking System.

PubMed

Abid, Nadia; Ravier, Emmanuel; Promeyrat, Xavier; Codas, Ricardo; Fehri, Hakim Fassi; Crouzet, Sebastien; Martin, Xavier

2015-11-01

To compare fluoroscopy duration, radiation dose, and efficacy of two ultrasound stone localization systems during extracorporeal shockwave lithotripsy (SWL) treatment. Monocentric prospective data were obtained from patients consecutively treated for renal stones using the Sonolith(®) i-sys (EDAP TMS) lithotripter, with fluoroscopy combined with ultrasound localization using an "outline" Automatic Ultrasound Positioning Support (AUPS) (group A), or the "free-line" Visio-Track (VT) (EDAP-TMS) hand-held three-dimensional ultrasound stone locking system (group B). Efficacy rate was defined as the within-groups proportion stone free or with partial stone fragmentation not needing additional procedures. Statistical analysis used Pearson chi-square tests for categoric variables, nonparametric Mann-Whitney tests for continuous variables, and linear regression for operator learning curve with VT. Continuous variables were reported as median (range) values. Patients in group A (n=73) and group B (n=81) were comparable in baseline characteristics (age, kidney stone size, others) and in SWL application (duration, number of shocks, energy [Joules]). During SWL, the median (range) duration (seconds) of radiation exposure was 159.5 (0-690) in group A and 3.5 (0-478) in group B (P<0.001) and irradiation dose (mGy.cm(2)), 10598 (0-54843) in group A and 163 (0-13926) in group B (P<0.001). Fluoroscopy time significantly decreased with operator experience using VT. The efficacy rate was 54.5% in group A and 79.5% in group B (P=0.001). VT significantly reduced fluoroscopy use during SWL and the duration and dose of patient exposure to ionizing radiation. Stone treatment efficacy was significantly greater with VT mainly because of a better real-time monitoring of the stone.

Non-precautionary aspects of toxicology

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

Grandjean, Philippe

2005-09-01

Empirical studies in toxicology aim at deciphering complex causal relationships, especially in regard to human disease etiologies. Several scientific traditions limit the usefulness of documentation from current toxicological research, in regard to decision-making based on the precautionary principle. Among non-precautionary aspects of toxicology are the focus on simplified model systems and the effects of single hazards, one by one. Thus, less attention is paid to sources of variability and uncertainty, including individual susceptibility, impacts of mixed and variable exposures, susceptible life-stages, and vulnerable communities. In emphasizing the need for confirmatory evidence, toxicology tends to penalize false positives more than falsemore » negatives. An important source of uncertainty is measurement error that results in misclassification, especially in regard to exposure assessment. Standard statistical analysis assumes that the exposure is measured without error, and imprecisions will usually result in an underestimation of the dose-effect relationship. In testing whether an effect could be considered a possible result of natural variability, a 5% limit for 'statistical significance' is usually applied, even though it may rule out many findings of causal associations, simply because the study was too small (and thus lacked statistical power) or because some imprecision or limited sensitivity of the parameters precluded a more definitive observation. These limitations may be aggravated when toxicology is influenced by vested interests. Because current toxicology overlooks the important goal of achieving a better characterization of uncertainties and their implications, research approaches should be revised and strengthened to counteract the innate ideological biases, thereby supporting our confidence in using toxicology as a main source of documentation and in using the precautionary principle as a decision procedure in the public policy arena.« less

Job Strain and Casual Blood Pressure Distribution: Looking beyond the Adjusted Mean and Taking Gender, Age, and Use of Antihypertensives into Account. Results from ELSA-Brasil.

PubMed

Juvanhol, Leidjaira Lopes; Melo, Enirtes Caetano Prates; Carvalho, Marilia Sá; Chor, Dóra; Mill, José Geraldo; Griep, Rosane Härter

2017-04-22

Methodological issues are pointed to as the main sources of inconsistencies in studies about the association between job strain and blood pressure (BP)/hypertension. Our aim was to analyze the relationship between job strain and the whole BP distribution, as well as potential differences by gender, age, and use of antihypertensives. Additionally, we addressed issues relating to the operationalization of the exposure and outcome variables that influence the study of their inter-relations. We evaluated the baseline date of 12,038 participants enrolled in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) (2008-2010), a multicenter cohort study of 35-74-year-old civil servants. Job strain was assessed by the Demand-Control-Support Questionnaire. The distribution of casual BP by categories of job strain was compared by a combination of exploratory techniques. Participants were classified into three subgroups (normotensives, medicated hypertensives, and unmedicated hypertensives), and analyses were stratified by gender and age. The relationship between job strain and casual BP varied along the whole outcome distribution. Hypertensive participants had greater differences in casual BP by job strain category, especially medicated hypertensives. Differences in casual BP were also greater for systolic than for diastolic BP and for older participants. No differences were encountered by gender. The exclusion of participants susceptible to misclassification for the exposure and outcome variables increased the differences observed between the categories of low and high job strain. In conclusion, the relationship between job strain and casual BP varied along the whole outcome distribution and by use of antihypertensive drugs, age, and BP parameter evaluated. Misclassification for exposure and outcome variables should be considered in analyses of this topic.

Including exposure variability in the life cycle impact assessment of indoor chemical emissions: the case of metal degreasing.

PubMed

Golsteijn, Laura; Huizer, Daan; Hauck, Mara; van Zelm, Rosalie; Huijbregts, Mark A J

2014-10-01

The present paper describes a method that accounts for variation in indoor chemical exposure settings and accompanying human toxicity in life cycle assessment (LCA). Metal degreasing with dichloromethane was used as a case study to show method in practice. We compared the human toxicity related to the degreasing of 1m(2) of metal surface in different exposure scenarios for industrial workers, professional users outside industrial settings, and home consumers. The fraction of the chemical emission that is taken in by exposed individuals (i.e. the intake fraction) was estimated on the basis of operational conditions (e.g. exposure duration), and protective measures (e.g. local exhaust ventilation). The introduction of a time-dependency and a correction for protective measures resulted in reductions in the intake fraction of up to 1.5 orders of magnitude, compared to application of existing, less advanced models. In every exposure scenario, the life cycle impacts for human toxicity were mainly caused by indoor exposure to metal degreaser (>60%). Emissions released outdoors contributed up to 22% of the life cycle impacts for human toxicity, and the production of metal degreaser contributed up to 19%. These findings illustrate that human toxicity from indoor chemical exposure should not be disregarded in LCA case studies. Particularly when protective measures are taken or in the case of a short duration (1h or less), we recommend the use of our exposure scenario-specific approach. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fuzzy intelligent quality monitoring model for X-ray image processing.

PubMed

Khalatbari, Azadeh; Jenab, Kouroush

2009-01-01

Today's imaging diagnosis needs to adapt modern techniques of quality engineering to maintain and improve its accuracy and reliability in health care system. One of the main factors that influences diagnostic accuracy of plain film X-ray on detecting pathology is the level of film exposure. If the level of film exposure is not adequate, a normal body structure may be interpretated as pathology and vice versa. This not only influences the patient management but also has an impact on health care cost and patient's quality of life. Therefore, providing an accurate and high quality image is the first step toward an excellent patient management in any health care system. In this paper, we study these techniques and also present a fuzzy intelligent quality monitoring model, which can be used to keep variables from degrading the image quality. The variables derived from chemical activity, cleaning procedures, maintenance, and monitoring may not be sensed, measured, or calculated precisely due to uncertain situations. Therefore, the gamma-level fuzzy Bayesian model for quality monitoring of an image processing is proposed. In order to apply the Bayesian concept, the fuzzy quality characteristics are assumed as fuzzy random variables. Using the fuzzy quality characteristics, the newly developed model calculates the degradation risk for image processing. A numerical example is also presented to demonstrate the application of the model.

Beyond the job exposure matrix (JEM): the task exposure matrix (TEM).

PubMed

Benke, G; Sim, M; Fritschi, L; Aldred, G

2000-09-01

The job exposure matrix (JEM) has been employed to assign cumulative exposure to workers in many epidemiological studies. In these studies, where quantitative data are available, all workers with the same job title and duration are usually assigned similar cumulative exposures, expressed in mgm(-3)xyears. However, if the job is composed of multiple tasks, each with its own specific exposure profile, then assigning all workers within a job the same mean exposure can lead to misclassification of exposure. This variability of exposure within job titles is one of the major weaknesses of JEMs. A method is presented for reducing the variability in the JEM methodology, which has been called the task exposure matrix (TEM). By summing the cumulative exposures of a worker over all the tasks worked within a job title, it is possible to address the variability of exposure within the job title, and reduce possible exposure misclassification. The construction of a TEM is outlined and its application in the context of a study in the primary aluminium industry is described. The TEM was found to assign significantly different cumulative exposures to the majority of workers in the study, compared with the JEM and the degree of difference in cumulative exposure between the JEM and the TEM varied greatly between contaminants.

Environmental exposure assessment in European birth cohorts: results from the ENRIECO project

PubMed Central

2013-01-01

Environmental exposures during pregnancy and early life may have adverse health effects. Single birth cohort studies often lack statistical power to tease out such effects reliably. To improve the use of existing data and to facilitate collaboration among these studies, an inventory of the environmental exposure and health data in these studies was made as part of the ENRIECO (Environmental Health Risks in European Birth Cohorts) project. The focus with regard to exposure was on outdoor air pollution, water contamination, allergens and biological organisms, metals, pesticides, smoking and second hand tobacco smoke (SHS), persistent organic pollutants (POPs), noise, radiation, and occupational exposures. The review lists methods and data on environmental exposures in 37 European birth cohort studies. Most data is currently available for smoking and SHS (N=37 cohorts), occupational exposures (N=33), outdoor air pollution, and allergens and microbial agents (N=27). Exposure modeling is increasingly used for long-term air pollution exposure assessment; biomonitoring is used for assessment of exposure to metals, POPs and other chemicals; and environmental monitoring for house dust mite exposure assessment. Collaborative analyses with data from several birth cohorts have already been performed successfully for outdoor air pollution, water contamination, allergens, biological contaminants, molds, POPs and SHS. Key success factors for collaborative analyses are common definitions of main exposure and health variables. Our review emphasizes that such common definitions need ideally be arrived at in the study design phase. However, careful comparison of methods used in existing studies also offers excellent opportunities for collaborative analyses. Investigators can use this review to evaluate the potential for future collaborative analyses with respect to data availability and methods used in the different cohorts and to identify potential partners for a specific research question. PMID:23343014

Deciphering the complex: methodological overview of statistical models to derive OMICS-based biomarkers.

PubMed

Chadeau-Hyam, Marc; Campanella, Gianluca; Jombart, Thibaut; Bottolo, Leonardo; Portengen, Lutzen; Vineis, Paolo; Liquet, Benoit; Vermeulen, Roel C H

2013-08-01

Recent technological advances in molecular biology have given rise to numerous large-scale datasets whose analysis imposes serious methodological challenges mainly relating to the size and complex structure of the data. Considerable experience in analyzing such data has been gained over the past decade, mainly in genetics, from the Genome-Wide Association Study era, and more recently in transcriptomics and metabolomics. Building upon the corresponding literature, we provide here a nontechnical overview of well-established methods used to analyze OMICS data within three main types of regression-based approaches: univariate models including multiple testing correction strategies, dimension reduction techniques, and variable selection models. Our methodological description focuses on methods for which ready-to-use implementations are available. We describe the main underlying assumptions, the main features, and advantages and limitations of each of the models. This descriptive summary constitutes a useful tool for driving methodological choices while analyzing OMICS data, especially in environmental epidemiology, where the emergence of the exposome concept clearly calls for unified methods to analyze marginally and jointly complex exposure and OMICS datasets. Copyright © 2013 Wiley Periodicals, Inc.

The ability of non-computer tasks to increase biomechanical exposure variability in computer-intensive office work.

PubMed

Barbieri, Dechristian França; Srinivasan, Divya; Mathiassen, Svend Erik; Nogueira, Helen Cristina; Oliveira, Ana Beatriz

2015-01-01

Postures and muscle activity in the upper body were recorded from 50 academics office workers during 2 hours of normal work, categorised by observation into computer work (CW) and three non-computer (NC) tasks (NC seated work, NC standing/walking work and breaks). NC tasks differed significantly in exposures from CW, with standing/walking NC tasks representing the largest contrasts for most of the exposure variables. For the majority of workers, exposure variability was larger in their present job than in CW alone, as measured by the job variance ratio (JVR), i.e. the ratio between min-min variabilities in the job and in CW. Calculations of JVRs for simulated jobs containing different proportions of CW showed that variability could, indeed, be increased by redistributing available tasks, but that substantial increases could only be achieved by introducing more vigorous tasks in the job, in casu illustrated by cleaning.

Developmental Exposure to Mild Variable Stress: Adult Offspring Performance in Trace Fear Conditioning after Prenatal and Postnatal Stress

EPA Science Inventory

In utero exposure to mild variable stress has been reported to influence learning and memory formation in offspring. Our research aims to examine whether nonchemical environmental stressors will exacerbate effects to chemical exposure. This study utilized a varying stress parad...

Long-term Neurotoxic Effects of Early-life Exposure to Tetrachloroethylene-contaminated Drinking Water.

PubMed

Aschengrau, Ann; Janulewicz, Patricia A; White, Roberta F; Vieira, Veronica M; Gallagher, Lisa G; Getz, Kelly D; Webster, Thomas F; Ozonoff, David M

2016-01-01

Tetrachloroethene (PCE) is a common environmental and occupational contaminant and an acknowledged neurotoxicant. From 1968 through 1983, widespread contamination of public drinking water supplies with PCE occurred in the Cape Cod region of Massachusetts. The source of the contamination was a vinyl liner applied to the inner surface of water distribution pipes. A retrospective cohort study (the Cape Cod Health Study) was undertaken to examine possible health consequences of early-life exposure to PCE-contaminated drinking water. This review describes the study methods and findings regarding the effects of prenatal and childhood exposure on neurologic outcomes during early adulthood, including vision, neuropsychological functioning, brain structure, risky behaviors, and mental illness. The review also describes the strengths and challenges of conducting population-based epidemiologic research in this unique setting. Participants were identified by cross-matching birth certificates and water system data. Information on health outcomes and confounding variables was collected from self-administered surveys (n = 1689), neuropsychological tests (n = 63), vision examinations (n = 63), and magnetic resonance imaging (n = 42). Early-life exposure to PCE was estimated using a leaching and transport model. The data analysis compared the occurrence of each health outcome among individuals with prenatal and early childhood PCE exposure to unexposed individuals while considering the effect of confounding variables. The study found evidence that early-life exposure to PCE-contaminated drinking water has long-term neurotoxic effects. The strongest associations were seen with illicit drug use, bipolar disorder, and post-traumatic stress disorder. Key strengths of the study were availability of historical data on affected water systems, a relatively high exposure prevalence and wide range of exposure levels, and little confounding. Challenges arose mainly from the historical nature of the exposure assessments. The Cape Cod Health Study demonstrates how scientists can take advantage of unique "natural experiments" to learn about the health effects of environmental pollution. This body of work has improved our understanding of the long-term health effects of early-life exposure to this common environmental contaminant and will help risk assessors and policymakers ensure that drinking water supplies in the United States are safe for vulnerable populations. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Metal(loid) bioaccessibility and inhalation risk assessment: A comparison between an urban and an industrial area.

PubMed

Hernández-Pellón, A; Nischkauer, W; Limbeck, A; Fernández-Olmo, I

2018-04-25

The content of metal(loid)s in particulate matter (PM) is of special concern due to their contribution to overall (PM) toxicity. In this study, the bioaccessibility and human health risk of potentially toxic metal(loid)s associated with PM 10 were investigated in two areas of the Cantabrian region (northern Spain) with different levels of exposure: an industrial area mainly influenced by a ferromanganese alloy plant; and an urban area consisting mainly of residential and commercial activities, but also affected, albeit to a lesser extent by the ferroalloy plant. Total content and bioaccessible fractions in simulated lung fluids (SLFs) of Fe, Mn, Zn, Ni, Cu, Sb, Mo, Cd and Pb were determined by ICP-MS. Gamble's solution and artificial lysosomal fluid (ALF) were used to mimic different conditions inside the human respiratory system. A health risk assessment was performed based on the United States Environmental Protection Agency's (USEPA) methodology. Most metal(loid)s showed moderate and high bioaccessibility in Gamble's solution and ALF, respectively. Despite the high variability between the samples, metal(loid) bioaccessibility was found to be higher on average at the industrial site, suggesting a greater hazard to human health in the proximity of the main metal(loid) sources. Based on the results of the risk assessment, the non-carcinogenic risk associated with Mn exposure was above the safe limit (HQ> 1) under all the studied scenarios at the industrial site and under some specific scenarios at the urban location. The estimated carcinogenic inhalation risk for Cd exposure at the industrial site was found to be within the range between 1.0 × 10 -6 to 1.0 × 10 -4 (uncertainty range) under some scenarios. The results obtained in this study indicate that Mn and Cd inhalation exposure occurring in the vicinities of the studied areas may pose a human health risk. Copyright © 2018 Elsevier Inc. All rights reserved.

Smokers’ compliance with smoke-free policies, and non-smokers’ assertiveness for smoke-free air in the workplace: a study from the Balkans.

PubMed

Lazuras, Lambros; Zlatev, Martin; Rodafinos, Angelos; Eiser, J Richard

2012-10-01

Identify the psychosocial variables that predict smokers’ compliance with smoke-free policies at work, and non-smokers’ assertiveness for smoke-free rights in Greek and Bulgarian workplaces. Data were collected from employees in Greece and Bulgaria. The main outcome measures were smokers’ compliance with smoke-free policies, and non-smokers’ assertiveness intentions. Demographic variables, tobacco use and dependence, as well as beliefs about second-hand smoke (SHS) exposure and smoking at work were also assessed. Regression analyses showed that smokers’ compliance with smoke-free policies was predicted by age, perceived health risks of smoking, and beliefs related to the benefits of smoking at work. Non-smokers’ assertiveness was predicted by annoyance from exposure to SHS at work, and assertiveness-related social cognitions (e.g., attitudes, social norms, and self-efficacy). Interventions to promote support for tobacco control policies at work in Greece and Bulgaria may benefit from targeting smokers’ beliefs about the actual effects of tobacco use on health and job performance. Accordingly, efforts to promote non-smokers assertiveness should build stronger assertiveness-related attitudes, convey anti-smoking normative messages, and strengthen self-efficacy skills.

Air Pollution and Nonmalignant Respiratory Mortality in 16 Cohorts within the ESCAPE Project

PubMed Central

Dimakopoulou, Konstantina; Samoli, Evangelia; Beelen, Rob; Stafoggia, Massimo; Andersen, Zorana Jovanovic; Hoffmann, Barbara; Fischer, Paul; Nieuwenhuijsen, Mark; Vineis, Paolo; Xun, Wei; Hoek, Gerard; Raaschou-Nielsen, Ole; Oudin, Anna; Forsberg, Bertil; Modig, Lars; Jousilahti, Pekka; Lanki, Timo; Turunen, Anu; Oftedal, Bente; Nafstad, Per; Schwarze, Per E.; Penell, Johanna; Fratiglioni, Laura; Andersson, Niklas; Pedersen, Nancy; Korek, Michal; De Faire, Ulf; Eriksen, Kirsten Thorup; Tjønneland, Anne; Becker, Thomas; Wang, Meng; Bueno-de-Mesquita, Bas; Tsai, Ming-Yi; Eeftens, Marloes; Peeters, Petra H.; Meliefste, Kees; Marcon, Alessandro; Krämer, Ursula; Kuhlbusch, Thomas A.J.; Vossoughi, Mohammad; Key, Timothy; de Hoogh, Kees; Hampel, Regina; Peters, Annette; Heinrich, Joachim; Weinmayr, Gudrun; Concin, Hans; Nagel, Gabriele; Ineichen, Alex; Jacquemin, Bénédicte; Stempfelet, Morgane; Vilier, Alice; Ricceri, Fulvio; Sacerdote, Carlotta; Pedeli, Xanthi; Katsoulis, Michalis; Trichopoulou, Antonia; Brunekreef, Bert

2014-01-01

Rationale: Prospective cohort studies have shown that chronic exposure to particulate matter and traffic-related air pollution is associated with reduced survival. However, the effects on nonmalignant respiratory mortality are less studied, and the data reported are less consistent. Objectives: We have investigated the relationship of long-term exposure to air pollution and nonmalignant respiratory mortality in 16 cohorts with individual level data within the multicenter European Study of Cohorts for Air Pollution Effects (ESCAPE). Methods: Data from 16 ongoing cohort studies from Europe were used. The total number of subjects was 307,553. There were 1,559 respiratory deaths during follow-up. Measurements and Main Results: Air pollution exposure was estimated by land use regression models at the baseline residential addresses of study participants and traffic-proximity variables were derived from geographical databases following a standardized procedure within the ESCAPE study. Cohort-specific hazard ratios obtained by Cox proportional hazard models from standardized individual cohort analyses were combined using metaanalyses. We found no significant associations between air pollution exposure and nonmalignant respiratory mortality. Most hazard ratios were slightly below unity, with the exception of the traffic-proximity indicators. Conclusions: In this study of 16 cohorts, there was no association between air pollution exposure and nonmalignant respiratory mortality. PMID:24521254

On the equivalence of case-crossover and time series methods in environmental epidemiology.

PubMed

Lu, Yun; Zeger, Scott L

2007-04-01

The case-crossover design was introduced in epidemiology 15 years ago as a method for studying the effects of a risk factor on a health event using only cases. The idea is to compare a case's exposure immediately prior to or during the case-defining event with that same person's exposure at otherwise similar "reference" times. An alternative approach to the analysis of daily exposure and case-only data is time series analysis. Here, log-linear regression models express the expected total number of events on each day as a function of the exposure level and potential confounding variables. In time series analyses of air pollution, smooth functions of time and weather are the main confounders. Time series and case-crossover methods are often viewed as competing methods. In this paper, we show that case-crossover using conditional logistic regression is a special case of time series analysis when there is a common exposure such as in air pollution studies. This equivalence provides computational convenience for case-crossover analyses and a better understanding of time series models. Time series log-linear regression accounts for overdispersion of the Poisson variance, while case-crossover analyses typically do not. This equivalence also permits model checking for case-crossover data using standard log-linear model diagnostics.

Respiratory symptoms, lung function, and sensitisation to flour in a British bakery.

PubMed Central

Musk, A W; Venables, K M; Crook, B; Nunn, A J; Hawkins, R; Crook, G D; Graneek, B J; Tee, R D; Farrer, N; Johnson, D A

1989-01-01

A survey of dust exposure, respiratory symptoms, lung function, and response to skin prick tests was conducted in a modern British bakery. Of the 318 bakery employees, 279 (88%) took part. Jobs were ranked from 0 to 10 by perceived dustiness and this ranking correlated well with total dust concentration measured in 79 personal dust samples. Nine samples had concentrations greater than 10 mg/m3, the exposure limit for nuisance dust. All participants completed a self administered questionnaire on symptoms and their relation to work. FEV1 and FVC were measured by a dry wedge spirometer and bronchial reactivity to methacholine was estimated. Skin prick tests were performed with three common allergens and with 11 allergens likely to be found in bakery dust, including mites and moulds. Of the participants in the main exposure group, 35% reported chest symptoms which in 13% were work related. The corresponding figures for nasal symptoms were 38% and 19%. Symptoms, lung function, bronchial reactivity, and response to skin prick tests were related to current or past exposure to dust using logistic or linear regression analysis as appropriate. Exposure rank was significantly associated with most of the response variables studied. The study shows that respiratory symptoms and sensitisation are common, even in a modern bakery. PMID:2789967

Engagement in community activities and trust in local leaders as concomitants of psychological distress among Israeli civilians exposed to prolonged rocket attacks.

PubMed

Zanbar, Lea; Kaniasty, Krzysztof; Ben-Tzur, Navit

2018-07-01

Present study, conducted in the aftermath of the 2014 Israel-Gaza conflict, investigated psychological toll of exposure to rockets attacks in a sample of residents of central and southern Israel. Analyses focused on the distress-protective functions of collectively grounded resources: engagement in community activities and trust in local leadership. This cross-sectional study was conducted between 2 and 3 months after the hostilities. Participants (N = 764) were recruited by an online survey company that distributed a questionnaire assessing, in addition to focal predictors, sociodemographic factors and prior exposure to trauma. The outcome variables were post-traumatic stress disorder (PTSD) and nonspecific distress symptoms. Conservative regression analyses revealed that greater exposure to rocket attacks was predictive of higher levels of posttraumatic stress symptoms. Higher engagement in community activities exhibited a partial trauma-buffering function. However, higher levels of trust in local leaders appeared to exacerbate, rather than diminish, negative impact of rocket exposure on PTSD. Symptoms of psychological distress were not influenced neither by trauma exposure nor by stressor interactions with resources. Trust in local leadership exerted a beneficial main effect on distress. Collectively based resources are important for coping in times of community-wide stressors, yet their role is complex.

Rigorous tests of gene-environment interactions in a lab study of the oxytocin receptor gene (OXTR), alcohol exposure, and aggression.

PubMed

LoParo, Devon; Johansson, Ada; Walum, Hasse; Westberg, Lars; Santtila, Pekka; Waldman, Irwin

2016-07-01

Naturalistic studies of gene-environment interactions (G X E) have been plagued by several limitations, including difficulty isolating specific environmental risk factors from other correlated aspects of the environment, gene-environment correlation (rGE ), and the use of a single genetic variant to represent the influence of a gene. We present results from 235 Finnish young men in two lab studies of aggression and alcohol challenge that attempt to redress these limitations of the extant G X E literature. Specifically, we use a latent variable modeling approach in an attempt to more fully account for genetic variation across the oxytocin receptor gene (OXTR) and to robustly test its main effects on aggression and its interaction with alcohol exposure. We also modeled aggression as a latent variable comprising various indices, including the average and maximum levels of aggression, the earliest trial on which aggression was expressed, and the proportion of trials on which the minimum and maximum levels of aggression were expressed. The best fitting model for the genetic variation across OXTR included six factors derived from an exploratory factor analysis, roughly corresponding to six haplotype blocks. Aggression levels were higher on trials in which participants were administered alcohol, won, or were provoked. There was a significant main effect of OXTR on aggression across studies after controlling for covariates. The interaction of OXTR and alcohol was also significant across studies, such that OXTR had stronger effects on aggression in the alcohol administration condition. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Responses of bay anchovy (Anchoa mitchilli) larvae under lethal and sublethal scenarios of crude oil exposure.

PubMed

Duffy, Tara A; Childress, William; Portier, Ralph; Chesney, Edward J

2016-12-01

Bay anchovy (Anchoa mitchilli) is an ecologically important zooplanktivorous fish inhabiting estuaries of the Gulf of Mexico and eastern North America from Maine to Florida. Because they have a protracted spawning season (spring through fall) and are abundant at all life stages in coastal estuaries, their eggs and larvae likely encountered oil that reached the coast during the Deepwater Horizon oil spill. We compared responses to oil exposure at different life stages and at lethal and sublethal conditions using acute, 24h exposures. In a series of experiments, bay anchovy larvae were exposed to high energy water accommodated fractions (HEWAF) and chemically-enhanced WAF (CEWAF) at two stages of larval development (5 and 21 days post hatch, dph). HEWAF oil exposures induced significantly greater life stage dependent sensitivity at 5 dph than at 21 dph but chemically dispersed (CEWAF) exposure mortality was more variable and LC 50s were not significantly different between 5 and 21dph larvae. Acute exposure to two low-level concentrations of CEWAF did not result in significant mortality over 24h, but resulted in a 25-77% reduction in larval survival and a 12-34% reduction in weight specific growth after six days of post-exposure growth following the initial 24h exposure. These results show that younger (5 dph) bay anchovy larvae are more vulnerable to acute oil exposure than older (21 dph) larvae, and that acute responses do not accurately reflect potential population level mortality and impacts to growth and development. Copyright © 2016 Elsevier Inc. All rights reserved.

MobRISK: a model for assessing the exposure of road users to flash flood events

NASA Astrophysics Data System (ADS)

Shabou, Saif; Ruin, Isabelle; Lutoff, Céline; Debionne, Samuel; Anquetin, Sandrine; Creutin, Jean-Dominique; Beaufils, Xavier

2017-09-01

Recent flash flood impact studies highlight that road networks are often disrupted due to adverse weather and flash flood events. Road users are thus particularly exposed to road flooding during their daily mobility. Previous exposure studies, however, do not take into consideration population mobility. Recent advances in transportation research provide an appropriate framework for simulating individual travel-activity patterns using an activity-based approach. These activity-based mobility models enable the prediction of the sequence of activities performed by individuals and locating them with a high spatial-temporal resolution. This paper describes the development of the MobRISK microsimulation system: a model for assessing the exposure of road users to extreme hydrometeorological events. MobRISK aims at providing an accurate spatiotemporal exposure assessment by integrating travel-activity behaviors and mobility adaptation with respect to weather disruptions. The model is applied in a flash-flood-prone area in southern France to assess motorists' exposure to the September 2002 flash flood event. The results show that risk of flooding mainly occurs in principal road links with considerable traffic load. However, a lag time between the timing of the road submersion and persons crossing these roads contributes to reducing the potential vehicle-related fatal accidents. It is also found that sociodemographic variables have a significant effect on individual exposure. Thus, the proposed model demonstrates the benefits of considering spatiotemporal dynamics of population exposure to flash floods and presents an important improvement in exposure assessment methods. Such improved characterization of road user exposures can present valuable information for flood risk management services.

Heavy metals in drinking water: Occurrences, implications, and future needs in developing countries.

PubMed

Chowdhury, Shakhawat; Mazumder, M A Jafar; Al-Attas, Omar; Husain, Tahir

2016-11-01

Heavy metals in drinking water pose a threat to human health. Populations are exposed to heavy metals primarily through water consumption, but few heavy metals can bioaccumulate in the human body (e.g., in lipids and the gastrointestinal system) and may induce cancer and other risks. To date, few thousand publications have reported various aspects of heavy metals in drinking water, including the types and quantities of metals in drinking water, their sources, factors affecting their concentrations at exposure points, human exposure, potential risks, and their removal from drinking water. Many developing countries are faced with the challenge of reducing human exposure to heavy metals, mainly due to their limited economic capacities to use advanced technologies for heavy metal removal. This paper aims to review the state of research on heavy metals in drinking water in developing countries; understand their types and variability, sources, exposure, possible health effects, and removal; and analyze the factors contributing to heavy metals in drinking water. This study identifies the current challenges in developing countries, and future research needs to reduce the levels of heavy metals in drinking water. Copyright © 2016 Elsevier B.V. All rights reserved.

Modeling Spatial and Temporal Variability of Residential Air Exchange Rates for the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS)

EPA Science Inventory

Air pollution health studies often use outdoor concentrations as exposure surrogates. Failure to account for variability of residential infiltration of outdoor pollutants can induce exposure errors and lead to bias and incorrect confidence intervals in health effect estimates. Th...

Systemic Exposure to Thiopurines and Risk of Relapse in Children with Acute Lymphoblastic Leukemia: A Children’s Oncology Group Study

PubMed Central

Bhatia, Smita; Landier, Wendy; Hageman, Lindsey; Chen, Yanjun; Kim, Heeyoung; Sun, Can-Lan; Kornegay, Nancy; Evans, William E; Angiolillo, Anne L; Bostrom, Bruce; Casillas, Jacqueline; Lew, Glen; Maloney, Kelly W; Mascarenhas, Leo; Ritchey, A. Kim; Termuhlen, Amanda M; Carroll, William L; Wong, F Lennie; Relling, Mary V

2015-01-01

Importance Variability in prescribed 6-mercaptopurine and lack of adherence to 6-mercaptopurine could result in intra-individual variability in systemic exposure to 6-mercaptopurine (measured as erythrocyte thioguanine nucleotide levels) in children with acute lymphoblastic leukemia. The impact of intra-individual variability in systemic exposure to 6-mercaptopurine on relapse risk is unknown. Objective To determine impact of high intra-individual variability in 6-mercaptopurine systemic exposure on relapse risk in children with acute lymphoblastic leukemia. Design Prospective longitudinal design; daily adherence monitoring, 6-mercaptopurine dose-intensity and erythrocyte thioguanine nucleotide levels (pmol/8*10^8 erythrocytes) measured for 6 consecutive months per patient; cohort followed for a median of 6.7 years from diagnosis. Setting Children’s Oncology Group study (COG-AALL03N1); 94 participating institutions; ambulatory care setting. Participants Participants included 742 children meeting the following eligibility criteria: diagnosis of acute lymphoblastic leukemia at ≤21 years; in first continuous remission at study entry; receiving self/parent/caregiver-administered oral 6-mercaptopurine during maintenance. Median age at diagnosis: 5 years; 68% were male; 43% with NCI-based high-risk disease. Main Outcome Measures Adherence measured electronically using Medication Event Monitoring System that recorded date/time of each 6-mercaptopurine bottle opening; adherence rate defined as ratio of days of 6-mercaptopurine bottle opened to days when 6-mercaptopurine prescribed. 6-mercaptopurine doses actually prescribed were divided by planned protocol doses (75mg/m2/day) to compute average monthly dose-intensity. Electronically-monitored adherence (68,716 person-days), 6-mercaptopurine dose-intensity (120,439 person-days) and monthly erythrocyte thioguanine nucleotide levels (n=3,944 measurements) contributed to the analysis. Using intra-individual coefficients of variation (CV %), patients were classified as having stable (CV % <85th percentile) vs. varying (CV % ≥85th percentile) indices. Results Adjusting for clinical prognosticators, patients with 6-mercaptopurine non-adherence (mean adherence rate <95%) were at a 2.7 fold increased risk of relapse (95% confidence interval [CI], 1.3 to 5.6, p=0.01). Among adherers, high intra-individual variability in thioguanine nucleotide levels contributes to increased relapse risk (HR=4.4, 95% CI, 1.2 to 15.7, p=0.02). Furthermore, adherers with varying thioguanine nucleotide levels had varying 6-mercaptopurine dose-intensity (OR=4.5, p=0.006) and 6-mercaptopurine drug interruptions (OR=10.2, p=0.003). Conclusions and Relevance These findings emphasize the need to maximize 6-mercaptopurine adherence and maintain steady thiopurine exposure to minimize relapse in children with acute lymphoblastic leukemia. PMID:26181173

Instrumental Variable Analysis with a Nonlinear Exposure–Outcome Relationship

PubMed Central

Davies, Neil M.; Thompson, Simon G.

2014-01-01

Background: Instrumental variable methods can estimate the causal effect of an exposure on an outcome using observational data. Many instrumental variable methods assume that the exposure–outcome relation is linear, but in practice this assumption is often in doubt, or perhaps the shape of the relation is a target for investigation. We investigate this issue in the context of Mendelian randomization, the use of genetic variants as instrumental variables. Methods: Using simulations, we demonstrate the performance of a simple linear instrumental variable method when the true shape of the exposure–outcome relation is not linear. We also present a novel method for estimating the effect of the exposure on the outcome within strata of the exposure distribution. This enables the estimation of localized average causal effects within quantile groups of the exposure or as a continuous function of the exposure using a sliding window approach. Results: Our simulations suggest that linear instrumental variable estimates approximate a population-averaged causal effect. This is the average difference in the outcome if the exposure for every individual in the population is increased by a fixed amount. Estimates of localized average causal effects reveal the shape of the exposure–outcome relation for a variety of models. These methods are used to investigate the relations between body mass index and a range of cardiovascular risk factors. Conclusions: Nonlinear exposure–outcome relations should not be a barrier to instrumental variable analyses. When the exposure–outcome relation is not linear, either a population-averaged causal effect or the shape of the exposure–outcome relation can be estimated. PMID:25166881

Second-hand smoke exposure in 4-year-old children in Spain: Sources, associated factors and urinary cotinine.

PubMed

Aurrekoetxea, Juan José; Murcia, Mario; Rebagliato, Marisa; Guxens, Mònica; Fernández-Somoano, Ana; López, María José; Lertxundi, Aitana; Castilla, Ane Miren; Espada, Mercedes; Tardón, Adonina; Ballester, Ferran; Santa-Marina, Loreto

2016-02-01

Second-hand smoke exposure (SHS) in children remains as a major pollution problem, with important consequences for children's health. This study aimed to identify the sources of exposure to SHS among 4-year-old children, comparing self-reports to a urinary biomarker of exposure, and characterize the most important variables related to SHS exposure in this population. 4-year-old children's exposure to SHS was assessed by a parental-reported questionnaire and by urinary cotinine (UC) measurements in 1757 participants from 4 different areas of the Spanish INMA (INfancia y Medio Ambiente - Environment and Childhood) Project. The questionnaire about SHS included information about smoking habits at home by household members, and about exposure to SHS in other places including other homes, bars, restaurants or transportation. The association between quantified UC levels (>4ng/ml) and sociodemographic variables and the different sources of SHS exposure was examined using logistic regression. Based on parental reports, 21.6% of the children were exposed to SHS at home and 47.1% elsewhere; making a total 55.9% of the children exposed to SHS. In addition, 28.2% of the children whose parents reported being not regularly exposed to SHS had quantified UC values. Children from younger mothers (<34 vs. ≥39.4 y) had a higher odds of exposure to SHS [OR (95% CI): 2.28 (1.70-3.05) per year], as well as from families with a lower educational level [OR secondary: 2.12 (1.69-2.65); primary or less: 2.91 (2.19-3.88)]. The odds of quantifiable UC in children dropped after the smoking ban in public places [OR=0.59 (0.42-0.83)]. Regarding the sources of SHS exposure we observed that quantifiable UC odds was increased in children whose parents smoked at home in their presence [OR mother occasionally: 13.39 (7.03-25.50); mother often: 18.48 (8.40-40.66); father occasionally: 10.98 (6.52-18.49); father often: 11.50 (5.96-22.20)] or in children attending other confined places, mainly other houses where people smoked [OR: 2.23 (1.78-2.80)]. Children's SHS exposure is nowadays an unresolved major public health problem in Spain. After the ban of smoking in public places health care professionals should put more emphasis to the parents on the importance of controlling the exposure of their children in private spaces. Copyright © 2015 Elsevier Inc. All rights reserved.

Robust best linear estimator for Cox regression with instrumental variables in whole cohort and surrogates with additive measurement error in calibration sample

PubMed Central

Wang, Ching-Yun; Song, Xiao

2017-01-01

SUMMARY Biomedical researchers are often interested in estimating the effect of an environmental exposure in relation to a chronic disease endpoint. However, the exposure variable of interest may be measured with errors. In a subset of the whole cohort, a surrogate variable is available for the true unobserved exposure variable. The surrogate variable satisfies an additive measurement error model, but it may not have repeated measurements. The subset in which the surrogate variables are available is called a calibration sample. In addition to the surrogate variables that are available among the subjects in the calibration sample, we consider the situation when there is an instrumental variable available for all study subjects. An instrumental variable is correlated with the unobserved true exposure variable, and hence can be useful in the estimation of the regression coefficients. In this paper, we propose a nonparametric method for Cox regression using the observed data from the whole cohort. The nonparametric estimator is the best linear combination of a nonparametric correction estimator from the calibration sample and the difference of the naive estimators from the calibration sample and the whole cohort. The asymptotic distribution is derived, and the finite sample performance of the proposed estimator is examined via intensive simulation studies. The methods are applied to the Nutritional Biomarkers Study of the Women’s Health Initiative. PMID:27546625

Levels and predictors of airborne and internal exposure to chromium and nickel among welders--results of the WELDOX study.

PubMed

Weiss, Tobias; Pesch, Beate; Lotz, Anne; Gutwinski, Eleonore; Van Gelder, Rainer; Punkenburg, Ewald; Kendzia, Benjamin; Gawrych, Katarzyna; Lehnert, Martin; Heinze, Evelyn; Hartwig, Andrea; Käfferlein, Heiko U; Hahn, Jens-Uwe; Brüning, Thomas

2013-03-01

The objective of this analysis was to investigate levels and determinants of exposure to airborne and urinary chromium (Cr, CrU) and nickel (Ni, NiU) among 241 welders. Respirable and inhalable welding fume was collected during a shift, and the metal content was determined using inductively coupled plasma mass spectrometry. In post-shift urine, CrU and NiU were measured by means of graphite furnace atom absorption spectrometry, with resulting concentrations varying across a wide range. Due to a large fraction below the limits of quantitation we applied multiple imputations to the log-transformed exposure variables for the analysis of the data. Respirable Cr and Ni were about half of the concentrations of inhalable Cr and Ni, respectively. CrU and NiU were determined with medians of 1.2 μg/L (interquartile range <1.00; 3.61) and 2.9 μg/L (interquartile range <1.50; 5.97). Furthermore, Cr and Ni correlated in respirable welding fume (r=0.79, 95% CI 0.74-0.85) and urine (r=0.55, 95% CI 0.44-0.65). Regression models identified exposure-modulating variables in form of multiplicative factors and revealed slightly better model fits for Cr (R(2) respirable Cr 48%, CrU 55%) than for Ni (R(2) respirable Ni 42%, NiU 38%). The air concentrations were mainly predicted by the metal content in electrodes or base material in addition to the welding technique. Respirable Cr and Ni were good predictors for CrU and NiU, respectively. Exposure was higher when welding was performed in confined spaces or with inefficient ventilation, and lower in urine when respirators were used. In conclusion, statistical modelling allowed the evaluation of determinants of internal and external exposure to Cr and Ni in welders. Welding parameters were stronger predictors than workplace conditions. Airborne exposure was lowest inside respirators with supply of purified air. Copyright © 2012 Elsevier GmbH. All rights reserved.

VizieR Online Data Catalog: Variable stars in the M16-M17 field (Maffei+ 1999)

NASA Astrophysics Data System (ADS)

Maffei, P.; Tosti, G.

2013-07-01

The original work was published as a paper book by the Perugia University in 1999. Before that, only the variable stars list (coordinates, classifications, periods, epochs, magnitude ranges) was published (P. Maffei, 1975IBVS..985....1M) The photographic material was discontinuously collected with the two Schmidt telescopes of the Asiago Observatory and with the Schmidt telescope of the Catania Astrophysical Observatory in the years 1961 to 1991. 103a-O without or with filter GG13 and hypersensitized with NH3 or pre-flashed I-N+RG5 were used. Date, JD, exposure time, emulsion/filter combination and the observer for each plate are listed in Table 1 and Table 2. The variable search was carried out with the blink microscope plate comparator of the Asiago Observatory. Details about the history and the reduction of the observational material are given in the "main.htm" file; the digitization was made by Alessandro Nesci. (7 data files).

Reliability of Current Biokinetic and Dosimetric Models for Radionuclides: A Pilot Study

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

Leggett, Richard Wayne; Eckerman, Keith F; Meck, Robert A.

2008-10-01

This report describes the results of a pilot study of the reliability of the biokinetic and dosimetric models currently used by the U.S. Nuclear Regulatory Commission (NRC) as predictors of dose per unit internal or external exposure to radionuclides. The study examines the feasibility of critically evaluating the accuracy of these models for a comprehensive set of radionuclides of concern to the NRC. Each critical evaluation would include: identification of discrepancies between the models and current databases; characterization of uncertainties in model predictions of dose per unit intake or unit external exposure; characterization of variability in dose per unit intakemore » or unit external exposure; and evaluation of prospects for development of more accurate models. Uncertainty refers here to the level of knowledge of a central value for a population, and variability refers to quantitative differences between different members of a population. This pilot study provides a critical assessment of models for selected radionuclides representing different levels of knowledge of dose per unit exposure. The main conclusions of this study are as follows: (1) To optimize the use of available NRC resources, the full study should focus on radionuclides most frequently encountered in the workplace or environment. A list of 50 radionuclides is proposed. (2) The reliability of a dose coefficient for inhalation or ingestion of a radionuclide (i.e., an estimate of dose per unit intake) may depend strongly on the specific application. Multiple characterizations of the uncertainty in a dose coefficient for inhalation or ingestion of a radionuclide may be needed for different forms of the radionuclide and different levels of information of that form available to the dose analyst. (3) A meaningful characterization of variability in dose per unit intake of a radionuclide requires detailed information on the biokinetics of the radionuclide and hence is not feasible for many infrequently studied radionuclides. (4) The biokinetics of a radionuclide in the human body typically represents the greatest source of uncertainty or variability in dose per unit intake. (5) Characterization of uncertainty in dose per unit exposure is generally a more straightforward problem for external exposure than for intake of a radionuclide. (6) For many radionuclides the most important outcome of a large-scale critical evaluation of databases and biokinetic models for radionuclides is expected to be the improvement of current models. Many of the current models do not fully or accurately reflect available radiobiological or physiological information, either because the models are outdated or because they were based on selective or uncritical use of data or inadequate model structures. In such cases the models should be replaced with physiologically realistic models that incorporate a wider spectrum of information.« less

A land-use regression model for estimating microenvironmental diesel exposure given multiple addresses from birth through childhood.

PubMed

Ryan, Patrick H; Lemasters, Grace K; Levin, Linda; Burkle, Jeff; Biswas, Pratim; Hu, Shaohua; Grinshpun, Sergey; Reponen, Tiina

2008-10-01

The Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) is a prospective birth cohort whose purpose is to determine if exposure to high levels of diesel exhaust particles (DEP) during early childhood increases the risk for developing allergic diseases. In order to estimate exposure to DEP, a land-use regression (LUR) model was developed using geographic data as independent variables and sampled levels of a marker of DEP as the dependent variable. A continuous wind direction variable was also created. The LUR model predicted 74% of the variability in sampled values with four variables: wind direction, length of bus routes within 300 m of the sample site, a measure of truck intensity within 300 m of the sampling site, and elevation. The LUR model was subsequently applied to all locations where the child had spent more than eight hours per week from through age three. A time-weighted average (TWA) microenvironmental exposure estimate was derived for four time periods: 0-6 months, 7-12 months, 13-24 months, 25-36 months. By age two, one third of the children were spending significant time at locations other than home and by 36 months, 39% of the children had changed their residential addresses. The mean cumulative DEP exposure estimate increased from age 6 to 36 months from 70 to 414 microg/m3-days. Findings indicate that using birth addresses to estimate a child's exposure may result in exposure misclassification for some children who spend a significant amount of time at a location with high exposure to DEP.

Short-term exposure to air pollutants increases the risk of ST elevation myocardial infarction and of infarct-related ventricular arrhythmias and mortality.

PubMed

Bañeras, Jordi; Ferreira-González, Ignacio; Marsal, Josep Ramon; Barrabés, José A; Ribera, Aida; Lidón, Rosa Maria; Domingo, Enric; Martí, Gerard; García-Dorado, David

2018-01-01

The relation between STEMI and air pollution (AP) is scant. We aimed to investigate the short term association between AP and the incidence of STEMI, and STEMI-related ventricular arrhythmias (VA) and mortality. The study was carried out in the area of Barcelona from January 2010 to December 2011. Daily STEMI rates and incidence of STEMI-related VA and mortality were obtained prospectively. The corresponding daily levels of the main pollutants were recorded as well as the atmospheric variables. Three cohorts were defined in order to minimize exposure bias. The magnitude of association was estimated using a time-series design and was adjusted according to atmospheric variables. The daily rate of hospital admissions for STEMI was associated with increases in PM 2.5, PM 10, lead and NO2 concentrations. VA incidence and mortality were associated with increases in PM 2.5 and PM 10 concentrations. In the most specific cohort, BCN (Barcelona) Attended & Resident, STEMI incidence was associated with increases in PM 2.5 (1.009% per 10μg/m 3 ) and PM 10 concentrations (1.005% per 10μg/m 3 ). VA was associated with increases in PM 2.5 (1.021%) and PM 10 (1.015%) and mortality was associated with increases in PM 2.5 (1.083%) and PM 10 (1.045%). Short-term exposure to high levels of PM 2.5 and PM 10 is associated with increased daily STEMI admissions and STEMI-related VA and mortality. Exposure to high levels of lead and NO2 is associated with increased daily STEMI admissions, and NO2 with higher mortality in STEMI patients. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Quantitative, depth-resolved determination of particle motion using multi-exposure, spatial frequency domain laser speckle imaging.

PubMed

Rice, Tyler B; Kwan, Elliott; Hayakawa, Carole K; Durkin, Anthony J; Choi, Bernard; Tromberg, Bruce J

2013-01-01

Laser Speckle Imaging (LSI) is a simple, noninvasive technique for rapid imaging of particle motion in scattering media such as biological tissue. LSI is generally used to derive a qualitative index of relative blood flow due to unknown impact from several variables that affect speckle contrast. These variables may include optical absorption and scattering coefficients, multi-layer dynamics including static, non-ergodic regions, and systematic effects such as laser coherence length. In order to account for these effects and move toward quantitative, depth-resolved LSI, we have developed a method that combines Monte Carlo modeling, multi-exposure speckle imaging (MESI), spatial frequency domain imaging (SFDI), and careful instrument calibration. Monte Carlo models were used to generate total and layer-specific fractional momentum transfer distributions. This information was used to predict speckle contrast as a function of exposure time, spatial frequency, layer thickness, and layer dynamics. To verify with experimental data, controlled phantom experiments with characteristic tissue optical properties were performed using a structured light speckle imaging system. Three main geometries were explored: 1) diffusive dynamic layer beneath a static layer, 2) static layer beneath a diffuse dynamic layer, and 3) directed flow (tube) submerged in a dynamic scattering layer. Data fits were performed using the Monte Carlo model, which accurately reconstructed the type of particle flow (diffusive or directed) in each layer, the layer thickness, and absolute flow speeds to within 15% or better.

Assessing Spatial and Temporal Variability of VOCs and PM-Components in Outdoor Air during the Detroit Exposure and Aerosol Research Study (DEARS)

EPA Science Inventory

Exposure models for air pollutants often adjust for effects of the physical environment (e.g., season, urban vs. rural populations) in order to improve exposure and risk predictions. Yet attempts are seldom made to attribute variability in observed outdoor air measurements to spe...

Characterizing relationships between personal exposures to VOCs and socioeconomic, demographic, behavioral variables

NASA Astrophysics Data System (ADS)

Wang, Sheng-Wei; Majeed, Mohammed A.; Chu, Pei-Ling; Lin, Hui-Chih

Socioeconomic and demographic factors have been found to significantly affect time-activity patterns in population cohorts that can subsequently influence personal exposures to air pollutants. This study investigates relationships between personal exposures to eight VOCs (benzene, toluene, ethylbenzene, o-xylene, m-,p-xylene, chloroform, 1,4-dichlorobenzene, and tetrachloroethene) and socioeconomic, demographic, time-activity pattern factors using data collected from the 1999-2000 National Health and Nutrition Examination Survey (NHANES) VOC study. Socio-demographic factors (such as race/ethnicity and family income) were generally found to significantly influence personal exposures to the three chlorinated compounds. This was mainly due to the associations paired by race/ethnicity and urban residence, race/ethnicity and use of air freshener in car, family income and use of dry-cleaner, which can in turn affect exposures to chloroform, 1,4-dichlorobenzene, and tetrachloroethene, respectively. For BTEX, the traffic-related compounds, housing characteristics (leaving home windows open and having an attached garage) and personal activities related to the uses of fuels or solvent-related products played more significant roles in influencing exposures. Significant differences in BTEX exposures were also commonly found in relation to gender, due to associated significant differences in time spent at work/school and outdoors. The coupling of Classification and Regression Tree (CART) and Bootstrap Aggregating (Bagging) techniques were used as effective tools for characterizing robust sets of significant VOC exposure factors presented above, which conventional statistical approaches could not accomplish. Identification of these significant VOC exposure factors can be used to generate hypotheses for future investigations about possible significant VOC exposure sources and pathways in the general U.S. population.

Sun exposure, vitamin D receptor polymorphisms FokI and BsmI and risk of multiple primary melanoma.

PubMed

Mandelcorn-Monson, Rochelle; Marrett, Loraine; Kricker, Anne; Armstrong, Bruce K; Orlow, Irene; Goumas, Chris; Paine, Susan; Rosso, Stefano; Thomas, Nancy; Millikan, Robert C; Pole, Jason D; Cotignola, Javier; Rosen, Cheryl; Kanetsky, Peter A; Lee-Taylor, Julia; Begg, Colin B; Berwick, Marianne

2011-12-01

Sunlight exposure increases risk of melanoma. Sunlight also potentiates cutaneous synthesis of vitamin D, which can inhibit melanoma cell growth and promote apoptosis. Vitamin D effects are mediated through the vitamin D receptor (VDR). We hypothesized that genetic variation in VDR affects the relationship of sun exposure to risk of a further melanoma in people who have already had one. We investigated the interaction between VDR polymorphisms and sun exposure in a population-based multinational study comparing 1138 patients with a multiple (second or subsequent) primary melanoma (cases) to 2151 patients with a first primary melanoma (controls); essentially a case-control study of melanoma in a population of melanoma survivors. Sun exposure was assessed using a questionnaire and interview, and was shown to be associated with multiple primary melanoma. VDR was genotyped at the FokI and BsmI loci and the main effects of variants at these loci and their interactions with sun exposure were analyzed. Only the BsmI variant was associated with multiple primary melanoma (OR=1.27, 95% CI 0.99-1.62 for the homozygous variant genotype). Joint effects analyses showed highest ORs in the high exposure, homozygous variant BsmI genotype category for each sun exposure variable. Stratified analyses showed somewhat higher ORs for the homozygous BsmI variant genotype in people with high sun exposure than with low sun exposure. P values for interaction, however, were high. These results suggest that risk of multiple primary melanoma is increased in people who have the BsmI variant of VDR. Copyright © 2011 Elsevier Ltd. All rights reserved.

Modelling ecological and human exposure to POPs in Venice lagoon - Part II: Quantitative uncertainty and sensitivity analysis in coupled exposure models.

PubMed

Radomyski, Artur; Giubilato, Elisa; Ciffroy, Philippe; Critto, Andrea; Brochot, Céline; Marcomini, Antonio

2016-11-01

The study is focused on applying uncertainty and sensitivity analysis to support the application and evaluation of large exposure models where a significant number of parameters and complex exposure scenarios might be involved. The recently developed MERLIN-Expo exposure modelling tool was applied to probabilistically assess the ecological and human exposure to PCB 126 and 2,3,7,8-TCDD in the Venice lagoon (Italy). The 'Phytoplankton', 'Aquatic Invertebrate', 'Fish', 'Human intake' and PBPK models available in MERLIN-Expo library were integrated to create a specific food web to dynamically simulate bioaccumulation in various aquatic species and in the human body over individual lifetimes from 1932 until 1998. MERLIN-Expo is a high tier exposure modelling tool allowing propagation of uncertainty on the model predictions through Monte Carlo simulation. Uncertainty in model output can be further apportioned between parameters by applying built-in sensitivity analysis tools. In this study, uncertainty has been extensively addressed in the distribution functions to describe the data input and the effect on model results by applying sensitivity analysis techniques (screening Morris method, regression analysis, and variance-based method EFAST). In the exposure scenario developed for the Lagoon of Venice, the concentrations of 2,3,7,8-TCDD and PCB 126 in human blood turned out to be mainly influenced by a combination of parameters (half-lives of the chemicals, body weight variability, lipid fraction, food assimilation efficiency), physiological processes (uptake/elimination rates), environmental exposure concentrations (sediment, water, food) and eating behaviours (amount of food eaten). In conclusion, this case study demonstrated feasibility of MERLIN-Expo to be successfully employed in integrated, high tier exposure assessment. Copyright © 2016 Elsevier B.V. All rights reserved.

Variability and epistemic uncertainty in water ingestion rates and pharmacokinetic parameters, and impact on the association between perfluorooctanoate and preeclampsia in the C8 Health Project population.

PubMed

Avanasi, Raghavendhran; Shin, Hyeong-Moo; Vieira, Veronica M; Bartell, Scott M

2016-04-01

We recently utilized a suite of environmental fate and transport models and an integrated exposure and pharmacokinetic model to estimate individual perfluorooctanoate (PFOA) serum concentrations, and also assessed the association of those concentrations with preeclampsia for participants in the C8 Health Project (a cross-sectional study of over 69,000 people who were environmentally exposed to PFOA near a major U.S. fluoropolymer production facility located in West Virginia). However, the exposure estimates from this integrated model relied on default values for key independent exposure parameters including water ingestion rates, the serum PFOA half-life, and the volume of distribution for PFOA. The aim of the present study is to assess the impact of inter-individual variability and epistemic uncertainty in these parameters on the exposure estimates and subsequently, the epidemiological association between PFOA exposure and preeclampsia. We used Monte Carlo simulation to propagate inter-individual variability/epistemic uncertainty in the exposure assessment and reanalyzed the epidemiological association. Inter-individual variability in these parameters mildly impacted the serum PFOA concentration predictions (the lowest mean rank correlation between the estimated serum concentrations in our study and the original predicted serum concentrations was 0.95) and there was a negligible impact on the epidemiological association with preeclampsia (no change in the mean adjusted odds ratio (AOR) and the contribution of exposure uncertainty to the total uncertainty including sampling variability was 7%). However, when epistemic uncertainty was added along with the inter-individual variability, serum PFOA concentration predictions and their association with preeclampsia were moderately impacted (the mean AOR of preeclampsia occurrence was reduced from 1.12 to 1.09, and the contribution of exposure uncertainty to the total uncertainty was increased up to 33%). In conclusion, our study shows that the change of the rank exposure among the study participants due to variability and epistemic uncertainty in the independent exposure parameters was large enough to cause a 25% bias towards the null. This suggests that the true AOR of the association between PFOA and preeclampsia in this population might be higher than the originally reported AOR and has more uncertainty than indicated by the originally reported confidence interval. Copyright © 2016 Elsevier Inc. All rights reserved.

Aggregate exposure approaches for parabens in personal care products: a case assessment for children between 0 and 3 years old

PubMed Central

Gosens, Ilse; Delmaar, Christiaan J E; ter Burg, Wouter; de Heer, Cees; Schuur, A Gerlienke

2014-01-01

In the risk assessment of chemical substances, aggregation of exposure to a substance from different sources via different pathways is not common practice. Focusing the exposure assessment on a substance from a single source can lead to a significant underestimation of the risk. To gain more insight on how to perform an aggregate exposure assessment, we applied a deterministic (tier 1) and a person-oriented probabilistic approach (tier 2) for exposure to the four most common parabens through personal care products in children between 0 and 3 years old. Following a deterministic approach, a worst-case exposure estimate is calculated for methyl-, ethyl-, propyl- and butylparaben. As an illustration for risk assessment, Margins of Exposure (MoE) are calculated. These are 991 and 4966 for methyl- and ethylparaben, and 8 and 10 for propyl- and butylparaben, respectively. In tier 2, more detailed information on product use has been obtained from a small survey on product use of consumers. A probabilistic exposure assessment is performed to estimate the variability and uncertainty of exposure in a population. Results show that the internal exposure for each paraben is below the level determined in tier 1. However, for propyl- and butylparaben, the percentile of the population with an exposure probability above the assumed “safe” MoE of 100, is 13% and 7%, respectively. In conclusion, a tier 1 approach can be performed using simple equations and default point estimates, and serves as a starting point for exposure and risk assessment. If refinement is warranted, the more data demanding person-oriented probabilistic approach should be used. This probabilistic approach results in a more realistic exposure estimate, including the uncertainty, and allows determining the main drivers of exposure. Furthermore, it allows to estimate the percentage of the population for which the exposure is likely to be above a specific value. PMID:23801276

Spatial and Temporal Dynamics in Air Pollution Exposure Assessment

PubMed Central

Dias, Daniela; Tchepel, Oxana

2018-01-01

Analyzing individual exposure in urban areas offers several challenges where both the individual’s activities and air pollution levels demonstrate a large degree of spatial and temporal dynamics. This review article discusses the concepts, key elements, current developments in assessing personal exposure to urban air pollution (seventy-two studies reviewed) and respective advantages and disadvantages. A new conceptual structure to organize personal exposure assessment methods is proposed according to two classification criteria: (i) spatial-temporal variations of individuals’ activities (point-fixed or trajectory based) and (ii) characterization of air quality (variable or uniform). This review suggests that the spatial and temporal variability of urban air pollution levels in combination with indoor exposures and individual’s time-activity patterns are key elements of personal exposure assessment. In the literature review, the majority of revised studies (44 studies) indicate that the trajectory based with variable air quality approach provides a promising framework for tackling the important question of inter- and intra-variability of individual exposure. However, future quantitative comparison between the different approaches should be performed, and the selection of the most appropriate approach for exposure quantification should take into account the purpose of the health study. This review provides a structured basis for the intercomparing of different methodologies and to make their advantages and limitations more transparent in addressing specific research objectives. PMID:29558426

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

Knight, Stephen P, E-mail: stephen.knight@health.qld.gov.au

The aim of this review was to develop a radiographic optimisation strategy to make use of digital radiography (DR) and needle phosphor computerised radiography (CR) detectors, in order to lower radiation dose and improve image quality for paediatrics. This review was based on evidence-based practice, of which a component was a review of the relevant literature. The resulting exposure chart was developed with two distinct groups of exposure optimisation strategies – body exposures (for head, trunk, humerus, femur) and distal extremity exposures (elbow to finger, knee to toe). Exposure variables manipulated included kilovoltage peak (kVp), target detector exposure and milli-ampere-secondsmore » (mAs), automatic exposure control (AEC), additional beam filtration, and use of antiscatter grid. Mean dose area product (DAP) reductions of up to 83% for anterior–posterior (AP)/posterior–anterior (PA) abdomen projections were recorded postoptimisation due to manipulation of multiple-exposure variables. For body exposures, the target EI and detector exposure, and thus the required mAs were typically 20% less postoptimisation. Image quality for some distal extremity exposures was improved by lowering kVp and increasing mAs around constant entrance skin dose. It is recommended that purchasing digital X-ray equipment with high detective quantum efficiency detectors, and then optimising the exposure chart for use with these detectors is of high importance for sites performing paediatric imaging. Multiple-exposure variables may need to be manipulated to achieve optimal outcomes.« less

Joint nonparametric correction estimator for excess relative risk regression in survival analysis with exposure measurement error

PubMed Central

Wang, Ching-Yun; Cullings, Harry; Song, Xiao; Kopecky, Kenneth J.

2017-01-01

SUMMARY Observational epidemiological studies often confront the problem of estimating exposure-disease relationships when the exposure is not measured exactly. In the paper, we investigate exposure measurement error in excess relative risk regression, which is a widely used model in radiation exposure effect research. In the study cohort, a surrogate variable is available for the true unobserved exposure variable. The surrogate variable satisfies a generalized version of the classical additive measurement error model, but it may or may not have repeated measurements. In addition, an instrumental variable is available for individuals in a subset of the whole cohort. We develop a nonparametric correction (NPC) estimator using data from the subcohort, and further propose a joint nonparametric correction (JNPC) estimator using all observed data to adjust for exposure measurement error. An optimal linear combination estimator of JNPC and NPC is further developed. The proposed estimators are nonparametric, which are consistent without imposing a covariate or error distribution, and are robust to heteroscedastic errors. Finite sample performance is examined via a simulation study. We apply the developed methods to data from the Radiation Effects Research Foundation, in which chromosome aberration is used to adjust for the effects of radiation dose measurement error on the estimation of radiation dose responses. PMID:29354018

Tracking contributions to human body burden of environmental chemicals by correlating environmental measurements with biomarkers.

PubMed

Shin, Hyeong-Moo; McKone, Thomas E; Sohn, Michael D; Bennett, Deborah H

2014-01-01

The work addresses current knowledge gaps regarding causes for correlations between environmental and biomarker measurements and explores the underappreciated role of variability in disaggregating exposure attributes that contribute to biomarker levels. Our simulation-based study considers variability in environmental and food measurements, the relative contribution of various exposure sources (indoors and food), and the biological half-life of a compound, on the resulting correlations between biomarker and environmental measurements. For two hypothetical compounds whose half-lives are on the order of days for one and years for the other, we generate synthetic daily environmental concentrations and food exposures with different day-to-day and population variability as well as different amounts of home- and food-based exposure. Assuming that the total intake results only from home-based exposure and food ingestion, we estimate time-dependent biomarker concentrations using a one-compartment pharmacokinetic model. Box plots of modeled R2 values indicate that although the R2 correlation between wipe and biological (e.g., serum) measurements is within the same range for the two compounds, the relative contribution of the home exposure to the total exposure could differ by up to 20%, thus providing the relative indication of their contribution to body burden. The novel method introduced in this paper provides insights for evaluating scenarios or experiments where sample, exposure, and compound variability must be weighed in order to interpret associations between exposure data.

Promoting early exposure monitoring for respirable crystalline silica: Taking the laboratory to the mine site

PubMed Central

Cauda, Emanuele; Miller, Arthur; Drake, Pamela

2017-01-01

The exposure to respirable crystalline silica (RCS) in the mining industry is a recognized occupational hazard. The assessment and monitoring of the exposure to RCS is limited by two main factors: (1) variability of the silica percent in the mining dust and (2) lengthy off-site laboratory analysis of collected samples. The monitoring of respirable dust via traditional or real-time techniques is not adequate. A solution for on-site quantification of RCS in dust samples is being investigated by the Office of Mine Safety and Health Research, a division of the National Institute for Occupational Safety and Health. The use of portable Fourier transform infrared analyzers in conjunction with a direct-on-filter analysis approach is proposed. The progress made so far, the necessary steps in progress, and the application of the monitoring solution to a small data set is presented. When developed, the solution will allow operators to estimate RCS immediately after sampling, resulting in timelier monitoring of RCS for self-assessment of compliance at the end of the shift, more effective engineering monitoring, and better evaluation of control technologies. PMID:26558490

Brominated flame retardants and seafood safety: a review.

PubMed

Cruz, Rebeca; Cunha, Sara C; Casal, Susana

2015-04-01

Brominated flame retardants (BFRs), frequently applied to industrial and household products to make them less flammable, are highly persistent in the environment and cause multi-organ toxicity in human and wildlife. Based on the review of BFRs presence in seafood published from 2004 to 2014, it is clear that such pollutants are not ideally controlled as the surveys are too restricted, legislation inexistent for some classes, the analytical methodologies diversified, and several factors as food processing and eating habits are generally overlooked. Indeed, while a seafood rich diet presents plenty of nutritional benefits, it can also represent a potential source of these environmental contaminants. Since recent studies have shown that dietary intake constitutes a main route of human exposure to BFRs, it is of major importance to review and enhance these features, since seafood constitutes a chief pathway for human exposure and biomagnification of priority environmental contaminants. In particular, more objective studies focused on the variability factors behind contamination levels, and subsequent human exposure, are necessary to support the necessity for more restricted legislation worldwide. Copyright © 2015 Elsevier Ltd. All rights reserved.

Determinants of passive smoking in children in Edinburgh, Scotland.

PubMed Central

Jarvis, M J; Strachan, D P; Feyerabend, C

1992-01-01

OBJECTIVES. Using saliva cotinine as a quantitative marker, we examined the contribution of factors other than parental smoking to children's passive exposure to tobacco smoke. METHODS. Saliva specimens from a random sample of 734 7-year-old schoolchildren in Edinburgh, Scotland, were analyzed for cotinine. Their parents completed a questionnaire covering smoking habits and conditions in the home. RESULTS. A number of independent predictors of cotinine were identified in addition to the main one of smoking by household members. These predictors included home ownership, social class, day of the week, season of the year, number of parents present, crowding in the home, the number of children in the household, and sex. Cotinine was higher in children from less advantaged backgrounds, during winter, on Mondays, in girls, and when fewer other children were present. The effects were similar between children from nonsmoking and smoking homes. CONCLUSIONS. Questionnaire measures of parental smoking are insufficient to fully characterize young children's exposure to passive smoking. Because socioeconomic variables contribute to measured exposure, passive-smoking studies that treat class as a confounder and control for it may be overcontrolling. PMID:1503162

The risk of chronic traumatic brain injury in professional boxing: change in exposure variables over the past century

PubMed Central

Clausen, H; McCrory, P; Anderson, V; Fallon, K

2005-01-01

Objectives: To determine if boxing exposure has changed over time and hence if current professional boxers are at the same risk of developing chronic traumatic brain injury (CTBI) as historical controls. Design: Literature review of published studies and analysis of data of active professional boxers. Subjects: Professional boxers in the United Kingdom and Australia. Main outcome measures: Boxing history and participation in sparring and professional bouts. Results: Since the 1930s, the average duration of a professional boxer's career has dropped from 19 years to five years, and the mean number of career bouts has reduced from 336 to 13. This is despite no significant decline in participation rates from 1931 until 2002. Conclusions: The incidence of boxing related CTBI will diminish in the current era of professional boxing because of the reduction in exposure to repetitive head trauma and increasing medical monitoring of boxers, with preparticipation medical and neuroimaging assessments resulting in the detection of early and potentially pre-symptomatic cases of CTBI. PMID:16118306

Exposure and response prevention process predicts treatment outcome in youth with OCD.

