Nasopharyngeal Case-Control Study

Cancer.gov

A case-control study conducted in Taiwan between 1991-1994 among approximately 1,000 individuals to examine the role of viral, environmental, and genetic factors associated with the development of nasopharyngeal carcinoma

A case-control study: occupational cooking and the risk of uveal melanoma

PubMed Central

2010-01-01

Background A European-wide population based case-control study (European rare cancer study) undertaken in nine European countries examined risk factors for uveal melanoma. They found a positive association between cooks and the risk of uveal melanoma. In our study we examine whether cooks or people who worked in cook related jobs have an increased uveal melanoma risk. Methods We conducted a case-control study during 2002 and 2005. Overall, 1653 eligible subjects (age range: 20-74 years, living in Germany) participated. Interviews were conducted with 459 incident uveal melanoma cases, 827 population controls, 180 ophthalmologist controls and 187 sibling controls. Data on occupational exposure were obtained from a self-administered postal questionnaire and a computer-assisted telephone interview. We used conditional logistic regression to estimate odds ratios adjusting for the matching factors. Results Overall, we did not observe an increased risk of uveal melanoma among people who worked as cooks or who worked in cook related jobs. When we restricted the source population of our study to the population of the Federal State of Northrhine-Westphalia, we observed an increased risk among subjects who were categorized as cooks in the cases-control analysis. Conclusion Our results are in conflict with former results of the European rare cancer study. Considering the rarity of the disease laboratory in vitro studies of human uveal melanoma cell lines should be done to analyze potential exposure risk factors like radiation from microwaves, strong light from incandescent ovens, or infrared radiation. PMID:20969762

Case-control Studies on the Effectiveness of Breast Cancer Screening: Insights from the UK Age Trial.

PubMed

van der Waal, Daniëlle; Broeders, Mireille J M; Verbeek, André L M; Duffy, Stephen W; Moss, Sue M

2015-07-01

Ongoing breast cancer screening programs can only be evaluated using observational study designs. Most studies have observed a reduction in breast cancer mortality, but design differences appear to have resulted in different estimates. Direct comparison of case-control and trial analyses gives more insight into this variation. Here, we performed case-control analyses within the randomized UK Age Trial. The Age Trial assessed the effect of screening on breast cancer mortality in women ages 40-49 years. In our approach, case subjects were defined as breast cancer deaths between trial entry (1991-1997) and 2004. Women were ages 39-41 years at entry. For every case subject, five control subjects were selected. All case subjects were included in analyses of screening invitation (356 case subjects, 1,780 controls), whereas analyses of attendance were restricted to women invited to screening (105 case subjects, 525 age-matched controls). Odds ratios (OR) were estimated with conditional logistic regression. We used and compared two methods to correct for self-selection bias. Screening invitation resulted in a breast cancer mortality reduction of 17% (95% confidence interval [CI]: -36%, +6%), similar to trial results. Different exposure definitions and self-selection adjustments influenced the observed breast cancer mortality reduction. Depending on the method, "ever screened" appeared to be associated with a small reduction (OR: 0.86, 95% CI: 0.40, 1.89) or no reduction (OR: 1.02, 95% CI: 0.48, 2.14) using the two methods of correction. Recent attendance resulted in an adjusted mortality reduction of 36% (95% CI: -69%, +31%) or 45% (95% CI: -71%, +5%). Observational studies, and particularly case-control studies, are an important monitoring tool for breast cancer screening programs. The focus should be on diminishing bias in observational studies and gaining a better understanding of the influence of study design on estimates of mortality reduction.

Designing Case-Control Studies: Decisions About the Controls

PubMed Central

Hodge, Susan E.; Subaran, Ryan L.; Weissman, Myrna M.; Fyer, Abby J.

2014-01-01

The authors quantified, first, the effect of misclassified controls (i.e., individuals who are affected with the disease under study but who are classified as controls) on the ability of a case-control study to detect an association between a disease and a genetic marker, and second, the effect of leaving misclassified controls in the study, as opposed to removing them (thus decreasing sample size). The authors developed an informativeness measure of a study’s ability to identify real differences between cases and controls. They then examined this measure’s behavior when there are no misclassified controls, when there are misclassified controls, and when there were misclassified controls but they have been removed from the study. The results show that if, for example, 10% of controls are misclassified, the study’s informativeness is reduced to approximately 81% of what it would have been in a sample with no misclassified controls, whereas if these misclassified controls are removed from the study, the informativeness is only reduced to about 90%, despite the reduced sample size. If 25% are misclassified, those figures become approximately 56% and 75%, respectively. Thus, leaving the misclassified controls in the control sample is worse than removing them altogether. Finally, the authors illustrate how insufficient power is not necessarily circumvented by having an unlimited number of controls. The formulas provided by the authors enable investigators to make rational decisions about removing misclassified controls or leaving them in. PMID:22854929

Leucocytes telomere length and breast cancer risk/ susceptibility: A case-control study.

PubMed

Pavanello, Sofia; Varesco, Liliana; Gismondi, Viviana; Bruzzi, Paolo; Bolognesi, Claudia

2018-01-01

Telomere length in peripheral blood leukocytes (PBL-TL) was proposed as a biomarker of cancer risk. Recent scientific evidence suggested PBL-TL plays a diverse role in different cancers. Inconsistent results were obtained on PBL-TL in relation to breast cancer risk and specifically to the presence of BRCA1 and BRCA2 mutations. The aim of the present case-control study was to analyse the correlation between family history of breast cancer or presence of a BRCA mutation and PBL-TL in the hypothesis that TL is a modifier of cancer risk. PBL-TL was measured using the real-time quantitative PCR method in DNA for 142 cases and 239 controls. All the women enrolled were characterized for cancer family history. A subgroup of 48 women were classified for the presence of a BRCA mutation. PBL-TL were summarized as means and standard deviations, and compared by standard analysis of variance. A multivariable Generalised Linear Model was fitted to the data with PBL-TL as the dependent variable, case/control status and presence of a BRCA/VUS mutation as factors, and age in 4 strata as a covariate. Age was significantly associated with decreasing PBL-TL in controls (p = 0.01), but not in BC cases. The telomere length is shorter in cases than in controls after adjusting for age. No effect on PBL-TL of BMI, smoke nor of the most common risk factors for breast cancer was observed. No association between PBL-TL and family history was detected both in BC cases and controls. In the multivariate model, no association was observed between BRCA mutation and decreased PBL-TL. A statistically significant interaction (p = 0.031) between case-control status and a BRCA-mutation/VUS was observed, but no effect was detected for the interaction of cancer status and BRCA or VUS. Our study fails to provide support to the hypothesis that PBL-TL is associated with the risk of hereditary BC, or that is a marker of inherited mutations in BRCA genes.

Leucocytes telomere length and breast cancer risk/ susceptibility: A case-control study

PubMed Central

Pavanello, Sofia; Varesco, Liliana; Gismondi, Viviana; Bruzzi, Paolo

2018-01-01

Background Telomere length in peripheral blood leukocytes (PBL-TL) was proposed as a biomarker of cancer risk. Recent scientific evidence suggested PBL-TL plays a diverse role in different cancers. Inconsistent results were obtained on PBL-TL in relation to breast cancer risk and specifically to the presence of BRCA1 and BRCA2 mutations. The aim of the present case-control study was to analyse the correlation between family history of breast cancer or presence of a BRCA mutation and PBL-TL in the hypothesis that TL is a modifier of cancer risk. Methods PBL-TL was measured using the real-time quantitative PCR method in DNA for 142 cases and 239 controls. All the women enrolled were characterized for cancer family history. A subgroup of 48 women were classified for the presence of a BRCA mutation. PBL-TL were summarized as means and standard deviations, and compared by standard analysis of variance. A multivariable Generalised Linear Model was fitted to the data with PBL-TL as the dependent variable, case/control status and presence of a BRCA/VUS mutation as factors, and age in 4 strata as a covariate. Results Age was significantly associated with decreasing PBL-TL in controls (p = 0.01), but not in BC cases. The telomere length is shorter in cases than in controls after adjusting for age. No effect on PBL-TL of BMI, smoke nor of the most common risk factors for breast cancer was observed. No association between PBL-TL and family history was detected both in BC cases and controls. In the multivariate model, no association was observed between BRCA mutation and decreased PBL-TL. A statistically significant interaction (p = 0.031) between case-control status and a BRCA-mutation/VUS was observed, but no effect was detected for the interaction of cancer status and BRCA or VUS. Conclusion Our study fails to provide support to the hypothesis that PBL-TL is associated with the risk of hereditary BC, or that is a marker of inherited mutations in BRCA genes. PMID:29782524

Recall bias in melanoma risk factors and measurement error effects: a nested case-control study within the Norwegian Women and Cancer Study.

PubMed

Parr, Christine L; Hjartåker, Anette; Laake, Petter; Lund, Eiliv; Veierød, Marit B

2009-02-01

Case-control studies of melanoma have the potential for recall bias after much public information about the relation with ultraviolet radiation. Recall bias has been investigated in few studies and only for some risk factors. A nested case-control study of recall bias was conducted in 2004 within the Norwegian Women and Cancer Study: 208 melanoma cases and 2,080 matched controls were invited. Data were analyzed for 162 cases (response, 78%) and 1,242 controls (response, 77%). Questionnaire responses to several host factors and ultraviolet exposures collected at enrollment in 1991-1997 and in 2004 were compared stratified on case-control status. Shifts in responses were observed among both cases and controls, but a shift in cases was observed only for skin color after chronic sun exposure, and a larger shift in cases was observed for nevi. Weighted kappa was lower for cases than for controls for most age intervals of sunburn, sunbathing vacations, and solarium use. Differences in odds ratio estimates of melanoma based on prospective and retrospective measurements indicate measurement error that is difficult to characterize. The authors conclude that indications of recall bias were found in this sample of Norwegian women, but that the results were inconsistent for the different exposures.

Suspected survivor bias in case-control studies: stratify on survival time and use a negative control.

PubMed

van Rein, Nienke; Cannegieter, Suzanne C; Rosendaal, Frits R; Reitsma, Pieter H; Lijfering, Willem M

2014-02-01

Selection bias in case-control studies occurs when control selection is inappropriate. However, selection bias due to improper case sampling is less well recognized. We describe how to recognize survivor bias (i.e., selection on exposed cases) and illustrate this with an example study. A case-control study was used to analyze the effect of statins on major bleedings during treatment with vitamin K antagonists. A total of 110 patients who experienced such bleedings were included 18-1,018 days after the bleeding complication and matched to 220 controls. A protective association of major bleeding for exposure to statins (odds ratio [OR]: 0.56; 95% confidence interval: 0.29-1.08) was found, which did not become stronger after adjustment for confounding factors. These observations lead us to suspect survivor bias. To identify this bias, results were stratified on time between bleeding event and inclusion, and repeated for a negative control (an exposure not related to survival): blood group non-O. The ORs for exposure to statins increased gradually to 1.37 with shorter time between outcome and inclusion, whereas ORs for the negative control remained constant, confirming our hypothesis. We recommend the presented method to check for overoptimistic results, that is, survivor bias in case-control studies. Copyright © 2014 Elsevier Inc. All rights reserved.

The effectiveness of the mumps component of the MMR vaccine: a case control study.

PubMed

Harling, Richard; White, Joanne M; Ramsay, Mary E; Macsween, Karen F; van den Bosch, Corry

2005-07-01

In 1998/1999, an outbreak of mumps occurred among children of a religious community in North East London. A case control study was conducted to assess the effectiveness of the mumps component of the MMR vaccine. One hundred and sixty-one cases of mumps were identified and 192 controls were selected. Fifty-one percent of cases and 77% of controls had a history at least one MMR vaccination. The observed effectiveness of any MMR vaccination adjusted for age, sex and general practice was 69% (95% CI: 41-84%). This is consistent with the results of other observational studies of mumps containing vaccines, but lower than the immunogenicity of mumps vaccines reported by clinical trials. This discrepancy is because observational studies tend to underestimate vaccine effectiveness, and because immunogenicity is not necessarily an accurate biological marker of vaccine effectiveness. Two doses of vaccine were more effective (88% (95% CI: 62-96%)) than a single dose (64% (95% CI: 40-78%)). The current two-dose vaccination programme remains the best method for controlling mumps infection in the community.

Vitamin C Intake and Pancreatic Cancer Risk: A Meta-Analysis of Published Case-Control and Cohort Studies.

PubMed

Hua, Yong-Fei; Wang, Gao-Qing; Jiang, Wei; Huang, Jing; Chen, Guo-Chong; Lu, Cai-De

2016-01-01

Observational studies inconsistently reported the relationship between vitamin C intake and risk of pancreatic cancer. We conducted a meta-analysis of published case-control and cohort studies to quantify the association. Potentially eligible studies were found on PubMed and EMBASE databases through May 31, 2015. A random-effects model was assigned to compute summary point estimates with corresponding 95% confidence intervals (CIs). Subgroup and meta-regression analyses were also performed to explore sources of heterogeneity. Our final analyses included 20 observational studies comprising nearly 5 thousand cases of pancreatic cancer. When comparing the highest with the lowest categories of vitamin C intake, the summary odds ratio/relative risk for case-control studies (14 studies), cohort studies (6 studies) and all studies combined was 0.58 (95% CI: 0.52-0.66), 0.93 (95% CI: 0.78-1.11) and 0.66 (95% CI: 0.58-0.75), respectively. The difference in the findings between case-control and cohort studies was statistically significant (P < .001). Possible publication bias was shown in the meta-analysis of case-control studies. There is insufficient evidence to conclude any relationship between vitamin C intake and risk of pancreatic cancer. The strong inverse association observed in case-control studies may be affected by biases (eg, recall and selection biases) that particularly affect case-control studies and/or potential publication bias. Future prospective studies of vitamin C intake and pancreatic cancer are needed.

Reducing selection bias in case-control studies from rare disease registries.

PubMed

Cole, J Alexander; Taylor, John S; Hangartner, Thomas N; Weinreb, Neal J; Mistry, Pramod K; Khan, Aneal

2011-09-12

In clinical research of rare diseases, where small patient numbers and disease heterogeneity limit study design options, registries are a valuable resource for demographic and outcome information. However, in contrast to prospective, randomized clinical trials, the observational design of registries is prone to introduce selection bias and negatively impact the validity of data analyses. The objective of the study was to demonstrate the utility of case-control matching and the risk-set method in order to control bias in data from a rare disease registry. Data from the International Collaborative Gaucher Group (ICGG) Gaucher Registry were used as an example. A case-control matching analysis using the risk-set method was conducted to identify two groups of patients with type 1 Gaucher disease in the ICGG Gaucher Registry: patients with avascular osteonecrosis (AVN) and those without AVN. The frequency distributions of gender, decade of birth, treatment status, and splenectomy status were presented for cases and controls before and after matching. Odds ratios (and 95% confidence intervals) were calculated for each variable before and after matching. The application of case-control matching methodology results in cohorts of cases (i.e., patients with AVN) and controls (i.e., patients without AVN) who have comparable distributions for four common parameters used in subject selection: gender, year of birth (age), treatment status, and splenectomy status. Matching resulted in odds ratios of approximately 1.00, indicating no bias. We demonstrated bias in case-control selection in subjects from a prototype rare disease registry and used case-control matching to minimize this bias. Therefore, this approach appears useful to study cohorts of heterogeneous patients in rare disease registries.

[Child abuse in Tlaxcala: a case-control study].

PubMed

Herrada-Huidobro, A; Nazar-Beutelspacher, A; Cassaball-Núñez, M; Vega-Ramos, R; Nava-Cruz, C B

1992-01-01

A longitudinal, retrospective and descriptive study about child abuse was carried out in the Hospitals of the Tlaxcala Secretariat of Health, Mexico. The information was obtained from hospitalized children's charts between January first and November 30, 1991. The charts included were those belonging to zero to 14 year old children with injuries, poisoning, and II-III degrees of malnutrition. Four child-abuse criteria were established: physical, sexual, non organic malnutrition and mixed (physical and non organic malnutrition). Two control groups were defined. Different patterns were observed between accidental and non accidental injuries, malnutrition and poisoning among the case and the control groups. The study provides useful information for the integral diagnosis of child abuse in hospitalized children.

Anal signs of child sexual abuse: a case-control study.

PubMed

Hobbs, Christopher J; Wright, Charlotte M

2014-05-27

There is uncertainty about the nature and specificity of physical signs following anal child sexual abuse. The study investigates the extent to which physical findings discriminate between children with and without a history of anal abuse. Retrospective case note review in a paediatric forensic unit. all eligible cases from 1990 to 2007 alleging anal abuse. all children examined anally from 1998 to 2007 with possible physical abuse or neglect with no identified concern regarding sexual abuse. Fisher's exact test (two-tailed) was performed to ascertain the significance of differences for individual signs between cases and controls. To explore the potential role of confounding, logistic regression was used to produce odds ratios adjusted for age and gender. A total of 184 cases (105 boys, 79 girls), average age 98.5 months (range 26 to 179) were compared with 179 controls (94 boys, 85 girls) average age 83.7 months (range 35-193). Of the cases 136 (74%) had one or more signs described in anal abuse, compared to 29 (16%) controls. 79 (43%) cases and 2 (1.1%) controls had >1 sign. Reflex anal dilatation (RAD) and venous congestion were seen in 22% and 36% of cases but <1% of controls (likelihood ratios (LR) 40, 60 respectively), anal fissure in 14% cases and 1.1% controls (LR 13), anal laxity in 27% cases and 3% controls (LR 10).Novel signs seen significantly more commonly in cases were anal fold changes, swelling and twitching. Erythema, swelling and fold changes were seen most commonly within 7 days of last reported contact; RAD, laxity, venous congestion, fissure and twitching were observed up to 6 months after the alleged assault. Anal findings are more common in children alleging anal abuse than in those presenting with physical abuse or neglect with no concern about sexual abuse. Multiple signs are rare in controls and support disclosed anal abuse.

Workplace Education Initiative: Case Studies and Observations.

ERIC Educational Resources Information Center

Astrein, Bruce; And Others

Seven workplace education projects funded in the first year of the Massachusetts Workplace Education Initiative are reported. This report includes both general observations and specific information in case studies of the projects. Overall information is provided on students served, the importance of partnerships, the emphasis on…

SABRE observations of Pi2 pulsations: case studies

NASA Astrophysics Data System (ADS)

Bradshaw, E. G.; Lester, M.

1997-01-01

The characteristics of substorm-associated Pi2 pulsations observed by the SABRE coherent radar system during three separate case studies are presented. The SABRE field of view is well positioned to observe the differences between the auroral zone pulsation signature and that observed at mid-latitudes. During the first case study the SABRE field of view is initially in the eastward electrojet, equatorward and to the west of the substorm-enhanced electrojet current. As the interval progresses, the western, upward field-aligned current of the substorm current wedge moves westward across the longitudes of the radar field of view. The westward motion of the wedge is apparent in the spatial and temporal signatures of the associated Pi2 pulsation spectra and polarisation sense. During the second case study, the complex field-aligned and ionospheric currents associated with the pulsation generation region move equatorward into the SABRE field of view and then poleward out of it again after the third pulsation in the series. The spectral content of the four pulsations during the interval indicate different auroral zone and mid-latitude signatures. The final case study is from a period of low magnetic activity when SABRE observes a Pi2 pulsation signature from regions equatorward of the enhanced substorm currents. There is an apparent mode change between the signature observed by SABRE in the ionosphere and that on the ground by magnetometers at latitudes slightly equatorward of the radar field of view. The observations are discussed in terms of published theories of the generation mechanisms for this type of pulsation. Different signatures are observed by SABRE depending on the level of magnetic activity and the position of the SABRE field of view relative to the pulsation generation region. A twin source model for Pi2 pulsation generation provides the clearest explanation of the signatures observed Acknowledgements. The authors are grateful to Prof. D. J. Southwood

Evaluating the use of friend or family controls in epidemiologic case-control studies.

PubMed

Zhong, Charlie; Cockburn, Myles; Cozen, Wendy; Voutsinas, Jenna; Lacey, James V; Luo, Jianning; Sullivan-Halley, Jane; Bernstein, Leslie; Wang, Sophia S

2017-02-01

Traditional methodologies for identifying and recruiting controls in epidemiologic case-control studies, such as random digit dialing or neighborhood walk, suffer from declining response rates. Here, we revisit the feasibility and comparability of using alternative sources of controls, specifically friend and family controls. We recruited from a recently completed case-control study of non-Hodgkin lymphoma (NHL) among women in Los Angeles County where controls from the parent study were ascertained by neighborhood walk. We calculated participation rates and compared questionnaire responses between the friend/family controls and the original matched controls from the parent study. Of the 182 NHL case patients contacted, 111 (61%) agreed to participate in our feasibility study. 70 (63%) provided contact information for potential friend and/or family member controls. We were able to successfully contact and recruit a friend/family member for 92% of the case patients. This represented 46 friend controls and 54 family controls. Family controls significantly differed from original matched controls by sex and household income. Other characteristics were similar between friend controls and the original study's neighborhood controls. The apparent comparability of neighborhood controls to friend and family controls among respondents in this study suggests that these alternative methods of control identification can serve as a complementary source of eligible controls in epidemiologic case-control studies. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

From randomized controlled trials to observational studies.

PubMed

Silverman, Stuart L

2009-02-01

Randomized controlled trials are considered the gold standard in the hierarchy of research designs for evaluating the efficacy and safety of a treatment intervention. However, their results can have limited applicability to patients in clinical settings. Observational studies using large health care databases can complement findings from randomized controlled trials by assessing treatment effectiveness in patients encountered in day-to-day clinical practice. Results from these designs can expand upon outcomes of randomized controlled trials because of the use of larger and more diverse patient populations with common comorbidities and longer follow-up periods. Furthermore, well-designed observational studies can identify clinically important differences among therapeutic options and provide data on long-term drug effectiveness and safety.

Effectiveness of inactivated quadrivalent influenza vaccine in the 2015/2016 season as assessed in both a test-negative case-control study design and a traditional case-control study design.

PubMed

Kimiya, Takahisa; Shinjoh, Masayoshi; Anzo, Makoto; Takahashi, Hiroki; Sekiguchi, Shinichiro; Sugaya, Norio; Takahashi, Takao

2018-04-21

Both traditional case-control studies (TCCSs) and test-negative case-control studies (TNCCSs) are commonly used to assess influenza vaccine effectiveness (VE). To compensate for the fact that observational studies are susceptible to bias, we combined both methods to assess VE in one geographical area during the 2015/2016 season, when influenza A (H1N1)pdm was dominant. Our TNCCS covered 331 children aged 6 months to 15 years who visited our hospital with fever, including 182 with influenza, and our TCCS covered 812 pediatric outpatients aged 6 months to 15 years, including 214 with influenza. Influenza infection and vaccination history were reviewed, and VE was calculated as (1 - odds ratio) × 100. In the TNCCS, VE against influenza A was 68% (95% CI 47-81) overall, and 70% (48-83) for those given two doses; against influenza B, VE was 37% (- 12-64) overall and 49% (2-74) for two doses. In the TCCS, VE against influenza A was 44% (15-63) overall and 44% (13-64) for two doses, and VE against influenza B was 24% (- 19-52) overall and 41% (3-64) for two doses. Both studies confirmed significant VE against influenza A, significant two-dose VE against influenza B, and better two-dose VE than one-dose VE. What is Known: • Influenza vaccine effectiveness (VE) varies from year to year. • Observational studies are conventionally used for VE assessment. However, they are inherently susceptible to bias and confounding. What is New: • This is the first report of influenza VE assessment using more than one observational study and performed in a specific area during the same season. • VE estimates obtained in our traditional case-control study were lower than those in our test-negative case-control study, but both studies found significant VE against influenza.

Case Studies in Modelling, Control in Food Processes.

PubMed

Glassey, J; Barone, A; Montague, G A; Sabou, V

This chapter discusses the importance of modelling and control in increasing food process efficiency and ensuring product quality. Various approaches to both modelling and control in food processing are set in the context of the specific challenges in this industrial sector and latest developments in each area are discussed. Three industrial case studies are used to demonstrate the benefits of advanced measurement, modelling and control in food processes. The first case study illustrates the use of knowledge elicitation from expert operators in the process for the manufacture of potato chips (French fries) and the consequent improvements in process control to increase the consistency of the resulting product. The second case study highlights the economic benefits of tighter control of an important process parameter, moisture content, in potato crisp (chips) manufacture. The final case study describes the use of NIR spectroscopy in ensuring effective mixing of dry multicomponent mixtures and pastes. Practical implementation tips and infrastructure requirements are also discussed.

Case-control study of amyotrophic lateral sclerosis

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

Deapen, D.M.; Henderson, B.E.

1986-05-01

The authors conducted a study of 518 amyotrophic lateral sclerosis patients identified between 1977 and 1979 and 518 controls to investigate putative risk factors for this disease. Occupations at risk of electrical exposure were reported more often by patients (odds ratio (OR) = 3.8, 95% confidence interval (CI) = 1.4-13.0) as were electrical shocks producing unconsciousness (OR = 2.8, 95% CI = 1.0-9.9). Although an overall excess of physical trauma associated with unconsciousness was observed in the amyotrophic lateral sclerosis patients (OR = 1.6, 95% CI = 1.0-2.4), the effect was inversely associated with duration of the unconscious episodes, suggestingmore » an effect of recall bias. Only slight differences were found for surgical traumata to the nervous system. Parkinsonism was reported more often among first degree relatives of cases (OR = 2.7, 95% CI = 1.1-7.6). The frequencies of prior poliomyelitis or other central nervous system diseases were similar for patients and controls. Occupational exposure to selected toxic substances was similar for patients and controls except for the manufacture of plastics (OR = 3.7, 95% CI = 1.0-20.5), although few details of these exposures were provided. No differences in occupations with exposure to animal skins or hides were observed.« less

The lack of selection bias in a snowball sampled case-control study on drug abuse.

PubMed

Lopes, C S; Rodrigues, L C; Sichieri, R

1996-12-01

Friend controls in matched case-control studies can be a potential source of bias based on the assumption that friends are more likely to share exposure factors. This study evaluates the role of selection bias in a case-control study that used the snowball sampling method based on friendship for the selection of cases and controls. The cases selected fro the study were drug abusers located in the community. Exposure was defined by the presence of at least one psychiatric diagnosis. Psychiatric and drug abuse/dependence diagnoses were made according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria. Cases and controls were matched on sex, age and friendship. The measurement of selection bias was made through the comparison of the proportion of exposed controls selected by exposed cases (p1) with the proportion of exposed controls selected by unexposed cases (p2). If p1 = p2 then, selection bias should not occur. The observed distribution of the 185 matched pairs having at least one psychiatric disorder showed a p1 value of 0.52 and a p2 value of 0.51, indicating no selection bias in this study. Our findings support the idea that the use of friend controls can produce a valid basis for a case-control study.

Case control study of neuroblastoma in west-Germany after the Chernobyl accident.

PubMed

Michaelis, J; Haaf, H G; Zöllner, J; Kaatsch, P; Krummenauer, F; Berthold, F

1996-01-01

To explore possible causes of a 1988 incidence peak of infant neuroblastoma in west German regions which were contaminated with more than 6000 Bq/m2 Cs137 from the Chernobyl accident. The primary working hypothesis was that parents of the diseased children had been contaminated by an excessive intake of locally produced food, especially mushrooms or deer. Case control study with 1:2 (cases:controls) matching. Data were collected from the children's parents by questionnaires and telephone interviews. Nation-wide study (former FRG) based on the German Childhood Cancer Registry. Cases born in 1988 and reported with a neuroblastoma to the registry until March 1992. Population-based healthy controls, matched for age, sex and residence at time of diagnosis. The working hypothesis could not be confirmed by the study, because the parents of cases tended to eat less locally grown food than the parents of controls (RR = 0.63, 95% CI:0.20-1.97). Possible influence factors which previously have been described to be associated with neuroblastoma incidence could not be confirmed by the study. Parental exposure to herbicides and pesticides was associated with the occurrence of neuroblastoma (RR = 4.2, 95% CI:1.4-12.9). Neuroblastoma stage distribution in the contaminated regions was shifted towards lower stages as compared to the less contaminated regions and previous age cohorts. The study does not show additional evidence that the observed increase in neuroblastoma incidence might have been caused by exposure to fallout from the Chernobyl accident. The observed shift towards lower clinical stages may rather indicate increased diagnostic awareness. The association between neuroblastoma and parental exposure with herbicides and pesticides resulted from an extensive exploratory data analysis and needs to be confirmed in further studies.

Pilot case-control study of paediatric falls from windows.

PubMed

Johnston, Brian D; Quistberg, D Alexander; Shandro, Jamie R; Partridge, Rebecca L; Song, Hyun Rae; Ebel, Beth E

2011-12-01

Unintentional falls from windows are an important cause of paediatric morbidity. There have been no controlled studies to identify modifiable environmental risk factors for window falls in young children. The authors have piloted a case-control study to test procedures for case identification, subject enrolment, and environmental data collection. Case windows were identified when a child 0-9 years old presented for care after a fall from that window. Control windows were identified (1) from the child's home and (2) from the home of an age- and gender-matched child seeking care for an injury diagnosis not related to a window fall. Study staff visited enrolled homes to collect window measurements and conduct window screen performance tests. The authors enrolled and collected data on 18 case windows, 18 in-home controls, and 14 matched community controls. Six potential community controls were contacted for every one enrolled. Families who completed the home visit viewed study procedures positively. Case windows were more likely than community controls to be horizontal sliders (100% vs 50%), to have deeper sills (6.28 vs 4.31 inches), to be higher above the exterior surface (183 vs 82 inches), and to have screens that failed below a threshold derived from the static pressure of a 3-year-old leaning against the mesh (60.0% vs 16.7%). Case windows varied very little from in-home controls. Case-control methodology can be used to study risk factors for paediatric falls from windows. Recruitment of community controls is challenging but essential, because in-home controls tend to be over-matched on important variables. A home visit allows direct measurement of window type, height, sill depth, and screen performance. These variables should all be investigated in subsequent, larger studies covering major housing markets.

Nested case-control studies: should one break the matching?

PubMed

Borgan, Ørnulf; Keogh, Ruth

2015-10-01

In a nested case-control study, controls are selected for each case from the individuals who are at risk at the time at which the case occurs. We say that the controls are matched on study time. To adjust for possible confounding, it is common to match on other variables as well. The standard analysis of nested case-control data is based on a partial likelihood which compares the covariates of each case to those of its matched controls. It has been suggested that one may break the matching of nested case-control data and analyse them as case-cohort data using an inverse probability weighted (IPW) pseudo likelihood. Further, when some covariates are available for all individuals in the cohort, multiple imputation (MI) makes it possible to use all available data in the cohort. In the paper we review the standard method and the IPW and MI approaches, and compare their performance using simulations that cover a range of scenarios, including one and two endpoints.

25-hydroxyvitamin D and breast cancer, colorectal cancer, and colorectal adenomas: case-control versus nested case-control studies.

PubMed

Grant, William B

2015-02-01

Existing literature includes concerns regarding reliability of case-control studies of breast cancer incidence with respect to 25-hydroxyvitamin D (25(OH)D) concentrations. For breast cancer, only case-control studies consistently find inverse correlations between 25(OH)D and breast cancer. However, for colorectal cancer, nested case-control studies find significant inverse correlations with respect to 25(OH)D concentrations at baseline for mean follow-up times of 7 years. This is a review of results currently existing in literature. I provide evidence that 25(OH)D concentration values are only useful for short follow-up times for breast cancer since it develops rapidly. To support the robust nature of breast cancer case-control studies, I show that results from 11 studies from seven countries align in a robust power-law fit to the odds ratio versus mean 25(OH)D concentrations. Case-control studies of breast cancer incidence rates provide reliable results. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Assessing different measures of population-level vaccine protection using a case-control study.

PubMed

Ali, Mohammad; You, Young Ae; Kanungo, Suman; Manna, Byomkesh; Deen, Jacqueline L; Lopez, Anna Lena; Wierzba, Thomas F; Bhattacharya, Sujit K; Sur, Dipika; Clemens, John D

2015-11-27

Case-control studies have not been examined for their utility in assessing population-level vaccine protection in individually randomized trials. We used the data of a randomized, placebo-controlled trial of a cholera vaccine to compare the results of case-control analyses with those of cohort analyses. Cases of cholera were selected from the trial population followed for three years following dosing. For each case, we selected 4 age-matched controls who had not developed cholera. For each case and control, GIS was used to calculate vaccine coverage of individuals in a surrounding "virtual" cluster. Specific selection strategies were used to evaluate the vaccine protective effects. 66,900 out of 108,389 individuals received two doses of the assigned regimen. For direct protection among subjects in low vaccine coverage clusters, we observed 78% (95% CI: 47-91%) protection in a cohort analysis and 84% (95% CI: 60-94%) in case-control analysis after adjusting for confounding factors. Using our GIS-based approach, estimated indirect protection was 52% (95% CI: 10-74%) in cohort and 76% (95% CI: 47-89%) in case control analysis. Estimates of total and overall effectiveness were similar for cohort and case-control analyses. The findings show that case-control analyses of individually randomized vaccine trials may be used to evaluate direct as well as population-level vaccine protection. Copyright © 2015. Published by Elsevier Ltd.

Participation in population-based case-control studies: does the observed decline vary by socio-economic status?

PubMed

Mazloum, Marie; Bailey, Helen D; Heiden, Tamika; Armstrong, Bruce K; de Klerk, Nicholas; Milne, Elizabeth

2012-05-01

An Australian study of childhood leukaemia (Aus-ALL) previously reported that control participation was positively associated with socio-economic status (SES). A similar study of childhood brain tumours (Aus-CBT) was carried out 4 years later, and this paper compares control participation and its relationship with SES in the two studies. To assess the representativeness of controls in terms of SES, the addresses of controls were linked to Australian Bureau of Statistics Census 2006 Collection Districts (CDs), and hence to area-based indices of SES. Independent sample t-tests and chi-squared tests were used to compare the SES indices of CDs where Aus-CBT controls lived with those where Aus-ALL controls lived and with those of all CDs where Australian families lived. The overall percentage of eligible families who agreed to participate was lower in Aus-CBT (53.9%) than in Aus-ALL (70.3%). Control families in both studies were of higher SES than the general population, while the distribution of SES among recruited controls was similar in both studies. These findings provide some reassurance that the observed decline in research participation over time may not be associated with an increasingly unrepresentative participant population. © 2012 Blackwell Publishing Ltd.

Comparative study of control selection in a national population-based case-control study: Estimating risk of smoking on cancer deaths in Chinese men.

PubMed

Jiang, Jingmei; Liu, Boqi; Nasca, Philip C; Han, Wei; Zou, Xiaonong; Zeng, Xianjia; Tian, Xiaobing; Wu, Yanping; Zhao, Ping; Li, Junyao

2009-10-28

To assess the validation of a novel control selection design by comparing the consistency between the new design and a routine design in a large case-control study that was incorporated into a nationwide mortality survey in China. A nationwide mortality study was conducted during 1989-1991. Surviving spouses or other relatives of all adults who died during 1986-1988 provided detailed information about their own as well as the deceased person's smoking history. In this study, 130,079 males who died of various smoking-related cancers at age 35 or over were taken as cases, while 103,248 male surviving spouses (same age range with cases) of women who died during the same period and 49,331 males who died from causes other than those related to smoking were used as control group 1 and control group 2, respectively. Consistency in the results when comparing cases with each of the control groups was assessed. Consistency in the results was observed in the analyses using different control groups although cancer deaths varied with region and age. Equivalence could be ascertained using a 15% criterion in most cancer deaths which had high death rates in urban areas, but they were uncertain for most cancers in rural areas irrespective of whether the hypothesis testing showed significant differences or not. Sex-matched living spouse control design as an alternative control selection for a case-control study is valid and feasible, and the basic principles of the equivalence study are also supported by epidemiological survey data.

Role of survivor bias in pancreatic cancer case-control studies.

PubMed

Hu, Zhen-Huan; Connett, John E; Yuan, Jian-Min; Anderson, Kristin E

2016-01-01

The purpose of this study was to evaluate the impact of survivor bias on pancreatic cancer case-control studies. The authors constructed five case-loss scenarios based on the Iowa Women's Health Study cohort to reflect how case recruitment in population-based studies varies by case survival time. Risk factors for disease incidence included smoking, body mass index (BMI), waist circumference, diabetes, and alcohol consumption. Odds ratios (ORs) were estimated by conditional logistic regression and quantitatively compared by the interactions between risk factors and 3-month survival time. Additionally, Kaplan-Meier estimates for overall survival were compared within the subset cohort of pancreatic cancer cases. BMI and waist circumference showed a significant inverse relationship with survival time. Decreasing trends in ORs for BMI and waist circumference were observed with increasing case survival time. The interaction between BMI and survival time based on a cutpoint of 3 months was significant (P < .01) as was the interaction between waist circumference and survival time (P < .01). The findings suggested that case losses could result in survivor bias causing underestimated odds ratios for both BMI and waist circumference, whereas other risk factors were not significantly affected by case losses. Copyright © 2016 Elsevier Inc. All rights reserved.

Dermatoglyphic patterns in dementia of the Alzheimer type: a case-control study.

PubMed Central

Berr, C; Okra-Podrabinek, N; Feteanu, D; Taurand, S; Hervy, M P; Forette, F; Piette, F; Sebag-Lanoe, R; Alperovitch, A

1992-01-01

STUDY OBJECTIVE--The aim was to compare digital and palmar dermatoglyphics in subjects with dementia of Alzheimer type and in mentally healthy elderly controls. DESIGN--This design was a case-control study. SETTING--The study was carried out in geriatric units and retirement communities in the Paris area. PARTICIPANTS--Cases were women with clinically diagnosed Alzheimer type dementia according to DSM III-R criteria (n = 82), mainly with late onset of the disease. Controls were women aged 85 years or older without cognitive deterioration (n = 76). MEASUREMENTS AND MAIN RESULTS--Finger and palm prints obtained from both hands by the classical ink method were examined. Fingerprints were classified into four types of figures. On palms, palmar flexion creases, palmar axial triradii, true patterns of the hypothenar area, and main line terminations were described. Examinations were performed by two examiners blind to the subjects's diagnostic category. For the different patterns studied, no major differences between dementia patients and elderly controls were found. Nor was there evidence of high frequencies of features commonly observed in Down's syndrome (trisomy 21), which have previously, though sporadically, been reported. CONCLUSIONS--On one of the largest samples of Alzheimer dementia patients studied, and with evaluation blind to diagnosis, no evidence has been found that particular dermatoglyphic patterns occur like those observed in Down's syndrome, a disease which is related to dementia of the Alzheimer type. PMID:1479321

Persistent hyperphagia in acquired brain injury; an observational case study of patients receiving inpatient rehabilitation.

PubMed

Rowell, Arleen M; Faruqui, Rafey A

2010-01-01

Morbid hunger or persistent hyperphagia is a relatively rare but potentially life threatening complication of acquired brain injury (ABI). This paper presents findings from an observational case study of patients with hyperphagia receiving inpatient neurobehavioural rehabilitation following their acquired brain injury. The case study has utilized dietetic and medical records of identified patients to confirm the persistent and serious nature of this presentation in order to extract important management principles. The findings confirmed that hyperphagia or morbid hunger posed potentially life-threatening health risks to the patient, primarily around weight control and fluid balance, and risks of aggression towards professional and family carers. Pharmacological or behaviour modification interventions were only partially successful in management of this presentation. The study identified a high need for environmental and cue exposure control in management of this condition.

Observational evidence and strength of evidence domains: case examples

PubMed Central

2014-01-01

Background Systematic reviews of healthcare interventions most often focus on randomized controlled trials (RCTs). However, certain circumstances warrant consideration of observational evidence, and such studies are increasingly being included as evidence in systematic reviews. Methods To illustrate the use of observational evidence, we present case examples of systematic reviews in which observational evidence was considered as well as case examples of individual observational studies, and how they demonstrate various strength of evidence domains in accordance with current Agency for Healthcare Research and Quality (AHRQ) Evidence-based Practice Center (EPC) methods guidance. Results In the presented examples, observational evidence is used when RCTs are infeasible or raise ethical concerns, lack generalizability, or provide insufficient data. Individual study case examples highlight how observational evidence may fulfill required strength of evidence domains, such as study limitations (reduced risk of selection, detection, performance, and attrition); directness; consistency; precision; and reporting bias (publication, selective outcome reporting, and selective analysis reporting), as well as additional domains of dose-response association, plausible confounding that would decrease the observed effect, and strength of association (magnitude of effect). Conclusions The cases highlighted in this paper demonstrate how observational studies may provide moderate to (rarely) high strength evidence in systematic reviews. PMID:24758494

Study design options in evaluating gene-environment interactions: practical considerations for a planned case-control study of pediatric leukemia.