PubMed

Kircanski, Katharina; Peris, Tara S

2015-04-01

Recent research on the treatment of adults with anxiety disorders suggests that aspects of the in-session exposure therapy process are relevant to clinical outcomes. However, few comprehensive studies have been conducted with children and adolescents. In the present study, 35 youth diagnosed with primary obsessive-compulsive disorder (OCD; M age = 12.9 years, 49% male, 63% Caucasian) completed 12 sessions of exposure and response prevention (ERP) in one of two treatment conditions as part of a pilot randomized controlled testing of a family focused intervention for OCD. Key exposure process variables, including youth self-reported distress during ERP and the quantity and quality of ERP completed, were computed. These variables were examined as predictors of treatment outcomes assessed at mid-treatment, post-treatment, and three-month follow-up, partialing treatment condition. In general, greater variability of distress during ERP and completing a greater proportion of combined exposures (i.e., exposures targeting more than one OC symptom at once) were predictive of better outcomes. Conversely, greater distress at the end of treatment was generally predictive of poorer outcomes. Finally, several variables, including within- and between-session decreases in distress during ERP, were not consistently predictive of outcomes. Findings signal potentially important facets of exposure for youth with OCD and have implications for treatment. A number of results also parallel recent findings in the adult literature, suggesting that there may be some continuity in exposure processes from child to adult development. Future work should examine additional measures of exposure process, such as psychophysiological arousal during exposure, in youth.

Environmental determinants of polycyclic aromatic hydrocarbons exposure at home, at kindergartens and during a commute.

PubMed

Miri, Mohammad; Alahabadi, Ahmad; Ehrampoush, Mohammad Hassan; Ghaffari, Hamid Reza; Sakhvidi, Mohammad Javad Zare; Eskandari, Mahboube; Rad, Abolfazl; Lotfi, Mohammad Hassan; Sheikhha, Mohammad Hassan

2018-06-11

The aim of this study was to assess the potential health risk of exposure to polycyclic aromatic hydrocarbons (PAHs) at home and kindergarten for pre-school children. The urine samples were taken from 200 pre-school children aged 5-7 years and analyzed for 1-OHP as a biomarker of PAHs. Mixed effect models were applied to investigate the association between effective environmental parameters (mode of transport, distance to major roads, traffic density, greenness, tobacco exposure, home ventilation, and grill foods) and urinary 1-OHP levels. A Monte-Carlo simulation technique was applied to calculate the risk of exposure to PAHs and to check the uncertainty of input variables and the sensitivity of the estimated risk. The median and inter quartile range (IQR) of 1-OHP was 257 (188.5) ng L -1 . There was a positive significant association between distance from the kindergartens to the green space with surface area ≥5000 m 2 and 1-OHP concentration (β = 0.844, 95% CI: 0.223, 1.46, P-value = 0.009). Also, urinary 1-OHP was found to be inversely associated with the time the window was open at the home (β = -12.56, 95% CI: -23.52, -1.596, P-value = 0.025) and normalized difference vegetation index (NDVI) in a 100 m buffer around the homes. The mean (9.76 E-3) and 95th percentile (3.28 E-2) of the hazard quotient (HQ) indicated that the concentration of urinary 1-OHP is at a safe level for the target population (HQ < 1). According to the sensitivity analysis results, the concentration of 1-OHP is the most influential variable in the estimated risk. Our findings indicated that the proximity of homes and kindergartens to green space areas and their remoteness from the main streets and heavy traffic areas are associated with reduced exposure to PAHs. Copyright © 2018 Elsevier Ltd. All rights reserved.

The individualistic fallacy, ecological studies and instrumental variables: a causal interpretation.

PubMed

Loney, Tom; Nagelkerke, Nico J

2014-01-01

The validity of ecological studies in epidemiology for inferring causal relationships has been widely challenged as observed associations could be biased by the Ecological Fallacy. We reconsider the important design components of ecological studies, and discuss the conditions that may lead to spurious associations. Ecological associations are useful and valid when the ecological exposures can be interpreted as Instrumental Variables. A suitable example may be a time series analysis of environmental pollution (e.g. particulate matter with an aerodynamic diameter of <10 micrometres; PM10) and health outcomes (e.g. hospital admissions for acute myocardial infarction) as environmental pollution levels are a cause of individual exposure levels and not just an aggregate measurement. Ecological exposures may also be employed in situations (perhaps rare) where individual exposures are known but their associations with health outcomes are confounded by unknown or unquantifiable factors. Ecological associations have a notorious reputation in epidemiology and individualistic associations are considered superior to ecological associations because of the "ecological fallacy". We have argued that this is incorrect in situations in which ecological or aggregate exposures can serve as an instrumental variable and associations between individual exposure and outcome are likely to be confounded by unmeasured variables.

Sample size requirements for indirect association studies of gene-environment interactions (G x E).

PubMed

Hein, Rebecca; Beckmann, Lars; Chang-Claude, Jenny

2008-04-01

Association studies accounting for gene-environment interactions (G x E) may be useful for detecting genetic effects. Although current technology enables very dense marker spacing in genetic association studies, the true disease variants may not be genotyped. Thus, causal genes are searched for by indirect association using genetic markers in linkage disequilibrium (LD) with the true disease variants. Sample sizes needed to detect G x E effects in indirect case-control association studies depend on the true genetic main effects, disease allele frequencies, whether marker and disease allele frequencies match, LD between loci, main effects and prevalence of environmental exposures, and the magnitude of interactions. We explored variables influencing sample sizes needed to detect G x E, compared these sample sizes with those required to detect genetic marginal effects, and provide an algorithm for power and sample size estimations. Required sample sizes may be heavily inflated if LD between marker and disease loci decreases. More than 10,000 case-control pairs may be required to detect G x E. However, given weak true genetic main effects, moderate prevalence of environmental exposures, as well as strong interactions, G x E effects may be detected with smaller sample sizes than those needed for the detection of genetic marginal effects. Moreover, in this scenario, rare disease variants may only be detectable when G x E is included in the analyses. Thus, the analysis of G x E appears to be an attractive option for the detection of weak genetic main effects of rare variants that may not be detectable in the analysis of genetic marginal effects only.

Robust best linear estimator for Cox regression with instrumental variables in whole cohort and surrogates with additive measurement error in calibration sample.

PubMed

Wang, Ching-Yun; Song, Xiao

2016-11-01

Biomedical researchers are often interested in estimating the effect of an environmental exposure in relation to a chronic disease endpoint. However, the exposure variable of interest may be measured with errors. In a subset of the whole cohort, a surrogate variable is available for the true unobserved exposure variable. The surrogate variable satisfies an additive measurement error model, but it may not have repeated measurements. The subset in which the surrogate variables are available is called a calibration sample. In addition to the surrogate variables that are available among the subjects in the calibration sample, we consider the situation when there is an instrumental variable available for all study subjects. An instrumental variable is correlated with the unobserved true exposure variable, and hence can be useful in the estimation of the regression coefficients. In this paper, we propose a nonparametric method for Cox regression using the observed data from the whole cohort. The nonparametric estimator is the best linear combination of a nonparametric correction estimator from the calibration sample and the difference of the naive estimators from the calibration sample and the whole cohort. The asymptotic distribution is derived, and the finite sample performance of the proposed estimator is examined via intensive simulation studies. The methods are applied to the Nutritional Biomarkers Study of the Women's Health Initiative. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Occurrence and multivariate exploratory analysis of the natural radioactivity anomaly in the south coastal region of Kenya

NASA Astrophysics Data System (ADS)

Kaniu, M. I.; Angeyo, K. H.; Darby, I. G.

2018-05-01

Characterized by a variety of rock formations, namely alkaline, igneous and sedimentary that contain significant deposits of monazite and pyrochlore ores, the south coastal region of Kenya may be regarded as highly heterogeneous with regard to its geochemistry, mineralogy as well as geological morphology. The region is one of the several alkaline carbonatite complexes of Kenya that are associated with high natural background radiation and therefore radioactivity anomaly. However, this high background radiation (HBR) anomaly has hardly been systematically assessed and delineated with regard to the spatial, geological, geochemical as well as anthropogenic variability and co-dependencies. We conducted wide-ranging in-situ gamma-ray spectrometric measurements in this area. The goal of the study was to assess the radiation exposure as well as determine the underlying natural radioactivity levels in the region. In this paper we report the occurrence, exploratory analysis and modeling to assess the multivariate geo-dependence and spatial variability of the radioactivity and associated radiation exposure. Unsupervised principal component analysis and ternary plots were utilized in the study. It was observed that areas which exhibit HBR anomalies are located along the south coast paved road and in the Mrima-Kiruku complex. These areas showed a trend towards enhanced levels of 232Th and 238U and low 40K. The spatial variability of the radioactivity anomaly was found to be mainly constrained by anthropogenic activities, underlying geology and geochemical processes in the terrestrial environment.

Exposure to wood smoke increases arterial stiffness and decreases heart rate variability in humans

PubMed Central

2013-01-01

Background Emissions from biomass combustion are a major source of indoor and outdoor air pollution, and are estimated to cause millions of premature deaths worldwide annually. Whilst adverse respiratory health effects of biomass exposure are well established, less is known about its effects on the cardiovascular system. In this study we assessed the effect of exposure to wood smoke on heart rate, blood pressure, central arterial stiffness and heart rate variability in otherwise healthy persons. Methods Fourteen healthy non-smoking subjects participated in a randomized, double-blind crossover study. Subjects were exposed to dilute wood smoke (mean particle concentration of 314±38 μg/m3) or filtered air for three hours during intermittent exercise. Heart rate, blood pressure, central arterial stiffness and heart rate variability were measured at baseline and for one hour post-exposure. Results Central arterial stiffness, measured as augmentation index, augmentation pressure and pulse wave velocity, was higher after wood smoke exposure as compared to filtered air (p < 0.01 for all), and heart rate was increased (p < 0.01) although there was no effect on blood pressure. Heart rate variability (SDNN, RMSSD and pNN50; p = 0.003, p < 0.001 and p < 0.001 respectively) was decreased one hour following exposure to wood smoke compared to filtered air. Conclusions Acute exposure to wood smoke as a model of exposure to biomass combustion is associated with an immediate increase in central arterial stiffness and a simultaneous reduction in heart rate variability. As biomass is used for cooking and heating by a large fraction of the global population and is currently advocated as a sustainable alternative energy source, further studies are required to establish its likely impact on cardiovascular disease. Trial registration ClinicalTrials.gov, NCT01488500 PMID:23742058

Mendelian randomization analysis of a time-varying exposure for binary disease outcomes using functional data analysis methods.

PubMed

Cao, Ying; Rajan, Suja S; Wei, Peng

2016-12-01

A Mendelian randomization (MR) analysis is performed to analyze the causal effect of an exposure variable on a disease outcome in observational studies, by using genetic variants that affect the disease outcome only through the exposure variable. This method has recently gained popularity among epidemiologists given the success of genetic association studies. Many exposure variables of interest in epidemiological studies are time varying, for example, body mass index (BMI). Although longitudinal data have been collected in many cohort studies, current MR studies only use one measurement of a time-varying exposure variable, which cannot adequately capture the long-term time-varying information. We propose using the functional principal component analysis method to recover the underlying individual trajectory of the time-varying exposure from the sparsely and irregularly observed longitudinal data, and then conduct MR analysis using the recovered curves. We further propose two MR analysis methods. The first assumes a cumulative effect of the time-varying exposure variable on the disease risk, while the second assumes a time-varying genetic effect and employs functional regression models. We focus on statistical testing for a causal effect. Our simulation studies mimicking the real data show that the proposed functional data analysis based methods incorporating longitudinal data have substantial power gains compared to standard MR analysis using only one measurement. We used the Framingham Heart Study data to demonstrate the promising performance of the new methods as well as inconsistent results produced by the standard MR analysis that relies on a single measurement of the exposure at some arbitrary time point. © 2016 WILEY PERIODICALS, INC.

Global Gradients of Coral Exposure to Environmental Stresses and Implications for Local Management

PubMed Central

Maina, Joseph; McClanahan, Tim R.; Venus, Valentijn; Ateweberhan, Mebrahtu; Madin, Joshua

2011-01-01

Background The decline of coral reefs globally underscores the need for a spatial assessment of their exposure to multiple environmental stressors to estimate vulnerability and evaluate potential counter-measures. Methodology/Principal Findings This study combined global spatial gradients of coral exposure to radiation stress factors (temperature, UV light and doldrums), stress-reinforcing factors (sedimentation and eutrophication), and stress-reducing factors (temperature variability and tidal amplitude) to produce a global map of coral exposure and identify areas where exposure depends on factors that can be locally managed. A systems analytical approach was used to define interactions between radiation stress variables, stress reinforcing variables and stress reducing variables. Fuzzy logic and spatial ordinations were employed to quantify coral exposure to these stressors. Globally, corals are exposed to radiation and reinforcing stress, albeit with high spatial variability within regions. Based on ordination of exposure grades, regions group into two clusters. The first cluster was composed of severely exposed regions with high radiation and low reducing stress scores (South East Asia, Micronesia, Eastern Pacific and the central Indian Ocean) or alternatively high reinforcing stress scores (the Middle East and the Western Australia). The second cluster was composed of moderately to highly exposed regions with moderate to high scores in both radiation and reducing factors (Caribbean, Great Barrier Reef (GBR), Central Pacific, Polynesia and the western Indian Ocean) where the GBR was strongly associated with reinforcing stress. Conclusions/Significance Despite radiation stress being the most dominant stressor, the exposure of coral reefs could be reduced by locally managing chronic human impacts that act to reinforce radiation stress. Future research and management efforts should focus on incorporating the factors that mitigate the effect of coral stressors until long-term carbon reductions are achieved through global negotiations. PMID:21860667

Spatio-seasonal variability of chromophoric dissolved organic matter absorption and responses to photobleaching in a large shallow temperate lake

NASA Astrophysics Data System (ADS)

Encina Aulló-Maestro, María; Hunter, Peter; Spyrakos, Evangelos; Mercatoris, Pierre; Kovács, Attila; Horváth, Hajnalka; Preston, Tom; Présing, Mátyás; Torres Palenzuela, Jesús; Tyler, Andrew

2017-03-01

The development and validation of remote-sensing-based approaches for the retrieval of chromophoric dissolved organic matter (CDOM) concentrations requires a comprehensive understanding of the sources and magnitude of variability in the optical properties of dissolved material within lakes. In this study, spatial and seasonal variability in concentration and composition of CDOM and the origin of its variation was studied in Lake Balaton (Hungary), a large temperate shallow lake in central Europe. In addition, we investigated the effect of photobleaching on the optical properties of CDOM through in-lake incubation experiments. There was marked variability throughout the year in CDOM absorption in Lake Balaton (aCDOM(440) = 0. 06-9.01 m-1). The highest values were consistently observed at the mouth of the main inflow (Zala River), which drains humic-rich material from the adjoining Kis-Balaton wetland, but CDOM absorption decreased rapidly towards the east where it was consistently lower and less variable than in the westernmost lake basins. The spectral slope parameter for the interval of 350-500 nm (SCDOM(350-500)) was more variable with increasing distance from the inflow (observed range 0.0161-0.0181 nm-1 for the mouth of the main inflow and 0.0158-0.0300 nm-1 for waters closer to the outflow). However, spatial variation in SCDOM was more constant exhibiting a negative correlation with aCDOM(440). Dissolved organic carbon (DOC) was strongly positively correlated with aCDOM(440) and followed a similar seasonal trend but it demonstrated more variability than either aCDOM or SCDOM with distance through the system. Photobleaching resulting from a 7-day exposure to natural solar UV radiation resulted in a marked decrease in allochthonous CDOM absorption (7.04 to 3.36 m-1, 42 % decrease). Photodegradation also resulted in an increase in the spectral slope coefficient of dissolved material.

THE COMPETITION BETWEEN METHYLMERCURY RISKS AND OMEGA-3 POLYUNSATURATED FATTY ACID BENEFITS: A REVIEW OF CONFLICTING EVIDENCE ON FISH CONSUMPTION AND CARDIOVASCULAR HEALTH.

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

LIPFERT, F.W.; SULLIVAN, T.M.

2006-10-31

The health concerns of methylmercury (MeHg) contamination of seafood have recently been extended to include cardiovascular effects, especially premature mortality. Although the fatty acids (fish oils) found in most species are thought to confer a wide range of health benefits, especially to the cardiovascular system, some epidemiological studies have suggested that such benefits may be offset by adverse effects of MeHg. This comprehensive review is based on searches of the NIH MEDLINE database and compares and contrasts 145 published studies involving cardiovascular effects and exposures to mercury and other fish contaminants, intake of fatty acids including dietary supplements of fishmore » oils, and rates of seafood consumption. Since few of these studies include adequate simultaneous measurements of all of these potential predictor variables, we summarized their effects separately, across the available studies of each, and then drew conclusions based on the aggregated findings. It is important to realize that studies of seafood consumption encompass the net effects of all of these predictor variables, but that seafood intake studies are rarely supported by human biomarker measurements that reflect the actual uptake of harmful as well as beneficial fish ingredients. As a result, exposure measurement error is an issue when comparing studies and predictor variables. It is also possible that the observed benefits of eating fish may relate more to the characteristics of the consumers than to those of the fish. We found the evidence for adverse cardiovascular effects of MeHg to be sparse and unconvincing. Studies of cardiovascular mortality show net benefits, and the findings of adverse effects are mainly limited to studies Finland at high mercury exposure levels. By contrast, a very consistent picture of beneficial effects is seen for fatty acids, after recognizing the effects of exposure uncertainties and the presence of threshold effects. Studies based on measured biomarker levels are seen to be the most reliable and present a convincing picture of strong beneficial effects, especially for those causes of death involving cardiac arrhythmia. This conclusion also extends to studies of fish-oil supplementation. Studies based on fish consumption show mainly benefits from increased consumption. This finding is supported by an ecological study at the national population level, for which the lifestyle effects that might be correlated with fish consumption within a given population would be expected to ''average out'' across nations. Finally, the net survival benefits resulting from eating fish are consistent with studies involving complete diets, although benefits are also seen to accrue from reduced consumption of red meat and saturated fats.« less

Spatial variability of the effect of air pollution on term birth weight: evaluating influential factors using Bayesian hierarchical models.

PubMed

Li, Lianfa; Laurent, Olivier; Wu, Jun

2016-02-05

Epidemiological studies suggest that air pollution is adversely associated with pregnancy outcomes. Such associations may be modified by spatially-varying factors including socio-demographic characteristics, land-use patterns and unaccounted exposures. Yet, few studies have systematically investigated the impact of these factors on spatial variability of the air pollution's effects. This study aimed to examine spatial variability of the effects of air pollution on term birth weight across Census tracts and the influence of tract-level factors on such variability. We obtained over 900,000 birth records from 2001 to 2008 in Los Angeles County, California, USA. Air pollution exposure was modeled at individual level for nitrogen dioxide (NO2) and nitrogen oxides (NOx) using spatiotemporal models. Two-stage Bayesian hierarchical non-linear models were developed to (1) quantify the associations between air pollution exposure and term birth weight within each tract; and (2) examine the socio-demographic, land-use, and exposure-related factors contributing to the between-tract variability of the associations between air pollution and term birth weight. Higher air pollution exposure was associated with lower term birth weight (average posterior effects: -14.7 (95 % CI: -19.8, -9.7) g per 10 ppb increment in NO2 and -6.9 (95 % CI: -12.9, -0.9) g per 10 ppb increment in NOx). The variation of the association across Census tracts was significantly influenced by the tract-level socio-demographic, exposure-related and land-use factors. Our models captured the complex non-linear relationship between these factors and the associations between air pollution and term birth weight: we observed the thresholds from which the influence of the tract-level factors was markedly exacerbated or attenuated. Exacerbating factors might reflect additional exposure to environmental insults or lower socio-economic status with higher vulnerability, whereas attenuating factors might indicate reduced exposure or higher socioeconomic status with lower vulnerability. Our Bayesian models effectively combined a priori knowledge with training data to infer the posterior association of air pollution with term birth weight and to evaluate the influence of the tract-level factors on spatial variability of such association. This study contributes new findings about non-linear influences of socio-demographic factors, land-use patterns, and unaccounted exposures on spatial variability of the effects of air pollution.

Knowledge, attitude and practice regarding solar ultraviolet exposure among medical university students in Northeast China.

PubMed

Gao, Qian; Liu, Guangcong; Liu, Yang

2014-11-01

To assess the knowledge, attitudes and practices regarding the health effects of ultraviolet radiation (UVR) and sun exposure among medical university students in Northeast China, 385 subjects were investigated on October 2013 using a self-administered multiple-choice questionnaire. Most of the subjects knew the effects of UVR on skin cancer (95.6%) and sunburn (92.2%), but fewer knew of the eye damage that can result from UVR (27.8% cataract and 3.1% pterygium). Correspondingly, the main purpose of adopting sun protection was considered to be 'preventing sunburn' (55.4%), but 'preventing eye damage' was the least (1.8%). In actual behaviour, the eyes received the least protection as well. Although knowing the effects of UVR on vitamin D synthesis (87.3%), 66.8% of participants never or seldom increased sun exposure. Compared to men, women were more likely to reduce sun exposure (P<0.001). Only a small fraction of subjects (6.6%) thought that tanning was attractive. Considering the response variability to UVR in people with different skin colours, different sun protection programs should be provided. In China, especially in the North, the public should be educated to moderately increase sun exposure to maintain adequate vitamin D status while also protecting against eye damage from UVR. Copyright © 2014 Elsevier B.V. All rights reserved.

Do socioeconomic characteristics modify the short term association between air pollution and mortality? Evidence from a zonal time series in Hamilton, Canada

PubMed Central

Jerrett, M; Burnett, R; Brook, J; Kanaroglou, P; Giovis, C; Finkelstein, N; Hutchison, B

2004-01-01

Study objective: To assess the short term association between air pollution and mortality in different zones of an industrial city. An intra-urban study design is used to test the hypothesis that socioeconomic characteristics modify the acute health effects of ambient air pollution exposure. Design: The City of Hamilton, Canada, was divided into five zones based on proximity to fixed site air pollution monitors. Within each zone, daily counts of non-trauma mortality and air pollution estimates were combined. Generalised linear models (GLMs) were used to test mortality associations with sulphur dioxide (SO2) and with particulate air pollution measured by the coefficient of haze (CoH). Main results: Increased mortality was associated with air pollution exposure in a citywide model and in intra-urban zones with lower socioeconomic characteristics. Low educational attainment and high manufacturing employment in the zones significantly and positively modified the acute mortality effects of air pollution exposure. Discussion: Three possible explanations are proposed for the observed effect modification by education and manufacturing: (1) those in manufacturing receive higher workplace exposures that combine with ambient exposures to produce larger health effects; (2) persons with lower education are less mobile and experience less exposure measurement error, which reduces bias toward the null; or (3) manufacturing and education proxy for many social variables representing material deprivation, and poor material conditions increase susceptibility to health risks from air pollution. PMID:14684724

Sequential screening for psychosocial and behavioral risk during pregnancy in a population of urban African-Americans

PubMed Central

Kiely, Michele; Gantz, Marie G.; El-Khorazaty, M. Nabil; El-Mohandes, Ayman AE

2013-01-01

Objective Screening for psychosocial and behavioral risks, such as depression, intimate partner violence and smoking, during pregnancy is considered state-of-the-art in prenatal care. This prospective longitudinal analysis examines the added benefit of repeated screening over a one-time screen in identifying such risks during pregnancy. Design Data were collected as part of a randomized controlled trial to address intimate partner violence, depression, smoking and environmental tobacco smoke exposure in African-Americans women. Setting PNC sites in the District of Columbia serving mainly minority women Population 1044 African-American pregnant women in the District of Columbia Methods Mothers were classified by their initial response (acknowledgement of risks) and updated during pregnancy. Risks were considered new if they were not previously reported. Standard hypothesis tests and logistic regression were used to predict acknowledgment of any new risk(s) during pregnancy. Main Outcome Measures New risks; psychosocial variables to understand what factors might help identify acknowledgement of additional risk(s). Results Repeated screening identified more mothers acknowledging risk over time. Reported smoking increased by 11%, environmental tobacco smoke exposure by 19%, intimate partner violence by 9%, and depression by 20%. The psychosocial variables collected at the baseline that were entered into the logistic regression model included relationship status, education, Medicaid, illicit drug use, and alcohol use during pregnancy. Among these, only education less than high school was associated in acknowledgement of new risk in the bivariate analyses and significantly predicted identification of new risks (OR=1.39, 95%CI, 1.01-1.90). Conclusions It is difficult early on to predict who will acknowledge new risks over the course of pregnancy, thus all women should be screened repeatedly to allow identification and intervention during prenatal care. PMID:23906260

Temporal and Spatial Simulation of Atmospheric Pollutant PM2.5 Changes and Risk Assessment of Population Exposure to Pollution Using Optimization Algorithms of the Back Propagation-Artificial Neural Network Model and GIS

PubMed Central

Zhang, Ping; Hong, Bo; He, Liang; Cheng, Fei; Zhao, Peng; Wei, Cailiang; Liu, Yunhui

2015-01-01

PM2.5 pollution has become of increasing public concern because of its relative importance and sensitivity to population health risks. Accurate predictions of PM2.5 pollution and population exposure risks are crucial to developing effective air pollution control strategies. We simulated and predicted the temporal and spatial changes of PM2.5 concentration and population exposure risks, by coupling optimization algorithms of the Back Propagation-Artificial Neural Network (BP-ANN) model and a geographical information system (GIS) in Xi’an, China, for 2013, 2020, and 2025. Results indicated that PM2.5 concentration was positively correlated with GDP, SO2, and NO2, while it was negatively correlated with population density, average temperature, precipitation, and wind speed. Principal component analysis of the PM2.5 concentration and its influencing factors’ variables extracted four components that accounted for 86.39% of the total variance. Correlation coefficients of the Levenberg-Marquardt (trainlm) and elastic (trainrp) algorithms were more than 0.8, the index of agreement (IA) ranged from 0.541 to 0.863 and from 0.502 to 0.803 by trainrp and trainlm algorithms, respectively; mean bias error (MBE) and Root Mean Square Error (RMSE) indicated that the predicted values were very close to the observed values, and the accuracy of trainlm algorithm was better than the trainrp. Compared to 2013, temporal and spatial variation of PM2.5 concentration and risk of population exposure to pollution decreased in 2020 and 2025. The high-risk areas of population exposure to PM2.5 were mainly distributed in the northern region, where there is downtown traffic, abundant commercial activity, and more exhaust emissions. A moderate risk zone was located in the southern region associated with some industrial pollution sources, and there were mainly low-risk areas in the western and eastern regions, which are predominantly residential and educational areas. PMID:26426030

Temporal and Spatial Simulation of Atmospheric Pollutant PM2.5 Changes and Risk Assessment of Population Exposure to Pollution Using Optimization Algorithms of the Back Propagation-Artificial Neural Network Model and GIS.

PubMed

Zhang, Ping; Hong, Bo; He, Liang; Cheng, Fei; Zhao, Peng; Wei, Cailiang; Liu, Yunhui

2015-09-29

PM2.5 pollution has become of increasing public concern because of its relative importance and sensitivity to population health risks. Accurate predictions of PM2.5 pollution and population exposure risks are crucial to developing effective air pollution control strategies. We simulated and predicted the temporal and spatial changes of PM2.5 concentration and population exposure risks, by coupling optimization algorithms of the Back Propagation-Artificial Neural Network (BP-ANN) model and a geographical information system (GIS) in Xi'an, China, for 2013, 2020, and 2025. Results indicated that PM2.5 concentration was positively correlated with GDP, SO₂, and NO₂, while it was negatively correlated with population density, average temperature, precipitation, and wind speed. Principal component analysis of the PM2.5 concentration and its influencing factors' variables extracted four components that accounted for 86.39% of the total variance. Correlation coefficients of the Levenberg-Marquardt (trainlm) and elastic (trainrp) algorithms were more than 0.8, the index of agreement (IA) ranged from 0.541 to 0.863 and from 0.502 to 0.803 by trainrp and trainlm algorithms, respectively; mean bias error (MBE) and Root Mean Square Error (RMSE) indicated that the predicted values were very close to the observed values, and the accuracy of trainlm algorithm was better than the trainrp. Compared to 2013, temporal and spatial variation of PM2.5 concentration and risk of population exposure to pollution decreased in 2020 and 2025. The high-risk areas of population exposure to PM2.5 were mainly distributed in the northern region, where there is downtown traffic, abundant commercial activity, and more exhaust emissions. A moderate risk zone was located in the southern region associated with some industrial pollution sources, and there were mainly low-risk areas in the western and eastern regions, which are predominantly residential and educational areas.

Intra- and interlaboratory variability in acute toxicity tests with glochidia and juveniles of freshwater mussels (Unionidae)

USGS Publications Warehouse

Wang, N.; Augspurger, T.; Barnhart, M.C.; Bidwell, Joseph R.; Cope, W.G.; Dwyer, F.J.; Geis, S.; Greer, I.E.; Ingersoll, C.G.; Kane, C.M.; May, T.W.; Neves, R.J.; Newton, T.J.; Roberts, A.D.; Whites, D.W.

2007-01-01

The present study evaluated the performance and variability in acute toxicity tests with glochidia and newly transformed juvenile mussels using the standard methods outlined in American Society for Testing and Materials (ASTM). Multiple 48-h toxicity tests with glochidia and 96-h tests with juvenile mussels were conducted within a single laboratory and among five laboratories. All tests met the test acceptability requirements (e.g., ???90% control survival). Intralaboratory tests were conducted over two consecutive mussel-spawning seasons with mucket (Actinonaias ligamentina) or fatmucket (Lampsilis siliquoidea) using copper, ammonia, or chlorine as a toxicant. For the glochidia of both species, the variability of intralaboratory median effective concentrations (EC50s) for the three toxicants, expressed as the coefficient of variation (CV), ranged from 14 to 27% in 24-h exposures and from 13 to 36% in 48-h exposures. The intralaboratory CV of copper EC50s for juvenile fatmucket was 24% in 48-h exposures and 13% in 96-h exposures. Interlaboratory tests were conducted with fatmucket glochidia and juveniles by five laboratories using copper as a toxicant. The interlaboratory CV of copper EC50s for glochidia was 13% in 24-h exposures and 24% in 48-h exposures, and the interlaboratory CV for juveniles was 22% in 48-h exposures and 42% in 96-h exposures. The high completion success and the overall low variability in test results indicate that the test methods have acceptable precision and can be performed routinely. ?? 2007 SETAC.

Exposure Estimation and Interpretation of Occupational Risk: Enhanced Information for the Occupational Risk Manager

PubMed Central

Waters, Martha; McKernan, Lauralynn; Maier, Andrew; Jayjock, Michael; Schaeffer, Val; Brosseau, Lisa

2015-01-01

The fundamental goal of this article is to describe, define, and analyze the components of the risk characterization process for occupational exposures. Current methods are described for the probabilistic characterization of exposure, including newer techniques that have increasing applications for assessing data from occupational exposure scenarios. In addition, since the probability of health effects reflects variability in the exposure estimate as well as the dose-response curve—the integrated considerations of variability surrounding both components of the risk characterization provide greater information to the occupational hygienist. Probabilistic tools provide a more informed view of exposure as compared to use of discrete point estimates for these inputs to the risk characterization process. Active use of such tools for exposure and risk assessment will lead to a scientifically supported worker health protection program. Understanding the bases for an occupational risk assessment, focusing on important sources of variability and uncertainty enables characterizing occupational risk in terms of a probability, rather than a binary decision of acceptable risk or unacceptable risk. A critical review of existing methods highlights several conclusions: (1) exposure estimates and the dose-response are impacted by both variability and uncertainty and a well-developed risk characterization reflects and communicates this consideration; (2) occupational risk is probabilistic in nature and most accurately considered as a distribution, not a point estimate; and (3) occupational hygienists have a variety of tools available to incorporate concepts of risk characterization into occupational health and practice. PMID:26302336

Airborne asbestos exposures associated with gasket and packing replacement: a simulation study of flange and valve repair work and an assessment of exposure variables.

PubMed

Madl, Amy K; Devlin, Kathryn D; Perez, Angela L; Hollins, Dana M; Cowan, Dallas M; Scott, Paul K; White, Katherine; Cheng, Thales J; Henshaw, John L

2015-02-01

A simulation study was conducted to evaluate worker and area exposure to airborne asbestos associated with the replacement of asbestos-containing gaskets and packing materials from flanges and valves and assess the influence of several variables previously not investigated. Additionally, potential of take home exposures from clothing worn during the study was characterized. Our data showed that product type, ventilation type, gasket location, flange or bonnet size, number of flanges involved, surface characteristics, gasket surface adherence, and even activity type did not have a significant effect on worker exposures. Average worker asbestos exposures during flange gasket work (PCME=0.166 f/cc, 12-59 min) were similar to average worker asbestos exposures during valve overhaul work (PCME=0.165 f/cc, 7-76 min). Average 8-h TWA asbestos exposures were estimated to range from 0.010 to 0.062 f/cc. Handling clothes worn during gasket and packing replacement activities demonstrated exposures that were 0.71% (0.0009 f/cc 40-h TWA) of the airborne asbestos concentration experienced during the 5 days of the study. Despite the many variables considered in this study, exposures during gasket and packing replacement occur within a relatively narrow range, are below current and historical occupational exposure limits for asbestos, and are consistent with previously published data. Copyright © 2014 Elsevier Inc. All rights reserved.

Variability in prefrontal hemodynamic response during exposure to repeated self-selected music excerpts, a near-infrared spectroscopy study.

PubMed

Moghimi, Saba; Schudlo, Larissa; Chau, Tom; Guerguerian, Anne-Marie

2015-01-01

Music-induced brain activity modulations in areas involved in emotion regulation may be useful in achieving therapeutic outcomes. Clinical applications of music may involve prolonged or repeated exposures to music. However, the variability of the observed brain activity patterns in repeated exposures to music is not well understood. We hypothesized that multiple exposures to the same music would elicit more consistent activity patterns than exposure to different music. In this study, the temporal and spatial variability of cerebral prefrontal hemodynamic response was investigated across multiple exposures to self-selected musical excerpts in 10 healthy adults. The hemodynamic changes were measured using prefrontal cortex near infrared spectroscopy and represented by instantaneous phase values. Based on spatial and temporal characteristics of these observed hemodynamic changes, we defined a consistency index to represent variability across these domains. The consistency index across repeated exposures to the same piece of music was compared to the consistency index corresponding to prefrontal activity from randomly matched non-identical musical excerpts. Consistency indexes were significantly different for identical versus non-identical musical excerpts when comparing a subset of repetitions. When all four exposures were compared, no significant difference was observed between the consistency indexes of randomly matched non-identical musical excerpts and the consistency index corresponding to repetitions of the same musical excerpts. This observation suggests the existence of only partial consistency between repeated exposures to the same musical excerpt, which may stem from the role of the prefrontal cortex in regulating other cognitive and emotional processes.

Variability in Prefrontal Hemodynamic Response during Exposure to Repeated Self-Selected Music Excerpts, a Near-Infrared Spectroscopy Study

PubMed Central

Moghimi, Saba; Schudlo, Larissa; Chau, Tom; Guerguerian, Anne-Marie

2015-01-01

Music-induced brain activity modulations in areas involved in emotion regulation may be useful in achieving therapeutic outcomes. Clinical applications of music may involve prolonged or repeated exposures to music. However, the variability of the observed brain activity patterns in repeated exposures to music is not well understood. We hypothesized that multiple exposures to the same music would elicit more consistent activity patterns than exposure to different music. In this study, the temporal and spatial variability of cerebral prefrontal hemodynamic response was investigated across multiple exposures to self-selected musical excerpts in 10 healthy adults. The hemodynamic changes were measured using prefrontal cortex near infrared spectroscopy and represented by instantaneous phase values. Based on spatial and temporal characteristics of these observed hemodynamic changes, we defined a consistency index to represent variability across these domains. The consistency index across repeated exposures to the same piece of music was compared to the consistency index corresponding to prefrontal activity from randomly matched non-identical musical excerpts. Consistency indexes were significantly different for identical versus non-identical musical excerpts when comparing a subset of repetitions. When all four exposures were compared, no significant difference was observed between the consistency indexes of randomly matched non-identical musical excerpts and the consistency index corresponding to repetitions of the same musical excerpts. This observation suggests the existence of only partial consistency between repeated exposures to the same musical excerpt, which may stem from the role of the prefrontal cortex in regulating other cognitive and emotional processes. PMID:25837268

The Association Between School Bonding and Smoking Amongst Chilean Adolescents.

PubMed

Gaete, Jorge; Montgomery, Alan; Araya, Ricardo

2015-01-01

The objective of the research was to study the association between school bonding dimensions (school commitment and school attachment) and current adolescent smoking in Chile, controlling for confounding variables using the fifth Chilean School Population National Substance Use Survey, 2003 (CHSS-2003) data set. The CHSS-2003 is a stratified cross-sectional survey that gathers information about personal, familial, peer, and school factors and cigarette use using a self-reported questionnaire. Complete data from 21,956 adolescent students for all the variables of interest were used in the analyses. An exploratory factor analysis (EFA) was performed in order to explore the construct validity of the questionnaire and create the main exposure and potential confounding variables. Multivariable logistic regression analyses were undertaken to study the association between school bonding and smoking. The construct validity of the school attachment and school commitment scales was mainly supported by the EFA. Multivariable analyses showed strong evidence that, after adjusting for factors from different domains, school commitment (student's good grades and school attendance) appears to have a clear inverse association with current smoking (odds ratio [OR]=0.46, 95% confidence interval [CI]: 0.38-0.56). On the other hand, school attachment (their feelings towards their school and their teachers) was not associated with adolescent smoking (OR=1.16, 95% CI: 0.88-1.53). School commitment was strongly associated with current smoking. It is important to further study this variable with the aim of ascertaining whether or not interventions that improve school commitment may prevent or reduce smoking amongst adolescent students.

Respiratory symptoms as health status indicators in workers at ceramics manufacturing facilities.

PubMed

Rondon, Edilaura Nunes; Silva, Regina Maria Veras Gonçalves da; Botelho, Clovis

2011-01-01

To assess the prevalence of respiratory symptoms and their association with sociodemographic variables and with the characteristics of the work environment. A cross-sectional study comprising 464 workers employed at ceramics manufacturing facilities located in the city of Várzea Grande, Brazil. Data were collected by means of a questionnaire comprising questions regarding sociodemographic variables, work environment characteristics, and respiratory symptoms. Data were analyzed by means of prevalence ratios and their respective 95% CIs between the dependent variable (respiratory symptoms) and the other explanatory variables. In the multivariate analysis, two hierarchical models were built, the response variables being "all respiratory symptoms" and "severe respiratory symptoms". In the sample studied, the prevalence of "all respiratory symptoms" was 78%, whereas that of "severe respiratory symptoms" was 35%. The factors associated with "all respiratory symptoms" were gender, age bracket, level of education, type of occupation, exposure to dust, and exposure to chemical products. The factors associated with "severe respiratory symptoms" were level of education, exposure to dust, and exposure to chemical products. Our results indicate the presence of upper and lower airway disease in the population studied.

Estimation of Particulate Mass and Manganese Exposure Levels among Welders

PubMed Central

Hobson, Angela; Seixas, Noah; Sterling, David; Racette, Brad A.

2011-01-01

Background: Welders are frequently exposed to Manganese (Mn), which may increase the risk of neurological impairment. Historical exposure estimates for welding-exposed workers are needed for epidemiological studies evaluating the relationship between welding and neurological or other health outcomes. The objective of this study was to develop and validate a multivariate model to estimate quantitative levels of welding fume exposures based on welding particulate mass and Mn concentrations reported in the published literature. Methods: Articles that described welding particulate and Mn exposures during field welding activities were identified through a comprehensive literature search. Summary measures of exposure and related determinants such as year of sampling, welding process performed, type of ventilation used, degree of enclosure, base metal, and location of sampling filter were extracted from each article. The natural log of the reported arithmetic mean exposure level was used as the dependent variable in model building, while the independent variables included the exposure determinants. Cross-validation was performed to aid in model selection and to evaluate the generalizability of the models. Results: A total of 33 particulate and 27 Mn means were included in the regression analysis. The final model explained 76% of the variability in the mean exposures and included welding process and degree of enclosure as predictors. There was very little change in the explained variability and root mean squared error between the final model and its cross-validation model indicating the final model is robust given the available data. Conclusions: This model may be improved with more detailed exposure determinants; however, the relatively large amount of variance explained by the final model along with the positive generalizability results of the cross-validation increases the confidence that the estimates derived from this model can be used for estimating welder exposures in absence of individual measurement data. PMID:20870928

Cardiovascular health effects following exposure of human volunteers during fire extinction exercises.

PubMed

Andersen, Maria Helena Guerra; Saber, Anne Thoustrup; Pedersen, Peter Bøgh; Loft, Steffen; Hansen, Åse Marie; Koponen, Ismo Kalevi; Pedersen, Julie Elbæk; Ebbehøj, Niels; Nørskov, Eva-Carina; Clausen, Per Axel; Garde, Anne Helene; Vogel, Ulla; Møller, Peter

2017-09-06

Firefighters have increased risk of cardiovascular disease and of sudden death from coronary heart disease on duty while suppressing fires. This study investigated the effect of firefighting activities, using appropriate personal protective equipment (PPE), on biomarkers of cardiovascular effects in young conscripts training to become firefighters. Healthy conscripts (n = 43) who participated in a rescue educational course for firefighting were enrolled in the study. The exposure period consisted of a three-day training course where the conscripts participated in various firefighting exercises in a constructed firehouse and flashover container. The subjects were instructed to extinguish fires of either wood or wood with electrical cords and mattresses. The exposure to particulate matter (PM) was assessed at various locations and personal exposure was assessed by portable PM samplers and urinary excretion of 1-hydroxypyrene. Cardiovascular measurements included microvascular function and heart rate variability (HRV). The subjects were primarily exposed to PM in bystander positions, whereas self-contained breathing apparatus effectively abolished pulmonary exposure. Firefighting training was associated with elevated urinary excretion of 1-hydroxypyrene (105%, 95% CI: 52; 157%), increased body temperature, decreased microvascular function (-18%, 95% CI: -26; -9%) and altered HRV. There was no difference in cardiovascular measurements for the two types of fires. Observations from this fire extinction training show that PM exposure mainly occurs in situations where firefighters removed the self-contained breathing apparatus. Altered cardiovascular disease endpoints after the firefighting exercise period were most likely due to complex effects from PM exposure, physical exhaustion and increased core body temperature.

Comparing the effects of entertainment media and tobacco marketing on youth smoking in Germany

PubMed Central

Sargent, James D.; Hanewinkel, Reiner

2013-01-01

Aims To examine differential effects of smoking in films and tobacco advertising on adolescent smoking. We hypothesize that movie smoking will have greater effects on smoking initiation, whereas tobacco advertising receptivity will primarily affect experimentation. Design Longitudinal observational study of adolescents. Setting School-based surveys conducted in Schleswig-Holstein, Germany. Participants A total of 4384 adolescents age 11–15 years at baseline and re-surveyed 1 year later; ever smoking prevalence was 38% at time 1. Measurements The main outcome variable combined two items assessing life-time and current smoking (alpha = 0.87). Baseline never smokers were analyzed separately from those who had tried smoking (ever smokers). Exposure to smoking in 398 internationally distributed US movies was modeled as a continuous variable, with 0 corresponding to the 5th percentile and 1 to the 95th percentile of exposure. Tobacco marketing receptivity consisted of naming a brand for a favorite tobacco advertisement. Ordinal logistic regressions controlled for socio-demographics, other social influences, personality characteristics of the adolescent and parenting style. Findings Whereas 34% of ever smokers were receptive to tobacco marketing at time 1, only 6% of never smokers were. Among time 1 never smokers, exposure to movie smoking was a significantly stronger predictor of higher time 2 smoking level [adjusted proportional odds ratio = 2.76, 95% confidence interval (1.84, 4.15)] than was tobacco marketing receptivity (1.53 [1.07, 2.20]). Among time 1 ever smokers, both tobacco marketing receptivity and exposure to movie smoking predicted higher levels of time 2 smoking [2.17 (1.78, 2.63) and 1.62 (1.18, 2.23), respectively], and the two estimates were not significantly different. Conclusions In this longitudinal study, exposure to movie smoking was a stronger predictor of smoking initiation than tobacco marketing receptivity, which was more common among ever smokers. The results suggest that entertainment media smoking should be emphasized in programs aimed at preventing onset, and both exposures should be emphasized in programs aimed at experimental smokers. PMID:19413793

The influence of redox status on inter-individual variability in the response of human peripheral blood lymphocytes to ionizing radiation.

PubMed

Pajic, Jelena; Rovcanin, Branislav; Kekic, Dusan; Jovicic, Dubravka; Milovanovic, Aleksandar P S

2018-04-30

Ionizing radiation (IR) can act on atomic structures, producing damage to biomolecules. Earlier investigations evaluating individual radiosensitivity in vitro were focused on cytogenetic biomarkers (chromosomal aberrations - CA and micronuclei - MN). Since IR can also cause oxidative damage by producing reactive oxygen species, the main goal of this investigation was to establish the influence of redox status on CA and MN frequency in human peripheral blood lymphocytes. Blood samples from 56 healthy donors were irradiated at doses of 0, 0.75, 1.5 and 3 Gy and then analyzed cytogenetically and biochemically. The results showed inter-individual variability in all analyzed parameters, as well as dose-dependent increases in almost all of them. Correlation analysis indicated no association between CA, MN and oxidative stress parameters. However, findings for overall response (HRR) parameters showed that donors with lower values for parameters of antioxidant status had increased levels of cytogenetic damage and higher responses to irradiation and vice versa. Besides well-established cytogenetic biomarkers of radiation exposure, our results indicated promising future use for biochemical oxidative status parameters in routine radiation protection practice, since together they can provide a complete radiation response profile in cases of continuous low-dose exposure, as well as in a radiation emergency.

Evaluation of daily time spent in transportation and traffic-influenced microenvironments by urban Canadians.

PubMed

Matz, Carlyn J; Stieb, David M; Egyed, Marika; Brion, Orly; Johnson, Markey

2018-01-01

Exposure to traffic and traffic-related air pollution is associated with a wide array of health effects. Time spent in a vehicle, in active transportation, along roadsides, and in close proximity to traffic can substantially contribute to daily exposure to air pollutants. For this study, we evaluated daily time spent in transportation and traffic-influenced microenvironments by urban Canadians using the Canadian Human Activity Pattern Survey (CHAPS) 2 results. Approximately 4-7% of daily time was spent in on- or near-road locations, mainly associated with being in a vehicle and smaller contributions from active transportation. Indoor microenvironments can be impacted by traffic emissions, especially when located near major roadways. Over 60% of the target population reported living within one block of a roadway with moderate to heavy traffic, which was variable with income level and city, and confirmed based on elevated NO 2 exposure estimated using land use regression. Furthermore, over 55% of the target population ≤ 18 years reported attending a school or daycare in close proximity to moderate to heavy traffic, and little variation was observed based on income or city. The results underline the importance of traffic emissions as a major source of exposure in Canadian urban centers, given the time spent in traffic-influenced microenvironments.

Vitamin D Beliefs and Associations with Sunburns, Sun Exposure, and Sun Protection

PubMed Central

Kim, Bang Hyun; Glanz, Karen; Nehl, Eric J.

2012-01-01

The main objective of this study was to examine certain beliefs about vitamin D and associations with sun exposure, sun protection behaviors, and sunburns. A total of 3,922 lifeguards, pool managers, and parents completed a survey in 2006 about beliefs regarding vitamin D and sun-related behaviors. Multivariate ordinal regression analyses and linear regression analysis were used to examine associations of beliefs and other variables. Results revealed that Non-Caucasian lifeguards and pool managers were less likely to agree that they needed to go out in the sun to get enough vitamin D. Lifeguards and parents who were non-Caucasian were less likely to report that sunlight helped the body to produce vitamin D. A stronger belief about the need to go out in the sun to get enough vitamin D predicted more sun exposure for lifeguards. For parents, a stronger belief that they can get enough vitamin D from foods predicted greater sun protection and a stronger belief that sunlight helps the body produce vitamin D predicted lower sun exposure. This study provides information regarding vitamin D beliefs and their association with certain sun related behaviors across different demographic groups that can inform education efforts about vitamin D and sun protection. PMID:22851950

Identifying attentional bias and emotional response after appearance-related stimuli exposure.

PubMed

Cho, Ara; Kwak, Soo-Min; Lee, Jang-Han

2013-01-01

The effect of media images has been regarded as a significant variable in the construction or in the activation of body images. Individuals who have a negative body image use avoidance coping strategies to minimize damage to their body image. We identified attentional biases and negative emotional responses following exposure to body stimuli. Female university students were divided into two groups based on their use of avoidance coping strategies (high-level group: high avoidance [HA]; low-group: low avoidance [LA]), and were assigned to two different conditions (exposure to thin body pictures, ET, and exposure to oversized body pictures, EO). Results showed that the HA group paid more attention to slim bodies and reported more negative emotions than the LA group, and that the EO had more negative effects than the ET. We suggest that HAs may attend more to slim bodies as a way of avoiding overweight bodies, influenced by social pressure, and in the search for a compensation of a positive emotional balance. However, attentional bias toward slim bodies can cause an upward comparison process, leading to increased body dissatisfaction, which is the main factor in the development of eating disorders (EDs). Therefore, altering avoidance coping strategies should be considered for people at risk of EDs.

Studies in the epidemiology of prostatic cancer: expanded sampling.

PubMed

Rotkin, I D

1977-01-01

From comparisons of prostatic cancer patients with matched control patients for selected risk variables, patients are characterized by three main trends: (a) delayed sexual drive and development, (b) early repression of sexuality, and (c) premature cessation of sexuality. Excessive numbers of patients reported occupational exposure to fertilizers and auto exhaust fumes. Diets of the patients were higher in animal fats. No differences were found between both groups for frequencies of multiple marriages or sex partners, nor for stressful effects from selected events early or late in life. Trends for circumcision and other variables are presented. The data suggest that early differences are hormonally conditioned, support a provisional endogenous rationale for initiation of prostatic cancer, and oppose a hypothesis favoring transmissible oncogenic agents. If results continue to hold up with increased sampling, limitation upon sexual activity at any time of life may increase risk.

Electrochemistry and capillary condensation theory reveal the mechanism of corrosion in dense porous media.

PubMed

Stefanoni, Matteo; Angst, Ueli M; Elsener, Bernhard

2018-05-09

Corrosion in carbonated concrete is an example of corrosion in dense porous media of tremendous socio-economic and scientific relevance. The widespread research endeavors to develop novel, environmentally friendly cements raise questions regarding their ability to protect the embedded steel from corrosion. Here, we propose a fundamentally new approach to explain the scientific mechanism of corrosion kinetics in dense porous media. The main strength of our model lies in its simplicity and in combining the capillary condensation theory with electrochemistry. This reveals that capillary condensation in the pore structure defines the electrochemically active steel surface, whose variability upon changes in exposure relative humidity is accountable for the wide variability in measured corrosion rates. We performed experiments that quantify this effect and find good agreement with the theory. Our findings are essential to devise predictive models for the corrosion performance, needed to guarantee the safety and sustainability of traditional and future cements.

The influence of demographic characteristics, living conditions, and trauma exposure on the overall health of a conflict-affected population in Southern Sudan.

PubMed

Roberts, Bayard; Damundu, Eliaba Yona; Lomoro, Olivia; Sondorp, Egbert

2010-08-27

There remains limited evidence on how armed conflict affects overall physical and mental well-being rather than specific physical or mental health conditions. The aim of this study was to investigate the influence of demographic characteristics, living conditions, and violent and traumatic events on general physical and mental health in Southern Sudan which is emerging from 20 years of armed conflict. A cross-sectional survey of 1228 adults was conducted in November 2007 in the town of Juba, the capital of Southern Sudan. Multivariate linear regression analysis was used to investigate the associations and relative influence of variables in three models of demographic characteristics, living conditions, and trauma exposure, on general physical and mental health status. These models were run separately and also as a combined model. Data quality and the internal consistency of the health status instrument (SF-8) were assessed. The variables in the multivariate analysis (combined model) with negative coefficients of association with general physical health and mental health (i.e. worse health), respectively, were being female (coef. -2.47; -2.63), higher age (coef.-0.16; -0.17), absence of soap in the household (physical health coef. -2.24), and experiencing within the past 12 months a lack of food and/or water (coef. -1.46; -2.27) and lack of medical care (coef.-3.51; -3.17). A number of trauma variables and cumulative exposure to trauma showed an association with physical and mental health (see main text for data). There was limited variance in results when each of the three models were run separately and when they were combined, suggesting the pervasive influence of these variables. The SF-8 showed good data quality and internal consistency. This study provides evidence on the pervasive influence of demographic characteristics, living conditions, and violent and traumatic events on the general physical and mental health of a conflict-affected population in Southern Sudan, and highlights the importance of addressing all these influences on overall health.

The influence of demographic characteristics, living conditions, and trauma exposure on the overall health of a conflict-affected population in Southern Sudan

PubMed Central

2010-01-01

Background There remains limited evidence on how armed conflict affects overall physical and mental well-being rather than specific physical or mental health conditions. The aim of this study was to investigate the influence of demographic characteristics, living conditions, and violent and traumatic events on general physical and mental health in Southern Sudan which is emerging from 20 years of armed conflict. Methods A cross-sectional survey of 1228 adults was conducted in November 2007 in the town of Juba, the capital of Southern Sudan. Multivariate linear regression analysis was used to investigate the associations and relative influence of variables in three models of demographic characteristics, living conditions, and trauma exposure, on general physical and mental health status. These models were run separately and also as a combined model. Data quality and the internal consistency of the health status instrument (SF-8) were assessed. Results The variables in the multivariate analysis (combined model) with negative coefficients of association with general physical health and mental health (i.e. worse health), respectively, were being female (coef. -2.47; -2.63), higher age (coef.-0.16; -0.17), absence of soap in the household (physical health coef. -2.24), and experiencing within the past 12 months a lack of food and/or water (coef. -1.46; -2.27) and lack of medical care (coef.-3.51; -3.17). A number of trauma variables and cumulative exposure to trauma showed an association with physical and mental health (see main text for data). There was limited variance in results when each of the three models were run separately and when they were combined, suggesting the pervasive influence of these variables. The SF-8 showed good data quality and internal consistency. Conclusions This study provides evidence on the pervasive influence of demographic characteristics, living conditions, and violent and traumatic events on the general physical and mental health of a conflict-affected population in Southern Sudan, and highlights the importance of addressing all these influences on overall health. PMID:20799956

Solid-phase microextraction set-up for the analysis of liver volatolome to detect livestock exposure to micropollutants.

PubMed

Bouhlel, Jihéne; Ratel, Jérémy; Abouelkaram, Said; Mercier, Frédéric; Travel, Angelique; Baéza, Elisabeth; Jondreville, Catherine; Dervilly-Pinel, Gaud; Marchand, Philippe; Le Bizec, Bruno; Dubreil, Estelle; Mompelat, Sophie; Verdon, Eric; Inthavong, Chanthadary; Guérin, Thierry; Rutledge, Douglas N; Engel, Erwan

2017-05-12

Starting from a critical analysis of a first "proof of concept" study on the utility of the liver volatolome for detecting livestock exposure to environmental micropollutants (Berge et al., 2011), the primary aim of this paper is to improve extraction conditions so as to obtain more representative extracts by using an extraction temperature closer to livestock physiological conditions while minimizing analytical variability and maximizing Volatile Organic Compound (VOC) abundancies. Levers related to extraction conditions and sample preparation were assessed in the light of both abundance and coefficient of variation of 22 candidate VOC markers identified in earlier volatolomic studies. Starting with a CAR/PDMS fiber and a 30min extraction, the reduction of SPME temperature to 40°C resulted in a significant decrease in the area of 14 candidate VOC markers (p<0.05), mainly carbonyls and alcohols but also a reduction in the coefficient of variation for 17 of them. In order to restore VOC abundances and to minimize variability, two approaches dealing with sample preparation were investigated. By increasing sample defrosting time at 4°C from 0 to 24h yielded higher abundances and lower variabilities for 15 and 13 compounds, respectively. Lastly, by using additives favouring the release of VOCs (1.2g of NaCl) the sensitivity of the analysis was improved with a significant increase in VOC abundances of more than 50% for 13 out of the 22 candidate markers. The modified SPME parameters significantly enhanced the abundances while decreasing the analytical variability for most candidate VOC markers. The second step was to validate the ability of the revised SPME protocol to discriminate intentionally contaminated broiler chickens from controls, under case/control animal testing conditions. After verification of the contamination levels of the animals by national reference laboratories, data analysis by a multivariate chemometric method (Common Components and Specific Weights Analysis - ComDim) showed that the liver volatolome could reveal dietary exposure of broilers to a group of environmental pollutants (PCBs), a veterinary treatment (monensin), and a pesticide (deltamethrin), thus confirming the usefulness of this analytical set-up. Copyright © 2017 Elsevier B.V. All rights reserved.

A Simulation Study of Categorizing Continuous Exposure Variables Measured with Error in Autism Research: Small Changes with Large Effects.

PubMed

Heavner, Karyn; Burstyn, Igor

2015-08-24

Variation in the odds ratio (OR) resulting from selection of cutoffs for categorizing continuous variables is rarely discussed. We present results for the effect of varying cutoffs used to categorize a mismeasured exposure in a simulated population in the context of autism spectrum disorders research. Simulated cohorts were created with three distinct exposure-outcome curves and three measurement error variances for the exposure. ORs were calculated using logistic regression for 61 cutoffs (mean ± 3 standard deviations) used to dichotomize the observed exposure. ORs were calculated for five categories with a wide range for the cutoffs. For each scenario and cutoff, the OR, sensitivity, and specificity were calculated. The three exposure-outcome relationships had distinctly shaped OR (versus cutoff) curves, but increasing measurement error obscured the shape. At extreme cutoffs, there was non-monotonic oscillation in the ORs that cannot be attributed to "small numbers." Exposure misclassification following categorization of the mismeasured exposure was differential, as predicted by theory. Sensitivity was higher among cases and specificity among controls. Cutoffs chosen for categorizing continuous variables can have profound effects on study results. When measurement error is not too great, the shape of the OR curve may provide insight into the true shape of the exposure-disease relationship.

Variability in PAH-DNA adduct measurements in peripheral mononuclear cells: implications for quantitative cancer risk assessment.

PubMed

Dickey, C; Santella, R M; Hattis, D; Tang, D; Hsu, Y; Cooper, T; Young, T L; Perera, F P

1997-10-01

Biomarkers such as DNA adducts have significant potential to improve quantitative risk assessment by characterizing individual differences in metabolism of genotoxins and DNA repair and accounting for some of the factors that could affect interindividual variation in cancer risk. Inherent uncertainty in laboratory measurements and within-person variability of DNA adduct levels over time are putatively unrelated to cancer risk and should be subtracted from observed variation to better estimate interindividual variability of response to carcinogen exposure. A total of 41 volunteers, both smokers and nonsmokers, were asked to provide a peripheral blood sample every 3 weeks for several months in order to specifically assess intraindividual variability of polycyclic aromatic hydrocarbon (PAH)-DNA adduct levels. The intraindividual variance in PAH-DNA adduct levels, together with measurement uncertainty (laboratory variability and unaccounted for differences in exposure), constituted roughly 30% of the overall variance. An estimated 70% of the total variance was contributed by interindividual variability and is probably representative of the true biologic variability of response to carcinogenic exposure in lymphocytes. The estimated interindividual variability in DNA damage after subtracting intraindividual variability and measurement uncertainty was 24-fold. Inter-individual variance was higher (52-fold) in persons who constitutively lack the Glutathione S-Transferase M1 (GSTM1) gene which is important in the detoxification pathway of PAH. Risk assessment models that do not consider the variability of susceptibility to DNA damage following carcinogen exposure may underestimate risks to the general population, especially for those people who are most vulnerable.

Adult tooth loss for residents of US coal mining and Appalachian counties.

PubMed

Hendryx, Michael; Ducatman, Alan M; Zullig, Keith J; Ahern, Melissa M; Crout, Richard

2012-12-01

The authors compared rates of tooth loss between adult residents of Appalachian coal-mining areas and other areas of the nation before and after control for covariate risks. The authors conducted a cross-sectional secondary data analysis that merged 2006 national Behavioral Risk Factor Surveillance System data (BRFSS) (N = 242 184) with county coal-mining data and other county characteristics. The hypothesis tested was that adult tooth loss would be greater in Appalachian mining areas after control for other risks. Primary independent variables included main effects for coal-mining present (yes/no) residence in Appalachia (yes/no), and their interaction. Data were weighted using the BRFSS final weights and analyzed using SUDAAN Proc Multilog to account for the multilevel complex sampling structure. The odds of two measures of tooth loss were examined controlling for age, race\\ethnicity, drinking, smoking, income, education, supply of dentists, receipt of dental care, fluoridation rate, and other variables. After covariate adjustment, the interaction variable for the residents of Appalachian coal-mining counties showed a significantly elevated odds for any tooth loss [odds ratio (OR) = 1.19, 95% CI = 1.02, 1.38], and greater tooth loss measured by a 4-level edentulism scale (OR = 1.20, 95% CI = 1.05, 1.36). The main effect for Appalachia was also significant for both measures, but the main effect for coal mining was not. Greater risk of tooth loss among adult residents of Appalachian coal-mining areas is present and is not explained by differences in reported receipt of dental care, fluoridation rates, supply of dentists or other behavioral or socioeconomic risks. Possible contributing factors include mining-specific disparities related to access, behavior or environmental exposures. © 2012 John Wiley & Sons A/S.

To Each Their Own: Molecular Mechanisms of Inter-Individual Variability in Toxic Exposure Effects

EPA Science Inventory

Traditional approaches to identifying susceptible populations have relied on factors such as age, genotype, and disease status to explain variability in exposure outcomes; however, these are neither sufficient to faithfully identify differentially responsive individuals nor are t...

AGE-DEPENDENT HETEROGENEITY OF GENE EXPRESSIONS IN FISHER 344 RAT RETINAL.

EPA Science Inventory

Recent evidence suggests the elderly may be a sensitive subpopulation with regard to environmental exposure to toxic compounds. One source of this sensitivity within the aged subpopulation could be an enhanced variability in response to exposures. This variability, if sufficien...

Pre-vitamin D effective ultraviolet transmission through clothing during simulated wear.

PubMed

Parisi, A V; Wilson, C A

2005-12-01

Clothing is an important protective layer used to reduce ultraviolet (UV) exposures to the skin surface. However, not all UV exposure is linked to detrimental health effects with some exposure to UVB wavelengths below 316 nm required for the synthesis of pre-vitamin D(3). The aim of the current research was to investigate the effect of fabric type, color, fit, and wetness on the transmission of pre-vitamin D(3) effective UV through garments during simulated wear, in a high UV exposure environment. Dosimeters fabricated from polysulfone film were positioned at eight selected body sites on the skin surface and clothing surface of identically designed, loose and fitted, black and white T-shirts made up in two knitted fabric types and tested when both dry and when drying after initial wetting (n=3 replicates). The T-shirts were placed on manikins set to simulate humans in the sun between 09:30 and 12:30 Eastern Standard Time during the Southern Hemisphere summer period. The post-exposure absorbance was measured and the dosimeters were calibrated for biologically effective UV for pre-vitamin D(3) synthesis with a UV spectroradiometer. The effect of fit, fabric type, color, and wetness on pre-vitamin D(3) effective UV transmission during simulated wear was assessed. Irradiances varied among body sites with the highest erythemal exposures to a horizontal plane over the 3 h period reaching approximately 14.5 minimal erythema dose (MED) while the highest exposure under the garment was 0.22 MED which may not be above the threshold for pre-vitamin D(3) synthesis for the time period investigated. Fabric and fit were the main variables affecting transmission of pre-vitamin D(3) effective UV. Some interactions were identified between the fabric color and wetness and between fabric type and color; however, while significantly modifying transmission these effects were small. Transmission of pre-vitamin D(3) effective UV occurred through the high UPF knitted fabrics investigated. However, the length of exposure will influence whether the irradiances are sufficient to be above the threshold for pre-vitamin D(3) synthesis. The main effect on transmission of pre-vitamin D(3) effective UV was the fit of the T-shirt and its fabric type (probably structure) rather than color or degree of wetness.

Assessing human variability in kinetics for exposures to multiple environmental chemicals: a physiologically based pharmacokinetic modeling case study with dichloromethane, benzene, toluene, ethylbenzene, and m-xylene.

PubMed

Valcke, Mathieu; Haddad, Sami

2015-01-01

The objective of this study was to compare the magnitude of interindividual variability in internal dose for inhalation exposure to single versus multiple chemicals. Physiologically based pharmacokinetic models for adults (AD), neonates (NEO), toddlers (TODD), and pregnant women (PW) were used to simulate inhalation exposure to "low" (RfC-like) or "high" (AEGL-like) air concentrations of benzene (Bz) or dichloromethane (DCM), along with various levels of toluene alone or toluene with ethylbenzene and xylene. Monte Carlo simulations were performed and distributions of relevant internal dose metrics of either Bz or DCM were computed. Area under the blood concentration of parent compound versus time curve (AUC)-based variability in AD, TODD, and PW rose for Bz when concomitant "low" exposure to mixtures of increasing complexities occurred (coefficient of variation (CV) = 16-24%, vs. 12-15% for Bz alone), but remained unchanged considering DCM. Conversely, AUC-based CV in NEO fell (15 to 5% for Bz; 12 to 6% for DCM). Comparable trends were observed considering production of metabolites (AMET), except for NEO's CYP2E1-mediated metabolites of Bz, where an increased CV was observed (20 to 71%). For "high" exposure scenarios, Cmax-based variability of Bz and DCM remained unchanged in AD and PW, but decreased in NEO (CV= 11-16% to 2-6%) and TODD (CV= 12-13% to 7-9%). Conversely, AMET-based variability for both substrates rose in every subpopulation. This study analyzed for the first time the impact of multiple exposures on interindividual variability in toxicokinetics. Evidence indicates that this impact depends upon chemical concentrations and biochemical properties, as well as the subpopulation and internal dose metrics considered.

Instrumental variables estimation of exposure effects on a time-to-event endpoint using structural cumulative survival models.

PubMed

Martinussen, Torben; Vansteelandt, Stijn; Tchetgen Tchetgen, Eric J; Zucker, David M

2017-12-01

The use of instrumental variables for estimating the effect of an exposure on an outcome is popular in econometrics, and increasingly so in epidemiology. This increasing popularity may be attributed to the natural occurrence of instrumental variables in observational studies that incorporate elements of randomization, either by design or by nature (e.g., random inheritance of genes). Instrumental variables estimation of exposure effects is well established for continuous outcomes and to some extent for binary outcomes. It is, however, largely lacking for time-to-event outcomes because of complications due to censoring and survivorship bias. In this article, we make a novel proposal under a class of structural cumulative survival models which parameterize time-varying effects of a point exposure directly on the scale of the survival function; these models are essentially equivalent with a semi-parametric variant of the instrumental variables additive hazards model. We propose a class of recursive instrumental variable estimators for these exposure effects, and derive their large sample properties along with inferential tools. We examine the performance of the proposed method in simulation studies and illustrate it in a Mendelian randomization study to evaluate the effect of diabetes on mortality using data from the Health and Retirement Study. We further use the proposed method to investigate potential benefit from breast cancer screening on subsequent breast cancer mortality based on the HIP-study. © 2017, The International Biometric Society.

Does habituation matter? Emotional processing theory and exposure therapy for acrophobia.

PubMed

Baker, Aaron; Mystkowski, Jayson; Culver, Najwa; Yi, Rena; Mortazavi, Arezou; Craske, Michelle G

2010-11-01

Clinically, there is wide subscription to emotional processing theory (EPT; Foa & Kozak, 1986) as a model of therapeutic effectiveness of exposure therapy: EPT purports that exposure is maximal when (1) fear is activated (IFA), (2) fear subsides within sessions (WSH), and (3) fear subsides between sessions (BSH). This study examined these assumptions, using in vivo exposure therapy for 44 students scoring high on acrophobia measures. Results indicated that no EPT variables were consistently predictive of treatment outcome. No support was found for IFA or WSH; measures of BSH were predictive of short-term change, but these effects were attenuated at follow-up. Furthermore, EPT variables were not predictive of each other as previously hypothesized, indicating the variables are not functionally related. Copyright © 2010 Elsevier Ltd. All rights reserved.

Comparison of individual-based modeling and population approaches for prediction of foodborne pathogens growth.

PubMed

Augustin, Jean-Christophe; Ferrier, Rachel; Hezard, Bernard; Lintz, Adrienne; Stahl, Valérie

2015-02-01

Individual-based modeling (IBM) approach combined with the microenvironment modeling of vacuum-packed cold-smoked salmon was more effective to describe the variability of the growth of a few Listeria monocytogenes cells contaminating irradiated salmon slices than the traditional population models. The IBM approach was particularly relevant to predict the absence of growth in 25% (5 among 20) of artificially contaminated cold-smoked salmon samples stored at 8 °C. These results confirmed similar observations obtained with smear soft cheese (Ferrier et al., 2013). These two different food models were used to compare the IBM/microscale and population/macroscale modeling approaches in more global exposure and risk assessment frameworks taking into account the variability and/or the uncertainty of the factors influencing the growth of L. monocytogenes. We observed that the traditional population models significantly overestimate exposure and risk estimates in comparison to IBM approach when contamination of foods occurs with a low number of cells (<100 per serving). Moreover, the exposure estimates obtained with the population model were characterized by a great uncertainty. The overestimation was mainly linked to the ability of IBM to predict no growth situations rather than the consideration of microscale environment. On the other hand, when the aim of quantitative risk assessment studies is only to assess the relative impact of changes in control measures affecting the growth of foodborne bacteria, the two modeling approach gave similar results and the simplest population approach was suitable. Copyright © 2014 Elsevier Ltd. All rights reserved.

Job enlargement and mechanical exposure variability in cyclic assembly work.

PubMed

Möller, Therése; Mathiassen, Svend Erik; Franzon, Helena; Kihlberg, Steve

2004-01-15

Cyclic assembly work is known to imply a high risk for musculoskeletal disorders. To have operators rotate between work tasks is believed to be one way of decreasing this risk, since it is expected to increase variation in mechanical and psychological exposures (physical and mental loads). This assumption was investigated by assessing mechanical exposure variability in three assembly tasks in an electronics assembly plant, each on a separate workstation, as well as in a 'job enlargement' scenario combining all three stations. Five experienced operators worked for 1 h on each station. Data on upper trapezius and forearm extensor muscle activity were obtained by means of electromyography (EMG), and working postures of the head and upper arms were assessed by inclinometry. The cycle-to-cycle variance of parameters representing the three exposure dimensions: level, frequency and duration was estimated using ANOVA algorithms for each workstation separately as well as for a balanced combination of all three. For a particular station, the variability of trapezius EMG activity levels relative to the mean was higher than for extensor EMG: between-cycles coefficients of variation (CV) about 0.15 and 0.10, respectively. A similar relationship between CV applied to the parameter describing frequency of EMG activity. Except for head inclination levels, the between-cycles CV was larger for posture parameters than for EMG. The between-cycles variance increased up to six fold in the job enlargement scenario, as compared to working at only one station. The difference in mean exposure between workstations was larger for trapezius EMG parameters than for forearm extensor EMG and postures, and hence the effect of job enlargement on exposure variability was more pronounced for the trapezius. For some stations, job enlargement even implied less cycle-to-cycle variability in forearm extensor EMG parameters than working at that station only. Whether the changes in exposure variability associated with job enlargement were sufficient to imply a decreased risk for musculoskeletal disorders is not known.

Eliminating Survivor Bias in Two-stage Instrumental Variable Estimators.

PubMed

Vansteelandt, Stijn; Walter, Stefan; Tchetgen Tchetgen, Eric

2018-07-01

Mendelian randomization studies commonly focus on elderly populations. This makes the instrumental variables analysis of such studies sensitive to survivor bias, a type of selection bias. A particular concern is that the instrumental variable conditions, even when valid for the source population, may be violated for the selective population of individuals who survive the onset of the study. This is potentially very damaging because Mendelian randomization studies are known to be sensitive to bias due to even minor violations of the instrumental variable conditions. Interestingly, the instrumental variable conditions continue to hold within certain risk sets of individuals who are still alive at a given age when the instrument and unmeasured confounders exert additive effects on the exposure, and moreover, the exposure and unmeasured confounders exert additive effects on the hazard of death. In this article, we will exploit this property to derive a two-stage instrumental variable estimator for the effect of exposure on mortality, which is insulated against the above described selection bias under these additivity assumptions.

Interactive effects of photoperiod and light intensity on blood physiological and biochemical reactions of broilers grown to heavy weights.

PubMed

Olanrewaju, H A; Purswell, J L; Collier, S D; Branton, S L

2013-04-01

The effects of photoperiod, light intensity, and their interaction on blood acid-base balance, metabolites, and electrolytes in broiler chickens under environmentally controlled conditions were examined in 2 trials. A 3 × 3 factorial experiment in a randomized complete block design was used in this study. In each trial, all treatment groups were provided 23L:1D with 20 lx of intensity from placement to 7 d, and then subjected to the treatments. The 9 treatments consisted of 3 photoperiods [long/continuous (23L:1D) from d 8 to 56, regular/intermittent (2L:2D), and short/nonintermittent (8L:16D) from d 8 to 48 and 23L:1D from d 49 to 56, respectively] and exposure to 3 light intensities (10, 5.0, and 0.5 lx) from d 8 through d 56 at 50% RH. Feed and water were provided ad libitum. Venous blood samples were collected on d 7, 14, 28, 42, and 56. Main effects indicated that short/nonintermittent photoperiod significantly (P < 0.05) reduced BW, pH, partial pressure of O2, saturated O2, Na(+), K(+), Ca(2+), Cl(-), osmolality, triiodothyronine (T3), and total protein along with significantly (P < 0.05) elevated partial pressure of CO2, hematocrit, hemoglobin, and lactate concentrations. In addition, there were no effects of photoperiod on HCO3(-), glucose, anion gap, and thyroxine (T4). Plasma corticosterone was not affected by photoperiod, light intensity, or their interaction. There was no effect of light intensity on most of the blood variables examined. Acid-base regulation during photoperiod and light intensity exposure did not deteriorate despite a lower pH and higher partial pressure of CO2 with normal HCO3(-). These results indicate that continuous exposure of broiler chickens to varying light intensities had a minor effect on blood physiological variables, whereas the short photoperiod markedly affected most blood physiological variables without inducing physiological stress in broilers.

Caries Experience among Adults Exposed to Low to Moderate Doses of Ionizing Radiation in Childhood - The Tinea Capitis Cohort.

PubMed

Vered, Yuval; Chetrit, Angela; Sgan-Cohen, Harold D; Amitai, Tova; Mann, Jonathan; Even-Nir, Hadas; Sadetzki, Siegal

2016-01-01

While the impact of therapeutic levels of ionizing radiation during childhood on dental defects has been documented, the possible effect of low doses on dental health is unknown. The study aim was to assess the association between childhood exposure to low-moderate doses of therapeutic radiation and caries experience among a cohort of adults 50 years following the exposure. The analysis was based on a sample of 253 irradiated (in the treatment of tinea capitis) and 162 non-irradiated subjects. The decayed, missing, and filled teeth (DMFT) index was assessed during a clinical dental examination and questions regarding dental care services utilization, oral hygiene behavior, current self-perceived mouth dryness, socio-demographic parameters, and health behavior variables were obtained through a face-to-face interview. An ordered multivariate logistic regression model was used to assess the association of the main independent variable (irradiation status) and other relevant independent variables on the increase in DMFT. Mean caries experience levels (DMFT) were 18.6 ± 7.5 for irradiated subjects compared to 16.4 ± 7.2 for the non-irradiated (p = 0.002). Controlling for gender, age, education, income, smoking, dental visit in the last year, and brushing teeth behavior, irradiation was associated with a 72% increased risk for higher DMFT level (95% CI: 1.19-2.50). A quantification of the risk by dose absorbed in the salivary gland and in the thyroid gland showed adjusted ORs of 2.21 per 1 Gy (95% CI: 1.40-3.50) and 1.05 per 1 cGy (95% CI: 1.01-1.09), respectively. Childhood exposure to ionizing radiation (0.2-0.4 Gy) might be associated with late outcomes of dental health. In line with the guidelines of the American Dental Association, these results call for caution when using dental radiographs.

Caries Experience among Adults Exposed to Low to Moderate Doses of Ionizing Radiation in Childhood – The Tinea Capitis Cohort

PubMed Central

Vered, Yuval; Chetrit, Angela; Sgan-Cohen, Harold D.; Amitai, Tova; Mann, Jonathan; Even-Nir, Hadas; Sadetzki, Siegal

2016-01-01

While the impact of therapeutic levels of ionizing radiation during childhood on dental defects has been documented, the possible effect of low doses on dental health is unknown. The study aim was to assess the association between childhood exposure to low–moderate doses of therapeutic radiation and caries experience among a cohort of adults 50 years following the exposure. The analysis was based on a sample of 253 irradiated (in the treatment of tinea capitis) and 162 non-irradiated subjects. The decayed, missing, and filled teeth (DMFT) index was assessed during a clinical dental examination and questions regarding dental care services utilization, oral hygiene behavior, current self-perceived mouth dryness, socio-demographic parameters, and health behavior variables were obtained through a face-to-face interview. An ordered multivariate logistic regression model was used to assess the association of the main independent variable (irradiation status) and other relevant independent variables on the increase in DMFT. Mean caries experience levels (DMFT) were 18.6 ± 7.5 for irradiated subjects compared to 16.4 ± 7.2 for the non-irradiated (p = 0.002). Controlling for gender, age, education, income, smoking, dental visit in the last year, and brushing teeth behavior, irradiation was associated with a 72% increased risk for higher DMFT level (95% CI: 1.19–2.50). A quantification of the risk by dose absorbed in the salivary gland and in the thyroid gland showed adjusted ORs of 2.21 per 1 Gy (95% CI: 1.40–3.50) and 1.05 per 1 cGy (95% CI: 1.01–1.09), respectively. Childhood exposure to ionizing radiation (0.2–0.4 Gy) might be associated with late outcomes of dental health. In line with the guidelines of the American Dental Association, these results call for caution when using dental radiographs. PMID:26942172

Effects of transcranial direct current stimulation on craving, heart-rate variability and prefrontal hemodynamics during smoking cue exposure.

PubMed

Kroczek, A M; Häußinger, F B; Rohe, T; Schneider, S; Plewnia, C; Batra, A; Fallgatter, A J; Ehlis, A-C

2016-11-01

Drug-related cue exposure elicits craving and risk for relapse during recovery. Transcranial direct current stimulation is a promising research tool and possible treatment for relapse prevention. Enhanced functional neuroconnectivity is discussed as a treatment target. The goal of this research was to examine whether transcranial direct current stimulation affected cortical hemodynamic indicators of functional connectivity, craving, and heart rate variability during smoking-related cue exposure in non-treatment-seeking smokers. In vivo smoking cue exposure supported by a 2mA transcranial direct current stimulation (anode: dorsolateral prefrontal cortex, cathode: orbitofrontal cortex; placebo-controlled, randomized, double-blind) in 29 (age: M=25, SD=5) German university students (smoking at least once a week). Cue reactivity was assessed on an autonomous (heart rate variability) and a subjective level (craving ratings). Functional near-infrared spectroscopy measured changes in the concentration of deoxygenated hemoglobin, and seed-based correlation analysis was used to quantify prefrontal connectivity of brain regions involved in cue reactivity. Cue exposure elicited increased subjective craving and heart rate variability changes in smokers. Connectivity between the orbitofrontal and dorsolateral prefrontal cortex was increased in subjects receiving verum compared to placebo stimulation (d=0.66). Hemodynamics in the left dorsolateral prefrontal cortex, however, increased in the group receiving sham stimulation (η 2 =0.140). Transcranial direct current stimulation did not significantly alter craving or heart rate variability during cue exposure. Prefrontal connectivity - between regions involved in the processing of reinforcement value and cognitive control - was increased by anodal transcranial direct current stimulation during smoking cue exposure. Possible clinical implications should be considered in future studies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

[Consequences of short term fluctuations of the environmental temperatures in calves--Part 2: Effects on the health status of animals within three weeks after exposure].

PubMed

Reinhold, P; Elmer, S

2002-04-01

The aim of the present study was to examine consequences of sudden changes in ambient temperature over a 4-hour period (see part 1 [ELMER & REINHOLD, 2002]) on respiratory health in clinically healthy calves. Therefore, the relationship between short-term changes in ambient temperature and the occurrence of clinical respiratory disease was checked over a period of 3 weeks after exposure in 10 calves exposed to 5 degrees C, in 9 calves exposed to 35 degrees C and in 8 control calves (kept at 18-20 degrees C). Within the period beginning 3 days before exposure and lasting until up to 21 days after exposure, each calf was examined clinically. Rectal temperature and respiratory rate were measured daily. All calves were euthanised on day 21 after exposure. Macroscopically visible pneumonic lesions were evaluated using a semiquantitative system. Tissue samples from tonsils, bronchi, trachea, lung and mediastinal lymph nodes were examined bacteriologically. In contrast to non-exposed control calves, severe respiratory illness was observed in individual calves of both exposed groups (5 degrees C, 35 degrees C). Significant increases in body temperature, respiratory rate and animal losses (2 calves died in the group exposed to 5 degrees C, one calf died in the group exposed to 35 degrees C) were the main clinical findings. At necropsy (3 weeks after exposure), no pneumonic lesions were observed in control calves--despite the fact that this group had the highest microbiological colonisation rates in tonsils and in large airways, i.e. trachea and bronchi, within all groups. However, variable pneumonic lung lesions were seen in remaining calves exposed to cold or warm air (5 degrees C, 35 degrees C). The microbiological examination confirmed that mainly Mycoplasma spp. were identified in the lung tissue of calves exposed to 5 degrees C while Pasteurella multocida and/or Mannheimia haemolytica were the only germs found in the lung tissue of calves exposed to 35 degrees C. The results of parts 1 and 2 of the present study related to health issues of calves should be taken into account for future legislation on animal welfare.

Mortality from non-malignant respiratory disease in the fibreglass manufacturing industry

PubMed Central

Chiazze, L; Watkins, D; Fryar, C; Fayerweather, W; Kozono, J; Biggs, V

2002-01-01

Objectives: To investigate the question of whether there is an association between workplace exposures and sociodemographic factors and mortality from non-malignant respiratory disease excluding influenza and pneumonia (NMRDxIP) among workers in a fibreglass wool manufacturing facility. Methods: A case-control study with cases and controls derived from deaths recorded from the Kansas City plant in the Owens Corning mortality surveillance system. The cases are defined as decedents with NMRDxIP as the underlying cause of death. Matched, unadjusted odds ratios (ORs) were used to assess any association between NMRDxIP and cumulative exposure history and sociodemographic factors individually. Matched, adjusted ORs were obtained by conditional logistic regression to estimate the effect of any one variable while controlling for the effect of all the others. Results: Results of the unadjusted analysis, considering variables one at a time, yielded no significant associations between NMRDxIP and any of the exposure or sociodemographic variables. The smoking OR was substantially increased (OR 5.09; 95%CI 0.65 to undeterimed). Also, there were no significant variables in a conditional logistic regression analysis in which all variables were simultaneously adjusted. ORs for respirable glass fibres were below unity at all concentrations of exposure in the adjusted analysis. For respirable silica there was no consistent relation across all exposure levels. The ORs increased through the first three exposure concentrations but decreased for the highest exposure. However, ORs although not significant, are greater than unity for all respirable concentrations of silica exposure. Conclusions: The findings for Kansas City show no association between respirable glass fibres and NMRDxIP. The adjusted ORs for all exposures to respirable fibres were less than unity. On the other hand, the ORs for silica exposures were all above unity although there was no clear dose-response relation and none of the ORs were significant. Exposures for all substances considered were very low. Further, given the number of cases and controls, the statistical power to detect relatively small increases in risk, if any increase truly exited, was relatively low. The ORs for exposures to silica were all above unity although there was no clear dose-response relation and none of the ORs were significant. These raised ORs for silica suggest that continued surveillance would be prudent. PMID:12040110

VizieR Online Data Catalog: Variable Stars in the Galactic Center (Dong+, 2017)

NASA Astrophysics Data System (ADS)

Dong, H.; Schodel, R.; William, B. F.; Nogueras-Lara, F.; Gallego-Cano, E.; Gallego-Calvente, T.; Wang, Q. D.; Morris, R. M.; Do, T.; Ghez, A.

2017-06-01

We use the 'DOLPHOT' to detect sources and extract photometry from the HST WFC3/IR observations at the F127M and F135M bands of the Galactic Centre from 2010 to 2014. The F153M observations, which are used to identify variable stars, include 290 dithered exposures from six HST programs. The detailed description of the HST dataset are given in Table 1 of the paper. We identified 33070 sources. Their F127M and F153M magnitudes, as well as their uncertainties, are given in Table 3. For each star, we used the least chi square method to identify whether it is variable or not. The output from the least chi square method are chi2y and chi2d, which are calculated from all the 290 dithered exposures and the exposures in March and April, 2014, respectively, to examine whether the star varies among years and/or days. In order to reduce the potential variation among dithered exposures, which could be potentially introduced by instrument effects, we also bin the dithered exposures and use the least chi square method to calculate chi2y,b and chi2{d,b}. We classify stars with chi2y>3 and chi2y,b>2 are variables among years and stars with chi2d>3 and chi2d,b>2 are variables among days. The detailed description about the data analysis is given in the paper. In Table 4, we gives the magnitudes of sources in individual dithered exposures, as well as the photometric uncertainties and the quality control parameters provided by 'DOLPHOT', such as signal-to-noise ratio, sharpness^2, crowd and flag. We also cross-correlated our variables with previous variable studies taken by ground-based telescopes in Table 8 and spectroscopic observations in Table 9. (4 data files).

Holocaust exposure and subsequent suicide risk: a population-based study.

PubMed

Bursztein Lipsicas, Cendrine; Levav, Itzhak; Levine, Stephen Z

2017-03-01

To examine the association between the extent of genocide exposure and subsequent suicide risk among Holocaust survivors. Persons born in Holocaust-exposed European countries during the years 1922-1945 that immigrated to Israel by 1965 were identified in the Population Registry (N = 209,429), and followed up for suicide (1950-2014). They were divided into three groups based on likely exposure to Nazi persecution: those who immigrated before (indirect; n = 20,229; 10%), during (partial direct; n = 17,189; 8%), and after (full direct; n = 172,061; 82%) World War II. Groups were contrasted for suicide risk, accounting for the extent of genocide in their respective countries of origin, high (>70%) or lower levels (<50%). Cox model survival analyses were computed examining calendar year at suicide. Sensitivity analyses were recomputed for two additional suicide-associated variables (age and years since immigration) for each exposure group. All analyses were adjusted for confounders. Survival analysis showed that compared to the indirect exposure group, the partial direct exposure group from countries with high genocide level had a statistically significant (P < .05) increased suicide risk for the main outcome (calendar year: HR 1.78, 95% CI 1.09, 2.90). This effect significantly (P < .05) replicated in two sensitivity analyses for countries with higher relative levels of genocide (age: HR 1.77, 95% CI 1.09, 2.89; years since immigration: HR 1.85, 95% CI 1.14, 3.02). The full direct exposure group was not at significant suicide risk compared to the indirect exposure group. Suicide associations for groups from countries with relative lower level of genocide were not statistically significant. This study partly converges with findings identifying Holocaust survivors (full direct exposure) as a resilient group. A tentative mechanism for higher vulnerability to suicide risk of the partial direct exposure group from countries with higher genocide exposure includes protracted guilt feelings, having directly witnessed atrocities and escaped death.

Hair analysis for the biomonitoring of pesticide exposure: comparison with blood and urine in a rat model.

PubMed

Appenzeller, Brice M R; Hardy, Emilie M; Grova, Nathalie; Chata, Caroline; Faÿs, François; Briand, Olivier; Schroeder, Henri; Duca, Radu-Corneliu

2017-08-01

Urine and plasma have been used to date for the biomonitoring of exposure to pollutants and are still the preferred fluids for this purpose; however, these fluids mainly provide information on the short term and may present a high level of variability regarding pesticide concentrations, especially for nonpersistent compounds. Hair analysis may provide information about chronic exposure that is averaged over several months; therefore, this method has been proposed as an alternative to solely relying on these fluids. Although the possibility of detecting pesticides in hair has been demonstrated over the past few years, the unknown linkage between exposure and pesticides concentration in hair has limited the recognition of this matrix as a relevant tool for assessing human exposure. Based on a rat model in which there was controlled exposure to a mixture of pesticides composed of lindane, β-hexachlorocyclohexane, β-endosulfan, p,p'-DDT, p,p'-DDE, dieldrin, pentachlorophenol, diazinon, chlorpyrifos, cyhalothrin, permethrin, cypermethrin, propiconazole, fipronil, oxadiazon, diflufenican, trifluralin, carbofuran, and propoxur, the current work demonstrates the association between exposure intensity and resulting pesticide concentration in hair. We also compared the results obtained from a hair analysis to urine and plasma collected from the same rats. Hair, blood, and urine were collected from rats submitted to 90-day exposure by gavage to the aforementioned mixture of common pesticides at different levels. We observed a linear relationship between exposure intensity and the concentration of pesticides in the rats' hair (R Pearson 0.453-0.978, p < 0.01). A comparison with results from urine and plasma samples demonstrated the relevance of hair analysis and, for many chemicals, its superiority over using fluids for differentiating animals from different groups and for re-attributing animals to their correct groups of exposure based on pesticide concentrations in the matrix. Therefore, this study strongly supports hair analysis as a reliable tool to be used during epidemiological studies to investigate exposure-associated adverse health effects.

Sensitive subgroups and normal variation in pulmonary function response to air pollution episodes.

PubMed Central

Brunekreef, B; Kinney, P L; Ware, J H; Dockery, D; Speizer, F E; Spengler, J D; Ferris, B G

1991-01-01

The Clean Air Act requires that sensitive subgroups of exposed populations be protected from adverse health effects of air pollution exposure. Hence, data suggesting the existence of sensitive subgroups can have an important impact on regulatory decisions. Some investigators have interpreted differences among individuals in observed pulmonary function response to air pollution episodes as evidence that individuals differ in their sensitivity. An alternative explanation is that the differences are due entirely to normal variation in repeated pulmonary function measurements. This paper investigates this question by reanalyzing data from three studies of children exposed to air pollution episodes to determine whether the observed variability in pulmonary function response indicates differences in sensitivity or natural interoccasion variability. One study investigated exposures to total suspended particulates (TSP), the other two investigated exposure to ozone. In all studies, each child's response to air pollution exposures was summarized by regressing that child's set of pulmonary function measurements on the air pollution concentrations on the day or days before measurement. The within-child and between-child variances of these slopes were used to test the hypothesis of variable sensitivity. Regression slopes did not vary significantly among children exposed to episodes of high TSP concentration, but there was evidence of heterogeneity in both studies of ozone exposures. The finding of heterogeneous response to ozone exposure is consistent with the epidemiologic and chamber studies of ozone exposures, but the lack of evidence for heterogeneous response to TSP exposures implies that observed variation in response can be explained by sampling variability rather than the presence of sensitive subgroup. PMID:2050060

Real versus Simulated Mobile Phone Exposures in Experimental Studies

PubMed Central

Panagopoulos, Dimitris J.; Johansson, Olle; Carlo, George L.

2015-01-01

We examined whether exposures to mobile phone radiation in biological/clinical experiments should be performed with real-life Electromagnetic Fields (EMFs) emitted by commercially available mobile phone handsets, instead of simulated EMFs emitted by generators or test phones. Real mobile phone emissions are constantly and unpredictably varying and thus are very different from simulated emissions which employ fixed parameters and no variability. This variability is an important parameter that makes real emissions more bioactive. Living organisms seem to have decreased defense against environmental stressors of high variability. While experimental studies employing simulated EMF-emissions present a strong inconsistency among their results with less than 50% of them reporting effects, studies employing real mobile phone exposures demonstrate an almost 100% consistency in showing adverse effects. This consistency is in agreement with studies showing association with brain tumors, symptoms of unwellness, and declines in animal populations. Average dosimetry in studies with real emissions can be reliable with increased number of field measurements, and variation in experimental outcomes due to exposure variability becomes less significant with increased number of experimental replications. We conclude that, in order for experimental findings to reflect reality, it is crucially important that exposures be performed by commercially available mobile phone handsets. PMID:26346766

USING CMAQ FOR EXPOSURE MODELING AND CHARACTERIZING THE SUB-GRID VARIABILITY FOR EXPOSURE ESTIMATES

EPA Science Inventory

Atmospheric processes and the associated transport and dispersion of atmospheric pollutants are known to be highly variable in time and space. Current air quality models that characterize atmospheric chemistry effects, e.g. the Community Multi-scale Air Quality (CMAQ), provide vo...

Design strategies for the International Space University's variable gravity research facility

NASA Technical Reports Server (NTRS)

Bailey, Sheila G.; Chiaramonte, Francis P.; Davidian, Kenneth J.

1990-01-01

A variable gravity research facility named 'Newton' was designed by 58 students from 13 countries at the International Space University's 1989 summer session at the Universite Louis Pasteur, Strasbourge, France. The project was comprehensive in scope, including a political and legal foundation for international cooperation, development and financing; technical, science and engineering issues; architectural design; plausible schedules; and operations, crew issues and maintenance. Since log-term exposure to zero gravity is known to be harmful to the human body, the main goal was to design a unique variable gravity research facility which would find a practical solution to this problem, permitting a manned mission to Mars. The facility would not duplicate other space-based facilities and would provide the flexibility for examining a number of gravity levels, including lunar and Martian gravities. Major design alternatives included a truss versus a tether based system which also involved the question of docking while spinning or despinning to dock. These design issues are described. The relative advantages or disadvantages are discussed, including comments on the necessary research and technology development required for each.

Environmental Conditions and Seasonal Variables in American Youth Football Leagues.

PubMed

Yeargin, Susan W; Cahoon, Erin; Hosokawa, Yuri; Mensch, James M; Dompier, Thomas P; Kerr, Zachary Y

2017-11-01

Our study describes youth football (YFB) environmental conditions and the associated heat index (HI) risk category. An observational research design was utilized. Independent variables included month, time, event, and geographic location. Main outcome variables were frequency of events, average HI, and corresponding risk categorization. The HI was recorded with the day and time for each YFB event across 2 YFB seasons. Nearly half (49.8%) of events were in a high HI risk category and 20.0% should have been cancelled. The hottest HI values were recorded in July and August (83.2 ± 9.4°F to 87.2 ± 10.9°F; 24.0% of YFB events). The 7 to 10 am time frame was cooler (67.7 ± 14.5°F; 6.3% of YFB events) than other time frames ( P < .001). Hotter HI values were recorded in practices versus games (75.9 ± 14.1°F vs 70.6 ± 14.6°F; t = -6.426, P < .001). Starting the YFB season in September and holding weekend events in the early morning hours can decrease exposure to environmental heat stress.

Air pollution and heart rate variability: effect modification by chronic lead exposure.

PubMed

Park, Sung Kyun; O'Neill, Marie S; Vokonas, Pantel S; Sparrow, David; Wright, Robert O; Coull, Brent; Nie, Huiling; Hu, Howard; Schwartz, Joel

2008-01-01

Outdoor air pollution and lead exposure can disturb cardiac autonomic function, but the effects of both these exposures together have not been studied. We examined whether higher cumulative lead exposures, as measured by bone lead, modified cross-sectional associations between air pollution and heart rate variability among 384 elderly men from the Normative Aging Study. We used linear regression, controlling for clinical, demographic, and environmental covariates. We found graded, significant reductions in both high-frequency and low-frequency powers of heart rate variability in relation to ozone and sulfate across the quartiles of tibia lead. Interquartile range increases in ozone and sulfate were associated respectively, with 38% decrease (95% confidence interval = -54.6% to -14.9%) and 22% decrease (-40.4% to 1.6%) in high frequency, and 38% decrease (-51.9% to -20.4%) and 12% decrease (-28.6% to 9.3%) in low frequency, in the highest quartile of tibia lead after controlling for potential confounders. We observed similar but weaker effect modification by tibia lead adjusted for education and cumulative traffic (residuals of the regression of tibia lead on education and cumulative traffic). Patella lead modified only the ozone effect on heart rate variability. People with long-term exposure to higher levels of lead may be more sensitive to cardiac autonomic dysfunction on high air pollution days. Efforts to understand how environmental exposures affect the health of an aging population should consider both current levels of pollution and history of lead exposure as susceptibility factors.

Association of Diet With Skin Histological Features in UV-B–Exposed Mice

PubMed Central

Hsia, Yvonne; Weeks, David M.; Dixon, Tatiana K.; Lepe, Jessica; Thomas, J. Regan

2017-01-01

Importance Long-term exposure to solar radiation produces deleterious photoaging of the skin. It is not known if diet can influence skin photoaging. Objectives To study the influence of a calorie-restricted diet and an obesity diet in mice exposed to long-term UV-B irradiation to assess if there is an association between diet and histopathological response to UV-B irradiation. Design, Setting, and Participants In this animal model study in an academic setting, the dorsal skin of SKH1 hairless mice receiving normal, calorie-restricted, and obesity diets was exposed to UV-B irradiation 3 times a week for 10 weeks and were compared with corresponding controls. The mice were placed in the following groups, with 8 animals in each group: (1) intact control (C) with regular diet and no UV-B exposure, (2) intact control with UV-B exposure (CR), (3) calorie-restricted diet (CrC), (4) calorie-restricted diet with UV-B exposure (CrR), (5) obesity diet (OC), and (6) obesity diet with UV-B exposure (OR). The experiment was conducted during October through December 2013. Tissue processing and histological analysis were completed in 2016. Main Outcomes and Measures Histomorphometric analysis was performed on paraffin-embedded skin sections stained by histological and immunohistochemical methods for estimation of epidermal thickness, epidermal proliferating cell nuclear antigen index, collagen I, elastic fibers, fibroblasts, mast cells, dermal cellularity, and adipose layer ratio. Changes in wrinkles were noted. Results Hairless female mice (age range, 6-8 weeks) were obtained. With a normal diet, changes from UV-B irradiation occurred in epidermal thickness, epidermal proliferating cell nuclear antigen index, collagen I, elastic fibers, fibroblasts, and mast cells, which were modestly influenced by an obesity diet. Calorie restriction influenced the skin in nonirradiated control animals, with higher values for most variables. After UV-B exposure in animals with calorie restriction, epidermal thickness was increased, but other variables were unaffected. Animals receiving the calorie-restricted diet lost weight when exposed to long-term UV-B irradiation. Wrinkles were reduced in the calorie-restricted control group and in UV-B–exposed animals who received the obesity diet. Conclusions and Relevance Dietary alterations seem to modify histopathological responses to UV-B exposure in the skin of hairless mice. Level of Evidence NA. PMID:28418519

Within- and between-child variation in repeated urinary pesticide metabolite measurements over a 1-year period.

PubMed

Attfield, Kathleen R; Hughes, Michael D; Spengler, John D; Lu, Chensheng

2014-02-01

Children are exposed to pesticides from many sources and routes, including dietary and incidental ingestion, dermal absorption, and inhalation. Linking health outcomes to these exposures using urinary metabolites requires understanding temporal variability within subjects to avoid exposure misclassification. We characterized the within- and between-child variability of urinary organophosphorus and pyrethroid metabolites in 23 participants of the Children's Pesticide Exposure Study-Washington over 1 year and examined the ability of one to four spot urine samples to categorize mean exposures. Each child provided urine samples twice daily over 7- to 16-day sessions in four seasons in 2003 and 2004. Samples were analyzed for five pyrethroid and five organophosphorus (OP) metabolites. After adjusting for specific gravity, we used a customized maximum likelihood estimation linear mixed-effects model that accounted for values below the limit of detection to calculate intraclass correlation coefficients (ICC) and conducted surrogate category analyses. Within-child variability was 2-11 times greater than between-child variability. When restricted to samples collected during a single season, ICCs were higher in the fall, winter, and spring than in summer for OPs, and higher in summer and winter for pyrethroids, indicating an increase in between-person variability relative to within-person variability during these seasons. Surrogate category analyses demonstrated that a single spot urine sample did not categorize metabolite concentrations well, and that four or more samples would be needed to categorize children into quartiles consistently. Urinary biomarkers of these short half-life pesticides exhibited substantial within-person variability in children observed over four seasons. Researchers investigating pesticides and health outcomes in children may need repeated biomarker measurements to derive accurate estimates of exposure and relative risks.

Posttraumatic stress symptoms as a mediating factor on the effects of exposure to community violence among children in Cape Town, South Africa.

PubMed

Shields, Nancy; Nadasen, Kathy; Pierce, Lois

2009-01-01

Research conducted over the past 20 years has linked exposure to violence to posttraumatic stress disorder (PTSD) in children both in the United States and South Africa, but very little research has investigated PTSD as a mediating variable between exposure to violence and other problems. The purpose of the current research was to determine if PTSD acts as a mediating variable between exposure to violence and depression, and exposure to violence and aggressive and violent behavior at school among a sample of 247 South African children. Regression analysis suggested that PTSD mediated the effects of exposure to violence on depression, whereas the effect of exposure to violence on aggression and violent behavior was only direct. The findings are discussed in terms of their implications for intervention and treatment.

Statistical grand rounds: understanding the mechanism: mediation analysis in randomized and nonrandomized studies.

PubMed

Mascha, Edward J; Dalton, Jarrod E; Kurz, Andrea; Saager, Leif

2013-10-01

In comparative clinical studies, a common goal is to assess whether an exposure, or intervention, affects the outcome of interest. However, just as important is to understand the mechanism(s) for how the intervention affects outcome. For example, if preoperative anemia was shown to increase the risk of postoperative complications by 15%, it would be important to quantify how much of that effect was due to patients receiving intraoperative transfusions. Mediation analysis attempts to quantify how much, if any, of the effect of an intervention on outcome goes though prespecified mediator, or "mechanism" variable(s), that is, variables sitting on the causal pathway between exposure and outcome. Effects of an exposure on outcome can thus be divided into direct and indirect, or mediated, effects. Mediation is claimed when 2 conditions are true: the exposure affects the mediator and the mediator (adjusting for the exposure) affects the outcome. Understanding how an intervention affects outcome can validate or invalidate one's original hypothesis and also facilitate further research to modify the responsible factors, and thus improve patient outcome. We discuss the proper design and analysis of studies investigating mediation, including the importance of distinguishing mediator variables from confounding variables, the challenge of identifying potential mediators when the exposure is chronic versus acute, and the requirements for claiming mediation. Simple designs are considered, as well as those containing multiple mediators, multiple outcomes, and mixed data types. Methods are illustrated with data collected by the National Surgical Quality Improvement Project (NSQIP) and utilized in a companion paper which assessed the effects of preoperative anemic status on postoperative outcomes.

Assessment of Population and Microenvironmental Exposure to Fine Particulate Matter (PM2.5)

NASA Astrophysics Data System (ADS)

Jiao, Wan

A positive relationship exists between fine particulate matter (PM 2.5) exposure and adverse health effects. PM2.5 concentration-response functions used in the quantitative risk assessment were based on findings from human epidemiological studies that relied on areawide ambient concentrations as surrogate for actual ambient exposure, which cannot capture the spatial and temporal variability in human exposures. The goal of the study is to assess inter-individual, geographic and seasonal variability in population exposures to inform the interpretation of available epidemiological studies, and to improve the understanding of how exposure-related factors in important exposure microenvironments contribute to the variability in individual PM2.5 exposure. Typically, the largest percentage of time in which an individual is exposed to PM2.5 of ambient origin occurs in indoor residence, and the highest ambient PM2.5 concentrations occur in transportation microenvironments because of the proximity to on-road traffic emissions. Therefore, indoor residence and traffic-related transportation microenvironments were selected for further assessment in the study. Population distributions of individual daily PM2.5 exposures were estimated for the selected regions and seasons using the Stochastic Human Exposure and Dose Simulation Model for Particulate Matter (SHEDS-PM). For the indoor residence, the current practice by assuming the entire residence to be one large single zone for calculating the indoor residential PM 2.5 concentration was evaluated by applying an indoor air quality model, RISK, to compare indoor PM2.5 concentrations between single-zone and multi-zone scenarios. For the transportation microenvironments, one field data collection focused on in-vehicle microenvironment and was conducted to quantify the variability in the in-vehicle PM2.5 concentration with respect to the outside vehicle concentration for a wide range of conditions that affect intra-vehicle variability in exposure concentration, including ventilation air source, window status, fan setting, AC utilization, vehicle speed, road type, travel direction, and time of day. Another field data collection measured PM2.5 exposure concentrations on pre-selected routes across transportation modes of pedestrian, bus, and car to quantify the variability in the transportation mode concentration ratios, and identify factors affecting variability in traffic-related concentrations. In general, population daily average exposure to ambient PM2.5 is less than the ambient concentration by approximately half. The ratio of PM2.5 ambient exposure to ambient concentration (Ea/C) varies by individual, geographic area and season, as a result of regional differences in housing stock and seasonal differences in air exchange rates (ACH). For the indoor residence, the single-zone assumption is biased when any non-ambient source is presented. Bias correction factors are developed for cooking and smoking scenarios, separately, to improve the concentration estimates. Correction factors are most sensitive to changes in ACH but relatively insensitive to variations in source emission rate and duration. In a SHEDS-PM case study, the population daily average total exposure increased by 17% after applying correction factors. Transportation mode exposure concentrations are sensitive to mode, and are affected by factors such as vehicle ventilation and proximity to on-road emission sources. The in-vehicle to outside vehicle concentration (I/O) ratio is highly sensitive to whether windows are open or, for closed windows, to whether fresh air or recirculating air is used. Both model simulations and field studies are needed to inform better understanding of human exposure. Exposure, and not just concentration, should be considered in developing risk management strategies to reduce uncertainty in health effect estimates, and to identify highly exposed groups and possible exposure reduction strategies.

Swift X-ray monitoring of stellar coronal variability

NASA Astrophysics Data System (ADS)

Miller, Brendan; Hagen, Cedric; Gallo, Elena; Wright, Jason T.

2018-01-01

We used California Planet Search Ca II H and K core emission measurements to identify and characterize chromospheric activity cycles in a sample of main-sequence FGK stars. About a dozen of these with existing ROSAT archival data were targeted with Swift to obtain a current epoch X-ray flux. We find that coronal variability by a factor of several is common on decade-long timescales (we attempt to link to the chromospheric cycle phase) but can also occur on short timescales between Swift visits to a given target, presumably related to stellar rotation and coronal inhomogeneity or to small flares. Additionally, we present new Swift monitoring observations of two M dwarfs with known exoplanets: GJ 15A and GJ 674. GJ 15A b is around 5.3 Earth masses with an 11.4 day orbital period, while GJ 674 is around 11.1 Earth masses with a 4.7 day orbital period. GJ 15A was observed several times in late 2014 and then monitored at approximately weekly intervals for several months in early 2016, for a total exposure of 18 ks. GJ 674 was monitored at approximately weekly intervals for most of 2016, for a total exposure of 40 ks. We provide light curves and hardness ratios for both sources, and also compare to earlier archival X-ray data. Both sources show significant X-ray variability, including between consecutive observations. We quantify the energy distribution for coronal flaring, and compare to optical results for M dwarfs from Kepler. Finally, we discuss the implications of M dwarf coronal activity for exoplanets orbiting within the nominal habitable zone.

Swift X-ray monitoring of stellar coronal variability

NASA Astrophysics Data System (ADS)

Miller, Brendan P.; Gallo, Elena; Wright, Jason; Hagen, Cedric

2017-08-01

We used California Planet Search Ca II H and K core emission measurements to identify and characterize chromospheric activity cycles in a sample of main-sequence FGK stars. About a dozen of these with existing ROSAT archival data were targeted with Swift to obtain a current epoch X-ray flux. We find that coronal variability by a factor of several is common on decade-long timescales (we attempt to link to the chromospheric cycle phase) but can also occur on short timescales between Swift visits to a given target, presumably related to stellar rotation and coronal inhomogeneity or to small flares.Additionally, we present new Swift monitoring observations of two M dwarfs with known exoplanets: GJ 15A and GJ 674. GJ 15A b is around 5.3 Earth masses with an 11.4 day orbital period, while GJ 674 is around 11.1 Earth masses with a 4.7 day orbital period. GJ 15A was observed several times in late 2014 and then monitored at approximately weekly intervals for several months in early 2016, for a total exposure of 18 ks. GJ 674 was monitored at approximately weekly intervals for most of 2016, for a total exposure of 40 ks. We provide light curves and hardness ratios for both sources, and also compare to earlier archival X-ray data. Both sources show significant X-ray variability, including between consecutive observations. We quantify the energy distribution for coronal flaring, and compare to optical results for M dwarfs from Kepler. Finally, we discuss the implications of M dwarf coronal activity for exoplanets orbiting within the nominal habitable zone.

Personal Exposure to Inhalable Dust and the Specific Latex Aero-Allergen, Hev b6.02, in Latex Glove Manufacturing in Thailand

PubMed Central

Sanguanchaiyakrit, Nuthchyawach; Povey, Andrew C.; de Vocht, Frank

2014-01-01

Objectives: Latex product manufacturing is an important industry in south-east Asia but has the potential for considerable occupational exposure of workers to latex allergens. Although exposure to latex allergens can result in adverse health reactions, few studies to characterize this exposure have been conducted to date. This study therefore aimed to characterize current airborne inhalable dust and the specific allergen, Hev b 6.02, exposures in this industry in Thailand. Methods: Workers were recruited from three factories in the southern part of Thailand. Full-shift inhalable dust personal air sampling was conducted using IOM sampling heads equipped with polytetrafluoroethylene filters at a 2.0 l min−1 flowrate. After weighing to determine inhalable dust levels, filters were extracted and analysed for Hev b 6.02 using an enzyme immunometric assay. Results: Two hundred and seventy-five workers agreed to participate, resulting in a total of 292 measurements. Geometric mean (GM) personal exposure to inhalable dust was 0.88mg m–3, but individual exposures up to 12.34mg m–3 were measured. The pattern of exposure was similar across factories, with highest exposures in the stripping (GM 2.08–4.05mg m–3 for the 3 factories) and tumbling departments (1.11–2.17mg m–3). Within-worker (day-to-day) variability contributed 92% to total variability. The Hev b 6.02 exposure pattern was similar with time-weighted average GM exposure levels in the oldest factory ranging from 8.7mg m–3 in the laboratory to 30.2mg m–3 in the stripping department. In contrast to inhalable dust exposure, total exposure variability was primary driven by variability between workers (67%). Conclusions: Workers in these latex product factories get routinely exposed to measurable Hev b 6.02 levels, which may give rise to increased incidence of allergic symptoms and occupational asthma. Also, in this measurement campaign a 10mg m–3, but not 15mg m–3, occupational exposure limit for inhalable dust was occasionally exceeded. Highest Hev b 6.02 exposures were found in the stripping and tumbling departments, which would be natural targets for interventions aimed at reducing exposure. PMID:24569810

Personal exposure to inhalable dust and the specific latex aero-allergen, Hev b6.02, in latex glove manufacturing in Thailand.

PubMed

Sanguanchaiyakrit, Nuthchyawach; Povey, Andrew C; de Vocht, Frank

2014-06-01

Latex product manufacturing is an important industry in south-east Asia but has the potential for considerable occupational exposure of workers to latex allergens. Although exposure to latex allergens can result in adverse health reactions, few studies to characterize this exposure have been conducted to date. This study therefore aimed to characterize current airborne inhalable dust and the specific allergen, Hev b 6.02, exposures in this industry in Thailand. Workers were recruited from three factories in the southern part of Thailand. Full-shift inhalable dust personal air sampling was conducted using IOM sampling heads equipped with polytetrafluoroethylene filters at a 2.0 l min(-1) flowrate. After weighing to determine inhalable dust levels, filters were extracted and analysed for Hev b 6.02 using an enzyme immunometric assay. Two hundred and seventy-five workers agreed to participate, resulting in a total of 292 measurements. Geometric mean (GM) personal exposure to inhalable dust was 0.88 mg m(-3), but individual exposures up to 12.34 mg m(-3) were measured. The pattern of exposure was similar across factories, with highest exposures in the stripping (GM 2.08-4.05 mg m(-3) for the 3 factories) and tumbling departments (1.11-2.17 mg m(-3)). Within-worker (day-to-day) variability contributed 92% to total variability. The Hev b 6.02 exposure pattern was similar with time-weighted average GM exposure levels in the oldest factory ranging from 8.7 mg m(-3) in the laboratory to 30.2mg m(-3) in the stripping department. In contrast to inhalable dust exposure, total exposure variability was primary driven by variability between workers (67%). Workers in these latex product factories get routinely exposed to measurable Hev b 6.02 levels, which may give rise to increased incidence of allergic symptoms and occupational asthma. Also, in this measurement campaign a 10mg m(-3), but not 15 mg m(-3), occupational exposure limit for inhalable dust was occasionally exceeded. Highest Hev b 6.02 exposures were found in the stripping and tumbling departments, which would be natural targets for interventions aimed at reducing exposure. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

A case-control study to investigate the risk of leukaemia associated with exposure to benzene in petroleum marketing and distribution workers in the United Kingdom.

PubMed Central

Rushton, L; Romaniuk, H

1997-01-01

OBJECTIVES: To investigate the risk of leukaemia in workers in the petroleum distribution industry who were exposed to low levels of benzene. METHODS: From the cohort of distribution workers, 91 cases were identified as having leukaemia on either a death certificate or on cancer registration. These cases were compared with controls (four per case) randomly selected from the cohort, who were from the same company as the respective case, matched for age, and alive and under follow up at the time of case occurrence. Work histories were collected for the cases and controls, together with information about the terminals at which they had worked, fuel compositions, and occupational hygiene measurements of benzene. These data were used to derive quantitative estimates of personal exposure to benzene. Odds ratios (OR) were calculated conditional on the matching, to identify those variables in the study which were associated with risk of leukaemia. Examination of the potential effects of confounding and other variables was carried out with conditional logistic regression. Analyses were carried out for all leukaemia and separately for acute lymphoblastic, chronic lymphocytic, acute myeloid and monocytic, and chronic myeloid leukaemias. RESULTS: There was no significant increase in the overall risk of all leukaemias with higher cumulative exposure to benzene or with intensity of exposure, but risk was consistently doubled in subjects employed in the industry for > 10 years. Acute lymphoblastic leukaemia tended to occur in workers employed after 1950, who started work after the age of 30, worked for a short duration, and experienced low cumulative exposure with few peaks. The ORs did not increase with increasing cumulative exposure. The risk of chronic lymphocytic leukaemia seemed to be related most closely to duration of employment and the highest risk occurred in white collar workers with long service. These workers had only background levels of benzene exposure. There was no evidence of an association of risk with any exposure variables, and no evidence of an increasing risk with increasing cumulative exposure, mean intensity, or maximum intensity of exposure. The patterns of risk for acute myeloid and monocytic leukaemia were different from those of the lymphoid subgroups, in which duration of employment was the variable most closely related to risk. Risk was increased to an OR of 2.8 (95% confidence interval (95% CI) 0.8 to 9.4) for a cumulative exposure between 4.5 and 45 ppm-years compared with < 0.45 ppm-years. For mean intensity between 0.2 and 0.4 ppm an OR of 2.8 (95% CI 0.9 to 8.5) was found compared with < 0.02 ppm. Risk did not increase with cumulative exposure, maximum intensity, or mean intensity of exposure when treated as continuous variables. Cases of acute myeloid and monocytic leukaemia were more often classified as having peaked exposures than controls, and when variables characterising peaks, particularly daily and weekly peaks, were included in the analysis these tended to dominate the other exposure variables. However, because of the small numbers it is not possible to distinguish the relative influence of peaked and unpeaked exposures on risk of acute myeloid and monocytic leukaemia. There was no evidence of an increased risk of chronic myeloid leukaemia with increases in cumulative exposure, maximum intensity, mean intensity, and duration of employment, either as continuous or categorical variables. Analyses exploring the sensitivity of the results to the source and quality of the work histories showed similar patterns in general. However, no increases in ORs for categories of cumulative exposure were found for acute myeloid and monocytic leukaemia in the data set which included work histories obtained from personnel records still in existence, although numbers were reduced. Analyses excluding the last five and 10 years of exposure showed a tendency for ORs to reduce for chronic lymphocytic leukaemia and chronic myeloid leukaemia, and to increase for acute myeloid and monocytic leukaemia. Limitations of the study include uncertainties and gaps in the information collected, and small numbers in subcategories of exposure which can lead to wide CIs around the risk estimates and poor fit of the mathematical models. CONCLUSIONS: There is no evidence in this study of an association between exposure to benzene and lymphoid leukaemia, either acute or chronic. There is some suggestion of a relation between exposure to benzene and myeloid leukaemia, in particular for acute myeloid and monocytic leukaemia. Peaked exposures seemed to be experienced for this disease. However, in view of the limitations of the study, doubt remains as to whether the risk of acute myeloid and monocytic leukaemia is increased by cumulative exposures of < 45 ppm-years. Further work is recommended to review the work histories and redefine their quality, to explore the discrepancies between results for categorical and continuous variables, and to develop ranges around the expose estimates to enable further sensitivity analyses to be carried out. PMID:9155776

Animal models of chronic obstructive pulmonary disease.

PubMed

Pérez-Rial, Sandra; Girón-Martínez, Álvaro; Peces-Barba, Germán

2015-03-01

Animal models of disease have always been welcomed by the scientific community because they provide an approach to the investigation of certain aspects of the disease in question. Animal models of COPD cannot reproduce the heterogeneity of the disease and usually only manage to represent the disease in its milder stages. Moreover, airflow obstruction, the variable that determines patient diagnosis, not always taken into account in the models. For this reason, models have focused on the development of emphysema, easily detectable by lung morphometry, and have disregarded other components of the disease, such as airway injury or associated vascular changes. Continuous, long-term exposure to cigarette smoke is considered the main risk factor for this disease, justifying the fact that the cigarette smoke exposure model is the most widely used. Some variations on this basic model, related to exposure time, the association of other inducers or inhibitors, exacerbations or the use of transgenic animals to facilitate the identification of pathogenic pathways have been developed. Some variations or heterogeneity of this disease, then, can be reproduced and models can be designed for resolving researchers' questions on disease identification or treatment responses. Copyright © 2014 SEPAR. Published by Elsevier Espana. All rights reserved.

Controlling dust from concrete saw cutting.

PubMed

Shepherd, Susan; Woskie, Susan

2013-01-01

Cutting concrete with gas-powered saws is ubiquitous in the construction industry and a source of exposure to respirable crystalline silica. Volunteers from the New England Laborers Training Center were recruited to participate in a field experiment examining dust reductions through the use of water, from a hose and from a sprayer, as a dust control. In four series of tests, reinforced concrete pipe was cut under both "dry" and "wet" control conditions. Overall, the geometric mean respirable dust concentration for "dry" cutting (14.396 mg/m³) exceeded both types of water-based controls by more than tenfold. Wet cutting reduced the respirable dust concentration by 85% compared with dry cutting when comparing tests paired by person and saw blade (n = 79 pairs). Using a respirable cyclone, a total of 178 samples were taken. Due to the high variability in dust exposure found in this and other studies of saw cutting, the data were examined for potential exposure determinants that contribute to that variability. Using mixed models, three fixed effects were statistically significant: control condition, worker experience, and location. A random effect for subject was included in the model to account for repeated measures. When each of the significant fixed effects was included with the random effect, it was apparent that inclusion of worker experience or location reduced the between-worker component of exposure variability, while inclusion of control condition (wet vs. dry) explained a large portion of the within-subject variability. Overall, the fixed effect variable for control condition explained the largest fraction of the total exposure variability.

Silica exposure during construction activities: statistical modeling of task-based measurements from the literature.

PubMed

Sauvé, Jean-François; Beaudry, Charles; Bégin, Denis; Dion, Chantal; Gérin, Michel; Lavoué, Jérôme

2013-05-01

Many construction activities can put workers at risk of breathing silica containing dusts, and there is an important body of literature documenting exposure levels using a task-based strategy. In this study, statistical modeling was used to analyze a data set containing 1466 task-based, personal respirable crystalline silica (RCS) measurements gathered from 46 sources to estimate exposure levels during construction tasks and the effects of determinants of exposure. Monte-Carlo simulation was used to recreate individual exposures from summary parameters, and the statistical modeling involved multimodel inference with Tobit models containing combinations of the following exposure variables: sampling year, sampling duration, construction sector, project type, workspace, ventilation, and controls. Exposure levels by task were predicted based on the median reported duration by activity, the year 1998, absence of source control methods, and an equal distribution of the other determinants of exposure. The model containing all the variables explained 60% of the variability and was identified as the best approximating model. Of the 27 tasks contained in the data set, abrasive blasting, masonry chipping, scabbling concrete, tuck pointing, and tunnel boring had estimated geometric means above 0.1mg m(-3) based on the exposure scenario developed. Water-fed tools and local exhaust ventilation were associated with a reduction of 71 and 69% in exposure levels compared with no controls, respectively. The predictive model developed can be used to estimate RCS concentrations for many construction activities in a wide range of circumstances.

Assessment of extremely low frequency magnetic field exposure from GSM mobile phones.

PubMed

Calderón, Carolina; Addison, Darren; Mee, Terry; Findlay, Richard; Maslanyj, Myron; Conil, Emmanuelle; Kromhout, Hans; Lee, Ae-kyoung; Sim, Malcolm R; Taki, Masao; Varsier, Nadège; Wiart, Joe; Cardis, Elisabeth

2014-04-01

Although radio frequency (RF) electromagnetic fields emitted by mobile phones have received much attention, relatively little is known about the extremely low frequency (ELF) magnetic fields emitted by phones. This paper summarises ELF magnetic flux density measurements on global system for mobile communications (GSM) mobile phones, conducted as part of the MOBI-KIDS epidemiological study. The main challenge is to identify a small number of generic phone models that can be used to classify the ELF exposure for the different phones reported in the study. Two-dimensional magnetic flux density measurements were performed on 47 GSM mobile phones at a distance of 25 mm. Maximum resultant magnetic flux density values at 217 Hz had a geometric mean of 221 (+198/-104) nT. Taking into account harmonic data, measurements suggest that mobile phones could make a substantial contribution to ELF exposure in the general population. The maximum values and easily available variables were poorly correlated. However, three groups could be defined on the basis of field pattern indicating that manufacturers and shapes of mobile phones may be the important parameters linked to the spatial characteristics of the magnetic field, and the categorization of ELF magnetic field exposure for GSM phones in the MOBI-KIDS study may be achievable on the basis of a small number of representative phones. Such categorization would result in a twofold exposure gradient between high and low exposure based on type of phone used, although there was overlap in the grouping. © 2013 Wiley Periodicals, Inc.

Drinking-water exposure to a mixture of nitrate and low-dose atrazine metabolites and small-for-gestational age (SGA) babies: a historic cohort study.

PubMed

Migeot, V; Albouy-Llaty, M; Carles, C; Limousi, F; Strezlec, S; Dupuis, A; Rabouan, S

2013-04-01

Groundwater, surface water and drinking water are contaminated by nitrates and atrazine, an herbicide. They are present as a mixture in drinking water and with their endocrine-disrupting activity, they may alter fetal growth. To study an association between drinking-water atrazine metabolites/nitrate mixture exposure and small-for-gestational-age(SGA). A historic cohort study based on birth records and drinking-water nitrate and pesticide measurements in Deux-Sèvres (France) between 2005 and 2009 was carried out. Exposure to drinking-water atrazine metabolites/nitrate mixture was divided into 6 classes according to the presence or absence of atrazine metabolites and to terciles of nitrate concentrations in each trimester of pregnancy. Regression analysis of SGA by mixture exposure at second trimester was subsequently conducted. We included 11,446 woman-neonate couples of whom 37.0% were exposed to pesticides, while 99.9% of the women were exposed to nitrates. Average nitrate concentration was from 0 to 63.30 mg/L. In the second trimester of pregnancy, the risk of SGA was different with mixture exposure when drinking-water atrazine metabolites, mainly 2 hydroxyatrazine and desethylatrazine, were present and nitrate dose exposure increased: compared to single first tercile of nitrate concentration exposure, single second tercile exposure OR was 1.74 CI 95% [1.10; 2.75] and atrazine metabolites presence in the third tercile of nitrate concentration exposure OR was 0.87 CI 95% [0.45;1.67]. It is possible that the association found at the second trimester of exposure with regard to birth weight may likewise be observed before birth, with regard to the estimated fetal weight, and that it might change in the event that the atrazine metabolites dose were higher or the nitrate dose lower. It would appear necessary to further explore the variability of effects. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Occupational Exposure to Diesel Particulate Matter in Municipal Household Waste Workers.

PubMed

Lee, Kyong-Hui; Jung, Hye-Jung; Park, Dong-Uk; Ryu, Seung-Hun; Kim, Boowook; Ha, Kwon-Chul; Kim, Seungwon; Yi, Gwangyong; Yoon, Chungsik

2015-01-01

The purposes of this study were to determine the following: 1) the exposure levels of municipal household waste (MHW) workers to diesel particulate matter (DPM) using elemental carbon (EC), organic carbon (OC), total carbon (TC), black carbon (BC), and fine particulate matter (PM 2.5) as indicators; 2) the correlations among the indicators; 3) the optimal indicator for DPM; and 4) factors that influence personal exposure to DPM. A total of 72 workers in five MHW collection companies were assessed over a period of 7 days from June to September 2014. Respirable EC/OC samples were quantified using the thermal optical transmittance method. BC and PM 2.5 were measured using real-time monitors, an aethalometer and a laser photometer. All results were statistically analyzed for occupational and environmental variables to identify the exposure determinants of DPM. The geometric mean of EC, OC, TC, BC and PM 2.5 concentrations were 4.8, 39.6, 44.8, 9.1 and 62.0 μg/m3, respectively. EC concentrations were significantly correlated with the concentrations of OC, TC and BC, but not with those of PM 2.5. The exposures of the MHW collectors to EC, OC, and TC were higher than those of the drivers (p<0.05). Workers of trucks meeting Euro 3 emission standard had higher exposures to EC, OC, TC and PM 2.5 than those working on Euro 4 trucks (p<0.05). Multiple regression analysis revealed that the job task, European engine emission standard, and average driving speed were the most influential factors in determining worker exposure. We assessed MHW workers' exposure to DPM using parallel sampling of five possible indicators. Of these five indicators, EC was shown to be the most useful indicator of DPM exposure for MHW workers, and the job task, European emission standard, and average driving speed were the main determinants of EC exposure.

Short daily exposure to hand-arm vibrations in Swedish car mechanics.

PubMed

Barregård, Lars

2003-01-01

The aim of the study was to examine the daily exposure times to hand-arm vibrations in Swedish car mechanics, to test a method for estimating the exposure time without observing the workers for whole days, and to use the results for predicting the prevalence of vibration-induced white fingers (VWF) by the ISO 5349-model. Six garages were surveyed. In each garage, 5-10 car mechanics were observed in random order every 30 seconds throughout working days. The daily exposure time for each mechanic was estimated from the fraction of the observations that the mechanic was exposed. A total of 51 mechanics were observed, most of them on two different working days, yielding estimates for 95 days. The median effective exposure time was 10 minutes per day (95% confidence interval 5-15 minutes, arithmetic mean 14 minutes, maximum 80 minutes), and most of the exposure time was attributable to fastening and loosening nuts. The within-worker and between-worker variability was high (total sigma2 0.99, geometric standard deviation of 2.7). Using the observed exposure time and data on vibration levels of the main tools in Swedish car mechanics (average weighted acceleration level of 3.5 m/s2), the model in ISO-standard 5349 would predict that only three percent of the car mechanics will suffer from VWF after 20 years of exposure. In contrast, a recent survey of VWF showed the prevalence to be 25 percent. The precision of the observation method was estimated and was found to be good for the group daily mean. On the individual level the precision was only acceptable if the daily exposure time was > or = 40 minutes. In conclusion, the daily exposure time was short and the vibration level was limited. Nevertheless, hand-arm vibrations cause VWF in a significant number of car mechanics. The method of observing workers intermittently seemed to work well.

Occupational Exposure to Diesel Particulate Matter in Municipal Household Waste Workers

PubMed Central

Lee, Kyong-Hui; Jung, Hye-Jung; Park, Dong-Uk; Ryu, Seung-Hun; Kim, Boowook; Ha, Kwon-Chul; Kim, Seungwon; Yi, Gwangyong; Yoon, Chungsik

2015-01-01

Objective The purposes of this study were to determine the following: 1) the exposure levels of municipal household waste (MHW) workers to diesel particulate matter (DPM) using elemental carbon (EC), organic carbon (OC), total carbon (TC), black carbon (BC), and fine particulate matter (PM 2.5) as indicators; 2) the correlations among the indicators; 3) the optimal indicator for DPM; and 4) factors that influence personal exposure to DPM. Methods A total of 72 workers in five MHW collection companies were assessed over a period of 7 days from June to September 2014. Respirable EC/OC samples were quantified using the thermal optical transmittance method. BC and PM 2.5 were measured using real-time monitors, an aethalometer and a laser photometer. All results were statistically analyzed for occupational and environmental variables to identify the exposure determinants of DPM. Results The geometric mean of EC, OC, TC, BC and PM 2.5 concentrations were 4.8, 39.6, 44.8, 9.1 and 62.0 μg/m3, respectively. EC concentrations were significantly correlated with the concentrations of OC, TC and BC, but not with those of PM 2.5. The exposures of the MHW collectors to EC, OC, and TC were higher than those of the drivers (p<0.05). Workers of trucks meeting Euro 3 emission standard had higher exposures to EC, OC, TC and PM 2.5 than those working on Euro 4 trucks (p<0.05). Multiple regression analysis revealed that the job task, European engine emission standard, and average driving speed were the most influential factors in determining worker exposure. Conclusions We assessed MHW workers’ exposure to DPM using parallel sampling of five possible indicators. Of these five indicators, EC was shown to be the most useful indicator of DPM exposure for MHW workers, and the job task, European emission standard, and average driving speed were the main determinants of EC exposure. PMID:26248196

Local- and regional-scale air pollution modelling (PM10) and exposure assessment for pregnancy trimesters, infancy, and childhood to age 15 years: Avon Longitudinal Study of Parents And Children (ALSPAC).

PubMed

Gulliver, John; Elliott, Paul; Henderson, John; Hansell, Anna L; Vienneau, Danielle; Cai, Yutong; McCrea, Adrienne; Garwood, Kevin; Boyd, Andy; Neal, Lucy; Agnew, Paul; Fecht, Daniela; Briggs, David; de Hoogh, Kees

2018-04-01

We established air pollution modelling to study particle (PM 10 ) exposures during pregnancy and infancy (1990-1993) through childhood and adolescence up to age ~15 years (1991-2008) for the Avon Longitudinal Study of Parents And Children (ALSPAC) birth cohort. For pregnancy trimesters and infancy (birth to 6 months; 7 to 12 months) we used local (ADMS-Urban) and regional/long-range (NAME-III) air pollution models, with a model constant for local, non-anthropogenic sources. For longer exposure periods (annually and the average of birth to age ~8 and to age ~15 years to coincide with relevant follow-up clinics) we assessed spatial contrasts in local sources of PM 10 with a yearly-varying concentration for all background sources. We modelled PM 10 (μg/m 3 ) for 36,986 address locations over 19 years and then accounted for changes in address in calculating exposures for different periods: trimesters/infancy (n = 11,929); each year of life to age ~15 (n = 10,383). Intra-subject exposure contrasts were largest between pregnancy trimesters (5 th to 95 th centile: 24.4-37.3 μg/m 3 ) and mostly related to temporal variability in regional/long-range PM 10 . PM 10 exposures fell on average by 11.6 μg/m 3 from first year of life (mean concentration = 31.2 μg/m 3 ) to age ~15 (mean = 19.6 μg/m 3 ), and 5.4 μg/m 3 between follow-up clinics (age ~8 to age ~15). Spatial contrasts in 8-year average PM 10 exposures (5 th to 95 th centile) were relatively low: 25.4-30.0 μg/m 3 to age ~8 years and 20.7-23.9 μg/m 3 from age ~8 to age ~15 years. The contribution of local sources to total PM 10 was 18.5%-19.5% during pregnancy and infancy, and 14.4%-17.0% for periods leading up to follow-up clinics. Main roads within the study area contributed on average ~3.0% to total PM 10 exposures in all periods; 9.5% of address locations were within 50 m of a main road. Exposure estimates will be used in a number of planned epidemiological studies. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Exposure Knowledge and Perception of Wireless Communication Technologies.

PubMed

Freudenstein, Frederik; Correia, Luis M; Oliveira, Carla; Sebastião, Daniel; Wiedemann, Peter M

2015-11-06

The presented survey investigates risk and exposure perceptions of radio frequency electromagnetic fields (RF EMF) associated with base stations, mobile phones and other sources, the key issue being the interaction between both sets of perceptions. The study is based on a cross-sectional design, and conducted with an online sample of 838 citizens from Portugal. The results indicate that respondents' intuitive exposure perception differs from the actual exposure levels. Furthermore, exposure and risk perceptions are found to be highly correlated. Respondents' beliefs about exposure factors, which might influence possible health risks, is appropriate. A regression analysis between exposure characteristics, as predictor variables, and RF EMF risk perception, as the response variable, indicates that people seem to use simple heuristics to form their perceptions. What is bigger, more frequent and longer lasting is seen as riskier. Moreover, the quality of exposure knowledge is not an indicator for amplified EMF risk perception. These findings show that exposure perception is key to future risk communication.

Exposure Knowledge and Perception of Wireless Communication Technologies

PubMed Central

Freudenstein, Frederik; Correia, Luis M.; Oliveira, Carla; Sebastião, Daniel; Wiedemann, Peter M.