PubMed

Goodman, Michael; Dana Flanders, W

2007-04-01

We compare methodological approaches for evaluating gene-environment interaction using a planned study of pediatric leukemia as a practical example. We considered three design options: a full case-control study (Option I), a case-only study (Option II), and a partial case-control study (Option III), in which information on controls is limited to environmental exposure only. For each design option we determined its ability to measure the main effects of environmental factor E and genetic factor G, and the interaction between E and G. Using the leukemia study example, we calculated sample sizes required to detect and odds ratio (OR) of 2.0 for E alone, an OR of 10 for G alone and an interaction G x E of 3. Option I allows measuring both main effects and interaction, but requires a total sample size of 1,500 cases and 1,500 controls. Option II allows measuring only interaction, but requires just 121 cases. Option III allows calculating the main effect of E, and interaction, but not the main effect of G, and requires a total of 156 cases and 133 controls. In this case, the partial case-control study (Option III) appears to be more efficient with respect to its ability to answer the research questions for the amount of resources required. The design options considered in this example are not limited to observational epidemiology and may be applicable in studies of pharmacogenomics, survivorship, and other areas of pediatric ALL research.

Zinc Intake and Risk of Prostate Cancer: Case-Control Study and Meta-Analysis.

PubMed

Mahmoud, Abeer M; Al-Alem, Umaima; Dabbous, Firas; Ali, Mohamed M; Batai, Ken; Shah, Ebony; Kittles, Rick A

2016-01-01

Zinc is an essential dietary element that has been implicated in the pathogenesis of prostate cancer, a cancer that disproportionately affects men of African descent. Studies assessing the association of zinc intake and prostate cancer have yielded inconsistent results. Furthermore, very little is known about the relationship between zinc intake and prostate cancer among African Americans. We examined the association between self-reported zinc intake and prostate cancer in a hospital-based case-control study of African Americans. We then compared our results with previous studies by performing a meta-analysis to summarize the evidence regarding the association between zinc and prostate cancer. Newly diagnosed African American men with histologically confirmed prostate cancer (n = 127) and controls (n = 81) were recruited from an urban academic urology clinic in Washington, DC. Controls had higher zinc intake, with a mean of 14 mg/day versus 11 mg/day for cases. We observed a non-significant, non-linear increase in prostate cancer when comparing tertiles of zinc intake (OR <6.5 vs 6.5-12.5mg/day 1.8, 95% CI: 0.6,5.6; OR <6.5 vs >12.5mg/day 1.3, 95% CI: 0.2,6.5). The pooled estimate from 17 studies (including 3 cohorts, 2 nested case-control, 11 case-control studies, and 1 randomized clinical trial, with a total of 111,199 participants and 11,689 cases of prostate cancer) was 1.07hi vs lo 95% CI: 0.98-1.16. Using a dose-response meta-analysis, we observed a non-linear trend in the relationship between zinc intake and prostate cancer (p for nonlinearity = 0.0022). This is the first study to examine the relationship between zinc intake in black men and risk of prostate cancer and systematically evaluate available epidemiologic evidence about the magnitude of the relationship between zinc intake and prostate cancer. Despite of the lower intake of zinc by prostate cancer patients, our meta-analysis indicated that there is no evidence for an association between zinc

Role of matching in case-control studies of antimicrobial resistance.

PubMed

Cerceo, Elizabeth; Lautenbach, Ebbing; Linkin, Darren R; Bilker, Warren B; Lee, Ingi

2009-05-01

Of 57 case-control studies of antimicrobial resistance, matching was used in 23 (40%). Matched variables differed substantially across studies. Of these 23 matched case-control studies, 12 (52%) justified the use of matching, and 9 (39%) noted the strengths or limitations of this approach. Analysis that accounted for matching was performed in only 52% of the case-control studies.

Dermatoglyphic patterns in dementia of the Alzheimer type: a case-control study.

PubMed

Berr, C; Okra-Podrabinek, N; Feteanu, D; Taurand, S; Hervy, M P; Forette, F; Piette, F; Sebag-Lanoe, R; Alperovitch, A

1992-10-01

The aim was to compare digital and palmar dermatoglyphics in subjects with dementia of Alzheimer type and in mentally healthy elderly controls. This design was a case-control study. The study was carried out in geriatric units and retirement communities in the Paris area. Cases were women with clinically diagnosed Alzheimer type dementia according to DSM III-R criteria (n = 82), mainly with late onset of the disease. Controls were women aged 85 years or older without cognitive deterioration (n = 76). Finger and palm prints obtained from both hands by the classical ink method were examined. Fingerprints were classified into four types of figures. On palms, palmar flexion creases, palmar axial triradii, true patterns of the hypothenar area, and main line terminations were described. Examinations were performed by two examiners blind to the subjects's diagnostic category. For the different patterns studied, no major differences between dementia patients and elderly controls were found. Nor was there evidence of high frequencies of features commonly observed in Down's syndrome (trisomy 21), which have previously, though sporadically, been reported. On one of the largest samples of Alzheimer dementia patients studied, and with evaluation blind to diagnosis, no evidence has been found that particular dermatoglyphic patterns occur like those observed in Down's syndrome, a disease which is related to dementia of the Alzheimer type.

Valid statistical inference methods for a case-control study with missing data.

PubMed

Tian, Guo-Liang; Zhang, Chi; Jiang, Xuejun

2018-04-01

The main objective of this paper is to derive the valid sampling distribution of the observed counts in a case-control study with missing data under the assumption of missing at random by employing the conditional sampling method and the mechanism augmentation method. The proposed sampling distribution, called the case-control sampling distribution, can be used to calculate the standard errors of the maximum likelihood estimates of parameters via the Fisher information matrix and to generate independent samples for constructing small-sample bootstrap confidence intervals. Theoretical comparisons of the new case-control sampling distribution with two existing sampling distributions exhibit a large difference. Simulations are conducted to investigate the influence of the three different sampling distributions on statistical inferences. One finding is that the conclusion by the Wald test for testing independency under the two existing sampling distributions could be completely different (even contradictory) from the Wald test for testing the equality of the success probabilities in control/case groups under the proposed distribution. A real cervical cancer data set is used to illustrate the proposed statistical methods.

Calculation of controllability and observability matrices for special case of continuous-time multi-order fractional systems.

PubMed

Hassanzadeh, Iman; Tabatabaei, Mohammad

2017-03-28

In this paper, controllability and observability matrices for pseudo upper or lower triangular multi-order fractional systems are derived. It is demonstrated that these systems are controllable and observable if and only if their controllability and observability matrices are full rank. In other words, the rank of these matrices should be equal to the inner dimension of their corresponding state space realizations. To reduce the computational complexities, these matrices are converted to simplified matrices with smaller dimensions. Numerical examples are provided to show the usefulness of the mentioned matrices for controllability and observability analysis of this case of multi-order fractional systems. These examples clarify that the duality concept is not necessarily true for these special systems. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Epidemiological risk factors in microscopic colitis: a prospective case-control study.

PubMed

Fernández-Bañares, Fernando; de Sousa, Monia R; Salas, Antonio; Beltrán, Belén; Piqueras, Marta; Iglesias, Eva; Gisbert, Javier P; Lobo, Beatriz; Puig-Diví, Valentí; García-Planella, Esther; Ordás, Ingrid; Andreu, Montserrat; Calvo, Marta; Montoro, Miguel; Esteve, Maria; Viver, Josep M

2013-02-01

The cause of collagenous colitis (CC) and lymphocytic colitis (LC) is unknown and epidemiological risk factors for CC and LC are not well studied. The aim was to evaluate in a case-control study epidemiological risk factors for CC and LC. In all, 120 patients with CC, 70 with CL, and 128 controls were included. For all cases and controls information was prospectively recorded. A binary logistic regression analysis was performed separately for CC and LC. Independent associations observed with the diagnosis of CC were: current smoking (odds ratio [OR], 2.4), history of polyarthritis (OR, 20.8), and consumption of lansoprazole (OR, 6.4), low-dose aspirin (OR, 3.8), beta-blockers (OR, 3.6), and angiotensin II receptor antagonists (OR 0.20). In the case of LC they were: current smoking (OR, 3.8), associated autoimmune diseases (OR, 8), and consumption of sertraline (OR, 17.5), omeprazole (OR 2.7), low-dose aspirin (OR, 4.7), and oral antidiabetic drugs (OR, 0.14). The consumption of drugs, current smoking, and associated autoimmune diseases were independently associated with the risk of microscopic colitis.

Mobile phone use and the risk for malignant brain tumors: a case-control study on deceased cases and controls.

PubMed

Hardell, Lennart; Carlberg, Michael; Hansson Mild, Kjell

2010-08-01

We investigated the use of mobile or cordless phones and the risk for malignant brain tumors in a group of deceased cases. Most previous studies have either left out deceased cases of brain tumors or matched them to living controls and therefore a study matching deceased cases to deceased controls is warranted. Recall error is one issue since it has been claimed that increased risks reported in some studies could be due to cases blaming mobile phones as a cause of the disease. This should be of less importance for deceased cases and if cancer controls are used. In this study brain tumor cases aged 20-80 years diagnosed during 1997-2003 that had died before inclusion in our previous studies on the same topic were included. Two control groups were used: one with controls that had died from another type of cancer than brain tumor and one with controls that had died from other diseases. Exposure was assessed by a questionnaire sent to the next-of-kin for both cases and controls. Replies were obtained for 346 (75%) cases, 343 (74%) cancer controls and 276 (60%) controls with other diseases. Use of mobile phones gave an increased risk, highest in the >10 years' latency group yielding odds ratio (OR) = 2.4, and 95% confidence interval (CI) = 1.4-4.1. The risk increased with cumulative number of lifetime hours for use, and was highest in the >2,000 h group (OR = 3.4, 95% CI = 1.6-7.1). No clear association was found for use of cordless phones, although OR = 1.7, 95% CI = 0.8-3.4 was found in the group with >2,000 h of cumulative use. This investigation confirmed our previous results of an association between mobile phone use and malignant brain tumors. Copyright 2010 S. Karger AG, Basel.

Occupation and thyroid cancer: a population-based case-control study in Connecticut

PubMed Central

Ba, Yue; Huang, Huang; Lerro, Catherine C.; Li, Shuzhen; Zhao, Nan; Li, Anqi; Ma, Shuangge; Udelsman, Robert; Zhang, Yawei

2016-01-01

Objective The study aims to explore the associations between various occupations and thyroid cancer risk. Methods A population-based case-control study involving 462 histologically confirmed incident cases and 498 controls was conducted in Connecticut in 2010–2011. Results A significantly increased risk of thyroid cancer, particularly papillary microcarcinoma, was observed for those working as the healthcare practitioners and technical workers, health diagnosing and treating practitioners and registered nurses. Those working in building and grounds cleaning, maintenance occupations, pest control, retail sales, and customer service also had increased risk for papillary thyroid cancer. Subjects who worked as cooks, janitors, cleaners, and customer service representatives were at an increased risk of papillary thyroid cancer with tumor size >1 cm. Conclusions Certain occupations were associated with an increased risk of thyroid cancer, with some tumor size and subtype specificity. PMID:26949881

Occupational risk factors for mycosis fungoides: a European multicenter case-control study.

PubMed

Morales-Suárez-Varela, Maria M; Olsen, Jorn; Johansen, Preben; Kaerlev, Linda; Guénel, Pascal; Arveux, Patrick; Wingren, Gun; Hardell, Lennart; Ahrens, Wolfgang; Stang, Andreas; Llopis, Agustin; Merletti, Franco; Aurrekoetxea, Juan Jose; Masala, Giovanna

2004-03-01

Mycosis fungoides (MF) is a rare disease with an unknown etiology. Its distribution suggests that occupational exposures may play a role. In the present study, we searched for occupational factors associated with MF. A European multicenter case-control study on seven rare cancers, including MF, was conducted from 1995 to 1997. Patients between 35 and 69 years of age diagnosed with MF (n = 134) were identified and their diagnoses were checked by a reference pathologist who classified 83 cases as definitive, 35 cases as possible, and 16 cases as not histologically verified. Of the 118 histologically verified cases, 104 were interviewed, of which 76 were definitive cases. As controls, we selected population controls and colon cancer controls to serve all seven case groups. Altogether, 833 colon cancer controls and 2071 population controls were interviewed. The response rate was 91.5% for cases (76 of the 83 definitive cases), and 66.6% for controls. A high risk of MF for men was observed in the industries of other non-metallic mineral products (Odds Ratio [OR] 5.3, 95% confidence interval [CI] = 1.7-16.2) and of wholesale trade (OR 3.6, 95% CI = 1.3-10.5). A high risk was found for female employees in the sector of pulp paper manufacture (OR 14.4, 95% CI = 2.2-95.1). The male occupations with the highest risks were glass formers, potters, and ceramics workers (OR 17.9, 95% CI = 5.4-59.4) and technical salesmen (OR 8.6, 95% CI = 2.4-30.8). For women, the occupations associated with the highest risks were government executives (OR 4.8, 95% CI = 1.0-22.6) and railway and road vehicles loaders (OR 3.9, 95% CI = 1.0-14.0). The results suggest that some occupational factors are associated with MF. Working as glass formers, pottery, and ceramics workers carried the highest risk, and these findings deserve further attention and replication. Females working in the paper and pulp industries may also be exposed to carcinogens of relevance to MF.

Population versus hospital controls for case-control studies on cancers in Chinese hospitals

PubMed Central

2011-01-01

Background Correct control selection is crucial to the internal validity of case-control studies. Little information exists on differences between population and hospital controls in case-control studies on cancers in Chinese hospital setting. Methods We conducted three parallel case-control studies on leukemia, breast and colorectal cancers in China between 2009 and 2010, using population and hospital controls to separately match 540 incident cases by age, gender and residency at a 1:1 ratio. Demographic and lifestyle factors were measured using a validated questionnaire in face-to-face interview. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained using conditional logistic regression analyses. Results The two control groups had closely similar exposure distributions of 15 out of 16 factors, with the only exception being that hospital controls were less likely to have a BMI ≥ 25 (OR = 0.71, 95% CI: 0.54, 0.93). For exposure of green tea drinking, the adjusted ORs (95% CIs) comparing green tealeaves intake ≥ 1000 grams annually with non-drinkers were 0.51 (0.31, 0.83) and 0.21 (0.27, 0.74) for three cancers combined, 0.06 (0.01, 0.61) and 0.07 (0.01, 0.47) for breast cancer, 0.52 (0.29, 0.94) and 0.45 (0.25, 0.82) for colorectal cancer, 0.65 (0.08, 5.63) and 0.57 (0.07, 4.79) for leukemia using hospital and population controls respectively. Conclusions The study found that hospital controls were comparable with population controls for most demographic characteristics and lifestyle factors measured, but there was a slight difference between the two control groups. Hospital outpatients provide a satisfactory control group in hospital-based case-control study in the Chinese hospital setting. PMID:22171783

Population versus hospital controls for case-control studies on cancers in Chinese hospitals.

PubMed

Li, Lin; Zhang, Min; Holman, D'Arcy

2011-12-15

Correct control selection is crucial to the internal validity of case-control studies. Little information exists on differences between population and hospital controls in case-control studies on cancers in Chinese hospital setting. We conducted three parallel case-control studies on leukemia, breast and colorectal cancers in China between 2009 and 2010, using population and hospital controls to separately match 540 incident cases by age, gender and residency at a 1:1 ratio. Demographic and lifestyle factors were measured using a validated questionnaire in face-to-face interview. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained using conditional logistic regression analyses. The two control groups had closely similar exposure distributions of 15 out of 16 factors, with the only exception being that hospital controls were less likely to have a BMI ≥ 25 (OR = 0.71, 95% CI: 0.54, 0.93). For exposure of green tea drinking, the adjusted ORs (95% CIs) comparing green tealeaves intake ≥ 1000 grams annually with non-drinkers were 0.51 (0.31, 0.83) and 0.21 (0.27, 0.74) for three cancers combined, 0.06 (0.01, 0.61) and 0.07 (0.01, 0.47) for breast cancer, 0.52 (0.29, 0.94) and 0.45 (0.25, 0.82) for colorectal cancer, 0.65 (0.08, 5.63) and 0.57 (0.07, 4.79) for leukemia using hospital and population controls respectively. The study found that hospital controls were comparable with population controls for most demographic characteristics and lifestyle factors measured, but there was a slight difference between the two control groups. Hospital outpatients provide a satisfactory control group in hospital-based case-control study in the Chinese hospital setting.

Organizing pneumonia and occupational and environmental risk factors: a case-control study.

PubMed

Jobard, Stéphanie; Chaigne, Benjamin; Marchand-Adam, Sylvain; Lasfargues, Gérard; Diot, Elisabeth

2017-11-01

A single-center case-control study was carried out to investigate the relationship between occupational and environmental exposure and organizing pneumonia (OP). Thirty-seven cases of OP, including 25 cases of cryptogenic OP, and 111 controls were included. Occupational exposure was assessed retrospectively by an industrial hygienist and an occupational physician, through semi-quantitative estimates of exposure. An exposure score was calculated for each subject, based on probability, intensity, daily frequency, and duration of exposure for each period of employment. The final cumulative exposure score was obtained by summing exposure scores for all periods of employment. Significant associations with all-cause OP were observed for exposure to tetrachloroethylene (OR 13.33, CI 95% 1.44-123.5) and silica (OR 6.61, CI 95% 1.16-37.71). A significant association with cryptogenic OP was observed only for tetrachloroethylene (OR 31.6, CI 95% 1.64-610.8). No associations were found for environmental exposure. Despite its low statistical power, this work suggests that occupational risk factors could be involved in OP.

[Risk factors associated with trigger finger. Case-control study].

PubMed

De la Parra-Márquez, Miguel Leonardo; Tamez-Cavazos, Roberto; Zertuche-Cedillo, Luis; Martínez-Pérez, Juan José; Velasco-Rodríguez, Víctor; Cisneros-Pérez, Vicente

2008-01-01

We undertook this study to identify risk factors in our population associated with trigger finger. The study was conducted at the Instituto Mexicano del Seguro Social, UMAE 21, Monterrey, Nuevo Leon, Mexico. This was a case-control, retrospective, and observational study. There were 250 patients in each group. For cases, patients who were operated on for trigger finger from March 2006 to August 2006 were included. Controls included patients admitted to the Emergency Department with hand injuries that fulfilled the selection criteria. Risk factors analyzed were diabetes, hypertension, smoking, sex, age, weight, and 19 different occupations. Mean age of the cases was 52 years (SE +/- 14.19 years) with a median and mode of 53 years. The right hand was the most common with the middle, thumb, ring, index and little fingers, respectively. A significant statistical relationship was found: females (OR 7.57, 95% CI 5.07-11.31); diabetes (OR 3.72, 95% CI 2.43-5.70); obesity (OR 1.49, 95% CI 1.02-2.19). With regard to occupation, a statistical relationship was found: homemaker (OR 2.44, 95% CI 1.62-3.69); seamstress (OR 4.8, 95% CI 1.3-21.6); and secretary (OR 2.74, 95% CI 1.38-5.52). Trigger finger is a common pathology in our population and is more frequent in women >53 years old. It may be related to diabetes, body mass index (obesity) and certain occupations such as secretary, seamstress and homemaker.

Case-control study of renal cell carcinoma in relation to occupation, smoking, and alcohol consumption

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

Brownson, R.C.

1988-05-01

A case-control study based on data from a cancer registry was conducted to evaluate the effects of smoking, alcohol use, and occupation on renal cell cancer risk. Information was obtained for 326 male and female cases and 978 age- and sex-matched controls. Elevated risks were identified for cigarette smokers and for men employed as truck drivers. No relationship between alcohol consumption and renal cancer was observed.

Association between bullous pemphigoid and neurologic diseases: a case-control study.

PubMed

Casas-de-la-Asunción, E; Ruano-Ruiz, J; Rodríguez-Martín, A M; Vélez García-Nieto, A; Moreno-Giménez, J C

2014-11-01

In the past 10 years, bullous pemphigoid has been associated with other comorbidities and neurologic and psychiatric conditions in particular. Case series, small case-control studies, and large population-based studies in different Asian populations, mainland Europe, and the United Kingdom have confirmed this association. However, no data are available for the Spanish population. This was an observational, retrospective, case-control study with 1:2 matching. Fifty-four patients with bullous pemphigoid were selected. We compared the percentage of patients in each group with concurrent neurologic conditions, ischemic heart disease, diabetes, chronic obstructive pulmonary disease, and solid tumors using univariate logistic regression. An association model was constructed with conditional multiple logistic regression. The case group had a significantly higher percentage of patients with cerebrovascular accident and/or transient ischemic attack (odds ratio [OR], 3.06; 95% CI, 1.19-7.87], dementia (OR, 5.52; 95% CI, 2.19-13.93), and Parkinson disease (OR, 5; 95% CI, 1.57-15.94). A significantly higher percentage of cases had neurologic conditions (OR, 6.34; 95% CI, 2.89-13.91). Dementia and Parkinson disease were independently associated with bullous pemphigoid in the multivariate analysis. Patients with bullous pemphigoid have a higher frequency of neurologic conditions. Copyright © 2013 Elsevier España, S.L.U. and AEDV. All rights reserved.

Case-control vaccine effectiveness studies: Data collection, analysis and reporting results.

PubMed

Verani, Jennifer R; Baqui, Abdullah H; Broome, Claire V; Cherian, Thomas; Cohen, Cheryl; Farrar, Jennifer L; Feikin, Daniel R; Groome, Michelle J; Hajjeh, Rana A; Johnson, Hope L; Madhi, Shabir A; Mulholland, Kim; O'Brien, Katherine L; Parashar, Umesh D; Patel, Manish M; Rodrigues, Laura C; Santosham, Mathuram; Scott, J Anthony; Smith, Peter G; Sommerfelt, Halvor; Tate, Jacqueline E; Victor, J Chris; Whitney, Cynthia G; Zaidi, Anita K; Zell, Elizabeth R

2017-06-05

The case-control methodology is frequently used to evaluate vaccine effectiveness post-licensure. The results of such studies provide important insight into the level of protection afforded by vaccines in a 'real world' context, and are commonly used to guide vaccine policy decisions. However, the potential for bias and confounding are important limitations to this method, and the results of a poorly conducted or incorrectly interpreted case-control study can mislead policies. In 2012, a group of experts met to review recent experience with case-control studies evaluating vaccine effectiveness; we summarize the recommendations of that group regarding best practices for data collection, analysis, and presentation of the results of case-control vaccine effectiveness studies. Vaccination status is the primary exposure of interest, but can be challenging to assess accurately and with minimal bias. Investigators should understand factors associated with vaccination as well as the availability of documented vaccination status in the study context; case-control studies may not be a valid method for evaluating vaccine effectiveness in settings where many children lack a documented immunization history. To avoid bias, it is essential to use the same methods and effort gathering vaccination data from cases and controls. Variables that may confound the association between illness and vaccination are also important to capture as completely as possible, and where relevant, adjust for in the analysis according to the analytic plan. In presenting results from case-control vaccine effectiveness studies, investigators should describe enrollment among eligible cases and controls as well as the proportion with no documented vaccine history. Emphasis should be placed on confidence intervals, rather than point estimates, of vaccine effectiveness. Case-control studies are a useful approach for evaluating vaccine effectiveness; however careful attention must be paid to the collection

Case-control study on uveal melanoma (RIFA): rational and design

PubMed Central

Schmidt-Pokrzywniak, Andrea; Jöckel, Karl-Heinz; Bornfeld, Norbert; Stang, Andreas

2004-01-01

Background Although a rare disease, uveal melanoma is the most common primary intraocular malignancy in adults, with an incidence rate of up to 1.0 per 100,000 persons per year in Europe. Only a few consistent risk factors have been identified for this disease. We present the study design of an ongoing incident case-control study on uveal melanoma (acronym: RIFA study) that focuses on radiofrequency radiation as transmitted by radio sets and wireless telephones, occupational risk factors, phenotypical characteristics, and UV radiation. Methods/Design We conduct a case-control study to identify the role of different exposures in the development of uveal melanoma. The cases of uveal melanoma were identified at the Division of Ophthalmology, University of Essen, a referral centre for tumours of the eye. We recruit three control groups: population controls, controls sampled from those ophthalmologists who referred cases to the Division of Ophthalmology, University of Duisburg-Essen, and sibling controls. For each case the controls are matched on sex and age (five year groups), except for sibling controls. The data are collected from the study participants by short self-administered questionnaire and by telephone interview. During and at the end of the field phase, the data are quality-checked. To estimate the effect of exposures on uveal melanoma risk, we will use conditional logistic regression that accounts for the matching factors and allows to control for potential confounding. PMID:15318944

Sleep disturbances in fibromyalgia: A meta-analysis of case-control studies.

PubMed

Wu, Yu-Lin; Chang, Ling-Yin; Lee, Hsin-Chien; Fang, Su-Chen; Tsai, Pei-Shan

2017-05-01

Sleep disturbances are common in fibromyalgia, but the features of sleep disturbances are not well understood. We performed a systematic review and meta-analysis of case-control studies to compare the sleep outcomes of individuals with fibromyalgia and healthy controls. We systematically searched eight databases (PubMed, Ovid MEDLINE, Embase, CINAHL, PsycINFO, Web of Science, Airiti Library and Wanfang Data) for articles published before April 2016. Twenty-five case-controlled studies and a total of 2086 participants were included in the meta-analysis. Sleep was assessed using polysomnography and the Pittsburgh Sleep Quality Index. When sleep was assessed using polysomnography (19 studies), significant differences were observed in wake time after sleep onset (g=0.81, 95% confidence interval [CI] 0.21-1.41), total sleep time (g=-0.78, 95% CI=-1.34 to -0.15), sleep efficiency (g=-0.78, 95% CI=-1.23 to -0.32), percentage of stage 1 sleep (g=0.55, 95% CI=0.15-0.95), and percentage of slow-wave sleep (g=-0.66, 95% CI=-1.21 to -0.12) between participants with fibromyalgia and healthy controls. When sleep was assessed using the Pittsburgh Sleep Quality Index (7 studies), significant differences were observed in global scores (g=2.19, 95% CI 1.58-2.79), sleep onset latency (g=1.75, 95% CI 0.80-2.70), and sleep efficiency (g=-1.08, 95% CI -1.65 to -0.51) between participants with fibromyalgia and healthy controls. Individuals with fibromyalgia experience lower sleep quality and sleep efficiency; longer wake time after sleep onset, short sleep duration, and light sleep when objectively assessed and more difficulty in initiating sleep when subjectively assessed. Sleep difficulties in fibromyalgia appear to be more when reported subjectively than when assessed objectively. This study received no funding from any source. All authors declare that they have no conflict of interest. This article does not contain any studies with human participants performed by any of the authors

Differentiation of African components of ancestry to stratify groups in a case-control study of a Brazilian urban population.

PubMed

Silbiger, Vivian N; Hirata, Mario H; Luchessi, Andre D; Genvigir, Fabiana D V; Cerda, Alvaro; Rodrigues, Alice C; Willrich, Maria A V; Arazi, Simone S; Dorea, Egidio L; Bernik, Marcia M S; Faludi, Andre A; Bertolami, Marcelo C; Santos, Carla; Carracedo, Angel; Salas, Antonio; Freire, Ana; Lareu, Maria Victoria; Phillips, Christopher; Porras-Hurtado, Liliana; Fondevila, Manuel; Hirata, Rosario D C

2012-06-01

Balancing the subject composition of case and control groups to create homogenous ancestries between each group is essential for medical association studies. We explored the applicability of single-tube 34-plex ancestry informative markers (AIM) single nucleotide polymorphisms (SNPs) to estimate the African Component of Ancestry (ACA) to design a future case-control association study of a Brazilian urban sample. One hundred eighty individuals (107 case group; 73 control group) self-described as white, brown-intermediate or black were selected. The proportions of the relative contribution of a variable number of ancestral population components were similar between case and control groups. Moreover, the case and control groups demonstrated similar distributions for ACA <0.25 and >0.50 categories. Notably a high number of outlier values (23 samples) were observed among individuals with ACA <0.25. These individuals presented a high probability of Native American and East Asian ancestral components; however, no individuals originally giving these self-described ancestries were observed in this study. The strategy proposed for the assessment of ancestry and adjustment of case and control groups for an association study is an important step for the proper construction of the study, particularly when subjects are taken from a complex urban population. This can be achieved using a straight forward multiplexed AIM-SNPs assay of highly discriminatory ancestry markers.

Adjusting for geographic variation in observational comparative effectiveness studies: a case study of antipsychotics using state Medicaid data.

PubMed

Root, Elisabeth Dowling; Thomas, Deborah S K; Campagna, Elizabeth J; Morrato, Elaine H

2014-08-27

Area-level variation in treatment and outcomes may be a potential source of confounding bias in observational comparative effectiveness studies. This paper demonstrates how to use exploratory spatial data analysis (ESDA) and spatial statistical methods to investigate and control for these potential biases. The case presented compares the effectiveness of two antipsychotic treatment strategies: oral second-generation antipsychotics (SGAs) vs. long-acting paliperiodone palmitate (PP). A new-start cohort study was conducted analyzing patient-level administrative claims data (8/1/2008-4/30/2011) from Missouri Medicaid. ESDA techniques were used to examine spatial patterns of antipsychotic prescriptions and outcomes (hospitalization and emergency department (ED) visits). Likelihood of mental health-related outcomes were compared between patients starting PP (N = 295) and oral SGAs (N = 8,626) using multilevel logistic regression models adjusting for patient composition (demographic and clinical factors) and geographic region. ESDA indicated significant spatial variation in antipsychotic prescription patterns and moderate variation in hospitalization and ED visits thereby indicating possible confounding by geography. In the multilevel models for this antipsychotic case example, patient composition represented a stronger source of confounding than geographic context. Because geographic variation in health care delivery is ubiquitous, it could be a comparative effectiveness research (CER) best practice to test for possible geographic confounding in observational data. Though the magnitude of the area-level geography effects were small in this case, they were still statistically significant and should therefore be examined as part of this observational CER study. More research is needed to better estimate the range of confounding due to geography across different types of observational comparative effectiveness studies and healthcare utilization outcomes.

Childhood brain tumours and use of mobile phones: comparison of a case-control study with incidence data.

PubMed

Aydin, Denis; Feychting, Maria; Schüz, Joachim; Röösli, Martin

2012-05-20

The first case-control study on mobile phone use and brain tumour risk among children and adolescents (CEFALO study) has recently been published. In a commentary published in Environmental Health, Söderqvist and colleagues argued that CEFALO suggests an increased brain tumour risk in relation to wireless phone use. In this article, we respond and show why consistency checks of case-control study results with observed time trends of incidence rates are essential, given the well described limitations of case-control studies and the steep increase of mobile phone use among children and adolescents during the last decade. There is no plausible explanation of how a notably increased risk from use of wireless phones would correspond to the relatively stable incidence time trends for brain tumours among children and adolescents observed in the Nordic countries. Nevertheless, an increased risk restricted to heavy mobile phone use, to very early life exposure, or to rare subtypes of brain tumours may be compatible with stable incidence trends at this time and thus further monitoring of childhood brain tumour incidence rate time trends is warranted.

Control selection and confounding factors: A lesson from a Japanese case-control study to examine acellular pertussis vaccine effectiveness.

PubMed

Ohfuji, Satoko; Okada, Kenji; Nakano, Takashi; Ito, Hiroaki; Hara, Megumi; Kuroki, Haruo; Hirota, Yoshio

2017-08-24

When using a case-control study design to examine vaccine effectiveness, both the selection of control subjects and the consideration of potential confounders must be the important issues to ensure accurate results. In this report, we described our experience from a case-control study conducted to evaluate the effectiveness of acellular pertussis vaccine combined with diphtheria-tetanus toxoids (DTaP vaccine). Newly diagnosed pertussis cases and age- and sex-matched friend-controls were enrolled, and the history of DTaP vaccination was compared between groups. Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) of vaccination for development of pertussis. After adjustment for potential confounders, four doses of DTaP vaccination showed a lower OR for pediatrician-diagnosed pertussis (OR=0.11, 95% CI, 0.01-0.99). In addition, the decreasing OR of four doses vaccination was more pronounced for laboratory-confirmed pertussis (OR=0.07, 95%CI, 0.01-0.82). Besides, positive association with pertussis was observed in subjects with a history of steroid treatment (OR=5.67) and those with a recent contact with a lasting cough (OR=4.12). When using a case-control study to evaluate the effectiveness of vaccines, particularly those for uncommon infectious diseases such as pertussis, the use of friend-controls may be optimal due to the fact that they shared a similar experience for exposure to the pathogen as the cases. In addition, to assess vaccine effectiveness as accurately as possible, the effects of confounding should be adequately controlled with a matching or analysis technique. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

[False positive result in mammography and its association with the presence of obesity: a case-control study].

PubMed

Castro-Ibarra, Marisela; Menchaca-Díaz, Rufino; Cabrales-Ruvalcaba, J Jesús; Luna-V Gómez, Rosa Alicia

2016-01-01

To analyze the association between a false positive result in mammography and obesity, inside the breast cancer early detection program in women affiliated to the Institute of Security and Social Services for Government and Municipality workers of the State of Baja California (ISSSTECALI). A case-control, retrospective study was done in women affiliated to ISSSTECALI to whom a mammography was performed between 2009 and 2012. Women with a false positive result in mammography were included as cases. Controls were women with a true negative result in mammography. Three controls were randomly selected for each case. Obesity was established with the body mass index (BMI) consigned in the woman's clinical file. Age and estrogen replacement therapy were included as co-variables. Seventy nine cases were identified and 237 controls were included. Obesity was observed in 54.4% of cases and in 41.3% of controls (odds ratio: 1.69; 95% confidence interval for odds ratio: 1.01-2.82; p value: 0.043). A logistic regression model including covariables maintained the observed association (p = 0.044). No association was found with analyzed co-variables. A false positive result in mammography was associated with the presence of obesity.

Bias reduction in repeated-measures observational studies by the use of propensity score: the case of enteral sedation for critically ill patients.

PubMed

Umbrello, Michele; Mistraletti, Giovanni; Corbella, Davide; Cigada, Marco; Salini, Silvia; Morabito, Alberto; Iapichino, Gaetano

2012-12-01

Within the evidence-based medicine paradigm, randomized controlled trials represent the "gold standard" to produce reliable evidence. Indeed, planning and implementing randomized controlled trials in critical care medicine presents limitations because of intrinsic and structural problems. As a consequence, observational studies still occur frequently. In these cases, propensity score (PS) (probability of receiving a treatment conditional on observed covariates) is an increasingly used technique to adjust the results. Few studies addressed the specific issue of a PS correction of repeated-measures designs. Three techniques for correcting the analysis of nonrandomized designs (matching, stratification, regression adjustment) are presented in a tutorial form and applied to a real case study: the comparison between intravenous and enteral sedative therapy in the intensive care unit setting. After showing the results before and after the use of PS, we suggest that such a tool allows to partially overcoming the bias associated with the observational nature of the study. It permits to correct the estimates for any observed covariate, while unobserved confounders cannot be controlled for. Propensity score represents a useful additional tool to estimate the effects of treatments in nonrandomized studies. In the case study, an enteral sedation approach was equally effective to an intravenous regime, allowing for a lower level of sedation and spare of resources. Copyright © 2012 Elsevier Inc. All rights reserved.

Fruit and vegetable consumption and lung cancer risk: a case-control study in Galicia, Spain.

PubMed

Tarrazo-Antelo, Ana Marina; Ruano-Ravina, Alberto; Abal Arca, José; Barros-Dios, Juan Miguel

2014-01-01

Lung cancer has multiple risk factors and tobacco is the main one. Diet plays a role, but no clear effect has been consistently observed for different fruit and vegetable consumption. We aim to assess the association between fruit and vegetable consumption and lung cancer risk through a hospital-based case-control study in Spanish population. We recruited incident lung cancer cases in 2 Spanish hospitals from 2004 to 2008. Controls were individuals attending hospital for trivial surgery. Cases and controls were older than 30 and did not have a neoplasic history. We collected information on lifestyle with special emphases on tobacco and dietary habits. We included 371 cases and 496 controls. We found no protective effect for overall fruit consumption. For green leafy vegetables, the odds ratio (OR) was 0.92 [95% confidence interval (CI) = 0.32-2.69), and for other vegetables the OR was 0.77 (95% CI = 0.40-1.48) for the categories compared. We observed a reduced risk for broccoli and pumpkin intake. Although fruit consumption does not seem to be associated with a lower lung cancer risk, only the frequent consumption of specific green leafy vegetables and other vegetables might be associated with a reduced risk of lung cancer.

Case-control study: soft-tissue sarcomas and exposure to phenoxyacetic acids or chlorophenols.

PubMed Central

Hardell, L.; Sandström, A.

1979-01-01

In 1977 a number of patients with soft-tissue sarcomas and previous exposure to phenoxyacetic acids were described. Following from these observations a matched case-control study was made. Exposure to chlorophenols was also included in this study. The results showed that exposure to phenoxyacetic acids or chlorophenols gave an approximately 6-fold increase in the risk for this type of tumour. It was not possible to determine, however, whether the carcinogenic effect was exerted by these compounds or by impurities such as chlorinated dibenzodioxins and dibenzofurans that in almost all cases were part of the commercial preparations. PMID:444410

The Misconception of Case-Control Studies in the Plastic Surgery Literature: A Literature Audit.

PubMed

Hatchell, Alexandra C; Farrokhyar, Forough; Choi, Matthew

2017-06-01

Case-control study designs are commonly used. However, many published case-control studies are not true case-controls and are in fact mislabeled. The purpose of this study was to identify all case-control studies published in the top three plastic surgery journals over the past 10 years, assess which were truly case-control studies, clarify the actual design of the articles, and address common misconceptions. MEDLINE, Embase, and Web of Science databases were searched for case-control studies in the three highest-impact factor plastic surgery journals (2005 to 2015). Two independent reviewers screened the resulting titles, abstracts, and methods, if applicable, to identify articles labeled as case-control studies. These articles were appraised and classified as true case-control studies or non-case-control studies. The authors found 28 articles labeled as case-control studies. However, only six of these articles (21 percent) were truly case-control designs. Of the 22 incorrectly labeled studies, one (5 percent) was a randomized controlled trial, three (14 percent) were nonrandomized trials, two (9 percent) were prospective comparative cohort designs, 14 (64 percent) were retrospective comparative cohort designs, and two (9 percent) were cross-sectional designs. The mislabeling was worse in recent years, despite increases in evidence-based medicine awareness. The majority of published case-control studies are not in fact case-control studies. This misunderstanding is worsening with time. Most of these studies are actually comparative cohort designs. However, some studies are truly clinical trials and thus a higher level of evidence than originally proposed.