2015-01-01

The presented survey investigates risk and exposure perceptions of radio frequency electromagnetic fields (RF EMF) associated with base stations, mobile phones and other sources, the key issue being the interaction between both sets of perceptions. The study is based on a cross-sectional design, and conducted with an online sample of 838 citizens from Portugal. The results indicate that respondents’ intuitive exposure perception differs from the actual exposure levels. Furthermore, exposure and risk perceptions are found to be highly correlated. Respondents’ beliefs  about exposure factors, which might influence possible health risks, is appropriate. A regression analysis between exposure characteristics, as predictor variables, and RF EMF risk perception, as the response variable, indicates that people seem to use simple heuristics to form their perceptions. What is bigger, more frequent and longer lasting is seen as riskier. Moreover, the quality of exposure knowledge is not an indicator for amplified EMF risk perception. These findings show that exposure perception is key to future risk communication. PMID:26561826

Predictors of post-traumatic stress symptoms in Oklahoma City: exposure, social support, peri-traumatic responses.

PubMed

Tucker, P; Pfefferbaum, B; Nixon, S J; Dickson, W

2000-11-01

Eighty-five adults seeking mental health assistance six months after the Oklahoma City bombing were assessed to determine which of three groups of variables (exposure, peri-traumatic responses, and social support) predicted development of post-traumatic stress disorder (PTSD) symptoms. Variables most highly associated with subsequent PTSD symptoms included having been injured (among exposure variables), feeling nervous or afraid (peri-traumatic responses), and responding that counseling helped (support variables). Combining primary predictors in the three areas, PTSD symptoms were more likely to occur in those reporting counseling to help and those feeling nervous or afraid at the time of the bombing. Implications of these findings are discussed for behavioral health administrators and clinicians planning service delivery to groups of victims seeking mental health intervention after terrorist attacks and other disasters.

Characteristic and Source of Atmospheric PM10- and PM2.5-bound PAHs in a Typical Metallurgic City Near Yangtze River in China.

PubMed

Zhang, Hong; Wang, Ruwei; Xue, Huaqin; Hu, Ruoyu; Liu, Guijian

2018-02-01

The characteristics of atmospheric PM 10 - and PM 2.5 -bound polycyclic aromatic hydrocarbons (PAHs) were investigated in Tongling city, China. Results showed that the total concentrations of PM 10 - and PM 2.5 -bound PAHs exhibited distinct seasonal and spatial variability. The metallurgic sites showed the highest PAH concentrations, which is mainly attributed to the metallurgic activities (mainly copper ore smelting) and coal combustion as the smelting fuel. The rural area showed the lowest concentrations, but exhibited significant increase from summer to autumn. This seasonal fluctuation is mainly caused by the biomass burning at the sites in the harvest season. The diagnostic ratio indicated that the main PAHs sources were vehicle exhausts, coal combustion and biomass burning. The total BaP equivalent concentration (BAP-TEQ) was found to be maximum at DGS site in winter, whereas it was minimum at BGC site in summer. Risk assessment indicates that residential exposure to PAHs in the industrial area, especially in the winter season, may pose a greater inhalation cancer risk than people living in living area and rural area.

Aggregate-level lead exposure, gun violence, homicide, and rape

PubMed Central

Nelson, Erik J.; Qian, Zhengmin; Vaughn, Michael G.; Wright, John P.; Beaver, Kevin M.; Barnes, J. C.; Petkovsek, Melissa; Lewis, Roger; Schootman, Mario; Rosenfeld, Richard

2017-01-01

Context An increasing body of research has linked the geographic distribution of lead with various indicators of criminal and antisocial behavior. Objective The current study, using data from an ongoing project related to lead exposure in St. Louis City, MO, analyzed the association between aggregate blood lead levels and specific indicators violent crime within the city. Design Ecological study. Setting St. Louis, Missouri. Exposure measure Blood lead levels. Main outcome measure Official reports of violent crimes were categorized as 1) crimes involving a firearm (yes/no), 2) assault crimes (with or without a firearm), 3) robbery crimes (with or without a firearm), 4) homicides and 5) rape. Results With the exception of rape, aggregate blood-lead levels were statistically significant predictors of violent crime at the census tract level. The risk ratios for each of the outcome measures were as follows: firearm crimes 1.03 (1.03–1.04), assault crimes 1.03 (1.02–1.03), robbery crimes 1.03 (1.02–1.04), homicide 1.03 (1.01, 1.04), and rape 1.01 (0.99–1.03). Conclusions Extending prior research in St. Louis, results suggest that aggregated lead exposure at the census tract level predicted crime outcomes, even after accounting for important sociological variables. Moving forward, a more developed understanding of aggregate level crime may necessitate a shift toward studying the synergy between sociological and biological risk factors such as lead exposure. PMID:29176826

Social hierarchy modulates responses of fish exposed to contaminants of emerging concern.

PubMed

Ivanova, Jelena; Zhang, Shiju; Wang, Rong-Lin; Schoenfuss, Heiko L

2017-01-01

Many organisms, including the fathead minnow (Pimephales promelas), a toxicological model organism, establish social hierarchies. The social rank of each male in a population is under the control of the hypothalamic-pituitary-gonadal (HPG) axis mainly through regulation of circulating androgen concentrations, which in turn drive the expression of secondary sex characteristics (SSCs). As dominant and subordinate males in an exposure study are initially under different physiological conditions (i.e., differing plasma androgen concentrations), we proposed that they belong to different subpopulations in the context of exposure to compounds that may interact with the HPG axis. Using a meta-analysis of our data from several previously published studies, we corroborated the hypothesis that social status, as indicated by SSCs, results in distinct clusters (eigenvalues >0.8 explaining >80% of variability) with differential expression of plasma vitellogenin, a commonly used biomarker of exposure to contaminants of emerging concern (CEC). Furthermore, we confirmed our predictions that exposure to estrogenic CECs would homogenize plasma vitellogenin response (E1: cluster mean SSC values decreased to 4.33 and 4.86 relative to those of control; E2: decreased to 4.8 and 5.37) across the social hierarchy. In contrast, serotonin-specific reuptake inhibitors expand this response range (cluster mean SSC increased to 5.21 and 6.5 relative to those of control). Our results demonstrated that social hierarchies in male fathead minnows result in heterogeneous responses to chemical exposure. These results represent a cautionary note for the experimental design of single-sex exposure studies. We anticipate our study to be a starting point for the re-evaluation of toxicological data analyses in single sex exposure experiments.

OUTDOOR VS. HUMAN EXPOSURE: NERL PM EXPOSURE PANEL STUDIES

EPA Science Inventory

An association has been demonstrated between ambient particulate matter (PM 2.5 and PM 10) concentrations and human morbidity/mortality. However, little is known regarding the most important sources of PM exposure, interpersonal and intrapersonal variability in exposure, and the...

Habitat traits and patterns of abundance of the purple sea urchin, Paracentrotus lividus (Lamarck, 1816), at multiple scales along the north Portuguese coast

NASA Astrophysics Data System (ADS)

Domínguez, Rula; Domínguez Godino, Jorge; Freitas, Cristiano; Machado, Inês; Bertocci, Iacopo

2015-03-01

Spatial and temporal patterns of abundance and distribution of sea urchins (Paracentrotus lividus) from intertidal rockpools of the north Portuguese coast were examined in relation to physical (surface, altitude, depth, topographic complexity and exposure) and biological (substrate cover by dominant organisms) habitat traits. The methodology was based on a multi-factorial design where the total number and the abundance of urchins in each of six size classes were sampled over a range of spatial scales, from 10s of cm to kms, and a temporal scale of five months. The results highlighted three main features of the studied system: (1) the largest proportion of variability of sea urchins occurred at the smallest scale examined; (2) urchins from different size classes showed different patterns of abundance in relation to habitat traits; (3) variables normally invoked as potential drivers of distribution of urchins at a range of scales, such as hydrodynamics and shore height, were relatively less important than other abiotic (i.e. pool area, pool mean depth calculated over five replicate measures and sand cover) and biological (i.e. space occupancy by the reef-forming polychaete Sabellaria alveolata and mussels vs. availability of bare rock) variables to provide a considerable contribution to the variability of sea urchins. Intertidal populations of sea urchins are abundant on many rocky shores, where they are socially and economically important as food resource and ecologically key as habitat modelers. This study provides new clues on relatively unstudied populations, with relevant implications for possible management decisions, including the implementation of protection schemes able to preserve the main recruitment, settlement and development areas of P. lividus.

Low within- and between-day variability in exposure to new insulin glargine 300 U/ml.

PubMed

Becker, R H A; Nowotny, I; Teichert, L; Bergmann, K; Kapitza, C

2015-03-01

To characterize the variability in exposure and metabolic effect of insulin glargine 300 U/ml (Gla-300) at steady state in people with type 1 diabetes (T1DM). A total of 50 participants with T1DM underwent two 24-h euglycaemic clamps in steady-state conditions after six once-daily administrations of 0.4 U/kg Gla-300 in a double-blind, randomized, two-treatment, two-period, crossover clamp study. Participants were randomized to receive Gla-300 as a standard cartridge formulation in the first treatment period, and as a formulation with enhanced stability through polysorbate-20 addition in the second treatment period, or vice versa. This design allowed the assessment of bioequivalence between formulations and, subsequently, within- and between-day variability. The cumulative exposure and effect of Gla-300 developed linearly over 24 h, and were evenly distributed across 6- and 12-h intervals. Diurnal fluctuation in exposure (within-day variability) was low; the peak-to-trough ratio of insulin concentration profiles was <2, and both the swing and peak-to-trough fluctuation were <1. Day-to-day reproducibility of exposure was high: the between-day within-subject coefficients of variation for total systemic exposure (area under the serum insulin glargine concentration time curve from time 0 to 24 h after dosing) and maximum insulin concentration were 17.4% [95% confidence interval (CI) 15-21] and 33.4% (95% CI 28-41), respectively. Reproducibility of the metabolic effect was lower than that of exposure. Gla-300 provides predictable, evenly distributed 24-h coverage as a result of low fluctuation and high reproducibility in insulin exposure, and appears suitable for effective basal insulin use. © 2014 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.

Effect of cumulative exposure to corticosteroid and DMARD on radiographic progression in rheumatoid arthritis: results from the ESPOIR cohort.

PubMed

Louveau, Baptiste; De Rycke, Yann; Lafourcade, Alexandre; Saraux, Alain; Guillemin, Francis; Tubach, Florence; Fautrel, Bruno; Hajage, David

2018-05-22

Several authors have tried to predict the risk of radiographic progression in RA according to baseline characteristics, considering exposure to treatment only as a binary variable (Treated: Yes/No). This study aims to model the risk of 5-year radiographic progression taking into account both baseline characteristics and the cumulative time-varying exposure to corticosteroids or DMARDs. The study population consisted of 403 patients of the Etude et Suivi des Polyarthrites Indifférenciées Récentes cohort meeting the 1987 ACR or 2010 ACR/EULAR criteria for RA at inclusion and having complete radiographic data at baseline and 5 years. Radiographic progression was defined at 5 years as a significant increase of the Sharp/van der Heidje score (smallest detectable difference ⩾5). The best logistic regression model was selected from the following: model including only clinico-biological baseline characteristics; model considering baseline characteristics and treatments as binary variables; and model considering baseline characteristics and treatments as weighted cumulative exposure variables. Radiographic progression occurred in 143 (35.5%) patients. The best model combined anti-citrullinated peptide antibody positivity, ESR, swollen joint count >14 and erosion score at baseline, as well as corticosteroids, MTX/LEF (MTX or LEF) and biologic DMARDs (bDMARDs) as weighted cumulative exposure variables. Recent cumulative exposure to high doses of corticosteroids (⩽ 3months) was significantly associated with the risk of 5-year radiographic progression and a significant protective association was highlighted for a 36-month exposure to bDMARDs. Corticosteroids and bDMARDs play an important role in radiographic progression. Accounting for treatment class and intensity of exposure is a major concern in predictive models of radiographic progression in RA patients.

Reproductive and developmental effects of disinfection by-products in drinking water.

PubMed Central

Reif, J S; Hatch, M C; Bracken, M; Holmes, L B; Schwetz, B A; Singer, P C

1996-01-01

Recent epidemiologic studies have reported associations between the consumption of chlorinated drinking water and reproductive and developmental effects. Here we review the available epidemiologic data, assess the hazard potential posed by exposure to disinfection by-products, identify critical data gaps, and offer recommendations for further research. The epidemiologic evidence supporting associations between exposure to water disinfection by-products (DBPs) and adverse pregnancy outcomes is sparse, and positive findings should be interpreted cautiously. The methods used during the early stages of research in this area have been diverse. Variability in exposure assessment and endpoints makes it difficult to synthesize or combine the available data. Exposure misclassification and unmeasured confounding may have lead to bias in risk estimation. Future studies of reproductive outcome and exposure to chlorinated water should use improved methods for exposure assessment to 1) assure selection of appropriate exposure markers, 2) assess seasonal and annual fluctuations in DBPs, 3) assess variability within the distribution system, and 4) assess exposure through multiple routes such as bathing and showering, as well as consumption. Population-based studies should be conducted to evaluate male and female fertility, conception delay, growth retardation, and specific birth defects. The reproductive and developmental effects of exposure to DBPs could be efficiently explored in ongoing investigations by incorporating valid exposure markers and relevant questionnaire information. Future studies should make use of naturally occurring variability in the concentrations of DBPs and may incorporate biomarkers of exposure and effect in their design. Epidemiologic investigations should be conducted in parallel with laboratory-based and animal studies in a coordinated, multidisciplinary approach. PMID:8930546

Health and household air pollution from solid fuel use: the need for improved exposure assessment.

PubMed

Clark, Maggie L; Peel, Jennifer L; Balakrishnan, Kalpana; Breysse, Patrick N; Chillrud, Steven N; Naeher, Luke P; Rodes, Charles E; Vette, Alan F; Balbus, John M

2013-10-01

Nearly 3 billion people worldwide rely on solid fuel combustion to meet basic household energy needs. The resulting exposure to air pollution causes an estimated 4.5% of the global burden of disease. Large variability and a lack of resources for research and development have resulted in highly uncertain exposure estimates. We sought to identify research priorities for exposure assessment that will more accurately and precisely define exposure-response relationships of household air pollution necessary to inform future cleaner-burning cookstove dissemination programs. As part of an international workshop in May 2011, an expert group characterized the state of the science and developed recommendations for exposure assessment of household air pollution. The following priority research areas were identified to explain variability and reduce uncertainty of household air pollution exposure measurements: improved characterization of spatial and temporal variability for studies examining both short- and long-term health effects; development and validation of measurement technology and approaches to conduct complex exposure assessments in resource-limited settings with a large range of pollutant concentrations; and development and validation of biomarkers for estimating dose. Addressing these priority research areas, which will inherently require an increased allocation of resources for cookstove research, will lead to better characterization of exposure-response relationships. Although the type and extent of exposure assessment will necessarily depend on the goal and design of the cookstove study, without improved understanding of exposure-response relationships, the level of air pollution reduction necessary to meet the health targets of cookstove interventions will remain uncertain.

Chapter One: Exposure Measurements.

EPA Science Inventory

Determining human exposure to suspended particualte concentrations requires measurements that quantify different particle properties in microenvironments where people live, work, and play. Particle mass, size, and chemical composition are important exposure variables, and these ...

CHAPTER ONE: EXPOSURE MEASUREMENTS.

EPA Science Inventory

Determining human exposure to suspended particualte concentrations requires measurements that quantify different particle properties in microenvironments where people live, work, and play. Particle mass, size, and chemical composition are important exposure variables, and these ...

Timing matters: change depends on the stage of treatment in cognitive behavioral therapy for panic disorder with agoraphobia.

PubMed

Gloster, Andrew T; Klotsche, Jens; Gerlach, Alexander L; Hamm, Alfons; Ströhle, Andreas; Gauggel, Siegfried; Kircher, Tilo; Alpers, Georg W; Deckert, Jürgen; Wittchen, Hans-Ulrich

2014-02-01

The mechanisms of action underlying treatment are inadequately understood. This study examined 5 variables implicated in the treatment of panic disorder with agoraphobia (PD/AG): catastrophic agoraphobic cognitions, anxiety about bodily sensations, agoraphobic avoidance, anxiety sensitivity, and psychological flexibility. The relative importance of these process variables was examined across treatment phases: (a) psychoeducation/interoceptive exposure, (b) in situ exposure, and (c) generalization/follow-up. Data came from a randomized controlled trial of cognitive behavioral therapy for PD/AG (n = 301). Outcomes were the Panic and Agoraphobia Scale (Bandelow, 1995) and functioning as measured in the Clinical Global Impression scale (Guy, 1976). The effect of process variables on subsequent change in outcome variables was calculated using bivariate latent difference score modeling. Change in panic symptomatology was preceded by catastrophic appraisal and agoraphobic avoidance across all phases of treatment, by anxiety sensitivity during generalization/follow-up, and by psychological flexibility during exposure in situ. Change in functioning was preceded by agoraphobic avoidance and psychological flexibility across all phases of treatment, by fear of bodily symptoms during generalization/follow-up, and by anxiety sensitivity during exposure. The effects of process variables on outcomes differ across treatment phases and outcomes (i.e., symptomatology vs. functioning). Agoraphobic avoidance and psychological flexibility should be investigated and therapeutically targeted in addition to cognitive variables. PsycINFO Database Record (c) 2014 APA, all rights reserved.

A system's approach to assess the exposure of agricultural production to climate change and variability

USDA-ARS?s Scientific Manuscript database

Estimating the exposure of agriculture to climate variability and change can help us to understand the key vulnerability as well as improve the adaptive capacity which is important for increasing food production to feed the world’s increasing population. A number of indices are available in literat...

Prenatal exposure to lead in Spain: cord blood levels and associated factors.

PubMed

Llop, Sabrina; Aguinagalde, Xabier; Vioque, Jesus; Ibarluzea, Jesús; Guxens, Mònica; Casas, Maribel; Murcia, Mario; Ruiz, María; Amurrio, Ascensión; Rebagliato, Marisa; Marina, Loreto Santa; Fernandez-Somoano, Ana; Tardon, Adonina; Ballester, Ferran

2011-05-01

Lead is a known neurotoxic. Fetuses and infants are very vulnerable to lead exposure, since their blood-brain barrier is not completely formed. Hence, there is an importance for monitoring of blood lead levels prenatally and during early infancy. The aim of this study is to evaluate the prenatal exposure to lead and its association with maternal factors in four population based mother-child cohorts in Spain. The present research was carried out within the framework of the INMA project INfancia y Medio Ambiente (Environment and Childhood). A total of 1462 pregnant women were recruited between 2004 and 2008. Lead was analyzed in a sample of cord blood by thermal decomposition, amalgation, and Atomic Absorption Spectrometry. Maternal sociodemographic, lifestyle and dietary factors were obtained by questionnaires during pregnancy. A multivariate logistic regression model was constructed. The dependent variable was a dichotomous lead level variable (detected vs no detected, i.e. ≥ vs < 2μg/dL). A low percentage of cord blood samples with lead levels ≥ 2μg/dL were found (5.9%). Geometric mean and maximum were 1.06μg/dL and 19μg/dL, respectively. Smoking at the beginning of pregnancy, age, social class, weight gain during pregnancy, gravidity, and place of residence were the maternal factors associated with detectable cord blood lead levels. Mother's diet does not appear to be a determining factor of lead exposure. Nevertheless, daily intake of iron and zinc may act as a protective factor against having cord blood lead levels ≥ 2μg/dL. In the different regions of Spain taking part in this study, lead levels to which newborns are exposed are low. Mobilization of lead from bones may be the main contributor to the cord blood levels. Copyright © 2011 Elsevier B.V. All rights reserved.

Variability of pesticide exposure in a stream mesocosm system: macrophyte-dominated vs. non-vegetated sections.

PubMed

Beketov, Mikhail A; Liess, Matthias

2008-12-01

For flowing water bodies no information is available about patterns of contaminant distribution in flowing water compared to macrophyte-dominated structures. The aim of the study was to examine temporal dynamic and spatial cross-channel variability of pulse exposure of the insecticide thiacloprid in outdoor stream mesocosms. Two distinct cross-channel sections have been considered: macrophyte-dominated littoral and non-vegetated midstream. Median disappearance time ranged from 17 to 43 h (water phase, midstream). We showed that during the exposure pulse (10h) thiacloprid concentrations in the macrophyte-dominated section were 20-60% lower than those in the non-vegetated section. This suggests that spatial variability in contaminant concentrations, particularly in streams containing macrophytes, should be taken into account to enable a more realistic assessment of (i) exposure and associated effects and (ii) mass transport of pesticides and other chemicals into river systems (e.g. losses with surface runoff).

The effect of spatial distribution on the annoyance caused by simultaneous sounds

NASA Astrophysics Data System (ADS)

Vos, Joos; Bronkhorst, Adelbert W.; Fedtke, Thomas

2004-05-01

A considerable part of the population is exposed to simultaneous and/or successive environmental sounds from different sources. In many cases, these sources are different with respect to their locations also. In a laboratory study, it was investigated whether the annoyance caused by the multiple sounds is affected by the spatial distribution of the sources. There were four independent variables: (1) sound category (stationary or moving), (2) sound type (stationary: lawn-mower, leaf-blower, and chain saw; moving: road traffic, railway, and motorbike), (3) spatial location (left, right, and combinations), and (4) A-weighted sound exposure level (ASEL of single sources equal to 50, 60, or 70 dB). In addition to the individual sounds in isolation, various combinations of two or three different sources within each sound category and sound level were presented for rating. The annoyance was mainly determined by sound level and sound source type. In most cases there were neither significant main effects of spatial distribution nor significant interaction effects between spatial distribution and the other variables. It was concluded that for rating the spatially distrib- uted sounds investigated, the noise dose can simply be determined by a summation of the levels for the left and right channels. [Work supported by CEU.

Organic solvent exposure and depressive symptoms among licensed pesticide applicators in the Agricultural Health Study

PubMed Central

Siegel, Miriam; Starks, Sarah E.; Sanderson, Wayne T.; Kamel, Freya; Hoppin, Jane A.; Gerr, Fred

2017-01-01

Purpose Although organic solvents are often used in agricultural operations, neurotoxic effects of solvent exposure have not been extensively studied among famers. The current analysis examined associations between questionnaire-based metrics of organic solvent exposure and depressive symptoms among farmers. Methods Results from 692 male Agricultural Health Study participants were analyzed. Solvent type and exposure duration were assessed by questionnaire. An “ever-use” variable and years of use categories were constructed for exposure to gasoline, paint/lacquer thinner, petroleum distillates, and any solvent. Depressive symptoms were ascertained with the Center for Epidemiologic Studies Depression Scale (CES-D); scores were analyzed separately as continuous (0-60) and dichotomous (<16 versus ≥16) variables. Multivariate linear and logistic regression models were used to estimate crude and adjusted associations between measures of solvent exposure and CES-D score. Results Forty-one percent of the sample reported some solvent exposure. The mean CES-D score was 6.5 (SD=6.4; median=5; range=0 – 44); 92% of the sample had a score below 16. After adjusting for covariates, statistically significant associations were observed between ever-use of any solvent, long duration of any solvent exposure, ever-use of gasoline, ever-use of petroleum distillates, and short duration of petroleum distillate exposure and continuous CES-D score (p<0.05). Although nearly all associations were positive, fewer statistically significant associations were observed between metrics of solvent exposure and the dichotomized CES-D variable. Conclusions Solvent exposures were associated with depressive symptoms among farmers. Efforts to limit exposure to organic solvents may reduce the risk of depressive symptoms among farmers. PMID:28702848

MODELING OF HUMAN EXPOSURE TO IN-VEHICLE PM2.5 FROM ENVIRONMENTAL TOBACCO SMOKE

PubMed Central

Cao, Ye; Frey, H. Christopher

2012-01-01

Environmental tobacco smoke (ETS) is estimated to be a significant contributor to in-vehicle human exposure to fine particulate matter of 2.5 µm or smaller (PM2.5). A critical assessment was conducted of a mass balance model for estimating PM2.5 concentration with smoking in a motor vehicle. Recommendations for the range of inputs to the mass-balance model are given based on literature review. Sensitivity analysis was used to determine which inputs should be prioritized for data collection. Air exchange rate (ACH) and the deposition rate have wider relative ranges of variation than other inputs, representing inter-individual variability in operations, and inter-vehicle variability in performance, respectively. Cigarette smoking and emission rates, and vehicle interior volume, are also key inputs. The in-vehicle ETS mass balance model was incorporated into the Stochastic Human Exposure and Dose Simulation for Particulate Matter (SHEDS-PM) model to quantify the potential magnitude and variability of in-vehicle exposures to ETS. The in-vehicle exposure also takes into account near-road incremental PM2.5 concentration from on-road emissions. Results of probabilistic study indicate that ETS is a key contributor to the in-vehicle average and high-end exposure. Factors that mitigate in-vehicle ambient PM2.5 exposure lead to higher in-vehicle ETS exposure, and vice versa. PMID:23060732

The effect of the presence and characteristics of an outlying group on exposure-outcome associations.

PubMed

Coenen, Pieter; Mathiassen, Svend Erik; Kingma, Idsart; Boot, Cécile R L; Bongers, Paulien M; van Dieën, Jaap H

2015-01-01

Physical exposures (eg, lifting or bending) are believed to be risk factors for low-back pain (LBP), but the literature is inconsistent. Exposure and LBP prevalence differ considerably between occupations, and exposure-outcome associations could be severely modified by the presence of particular occupational groups. We aimed to investigate the influence of such outlying groups on the properties of associations between exposure and LBP. Lifting and trunk flexion were observed for 371 of 1131 workers within 19 groups. LBP was obtained from all workers during three follow-up years. Both exposure variables were associated with LBP (P<0.01) in this parent dataset. By removing the 19 groups one-by-one and performing logistic regressions analysis on the 18 remaining groups, we demonstrated that one group, mainly road workers, with outlying exposures and LBP prevalence substantially affected the exposure-outcome association in the total population. In order to further examine this phenomenon, we assessed, by simulation, the influence of realistic sizes (n=4, 8, 16, 32, 64, 128), mean exposures (e=2000, 3000, 4000 lifts and e=30, 40, 50% trunk flexion time) and LBP prevalences (p=70, 80, 90, 100%) of the outlying group on the strength and certainty of the eventual relationship between exposure and LBP. For each combination of n, e and p, 3000 virtual studies were constructed, including the simulated group together with the other 18 original groups from the parent data-set. Average odds ratios (OR), 95% confidence limits, and power (P<0.05) were calculated across these 3000 studies as measures of the properties of each virtual study design. OR were attenuated more towards 1 and power decreased with smaller values of n, e, and p in the outlying group. Changes in group size and prevalence had a larger influence on OR and power than changes in mean exposure. The size and characteristics of a single group with high exposure and outcome prevalence can strongly influence both the OR point estimate and the likelihood of obtaining significant exposure-outcome associations in studies of large populations. These findings can guide interpretations of prior epidemiological studies and support informed design of future studies.

Post-exposure prophylaxis against rabies at two newly designated intradermal rabies vaccination clinics in Kerala, India.

PubMed

J, Teena M; Mathew, T; S, Anish T; M, Sujina C; Philip, R R

2012-01-01

The two-site intradermal rabies vaccination (IDRV) regimen was recently introduced in Kerala. We aimed to determine factors associated with exposure of category III severity among patients seeking prophylaxis against rabies at IDRV clinics. This hospital-based, cross-sectional study was done at two clinics in Thiruvananthapuram district, Kerala. Data were collected using a semi-structured questionnaire by direct interview and 320 patients were included. Bivariate analysis of quantitative variables was done using t-test and that of qualitative variables using chi-square test. The mean (standard deviation) age of patients was 32.4 (19.6) years. Among the 320 cases, 202 (63.1%) had category III exposure. Lower extremities were the most frequent site of exposure (146, 45.6%). The most frequent mode of exposure was being bitten by an animal (214, 66.9%), often a dog. Residence in rural areas, exposure to dogs and wounds on the extremities had a significant association with severity of exposure. Animal exposures were more among people from rural areas. About two-thirds of exposures which necessitated post-exposure prophylaxis were category III. Copyright 2012, NMJI.

[Assessment of risk of death due to malignant neoplasms induced by occupational exposure in a rubber footwear plant].

PubMed

Szymczak, Wiesław; Sobala, Wojciech; Wilczyńska, Urszula; Szeszenia-Dabrowska, Neonila

2003-01-01

The main goal of the study was to analyze thoroughly the results of a cohort study. Such an analysis renders it possible to eliminate certain neoplasms as those not related to the observed exposure. The cohort study was carried out in a group of workers, covering 11,342 persons (5472 men and 5870 women), employed for at least one year during the years 1945-1985 in a rubber footwear plant. The cohort study was continued until the end of December 1997. Of all the sites of malignant neoplasms observed in the cohort, significant, exposure-related excess mortality was found to be due to malignant neoplasms of larynx and lung in men, and malignant neoplasms of gallbladder and lung in women. For these neoplasms, the values of observed risk among those exposed were significantly higher than among non-exposed. Moreover, in a certain interval of employment duration, an increase in risk rates with increasing duration of employment under exposure was observed, which suggests the presence of dose-response relationship. For all these sites, a relevant trend was shown by the RR values calculated in relation to the group of persons non-exposed but employed in the same plant. The internal reference group used to calculate RR values allowed to eliminate the effect of confounding variables, which is not always possible when the general population is used as the reference group.

Sequential Measurement of Intermodal Variability in Public Transportation PM2.5 and CO Exposure Concentrations.

PubMed

Che, W W; Frey, H Christopher; Lau, Alexis K H

2016-08-16

A sequential measurement method is demonstrated for quantifying the variability in exposure concentration during public transportation. This method was applied in Hong Kong by measuring PM2.5 and CO concentrations along a route connecting 13 transportation-related microenvironments within 3-4 h. The study design takes into account ventilation, proximity to local sources, area-wide air quality, and meteorological conditions. Portable instruments were compacted into a backpack to facilitate measurement under crowded transportation conditions and to quantify personal exposure by sampling at nose level. The route included stops next to three roadside monitors to enable comparison of fixed site and exposure concentrations. PM2.5 exposure concentrations were correlated with the roadside monitors, despite differences in averaging time, detection method, and sampling location. Although highly correlated in temporal trend, PM2.5 concentrations varied significantly among microenvironments, with mean concentration ratios versus roadside monitor ranging from 0.5 for MTR train to 1.3 for bus terminal. Measured inter-run variability provides insight regarding the sample size needed to discriminate between microenvironments with increased statistical significance. The study results illustrate the utility of sequential measurement of microenvironments and policy-relevant insights for exposure mitigation and management.

Trends in OSHA Compliance Monitoring Data 1979-2011: Statistical Modeling of Ancillary Information across 77 Chemicals.

PubMed

Sarazin, Philippe; Burstyn, Igor; Kincl, Laurel; Lavoué, Jérôme

2016-05-01

The Integrated Management Information System (IMIS) is the largest multi-industry source of exposure measurements available in North America. However, many have suspected that the criteria through which worksites are selected for inspection are related to exposure levels. We investigated associations between exposure levels and ancillary variables in IMIS in order to understand the predictors of high exposure within an enforcement context. We analyzed the association between nine variables (reason for inspection, establishment size, total amount of penalty, Occupational Safety and Health Administration (OSHA) plan, OSHA region, union status, inspection scope, year, and industry) and exposure levels in IMIS using multimodel inference for 77 agents. For each agent, we used two different types of models: (i) logistic models were used for the odds ratio (OR) of exposure being above the threshold limit value (TLV) and (ii) linear models were used for exposure concentrations restricted to detected results to estimate percent increase in exposure level, i.e. relative index of exposure (RIE). Meta-analytic methods were used to combine results for each variable across agents. A total of 511,047 exposure measurements were modeled for logistic models and 299,791 for linear models. Higher exposures were measured during follow-up inspections than planned inspections [meta-OR = 1.61, 95% confidence interval (CI): 1.44-1.81; meta-RIE = 1.06, 95% CI: 1.03-1.09]. Lower exposures were observed for measurements collected under state OSHA plans compared to measurements collected under federal OSHA (meta-OR = 0.82, 95% CI: 0.73-0.92; meta-RIE = 0.86, 95% CI: 0.81-0.91). A 'high' total historical amount of penalty relative to none was associated with higher exposures (meta-OR = 1.54, 95% CI: 1.40-1.71; meta-RIE = 1.18, 95% CI: 1.13-1.23). The relationships observed between exposure levels and ancillary variables across a vast majority of agents suggest that certain elements of OSHA's process of selecting worksites for inspection influence the exposure levels that OSHA inspectors encounter. Nonetheless, given the paucity of other sources of exposure data and the lack of a more demonstrably representative data source, our study considers the use of IMIS data for the estimation of exposures in the broader universe of worksites in the USA. © The Author 2016. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Beyond symptom self-report: use of a computer "avatar" to assess post-traumatic stress disorder (PTSD) symptoms.

PubMed

Myers, Catherine E; Radell, Milen L; Shind, Christine; Ebanks-Williams, Yasheca; Beck, Kevin D; Gilbertson, Mark W

2016-11-01

Post-traumatic stress disorder (PTSD) can occur in the wake of exposure to a traumatic event. Currently, PTSD symptoms are assessed mainly through self-report in the form of questionnaire or clinical interview. Self-report has inherent limitations, particularly in psychiatric populations who may have limited awareness of deficit, reduced attention span, or poor vocabulary and/or literacy skills. Diagnosis and evaluation of treatment efficacy would be aided by behavioral measures. A viable alternative may be virtual environments, in which the participant guides an on-screen "avatar" through a series of onscreen events meant to simulate real-world situations. Here, a sample of 82 veterans, self-assessed for PTSD symptoms was administered such a task, in which the avatar was confronted with situations that might evoke avoidant behavior, a core feature of PTSD. Results showed a strong correlation between PTSD symptom burden and task performance; in fact, the ability to predict PTSD symptom burden based on simple demographic variables (age, sex, combat exposure) was significantly improved by adding task score as a predictor variable. The results therefore suggest that virtual environments may provide a new way to assess PTSD symptoms, while avoiding at least some of the limitations associated with symptom self-report, and thus might be a useful complement to questionnaire or clinical interview, potentially facilitating both diagnosis and evaluation of treatment efficacy.

Prevalence of smoke-free car and home rules in Maine before and after passage of a smoke-free vehicle law, 2007-2010.

PubMed

Murphy-Hoefer, Rebecca; Madden, Patrick; Maines, Dorean; Coles, Carol

2014-01-16

This is the first study to examine the prevalence of self-reported smoke-free rules for private cars and homes before and after the passage of a smoke-free vehicle law. Data were examined for 13,461 Maine adults aged 18 or older who participated in the Behavioral Risk Factor Surveillance System, a state-based telephone survey covering health topics. Self-reported smoke-free car and home rules, smoking behavior, and demographic variables of age, sex, education, income, and children in household were analyzed for prevalence before and after the state's smoke-free vehicle law was passed. Prevalence of smoke-free car and home rules was significantly higher after Maine's smoke-free vehicle law was passed in the state (P = .004 for car rules and P = .009 for home rules). Variations in smoking rules differed by smoking and demographic variables. People with household incomes of less than $20,000 saw an increase of 14.3% in smoke-free car rules; overall, those with annual incomes of less than $20,000 and those with less than a high school education reported a lower prevalence of smoke-free car rules both before and after the law was passed than did people with higher incomes and higher education levels. The prevalence of smoke-free home rules after the law was implemented was higher among those with 4 or more years of college education than among those with lower levels of education (P = .02). The prevalence of smoke-free car and home rules among Maine adults was significantly higher after the passage of a statewide smoke-free vehicle law. This apparent change in smoke-free rule prevalence may be indicative of changing social norms related to the unacceptability of secondhand smoke exposure.

Systematic correlation of environmental exposure and physiological and self-reported behaviour factors with leukocyte telomere length.

PubMed

Patel, Chirag J; Manrai, Arjun K; Corona, Erik; Kohane, Isaac S

2017-02-01

It is hypothesized that environmental exposures and behaviour influence telomere length, an indicator of cellular ageing. We systematically associated 461 indicators of environmental exposures, physiology and self-reported behaviour with telomere length in data from the US National Health and Nutrition Examination Survey (NHANES) in 1999-2002. Further, we tested whether factors identified in the NHANES participants are also correlated with gene expression of telomere length modifying genes. We correlated 461 environmental exposures, behaviours and clinical variables with telomere length, using survey-weighted linear regression, adjusting for sex, age, age squared, race/ethnicity, poverty level, education and born outside the USA, and estimated the false discovery rate to adjust for multiple hypotheses. We conducted a secondary analysis to investigate the correlation between identified environmental variables and gene expression levels of telomere-associated genes in publicly available gene expression samples. After correlating 461 variables with telomere length, we found 22 variables significantly associated with telomere length after adjustment for multiple hypotheses. Of these varaibales, 14 were associated with longer telomeres, including biomarkers of polychlorinated biphenyls([PCBs; 0.1 to 0.2 standard deviation (SD) increase for 1 SD increase in PCB level, P  < 0.002] and a form of vitamin A, retinyl stearate. Eight variables associated with shorter telomeres, including biomarkers of cadmium, C-reactive protein and lack of physical activity. We could not conclude that PCBs are correlated with gene expression of telomere-associated genes. Both environmental exposures and chronic disease-related risk factors may play a role in telomere length. Our secondary analysis found no evidence of association between PCBs/smoking and gene expression of telomere-associated genes. All correlations between exposures, behaviours and clinical factors and changes in telomere length will require further investigation regarding biological influence of exposure. © The Author 2016. Published by Oxford University Press on behalf of the International Epidemiological Association

Airborne pollutant concentrations and health risks in selected Apulia region (IT) areas: preliminary results from the Jonico-Salentino project

NASA Astrophysics Data System (ADS)

Buccolieri, Riccardo; Genga, Alessandra; De Donno, Antonella; Siciliano, Tiziana; Siciliano, Maria; Serio, Francesca; Grassi, Tiziana; Rispoli, Gennaro; Cavaiola, Mattia; Lionello, Piero

2017-04-01

The Jonico-Salentino project (PJS) is a multidisciplinary study funded by Apulia Region (Det. N. 188_RU - 10/11/2015) aiming to assess health risk of people living in the cities of Lecce, Brindisi and Taranto. Citizens are exposed to emissions from industrial sources, biomass burning, vehicular, naval and air traffic, as well as from natural radioactive sources (radon). In this context, this work presents some preliminary results obtained by the Unit of University of Salento (Lecce) during an experimental campaign carried out in the study areas. The campaign is devoted to (i) sample particulate matter (PM), (ii) measure micro-meteorological variables and (iii) evaluate exposure levels of residents to main pollutants. Specifically, PM is sampled using a low volume sampler, while meteorological variables (wind speed components and direction temperature, relative humidity, precipitation and global solar radiation) are measured by advanced instrumentation such as ultrasonic anemometers which allows for the estimation of turbulence fluxes. The early effects of exposure to air pollutants is evaluated by the frequency of micronucleus (a biomarker of DNA damage) in exfoliated buccal cells collected using a soft-bristled toothbrush from oral mucosa of primary school children enrolled in the study. PM concentration data collected during the campaign are characterised from a chemical and morphological point of view; the analysis of different groups of particles allows identifying different natural and anthropogenic emission sources. This is done in conjunction to the investigation of the influence of local meteorology to elucidate the contribution of specific types of sources on final concentration levels. Finally, all data are used to assess the health risk of people living in the study areas as consequence of exposure to airborne pollutants.

Noise and sleep on board vessels in the Royal Norwegian Navy

PubMed Central

Sunde, Erlend; Bråtveit, Magne; Pallesen, Ståle; Moen, Bente Elisabeth

2016-01-01

Previous research indicates that exposure to noise during sleep can cause sleep disturbance. Seamen on board vessels are frequently exposed to noise also during sleep periods, and studies have reported sleep disturbance in this occupational group. However, studies of noise and sleep in maritime settings are few. This study's aim was to examine the associations between noise exposure during sleep, and sleep variables derived from actigraphy among seamen on board vessels in the Royal Norwegian Navy (RNoN). Data were collected on board 21 RNoN vessels, where navy seamen participated by wearing an actiwatch (actigraph), and by completing a questionnaire comprising information on gender, age, coffee drinking, nicotine use, use of medication, and workload. Noise dose meters were used to assess noise exposure inside the seamen's cabin during sleep. Eighty-three sleep periods from 68 seamen were included in the statistical analysis. Linear mixed-effects models were used to examine the association between noise exposure and the sleep variables percentage mobility during sleep and sleep efficiency, respectively. Noise exposure variables, coffee drinking status, nicotine use status, and sleeping hours explained 24.9% of the total variance in percentage mobility during sleep, and noise exposure variables explained 12.0% of the total variance in sleep efficiency. Equivalent noise level and number of noise events per hour were both associated with increased percentage mobility during sleep, and the number of noise events was associated with decreased sleep efficiency. PMID:26960785

Living in a continuous traumatic reality: Impact on elderly persons residing in urban and rural communities.

PubMed

Regev, Irit; Nuttman-Shwartz, Orit

2016-01-01

This study is an exploration of the contribution of exposure to the continuous threat of Qassam rocket attacks to PTSD among elderly residents of urban and rural communities. Specifically, we examined the contribution of sociodemographic variables, psychological resources, and perceived social support to PTSD, and whether this relationship is mediated by cognitive appraisals. The sample consisted of 298 residents of 2 different communities: urban (n = 190), and rural (n = 108). We examined the main research question by calculating the correlations of the sociodemographic variables, the psychological resource (self-esteem), social support, and cognitive appraisals with the dependent variable (PTSD). Our model explained the variance in PTSD (53% for urban residents, and 56% for rural residents). Higher levels of PTSD were found among the urban residents. Most of the predictors contributed to PTSD, but differences were found between each type of community with regard to the combination of components. Results indicated that the type of community is related degree of protection against stress-related triggers such as Qassam rockets. The psychological resource (self-esteem) and cognitive appraisal variables were found to be important for older people facing a continuous threat, and can serve as a basis for professional intervention. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

The Effect of Intensified Language Exposure on Accommodating Talker Variability

ERIC Educational Resources Information Center

Antoniou, Mark; Wong, Patrick C. M.; Wang, Suiping

2015-01-01

Purpose: This study systematically examined the role of intensified exposure to a second language on accommodating talker variability. Method: English native listeners (n = 37) were compared with Mandarin listeners who had either lived in the United States for an extended period of time (n = 33) or had lived only in China (n = 44). Listeners…

HUMAN EXPOSURE MODELING: CONCEPTS, METHODS, AND TOOLS

EPA Science Inventory

Understanding human exposure is critical when estimating the occurrence of deleterious effects that could follow contact with environmental contaminants. For many pollutants, the intensity, duration, frequency, route, and timing of exposure is highly variable, particularly whe...

Uncertainty and Variability

EPA Pesticide Factsheets

EPA ExpoBox is a toolbox for exposure assessors. Its purpose is to provide a compendium of exposure assessment and risk characterization tools that will present comprehensive step-by-step guidance and links to relevant exposure assessment data bases

Assessment and predictor determination of indoor aldehyde levels in Paris newborn babies' homes.

PubMed

Dassonville, C; Demattei, C; Laurent, A-M; Le Moullec, Y; Seta, N; Momas, I

2009-08-01

Exposure to indoor chemical air pollutants expected to be potentially involved in allergic respiratory diseases in infants is poorly documented. A specific environmental investigation included in a birth cohort study was carried out to first assess indoor airborne aldehyde levels, using passive devices and their variability within 1 year (1, 6, 9 and 12 months) in the bedroom of 196 Paris infants, and second, to identify predictors for aldehyde concentrations using interviewer administered questionnaires about housing factors. Comfort parameters and carbon dioxide levels were measured simultaneously. Aldehydes were detected in almost all dwellings and geometric mean levels (geometric standard deviation) at the first visit were respectively for formaldehyde, acetaldehyde, hexanal, and pentanal 19.4 (1.7) microg/m(3), 8.9 (1.8) microg/m(3), 25.3 (3.1) microg/m(3), 3.7 (2.3) microg/m(3), consistent with earlier published results. Generalized Estimating Equation multivariate analyses showed that, apart from comfort parameters, aeration and season, the main indoor aldehyde sources were either continuous (building materials and coverings especially when they were new) or discontinuous (smoking, use of air fresheners and cleaning products, DIY etc...). Finally, the data collected by questionnaires should be sufficient to enable us to classify each infant in our cohort study according to his/her degree of exposure to the main aldehydes. This analysis contributed to document indoor aldehyde levels in Parisian homes and to identify factors determining these levels. In the major part of newborn babies' homes, indoor formaldehyde levels were above the guideline value of 10 microg/m(3) proposed by the French Agency for Environmental and Occupational Health Safety for long-term exposure. Given this result, it is essential to study the health impact of exposure to aldehydes especially formaldehyde on the incidence of respiratory and allergic symptoms, particularly during the first months of life.

Trends in oral drug bioavailability following bariatric surgery: examining the variable extent of impact on exposure of different drug classes.

PubMed

Darwich, Adam S; Henderson, Kathryn; Burgin, Angela; Ward, Nicola; Whittam, Janet; Ammori, Basil J; Ashcroft, Darren M; Rostami-Hodjegan, Amin

2012-11-01

Changes to oral drug bioavailability have been observed post bariatric surgery. However, the magnitude and the direction of changes have not been assessed systematically to provide insights into the parameters governing the observed trends. Understanding these can help with dose adjustments. Analysis of drug characteristics based on a biopharmaceutical classification system is not adequate to explain observed trends in altered oral drug bioavailability following bariatric surgery, although the findings suggest solubility to play an important role. To identify the most commonly prescribed drugs in a bariatric surgery population and to assess existing evidence regarding trends in oral drug bioavailability post bariatric surgery. A retrospective audit was undertaken to document commonly prescribed drugs amongst patients undergoing bariatric surgery in an NHS hospital in the UK and to assess practice for drug administration following bariatric surgery. The available literature was examined for trends relating to drug permeability and solubility with regards to the Biopharmaceutics Classification System (BCS) and main route of elimination. No significant difference in the 'post/pre surgery oral drug exposure ratio' (ppR) was apparent between BCS class I to IV drugs, with regards to dose number (Do) or main route of elimination. Drugs classified as 'solubility limited' displayed an overall reduction as compared with 'freely soluble' compounds, as well as an unaltered and increased ppR. Clinical studies establishing guidelines for commonly prescribed drugs, and the monitoring of drugs exhibiting a narrow therapeutic window or without a readily assessed clinical endpoint, are warranted. Using mechanistically based pharmacokinetic modelling for simulating the multivariate nature of changes in drug exposure may serve as a useful tool in the further understanding of postoperative trends in oral drug exposure and in developing practical clinical guidance. © 2012 The Authors. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

EXPOSURE RELATIONSHIP OF PERSONAL EXPOSURE OF HIGH-RISK SUBPOPULATIONS TO AMBIENT CONCENTRATIONS OF FINE PARTICLES.

EPA Science Inventory

An association has been demonstrated between ambient particulate matter (PM 2.5 and PM 10) concentrations and human morbidity/mortality. However, little is known regarding the most important sources of PM exposure, interpersonal and intrapersonal variability in exposure, and the...

Secondhand tobacco smoke exposure and pulmonary function: a cross-sectional study among non-smoking employees of bar and restaurants in Santiago, Chile.

PubMed

Parro, Javiera; Aceituno, Paulina; Droppelmann, Andrea; Mesías, Sthepanie; Muñoz, Claudio; Marchetti, Nella; Iglesias, Verónica

2017-10-06

The workplace remains a significant source of secondhand smoke (SHS) exposure. This pollutant is known to be associated with respiratory and cardiovascular problems, but its effects on specific pulmonary function parameters remain largely unexplored. The objectives of this study were to measure SHS exposure among non-smoking employees of bar and restaurants in Santiago, Chile and to evaluate the effects of such exposure on pulmonary function. Cross-sectional design. The study sample included non-smoking workers from 57 restaurants and bars in Santiago, Chile. The outcome variable was pulmonary function and the exposure variables were urine cotinine concentration, a biomarker for current SHS exposure, and years of SHS exposure in the workplace as proxy of chronic exposure. Personal and occupational variables were also recorded. Data analysis was performed using linear regression models adjusted by confounders. The median age of the workers was 35 years and the median employment duration at the analysed venues was 1 year. Workers in smoking facilities reported greater SHS exposure (36 hours per week) than workers in smoke-free locations (4 hours per week). Urine cotinine levels were inversely correlated with forced vital capacity, but the finding was not statistically significant (β=-0.0002; 95% CI -0.007 to 0.006). Years of exposure to SHS showed to be significantly associated with forced expiratory flow 25/75 (β=-0.006; 95% CI -0.010 to -0.0004). These findings suggest that cumulative exposure to SHS at work may contribute to deterioration of pulmonary function in non-smoking employees. © 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.

Combination of a higher-tier flow-through system and population modeling to assess the effects of time-variable exposure of isoproturon on the green algae Desmodesmus subspicatus and Pseudokirchneriella subcapitata.

PubMed

Weber, Denis; Schaefer, Dieter; Dorgerloh, Michael; Bruns, Eric; Goerlitz, Gerhard; Hammel, Klaus; Preuss, Thomas G; Ratte, Hans Toni

2012-04-01

A flow-through system was developed to investigate the effects of time-variable exposure of pesticides on algae. A recently developed algae population model was used for simulations supported and verified by laboratory experiments. Flow-through studies with Desmodesmus subspicatus and Pseudokirchneriella subcapitata under time-variable exposure to isoproturon were performed, in which the exposure patterns were based on the results of FOrum for Co-ordination of pesticide fate models and their USe (FOCUS) model calculations for typical exposure situations via runoff or drain flow. Different types of pulsed exposure events were realized, including a whole range of repeated pulsed and steep peaks as well as periods of constant exposure. Both species recovered quickly in terms of growth from short-term exposure and according to substance dissipation from the system. Even at a peak 10 times the maximum predicted environmental concentration of isoproturon, only transient effects occurred on algae populations. No modified sensitivity or reduced growth was observed after repeated exposure. Model predictions of algal growth in the flow-through tests agreed well with the experimental data. The experimental boundary conditions and the physiological properties of the algae were used as the only model input. No calibration or parameter fitting was necessary. The combination of the flow-through experiments with the algae population model was revealed to be a powerful tool for the assessment of pulsed exposure on algae. It allowed investigating the growth reduction and recovery potential of algae after complex exposure, which is not possible with standard laboratory experiments alone. The results of the combined approach confirm the beneficial use of population models as supporting tools in higher-tier risk assessments of pesticides. Copyright © 2012 SETAC.

Secondhand tobacco smoke exposure and pulmonary function: a cross-sectional study among non-smoking employees of bar and restaurants in Santiago, Chile

PubMed Central

Parro, Javiera; Aceituno, Paulina; Droppelmann, Andrea; Mesías, Sthepanie; Muñoz, Claudio; Marchetti, Nella; Iglesias, Verónica

2017-01-01

Introduction The workplace remains a significant source of secondhand smoke (SHS) exposure. This pollutant is known to be associated with respiratory and cardiovascular problems, but its effects on specific pulmonary function parameters remain largely unexplored. The objectives of this study were to measure SHS exposure among non-smoking employees of bar and restaurants in Santiago, Chile and to evaluate the effects of such exposure on pulmonary function. Methods Cross-sectional design. The study sample included non-smoking workers from 57 restaurants and bars in Santiago, Chile. The outcome variable was pulmonary function and the exposure variables were urine cotinine concentration, a biomarker for current SHS exposure, and years of SHS exposure in the workplace as proxy of chronic exposure. Personal and occupational variables were also recorded. Data analysis was performed using linear regression models adjusted by confounders. Results The median age of the workers was 35 years and the median employment duration at the analysed venues was 1 year. Workers in smoking facilities reported greater SHS exposure (36 hours per week) than workers in smoke-free locations (4 hours per week). Urine cotinine levels were inversely correlated with forced vital capacity, but the finding was not statistically significant (β=−0.0002; 95% CI −0.007 to 0.006). Years of exposure to SHS showed to be significantly associated with forced expiratory flow25/75 (β=−0.006; 95% CI −0.010 to −0.0004). Conclusion These findings suggest that cumulative exposure to SHS at work may contribute to deterioration of pulmonary function in non-smoking employees. PMID:28988182

Temporal variability in urinary levels of drinking water disinfection byproducts dichloroacetic acid and trichloroacetic acid among men

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

Wang, Yi-Xin; Zeng, Qiang; Wang, Le

Urinary haloacetic acids (HAAs), such as dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), have been suggested as potential biomarkers of exposure to drinking water disinfection byproducts (DBPs). However, variable exposure to and the short elimination half-lives of these biomarkers can result in considerable variability in urinary measurements, leading to exposure misclassification. Here we examined the variability of DCAA and TCAA levels in the urine among eleven men who provided urine samples on 8 days over 3 months. The urinary concentrations of DCAA and TCAA were measured by gas chromatography coupled with electron capture detection. We calculated the intraclass correlation coefficientsmore » (ICCs) to characterize the within-person and between-person variances and computed the sensitivity and specificity to assess how well single or multiple urine collections accurately determined personal 3-month average DCAA and TCAA levels. The within-person variance was much higher than the between-person variance for all three sample types (spot, first morning, and 24-h urine samples) for DCAA (ICC=0.08–0.37) and TCAA (ICC=0.09–0.23), regardless of the sampling interval. A single-spot urinary sample predicted high (top 33%) 3-month average DCAA and TCAA levels with high specificity (0.79 and 0.78, respectively) but relatively low sensitivity (0.47 and 0.50, respectively). Collecting two or three urine samples from each participant improved the classification. The poor reproducibility of the measured urinary DCAA and TCAA concentrations indicate that a single measurement may not accurately reflect individual long-term exposure. Collection of multiple urine samples from one person is an option for reducing exposure classification errors in studies exploring the effects of DBP exposure on reproductive health. - Highlights: • We evaluated the variability of DCAA and TCAA levels in the urine among men. • Urinary DCAA and TCAA levels varied greatly over a 3-month period. • Single measurement may not accurately reflect personal long-term exposure levels. • Collecting multiple samples from one person improved the exposure classification.« less

Influence of maternal and own genotype at tanning dependence-related SNPs on sun exposure in childhood.

PubMed

Khouja, Jasmine; Lewis, Sarah J; Bonilla, Carolina

2018-04-12

Research suggests there may be a genetic influence on the likelihood of becoming tanning dependent (TD). The way in which mothers regulate their children's sun exposure may be affected by being TD. We investigated the associations between single nucleotide polymorphisms (SNPs) related to being TD and early sun exposure. Data from the Avon Longitudinal Study of Parents and Children (ALSPAC) were used. Associations between 17 TD related SNPs in children and their mothers and 10 sun exposure variables in children (assessed via questionnaire at age 8) were analyzed in logistic and ordinal logistic regressions. Analyses were adjusted for principal components of population structure and age (at time of questionnaire response). Models with additional adjustment for maternal or offspring genotypes were also tested. Secondary analyses included adjustment for sex and skin pigmentation. Among ALSPAC children, the rs29132 SNP in the Vesicle-associated membrane protein-associated protein A (VAPA) gene was associated with five sun exposure variables whilst the rs650662 SNP in the Opioid Receptor Mu 1 (OPRM1) gene was associated with three. The remaining SNPs did not show associations beyond what was expected by chance. After Bonferroni correction one SNP in the children was associated with an increased likelihood of using sun cream whilst in the sun at 8 years old (rs60050811 in the Spermatogenesis and Centriole Associated 1 (SPATC1) gene, OR per C allele = 1.34, 95% CI 1.11-1.62, p = .003). In the mothers, rs650662 in OPRM1 was associated with the use of a lower factor of sun cream in their children, (OR per A allele = 0.89, 95% CI 0.82-0.96, p = .002). Whilst rs2073478 in the Aldehyde Dehydrogenase 1 Family Member B1 (ALDH1B1) gene was associated with a reduced odds of their child using a sun block or cream with a 4 star rating (OR per T allele = 0.68, 95% CI 0.53-0.88, p = .003). Similar but weaker associations were observed for the main findings in the secondary analyses. We found weak evidence to suggest that genes previously associated with TD are associated with sun exposure in children of European ancestry from southwest England.

Exposure misclassification due to residential mobility during pregnancy.

PubMed

Hodgson, Susan; Lurz, Peter W W; Shirley, Mark D F; Bythell, Mary; Rankin, Judith

2015-06-01

Pregnant women are a highly mobile group, yet studies suggest exposure error due to migration in pregnancy is minimal. We aimed to investigate the impact of maternal residential mobility on exposure to environmental variables (urban fabric, roads and air pollution (PM10 and NO₂)) and socio-economic factors (deprivation) that varied spatially and temporally. We used data on residential histories for deliveries at ≥ 24 weeks gestation recorded by the Northern Congenital Abnormality Survey, 2000-2008 (n=5399) to compare: (a) exposure at conception assigned to maternal postcode at delivery versus maternal postcode at conception, and (b) exposure at conception assigned to maternal postcode at delivery versus mean exposure based on residences throughout pregnancy. In this population, 24.4% of women moved during pregnancy. Depending on the exposure variable assessed, 1-12% of women overall were assigned an exposure at delivery >1 SD different to that at conception, and 2-25% assigned an exposure at delivery >1 SD different to the mean exposure throughout pregnancy. To meaningfully explore the subtle associations between environmental exposures and health, consideration must be given to error introduced by residential mobility. Copyright © 2015 The Authors. Published by Elsevier GmbH.. All rights reserved.

Commuter exposure to ultrafine particles in different urban locations, transportation modes and routes

NASA Astrophysics Data System (ADS)

Ragettli, Martina S.; Corradi, Elisabetta; Braun-Fahrländer, Charlotte; Schindler, Christian; de Nazelle, Audrey; Jerrett, Michael; Ducret-Stich, Regina E.; Künzli, Nino; Phuleria, Harish C.

2013-10-01

A better understanding of ultrafine particle (UFP) exposure in different urban transport microenvironments is important for epidemiological exposure assessments and for policy making. Three sub-studies were performed to characterize personal exposure to UFP concentration and average particle size distribution diameters in frequently traveled commuter microenvironments in the city of Basel, Switzerland. First, the spatial variation of sidewalk UFP exposures within urban areas and transport-specific microenvironments was explored. Second, exposure to UFP concentration and average particle size were quantified for five modes of transportation (walking, bicycle, bus, tram, car) during different times of the day and week, along the same route. Finally, the contribution of bicycle commuting along two different routes (along main roads, away from main roads) to total daily exposures was assessed by 24-h personal measurements. In general, smaller average particle sizes and higher UFP levels were measured at places and for travel modes in close proximity to traffic. Average trip UFP concentrations were higher in car (31,784 particles cm-³) and on bicycle (22,660 particles cm-³) compared to walking (19,481 particles cm-³) and public transportation (14,055-18,818 particles cm-³). Concentrations were highest for all travel modes during weekday morning rush hours, compared to other time periods. UFP concentration was lowest in bus, regardless of time period. Bicycle travel along main streets between home and work place (24 min on average) contributed 21% and 5% to total daily UFP exposure in winter and summer, respectively. Contribution of bicycle commutes to total daily UFP exposure could be reduced by half if main roads are avoided. Our results show the importance of considering commuter behavior and route choice in exposure assessment studies.

Application of alternative spatiotemporal metrics of ambient air pollution exposure in a time-series epidemiological study in Atlanta

EPA Science Inventory

Exposure error in studies of ambient air pollution and health that use city-wide measures of exposure may be substantial for pollutants that exhibit spatiotemporal variability. Alternative spatiotemporal metrics of exposure for traffic-related and regional pollutants were applied...

ALTERNATIVE EXPOSURE MEASUREMENT DESIGNS TO IMPROVE EPIDEMIOLOGICAL STUDY DESIGNS: DETERMINANTS OF TEMPORAL VARIABILITY IN ENVIRONMENTAL CONCENTRATIONS, EXPOSURES, AND BIOMARKERS

EPA Science Inventory

The National Human Exposure Assessment Survey in Maryland (NHEXAS-MD) was a longitudinal study of multimedia exposure to metals, pesticides, and polycyclic aromatic compounds (PAHs). Measurements were made and questionnaires were concurrently administered to identify sources o...

ANALYSIS OF DISCRIMINATING FACTORS IN HUMAN ACTIVITIES THAT AFFECT EXPOSURE

EPA Science Inventory

Accurately modeling exposure to particulate matter (PM) and other pollutants ultimately involves the utilization of human location-activity databases to assist in understanding the potential variability of microenvironmental exposures. This paper critically considers and stati...

Exposure Science and Its Applications for Effective Environmental Management

EPA Science Inventory

Exposure is the link between environmental pollution and human/ecosystem health. Exposure science entails understanding the scientific processes that affect source emissions, transport and fate, spatio-temporal variability in the ambient concentrations, levels of contaminants tha...

Cognitive ability and risk of post-traumatic stress disorder after military deployment: an observational cohort study

PubMed Central

Karstoft, Karen-Inge; Vedtofte, Mia S.; Nielsen, Anni B.S.; Osler, Merete; Mortensen, Erik L.; Christensen, Gunhild T.; Andersen, Søren B.

2017-01-01

Background Studies of the association between pre-deployment cognitive ability and post-deployment post-traumatic stress disorder (PTSD) have shown mixed results. Aims To study the influence of pre-deployment cognitive ability on PTSD symptoms 6–8 months post-deployment in a large population while controlling for pre-deployment education and deployment-related variables. Method Study linking prospective pre-deployment conscription board data with post-deployment self-reported data in 9695 Danish Army personnel deployed to different war zones in 1997–2013. The association between pre-deployment cognitive ability and post-deployment PTSD was investigated using repeated-measure logistic regression models. Two models with cognitive ability score as the main exposure variable were created (model 1 and model 2). Model 1 was only adjusted for pre-deployment variables, while model 2 was adjusted for both pre-deployment and deployment-related variables. Results When including only variables recorded pre-deployment (cognitive ability score and educational level) and gender (model 1), all variables predicted post-deployment PTSD. When deployment-related variables were added (model 2), this was no longer the case for cognitive ability score. However, when educational level was removed from the model adjusted for deployment-related variables, the association between cognitive ability and post-deployment PTSD became significant. Conclusions Pre-deployment lower cognitive ability did not predict post-deployment PTSD independently of educational level after adjustment for deployment-related variables. Declaration of interest None. Copyright and usage © The Royal College of Psychiatrists 2017. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license. PMID:29163983

Determinants of wood dust exposure in the Danish furniture industry.

PubMed

Mikkelsen, Anders B; Schlunssen, Vivi; Sigsgaard, Torben; Schaumburg, Inger

2002-11-01

This paper investigates the relation between wood dust exposure in the furniture industry and occupational hygiene variables. During the winter 1997-98 54 factories were visited and 2362 personal, passive inhalable dust samples were obtained; the geometric mean was 0.95 mg/m(3) and the geometric standard deviation was 2.08. In a first measuring round 1685 dust concentrations were obtained. For some of the workers repeated measurements were carried out 1 (351) and 2 weeks (326) after the first measurement. Hygiene variables like job, exhaust ventilation, cleaning procedures, etc., were documented. A multivariate analysis based on mixed effects models was used with hygiene variables being fixed effects and worker, machine, department and factory being random effects. A modified stepwise strategy of model making was adopted taking into account the hierarchically structured variables and making possible the exclusion of non-influential random as well as fixed effects. For woodworking, the following determinants of exposure increase the dust concentration: manual and automatic sanding and use of compressed air with fully automatic and semi-automatic machines and for cleaning of work pieces. Decreased dust exposure resulted from the use of compressed air with manual machines, working at fully automatic or semi-automatic machines, functioning exhaust ventilation, work on the night shift, daily cleaning of rooms, cleaning of work pieces with a brush, vacuum cleaning of machines, supplementary fresh air intake and safety representative elected within the last 2 yr. For handling and assembling, increased exposure results from work at automatic machines and presence of wood dust on the workpieces. Work on the evening shift, supplementary fresh air intake, work in a chair factory and special cleaning staff produced decreased exposure to wood dust. The implications of the results for the prevention of wood dust exposure are discussed.

Digging in the coronal graveyard - A Rosat observation of the red giant Arcturus

NASA Technical Reports Server (NTRS)

Ayres, Thomas R.; Fleming, Thomas A.; Schmitt, Juergen H. M. M.

1991-01-01

A deep exposure of the bright star Arcturus (Alpha Bootis: K1 III) with the Roentgensatellit (Rosat) failed to detect soft X-ray emission from the archetype 'noncoronal' red giant. The 3-sigma upper limit in the energy band 0.1-2.4 keV corresponds to an X-ray luminosity of less than 3 x 10 to the 25th erg/s, equivalent to a coronal surface flux density of less than 0.0001 solar. The nondetection safely eliminates coronal irradiation as a possible mechanism to produce the highly variable He I 10830 feature and emphasizes the sharp decline in solarlike coronal activity that accompanies the evolution of low-mass single stars away from the main sequence. While the most conspicuous object in the Rosat field of view was not visible in X-rays, at least one fainter star is among the about 60 sources recorded: the Sigma Sct variable CN Boo, an A8 giant in the UMa Stream.

Evaluation of water treatment sludges toxicity using the Daphnia bioassay.

PubMed

Sotero-Santos, Rosana B; Rocha, Odete; Povinelli, Jurandyr

2005-10-01

Alum and ferric chloride sludges from two water treatment plants (WTPs) were analyzed regarding their physicochemical characteristics and toxicity to Daphnia similis. Experiments were carried out in the dry and rainy seasons. Acute and chronic toxicity was measured using survival and reproduction as measurement endpoints. No acute toxicity of the sludge was observed in 48 h exposure. Ferric chloride sludge caused chronic toxicity, demonstrated by low fecundity and some mortality, while alum sludge caused chronic toxicity characterized by low fecundity. Some sludge characteristics varied between samplings, including turbidity, solids contents, N, P and metal (Al and Fe) concentrations. These variables and the increase of chemical oxygen demand (COD) were identified as the main cause of degradation of the receiving waters. However, no relationship was observed between these variables and degree of toxicity. It is apparent from these results that water treatment sludges may be toxic and therefore may impair receiving waters. Alum sludge was less toxic than ferric chloride sludge.

Within-city contrasts in PM composition and sources and their relationship with nitrogen oxides.

PubMed

Minguillón, M C; Rivas, I; Aguilera, I; Alastuey, A; Moreno, T; Amato, F; Sunyer, J; Querol, X

2012-10-26

The present work is part of the INMA (INfancia y Medio Ambiente -'Environment and Childhood') project, which aims at assessing the adverse effects of exposure to air pollution during pregnancy and early in life. The present study was performed in the city of Sabadell (Northeast Spain) at three sampling sites covering different traffic characteristics, during two times of the year. It assesses time and spatial variations of PM(2.5) concentrations, chemical components and source contributions, as well as gaseous pollutants. Furthermore, a cross-correlation analysis of PM components and source contributions with gaseous pollutants used as a proxy for exposure assessment is carried out. Our data show the influence of traffic emissions in the Sabadell area. The main PM sources identified by Positive Matrix Factorisation (PMF) were similar between the two seasons: mineral source (traffic-induced resuspension, demolition/construction and natural background), secondary sulphate (higher in summer), secondary nitrate (only during winter), industrial, and road traffic, which was the main contributor to PM(2.5) at two of the sites. The correlation of concentrations of nitrogen oxides was especially strong with those of elemental carbon (EC). The relatively weaker correlations with organic carbon (OC) in summer are attributed to the variable formation of secondary OC. Strong correlations between concentration of nitrogen oxides and PM(2.5) road traffic contributions obtained from source apportionment analysis were seen at all sites. Therefore, under the studied urban environment, nitrogen oxides can be used as a proxy for the exposure to road traffic contribution to PM(2.5); the use of NO(x) concentrations being preferred, with NO and NO(2) as second and third options, respectively.

Cognitive factors contributing to spelling performance in children with prenatal alcohol exposure.

PubMed

Glass, Leila; Graham, Diana M; Akshoomoff, Natacha; Mattson, Sarah N

2015-11-01

Heavy prenatal alcohol exposure is associated with impaired school functioning. Spelling performance has not been comprehensively evaluated. We examined whether children with heavy prenatal alcohol exposure demonstrate deficits in spelling and related abilities, including reading, and tested whether there are unique underlying mechanisms for observed deficits in this population. Ninety-six school-age children made up 2 groups: children with heavy prenatal alcohol exposure (AE, n = 49) and control children (CON, n = 47). Children completed select subtests from the Wechsler Individual Achievement Test-Second Edition and the NEPSY-II. Group differences and relations between spelling and theoretically related cognitive variables were evaluated using multivariate analysis of variance and Pearson correlations. Hierarchical regression analyses were used to assess contributions of group membership and cognitive variables to spelling performance. The specificity of these deficits and underlying mechanisms was tested by examining the relations between reading ability, group membership, and cognitive variables. Groups differed significantly on all variables. Group membership and phonological processing significantly contributed to spelling performance, whereas for reading, group membership and all cognitive variables contributed significantly. For both reading and spelling, group × working memory interactions revealed that working memory contributed independently only for alcohol-exposed children. Alcohol-exposed children demonstrated a unique pattern of spelling deficits. The relation of working memory to spelling and reading was specific to the AE group, suggesting that if prenatal alcohol exposure is known or suspected, working memory ability should be considered in the development and implementation of explicit instruction. (c) 2015 APA, all rights reserved).

Influence of internal variability on population exposure to hydroclimatic changes

NASA Astrophysics Data System (ADS)

Mankin, Justin S.; Viviroli, Daniel; Mekonnen, Mesfin M.; Hoekstra, Arjen Y.; Horton, Radley M.; E Smerdon, Jason; Diffenbaugh, Noah S.

2017-04-01

Future freshwater supply, human water demand, and people’s exposure to water stress are subject to multiple sources of uncertainty, including unknown future pathways of fossil fuel and water consumption, and ‘irreducible’ uncertainty arising from internal climate system variability. Such internal variability can conceal forced hydroclimatic changes on multi-decadal timescales and near-continental spatial-scales. Using three projections of population growth, a large ensemble from a single Earth system model, and assuming stationary per capita water consumption, we quantify the likelihoods of future population exposure to increased hydroclimatic deficits, which we define as the average duration and magnitude by which evapotranspiration exceeds precipitation in a basin. We calculate that by 2060, ∽31%-35% of the global population will be exposed to >50% probability of hydroclimatic deficit increases that exceed existing hydrological storage, with up to 9% of people exposed to >90% probability. However, internal variability, which is an irreducible uncertainty in climate model predictions that is under-sampled in water resource projections, creates substantial uncertainty in predicted exposure: ∽86%-91% of people will reside where irreducible uncertainty spans the potential for both increases and decreases in sub-annual water deficits. In one population scenario, changes in exposure to large hydroclimate deficits vary from -3% to +6% of global population, a range arising entirely from internal variability. The uncertainty in risk arising from irreducible uncertainty in the precise pattern of hydroclimatic change, which is typically conflated with other uncertainties in projections, is critical for climate risk management that seeks to optimize adaptations that are robust to the full set of potential real-world outcomes.

Cognitive Factors Contributing to Spelling Performance in Children with Prenatal Alcohol Exposure

PubMed Central

Glass, Leila; Graham, Diana M.; Akshoomoff, Natacha; Mattson, Sarah N.

2015-01-01

Objective Heavy prenatal alcohol exposure is associated with impaired school functioning. Spelling performance has not been comprehensively evaluated. We examined whether children with heavy prenatal alcohol exposure demonstrate deficits in spelling and related abilities, including reading, and tested whether there are unique underlying mechanisms for observed deficits in this population. Method Ninety-six school-age children comprised two groups: children with heavy prenatal alcohol exposure (AE, n=49) and control children (CON, n=47). Children completed select subtests from the WIAT-II and NEPSY-II. Group differences and relations between spelling and theoretically-related cognitive variables were evaluated using MANOVA and Pearson correlations. Hierarchical regression analyses were utilized to assess contributions of group membership and cognitive variables to spelling performance. The specificity of these deficits and underlying mechanisms was tested by examining the relations between reading ability, group membership, and cognitive variables. Results Groups differed significantly on all variables. Group membership and phonological processing significantly contributed to spelling performance. In addition, a significant group*working memory interaction revealed that working memory independently contributed significantly to spelling only for the AE group. All cognitive variables contributed to reading across groups and a group*working memory interaction revealed that working memory contributed independently to reading only for alcohol-exposed children. Conclusion Alcohol-exposed children demonstrated a unique pattern of spelling deficits. The relation of working memory to spelling and reading was specific to the AE group, suggesting that if prenatal alcohol exposure is known or suspected, working memory ability should be considered in the development and implementation of explicit instruction. PMID:25643217

[Third working conditions and health survey in Navarre, Spain: main findings].

PubMed

García, Vega

To describe health problems and working conditions perceived by workers of Navarra, Spain. Conduct of the Third Survey of Working Conditions and Health in Navarre. We administered the Seventh Spanish National Survey of Working Conditions questionnaire by personal interviews conducted in the workers' homes between October 2014 and December 2014, and using a three-stage stratified sampling approach, by economic activity, work establishment size and gender. A total of 2744 interviews were completed, with a confidence level of 95.5% and P=Q, error ± 1.99. The analysis was weighted by the sampling variables. The results were summarized as percentages for qualitative variables and point estimates for quantitative variables. Among the postivie findings, 85% of respondents were well informed of job risks, 68% had access to a health and safety representative, 50% underwent risk assessments and 60% received periodic medical examinations. Among the notable self-reported occupational risk factors were exposure to loud noise (16%), chemicals (33%), accident-prone situations (76%), repetitive movements (62%), awkward postures (41%) and biological agents (11%). Issues of concern include a high percentage of overtime work (44% of men and 39% of women), feelings of being overworked (30.6% and 29.4%, respectively) and exposure to abusive behaviors (11.7% for verbal abuse), especially among women, healthcare workers and teachers. The most prevalent health problems were musculoskeletal (49% reporting back pain) and issues related to work stress (20%). The current working conditions in Navarre feature improved preventive services, persistence of traditional occupational risk factors and emergence of new issues such as violence and work stressors. Copyright belongs to the Societat Catalana de Salut Laboral.

A structural equation model of soil metal bioavailability to earthworms: confronting causal theory and observations using a laboratory exposure to field-contaminated soils.

PubMed

Beaumelle, Léa; Vile, Denis; Lamy, Isabelle; Vandenbulcke, Franck; Gimbert, Frédéric; Hedde, Mickaël

2016-11-01

Structural equation models (SEM) are increasingly used in ecology as multivariate analysis that can represent theoretical variables and address complex sets of hypotheses. Here we demonstrate the interest of SEM in ecotoxicology, more precisely to test the three-step concept of metal bioavailability to earthworms. The SEM modeled the three-step causal chain between environmental availability, environmental bioavailability and toxicological bioavailability. In the model, each step is an unmeasured (latent) variable reflected by several observed variables. In an exposure experiment designed specifically to test this SEM for Cd, Pb and Zn, Aporrectodea caliginosa was exposed to 31 agricultural field-contaminated soils. Chemical and biological measurements used included CaC12-extractable metal concentrations in soils, free ion concentration in soil solution as predicted by a geochemical model, dissolved metal concentration as predicted by a semi-mechanistic model, internal metal concentrations in total earthworms and in subcellular fractions, and several biomarkers. The observations verified the causal definition of Cd and Pb bioavailability in the SEM, but not for Zn. Several indicators consistently reflected the hypothetical causal definition and could thus be pertinent measurements of Cd and Pb bioavailability to earthworm in field-contaminated soils. SEM highlights that the metals present in the soil solution and easily extractable are not the main source of available metals for earthworms. This study further highlights SEM as a powerful tool that can handle natural ecosystem complexity, thus participating to the paradigm change in ecotoxicology from a bottom-up to a top-down approach. Copyright © 2016 Elsevier B.V. All rights reserved.

A prospective cohort study to evaluate peridomestic infection as a determinant of dengue transmission: Protocol

PubMed Central

2012-01-01

Background Vector control programs, which have focused mainly on the patient house and peridomestic areas around dengue cases, have not produced the expected impact on transmission. This project will evaluate the assumption that the endemic/epidemic transmission of dengue begins around peridomestic vicinities of the primary cases. Its objective is to assess the relationship between symptomatic dengue case exposure and peridomestic infection incidence. Methods/Design A prospective cohort study will be conducted (in Tepalcingo and Axochiapan, in the state of Morelos, Mexico), using the state surveillance system for the detection of incident cases. Paired blood specimens will be collected from both the individuals who live with the incident cases and a sample of subjects residing within a 25-meter radius of such cases (exposed cohort), in order to measure dengue-specific antibodies. Other subjects will be selected from areas which have not presented any incident cases within 200 meters, during the two months preceding the sampling (non-exposed cohort). Symptomatic/asymptomatic incident infection will be considered as the dependent variable, exposure to confirmed dengue cases, as the principal variable, and the socio-demographic, environmental and socio-cultural conditions of the subjects, as additional explanatory variables. Discussion Results indicating a high infection rate among the exposed subjects would justify the application of peridomestic control measures and call for an evaluation of alternate causes for insufficient program impact. On the other hand, a low incidence of peridomestic-infected subjects would support the hypothesis that infection occurs outside the domicile, and would thus explain why the vector control measures applied in the past have exerted such a limited impact on cases incidence rates. The results of the present study may therefore serve to reassess site selection for interventions of this type. PMID:22471857

Gender Differences in the Association of Individual and Contextual Exposures with Lung Function in a Rural Canadian Population.

PubMed

Janzen, Bonnie; Karunanayake, Chandima; Rennie, Donna; Pickett, William; Lawson, Joshua; Kirychuk, Shelley; Hagel, Louise; Senthilselvan, Ambikaipakan; Koehncke, Niels; Dosman, James; Pahwa, Punam

2017-02-01

To investigate the association of individual and contextual exposures with lung function by gender in rural-dwelling Canadians. A cross-sectional mail survey obtained completed questionnaires on exposures from 8263 individuals; a sub-sample of 1609 individuals (762 men, 847 women) additionally participated in clinical lung function testing. The three dependent variables were forced expired volume in one second (FEV 1 ), forced vital capacity (FVC), and FEV 1 /FVC ratio. Independent variables included smoking, waist circumference, body mass index, indoor household exposures (secondhand smoke, dampness, mold, musty odor), occupational exposures (grain dust, pesticides, livestock, farm residence), and socioeconomic status. The primary analysis was multiple linear regression, conducted separately for each outcome. The potential modifying influence of gender was tested in multivariable models using product terms between gender and each independent variable. High-risk waist circumference was related to reduced FVC and FEV 1 for both genders, but the effect was more pronounced in men. Greater pack-years smoking was associated with lower lung function values. Exposure to household smoke was related to reduced FEV 1 , and exposure to livestock, with increased FEV 1 . Lower income adequacy was associated with reduced FVC and FEV 1 . High-risk waist circumference was more strongly associated with reduced lung function in men than women. Longitudinal research combined with rigorous exposure assessment is needed to clarify how sex and gender interact to impact lung function in rural populations.

Early Changes in Clinical, Functional, and Laboratory Biomarkers in Workers at Risk of Indium Lung Disease

PubMed Central

Virji, M. Abbas; Trapnell, Bruce C.; Carey, Brenna; Healey, Terrance; Kreiss, Kathleen

2014-01-01

Rationale: Occupational exposure to indium compounds, including indium–tin oxide, can result in potentially fatal indium lung disease. However, the early effects of exposure on the lungs are not well understood. Objectives: To determine the relationship between short-term occupational exposures to indium compounds and the development of early lung abnormalities. Methods: Among indium–tin oxide production and reclamation facility workers, we measured plasma indium, respiratory symptoms, pulmonary function, chest computed tomography, and serum biomarkers of lung disease. Relationships between plasma indium concentration and health outcome variables were evaluated using restricted cubic spline and linear regression models. Measurements and Main Results: Eighty-seven (93%) of 94 indium–tin oxide facility workers (median tenure, 2 yr; median plasma indium, 1.0 μg/l) participated in the study. Spirometric abnormalities were not increased compared with the general population, and few subjects had radiographic evidence of alveolar proteinosis (n = 0), fibrosis (n = 2), or emphysema (n = 4). However, in internal comparisons, participants with plasma indium concentrations ≥ 1.0 μg/l had more dyspnea, lower mean FEV1 and FVC, and higher median serum Krebs von den Lungen-6 and surfactant protein-D levels. Spline regression demonstrated nonlinear exposure response, with significant differences occurring at plasma indium concentrations as low as 1.0 μg/l compared with the reference. Associations between health outcomes and the natural log of plasma indium concentration were evident in linear regression models. Associations were not explained by age, smoking status, facility tenure, or prior occupational exposures. Conclusions: In indium–tin oxide facility workers with short-term, low-level exposure, plasma indium concentrations lower than previously reported were associated with lung symptoms, decreased spirometric parameters, and increased serum biomarkers of lung disease. PMID:25295756

Compliance with universal precautions in correctional health care facilities.

PubMed

Gershon, R R; Karkashian, C D; Vlahov, D; Kummer, L; Kasting, C; Green-McKenzie, J; Escamilla-Cejudo, J A; Kendig, N; Swetz, A; Martin, L

1999-03-01

There were three main objectives of this cross-sectional study of Maryland State correctional health care workers. The first was to evaluate compliance with work practices designed to minimize exposure to blood and body fluids; the second, to identify correlates of compliance with universal precautions (UPs); and the third was to determine the relationship, if any, between compliance and exposures. Of 216 responding health care workers, 34% reported overall compliance across all 15 items on a compliance scale. Rates for specific items were particularly low for use of certain types of personal protective equipment, such as protective eyewear (53.5%), face mask (47.2%) and protective clothing (33.9%). Compliance rates were highest for glove use (93.2%) waste disposal (89.8%), and sharps disposal (80.8%). Compliance rates were generally not associated with demographic factors, except for age; younger workers were more likely to be compliant with safe work practices than were older workers (P < 0.05). Compliance was positively associated with several work-related variables, including perceived safety climate (i.e., management's commitment to infection control and the overall safety program) and job satisfaction, and was found to be inversely associated with security-related work constraints, job/task factors, adverse working conditions, workplace discrimination, and perceived work stress. Bloodborne exposures were not uncommon; 13.8% of all respondents had at least one bloodborne exposure within the previous 6 months, and compliance was inversely related to blood and body fluid exposures. This study identified several potentially modifiable correlates of compliance, including factors unique to the correctional setting. Infection-control interventional strategies specifically tailored to these health care workers may therefore be most effective in reducing the risk of bloodborne exposures.

Influences of mechanical exposure biographies on physical capabilities of workers from automotive industry - a study on possible dose-response relationships and consequences for short and long term job rotation.

PubMed

Rademacher, Holger; Bruder, Ralph; Sinn-Behrendt, Andrea; Landau, Kurt

2012-01-01

This paper describes a field study in production areas of a vehicle manufacturing plant, where 106 male workers (aged from 20 to 63 years) were examined and interviewed by the authors. Aim of study was to identify relationships between specific physical worker capabilities and doses of mechanical exposures using self-developed standardized questionnaires as well as a battery of work-specific tests. The dependent variables are different "physical capabilities", classified using a five-point rating scale with regard to the grade of limitation of the respective capability. Independent variables are "age" and specific "mechanical exposures". Several exposures were combined and multiplied with their respective durations in order to determine doses on three different body regions - back, shoulder-neck and upper limbs. There are significant positive correlations between "age" and "dose of mechanical exposure on back/shoulder-neck/upper limbs region". The analysis of the relationship between dose of exposure and different capabilities to lift or reposition loads (with variable weight) shows weak significant correlations for all three body regions. Data analysis shows no significant correlations between any dose of mechanical exposure and capabilities to work in awkward body postures.These results should be considered in age management programs when scheduling future employee assignments to workplaces, especially for production systems where manual handling tasks are dominant.

The influence of low-frequency magnetic field on plasma antioxidant capacity and heart rate.

PubMed

Ciejka, Elzbieta B; Goraca, Anna

2009-01-01

Low-frequency magnetic field is widely applied as magnetotherapy in physiotherapeutic treatment. Recognition of positive and negative effects of the magnetic field has been the subject of numerous studies. Experimental studies concern, among others, the effect of this field on the heart rate and plasma antioxidant capacity. The aim of the study was to check whether a time-variable magnetic field of constant frequency and induction affects the heart rate and plasma antioxidant capacity. The tests were performed on Spraque-Dawley rats exposed to the magnetic field of the following parameters: frequency - 40 Hz, induction - 7 mT, time of exposure - 30 and 60 minutes. The measurements of ECG and plasma antioxidant capacity expressed in the number of reduced iron ions were performed on experimental animals: before, after a single exposure and after 14 days of exposure. A significant decrease of the heart rate was observed after 14 days of exposure. A variable magnetic field of the parameters: frequency - 40 Hz, induction - 7 mT and exposure time of 14 days caused an increase of the organism antioxidant defence, whereas a variable magnetic field of the frequency of 40 Hz, induction - 7 mT and exposure time 60 minutes for 14 days caused a significant decrease of the organism antioxidant defence. The exposure time affects heart rate, plasma antioxidant capacity and the organism defense ability against free radicals.

Effects of antipsychotic drugs on cardiovascular variability in participants with bipolar disorder

PubMed Central

Linder, Jonathan R.; Sodhi, Simrit K.; Haynes, William G.; Fiedorowicz, Jess G.

2014-01-01

Objective The risk for cardiovascular diseases is elevated in persons with bipolar disorder. However, it remains unknown how much of this excess risk is secondary to pharmacologic treatment. We tested the hypothesis that current and cumulative antipsychotic drug exposure is associated with increased cardiovascular risk as indicated by lower heart rate variability (HRV) and increased blood pressure variability (BPV). Methods 55 individuals with bipolar disorder (33±7 years; 67% female) underwent non-invasive electrocardiogram assessment of time- and frequency-domain HRV, as well as BPV analysis. Medication histories were obtained through systematic review of pharmacy records for the past five years. Results Current antipsychotic exposure was associated with lower SDNN. Second generation antipsychotics were associated with lower SDNN and RMSSD. There was no significant relationship between five-year antipsychotic exposure and HRV in subjects with bipolar disorder. Exploratory analysis revealed a possible link between SSRI exposure and increased low frequency spectral HRV. Conclusions Current antipsychotic use (particularly second generation antipsychotics with high affinities for the D2S receptor) is associated with reduced autonomic-mediated variability of heart rate. The absence of an association with cumulative exposure suggests that the effects are acute in onset, and may therefore relate more to altered autonomic function than structural cardiovascular abnormalities. Future studies should prospectively examine effects of these antipsychotics on autonomic function. PMID:24590543

Occupational exposures and changes in pulmonary function over 13 years among residents of Cracow.

PubMed Central

Krzyzanowski, M; Jedrychowski, W; Wysocki, M

1988-01-01

In a 13 year follow up study conducted among residents of Cracow the relation of annual rate of decline in FEV1 to occupational exposures was analysed. The study group consisted of 696 men and 983 women aged 19-60 at the start of the study in 1968. They were interviewed three times, in 1968, 1973, and 1981, and decline in FEV1 was estimated for each subject from spirometric measurements in 1968 and 1981. The interviews provided data on exposure at the workplace to dusts, variable temperature, and chemicals or irritating gases, which established duration and time of the exposure. The FEV1 mean level, height, and smoking habits were considered as confounders in the analysis. The study indicated that the most pronounced influence on decline in FEV1 was prolonged and continuing exposure to variable temperature. The effects of dusts, independent of exposure to variable temperature, were much smaller but analysis in occupational subgroups suggest that dust may be important in some, such as workers in the building materials and pottery industry. Relatively immediate effects of exposure to chemicals were detected independently of effects of other exposures. The estimated effects of occupational exposures were of a similar magnitude as those of tobacco smoking though related to much smaller groups. Both effects were additive in accelerating decline in lung function. These results, obtained in the general population and less biased by selection than studies performed in industrial settings, show the importance of occupational factors in the natural history of limitation of airflow. PMID:3203079

Sobol' sensitivity analysis for stressor impacts on honeybee ...

EPA Pesticide Factsheets

We employ Monte Carlo simulation and nonlinear sensitivity analysis techniques to describe the dynamics of a bee exposure model, VarroaPop. Daily simulations are performed of hive population trajectories, taking into account queen strength, foraging success, mite impacts, weather, colony resources, population structure, and other important variables. This allows us to test the effects of defined pesticide exposure scenarios versus controlled simulations that lack pesticide exposure. The daily resolution of the model also allows us to conditionally identify sensitivity metrics. We use the variancebased global decomposition sensitivity analysis method, Sobol’, to assess firstand secondorder parameter sensitivities within VarroaPop, allowing us to determine how variance in the output is attributed to each of the input variables across different exposure scenarios. Simulations with VarroaPop indicate queen strength, forager life span and pesticide toxicity parameters are consistent, critical inputs for colony dynamics. Further analysis also reveals that the relative importance of these parameters fluctuates throughout the simulation period according to the status of other inputs. Our preliminary results show that model variability is conditional and can be attributed to different parameters depending on different timescales. By using sensitivity analysis to assess model output and variability, calibrations of simulation models can be better informed to yield more

Adapting to variable prismatic displacement

NASA Technical Reports Server (NTRS)

Welch, Robert B.; Cohen, Malcolm M.

1989-01-01

In each of two studies, subjects were exposed to a continuously changing prismatic displacement with a mean value of 19 prism diopters (variable displacement) and to a fixed 19-diopter displacement (fixed displacement). In Experiment 1, significant adaptation (post-pre shifts in hand-eye coordination) was found for fixed, but not for variable, displacement. Experiment 2 demonstrated that adaptation was obtained for variable displacement, but it was very fragile and is lost if the measures of adaptation are preceded by even a very brief exposure of the hand to normal or near-normal vision. Contrary to the results of some previous studies, an increase in within-S dispersion was not found of target pointing responses as a result of exposure to variable displacement.

Use of Markov Chain Monte Carlo analysis with a physiologically-based pharmacokinetic model of methylmercury to estimate exposures in US women of childbearing age.

PubMed

Allen, Bruce C; Hack, C Eric; Clewell, Harvey J

2007-08-01

A Bayesian approach, implemented using Markov Chain Monte Carlo (MCMC) analysis, was applied with a physiologically-based pharmacokinetic (PBPK) model of methylmercury (MeHg) to evaluate the variability of MeHg exposure in women of childbearing age in the U.S. population. The analysis made use of the newly available National Health and Nutrition Survey (NHANES) blood and hair mercury concentration data for women of age 16-49 years (sample size, 1,582). Bayesian analysis was performed to estimate the population variability in MeHg exposure (daily ingestion rate) implied by the variation in blood and hair concentrations of mercury in the NHANES database. The measured variability in the NHANES blood and hair data represents the result of a process that includes interindividual variation in exposure to MeHg and interindividual variation in the pharmacokinetics (distribution, clearance) of MeHg. The PBPK model includes a number of pharmacokinetic parameters (e.g., tissue volumes, partition coefficients, rate constants for metabolism and elimination) that can vary from individual to individual within the subpopulation of interest. Using MCMC analysis, it was possible to combine prior distributions of the PBPK model parameters with the NHANES blood and hair data, as well as with kinetic data from controlled human exposures to MeHg, to derive posterior distributions that refine the estimates of both the population exposure distribution and the pharmacokinetic parameters. In general, based on the populations surveyed by NHANES, the results of the MCMC analysis indicate that a small fraction, less than 1%, of the U.S. population of women of childbearing age may have mercury exposures greater than the EPA RfD for MeHg of 0.1 microg/kg/day, and that there are few, if any, exposures greater than the ATSDR MRL of 0.3 microg/kg/day. The analysis also indicates that typical exposures may be greater than previously estimated from food consumption surveys, but that the variability in exposure within the population of U.S. women of childbearing age may be less than previously assumed.

Exposure to cannabis in popular music and cannabis use among adolescents.

PubMed

Primack, Brian A; Douglas, Erika L; Kraemer, Kevin L

2010-03-01

Cannabis use is referenced frequently in American popular music, yet it remains uncertain whether exposure to these references is associated with actual cannabis use. We aimed to determine if exposure to cannabis in popular music is associated independently with current cannabis use in a cohort of urban adolescents. We surveyed all 9th grade students at three large US urban high schools. We estimated participants' exposure to lyrics referent to cannabis with overall music exposure and content analyses of their favorite artists' songs. Outcomes included current (past 30 days) and ever use of cannabis. We used multivariable regression to assess independent associations between exposures and outcomes while controlling for important covariates. Each of the 959 participants was exposed to an estimated 27 cannabis references per day [correction added on 19 January 2010, after first online publication: 40 has been changed to 27] (standard deviation = 73 [correction added on 19 January 2010, after first online publication: 104 has been changed to 73]). Twelve per cent (n = 108) were current cannabis users and 32% (n = 286) had ever used cannabis. Compared with those in the lowest tertile of total cannabis exposure in music, those in the highest tertile of exposure were almost twice as likely to have used cannabis in the past 30 days (odds ratio = 1.83; 95% confidence interval = 1.04, 3.22), even after adjusting for socio-demographic variables, personality characteristics and parenting style. As expected, however, there was no significant relationship between our cannabis exposure variable and a sham outcome variable of alcohol use. This study supports an independent association between exposure to cannabis in popular music and early cannabis use among urban American adolescents.

Association between unemployment, income, education level, population size and air pollution in Czech cities: evidence for environmental inequality? A pilot national scale analysis.

PubMed

Branis, Martin; Linhartova, Martina

2012-09-01

We analyzed differentials in exposure to SO(2), PM(10) and NO(2) among Czech urban populations categorized according to education level, unemployment rate, population size and average annual salary. Altogether 39 cities were included in the analysis. The principal component analysis revealed two factors explaining 72.8% of the data variability. The first factor explaining 44.7% of the data variability included SO(2), PM(10), low education level and high unemployment, documenting that inhabitants with unfavorable socioeconomic status mainly reside in smaller cities with higher concentration levels of combustion-related air pollutants. The second factor explaining 28.1% of the data variability included NO(2), high salary, high education level and large population, suggesting that large cities with residents with higher socioeconomic status are exposed to higher levels of traffic-related air pollution. We conclude that, after more than a decade of free-market economy, the Czech Republic, a former Soviet satellite with a centrally planned economy, displays signs of a certain kind of environmental inequality, since environmental hazards are unevenly distributed among the Czech urban populations. Copyright © 2012 Elsevier Ltd. All rights reserved.

Contamination and radiation exposure in central Europe after the Chernobyl accident

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

Bayer, A.; Mueck, K.; Loosli, H.H.

1996-06-01

Ten years ago, on 26 April 1986, as a consequence of an accident in Unit 4 of the Chernobyl-NPP, a large quantity of radioactive material was released into the atmosphere for some days. This material was spread over wide areas of Europe. Due to variable weather conditions the activity concentrations in air varied considerably in different regions. Also as a consequence of large variations in precipitation intensity-particularly in the regions of Southeastern Germany, Austria and Southern Switzerland-up to 100 kBq m{sup -2} {sup 137}Cs were deposited on the soil. Due to fallout, washout, and/or rainout, a range of foodstuffs weremore » contaminated, and foodstuffs directly exposed to the fallout [vegetables and green fodder (grass)] showed the highest contamination levels. Consequently, milk also showed a significantly increased activity concentration, in particular of {sup 131}I. In the following years contamination in all kinds of foodstuffs decreased, but elevated contamination levels in special pathways like venison and mushrooms are still observed to date. This contamination resulted in additional exposure, mainly due to external radiation from ground and from consumption of contaminated food. The radiation exposure in the most contaminated areas was calculated on the basis of model assumptions and was found to be about 1 mSv during the first year after the accident. Using this model, the ingestion pathway was overestimated by at least a factor of two. This additional exposure decreased and is now less than 1 % on average; in the most contaminated areas, this is a few percent of the average natural radiation exposure.« less

Individual exposure estimates may be erroneous when spatiotemporal variability of air pollution and human mobility are ignored.

PubMed

Park, Yoo Min; Kwan, Mei-Po

2017-01-01

This study aims to empirically demonstrate the necessity to consider both the spatiotemporal variability of air pollution and individual daily movement patterns in exposure and health risk assessment. It compares four different types of exposure estimates generated by using (1) individual movement data and hourly air pollution concentrations; (2) individual movement data and daily average air pollution data; (3) residential location and hourly pollution levels; and (4) residential location and daily average pollution data. These four estimates are significantly different, which supports the argument that ignoring the spatiotemporal variability of environmental risk factors and human mobility may lead to misleading results in exposure assessment. Additionally, three-dimensional (3D) geovisualization presented in the paper shows how person-specific space-time context is generated by the interactions between air pollution and an individual, and how the different individualized contexts place individuals at different levels of health risk. Copyright © 2016 Elsevier Ltd. All rights reserved.

Racial/Ethnic and Socio-Contextual Correlates of Chronic Sleep Curtailment in Childhood

PubMed Central

Peña, Michelle-Marie; Rifas-Shiman, Sheryl L.; Gillman, Matthew W.; Redline, Susan; Taveras, Elsie M.

2016-01-01

Study Objectives: To examine the association between race/ethnicity and sleep curtailment from infancy to mid-childhood, and to determine the extent to which socioeconomic and contextual factors both explain racial/ethnic differences and are independently associated with sleep curtailment. Methods: We studied 1,288 children longitudinally in Project Viva, a pre-birth cohort study, from 6 months to 7 years of age. The main exposure was the child's race/ethnicity. The main outcome was a sleep curtailment score from 6 months to 7 years. The score ranged from 0–13, where 0 indicated maximal sleep curtailment and 13 indicated never having curtailed sleep. Results: The mean (standard deviation) sleep curtailment score was 10.2 (2.7) points. In adjusted models (β [95% CI]), black (−1.92, [−2.39, −1.45] points), Hispanic (−1.58, [−2.43, −0.72] points), and Asian (−1.71, [−2.55, −0.86] points) children had lower sleep scores than white children. Adjustment for sociodemographic covariates attenuated racial/ethnic differences in sleep scores for black (by 24%) and Hispanic children (by 32%) but strengthened the differences for Asian children by 14%. Further adjustment for environmental and behavioral variables did not substantially change these differences. Independently, low maternal education, living in households with incomes < $70,000, viewing more TV, and having a TV in the child's bedroom were associated with lower sleep scores. Conclusions: Chronic sleep curtailment from infancy to mid-childhood was more prevalent among black, Hispanic, and Asian children. These differences were partially but not entirely explained by socio-contextual variables. Independently, children from lower socioeconomic status and those with greater exposures to TV also had greater sleep curtailment. Citation: Peña MM, Rifas-Shiman SL, Gillman MW, Redline S, Taveras EM. Racial/ethnic and socio-contextual correlates of chronic sleep curtailment in childhood. SLEEP 2016;39(9):1653–1661. PMID:27306269

Seasonal changes in environmental variables, biomass, production and nutrient contents in two contrasting tropical intertidal seagrass beds in South Sulawesi, Indonesia.

PubMed

Erftemeijer, Paul L A; Herman, Peter M J

1994-09-01

Seasonal dynamics were studied by monthly monitoring of biological and environmental variables in permanent quadrats in two contrasting intertidal seagrass beds in South Sulawesi, Indonesia, from February 1991 to January 1992. Datasets were analysed with canonical correlation analysis for correlations between environmental and biological variables. Considerable variation in biomass, production and plant tissue nutrient contents in a monospecific seagrass bed of Enhalus acoroides, growing on a coastal terrigenous mudbank (Gusung Tallang), was assumed to be related to riverine influences of the nearby Tallo River. The variation in seagrass variables at this site could, however, not be significantly correlated to seasonal patterns in rainfall, salinity, tides, nutrient availability, water motion or turbidity. A seasonal cycle in biomass, production and nutrient contents in a mixed seagrass bed of Thalassia hemprichii and E. acoroides, growing on carbonate sand on the reef flat of an offshore coral island (Barang Lompo), was found to be largely determined by tidal exposure and water motion. Exposure of the intertidal seagrass bed during hours of low water during spring tides showed a gradual shift from exposure during the night (January-June) to exposure during daylight (July-December). Daylight exposure resulted in a significant loss of above-ground plant biomass through desiccation and 'burning' of leaves. The observed seasonal dynamics of the seagrass bed on reef sediment contrast with reports from the Caribbean, where the effect of tidal exposure on comparable shallow-water seagrass communities is relatively insignificant due to a small tidal amplitude.

Personality and long term exposure to organic solvents

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

Lindstroem, K.; Martelin, T.

1980-01-01

Personality, especially emotional reactions of two solvent exposed groups and a nonexposed reference group were described by means of 20 formal, content and check-list type of Rorschach variables. Another objective of the study was to explore the suitability and psychological meaning of other types of Rorschach variables than those applied earlier in the field of behavioral toxicology. The factor analyses grouped the applied variables into factors of Productivity, Ego Strength, Control of Emotionality, Defensive Introversion and Aggressiveness. One solvent group, a patient groups (N.53), was characterized by a high number of Organic signs and a low Genetic Level, indicating possiblemore » psychoorganic deterioration. The other solvent group, styrene exposed but subjectively healthy (N.98), was characterized by few emotional reactions, low Anxiety and a low number of Neurotic Signs. the long duration of exposure of the solvent patient group (mean 10.2 +/- 8.7 years) was related to variables of the Productivity factor, a finding that indicates a possible better adjustment of those exposed for a longer time. The duration of exposure of the styrene exposed group (mean 4.9 +/- 3.2 years) revealed a very slight relation to personality variables, but the mean urinary mandelic acid concentration, indicating the level of styrene exposure, correlated with increased emotional reactions. For the most part definite causal conclusions could not be drawn because of the cross-sectional design of the study.« less

Suicidal ideation among adolescents following natural disaster: The role of prior interpersonal violence.

PubMed

Zuromski, Kelly L; Resnick, Heidi; Price, Matthew; Galea, Sandro; Kilpatrick, Dean G; Ruggiero, Kenneth

2018-05-07

The current study examined variables, including prior traumatic events, disaster exposure, and current mental health symptomatology, associated with suicidal ideation following experience of a natural disaster. Utilizing a sample of 2,000 adolescents exposed to the spring 2011 tornadoes in the areas surrounding Tuscaloosa, Alabama, and Joplin, Missouri, we hypothesized that prior interpersonal violence (IPV), more so than other prior traumatic events or other symptoms, would be associated with suicidal ideation after the disaster. Suicidal ideation was reported by approximately 5% of the sample. Results of binary logistic regression were consistent with hypotheses in that prior IPV exposure emerged as the variable most robustly related to presence of postdisaster suicidal ideation, even accounting for current symptoms (i.e., posttraumatic stress disorder and depression). Moreover, neither prior accident nor prior natural disaster exposure was significantly associated with postdisaster suicidal ideation, suggesting that something specific to IPV may be conferring risk for suicidality. No other variables, including disaster exposure variables or demographic characteristics, emerged as significantly related. Our results suggest that individuals who have a history of IPV may be particularly vulnerable following experience of additional traumatic events and that for suicide risk, the experience of prior IPV may be more relevant to consider in the aftermath of natural disasters beyond variables related to the index trauma or current symptomatology. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Hierarchical Synthesis of Coastal Ecosystem Health Indicators at Karimunjawa National Marine Park

NASA Astrophysics Data System (ADS)

Danu Prasetya, Johan; Ambariyanto; Supriharyono; Purwanti, Frida

2018-02-01

The coastal ecosystem of Karimunjawa National Marine Park (KNMP) is facing various pressures, including from human activity. Monitoring the health condition of coastal ecosystems periodically is needed as an evaluation of the ecosystem condition. Systematic and consistent indicators are needed in monitoring of coastal ecosystem health. This paper presents hierarchical synthesis of coastal ecosystem health indicators using Analytic Hierarchy Process (AHP) method. Hierarchical synthesis is obtained from process of weighting by paired comparison based on expert judgments. The variables of coastal ecosystem health indicators in this synthesis consist of 3 level of variable, i.e. main variable, sub-variable and operational variable. As a result of assessment, coastal ecosystem health indicators consist of 3 main variables, i.e. State of Ecosystem, Pressure and Management. Main variables State of Ecosystem and Management obtain the same value i.e. 0.400, while Pressure value was 0.200. Each main variable consist of several sub-variable, i.e. coral reef, reef fish, mangrove and seagrass for State of Ecosystem; fisheries and marine tourism activity for Pressure; planning and regulation, institutional and also infrastructure and financing for Management. The highest value of sub-variable of main variable State of Ecosystem, Pressure and Management were coral reef (0.186); marine tourism pressure (0.133) and institutional (0.171), respectively. The highest value of operational variable of main variable State of Ecosystem, Pressure and Management were percent of coral cover (0.058), marine tourism pressure (0.133) and presence of zonation plan, regulation also socialization of monitoring program (0.53), respectively. Potential pressure from marine tourism activity is the variable that most affect the health of the ecosystem. The results of this research suggest that there is a need to develop stronger conservation strategies to facing with pressures from marine tourism activities.

Comparison of human exposure model estimates of PM2.5 exposure variability using fine-scale CMAQ simulations from the Baltimore DISCOVER-AQ evaluation

EPA Science Inventory

Human exposure models estimate population distributions of exposure to air pollutants by combining ambient (outdoor) concentration data with human activity patterns to account for the time people spend in different locations (e.g., outdoors, indoors, in vehicles) and the various ...

Poison exposures in young Israeli military personnel: a National Poison Center Data analysis.

PubMed

Lavon, Ophir; Bentur, Yedidia

2017-06-01

To characterize poison exposures in young Israeli military personnel as reported to the national poison center. Retrospective poison center chart review over a 14-year period. Cases included were Israeli soldiers aged 18-21 years, the compulsory military service age required by the Israeli law. 1770 records of poison exposures in young military personnel were identified. Most exposed individuals involved males (n = 1268, 71.6%). Main routes of exposure were ingestion (n = 854, 48.3%), inhalation (n = 328, 18.6%) and ocular (n = 211, 11.9%). Accidents or misuse (n = 712, 40.2%) were the most frequently reported circumstances, followed by suicide attempts (370, 20.9%), and bites and stings (161, 9.1%). More than half of the cases involved chemicals (n = 939, 53.1%); hydrocarbons, gases and corrosives were the main causative agents. Pharmaceuticals (mainly analgesics) were involved in 519 (29.3%) cases, venomous animals (mainly scorpions, centipedes, and snakes) in 79 (4.5%). Clinical manifestations were reported in 666 (37.6%) cases, mostly gastrointestinal, neurologic, and respiratory. The vast majority of cases (1634, 92.3%) were asymptomatic or mildly affected; no fatalities were recorded. In 831 (46.9%) cases the clinical toxicologist recommended referral to an emergency department; ambulatory observation was recommended in 563 (31.8%) cases, and hospitalization in 86 (4.9%). Our data show that poison exposures among young soldiers involve mainly males, accidents, misuse and suicides, oral route and chemicals; most exposures were asymptomatic or with mild severity. Repeated evaluations of poison center data pertaining to military personnel is advised for identifying trends in poison exposure and characteristics in this particular population.

Utility of computed tomography in assessment of pulmonary hypertension secondary to biomass smoke exposure

PubMed Central

Sertogullarindan, Bunyamin; Bora, Aydin; Yavuz, Alpaslan; Ekin, Selami; Gunbatar, Hulya; Arisoy, Ahmet; Avcu, Serhat; Ozbay, Bulent

2014-01-01

Background The aim of this study was to investigate the feasibility of main pulmonary artery diameter quantification by thoracic computerized tomography (CT) in the diagnosis of pulmonary hypertension seconder to biomass smoke exposure. Material/Methods One hundred and four women subjects with biomass smoke exposure and 20 healthy women subjects were enrolled in the prospective study. The correlation between echocardiographic estimation of systolic pulmonary artery pressure and the main pulmonary artery diameter of the cases were studied. Results The main pulmonary artery diameter was 26.9±5.1 in the control subjects and 37.1±6.4 in subjects with biomass smoke exposure. This difference was statistically significant (p<0.001). The systolic pulmonary artery pressure was 22.7±12.4 in the control subjects and 57.3±22 in subjects with biomass smoke exposure. This difference was statistically significant (p<0.001). Systolic pulmonary artery pressure was significantly correlated with the main pulmonary artery diameter (r=0.614, p<0.01). A receiver operating characteristic (ROC) curve analysis showed that a value of 29 mm of the main pulmonary artery diameter differentiated between pulmonary hypertension and non-pulmonary hypertension patients. The sensitivity of the measurement to diagnose pulmonary hypertension was 91% and specificity was 80%. Conclusions Our results indicate that main pulmonary artery diameter measurements by SCT may suggest presence of pulmonary hypertension in biomass smoke exposed women. PMID:24618994

Small car exposure data project. Phase 1 : methodology

DOT National Transportation Integrated Search

1985-10-01

The Small Car Exposure Data Project represents the first phase of an effort to build a data : base of exposure variables for crash-avoidance studies. Among these are: (1) vehicle make, : model, year, body style, wheel base, weight, and horsepower; (2...

Characterizing Variability and Uncertainty in Exposure Assessments Improves links to Environmental Decision-Making

EPA Science Inventory

Environmental Decisions often rely upon observational data or model estimates. For instance, the evaluation of human health or ecological risks often includes information on pollutant emission rates, environmental concentrations, exposures, and exposure/dose-response data. Whet...

THE CONTRIBUTION OF PARTICLE RESUSPENSION TO INDOOR AND PERSONAL AIR CONCENTRATIONS

EPA Science Inventory

An association has been demonstrated between ambient PM concentrations and human morbidity/mortality. However, little is known regarding the most important sources of PM exposure, inter- and intrapersonal variability in exposure, and the relationship between personal exposure a...

Non-dietary environmental risk factors in prostate cancer

PubMed Central

Ferrís-i-Tortajada, J; Berbel-Tornero, O; Garcia-i-Castell, J; López-Andreu, J.A.; Sobrino-Najul, E; Ortega-García, J.A.

2016-01-01

Introduction The aim is to update and disclose the main environmental risk factors, excluding dietary factors, involved in the etiopathology of prostate cancer. Materials and methods Bibliographic review of the last 25 years of non-dietary environmental risk factors associated with prostate cancer between 1985 and 2010, obtained from MedLine, CancerLit, Science Citation Index and Embase. The search profiles were Environmental Risk Factors/Tobacco/Infectious-Inflammatory Factors/Pesticides/Vasectomy/Occupational Exposures/ Chemoprevention Agents/Radiation and Prostate Cancer. Results While some non-dietary environmental risk factors increase the risk of acquiring the disease, others decrease it. Of the former, it is worth mentioning exposal to tobacco smoke, chronic infectious-inflammatory prostatic processes and occupational exposure to cadmium, herbicides and pesticides. The first factors that reduce the risk are the use of chemopreventive drugs (Finasterida, Dutasteride) and exposure to ultraviolet solar radiation. With the current data, a vasectomy does not influence the risk of developing the disease. Conclusions The slow process of prostate carcinogenesis is the final result of the interaction of constitutional risk and environmental factors. Non-dietary environmental factors play an important role in the etiopathology of this disease. To appropriately assess the risk factors, extensive case studies that include all the possible variables must be analyzed. PMID:21439685

Reliability of concentrations of organophosphate pesticide metabolites in serial urine specimens from pregnancy in the Generation R Study.

PubMed

Spaan, Suzanne; Pronk, Anjoeka; Koch, Holger M; Jusko, Todd A; Jaddoe, Vincent W V; Shaw, Pamela A; Tiemeier, Henning M; Hofman, Albert; Pierik, Frank H; Longnecker, Matthew P

2015-05-01

The widespread use of organophosphate (OP) pesticides has resulted in ubiquitous exposure in humans, primarily through their diet. Exposure to OP pesticides may have adverse health effects, including neurobehavioral deficits in children. The optimal design of new studies requires data on the reliability of urinary measures of exposure. In the present study, urinary concentrations of six dialkyl phosphate (DAP) metabolites, the main urinary metabolites of OP pesticides, were determined in 120 pregnant women participating in the Generation R Study in Rotterdam. Intra-class correlation coefficients (ICCs) across serial urine specimens taken at <18, 18-25, and >25 weeks of pregnancy were determined to assess reliability. Geometric mean total DAP metabolite concentrations were 229 (GSD 2.2), 240 (GSD 2.1), and 224 (GSD 2.2) nmol/g creatinine across the three periods of gestation. Metabolite concentrations from the serial urine specimens in general correlated moderately. The ICCs for the six DAP metabolites ranged from 0.14 to 0.38 (0.30 for total DAPs), indicating weak to moderate reliability. Although the DAP metabolite levels observed in this study are slightly higher and slightly more correlated than in previous studies, the low to moderate reliability indicates a high degree of within-person variability, which presents challenges for designing well-powered epidemiological studies.

Evaluation of the Knowledge and Attitudes of Dental Students toward Occupational Blood Exposure Accidents at the End of the Dental Training Program

PubMed Central

Hbibi, Abdelhadi; Kasouati, Jalal; Charof, Reda; Chaouir, Souad; El Harti, Karima

2018-01-01

Aims and Objectives: This study was conducted to assess knowledge, attitudes, and behavior regarding occupational blood exposure accidents (OBEA) among dental students at the end of the whole dental education program. Materials and Methods: The survey was performed using a student self-administered questionnaire during July 2015 in the dental teaching hospital in Rabat. It was conducted on 117 dental students registered in the 5th year. The results were analyzed by SPSS Software, Version 13.0. Univariate analysis was performed by descriptive statistics, and bivariate analysis was used to identify correlations between different variables. Results: Eighty-three students answered the questionnaire (participation rate: 70%). Most participants had incomplete knowledge about the management and the risks of OBEA. Thirty-five participants (42%) experienced at least one occupational exposure to patients' blood. Needle recapping has been the main cause of such injuries (41%). Most accidents occurred, respectively, in the oral surgery (51%) and the restorative dentistry (17%) departments. According to many participants, they had received insufficient education concerning this topic. Conclusions: More effective education on prevention and management of OBEA is highly recommended to reduce the prevalence of such injuries. Dental schools should set up a local management unit for following and supporting the exposed students. PMID:29629333

Light Effects on Behavioural Performance Depend on the Individual State of Vigilance

PubMed Central

Barba, Antonio; Padilla, Francisca

2016-01-01

Research has shown that exposure to bright white light or blue-enriched light enhances alertness, but this effect is not consistently observed in tasks demanding high-level cognition (e.g., Sustained Attention to Response Task—SART, which measures inhibitory control). Individual differences in sensitivity to light effects might be mediated by variations in the basal level of arousal. We tested this hypothesis by measuring the participants’ behavioural state of vigilance before light exposure, through the Psychomotor Vigilance Task. Then we compared the effects of a blue-enriched vs. dim light at nighttime on the performance of the auditory SART, by controlling for individual differences in basal arousal. The results replicated the alerting effects of blue-enriched light, as indexed by lower values of both proximal temperature and distal-proximal gradient. The main finding was that lighting effects on SART performance were highly variable across individuals and depended on their prior state of vigilance. Specifically, participants with higher levels of basal vigilance before light exposure benefited most from blue-enriched lighting, responding faster in the SART. These results highlight the importance of considering basal vigilance to define the boundary conditions of light effects on cognitive performance. Our study adds to current research delineating the complex and reciprocal interactions between lighting effects, arousal, cognitive task demands and behavioural performance. PMID:27820822

Light Effects on Behavioural Performance Depend on the Individual State of Vigilance.

PubMed

Correa, Ángel; Barba, Antonio; Padilla, Francisca

2016-01-01

Research has shown that exposure to bright white light or blue-enriched light enhances alertness, but this effect is not consistently observed in tasks demanding high-level cognition (e.g., Sustained Attention to Response Task-SART, which measures inhibitory control). Individual differences in sensitivity to light effects might be mediated by variations in the basal level of arousal. We tested this hypothesis by measuring the participants' behavioural state of vigilance before light exposure, through the Psychomotor Vigilance Task. Then we compared the effects of a blue-enriched vs. dim light at nighttime on the performance of the auditory SART, by controlling for individual differences in basal arousal. The results replicated the alerting effects of blue-enriched light, as indexed by lower values of both proximal temperature and distal-proximal gradient. The main finding was that lighting effects on SART performance were highly variable across individuals and depended on their prior state of vigilance. Specifically, participants with higher levels of basal vigilance before light exposure benefited most from blue-enriched lighting, responding faster in the SART. These results highlight the importance of considering basal vigilance to define the boundary conditions of light effects on cognitive performance. Our study adds to current research delineating the complex and reciprocal interactions between lighting effects, arousal, cognitive task demands and behavioural performance.

Relevance of air conditioning for 222Radon concentration in shops of the Savona Province, Italy.

PubMed

Panatto, Donatella; Ferrari, Paola; Lai, Piero; Gallelli, Giovanni

2006-02-15

Radon (222Rn) concentration was evaluated in shops of the Savona Province, Italy, between summer 2002 and winter 2002-2003. The main characteristics of each shops were recorded through a questionnaire investigating the ventilation rate and factors related to 222Rn precursors in the soil and the construction materials. The main variables that were related to radon concentration were the following: age of the building, level of the shop above ground, season of the year, wind exposure, active windows, and type of heating system. Shops equipped with individual air heating/conditioning systems exhibited radon concentrations that were three times higher than those of shops heated by centralized furnaces. Our data indicate that the level of pollution in the shops was of medium level, with an expected low impact on the salespersons' health. Only in wintertime, the action level of 200 Bq m(-3) for the confined environment was reached in 10 shops equipped with individual air heating/conditioning systems.

Complexity of food preparation and food security status in low-income young women.

PubMed

Engler-Stringer, Rachel; Stringer, Bernadette; Haines, Ted

2011-01-01

This study was conducted to explore whether preparing more complex meals was associated with higher food security status. This mixed-methods, community-based study involved the use of semistructured interviews to examine the cooking practices of a group of young, low-income women in Montreal. Fifty participants aged 18 to 35 were recruited at 10 locations in five low-income neighbourhoods. Food security status was the main outcome measure and the main exposure variable, "complex food preparation," combined the preparation of three specific food types (soups, sauces, and baked goods) using basic ingredients. Low-income women preparing a variety of meals using basic ingredients at least three times a week were more than twice as likely to be food secure as were women preparing more complex meals less frequently. Women who prepared more complex meals more frequently had higher food security. Whether this means that preparing more complex foods results in greater food security remains unclear, as this was an exploratory study.

Long-Term Coarse Particulate Matter Exposure and Heart Rate Variability in the Multi-Ethnic Study of Atherosclerosis (MESA)

PubMed Central

Adhikari, Richa; D’Souza, Jennifer; Solimon, Elsayed Z.; Burke, Gregory L.; Daviglus, Martha; Jacobs, David R.; Park, Sung Kyun; Sheppard, Lianne; Thorne, Peter S.; Kaufman, Joel D.; Larson, Timothy V.; Adar, Sara D.

2017-01-01

Background Reduced heart rate variability, a marker of impaired cardiac autonomic function, has been linked to short-term exposure to airborne particles. This research adds to the literature by examining associations with long-term exposures to coarse particles (PM10-2.5). Methods Using electrocardiogram recordings from 2,780 participants (45-84 years) from three Multi-Ethnic Study of Atherosclerosis sites, we assessed the standard deviation of normal-to-normal intervals (SDNN) and root-mean square differences of successive normal-to-normal intervals (rMSSD) at a baseline (2000-2002) and follow-up (2010-2012) examination (mean visits/person=1.5). Annual average concentrations of PM10-2.5 mass, copper, zinc, phosphorus, silicon, and endotoxin were estimated using site-specific spatial prediction models. We assessed associations for baseline heart rate variability and rate of change in heart rate variability over time using multivariable mixed models adjusted for time, sociodemographic, lifestyle, health, and neighborhood confounders, including co-pollutants. Results In our primary models adjusted for demographic and lifestyle factors and site, PM10-2.5 mass was associated with 1.0% (95% CI: -4.1, 2.1%) lower SDNN levels per interquartile range of 2 μg/m3. Stronger associations, however, were observed prior to site adjustment and with increasing residential stablity. Similar patterns were found for rMSSD. We found little evidence for associations with other chemical species and with with the rate of change in heart rate variability, though endotoxin was associated with increasing heart rate variability over time. Conclusion We found only weak evidence that long-term PM10-2.5 exposures are associated with lowered heart rate variability. Stronger associations among residentially stable individuals suggest that confirmatory studies are needed. PMID:27035690

Accounting for neutron exposure in the Japanese atomic bomb survivors.

PubMed

Cullings, Harry M; Pierce, Donald A; Kellerer, Albrecht M

2014-12-01

The Japanese atomic bomb survivors that were directly exposed to both γ rays and neutrons have been followed by the Radiation Effects Research Foundation (RERF). The estimation of the γ-ray risks requires some adjustment for the greater biological effect of the neutrons per unit dose. Because the small neutron doses and the predominant γ-ray doses are highly correlated, the neutron relative biological effectiveness (RBE) cannot be reliably estimated from the survivors' data and information from radiobiology must be invoked. As data became available on neutron doses, RERF has used a constant neutron RBE value of 10, even though radiobiological studies indicate that the RBE values appear to have considerably larger values at low doses. The approximation RBE = 10 assumes that if the RBE is variable it takes roughly this value in the range of total dose most relevant for linear risk estimation, namely about 1 Gy. We consider some possible RBE functions to explain the correct use and the impact of a dose-dependent RBE. However, we do not advocate any particular choice or even that a variable RBE be employed. Rather we show that the assumed neutron RBE, within a wide range of choices, is far less important to the outcome of risk assessment of the RERF data than generally believed. Some of these misperceptions have been related to the consideration of variable RBE functions, and without due attention to the fact that in the case of the A-bomb survivors' data, the mixed field of neutrons and γ rays must be considered. Therefore, the RBE value of neutrons is much lower than the RBE in pure neutron fields that are used in radiobiological experiments. Thus, applying the pure neutron field RBE to the mixed-field A-bomb radiation can lead to an overestimation of the actual neutron RBE for moderate total dose levels of 1 Gy by a factor of more than four. While in a pure neutron exposure the RBE depends on the neutron dose, in the mixed field it depends on both components of exposure, and in particular, we show that in the RERF setting the RBE depends mainly on the accompanying γ-ray dose.

Development of a method to rate the primary safety of vehicles using linked New Zealand crash and vehicle licensing data.

PubMed

Keall, Michael D; Newstead, Stuart

2016-01-01

Vehicle safety rating systems aim firstly to inform consumers about safe vehicle choices and, secondly, to encourage vehicle manufacturers to aspire to safer levels of vehicle performance. Primary rating systems (that measure the ability of a vehicle to assist the driver in avoiding crashes) have not been developed for a variety of reasons, mainly associated with the difficult task of disassociating driver behavior and vehicle exposure characteristics from the estimation of crash involvement risk specific to a given vehicle. The aim of the current study was to explore different approaches to primary safety estimation, identifying which approaches (if any) may be most valid and most practical, given typical data that may be available for producing ratings. Data analyzed consisted of crash data and motor vehicle registration data for the period 2003 to 2012: 21,643,864 observations (representing vehicle-years) and 135,578 crashed vehicles. Various logistic models were tested as a means to estimate primary safety: Conditional models (conditioning on the vehicle owner over all vehicles owned); full models not conditioned on the owner, with all available owner and vehicle data; reduced models with few variables; induced exposure models; and models that synthesised elements from the latter two models. It was found that excluding young drivers (aged 25 and under) from all primary safety estimates attenuated some high risks estimated for make/model combinations favored by young people. The conditional model had clear biases that made it unsuitable. Estimates from a reduced model based just on crash rates per year (but including an owner location variable) produced estimates that were generally similar to the full model, although there was more spread in the estimates. The best replication of the full model estimates was generated by a synthesis of the reduced model and an induced exposure model. This study compared approaches to estimating primary safety that could mimic an analysis based on a very rich data set, using variables that are commonly available when registered fleet data are linked to crash data. This exploratory study has highlighted promising avenues for developing primary safety rating systems for vehicle makes and models.

Head Exposure to Cold during Whole-Body Cryostimulation: Influence on Thermal Response and Autonomic Modulation.

PubMed

Louis, Julien; Schaal, Karine; Bieuzen, François; Le Meur, Yann; Filliard, Jean-Robert; Volondat, Marielle; Brisswalter, Jeanick; Hausswirth, Christophe

2015-01-01

Recent research on whole-body cryotherapy has hypothesized a major responsibility of head cooling in the physiological changes classically reported after a cryostimulation session. The aim of this experiment was to verify this hypothesis by studying the influence of exposing the head to cold during whole-body cryostimulation sessions, on the thermal response and the autonomic nervous system (ANS). Over five consecutive days, two groups of 10 participants performed one whole-body cryostimulation session daily, in one of two different systems; one exposing the whole-body to cold (whole-body cryostimulation, WBC), and the other exposing the whole-body except the head (partial-body cryostimulation, PBC).10 participants constituted a control group (CON) not receiving any cryostimulation. In order to isolate the head-cooling effect on recorded variables, it was ensured that the WBC and PBC systems induced the same decrease in skin temperature for all body regions (mean decrease over the 5 exposures: -8.6°C ± 1.3°C and -8.3 ± 0.7°C for WBC and PBC, respectively), which persisted up to 20-min after the sessions (P20). The WBC sessions caused an almost certain decrease in tympanic temperature from Pre to P20 (-0.28 ± 0.11°C), while it only decreased at P20 (-0.14 ± 0.05°C) after PBC sessions. Heart rate almost certainly decreased after PBC (-8.6%) and WBC (-12.3%) sessions. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely to almost certainly increased after PBC (RMSSD:+49.1%, HF: +123.3%) and WBC (RMSSD: +38.8%, HF:+70.3%). Plasma norepinephrine concentration was likely increased in similar proportions after PBC and WBC, but only after the first session. Both cryostimulation techniques stimulated the ANS with a predominance of parasympathetic tone activation from the first to the fifth session and in slightly greater proportion with WBC than PBC. The main result of this study indicates that the head exposure to cold during whole-body cryostimulation may not be the main factor responsible for the effects of cryostimulation on the ANS.

Head Exposure to Cold during Whole-Body Cryostimulation: Influence on Thermal Response and Autonomic Modulation

PubMed Central

Louis, Julien; Schaal, Karine; Bieuzen, François; Le Meur, Yann; Filliard, Jean-Robert; Volondat, Marielle; Brisswalter, Jeanick; Hausswirth, Christophe

2015-01-01

Recent research on whole-body cryotherapy has hypothesized a major responsibility of head cooling in the physiological changes classically reported after a cryostimulation session. The aim of this experiment was to verify this hypothesis by studying the influence of exposing the head to cold during whole-body cryostimulation sessions, on the thermal response and the autonomic nervous system (ANS). Over five consecutive days, two groups of 10 participants performed one whole-body cryostimulation session daily, in one of two different systems; one exposing the whole-body to cold (whole-body cryostimulation, WBC), and the other exposing the whole-body except the head (partial-body cryostimulation, PBC).10 participants constituted a control group (CON) not receiving any cryostimulation. In order to isolate the head-cooling effect on recorded variables, it was ensured that the WBC and PBC systems induced the same decrease in skin temperature for all body regions (mean decrease over the 5 exposures: -8.6°C±1.3°C and -8.3±0.7°C for WBC and PBC, respectively), which persisted up to 20-min after the sessions (P20). The WBC sessions caused an almost certain decrease in tympanic temperature from Pre to P20 (-0.28 ±0.11°C), while it only decreased at P20 (-0.14±0.05°C) after PBC sessions. Heart rate almost certainly decreased after PBC (-8.6%) and WBC (-12.3%) sessions. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely to almost certainly increased after PBC (RMSSD:+49.1%, HF: +123.3%) and WBC (RMSSD: +38.8%, HF:+70.3%). Plasma norepinephrine concentration was likely increased in similar proportions after PBC and WBC, but only after the first session. Both cryostimulation techniques stimulated the ANS with a predominance of parasympathetic tone activation from the first to the fifth session and in slightly greater proportion with WBC than PBC. The main result of this study indicates that the head exposure to cold during whole-body cryostimulation may not be the main factor responsible for the effects of cryostimulation on the ANS. PMID:25915642

[Health hazards resulting from exposure to zinc and its inorganic compounds in industry].

PubMed

Pakulska, Daria; Czerczak, Sławomir

2017-10-17

This article deals with health risks resulting from exposure to zinc and its inorganic compounds in industry. The main source of zinc exposure are fumes generated during thermal and chemical processes, mainly zinc oxide fume formed by immediate oxidation of metallic zinc vapor formed during high-temperature processes, as well as dust generated during the mechanical processing of zinc-containing materials. It is recognized that zinc ions are responsible for health effects of exposure to dust/fumes of the majority of zinc compounds, and the final effect of exposure depends on the degree of dispersion of dusts/fumes suspended in the air. Since the effects of exposure depends on the particle size, occupational exposure limits have began to be established separately for respirable and inhalable fractions. A critical effect of acute exposure to respirable fraction is a "fume fever" which in chronic exposure occurs as an effect associated with recurrent symptoms of acute poisoning. Impaired lung function and asthma symptoms are considered to be the main effects of exposure to inhalable fraction. Due to the limited number of the available data it is not possible to assess carcinogenicity, reproductive toxicity and teratogenicity of zinc and its compounds. The aim of the study was to analyze the major health hazards resulting from occupational exposure to zinc and its inorganic compounds in the context of their physico-chemical properties, a wide range of applications and occupational exposure data. Med Pr 2017;68(6):779-794. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Contextual variables associated with psychosocial adjustment of adolescents.

PubMed

Sbicigo, Juliana Burges; Dell'Aglio, Débora Dalbosco

2013-01-01

This study investigated associations of contextual variables of risk (stressful events and exposure to community violence), variables of protection (family environment, connectivity to the school and community perceptions) and demographic variables (gender and age) with indicators of psychosocial adjustment (self-esteem, involvement in illegal activities and alcohol use in past month) among adolescents. The participants were 685 students (61.5% girls) aged between 12 and 18 years (M = 15.10, SD = 1.52) of public schools in southern Brazil. They answered a questionnaire with 77 questions and an inventory for assessment of family relationships. Logistic regression analyses indicated that the negative perception of family environment, poor connectivity to the school and exposure to community violence were associated with low self-esteem. Involvement in illegal activities was associated with low connectivity to school, stressful events, exposure to community violence and male sex. Finally, alcohol use/month was associated with negative perception of the community, community violence, stressful events, and particularly at the ages of 15-16 years.

Temporal and spatial variability in the estrogenicity of a municipal wastewater effluent.

PubMed

Hemming, Jon M; Allen, H Joel; Thuesen, Kevin A; Turner, Philip K; Waller, William T; Lazorchak, James M; Lattier, David; Chow, Marjorie; Denslow, Nancy; Venables, Barney

2004-03-01

The estrogenicity of a municipal wastewater effluent was monitored using the vitellogenin biomarker in adult male fathead minnows (Pimephales promelas). The variability in the expression of vitellogenin was evident among the monitoring periods. Significant (alpha< or =0.05) increases in plasma vitellogenin concentrations were detected in March and December, but not in August or June. Additionally, the magnitude of expression was variable. Variability in the spatial scale was also evident during the March and June exposure months. Concurrent exposures in both the creek receiving the effluent from a wastewater treatment plant and an experimental wetland showed estrogenicity to be different with distance from the respective effluent inflow sites. March exposures showed estrogenicity to be somewhat persistent in the receiving creek (>600 m), but to decrease rapidly within the experimental wetland (<40 m). Results are discussed relative to the monitoring season, to the spatial distribution of the response in both receiving systems, and to possible causative factors contributing to the effluent estrogenicity.

The perils of climate change: In utero exposure to temperature variability and birth outcomes in the Andean region.

PubMed

Molina, Oswaldo; Saldarriaga, Victor

2017-02-01

The discussion on the effects of climate change on human activity has primarily focused on how increasing temperature levels can impair human health. However, less attention has been paid to the effect of increased climate variability on health. We investigate how in utero exposure to temperature variability, measured as the fluctuations relative to the historical local temperature mean, affects birth outcomes in the Andean region. Our results suggest that exposure to a temperate one standard deviation relative to the municipality's long-term temperature mean during pregnancy reduces birth weight by 20g. and increases the probability a child is born with low birth weight by a 0.7 percentage point. We also explore potential channels driving our results and find some evidence that increased temperature variability can lead to a decrease in health care and increased food insecurity during pregnancy. Copyright © 2016 Elsevier B.V. All rights reserved.

Measurements of Solar Ultraviolet Radiation Exposure at Work and at Leisure in Danish Workers.

PubMed

Grandahl, Kasper; Eriksen, Paul; Ibler, Kristina Sophie; Bonde, Jens Peter; Mortensen, Ole Steen

2018-03-30

Exposure to solar ultraviolet radiation is the main cause of skin cancer and may well present an occupational health and safety problem. In Denmark, skin cancer is a common disease in the general population, but detailed data on solar ultraviolet radiation exposure among outdoor workers are lacking. The aim of this study was to provide objective measurements of solar ultraviolet radiation exposure on working days and at leisure and compare levels of exposure between groups of mainly outdoor, equal-parts-outdoor-and-indoor and indoor workers. To this end, UV-B dosimeters with an aluminum gallium nitride (AlGaN) photodiode detector were used to measure the solar ultraviolet radiation exposure of 457 workers in the Danish summer season. Presented as semi-annual standard erythemal dose (SED) on working days, respectively, at leisure, the results are for mainly outdoor workers 214.2 SED and 64.8 SED, equal-parts-outdoor-and-indoor workers 131.4 SED and 64.8 SED, indoor workers 55.8 SED and 57.6 SED. The daily SED by month is significantly different (α = 0.05) between mainly outdoor, equal-parts-outdoor-and-indoor and indoor workers and across professional groups; some of which are exposed at very high levels that is roofers 361.8 SED. These findings substantiate that exposure to solar ultraviolet radiation is indeed an occupational health and safety problem in Denmark. © 2018 The Authors. Photochemistry and Photobiology published by Wiley Periodicals, Inc. on behalf of American Society for Photobiology.

The NASA-Sponsored Study of Cataract in Astronauts (NASCA). Relationship of Exposure to Radiation in Space and the Risk of Cataract Incidence and Progression. Report 1: Recruitment and Methodology

NASA Technical Reports Server (NTRS)

Chylack, Leo T.; Peterson, Leif E.; Feiveson, Alan H.; Wear, Mary; Manuel, F. Keith

2007-01-01

The NASA Study of Cataract in Astronauts (NASCA) is a five-year, multi-centered, investigation of lens opacification in populations of U.S. astronauts, military pilots, and ground-based (nonaviator) comparison participants. For astronauts, the explanatory variable of most interest is radiation exposure during space flight, however to properly evaluate its effect, the secondary effects of age, nutrition, general health, solar ocular exposure, and other confounding variables encountered in non-space flight must also be considered. NASCA contains an initial baseline, cross-sectional objective assessment of the severity of cortical (C), nuclear (N), and posterior subcapsular (PSC) lens opacification, and annual follow-on assessments of severity and progression of these opacities in the population of astronauts and in participants sampled from populations of military pilots and ground-based exposure controls. From these data, NASCA will estimate the degree to which space radiation affects lens opacification for astronauts and how the overall risks of each cataract type for astronauts compared with those of the other exposure control groups after adjusting for differences in age and other explanatory variables.

Prenatal coke: what's behind the smoke? Prenatal cocaine/alcohol exposure and school-age outcomes: the SCHOO-BE experience.