Welding and Lung Cancer in a Pooled Analysis of Case-Control Studies

PubMed Central

Kendzia, Benjamin; Behrens, Thomas; Jöckel, Karl-Heinz; Siemiatycki, Jack; Kromhout, Hans; Vermeulen, Roel; Peters, Susan; Van Gelder, Rainer; Olsson, Ann; Brüske, Irene; Wichmann, H.-Erich; Stücker, Isabelle; Guida, Florence; Tardón, Adonina; Merletti, Franco; Mirabelli, Dario; Richiardi, Lorenzo; Pohlabeln, Hermann; Ahrens, Wolfgang; Landi, Maria Teresa; Caporaso, Neil; Consonni, Dario; Zaridze, David; Szeszenia-Dabrowska, Neonila; Lissowska, Jolanta; Gustavsson, Per; Marcus, Michael; Fabianova, Eleonora; ‘t Mannetje, Andrea; Pearce, Neil; Tse, Lap Ah; Yu, Ignatius Tak-sun; Rudnai, Peter; Bencko, Vladimir; Janout, Vladimir; Mates, Dana; Foretova, Lenka; Forastiere, Francesco; McLaughlin, John; Demers, Paul; Bueno-de-Mesquita, Bas; Boffetta, Paolo; Schüz, Joachim; Straif, Kurt; Pesch, Beate; Brüning, Thomas

2013-01-01

Several epidemiologic studies have indicated an increased risk of lung cancer among welders. We used the SYNERGY project database to assess welding as a risk factor for developing lung cancer. The database includes data on 15,483 male lung cancer cases and 18,388 male controls from 16 studies in Europe, Canada, China, and New Zealand conducted between 1985 and 2010. Odds ratios and 95% confidence intervals between regular or occasional welding and lung cancer were estimated, with adjustment for smoking, age, study center, and employment in other occupations associated with lung cancer risk. Overall, 568 cases and 427 controls had ever worked as welders and had an odds ratio of developing lung cancer of 1.44 (95% confidence interval: 1.25, 1.67) with the odds ratio increasing for longer duration of welding. In never and light smokers, the odds ratio was 1.96 (95% confidence interval: 1.37, 2.79). The odds ratios were somewhat higher for squamous and small cell lung cancers than for adenocarcinoma. Another 1,994 cases and 1,930 controls had ever worked in occupations with occasional welding. Work in any of these occupations was associated with some elevation of risk, though not as much as observed in regular welders. Our findings lend further support to the hypothesis that welding is associated with an increased risk of lung cancer. PMID:24052544

Welding and lung cancer in a pooled analysis of case-control studies.

PubMed

Kendzia, Benjamin; Behrens, Thomas; Jöckel, Karl-Heinz; Siemiatycki, Jack; Kromhout, Hans; Vermeulen, Roel; Peters, Susan; Van Gelder, Rainer; Olsson, Ann; Brüske, Irene; Wichmann, H-Erich; Stücker, Isabelle; Guida, Florence; Tardón, Adonina; Merletti, Franco; Mirabelli, Dario; Richiardi, Lorenzo; Pohlabeln, Hermann; Ahrens, Wolfgang; Landi, Maria Teresa; Caporaso, Neil; Consonni, Dario; Zaridze, David; Szeszenia-Dabrowska, Neonila; Lissowska, Jolanta; Gustavsson, Per; Marcus, Michael; Fabianova, Eleonora; 't Mannetje, Andrea; Pearce, Neil; Tse, Lap Ah; Yu, Ignatius Tak-Sun; Rudnai, Peter; Bencko, Vladimir; Janout, Vladimir; Mates, Dana; Foretova, Lenka; Forastiere, Francesco; McLaughlin, John; Demers, Paul; Bueno-de-Mesquita, Bas; Boffetta, Paolo; Schüz, Joachim; Straif, Kurt; Pesch, Beate; Brüning, Thomas

2013-11-15

Several epidemiologic studies have indicated an increased risk of lung cancer among welders. We used the SYNERGY project database to assess welding as a risk factor for developing lung cancer. The database includes data on 15,483 male lung cancer cases and 18,388 male controls from 16 studies in Europe, Canada, China, and New Zealand conducted between 1985 and 2010. Odds ratios and 95% confidence intervals between regular or occasional welding and lung cancer were estimated, with adjustment for smoking, age, study center, and employment in other occupations associated with lung cancer risk. Overall, 568 cases and 427 controls had ever worked as welders and had an odds ratio of developing lung cancer of 1.44 (95% confidence interval: 1.25, 1.67) with the odds ratio increasing for longer duration of welding. In never and light smokers, the odds ratio was 1.96 (95% confidence interval: 1.37, 2.79). The odds ratios were somewhat higher for squamous and small cell lung cancers than for adenocarcinoma. Another 1,994 cases and 1,930 controls had ever worked in occupations with occasional welding. Work in any of these occupations was associated with some elevation of risk, though not as much as observed in regular welders. Our findings lend further support to the hypothesis that welding is associated with an increased risk of lung cancer.

Occupation and keratinocyte cancer risk: a population-based case-control study.

PubMed

Marehbian, Josh; Colt, Joanne S; Baris, Dalsu; Stewart, Patricia; Stukel, Therese A; Spencer, Steven K; Karagas, Margaret R

2007-10-01

The aim of our study was to identify occupations associated with increased risk of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). We conducted a population-based case-control study of BCC and SCC in New Hampshire. Cases (n = 599 BCC, n = 290 SCC) and controls (n = 524) completed a self-administered residence and work history questionnaire and personal interview regarding major risk factors for skin cancer. Reported jobs were coded using the Standardized Occupational Classification system (SOC). Odds ratios (ORs) and confidence intervals (CIs) for BCC and SCC were calculated for men and women separately using unconditional logistic regression models taking into account age, education, skin reaction to sun, history of painful sunburns, time spent outdoors, and for SCC, smoking. Among men, we observed elevated risks of both BCC and SCC among groundskeepers and gardeners, except farm (SOC 5622). We also found that garage and service station-related occupations (SOCs 873) and to some extent food/beverage preparation/service occupations (SOC 521) were associated with BCC risk among men. Women in health services occupations (SOC 523) had elevated risks for both tumors, especially for BCC. Additionally, administrative support (SOC 46/47) occupations were related to BCC risk among women. Other occupations were associated with excess risks, but without consistent trends by duration of employment. We observed several occupations associated with elevated BCC and SCC risk. These results resemble reported findings for cutaneous melanoma and are generally consistent with the few available studies on keratinocyte cancers.

Esophageal cancer among Brazilian agricultural workers: case-control study based on death certificates.

PubMed

Meyer, Armando; Alexandre, Pedro Celso Braga; Chrisman, Juliana de Rezende; Markowitz, Steven B; Koifman, Rosalina Jorge; Koifman, Sergio

2011-03-01

Several studies suggest that agricultural workers are at higher risk to develop and die by certain types of cancer. Esophageal cancer is not commonly listed among these types. However, some recent studies indicated that if there is an association between agricultural working and esophageal cancer, it s more likely to be observed among workers highly exposed to pesticides. In the present study, the magnitude of the association between agricultural working and esophageal cancer mortality was evaluated in a high pesticide use area in Brazil, through a death certificate-based case-control study. Cases were individuals from both genders, 30-59 years old, for whom basic cause of death was ascertained as cancer of the esophagus. For each case, one control was randomly selected from all possible controls for which the basic cause of death was ascertained as different from neoplasm and diseases of the digestive system. In addition, controls matched their cases by sex, age, year of death, and state of residence. Crude and adjusted odds ratios were then calculated to estimate the magnitude of the risk. Results showed that, in general, agricultural workers were at significantly higher risk to die by esophageal cancer, when compared to non-agricultural workers. Stratified analysis also revealed that the magnitude of such risk was slightly higher among illiterate agricultural workers, and simultaneous adjustment for several covariates showed that the risk was quantitatively higher among younger southern agricultural workers. These results suggest the esophageal cancer may be included among those types of cancer etiologically associated to agricultural working. Copyright © 2010 Elsevier GmbH. All rights reserved.

Vitamin D and Fracture Risk in Early Childhood: A Case-Control Study

PubMed Central

Anderson, Laura N.; Heong, Sze Wing; Chen, Yang; Thorpe, Kevin E.; Adeli, Khosrow; Howard, Andrew; Sochett, Etienne; Birken, Catherine S.; Parkin, Patricia C.; Maguire, Jonathon L.; Abdullah, Kawsari; Anderson, Laura N.; Birken, Catherine S.; Borkhoff, Cornelia M.; Carsley, Sarah; Chen, Yang; Katz-Lavigne, Mikael; Kavikondala, Kanthi; Kowal, Christine; Maguire, Jonathon L.; Mason, Dalah; Omand, Jessica; Parkin, Patricia C.; Persaud, Navindra; van den Heuvel, Meta; Baker, Jillian; Barozzino, Tony; Bonifacio, Joey; Campbell, Douglas; Cheema, Sohail; Chisamore, Brian; Danayan, Karoon; Das, Paul; Derocher, Mary Beth; Do, Anh; Dorey, Michael; Freeman, Sloane; Fung, Keewai; Guiang, Charlie; Handford, Curtis; Hatch, Hailey; Jacobson, Sheila; Kiran, Tara; Knowles, Holly; Kwok, Bruce; Lakhoo, Sheila; Lam-Antoniades, Margarita; Lau, Eddy; Leung, Fok-Han; Loo, Jennifer; Mahmoud, Sarah; Moodie, Rosemary; Morinis, Julia; Naymark, Sharon; Neelands, Patricia; Owen, James; Peer, Michael; Perlmutar, Marty; Persaud, Navindra; Pinto, Andrew; Porepa, Michelle; Ramji, Nasreen; Ramji, Noor; Rosenthal, Alana; Saunderson, Janet; Saxena, Rahul; Sgro, Michael; Shepherd, Susan; Smiltnieks, Barbara; Taylor, Carolyn; Weisdors, Thea; Wijayasinghe, Sheila; Wong, Peter; Ying, Ethel; Young, Elizabeth

2017-01-01

Abstract The objective of this study was to evaluate the association of vitamin D intake and serum levels with fracture risk in children under 6 years of age. A case-control study was conducted in Toronto, Ontario, Canada. Cases were recruited from the fracture clinic at the Hospital for Sick Children, and matched controls were obtained from the TARGet Kids! primary-care research network. Controls were matched to cases on age, sex, height, and season. Fracture risk was estimated from conditional logistic regression, with adjustment for skin type, fracture history, waist circumference, outdoor free play, neighborhood income, soda consumption, and child's birth weight. A total of 206 cases were recruited during May 2009–April 2013 and matched to 343 controls. Serum 25-hydroxyvitamin D concentration (per 10-nmol/L increment: adjusted odds ratio (aOR) = 0.95, 95% confidence interval (CI): 0.88, 1.03) and intake of cow's milk (<2 cups/day vs. 2 cups/day: aOR = 0.95 (95% CI: 0.60, 1.52); >2 cups/day vs. 2 cups/day: aOR = 1.39 (95% CI: 0.85, 2.23)) were not significantly associated with reduced odds of fracture. A statistically significant association was observed between child use of vitamin D supplements and decreased odds of fracture (yes vs. no: aOR = 0.42, 95% CI: 0.25, 0.69). Vitamin D supplementation, but not serum 25-hydroxyvitamin D level or milk intake, was associated with reduced fracture risk among these healthy young children. PMID:28459987

Is case-chaos methodology an appropriate alternative to conventional case-control studies for investigating outbreaks?

PubMed

Edelstein, Michael; Wallensten, Anders; Kühlmann-Berenzon, Sharon

2014-08-15

Case-chaos methodology is a proposed alternative to case-control studies that simulates controls by randomly reshuffling the exposures of cases. We evaluated the method using data on outbreaks in Sweden. We identified 5 case-control studies from foodborne illness outbreaks that occurred between 2005 and 2012. Using case-chaos methodology, we calculated odds ratios 1,000 times for each exposure. We used the median as the point estimate and the 2.5th and 97.5th percentiles as the confidence interval. We compared case-chaos matched odds ratios with their respective case-control odds ratios in terms of statistical significance. Using Spearman's correlation, we estimated the correlation between matched odds ratios and the proportion of cases exposed to each exposure and quantified the relationship between the 2 using a normal linear mixed model. Each case-control study identified an outbreak vehicle (odds ratios = 4.9-45). Case-chaos methodology identified the outbreak vehicle 3 out of 5 times. It identified significant associations in 22 of 113 exposures that were not associated with outcome and 5 of 18 exposures that were significantly associated with outcome. Log matched odds ratios correlated with their respective proportion of cases exposed (Spearman ρ = 0.91) and increased significantly with the proportion of cases exposed (b = 0.054). Case-chaos methodology missed the outbreak source 2 of 5 times and identified spurious associations between a number of exposures and outcome. Measures of association correlated with the proportion of cases exposed. We recommended against using case-chaos analysis during outbreak investigations. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A case-control study of mesothelioma in Minnesota iron ore (taconite) miners.

PubMed

Lambert, Christine S; Alexander, Bruce H; Ramachandran, Gurumurthy; MacLehose, Richard F; Nelson, Heather H; Ryan, Andrew D; Mandel, Jeffrey H

2016-02-01

An excess of mesothelioma has been observed in iron ore miners in Northeastern Minnesota. Mining and processing of taconite iron ore generate exposures that include elongate mineral particles (EMPs) of amphibole and non-amphibole origin. We conducted a nested case-control study of mesothelioma in a cohort of 68,737 iron ore miners (haematite and taconite ore miners) to evaluate the association between mesothelioma, employment and EMP exposures from taconite mining. Mesothelioma cases (N=80) were identified through the Minnesota Cancer Surveillance System (MCSS) and death certificates. Four controls of similar age were selected for each case with 315 controls ultimately eligible for inclusion. Mesothelioma risk was evaluated by estimating rate ratios and 95% CIs with conditional logistic regression in relation to duration of taconite industry employment and cumulative EMP exposure [(EMP/cc)×years], defined by the National Institute for Occupational Safety and Health (NIOSH) 7400 method. Models were adjusted for employment in haematite mining and potential exposure to commercial asbestos products used in the industry. All mesothelioma cases were male and 57 of the cases had work experience in the taconite industry. Mesothelioma was associated with the number of years employed in the taconite industry (RR=1.03, 95% CI 1.00 to 1.06) and cumulative EMP exposure (RR=1.10, 95% CI 0.97 to -1.24). No association was observed with employment in haematite mining. These results support an association between mesothelioma and employment duration and possibly EMP exposure in taconite mining and processing. The type of EMP was not determined. The potential role of commercial asbestos cannot be entirely ruled out. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Intrahousehold resource allocation and child growth in Mozambique: an ethnographic case-control study.

PubMed

Pfeiffer, J; Gloyd, S; Ramirez Li, L

2001-07-01

This study examines the effect of intrahousehold cash income control and decision-making patterns on child growth in the rural town of Sussundenga in Manica Province, Mozambique. A case-control study design was used to examine the influence of men's and women's disaggregated cash incomes on child growth. The research tested whether greater maternal share of household cash income was associated with (1) increased maternal decision-making and bargaining power in the household, and (2) better child growth. Fifty case households, with children 1-4 years old exhibiting poor growth, were matched with 50 control households of similar socioeconomic status in which all children under five demonstrated healthy growth. Data were gathered on gender-specific income generation and expenditure, specific intrahousehold allocation processes, diet, and sociodemographic variables using a formal survey. Key informant interviews, focus groups, and observation over one year provided ethnographic context for the case-control findings. Case-control differences were analyzed using McNemar's test, paired t-test, and conditional logistic regression. In spite of matching households for socioeconomic status, control household incomes were still slightly greater than cases. Male spouse income was also higher among controls while maternal income, and maternal proportion of household income, were not significantly different. Household meat, fish and poultry consumption, and maternal education were significantly greater among control households than cases. Greater maternal share of household income was not associated with greater maternal decision-making around cash. However, mothers must spend what little cash they earn on daily food supplies and usually request additional cash from spouses to cover these costs. There is evidence that if mothers earn enough to cover these socially prescribed costs, they can spend cash for other needs. Above this threshold, women's earnings may confer more

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

Melasma and its association with different types of nevi in women: A case-control study

PubMed Central

Adalatkhah, Hassan; Sadeghi-bazargani, Homayoun; Amini-sani, Nayereh; Zeynizadeh, Somayeh

2008-01-01

Background Very little is known about possible association of nevi and melasma. The study objective was to determine if there is an association between melasma and existence of different kinds of nevi. Methods In a case-control study, 120 female melasma patients referred to dermatology clinic of Ardabil and 120 patients referred to other specialty clinics who lacked melasma were enrolled after matching for age. Number of different types of nevi including lentigines and melanocytic nevi were compared between case and control group patients. Data were entered into the computer and analyzed by SPSS 13 statistical software. Results Mean number of lentigines was 25.5 in melasma group compared to 8 in control group(P < 0.01). Mean number of melanocytic nevi was 13.2 in cases compared to 2.8 in control group(P < 0.001). Multivariate analysis showed that existence of freckles, lentigines and more than three melanocytic nevi were positively related to developing melasma. The chance of melasma increased up to 23 times for patients having more than three melanocytic nevi. Congenital nevi were observed among 10% both in case and control groups. Campbell de morgan angiomas were seen among 26 patients(21.8%) in case group compared to 6 patients(5%) in control group. Conclusion Existence of lentigines and melanocytic nevi increases chance of having melasma PMID:18680608

Impact of waning acquired immunity and asymptomatic infections on case-control studies for enteric pathogens.

PubMed

Havelaar, Arie H; Swart, Arno

2016-12-01

Case-control studies of outbreaks and of sporadic cases of infectious diseases may provide a biased estimate of the infection rate ratio, due to selecting controls that are not at risk of disease. We use a dynamic mathematical model to explore biases introduced in results drawn from case-control studies of enteric pathogens by waning and boosting of immunity, and by asymptomatic infections, using Campylobacter jejuni as an example. Individuals in the population are either susceptible (at risk of infection and disease), fully protected (not at risk of either) or partially protected (at risk of infection but not of disease). The force of infection is a function of the exposure frequency and the exposure dose. We show that the observed disease odds ratios are indeed strongly biased towards the null, i.e. much lower than the infection rate ratio, and furthermore even not proportional to it. The bias could theoretically be controlled by sampling controls only from the reservoir of susceptible individuals. The population at risk is in a dynamic equilibrium, and cannot be identified as those who are not and have never experienced disease. Individual-level samples to measure protective immunity would be required, complicating the design, cost and execution of case-control studies. Copyright © 2016 The Author(s). Published by Elsevier B.V. All rights reserved.

Antiviral immunity following smallpox virus infection: a case-control study.

PubMed

Hammarlund, Erika; Lewis, Matthew W; Hanifin, Jon M; Mori, Motomi; Koudelka, Caroline W; Slifka, Mark K

2010-12-01

Outbreaks of smallpox (i.e., caused by variola virus) resulted in up to 30% mortality, but those who survived smallpox infection were regarded as immune for life. Early studies described the levels of neutralizing antibodies induced after infection, but smallpox was eradicated before contemporary methods for quantifying T-cell memory were developed. To better understand the levels and duration of immunity after smallpox infection, we performed a case-control study comparing antiviral CD4(+) and CD8(+) T-cell responses and neutralizing antibody levels of 24 smallpox survivors with the antiviral immunity observed in 60 smallpox-vaccinated (i.e., vaccinia virus-immune) control subjects. We found that the duration of immunity following smallpox infection was remarkably similar to that observed after smallpox vaccination, with antiviral T-cell responses that declined slowly over time and antiviral antibody responses that remained stable for decades after recovery from infection. These results indicate that severe, potentially life-threatening disease is not required for the development of sustainable long-term immunity. This study shows that the levels of immunity induced following smallpox vaccination are comparable in magnitude to that achieved through natural variola virus infection, and this may explain the notable success of vaccination in eradicating smallpox, one of the world's most lethal diseases.

Controls Astrophysics and Structures Experiment in Space (CASES) advanced studies and planning

NASA Technical Reports Server (NTRS)

Wu, S. T.

1989-01-01

The CASES (Controls, Astrophysics, and Structures Experiment in Space) program consists of a flight demonstration of CSI (Controls-Structures Interactions) technology on the Space Shuttle. The basis structure consists of a 32 m deployable boom with actuators and sensors distributed along its length. Upon deployment from the Orbiter bay, the CASES structure will be characterized dynamically and its deformations controlled by a series of experimental control laws; and cold gas thrusters at its tip will be used to orient the Orbiter to a fixed celestial reference. The scientific observations will consist of hard x-ray imaging, at high resolution, of the Sun and the Galactic center. The hard x-ray observations require stable (few arc min) pointing at these targets for one or more position-sensitive proportional counters in the Orbiter bay, which view the object to be imaged through an aperture-encoding mask at the boom tip. This report gives the concensus developed at the second CASES Science Working Group meeting, which took place at NASA Marshall Space Flight Center May 16-17, 1990. An earlier paper and scientific summaries are available and form the basis for the present discussion.

Correcting for batch effects in case-control microbiome studies

PubMed Central

Gibbons, Sean M.; Duvallet, Claire

2018-01-01

High-throughput data generation platforms, like mass-spectrometry, microarrays, and second-generation sequencing are susceptible to batch effects due to run-to-run variation in reagents, equipment, protocols, or personnel. Currently, batch correction methods are not commonly applied to microbiome sequencing datasets. In this paper, we compare different batch-correction methods applied to microbiome case-control studies. We introduce a model-free normalization procedure where features (i.e. bacterial taxa) in case samples are converted to percentiles of the equivalent features in control samples within a study prior to pooling data across studies. We look at how this percentile-normalization method compares to traditional meta-analysis methods for combining independent p-values and to limma and ComBat, widely used batch-correction models developed for RNA microarray data. Overall, we show that percentile-normalization is a simple, non-parametric approach for correcting batch effects and improving sensitivity in case-control meta-analyses. PMID:29684016

Brain cancer and nonoccupational risk factors: a case-control study among workers at two nuclear facilities

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

Carpenter, A.V.; Flanders, W.D.; Frome, E.L.

1987-09-01

In a nested case-control study of nuclear workers, 82 brain cancer cases were compared with 328 matched controls to investigate the possible association with nonoccupational risk factors such as histories of epilepsy or head injury. We observed a moderately strong association between brain cancer occurrence and history of epilepsy (OR = 5.7, 95 per cent CI: 1.0, 32.1), but did not find a positive association with previous head injury (OR = 0.9, 95 per cent CI: 0.2, 4.2).

Multiple imputation of missing data in nested case-control and case-cohort studies.

PubMed

Keogh, Ruth H; Seaman, Shaun R; Bartlett, Jonathan W; Wood, Angela M

2018-06-05

The nested case-control and case-cohort designs are two main approaches for carrying out a substudy within a prospective cohort. This article adapts multiple imputation (MI) methods for handling missing covariates in full-cohort studies for nested case-control and case-cohort studies. We consider data missing by design and data missing by chance. MI analyses that make use of full-cohort data and MI analyses based on substudy data only are described, alongside an intermediate approach in which the imputation uses full-cohort data but the analysis uses only the substudy. We describe adaptations to two imputation methods: the approximate method (MI-approx) of White and Royston () and the "substantive model compatible" (MI-SMC) method of Bartlett et al. (). We also apply the "MI matched set" approach of Seaman and Keogh () to nested case-control studies, which does not require any full-cohort information. The methods are investigated using simulation studies and all perform well when their assumptions hold. Substantial gains in efficiency can be made by imputing data missing by design using the full-cohort approach or by imputing data missing by chance in analyses using the substudy only. The intermediate approach brings greater gains in efficiency relative to the substudy approach and is more robust to imputation model misspecification than the full-cohort approach. The methods are illustrated using the ARIC Study cohort. Supplementary Materials provide R and Stata code. © 2018, The International Biometric Society.

Clinical Signs and Blood Test Results Among Humans Infected With Zoonotic Simian Foamy Virus: A Case-Control Study.

PubMed

Buseyne, Florence; Betsem, Edouard; Montange, Thomas; Njouom, Richard; Bilounga Ndongo, Chanceline; Hermine, Olivier; Gessain, Antoine

2018-06-05

A spillover of simian foamy virus (SFV) to humans, following bites from infected nonhuman primates (NHPs), is ongoing in exposed populations. These retroviruses establish persistent infections of unknown physiological consequences to the human host. We performed a case-control study to compare 24 Cameroonian hunters infected with gorilla SFV and 24 controls matched for age and ethnicity. A complete physical examination and blood test were performed for all participants. Logistic regression and Wilcoxon signed rank tests were used to compare cases and controls. The cases had significantly lower levels of hemoglobin than the controls (median, 12.7 vs 14.4 g/dL; P = .01). Basophil levels were also significantly lower in cases than controls, with no differences for other leukocyte subsets. Cases had significantly higher urea, creatinine, protein, creatinine phosphokinase, and lactate dehydrogenase levels and lower bilirubin levels than controls. Cases and controls had similar frequencies of general, cutaneous, gastrointestinal, neurological, and cardiorespiratory signs. The first case-control study of apparently healthy SFV-infected Cameroonian hunters showed the presence of hematological abnormalities. A thorough clinical and laboratory workup is now needed to establish the medical relevance of these observations because more than half of cases had mild or moderate anemia. NCT03225794.

Cutaneous reactions to proton pump inhibitors: a case-control study.

PubMed

Chularojanamontri, Leena; Jiamton, Sukhum; Manapajon, Araya; Suvanasuthi, Saroj; Kulthanan, Kanokvalai; Dhana, Naruemon; Jongjarearnprasert, Kowit

2012-10-01

Even though proton pump inhibitors (PPIs) are commonly used in clinical practice, a limited number of studies are available about cutaneous adverse reactions from PPIs, and most of these are case reports. To demonstrate the pattern of cutaneous reactions related to PPI usage and to evaluate the risk of developing PPI drug eruptions among adult patients. We reviewed the spontaneous reports of any adverse events associated with PPI use, as reported from January 2005 through May 2010 to the Adverse Drug Reaction Center at Siriraj Hospital in Thailand. Each control was sampled from 15 patients who had consecutive hospital numbers from each study case. The prevalence of cutaneous reactions to PPIs varied, ranging from three to 20 per 100,000 of the treated population. Sixty-four patients with a history of reaction to PPIs, and 65 controls were enrolled. Most cutaneous reactions were attributed to omeprazole (n=50; 78.1%), and the most frequently observed cutaneous reaction was maculopapular rash (43.8%). None of the patients experienced a cross-reaction between individual PPIs. Cutaneous adverse reactions to PPIs range from minor drug rashes to a severe, life-threatening reaction. Individuals with a history of adverse drug reaction have an increased risk of cutaneous reaction to PPIs.

A cholera outbreak in Alborz Province, Iran: a matched case-control study.

PubMed

Moradi, Ghobad; Rasouli, Mohammad Aziz; Mohammadi, Parvin; Elahi, Elham; Barati, Hojatollah

2016-01-01

A total of 229 confirmed cholera cases were reported in Alborz Province during an outbreak that lasted from June 2011 to August 2011. This study aimed to identify potential sources of transmission in order to determine suitable interventions in similar outbreaks. In other words, the lessons learned from this retrospective study can be utilized to manage future similar outbreaks. An age-matched and sex-matched case-control study was conducted during the outbreak. For each case, two control subjects were selected from the neighborhood. A case of cholera was defined as a bacteriologically confirmed case with signs and symptoms of cholera. This study was conducted from June 14, 2011 through August 23, 2011. The data were analyzed by calculating odds ratios (ORs) using the logistic regression method. In this outbreak, 229 confirmed cholera cases were diagnosed. The following risk factors were found to be associated with cholera: consumption of unrefrigerated leftover food (OR, 3.05; 95% confidence interval [CI], 1.72 to 5.41), consumption of vegetables and fruits in the previous three days (OR, 2.75; 95% CI, 1.95 to 3.89), and a history of traveling in the previous five days (OR, 5.31; 95% CI, 2.21 to 9.72). Consumption of vegetables and fruits has remained an unresolved risk factor in cholera outbreaks in Iran in recent years. In order to reduce the risk of cholera, sanitary standards for fruits and vegetables should be observed at all points from production to consumption, the population should be educated regarding hygienic food storage during outbreaks, and sanitary standards should be maintained when traveling during cholera outbreaks.

Should Controls With Respiratory Symptoms Be Excluded From Case-Control Studies of Pneumonia Etiology? Reflections From the PERCH Study

PubMed Central

Hammitt, Laura L.; Deloria Knoll, Maria; Baggett, Henry C.; Brooks, W. Abdullah; Howie, Stephen R. C.; Kotloff, Karen L.; Levine, Orin S.; Madhi, Shabir A.; Murdoch, David R.; Scott, J. Anthony G.; Thea, Donald M.; Driscoll, Amanda J.; Karron, Ruth A.; Park, Daniel E.; Prosperi, Christine; Zeger, Scott L.; O’Brien, Katherine L.; Feikin, Daniel R.; O’Brien, Katherine L.; Levine, Orin S.; Knoll, Maria Deloria; Feikin, Daniel R.; DeLuca, Andrea N.; Driscoll, Amanda J.; Fu, Wei; Hammitt, Laura L.; Higdon, Melissa M.; Kagucia, E. Wangeci; Karron, Ruth A.; Li, Mengying; Park, Daniel E.; Prosperi, Christine; Wu, Zhenke; Zeger, Scott L.; Watson, Nora L.; Crawley, Jane; Murdoch, David R.; Brooks, W. Abdullah; Endtz, Hubert P.; Zaman, Khalequ; Goswami, Doli; Hossain, Lokman; Jahan, Yasmin; Ashraf, Hasan; Howie, Stephen R. C.; Ebruke, Bernard E.; Antonio, Martin; McLellan, Jessica; Machuka, Eunice; Shamsul, Arifin; Zaman, Syed M.A.; Mackenzie, Grant; Scott, J. Anthony G.; Awori, Juliet O.; Morpeth, Susan C.; Kamau, Alice; Kazungu, Sidi; Kotloff, Karen L.; Tapia, Milagritos D.; Sow, Samba O.; Sylla, Mamadou; Tamboura, Boubou; Onwuchekwa, Uma; Kourouma, Nana; Toure, Aliou; Madhi, Shabir A.; Moore, David P.; Adrian, Peter V.; Baillie, Vicky L.; Kuwanda, Locadiah; Mudau, Azwifarwi; Groome, Michelle J.; Baggett, Henry C.; Thamthitiwat, Somsak; Maloney, Susan A.; Bunthi, Charatdao; Rhodes, Julia; Sawatwong, Pongpun; Akarasewi, Pasakorn; Thea, Donald M.; Mwananyanda, Lawrence; Chipeta, James; Seidenberg, Phil; Mwansa, James; wa Somwe, Somwe; Kwenda, Geoffrey

2017-01-01

Abstract Many pneumonia etiology case-control studies exclude controls with respiratory illness from enrollment or analyses. Herein we argue that selecting controls regardless of respiratory symptoms provides the least biased estimates of pneumonia etiology. We review 3 reasons investigators may choose to exclude controls with respiratory symptoms in light of epidemiologic principles of control selection and present data from the Pneumonia Etiology Research for Child Health (PERCH) study where relevant to assess their validity. We conclude that exclusion of controls with respiratory symptoms will result in biased estimates of etiology. Randomly selected community controls, with or without respiratory symptoms, as long as they do not meet the criteria for case-defining pneumonia, are most representative of the general population from which cases arose and the least subject to selection bias. PMID:28575354

[Risk factors for ischemic heart disease in Mexico: a case control study].

PubMed

Camacho-Hernández, R; Corona-Muñiz, I; Vázquez-Martínez, J L; Martínez-Rodríguez, F; Escobedo-de la Peña, J

1995-01-01

A case control study was developed in order to assess the strength of the association of modifiable risk factors and the occurrence of coronary heart disease in Mexicans. A total of 284 incident cases of acute myocardial infarction and 284 age and sex matched hospitalized controls were included in the study. Information was obtained in all subjects regarding socio-demographic variables, history of diabetes, hypertension, smoking, obesity and serum cholesterol. A conditional logistic regression model, showed that diabetes mellitus, hypertension, smoking, hypercholesterolemia and obesity, explained the occurrence of coronary heart disease in the studied population. The risk of an acute myocardial infarction heavily increases in the extreme levels of exposure; and this risk is six fold higher in those who daily smoke more than 20 cigarettes, and it is eight fold higher in those subjects with a serum cholesterol greater than 240 mg/dl. Due to the increase in the occurrence of coronary heart disease in Mexico, and the strength of the association observed with these modifiable risk factors, a public health program to decrease its prevalence, is justified.

Zika virus outbreak in New Caledonia and Guillain-Barré syndrome: a case-control study.

PubMed

Simon, Olivier; Acket, Blandine; Forfait, Carole; Girault, Dominique; Gourinat, Ann-Claire; Millon, Pauline; Daures, Maguy; Vanhomwegen, Jessica; Billot, Segolene; Biron, Antoine; Hoinard, Damien; Descloux, Elodie; Guyon, David; Manuguerra, Jean Claude; Laumond, Sylvie; Molko, Nicolas; Dupont-Rouzeyrol, Myrielle

2018-06-01

Zika virus (ZIKV) infection has been associated with neurologic disorders including Guillain-Barré syndrome (GBS). In New Caledonia during the ZIKV outbreak (2014-2015), case-control and retrospective studies have been performed to assess the link between ZIKV and GBS. Among the 15 cases included, 33% had evidence of a recent ZIKV infection compared to only 3.3% in the 30 controls involved. All patients were Melanesian, had facial diplegia and similar neurophysiological pattern consistent with acute inflammatory demyelinating polyneuropathy, and recovered well. Furthermore, during the peak of ZIKV transmission, we observed a number of GBS cases higher than the calculated upper limit, emphasizing the fact that ZIKV is now a major trigger of GBS.

Association between subthalamic nucleus deep brain stimulation and weight gain: Results of a case-control study.

PubMed

Strowd, Roy E; Herco, Maja; Passmore-Griffin, Leah; Avery, Bradley; Haq, Ihtsham; Tatter, Stephen B; Tate, Jessica; Siddiqui, Mustafa S

2016-01-01

To evaluate whether weight change in patients with Parkinson's disease (PD) is different in those undergoing deep brain stimulation (DBS) of the subthalamic nucleus (STN) compared to those not undergoing DBS. A retrospective case-control study was performed in PD patients who had undergone STN DBS (cases) compared to matched PD patients without DBS (controls). Demographic and clinical data including Unified Parkinson's Disease Rating Scale (UPDRS) motor scores were collected. Repeated measures mixed model regression was used to identify variables associated with weight gain. Thirty-five cases and 34 controls were identified. Baseline age, gender, diagnosis and weight were similar. Duration of diagnosis was longer in cases (6.3 vs 4.9 years, p=0.0015). At 21.3 months, cases gained 2.9 kg (+4.65%) while controls lost 1.8 kg (-3.05%, p<0.02). Postoperative UPDRS motor scores improved by 49% indicating surgical efficacy. Only younger age (p=0.0002) and DBS (p=0.008) were significantly associated with weight gain. In this case-control study, PD patients undergoing STN DBS experienced post-operative weight gain that was significantly different from the weight loss observed in non-DBS PD controls. Patients, especially overweight individuals, should be informed that STN DBS can result in weight gain. Copyright © 2015 Elsevier B.V. All rights reserved.

Hip fracture risk in relation to vitamin D supplementation and serum 25-hydroxyvitamin D levels: a systematic review and meta-analysis of randomised controlled trials and observational studies

PubMed Central

2010-01-01

Background Vitamin D supplementation for fracture prevention is widespread despite conflicting interpretation of relevant randomised controlled trial (RCT) evidence. This study summarises quantitatively the current evidence from RCTs and observational studies regarding vitamin D, parathyroid hormone (PTH) and hip fracture risk. Methods We undertook separate meta-analyses of RCTs examining vitamin D supplementation and hip fracture, and observational studies of serum vitamin D status (25-hydroxyvitamin D (25(OH)D) level), PTH and hip fracture. Results from RCTs were combined using the reported hazard ratios/relative risks (RR). Results from case-control studies were combined using the ratio of 25(OH)D and PTH measurements of hip fracture cases compared with controls. Original published studies of vitamin D, PTH and hip fracture were identified through PubMed and Web of Science databases, searches of reference lists and forward citations of key papers. Results The seven eligible RCTs identified showed no significant difference in hip fracture risk in those randomised to cholecalciferol or ergocalciferol supplementation versus placebo/control (RR = 1.13[95%CI 0.98-1.29]; 801 cases), with no significant difference between trials of <800 IU/day and ≥800 IU/day. The 17 identified case-control studies found 33% lower serum 25(OH)D levels in cases compared to controls, based on 1903 cases. This difference was significantly greater in studies with population-based compared to hospital-based controls (χ21 (heterogeneity) = 51.02, p < 0.001) and significant heterogeneity was present overall (χ216 (heterogeneity) = 137.9, p < 0.001). Serum PTH levels in hip fracture cases did not differ significantly from controls, based on ten case-control studies with 905 cases (χ29 (heterogeneity) = 149.68, p < 0.001). Conclusions Neither higher nor lower dose vitamin D supplementation prevented hip fracture. Randomised and observational data on vitamin D and hip fracture appear to

Sources of heterogeneity in case-control studies on associations between statins, ACE-inhibitors, and proton pump inhibitors and risk of pneumonia.

PubMed

de Groot, Mark C H; Klungel, Olaf H; Leufkens, Hubert G M; van Dijk, Liset; Grobbee, Diederick E; van de Garde, Ewoudt M W

2014-10-01

The heterogeneity in case-control studies on the associations between community-acquired pneumonia (CAP) and ACE-inhibitors (ACEi), statins, and proton pump inhibitors (PPI) hampers translation to clinical practice. Our objective is to explore sources of this heterogeneity by applying a common protocol in different data settings. We conducted ten case-control studies using data from five different health care databases. Databases varied on type of patients (hospitalised vs. GP), level of case validity, and mode of exposure ascertainment (prescription or dispensing based). Identified CAP patients and controls were matched on age, gender, and calendar year. Conditional logistic regression was used to calculate odds ratios (OR) for the associations between the drugs of interest and CAP. Associations were adjusted by a common set of potential confounders. Data of 38,742 cases and 118,019 controls were studied. Comparable patterns of variation between case-control studies were observed for ACEi, statins and PPI use and pneumonia risk with adjusted ORs varying from 1.04 to 1.49, 0.82 to 1.50 and 1.16 to 2.71, respectively. Overall, higher ORs were found for hospitalised CAP patients matched to population controls versus GP CAP patients matched to population controls. Prevalence of drug exposure was higher in dispensing data versus prescription data. We show that case-control selection and methods of exposure ascertainment induce bias that cannot be adjusted for and to a considerable extent explain the heterogeneity in results obtained in case-control studies on statins, ACEi and PPIs and CAP. The common protocol approach helps to better understand sources of variation in observational studies.

Hyperthyroidism and erectile dysfunction: a population-based case-control study.

PubMed

Keller, J; Chen, Y-K; Lin, H-C

2012-01-01

Dysthyroidism has been highlighted as a common endocrine disorder associated with erectile dysfunction (ED); however, to date, no large-scale population-based study has investigated the association between hyperthyroidism and ED. This case-control study aimed to explore the association between ED and hyperthyroidism using a population-based data set. In total, 6310 adult patients who received new diagnoses of ED were recruited as cases together with 18 930 matched enrollees with no history of ED who served as controls. Conditional logistic regressions were conducted to explore the association between ED and having been previously diagnosed with hyperthyroidism. In total, 569 (2.3%) of the 25 240 sampled subjects had been diagnosed with hyperthyroidism before the index date; hyperthyroidism was found in 207 (3.3%) cases and 362 (1.90%) controls. After adjusting for potential confounding factors, the odds ratio (OR) of prior hyperthyroidism among cases was 1.64 (95% confidence interval=1.37-1.96, P<0.001) than that of controls. No association was detected between prior hyperthyroidism and ED for the 18-30, 30-39 and >70 age groups. Subjects aged between 60 and 69 years had the highest ORs for prior hyperthyroidism among cases when compared to controls (OR=1.84; 95% confidence interval=1.20-2.84; P<0.001). Our study further confirms the existence of an association between ED and prior hyperthyroidism.

Case-control study of surgical site infections associated with pacemakers and implantable cardioverter-defibrillators.

PubMed

Marschall, Jonas; Hopkins-Broyles, Diane; Jones, Marilyn; Fraser, Victoria J; Warren, David K

2007-11-01

In 2000, the rate of surgical site infections (SSIs) associated with pacemaker and implantable cardioverter-defibrillator (ICD) procedures performed in the cardiothoracic operating rooms of hospital A was 16% (19 of 116 procedures resulted in infections). This study investigates risks for SSI associated with these procedures in the cardiothoracic operating room. Unmatched 1 : 3 case-control study performed over a 12-month period among patients who had undergone implantation of a pacemaker and/or ICD. A standardized observation scrutinized infection control practices in the area where the procedures were performed. The cardiothoracic operating rooms of hospital A, which belongs to a hospital consortium in the midwestern United States. Patients with SSI were identified as case patients. Control patients were chosen from the group of uninfected patients who had procedures performed during the same period as case patients. A total of 19 SSIs associated with pacemaker and ICD procedures were retrospectively identified among the patients who underwent procedures in these cardiothoracic operating rooms. Culture samples were obtained from 7 patients; 2 yielded coagulase-negative Staphylococcus on culture, 2 yielded Staphylococcus aureus, 1 yielded Serratia marcescens, and 2 showed no growth. In the case-control study, age, race, sex, diabetes mellitus, smoking history, timing of antibiotic therapy, and hair removal did not differ significantly between case patients and control patients. Case patients were more likely to have an abdominal device in place (odds ratio [OR], 5.5 [95% confidence interval {CI}, 1.6-19.3]; P=.006) and less likely to have received a new implant (OR 0.3 [95% CI, 0.1-0.8]; P=.02) or to have had new leads placed (OR, 0.2 [95% CI, 0.1-0.6]; P=.003). Abdominal placement of implanted devices was associated with occurrence of an SSI after pacemaker and/or ICD procedures.