PubMed

Delaney-Black, V; Covington, C; Templin, T; Ager, J; Martier, S; Compton, S; Sokol, R

1998-06-21

Despite media reports and educators' concerns, little substantive data have been published to document or refute the emerging reports that children prenatally exposed to cocaine have serious behavioral problems in school. Recent pilot data from this institution have indeed demonstrated teacher-reported problem behaviors following prenatal cocaine exposure after controlling for the effects of prenatal alcohol use and cigarette exposure. Imperative in the study of prenatal exposure and child outcome is an acknowledgement of the influence of other control factors such as postnatal environment, secondary exposures, and parenting issues. We report preliminary evaluation from a large ongoing historical prospective study of prenatal cocaine exposure on school-age outcomes. The primary aim of this NIDA-funded study is to determine if a relationship exists between prenatal cocaine/alcohol exposures and school behavior and, if so, to determine if the relationship is characterized by a dose-response relationship. A secondary aim evaluates the relationship between prenatal cocaine/alcohol exposures and school achievement. Both relationships will be assessed in a black, urban sample of first grade students using multivariate statistical techniques for confounding as well as mediating and moderating prenatal and postnatal variables. A third aim is to evaluate the relationship between a general standardized classroom behavioral measure and a tool designed to tap the effects thought to be specific to prenatal cocaine exposure. This interdisciplinary research team can address these aims because of the existence of a unique, prospectively collected perinatal Database, funded in part by NIAAA and NICHD. The database includes repeated measures of cocaine, alcohol, and other substances for over 3,500 births since 1986. Information from this database is combined with information from the database of one of the largest public school systems in the nation. The final sample will be composed of over 600 first grade students for whom the independent variables, prenatal cocaine/alcohol exposures, were prospectively assessed and quantified at the university maternity center. After informed consent, the primary dependent variable, school behavior, is assessed, using the PROBS-14 (a teacher consensus developed instrument), the Child Behavior Check List, and the Conners' Teacher Rating Scale. The secondary dependent measure, school achievement, is measured by the Metropolitan Achievement Text and the Test of Early Reading Ability. Control variables, such as the environment and parenting, are measured by several instruments aimed at capturing the child and family ecology since birth. All analyses will be adjusted as appropriate for prospectively gathered control variables such as perinatal risk, neonatal risk, and other prenatal drug and cigarette exposures. Further adjustment will be made for postnatal social risk factors which may influence outcome. Of particular concern are characteristics of the home (adaptation of HOME), parent (depression, stress), and neighborhood (violence exposure). Finally, postnatal exposure to lead and other drugs is being considered.

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.

Spatial variability in levels of benzene, formaldehyde, and total benzene, toluene, ethylbenzene and xylenes in New York City: a land-use regression study.

PubMed

Kheirbek, Iyad; Johnson, Sarah; Ross, Zev; Pezeshki, Grant; Ito, Kazuhiko; Eisl, Holger; Matte, Thomas

2012-07-31

Hazardous air pollutant exposures are common in urban areas contributing to increased risk of cancer and other adverse health outcomes. While recent analyses indicate that New York City residents experience significantly higher cancer risks attributable to hazardous air pollutant exposures than the United States as a whole, limited data exist to assess intra-urban variability in air toxics exposures. To assess intra-urban spatial variability in exposures to common hazardous air pollutants, street-level air sampling for volatile organic compounds and aldehydes was conducted at 70 sites throughout New York City during the spring of 2011. Land-use regression models were developed using a subset of 59 sites and validated against the remaining 11 sites to describe the relationship between concentrations of benzene, total BTEX (benzene, toluene, ethylbenzene, xylenes) and formaldehyde to indicators of local sources, adjusting for temporal variation. Total BTEX levels exhibited the most spatial variability, followed by benzene and formaldehyde (coefficient of variation of temporally adjusted measurements of 0.57, 0.35, 0.22, respectively). Total roadway length within 100 m, traffic signal density within 400 m of monitoring sites, and an indicator of temporal variation explained 65% of the total variability in benzene while 70% of the total variability in BTEX was accounted for by traffic signal density within 450 m, density of permitted solvent-use industries within 500 m, and an indicator of temporal variation. Measures of temporal variation, traffic signal density within 400 m, road length within 100 m, and interior building area within 100 m (indicator of heating fuel combustion) predicted 83% of the total variability of formaldehyde. The models built with the modeling subset were found to predict concentrations well, predicting 62% to 68% of monitored values at validation sites. Traffic and point source emissions cause substantial variation in street-level exposures to common toxic volatile organic compounds in New York City. Land-use regression models were successfully developed for benzene, formaldehyde, and total BTEX using spatial indicators of on-road vehicle emissions and emissions from stationary sources. These estimates will improve the understanding of health effects of individual pollutants in complex urban pollutant mixtures and inform local air quality improvement efforts that reduce disparities in exposure.

Psychopathology and Special Education Enrollment in Children with Prenatal Cocaine Exposure

PubMed Central

Levine, Todd P.; Lester, Barry; Lagasse, Linda; Shankaran, Seetha; Bada, Henrietta S.; Bauer, Charles R.; Whitaker, Toni M.; Higgins, Rosemary; Hammond, Jane; Roberts, Mary B.

2012-01-01

Objective This study evaluated how enrollment in special education services in 11 year old children relates to prenatal cocaine exposure, psychopathology, and other risk factors. Method Participants were 498 children enrolled in The Maternal Lifestyle Study, a prospective, longitudinal, multisite study examining outcomes of children with prenatal cocaine exposure. Logistic regression was used to examine the effect of prenatal cocaine exposure and psychopathology on enrollment in an individualized education plan (a designation specific to children with special education needs), with environmental, maternal, and infant medical variables as covariates. Results Prenatal cocaine exposure, an interaction of prenatal cocaine exposure and Oppositional Defiant Disorder, child Attention Deficit Hyperactivity Disorder, parent-reported internalizing behaviors, and teacher-reported externalizing behaviors, predicted enrollment in an individualized education plan. Other statistically significant variables in the model were male gender, low birth weight, being small for gestational age, white race, caregiver change, low socio-economic status, low child intelligence quotient, caregiver depression, and prenatal marijuana exposure. Conclusions Prenatal cocaine exposure increased the likelihood of receiving an individualized education plan with adjustment for covariates. Psychopathology also predicted this special education outcome, in combination with and independent of prenatal cocaine exposure. PMID:22487696

Temporal and spatial variation in pharmaceutical concentrations in an urban river system

USGS Publications Warehouse

Burns, Emily E.; Carter, Laura J.; Kolpin, Dana W.; Thomas-Oates, Jane; Boxall, Alistair B.A.

2018-01-01

Many studies have quantified pharmaceuticals in the environment, few however, have incorporated detailed temporal and spatial variability due to associated costs in terms of time and materials. Here, we target 33 physico-chemically diverse pharmaceuticals in a spatiotemporal exposure study into the occurrence of pharmaceuticals in the wastewater system and the Rivers Ouse and Foss (two diverse river systems) in the city of York, UK. Removal rates in two of the WWTPs sampled (a conventional activated sludge (CAS) and trickling filter plant) ranged from not eliminated (carbamazepine) to >99% (paracetamol). Data comparisons indicate that pharmaceutical exposures in river systems are highly variable regionally, in part due to variability in prescribing practices, hydrology, wastewater management, and urbanisation and that select annual median pharmaceutical concentrations observed in this study were higher than those previously observed in the European Union and Asia thus far. Significant spatial variability was found between all sites in both river systems, while seasonal variability was significant for 86% and 50% of compounds in the River Foss and Ouse, respectively. Seasonal variations in flow, in-stream attenuation, usage and septic effluent releases are suspected drivers behind some of the observed temporal exposure variability. When the data were used to evaluate a simple environmental exposure model for pharmaceuticals, mean ratios of predicted environmental concentrations (PECs), obtained using the model, to measured environmental concentrations (MECs) were 0.51 and 0.04 for the River Foss and River Ouse, respectively. Such PEC/MEC ratios indicate that the model underestimates actual concentrations in both river systems, but to a much greater extent in the larger River Ouse.

Incorporating twitter-based human activity information in spatial analysis of crashes in urban areas.

PubMed

Bao, Jie; Liu, Pan; Yu, Hao; Xu, Chengcheng

2017-09-01

The primary objective of this study was to investigate how to incorporate human activity information in spatial analysis of crashes in urban areas using Twitter check-in data. This study used the data collected from the City of Los Angeles in the United States to illustrate the procedure. The following five types of data were collected: crash data, human activity data, traditional traffic exposure variables, road network attributes and social-demographic data. A web crawler by Python was developed to collect the venue type information from the Twitter check-in data automatically. The human activities were classified into seven categories by the obtained venue types. The collected data were aggregated into 896 Traffic Analysis Zones (TAZ). Geographically weighted regression (GWR) models were developed to establish a relationship between the crash counts reported in a TAZ and various contributing factors. Comparative analyses were conducted to compare the performance of GWR models which considered traditional traffic exposure variables only, Twitter-based human activity variables only, and both traditional traffic exposure and Twitter-based human activity variables. The model specification results suggested that human activity variables significantly affected the crash counts in a TAZ. The results of comparative analyses suggested that the models which considered both traditional traffic exposure and human activity variables had the best goodness-of-fit in terms of the highest R 2 and lowest AICc values. The finding seems to confirm the benefits of incorporating human activity information in spatial analysis of crashes using Twitter check-in data. Copyright © 2017 Elsevier Ltd. All rights reserved.

RELIABILITY OF BIOMARKERS OF PESTICIDE EXPOSURE AMONG CHILDREN AND ADULTS IN CTEPP OHIO

EPA Science Inventory

Urinary biomarkers offer the potential for providing an efficient tool for exposure classification by reflecting the aggregate of all exposure routes. Substantial variability observed in urinary pesticide metabolite concentrations over short periods of time, however, has cast so...

Simulated response and effects to oil exposure in an estuarine fish species

EPA Science Inventory

Experimental toxicity data alone lack ecological relevance to assess more realistic situations, such as variable exposure to a contaminant and long-term impact. Evaluating the implications of sublethal effects or behavioral response to exposure requires long-term, population-leve...

Exposure Classification and Temporal Variability in Urinary Bisphenol A Concentrations among Couples in Utah--The HOPE Study.

PubMed

Cox, Kyley J; Porucznik, Christina A; Anderson, David J; Brozek, Eric M; Szczotka, Kathryn M; Bailey, Nicole M; Wilkins, Diana G; Stanford, Joseph B

2016-04-01

Bisphenol A (BPA) is an endocrine disruptor and potential reproductive toxicant, but results of epidemiologic studies have been mixed and have been criticized for inadequate exposure assessment that often relies on a single measurement. Our goal was to describe the distribution of BPA concentrations in serial urinary specimens, assess temporal variability, and provide estimates of exposure classification when randomly selected samples are used to predict average exposure. We collected and analyzed 2,614 urine specimens from 83 Utah couples beginning in 2012. Female participants collected daily first-morning urine specimens during one to two menstrual cycles and male partners collected specimens during the woman's fertile window for each cycle. We measured urinary BPA concentrations and calculated geometric means (GM) for each cycle, characterized the distribution of observed values and temporal variability using intraclass correlation coefficients, and performed surrogate category analyses to determine how well repeat samples could classify exposure. The GM urine BPA concentration was 2.78 ng/mL among males and 2.44 ng/mL among females. BPA had a high degree of variability among both males (ICC = 0.18; 95% CI: 0.11, 0.26) and females (ICC = 0.11; 95% CI: 0.08, 0.16). Based on our more stringent surrogate category analysis, to reach proportions ≥ 0.80 for sensitivity, specificity, and positive predictive value (PPV) among females, 6 and 10 repeat samples for the high and low tertiles, respectively, were required. For the medium tertile, specificity reached 0.87 with 10 repeat samples, but even with 11 samples, sensitivity and PPV did not exceed 0.36. Five repeat samples, among males, yielded sensitivity and PPV values ≥ 0.75 for the high and low tertiles, but, similar to females, classification for the medium tertile was less accurate. Repeated urinary specimens are required to characterize typical BPA exposure. Cox KJ, Porucznik CA, Anderson DJ, Brozek EM, Szczotka KM, Bailey NM, Wilkins DG, Stanford JB. 2016. Exposure classification and temporal variability in urinary bisphenol A concentrations among couples in Utah-the HOPE study. Environ Health Perspect 124:498-506; http://dx.doi.org/10.1289/ehp.1509752.

A new exposure metric for traffic-related air pollution? An analysis of determinants of hopanes in settled indoor house dust.

PubMed

Sbihi, Hind; Brook, Jeffrey R; Allen, Ryan W; Curran, Jason H; Dell, Sharon; Mandhane, Piush; Scott, James A; Sears, Malcolm R; Subbarao, Padmaja; Takaro, Timothy K; Turvey, Stuart E; Wheeler, Amanda J; Brauer, Michael

2013-06-19

Exposure to traffic-related air pollution (TRAP) can adversely impact health but epidemiologic studies are limited in their abilities to assess long-term exposures and incorporate variability in indoor pollutant infiltration. In order to examine settled house dust levels of hopanes, engine lubricating oil byproducts found in vehicle exhaust, as a novel TRAP exposure measure, dust samples were collected from 171 homes in five Canadian cities and analyzed by gas chromatography-mass spectrometry. To evaluate source contributions, the relative abundance of the highest concentration hopane monomer in house dust was compared to that in outdoor air. Geographic variables related to TRAP emissions and outdoor NO2 concentrations from city-specific TRAP land use regression (LUR) models were calculated at each georeferenced residence location and assessed as predictors of variability in dust hopanes. Hopanes relative abundance in house dust and ambient air were significantly correlated (Pearson's r=0.48, p<0.05), suggesting that dust hopanes likely result from traffic emissions. The proportion of variance in dust hopanes concentrations explained by LUR NO2 was less than 10% in Vancouver, Winnipeg and Toronto while the correlations in Edmonton and Windsor explained 20 to 40% of the variance. Modeling with household factors such as air conditioning and shoe removal along with geographic predictors related to TRAP generally increased the proportion of explained variability (10-80%) in measured indoor hopanes dust levels. Hopanes can consistently be detected in house dust and may be a useful tracer of TRAP exposure if determinants of their spatiotemporal variability are well-characterized, and when home-specific factors are considered.

Variability of Organophosphorous Pesticide Metabolite Levels in Spot and 24-hr Urine Samples Collected from Young Children during 1 Week

PubMed Central

Kogut, Katherine; Eisen, Ellen A.; Jewell, Nicholas P.; Quirós-Alcalá, Lesliam; Castorina, Rosemary; Chevrier, Jonathan; Holland, Nina T.; Barr, Dana Boyd; Kavanagh-Baird, Geri; Eskenazi, Brenda

2012-01-01

Background: Dialkyl phosphate (DAP) metabolites in spot urine samples are frequently used to characterize children’s exposures to organophosphorous (OP) pesticides. However, variable exposure and short biological half-lives of OP pesticides could result in highly variable measurements, leading to exposure misclassification. Objective: We examined within- and between-child variability in DAP metabolites in urine samples collected during 1 week. Methods: We collected spot urine samples over 7 consecutive days from 25 children (3–6 years of age). On two of the days, we collected 24-hr voids. We assessed the reproducibility of urinary DAP metabolite concentrations and evaluated the sensitivity and specificity of spot urine samples as predictors of high (top 20%) or elevated (top 40%) weekly average DAP metabolite concentrations. Results: Within-child variance exceeded between-child variance by a factor of two to eight, depending on metabolite grouping. Although total DAP concentrations in single spot urine samples were moderately to strongly associated with concentrations in same-day 24-hr samples (r ≈ 0.6–0.8, p < 0.01), concentrations in spot samples collected > 1 day apart and in 24-hr samples collected 3 days apart were weakly correlated (r ≈ –0.21 to 0.38). Single spot samples predicted high (top 20%) and elevated (top 40%) full-week average total DAP excretion with only moderate sensitivity (≈ 0.52 and ≈ 0.67, respectively) but relatively high specificity (≈ 0.88 and ≈ 0.78, respectively). Conclusions: The high variability we observed in children’s DAP metabolite concentrations suggests that single-day urine samples provide only a brief snapshot of exposure. Sensitivity analyses suggest that classification of cumulative OP exposure based on spot samples is prone to type 2 classification errors. PMID:23052012

A new exposure metric for traffic-related air pollution? An analysis of determinants of hopanes in settled indoor house dust

PubMed Central

2013-01-01

Background Exposure to traffic-related air pollution (TRAP) can adversely impact health but epidemiologic studies are limited in their abilities to assess long-term exposures and incorporate variability in indoor pollutant infiltration. Methods In order to examine settled house dust levels of hopanes, engine lubricating oil byproducts found in vehicle exhaust, as a novel TRAP exposure measure, dust samples were collected from 171 homes in five Canadian cities and analyzed by gas chromatography–mass spectrometry. To evaluate source contributions, the relative abundance of the highest concentration hopane monomer in house dust was compared to that in outdoor air. Geographic variables related to TRAP emissions and outdoor NO2 concentrations from city-specific TRAP land use regression (LUR) models were calculated at each georeferenced residence location and assessed as predictors of variability in dust hopanes. Results Hopanes relative abundance in house dust and ambient air were significantly correlated (Pearson’s r=0.48, p<0.05), suggesting that dust hopanes likely result from traffic emissions. The proportion of variance in dust hopanes concentrations explained by LUR NO2 was less than 10% in Vancouver, Winnipeg and Toronto while the correlations in Edmonton and Windsor explained 20 to 40% of the variance. Modeling with household factors such as air conditioning and shoe removal along with geographic predictors related to TRAP generally increased the proportion of explained variability (10-80%) in measured indoor hopanes dust levels. Conclusions Hopanes can consistently be detected in house dust and may be a useful tracer of TRAP exposure if determinants of their spatiotemporal variability are well-characterized, and when home-specific factors are considered. PMID:23782977

The relationship between ultraviolet radiation exposure and vitamin D status.

PubMed

Engelsen, Ola

2010-05-01

This paper reviews the main factors influencing the synthesis of vitamin D, with particular focus on ultraviolet radiation exposure. On the global level, the main source of vitamin D is the sun. The effect of solar radiation on vitamin D synthesis depends to some extent on the initial vitamin D levels. At moderate to high latitudes, diet becomes an increasingly important source of vitamin D due to decreased solar intensity and cold temperatures, which discourage skin exposure. During the mid-winter season, these factors result in decreased solar radiation exposure, hindering extensively the synthesis of vitamin D in these populations.

The effectiveness of an educational intervention to improve knowledge and perceptions for reducing organophosphate pesticide exposure among Indonesian and South Australian migrant farmworkers

PubMed Central

Suratman, Suratman; Ross, Kirstin E; Babina, Kateryna; Edwards, John William

2016-01-01

Background Farmworkers are at risk of exposure to organophosphate pesticides (OPs). Improvements of knowledge and perceptions about organophosphate (OP) exposure may be of benefit for the reduction in OP exposure. Purpose The purpose of this study was to examine the effectiveness of an educational intervention to improve knowledge and perceptions for reducing OP exposure among Indonesian and South Australian (SA) migrant farmworkers. Methods This was a quasi-experimental study. The educational intervention used a method of group communication for 30 Indonesian farmworkers and individual communication for seven SA migrant farmworkers. Knowledge and perceptions about OP exposure were measured pre-intervention and 3 months after the intervention. Results Unadjusted intervention effects at follow-up showed statistically significantly improved scores of knowledge (both adverse effects of OPs and self-protection from OP exposure), perceived susceptibility, and perceived barriers among Indonesian farmworkers compared with SA migrant farmworkers. Furthermore, these four significant variables in the unadjusted model and the two other variables (perceived severity and perceived benefits) were statistically significant after being adjusted for the level of education and years working as a farmworker. In contrast, knowledge about adverse effects of OPs was the only variable that was statistically significantly improved among SA migrant farmworkers. The results of this study suggests educational interventions using a method of group communication could be more effective than using individual intervention. Conclusion These improvements provide starting points to change health behavior of farmworkers, particularly to reduce OP exposure, both at the workplace and at home. PMID:26855602

Modular Exposure Disaggregation Methodologies for Catastrophe Modelling using GIS and Remotely-Sensed Data

NASA Astrophysics Data System (ADS)

Foulser-Piggott, R.; Saito, K.; Spence, R.

2012-04-01

Loss estimates produced by catastrophe models are dependent on the quality of the input data, including both the hazard and exposure data. Currently, some of the exposure data input into a catastrophe model is aggregated over an area and therefore an estimate of the risk in this area may have a low level of accuracy. In order to obtain a more detailed and accurate loss estimate, it is necessary to have higher resolution exposure data. However, high resolution exposure data is not commonly available worldwide and therefore methods to infer building distribution and characteristics at higher resolution from existing information must be developed. This study is focussed on the development of disaggregation methodologies for exposure data which, if implemented in current catastrophe models, would lead to improved loss estimates. The new methodologies developed for disaggregating exposure data make use of GIS, remote sensing and statistical techniques. The main focus of this study is on earthquake risk, however the methods developed are modular so that they may be applied to different hazards. A number of different methods are proposed in order to be applicable to different regions of the world which have different amounts of data available. The new methods give estimates of both the number of buildings in a study area and a distribution of building typologies, as well as a measure of the vulnerability of the building stock to hazard. For each method, a way to assess and quantify the uncertainties in the methods and results is proposed, with particular focus on developing an index to enable input data quality to be compared. The applicability of the methods is demonstrated through testing for two study areas, one in Japan and the second in Turkey, selected because of the occurrence of recent and damaging earthquake events. The testing procedure is to use the proposed methods to estimate the number of buildings damaged at different levels following a scenario earthquake event. This enables the results of the models to be compared with real data and the relative performance of the different methodologies to be evaluated. A sensitivity analysis is also conducted for two main reasons. Firstly, to determine the key input variables in the methodology that have the most significant impact on the resulting loss estimate. Secondly, to enable the uncertainty in the different approaches to be quantified and therefore provide a range of uncertainty in the loss estimates.

Variable Effects of Exposure to Formulated Microbicides on Antibiotic Susceptibility in Firmicutes and Proteobacteria

PubMed Central

Forbes, Sarah; Knight, Christopher G.; Cowley, Nicola L.; Amézquita, Alejandro; McClure, Peter; Humphreys, Gavin

2016-01-01

ABSTRACT Microbicides are broad-spectrum antimicrobial agents that generally interact with multiple pharmacological targets. While they are widely deployed in disinfectant, antiseptic, and preservative formulations, data relating to their potential to select for microbicide or antibiotic resistance have been generated mainly by testing the compounds in much simpler aqueous solutions. In the current investigation, antibiotic susceptibility was determined for bacteria that had previously exhibited decreased microbicide susceptibility following repeated exposure to microbicides either in formulation with sequestrants and surfactants or in simple aqueous solution. Statistically significant increases in antibiotic susceptibility occurred for 12% of bacteria after exposure to microbicides in formulation and 20% of bacteria after exposure to microbicides in aqueous solutions, while 22% became significantly less susceptible to the antibiotics, regardless of formulation. Of the combinations of a bacterium and an antibiotic for which British Society for Antimicrobial Chemotherapy breakpoints are available, none became resistant. Linear modeling taking into account phylogeny, microbicide, antibiotic, and formulation identified small but significant effects of formulation that varied depending on the bacterium and microbicide. Adaptation to formulated benzalkonium chloride in particular was more likely to increase antibiotic susceptibility than adaptation to the simple aqueous solution. In conclusion, bacterial adaptation through repeated microbicide exposure was associated with both increases and decreases in antibiotic susceptibility. Formulation of the microbicide to which the bacteria had previously adapted had an identifiable effect on antibiotic susceptibility, but it effect was typically small relative to the differences observed among microbicides. Susceptibility changes resulting in resistance were not observed. IMPORTANCE The safety of certain microbicide applications has been questioned due to the possibility that microbicide exposure could select for microbicide and antibiotic resistance. Evidence that this may happen is based mainly on in vitro experiments where bacteria have been exposed to microbicides in aqueous solution. Microbicides are, however, normally deployed in products formulated with surfactants, sequestrants, and other compounds. While this may influence the frequency and extent of susceptibility changes, few studies reported in the literature have assessed this. In the current investigation, therefore, we have investigated changes in antibiotic susceptibility in bacteria which exhibited decreased microbicide susceptibility following repeated exposure to microbicides in simple aqueous solutions and in formulation. We report that the microbicide formulation had an identifiable effect on antibiotic susceptibility, but it was typically small relative to the differences observed among microbicides. We did not observe susceptibility changes resulting in resistance. PMID:27060123

Statistical modeling of crystalline silica exposure by trade in the construction industry using a database compiled from the literature.

PubMed

Sauvé, Jean-François; Beaudry, Charles; Bégin, Denis; Dion, Chantal; Gérin, Michel; Lavoué, Jérôme

2012-09-01

A quantitative determinants-of-exposure analysis of respirable crystalline silica (RCS) levels in the construction industry was performed using a database compiled from an extensive literature review. Statistical models were developed to predict work-shift exposure levels by trade. Monte Carlo simulation was used to recreate exposures derived from summarized measurements which were combined with single measurements for analysis. Modeling was performed using Tobit models within a multimodel inference framework, with year, sampling duration, type of environment, project purpose, project type, sampling strategy and use of exposure controls as potential predictors. 1346 RCS measurements were included in the analysis, of which 318 were non-detects and 228 were simulated from summary statistics. The model containing all the variables explained 22% of total variability. Apart from trade, sampling duration, year and strategy were the most influential predictors of RCS levels. The use of exposure controls was associated with an average decrease of 19% in exposure levels compared to none, and increased concentrations were found for industrial, demolition and renovation projects. Predicted geometric means for year 1999 were the highest for drilling rig operators (0.238 mg m(-3)) and tunnel construction workers (0.224 mg m(-3)), while the estimated exceedance fraction of the ACGIH TLV by trade ranged from 47% to 91%. The predicted geometric means in this study indicated important overexposure compared to the TLV. However, the low proportion of variability explained by the models suggests that the construction trade is only a moderate predictor of work-shift exposure levels. The impact of the different tasks performed during a work shift should also be assessed to provide better management and control of RCS exposure levels on construction sites.

Pesticide exposure assessment for surface waters in the EU. Part 1: Some comments on the current procedure.

PubMed

Bach, Martin; Diesner, Mirjam; Großmann, Dietlinde; Guerniche, Djamal; Hommen, Udo; Klein, Michael; Kubiak, Roland; Müller, Alexandra; Priegnitz, Jan; Reichenberger, Stefan; Thomas, Kai; Trapp, Matthias

2016-07-01

In 2001, the European Commission introduced a risk assessment project known as FOCUS (FOrum for the Coordination of pesticide fate models and their USe) for the surface water risk assessment of active substances in the European Union. Even for the national authorisation of plant protection products (PPPs), the vast majority of EU member states still refer to the four runoff and six drainage scenarios selected by the FOCUS Surface Water Workgroup. However, our study, as well as the European Food Safety Authority (EFSA), has stated the need for various improvements. Current developments in pesticide exposure assessment mainly relate to two processes. Firstly, predicted environmental concentrations (PECs) of pesticides are calculated by introducing model input variables such as weather conditions, soil properties and substance fate parameters that have a probabilistic nature. Secondly, spatially distributed PECs for soil-climate scenarios are derived on the basis of an analysis of geodata. Such approaches facilitate the calculation of a spatiotemporal cumulative distribution function (CDF) of PECs for a given area of interest and are subsequently used to determine an exposure concentration endpoint as a given percentile of the CDF. For national PPP authorisation, we propose that, in the future, exposure endpoints should be determined from the overall known statistical PEC population for an area of interest, and derived for soil and climate conditions specific to the particular member state. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Methodology Series Module 1: Cohort Studies

PubMed Central

Setia, Maninder Singh

2016-01-01

Cohort design is a type of nonexperimental or observational study design. In a cohort study, the participants do not have the outcome of interest to begin with. They are selected based on the exposure status of the individual. They are then followed over time to evaluate for the occurrence of the outcome of interest. Some examples of cohort studies are (1) Framingham Cohort study, (2) Swiss HIV Cohort study, and (3) The Danish Cohort study of psoriasis and depression. These studies may be prospective, retrospective, or a combination of both of these types. Since at the time of entry into the cohort study, the individuals do not have outcome, the temporality between exposure and outcome is well defined in a cohort design. If the exposure is rare, then a cohort design is an efficient method to study the relation between exposure and outcomes. A retrospective cohort study can be completed fast and is relatively inexpensive compared with a prospective cohort study. Follow-up of the study participants is very important in a cohort study, and losses are an important source of bias in these types of studies. These studies are used to estimate the cumulative incidence and incidence rate. One of the main strengths of a cohort study is the longitudinal nature of the data. Some of the variables in the data will be time-varying and some may be time independent. Thus, advanced modeling techniques (such as fixed and random effects models) are useful in analysis of these studies. PMID:26955090

Methodology Series Module 1: Cohort Studies.

PubMed

Setia, Maninder Singh

2016-01-01

Cohort design is a type of nonexperimental or observational study design. In a cohort study, the participants do not have the outcome of interest to begin with. They are selected based on the exposure status of the individual. They are then followed over time to evaluate for the occurrence of the outcome of interest. Some examples of cohort studies are (1) Framingham Cohort study, (2) Swiss HIV Cohort study, and (3) The Danish Cohort study of psoriasis and depression. These studies may be prospective, retrospective, or a combination of both of these types. Since at the time of entry into the cohort study, the individuals do not have outcome, the temporality between exposure and outcome is well defined in a cohort design. If the exposure is rare, then a cohort design is an efficient method to study the relation between exposure and outcomes. A retrospective cohort study can be completed fast and is relatively inexpensive compared with a prospective cohort study. Follow-up of the study participants is very important in a cohort study, and losses are an important source of bias in these types of studies. These studies are used to estimate the cumulative incidence and incidence rate. One of the main strengths of a cohort study is the longitudinal nature of the data. Some of the variables in the data will be time-varying and some may be time independent. Thus, advanced modeling techniques (such as fixed and random effects models) are useful in analysis of these studies.

Factors associated with elevated blood lead concentrations in children in Karachi, Pakistan.

PubMed Central

Rahbar, Mohammad Hossein; White, Franklin; Agboatwalla, Mubina; Hozhabri, Siroos; Luby, Stephen

2002-01-01

OBJECTIVES: To confirm whether blood lead concentrations in Karachi were as high as reported in 1989 and to identify which types of exposure to lead contribute most to elevated blood lead concentrations in children in Karachi. METHODS: A total of 430 children aged 36-60 months were selected through a geographically stratified design from the city centre, two suburbs, a rural community and an island situated within the harbour at Karachi. Blood samples were collected from children and a pretested questionnaire was administered to assess the effect of various types of exposure. Cooked food, drinking-water and house dust samples were collected from households. FINDINGS: About 80% of children had blood lead concentrations 10 g/dl, with an overall mean of 15.6 g/dl. At the 5% level of significance, houses nearer to the main intersection in the city centre, application of surma to children's eyes, father's exposure to lead at workplace, parents' illiteracy and child's habit of hand- to-mouth activity were among variables associated with elevated lead concentrations in blood. CONCLUSION: These findings are of public health concern, as most children in Karachi are likely to suffer some degree of intellectual impairment as a result of environmental lead exposure. We believe that there is enough evidence of the continuing problem of lead in petrol to prompt the petroleum industry to take action. The evidence also shows the need for appropriate interventions in reducing the burden due to other factors associated with this toxic element. PMID:12471396

Design of a WSN for the Sampling of Environmental Variability in Complex Terrain

PubMed Central

Martín-Tardío, Miguel A.; Felicísimo, Ángel M.

2014-01-01

In-situ environmental parameter measurements using sensor systems connected to a wireless network have become widespread, but the problem of monitoring large and mountainous areas by means of a wireless sensor network (WSN) is not well resolved. The main reasons for this are: (1) the environmental variability distribution is unknown in the field; (2) without this knowledge, a huge number of sensors would be necessary to ensure the complete coverage of the environmental variability and (3) WSN design requirements, for example, effective connectivity (intervisibility), limiting distances and controlled redundancy, are usually solved by trial and error. Using temperature as the target environmental variable, we propose: (1) a method to determine the homogeneous environmental classes to be sampled using the digital elevation model (DEM) and geometric simulations and (2) a procedure to determine an effective WSN design in complex terrain in terms of the number of sensors, redundancy, cost and spatial distribution. The proposed methodology, based on geographic information systems and binary integer programming can be easily adapted to a wide range of applications that need exhaustive and continuous environmental monitoring with high spatial resolution. The results show that the WSN design is perfectly suited to the topography and the technical specifications of the sensors, and provides a complete coverage of the environmental variability in terms of Sun exposure. However these results still need be validated in the field and the proposed procedure must be refined. PMID:25412218

An Upper Bound for Population Exposure Variability (SOT)

EPA Science Inventory

Tools for the rapid assessment of exposure potential are needed in order to put the results of rapidly-applied tools for assessing biological activity, such as ToxCast® and other high throughput methodologies, into a quantitative exposure context. The ExpoCast models (Wambaugh et...

PERSONAL MEASURES OF POWER-FREQUENCY MAGNETIC FIELD EXPOSURE AMONG MEN FROM AN INFERTILITY CLINIC: DISTRIBUTION, TEMPORAL VARIABILITY AND CORRELATION WITH THEIR FEMALE PARTNERS' EXPOSURE

PubMed Central

Lewis, Ryan C.; Hauser, Russ; Maynard, Andrew D.; Neitzel, Richard L.; Wang, Lu; Kavet, Robert; Morey, Patricia; Ford, Jennifer B.; Meeker, John D.

2016-01-01

Power-frequency magnetic field exposure science as it relates to men and couples have not been explored despite the advantage of this information in the design and interpretation of reproductive health epidemiology studies. This analysis examined the distribution and temporal variability of exposures in men, and the correlation of exposures within couples using data from a longitudinal study of 25 men and their female partners recruited from an infertility clinic. The average and 90th percentile demonstrated fair to good reproducibility, whereas the maximum showed poor reproducibility over repeated sampling days, each separated by a median of 4.6 weeks. Average magnetic field exposures were also strongly correlated within couples, suggesting that one partner's data could be used as a surrogate in the absence of data from the other for this metric. Environment was also an important effect modifier in these explored matters. These issues should be considered in future relevant epidemiology studies. PMID:26705359

Role of Parent and Peer Relationships and Individual Characteristics in Middle School Children's Behavioral Outcomes in the Face of Community Violence

PubMed Central

Salzinger, Suzanne; Rosario, Margaret; Feldman, Richard S.; Ng-Mak, Daisy S.

2010-01-01

This study examines processes linking inner-city community violence exposure to subsequent internalizing and externalizing problems. Hypothesized risk and protective factors from three ecological domains -- children's parent and peer relationships and individual characteristics -- were examined for mediating, moderating or independent roles in predicting problem behavior among 667 children over three years of middle school. Mediation was not found. However, parent and peer variables moderated the association between exposure and internalizing problems. Under high exposure, normally protective factors (e.g., attachment to parents) were less effective in mitigating exposure's effects than under low exposure; attachment to friends was more effective. Individual competence was independently associated with decreased internalizing problems. Variables from all domains, and exposure, were independently associated with externalizing problems. Protective factors (e.g., parent attachment) predicted decreased problems; risk factors (e.g., friends' delinquency) predicted increased problems. Results indicate community violence reduction as essential in averting inner-city adolescents' poor behavioral outcomes. PMID:21643493

Human Plant Exposures Reported to a Regional (Southwestern) Poison Control Center Over 8 Years.

PubMed

Enfield, Ben; Brooks, Daniel E; Welch, Sharyn; Roland, Maureen; Klemens, Jane; Greenlief, Kim; Olson, Rachel; Gerkin, Richard D

2018-03-01

There is little published data about human plant exposures reported to US poison control centers (PCCs). A retrospective chart review of all reported plant exposures to a single regional PCC between January 1, 2003 and December 31, 2010 was done to understand better the characteristics of plant exposure cases. Specific generic plant codes were used to identify cases. Recorded variables included patient demographics, plant involved, exposure variables, symptoms, management site, treatments, and outcome. Univariate and multivariate regression was used to identify outcome predictors. A total of 6492 charts met inclusion criteria. The average age was 16.6 years (2 months-94 years); 52.4% were male. The most common exposure reason was unintentional (98%), and the majority (92.4%) occurred at the patient's home. Ingestions (58.3%) and dermal exposures (34.3%) accounted for most cases. Cactus (27.5%), oleander (12.5%), Lantana (5.7%), and Bougainvillea (3.8%) were most commonly involved. Symptoms developed in 47.1% of patients, and were more likely to occur following Datura (66.7%), and Morning Glory or Milkweed (25% each) exposures. Almost 94% of patients were managed onsite (home) and only 5.2% involved evaluation in a health care facility (HCF). Only 37 (0.6%) patients required hospital admission, and 2.9% of cases resulted in more than minimal effects. Exposures resulting in more than minimal clinical effects were predicted by several variables: abnormal vital signs (OR = 35.62), abnormal labs (OR = 14.87), and management at a HCF (OR = 7.37). Hospital admissions were increased for patients already at a HCF (OR = 54.01), abnormal vital signs (OR = 23.28), and intentional exposures (OR = 14.7). Plant exposures reported to our poison control center were typically unintentional ingestions occurring at home. Most patients were managed onsite and few developed significant symptoms.

Movie Smoking Exposure and Smoking Onset: A Longitudinal Study of Mediation Processes in a Representative Sample of U.S. Adolescents

PubMed Central

Wills, Thomas A.; Sargent, James D.; Stoolmiller, Mike; Gibbons, Frederick X.; Gerrard, Meg

2009-01-01

The authors tested 2 mechanisms for the relation of movie smoking exposure with onset of cigarette smoking in adolescence. Longitudinal data with 8-month follow-up were obtained from a representative sample of 6,522 U.S. adolescents, ages 10–14 years. Structural modeling analysis based on initial nonsmokers, which controlled for 10 covariates associated with movie exposure, showed that viewing more smoking in movies was related to increases in positive expectancies about smoking and increases in affiliation with smoking peers, and these variables were both related to smoking onset. A direct effect of movie exposure on smoking onset was also noted. Mediation findings were replicated across cross-sectional and longitudinal analyses. Tests for gender differences indicated that girls showed larger effects of movie exposure for some variables. Implications for policy and prevention research are discussed. PMID:18540724

Nonlinear heart rate variability measures under electromagnetic fields produced by GSM cellular phones.

PubMed

Parazzini, Marta; Ravazzani, Paolo; Thuroczy, György; Molnar, Ferenc B; Ardesi, Gianluca; Sacchettini, Alessio; Mainardi, Luca Tommaso

2013-06-01

This study was designed to assess the nonlinear dynamics of heart rate variability (HRV) during exposure to low-intensity EMFs. Twenty-six healthy young volunteers were subjected to a rest-to-stand protocol to evaluate autonomic nervous system in quiet condition (rest, vagal prevalence) and after a sympathetic activation (stand). The procedure was conducted twice in a double-blind design: once with a genuine EMFs exposure (GSM cellular phone at 900 MHz, 2 W) and once with a sham exposure (at least 24 h apart). During each session, three-lead electrocardiograms were recorded and RR series extracted off-line. The RR series were analyzed by nonlinear deterministic techniques in every phase of the protocol and during the different exposures. The analysis of the data shows there was no statistically significant effect due to GSM exposure on the nonlinear dynamics of HRV.

Airway responsiveness to methacholine, respiratory symptoms, and dust exposure levels in grain and flour mill workers in eastern France.

PubMed

Massin, N; Bohadana, A B; Wild, P; Kolopp-Sarda, M N; Toamain, J P

1995-06-01

Our goal was to assess the relation between dust exposure levels and the respiratory health status of workers in grain and flour mills in eastern France. We studied 118 male workers from 11 mills and 164 unexposed male controls. Dust concentration was measured by personal sampling methods. Outcome variables included respiratory symptoms, routine pulmonary function tests, and indices of airway responsiveness to methacholine. A great within- and between-area variability of inhalable dust concentration was found in all mills. A dose-response relationship was observed between dust exposure levels and chronic respiratory symptoms, suggesting that exposure to grain and flour dust may lead to chronic bronchitis. A significant relation was found between dust exposure and airway hyper-responsiveness; this finding is important since it has been hypothesized that the latter abnormality may lead to or be a predisposing factor in subsequent chronic, irreversible airflow obstruction.

Within and between Individual Variability of Exposure to Work-Related Musculoskeletal Disorder Risk Factors.

PubMed

Zare, Mohsen; Sagot, Jean-Claude; Roquelaure, Yves

2018-05-17

Industrial companies indicate a tendency to eliminate variations in operator strategies, particularly following implementation of the lean principle. Companies believe when the operators perform the same prescribed tasks, they have to execute them in the same manner (completing the same gestures and being exposed to the same risk factors). They attempt to achieve better product quality by standardizing and reducing operational leeway. However, operators adjust and modify ways of performing tasks to balance between their abilities and the requirements of the job. This study aims to investigate the variability of exposure to physical risk factors within and between operators when executing the same prescribed tasks. The Ergonomic Standard method was used to evaluate two workstations. Seven operators were observed thirty times between repeated cycle times at those workstations. The results revealed the variability of exposure to risk factors between and within operators in the repeated execution of the same tasks. Individual characteristics and operators' strategies might generate the variability of exposure to risk factors that may be an opportunity to reduce the risks of work-related musculoskeletal disorders (WR-MSDs). However, sometimes operators' strategies may cause overexposure to risk factors; operators most often adopt such strategies to undertake their tasks while reducing the workload.

Inhalation of ultrafine carbon particles alters heart rate and heart rate variability in people with type 2 diabetes.

PubMed

Vora, Rathin; Zareba, Wojciech; Utell, Mark J; Pietropaoli, Anthony P; Chalupa, David; Little, Erika L; Oakes, David; Bausch, Jan; Wiltshire, Jelani; Frampton, Mark W

2014-07-16

Diabetes may confer an increased risk for the cardiovascular health effects of particulate air pollution, but few human clinical studies of air pollution have included people with diabetes. Ultrafine particles (UFP, ≤100 nm in diameter) have been hypothesized to be an important component of particulate air pollution with regard to cardiovascular health effects. 17 never-smoker subjects 30-60 years of age, with stable type 2 diabetes but otherwise healthy, inhaled either filtered air (0-10 particles/cm3) or elemental carbon UFP (~107 particles/cm3, ~50 ug/m3, count median diameter 32 nm) by mouthpiece, for 2 hours at rest, in a double-blind, randomized, crossover study design. A digital 12-lead electrocardiogram (ECG) was recorded continuously for 48 hours, beginning 1 hour prior to exposure. Analysis of 5-minute segments of the ECG during quiet rest showed reduced high-frequency heart rate variability with UFP relative to air exposure (p = 0.014), paralleled by non-significant reductions in time-domain heart rate variability parameters. In the analysis of longer durations of the ECG, we found that UFP exposure increased the heart rate relative to air exposure. During the 21- to 45-hour interval after exposure, the average heart rate increased approximately 8 beats per minute with UFP, compared to 5 beats per minute with air (p = 0.045). There were no UFP effects on cardiac rhythm or repolarization. Inhalation of elemental carbon ultrafine particles alters heart rate and heart rate variability in people with type 2 diabetes. Our findings suggest that effects may occur and persist hours after a single 2-hour exposure.

Hypertension Does Not Alter the Increase in Cardiac Baroreflex Sensitivity Caused by Moderate Cold Exposure

PubMed Central

Hintsala, Heidi E.; Kiviniemi, Antti M.; Tulppo, Mikko P.; Helakari, Heta; Rintamäki, Hannu; Mäntysaari, Matti; Herzig, Karl-Heinz; Keinänen-Kiukaanniemi, Sirkka; Jaakkola, Jouni J. K.; Ikäheimo, Tiina M.

2016-01-01

Exposure to cold increases blood pressure and may contribute to higher wintertime cardiovascular morbidity and mortality in hypertensive people, but the mechanisms are not well-established. While hypertension does not alter responses of vagally-mediated heart rate variability to cold, it is not known how hypertension modifies baroreflex sensitivity (BRS) and blood pressure variability during cold exposure. Our study assessed this among untreated hypertensive men during short-term exposure comparable to habitual winter time circumstances in subarctic areas. We conducted a population-based recruitment of 24 untreated hypertensive and 17 men without hypertension (age 55–65 years) who underwent a whole-body cold exposure (−10°C, wind 3 m/s, winter clothes, 15 min, standing). Electrocardiogram and continuous blood pressure were measured to compute spectral powers of systolic blood pressure and heart rate variability at low (0.04–0.15 Hz) and high frequency (0.15–0.4 Hz) and spontaneous BRS at low frequency (LF). Comparable increases in BRS were detected in hypertensive men, from 2.6 (2.0, 4.2) to 3.8 (2.5, 5.1) ms/mmHg [median (interquartile range)], and in control group, from 4.3 (2.7, 5.0) to 4.4 (3.1, 7.1) ms/mmHg. Instead, larger increase (p < 0.05) in LF blood pressure variability was observed in control group; response as median (interquartile range): 8 (2, 14) mmHg2, compared with hypertensive group [0 (−13, 20) mmHg2]. Untreated hypertension does not disturb cardiovascular protective mechanisms during moderate cold exposure commonly occurring in everyday life. Blunted response of the estimate of peripheral sympathetic modulation may indicate higher tonic sympathetic activity and decreased sympathetic responsiveness to cold in hypertension. PMID:27313543

Frequency of sister-chromatid exchange among greenhouse farmers exposed to pesticides.

PubMed

Shaham, J; Kaufman, Z; Gurvich, R; Levi, Z

2001-04-05

Sister-chromatid exchange (SCE) was measured in peripheral lymphocytes of 104 greenhouse farmers exposed to pesticides and 44 unexposed workers. The results of SCEs are expressed in two variables: (a) mean number of SCEs per chromosome and, (b) proportion of high frequency cells (cells with more than eight SCEs). A high correlation was found between these two variables. The adjusted means of both SCEs variables were significantly higher among the farmers compared with the unexposed group (P < 0.01). Adjustment was made for smoking, age, education, and origin. The adjusted means of both SCE variables, were significantly elevated (P < 0.05) among the farmers who prepared and applied more than 70% of the pesticides by themselves compared with those who prepared and applied less than 70% of the pesticides by themselves. Both SCEs variables were also significantly elevated (P < 0.05) among farmers who were involved in more than 7.4 sprays per year compared with those with 7.4 or less sprays per year (P < 0.05). We found a tendency towards elevation of the two variables of SCEs among those who did not use protective measures while preparing the pesticides. Evaluation of the influence of years of exposure on the frequency of SCEs showed that the two variables of SCEs were higher among those farmers who were exposed to pesticides for more than 21 years than among those with less than 21 years of exposure. The variables that had the most influence on the elevation of SCEs were self-preparation of the pesticide mixtures and the number of sprayings per year. Because the farmers used a mixture of almost 24 different chemical classes it was impossible to attribute exposure to a specific pesticide or group of pesticides to single farmers. Our finding of a significant increase of SCEs frequency in peripheral lymphocytes in greenhouse farmers indicates a potential cytogenetic hazard due to pesticides exposure.

Use of portable exposure meters for comparing mobile phone base station radiation in different types of areas in the cities of Basel and Amsterdam.

PubMed

Urbinello, Damiano; Huss, Anke; Beekhuizen, Johan; Vermeulen, Roel; Röösli, Martin

2014-01-15

Radiofrequency electromagnetic fields (RF-EMF) are highly variable and differ considerably within as well as between areas. Exposure assessment studies characterizing spatial and temporal variation are limited so far. Our objective was to evaluate sources of data variability and the repeatability of daily measurements using portable exposure meters (PEMs). Data were collected at 12 days between November 2010 and January 2011 with PEMs in four different types of urban areas in the cities of Basel (BSL) and Amsterdam (AMS). Exposure from mobile phone base stations ranged from 0.30 to 0.53 V/m in downtown and business areas and in residential areas from 0.09 to 0.41 V/m. Analysis of variance (ANOVA) demonstrated that measurements from various days were highly reproducible (measurement duration of approximately 30 min) with only 0.6% of the variance of all measurements from mobile phone base station radiation being explained by the measurement day and only 0.2% by the measurement time (morning, noon, afternoon), whereas type of area (30%) and city (50%) explained most of the data variability. We conclude that mobile monitoring of exposure from mobile phone base station radiation with PEMs is useful due to the high repeatability of mobile phone base station exposure levels, despite the high spatial variation. © 2013.

City scale pollen concentration variability

NASA Astrophysics Data System (ADS)

van der Molen, Michiel; van Vliet, Arnold; Krol, Maarten

2016-04-01

Pollen are emitted in the atmosphere both in the country-side and in cities. Yet the majority of the population is exposed to pollen in cities. Allergic reactions may be induced by short-term exposure to pollen. This raises the question how variable pollen concentration in cities are in temporally and spatially, and how much of the pollen in cities are actually produced in the urban region itself. We built a high resolution (1 × 1 km) pollen dispersion model based on WRF-Chem to study a city's pollen budget and the spatial and temporal variability in concentration. It shows that the concentrations are highly variable, as a result of source distribution, wind direction and boundary layer mixing, as well as the release rate as a function of temperature, turbulence intensity and humidity. Hay Fever Forecasts based on such high resolution emission and physical dispersion modelling surpass traditional hay fever warning methods based on temperature sum methods. The model gives new insights in concentration variability, personal and community level exposure and prevention. The model will be developped into a new forecast tool to serve allergic people to minimize their exposure and reduce nuisance, coast of medication and sick leave. This is an innovative approach in hay fever warning systems.

Evaluation of exposure to electromagnetic radiofrequency radiation in the indoor workplace accessible to the public by the use of frequency-selective exposimeters.

PubMed

Gryz, Krzysztof; Karpowicz, Jolanta; Leszko, Wiesław; Zradziński, Patryk

2014-12-01

The aim of the study was to identify and assess electromagnetic radiofrequency radiation (EMRR) exposure in a workplace located in a publicly accessible environment, and represented by offices (where exposure is caused by various transmitters of local fixed indoor and outdoor wireless communication systems). The investigations were performed in 45 buildings (in urban and rural areas in various regions of Poland), using frequency-selective electric field strength (E-field) exposimeters sensitive to the EMRR with a frequency range of 88-2500 MHz, split into 12 sub-bands corresponding to the operating frequencies of typical EMRR sources. The variability of the E-field was analyzed for each frequency range and the total level of exposure by statistical parameters of recorded exposimetric profiles: minimum, maximum, median values and 25-75th - percentiles. The main sources of exposure to EMRR are mobile phone base transceiver stations (BTS) and radio-television transmitters (RTV). The frequency composition in a particular office depends on the building's location. The E-field recorded in buildings in urban and rural areas from the outdoor BTS did not exceed respectively: medians - 0.19 and 0.05 V/m, 75th percentiles -0.25 and 0.09 V/m. In buildings equipped with the indoor BTS antennas the E-field did not exceed: medians - 1 V/m, 75th percentiles - 1.8 V/m. Whereas in urban and rural areas, the median and 75th percentile values of the E-field recorded in buildings located near the RTV (within 1 km) did not exceed: 1.5 and 3.8 V/m or 0.4 and 0.8 V/m, for radio FM band or for TV bands, respectively. Investigations confirmed the practical applicability of the exposimetric measurements technique for evaluating parameters of worker's exposure in both frequency- and time-domain. The presented results show EMRR exposure of workers or general public in locations comparable to offices to be well below international limits.

Environmental tobacco smoke exposure and risk of breast cancer in nonsmoking women. An updated review and meta-analysis

PubMed Central

Lee, Peter N.; Hamling, Jan S.

2016-01-01

Abstract Context: In 2006, we reviewed the evidence on environmental tobacco smoke (ETS) and breast cancer in nonsmoking women. Since then various studies and reviews have been published but opinion remains divided. Objective: To provide an updated review. Methods: We extracted study details, derived relative risk (RR) estimates with confidence intervals (CIs) for various ETS exposure indices, and conducted meta-analyses. Results: The update increased the number of studies from 22 to 47. Using an index for each study most closely equivalent to “spouse ever smoked”, a weak but significant association was seen (random-effects RR = 1.15, 95% CI = 1.07–1.23). However, the estimates were heterogeneous: higher for Asian studies than for North American or European studies, higher for studies adjusting for fewer potential confounding variables, and close to 1.0 for prospective studies, regardless of whether or not they asked detailed questions on ETS exposure. The RR for eight prospective studies asking detailed questions was 1.003, 95% CI = 0.96–1.05. Risk was increased in premenopausal women (RR = 1.36, 95% CI = 1.15–1.60), but not postmenopausal women. Dose–response findings were similarly heterogeneous. No significant increase was seen for childhood or workplace exposure, but an increase was seen for total exposure (RR = 1.22, 95% CI = 1.09–1.37). Conclusions: Increases mainly derived from case-control studies are prone to recall bias. Study weaknesses and possible publication bias limit interpretation. Considering also the weak association of smoking with breast cancer, and the much lower exposures from ETS than from smoking, our analyses do not clearly demonstrate that ETS exposure increases risk of breast cancer in nonsmokers. More research is needed. PMID:27541291

High Throughput Exposure Modeling of Semi-Volatile Chemicals in Articles of Commerce (ACS)

EPA Science Inventory

Risk due to chemical exposure is a function of both chemical hazard and exposure. Near-field exposures to chemicals in consumer products are identified as the main drivers of exposure and yet are not well quantified or understood. The ExpoCast project is developing a model that e...

Modeling personal particle-bound polycyclic aromatic hydrocarbon (pb-pah) exposure in human subjects in Southern California.

PubMed

Wu, Jun; Tjoa, Thomas; Li, Lianfa; Jaimes, Guillermo; Delfino, Ralph J

2012-07-11

Exposure to polycyclic aromatic hydrocarbon (PAH) has been linked to various adverse health outcomes. Personal PAH exposures are usually measured by personal monitoring or biomarkers, which are costly and impractical for a large population. Modeling is a cost-effective alternative to characterize personal PAH exposure although challenges exist because the PAH exposure can be highly variable between locations and individuals in non-occupational settings. In this study we developed models to estimate personal inhalation exposures to particle-bound PAH (PB-PAH) using data from global positioning system (GPS) time-activity tracking data, traffic activity, and questionnaire information. We conducted real-time (1-min interval) personal PB-PAH exposure sampling coupled with GPS tracking in 28 non-smoking women for one to three sessions and one to nine days each session from August 2009 to November 2010 in Los Angeles and Orange Counties, California. Each subject filled out a baseline questionnaire and environmental and behavior questionnaires on their typical activities in the previous three months. A validated model was used to classify major time-activity patterns (indoor, in-vehicle, and other) based on the raw GPS data. Multiple-linear regression and mixed effect models were developed to estimate averaged daily and subject-level PB-PAH exposures. The covariates we examined included day of week and time of day, GPS-based time-activity and GPS speed, traffic- and roadway-related parameters, meteorological variables (i.e. temperature, wind speed, relative humidity), and socio-demographic variables and occupational exposures from the questionnaire. We measured personal PB-PAH exposures for 180 days with more than 6 h of valid data on each day. The adjusted R2 of the model was 0.58 for personal daily exposures, 0.61 for subject-level personal exposures, and 0.75 for subject-level micro-environmental exposures. The amount of time in vehicle (averaging 4.5% of total sampling time) explained 48% of the variance in daily personal PB-PAH exposure and 39% of the variance in subject-level exposure. The other major predictors of PB-PAH exposures included length-weighted traffic count, work-related exposures, and percent of weekday time. We successfully developed regression models to estimate PB-PAH exposures based on GPS-tracking data, traffic data, and simple questionnaire information. Time in vehicle was the most important determinant of personal PB-PAH exposure in this population. We demonstrated the importance of coupling real-time exposure measures with GPS time-activity tracking in personal air pollution exposure assessment.

Development and evaluation of alternative approaches for exposure assessment of multiple air pollutants in Atlanta, Georgia

EPA Science Inventory

Measurements from central site (CS) monitors are often used as estimates of exposure in air pollution epidemiological studies. As these measurements are typically limited in their spatiotemporal resolution, true exposure variability within a population is often obscured, leading ...

EFFECTS OF SUBCHRONIC EXPOSURE TO CONCENTRATED AMBIENT PARTICULATES ON ELECTROCARDIOGRAM AND HEART RATE VARIABILITY IN SPONTANEOUSLY HYPERTENSIVE RATS

EPA Science Inventory

Epidemiological studies have linked air pollution exposure to adverse respiratory health effects, especially in individuals with inflammatory airways disease. Symptomatic asthmatics appear to be at greatest risk. We previously demonstrated that exposure of rats to particulate...

Using Agent-Based Approaches to Characterize Exposure Related Behavior

EPA Science Inventory

The Tox21 initiative is generating data on biological activity, toxicity, and chemical properties for over 8,000 substances. One of the goals for EPA’s National Exposure Research Lab (NERL) is to assess the magnitude and variability in the public’s exposures to these ...

A single exposure to acrolein causes arrhythmogenesis, cardiac electrical dysfunction and decreased heart rate variability in hypertensive rats

EPA Science Inventory

Epidemiological studies demonstrate an association between cardiovascular morbidity, arrhythmias, and exposure to air toxicants such as acrolein. We hypothesized that a single exposure to acrolein would increase arrhythmias and cause changes in the electrocardiogram (ECG) of hype...

QIVIVE Approaches to Evaluate Interindividual Toxicokinetic Variability

EPA Science Inventory

Toxicokinetic (TK) variability across life-stages and populations can significantly impact the amount of chemical available systemically to elicit an effect despite similar external exposures. This variability is driven by physiologic (e.g., liver weights, blood flow rates, etc.)...

Modelling survival: exposure pattern, species sensitivity and uncertainty.

PubMed

Ashauer, Roman; Albert, Carlo; Augustine, Starrlight; Cedergreen, Nina; Charles, Sandrine; Ducrot, Virginie; Focks, Andreas; Gabsi, Faten; Gergs, André; Goussen, Benoit; Jager, Tjalling; Kramer, Nynke I; Nyman, Anna-Maija; Poulsen, Veronique; Reichenberger, Stefan; Schäfer, Ralf B; Van den Brink, Paul J; Veltman, Karin; Vogel, Sören; Zimmer, Elke I; Preuss, Thomas G

2016-07-06

The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test the ability of GUTS to predict survival of aquatic organisms across different pesticide exposure patterns, time scales and species. Firstly, using synthetic data, we identified experimental data requirements which allow for the estimation of all parameters of the GUTS proper model. Secondly, we assessed how well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates to build species sensitivity distributions for different exposure patterns. We find that GUTS adequately predicts survival across exposure patterns that vary over time. When toxicity is assessed for time-variable concentrations species may differ in their responses depending on the exposure profile. This can result in different species sensitivity rankings and safe levels. The interplay of exposure pattern and species sensitivity deserves systematic investigation in order to better understand how organisms respond to stress, including humans.

Modelling survival: exposure pattern, species sensitivity and uncertainty

NASA Astrophysics Data System (ADS)

Ashauer, Roman; Albert, Carlo; Augustine, Starrlight; Cedergreen, Nina; Charles, Sandrine; Ducrot, Virginie; Focks, Andreas; Gabsi, Faten; Gergs, André; Goussen, Benoit; Jager, Tjalling; Kramer, Nynke I.; Nyman, Anna-Maija; Poulsen, Veronique; Reichenberger, Stefan; Schäfer, Ralf B.; van den Brink, Paul J.; Veltman, Karin; Vogel, Sören; Zimmer, Elke I.; Preuss, Thomas G.

2016-07-01

The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test the ability of GUTS to predict survival of aquatic organisms across different pesticide exposure patterns, time scales and species. Firstly, using synthetic data, we identified experimental data requirements which allow for the estimation of all parameters of the GUTS proper model. Secondly, we assessed how well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates to build species sensitivity distributions for different exposure patterns. We find that GUTS adequately predicts survival across exposure patterns that vary over time. When toxicity is assessed for time-variable concentrations species may differ in their responses depending on the exposure profile. This can result in different species sensitivity rankings and safe levels. The interplay of exposure pattern and species sensitivity deserves systematic investigation in order to better understand how organisms respond to stress, including humans.

Estimated long-term outdoor air pollution concentrations in a cohort study

NASA Astrophysics Data System (ADS)

Beelen, Rob; Hoek, Gerard; Fischer, Paul; Brandt, Piet A. van den; Brunekreef, Bert

Several recent studies associated long-term exposure to air pollution with increased mortality. An ongoing cohort study, the Netherlands Cohort Study on Diet and Cancer (NLCS), was used to study the association between long-term exposure to traffic-related air pollution and mortality. Following on a previous exposure assessment study in the NLCS, we improved the exposure assessment methods. Long-term exposure to nitrogen dioxide (NO 2), nitrogen oxide (NO), black smoke (BS), and sulphur dioxide (SO 2) was estimated. Exposure at each home address ( N=21 868) was considered as a function of a regional, an urban and a local component. The regional component was estimated using inverse distance weighed interpolation of measurement data from regional background sites in a national monitoring network. Regression models with urban concentrations as dependent variables, and number of inhabitants in different buffers and land use variables, derived with a Geographic Information System (GIS), as predictor variables were used to estimate the urban component. The local component was assessed using a GIS and a digital road network with linked traffic intensities. Traffic intensity on the nearest road and on the nearest major road, and the sum of traffic intensity in a buffer of 100 m around each home address were assessed. Further, a quantitative estimate of the local component was estimated. The regression models to estimate the urban component explained 67%, 46%, 49% and 35% of the variances of NO 2, NO, BS, and SO 2 concentrations, respectively. Overall regression models which incorporated the regional, urban and local component explained 84%, 44%, 59% and 56% of the variability in concentrations for NO 2, NO, BS and SO 2, respectively. We were able to develop an exposure assessment model using GIS methods and traffic intensities that explained a large part of the variations in outdoor air pollution concentrations.

Variable Linezolid Exposure in Intensive Care Unit Patients-Possible Role of Drug-Drug Interactions.

PubMed

Töpper, Christoph; Steinbach, Cathérine L; Dorn, Christoph; Kratzer, Alexander; Wicha, Sebastian G; Schleibinger, Michael; Liebchen, Uwe; Kees, Frieder; Salzberger, Bernd; Kees, Martin G

2016-10-01

Standard doses of linezolid may not be suitable for all patient groups. Intensive care unit (ICU) patients in particular may be at risk of inadequate concentrations. This study investigated variability of drug exposure and its potential sources in this population. Plasma concentrations of linezolid were determined by high-performance liquid chromatography in a convenience sample of 20 ICU patients treated with intravenous linezolid 600 mg twice daily. Ultrafiltration applying physiological conditions (pH 7.4/37°C) was used to determine the unbound fraction. Individual pharmacokinetic (PK) parameters were estimated by population PK modeling. As measures of exposure to linezolid, area under the concentration-time curve (AUC) and trough concentrations (Cmin) were calculated and compared with published therapeutic ranges (AUC 200-400 mg*h/L, Cmin 2-10 mg/L). Coadministered inhibitors or inducers of cytochrome P450 and/or P-glycoprotein were noted. Data from 18 patients were included into the PK evaluation. Drug exposure was highly variable (median, range: AUC 185, 48-618 mg*h/L, calculated Cmin 2.92, 0.0062-18.9 mg/L), and only a minority of patients had values within the target ranges (6 and 7, respectively). AUC and Cmin were linearly correlated (R = 0.98), and classification of patients (underexposed/within therapeutic range/overexposed) according to AUC or Cmin was concordant in 15 cases. Coadministration of inhibitors was associated with a trend to higher drug exposure, whereas 3 patients treated with levothyroxine showed exceedingly low drug exposure (AUC ∼60 mg*h/L, Cmin <0.4 mg/L). The median unbound fraction in all 20 patients was 90.9%. Drug exposure after standard doses of linezolid is highly variable and difficult to predict in ICU patients, and therapeutic drug monitoring seems advisable. PK drug-drug interactions might partly be responsible and should be further investigated; protein binding appears to be stable and irrelevant.

Speciation of the Bioaccessible Fraction of Arsenic in Rice using IC-ICP-MS

EPA Science Inventory

Dietary arsenic exposure occurs mainly through drinking water and food; therefore, both aspects should be incorporated into any aggregate exposure assessment. Drinking water exposures are predominantly inorganic arsenic (AsIng) while dietary exposures are made up of a diverse se...

An Investigation of Bioaccessibility of Arsenic in Rice using IC-ICP-MS

EPA Science Inventory

Arsenic exposure occurs mainly through drinking water and food; therefore, both aspects should be incorporated into any aggregate exposure assessment. Drinking water exposures are predominately inorganic arsenic while dietary exposures are made up of a diverse set of arsenicals w...

Social exposure and emotion dysregulation: Main effects in relation to nonsuicidal self-injury.

PubMed

Zelkowitz, Rachel L; Porter, Andrew C; Heiman, Ellen R; Cole, David A

2017-10-01

We examined the relation of interpersonal and media exposure to nonsuicidal self-injury (NSSI) among 340 university students in the southeastern United States (73.5% female, M age = 19.38 years, SD = 1.15). We also assessed interactions and main effects of each exposure and emotion dysregulation in relation to NSSI, testing the social learning hypothesis of NSSI. Most participants endorsed medium to high levels of exposure to NSSI via media sources. More than one-third of participants were somewhat or very familiar with someone who engaged in NSSI. Almost half reported occasional or frequent conversations about NSSI. Both exposure forms were significantly related to NSSI history. However, hurdle regression analyses revealed that interpersonal exposure and emotion dysregulation, but not media exposure, were significantly associated with NSSI history and frequency. We did not find evidence for an emotion dysregulation-by-interpersonal-exposure interaction. We discuss implications for theoretical models of NSSI, limitations, and future directions. Copyright © 2017. Published by Elsevier Ltd.

Effects of constant and cyclical thermal regimes on growth and feeding of juvenile cutthroat trout of variable sizes

USGS Publications Warehouse

Meeuwig, M.H.; Dunham, J.B.; Hayes, J.P.; Vinyard, G.L.

2004-01-01

The effects of constant (12, 18, and 24 A?C) and cyclical (daily variation of 15a??21 and 12a??24 A?C) thermal regimes on the growth and feeding of Lahontan cutthroat trout (Oncorhynchus clarki henshawi) of variable sizes were examined. Higher constant temperatures (i.e., 24 A?C) and more variable daily temperatures (i.e., 12a??24 A?C daily cycle) negatively affected growth rates. As fish mass increased (from 0.24 to 15.52 g) the effects of different thermal regimes on mass growth became more pronounced. Following 14 days exposure to the thermal regimes, feeding rates of individual fish were assessed during acute exposure (40 min) to test temperatures of 12, 18, and 24 A?C. Feeding rate was depressed during acute exposure to 24 A?C, but was not significantly affected by the preceding thermal regime. Our results indicate that even brief daily exposure to higher temperatures (e.g., 24 A?C) can have considerable sublethal effects on cutthroat trout, and that fish size should be considered when examining the effects of temperature.

Social network media exposure and adolescent eating pathology in Fiji

PubMed Central

Becker, Anne E.; Fay, Kristen E.; Agnew-Blais, Jessica; Khan, A. Nisha; Striegel-Moore, Ruth H.; Gilman, Stephen E.