Lack of association between migraine headache and patent foramen ovale: results of a case-control study.

PubMed

Garg, Pallav; Servoss, Stephen J; Wu, Justina C; Bajwa, Zahid H; Selim, Magdy H; Dineen, Alexis; Kuntz, Richard E; Cook, E Francis; Mauri, Laura

2010-03-30

Clinical observations of migraine headache symptoms in patients with a patent foramen ovale (PFO), both of which conditions are highly prevalent, have raised the question of a possible pathophysiological relationship. We sought to evaluate the assumption of an association between migraine headaches and the presence of PFO by use of a large case-control study. We conducted a case-control study to assess the prevalence of PFO in subjects with and without migraine. Case subjects were those with a history of migraine (diagnosed by neurologists at a specialty academic headache clinic). Control subjects were healthy volunteers without migraine 1:1 matched on the basis of age and sex with case subjects. Presence of PFO was determined by transthoracic echocardiogram with second harmonic imaging and transcranial Doppler ultrasonography during a standardized procedure of infused agitated saline contrast with or without Valsalva maneuver and a review of the results by experts blinded to case-control status. PFO was considered present if both studies were positive. Odds ratios were calculated with conditional logistic regression in the matched cohort (n=288). In the matched analysis, the prevalence of PFO was similar in case and control subjects (26.4% versus 25.7%; odds ratio 1.04, 95% confidence interval 0.62 to 1.74, P=0.90). There was no difference in PFO prevalence in those with migraine with aura and those without (26.8% versus 26.1%; odds ratio 1.03, 95% confidence interval 0.48 to 2.21, P=0.93). We found no association between migraine headaches and the presence of PFO in this large case-control study.

Apolipoprotein E in Temporal Lobe Epilepsy: A Case-Control Study

PubMed Central

Kumar, Amit; Tripathi, Manjari; Pandey, Ravindra M.; Ramakrishnan, Lakshmy; Srinivas, M.; Luthra, Kalpana

2006-01-01

Purpose: To investigate the relationship of apolipoprotein E (apoE) genotype, plasma levels of apoE and lipids in temporal lobe epilepsy (TLE) patients in Asian Indians. Status of plasma levels of Apo E in epilepsy patients has not been reported till date. Methods: ApoE gene polymorphism was analyzed in 58 patients with temporal lobe epilepsy (TLE) and 57 age and sex approximated controls using Polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP). Levels of plasma apoE and lipids were measured using ELISA and enzymatic kits respectively. Results: The distribution of ApoE genotype in epilepsy patients and controls was comparable. Higher levels of plasma ApoE were observed in TLE patients as compared to controls (p = 0.0001). Individuals with plasma levels of apoE > 190 mg/L were at 20 times higher odds (95%CI = 2.46–163.34, p = 0.005), while those with levels of apoE between 150–190 mg/L were at 4.9 times higher odds (95% CI = 1.85–13.9, p = 0.001), to develop TLE. Conclusions: We have observed for the first time, high levels of plasma apoE in epilepsy patients. The findings of this case-control study suggest that apolipoprotein E may play an important role in epilepsy. PMID:17264404

Injury case-control studies using "other injuries" as controls.

PubMed

Marshall, Stephen W

2008-03-01

Studies of event-related (or "event-phase") interventions (such as ski helmets) can address injury at a specific body site (such as the head) by using as controls a group of people who experienced the same event (fall) and suffered injuries at other body sites (other than the head). The research question addressed by this type of study is the effect of an exposure or intervention (helmet) during the event phase (fall) of the causal chain. However, this is a valid case-control design only if the controls (skiers with other injuries) provide a reasonable proxy for the prevalence of exposure (helmet-wearing) in the underlying event-phase source population (skiers who fell). This assumption needs to be carefully assessed. Factors associated with both helmet-wearing and injury given a fall (eg, previous injury history, skiing inexperience, or risk-taking behavior) have considerable potential to create bias.

Black tobacco, wine and mate in oropharyngeal cancer. A case-control study from Uruguay.

PubMed

De Stefani, E; Correa, P; Oreggia, F; Deneo-Pellegrini, H; Fernandez, G; Zavala, D; Carzoglio, J; Leiva, J; Fontham, E; Rivero, S

1988-01-01

A case-control study of oral and pharyngeal cancer involving interviews with 108 cases and 286 controls was carried out in the University Hospital of Montevideo, Uruguay. The study was restricted to males and cases afflicted with lip, salivary gland and nasopharyngeal cancer were excluded. Point estimates of RR associated with smoking variables, alcohol variables, nutritional items and ingestion of hot infusions of the herb Ilex paraguariensis ('Mate') were obtained by logistic regression analysis. Dark tobacco smokers showed a RR 3.4 times higher than light tobacco users and heavy drinkers of wine displayed an OR of 17.2. Mate exposure showed a significant dose-response, after adjustment for age, tobacco and alcohol intake, with a fivefold increase in risk for heavy consumers. Joint exposure to black tobacco and wine displayed very high risks and no significant interactions were observed. The results suggest that the high rates of oropharyngeal cancer could be explained by the multiplicative effect of black tobacco smoking, wine drinking and mate ingestion.

Toxocariasis and childhood asthma: A case-control study.

PubMed

Cadore, Priscila Silva; Zhang, Linjie; Lemos, Liliam de Lima; Lorenzi, Carolina; Telmo, Paula de Lima; Dos Santos, Paula Costa; Mattos, Gabriela Torres; Vignol, Flávia Saraçol; Prietsch, Silvio O M; Berne, Maria Elisabeth Aires; Scaini, Carlos James

2016-08-01

The objective of this study is to investigate the association between anti-Toxocara IgG seropositivity and asthma in children. This was a case-control study conducted in a university hospital in south Brazil between May 2012 and June 2013. Were recruited 208 children up to 12 years old of whom 156 had asthma (cases) and 52 did not have asthma (controls), with a case-control ratio of 3:1 matched by age. Children's parents or guardians were interviewed using a structured questionnaire with closed questions. Serology was performed using enzyme-linked immunosorbent assay (ELISA) with excretory-secretory antigen of Toxocara canis (TES). The seroprevalence of IgG anti-T. canis antibodies was 12.8% in the cases and 7.7% in the controls. There was no significant association between seropositivity to T. canis and risk of asthma (adjusted odds ratio [OR]: 1.89, 95% CI: 0.52 to 6.89, p = 0.33). Household income < 2 minimum salaries, paternal school years < 9, allergic rhinitis in children, a positive family history of asthma and rhinitis and contact with cats were significantly associated with asthma, with adjusted ORs (95% CIs) of 3.05 (1.21 to 7.73), 2.83 (1.11 to 7.18), 10.5 (4.32 to 25.6), 2.65 (1.14 to 6.17), 2.49 (1.07 to 5.78) and 2.73 (1.03 to 7.27), respectively. This study did not find a statistically significant association between seropositivity to Toxocara sp. and risk of asthma in children. Low family income, low paternal education level, concomitant allergic rhinitis, family history of asthma and allergic rhinitis and contact with cats were independent factors associated with childhood asthma.

Ticagrelor and bradycardia: a nested case-control study.

PubMed

Turgeon, Ricky D; Fernandes, Kimberly A; Juurlink, David; Tu, Jack V; Mamdani, Muhammad

2015-12-01

Ticagrelor increases serum adenosine concentrations, slowing conduction and possibly leading to bradycardia. Clinical trial data have shown numerically, though not statistically significantly, higher rates of bradyarrhythmias with ticagrelor versus clopidogrel. Additionally, recent case reports have further raised concerns for this adverse effect. We explored the association between ticagrelor and hospitalization for bradycardia in a real-world setting. We conducted a population-based, nested case-control study of Ontario residents, 66 years of age or older, discharged after a first acute coronary syndrome by linking multiple healthcare databases. Cases included patients hospitalized for bradycardia within 1 year of starting a P2Y12 inhibitor. For each case, we identified 4 controls matched on age, sex, index date, and current use of a P2Y12 inhibitor. The exposure of interest was a prescription for ticagrelor within 90 days, with clopidogrel use as the reference group. From April 2012 to March 2014, we identified 140 cases and 560 controls who met the study criteria. We found no significant association between bradycardia and exposure to ticagrelor relative to clopidogrel in the previous 90 days prior to the index date (adjusted odds ratio 1.06, 95% confidence interval 0.65-2.21). Further adjustment for potential confounders also did not identify a significant association. Among older patients with a first acute coronary syndrome, use of ticagrelor was not associated with a greater risk of admission for bradycardia relative to clopidogrel. Copyright © 2015 John Wiley & Sons, Ltd.

Modified directly observed treatment for tuberculosis versus self-administered therapy: an observational study in rural Greece.

PubMed

Charokopos, N; Tsiros, G; Foka, A; Voila, P; Chrysanthopoulos, K; Spiliopoulou, I; Jelastopulu, E

2013-01-01

Directly Observed Treatment (DOT) is the key element of DOTS (directly observed treatment, short course), part of the internationally recommended control strategy for tuberculosis (TB). The evaluation of DOT has not been widely evaluated in rural areas in developed settings. The aim of this pilot study was to evaluate a modified DOT program (MDOT) by a general practitioner (GP) in a rural area of southwest Greece, where there is substantial underreporting of TB cases. Thirteen new TB cases with 30 close contacts were compared with 41 past-treated TB subjects (controls) with 111 close contacts in this observational, case-control study. Home visits by a GP were conducted and comparison of various data (laboratory findings, treatment outcomes, questionnaire-based parameters, on-site recorded conditions) was performed in both newly detected pulmonary TB cases and previously treated TB cases managed without DOT intervention. MDOT by GP implementation revealed that 11 cases (84.6%) were successfully treated, one (7.7%) case died, and one (7.7%) was lost to follow up. None of the close contacts of new TB cases was infected with active TB, while 6.3% of previously-treated TB subjects were infected with active TB and had to receive a complete anti-TB regimen. Chemoprophylaxis was administered to 13.3% of close contacts of new cases; whereas 12.6% of close contacts of previously-treated patients received chemoprophylaxis. This pilot study revealed that a GP is able to implement a program based on DOT resulting in high treatment adherence and prevention of TB compared with the conventional self-administration of treatment.

A prevalence-based association test for case-control studies.

PubMed

Ryckman, Kelli K; Jiang, Lan; Li, Chun; Bartlett, Jacquelaine; Haines, Jonathan L; Williams, Scott M

2008-11-01

Genetic association is often determined in case-control studies by the differential distribution of alleles or genotypes. Recent work has demonstrated that association can also be assessed by deviations from the expected distributions of alleles or genotypes. Specifically, multiple methods motivated by the principles of Hardy-Weinberg equilibrium (HWE) have been developed. However, these methods do not take into account many of the assumptions of HWE. Therefore, we have developed a prevalence-based association test (PRAT) as an alternative method for detecting association in case-control studies. This method, also motivated by the principles of HWE, uses an estimated population allele frequency to generate expected genotype frequencies instead of using the case and control frequencies separately. Our method often has greater power, under a wide variety of genetic models, to detect association than genotypic, allelic or Cochran-Armitage trend association tests. Therefore, we propose PRAT as a powerful alternative method of testing for association.

Fall Hazards Within Senior Independent Living: A Case-Control Study.

PubMed

Kim, Daejin; Portillo, Margaret

2018-01-01

The main purpose of this research was to identify significant relationships between environmental hazards and older adults' falling. Falls can present a major health risk to older persons. Identifying potential environmental hazards that increase fall risks can be effective for developing fall prevention strategies that can create safer residential environments for older adults. The research included a retrospective analysis of 449 fall incident reports in two case-control buildings. In the homes of 88 older adults residing in independent living, an observational study was conducted to identify environmental hazards using two assessment tools including Westmead Home Safety Assessment (WeHSA) and resident interviews. A fall history analysis indicated that falls occurred in the bathroom were significantly associated with hospitalization. The observational study revealed that the bathroom was the most common place for environmental hazards. The research showed, with increasing age and use of mobility assistive aids, there was a corresponding increase in the total number of environmental hazards. Home hazards were significantly and independently associated with the incidence rate of falls. In other words, the high fall rate building included more environmental hazards compared to the low fall rate building while controlling for residents' age and mobility. The current study provides empirical evidence of the link between environmental hazards and older adults' falling, which is useful for developing effective fall intervention design strategies.

High risk of brain tumors in military personnel: a case control study.

PubMed

Fallahi, P; Elia, G; Foddis, R; Cristaudo, A; Antonelli, A

2017-01-01

Scientific literature suggests a relationship between military occupation and the development of brain tumors, but no italian study has investigated on the impact of this job on the brain cancer morbidity. In this a study information were obtained from patients recruited in the Neurosurgical Department of the University-Hospital of Pisa, Italy, from 1990 to 1999. The study has been conducted as a case-control study. 161, newly diagnosed cases of brain tumors (glioma and meningiomas, histologically confirmed), were recruited, such as 483 controls (with other non tumoral neurologic diseases: trauma, hemorrhagic brain disorders, aneurism, etc), by matching cases and controls (1:3), for age (± 5 years) and gender. Cases and controls were interviewed in the Neurosurgical Department, University-Hospital of Pisa, Italy, and the occupational histories of cases and controls were compared. Cases and controls have showed a statistically significant difference, based on their occupation (military vs. non-military occupation). A statistically significant association was seen between brain tumors and military occupation among evaluated patients (p=0.013). Further studies regarding this population group are needed, to determine the causes for the increased risk of this cancer. Furthermore, a subsequent reevaluation in other patients collected in more recent years will be needed to evaluate the trend of this association.

Should Controls With Respiratory Symptoms Be Excluded From Case-Control Studies of Pneumonia Etiology? Reflections From the PERCH Study.

PubMed

Higdon, Melissa M; Hammitt, Laura L; Deloria Knoll, Maria; Baggett, Henry C; Brooks, W Abdullah; Howie, Stephen R C; Kotloff, Karen L; Levine, Orin S; Madhi, Shabir A; Murdoch, David R; Scott, J Anthony G; Thea, Donald M; Driscoll, Amanda J; Karron, Ruth A; Park, Daniel E; Prosperi, Christine; Zeger, Scott L; O'Brien, Katherine L; Feikin, Daniel R

2017-06-15

Many pneumonia etiology case-control studies exclude controls with respiratory illness from enrollment or analyses. Herein we argue that selecting controls regardless of respiratory symptoms provides the least biased estimates of pneumonia etiology. We review 3 reasons investigators may choose to exclude controls with respiratory symptoms in light of epidemiologic principles of control selection and present data from the Pneumonia Etiology Research for Child Health (PERCH) study where relevant to assess their validity. We conclude that exclusion of controls with respiratory symptoms will result in biased estimates of etiology. Randomly selected community controls, with or without respiratory symptoms, as long as they do not meet the criteria for case-defining pneumonia, are most representative of the general population from which cases arose and the least subject to selection bias. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

Lifestyle factors and risk of leukemia and non-Hodgkin's lymphoma: a case-control study.

PubMed

Parodi, Stefano; Santi, Irene; Marani, Enza; Casella, Claudia; Puppo, Antonella; Garrone, Elsa; Fontana, Vincenzo; Stagnaro, Emanuele

2016-03-01

Risk factors for leukemia and lymphomas in adults are largely unknown. This study was aimed at evaluating the association between lifestyle factors and the risk of hematological malignancies in an adult population. Data were drawn from a population-based case-control study carried out in Italy and included 294 cases (199 lymphoid and 95 myeloid) and 279 controls. Analyses were performed using standard multivariable logistic regression. Hair dye use for at least 15 years was associated with a higher risk of lymphoid malignancies among females (OR 2.3, 95 % CI 1.0-4.9, p = 0.036, test for trend). Furthermore, a protective effect of a moderate to heavy tea consumption on the risk of myeloid malignancies was observed (OR 0.4, 95 % CI 0.2-0.9, p = 0.017). No association was found for the use of alcoholic beverages and tobacco smoking. Our results confirm the potential carcinogenic effect of prolonged hair dye use observed in previous investigations. The excess risk could be explained by exposure to a higher concentration of toxic compounds in hair products used in the past. The protective effect of regular tea consumption observed in an area with a very high prevalence of black tea consumers deserves further investigation.

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: guidelines for reporting observational studies.

PubMed

von Elm, Erik; Altman, Douglas G; Egger, Matthias; Pocock, Stuart J; Gøtzsche, Peter C; Vandenbroucke, Jan P

2014-12-01

Much biomedical research is observational. The reporting of such research is often inadequate, which hampers the assessment of its strengths and weaknesses and of a study's generalisability. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Initiative developed recommendations on what should be included in an accurate and complete report of an observational study. We defined the scope of the recommendations to cover three main study designs: cohort, case-control, and cross-sectional studies. We convened a 2-day workshop in September 2004, with methodologists, researchers, and journal editors to draft a checklist of items. This list was subsequently revised during several meetings of the coordinating group and in e-mail discussions with the larger group of STROBE contributors, taking into account empirical evidence and methodological considerations. The workshop and the subsequent iterative process of consultation and revision resulted in a checklist of 22 items (the STROBE Statement) that relate to the title, abstract, introduction, methods, results, and discussion sections of articles. 18 items are common to all three study designs and four are specific for cohort, case-control, or cross-sectional studies. A detailed Explanation and Elaboration document is published separately and is freely available on the Web sites of PLoS Medicine, Annals of Internal Medicine, and Epidemiology. We hope that the STROBE Statement will contribute to improving the quality of reporting of observational studies. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Cruciferous vegetable intake is inversely associated with lung cancer risk among smokers: a case-control study

PubMed Central

2010-01-01

Background Inverse associations between cruciferous vegetable intake and lung cancer risk have been consistently reported. However, associations within smoking status subgroups have not been consistently addressed. Methods We conducted a hospital-based case-control study with lung cancer cases and controls matched on smoking status, and further adjusted for smoking status, duration, and intensity in the multivariate models. A total of 948 cases and 1743 controls were included in the analysis. Results Inverse linear trends were observed between intake of fruits, total vegetables, and cruciferous vegetables and risk of lung cancer (ORs ranged from 0.53-0.70, with P for trend < 0.05). Interestingly, significant associations were observed for intake of fruits and total vegetables with lung cancer among never smokers. Conversely, significant inverse associations with cruciferous vegetable intake were observed primarily among smokers, in particular former smokers, although significant interactions were not detected between smoking and intake of any food group. Of four lung cancer histological subtypes, significant inverse associations were observed primarily among patients with squamous or small cell carcinoma - the two subtypes more strongly associated with heavy smoking. Conclusions Our findings are consistent with the smoking-related carcinogen-modulating effect of isothiocyanates, a group of phytochemicals uniquely present in cruciferous vegetables. Our data support consumption of a diet rich in cruciferous vegetables may reduce the risk of lung cancer among smokers. PMID:20423504

Family clustering of secondary chronic kidney disease with hypertension or diabetes mellitus. A case-control study.

PubMed

de Almeida, Fernando Antonio; Ciambelli, Giuliano Serafino; Bertoco, André Luz; Jurado, Marcelo Mai; Siqueira, Guilherme Vasconcelos; Bernardo, Eder Augusto; Pavan, Maria Valeria; Gianini, Reinaldo José

2015-02-01

In Brazil hypertension and type 2 diabetes mellitus are responsible for 60% of cases of end-stage renal disease in renal replacement therapy. In the United States studies have identified family clustering of chronic kidney disease, predominantly in African-Americans. A single Brazilian study observed family clustering among patients with chronic kidney disease when compared with hospitalized patients with normal renal function. This article aims to assess whether there is family clustering of chronic kidney disease in relatives of individuals in renal replacement therapy caused by hypertension and/or diabetes mellitus. A case-control study with 336 patients in renal replacement therapy with diabetes mellitus or hypertension for at least 5 years (cases) and a control matched sample group of individuals with hypertension or diabetes mellitus and normal renal function (n = 389). Individuals in renal replacement therapy (cases) had a ratio of 2.35 (95% CI 1.42-3.89, p < 0.001) versus the control group in having relatives with chronic renal disease, irrespective of race or causative illness. There is family clustering of chronic kidney disease in the sample studied, and this predisposition is irrespective of race and underlying disease (hypertension or diabetes mellitus).

Level of neurotoxic metals in amyotrophic lateral sclerosis: A population-based case-control study.

PubMed

Bocca, Beatrice; Forte, Giovanni; Oggiano, Riccardo; Clemente, Simonetta; Asara, Yolande; Peruzzu, Angela; Farace, Cristiano; Pala, Salvatore; Fois, Alessandro Giuseppe; Pirina, Pietro; Madeddu, Roberto

2015-12-15

The association between exposure to toxic metals and amyotrophic lateral sclerosis (ALS) was explored in a population-based case-control study in the Sardinia island (Italy), a region characterized by elevated rates of ALS cases. In 34 patients with ALS (mean age, 62 ± 10 years) and 30 controls (mean age, 65 ± 11 years), Al, Cd, Hg, Mn and Pb were determined in blood, hair and urine by sector field inductively coupled mass spectrometry. Results indicated that, in blood, concentrations of Al (p=0.045) and Pb were higher (p=0.026) in ALS patients than in control subjects. In hair, a depletion of Al (p=0.006) and Mn (p=0.032) concentrations in ALS subjects respect to controls was found. In urine, no significant differences between cases and controls were observed. Thus, some metals seemed to be associated with ALS degeneration, but a definitive conclusion is still far considering the multiple risk factors (genetic mutations, environmental toxicants and stressors) involved in the disease. Finally, the interpretation that deregulated metal concentrations can be a consequence of the degenerative process, rather than a cause, is also valid. Copyright © 2015 Elsevier B.V. All rights reserved.

A case-control study of gastric cancer in Venezuela.

PubMed

Muñoz, N; Plummer, M; Vivas, J; Moreno, V; De Sanjosé, S; Lopez, G; Oliver, W

2001-08-01

A case-control study to evaluate risk factors for gastric cancer was carried out among 292 cases of gastric cancer and 485 controls in a high-risk area of Venezuela. Subjects were interviewed using a structured questionnaire, which elicited information on residential history, socio-economic status, family history of gastric diseases, smoking, drinking and dietary habits. Habitual diet was estimated from a meal-structured food frequency questionnaire on 75 food items. There was a strong inverse association with social class, as measured by education and by indicators of poverty. The results of the dietary analysis suggest that a diet high in starch and low in meat, fish and fresh vegetables increases risk of gastric cancer. A protective effect was observed for frequent consumption of allium vegetables. Inverse associations were found with height, which may reflect nutritional status in childhood, and with refrigerator use in the first two decades of life. Alcohol and tobacco consumption was investigated among males only, since the prevalence of alcohol and tobacco use was very low in females. Alcohol drinkers were at higher risk than non-drinkers and there was a small excess risk for current smokers compared with never smokers. There was some evidence of familial aggregation of gastric cancer. These findings will have important implications in planning preventive strategies for gastric cancer in Venezuela. Copyright 2001 Wiley-Liss, Inc.

Hypothyroidism among SLE patients: Case-control study.

PubMed

Watad, Abdulla; Mahroum, Naim; Whitby, Aaron; Gertel, Smadar; Comaneshter, Doron; Cohen, Arnon D; Amital, Howard

2016-05-01

The prevalence of hypothyroidism in SLE patients varies considerably and early reports were mainly based on small cohorts. To investigate the association between SLE and hypothyroidism. Patients with SLE were compared with age and sex-matched controls regarding the proportion of hypothyroidism in a case-control study. Chi-square and t-tests were used for univariate analysis and a logistic regression model was used for multivariate analysis. The study was performed utilizing the medical database of Clalit Health Services. The study included 5018 patients with SLE and 25,090 age and sex-matched controls. The proportion of hypothyroidism in patients with SLE was increased compared with the prevalence in controls (15.58% and 5.75%, respectively, P<0.001). In a multivariate analysis, SLE was associated with hypothyroidism (odds ratio 2.644, 95% confidence interval 2.405-2.908). Patients with SLE have a greater proportion of hypothyroidism than matched controls. Therefore, physicians treating patients with SLE should be aware of the possibility of thyroid dysfunction. Copyright © 2016 Elsevier B.V. All rights reserved.

Gut microbiota in early pediatric multiple sclerosis: a case-control study.

PubMed

Tremlett, Helen; Fadrosh, Douglas W; Faruqi, Ali A; Zhu, Feng; Hart, Janace; Roalstad, Shelly; Graves, Jennifer; Lynch, Susan; Waubant, Emmanuelle

2016-08-01

Alterations in the gut microbial community composition may be influential in neurological disease. Microbial community profiles were compared between early onset pediatric multiple sclerosis (MS) and control children similar for age and sex. Children ≤18 years old within 2 years of MS onset or controls without autoimmune disorders attending a University of California, San Francisco, USA, pediatric clinic were examined for fecal bacterial community composition and predicted function by 16S ribosomal RNA sequencing and phylogenetic reconstruction of unobserved states (PICRUSt) analysis. Associations between subject characteristics and the microbiota, including beta diversity and taxa abundance, were identified using non-parametric tests, permutational multivariate analysis of variance and negative binomial regression. Eighteen relapsing-remitting MS cases and 17 controls (mean age 13 years; range 4-18) were studied. Cases had a short disease duration (mean 11 months; range 2-24) and half were immunomodulatory drug (IMD) naïve. Whilst overall gut bacterial beta diversity was not significantly related to MS status, IMD exposure was (Canberra, P < 0.02). However, relative to controls, MS cases had a significant enrichment in relative abundance for members of the Desulfovibrionaceae (Bilophila, Desulfovibrio and Christensenellaceae) and depletion in Lachnospiraceae and Ruminococcaceae (all P and q < 0.000005). Microbial genes predicted as enriched in MS versus controls included those involved in glutathione metabolism (Mann-Whitney, P = 0.017), findings that were consistent regardless of IMD exposure. In recent onset pediatric MS, perturbations in the gut microbiome composition were observed, in parallel with predicted enrichment of metabolic pathways associated with neurodegeneration. Findings were suggestive of a pro-inflammatory milieu. © 2016 EAN.

Neospora caninum versus Brucella spp. exposure among dairy cattle in Ethiopia: a case control study.

PubMed

Asmare, Kassahun

2014-08-01

This case-control study aimed at assessing the relative association of Neospora caninum and Brucella species exposure with reproductive disorders. The study was carried out between October 2011 and June 2012 on 731 dairy cows sampled from 150 dairy farms in selected 17 conurbations of Ethiopia. Two hundred sixty-six of the cows were categorized as cases based on their history of abortion or stillbirth while the remaining 465 were controls. The presence of antibody to N. caninum was screened using indirect ELISA, while Brucella spp. exposure was assayed serially using Rose Bengal Plate Test and Complement Fixation Test. Exposure to N. caninum was more frequently observed among cases (23.8%) than controls (12.7%), while no significant difference (p > 0.05) was noted for Brucella exposure between the two groups. Moreover, the proportion of cows with disorders like retention of fetal membrane, endometritis and increased inter-calving period were significantly higher (p < 0.05) among Neospora seropositive cows. In conclusion, the finding discloses the strong association of N. caninum with reproductive disorders compared to Brucella spp. exposure. However, neither N. caninum nor Brucella spp. could explain the majority (73.2%) of the reported abortions and stillbirths in cattle. Hence, this observation underscores the need for more intensive investigation on the identification of causes of the aforementioned disorders in dairy cattle of Ethiopia.

Occupational exposure to metals and risk of meningioma: a multinational case-control study.

PubMed

Sadetzki, Siegal; Chetrit, Angela; Turner, Michelle C; van Tongeren, Martie; Benke, Geza; Figuerola, Jordi; Fleming, Sarah; Hours, Martine; Kincl, Laurel; Krewski, Daniel; McLean, Dave; Parent, Marie-Elise; Richardson, Lesley; Schlehofer, Brigitte; Schlaefer, Klaus; Blettner, Maria; Schüz, Joachim; Siemiatycki, Jack; Cardis, Elisabeth

2016-12-01

The aim of the study was to examine associations between occupational exposure to metals and meningioma risk in the international INTEROCC study. INTEROCC is a seven-country population-based case-control study including 1906 adult meningioma cases and 5565 population controls. Incident cases were recruited between 2000 and 2004. A detailed occupational history was completed and job titles were coded into standard international occupational classifications. Estimates of mean workday exposure to individual metals and to welding fumes were assigned based on a job-exposure-matrix. Adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) were estimated using conditional logistic regression. Although more controls than cases were ever exposed to metals (14 vs. 11 %, respectively), cases had higher median cumulative exposure levels. The ORs for ever vs. never exposure to any metal and to individual metals were mostly greater than 1.0, with the strongest association for exposure to iron (OR 1.26, 95 % CI 1.0-1.58). In women, an increased OR of 1.70 (95 % CI 1.0-2.89) was seen for ever vs never exposure to iron (OR in men 1.19, 95 % CI 0.91-1.54), with positive trends in relation with both cumulative and duration of exposure. These results remained after consideration of other occupational metal or chemical co-exposures. In conclusion, an apparent positive association between occupational exposure to iron and meningioma risk was observed, particularly among women. Considering the fact that meningioma is a hormone dependent tumor, the hypothesis that an interaction between iron and estrogen metabolism may be a potential mechanism for a carcinogenic effect of iron should be further investigated.

Case-control study of dementia of the Alzheimer type

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

French, L.R.; Schuman, L.M.; Mortimer, J.A.

1985-03-01

A case-control study to assess factors of possible etiologic significance to dementia of the Alzheimer type was conducted with 78 male cases diagnosed in 1979-1982 at the Veterans Administration Medical Center in Minneapolis, Minnesota and age-race-sex-matched hospital and neighborhood controls (14 of 16 autopsied cases were histopathologically confirmed). Information was obtained on variables relevant to vital, genetic, and immunologic hypotheses, and on possible occupational and environmental exposures, drug use, psychologic stress, smoking, and alcohol consumption. The only major difference between patients with dementia of the Alzheimer type and controls was a significantly greater occurrence of antecedent head trauma in themore » patients (odds ratio = 4.50). This finding is consistent with the literature on posttraumatic dementia but its importance is presently unclear.« less

CONTROL FUNCTION ASSISTED IPW ESTIMATION WITH A SECONDARY OUTCOME IN CASE-CONTROL STUDIES.

PubMed

Sofer, Tamar; Cornelis, Marilyn C; Kraft, Peter; Tchetgen Tchetgen, Eric J

2017-04-01

Case-control studies are designed towards studying associations between risk factors and a single, primary outcome. Information about additional, secondary outcomes is also collected, but association studies targeting such secondary outcomes should account for the case-control sampling scheme, or otherwise results may be biased. Often, one uses inverse probability weighted (IPW) estimators to estimate population effects in such studies. IPW estimators are robust, as they only require correct specification of the mean regression model of the secondary outcome on covariates, and knowledge of the disease prevalence. However, IPW estimators are inefficient relative to estimators that make additional assumptions about the data generating mechanism. We propose a class of estimators for the effect of risk factors on a secondary outcome in case-control studies that combine IPW with an additional modeling assumption: specification of the disease outcome probability model. We incorporate this model via a mean zero control function. We derive the class of all regular and asymptotically linear estimators corresponding to our modeling assumption, when the secondary outcome mean is modeled using either the identity or the log link. We find the efficient estimator in our class of estimators and show that it reduces to standard IPW when the model for the primary disease outcome is unrestricted, and is more efficient than standard IPW when the model is either parametric or semiparametric.

[Case-control study on influence factors of birth defects].

PubMed

Xiu, Xin-hong; Yuan, Li; Wang, Xiao-ming; Chen, Yu-hua; Wan, Ai-hua; Fu, Ping

2011-07-01

To investigate the influence factors of birth defects. The congenital malformational fetuses born from 13 week of gestation to 7 days after birth were selected as the study group between April 1st, 2009 and March 31st, 2010. The health born fetuses were set as control in the same period. Case-control and the three-level of monitor network of birth defects were used in the study in the participating 75 hospitals (Qingdao Women and Children's Medical Center, Affiliated Hospital of Medical College Qingdao University, Qingdao Municipal Hospital, etc.). The study and control group's parents were interviewed by an uniformed questionnaire which was designed specially with influence factors of birth defects. (1) There are 466 congenital malformational fetuses in the total of 77 231 fetuses collected in 75 hospitals. The congenital malformational rate accounts for about 6.034‰. The top six defect diseases were congenital heart disease (112 cases), total harelip (cleft lip; cleft lip with palate: 85 cases), polydactyly (53 cases), neural tube defects (38 cases), congenital hydrocephalus (37 cases) and limb reduction defect (27 cases) in turn, which amounts to 353 cases (54.48%, 353/648). (2) Their mother education level in the birth-defect group (25.6%) were significantly lower than that in control group (30.0%, P<0.05). (3) The rate of passive smoking, drinking, raising pets of the parents in birth-defect group were significantly higher than that in control group (P<0.05). (4) The rate of exposure to harmful chemical and physical factors of mothers in birth defects group (13.9% and 20.5%, respectively) was higher than that in control group (1.1% and 11.7%, respectively), the difference between which were significant (P<0.01). The rate of disease (34.3%), fever (13.1%), taking drugs (33.8%) in pregnancy period in birth defect group were higher than that in control group (13.5%, 1.5% and 9.9%, respectively), the difference between which were significant (P<0.01). The rate

Assessing validity of observational intervention studies - the Benchmarking Controlled Trials.

PubMed

Malmivaara, Antti

2016-09-01

Benchmarking Controlled Trial (BCT) is a concept which covers all observational studies aiming to assess impact of interventions or health care system features to patients and populations. To create and pilot test a checklist for appraising methodological validity of a BCT. The checklist was created by extracting the most essential elements from the comprehensive set of criteria in the previous paper on BCTs. Also checklists and scientific papers on observational studies and respective systematic reviews were utilized. Ten BCTs published in the Lancet and in the New England Journal of Medicine were used to assess feasibility of the created checklist. The appraised studies seem to have several methodological limitations, some of which could be avoided in planning, conducting and reporting phases of the studies. The checklist can be used for planning, conducting, reporting, reviewing, and critical reading of observational intervention studies. However, the piloted checklist should be validated in further studies. Key messages Benchmarking Controlled Trial (BCT) is a concept which covers all observational studies aiming to assess impact of interventions or health care system features to patients and populations. This paper presents a checklist for appraising methodological validity of BCTs and pilot-tests the checklist with ten BCTs published in leading medical journals. The appraised studies seem to have several methodological limitations, some of which could be avoided in planning, conducting and reporting phases of the studies. The checklist can be used for planning, conducting, reporting, reviewing, and critical reading of observational intervention studies.

Risk factors for essential thrombocythemia: A case-control study. Italian Leukemia Study Group.

PubMed

Mele, A; Visani, G; Pulsoni, A; Monarca, B; Castelli, G; Stazi, M A; Gentile, G; Mandelli, F

1996-05-15

Very little information is presently available regarding risk factors for essential thrombocythemia (ET). A case-control study was performed to study the possible association between ET and selected behavioral, occupational, and environmental exposures. Thirty-nine patients aged 20 years or older and 156 controls were enrolled in 2 Italian Hematology Departments located in Rome and Pavia. Controls were recruited among outpatients seen in the same hospitals and matched 4:1 to the patients after stratification by age and sex. Odds ratio (OR) estimates suggest an association between ET and hair dye use (in particular the use of dark hair dye for periods longer than 10 years: OR - 5.3; 95% confidence interval [CI], 1.4-19.9), living in houses built with tuff (a material with a high concentration of gamma-emitting radionuclides and radon) for longer than 9 years (OR = 5.1; 95% CI, 1.2-22.1), and selected occupations (electrical worker and shoemaker, OR +infinity and 2.7; 95% CI, 0.5-16 respectively). Behavioral exposures such as hair dyes, living in a tuff house, and working as an electrician are significantly associated with ET development. The data are consistent with those observed in acute leukemias.

Earth Observation Data Quality Monitoring and Control: A Case Study of STAR Central Data Repository

NASA Astrophysics Data System (ADS)

Han, W.; Jochum, M.

2017-12-01

Earth observation data quality is very important for researchers and decision makers involved in weather forecasting, severe weather warning, disaster and emergency response, environmental monitoring, etc. Monitoring and control earth observation data quality, especially accuracy, completeness, and timeliness, is very useful in data management and governance to optimize data flow, discover potential transmission issues, and better connect data providers and users. Taking a centralized near real-time satellite data repository, STAR (Center for Satellite Applications and Research of NOAA) Central Data Repository (SCDR), as an example, this paper describes how to develop new mechanism to verify data integrity, check data completeness, and monitor data latency in an operational data management system. Such quality monitoring and control of large volume satellite data help data providers and managers improve data transmission of near real-time satellite data, enhance its acquisition and management, and overcome performance and management issues to better serve research and development activities.

Pesticide Exposure and Head and Neck Cancers: A Case-Control Study in an Agricultural Region

PubMed Central

Amizadeh, Maryam; Safari-Kamalabadi, Mohammad; Askari-Saryazdi, Ghasem; Amizadeh, Marzieh; Reihani-Kermani, Hamed

2017-01-01

Introduction: Causes of head and neck cancers (HNCs) are multifactorial, and few studies have investigated the association between chemical exposure and HNCs. The objective of this study was to investigate associations between HNCs, agricultural occupations, and pesticide exposure. The potential for the accumulation of pesticides in the adipose tissue of patients was also investigated. Materials and Methods: A structured questionnaire was used to collect information on demographics, occupation, and exposure to pesticides in a hospital-based case-control study. Pesticide residue in the adipose tissue of the neck in both cases and controls was also monitored via gas chromatography–mass spectroscopy. Results: Thirty-one HNC cases were included in this study as well as 32 gender-, age-, and smoking-matched controls. An agricultural occupation was associated with HNC (odds ratio [OR], 3.26; 95% confidence interval [CI], 1.13–9.43) after controlling for age, sex, and smoking. Pesticide exposure was associated with total HNC cases (OR, 7.45; 95% CI, 1.78–3.07) and larynx cancer (OR, 9.33; 95% CI, 1.65–52.68). A dose-response pattern was observed for HNC cases (P=0.06) and larynx cancer (P=0.01). In tracing the pesticide residue, five chlorinated pesticides, namely dichlorodiphenyltrichloroethane (DDT), dichlorodipheny-ldichloroethane (DDD), dichlorodiphenyldichloroethylene (DDE), dieldrin, and lindane, were identified in the adipose tissue. Chlorinated pesticide detection was significantly associated with HNC (OR, 3.91; 95% CI 0.9–0.16.9). Conclusion: HNCs were found to be associated with pesticide exposure after controlling for confounders. A high education level was identified as a modifying factor decreasing the risk of HNCs. Further studies with larger number of subjects are recommended to assess these relationships in greater detail. PMID:28955675

Subclinical hypothyroidism is associated with migraine: A case-control study.

PubMed

Rubino, Elisa; Rainero, Innocenzo; Garino, Francesca; Vicentini, Costanza; Govone, Flora; Vacca, Alessandro; Gai, Annalisa; Gentile, Salvatore; Govone, Guido; Ragazzoni, Federico; Pinessi, Lorenzo; Giordana, Maria Teresa; Limone, Paolo

2018-01-01

Background Recent studies suggested a potential association between both overt and subclinical hypothyroidism and migraine. Aims of this study were to estimate the comorbidity of migraine in patients with subclinical hypothyroidism and to evaluate associated clinical characteristics. Methods Using a case-control strategy, 151 consecutive subclinical hypothyroidism patients (mean age 48.36 ± 15.86 years) and 150 controls (mean age 50.86 ± 9.19 years) were recruited. In all subjects, migraine characteristics were collected through a direct interview. Clinical and biochemical parameters (thyroid-stimulating hormone, free triiodothyronine, free thyroxine, and anti-thyroid antibodies) were compared between subclinical hypothyroidism patients in comorbidity with migraine and subclinical hypothyroidism patients without migraine. Results The prevalence of lifetime migraine was significantly higher in subclinical hypothyroidism patients in comparison with controls (46% vs. 13%, p < 0.001; OR 5.80; 95% CI = 3.35-10.34). Both migraine without and with aura were significantly higher in subclinical hypothyroidism patients than controls ( p < 0.001 and p = 0.010, respectively). Thyroid hormones and concentrations of antibodies did not differ between subclinical hypothyroidism patients with and without migraine. Interestingly, a comorbidity for autoimmune diseases was observed in subclinical hypothyroidism patients with migraine in respect to those without migraine ( p = 0.005). Conclusions Our data suggest that migraine is more frequent in patients with subclinical hypothyroidism in respect to controls. Further studies are needed in order to confirm this association.

Research participation experiences of informants of suicide and control cases: taken from a case-control psychological autopsy study of people who died by suicide.

PubMed

Wong, Paul W C; Chan, Wincy S C; Beh, Philip S L; Yau, Fiona W S; Yip, Paul S F; Hawton, Keith

2010-01-01

Ethical issues have been raised about using the psychological autopsy approach in the study of suicide. The impact on informants of control cases who participated in case-control psychological autopsy studies has not been investigated. (1) To investigate whether informants of suicide cases recruited by two approaches (coroners' court and public mortuaries) respond differently to the initial contact by the research team. (2) To explore the reactions, reasons for participation, and comments of both the informants of suicide and control cases to psychological autopsy interviews. (3) To investigate the impact of the interviews on informants of suicide cases about a month after the interviews. A self-report questionnaire was used for the informants of both suicide and control cases. Telephone follow-up interviews were conducted with the informants of suicide cases. The majority of the informants of suicide cases, regardless of the initial route of contact, as well as the control cases were positive about being approached to take part in the study. A minority of informants of suicide and control cases found the experience of talking about their family member to be more upsetting than expected. The telephone follow-up interviews showed that none of the informants of suicide cases reported being distressed by the psychological autopsy interviews. The acceptance rate for our original psychological autopsy study was modest. The findings of this study are useful for future participants and researchers in measuring the potential benefits and risks of participating in similar sensitive research. Psychological autopsy interviews may be utilized as an active engagement approach to reach out to the people bereaved by suicide, especially in places where the postvention work is underdeveloped.

Household-level risk factors for influenza among young children in Dhaka, Bangladesh: a case-control study.

PubMed

Doshi, Saumil; Silk, Benjamin J; Dutt, Dhiman; Ahmed, Moshtaq; Cohen, Adam L; Taylor, Thomas H; Brooks, W Abdullah; Goswami, Doli; Luby, Stephen P; Fry, Alicia M; Ram, Pavani K

2015-06-01

To identify household-level factors associated with influenza among young children in a crowded community in Dhaka, Bangladesh. We conducted a case-control study using existing active surveillance for respiratory illness. Cases were children aged 12-59 months with laboratory-confirmed influenza. Controls were children frequency-matched by age group with no respiratory illness in the prior 6 months. We interviewed caregivers and observed household handwashing behaviour. Soap consumption was estimated by summing weight differences of three bars of soap sequentially left in each household. We measured concentrations of airborne particulate matter <2.5 μg in diameter (PM2.5) in a subset of households. We used logistic regression to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI). We enrolled 145 cases and 341 controls between March 2009 and April 2010. Case and control household members were observed to wash hands with similar frequency during a 5-h period (mean, 0.64 events vs. 0.63, P = 0.87), and similar daily soap consumption per capita (mean 2.92 grams vs. 2.93, P = 0.92). Case households were more likely than controls to have crowded (≥4 persons) sleeping areas (aOR = 1.67, CI: 1.06-2.63) and cross-ventilated cooking spaces (aOR = 1.75, CI: 1.16-2.63). Case and control households had similar median 24-h geometric mean PM2.5 concentrations in the cooking (69.2 vs. 69.6 μg/m(3), P = 0.45) and sleeping (65.4 vs. 67.4 μg/m(3), P = 0.19) spaces. Handwashing with soap was practiced infrequently and was not associated with paediatric influenza in this community. Interventions aimed at crowded households may reduce influenza incidence in young children. © 2015 John Wiley & Sons Ltd.

HPV and cofactors for invasive cervical cancer in Morocco: a multicentre case-control study.

PubMed

Berraho, Mohamed; Amarti-Riffi, Afaf; El-Mzibri, Mohammed; Bezad, Rachid; Benjaafar, Noureddine; Benideer, Abdelatif; Matar, Noureddine; Qmichou, Zinab; Abda, Naima; Attaleb, Mohammed; Znati, Kaoutar; El Fatemi, Hind; Bendahhou, Karima; Obtel, Majdouline; Filali Adib, Abdelhai; Mathoulin-Pelissier, Simone; Nejjari, Chakib

2017-06-20

Limited national information is available in Morocco on the prevalence and distribution of HPV-sub-types of cervical cancer and the role of other risk factors. The aim was to determine the frequency of HPV-sub-types of cervical cancer in Morocco and investigate risk factors for this disease. Between November 2009 and April 2012 a multicentre case-control study was carried out. A total of 144 cases of cervical cancer and 288 age-matched controls were included. Odds-ratios and corresponding confidence-intervals were computed by conditional logistic regression models. Current HPV infection was detected in 92.5% of cases and 13.9% of controls. HPV16 was the most common type for both cases and controls. Very strong associations between HPV-sub-types and cervical cancer were observed: total-HPV (OR = 39), HPV16 (OR = 49), HPV18 (OR = 31), and multiple infections (OR = 13). Education, high parity, sexual intercourse during menstruation, history of sexually transmitted infections, and husband's multiple sexual partners were also significantly associated with cervical cancer in the multivariate analysis. Our results could be used to establish a primary prevention program and to prioritize limited screening to women who have specific characteristics that may put them at an increased risk of cervical cancer.

A Retrospective Case-Control Study, Factors Affecting Treatment Outcomes for Pulmonary Tuberculosis in İstanbul, Turkey

PubMed Central

Babalık, Aylin; Kılıçaslan, Zeki; Kızıltaş, Şule; Gencer, Serap; Öngen, Gül

2013-01-01

Background: Tuberculosis is a public health problem and its transmission is a threat to the community. Aims: The aim of this study was to determine the factors influencing the treatment outcomes and the effectiveness of the National Tuberculosis Program (NTP) in relation to the application of the directly observed treatment, short-course (DOTS) program in various sites in Istanbul, Turkey. Study Design: Case-Control Study Methods: A case-control study was used, where cases and controls were randomly selected from the Turkish Tuberculosis National Database, which includes complete data on treatment outcomes for patients recorded in the database from January 1, 2006 to December 31, 2009 and had one year follow-up. Results: The case group was composed of 464 patients with adverse outcome, while the control group was composed of 441 patients who had been cured of disease. Factors associated with adverse treatment outcome were >65 years of age (OR: 3.39 (1.99–5.76)) ; male gender (OR:2.11 (1.49–2.99)); born outside Turkey (OR: 5.48 (2.13–14.04)); co-morbidity (OR: 1.85 (1.29–2.65)); bilateral radiologic lesions (OR: 2.07 (1.41–3.00); previous treatment history (OR: 3.99 (2.78–5.74)); 3rd month positive microscopy (OR: 4.96 (3.04–8.09)) and any H&R +/− others multidrug resistant (MDR) resistance (OR: 22.64 (6.92–74.08)). There was no association between the adverse treatment outcome and the application site of direct observation treatment, short course (DOTS) delivery and the supervisors. Conclusion: Our findings indicate similar quality in DOTS application and supervision among patients with or without adverse treatment outcomes. However, patients with certain characteristics should be carefully monitored and aggressively treated. PMID:25207101

Tuberculosis stigma in Gezira State, Sudan: a case-control study.

PubMed

Ahmed Suleiman, M M; Sahal, N; Sodemann, M; El Sony, A; Aro, A R

2013-03-01

To evaluate the prevalence of tuberculosis (TB) stigma and to determine the relation between socio-demographic characteristics and TB stigma among TB cases and their controls in Gezira State, Sudan. A case-control study design was used. New smear-positive TB patients registered in Gezira State in 2010 (n = 425) and controls who attended the same health facility for other reasons (n < 850) formed the study population. Stigma was measured using a standard modified World Health Organization TB KAP (knowledge, attitudes, practice) instrument. TB stigma did not differ between TB cases and controls; mild stigma was found in both groups. The higher degree of stigma among both groups was significantly associated with higher age, lower level of education, residence in rural areas, unemployment and poor TB awareness, while sex had no association with the degree of stigma in either group. Although TB stigma among the Gezira population was found to be mild, it can affect treatment adherence. Empowering both TB patients and communities by increasing their knowledge through proper education programmes could effectively contribute to the effort of controlling TB in the state.

[Risk factors associated with non-alcoholic fatty liver disease: a case-control study].

PubMed

Caballería, Llorenç; Arteaga, Ingrid; Pera, Guillem; Rodríguez, Lluís; Alumà, Alba; Auladell, Maria Antònia; Torán, Pere

2013-09-21

To establish the factors associated with the presence of non-alcoholic fatty liver disease (NAFLD) and evaluate the influence of each component constituting the metabolic syndrome (MS) and the risk of developing NAFLD. We performed a multicenter, population-based, observational, analytical study of cases and controls. A case was defined as any patient fulfilling the inclusion criteria and presenting NAFLD by abdominal echography for any reason. A control was randomly selected for each case, from the same health center and of the same age and sex. All the cases underwent anamnesis, physical examination, complete biochemical analyses and determination of MS according to the National Cholesterol Education Program-Adult Treatment Panel III criteria. All the controls also underwent an abdominal echography. We included 327 cases and 377 controls with a mean age of 56 ± 12 years for the cases and of 55 ± 13 years for the controls (range: 17 and 80 years); 52.0% of the cases were males and 49.1% of males were controls. The risk factors associated with NAFLD were obesity (odds ratio [OR] 3.82, 95% confidence interval [95% CI] 2.19-6.66), MS (OR 1.73, 95% CI 1.09-2.75), insulin resistance (OR 3.65, 95% CI 2.18-6.12), and an increase in alanine aminotransferase (ALT) (OR 4.72, 95% CI 2.58-8.61) and gamma glutamyl transferase values (GGT) (OR 1.95, 95% CI 1.14-3.34). The components of the MS best predicting NAFLD were hyperglycemia (OR 1.65, 95% CI1.06-2.56) and triglyceride values (OR 1.75, 95% CI1.13-2.72). The independent variables associated with NAFLD were obesity, insulin resistance and elevated ALT and GGT. The components of MS best predicting NAFLD were hyperglycemia and an increase in triglyceride values. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Laryngospasm during emergency department ketamine sedation: a case-control study.

PubMed

Green, Steven M; Roback, Mark G; Krauss, Baruch

2010-11-01

The objective of this study was to assess predictors of emergency department (ED) ketamine-associated laryngospasm using case-control techniques. We performed a matched case-control analysis of a sample of 8282 ED ketamine sedations (including 22 occurrences of laryngospasm) assembled from 32 prior published series. We sequentially studied the association of each of 7 clinical variables with laryngospasm by assigning 4 controls to each case while matching for the remaining 6 variables. We then used univariate statistics and conditional logistic regression to analyze the matched sets. We found no statistical association of age, dose, oropharyngeal procedure, underlying physical illness, route, or coadministered anticholinergics with laryngospasm. Coadministered benzodiazepines showed a borderline association in the multivariate but not univariate analysis that was considered anomalous. This case-control analysis of the largest available sample of ED ketamine-associated laryngospasm did not demonstrate evidence of association with age, dose, or other clinical factors. Such laryngospasm seems to be idiosyncratic, and accordingly, clinicians administering ketamine must be prepared for its rapid identification and management. Given no evidence that they decrease the risk of laryngospasm, coadministered anticholinergics seem unnecessary.

A case-control study of diesel exhaust exposure and bladder cancer.

PubMed

Wynder, E L; Dieck, G S; Hall, N E; Lahti, H

1985-08-01

The relationship between bladder cancer and employment in occupations involving exposure to diesel exhaust was examined using data from a hospital-based case-control study of men aged 20 to 80 years in 18 hospitals in six U.S. cities, from January 1981 to May 1983. In this analysis, 194 cases and 582 controls were compared according to occupation, smoking history, alcohol and coffee consumption, and various demographic variables. No difference was found in the proportion of bladder cancer cases employed in occupations with exposure to diesel exhaust compared to controls. This relationship did not change after taking smoking habits into account. Bladder cancer cases were significantly more likely to be current smokers of cigarettes than were controls.

A general regression framework for a secondary outcome in case-control studies.

PubMed

Tchetgen Tchetgen, Eric J

2014-01-01

Modern case-control studies typically involve the collection of data on a large number of outcomes, often at considerable logistical and monetary expense. These data are of potentially great value to subsequent researchers, who, although not necessarily concerned with the disease that defined the case series in the original study, may want to use the available information for a regression analysis involving a secondary outcome. Because cases and controls are selected with unequal probability, regression analysis involving a secondary outcome generally must acknowledge the sampling design. In this paper, the author presents a new framework for the analysis of secondary outcomes in case-control studies. The approach is based on a careful re-parameterization of the conditional model for the secondary outcome given the case-control outcome and regression covariates, in terms of (a) the population regression of interest of the secondary outcome given covariates and (b) the population regression of the case-control outcome on covariates. The error distribution for the secondary outcome given covariates and case-control status is otherwise unrestricted. For a continuous outcome, the approach sometimes reduces to extending model (a) by including a residual of (b) as a covariate. However, the framework is general in the sense that models (a) and (b) can take any functional form, and the methodology allows for an identity, log or logit link function for model (a).

Colorectal cancer and its association with the metabolic syndrome: a Malaysian multi-centric case-control study.

PubMed

Ulaganathan, V; Kandiah, M; Zalilah, M S; Faizal, J A; Fijeraid, H; Normayah, K; Gooi, B H; Othman, R

2012-01-01

Colorectal cancer (CRC) and the metabolic syndrome (MetS) are both on the rise in Malaysia. A multi-centric case-control study was conducted from December 2009 to January 2011 to determine any relationship between the two. Patients with confirmed CRC based on colonoscopy findings and cancer free controls from five local hospitals were assessed for MetS according to the International Diabetes Federation (IDF) definition. Each index case was matched for age, gender and ethnicity with two controls (140: 280). MetS among cases was highly prevalent (70.7%), especially among women (68.7%). MetS as an entity increased CRC risk by almost three fold independently (OR=2.61, 95%CI=1.53-4.47). In men MetS increased the risk of CRC by two fold (OR=2.01, 95%CI, 1.43-4.56), demonstrating an increasing trend in risk with the number of Mets components observed. This study provides evidence for a positive association between the metabolic syndrome and colorectal cancer. A prospective study on the Malaysian population is a high priority to confirm these findings.

Occupation and leukemia: a population-based case-control study in Iowa and Minnesota.

PubMed

Blair, A; Zheng, T; Linos, A; Stewart, P A; Zhang, Y W; Cantor, K P

2001-07-01

Studies have suggested that risk of leukemia may be associated with occupational or industrial exposures and risk may vary by the histological type of the disease. A population-based case-control study was conducted in Iowa and Minnesota to evaluate the association between various occupations, industries, and occupational exposures and leukemia risk. A total of 513 cases and 1,087 controls was included in the study. A lifetime occupational history and other risk factor information were collected through in-person interviews, and a job-exposure matrix was used to assess possible risks associated with specific exposures. A significantly increased risk of leukemia was observed among agricultural service industries and among nursing and healthcare workers. Janitors, cleaners, and light truck drivers also experienced increased risk. Those employed in plumbing, heating and air conditioning industries, and sales of nondurable goods (such as paints and varnishes) had an increased risk. Printers, painters, and workers in the food and metal industries had a nonsignificantly increased risk of leukemia. Analyses by specific exposures and histology of leukemia showed that risk of leukemia associated with occupational or industrial exposures may vary by histological type of the disease. An increased risk of leukemia among workers employed in agricultural industries, nursing and healthcare workers, and in a few occupations with possible exposure to solvents is consistent with earlier studies. Associations of risk with occupations not observed previously deserve further assessment. Published 2001 Wiley-Liss, Inc.

Head or brain injuries and Alzheimer's disease: A nested case-control register study.

PubMed

Tolppanen, Anna-Maija; Taipale, Heidi; Hartikainen, Sirpa

2017-12-01

Many previous studies have been limited by self- or proxy-reported injury or short follow-up. We investigated whether head or brain injuries are associated with Alzheimer's disease (AD), possible modifying factors and dose-response relationship. Nested register-based case-control study of all community dwellers who received clinically verified AD diagnosis in Finland in 2005 to 2011 (n = 70,719) and one to four matched controls for each case (n of controls = 282,862). The magnitude of association between hospital-treated head and/or brain injuries was strongly dependent on the lag time between exposure and outcome. With a 5-year lag time, head injury (adjusted odds ratio; 95% confidence interval 1.19; 1.15-1.23) or brain injury (1.23; 1.18-1.29) was associated with higher risk of AD. Dose-response relationship with number and severity of injuries was observed. Associations were stronger in those with earlier onset of AD. Stronger associations with shorter lag times indicate that head and/or brain injuries may also reflect the ongoing AD disease process. Copyright © 2017 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

Analgesics use and ESRD in younger age: a case-control study

PubMed Central

van der Woude, Fokke J; Heinemann, Lothar AJ; Graf, Helmut; Lewis, Michael; Moehner, Sabine; Assmann, Anita; Kühl-Habich, Doerthe

2007-01-01

Background An ad hoc peer-review committee was jointly appointed by Drug Authorities and Industry in Germany, Austria and Switzerland in 1999/2000 to review the evidence for a causal relation between phenacetin-free analgesics and nephropathy. The committee found the evidence as inconclusive and requested a new case-control study of adequate design. Methods We performed a population-based case-control study with incident cases of end-stage renal disease (ESRD) under the age of 50 years and four age and sex-matched neighborhood controls in 170 dialysis centers (153 in Germany, and 17 in Austria) from January 1, 2001 to December 31, 2004. Data on lifetime medical history, risk factors, treatment, job exposure and intake of analgesics were obtained in a standardized face-to-face interview using memory aids to enhance accuracy. Study design, study performance, analysis plan, and study report were approved by an independent international advisory committee and by the Drug Authorities involved. Unconditional logistic regression analyses were performed. Results The analysis included 907 cases and 3,622 controls who had never used phenacetin-containing analgesics in their lifetime. The use of high cumulative lifetime dose (3rd tertile) of analgesics in the period up to five years before dialysis was not associated with later ESRD. Adjusted odds ratios with 95% confidence intervals were 0.8 (0.7 – 1.0) and 1.0 (0.8 – 1.3) for ever- compared with no or low use and high use compared with low use, respectively. The same results were found for all analgesics and for mono-, and combination preparations with and without caffeine. No increased risk was shown in analyses stratifying for dose and duration. Dose-response analyses showed that analgesic use was not associated with an increased risk for ESRD up to 3.5 kg cumulative lifetime dose (98 % of the cases with ESRD). While the large subgroup of users with a lifetime dose up to 0.5 kg (278 cases and 1365 controls) showed a

Obstacles to action in arthritis: a community case-control study.

PubMed

Hutton, Ingrid; Gamble, Greg; McLean, Grant; Butcher, Hugh; Gow, Peter; Dalbeth, Nicola

2009-07-01

Despite the benefits of physical activity, people with arthritis are less active than the general population. The aim of this study was to determine the motivators and obstacles to physical activity for adults with arthritis. Participants were identified from the Obstacles to Action Study, a community based study of 8163 adults, which explored barriers and motivators to physical activity. A 1:1 case-control study was designed; cases were identified as those participants who reported arthritis (n = 1106). Each case was matched with an age, sex and ethnicity-matched non-arthritis control (n = 1106). Cases were less likely to achieve recommended physical activity targets (58.8% vs. 68.1% P = 0.00001). Furthermore, fewer people with arthritis believed that physical activity would help them lead healthy lives (86.7% vs. 91.3% P = 0.006) or viewed physical activity as a priority (53.8% vs. 59.8% P = 0.005). Cases were less confident in their abilities to try a new activity (37.1% vs. 43.7% P = 0.002) or maintain a healthy weight (65.0% vs. 74.3% P = 0.00001). Cases also reported greater negative impact scores for barriers to activity, particularly arthritis, accessibility, cost and discomfort while exercising. Motivators and environmental barriers to activity were similar for cases and controls. These findings persisted after adjusting for educational level, body mass index and comorbidities. People with arthritis are less active and demonstrate different attitudes toward physical activity. Although people with arthritis identify similar environmental barriers, they have different psychosocial barriers. In order to design effective physical activity programs for people with arthritis, these barriers must be specifically addressed.

Research Methods in Healthcare Epidemiology and Antimicrobial Stewardship-Observational Studies.

PubMed

Snyder, Graham M; Young, Heather; Varman, Meera; Milstone, Aaron M; Harris, Anthony D; Munoz-Price, Silvia

2016-10-01

Observational studies compare outcomes among subjects with and without an exposure of interest, without intervention from study investigators. Observational studies can be designed as a prospective or retrospective cohort study or as a case-control study. In healthcare epidemiology, these observational studies often take advantage of existing healthcare databases, making them more cost-effective than clinical trials and allowing analyses of rare outcomes. This paper addresses the importance of selecting a well-defined study population, highlights key considerations for study design, and offers potential solutions including biostatistical tools that are applicable to observational study designs. Infect Control Hosp Epidemiol 2016;1-6.

Common mental disorders associated with tuberculosis: a matched case-control study.

PubMed

de Araújo, Gleide Santos; Pereira, Susan Martins; dos Santos, Darci Neves; Marinho, Jamocyr Moura; Rodrigues, Laura Cunha; Barreto, Mauricio Lima

2014-01-01

Despite the availability of treatment and a vaccine, tuberculosis continues to be a public health problem worldwide. Mental disorders might contribute to the burden of the disease. The objective of this study was to investigate the association between common mental disorders and tuberculosis. A matched case-control study was conducted. The study population included symptomatic respiratory patients who attended three referral hospitals and six community clinics in the city of Salvador, Brazil. A doctor's diagnosis defined potential cases and controls. Cases were newly diagnosed tuberculosis cases, and controls were symptomatic respiratory patients for whom tuberculosis was excluded as a diagnosis by the attending physician. Cases and controls were ascertained in the same clinic. Data collection occurred between August 2008 and April 2010. The study instruments included a structured interview, a self-reporting questionnaire for the identification of common mental disorders, and a questionnaire for alcoholism. An univariate analysis included descriptive procedures (with chi-square statistics), and a multivariate analysis used conditional logistic regression. The mean age of the cases was 38 years, and 61% of the cases were males. After adjusting for potential confounders, the odds of tuberculosis were significantly higher in patients diagnosed with a common mental disorder (OR: 1.34; 95% CI 1.05-1.70). There appears to be a positive and independent association between common mental disorders and tuberculosis; further epidemiological studies are required to increase our understanding of the possible biological and social mechanisms responsible for this association. Independent of the direction of the association, this finding has implications for the provision of care for mental disorders and for tuberculosis.

High Spicy Food Intake and Risk of Cancer: A Meta-analysis of Case-control Studies.

PubMed

Chen, Yu-Heng; Zou, Xiao-Nong; Zheng, Tong-Zhang; Zhou, Qi; Qiu, Hui; Chen, Yuan-Li; He, Mei; Du, Jia; Lei, Hai-Ke; Zhao, Ping

2017-09-20

Studies on the association between spicy food intake and cancer risk have reported inconsistent results. We quantitatively assessed this association by conducting a meta-analysis based on evidence from case-control studies. PubMed, EMBASE, and the Cochrane Library were searched for eligible publications. Combined odds ratios (OR s) with their 95% confidence interval (CI) were calculated using a random- or fixed-effects model. The methodological quality of the included articles was assessed using the Newcastle-Ottawa scale (NOS). All data were analyzed using STATA 11.0 software (version 11.0; StataCorp., College Station, TX, USA). Subgroup analyses were also performed with stratification by region, sex, number of cases, cancer subtype, source of the control group, and NOS score. A total 39 studies from 28 articles fulfilled the inclusion criteria for the meta-analysis (7884 patients with cancer and 10,142 controls). Comparison of the highest versus lowest exposure category in each study revealed a significant OR of 1.76 (95% CI = 1.35-2.29) in spite of significant heterogeneity (P < 0.001). In the subgroup analyses, this positive correlation was still found for gastric cancer, different regions, different numbers of cases, different sources of the control group, and high-quality articles (NOS score of ≥ 7). However, no statistically significant association was observed for women, esophageal cancer, gallbladder cancer, or low-quality articles (NOS score of <7). No evidence of publication bias was found. Evidence from case-control studies suggested that a higher level of spicy food intake may be associated with an increased incidence of cancer despite significant heterogeneity. More studies are warranted to clarify our understanding of the association between high spicy food intake and the risk of cancer.

Vitamin E Intake and Risk of Renal Cell Carcinoma: A Meta-Analysis of 7 Case-Control Studies.

PubMed

Shang, Yonggang; Yi, Shanhong; Cui, Dong; Han, Guangwei; Liu, Chengcheng

2015-07-01

Vitamin E intake may reduce the risk of renal cell carcinoma, but the results were inconsistent. Hence, we conducted a meta-analysis to assess the association between dietary vitamin E intake and the risk of renal cell carcinoma. We searched PubMed to identify the relevant case-control studies up to June 2014. Reference lists of retrieved articles were also reviewed. Odds ratios and corresponding 95% confidence intervals were used to estimate the association between dietary vitamin E intake and the risk of renal cell carcinoma. We identified 7 case-control studies regarding dietary vitamin E intake and risk of renal cell carcinoma, involving 5789 cases and 14866 controls. The odds ratio of renal cell carcinoma for the highest compared with the lowest dietary vitamin E intake was 0.75 (95% confidence interval: 0.59-0.91), and heterogeneity was observed across studies. The association between dietary vitamin E intake and the risk of renal cell carcinoma was not significantly differed by gender, but this association were inconsistent in the North American and European populations. Our study provided a evidence that there was a significant inverse association of dietary vitamin E intake with risk of renal cell carcinoma. However, this finding was based on the case-control studies, more well-designed cohort studies are needed. Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Effects of environmental factors on child survival in Bangladesh: a case control study.

PubMed

Hoque, B A; Chakraborty, J; Chowdhury, J T; Chowdhury, U K; Ali, M; el Arifeen, S; Sack, R B

1999-03-01

The need for further studies on relationships between deaths and environmental variables has been reported in the literature. This case-control study was, therefore, carried out to find out the associations between several social and environmental variables and deaths of children due to infectious diseases such as those leading to diarrhoea, acute respiratory infection, measles and other diseases. Six hundred and twenty-five deaths (cases) and an equal number of matched living children (controls) aged 1-59 months, were studied in rural Matlab. An analysis of crude and adjusted odds ratio showed differential associations. Sources of drinking water, amount of stored water, conditions of latrines, number of persons sleeping with the child and the type of cooking site were statistically significantly associated with deaths due to infectious diseases after controlling for breast feeding, immunization, and the family size. Significant associations were also observed between: (i) the sources of drinking water and deaths due to ARI, and (ii) conditions of latrines and deaths due to diarrhoeal diseases, after controlling for the confounding variables. Several other environmental factors also showed associations with these various death groups, but they were not statistically significant. The size of the samples in death groups (small) and the prevalence of more or less homogeneous environmental health conditions probably diminished the magnitude of the effects. The results of the study reconfirm the importance of environmental health intervention in child survival, irrespective of breast-feeding, immunization, and selected social variables.

Glioma and occupational exposure in Sweden, a case-control study.

PubMed Central

Rodvall, Y; Ahlbom, A; Spännare, B; Nise, G

1996-01-01

OBJECTIVES: The aim of the study was to analyse whether any job titles, industrial codes, and certain occupational exposures were associated with an increased risk of glioma. METHODS: A population based case-control study of incident primary brain tumours in adults was carried out in Uppsala, Sweden in the period 1987-90. The study included 192 cases of glioma and 192 matched controls. It also included cases with other tumours of the central nervous system with matched controls. Information from all 343 controls was used in this study. Information was collected by means of a questionnaire that was sent to all subjects. An occupational hygienist reviewed the questionnaires for self reported exposures to substances and assessed whether these reported exposures were plausible or not in the corresponding occupation. RESULTS: The kappa coefficient for those classified by the two methods ranged between 0.46 and 0.88, and they were almost the same for cases and controls. For men exposed to solvents a relative risk (RR) of 2.6 (95% CI 1.3 to 5.2) was found. For men exposed to pesticides the RR was 1.8 (95% CI 0.6 to 5.1), and for plastic materials the RR was 3.6 (95% CI 1.0 to 12.4). For men employed in forestry and logging the RR was 2.2 (95% CI 0.9 to 5.3) and in basic metal industries 2.0 (95% CI 1.0 to 4.0). CONCLUSION: An increased risk of glioma was associated with use of solvents, pesticides, and plastic materials but this should be interpreted with some caution. PMID:8983463

Response rates in case-control studies of cancer by era of fieldwork and by characteristics of study design.

PubMed

Xu, Mengting; Richardson, Lesley; Campbell, Sally; Pintos, Javier; Siemiatycki, Jack

2018-04-09

The purpose of this study was to describe time trends in response rates in case-control studies of cancer and identify study design factors that influence response rate. We reviewed 370 case-control studies of cancer published in 12 journals during indicator years in each of the last four decades. We estimated time trends of response rates and reasons for nonresponse in each of the following types of study subjects: cases, medical source controls, and population controls. We also estimated response rates according to characteristics of study context. Median response rates among cases and population controls were between 75% and 80% in the 1970s. Between 1971 and 2010, study response rates declined by 0.31% per year for cases and 0.78% for population controls. Only a minority of studies reported reasons for nonparticipation; subject refusal was the most common reported reason. Studies conducted in North America had lower median response rates than studies conducted in Europe. In-person and telephone interviews elicited higher response rates than mail questionnaires. Response rates from case-control studies of cancer have declined, and this could threaten the validity of results derived from these studies. Copyright © 2018 Elsevier Inc. All rights reserved.

Violence against Women and Gastroschisis: A Case-Control Study

PubMed Central

Ortega-García, Juan Antonio; Soldin, Offie P.; Sánchez-Sauco, Miguel Felipe; Cánovas-Conesa, Alicia; Gomaríz-Peñalver, Virtudes; Jaimes-Vega, Diana Carolina; Perales, Joseph E.; Cárceles-Alvarez, Alberto; Martínez-Ros, Maria Teresa; Ruiz, Daniel

2013-01-01

Background: Gastroschisis, a birth defect characterized by herniated fetal abdominal wall, occurs more commonly in infants born to teenage and young mothers. Ischemia of the vascular vitelline vessels is the likely mechanism of pathogenesis. Given that chronic stress and violence against women are risk factors for cardiovascular disease we explored whether these may represent risk factors for gastroschisis, when they occur during pregnancy. A case-control study was conducted, with 15 incident cases of children born with gastroschisis in the Region of Murcia, Spain, from December 2007 to June 2013. Forty concurrent controls were recruited at gestation weeks 20–24 or post-partum. All mothers of cases and controls completed a comprehensive, in-person, ‘green sheet’ questionnaire on environmental exposures. Results: Mothers of children with gastroschisis were younger, smoked more cigarettes per week relative to controls, were exposed to higher amounts of illegal drugs, and suffered from domestic violence more frequently than the controls. Multivariable logistic regression analysis highlights periconceptional ‘gender-related violence’ (OR: 16.6, 95% CI 2.7 to 101.7) and younger maternal age (OR 1.1, 95% CI 1.0–1.3). Conclusions: Violence against pregnant women is associated with birth defects, and should be studied in more depth as a cause-effect teratogenic. Psychosocial risk factors, including gender-based violence, are important for insuring the health and safety of the pregnant mother and the fetus. PMID:24142184

Sample size calculations for case-control studies

Cancer.gov

This R package can be used to calculate the required samples size for unconditional multivariate analyses of unmatched case-control studies. The sample sizes are for a scalar exposure effect, such as binary, ordinal or continuous exposures. The sample sizes can also be computed for scalar interaction effects. The analyses account for the effects of potential confounder variables that are also included in the multivariate logistic model.

Drug and alcohol crash risk : a case-control study.

DOT National Transportation Integrated Search

2016-12-01

This study used a case-control design to estimate the risk of crashes involving drivers using drugs, alcohol or both. Data was collected in Virginia Beach, Virginia, for 20 months. The study obtained biological measures on more than 3,000 crash...

Postnatal risk factors for testicular cancer: The EPSAM case-control study.

PubMed

Moirano, Giovenale; Zugna, Daniela; Grasso, Chiara; Mirabelli, Dario; Lista, Patrizia; Ciuffreda, Libero; Segnan, Nereo; Merletti, Franco; Richiardi, Lorenzo

2017-11-01

Testicular cancer is considered to originate from an impaired differentiation of fetal germ cells, but puberty could represent another time window of susceptibility. Our study aimed at investigating the association between environmental exposures acting during puberty/adolescence (13-19 years of age) and the risk of testicular cancer. We used data of the EPSAM study, a case-control study on germ-cell testicular cancer conducted in the province of Turin, Italy, involving cases diagnosed between 1997 and 2008. Histologically confirmed cases (n = 255) and controls (n = 459) completed a postal questionnaire focusing in particular on the pubertal period (namely age 13 years) with questions on physical activity (competitive sports, gardening), lifestyle (alcohol consumption, smoking), occupational history and medical conditions. All analyses were adjusted for the matching variables, cryptorchidism and educational level. Having done at least one competitive sport during puberty (odds ratio [OR]: 0.72, 95% confidence interval: 0.52-1.00), gardening activities during puberty (OR: 0.62, 0.42-0.94) and having a lower weight than peers during puberty (OR: 0.64, 0.42-0.97) were all inversely associated with the risk of testicular cancer. No evidence of association between smoking or alcohol consumption during puberty and the risk of testicular cancer was observed. Regarding agriculture-related occupations, we found an association with the risk of testicular cancer both for occasional jobs during puberty (OR: 2.40, 95% CI: 1.08-5.29) and ever employment in adolescence (OR: 2.59, 95% CI: 0.83-8.10). Our results suggest that postnatal exposures could play a role in testicular cancer aetiology, at least when acting in puberty or adolescence. © 2017 UICC.

Risk factors for gallbladder cancer: a case-control study.

PubMed

Jain, Kajal; Sreenivas, V; Velpandian, T; Kapil, Umesh; Garg, Pramod Kumar

2013-04-01

Risk factors for gallbladder cancer (GBC) except gallstones are not well known. The objective was to study the risk factors for GBC. In a case-control study, 200 patients with GBC, 200 healthy controls and 200 gallstones patients as diseased controls were included prospectively. The risk factors studied were related to socioeconomic profile, life style, reproduction, diet and bile acids. On comparing GBC patients (mean age 51.7 years; 130 females) with healthy controls, risk factors were chemical exposure [odd ratios (OR): 7.0 (2.7-18.2); p < 0.001)], family history of gallstones [OR: 5.3 (1.5-18.9); p < 0.01)], tobacco [OR: 4.1 (1.8-9.7); p < 0.001)], fried foods [OR: 3.1 (1.7-5.6); p < 0.001], joint family [OR: 3.2 (1.7-6.2); p < 0.001], long interval between meals [OR: 1.4 (1.2-1.6); p < 0.001] and residence in Gangetic belt [OR: 3.3 (1.8-6.2); p < 0.001]. On comparing GBC cases with gallstone controls, risk factors were female gender [OR: 2.4 (1.3-4.3); p = 0.004], residence in Gangetic belt [OR: 2.3 (1.2-4.4); p = 0.012], fried foods [OR: 2.5 (1.4-4.4); p < 0.001], diabetes [OR: 2.7 (1.2-6.4); p = 0.02)], tobacco [OR 3.8 (1.7-8.1); p < 0.001)] and joint family [OR: 2.1 (1.2-3.4); p = 0.004]. The ratio of secondary to primary bile acids was significantly higher in GBC cases than gallstone controls (20.8 vs. 0.44). Fried foods, tobacco, chemical exposure, family history of gallstones, residence in Gangetic belt and secondary bile acids were significant risk factors for GBC. Copyright © 2012 UICC.

Herpesviruses in etiopathogenesis of aggressive periodontitis: A meta-analysis based on case-control studies.

PubMed

Li, Fei; Zhu, Ce; Deng, Feng-Ying; Wong, May Chun Mei; Lu, Hai-Xia; Feng, Xi-Ping

2017-01-01

Previous studies have found that herpesviruses are associated with aggressive periodontitis (AgP). However, these findings are controversial. This meta-analysis was aimed at clarifying the association between herpesviruses and AgP. We identified eligible case-control studies evaluating the association between herpesviruses and AgP from PubMed and Embase databases in October 2015. Original data were extracted and quality assessment was done. Overall odds ratios (ORs) and 95% confidence intervals (CIs) were estimated. Random-effects model was determined. The stability was evaluated by sensitivity analysis. Finally, Egger's funnel plot was used to investigate the publication bias. Twelve case-control studies involving 322 patients and 342 controls were included in the present meta-analysis. The included case-control studies were assessed as high quality. The quantitative synthesis results for Epstein-Barr virus (EBV) showed significance (10 studies: p = 0.0008, OR = 6.11, 95% CI = 2.13-17.51); nevertheless, evidence of publication bias for EBV was considerable (EBV: Egger's test, p<0.001). Human cytomegalovirus (HCMV) and Herpes simplex virus type 1 (HSV-1) had significant association with AgP (12 studies for HCMV: p = 0.009, OR = 3.63, 95% CI = 2.15-6.13; 4 studies for HSV-1: p<0.001, OR = 19.19, 95% CI = 4.16-79.06). Sensitivity analyses showed the results yielded consistency, and no significant publication bias was observed for HCMV. The association between Herpes simplex virus type 2 (HSV-2) and AgP was inconclusive (2 studies: p = 0.20, OR = 3.46, 95% CI = 0.51-23.51). This meta-analysis suggests that HCMV and HSV-1 are significantly associated with AgP. However, due to the heterogeneity among studies these conclusions should be cautiously interpreted. There is insufficient evidence to draw any conclusion between EBV, HSV-2 and AgP based on the currently limited data.

Case-Control Studies of Sporadic Enteric Infections: A Review and Discussion of Studies Conducted Internationally from 1990 to 2009

PubMed Central

Fullerton, Kathleen E.; Scallan, Elaine; Kirk, Martyn D.; Mahon, Barbara E.; Angulo, Frederick J.; de Valk, Henriette; van Pelt, Wilfrid; Gauci, Charmaine; Hauri, Anja M.; Majowicz, Shannon; O’Brien, Sarah J.

2015-01-01

Epidemiologists have used case-control studies to investigate enteric disease outbreaks for many decades. Increasingly, case-control studies are also used to investigate risk factors for sporadic (not outbreak-associated) disease. While the same basic approach is used, there are important differences between outbreak and sporadic disease settings that need to be considered in the design and implementation of the case-control study for sporadic disease. Through the International Collaboration on Enteric Disease “Burden of Illness” Studies (the International Collaboration), we reviewed 79 case-control studies of sporadic enteric infections caused by nine pathogens that were conducted in 22 countries and published from 1990 through to 2009. We highlight important methodological and study design issues (including case definition, control selection, and exposure assessment) and discuss how approaches to the study of sporadic enteric disease have changed over the last 20 years (e.g., making use of more sensitive case definitions, databases of controls, and computer-assisted interviewing). As our understanding of sporadic enteric infections grows, methods and topics for case-control studies are expected to continue to evolve; for example, advances in understanding of the role of immunity can be used to improve control selection, the apparent protective effects of certain foods can be further explored, and case-control studies can be used to provide population-based measures of the burden of disease. PMID:22443481

Association between biomass fuel and pulmonary tuberculosis: a nested case-control study.