2011-01-01

Background Mass media exposure has been associated with an increased risk of eating pathology. It is unknown whether indirect media exposure – such as the proliferation of media exposure in an individual’s social network – is also associated with eating disorders. Aims To test hypotheses that both individual (direct) and social network (indirect) mass media exposures were associated with eating pathology in Fiji. Method We assessed several kinds of mass media exposure, media influence, cultural orientation and eating pathology by self-report among adolescent female ethnic Fijians (n = 523). We fitted a series of multiple regression models of eating pathology, assessed by the Eating Disorder Examination Questionnaire (EDE–Q), in which mass media exposures, sociodemographic characteristics and body mass index were entered as predictors. Results Both direct and indirect mass media exposures were associated with eating pathology in unadjusted analyses, whereas in adjusted analyses only social network media exposure was associated with eating pathology. This result was similar when eating pathology was operationalised as either a continuous or a categorical dependent variable (e.g. odds ratio OR = 1.60, 95% CI 1.15–2.23 relating social network media exposure to upper-quartile EDE–Q scores). Subsequent analyses pointed to individual media influence as an important explanatory variable in this association. Conclusions Social network media exposure was associated with eating pathology in this Fijian study sample, independent of direct media exposure and other cultural exposures. Findings warrant further investigation of its health impact in other populations. PMID:21200076

Social network media exposure and adolescent eating pathology in Fiji.

PubMed

Becker, Anne E; Fay, Kristen E; Agnew-Blais, Jessica; Khan, A Nisha; Striegel-Moore, Ruth H; Gilman, Stephen E

2011-01-01

Mass media exposure has been associated with an increased risk of eating pathology. It is unknown whether indirect media exposure--such as the proliferation of media exposure in an individual's social network--is also associated with eating disorders. To test hypotheses that both individual (direct) and social network (indirect) mass media exposures were associated with eating pathology in Fiji. We assessed several kinds of mass media exposure, media influence, cultural orientation and eating pathology by self-report among adolescent female ethnic Fijians (n=523). We fitted a series of multiple regression models of eating pathology, assessed by the Eating Disorder Examination Questionnaire (EDE-Q), in which mass media exposures, sociodemographic characteristics and body mass index were entered as predictors. Both direct and indirect mass media exposures were associated with eating pathology in unadjusted analyses, whereas in adjusted analyses only social network media exposure was associated with eating pathology. This result was similar when eating pathology was operationalised as either a continuous or a categorical dependent variable (e.g. odds ratio OR=1.60, 95% CI 1.15-2.23 relating social network media exposure to upper-quartile EDE-Q scores). Subsequent analyses pointed to individual media influence as an important explanatory variable in this association. Social network media exposure was associated with eating pathology in this Fijian study sample, independent of direct media exposure and other cultural exposures. Findings warrant further investigation of its health impact in other populations.

Visual Inspection of Surfaces

NASA Technical Reports Server (NTRS)

Hughes, David; Perez, Xavier

2007-01-01

This presentation evaluates the parameters that affect visual inspection of cleanliness. Factors tested include surface reflectance, surface roughness, size of the largest particle, exposure time, inspector and distance from sample surface. It is concluded that distance predictions were not great, particularly because the distance at which contamination is seen may depend on more variables than those tested. Most parameters estimates had confidence of 95% or better, except for exposure and reflectance. Additionally, the distance at which surface is visibly contaminated decreases with increasing reflectance, roughness, and exposure. The distance at which the surface is visually contaminated increased with the largest particle size. These variables were only slightly affected the observer.

Exacerbation of noise-induced hearing loss by co-exposure to workplace chemicals.

PubMed

Sliwinska-Kowalska, Mariola; Zamyslowska-Szmytke, Ewa; Szymczak, Wieslaw; Kotylo, Piotr; Fiszer, Marta; Wesolowski, Wiktor; Pawlaczyk-Luszczynska, Malgorzata

2005-05-01

: Numerous organic solvents applied in industry, like toluene, styrene, xylene and n-hexane have been demonstrated to impair hearing in animals. However, the effects of exposure to a given organic solvent and the interaction of noise and solvents on hearing in humans are still not fully recognized. : The study was aimed to assess the effects of occupational exposure to solvents alone or in combination with noise on hearing in 1117 employees of yacht, ship, plastic, shoe, and paint and lacquer industry. These persons were exposed either to the mixture of organic solvents with xylene as the main component, or predominantly to styrene, or to the mixture of n-hexane and toluene. Detailed questionnaire data and pure-tone audiometry were compared with data of the reference group that included white collar workers, exposed neither to solvents nor noise and metal factory workers exposed to noise only. In all statistics, the confounding factors were recognized as gender, age, exposure to noise, and other variables occurring at a different rate in study and reference group. : Odds ratio (OR) of hearing loss related with the particular exposure to chemicals was 2.4 (95%CI 1.59-3.74) in case of solvent mixture, 3.9 (95%CI 2.4-6.2) in case of styrene and 5.3 (95%CI 2.6-10.9) in case of n-hexane and toluene exposure. The odds of developing hearing loss substantially increased in the case of combined exposure to organic solvents and noise as compared to isolated exposure to each of these hazards. The highest OR (over 20-fold) was demonstrated in subgroups of subjects exposed simultaneously to noise and two ototoxic solvents (i.e. styrene and toluene or n-hexane and toluene). The mean hearing thresholds were significantly higher in the solvent-exposed groups than in the reference group. The differences in thresholds were observed at high frequencies in the solvent mixture- and n-hexane + toluene-exposed groups and at all frequencies in the styrene-exposed group. A positive linear relationship existed between exposure to solvents and hearing thresholds at high frequencies. : The results of the study provide the epidemiological evidence that exposure to organic solvents in humans is associated with an increased risk of hearing loss. The simultaneous exposure to organic solvents and noise seems to enhance the hearing deficit if compared with isolated exposures.

Establishing Long-Term Efficacy in Chronic Disease: Use of Recursive Partitioning and Propensity Score Adjustment to Estimate Outcome in MS

PubMed Central

Goodin, Douglas S.; Jones, Jason; Li, David; Traboulsee, Anthony; Reder, Anthony T.; Beckmann, Karola; Konieczny, Andreas; Knappertz, Volker

2011-01-01

Context Establishing the long-term benefit of therapy in chronic diseases has been challenging. Long-term studies require non-randomized designs and, thus, are often confounded by biases. For example, although disease-modifying therapy in MS has a convincing benefit on several short-term outcome-measures in randomized trials, its impact on long-term function remains uncertain. Objective Data from the 16-year Long-Term Follow-up study of interferon-beta-1b is used to assess the relationship between drug-exposure and long-term disability in MS patients. Design/Setting To mitigate the bias of outcome-dependent exposure variation in non-randomized long-term studies, drug-exposure was measured as the medication-possession-ratio, adjusted up or down according to multiple different weighting-schemes based on MS severity and MS duration at treatment initiation. A recursive-partitioning algorithm assessed whether exposure (using any weighing scheme) affected long-term outcome. The optimal cut-point that was used to define “high” or “low” exposure-groups was chosen by the algorithm. Subsequent to verification of an exposure-impact that included all predictor variables, the two groups were compared using a weighted propensity-stratified analysis in order to mitigate any treatment-selection bias that may have been present. Finally, multiple sensitivity-analyses were undertaken using different definitions of long-term outcome and different assumptions about the data. Main Outcome Measure Long-Term Disability. Results In these analyses, the same weighting-scheme was consistently selected by the recursive-partitioning algorithm. This scheme reduced (down-weighted) the effectiveness of drug exposure as either disease duration or disability at treatment-onset increased. Applying this scheme and using propensity-stratification to further mitigate bias, high-exposure had a consistently better clinical outcome compared to low-exposure (Cox proportional hazard ratio = 0.30–0.42; p<0.0001). Conclusions Early initiation and sustained use of interferon-beta-1b has a beneficial impact on long-term outcome in MS. Our analysis strategy provides a methodological framework for bias-mitigation in the analysis of non-randomized clinical data. Trial Registration Clinicaltrials.gov NCT00206635 PMID:22140424

Temporal and spatial variation in pharmaceutical concentrations in an urban river system.

PubMed

Burns, Emily E; Carter, Laura J; Kolpin, Dana W; Thomas-Oates, Jane; Boxall, Alistair B A

2018-06-15

Many studies have quantified pharmaceuticals in the environment, few however, have incorporated detailed temporal and spatial variability due to associated costs in terms of time and materials. Here, we target 33 physico-chemically diverse pharmaceuticals in a spatiotemporal exposure study into the occurrence of pharmaceuticals in the wastewater system and the Rivers Ouse and Foss (two diverse river systems) in the city of York, UK. Removal rates in two of the WWTPs sampled (a conventional activated sludge (CAS) and trickling filter plant) ranged from not eliminated (carbamazepine) to >99% (paracetamol). Data comparisons indicate that pharmaceutical exposures in river systems are highly variable regionally, in part due to variability in prescribing practices, hydrology, wastewater management, and urbanisation and that select annual median pharmaceutical concentrations observed in this study were higher than those previously observed in the European Union and Asia thus far. Significant spatial variability was found between all sites in both river systems, while seasonal variability was significant for 86% and 50% of compounds in the River Foss and Ouse, respectively. Seasonal variations in flow, in-stream attenuation, usage and septic effluent releases are suspected drivers behind some of the observed temporal exposure variability. When the data were used to evaluate a simple environmental exposure model for pharmaceuticals, mean ratios of predicted environmental concentrations (PECs), obtained using the model, to measured environmental concentrations (MECs) were 0.51 and 0.04 for the River Foss and River Ouse, respectively. Such PEC/MEC ratios indicate that the model underestimates actual concentrations in both river systems, but to a much greater extent in the larger River Ouse. Copyright © 2018 Elsevier Ltd. All rights reserved.

Associations between long-term exposure to chemical constituents of fine particulate matter (PM2.5) and mortality in Medicare enrollees in the eastern United States.

PubMed

Chung, Yeonseung; Dominici, Francesca; Wang, Yun; Coull, Brent A; Bell, Michelle L

2015-05-01

Several epidemiological studies have reported that long-term exposure to fine particulate matter (PM2.5) is associated with higher mortality. Evidence regarding contributions of PM2.5 constituents is inconclusive. We assembled a data set of 12.5 million Medicare enrollees (≥ 65 years of age) to determine which PM2.5 constituents are a) associated with mortality controlling for previous-year PM2.5 total mass (main effect); and b) elevated in locations exhibiting stronger associations between previous-year PM2.5 and mortality (effect modification). For 518 PM2.5 monitoring locations (eastern United States, 2000-2006), we calculated monthly mortality rates, monthly long-term (previous 1-year average) PM2.5, and 7-year averages (2000-2006) of major PM2.5 constituents [elemental carbon (EC), organic carbon matter (OCM), sulfate (SO42-), silicon (Si), nitrate (NO3-), and sodium (Na)] and community-level variables. We applied a Bayesian hierarchical model to estimate location-specific mortality rates associated with previous-year PM2.5 (model level 1) and identify constituents that contributed to the spatial variability of mortality, and constituents that modified associations between previous-year PM2.5 and mortality (model level 2), controlling for community-level confounders. One-standard deviation (SD) increases in 7-year average EC, Si, and NO3- concentrations were associated with 1.3% [95% posterior interval (PI): 0.3, 2.2], 1.4% (95% PI: 0.6, 2.4), and 1.2% (95% PI: 0.4, 2.1) increases in monthly mortality, controlling for previous-year PM2.5. Associations between previous-year PM2.5 and mortality were stronger in combination with 1-SD increases in SO42- and Na. Long-term exposures to PM2.5 and several constituents were associated with mortality in the elderly population of the eastern United States. Moreover, some constituents increased the association between long-term exposure to PM2.5 and mortality. These results provide new evidence that chemical composition can partly explain the differential toxicity of PM2.5.

The conjoint influence of home enriched environment and lead exposure on children's cognition and behaviour in a Mexican lead smelter community.

PubMed

Moodie, Sue; Ialongo, Nick; López, Patricia; Rosado, Jorge; García-Vargas, Gonzalo; Ronquillo, Dolores; Kordas, Katarzyna

2013-01-01

A range of studies has been conducted on the detrimental effects of lead in mining and smelting communities. The neurocognitive and behavioural health effects of lead on children are well known. This research characterized the conjoint influence of lead exposure and home enriched environment on neurocognitive function and behaviour for first-grade children living in a Mexican lead smelter community. Structural equation models were used for this analysis with latent outcome variables, Cognition and Behaviour, constructed based on a battery of assessments administered to the first-grade children, their parents, and teachers. Structural equation modelling was used to describe complex relationships of exposure and health outcomes in a manner that permitted partition of both direct and indirect effects of the factors being measured. Home Environment (a latent variable constructed from information on mother's education and support of school work and extracurricular activities), and child blood lead concentration each had a main significant effect on cognition and behaviour. However, there were no statistically significant moderation relationships between lead and Home Environment on these latent outcomes. Home Environment had a significant indirect mediation effect between lead and both Cognition and Behaviour (p-value<0.001). The mediation model had a good fit with Root Mean Square Error of Approximation <0.0001 and a Weighted Root Mean Square Residual of 0.895. These results were highly significant and suggest that Home Environment has a moderate mediation effect with respect to lead effects on Behaviour (β=0.305) and a lower mediation effect on Cognition (β=0.184). The extent of home enrichment in this study was most highly related to the mother's support of schoolwork and slightly less by the mother's support of extracurricular activities or mother's education. Further research may be able to develop approaches to support families to make changes within their home and child rearing practices, or advocate for different approaches to support their child's behaviour to reduce the impact of lead exposure on children's cognitive and behavioural outcomes. Copyright © 2012 Elsevier Inc. All rights reserved.

Effects of Variable Spot Size on Human Exposure to 95 GHz Millimeter Wave Energy

DTIC Science & Technology

2017-05-11

AFRL -RH-FS-TR-2017-0017 Effects of Variable Spot Size on Human Exposure to 95-GHz Millimeter Wave Energy James E. Parker Eric J. Nelson...Defense Technical Information Center (DTIC) (http://www.dtic.mil). ( AFRL -RH-FS- - - ) has been reviewed and is approved for publication in accordance with...REPORT NUMBER(S) AFRL -RH-FS-TR-2017-0017 12. DISTRIBUTION / AVAILABILITY STATEMENT Distribution A: Approved for public release; distribution

Do Differences in Exposures Explain the Observed Heterogeneity in PM2.5 - Mortality Associations across U.S. cities?

EPA Science Inventory

This analysis evaluates exposure factors as potential determinants of the heterogeneity in city-specific associations between PM2.5 and mortality. Exposure factor variables were created based on housing characteristics, commuting patterns, heating fuel usage, and climatic factors...

ANALYZE EXISTING DATA ON PM COMPOSITION TO IDENTIFY KEY FACTORS WHICH INFLUENCE HUMAN EXPOSURES TO PM CONSTITUENTS

EPA Science Inventory

An association has been demonstrated between ambient particulate matter (PM 2.5 and PM 10) concentrations and human morbidity/mortality. However, little is known regarding the most important sources of PM exposure, interpersonal and intrapersonal variability in exposure, and the...

Development and Evaluation of a New Air Exchange Rate Algorithm for the Stochastic Human Exposure and Dose Simulation Model (ISES Presentation)

EPA Science Inventory

Previous exposure assessment panel studies have observed considerable seasonal, between-home and between-city variability in residential pollutant infiltration. This is likely a result of differences in home ventilation, or air exchange rates (AER). The Stochastic Human Exposure ...

Transient receptor potential cation channel A1 (TRPA1) mediates changes in heart rate variability following a single exposure to acrolein in mice

EPA Science Inventory

The data show that a single exposure to acrolein causes autonomic imbalance in mice through the TRPA1 sensor and subsequent cardiac dysfunction. Human and animal studies have shown that short-term air pollution exposure causes...

A META-ANALYSIS OF CHILDREN'S HAND-TO-MOUTH FREQUENCY DATA FOR ESTIMATING NON-DIETARY INGESTION EXPOSURE

EPA Science Inventory

Because of their mouthing behaviors, children have a higher potential for exposure to available chemicals through the non-dietary ingestion route; thus, frequency of hand-to-mouth activity is an important variable for exposure assessments. Such data are limited and difficult to ...

Cumulative Estrogen Exposure and Prospective Memory in Older Women

ERIC Educational Resources Information Center

Hesson, Jacqueline

2012-01-01

This study looked at cumulative lifetime estrogen exposure, as estimated with a mathematical index (Index of Cumulative Estrogen Exposure (ICEE)) that included variables (length of time on estrogen therapy, age at menarche and menopause, postmenopausal body mass index, time since menopause, nulliparity and duration of breastfeeding) known to…

Variations in brain defects result from cellular mosaicism in the activation of heat shock signalling.

PubMed

Ishii, Seiji; Torii, Masaaki; Son, Alexander I; Rajendraprasad, Meenu; Morozov, Yury M; Kawasawa, Yuka Imamura; Salzberg, Anna C; Fujimoto, Mitsuaki; Brennand, Kristen; Nakai, Akira; Mezger, Valerie; Gage, Fred H; Rakic, Pasko; Hashimoto-Torii, Kazue

2017-05-02

Repetitive prenatal exposure to identical or similar doses of harmful agents results in highly variable and unpredictable negative effects on fetal brain development ranging in severity from high to little or none. However, the molecular and cellular basis of this variability is not well understood. This study reports that exposure of mouse and human embryonic brain tissues to equal doses of harmful chemicals, such as ethanol, activates the primary stress response transcription factor heat shock factor 1 (Hsf1) in a highly variable and stochastic manner. While Hsf1 is essential for protecting the embryonic brain from environmental stress, excessive activation impairs critical developmental events such as neuronal migration. Our results suggest that mosaic activation of Hsf1 within the embryonic brain in response to prenatal environmental stress exposure may contribute to the resulting generation of phenotypic variations observed in complex congenital brain disorders.

Without Warning: Worker Deaths From Heat 2014-2016.

PubMed

Roelofs, Cora

2018-01-01

Worker deaths from heat exposure are unlike heat deaths in the general population; workers tend to be outside in variable temperatures and younger than sixty-five years. Climate change will increase the frequency, duration, and variability of hot temperatures. Public health warning systems, such as the Heat Index of the National Weather Service, do not generally account for workers' greater likelihood of exposure to direct sunlight or exertion. Only 28% of the 79 worker heat-related fatalities during 2014-2016 occurred on days when the National Weather Service warning would have included the possibility of fatal heat stroke. Common heat illness prevention advice ignores workers' lack of control over their ability to rest and seek cooler temperatures. Additionally, acclimatization, or phased-in work in the heat, may be less useful given temperature variability under climate change. Workers' vulnerability and context of heat exposure should inform public health surveillance and response to prevent heat illness and death.

Individual signatures and environmental factors shape skin microbiota in healthy dogs.

PubMed

Cuscó, Anna; Belanger, Janelle M; Gershony, Liza; Islas-Trejo, Alma; Levy, Kerinne; Medrano, Juan F; Sánchez, Armand; Oberbauer, Anita M; Francino, Olga

2017-10-13

The individual, together with its environment, has been reported as the main force driving composition and structure of skin microbiota in healthy dogs. Therefore, one of the major concerns when analyzing canine skin microbiota is the likely influence of the environment. Despite the dense fur covering, certain skin diseases exhibit differential prevalence among skin sites, dog breeds, and individuals. We have characterized the normal variability of dog skin microbiota in a well-controlled cohort of a large number of Golden-Labrador Retriever crossed dogs (N = 35) with similar ages, related genetic background, and a shared environment. We found that the individual drives the skin microbiota composition and structure followed by the skin site. The main bacterial classes inhabiting dog skin in this cohort are Gammaproteobacteria and Bacilli. We also detected bacteria associated to the environment on different dog skin sites that could be reflecting the different degrees of exposure of each skin site and each dog. Network analyses elucidated bacterial interactions within and between skin sites, especially in the chin, abdomen, axilla, and perianal region, with the highly shared interactions probably representing an anatomical, behavioral, or environmental component. When analyzing each skin site independently to assess host-specific factors, we found that temporality (season of birth and time spent in the kennel) affected all the skin sites and specially the inner pinna. The most abundant taxon driving this difference was Sphingomonas. We also found taxonomic differences among male and female dogs on the abdomen, axilla, and back. We observed a large inter-individual variability and differences among skin sites. Host-specific variables, such as temporality or sex, were also shaping skin microbiota of healthy dogs, even in an environmental homogenous cohort.

[Criteria for assessing severely hot environments: from the WBGT index to the PHS (predicted heat strain) model].

PubMed

d'Ambrosio, Francesca Romana; Palella, B I; Riccio, G; Alfano, G

2004-01-01

The present study deals with the main methods for assessment of hot environments: i.e., WBGT, SWreq and PHS. It is stressed how the WBGT index, which is strictly empirical, although a very practical tool for the assessment of the hot environments, can only be used for a rough evaluation of heat stress, and especially for a not very high metabolic rate (M<175 W/m2). On the contrary, the SWreq method, which is based on both subject-environment heat exchange and the effect of clothing, allows a better assessment of the work situation with a general reduction of the exposure limits with respect to WBGT, especially in non-uniform environments (ta not equal to tr). However, it should be noted that application of SWreq is required by the ISO standard 7243 when the WBGT limit values are exceeded. In this study interest was extensively focused on the "Predicted Heat Strain" method, highlighting via a special software the differences in heat stress assessment related to this new approach, which will be adopted by the ISO in the next revision of standard 7933. The PHS method, unlike SWreq, allows the prediction of the time-response of the main physiological variables of interest (i.e., skin temperature, core temperature and sweat rate). Moreover thanks to better modelling of heat exchanges, the PHS method allows account to be taken of both movement and clothing effects, resulting in even more reduced exposure.

Post-heading heat stress and yield impact in winter wheat of China.

PubMed

Liu, Bing; Liu, Leilei; Tian, Liying; Cao, Weixing; Zhu, Yan; Asseng, Senthold

2014-02-01

Wheat is sensitive to high temperatures, but the spatial and temporal variability of high temperature and its impact on yield are often not known. An analysis of historical climate and yield data was undertaken to characterize the spatial and temporal variability of heat stress between heading and maturity and its impact on wheat grain yield in China. Several heat stress indices were developed to quantify heat intensity, frequency, and duration between heading and maturity based on measured maximum temperature records of the last 50 years from 166 stations in the main wheat-growing region of China. Surprisingly, heat stress between heading and maturity was more severe in the generally cooler northern wheat-growing regions than the generally warmer southern regions of China, because of the delayed time of heading with low temperatures during the earlier growing season and the exposure of the post-heading phase into the warmer part of the year. Heat stress between heading and maturity has increased in the last decades in most of the main winter wheat production areas of China, but the rate was higher in the south than in the north. The correlation between measured grain yields and post-heading heat stress and average temperature were statistically significant in the entire wheat-producing region, and explained about 29% of the observed spatial and temporal yield variability. A heat stress index considering the duration and intensity of heat between heading and maturity was required to describe the correlation of heat stress and yield variability. Because heat stress is a major cause of yield loss and the number of heat events is projected to increase in the future, quantifying the future impact of heat stress on wheat production and developing appropriate adaptation and mitigation strategies are critical for developing food security policies in China and elsewhere. © 2013 John Wiley & Sons Ltd.

Evaluation of polyurethane foam passive air sampler (PUF) as a tool for occupational PAH measurements.

PubMed

Strandberg, Bo; Julander, Anneli; Sjöström, Mattias; Lewné, Marie; Koca Akdeva, Hatice; Bigert, Carolina

2018-01-01

Routine monitoring of workplace exposure to polycyclic aromatic hydrocarbons (PAHs) is performed mainly via active sampling. However, active samplers have several drawbacks and, in some cases, may even be unusable. Polyurethane foam (PUF) as personal passive air samplers constitute good alternatives for PAH monitoring in occupational air (8 h). However, PUFs must be further tested to reliably yield detectable levels of PAHs in short exposure times (1-3 h) and under extreme occupational conditions. Therefore, we compared the personal exposure monitoring performance of a passive PUF sampler with that of an active air sampler and determined the corresponding uptake rates (Rs). These rates were then used to estimate the occupational exposure of firefighters and police forensic specialists to 32 PAHs. The work environments studied were heavily contaminated by PAHs with (for example) benzo(a)pyrene ranging from 0.2 to 56 ng m -3 , as measured via active sampling. We show that, even after short exposure times, PUF can reliably accumulate both gaseous and particle-bound PAHs. The Rs-values are almost independent of variables such as the concentration and the wind speed. Therefore, by using the Rs-values (2.0-20 m 3 day -1 ), the air concentrations can be estimated within a factor of two for gaseous PAHs and a factor of 10 for particulate PAHs. With very short sampling times (1 h), our method can serve as a (i) simple and user-friendly semi-quantitative screening tool for estimating and tracking point sources of PAH in micro-environments and (ii) complement to the traditional active pumping methods. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Using a chemistry transport model to account for the spatial variability of exposure concentrations in epidemiologic air pollution studies.

PubMed

Valari, Myrto; Menut, Laurent; Chatignoux, Edouard

2011-02-01

Environmental epidemiology and more specifically time-series analysis have traditionally used area-averaged pollutant concentrations measured at central monitors as exposure surrogates to associate health outcomes with air pollution. However, spatial aggregation has been shown to contribute to the overall bias in the estimation of the exposure-response functions. This paper presents the benefit of adding features of the spatial variability of exposure by using concentration fields modeled with a chemistry transport model instead of monitor data and accounting for human activity patterns. On the basis of county-level census data for the city of Paris, France, and a Monte Carlo simulation, a simple activity model was developed accounting for the temporal variability between working and evening hours as well as during transit. By combining activity data with modeled concentrations, the downtown, suburban, and rural spatial patterns in exposure to nitrogen dioxide, ozone, and PM2.5 (particulate matter [PM] < or = 10 microm in aerodynamic diameter) were captured and parametrized. Exposures predicted with this model were used in a time-series study of the short-term effect of air pollution on total nonaccidental mortality for the 4-yr period from 2001 to 2004. It was shown that the time series of the exposure surrogates developed here are less correlated across co-pollutants than in the case of the area-averaged monitor data. This led to less biased exposure-response functions when all three co-pollutants were inserted simultaneously in the same regression model. This finding yields insight into pollutant-specific health effects that are otherwise masked by the high correlation among co-pollutants.

Exposure to Fentanyl After Transdermal Patch Administration for Cancer Pain Management.

PubMed

Bista, Sudeep R; Haywood, Alison; Hardy, Janet; Norris, Ross; Hennig, Stefanie

2016-06-01

This study aimed to describe exposure after fentanyl transdermal patch administration in patients with advanced cancer to quantify variability around the exposure. Patients (n  =  56) with advanced cancer who received transdermal fentanyl (Durogesic®; median dose, 50 μg/h; range, 12-200 μg/h) provided venous blood samples (n  =  163) at various times (0.5-72 hours) during several patch application intervals. Plasma fentanyl concentration was determined (median, 0.9 μg/L; range, 0.04-9.7 μg/L) by high-performance liquid chromatography coupled to tandem mass spectrometry. Pharmacokinetic analysis was performed using nonlinear mixed-effects modeling with NONMEM. A 1-compartment distribution model with first-order absorption and elimination described fentanyl exposure after transdermal patch administration. Fentanyl apparent clearance (between-subject variability [BSV], %) was estimated at 122 L/h/70 kg and 38.5%, respectively. The absorption rate constant was 0.013 h(-1) . Between-occasion variability on apparent clearance was 22.0%, which was lower than BSV, suggesting predictable exposure within the same patient and justifying therapeutic drug monitoring. Except for weight-based dosing, no other patient characteristic could be identified to guide initial fentanyl dose selection in patients with advanced cancer. © 2015, The American College of Clinical Pharmacology.

Risk assessment of drought disaster in southern China

NASA Astrophysics Data System (ADS)

Wang, Y.

2015-12-01

Abstract: Drought has become an increasing concern in southern China, but the drought risk has not been adequately studied. This study presents a method for the spatial assessment of drought risk in southern China using a conceptual framework that emphasizes the combined role of hazard, vulnerability, and exposure.A drought hazard map was retrieved with a compound index of meteorological drought method in a GIS environment. Normally, a large variation in the disaster-inducing factor implies a high probability of economic/social losses caused by a drought disaster. The map indicated that areas with a higher risk of drought hazard were mainly distributed in mid-east Yunnan and the basins in eastern Sichuan.The vulnerability indices were based on climate factors as well as land use, geomorphological types, soil properties, and drainage density. The water preserving capability of purple calcareous soil in the basins in Sichuan and mid-east Yunnan, and the lateritic red soil in northeastern Guangdong is relatively weak. The main geomorphological features in Guangxi and Guangdong are hills, which leads to a serious expectation of soil and water losses. Thus, the main areas with a high risk of drought vulnerability are mid-east Yunnan and the basins in eastern Sichuan.The exposure indices were based on population density and agricultural production because population and agriculture experience the main impacts of a drought disaster. Higher exposure indices mean higher economic/social losses due to drought disasters. Areas with high exposure indices were mainly distributed in Guangdong and southern Guangxi.The overall risk was then calculated as the product of the hazard, vulnerability, and exposure. The results indicated a higher risk of drought disaster in the basins in eastern Sichuan,, northeastern Yunnan, and northeastern Guangdong. The main factor influencing the risk of a drought disaster was the hazard, but the vulnerability and exposure also played important roles.

Facts about Hypospadias

MedlinePlus

... 1997-2011) and the Birth Defects Study to Evaluate Pregnancy exposureS (BD-STEPS; began with births in ... to 2012: Presentation of state-specific data and descriptive brief on variability of prevalence. Birth Def Res ( ...

Exposure Perception as a Key Indicator of Risk Perception and Acceptance of Sources of Radio Frequency Electromagnetic Fields.

PubMed

Freudenstein, Frederik; Wiedemann, Peter M; Brown, Tim W C

2015-01-01

The presented survey was conducted in six European countries as an online study. A total of 2454 subjects participated. Two main research questions were investigated: firstly, how does the cognitive, moral, and affective framing of radio frequency electromagnetic field (RF EMF) exposure perception influence RF EMF risk perception? Secondly, can the deployment of mobile phone base stations have greater acceptance with RF EMF exposure reduction? The findings with respect to the first question clearly indicated that the cognitive framed exposure perception is the main determinant of RF EMF risk perception. The concomitant sensitivity to exposure strength offers an opportunity to improve the acceptance of base stations by exposure reduction. A linear regression analysis supported this assumption: in a fictional test situation, exposure reduction improved the acceptance of base stations, operationalized as the requested distance of the base station from one's own home. Furthermore, subjects with high RF EMF risk perception were most sensitive to exposure reduction. On average, a 70% exposure reduction reduced the requested distance from about 2000 meters to 1000 meters. The consequences for risk communication are discussed.

Bayesian effect estimation accounting for adjustment uncertainty.

PubMed

Wang, Chi; Parmigiani, Giovanni; Dominici, Francesca

2012-09-01

Model-based estimation of the effect of an exposure on an outcome is generally sensitive to the choice of which confounding factors are included in the model. We propose a new approach, which we call Bayesian adjustment for confounding (BAC), to estimate the effect of an exposure of interest on the outcome, while accounting for the uncertainty in the choice of confounders. Our approach is based on specifying two models: (1) the outcome as a function of the exposure and the potential confounders (the outcome model); and (2) the exposure as a function of the potential confounders (the exposure model). We consider Bayesian variable selection on both models and link the two by introducing a dependence parameter, ω, denoting the prior odds of including a predictor in the outcome model, given that the same predictor is in the exposure model. In the absence of dependence (ω= 1), BAC reduces to traditional Bayesian model averaging (BMA). In simulation studies, we show that BAC, with ω > 1, estimates the exposure effect with smaller bias than traditional BMA, and improved coverage. We, then, compare BAC, a recent approach of Crainiceanu, Dominici, and Parmigiani (2008, Biometrika 95, 635-651), and traditional BMA in a time series data set of hospital admissions, air pollution levels, and weather variables in Nassau, NY for the period 1999-2005. Using each approach, we estimate the short-term effects of on emergency admissions for cardiovascular diseases, accounting for confounding. This application illustrates the potentially significant pitfalls of misusing variable selection methods in the context of adjustment uncertainty. © 2012, The International Biometric Society.

Occupational exposure of electrical utility linemen to pentachlorophenol.

PubMed

Thind, K S; Karmali, S; House, R A

1991-12-01

Occupational exposure to pentachlorophenol (PCP) for a crew of electrical utility linemen was monitored over a 6-month period by using total PCP in urine per gram of creatinine as a biological monitoring parameter. Urine samples were collected from three groups: A, B, and control, at a 4-week frequency during 1989. Group A was required to use new gloves after each 4-week work period; Group B changed gloves on a need basis as per normal operating procedure. The control group consisted of members of the administrative office staff who were not occupationally exposed. The used gloves returned by Group A were monitored for contamination. On the basis of analysis of the collected data the following conclusions were noted. (1) The linemen experienced a seasonal exposure pattern with exposures peaking in July and August. This seasonal effect was also observed with glove contamination data. (2) The glove contamination levels were significantly associated with urine PCP concentrations when both these variables were expressed as geometric means for the individuals in Group A. Inclusion of work experience as an additional variable enhances this association. Less experienced linemen tended to perform more activities with higher current exposure and had higher urine and glove PCP measurements and higher correlations between these variables than more experienced linemen. (3) Over the study period, the difference in long-term exposures of Group A and Group B linemen was not statistically significant. (4) The long-term individual exposures, calculated as the geometric mean of each individual's sequential sample readings, were all below the biological monitoring guideline value of 1000 micrograms PCP/g creatinine.

Chronic toxicity of fumonisins in turkeys.

PubMed

Tardieu, D; Bailly, J-D; Skiba, F; Métayer, J-P; Grosjean, F; Guerre, P

2007-09-01

Fumonisins are mycotoxins that are found worldwide. They are mainly produced by Fusarium verticillioides during its development on corn. The main toxic effects of these molecules have been well characterized in poultry in the case of acute exposure, but the subclinical and economic effects of chronic exposure are less known. Whereas the latest European recommendations suggest that maximal levels of fumonisins in corn could reach 60 mg/kg and the maximal contamination of poultry feeds could reach 20 mg/kg, no study is available at this level in turkeys. The aim of the present work was thus to characterize the effects of exposure to fumonisins (concentrations of 0, 5, 10, and 20 mg of fumonisin B1 + fumonisin B2/kg of feed) on feed consumption and growth in turkeys over a period of 9 wk. Main biochemical parameters of the liver and alteration of sphingolipid metabolism were investigated in plasma, liver, and kidney. The main results showed no effect on feed consumption and growth in exposed turkeys. Moreover, no effect was observed on the weight of tissues and markers of liver injury. By contrast, a disruption of sphingolipid metabolism was clear at a level of exposure of 10 and 20 mg of fumonisin B1 + fumonisin B2 mg/kg of feed. Both hepatic and kidney concentrations of sphinganine increased gradually throughout the exposure period. These results reveal that disruption of sphingolipid metabolism is an early and sensitive biomarker of fumonisins exposure in turkeys; the consequences on these alterations remain to be established.

VOC source identification from personal and residential indoor, outdoor and workplace microenvironment samples in EXPOLIS-Helsinki, Finland

NASA Astrophysics Data System (ADS)

Edwards, Rufus D.; Jurvelin, J.; Koistinen, K.; Saarela, K.; Jantunen, M.

Principal component analyses (varimax rotation) were used to identify common sources of 30 target volatile organic compounds (VOCs) in residential outdoor, residential indoor and workplace microenvironment and personal 48-h exposure samples, as a component of the EXPOLIS-Helsinki study. Variability in VOC concentrations in residential outdoor microenvironments was dominated by compounds associated with long-range transport of pollutants, followed by traffic emissions, emissions from trees and product emissions. Variability in VOC concentrations in environmental tobacco smoke (ETS) free residential indoor environments was dominated by compounds associated with indoor cleaning products, followed by compounds associated with traffic emissions, long-range transport of pollutants and product emissions. Median indoor/outdoor ratios for compounds typically associated with traffic emissions and long-range transport of pollutants exceeded 1, in some cases quite considerably, indicating substantial indoor source contributions. Changes in the median indoor/outdoor ratios during different seasons reflected different seasonal ventilation patterns as increased ventilation led to dilution of those VOC compounds in the indoor environment that had indoor sources. Variability in workplace VOC concentrations was dominated by compounds associated with traffic emissions followed by product emissions, long-range transport and air fresheners. Variability in VOC concentrations in ETS free personal exposure samples was dominated by compounds associated with traffic emissions, followed by long-range transport, cleaning products and product emissions. VOC sources in personal exposure samples reflected the times spent in different microenvironments, and personal exposure samples were not adequately represented by any one microenvironment, demonstrating the need for personal exposure sampling.

Personal exposure to metal fume, NO2, and O3 among production welders and non-welders.

PubMed

Schoonover, Todd; Conroy, Lorraine; Lacey, Steven; Plavka, Julie

2011-01-01

The objective of this study was to characterize personal exposures to welding-related metals and gases for production welders and non-welders in a large manufacturing facility. Welding fume metals and irritant gases nitrogen dioxide (NO(2)) and ozone (O(3)) were sampled for thirty-eight workers. Personal exposure air samples for welding fume metals were collected on 37 mm open face cassettes and nitrogen dioxide and ozone exposure samples were collected with diffusive passive samplers. Samples were analyzed for metals using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and welding fume metal exposure concentrations were defined as the sum of welding-related metals mass per volume of air sampled. Welding fume metal exposures were highly variable among similar types of welding while NO(2) and O(3) exposure were less variable. Welding fume metal exposures were significantly higher 474 μg/m(3) for welders than non-welders 60 μg/m(3) (p=0.001). Welders were exposed to higher concentrations of NO(2) and O(3) than non-welders but the differences were not statistically significant. Welding fume metal exposure concentrations for welders performing gas metal arc welding (GMAW) and shielded metal arc welding (SMAW) were higher than welders performing gas tungsten arc welding (GTAW). Non-welders experienced exposures similar to GTAW welders despite a curtain wall barrier separating welding and non-welding work areas.

Lipid Adjustment for Chemical Exposures: Accounting for Concomitant Variables

PubMed Central

Li, Daniel; Longnecker, Matthew P.; Dunson, David B.

2013-01-01

Background Some environmental chemical exposures are lipophilic and need to be adjusted by serum lipid levels before data analyses. There are currently various strategies that attempt to account for this problem, but all have their drawbacks. To address such concerns, we propose a new method that uses Box-Cox transformations and a simple Bayesian hierarchical model to adjust for lipophilic chemical exposures. Methods We compared our Box-Cox method to existing methods. We ran simulation studies in which increasing levels of lipid-adjusted chemical exposure did and did not increase the odds of having a disease, and we looked at both single-exposure and multiple-exposures cases. We also analyzed an epidemiology dataset that examined the effects of various chemical exposures on the risk of birth defects. Results Compared with existing methods, our Box-Cox method produced unbiased estimates, good coverage, similar power, and lower type-I error rates. This was the case in both single- and multiple-exposure simulation studies. Results from analysis of the birth-defect data differed from results using existing methods. Conclusion Our Box-Cox method is a novel and intuitive way to account for the lipophilic nature of certain chemical exposures. It addresses some of the problems with existing methods, is easily extendable to multiple exposures, and can be used in any analyses that involve concomitant variables. PMID:24051893

Delineation of Spatial Variability in the Temperature-Mortality Relationship on Extremely Hot Days in Greater Vancouver, Canada.

PubMed

Ho, Hung Chak; Knudby, Anders; Walker, Blake Byron; Henderson, Sarah B

2017-01-01

Climate change has increased the frequency and intensity of extremely hot weather. The health risks associated with extemely hot weather are not uniform across affected areas owing to variability in heat exposure and social vulnerability, but these differences are challenging to map with precision. We developed a spatially and temporally stratified case-crossover approach for delineation of areas with higher and lower risks of mortality on extremely hot days and applied this approach in greater Vancouver, Canada. Records of all deaths with an extremely hot day as a case day or a control day were extracted from an administrative vital statistics database spanning the years of 1998-2014. Three heat exposure and 11 social vulnerability variables were assigned at the residential location of each decedent. Conditional logistic regression was used to estimate the odds ratio for a 1°C increase in daily mean temperature at a fixed site with an interaction term for decedents living above and below different values of the spatial variables. The heat exposure and social vulnerability variables with the strongest spatially stratified results were the apparent temperature and the labor nonparticipation rate, respectively. Areas at higher risk had values ≥ 34.4°C for the maximum apparent temperature and ≥ 60% of the population neither employed nor looking for work. These variables were combined in a composite index to quantify their interaction and to enhance visualization of high-risk areas. Our methods provide a data-driven framework for spatial delineation of the temperature--mortality relationship by heat exposure and social vulnerability. The results can be used to map and target the most vulnerable areas for public health intervention. Citation: Ho HC, Knudby A, Walker BB, Henderson SB. 2017. Delineation of spatial variability in the temperature-mortality relationship on extremely hot days in greater Vancouver, Canada. Environ Health Perspect 125:66-75; http://dx.doi.org/10.1289/EHP224.

Delineation of Spatial Variability in the Temperature–Mortality Relationship on Extremely Hot Days in Greater Vancouver, Canada

PubMed Central

Ho, Hung Chak; Knudby, Anders; Walker, Blake Byron; Henderson, Sarah B.

2016-01-01

Background: Climate change has increased the frequency and intensity of extremely hot weather. The health risks associated with extemely hot weather are not uniform across affected areas owing to variability in heat exposure and social vulnerability, but these differences are challenging to map with precision. Objectives: We developed a spatially and temporally stratified case-crossover approach for delineation of areas with higher and lower risks of mortality on extremely hot days and applied this approach in greater Vancouver, Canada. Methods: Records of all deaths with an extremely hot day as a case day or a control day were extracted from an administrative vital statistics database spanning the years of 1998–2014. Three heat exposure and 11 social vulnerability variables were assigned at the residential location of each decedent. Conditional logistic regression was used to estimate the odds ratio for a 1°C increase in daily mean temperature at a fixed site with an interaction term for decedents living above and below different values of the spatial variables. Results: The heat exposure and social vulnerability variables with the strongest spatially stratified results were the apparent temperature and the labor nonparticipation rate, respectively. Areas at higher risk had values ≥ 34.4°C for the maximum apparent temperature and ≥ 60% of the population neither employed nor looking for work. These variables were combined in a composite index to quantify their interaction and to enhance visualization of high-risk areas. Conclusions: Our methods provide a data-driven framework for spatial delineation of the temperature-–mortality relationship by heat exposure and social vulnerability. The results can be used to map and target the most vulnerable areas for public health intervention. Citation: Ho HC, Knudby A, Walker BB, Henderson SB. 2017. Delineation of spatial variability in the temperature–mortality relationship on extremely hot days in greater Vancouver, Canada. Environ Health Perspect 125:66–75; http://dx.doi.org/10.1289/EHP224 PMID:27346526

Polycyclic Aromatic Hydrocarbons in Residential Dust: Sources of Variability

PubMed Central

Metayer, Catherine; Petreas, Myrto; Does, Monique; Buffler, Patricia A.; Rappaport, Stephen M.

2013-01-01

Background: There is interest in using residential dust to estimate human exposure to environmental contaminants. Objectives: We aimed to characterize the sources of variability for polycyclic aromatic hydrocarbons (PAHs) in residential dust and provide guidance for investigators who plan to use residential dust to assess exposure to PAHs. Methods: We collected repeat dust samples from 293 households in the Northern California Childhood Leukemia Study during two sampling rounds (from 2001 through 2007 and during 2010) using household vacuum cleaners, and measured 12 PAHs using gas chromatography–mass spectrometry. We used a random- and a mixed-effects model for each PAH to apportion observed variance into four components and to identify sources of variability. Results: Median concentrations for individual PAHs ranged from 10 to 190 ng/g of dust. For each PAH, total variance was apportioned into regional variability (1–9%), intraregional between-household variability (24–48%), within-household variability over time (41–57%), and within-sample analytical variability (2–33%). Regional differences in PAH dust levels were associated with estimated ambient air concentrations of PAH. Intraregional differences between households were associated with the residential construction date and the smoking habits of residents. For some PAHs, a decreasing time trend explained a modest fraction of the within-household variability; however, most of the within-household variability was unaccounted for by our mixed-effects models. Within-household differences between sampling rounds were largest when the interval between dust sample collections was at least 6 years in duration. Conclusions: Our findings indicate that it may be feasible to use residential dust for retrospective assessment of PAH exposures in studies of health effects. PMID:23461863

Antibiotics detected in urines and adipogenesis in school children.

PubMed

Wang, Hexing; Wang, Na; Wang, Bin; Fang, Hong; Fu, Chaowei; Tang, Chuanxi; Jiang, Feng; Zhou, Ying; He, Gengsheng; Zhao, Qi; Chen, Yue; Jiang, Qingwu

2016-01-01

Although antibiotic use during early life has been demonstrated to be related to the altered adipogenesis in later life, limited data are available for the effect of antibiotic exposure in school children on adiposity from various sources, including from the use or contaminated food or drinking water. To explore the association between the internal exposure of antibiotics from various sources and adipogenesis in school children using the biomonitoring of urinary antibiotics. After 586 school children aged 8-11years were selected from Shanghai in 2013, total urinary concentrations (free and conjugated) of 21 common antibiotics from six categories (macrolides, β-lactams, tetracyclines, fluoroquinolones, sulfonamides, and phenicols), including five human antibiotics (HAs), two antibiotics preferred as HA, four veterinary antibiotics (VAs), and ten antibiotics preferred as VA, were measured by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. Creatinine-corrected urinary concentrations of antibiotics were used to assess their exposure. Overweight or obesity was determined by the body mass index or waist circumference-based criteria deriving from national data. All 21 antibiotics were found in urines with the overall detection frequency of 79.6%. The multinomial logistic regression analyses showed the significant associations of overweight and obesity with the exposure to VAs and antibiotics preferred as VA, but not with HAs or antibiotics preferred as HA. After adjusted for a number of obesity-relevant variables, the odds ratios (95% confidence interval) of BMI-based obesity risk of tertiles 2 and 3 of urinary concentrations relative to tertile 1 were respectively 2.54 (1.27, 5.07) and 2.92 (1.45, 5.87) for florfenicol, 0.57 (0.12, 2.63) and 3.63 (1.41, 9.32) for trimethoprim, and 3.00 (1.56, 5.76) and 1.99 (0.99, 4.01) for sum of veterinary antibiotics. Similar results were found when the outcome used WC-based obesity risk. The associations were sex related and mainly observed in boys. Some types of antibiotic exposure, which were mainly from food or drinking water, were associated with an increased risk of obesity in school children. Due to the cross-sectional design, more longitudinal and experimental studies are warranted to further test these findings. Copyright © 2016. Published by Elsevier Ltd.

Response of Urban Systems to Climate Change in Europe: Heat Stress Exposure and the Effect on Human Health

NASA Astrophysics Data System (ADS)

Stevens, Catherine; Thomas, Bart; Grommen, Mart

2015-04-01

Climate change is driven by global processes such as the global ocean circulation and its variability over time leading to changing weather patterns on regional scales as well as changes in the severity and occurrence of extreme events such as heavy rain- and windstorms, floods, drought, heat waves, etc. The summer 2003 European heat wave was the hottest summer on record in Europe over the past centuries leading to health crises in several countries like France and caused up to 70.000 excess deaths over four months in Central and Western Europe. The main risks induced by global climate change in urbanised areas are considered to be overheating and resulting health effects, increased exposure to flood events, increased damage losses from extreme weather conditions but also shortages in the provision of life-sustaining services. Moreover, the cities themselves create specific or inherent risks and urban adaptation is often very demanding. As most of Europe's inhabitants live in cities, it is of particular relevance to examine the impact of climate variability on urban areas and their populations. The present study focusses on the identification of heat stress variables related to human health and the extraction of this information by processing daily temperature statistics of local urban climate simulations over multiple timeframes of 20 years and three different European cities based on recent, near future and far future global climate predictions. The analyses have been conducted in the framework of the NACLIM FP7 project funded by the European Commission involving local stakeholders such as the cities of Antwerp (Belgium), Berlin (Germany) and Almada (Portugal) represented by different climate and urban characteristics. Apart from the urban-rural temperature increment (urban heat island effect), additional heat stress parameters such as the average number of heat wave days together with their duration and intensities have been covered during this research. In a subsequent step, the heat stress variables are superposed on relevant socio-economic datasets targeting total population and its distribution per age class as well as vulnerable institutions such as hospitals, schools, rest homes and child/day care facilities in order to generate heat stress exposure maps for each use case city and various climate, urban planning and mitigation scenarios. The specifications and requirements for the various scenarios have been consolidated in close collaboration with the local stakeholders during dedicated end-users workshops. The results of this study will allow urban planners and policy makers facing the challenges of climate change and develop sound strategies for evolving towards sustainable and climate resilient cities.

Does early-life family income influence later dental pain experience? A prospective 14-year study.

PubMed

Ghorbani, Z; Peres, M A; Liu, P; Mejia, G C; Armfield, J M; Peres, K G

2017-12-01

The aim of this study was to investigate the association between early-life family income and dental pain experience from childhood to early adulthood. Data came from a 14-year prospective study (1991/1992-2005/2006) carried out in South Australia, which included children and adolescents aged 4-17 years (N = 9875) at baseline. The outcome was dental pain experience obtained at baseline, 14 years later in adulthood and at a middle point of time. The main explanatory variable was early-life family income collected at baseline. The prevalence of dental pain was 22.8% at baseline, 19.3% at 'middle time' and 39.3% at follow up. The proportion of people classified as 'poor' at baseline was 27.7%. Being poor early in life was significantly associated with dental pain at 14-year follow up (odds ratio = 1.45; 95% confidence interval = 1.27-1.66). Early-life relative poverty is associated with more frequent dental pain across the 14-year follow up and may be a key exposure variable for later dental conditions. © 2017 Australian Dental Association.

Interaction between genetic variants and exposure to Hurricane Katrina on post-traumatic stress and post-traumatic growth: a prospective analysis of low income adults.

PubMed

Dunn, Erin C; Solovieff, Nadia; Lowe, Sarah R; Gallagher, Patience J; Chaponis, Jonathan; Rosand, Jonathan; Koenen, Karestan C; Waters, Mary C; Rhodes, Jean E; Smoller, Jordan W

2014-01-01

There is considerable variation in psychological reactions to natural disasters, with responses ranging from relatively mild and transitory symptoms to severe and persistent posttraumatic stress (PTS). Some survivors also report post-traumatic growth (PTG), or positive psychological changes due to the experience and processing of the disaster and its aftermath. Gene-environment interaction (GxE) studies could offer new insight into the factors underlying variability in post-disaster psychological responses. However, few studies have explored GxE in a disaster context. We examined whether ten common variants in seven genes (BDNF, CACNA1C, CRHR1, FKBP5, OXTR, RGS2, SLC6A4) modified associations between Hurricane Katrina exposure and PTS and PTG. Data were from a prospective study of 205 low-income non-Hispanic Black parents residing in New Orleans prior to and following Hurricane Katrina. We found a significant association (after correction) between RGS2 (rs4606; p=0.0044) and PTG, which was mainly driven by a cross-over GxE (p=0.006), rather than a main genetic effect (p=0.071). The G (minor allele) was associated with lower PTG scores for low levels of Hurricane exposure and higher PTG scores for moderate and high levels of exposure. We also found a nominally significant association between variation in FKBP5 (rs1306780, p=0.0113) and PTG, though this result did not survive correction for multiple testing. Although the inclusion of low-income non-Hispanic Black parents allowed us to examine GxE among a highly vulnerable group, our findings may not generalize to other populations or groups experiencing other natural disasters. Moreover, not all participants invited to participate in the genetic study provided saliva. To our knowledge, this is the first study to identify GxE in the context of post-traumatic growth. Future studies are needed to clarify the role of GxE in PTS and PTG and post-disaster psychological responses, especially among vulnerable populations. Published by Elsevier B.V.

Interaction Between Genetic Variants and Exposure to Hurricane Katrina on Post-Traumatic Stress and Post-Traumatic Growth: A Prospective Analysis of Low Income Adults

PubMed Central

Dunn, Erin C.; Solovieff, Nadia; Lowe, Sarah R.; Gallagher, Patience J.; Chaponis, Jonathan; Rosand, Jonathan; Koenen, Karestan C.; Waters, Mary; Rhodes, Jean; Smoller, Jordan W.

2013-01-01

Background There is considerable variation in psychological reactions to natural disasters, with responses ranging from relatively mild and transitory symptoms to severe and persistent posttraumatic stress (PTS). Some survivors also report post-traumatic growth (PTG), or positive psychological changes due to the experience and processing of the disaster and its aftermath. Gene-environment interaction (GxE) studies could offer new insight into the factors underlying variability in post-disaster psychological responses. However, few studies have explored GxE in a disaster context. Methods We examined whether ten common variants in seven genes (BDNF, CACNA1C, CRHR1, FKBP5, OXTR, RGS2, SLC6A4) modified associations between Hurricane Katrina exposure and PTS and PTG. Data were from a prospective study of 205 low-income non-Hispanic Black parents residing in New Orleans prior to and following Hurricane Katrina. Results We found a significant association (after correction) between RGS2 (rs4606; p=0.0044) and PTG, which was mainly driven by a cross-over GxE (p=0.006), rather than a main genetic effect (p=0.071). The G (minor allele) was associated with lower PTG scores for low levels of Hurricane exposure and higher PTG scores for moderate and high levels of exposure. We also found a nominally significant association between variation in FKBP5 (rs1306780, p=0.0113) and PTG, though this result did not survive correction for multiple testing. Limitations Although the inclusion of low-income non-Hispanic Black parents allowed us to examine GxE among a highly vulnerable group, our findings may not generalize to other populations or groups experiencing other natural disasters. Moreover, not all participants invited to participate in the genetic study provided saliva. Conclusions To our knowledge, this is the first study to identify GxE in the context of post-traumatic growth. Future studies are needed to clarify the role of GxE in PTS and PTG and post-disaster psychological responses, especially among vulnerable populations. PMID:24161451

Quantification of allyl hexanoate in pineapple beverages and yogurts as a case study to characterise a source of uncertainty in dietary exposure assessment to flavouring substances.

PubMed

Raffo, A; D'Aloise, A; Magrì, A D; Leclercq, C

2012-01-01

One source of uncertainty in the estimation of dietary exposure to flavouring substances is the uncertainty in the occurrence and concentration levels of these substances naturally present or added to foodstuffs. The aim of this study was to assess the variability of concentration levels of allyl hexanoate, considered as a case study, in two main food categories to which it is often added: pineapple juice-based beverages and yogurts containing pineapple. Thirty-four beverages and 29 yogurts, with pineapple fruit or juice and added flavourings declared as ingredients on the package, were purchased from the local market (in Rome) and analysed. Analytical methods based on the stir bar sorptive extraction (SBSE) technique for the isolation of the target analyte, and on GC-MS analysis for final determination, were developed for the two food categories. In beverages, allyl hexanoate concentrations ranged from less than 0.01 to 16.71 mg l(-1), whereas in yogurts they ranged from 0.02 to 89.41 mg kg(-1). Average concentrations in beverages and yogurts with pineapple as the main fruit ingredient (1.91 mg l(-1) for beverages, 9.61 mg kg(-1) for yogurts) were in fair agreement with average use level data reported from industry surveys for the relevant food categories (4.5 and 6.0 mg kg(-1), respectively). Within the group of yogurts a single product was found to contain a level of allyl hexanoate more than 10-fold higher than the average reported use level. The screening techniques developed by the European Food Safety Authority (EFSA) using use level data provided by industry gave estimates of exposure that were of the same order of magnitude as the estimates obtained for regular consumers who would be loyal to the pineapple yogurt and beverage products containing the highest observed concentration of the substance of interest. In this specific case the uncertainty in the results obtained with the use of standard screening techniques for exposure assessment based on industry reported use levels is low.

Exposure to Terrorism and Violent Behavior among Adolescents in Israel

ERIC Educational Resources Information Center

Even-Chen, Merav Solomon; Itzhaky, Haya

2007-01-01

It is commonly assumed that exposure to terrorism may lead to violent behavior, but there is little empirical research on the relationship between these two variables. In the present paper, we examined the extent to which exposure to terrorism contributes to violent behavior among adolescents. In addition, we considered the role of environmental…

ANALYSIS OF COMPONENTS OF PARTICULATE MATTER (PM2.5) FOR AN EXPOSURE ASSESSMENT STUDY OF TWO SENSITIVE COHORTS IN ATLANTA, GA

EPA Science Inventory

Introduction
An exposure assessment study was conducted in Atlanta, GA during fall 1999 and spring 2000 to examine the short-term effects of exposure to particulate matter and gaseous air pollutants on heart rate variability (HRV). Characterization of particulate matter (PM...

Risk Factors in Early Child Development: Is Prenatal Cocaine/Polydrug Exposure a Key Variable?

ERIC Educational Resources Information Center

Phelps, Leadelle; Wallace, Nancy Virginia; Bontrager, Annie

1997-01-01

Assessed the effect of cocaine/polydrug in utero exposure on early childhood development while controlling for covariant factors. Analysis of two matched samples of preschoolers (20 with drug exposure and 20 without) revealed that both groups scored approximately one standard deviation below the expected mean in social skills, auditory…

Simultaneous exposure to concentrated ambient particles and acrolein causes cardiac effects mediated by parasympathetic modulation in mice

EPA Science Inventory

This study shows that exposure to CAPs and acrolein causes an increase in HRV that is mediated by the parasympathetic nervous system. Numerous studies show that short-term air pollution exposure modulates heart rate variability (HRV), which is an indicator of autonomic influence...

Evaluating MoE and its Uncertainty and Variability for Food Contaminants (EuroTox presentation)

EPA Science Inventory

Margin of Exposure (MoE), is a metric for quantifying the relationship between exposure and hazard. Ideally, it is the ratio of the dose associated with hazard and an estimate of exposure. For example, hazard may be characterized by a benchmark dose (BMD), and, for food contami...

A Comparison of Exposure Control Procedures in CATS Using the GPC Model

ERIC Educational Resources Information Center

Leroux, Audrey J.; Dodd, Barbara G.

2016-01-01

The current study compares the progressive-restricted standard error (PR-SE) exposure control method with the Sympson-Hetter, randomesque, and no exposure control (maximum information) procedures using the generalized partial credit model with fixed- and variable-length CATs and two item pools. The PR-SE method administered the entire item pool…

Development and Evaluation of a New Air Exchange Rate Algorithm for the Stochastic Human Exposure and Dose Simulation Model

EPA Science Inventory

between-home and between-city variability in residential pollutant infiltration. This is likely a result of differences in home ventilation, or air exchange rates (AER). The Stochastic Human Exposure and Dose Simulation (SHEDS) model is a population exposure model that uses a pro...

DYNAMIC CHANGES IN COLORED DISSOLVED ORGANIC MATTER AND TOTAL SUSPENDED MATTER CONTROL UV EXPOSURE OF CORAL REEFS IN THE FLORIDA KEYS

EPA Science Inventory

Variation in ultraviolet (UV) light exposure is one important environmental factor that influences the health of coral reefs. Here we present evidence that the reef tract in the Florida Keys experiences significantly higher variability in UV exposure than other surrounding coast...

The Variable Effects of Ozone and/or Diesel Particulate Inhalation Exposure on Allergic Airways Responses in Mice

EPA Science Inventory

Exposure to diesel exhaust particle matter (DEP) associated with the combustion of diesel fuel exacerbates asthma. Likewise, similar effects have been reported with exposure to the oxidizing air pollutant ozone (O₃). Since levels of both pollutants in ambient air are e...

Violence Exposure and Mental Health of College Students in the United States.

PubMed

Assari, Shervin; Moghani Lankarani, Maryam

2018-05-24

Background : Despite the well-established link between exposure to violence and mental health problems, less is known about this association among college students. The current study aimed to investigate the association between history of exposure to violence and mental health of American college students. Methods : Healthy Mind Study (HMS, 2016⁻2017) is a national online survey of 41,898 adult college students. The independent variable was lifetime history of exposure to violence (psychological, physical, and sexual). The dependent variables were anxiety, depression, and suicidality. Race, age, gender, sexual orientation, parental education, financial stress, transfer status, enrollment status, and graduate status were covariates. Linear and logistic regression models were used for data analysis. Results : History of exposure to violence was associated with all three aspects of poor mental health, namely general anxiety, depression, and suicidality. These associations were independent of covariates and type of abuse. Conclusions : There is a need to address various mental health needs of college students who have experienced various forms of violence. College students who screen positive for history of violence exposure should be evaluated for anxiety, depression, and suicidal behaviors.

Effects of acute exposure to WIFI signals (2.45GHz) on heart variability and blood pressure in Albinos rabbit.

PubMed

Saili, Linda; Hanini, Amel; Smirani, Chiraz; Azzouz, Ines; Azzouz, Amina; Sakly, Mohsen; Abdelmelek, Hafedh; Bouslama, Zihad

2015-09-01

Electrocardiogram and arterial pressure measurements were studied under acute exposures to WIFI (2.45GHz) during one hour in adult male rabbits. Antennas of WIFI were placed at 25cm at the right side near the heart. Acute exposure of rabbits to WIFI increased heart frequency (+22%) and arterial blood pressure (+14%). Moreover, analysis of ECG revealed that WIFI induced a combined increase of PR and QT intervals. By contrast, the same exposure failed to alter maximum amplitude and P waves. After intravenously injection of dopamine (0.50ml/kg) and epinephrine (0.50ml/kg) under acute exposure to RF we found that, WIFI alter catecholamines (dopamine, epinephrine) action on heart variability and blood pressure compared to control. These results suggest for the first time, as far as we know, that exposure to WIFI affect heart rhythm, blood pressure, and catecholamines efficacy on cardiovascular system; indicating that radiofrequency can act directly and/or indirectly on cardiovascular system. Copyright © 2015 Elsevier B.V. All rights reserved.

Operational and environmental determinants of in-vehicle CO and PM2.5 exposure.

PubMed

Alameddine, I; Abi Esber, L; Bou Zeid, E; Hatzopoulou, M; El-Fadel, M

2016-05-01

This study presents a modeling framework to quantify the complex roles that traffic, seasonality, vehicle characteristics, ventilation, meteorology, and ambient air quality play in dictating in-vehicle commuter exposure to CO and PM2.5. For this purpose, a comprehensive one-year monitoring program of 25 different variables was coupled with a multivariate regression analysis to develop models to predict in-vehicle CO and PM2.5 exposure using a database of 119 mobile tests and 120 fume leakage tests. The study aims to improve the understanding of in-cabin exposure, as well as interior-exterior pollutant exchange. Model results highlighted the strong correlation between out-vehicle and in-vehicle concentrations, with the effect of ventilation type only discerned for PM2.5 levels. Car type, road conditions, as well as meteorological conditions all played a significant role in modulating in-vehicle exposure. The CO and PM2.5 exposure models were able to explain 72 and 92% of the variability in measured concentrations, respectively. Both models exhibited robustness and no-evidence of over-fitting. Copyright © 2016 Elsevier B.V. All rights reserved.

Secondhand smoke exposure levels in outdoor hospitality venues: a qualitative and quantitative review of the research literature.

PubMed

Licht, Andrea S; Hyland, Andrew; Travers, Mark J; Chapman, Simon

2013-05-01

This paper considers the evidence on whether outdoor secondhand smoke (SHS) is present in hospitality venues at high levels enough to potentially pose health risks, particularly among employees. Searches in PubMed and Web of Science included combinations of environmental tobacco smoke, secondhand smoke, or passive smoke AND outdoor, yielding 217 and 5,199 results, respectively through June, 2012. Sixteen studies were selected that reported measuring any outdoor SHS exposures (particulate matter (PM) or other SHS indicators). The SHS measurement methods were assessed for inclusion of extraneous variables that may affect levels or the corroboration of measurements with known standards. The magnitude of SHS exposure (PM2.5) depends on the number of smokers present, measurement proximity, outdoor enclosures, and wind. Annual excess PM2.5 exposure of full-time waitstaff at outdoor smoking environments could average 4.0 to 12.2 μg/m3 under variable smoking conditions. Although highly transitory, outdoor SHS exposures could occasionally exceed annual ambient air quality exposure guidelines. Personal monitoring studies of waitstaff are warranted to corroborate these modeled estimates.

Long-term food-exposure of zebrafish to PCB mixtures mimicking some environmental situations induces ovary pathology and impairs reproduction ability.

PubMed

Daouk, Tarek; Larcher, Thibaut; Roupsard, François; Lyphout, Laura; Rigaud, Cyril; Ledevin, Mireille; Loizeau, Véronique; Cousin, Xavier

2011-10-01

Although the use of polychlorinated biphenyls (PCBs) has been banned for several decades, they are still present in the environment and are occasionally mechanically released from sediment or transferred through the trophic chain. Field analyses have established correlations between exposure to PCBs and alterations in fish physiology including reproductive function. Experimental exposures have been mainly performed using dioxin-like PCBs or other congeners at very high concentrations. However, these studies are often difficult to relate to real-life conditions. In the present study, we performed a life-cycle exposure using zebrafish model and mixtures representative of some environmental situations in terms of doses, composition and containing mainly non dioxin-like congeners. Exposure was performed through diet which is the main contamination route in the field. We demonstrated a bioaccumulation of PCBs in males and females as well as a maternal transfer to the eggs. Survival, growth and organ size were similar for all conditions. Several reproductive traits were altered after exposure to a PCB-contaminated diet, including a reduction in the number of fertilized eggs per spawn as well as an increase of the number of poorly fertilized spawns. This latter observation was found irrespective of the sex of contaminated fish. This is related to modifications of ovary histology revealing a decrease of maturing follicles and an increase of atretic follicles in the ovaries of females exposed to PCBs. These results indicate that exposure to PCBs mixtures mimicking some environmental situations, including mainly non dioxin-like congeners, can lead to a dramatic reduction in the number of offspring produced by a female over a lifetime. This is of great concern for wild species living under natural conditions. Copyright © 2011 Elsevier B.V. All rights reserved.

Effects of subchronic exposures to concentrated ambient particles (CAPs) in mice. III. Acute and chronic effects of CAPs on heart rate, heart-rate fluctuation, and body temperature.

PubMed

Hwang, Jing-Shiang; Nadziejko, Christine; Chen, Lung Chi

2005-04-01

Normal mice (C57) and mice prone to develop atherosclerosis (ApoE-/-) were implanted with electrocardiograph (EKG), core body temperature, and motion transmitters were exposed daily for 6 h to Tuxedo, NY, concentrated ambient particles (CAPs) for 5 day/wk during the spring and summer of 2003. The series of 5-min EKG monitoring and body-temperature measurements were obtained for each animal in the CAPs and filtered air sham exposure groups. Our hypothesis was that chronic exposure could cause cumulative health effects. We used our recently developed nonparametric method to estimate the daily time periods that mean heart rates (HR), body temperature, and physical activity differed significantly between the CAPs and sham exposed group. CAPs exposure most affected heart rate between 1:30 a.m. and 4:30 a.m. With the response variables being the average heart rate, body temperature, and physical activity, we adopted a two-stage modeling approach to obtain the estimates of chronic and acute effects on the changes of these three response variables. In the first stage, a time-varying model estimated daily crude effects. In the second stage, the true means of the estimated crude effects were modeled with a polynominal function of time for chronic effects, a linear term of daily CAPs exposure concentrations for acute effects, and a random component for unknown noise. A Bayesian framework combined these two stages. There were significant decreasing patterns of HR, body temperature, and physical activity for the ApoE-/- mice over the 5 mo of CAPs exposure, with smaller and nonsignificant changes for the C57 mice. The chronic effect changes of the three response variables for ApoE-/- mice were maximal in the last few weeks. There was also a significant relationship between CAPs exposure concentration and short-term changes of heart rate in ApoE-/- mice during exposure. Response variables were also defined for examining fluctuations of 5-min heart rates within long (i.e., 3-6 h) and short time periods (i.e., approximately 15 min). The results for the ApoE-/- mice showed that heart-rate fluctuation within the longer periods increased to 1.35-fold by the end of exposure experiment, while the heart-rate fluctuation within 15 min decreased to 0.7-fold.

Population variability in animal health: Influence on dose-exposure-response relationships: Part II: Modelling and simulation.