PubMed

Kolappan, C; Subramani, R

2009-08-01

To quantify the association between biomass fuel usage and sputum-positive pulmonary tuberculosis. A tuberculosis prevalence survey was conducted in a random sample of 50 rural units (villages) and three urban units in the Tiruvallur district of Tamilnadu, India during the period 2001-2003. Additional data regarding exposure to tobacco smoking, alcohol consumption, biomass fuel usage and Standard of Living Index (SLI) were also collected from the study participants. A nested case-control study was carried out in this population. Cases are defined as bacteriological-positive cases diagnosed by either sputum smear or culture examination. For each case, five age- (within +/-5 years of age) and sex-matched controls were selected randomly from the non-cases residing in the same village/unit. Thus, 255 cases and 1275 controls were included in this study. The unadjusted OR measured from univariate analysis for biomass fuel is 2.9 (95% CI 1.8 to 4.7). The adjusted OR measured from multivariate analysis using Cox regression is 1.7 (95% CI 1.0 to 2.9). Thirty-six percent of cases are attributable to biomass fuel usage. The findings from this case-control study add to the evidence for an independent association between biomass smoke and pulmonary tuberculosis. Improvement in standards of living brought about by economic development will lead to more people using cleaner fuels for cooking than biomass fuel which in turn will lead to a reduction in the occurrence of pulmonary tuberculosis in the community.

Clinical and psychological features of normal-weight women with subthreshold anorexia nervosa: a pilot case-control observational study.

PubMed

Tagliabue, Anna; Ferraris, Cinzia; Martinelli, Valentina; Pinelli, Giovanna; Repossi, Ilaria; Trentani, Claudia

2012-01-01

Weight preoccupations have been frequently reported in normal-weight subjects. Subthreshold anorexia nervosa (s-AN, all DSM IV TR criteria except amenorrhea or underweight) is a form of eating disorder not otherwise specified that has received scarce scientific attention. Under a case-control design we compared the general characteristics, body composition, and psychopathological features of normal-weight patients with s-AN with those of BMI- and sex-matched controls. Participants in this pilot study included 9 normal-weight women who met the DSM IV TR criteria for s-AN and 18 BMI-matched normal-weight controls. The general characteristics of the study participants were collected by questionnaire. Body composition was measured by bioelectrical impedance. Behavioral and psychological measures included the standardized symptom checklist (SCL-90-R) and the eating disorder inventory (EDI-2). There were no differences in age, education, employment status, marital status, and history of previous slimming treatment in the two study groups. In addition, anthropometric measures and body composition of s-AN patients and BMI-matched normal weight controls were not significantly different. In the s-AN subgroup, we found a significant relationship between waist circumference and the SCL-90-R obsessivity-compulsivity scale (n=9, r=-0.69, p<0.05). After multiple regression analysis, the SCL-90-R obsessivity-compulsivity scale (beta = 0.61, t=2.7, p=0.017) was the only independent predictor of the presence s-AN in our study cohort. These pilot results suggest that psychopathological criteria (particularly related to the obsessivity-compulsivity dimension) may be more useful than anthropometric measures for screening of s-AN in normal-weight women.

A modified case-control study of cryptosporidiosis (using non-Cryptosporidium-infected enteric cases as controls) in a community setting.

PubMed

Pintar, K D M; Pollari, F; Waltner-Toews, D; Charron, D F; McEwen, S A; Fazil, A; Nesbitt, A

2009-12-01

Data from the first sentinel site (Waterloo Region, Ontario) of the Canadian Integrated Enteric Disease Surveillance System (C-EnterNet) were used in a secondary-based case-control study of laboratory-confirmed Cryptosporidium infections to study the role of various exposure factors. The incidence of cryptosporidiosis in Waterloo Region was almost double both the provincial and national rates. Persons ill with one of nine other enteric infections (amoebiasis, campylobacteriosis, cyclosporiasis, giardiasis, listeriosis, salmonellosis, shigellosis, verotoxigenic E. coli infections, yersiniosis) captured by the surveillance system were used as the control group. Of 1204 cases of enteric illness in the sentinel area between April 2005 and December 2007, 36 cases and 803 controls were selected after excluding outbreak and international travel-related cases. Univariable analyses (Pearson chi2 and Fisher's exact tests) and multivariable logistic regression were performed. Results of the multivariable analysis found that cryptosporidiosis was associated with swimming in a lake or river (OR 2.9, 95% CI 1.2-7.4), drinking municipal water (a potential surrogate for urban respondents vs. rural) (OR 2.4, 95% CI 1.04-5.7), and having a family member with a diarrhoeal illness (OR 2.9, 95% CI 1.3-6.4).

Brain-relevant antibodies in first-episode psychosis: a matched case-control study.

PubMed

Gaughran, Fiona; Lally, John; Beck, Katherine; McCormack, Ruaidhri; Gardner-Sood, Poonam; Coutinho, Ester; Jacobson, Leslie; Lang, Bethan; Sainz-Fuertes, Ricardo; Papanastasiou, Evangelos; Di Forti, Marta; Nicholson, Tim; Vincent, Angela; Murray, Robin M

2018-06-01

There has been much recent excitement about the possibility that some cases of psychosis may be wholly due to brain-reactive antibodies, with antibodies to N-methyl-D-aspartate receptor (NMDAR) and the voltage-gated potassium channel (VGKC)-complex reported in a few patients with first-episode psychosis (FEP). Participants were recruited from psychiatric services in South London, UK, from 2009 to 2011 as part of the Genetics and Psychosis study. We conducted a case-control study to examine NMDAR and VGKC-complex antibody levels and rates of antibody positivity in 96 patients presenting with FEP and 98 controls matched for age and sex. Leucine-rich glioma inactiviated-1 (LGI1) and contactin-associated protein (CASPR) antibodies were also measured. Notably, patients with suspicion of organic disease were excluded. VGKC-complex antibodies were found in both cases (n = 3) and controls (n = 2). NMDAR antibody positivity was seen in one case and one control. Either LGI1-Abs or CASPR2-Abs were found in three cases and three controls. Neuronal antibody staining, consistent with the above results or indicating potential novel antigens, was overall positive in four patients but also in six controls. Overall, antibody positivity was at low levels only and not higher in cases than in controls. This case-control study of the prevalence of antibodies in FEP does not provide evidence to support the hypothesis that FEP is associated with an immune-mediated process in a subgroup of patients. Nevertheless, as other bio-clinical factors may influence the effect of such antibodies in a given individual, and patients with organic neurological disease may be misdiagnosed as FEP, the field requires more research to put these findings in context.

[Voice disorders related to job stress in teaching: a case-control study].

PubMed

Giannini, Susana Pimentel Pinto; Latorre, Maria do Rosário Dias de Oliveira; Ferreira, Leslie Piccolotto

2012-11-01

This case-control study aimed to test the association between voice disorders and job stress among public schoolteachers in São Paulo, Brazil. The groups consisted of teachers with (n = 165) and without (n = 105) voice-related complaints. Both groups answered the questionnaires Conditions of Vocal Production and Job Stress Scale. Analysis of cases and controls showed comparable samples, differing only by vocal symptoms. There was a statistically significant difference between cases and controls in relation to job stress involving high strain (OR = 2.1; 95%CI: 1.1-3.9), which places high demands combined with low job control. High strain in cases in this study represents the highest risk of physical and mental disorders for teachers. Loss of voice prevents teachers from continuing in their professional role, eliminates their professional identity, and jeopardizes their career.

[Relations between extraction of wisdom teeth and temporomandibular disorders: a case/control study].

PubMed

Duval, Florian; Leroux, Agathe; Bertaud, Valérie; Meary, Fleur; Le Padellec, Clément; Refuveille, Laura; Lemaire, Arnaud; Sorel, Olivier; Chauvel-Lebret, Dominique

2015-09-01

The aim of this study was to assess the impact of extraction of third molars on the occurrence of temporo-mandibular disorders (TMD). A review of the literature and a case-control study have been conducted. The case-control study compares the frequency of extraction of third molars between the sample with TMD (case) and the sample without TMD (control). The proportion of patients who had undergone extractions of wisdom teeth was higher in the case group than in the control group. The difference was statistically significant when patients had undergone extraction of all four wisdom teeth or when the extraction of four wisdom teeth underwent in one sitting or under general anesthesia. The study of patients in case sample shows that all signs of TMD were more common in patients who had undergone extractions in several sessions and under local anesthesia. The temporomandibular joint sounds are significantly more frequent with local anesthesia. In the case group, 85 to 92% of patients have parafunctions and 5 to 11% have malocclusion. This demonstrates the multifactorial etiology of temporomandibular disorders. © EDP Sciences, SFODF, 2015.

Pernicious anemia and colorectal cancer risk - A nested case-control study.

PubMed

Boursi, Ben; Mamtani, Ronac; Haynes, Kevin; Yang, Yu-Xiao

2016-11-01

Hypergastrinemia was shown to stimulate colonic epithelial cell proliferation. To evaluate the association between pernicious anemia (PA), a disease with hypergastrinemia, and colorectal cancer (CRC) risk. We conducted a nested case-control study within a large database from the UK. Cases were defined as all individuals in the cohort with at least one medical code for CRC. Controls were selected based on incidence-density sampling. For each case, up to four eligible controls were matched on age at diagnosis, sex, practice-site, and both duration and calendar time of follow-up. Exposure of interest was diagnosis of PA prior to CRC diagnosis date. The primary analysis was a multivariable conditional logistic regression. Our study included 22,098 CRC cases and 85,969 matched controls. We identified 154 (0.70%) cases and 563 (0.65%) controls with past history of PA. The adjusted OR for the association between PA and CRC risk was 1.02 (95% CI 0.85-1.22). There was no difference in the results after stratification according to sex. In a sensitivity analysis only among individuals without chronic use of proton pump inhibitors (PPIs) the adjusted OR was 1.14 (95% CI 0.90-1.45). There was no association between duration of PA and CRC risk. PA is not associated with higher CRC risk. Copyright © 2016. Published by Elsevier Ltd.

Medication safety research by observational study design.

PubMed

Lao, Kim S J; Chui, Celine S L; Man, Kenneth K C; Lau, Wallis C Y; Chan, Esther W; Wong, Ian C K

2016-06-01

Observational studies have been recognised to be essential for investigating the safety profile of medications. Numerous observational studies have been conducted on the platform of large population databases, which provide adequate sample size and follow-up length to detect infrequent and/or delayed clinical outcomes. Cohort and case-control are well-accepted traditional methodologies for hypothesis testing, while within-individual study designs are developing and evolving, addressing previous known methodological limitations to reduce confounding and bias. Respective examples of observational studies of different study designs using medical databases are shown. Methodology characteristics, study assumptions, strengths and weaknesses of each method are discussed in this review.

Exposure to pistachio pesticides and stillbirth: a case-control study.

PubMed

Razi, Saeid; Rezaeian, Mohsen; Dehkordi, Fatemeh Ghani; Manshoori, Azita; Goujani, Reza; Vazirinejad, Reza

2016-01-01

Stillbirth is an undesirable outcome of pregnancy. In light of the increasing use of pesticides and growing concerns about the possible health effects of agricultural pesticides, we investigated the effect of exposure to pistachio pesticides on stillbirth in pregnant mothers. This case-control study was conducted in Rafsanjan, Iran from 2011 to 2012. A total of 125 females who had a recent stillbirth were included as the case group, and 250 controls were selected from females who had a recent live birth. For each case, two controls with the nearest propensity score to the case were selected. Data were collected using a protocol developed by the researcher that involved interviewing respondents and reviewing their medical records. Conditional multivariate and univariate logistic regression analysis were performed and odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. The ORs of stillbirth in mothers living in pistachio gardens and those who were exposed to sprayed pesticides, in comparison to the controls, were 14.1 (95% CI, 3.3 to 63.4) and 5.0 (95% CI, 1.2 to 28.6), respectively. No significant differences were found in stillbirth rates according to the distance between the mother's residence and a pistachio garden or involvement in agricultural activities. The results of our study showed that exposure to pistachio pesticides during pregnancy may increase the likelihood of stillbirth in mothers.

Reusable experiment controllers, case studies

NASA Astrophysics Data System (ADS)

Buckley, Brian A.; Gaasbeck, Jim Van

1996-03-01

Congress has given NASA and the science community a reality check. The tight and ever shrinking budgets are trimming the fat from many space science programs. No longer can a Principal Investigator (PI) afford to waste development dollars on re-inventing spacecraft controllers, experiment/payload controllers, ground control systems, or test sets. Inheritance of the Ground Support Equipment (GSE) from one program to another is not a significant re-use of technology to develop a science mission in these times. Reduction of operational staff and highly autonomous experiments are needed to reduce the sustaining cost of a mission. The re-use of an infrastructure from one program to another is needed to truly attain the cost and time savings required. Interface and Control Systems, Inc. (ICS) has a long history of re-usable software. Navy, Air Force, and NASA programs have benefited from the re-use of a common control system from program to program. Several standardization efforts in the AIAA have adopted the Spacecraft Command Language (SCL) architecture as a point solution to satisfy requirements for re-use and autonomy. The Environmental Research Institute of Michigan (ERIM) has been a long-standing customer of ICS and are working on their 4th generation system using SCL. Much of the hardware and software infrastructure has been re-used from mission to mission with little cost for re-hosting a new experiment. The same software infrastructure has successfully been used on Clementine, and an end-to-end system is being deployed for the Far Ultraviolet Spectroscopic Explorer (FUSE) for Johns Hopkins University. A case study of the ERIM programs, Clementine and FUSE will be detailed in this paper.

Risk factors for measles among adults in Tianjin, China: Who should be controls in a case-control study?

PubMed

Wagner, Abram L; Boulton, Matthew L; Gillespie, Brenda W; Zhang, Ying; Ding, Yaxing; Carlson, Bradley F; Luo, Xiaoyan; Montgomery, JoLynn P; Wang, Xiexiu

2017-01-01

Control groups in previous case-control studies of vaccine-preventable diseases have included people immune to disease. This study examines risk factors for measles acquisition among adults 20 to 49 years of age in Tianjin, China, and compares findings using measles IgG antibody-negative controls to all controls, both IgG-negative and IgG-positive. Measles cases were sampled from a disease registry, and controls were enrolled from community registries in Tianjin, China, 2011-2015. Through a best subsets selection procedure, we compared which variables were selected at different model sizes when using IgG-negative controls or all controls. We entered risk factors for measles in two separate logistic regression models: one with measles IgG-negative controls and the other with all controls. The study included 384 measles cases and 1,596 community controls (194 IgG-negative). Visiting a hospital was an important risk factor. For specialty hospitals, the odds ratio (OR) was 4.53 (95% confidence interval (CI): 1.28, 16.03) using IgG-negative controls, and OR = 5.27 (95% CI: 2.73, 10.18) using all controls. Variables, such as age or length of time in Tianjin, were differentially selected depending on the control group. Individuals living in Tianjin ≤3 years had 2.87 (95% CI: 1.46, 5.66) times greater odds of measles case status compared to all controls, but this relationship was not apparent for IgG-negative controls. We recommend that case-control studies examining risk factors for infectious diseases, particularly in the context of transmission dynamics, consider antibody-negative controls as the gold standard.

Cerebral malaria and sequelar epilepsy: first matched case-control study in Gabon.

PubMed

Ngoungou, Edgard Brice; Koko, Jean; Druet-Cabanac, Michel; Assengone-Zeh-Nguema, Yvonne; Launay, Marylène Ndong; Engohang, Edouard; Moubeka-Mounguengui, Martine; Kouna-Ndouongo, Philomène; Loembe, Paul-Marie; Preux, Pierre-Marie; Kombila, Maryvonne

2006-12-01

Cerebral malaria (CM) is suspected to be a potential cause of epilepsy in tropical areas. The purpose of this article was to evaluate the relationship between CM and epilepsy in Gabon. A matched case-control study was carried out on a sample of subjects aged six months to 25 years and hospitalized between 1990 and 2004 in three hospitals in Libreville, Gabon. Cases were defined as patients suffering from epilepsy and confirmed by a neurologist. Controls were defined as patients without epilepsy. The exposure of interest was CM according to WHO criteria. In total, 296 cases and 296 controls were included. Of these, 36 (26 cases and 10 controls) had a CM history. The adjusted odds ratio (aOR) to develop epilepsy after CM was 3.9 [95% CI: 1.7-8.9], p<0.001. Additional risk factors were identified: family history of epilepsy: aOR=6.0 [95% CI: 2.6-14.1], p<0.0001, and febrile convulsions: aOR=9.2 [95% CI 4.0-21.1], p<0.0001. This first case-control study on that issue suggests that epilepsy-related CM is an underrecognized problem. It emphasizes the need for further studies to better evaluate the role of convulsions during CM.

Raised-Line Pictures, Blindness, and Tactile "Beliefs": An Observational Case Study

ERIC Educational Resources Information Center

D'Angiulli, Amedeo

2007-01-01

In this observational case study, a 13-year old boy, Carlo, who was born completely blind, was invited to explore and identify, a set of raised-line pictures without receiving feedback about the accuracy of his identification. He was then asked to explain, verbally or by drawing, why he believed that the names he suggested accurately identified…

Individual socioeconomic status and breast cancer diagnostic stages: a French case-control study.

PubMed

Orsini, Mattea; Trétarre, Brigitte; Daurès, Jean-Pierre; Bessaoud, Faiza

2016-06-01

Health inequalities have increased over the last 30 years. Our goal was to investigate the relationship between low individual socioeconomic status and poor breast cancer prognosis. Our hypothesis was: low socioeconomic status patients have a higher risk of being diagnosed with late stage breast cancer than high socioeconomic status ones due to delayed diagnosis. We conducted a matched case-control study on 619 women with breast cancer, living in the Hérault, a French administrative area. Both Cases and Controls were recruited among invasive cases diagnosed in 2011 and 2012 and treated in Hérault care centers. Cases were defined as patients with advanced stages. Controls were composed of early stage patients. Individual socioeconomic status was assessed using a validated individual score adapted to the French population and health care system. We observed that low socioeconomic status patients have a 2-fold risk of having late stage breast cancer regardless of cancer characteristics and detection mode (screening vs. clinical signs). One reason explaining those results could be that low socioeconomic status patients have less regular follow-up which can lead to later and poorer diagnosis. Follow-up is improved for women with a better awareness of breast cancer. Health policy makers could reduce health inequalities by reducing the delay in breast cancer diagnosis for low socioeconomic status women. © The Author 2016. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

Plasma carotenoids, retinol, and tocopherols and postmenopausal breast cancer risk in the Multiethnic Cohort Study: a nested case-control study

PubMed Central

Epplein, Meira; Shvetsov, Yurii B; Wilkens, Lynne R; Franke, Adrian A; Cooney, Robert V; Le Marchand, Loïc; Henderson, Brian E; Kolonel, Laurence N; Goodman, Marc T

2009-01-01

Introduction Assessments by the handful of prospective studies of the association of serum antioxidants and breast cancer risk have yielded inconsistent results. This multiethnic nested case-control study sought to examine the association of plasma carotenoids, retinol, and tocopherols with postmenopausal breast cancer risk. Methods From the biospecimen subcohort of the Multiethnic Cohort Study, 286 incident postmenopausal breast cancer cases were matched to 535 controls on age, sex, ethnicity, study location (Hawaii or California), smoking status, date/time of collection and hours of fasting. We measured prediagnostic circulating levels of individual carotenoids, retinol, and tocopherols. Conditional logistic regression was used to compute odds ratios and 95% confidence intervals. Results Women with breast cancer tended to have lower levels of plasma carotenoids and tocopherols than matched controls, but the differences were not large or statistically significant and the trends were not monotonic. No association was seen with retinol. A sensitivity analysis excluding cases diagnosed within 1 year after blood draw did not alter the findings. Conclusions The lack of significant associations in this multiethnic population is consistent with previously observed results from less racially-diverse cohorts and serves as further evidence against a causal link between plasma micronutrient concentrations and postmenopausal breast cancer risk. PMID:19619335

A Data Management System for Multi-Phase Case-Control Studies

PubMed Central

Gibeau, Joanne M.; Steinfeldt, Lois C.; Stine, Mark J.; Tullis, Katherine V.; Lynch, H. Keith

1983-01-01

The design of a computerized system for the management of data in multi-phase epidemiologic case-control studies is described. Typical study phases include case-control selection, abstracting of data from medical records, and interview of study subjects or next of kin. In consultation with project personnel, requirements for the system were established: integration of data from all study phases into one data base, accurate follow-up of subjects through the study, sophisticated data editing capabilities, ready accessibility of specified programs to project personnel, and generation of current status and exception reports for project managment. SIR (Scientific Information Retrieval), a commercially available data base management system, was selected as the foundation of this system. The system forms a comprehensive data management system applicable to many types of public health research studies.

Low Control and High Demands at Work as Risk Factors for Suicide: An Australian National Population-Level Case-Control Study.

PubMed

Milner, Allison; Spittal, Matthew J; Pirkis, Jane; Chastang, Jean-François; Niedhammer, Isabelle; LaMontagne, Anthony D

2017-04-01

Previous research suggests that psychosocial job stressors may be plausible risk factors for suicide. This study assessed the relationship between psychosocial job stressors and suicide mortality across the Australian population. We developed a job exposure matrix to objectively measure job stressors across the working population. Suicide data came from a nationwide coronial register. Living controls were selected from a nationally representative cohort study. Incidence density sampling was used to ensure that controls were sampled at the time of death of each case. The period of observation for both cases and controls was 2001 to 2012. We used multilevel logistic regression to assess the odds of suicide in relation to 2 psychosocial job stressors (job control and job demands), after matching for age, sex, and year of death/survey and adjusting for socioeconomic status. Across 9,010 cases and 14,007 matched controls, our results suggest that low job control (odds ratio [OR], 1.35; 95% confidence interval [CI], 1.26-1.44; p < .001) and high job demands (OR, 1.36; 95% CI, 1.26-1.46; p < .001) were associated with increased odds of male suicide after adjusting for socioeconomic status. High demands were associated with lower odds of female suicide (OR, 0.81; 95% CI, 0.72-0.92; p = .002). It seems that adverse experiences at work are a risk factor for male suicide while not being associated with an elevated risk among females. Future studies on job stressors and suicide are needed, both to further understand the biobehavioral mechanisms explaining the link between job stress and suicide, and to inform targeted prevention initiatives.

[Application of nested case-control study on safe evaluation of post-marketing traditional Chinese medicine injection].

PubMed

Xiao, Ying; Zhao, Yubin; Xie, Yanming

2011-10-01

The nested case-control study design (or the case-control in a cohort study) is described here as a new study design used in safe evaluation of post-marketing traditional Chinese medicine injection. In the nested case-control study, cases of a disease that occur in a defined cohort are identified and, for each, a specified number of matched controls is selected from among those in the cohort who have not developed the disease by the time of disease occurrence in the case. For many research questions, the nested case-control design potentially offers impressive reductions in costs and efforts of data collection and analysis compared with the full cohort approach, with relatively minor loss in statistical efficiency. The nested case-control design is particularly advantageous for studies in safe evaluation of post-marketing traditional Chinese medicine injection. Some examples of the application of nested case-control study were given.

Leptospira Exposure and Gardeners: A Case-Control Seroprevalence Study

PubMed Central

Alvarado-Esquivel, Cosme; Hernandez-Tinoco, Jesus; Sanchez-Anguiano, Luis Francisco; Ramos-Nevarez, Agar; Cerrillo-Soto, Sandra Margarita; Guido-Arreola, Carlos Alberto

2016-01-01

Background Leptospira can be found in soil. However, it is unclear whether occupational exposure to soil may represent a risk for Leptospira infection in humans. Therefore, we sought to determine the association of Leptospira IgG seroprevalence with the occupation of gardener, and to determine the epidemiological characteristics of gardeners associated with Leptospira exposure. Methods We performed a case-control study in 168 gardeners and 168 age- and gender-matched control subjects without gardening occupation in Durango City, Mexico. The seroprevalence of anti-Leptospira IgG antibodies in cases and controls was determined using an enzyme immunoassay. Bivariate and multivariate analyses were used to assess the association of Leptospira exposure and the characteristics of the gardeners. Results Anti-Leptospira IgG antibodies were found in 10 (6%) of 168 gardeners and in 15 (8.9%) of 168 control subjects (odds ratio (OR): 0.64; 95% confidence interval (CI): 0.28 - 1.48; P = 0.40). Multivariate analysis showed that Leptospira seropositivity was positively associated with female gender (OR: 5.82; 95% CI: 1.11 - 30.46; P = 0.03), and negatively associated with eating while working (OR: 0.21; 95% CI: 0.05 - 0.87; P = 0.03). In addition, multivariate analysis showed that high anti-Leptospira levels were associated with consumption of boar meat (OR: 28.00; 95% CI: 1.20 - 648.80; P = 0.03). Conclusions This is the first case-control study of Leptospira exposure in gardeners. Results do not support an association of Leptospira exposure with the occupation of gardener. However, further studies to confirm the lack of this association are needed. The potential role of consumption of boar meat in Leptospira infection deserves further investigation. PMID:26668679

Baldness and testicular cancer: the EPSAM case-control study.

PubMed

Moirano, G; Zugna, D; Grasso, C; Lista, P; Ciuffreda, L; Segnan, N; Merletti, F; Richiardi, L

2016-03-01

The etiology of testicular cancer is largely unexplained. Research has mainly focused on prenatal exposures, especially to sex hormones, while less attention has been paid to exposures that may act also postnatally. As baldness has been previously associated with testicular cancer risk we focused on baldness and body hairiness, which are both associated with androgen activity. We used data of the Postnatal Exposures and Male Health (EPSAM) study, a case-control study on testicular cancer conducted in the Province of Turin, Italy, involving cases diagnosed between 1997 and 2008. Information was collected using mailed questionnaires. Analyses included 255 cases and 459 controls. We calculated ORs and 95% CIs to estimate testicular cancer risk among those who developed baldness and among those with body hairiness. We found an inverse association between testicular cancer and baldness (OR: 0.67, 95% CI: 0.46-0.98) and body hairiness (OR: 0.78, 95% CI: 0.53-1.16), although the latter had wider CIs. The inverse association between baldness and testicular cancer is consistent with the results from previous studies. These results suggest that androgens activity may influence testicular cancer risk. © 2016 American Society of Andrology and European Academy of Andrology.

Higher sweat chloride levels in patients with asthma: a case-control study.

PubMed

Awasthi, Shally; Dixit, Pratibha; Maurya, Nutan

2015-02-01

To screen asthmatic patients by sweat chloride test to identify proportion with Cystic Fibrosis (CF); (Sweat chloride level >60 mmol/L). Also, to compare sweat chloride levels between cases of bronchial asthma and age and sex matched healthy children aged 5 mo-15 y. The present case-control study was conducted in a tertiary care hospital in India. Cases of bronchial asthma, diagnosed by GINA guideline 2008, and age matched healthy controls were included. Case to control ratio was 2:1. Sweat Chloride test was done by Pilocarpine Iontophoresis method. From April 2010 through May 2012, 216 asthmatics and 112 controls were recruited. Among asthmatics, there was no case of Cystic Fibrosis. Mean sweat chloride levels in asthmatics was 22.39 ± 8.45 mmol/L (inter-quartile range - 15-28 mmol/L) and in controls 19.55 ± 7.04 mmol/L (inter-quartile range - 15-23.5 mmol/L) (p value = 0.048). No Cystic Fibrosis case was identified among asthmatics. Mean sweat chloride levels were higher in asthmatics as compared to controls.

Association between diabetes and tuberculosis: case-control study.

PubMed

Pereira, Susan Martins; Araújo, Gleide Santos de; Santos, Carlos Antônio de Souza Teles; Oliveira, Maeli Gomes de; Barreto, Maurício Lima

2016-12-22

To test the association between diabetes and tuberculosis. It is a case-control study, matched by age and sex. We included 323 new cases of tuberculosis with positive results for bacilloscopy. The controls were 323 respiratory symptomatic patients with negative bacilloscopy, from the same health services, such as: ambulatory cases from three referral hospitals and six basic health units responsible for the notifications of new cases of tuberculosis in Salvador, Bahia. Data collection occurred between 2008 and 2010. The instruments used were structured interview, including clinical data, capillary blood glucose (during fasting or postprandial), and the CAGE questionnaire for screening of abusive consumption of alcohol. Descriptive, exploratory, and multivariate analysis was performed using conditional logistic regression. The average age of the cases was 38.5 (SD = 14.2) years and of the controls, 38.5 (SD = 14.3) years. Among cases and controls, most subjects (61%) were male. In univariate analysis we found association between the occurrence of diabetes and tuberculosis (OR = 2.37; 95%CI 1.04-5.42), which remained statistically significant after adjustment for potential confounders (OR = 3.12; 95%CI 1.12-7.94). The association between diabetes and tuberculosis can hinder the control of tuberculosis, contributing to the maintainance of the disease burden. The situation demands increasing early detection of diabetes among people with tuberculosis, in an attempt to improve disease control strategies. Testar a associação entre diabetes e tuberculose. Trata-se de estudo caso-controle, pareado por idade e sexo. Foram incluídos 323 casos novos de tuberculose com resultados positivos à baciloscopia. Os controles foram 323 sintomáticos respiratórios com baciloscopia negativa, oriundos dos mesmos serviços de saúde dos casos: ambulatórios de três hospitais de referência e seis unidades básicas de saúde responsáveis pelas notificações dos casos novos de

Evaluating the Impact of Database Heterogeneity on Observational Study Results

PubMed Central

Madigan, David; Ryan, Patrick B.; Schuemie, Martijn; Stang, Paul E.; Overhage, J. Marc; Hartzema, Abraham G.; Suchard, Marc A.; DuMouchel, William; Berlin, Jesse A.

2013-01-01

Clinical studies that use observational databases to evaluate the effects of medical products have become commonplace. Such studies begin by selecting a particular database, a decision that published papers invariably report but do not discuss. Studies of the same issue in different databases, however, can and do generate different results, sometimes with strikingly different clinical implications. In this paper, we systematically study heterogeneity among databases, holding other study methods constant, by exploring relative risk estimates for 53 drug-outcome pairs and 2 widely used study designs (cohort studies and self-controlled case series) across 10 observational databases. When holding the study design constant, our analysis shows that estimated relative risks range from a statistically significant decreased risk to a statistically significant increased risk in 11 of 53 (21%) of drug-outcome pairs that use a cohort design and 19 of 53 (36%) of drug-outcome pairs that use a self-controlled case series design. This exceeds the proportion of pairs that were consistent across databases in both direction and statistical significance, which was 9 of 53 (17%) for cohort studies and 5 of 53 (9%) for self-controlled case series. Our findings show that clinical studies that use observational databases can be sensitive to the choice of database. More attention is needed to consider how the choice of data source may be affecting results. PMID:23648805

Case-control study of smoking and non-melanoma skin cancer.

PubMed

Rollison, Dana E; Iannacone, Michelle R; Messina, Jane L; Glass, L Frank; Giuliano, Anna R; Roetzheim, Richard G; Cherpelis, Basil S; Fenske, Neil A; Jonathan, Kristen A; Sondak, Vernon K

2012-02-01

To investigate the association between cigarette smoking and basal and squamous cell carcinomas (BCC and SCC) of the skin, a clinic-based case-control study was conducted in Tampa, FL. Patients with histologically confirmed BCC/SCC were recruited from a university dermatology clinic (n = 215 BCC, 165 SCC). Controls were comprised of individuals with no history of skin cancer who screened negative for skin cancer upon physical examination at the affiliated cancer screening or primary care clinics (n = 315). Information on smoking and other risk factors was obtained from self-administered questionnaires. After adjustment for age, sex, and other skin cancer-risk factors, ever smoking was not associated with BCC (odds ratio (OR) = 1.26, 95% confidence interval (CI) = 0.83-1.92), but was statistically significantly associated with SCC (OR = 1.97, 95% CI = 1.19-3.26), with significant trends observed for SCC associated with increasing cigarettes per day (p = 0.01) and pack-years smoked (p = 0.01). Among men, smoking ≥20 pack-years was associated with non-significant increased risks of BCC (OR = 1.90, 95% CI = 0.88-4.12) and SCC (OR = 1.97, 95% CI = 0.84-4.66), whereas among women, no association was observed with BCC (OR = 0.98, 95% CI = 0.39-2.46) while a statistically significant three-fold risk was observed with SCC (OR = 3.00, 95% CI = 1.02-8.80). Cigarette smoking is more strongly associated with SCC than BCC, particularly among women.

Maternal sepsis: a Scottish population-based case-control study.

PubMed

Acosta, C D; Bhattacharya, S; Tuffnell, D; Kurinczuk, J J; Knight, M

2012-03-01

To describe the risk of maternal sepsis associated with obesity and other understudied risk factors such as operative vaginal delivery. Population-based, case-control study. North NHS region of Scotland. All cases of pregnant, intrapartum and postpartum women with International Classification of Disease-9 codes for sepsis or severe sepsis recorded in the Aberdeen Maternal and Neonatal Databank (AMND) from 1986 to 2009. Four controls per case selected from the AMND were frequency matched on year-of-delivery. Cases and controls were compared; significant variables from univariable regression were adjusted in a multivariable logistic regression model. Dependent variables were uncomplicated sepsis or severe ('near-miss') sepsis. Independent variables were demographic, medical and clinical delivery characteristics. Unadjusted and adjusted odds ratios (OR) with 95% confidence intervals (95% CI) are reported. Controlling for mode of delivery and demographic and clinical factors, obese women had twice the odds of uncomplicated sepsis (OR 2.12; 95% CI 1.14-3.89) compared with women of normal weight. Age <25 years (OR 5.15; 95% CI 2.43-10.90) and operative vaginal delivery (OR 2.20; 95% CI 1.02-4.87) were also significant predictors of sepsis. Known risk factors for maternal sepsis were also significant in this study (OR for uncomplicated and severe sepsis respectively): multiparity (OR 6.29, 12.04), anaemia (OR 3.43, 18.49), labour induction (OR 3.92 severe only), caesarean section (OR 3.23, 13.35), and preterm birth (OR 2.46 uncomplicated only). Obesity, operative vaginal delivery and age <25 years are significant risk factors for sepsis and should be considered in clinical obstetric care. © 2012 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2012 RCOG.

Intrapartum fetal heart rate patterns of trisomy 21 fetuses: A case-control study.

PubMed

Koren, Inbal; Michaelson-Cohen, Rachel; Chen, Daniela; Michaeli, Jennia; Schimmel, Michael; Tsafrir, Avi; Shen, Ori

2016-01-01

To determine whether there are specific characteristic intrapartum heart rate patterns for fetuses with trisomy 21(T21). Intrapartum fetal heart rate (FHR) tracings of T21 fetuses were compared to those of euploid fetuses in a retrospective, observational, matched, case-control study. The study group consisted of 42 fetuses with T21 and 42 matched euploid controls. Matching was designed to accommodate possible confounders. The sign test and McNemar's test were used for categorical variables. The paired t test was used for comparison between quantitative variables. Intrapartum baseline FHR of fetuses with T21 was found to be slightly decreased compared to controls (122.5 vs 129.05 beats per minute, p=0.028). No differences were detected in the presence of periodic changes, or FHR variability between the groups. When evaluating intrapartum FHR of fetuses with T21, decreased baseline FHR can be expected. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Assessing validity of observational intervention studies – the Benchmarking Controlled Trials

PubMed Central

Malmivaara, Antti

2016-01-01

Abstract Background: Benchmarking Controlled Trial (BCT) is a concept which covers all observational studies aiming to assess impact of interventions or health care system features to patients and populations. Aims: To create and pilot test a checklist for appraising methodological validity of a BCT. Methods: The checklist was created by extracting the most essential elements from the comprehensive set of criteria in the previous paper on BCTs. Also checklists and scientific papers on observational studies and respective systematic reviews were utilized. Ten BCTs published in the Lancet and in the New England Journal of Medicine were used to assess feasibility of the created checklist. Results: The appraised studies seem to have several methodological limitations, some of which could be avoided in planning, conducting and reporting phases of the studies. Conclusions: The checklist can be used for planning, conducting, reporting, reviewing, and critical reading of observational intervention studies. However, the piloted checklist should be validated in further studies.Key messagesBenchmarking Controlled Trial (BCT) is a concept which covers all observational studies aiming to assess impact of interventions or health care system features to patients and populations.This paper presents a checklist for appraising methodological validity of BCTs and pilot-tests the checklist with ten BCTs published in leading medical journals. The appraised studies seem to have several methodological limitations, some of which could be avoided in planning, conducting and reporting phases of the studies.The checklist can be used for planning, conducting, reporting, reviewing, and critical reading of observational intervention studies. PMID:27238631

Association of atrial fibrillation and cancer: Analysis from two large population-based case-control studies.

PubMed

Saliba, Walid; Rennert, Hedy S; Gronich, Naomi; Gruber, Stephen B; Rennert, Gad

2018-01-01

An association between atrial fibrillation (AF) and risk of cancer has been suggested in several studies, including prospective cohort studies. However, the magnitude and the temporal nature of this association remain unclear. Data from two large prospective population-based case-control studies, the Molecular Epidemiology of Colorectal Cancer (MECC, n = 8,383) and the Breast Cancer in Northern Israel Study (BCINIS, n = 11,608), were used to better understand the nature and temporality of a possible association between cancer diagnosis and AF events before and after cancer diagnosis. A case-control study approach was employed to study prior AF as a risk factor for cancer, and a cohort study approach was employed to study incident cancer as a risk factor for AF. AF was associated with a significant reduced odds of cancer as reflected in the case-control approach, with an adjusted OR = 0.77 (95% CI, 0.65-0.91), while cancer was not found to be significantly associated with elevated risk of AF in the cohort approach, with an adjusted HR = 1.10 (0.98-1.23). The immediate period (90 days) after an AF event was associated with a 1.85 times increased risk of cancer, and the immediate period after the diagnosis of cancer was associated with a 3.4 fold increased risk of AF. These findings probably reflect both the effect of acute transient conditions associated with new cancer diagnosis and detection bias. Similar results were identified with colorectal and breast cancer cases. Atrial fibrillation of longer than 90 days duration is associated with reduced odds of new cancer diagnosis. The results of this study suggest that an association observed in prior research may be due to instances related to cancer diagnosis and detection bias rather than a causal relationship. However, there may be bias in the sampling and residual confounding that distort the associations.

Healthy control subjects are poorly defined in case-control studies of irritable bowel syndrome

PubMed Central

Ghorbani, Shireen; Nejad, Amir; Law, David; Chua, Kathleen S.; Amichai, Meridythe M.; Pimentel, Mark

2015-01-01

Background Case-control studies are vital for understanding the pathophysiology of gastrointestinal disease. While the definition of disease is clear, the definition of healthy control is not. This is particularly relevant for functional bowel diseases such as irritable bowel syndrome (IBS). In this study, a systematic review formed the basis for a prospective study evaluating the effectiveness of commonly used techniques for defining healthy controls in IBS. Methods A systematic review of the literature was conducted to identify case-control studies involving functional gastrointestinal disorders. “Lack of Rome criteria”, self-description as “healthy” and the bowel disease questionnaire (BDQ) were common methods for identifying healthy controls. These 3 methods were then applied to a cohort of 53 non-patient subjects to determine their validity compared to objective outcome measures (7-day stool diary). Results “Lack of Rome criteria” and “healthy” self-description were the most common methods for identifying healthy control subjects, but many studies failed to describe the methods used. In the prospective study, more subjects were identified as non-healthy using the BDQ than using either lack of Rome criteria (P=0.01) or “healthy” self-description (P=0.026). Furthermore, stool diaries identified several subjects with abnormal stool form and/or frequency which were not identified using lack of Rome criteria or the “healthy” question. Comparisons revealed no agreement (κ) between the different methods for defining healthy controls. Conclusions The definitions of healthy controls in studies of functional bowel diseases such as IBS are inconsistent. Since functional symptoms are common, a strict definition of “normal” is needed in this area of research. PMID:25609236

Risk factors for neural tube defects in Riyadh City, Saudi Arabia: Case-control study.

PubMed

Salih, Mustafa A M; Murshid, Waleed R; Mohamed, Ashry Gad; Ignacio, Lena C; de Jesus, Julie E; Baabbad, Rubana; El Bushra, Hassan M

2014-01-01

Both genetic and non-genetic environmental factors are involved in the etiology of neural tube defects (NTD) which affect 0.5-2/1000 pregnancies worldwide. This study aimed to explore the risk factors for the development of NTD in Saudi population, and highlight identifiable and preventable causes. Similar studies are scarce in similar populations ofthe Arabian Peninsula and North Africa. This is an unmatched concurrent case-control study including NTD cases born at King Khalid University Hospital, Riyadh during a 4-year period (2002-2006). The case-control study included 25 cases and 125 controls (case: control ratio of 1:5). Years of formal education, employment, household environment (including availability of air conditioning) and rate of parental consanguinity did not differ between mothers of cases and controls. Significantly higher proportion of mothers of cases had history of stillbirth compared to control mothers (16% vs 4.1%, P=0.02). Also family history of hydrocephalus and congenital anomalies were more prevalent in cases than controls (P values=0.0000 and 0.003, respectively). There was significant protective effect of periconceptional folic acid consumption both prior to conception (OR 0.02, 95% CI 0.00-0.07) and during the first 6 weeks of conception (OR 0.13, 95% CI 0.04-0.39). Further research, including a larger cohort, is required to enable ascertainment of gene-nutrient and gene environment interactions associated with NTD in Saudi Arabia.

Simple F Test Reveals Gene-Gene Interactions in Case-Control Studies

PubMed Central

Chen, Guanjie; Yuan, Ao; Zhou, Jie; Bentley, Amy R.; Adeyemo, Adebowale; Rotimi, Charles N.

2012-01-01

Missing heritability is still a challenge for Genome Wide Association Studies (GWAS). Gene-gene interactions may partially explain this residual genetic influence and contribute broadly to complex disease. To analyze the gene-gene interactions in case-control studies of complex disease, we propose a simple, non-parametric method that utilizes the F-statistic. This approach consists of three steps. First, we examine the joint distribution of a pair of SNPs in cases and controls separately. Second, an F-test is used to evaluate the ratio of dependence in cases to that of controls. Finally, results are adjusted for multiple tests. This method was used to evaluate gene-gene interactions that are associated with risk of Type 2 Diabetes among African Americans in the Howard University Family Study. We identified 18 gene-gene interactions (P < 0.0001). Compared with the commonly-used logistical regression method, we demonstrate that the F-ratio test is an efficient approach to measuring gene-gene interactions, especially for studies with limited sample size. PMID:22837643

Exploring interprofessional, interagency multimorbidity care: case study based observational research

PubMed Central

McKinlay, Eileen M.; Morgan, Sonya J.; Gray, Ben V.; Macdonald, Lindsay M.; Pullon, Susan R.H.

2017-01-01

Background The increase in multimorbidity or co-occurring chronic illnesses is a leading healthcare concern. Patients with multimorbidity require ongoing care from many different professionals and agencies, and often report a lack of integrated care. Objective To explore the daily help-seeking behaviours of patients with multimorbidity, including which health professionals they seek help from, how professionals work together, and perceptions and characteristics of effective interprofessional, interagency multimorbidity care. Design Using a case study observational research design, multiple data sources were assembled for four patients with multimorbidity, identified by two general practitioners in New Zealand. In this paper, two case studies are presented, including the recorded instances of contact and communication between patients and professionals, and between professionals. Professional interactions were categorized as consultation, coordination, or collaboration. Results The two case studies illustrated two female patients with likely similar educational levels, but with different profiles of multimorbidity, social circumstances, and personal capabilities, involving various professionals and agencies. Engagement between professionals showed varying levels of interaction and a lack of clarity about leadership or care coordination. The majority of interactions were one-to-one consultations and rarely involved coordination and collaboration. Patients were rarely included in communications between professionals. Conclusion Cases constructed from multiple data sources illustrate the complexity of day-to-day, interprofessional, interagency multimorbidity care. While consultation is the most frequent mode of professional interaction, targeted coordinated and collaborative interactions (including the patient) are highly effective activities. Greater attention should be given to developing and facilitating these interactions and determining who should lead them. PMID

An observation tool to study air traffic control and flightdeck collaboration.

PubMed

Cox, Gemma; Sharples, Sarah; Stedmon, Alex; Wilson, John

2007-07-01

The complex systems of the flightdeck (FD) and the Air Traffic Control Centre (ATC) are characterised by numerous concurrently operating and interacting communication channels between people and between people and machines/computer systems. This paper describes work in support of investigating the impact of changes to technologies and responsibilities within this system with respect to human factors. It focuses primarily on the introduction of datalink (text-based communication rather than traditional radio communication) and the move towards freeflight (pilot-mediated air traffic control). Air traffic management investigations have outlined these specific changes as strategies to enable further increases in the volume of air traffic. A systems approach was taken and field studies were conducted. Small numbers of domain experts such as air traffic controllers (ATCOs) were involved in the field-based observations of how people interact with systems and each other. This paper summarises the overall research approach taken and then specifically reports on the field-based observations including the justification, development, and findings of the observation tool used. The observation tool examined information propagation through the air traffic control-flightdeck (ATC-FD) system, and resulted in models of possible information trajectories through the system.

Alcohol and Difficulty Conceiving in the SUN Cohort: A Nested Case-Control Study.

PubMed

Lopez-del Burgo, Cristina; Gea, Alfredo; de Irala, Jokin; Martínez-González, Miguel A; Chavarro, Jorge E; Toledo, Estefania

2015-07-27

The role of alcohol on fertility remains unclear. We aimed to investigate the association between alcohol and specific alcoholic beverages consumption and the risk of difficulty getting pregnant. We used a case-control study nested within the Seguimiento Universidad de Navarra (SUN) cohort, a prospective, dynamic and multipurpose cohort of 21,705 Spanish university graduates, followed biennially with mailed questionnaires. We identified 686 case-control pairs, matched for age and time in the cohort. Cases were women reporting difficulty getting pregnant. Controls did not consult due to difficulty conceiving and had at least one child during follow-up. After adjustment for potential confounders, we found no association between self-reported difficulty getting pregnant and the number of alcoholic beverages consumed per week, (Odds Ratio [OR] > 5 drinks/week vs. none = 1.04, 95% Confidence Interval [CI] = 0.72-1.51). No association between types of alcoholic beverage and difficulty conceiving (OR > 5 drinks of wine/week vs. none = 1.16, 95% CI = 0.72-1.88; OR > 5 drinks of beer/week vs. none = 1.06, 95% CI = 0.82-1.37; OR > 5 drinks of spirits/week vs. none = 1.24, 95% CI = 0.84-1.64) was observed. In conclusion, we found no association between alcohol intake and risk of consulting a physician due to difficulty conceiving. More studies are needed to clearly elucidate the effects of alcohol intake on women's fertility. In the meantime, recommendations about alcohol intake to couples trying to conceive have to be given cautiously.

Alcohol and Difficulty Conceiving in the SUN Cohort: A Nested Case-Control Study

PubMed Central

Lopez-del Burgo, Cristina; Gea, Alfredo; de Irala, Jokin; Martínez-González, Miguel A.; Chavarro, Jorge E.; Toledo, Estefania

2015-01-01

The role of alcohol on fertility remains unclear. We aimed to investigate the association between alcohol and specific alcoholic beverages consumption and the risk of difficulty getting pregnant. We used a case-control study nested within the Seguimiento Universidad de Navarra (SUN) cohort, a prospective, dynamic and multipurpose cohort of 21,705 Spanish university graduates, followed biennially with mailed questionnaires. We identified 686 case-control pairs, matched for age and time in the cohort. Cases were women reporting difficulty getting pregnant. Controls did not consult due to difficulty conceiving and had at least one child during follow-up. After adjustment for potential confounders, we found no association between self-reported difficulty getting pregnant and the number of alcoholic beverages consumed per week, (Odds Ratio [OR] > 5 drinks/week vs. none = 1.04, 95% Confidence Interval [CI] = 0.72–1.51). No association between types of alcoholic beverage and difficulty conceiving (OR > 5 drinks of wine/week vs. none = 1.16, 95% CI = 0.72–1.88; OR > 5 drinks of beer/week vs. none = 1.06, 95% CI = 0.82–1.37; OR > 5 drinks of spirits/week vs. none = 1.24, 95% CI = 0.84–1.64) was observed. In conclusion, we found no association between alcohol intake and risk of consulting a physician due to difficulty conceiving. More studies are needed to clearly elucidate the effects of alcohol intake on women’s fertility. In the meantime, recommendations about alcohol intake to couples trying to conceive have to be given cautiously. PMID:26225997

Effectiveness of reactive oral cholera vaccination in rural Haiti: a case-control study

PubMed Central

Ivers, Louise C; Hilaire, Isabelle J; Teng, Jessica E; Almazor, Charles P; Jerome, J Gregory; Ternier, Ralph; Boncy, Jacques; Buteau, Josiane; Murray, Megan B; Harris, Jason B; Franke, Molly F

2015-01-01

Background Between April and June 2012, a reactive cholera vaccination campaign was conducted in Haiti using an oral inactivated bivalent whole-cell vaccine (BivWC). Methods We conducted a case-control study to estimate field effectiveness of the vaccine. Cases had acute watery diarrhea, sought treatment at one of three participating cholera treatment units from October 24, 2012 through March 9, 2014, and had a stool sample positive for cholera by culture. For each case, four controls (individuals who did not seek treatment for acute watery diarrhea) were matched by location of residence, calendar time, and age. We also conducted a bias-indicator case-control study to assess the likelihood of bias in the vaccine effectiveness (VE) study. Findings During the study period, 114 eligible individuals presented with acute watery diarrhea and were enrolled. 47 were analyzed as cases in the VE case-control study and 42 as cases in the bias-indicator study. In multivariable analyses, VE was 63% [95% confidence interval (CI): 8%–85%] by self-reported vaccination and 58% [95% CI: 13%–80%] for verified vaccination. Neither self-reported nor verified vaccination was significantly associated with non-cholera diarrhea (VE: 18% [95% CI: −208%–−78%] by self-report and −21% [95%CI: −238%–57%] for verified vaccination). Interpretation BivWC oral cholera vaccine was effective in protecting against cholera in Haiti during the study period –from 4 through 24 months after vaccination. Vaccination is an important component of epidemic cholera control efforts. Funding National Institutes of Health, Delivering Oral Vaccines Effectively project, Department of Global Health and Social Medicine at Harvard Medical School. PMID:25701994

Pesticide exposure and lymphohaematopoietic cancers: a case-control study in an agricultural region (Larissa, Thessaly, Greece).

PubMed

Kokouva, Maria; Bitsolas, Nikolaos; Hadjigeorgiou, Georgios M; Rachiotis, George; Papadoulis, Nikolaos; Hadjichristodoulou, Christos

2011-01-04

The causality of lymphohaematopoietic cancers (LHC) is multifactorial and studies investigating the association between chemical exposure and LHC have produced variable results. The aim of this study was to investigate the relationships between exposure to pesticides and LHC in an agricultural region of Greece. A structured questionnaire was employed in a hospital-based case control study to gather information on demographics, occupation, exposure to pesticides, agricultural practices, family and medical history and smoking. To control for confounders, backward conditional and multinomial logistic regression analyses were used. To assess the dose-response relationship between exposure and disease, the chi-square test for trend was used. Three hundred and fifty-four (354) histologically confirmed LHC cases diagnosed from 2004 to 2006 and 455 sex- and age-matched controls were included in the study. Pesticide exposure was associated with total LHC cases (OR 1.46, 95% CI 1.05-2.04), myelodysplastic syndrome (MDS) (OR 1.87, 95% CI 1.00-3.51) and leukaemia (OR 2.14, 95% CI 1.09-4.20). A dose-response pattern was observed for total LHC cases (P = 0.004), MDS (P = 0.024) and leukaemia (P = 0.002). Pesticide exposure was independently associated with total LHC cases (OR 1.41, 95% CI 1.00 - 2.00) and leukaemia (OR 2.05, 95% CI 1.02-4.12) after controlling for age, smoking and family history (cancers, LHC and immunological disorders). Smoking during application of pesticides was strongly associated with total LHC cases (OR 3.29, 95% CI 1.81-5.98), MDS (OR 3.67, 95% CI 1.18-12.11), leukaemia (OR 10.15, 95% CI 2.15-65.69) and lymphoma (OR 2.72, 95% CI 1.02-8.00). This association was even stronger for total LHC cases (OR 18.18, 95% CI 2.38-381.17) when eating simultaneously with pesticide application. Lymphohaematopoietic cancers were associated with pesticide exposure after controlling for confounders. Smoking and eating during pesticide application were identified as

Pesticide exposure and lymphohaematopoietic cancers: a case-control study in an agricultural region (Larissa, Thessaly, Greece)

PubMed Central

2011-01-01

Background The causality of lymphohaematopoietic cancers (LHC) is multifactorial and studies investigating the association between chemical exposure and LHC have produced variable results. The aim of this study was to investigate the relationships between exposure to pesticides and LHC in an agricultural region of Greece. Methods A structured questionnaire was employed in a hospital-based case control study to gather information on demographics, occupation, exposure to pesticides, agricultural practices, family and medical history and smoking. To control for confounders, backward conditional and multinomial logistic regression analyses were used. To assess the dose-response relationship between exposure and disease, the chi-square test for trend was used. Results Three hundred and fifty-four (354) histologically confirmed LHC cases diagnosed from 2004 to 2006 and 455 sex- and age-matched controls were included in the study. Pesticide exposure was associated with total LHC cases (OR 1.46, 95% CI 1.05-2.04), myelodysplastic syndrome (MDS) (OR 1.87, 95% CI 1.00-3.51) and leukaemia (OR 2.14, 95% CI 1.09-4.20). A dose-response pattern was observed for total LHC cases (P = 0.004), MDS (P = 0.024) and leukaemia (P = 0.002). Pesticide exposure was independently associated with total LHC cases (OR 1.41, 95% CI 1.00 - 2.00) and leukaemia (OR 2.05, 95% CI 1.02-4.12) after controlling for age, smoking and family history (cancers, LHC and immunological disorders). Smoking during application of pesticides was strongly associated with total LHC cases (OR 3.29, 95% CI 1.81-5.98), MDS (OR 3.67, 95% CI 1.18-12.11), leukaemia (OR 10.15, 95% CI 2.15-65.69) and lymphoma (OR 2.72, 95% CI 1.02-8.00). This association was even stronger for total LHC cases (OR 18.18, 95% CI 2.38-381.17) when eating simultaneously with pesticide application. Conclusions Lymphohaematopoietic cancers were associated with pesticide exposure after controlling for confounders. Smoking and eating during pesticide

Spinal cord injury and women's sexual life: case-control study.

PubMed

Merghati-Khoei, E; Emami-Razavi, S H; Bakhtiyari, M; Lamyian, M; Hajmirzaei, S; Ton-Tab Haghighi, S; Korte, J E; Maasoumi, R

2017-03-01

Study design :This is a case-control study. The objective of this study was to estimate the magnitude of association between spinal cord injury (SCI) and women's quality of sexual life and sexual function. This study was conducted in the Brain and Spinal Cord Injury Research Center, Tehran University of Medical Sciences, Tehran, Iran. From the referral university-based clinics, we used simple random sampling to recruit 62 women: 31 women with SCI and 31 women without SCI. Socio-demographic and reproductive traits questionnaire, Sexual Quality of life-Female (SQOL-F), Female Sexual Function Index (FSFI) and Spinal Cord Independence Measure (SCIM) were completed using telephone and face-to-face interviews in the cases and controls. After univariate analyses, multivariate linear and proportional odds regression models were conducted to investigate the relation between SCI and women's quality of sexual life, as well as sexual function. The mean age of cases and controls was 35.42±6.51 and 33.77±4.02 years. Most women were high school-educated and housewives. Adjusting for probable confounders, the proportional odds regression model showed a significant relationship between the spinal cord injury (AOR=4.2, 95% CI: 1.8-9.2), non-college-educated (AOR=3.1, 95% CI: 1.2-5.9) and employed (AOR=1.8, 95% CI: 1.1-1.8) variables and being in one of the moderate or poor quality of life classes. Scores of SQOL-F and FSFI domains, except satisfaction, were significantly worse in cases versus controls (P<0.001). Although our participants showed low sexual dysfunction, they tended to report moderate to poor quality of sexual life. Our findings support the implication that sexual rehabilitation must be provided for women with SCI soon after injury.

COPD and occupational exposures: a case-control study.

PubMed

Weinmann, Sheila; Vollmer, William M; Breen, Victor; Heumann, Michael; Hnizdo, Eva; Villnave, Jacqueline; Doney, Brent; Graziani, Monica; McBurnie, Mary Ann; Buist, A Sonia

2008-05-01

Evidence demonstrates that occupational exposures are causally linked with chronic obstructive pulmonary disease (COPD). This case-control study evaluated the association between occupational exposures and prevalent COPD based on lifetime occupational history. Cases (n = 388) aged 45 years and older with COPD were compared with controls (n = 356), frequency matched on age, sex, and cigarette smoking history. Odds ratios for exposure to each of eight occupational hazard categories and three composite measures of exposure were computed using logistic regression. RESULTSOccupational exposures most strongly associated with COPD were diesel exhaust, irritant gases and vapors, mineral dust, and metal dust. The composite measures describing aggregate exposure to gases, vapors, solvents, or sensitizers (GVSS) and aggregate exposure to dust, GVSS, or diesel exhaust were also associated with COPD. In the small group of never-smokers, a similar pattern was evident. These population-based findings add to the literature linking occupational exposures to COPD.

Does iodine excess lead to hypothyroidism? Evidence from a case-control study in India.

PubMed

Kotwal, Atul; Kotwal, Jyoti; Prakash, Rajat; Kotwal, Narendra

2015-08-01

Iodine deficiency disorders have been known to mankind since antiquity and various researchers elucidated the role of iodine in its causation. However, recent evidence shows that the entire control program ignored multi-causality and association of increased iodine intake with hypothyroidism. This study was conducted to assess differences of iodine intake as measured by urinary iodine excretion (UIE) between cases of hypothyroidism and healthy controls. A case-control study was conducted with three groups (cases, hospital controls and community controls) in two cities of India. Patients with overt hypothyroidism were cases (n = 150) and were compared with age, sex and socioeconomic status-matched hospital (n = 154) and community (n = 488) controls. Thyroid function tests (T3, T4, TSH) were used as diagnostic and inclusion criteria. TPOAb and UIE estimation were carried out for all study participants. Mean values of TPOAb and UIE were higher in cases as compared to hospital controls as well as community controls (p <0.05). With a cut off of 34 IU/mL for TPOAb, more cases had an anti-TPO level >34 as compared to hospital controls (p <0.001) as well as community controls (p <0.001); OR, 0.06 (95% CI, 0.03, 0.12) and 0.08 (0.05, 0.12), respectively. For UIE cut-off of 300 μg/L, more cases than hospital controls (p = 0.090) and community controls (p = 0.001) had higher levels; OR, 0.671, (0.422, 1.066) and 0.509, (0.348, 0.744), respectively. The study has clearly shown that cases of hypothyroidism are associated with excess iodine intake. Cohort studies to generate further evidence and an eco-social epidemiological approach have been suggested as the way forward. Copyright © 2015 IMSS. Published by Elsevier Inc. All rights reserved.

A case-control study of domestic kitchen microbiology and sporadic Salmonella infection.

PubMed

Parry, S M; Slader, J; Humphrey, T; Holmes, B; Guildea, Z; Palmer, S R

2005-10-01

The microbiology of domestic kitchens in the homes of subjects who had suffered sporadic Salmonella infection (cases) was compared with control domestic kitchens. Case and control dishcloths and refrigerator swabs were examined for the presence of Salmonella spp., total Enterobacteriaceae counts and total aerobic colony counts. Salmonella spp. were isolated from both case and control dishcloths and refrigerators but there were no significant differences between the two groups. Colony counts were similar in case and control dishcloths and refrigerator swabs. There was no relationship between the total counts and presence of Salmonella . There was no evidence that cases of Salmonella infection were more likely to have kitchens which were contaminated with these bacteria or have higher bacterial counts than controls. Total bacterial counts were poor indicators of Salmonella contamination of the domestic kitchen environment. Further factors which could not be identified by a study of this design may increase risk of Salmonella food poisoning. These factors may include individual susceptibility of the patient. Alternatively, sporadic cases of Salmonella food poisoning may arise from food prepared outside the home.

Acrylamide and glycidamide hemoglobin adducts and epithelial ovarian cancer: a nested case-control study in non-smoking postmenopausal women from the EPIC cohort

PubMed Central

Obón-Santacana, Mireia; Lujan-Barroso, Leila; Travis, Ruth C.; Freisling, Heinz; Ferrari, Pietro; Severi, Gianluca; Baglietto, Laura; Boutron-Ruault, Marie-Christine; Fortner, Renée T.; Ose, Jennifer; Boeing, Heiner; Menéndez, Virginia; Sánchez-Cantalejo, Emilio; Chamosa, Saioa; Huerta Castaño, José María; Ardanaz, Eva; Khaw, Kay-Tee; Wareham, Nick; Merritt, Melissa A.; Gunter, Marc J.; Trichopoulou, Antonia; Papatesta, Eleni-Maria; Klinaki, Eleni; Saieva, Calogero; Tagliabue, Giovanna; Tumino, Rosario; Sacerdote, Carlotta; Mattiello, Amalia; Bueno-de-Mesquita, H.B.; Peeters, Petra H.; Onland-Moret, N. Charlotte; Idahl, Annika; Lundin, Eva; Weiderpass, Elisabete; Vesper, Hubert W.; Riboli, Elio; Duell, Eric J

2015-01-01

Background Acrylamide was classified as ‘probably carcinogenic to humans (group 2A)’ by the International Agency for Research on Cancer. Epithelial ovarian cancer (EOC) is the fourth cause of cancer mortality in women. Five epidemiological studies have evaluated the association between EOC risk and dietary acrylamide intake assessed using food frequency questionnaires, and one nested case-control study evaluated hemoglobin adducts of acrylamide (HbAA) and its metabolite glycidamide (HbGA) and EOC risk; the results of these studies were inconsistent. Methods A nested case-control study in non-smoking postmenopausal women (334 cases, 417 controls) was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Unconditional logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association between HbAA, HbGA, HbAA+HbGA, and HbGA/HbAA and EOC and invasive serous EOC risk. Results No overall associations were observed between biomarkers of acrylamide exposure analyzed in quintiles and EOC risk; however, positive associations were observed between some middle quintiles of HbGA and HbAA+HbGA. Elevated but non-statistically significant ORs for serous EOC were observed for HbGA and HbAA+HbGA (ORQ5vsQ1:1.91, 95%CI:0.96-3.81 and ORQ5vsQ1:1.90, 95%CI:0.94-3.83, respectively); however, no linear dose-response trends were observed. Conclusion This EPIC nested case-control study failed to observe a clear association between biomarkers of acrylamide exposure and the risk of EOC or invasive serous EOC. Impact It is unlikely that dietary acrylamide exposure increases ovarian cancer risk; however, additional studies with larger sample size should be performed to exclude any possible association with EOC risk. PMID:26376083

Rethinking sources of representative controls for the conduct of case-control studies in minority populations.

PubMed

Bandera, Elisa V; Chandran, Urmila; Zirpoli, Gary; McCann, Susan E; Ciupak, Gregory; Ambrosone, Christine B

2013-05-31

Recruitment of controls remains a challenge in case-control studies and particularly in studies involving minority populations. We compared characteristics of controls recruited through random digit dialing (RDD) to those of community controls enrolled through churches, health events and other outreach sources among women of African ancestry (AA) participating in the Women's Circle of Health Study, a case-control study of breast cancer. Odds ratios and 95% confidence intervals were also computed using unconditional logistic regression to evaluate the impact of including the community controls for selected variables relevant to breast cancer and for which there were significant differences in distribution between the two control groups. Compared to community controls (n=347), RDD controls (n=207) had more years of education and higher income, lower body mass index, were more likely to have private insurance, and less likely to be single. While the percentage of nulliparous women in the two groups was similar, community controls tended to have more children, have their first child at a younger age, and were less likely to breastfeed their children. Dietary intake was similar in the two groups. Compared to census data, the combination of RDD and community controls seems to be more representative of the general population than RDD controls alone. Furthermore, the inclusion of the community group had little impact on the magnitude of risk estimates for most variables, while enhancing statistical power. Community-based recruitment was found to be an efficient and feasible method to recruit AA controls.

Statin use and fatal prostate cancer: a matched case-control study.

PubMed

Marcella, Stephen W; David, Alice; Ohman-Strickland, Pamela A; Carson, Jeffery; Rhoads, George G

2012-08-15

Statins are some of the most commonly prescribed medications in medical practice, and prostate cancer is the most common malignancy among men. Although there has been no consistent evidence that statins affect cancer incidence, including prostate cancer, several reports suggest they may decrease the rate of advanced prostate cancer. However, no study to date has specifically examined statin use and prostate cancer mortality. The authors conducted this population-based case-control investigation to examine this association. This was a matched case-control study. Cases were residents of New Jersey ages 55 to 79 years who died from prostate cancer between 1997 and 2000. The cases were matched individually to population-based controls by 5-year age group and race. Medication data were obtained identically for cases and controls from blinded medical chart review. Conditional logistic regression was used to adjust for confounders. In total, 718 cases were identified, and cooperation was obtained from 77% of their spouses (N = 553). After a review of medical records, 387 men were eligible, and 380 were matched to a control. The unadjusted odds ratio was 0.49 (95% confidence interval, 0.34-0.70) and decreased to 0.37 (P < .0001) after adjusting for education, waist size, body mass index, comorbidities, and antihypertensive medication. There was little difference between lipophilic and hydrophilic statins, but more risk reduction was noted for high-potency statins (73%; P < .0001) compared with low-potency statins (31%; P = .32). Statin use was associated with substantial protection against prostate cancer death, adding to the epidemiologic evidence for an inhibitory effect on prostate cancer. Copyright © 2011 American Cancer Society.

Blood Harmane (1-methyl-9h-pyrido[3,4-b]indole) Concentrations in Essential Tremor: Repeat Observation in Cases and Controls in New York

PubMed Central

Louis, Elan D.; Jiang, Wendy; Gerbin, Marina; Viner, Amanda S.; Factor-Litvak, Pam; Zheng, Wei

2012-01-01

Essential tremor (ET) is a widespread late-life neurological disease. Genetic and environmental factors are likely to play important etiological roles. Harmane (1-methyl-9H-pyrido[3,4-b]indole) is a potent tremor-producing neurotoxin. Previously, elevated blood harmane concentrations were demonstrated in ET cases compared to controls, but these observations were all been cross-sectional, assessing each subject at only one time point. Thus, no one has ever repeat-assayed blood harmane in the same subjects twice. Whether the observed case-control difference persists at a second time point, years later, is unknown. The current goal was to re-assess a sample of our ET cases and controls to determine whether blood harmane concentration remained elevated in ET at a second time point. Blood harmane concentrations were quantified by a well-established high performance liquid chromatography method in 63 ET cases and 70 controls. A mean of approximately 6 years elapsed between the initial and this subsequent blood harmane determination. The mean log blood harmane concentration was significantly higher in cases than controls (0.30 ± 0.61 g−10/ml vs. 0.08 ± 0.55 g−10/ml), and the median value in cases was double that of controls: 0.22 g−10/ml vs. 0.11 g−10/ml. The log blood harmane concentration was highest in cases with a family history of ET. Blood harmane concentration was elevated in ET cases compared to controls when re-assessed at a second time point several years later, indicating what seems to be a stable association between this environmental toxin and ET. PMID:22757671

Blood harmane (1-methyl-9H-pyrido[3,4-b]indole) concentrations in essential tremor: repeat observation in cases and controls in New York.

PubMed

Louis, Elan D; Jiang, Wendy; Gerbin, Marina; Viner, Amanda S; Factor-Litvak, Pam; Zheng, Wei

2012-01-01

Essential tremor (ET) is a widespread late-life neurological disease. Genetic and environmental factors are likely to play important etiological roles. Harmane (1-methyl-9H-pyrido[3,4-b]indole) is a potent tremor-producing neurotoxin. Previously, elevated blood harmane concentrations were demonstrated in ET cases compared to controls, but these observations have all been cross-sectional, assessing each subject at only one time point. Thus, no one has ever repeat-assayed blood harmane in the same subjects twice. Whether the observed case-control difference persists at a second time point, years later, is unknown. The current goal was to reassess a sample of our ET cases and controls to determine whether blood harmane concentration remained elevated in ET at a second time point. Blood harmane concentrations were quantified by a well-established high-performance liquid chromatography method in 63 ET cases and 70 controls. A mean of approximately 6 yr elapsed between the initial and this subsequent blood harmane determination. The mean log blood harmane concentration was significantly higher in cases than controls (0.30 ± 0.61 g(-10)/ml versus 0.08 ± 0.55 g(-10)/ml), and the median value in cases was double that of controls: 0.22 g(-10)/ml versus 0.11 g(-10)/ml. The log blood harmane concentration was highest in cases with a family history of ET. Blood harmane concentration was elevated in ET cases compared to controls when reassessed at a second time point several years later, indicating what seems to be a stable association between this environmental toxin and ET.

Social capital and adverse treatment outcomes of tuberculosis: a case-control study.

PubMed

Deshmukh, P R; Mundra, A; Dawale, A

2017-08-01

'Social capital' refers to social norms, relationships, networks and values that affect the functioning and development of society. Social capital influences health positively, but its role in the treatment outcomes of tuberculosis (TB) is not known. To study the role of social capital in determining adverse TB treatment outcomes. Of 516 patients registered under the Revised National Tuberculosis Control Programme in 2014 in Wardha Tuberculosis Unit, Wardha, India, we included 88 patients with adverse treatment outcomes as cases and 187 controls from among those without adverse outcomes. Multiple logistic regression was used to compare standardised Z-scores. A greater proportion of controls than cases belonged to higher quartiles of social capital and its domains than cases, and the mean standardised Z-score was also consistently higher among controls than cases. Respectively 47% and 15% of cases and controls were in the poorest quartile of social capital, whereas respectively 10% and 33% of cases and controls were in the richest quartile. Each unit increase in Z-score of overall social capital reduced the odds of adverse treatment outcomes by 63.1%. Appropriate interventions for building social capital for TB patients and linking them with the programme would improve programme performance.

Occupation and bladder cancer: a population-based, case-control study in Iowa.

PubMed

Zheng, Tongzhang; Cantor, Kenneth P; Zhang, Yawei; Lynch, Charles F

2002-07-01

While considerable efforts have been made to investigate the role of occupation and industry in the risk of bladder cancer, many reported associations have not been consistent, and strong evidence of increased risk is apparent for few occupational groups. To further examine the issue, a large, population-based, case-control study was conducted in the state of Iowa among both men and women. A total of 1452 incident bladder cancer cases and 2434 controls were included in the study. Occupational history was collected from respondents for each job held for 5 years or longer since age 16. Among men, excess risk was observed for industries including plumbing, heating, and air conditioning (odds ratio [OR], = 2.2; 95% confidence interval [CI], 1.0 to 5.0); rubber and plastic products (OR = 3.1; 95% CI, 1.2 to 8.5), motor vehicle parts and supplies (OR = 4.5; 95% CI, 1.2 to 16.5), and occupations including supervisors for transportation and material moving (OR = 6.5; 95% CI, 1.4 to 29.9), material-moving-equipment operators (OR = 1.9; 95% CI, 1.0 to 3.6), automobile mechanics (OR = 1.6; 95% CI, 1.0 to 2.6), painters (OR = 2.7; 95% CI, 1.0 to 7.7), and metal- and plastic-working machine operators (OR = 2.0; 95% CI, 1.1 to 3.4). Among women, significant excess risk was observed for secondary school teachers and record clerks. Housekeepers and butlers and workers in laundering and dry cleaning were also at increased risk. In conclusion, these results suggest that occupational exposures may play a significant role in the risk of bladder cancer.

Pain Sensitivity Risk Factors for Chronic TMD: Descriptive Data and Empirically Identified Domains from the OPPERA Case Control Study

PubMed Central

Greenspan, Joel D.; Slade, Gary D.; Bair, Eric; Dubner, Ronald; Fillingim, Roger B.; Ohrbach, Richard; Knott, Charlie; Mulkey, Flora; Rothwell, Rebecca; Maixner, William

2011-01-01

Many studies report that people with temporomandibular disorders (TMD) are more sensitive to experimental pain stimuli than TMD-free controls. Such differences in sensitivity are observed in remote body sites as well as in the orofacial region, suggesting a generalized upregulation of nociceptive processing in TMD cases. This large case-control study of 185 adults with TMD and 1,633 TMD-free controls measured sensitivity to painful pressure, mechanical cutaneous, and heat stimuli, using multiple testing protocols. Based on an unprecedented 36 experimental pain measures, 28 showed statistically significantly greater pain sensitivity in TMD cases than controls. The largest effects were seen for pressure pain thresholds at multiple body sites and cutaneous mechanical pain threshold. The other mechanical cutaneous pain measures and many of the heat pain measures showed significant differences, but with lesser effect sizes. Principal component analysis (PCA) of the pain measures derived from 1,633 controls identified five components labeled: (1) heat pain ratings, (2) heat pain aftersensations and tolerance, (3) mechanical cutaneous pain sensitivity, (4) pressure pain thresholds, and (5) heat pain temporal summation. These results demonstrate that, compared to TMD-free controls, chronic TMD cases are more sensitive to many experimental noxious stimuli at extra-cranial body sites, and provides for the first time the ability to directly compare the case-control effect sizes of a wide range of pain sensitivity measures. PMID:22074753

Occupational risk factors for testicular cancer: a registry-based case-control study in Rhineland Palatinate – Germany

PubMed Central

Yousif, Lamyaa; Hammer, Gaël P.; Emrich, Katharina; Blettner, Maria; Zeeb, Hajo

2013-01-01

Objectives: Testicular cancer affects mainly men below the age of 50. An association with occupation and social status has been suggested but risk factors are not well understood. A registry-based case-control study focusing on occupation was performed in Germany. Methods: All 348 testicular cancer cases with available gainful occupational information registered between 2000 and 2005; as well as 564 suitable controls (from a pool of other cancers) were drawn from the Cancer Registry of Rhineland-Palatinate. Unconditional logistic regression was used to compute odds ratios (OR) and associated 95% confidence intervals (CI). Results: Slightly elevated OR were observed for technicians and related professionals (OR 1.62, 95% CI 1.00–2.63) and for clerical support workers (OR 1.71, 95% CI 1.14–2.56). This increase was highest in the age group 20–50 for technicians (OR 2.02, 95% CI 1.23–3.33) and clerks (OR 2.00, 95% CI 1.30–3.09), respectively. An association with testicular cancer was observed for no other occupation. Conclusion: An increased risk of testicular cancer was observed for technicians and related professionals and clerical support workers. This could be related to socioeconomic status or sedentary life style, two factors that were identified in previous studies. While the feasibility of a purely registry-based study was shown, missing occupational data and the choice of cancer controls represent challenges to the validity of this approach. PMID:24265602

Design, methodological issues and participation in a multiple sclerosis case-control study.

PubMed

Williamson, D M; Marrie, R A; Ashley-Koch, A; Schiffer, R; Trottier, J; Wagner, L

2012-09-01

This study was conducted to determine whether the risk of developing multiple sclerosis (MS) was associated with certain environmental exposures or genetic factors previously reported to influence MS risk. This paper describes the methodological issues, study design and characteristics of the study population. Individuals with definite MS were identified from a prevalence study conducted in three geographic areas. The target number of cases was not reached, so an additional study area was added. Identifying clinic controls was inefficient, so controls were recruited using random digit dialing. All study participants completed a detailed questionnaire regarding environmental exposures using computer-assisted telephone interviewing, and blood was collected for genetic analysis. In total, 276 cases and 590 controls participated, but participation rates were low, ranging from 28.4% to 38.9%. Only one-third (33.6%) of individuals identified in the prevalence study agreed to participate in the case-control study. Cases were more likely to be non-Hispanic white and older than their source populations as identified in the preceding prevalence study (P < 0.05). Most participants provided a blood sample for genotyping (91%; n = 789). Epidemiological studies play a key role in identifying genetic and environmental factors that are associated with complex diseases like MS. Methodological issues arise in every study, and investigators need to be able to detect, respond to and correct problems in a timely and scientifically valid manner. © 2011 John Wiley & Sons A/S.

Serum concentrations of fatty acids and colorectal adenoma risk: a case-control study in Japan.

PubMed

Ghadimi, Reza; Kuriki, Kiyonori; Tsuge, Shinji; Takeda, Emiru; Imaeda, Nahomi; Suzuki, Sadao; Sawai, Asuka; Takekuma, Kiyoshi; Hosono, Akihiro; Tokudome, Yuko; Goto, Chiho; Esfandiary, Imaneh; Nomura, Hisashi; Tokudome, Shinkan

2008-01-01

Epidemiologic studies of n-3 fatty acids (FAs) and risk of colorectal cancer have generated inconsistent results, and relations with precursor colorectal adenomas (CRA) have not been evaluated in detail. We here focused on possible associations of serum FAs with CRA in the Japanese population. We conducted a case-control study of 203 asymptomatic CRA cases (148 men, 55 women) and 179 healthy controls (67 men, 112 women) during 1997-2003 in Nagoya, Japan. Baseline information was obtained using a lifestyle questionnaire and serum FA levels were measured by gas chromatography. A non-significant inverse association with CRA was observed for eicosapentaenoic acid (EPA) among women. Moreover, the concentrations of docosahexaenoeic acid (DHA), a major component of n-3 highly-unsaturated FAs (HUFAs), were significantly lower in cases in both sexes. In addition, serum concentrations of total FAs, saturated FAs (SFAs) and mono-unsaturated FAs (MUFAs) had strong positive links with CRA risk. In contrast, arachidonic acid (AA) and DHA were inversely related, with 66% and 59% risk reduction, respectively. Ratios of SFAs/n-3 PUFAs and SFAs/n-3 HUFAs exhibited significant positive relations with CRA risk but there was no clear link with n-6 PUFAs/n-3 PUFAs. Our findings suggest a promoting influence of SFAs and MUFAs along with a protective effect of DHA on CRA risk. However, further research is needed to investigate the observed discrepancy with the generally accepted roles of the AA cascade in carcinogenesis.

Dietary patterns, goitrogenic food, and thyroid cancer: a case-control study in French Polynesia.

PubMed

Cléro, Énora; Doyon, Françoise; Chungue, Vaïana; Rachédi, Frédérique; Boissin, Jean-Louis; Sebbag, Joseph; Shan, Larrys; Rubino, Carole; de Vathaire, Florent

2012-01-01

French Polynesia has one of the world's highest thyroid cancer incidence rates. A case-control study among native residents of French Polynesia included 229 cases of differentiated thyroid cancer diagnosed between 1979 and 2004, and 371 population controls. Dietary patterns and goitrogenic food consumption (cabbage, cassava) were analyzed. We used a factor analysis to identify dietary patterns and a conditional logistic regression analysis to investigate the association between dietary patterns or food items and thyroid cancer risk. Two distinct dietary patterns were identified: traditional Polynesian and Western. A nonsignificant inverse association was observed between the traditional Polynesian dietary pattern and thyroid cancer risk. The Western pattern was not associated with thyroid cancer risk. Cassava consumption was significantly associated with a decreased risk of thyroid cancer. In conclusion, a traditional Polynesian dietary pattern led to a weak reduced risk of thyroid cancer in French Polynesia. The protective effect of cassava on this cancer does not seem to be substantially different from that of cabbage, which was the main goitrogenic food studied to date.

Trachoma and Relative Poverty: A Case-Control Study.

PubMed

Habtamu, Esmael; Wondie, Tariku; Aweke, Sintayehu; Tadesse, Zerihun; Zerihun, Mulat; Zewdie, Zebideru; Callahan, Kelly; Emerson, Paul M; Kuper, Hannah; Bailey, Robin L; Mabey, David C W; Rajak, Saul N; Polack, Sarah; Weiss, Helen A; Burton, Matthew J

2015-11-01

Trachoma is widely considered a disease of poverty. Although there are many epidemiological studies linking trachoma to factors normally associated with poverty, formal quantitative data linking trachoma to household economic poverty within endemic communities is very limited. Two hundred people with trachomatous trichiasis were recruited through community-based screening in Amhara Region, Ethiopia. These were individually matched by age and gender to 200 controls without trichiasis, selected randomly from the same sub-village as the case. Household economic poverty was measured through (a) A broad set of asset-based wealth indicators and relative household economic poverty determined by principal component analysis (PCA, (b) Self-rated wealth, and (c) Peer-rated wealth. Activity participation data were collected using a modified 'Stylised Activity List' developed for the World Bank's Living Standards Measurement Survey. Trichiasis cases were more likely to belong to poorer households by all measures: asset-based analysis (OR = 2.79; 95%CI: 2.06-3.78; p<0.0001), self-rated wealth (OR, 4.41, 95%CI, 2.75-7.07; p<0.0001) and peer-rated wealth (OR, 8.22, 95% CI, 4.59-14.72; p<0.0001). Cases had less access to latrines (57% v 76.5%, p = <0.0001) and higher person-to-room density (4.0 v 3.31; P = 0.0204) than the controls. Compared to controls, cases were significantly less likely to participate in economically productive activities regardless of visual impairment and other health problems, more likely to report difficulty in performing activities and more likely to receive assistance in performing productive activities. This study demonstrated a strong association between trachomatous trichiasis and relative poverty, suggesting a bidirectional causative relationship possibly may exist between poverty and trachoma. Implementation of the full SAFE strategy in the context of general improvements might lead to a virtuous cycle of improving health and wealth. Trachoma is a

Secondhand Smoking and the Risk of Esophageal Squamous Cell Carcinoma in a High Incidence Region, Kashmir, India: A Case-control-observational Study.