PubMed

Martinez, Marilyn N; Gehring, Ronette; Mochel, Jonathan P; Pade, Devendra; Pelligand, Ludovic

2018-05-28

During the 2017 Biennial meeting, the American Academy of Veterinary Pharmacology and Therapeutics hosted a 1-day session on the influence of population variability on dose-exposure-response relationships. In Part I, we highlighted some of the sources of population variability. Part II provides a summary of discussions on modelling and simulation tools that utilize existing pharmacokinetic data, can integrate drug physicochemical characteristics with species physiological characteristics and dosing information or that combine observed with predicted and in vitro information to explore and describe sources of variability that may influence the safe and effective use of veterinary pharmaceuticals. © 2018 John Wiley & Sons Ltd. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Towards the methodological optimization of the moss bag technique in terms of contaminants concentrations and replicability values

NASA Astrophysics Data System (ADS)

Ares, A.; Fernández, J. A.; Carballeira, A.; Aboal, J. R.

2014-09-01

The moss bag technique is a simple and economical environmental monitoring tool used to monitor air quality. However, routine use of the method is not possible because the protocols involved have not yet been standardized. Some of the most variable methodological aspects include (i) selection of moss species, (ii) ratio of moss weight to surface area of the bag, (iii) duration of exposure, and (iv) height of exposure. In the present study, the best option for each of these aspects was selected on the basis of the mean concentrations and data replicability of Cd, Cu, Hg, Pb and Zn measured during at least two exposure periods in environments affected by different degrees of contamination. The optimal choices for the studied aspects were the following: (i) Sphagnum denticulatum, (ii) 5.68 mg of moss tissue for each cm-2 of bag surface, (iii) 8 weeks of exposure, and (iv) 4 m height of exposure. Duration of exposure and height of exposure accounted for most of the variability in the data. The aim of this methodological study was to provide data to help establish a standardized protocol that will enable use of the moss bag technique by public authorities.

Colony Collapse Disorder: A Descriptive Study

PubMed Central

vanEngelsdorp, Dennis; Evans, Jay D.; Saegerman, Claude; Mullin, Chris; Haubruge, Eric; Nguyen, Bach Kim; Frazier, Maryann; Frazier, Jim; Cox-Foster, Diana; Chen, Yanping; Underwood, Robyn; Tarpy, David R.; Pettis, Jeffery S.

2009-01-01

Background Over the last two winters, there have been large-scale, unexplained losses of managed honey bee (Apis mellifera L.) colonies in the United States. In the absence of a known cause, this syndrome was named Colony Collapse Disorder (CCD) because the main trait was a rapid loss of adult worker bees. We initiated a descriptive epizootiological study in order to better characterize CCD and compare risk factor exposure between populations afflicted by and not afflicted by CCD. Methods and Principal Findings Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels), no single measure emerged as a most-likely cause of CCD. Bees in CCD colonies had higher pathogen loads and were co-infected with a greater number of pathogens than control populations, suggesting either an increased exposure to pathogens or a reduced resistance of bees toward pathogens. Levels of the synthetic acaricide coumaphos (used by beekeepers to control the parasitic mite Varroa destructor) were higher in control colonies than CCD-affected colonies. Conclusions/Significance This is the first comprehensive survey of CCD-affected bee populations that suggests CCD involves an interaction between pathogens and other stress factors. We present evidence that this condition is contagious or the result of exposure to a common risk factor. Potentially important areas for future hypothesis-driven research, including the possible legacy effect of mite parasitism and the role of honey bee resistance to pesticides, are highlighted. PMID:19649264

Colony collapse disorder: a descriptive study.

PubMed

Vanengelsdorp, Dennis; Evans, Jay D; Saegerman, Claude; Mullin, Chris; Haubruge, Eric; Nguyen, Bach Kim; Frazier, Maryann; Frazier, Jim; Cox-Foster, Diana; Chen, Yanping; Underwood, Robyn; Tarpy, David R; Pettis, Jeffery S

2009-08-03

Over the last two winters, there have been large-scale, unexplained losses of managed honey bee (Apis mellifera L.) colonies in the United States. In the absence of a known cause, this syndrome was named Colony Collapse Disorder (CCD) because the main trait was a rapid loss of adult worker bees. We initiated a descriptive epizootiological study in order to better characterize CCD and compare risk factor exposure between populations afflicted by and not afflicted by CCD. Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels), no single measure emerged as a most-likely cause of CCD. Bees in CCD colonies had higher pathogen loads and were co-infected with a greater number of pathogens than control populations, suggesting either an increased exposure to pathogens or a reduced resistance of bees toward pathogens. Levels of the synthetic acaricide coumaphos (used by beekeepers to control the parasitic mite Varroa destructor) were higher in control colonies than CCD-affected colonies. This is the first comprehensive survey of CCD-affected bee populations that suggests CCD involves an interaction between pathogens and other stress factors. We present evidence that this condition is contagious or the result of exposure to a common risk factor. Potentially important areas for future hypothesis-driven research, including the possible legacy effect of mite parasitism and the role of honey bee resistance to pesticides, are highlighted.

Radiation safety knowledge and practices among Irish orthopaedic trainees.

PubMed

Nugent, M; Carmody, O; Dudeney, S

2015-06-01

Fluoroscopy is frequently used in orthopaedic surgery, particularly in a trauma setting. Exposure of patients and staff to ionising radiation has been studied extensively; however, little work has been done to evaluate current knowledge and practices among orthopaedic trainees. This study aimed to investigate the knowledge and practices of Irish orthopaedic trainees regarding use of ionising radiation. A confidential internet-based survey on workplace radiation safety practices was distributed via email to 40 higher specialist trainees. Questions included related to radiation safety training and regular work practices. A total of 26 trainees completed the questionnaire (65% response rate). All reported regular exposure to ionising radiation. Compliance with body shields was high (25, 96%), however, other protective measures such as thyroid shields were less frequently employed. The 'as low as reasonably achievable principle' was practised regularly by 14 (54%). Radiation safety training was variable-while just over half (14) respondents felt adequately trained in radiation safety, 17 (65%) had attended a radiation protection course. Use of dosimeters was particularly poor, with only 4 (15%) using them regularly and most citing lack of availability as the main barrier. Although most Irish orthopaedic trainees have some knowledge regarding radiation safety, many do not regularly use all available measures to reduce exposure to ionising radiation. Barriers to use of protective mechanisms include lack of availability and perceived impracticality.

Reliability of concentrations of organophosphate pesticide metabolites in serial urine specimens from pregnancy in the Generation R study

PubMed Central

Spaan, Suzanne; Pronk, Anjoeka; Koch, Holger M.; Jusko, Todd A.; Jaddoe, Vincent W.V.; Shaw, Pamela A.; Tiemeier, Henning M.; Hofman, Albert; Pierik, Frank H.; Longnecker, Matthew P.

2014-01-01

The widespread use of organophosphate (OP) pesticides has resulted in ubiquitous exposure in humans, primarily through their diet. Exposure to OP pesticides may have adverse health effects, including neurobehavioral deficits in children. The optimal design of new studies requires data on the reliability of urinary measures of exposure. In the present study, urinary concentrations of six dialkyl phosphate (DAP) metabolites, the main urinary metabolites of OP pesticides, were determined in 120 pregnant women participating in the Generation R Study in Rotterdam. Intra-class correlation coefficients (ICCs) across serial urine specimens taken at <18, 18–25, and >25 weeks of pregnancy were determined to assess reliability. Geometric mean total DAP metabolite concentrations were 229 (GSD 2.2), 240 (GSD 2.1), and 224 (GSD 2.2) nmol/g creatinine across the three periods of gestation. Metabolite concentrations from the serial urine specimens in general correlated moderately. The ICCs for the six DAP metabolites ranged from 0.14 to 0.38 (0.30 for total DAPs), indicating weak to moderate reliability. Although the DAP metabolite levels observed in this study are slightly higher and slightly more correlated than in previous studies, the low to moderate reliability indicates a high degree of within-person variability, which presents challenges for designing well-powered epidemiologic studies. PMID:25515376

Toxicity of aged gasoline exhaust particles to normal and diseased airway epithelia

NASA Astrophysics Data System (ADS)

Künzi, Lisa; Krapf, Manuel; Daher, Nancy; Dommen, Josef; Jeannet, Natalie; Schneider, Sarah; Platt, Stephen; Slowik, Jay G.; Baumlin, Nathalie; Salathe, Matthias; Prévôt, André S. H.; Kalberer, Markus; Strähl, Christof; Dümbgen, Lutz; Sioutas, Constantinos; Baltensperger, Urs; Geiser, Marianne

2015-06-01

Particulate matter (PM) pollution is a leading cause of premature death, particularly in those with pre-existing lung disease. A causative link between particle properties and adverse health effects remains unestablished mainly due to complex and variable physico-chemical PM parameters. Controlled laboratory experiments are required. Generating atmospherically realistic aerosols and performing cell-exposure studies at relevant particle-doses are challenging. Here we examine gasoline-exhaust particle toxicity from a Euro-5 passenger car in a uniquely realistic exposure scenario, combining a smog chamber simulating atmospheric ageing, an aerosol enrichment system varying particle number concentration independent of particle chemistry, and an aerosol deposition chamber physiologically delivering particles on air-liquid interface (ALI) cultures reproducing normal and susceptible health status. Gasoline-exhaust is an important PM source with largely unknown health effects. We investigated acute responses of fully-differentiated normal, distressed (antibiotics-treated) normal, and cystic fibrosis human bronchial epithelia (HBE), and a proliferating, single-cell type bronchial epithelial cell-line (BEAS-2B). We show that a single, short-term exposure to realistic doses of atmospherically-aged gasoline-exhaust particles impairs epithelial key-defence mechanisms, rendering it more vulnerable to subsequent hazards. We establish dose-response curves at realistic particle-concentration levels. Significant differences between cell models suggest the use of fully-differentiated HBE is most appropriate in future toxicity studies.

Risk assessment of dietary exposure to phytosterol oxidation products from baked food in China.

PubMed

Hu, Yinzhou; Wang, Mengmeng; Huang, Weisu; Yang, Guoliang; Lou, Tiantian; Lai, Shiyun; Lu, Baiyi; Zheng, Lufei

2018-02-01

Phytosterols are nutritional phytochemicals that may undergo oxidation and be transformed into phytosterol oxidation products (POPs), thus inducing pathological and toxic effects. This work investigated four main phytosterols and 28 POPs in 104 kinds of commercial baked food by using GC-MS. The dietary exposure and hazard index values (HI) associated with POPs from baked food consumption in China were estimated by using Monte Carlo simulation. Concentrations of the total phytosterols were between 3.39 and 209.80 μg/g. The total concentrations of POPs, including 5α,6α/5β,6β-epoxysterols, 7-ketosterol, 7α/7β-hydroxysterols, 6-hydroxysterols, and triols, ranged from 0.37 to 27.81 μg/g. The median dietary exposure of POP contents in baked food for four age groups in China were 10.91 (children), 6.20 (adolescents), 3.63 (adults), and 3.40 (seniors) mg/(kg×day). Risk assessment of median HI with respect to POPs indicated no risk (HI <1) for people in adolescents, adults, and seniors in the country area of China, while a risk (1 < HI < 10) would refer to the baked food consumption of people in urban area and children in country area of China. Sensitivity and uncertainty analysis showed that the most significant variables for each age group in China were POP concentration, body weight, and ingestion rate.

Toxicity of aged gasoline exhaust particles to normal and diseased airway epithelia

PubMed Central

Künzi, Lisa; Krapf, Manuel; Daher, Nancy; Dommen, Josef; Jeannet, Natalie; Schneider, Sarah; Platt, Stephen; Slowik, Jay G.; Baumlin, Nathalie; Salathe, Matthias; Prévôt, André S. H.; Kalberer, Markus; Strähl, Christof; Dümbgen, Lutz; Sioutas, Constantinos; Baltensperger, Urs; Geiser, Marianne

2015-01-01

Particulate matter (PM) pollution is a leading cause of premature death, particularly in those with pre-existing lung disease. A causative link between particle properties and adverse health effects remains unestablished mainly due to complex and variable physico-chemical PM parameters. Controlled laboratory experiments are required. Generating atmospherically realistic aerosols and performing cell-exposure studies at relevant particle-doses are challenging. Here we examine gasoline-exhaust particle toxicity from a Euro-5 passenger car in a uniquely realistic exposure scenario, combining a smog chamber simulating atmospheric ageing, an aerosol enrichment system varying particle number concentration independent of particle chemistry, and an aerosol deposition chamber physiologically delivering particles on air-liquid interface (ALI) cultures reproducing normal and susceptible health status. Gasoline-exhaust is an important PM source with largely unknown health effects. We investigated acute responses of fully-differentiated normal, distressed (antibiotics-treated) normal, and cystic fibrosis human bronchial epithelia (HBE), and a proliferating, single-cell type bronchial epithelial cell-line (BEAS-2B). We show that a single, short-term exposure to realistic doses of atmospherically-aged gasoline-exhaust particles impairs epithelial key-defence mechanisms, rendering it more vulnerable to subsequent hazards. We establish dose-response curves at realistic particle-concentration levels. Significant differences between cell models suggest the use of fully-differentiated HBE is most appropriate in future toxicity studies. PMID:26119831

Germination of Medicago sativa is inhibited by soluble compounds in cement dust.

PubMed

Lafragüeta, Cristina; García-Criado, Balbino; Arranz, Angel; Vázquez-de-Aldana, Beatriz R

2014-01-01

Deposition of cement dust on soils and plant surfaces is known to affect plant growth and the species composition of plant communities, but little is known about its effects (and those of its pH and constituents) on germination. Therefore, the aim of this study was to assess the toxicity of an aqueous cement extract, constituents of the extract and pH on the germination of seeds of a selected species, Medicago sativa. First, the effects of the extract were tested in assays with concentrations and exposure durations ranging from 0 to 1.0 g/mL and 4 to 96 h, respectively. At 0.8 g/mL, the extract strongly inhibited germination; a 4-h exposure reduced the germination rate, from 77 ± 1.8 to 50 ± 2.6% (mean ± SE), while 8-h exposure completely inhibited it. Further, treatment at this concentration killed the non-germinating seeds, thus the inhibition was due to toxic effects. Neither the pH of the extract nor the concentration of its main soluble elements separately (K, Ca, S, Na, or Cr) caused the toxicity since germination rates were not significantly reduced when these variables were tested individually. However, a mixture of the elements in solution reduced germination rates, suggesting that they have adverse synergistic effects.

Toxicity of aged gasoline exhaust particles to normal and diseased airway epithelia.

PubMed

Künzi, Lisa; Krapf, Manuel; Daher, Nancy; Dommen, Josef; Jeannet, Natalie; Schneider, Sarah; Platt, Stephen; Slowik, Jay G; Baumlin, Nathalie; Salathe, Matthias; Prévôt, André S H; Kalberer, Markus; Strähl, Christof; Dümbgen, Lutz; Sioutas, Constantinos; Baltensperger, Urs; Geiser, Marianne

2015-06-29

Particulate matter (PM) pollution is a leading cause of premature death, particularly in those with pre-existing lung disease. A causative link between particle properties and adverse health effects remains unestablished mainly due to complex and variable physico-chemical PM parameters. Controlled laboratory experiments are required. Generating atmospherically realistic aerosols and performing cell-exposure studies at relevant particle-doses are challenging. Here we examine gasoline-exhaust particle toxicity from a Euro-5 passenger car in a uniquely realistic exposure scenario, combining a smog chamber simulating atmospheric ageing, an aerosol enrichment system varying particle number concentration independent of particle chemistry, and an aerosol deposition chamber physiologically delivering particles on air-liquid interface (ALI) cultures reproducing normal and susceptible health status. Gasoline-exhaust is an important PM source with largely unknown health effects. We investigated acute responses of fully-differentiated normal, distressed (antibiotics-treated) normal, and cystic fibrosis human bronchial epithelia (HBE), and a proliferating, single-cell type bronchial epithelial cell-line (BEAS-2B). We show that a single, short-term exposure to realistic doses of atmospherically-aged gasoline-exhaust particles impairs epithelial key-defence mechanisms, rendering it more vulnerable to subsequent hazards. We establish dose-response curves at realistic particle-concentration levels. Significant differences between cell models suggest the use of fully-differentiated HBE is most appropriate in future toxicity studies.

Associations of Baroreflex Sensitivity, Heart Rate Variability, and Initial Orthostatic Hypotension with Prenatal and Recent Postnatal Methylmercury Exposure in the Seychelles Child Development Study at Age 19 Years

PubMed Central

Périard, Daniel; Beqiraj, Bujar; Hayoz, Daniel; Viswanathan, Bharathi; Evans, Katie; Thurston, Sally W.; Davidson, Philip W.; Myers, Gary J.; Bovet, Pascal

2015-01-01

Background: A few studies have suggested an association between prenatal exposure to methylmercury and decreased heart rate variability (HRV) related to autonomic heart function, but no study has examined this association using baroreflex sensitivity (BRS). In this study we assessed the distribution of BRS and immediate orthostatic hypotension (IOH) in young Seychellois adults and their associations with exposure to prenatal and recent postnatal methylmercury. Methods: Subjects in theSeychelles Child Development Study (SCDS) main cohort were evaluated at age 19 years. Non-invasive beat-to-beat blood pressure (BP) monitoring (Finapres, Ohmeda) was performed at rest and during active standing in 95 consecutive subjects. Recent postnatal mercury exposure was measured in subjects’ hair at the age of 19 years and prenatal exposure in maternal hair grown during pregnancy. BRS was estimated by sequence analysis to identify spontaneous ascending and descending BP ramps. HRV was estimated by the following markers: PNN50 (relative numbers of normal-to-normal intervals which are shorter by more than 50 ms than the immediately following normal-to-normal intervals); rMSSD (root mean of the squared sum of successive interval differences); LF/HF (low frequency/high frequency component ratio); ratio of the mean expiratory/inspiratory RR intervals (EI ratio); and the ratio between the longest RR interval 30 s after active standing and the shortest RR interval at 15 s (Max30/Min15). IOH was estimated by the deepest BP fall within the first 15 s after active standing up. Results: Prenatal MeHg exposures were similar in boys and girls (6.7 ± 4.3, 6.7 ± 3.8 ng/g) but recent postnatal mercury levels were higher in males than females (11.2 ± 5.8 vs 7.9 ± 4.3 ng/g, p = 0.003). Markers of autonomic heart rate control were within the normal range (BRS: 24.8 ± 7 ms/mm Hg, PNN50: 24.9 ± 6.8%, rMSSD: 68 ± 22, LF/HF: 0.61 ± 0.28) in both sexes. After standing, 51.4% of subjects had a transient systolic BP drop >40 mm Hg, but only 5.3% reported dizziness or had syncope. Prenatal and recent postnatal MeHg levels, overall, were not associated with BRS, E/I ratio, PNN50, rMSSD, LF/HF ratio, Max30/Min15 ratio, and IOH. Conclusions: This study provides no support for the hypothesis that prenatal or recent postnatal MeHg exposure from fish consumption is associated with impaired autonomic heart rate control. PMID:25807149

Associations of baroreflex sensitivity, heart rate variability, and initial orthostatic hypotension with prenatal and recent postnatal methylmercury exposure in the Seychelles Child Development Study at age 19 years.

PubMed

Périard, Daniel; Beqiraj, Bujar; Hayoz, Daniel; Viswanathan, Bharathi; Evans, Katie; Thurston, Sally W; Davidson, Philip W; Myers, Gary J; Bovet, Pascal

2015-03-23

A few studies have suggested an association between prenatal exposure to methylmercury and decreased heart rate variability (HRV) related to autonomic heart function, but no study has examined this association using baroreflex sensitivity (BRS). In this study we assessed the distribution of BRS and immediate orthostatic hypotension (IOH) in young Seychellois adults and their associations with exposure to prenatal and recent postnatal methylmercury. Subjects in the Seychelles Child Development Study (SCDS) main cohort were evaluated at age 19 years. Non-invasive beat-to-beat blood pressure (BP) monitoring (Finapres, Ohmeda) was performed at rest and during active standing in 95 consecutive subjects. Recent postnatal mercury exposure was measured in subjects' hair at the age of 19 years and prenatal exposure in maternal hair grown during pregnancy. BRS was estimated by sequence analysis to identify spontaneous ascending and descending BP ramps. HRV was estimated by the following markers: PNN50 (relative numbers of normal-to-normal intervals which are shorter by more than 50 ms than the immediately following normal-to-normal intervals); rMSSD (root mean of the squared sum of successive interval differences); LF/HF (low frequency/high frequency component ratio); ratio of the mean expiratory/inspiratory RR intervals (EI ratio); and the ratio between the longest RR interval 30 s after active standing and the shortest RR interval at 15 s (Max30/Min15). IOH was estimated by the deepest BP fall within the first 15 s after active standing up. Prenatal MeHg exposures were similar in boys and girls (6.7±4.3, 6.7±3.8 ng/g) but recent postnatal mercury levels were higher in males than females (11.2±5.8 vs 7.9±4.3 ng/g, p=0.003). Markers of autonomic heart rate control were within the normal range (BRS: 24.8±7 ms/mm Hg, PNN50: 24.9±6.8%, rMSSD: 68±22, LF/HF: 0.61±0.28) in both sexes. After standing, 51.4% of subjects had a transient systolic BP drop>40 mm Hg, but only 5.3% reported dizziness or had syncope. Prenatal and recent postnatal MeHg levels, overall, were not associated with BRS, E/I ratio, PNN50, rMSSD, LF/HF ratio, Max30/Min15 ratio, and IOH. This study provides no support for the hypothesis that prenatal or recent postnatal MeHg exposure from fish consumption is associated with impaired autonomic heart rate control.

Macroalgal communities on multi-stressed coral reefs in the Caribbean: Long-term changes, spatial variations, and relationships with environmental variables

NASA Astrophysics Data System (ADS)

Sangil, Carlos; Guzman, Hector M.

2016-11-01

Long-term changes in macroalgal cover, spatial variation between macroalgal communities, and relationships with environmental variables and benthic groups were assessed in coral reefs along the Caribbean coast of Panama. Sampling was conducted in two regions: Western and Central. Data collected between 2000 and 2012 showed a continuous increase in macroalgal abundance, although patterns differed according to region and site. There were differences in macroalgal communities between regions, as well as within regions between different wave-exposure levels. There were also differences between sites within regions exposed to the same level of wave action. Multivariate analysis found that wave exposure along with herbivore density (Echinometra viridis) and sedimentation were the variables that explained most of the variability between communities. Other variables such as Echinometra lucunter and Diadema antillarum densities, fish density, productivity, and live coral cover had significant relationships with community structure, but explained less of the variability.

Determinants of alcohol use, risky sexual behavior and sexual health problems among men in low income communities of Mumbai, India.

PubMed

Singh, S K; Schensul, Jean J; Gupta, Kamla; Maharana, Barsharani; Kremelberg, David; Berg, Marlene

2010-08-01

This paper summarizes the main results of the survey component of a mixed methods study of alcohol and sexual risk in a general population of young men 18-29 residing in low income communities in the Greater Mumbai area. The survey included demographic variables, and scales and indices measuring work related stress, social influence, exposure to alcohol in childhood, and currently, hyper masculinity, exposure to media and pornography, risk related leisure time activities and alcohol and alcohol/sex expectancies. Measures of alcohol use included frequency/amount/contextual use of six different types of alcohol, a general estimate of frequency and amount (AUDIT), and an estimate of total ml. alcohol consumed in the past 30 days, based on estimates of alcohol content in all types of alcohol consumed, by unit of consumption (glass, peg, bottle) etc. Sexual outcome measures included types and number of partners ever and in past year with and without alcohol, and a critical event with most recent partner (with or without alcohol) and culturally specific indicators of sexual health related to sexual risk taking. A cluster sampling protocol and the use of a screener produced a sample of 1239 men, 1071 thirty day drinkers and 161 nondrinkers. Logistic regression analysis (binary and multinomial) showed relationships between predictor variables and alcohol consumption and alcohol and sexual risk indicators as well as two of the sexual health indicators associated with extramarital sex. Risk behaviors are associated with higher levels of alcohol consumption in this low risk general population of married and unmarried men. Implications for intervention include: (a) reducing or eliminating home drinking, to reduce early childhood exposure; (b) including alcohol in sexual risk and HIV prevention programs; (c) improving couples (married or unmarried) communication to reduce men's search for sexual alternatives, and (d) treating garmi as an indicator of sexual risk taking rather than STIs.

Determinants of Alcohol Use, Risky Sexual Behavior and Sexual Health Problems Among Men in Low Income Communities of Mumbai, India

PubMed Central

Schensul, Jean J.; Gupta, Kamla; Maharana, Barsharani; Kremelberg, David; Berg, Marlene

2015-01-01

This paper summarizes the main results of the survey component of a mixed methods study of alcohol and sexual risk in a general population of young men 18–29 residing in low income communities in the Greater Mumbai area. The survey included demographic variables, and scales and indices measuring work related stress, social influence, exposure to alcohol in childhood, and currently, hyper masculinity, exposure to media and pornography, risk related leisure time activities and alcohol and alcohol/sex expectancies. Measures of alcohol use included frequency/amount/contextual use of six different types of alcohol, a general estimate of frequency and amount (AUDIT), and an estimate of total ml. alcohol consumed in the past 30 days, based on estimates of alcohol content in all types of alcohol consumed, by unit of consumption (glass, peg, bottle) etc. Sexual outcome measures included types and number of partners ever and in past year with and without alcohol, and a critical event with most recent partner (with or without alcohol) and culturally specific indicators of sexual health related to sexual risk taking. A cluster sampling protocol and the use of a screener produced a sample of 1239 men, 1071 thirty day drinkers and 161 nondrinkers. Logistic regression analysis (binary and multinomial) showed relationships between predictor variables and alcohol consumption and alcohol and sexual risk indicators as well as two of the sexual health indicators associated with extramarital sex. Risk behaviors are associated with higher levels of alcohol consumption in this low risk general population of married and unmarried men. Implications for intervention include: (a) reducing or eliminating home drinking, to reduce early childhood exposure; (b) including alcohol in sexual risk and HIV prevention programs; (c) improving couples (married or unmarried) communication to reduce men’s search for sexual alternatives, and (d) treating garmi as an indicator of sexual risk taking rather than STIs. PMID:20567895

Variables that influence BRAF mutation probability: A next-generation sequencing, non-interventional investigation of BRAFV600 mutation status in melanoma.

PubMed

Gaiser, Maria Rita; Skorokhod, Alexander; Gransheier, Diana; Weide, Benjamin; Koch, Winfried; Schif, Birgit; Enk, Alexander; Garbe, Claus; Bauer, Jürgen

2017-01-01

The incidence of melanoma, particularly in older patients, has steadily increased over the past few decades. Activating mutations of BRAF, the majority occurring in BRAFV600, are frequently detected in melanoma; however, the prognostic significance remains unclear. This study aimed to define the probability and distribution of BRAFV600 mutations, and the clinico-pathological factors that may affect BRAF mutation status, in patients with advanced melanoma using next-generation sequencing. This was a non-interventional, retrospective study of BRAF mutation testing at two German centers, in Heidelberg and Tübingen. Archival tumor samples from patients with histologically confirmed melanoma (stage IIIB, IIIC, IV) were analyzed using PCR amplification and deep sequencing. Clinical, histological, and mutation data were collected. The statistical influence of patient- and tumor-related characteristics on BRAFV600 mutation status was assessed using multiple logistic regression (MLR) and a prediction profiler. BRAFV600 mutation status was assessed in 453 samples. Mutations were detected in 57.6% of patients (n = 261), with 48.1% (n = 102) at the Heidelberg site and 66.0% (n = 159) at the Tübingen site. The decreasing influence of increasing age on mutation probability was quantified. A main effects MLR model identified age (p = 0.0001), center (p = 0.0004), and melanoma subtype (p = 0.014) as significantly influencing BRAFV600 mutation probability; ultraviolet (UV) exposure showed a statistical trend (p = 0.1419). An interaction model of age versus other variables showed that center (p<0.0001) and melanoma subtype (p = 0.0038) significantly influenced BRAF mutation probability; age had a statistically significant effect only as part of an interaction with both UV exposure (p = 0.0110) and melanoma subtype (p = 0.0134). This exploratory study highlights that testing center, melanoma subtype, and age in combination with UV exposure and melanoma subtype significantly influence BRAFV600 mutation probability in patients with melanoma. Further validation of this model, in terms of reproducibility and broader relevance, is required.

Differential expression profiling of the hepatic proteome in a rat model of dioxin resistance: correlation with genomic and transcriptomic analyses.

PubMed

Pastorelli, Roberta; Carpi, Donatella; Campagna, Roberta; Airoldi, Luisa; Pohjanvirta, Raimo; Viluksela, Matti; Hakansson, Helen; Boutros, Paul C; Moffat, Ivy D; Okey, Allan B; Fanelli, Roberto

2006-05-01

One characteristic feature of acute 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity is dramatic interspecies and interstrain variability in sensitivity. This complicates dioxin risk assessment for humans. However, this variability also provides a means of characterizing mechanisms of dioxin toxicity. Long-Evans (Turku/AB) rats are orders of magnitude more susceptible to TCDD lethality than Han/Wistar (Kuopio) rats, and this difference constitutes a very useful model for identifying mechanisms of dioxin toxicity. We adopted a proteomic approach to identify the differential effects of TCDD exposure on liver protein expression in Han/Wistar rats as compared with Long-Evans rats. This allows determination of which, if any, protein markers are indicative of differences in dioxin susceptibility and/or responsible for conferring resistance. Differential protein expression in total liver protein was assessed using two-dimensional gel electrophoresis, computerized gel image analysis, in-gel digestion, and mass spectrometry. We observed significant changes in the abundance of several proteins, which fall into three general classes: (i) TCDD-independent and exclusively strain-specific (e.g. isoforms of the protein-disulfide isomerase A3, regucalcin, and agmatine ureohydrolase); (ii) strain-independent and only dependent on TCDD exposure (e.g. aldehyde dehydrogenase 3A1 and rat selenium-binding protein 2); (iii) dependent on both TCDD exposure and strain (e.g. oxidative stress-related proteins, apoptosis-inducing factor, and MAWD-binding protein). By integrating transcriptomic (microarray) data and genomic data (computational search of regulatory elements), we found that protein expression levels were mainly controlled at the level of transcription. These results reveal, for the first time, a subset of hepatic proteins that are differentially regulated in response to TCDD in a strain-specific manner. Some of these differential responses may play a role in establishing the major differences in TCDD response between these two strains of rats. As such, our work is expected to lead to new insights into the mechanism of TCDD toxicity and resistance.

A simulation study to quantify the impacts of exposure measurement error on air pollution health risk estimates in copollutant time-series models.

PubMed

Dionisio, Kathie L; Chang, Howard H; Baxter, Lisa K

2016-11-25

Exposure measurement error in copollutant epidemiologic models has the potential to introduce bias in relative risk (RR) estimates. A simulation study was conducted using empirical data to quantify the impact of correlated measurement errors in time-series analyses of air pollution and health. ZIP-code level estimates of exposure for six pollutants (CO, NO x , EC, PM 2.5 , SO 4 , O 3 ) from 1999 to 2002 in the Atlanta metropolitan area were used to calculate spatial, population (i.e. ambient versus personal), and total exposure measurement error. Empirically determined covariance of pollutant concentration pairs and the associated measurement errors were used to simulate true exposure (exposure without error) from observed exposure. Daily emergency department visits for respiratory diseases were simulated using a Poisson time-series model with a main pollutant RR = 1.05 per interquartile range, and a null association for the copollutant (RR = 1). Monte Carlo experiments were used to evaluate the impacts of correlated exposure errors of different copollutant pairs. Substantial attenuation of RRs due to exposure error was evident in nearly all copollutant pairs studied, ranging from 10 to 40% attenuation for spatial error, 3-85% for population error, and 31-85% for total error. When CO, NO x or EC is the main pollutant, we demonstrated the possibility of false positives, specifically identifying significant, positive associations for copollutants based on the estimated type I error rate. The impact of exposure error must be considered when interpreting results of copollutant epidemiologic models, due to the possibility of attenuation of main pollutant RRs and the increased probability of false positives when measurement error is present.

Health and Household Air Pollution from Solid Fuel Use: The Need for Improved Exposure Assessment

PubMed Central

Peel, Jennifer L.; Balakrishnan, Kalpana; Breysse, Patrick N.; Chillrud, Steven N.; Naeher, Luke P.; Rodes, Charles E.; Vette, Alan F.; Balbus, John M.

2013-01-01

Background: Nearly 3 billion people worldwide rely on solid fuel combustion to meet basic household energy needs. The resulting exposure to air pollution causes an estimated 4.5% of the global burden of disease. Large variability and a lack of resources for research and development have resulted in highly uncertain exposure estimates. Objective: We sought to identify research priorities for exposure assessment that will more accurately and precisely define exposure–response relationships of household air pollution necessary to inform future cleaner-burning cookstove dissemination programs. Data Sources: As part of an international workshop in May 2011, an expert group characterized the state of the science and developed recommendations for exposure assessment of household air pollution. Synthesis: The following priority research areas were identified to explain variability and reduce uncertainty of household air pollution exposure measurements: improved characterization of spatial and temporal variability for studies examining both short- and long-term health effects; development and validation of measurement technology and approaches to conduct complex exposure assessments in resource-limited settings with a large range of pollutant concentrations; and development and validation of biomarkers for estimating dose. Addressing these priority research areas, which will inherently require an increased allocation of resources for cookstove research, will lead to better characterization of exposure–response relationships. Conclusions: Although the type and extent of exposure assessment will necessarily depend on the goal and design of the cookstove study, without improved understanding of exposure–response relationships, the level of air pollution reduction necessary to meet the health targets of cookstove interventions will remain uncertain. Citation: Clark ML, Peel JL, Balakrishnan K, Breysse PN, Chillrud SN, Naeher LP, Rodes CE, Vette AF, Balbus JM. 2013. Health and household air pollution from solid fuel use: the need for improved exposure assessment. Environ Health Perspect 121:1120–1128; http://dx.doi.org/10.1289/ehp.1206429 PMID:23872398

Simulation of population-based commuter exposure to NO₂ using different air pollution models.

PubMed

Ragettli, Martina S; Tsai, Ming-Yi; Braun-Fahrländer, Charlotte; de Nazelle, Audrey; Schindler, Christian; Ineichen, Alex; Ducret-Stich, Regina E; Perez, Laura; Probst-Hensch, Nicole; Künzli, Nino; Phuleria, Harish C

2014-05-12

We simulated commuter routes and long-term exposure to traffic-related air pollution during commute in a representative population sample in Basel (Switzerland), and evaluated three air pollution models with different spatial resolution for estimating commute exposures to nitrogen dioxide (NO2) as a marker of long-term exposure to traffic-related air pollution. Our approach includes spatially and temporally resolved data on actual commuter routes, travel modes and three air pollution models. Annual mean NO2 commuter exposures were similar between models. However, we found more within-city and within-subject variability in annual mean (±SD) NO2 commuter exposure with a high resolution dispersion model (40 ± 7 µg m(-3), range: 21-61) than with a dispersion model with a lower resolution (39 ± 5 µg m(-3); range: 24-51), and a land use regression model (41 ± 5 µg m(-3); range: 24-54). Highest median cumulative exposures were calculated along motorized transport and bicycle routes, and the lowest for walking. For estimating commuter exposure within a city and being interested also in small-scale variability between roads, a model with a high resolution is recommended. For larger scale epidemiological health assessment studies, models with a coarser spatial resolution are likely sufficient, especially when study areas include suburban and rural areas.

Comparison of average global exposure of population induced by a macro 3G network in different geographical areas in France and Serbia.

PubMed

Huang, Yuanyuan; Varsier, Nadège; Niksic, Stevan; Kocan, Enis; Pejanovic-Djurisic, Milica; Popovic, Milica; Koprivica, Mladen; Neskovic, Aleksandar; Milinkovic, Jelena; Gati, Azeddine; Person, Christian; Wiart, Joe

2016-09-01

This article is the first thorough study of average population exposure to third generation network (3G)-induced electromagnetic fields (EMFs), from both uplink and downlink radio emissions in different countries, geographical areas, and for different wireless device usages. Indeed, previous publications in the framework of exposure to EMFs generally focused on individual exposure coming from either personal devices or base stations. Results, derived from device usage statistics collected in France and Serbia, show a strong heterogeneity of exposure, both in time, that is, the traffic distribution over 24 h was found highly variable, and space, that is, the exposure to 3G networks in France was found to be roughly two times higher than in Serbia. Such heterogeneity is further explained based on real data and network architecture. Among those results, authors show that, contrary to popular belief, exposure to 3G EMFs is dominated by uplink radio emissions, resulting from voice and data traffic, and average population EMF exposure differs from one geographical area to another, as well as from one country to another, due to the different cellular network architectures and variability of mobile usage. Bioelectromagnetics. 37:382-390, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Modelling survival: exposure pattern, species sensitivity and uncertainty

PubMed Central

Ashauer, Roman; Albert, Carlo; Augustine, Starrlight; Cedergreen, Nina; Charles, Sandrine; Ducrot, Virginie; Focks, Andreas; Gabsi, Faten; Gergs, André; Goussen, Benoit; Jager, Tjalling; Kramer, Nynke I.; Nyman, Anna-Maija; Poulsen, Veronique; Reichenberger, Stefan; Schäfer, Ralf B.; Van den Brink, Paul J.; Veltman, Karin; Vogel, Sören; Zimmer, Elke I.; Preuss, Thomas G.

2016-01-01

The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test the ability of GUTS to predict survival of aquatic organisms across different pesticide exposure patterns, time scales and species. Firstly, using synthetic data, we identified experimental data requirements which allow for the estimation of all parameters of the GUTS proper model. Secondly, we assessed how well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates to build species sensitivity distributions for different exposure patterns. We find that GUTS adequately predicts survival across exposure patterns that vary over time. When toxicity is assessed for time-variable concentrations species may differ in their responses depending on the exposure profile. This can result in different species sensitivity rankings and safe levels. The interplay of exposure pattern and species sensitivity deserves systematic investigation in order to better understand how organisms respond to stress, including humans. PMID:27381500

Increasing the understanding of chemical concepts: The effectiveness of multiple exposures

NASA Astrophysics Data System (ADS)

Bius, Janet H.

Chemistry is difficult because it has multilevels of knowledge with each level presenting challenges in vocabulary, abstract thinking, and symbolic language. Students have to be able to transfer between levels to understand the concepts and the theoretical models of chemistry. The cognitive theories of constructivism and cognitive-load theory are used to explain the difficulties novice learners have with the subject of chemistry and methods to increase success for students. The relationship between external representations, misconceptions and topics on the success of students are addressed. If students do not know the formalisms associated with chemical diagrams and graphs, the representations will decrease student success. Misconceptions can be formed when new information is interpreted based on pre-existing knowledge that is faulty. Topics with large amount of interacting elements that must be processed simultaneously are considered difficult to understand. New variables were created to measure the number of times a student is exposed to a chemical concept. Each variable was coded according to topic and learning environment, which are the lecture and laboratory components of the course, homework assignments and textbook examples. The exposure variables are used to measure the success rate of students on similar exam questions. Question difficulty scales were adapted for this project from those found in the chemical education literature. The exposure variables were tested on each level of the difficulty scales to determine their effect at decreasing the cognitive demand of these questions. The subjects of this study were freshmen science majors at a large Midwest university. The effects of the difficulty scales and exposure variables were measured for those students whose exam scores were in the upper one-fourth percentile, for students whose test scores were in the middle one-half percentile, and the lower one-fourth percentile are those students that scored the lowest on the exam. The most difficult for all three percentiles were the topics of acid/base equilibria and aqueous equilibria. The exposure variables of recall and algorithmic homework increased student success for all percentiles. Students perform better on exam questions when they understand the terminology and symbolic representations of a topic.

Effects of anti-obesity messages on women's body image and eating behaviour.

PubMed

Shentow-Bewsh, Rachel; Keating, Leah; Mills, Jennifer S

2016-01-01

It has been suggested that obesity stigmatization contributes to negative mental health outcomes, particularly among overweight individuals. This study examined the effects of exposure to media-portrayed anti-obesity messages on women's state self-esteem, body esteem, and food intake. It was hypothesized that exposure to anti-obesity messages would result in decreased state self-esteem and body esteem and in increased food intake, and that these effects would be more pronounced in individuals with either higher BMI or stronger perceived pressure to be thin. Participants were randomly assigned to one of three experimental conditions in which they either: read a fictitious media article containing either anti-obesity messages or non-obesity-related health messages, or completed a neutral control task (word search). State self-esteem and body esteem were measured before and after the manipulation. Participants also completed a candy taste rating task and ad lib consumption was surreptitiously measured. There was no main effect of condition on either psychological outcome variable or on grams consumed. Higher perceived sociocultural pressure to be thin was associated with a decrease in body esteem after reading the anti-obesity article only. Having a higher BMI was associated with greater candy intake in the word search condition. This trend was also apparent in the sun exposure condition, but not in the anti-obesity condition. Exposure to anti-obesity messages appears to decrease weight-related body esteem in women who already feel strong pressure to be thin, and may lead heavier women to suppress their food intake. Copyright © 2015. Published by Elsevier Ltd.

Maternal Use of Opioids During Pregnancy and Congenital Malformations: A Systematic Review

PubMed Central

Lind, Jennifer N.; Interrante, Julia D.; Ailes, Elizabeth C.; Gilboa, Suzanne M.; Khan, Sara; Frey, Meghan T.; Dawson, April L.; Honein, Margaret A.; Dowling, Nicole F.; Razzaghi, Hilda; Creanga, Andreea A.; Broussard, Cheryl S.

2017-01-01

CONTEXT Opioid use and abuse have increased dramatically in recent years, particularly among women. OBJECTIVES We conducted a systematic review to evaluate the association between prenatal opioid use and congenital malformations. DATA SOURCES We searched Medline and Embase for studies published from 1946 to 2016 and reviewed reference lists to identify additional relevant studies. STUDY SELECTION We included studies that were full-text journal articles and reported the results of original epidemiologic research on prenatal opioid exposure and congenital malformations. We assessed study eligibility in multiple phases using a standardized, duplicate review process. DATA EXTRACTION Data on study characteristics, opioid exposure, timing of exposure during pregnancy, congenital malformations (collectively or as individual subtypes), length of follow-up, and main findings were extracted from eligible studies. RESULTS Of the 68 studies that met our inclusion criteria, 46 had an unexposed comparison group; of those, 30 performed statistical tests to measure associations between maternal opioid use during pregnancy and congenital malformations. Seventeen of these (10 of 12 case-control and 7 of 18 cohort studies) documented statistically significant positive associations. Among the case-control studies, associations with oral clefts and ventricular septal defects/atrial septal defects were the most frequently reported specific malformations. Among the cohort studies, clubfoot was the most frequently reported specific malformation. LIMITATIONS Variabilities in study design, poor study quality, and weaknesses with outcome and exposure measurement. CONCLUSIONS Uncertainty remains regarding the teratogenicity of opioids; a careful assessment of risks and benefits is warranted when considering opioid treatment for women of reproductive age. PMID:28562278

Mobile phone exposure influences some erythrocytes parameters in vitro. A novel source of preanalytical variability?

PubMed

Danese, Elisa; Lippi, Giuseppe; Brocco, Giorgio; Montagnana, Martina; Salvagno, Gian Luca

2016-06-01

The effect of radiofrequency exposure on human health and health care equipment is a matter of ongoing debate. This study was planned to investigate the influence of radiofrequency (RF) waves emitted by a commercial mobile phone on red blood cells (RBC) in vitro. The study population consisted of 16 ostensibly healthy volunteers. Two whole blood specimens were collected from each volunteer. One sample was placed in a plastic rack, 1 cm distant from the chassis of a commercial mobile phone which was activated by a remote phone call lasting 30 min. The other blood sample was placed in another plastic rack, but was kept distant from any type of RF source. The main RBC parameters including RBC count, hematocrit (Ht), hemoglobin, mean corpuscular platelet volume (MPV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and RBC distribution width (RDW-CV) were assessed with an Advia 2120. The exposure of whole blood to the mobile phone call significantly increased Ht, hemoglobin, MCV and MCH, whereas the RBC count, MCHC and RDW-CV remained unchanged. A significant correlation was observed between variation of Ht and those of hemoglobin (p=0.008), MCV (p=0.009) or MCH (p=0.037), as well as between hemoglobin and MCV (p=0.048). Increased values were found in 13/16 (81%) samples for both Ht and hemoglobin, 14/16 (88%) samples for MCH and 16/16 (100%) samples for MCV. These results suggest that close mobile phone exposure may be an unappreciated and possibly underestimated cause of preanalytical bias in RBC testing.

Seroprevalence and occupational risk survey for Coxiella burnetii among exposed workers in Sicily, Southern Italy.

PubMed

Fenga, Concettina; Gangemi, Silvia; De Luca, Annamaria; Calimeri, Sebastiano; Lo Giudice, Daniela; Pugliese, Michela; Licitra, Francesca; Alibrandi, Angela; Costa, Chiara

2015-01-01

The aim of this survey was to assess the seroprevalence of antibodies against Coxiella burnetii (C. burnetii) in subjects at risk of exposure in Sicily, Southern Italy. Prevalence of IgG antibodies to C. burnetii phase II antigens was evaluated by ELISA in a group of 140 workers at risk of exposure (38 veterinarians, 38 slaughterhouse workers, 44 livestock handlers, 20 laboratory and technical personnel) included in a medical surveillance program and in 42 control subjects. Positive samples were classified as suggestive of prior exposure to C. burnetii. Antibodies against C. burnetii were detected in 88 out of 140 (62.9%) exposed workers and in 6 out of 42 (14.3%) subjects of the control group. The variables evaluated did not seem to have a significant effect on seropositivity to Coxiella with the exception of symptoms in the last 6 months preceding the survey. Our study demonstrated a high seroprevalence of C. burnetii in the group of exposed workers in comparison to non-exposed subjects of the control group. Clinical illness appears to be rare; nevertheless, physicians should consider Q fever in patients with compatible symptoms and occupational exposure to animals and their products. As aerosols represent the main route of infection in animals and humans, these workers are strongly advised to wear respiratory masks. In addition, occupational physicians should consider routine serologic evaluation and vaccination of occupationally exposed workers. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

[Occupational epidemiology: some methodological considerations].

PubMed

Alvear-Galindo, María Guadalupe; del Pilar Paz-Román, María

2006-01-01

During the last decade, occupational epidemiology has gained a great importance, not only because of the increase of pollutants and their noxiousness, but also because it has gone from the descriptive to the analytic level. The purpose of this work is to present what has been reported on epidemiological studies, different ways of characterizing and measuring occupational exposure, by emphasizing slants of exposure and selection measurement. In the reviewed studies, an interest in improving the exposure evaluation has been shown. The mainly reported measurement slants are the ways of measuring and classifying the exposure. The main designs were transversal with the use of matrixes to improve the evaluation of exposure. Conditions of hygiene and security were considered in order to control the quality of the information. This information was analyzed with different criteria. Some of the elements that hinder the research on occupational epidemiology are a mixed exposure, small populations, lack of exposure data, low levels of exposure and long periods of illness latency. Some breakthroughs in the strategies of epidemiological analysis and some other areas of knowledge have made possible a better understanding of work and health conditions of workers.

Tropical cyclone-related socio-economic losses in the western North Pacific region

NASA Astrophysics Data System (ADS)

Welker, C.; Faust, E.

2013-01-01

The western North Pacific (WNP) is the area of the world most frequently affected by tropical cyclones (TCs). However, little is known about the socio-economic impacts of TCs in this region, probably because of the limited relevant loss data. Here, loss data from Munich RE's NatCatSERVICE database is used, a high-quality and widely consulted database of natural disasters. In the country-level loss normalisation technique we apply, the original loss data are normalised to present-day exposure levels by using the respective country's nominal gross domestic product at purchasing power parity as a proxy for wealth. The main focus of our study is on the question of whether the decadal-scale TC variability observed in the Northwest Pacific region in recent decades can be shown to manifest itself economically in an associated variability in losses. It is shown that since 1980 the frequency of TC-related loss events in the WNP exhibited, apart from seasonal and interannual variations, interdecadal variability with a period of about 22 yr - driven primarily by corresponding variations of Northwest Pacific TCs. Compared to the long-term mean, the number of loss events was found to be higher (lower) by 14% (9%) in the positive (negative) phase of the decadal-scale WNP TC frequency variability. This was identified for the period 1980-2008 by applying a wavelet analysis technique. It was also possible to demonstrate the same low-frequency variability in normalised direct economic losses from TCs in the WNP region. The identification of possible physical mechanisms responsible for the observed decadal-scale Northwest Pacific TC variability will be the subject of future research, even if suggestions have already been made in earlier studies.

Variable X-Ray Absorption in the Mini-BAL QSO PG 1126-041

NASA Technical Reports Server (NTRS)

Giustini, M.; Cappi, M.; Chartas, G.; Dadina, M.; Eracleous, M.; Ponti, G.; Proga, D.; Tombesi, F.; Vignali, C.; Palumbo, G. G. C.

2011-01-01

Context. X-ray studies of AGN with powerful nuclear winds are important to constrain the physics of the inner accretion/ejection flow around SMBH, and to understand the impact of such winds on the AGN environment. Aims. Our main scientific goal is to constrain the properties of a variable outflowing absorber that is thought to be launched near the SMBH of the mini-BAL QSO PG 1126-041 using a multi-epoch observational campaign performed with XMM-Newton. Methods. We performed temporally resolved X-ray spectroscopy and simultaneous UV and X-ray photometry on the most complete set of observations and on the deepest X-ray exposure of a mini-BAL QSO to date. Results. We found complex X-ray spectral variability on time scales of both months and hours, best reproduced by means of variable massive ionized absorbers along the line of sight. As a consequence, the observed optical-to-X-ray spectral index is found to be variable with time. In the highest signal-to-noise observation we detected highly ionized X-ray absorbing material outflowing much faster (u(sub X) approx. 16 500 km/s) than the UV absorbing one (u(sub uv) approx. 5,000 km/s). This highly ionized absorber is found to be variable on very short (a few kiloseconds) time scales. Conclusions. Our findings are qualitatively consistent with line driven accretion disk winds scenarios. Our observations have opened the time-resolved X-ray spectral analysis field for mini-BAL QSOs; only with future deep studies will we be able to map the dynamics of the inner flow and understand the physics of AGN winds and their impact on the environment.

Effect of conjugal bereavement on mortality of the bereaved spouse in participants of the Renfrew/Paisley Study

PubMed Central

Hart, Carole L; Hole, David J; Lawlor, Debbie A; Smith, George Davey; Lever, Tony F

2007-01-01

Objectives To investigate how loss of a spouse affects mortality risk in the bereaved partner. Design and setting Prospective cohort study in Renfrew and Paisley in Scotland. Participants 4395 married couples aged 45–64 years when the study was carried out between 1972 and 1976. Methods The date of bereavement for the bereaved spouse was the date of death of his or her spouse. Bereavement could occur at any time during the follow‐up period, so it was considered as a time‐dependent exposure variable and the Cox proportional hazards model for time‐dependent variables was used. The relative rate (RR) of mortality was calculated for bereaved versus non‐bereaved spouses and adjusted for confounding variables. Main outcome measures Causes of death to 31 March 2004. Results Bereaved participants were at higher risk than non‐bereaved participants of dying from any cause (RR 1.27; 95% CI 1.2 to 1.35). These risks remained but were attenuated after adjustment for confounding variables. There were raised RRs for bereaved participants dying of cardiovascular disease, coronary heart disease, stroke, all cancer, lung cancer, smoking‐related cancer, and accidents or violence. After adjustment for confounding variables, RRs remained higher for bereaved participants for all these causes except for mortality from lung cancer. There was no strong statistical evidence that the increased risks of death associated with bereavement changed with time after bereavement. Conclusions Conjugal bereavement, in addition to existing risk factors, is related to mortality risk for major causes of death. PMID:17435215

Categorisation of built environment characteristics: the trouble with tertiles.

PubMed

Lamb, Karen E; White, Simon R

2015-02-15

In the analysis of the effect of built environment features on health, it is common for researchers to categorise built environment exposure variables based on arbitrary percentile cut-points, such as median or tertile splits. This arbitrary categorisation leads to a loss of information and a lack of comparability between studies since the choice of cut-point is based on the sample distribution. In this paper, we highlight the various drawbacks of adopting percentile categorisation of exposure variables. Using data from the SocioEconomic Status and Activity in Women (SESAW) study from Melbourne, Australia, we highlight alternative approaches which may be used instead of percentile categorisation in order to assess built environment effects on health. We discuss these approaches using an example which examines the association between the number of accessible supermarkets and body mass index. We show that alternative approaches to percentile categorisation, such as transformations of the exposure variable or factorial polynomials, can be implemented easily using standard statistical software packages. These procedures utilise all of the available information available in the data, avoiding a loss of power as experienced when categorisation is adopted.We argue that researchers should retain all available information by using the continuous exposure, adopting transformations where necessary.

Occupational exposure to motor exhaust in Stockholm, Sweden--different grouping strategies using variability in NO₂ to create homogenous groups.

PubMed

Lewné, Marie; Plato, Nils; Bellander, Tom; Alderling, Magnus; Gustavsson, Per

2011-01-01

The aim of the present study was to investigate the personal variability in occupational exposure to NO(2), as a marker of exposure to diesel exhaust, and to compare a statistical method of grouping workers in homogenous groups with a grouping performed by a qualified occupational hygienist. Forty-seven workers exposed to motor exhaust in their occupation were included. Personal measurements of NO(2) were performed with diffusive samplers over three full working shifts. The results from the measurements were analysed with a linear mixed effects model, taking both between and within-worker variability into consideration. The workers were divided into occupational groups in different ways in order to find a categorization, with maximal homogeneity in exposure in each group. We used (B)R(0.95) as an estimator of the between-worker variability. To study the effect of the divisions on the fit of the statistical model, we used the Akaike Information Criterion. The geometric mean for NO(2) for all 47 workers was 69 μg/m(3) and the between-worker variability (B)R(0.95) was 23.8. In six successive steps, the 47 workers were divided into up to eight groups, based on observed job characteristics. In the final grouping, seven groups were included with geometric means ranging from 32 μg/m(3) for outdoor workers, to 316 μg/m(3) for the most exposed group (tunnel construction workers). The (B)R(0.95) varied between 2.4 and 6.3. The within-worker variability (W)R(0.95) for the last division differed in the groups from 2.0 to 7.9. The Akaike Information Criterion decreased from 246, if all persons were included in one group, to 174 for the final grouping. The average level of NO(2) varied about 10 times between the different occupational groups, with the highest level for tunnel construction workers (316 μg/m(3)) and lowest for outdoor workers (32 μg/m(3)). For four of the seven groups the between-worker variability was higher than the within-worker variability. Copyright © 2010 Elsevier GmbH. All rights reserved.

Virtual reality exposure-based therapy for the treatment of post-traumatic stress disorder: a review of its efficacy, the adequacy of the treatment protocol, and its acceptability

PubMed Central

Botella, Cristina; Serrano, Berenice; Baños, Rosa M; Garcia-Palacios, Azucena

2015-01-01

Introduction The essential feature of post-traumatic stress disorder (PTSD) is the development of characteristic symptoms following exposure to one or more traumatic events. According to evidence-based intervention guidelines and empirical evidence, one of the most extensively researched and validated treatments for PTSD is prolonged exposure to traumatic events; however, exposure therapy can present some limitations. Virtual reality (VR) can help to improve prolonged exposure because it creates fictitious, safe, and controllable situations that can enhance emotional engagement and acceptance. Objective In addition to carrying out a review to evaluate the efficacy of VR exposure-based therapy (VR-EBT) for the treatment of PTSD, the aim of this study was to contribute to analyzing the use of VR-EBT by: first, evaluating the adequacy of psychological treatment protocols that use VR-EBT to treat PTSD; and second, analyzing the acceptability of VR-EBT. Method We performed a replica search with descriptors and databases used in two previous reviews and updated to April 2015. Next, we carried out an evaluation of the efficacy, adequacy, and acceptability of VR-EBT protocols. Results Results showed that VR-EBT was effective in the treatment of PTSD. The findings related to adequacy showed that not all studies using VR-EBT reported having followed the clinical guidelines for evidence-based interventions in the treatment of PTSD. Regarding acceptability, few studies evaluated this subject. However, the findings are very promising, and patients reported high acceptability and satisfaction with the inclusion of VR in the treatment of PTSD. Conclusion The main weaknesses identified in this review focus on the need for more controlled studies, the need to standardize treatment protocols using VR-EBT, and the need to include assessments of acceptability and related variables. Finally, this paper highlights some directions and future perspectives for using VR-EBT in PTSD treatment. PMID:26491332

Contributions of a Child’s Built, Natural, and Social Environments to Their General Cognitive Ability: A Systematic Scoping Review

DOE PAGES

Ruiz, Jazmin Del Carmen; Quackenboss, James J.; Tulve, Nicolle S.; ...

2016-02-03

The etiology of a child’s cognitive ability is complex, with research suggesting that it is not attributed to a single determinant or even a defined period of exposure. Rather, cognitive development is the product of cumulative interactions with the environment, both negative and positive, over the life course. The aim of this systematic scoping review was to collate evidence associated with children’s cognitive health, including inherent factors as well as chemical and non-chemical stressors from the built, natural, and social environments. Three databases were used to identify recent epidemiological studies (2003–2013) that examined exposure factors associated with general cognitive abilitymore » in children. Over 100 factors were evaluated from 258 eligible studies. We found that recent literature mainly assessed the hypothesized negative effects of either inherent factors or chemical exposures present in the physical environment. Prenatal growth, sleep health, lead and water pollutants showed consistent negative effects. Of the few studies that examined social stressors, results consistently showed cognitive development to be influenced by both positive and negative social interactions at home, in school or the community. Among behavioral factors related to diet and lifestyle choices of the mother, breastfeeding was the most studied, showing consistent positive associations with cognitive ability. There were mostly inconsistent results for both chemical and non-chemical stressors. The majority of studies utilized traditional exposure assessments, evaluating chemical and non-chemical stressors separately. Collective evidence from a limited number of studies revealed that cumulative exposure assessment that incorporates multiple chemical and non-chemical stressors over the life course may unravel the variability in effect on cognitive development and help explain the inconsistencies across studies. Here, future research examining the interactions of multiple stressors within a child’s total environment, depicting a more real-world exposure, will aid in understanding the cumulative effects associated with a child’s ability to learn.« less

Lessons learnt on biases and uncertainties in personal exposure measurement surveys of radiofrequency electromagnetic fields with exposimeters.

PubMed

Bolte, John F B

2016-09-01

Personal exposure measurements of radio frequency electromagnetic fields are important for epidemiological studies and developing prediction models. Minimizing biases and uncertainties and handling spatial and temporal variability are important aspects of these measurements. This paper reviews the lessons learnt from testing the different types of exposimeters and from personal exposure measurement surveys performed between 2005 and 2015. Applying them will improve the comparability and ranking of exposure levels for different microenvironments, activities or (groups of) people, such that epidemiological studies are better capable of finding potential weak correlations with health effects. Over 20 papers have been published on how to prevent biases and minimize uncertainties due to: mechanical errors; design of hardware and software filters; anisotropy; and influence of the body. A number of biases can be corrected for by determining multiplicative correction factors. In addition a good protocol on how to wear the exposimeter, a sufficiently small sampling interval and sufficiently long measurement duration will minimize biases. Corrections to biases are possible for: non-detects through detection limit, erroneous manufacturer calibration and temporal drift. Corrections not deemed necessary, because no significant biases have been observed, are: linearity in response and resolution. Corrections difficult to perform after measurements are for: modulation/duty cycle sensitivity; out of band response aka cross talk; temperature and humidity sensitivity. Corrections not possible to perform after measurements are for: multiple signals detection in one band; flatness of response within a frequency band; anisotropy to waves of different elevation angle. An analysis of 20 microenvironmental surveys showed that early studies using exposimeters with logarithmic detectors, overestimated exposure to signals with bursts, such as in uplink signals from mobile phones and WiFi appliances. Further, the possible corrections for biases have not been fully applied. The main findings are that if the biases are not corrected for, the actual exposure will on average be underestimated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Contributions of a Child’s Built, Natural, and Social Environments to Their General Cognitive Ability: A Systematic Scoping Review

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

Ruiz, Jazmin Del Carmen; Quackenboss, James J.; Tulve, Nicolle S.

The etiology of a child’s cognitive ability is complex, with research suggesting that it is not attributed to a single determinant or even a defined period of exposure. Rather, cognitive development is the product of cumulative interactions with the environment, both negative and positive, over the life course. The aim of this systematic scoping review was to collate evidence associated with children’s cognitive health, including inherent factors as well as chemical and non-chemical stressors from the built, natural, and social environments. Three databases were used to identify recent epidemiological studies (2003–2013) that examined exposure factors associated with general cognitive abilitymore » in children. Over 100 factors were evaluated from 258 eligible studies. We found that recent literature mainly assessed the hypothesized negative effects of either inherent factors or chemical exposures present in the physical environment. Prenatal growth, sleep health, lead and water pollutants showed consistent negative effects. Of the few studies that examined social stressors, results consistently showed cognitive development to be influenced by both positive and negative social interactions at home, in school or the community. Among behavioral factors related to diet and lifestyle choices of the mother, breastfeeding was the most studied, showing consistent positive associations with cognitive ability. There were mostly inconsistent results for both chemical and non-chemical stressors. The majority of studies utilized traditional exposure assessments, evaluating chemical and non-chemical stressors separately. Collective evidence from a limited number of studies revealed that cumulative exposure assessment that incorporates multiple chemical and non-chemical stressors over the life course may unravel the variability in effect on cognitive development and help explain the inconsistencies across studies. Here, future research examining the interactions of multiple stressors within a child’s total environment, depicting a more real-world exposure, will aid in understanding the cumulative effects associated with a child’s ability to learn.« less

Contributions of a Child’s Built, Natural, and Social Environments to Their General Cognitive Ability: A Systematic Scoping Review

PubMed Central

Ruiz, Jazmin Del Carmen; Quackenboss, James J.; Tulve, Nicolle S.

2016-01-01

The etiology of a child’s cognitive ability is complex, with research suggesting that it is not attributed to a single determinant or even a defined period of exposure. Rather, cognitive development is the product of cumulative interactions with the environment, both negative and positive, over the life course. The aim of this systematic scoping review was to collate evidence associated with children’s cognitive health, including inherent factors as well as chemical and non-chemical stressors from the built, natural, and social environments. Three databases were used to identify recent epidemiological studies (2003–2013) that examined exposure factors associated with general cognitive ability in children. Over 100 factors were evaluated from 258 eligible studies. We found that recent literature mainly assessed the hypothesized negative effects of either inherent factors or chemical exposures present in the physical environment. Prenatal growth, sleep health, lead and water pollutants showed consistent negative effects. Of the few studies that examined social stressors, results consistently showed cognitive development to be influenced by both positive and negative social interactions at home, in school or the community. Among behavioral factors related to diet and lifestyle choices of the mother, breastfeeding was the most studied, showing consistent positive associations with cognitive ability. There were mostly inconsistent results for both chemical and non-chemical stressors. The majority of studies utilized traditional exposure assessments, evaluating chemical and non-chemical stressors separately. Collective evidence from a limited number of studies revealed that cumulative exposure assessment that incorporates multiple chemical and non-chemical stressors over the life course may unravel the variability in effect on cognitive development and help explain the inconsistencies across studies. Future research examining the interactions of multiple stressors within a child’s total environment, depicting a more real-world exposure, will aid in understanding the cumulative effects associated with a child’s ability to learn. PMID:26840411

Exposure to a community-level HIV prevention intervention: who gets the message.

PubMed

Walls, C T; Lauby, J; Lavelle, K; Derby, T; Bond, L

1998-08-01

As part of the evaluation of a community-level HIV prevention program for women, this study examined predictors of exposure to print media and community outreach and assessed the relationship between exposure to the intervention and condom use behavior. Data from interviews with 479 women randomly selected from the intervention community in 1995 and 1996 were examined. Analysis of demographic and risk characteristics were conducted to identify predictors of exposure to the project's HIV prevention messages. Additionally, logistic regression analyses were conducted to examine the effects of intervention exposure on condom use, controlling for factors related to exposure. The results revealed that the print media campaign reached the largest number of women. However, women at highest risk did not have high rates of exposure to print media, but had greater exposure to outreach. Exposure to print media had an effect on increased communication with a main partner about condom use, but was not significantly related to condom use last time had sex. There were no significant main effects for exposure to outreach on condom use behavior. An important finding of this analysis was that each intervention strategy was successful in reaching a different portion of the target population and that exposure had differential effects on the condom use behavior of particular segments of the target population.

Personal exposure to pesticide among workers engaged in pesticide container recycling operations.

PubMed

Guidotti, T L; Yoshida, K; Clough, V

1994-12-01

Pesticide container handling operations in western Canada were examined to determine the exposure of workers to residual pesticide in sorting, metal-container crushing, metal-container shredding, plastic-container shredding, metal washing, and metal melting. Environmental exposure monitoring and biological monitoring were applied, including measurement of pesticide deposition density on outer clothing (test coveralls and other protective wear), deposition on fabric and gauze patches under the outer clothing, inhalation of airborne pesticide residues, dislodgement of pesticide residues by hand washing, and pre- and postexposure urinary excretion of pesticide (2,4-D). Exposure levels were highly variable; some variability was accounted for by work practices or lapses in protection. The highest levels of exposure were observed for metal washing, metal crushing, and metal shredding; sorting and plastic shredding were intermediate, and metal melting was associated with very little exposure. Urinary 2,4-D excretion, as an indicator of internal dose, correlated most closely with exposure by the inhalation route, and both were highest for metal washing and shredding. Deposition of pesticide on garments was highest for metal crushing. Melting of washed metal does not appear to present a significant hazard of exposure. Recommendations are proposed for the protection of workers emphasizing health and safety guidelines, worker education, personal hygiene, exposure and health monitoring, and record-keeping, and specific recommendations for each process. These recommendations apply to all pesticide container recycling operations except melting of washed metal containers.

Exposure-effect relations between aircraft and road traffic noise exposure at school and reading comprehension: the RANCH project.

PubMed

Clark, Charlotte; Martin, Rocio; van Kempen, Elise; Alfred, Tamuno; Head, Jenny; Davies, Hugh W; Haines, Mary M; Lopez Barrio, Isabel; Matheson, Mark; Stansfeld, Stephen A

2006-01-01

Transport noise is an increasingly prominent feature of the urban environment, making noise pollution an important environmental public health issue. This paper reports on the 2001-2003 RANCH project, the first cross-national epidemiologic study known to examine exposure-effect relations between aircraft and road traffic noise exposure and reading comprehension. Participants were 2,010 children aged 9-10 years from 89 schools around Amsterdam Schiphol, Madrid Barajas, and London Heathrow airports. Data from The Netherlands, Spain, and the United Kingdom were pooled and analyzed using multilevel modeling. Aircraft noise exposure at school was linearly associated with impaired reading comprehension; the association was maintained after adjustment for socioeconomic variables (beta = -0.008, p = 0.012), aircraft noise annoyance, and other cognitive abilities (episodic memory, working memory, and sustained attention). Aircraft noise exposure at home was highly correlated with aircraft noise exposure at school and demonstrated a similar linear association with impaired reading comprehension. Road traffic noise exposure at school was not associated with reading comprehension in either the absence or the presence of aircraft noise (beta = 0.003, p = 0.509; beta = 0.002, p = 0.540, respectively). Findings were consistent across the three countries, which varied with respect to a range of socioeconomic and environmental variables, thus offering robust evidence of a direct exposure-effect relation between aircraft noise and reading comprehension.