PubMed

Rafiq, Rumaisa; Shah, Idrees Ayoub; Bhat, Gulzar Ahmad; Lone, Mohd Maqbool; Islami, Farhad; Boffetta, Paolo; Dar, Nazir Ahmad

2016-01-01

Studies have associated secondhand smoking (SHS) with cancers of the lung, larynx, and pharynx. Only a few studies have examined the association between SHS and esophageal squamous cell carcinoma (ESCC) and the findings are inconclusive. We aimed to investigate the association between SHS and risk of ESCC in a case-control study in Kashmir, where the incidence of ESCC is high. We recruited 703 histopathologically confirmed ESCC cases and 1664 hospital-based controls individually matched to the cases for age, sex, and district of residence. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using conditional logistic regression models. Among never-tobacco users, the ORs for the association between SHS and ESCC risk were above unity with ever exposure to SHS (OR = 1.32; 95% CI, 0.43-4.02) and exposure to SHS for > 14 h/wk (median value) (OR = 2.69; 95% CI, 0.75-20.65). In the analysis of data from all participants, the OR (95% CI) for the association between SHS and ESCC was (OR = 1.02; 95% CI, 0.53-1.93) for SHS ≤ 14 h/wk and (OR = 1.91; 95% CI, 0.75-4.89) for SHS >14 h/wk in the models adjusted for tobacco use and several other potential confounding factors. We found an indication of increased risk of ESCC associated with exposure to SHS. Studies with larger numbers of SHS-exposed never tobacco users are required to further examine this association.

Field-based random sampling without a sampling frame: control selection for a case-control study in rural Africa.

PubMed

Crampin, A C; Mwinuka, V; Malema, S S; Glynn, J R; Fine, P E

2001-01-01

Selection bias, particularly of controls, is common in case-control studies and may materially affect the results. Methods of control selection should be tailored both for the risk factors and disease under investigation and for the population being studied. We present here a control selection method devised for a case-control study of tuberculosis in rural Africa (Karonga, northern Malawi) that selects an age/sex frequency-matched random sample of the population, with a geographical distribution in proportion to the population density. We also present an audit of the selection process, and discuss the potential of this method in other settings.

Power and sample size for multivariate logistic modeling of unmatched case-control studies.

PubMed

Gail, Mitchell H; Haneuse, Sebastien

2017-01-01

Sample size calculations are needed to design and assess the feasibility of case-control studies. Although such calculations are readily available for simple case-control designs and univariate analyses, there is limited theory and software for multivariate unconditional logistic analysis of case-control data. Here we outline the theory needed to detect scalar exposure effects or scalar interactions while controlling for other covariates in logistic regression. Both analytical and simulation methods are presented, together with links to the corresponding software.

Case-control study of urinary bladder cancer in metropolitan Nagoya.

PubMed

Ohno, Y; Aoki, K; Obata, K; Morrison, A S

1985-12-01

We conducted a population-based case-control study of patients with bladder cancer and of controls drawn randomly from the general population of Metropolitan Nagoya and interviewed both groups. The incidence rates of bladder cancer were 2.42 and 7.05/100,000 for females and males, respectively. The analysis, based on 293 patients and 589 controls who were frequency matched for age, sex, and residence, provided the following major findings. Age-adjusted relative risks of 1.89 (1.15-3.10) and 3.53 (1.71-7.27) were found in male and female cigarette smokers, respectively. Significant relative risk was also found in males who drank cocoa. Elevated risk with a dose-response relationship was observed among women who used hair dye and who smoke, but this risk was insignificant, with the disappearance of a dose-response relationship, when it was adjusted for smoking. Age- and smoking-adjusted relative risk of coffee drinking was insignificant with no dose-response relationship. Relative risk of artificial sweetener use was below 1 with adjustment for age and smoking. Intake of alcoholic beverages and cola was insignificantly associated. Reduced risk of significance was suggested for the intake of black tea and matcha (powdered green tea) in females and of fruit juice in males.

Caries Experience in Children with and without Molar-Incisor Hypomineralisation: A Case-Control Study.

PubMed

Grossi, Juliana de Aguiar; Cabral, Renata Nunes; Leal, Soraya Coelho

2017-01-01

The aim of this study was to compare the caries experience of children with and without molar-incisor hypomineralisation (MIH). A case-control study was designed in which 130 children aged between 7 and 13 years with MIH (cases) were matched with 130 children without the condition (controls) according to age, sex, and school. Dental caries and MIH were assessed using the Caries Assessment Spectrum and Treatment (CAST) and European Academy of Paediatric Dentistry (EAPD) criteria, respectively, by three examiners. CAST was converted into DMFT/dmft; the Kruskal-Wallis test was performed to analyse whether dmft/DMFT was influenced by the severity of MIH. Associations between MIH and dental caries were analysed at child and tooth levels: between and within subjects, respectively. To correlate MIH severity and the occurrence of dental caries, the Cochran-Armitage test was used. The mean age of the children was 9.63 ± 1.29 years. The mean dmft for cases was 1.23 ± 1.99 and for controls 1.71 ± 2.22 (p > 0.05). For the DMFT, the mean scores for cases and controls were 0.45 ± 0.90 and 0.07 ± 0.25, respectively (p < 0.001). The between-subject analysis showed no difference in relation to enamel carious lesions; however, the prevalence of dentine carious lesions was significantly higher in children with MIH than in those without the condition. The same pattern was seen for the within-subject analysis. It was observed that the increase in MIH severity resulted in more teeth being affected by dentine carious lesions (p = 0.0003). Children with MIH presented a higher experience of caries in the permanent dentition than those without the condition. MIH was considered a risk factor for caries development. © 2017 S. Karger AG, Basel.

Statin Use and Fatal Prostate Cancer: A Matched Case-Control Study

PubMed Central

Marcella, Stephen W.; David, Alice; Ohman-Strickland, Pamela A.; Carson, Jeffery; Rhoads, George G.

2015-01-01

Background Statins are one of the most commonly prescribed medications in medical practice and prostate cancer is the most common male malignancy. While there has been no consistent evidence that statins affect cancer incidence, including prostate cancer, several reports suggest they may decrease the rate of advanced prostate cancer. However, no study has examined statin use and prostate cancer mortality specifically. We report here a population-based case-control investigation that examines this association. Methods We conducted a matched case-control study. Cases were residents of New Jersey ages 55 – 79 who died from prostate cancer between 1997–2000. We individually matched population-based controls by five-year age-group and race. Medication data were obtained identically for cases and controls from blinded medical chart review. We used conditional logistic regression to adjust for confounders. Results We identified 718 cases and obtained cooperation from 77% of their spouses (N=553). After review of medical records, 387 were eligible and 380 were matched to a control. The unadjusted odds ratio was 0.49 (95% CI, 0.34–0.70) which decreased to 0.37 (p<0.0001) after adjustment for education, waist size, BMI, comorbidities, and anti-hypertensive medication. There was little difference between lipophilic and hydrophilic statins but more risk reduction was noted for hi-potency statins (73%, p<0.0001) as compared to low-potency statins (31%, p=0.32). Conclusion Statin use is associated with substantial protection against prostate cancer death, adding to the epidemiologic evidence for an inhibitory effect on prostate cancer. PMID:22180145

Air Pollution and Pulmonary Tuberculosis: A Nested Case-Control Study among Members of a Northern California Health Plan.

PubMed

Smith, Geneé S; Van Den Eeden, Stephen K; Garcia, Cynthia; Shan, Jun; Baxter, Roger; Herring, Amy H; Richardson, David B; Van Rie, Annelies; Emch, Michael; Gammon, Marilie D

2016-06-01

Ecologic analyses, case-case comparisons, and animal experiments suggest positive associations between air pollution and tuberculosis. We evaluated this hypothesis in a large sample, which yielded results that are applicable to the general population. We conducted a case-control study nested within a cohort of Kaiser Permanente of Northern California members. All active pulmonary tuberculosis (TB) cases newly diagnosed between 1996 and 2010 (n = 2,309) were matched to two controls (n = 4,604) by age, sex, and race/ethnicity on the index date corresponding with the case diagnosis date. Average individual-level concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5) and 10 μm (PM10) for 2 years before diagnosis/entry into the study were estimated using measurements from the California Air Resources Board monitor closest to the participant's residence. In single-pollutant adjusted conditional logistic regression models, the pulmonary TB odds ratios (95% confidence intervals) for the highest quintile (vs. lowest) were 1.50 (95% CI: 1.15, 1.95) for CO and 1.42 (95% CI: 1.10, 1.84) for NO2. Corresponding estimates were higher among never [1.68 (95% CI: 1.26, 2.24)] than ever [1.19 (95% CI: 0.74, 1.92)] smokers for CO. In contrast, for NO2, estimates were higher among ever [1.81 (95% CI: 1.13, 2.91)] than never [1.29 (95% CI: 0.97, 1.71)] smokers. O3 was inversely associated for smokers [0.66 (95% CI: 0.43, 1.02)] and never smokers [0.65 (95% CI: 0.52, 0.81)]. No other consistent patterns were observed. In this first, to our knowledge, U.S. nested case-control study on air pollution and pulmonary TB, we observed positive associations with ambient CO and NO2, which require confirmation. Smith GS, Van Den Eeden SK, Garcia C, Shan J, Baxter R, Herring AH, Richardson DB, Van Rie A, Emch M, Gammon MD. 2016. Air pollution and pulmonary tuberculosis: a nested case-control

Intravenous Immunoglobulin Therapy in Pediatric Narcolepsy: A Nonrandomized, Open-Label, Controlled, Longitudinal Observational Study

PubMed Central

Lecendreux, Michel; Berthier, Johanna; Corny, Jennifer; Bourdon, Olivier; Dossier, Claire; Delclaux, Christophe

2017-01-01

Study Objectives: Previous case reports of intravenous immunoglobulins (IVIg) in pediatric narcolepsy have shown contradictory results. Methods: This was a nonrandomized, open-label, controlled, longitudinal observational study of IVIg use in pediatric narcolepsy with retrospective data collection from medical files obtained from a single pediatric national reference center for the treatment of narcolepsy in France. Of 56 consecutively referred patients with narcolepsy, 24 received IVIg (3 infusions administered at 1-mo intervals) in addition to standard care (psychostimulants and/or anticataplectic agents), and 32 continued on standard care alone (controls). Results: For two patients in each group, medical files were unavailable. Of the 22 IVIg patients, all had cerebrospinal fluid (CSF) hypocretin ≤ 110 pg/mL and were HLA-DQB1*06:02 positive. Of the 30 control patients, 29 were HLA-DQB1*06:02 positive and of those with available CSF measurements, all 12 had hypocretin ≤ 110 pg/mL. Compared with control patients, IVIg patients had shorter disease duration, shorter latency to sleep onset, and more had received H1N1 vaccination. Mean (standard deviation) follow-up length was 2.4 (1.1) y in the IVIg group and 3.9 (1.7) y in controls. In multivariate-adjusted linear mixed-effects analyses of change from baseline in Ullanlinna Narcolepsy Scale (UNS) scores, high baseline UNS, but not IVIg treatment, was associated with a reduction in narcolepsy symptoms. On time-to-event analysis, among patients with high baseline UNS scores, control patients achieved a UNS score < 14 (indicating remission) less rapidly than IVIg patients (adjusted hazard ratio 0.18; 95% confidence interval: 95% confidence interval: 0.03, 0.95; p = 0.043). Shorter or longer disease duration did not influence treatment response in any analysis. Conclusions: Overall, narcolepsy symptoms were not significantly reduced by IVIg. However, in patients with high baseline symptoms, a subset of IVIg

Gall bladder mucoceles and their association with endocrinopathies in dogs: a retrospective case-control study.

PubMed

Mesich, M L L; Mayhew, P D; Paek, M; Holt, D E; Brown, D C

2009-12-01

To investigate the relationship between endocrinopathies and diagnosis of gall bladder mucocele in dogs via a retrospective case-control study. Records of 78 dogs with a surgical or ultrasonographic diagnosis of gall bladder mucocele were examined for the presence or absence of hyperadrenocorticism, hypothyroidism and diabetes mellitus. Two age- and breed-matched controls for each gall bladder mucocele dog (156 total control dogs) were examined for the same concurrent diseases. A matched case-control analysis was performed using conditional logistic regression. The odds of mucocele in dogs with hyperadrenocorticism were 29 times that of dogs without hyperadrenocorticism (P=0.001; 95 per cent CI 3.8, 219.9). No difference was found between dogs with and without diabetes mellitus. Although a significant association was found between gall bladder mucocele and hypothyroidism, potential observation bias was also identifi ed. Hyperadrenocorticoid dogs that were presented for acute illness with laboratory evidence of hepatobiliary disease should undergo evaluation for the presence of a biliary mucocele. Dogs diagnosed with a gall bladder mucocele should be screened for concurrent hyperadrenocorticism if clinical suspicion exists.

Breast Cancer and Modifiable Lifestyle Factors in Argentinean Women: Addressing Missing Data in a Case-Control Study

PubMed Central

Coquet, Julia Becaria; Tumas, Natalia; Osella, Alberto Ruben; Tanzi, Matteo; Franco, Isabella; Diaz, Maria Del Pilar

2016-01-01

A number of studies have evidenced the effect of modifiable lifestyle factors such as diet, breastfeeding and nutritional status on breast cancer risk. However, none have addressed the missing data problem in nutritional epidemiologic research in South America. Missing data is a frequent problem in breast cancer studies and epidemiological settings in general. Estimates of effect obtained from these studies may be biased, if no appropriate method for handling missing data is applied. We performed Multiple Imputation for missing values on covariates in a breast cancer case-control study of Córdoba (Argentina) to optimize risk estimates. Data was obtained from a breast cancer case control study from 2008 to 2015 (318 cases, 526 controls). Complete case analysis and multiple imputation using chained equations were the methods applied to estimate the effects of a Traditional dietary pattern and other recognized factors associated with breast cancer. Physical activity and socioeconomic status were imputed. Logistic regression models were performed. When complete case analysis was performed only 31% of women were considered. Although a positive association of Traditional dietary pattern and breast cancer was observed from both approaches (complete case analysis OR=1.3, 95%CI=1.0-1.7; multiple imputation OR=1.4, 95%CI=1.2-1.7), effects of other covariates, like BMI and breastfeeding, were only identified when multiple imputation was considered. A Traditional dietary pattern, BMI and breastfeeding are associated with the occurrence of breast cancer in this Argentinean population when multiple imputation is appropriately performed. Multiple Imputation is suggested in Latin America’s epidemiologic studies to optimize effect estimates in the future. PMID:27892664

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

PubMed

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

2018-05-01

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

Hyperthyroidism association with SLE, lessons from real-life data--A case-control study.

PubMed

Watad, Abdulla; Cohen, Arnon D; Comaneshter, Doron; Tekes-Manova, Dorit; Amital, Howard

2016-01-01

Despite the frequently encountered association between thyroid disease and systemic lupus erythematosus (SLE) is well known, it is of surprise that only several reports compromised of small population size support this observation. To investigate the association of comorbid SLE and hyperthyroidism. Using the database of the largest health maintenance organization (HMO) in Israel, the Clalit Health Services, we searched for the co-existence of SLE and hyperthyroidism. Patients with SLE were compared with age- and sex-matched controls regarding the prevalence of hyperthyroidism in a case-control study. Chi-square and t-tests were used for univariate analysis and a logistic regression model was used for multivariate analysis. The study included 5018 patients with SLE and 25,090 age- and sex- matched controls. The prevalence of hyperthyroidism in patients with SLE was increased compared with the prevalence in controls (2.59% and 0.91%, respectively, p < 0.001). In a multivariate analysis, SLE was associated with hyperthyroidism (odds ratio 2.52, 95% confidence interval 2.028-3.137). Patients with SLE have a greater prevalence of hyperthyroidism than matched controls. Therefore, physicians treating patients with SLE should be aware of this possibility of this thyroid dysfunction.

Hygiene behaviour and hospitalized severe childhood diarrhoea: a case-control study.

PubMed

Baltazar, J C; Tiglao, T V; Tempongko, S B

1993-01-01

The relationship between personal and domestic hygiene behaviour and hospitalized childhood diarrhoea was examined in a case-control study of 356 cases and 357 controls from low-income families in metropolitan Manila. Indices of hygiene behaviour were defined for overall cleanliness, kitchen hygiene, and living conditions. Only the indices for overall cleanliness and kitchen hygiene were significantly associated with diarrhoea. An increasing excess risk of hospitalization with severe diarrhoea was noted as the ratings for standards of hygiene became lower, and this excess risk persisted even after controlling for confounding variables. The implications of our findings for the control of diarrhoeal disease are discussed.

Hygiene behaviour and hospitalized severe childhood diarrhoea: a case-control study.

PubMed Central

Baltazar, J. C.; Tiglao, T. V.; Tempongko, S. B.

1993-01-01

The relationship between personal and domestic hygiene behaviour and hospitalized childhood diarrhoea was examined in a case-control study of 356 cases and 357 controls from low-income families in metropolitan Manila. Indices of hygiene behaviour were defined for overall cleanliness, kitchen hygiene, and living conditions. Only the indices for overall cleanliness and kitchen hygiene were significantly associated with diarrhoea. An increasing excess risk of hospitalization with severe diarrhoea was noted as the ratings for standards of hygiene became lower, and this excess risk persisted even after controlling for confounding variables. The implications of our findings for the control of diarrhoeal disease are discussed. PMID:8324851

Medical and drug risk factors associated with neuroblastoma: a case-control study.

PubMed

Kramer, S; Ward, E; Meadows, A T; Malone, K E

1987-05-01

A matched case-control study of prenatal risk factors for neuroblastoma was conducted, including 104 cases diagnosed over the period 1970-79 in the Greater Delaware Valley. Significantly elevated odds ratios (ORs) were associated with maternal use of a neurally active drug during pregnancy (OR = 2.83), sex hormone exposure 3 months prior to or during pregnancy (OR = 2.25), frequent alcohol consumption during pregnancy (OR = 9.0), and maternal use of diuretic drugs during pregnancy (OR = 5.75). Significantly more case mothers than control mothers reported use of hair coloring products during pregnancy (OR = 3.0). No association was found between cigarette smoking, coffee consumption, or medical irradiation and case-control status.

Lung Cancer Risk Among Hairdressers: A Pooled Analysis of Case-Control Studies Conducted Between 1985 and 2010

PubMed Central

Olsson, Ann C.; Xu, Yiwen; Schüz, Joachim; Vlaanderen, Jelle; Kromhout, Hans; Vermeulen, Roel; Peters, Susan; Stücker, Isabelle; Guida, Florence; Brüske, Irene; Wichmann, Heinz-Erich; Consonni, Dario; Landi, Maria Teresa; Caporaso, Neil; Tse, Lap Ah; Yu, Ignatius Tak-sun; Siemiatycki, Jack; Richardson, Lesley; Mirabelli, Dario; Richiardi, Lorenzo; Simonato, Lorenzo; Gustavsson, Per; Plato, Nils; Jöckel, Karl-Heinz; Ahrens, Wolfgang; Pohlabeln, Hermann; Tardón, Adonina; Zaridze, David; Marcus, Michael W.; ‘t Mannetje, Andrea; Pearce, Neil; McLaughlin, John; Demers, Paul; Szeszenia-Dabrowska, Neonila; Lissowska, Jolanta; Rudnai, Peter; Fabianova, Eleonora; Dumitru, Rodica Stanescu; Bencko, Vladimir; Foretova, Lenka; Janout, Vladimir; Boffetta, Paolo; Fortes, Cristina; Bueno-de-Mesquita, Bas; Kendzia, Benjamin; Behrens, Thomas; Pesch, Beate; Brüning, Thomas; Straif, Kurt

2013-01-01

Increased lung cancer risks among hairdressers were observed in large registry-based cohort studies from Scandinavia, but these studies could not adjust for smoking. Our objective was to evaluate the lung cancer risk among hairdressers while adjusting for smoking and other confounders in a pooled database of 16 case-control studies conducted in Europe, Canada, China, and New Zealand between 1985 and 2010 (the Pooled Analysis of Case-Control Studies on the Joint Effects of Occupational Carcinogens in the Development of Lung Cancer). Lifetime occupational and smoking information was collected through interviews with 19,369 cases of lung cancer and 23,674 matched population or hospital controls. Overall, 170 cases and 167 controls had ever worked as hairdresser or barber. The odds ratios for lung cancer in women were 1.65 (95% confidence interval (CI): 1.16, 2.35) without adjustment for smoking and 1.12 (95% CI: 0.75, 1.68) with adjustment for smoking; however, women employed before 1954 also experienced an increased lung cancer risk after adjustment for smoking (odds ratio = 2.66, 95% CI: 1.09, 6.47). The odds ratios in male hairdressers/barbers were generally not elevated, except for an increased odds ratio for adenocarcinoma in long-term barbers (odds ratio = 2.20, 95% CI: 1.02, 4.77). Our results suggest that the increased lung cancer risks among hairdressers are due to their smoking behavior; single elevated risk estimates should be interpreted with caution and need replication in other studies. PMID:24068200

Nutrient intake and gastric cancer risk: a case-control study in Spain.

PubMed

Ramón, J M; Serra-Majem, L; Cerdó, C; Oromí, J

1993-12-01

A case-control study of dietary factors and gastric cancer was conducted between September 1986 and March 1989 in the Barcelona metropolitan area, Spain. In all 117 cases with histologically confirmed diagnosis of gastric adenocarcinoma were matched on sex, age and possession of a telephone to 234 population controls. Of the controls 188 (80.3%) were selected by random digit telephone dialing and 46 (19.7%) by neighbourhood of residence. Information about frequency and amount of consumption of 89 alimentary items was gathered by questionnaire, and cases and controls were interviewed in their homes by trained interviewers. The gastric cancer risk decreased in proportion to vitamin C intake. In multivariate analysis adjusting for major covariables, energy and vitamin A intake, the estimated odds ratio (OR) for the upper quartile of vitamin C intake was 0.3 (95% confidence interval [CI]: 0.1-0.8). After adjustment for major covariables, calories and vitamin C intake, vitamin A did not show significant association with the gastric cancer risk. Our findings are consistent with previous case-control studies and with the hypothesis that vitamin C may inhibit the intragastric nitrosation process.

A concordance index for matched case-control studies with applications in cancer risk.

PubMed

Brentnall, Adam R; Cuzick, Jack; Field, John; Duffy, Stephen W

2015-02-10

In unmatched case-control studies, the area under the receiver operating characteristic (ROC) curve (AUC) may be used to measure how well a variable discriminates between cases and controls. The AUC is sometimes used in matched case-control studies by ignoring matching, but it lacks interpretation because it is not based on an estimate of the ROC for the population of interest. We introduce an alternative measure of discrimination that is the concordance of risk factors conditional on the matching factors. Parametric and non-parametric estimators are given for different matching scenarios, and applied to real data from breast and lung cancer case-control studies. Diagnostic plots to verify the constancy of discrimination over matching factors are demonstrated. The proposed simple measure is easy to use, interpret, more efficient than unmatched AUC statistics and may be applied to compare the conditional discrimination performance of risk factors. Copyright © 2014 John Wiley & Sons, Ltd.

A concealed observational study of infection control and safe injection practices in Jordanian governmental hospitals.

PubMed

Al-Rawajfah, Omar M; Tubaishat, Ahmad

2017-10-01

The recognized international organizations on infection prevention recommend using an observational method as the gold standard procedure for assessing health care professional's compliance with standard infection control practices. However, observational studies are rarely used in Jordanian infection control studies. This study aimed to evaluate injection practices among nurses working in Jordanian governmental hospitals. A cross-sectional concealed observational design is used for this study. A convenience sampling technique was used to recruit a sample of nurses working in governmental hospitals in Jordan. Participants were unaware of the time and observer during the observation episode. A total of 384 nurses from 9 different hospitals participated in the study. A total of 835 injections events were observed, of which 73.9% were performed without handwashing, 64.5% without gloving, and 27.5% were followed by needle recapping. Handwashing rate was the lowest (18.9%) when injections were performed by beginner nurses. Subcutaneous injections were associated with the lowest rate (26.7%) of postinjection handwashing compared with other routes. This study demonstrates the need for focused and effective infection control educational programs in Jordanian hospitals. Future studies should consider exploring the whole infection control practices related to waste disposal and the roles of the infection control nurse in this process in Jordanian hospitals. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Randomized controlled trials vs. observational studies: why not just live together?

PubMed

Faraoni, David; Schaefer, Simon Thomas

2016-10-21

Randomized controlled trials (RCTs) are considered the gold standard for clinical research, thus having a high impact on clinical guidelines and our daily patients' care. However, various treatment strategies which we consider "evidence based" have never been subject to a prospective RCT, as we would rate it unethical to withheld an established treatment to individuals in an placebo controlled trial.In a recent BMC Anesthesiology publication, Trentino et al. analyzed the usefulness of observational studies in assessing benefit and risk of different transfusion strategies. The authors nicely reviewed and summarized similarities and differences, advantages and limitations, between different study types frequently used in transfusion medicine. In this interesting article, the authors conclude, that 'when comparing the results of observational studies with RCTs assessing transfusion outcomes, it is important that one consider not only the study method, but also the key elements of the study design'. Thus, in this commentary we now discuss the pro's and con's of different study types, even irrespective of transfusion medicine.

Risk factors for late onset gram-negative infections: a case-control study.

PubMed

Samanta, Srabani; Farrer, Kate; Breathnach, Aodhan; Heath, Paul T

2011-01-01

To determine the incidence, mortality and risk factors for neonatal late onset gram-negative sepsis and meningitis (LOGNS). Retrospective case-control study. Tertiary neonatal unit in London. Consecutive inborn infants with late onset (>48 h of life) invasive gram-negative infections diagnosed between 1999 and 2005. Controls were healthy infants matched for gestation and time of admission to the neonatal unit. Clinical and risk factor data. 73 cases of LOGNS were identified of which 48 were inborn and included in the study (incidence 1.85/1000 live births). Enterobacter spp. (28%), Escherichia coli (27%) and Klebsiella spp. (21%) were the most common pathogens. The majority of infants were of very low birthweight (VLBW; 79%), and cases and controls were well matched (median gestation 26 weeks). Overall case death was 27% in cases versus 13.5% in controls (p=0.08). There was no significant difference between cases and controls regarding maternal risk factors. Mechanical ventilation, total parenteral nutrition (TPN) and its duration, presence of a central venous line and its duration, use of specific antibiotics and the occurrence of necrotising enterocolitis at or before the first positive culture were all significantly associated with case status in univariate analysis. In multivariate logistic regression analysis, only duration of TPN at or before first positive blood culture remained independently associated with LOGNS (p<0.001). LOGNS occurs predominantly in VLBW infants. When the influence of gestational age is accounted for, the only independent risk factor found for late onset gram-negative neonatal infections is the duration of TPN.

UK case control study of brain tumours in children, teenagers and young adults: a pilot study.

PubMed

Feltbower, Richard G; Fleming, Sarah J; Picton, Susan V; Alston, Robert D; Morgan, Diana; Achilles, Janice; McKinney, Patricia A; Birch, Jillian M

2014-01-08

Tumours of the central nervous system are the second most common group of childhood cancers in 0-14 year olds (24% of total cancers) and represent a major diagnostic group in 15-24 year olds. The pilot case-control study aimed to establish methodologies for a future comprehensive aetiological investigation among children and young adults. Eligible cases were newly diagnosed with an intracranial tumour of neuroepithelial tissue aged 0-24 years. The pilot recruited patients through Leeds and Manchester Principal Treatment Centres. Controls were drawn from general practice lists. Controls were frequency matched by age and gender. We interviewed 49 cases and 78 controls comprising 85% of the target sample size. Response rates were 52% for cases and 32% for controls. Completion of the questionnaire was successful, with a very small proportion of missing data being reported (5-10%). The age distribution of cases and controls was similar with around three-quarters of interviewed subjects aged 0-14. Half of cases and almost two-thirds of controls reported using a mobile phone with the majority starting between 10-14 years of age. Prevalence of breastfeeding was lower in cases than controls (Odds Ratio 0.4; 95% CI 0.2-1.2), whilst cases were more likely to be delivered by caesarean section (OR 1.6; 95% CI 0.6-4.4). Cases were significantly more likely to have a birthweight > 3.5 kg compared to controls. Cases were also more likely to come from a family with 3 or more siblings than controls (OR 3.0; 95% CI 0.7-13.6). The majority of participants (>80%) were in favour of taking either blood or saliva to aid molecular epidemiological research. Successful methods were established for identifying and recruiting a high proportion of case subjects, exploiting strong links with the clinical teams at the treatment centres. Control procedures proved more difficult to implement. However, working closely with national clinical and professional research networks will enable improved

Lung cancer and socioeconomic status in a pooled analysis of case-control studies

PubMed Central

Hovanec, Jan; Siemiatycki, Jack; Conway, David I.; Olsson, Ann; Stücker, Isabelle; Guida, Florence; Jöckel, Karl-Heinz; Pohlabeln, Hermann; Ahrens, Wolfgang; Brüske, Irene; Wichmann, Heinz-Erich; Gustavsson, Per; Consonni, Dario; Merletti, Franco; Richiardi, Lorenzo; Simonato, Lorenzo; Fortes, Cristina; Parent, Marie-Elise; McLaughlin, John; Demers, Paul; Landi, Maria Teresa; Caporaso, Neil; Tardón, Adonina; Zaridze, David; Szeszenia-Dabrowska, Neonila; Rudnai, Peter; Lissowska, Jolanta; Fabianova, Eleonora; Field, John; Dumitru, Rodica Stanescu; Bencko, Vladimir; Foretova, Lenka; Janout, Vladimir; Kromhout, Hans; Vermeulen, Roel; Boffetta, Paolo; Straif, Kurt; Schüz, Joachim; Kendzia, Benjamin; Pesch, Beate; Brüning, Thomas; Behrens, Thomas

2018-01-01

Background An association between low socioeconomic status (SES) and lung cancer has been observed in several studies, but often without adequate control for smoking behavior. We studied the association between lung cancer and occupationally derived SES, using data from the international pooled SYNERGY study. Methods Twelve case-control studies from Europe and Canada were included in the analysis. Based on occupational histories of study participants we measured SES using the International Socio-Economic Index of Occupational Status (ISEI) and the European Socio-economic Classification (ESeC). We divided the ISEI range into categories, using various criteria. Stratifying by gender, we calculated odds ratios (OR) and 95% confidence intervals (CI) by unconditional logistic regression, adjusting for age, study, and smoking behavior. We conducted analyses by histological subtypes of lung cancer and subgroup analyses by study region, birth cohort, education and occupational exposure to known lung carcinogens. Results The analysis dataset included 17,021 cases and 20,885 controls. There was a strong elevated OR between lung cancer and low SES, which was attenuated substantially after adjustment for smoking, however a social gradient persisted. SES differences in lung cancer risk were higher among men (lowest vs. highest SES category: ISEI OR 1.84 (95% CI 1.61–2.09); ESeC OR 1.53 (95% CI 1.44–1.63)), than among women (lowest vs. highest SES category: ISEI OR 1.54 (95% CI 1.20–1.98); ESeC OR 1.34 (95% CI 1.19–1.52)). Conclusion SES remained a risk factor for lung cancer after adjustment for smoking behavior. PMID:29462211

Birth outcomes of cases with conotruncal defects of heart - a population-based case-control study.

PubMed

Vereczkey, Attila; Kósa, Zsolt; Csáky-Szunyogh, Melinda; Gerencsér, Balázs; Czeizel, Andrew E

2015-03-01

The aim of this study was to evaluate the birth outcomes of cases with four types of conotruncal defects (CTDs), i.e. common truncus, transposition of great arteries, tetralogy of Fallot and double-outlet right ventricle. Birth outcomes of 597 live-born cases with CTD and 38,151 population controls without any defects were compared in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities completed by socio-demographic variables of their mothers. There was a male excess in cases with CTD (56.8%) with the same mean gestational age (39.4 versus 39.4 weeks) and preterm birth rate (8.2 versus 9.2%), but their mean birth weight was smaller (3077 versus 3276 g) with a high rate of low birthweight (14.6 versus 5.7%) compared to the birth outcomes of population controls. These data indicate intrauterine growth restriction of fetuses affected with transposition of great arteries, tetralogy of Fallot and double-outlet right ventricle particularly in females, while there were a shorter mean gestational age and smaller mean birth weigh in cases with common truncus. In general CTD, except common truncus, had no effect for gestational age but associated with a high risk for intrauterine fetal growth restriction particularly in female cases.

Cannabis use and risk of lung cancer: a case-control study.

PubMed

Aldington, S; Harwood, M; Cox, B; Weatherall, M; Beckert, L; Hansell, A; Pritchard, A; Robinson, G; Beasley, R

2008-02-01

The aim of the present study was to determine the risk of lung cancer associated with cannabis smoking. A case-control study of lung cancer in adults Cases were identified from the New Zealand Cancer Registry and hospital databases. Controls were randomly selected from the electoral roll, with frequency matching to cases in 5-yr age groups and district health boards. Interviewer-administered questionnaires were used to assess possible risk factors, including cannabis use. The relative risk of lung cancer associated with cannabis smoking was estimated by logistic regression. In total, 79 cases of lung cancer and 324 controls were included in the study. The risk of lung cancer increased 8% (95% confidence interval (CI) 2-15) for each joint-yr of cannabis smoking, after adjustment for confounding variables including cigarette smoking, and 7% (95% CI 5-9) for each pack-yr of cigarette smoking, after adjustment for confounding variables including cannabis smoking. The highest tertile of cannabis use was associated with an increased risk of lung cancer (relative risk 5.7 (95% CI 1.5-21.6)), after adjustment for confounding variables including cigarette smoking. In conclusion, the results of the present study indicate that long-term cannabis use increases the risk of lung cancer in young adults.

ERAP1 variants are associated with ankylosing spondylitis in East Asian population: a new Chinese case-control study and meta-analysis of published series.

PubMed

Chen, C; Zhang, X

2015-06-01

Endoplasmic reticulum aminopeptidase 1 (ERAP1) has been confirmed to be associated with ankylosing spondylitis (AS) in Caucasian. However, whether they are associated with AS in East Asian population remains unidentified. We investigated this relationship by a new Chinese case-control study and a meta-analysis of published series. 368 cases and 460 controls were recruited in the Chinese case-control study. Genotyping was completed using the chip-based matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Allelic associations were analysed using contingency tables. In the meta-analysis, up to 2748 cases and 2774 controls from seven different studies and the new Chinese study were combined using Review Manager software version 5.1.1. Mantel-Haenszel or Inverse Variance test was used to calculate fixed or random-effects pooled ORs. In the new Chinese study, strong association with AS was observed for marker rs10050860, rs27434 and rs1065407 at P value of <0.001. Moderate association was observed for rs30187 at P value of <0.01, while no association was observed for rs27044 (P = 0.37) and rs2287987 (P = 0.23). The meta-analysis showed that rs27037 and rs30187 were strongly associated with AS (P < 0.00001). Significant association was also observed for rs27434 (P = 0.001). No association was shown for rs27044 (P = 0.70). We concluded that ERAP1 variants are associated with AS in East Asian population, indicating a common pathogenic mechanism for AS in East Asians and Caucasians. © 2015 John Wiley & Sons Ltd.

Risk of congenital anomalies around a municipal solid waste incinerator: a GIS-based case-control study

PubMed Central

Vinceti, Marco; Malagoli, Carlotta; Fabbi, Sara; Teggi, Sergio; Rodolfi, Rossella; Garavelli, Livia; Astolfi, Gianni; Rivieri, Francesca

2009-01-01

Background Waste incineration releases into the environment toxic substances having a teratogenic potential, but little epidemiologic evidence is available on this topic. We aimed at examining the relation between exposure to the emissions from a municipal solid waste incinerator and risk of birth defects in a northern Italy community, using Geographical Information System (GIS) data to estimate exposure and a population-based case-control study design. By modelling the incinerator emissions, we defined in the GIS three areas of increasing exposure according to predicted dioxins concentrations. We mapped the 228 births and induced abortions with diagnosis of congenital anomalies observed during the 1998–2006 period, together with a corresponding series of control births matched for year and hospital of birth/abortion as well as maternal age, using maternal address in the first three months of pregnancy to geocode cases and controls. Results Among women residing in the areas with medium and high exposure, prevalence of anomalies in the offspring was substantially comparable to that observed in the control population, nor dose-response relations for any of the major categories of birth defects emerged. Furthermore, odds ratio for congenital anomalies did not decrease during a prolonged shut-down period of the plant. Conclusion Overall, these findings do not lend support to the hypothesis that the environmental contamination occurring around an incineration plant such as that examined in this study may induce major teratogenic effects. PMID:19208225

Medication exposure and spontaneous abortion: a case-control study using a French medical database.

PubMed

Abadie, D; Hurault-Delarue, C; Damase-Michel, C; Montastruc, J L; Lacroix, I

2015-01-01

Few studies have been conducted to investigate drug effects on spontaneous abortion risk. The objective of the present study was to evaluate the potential association between first trimester drug exposure and spontaneous abortion occurrence. The authors performed a nested case-control study using data from TERAPPEL, a French medical database. Cases were the women who had a spontaneous abortion (before the 22nd week of amenorrhea) and controls were women who gave birth to a child. Analyzed variables were: maternal age, obstetric history, tobacco, and alcohol and drug consumption during the first trimester of pregnancy. For comparison of drug exposures between cases and controls, the authors calculated odds ratios (ORs) by means of multivariate logistic regressions adjusted on age and on other drug exposures. The study included 838 cases and 4,508 controls that were identified in the database. In adjusted analyses, cases were more exposed than controls to "non-selective monoamine reuptake inhibitors" [OR=2.2 (CI 95% 1.5-3.3)], "antiprotozoals" [OR = 1.6 (CI 95% 1.1 - 2.5)] and "centrally acting antiobesity products" [OR = 3.4 (CI 95% 1.9 - 6.2)]. Conversely, controls were more exposed than cases to H1 antihistamines [OR = 0.6 (CI 95% 0.4 - 0.9)]. This exploratory study highlights some potential associations between first trimester drug exposure and risk of spontaneous abortion. Further studies have to be carried out to investigate these findings.

Fertility drug use and the risk of ovarian tumors in infertile women: a case-control study.

PubMed

Asante, Albert; Leonard, Phoebe H; Weaver, Amy L; Goode, Ellen L; Jensen, Jani R; Stewart, Elizabeth A; Coddington, Charles C

2013-06-01

To assess the influence of infertility and fertility drugs on risk of ovarian tumors. Case-control study (Mayo Clinic Ovarian Cancer Study). Ongoing academic study of ovarian cancer. A total of 1,900 women (1,028 with ovarian tumors and 872 controls, frequency matched on age and region of residence) who had provided complete information in a self-report questionnaire about history of infertility and fertility drug use. None. Effect of infertility history, use of fertility drugs and oral contraception, and gravidity on the risk of ovarian tumor development, after controlling for potential confounders. Among women who had a history of infertility, use of fertility drugs was reported by 44 (24%) of 182 controls and 38 (17%) of 226 cases. Infertile women who used fertility drugs were not at increased risk of developing ovarian tumors compared with infertile women who did not use fertility drugs; the adjusted odds ratio was 0.64 (95% CI, 0.37, 1.11). The findings were similar when stratified by gravidity and when analyzed separately for borderline versus invasive tumors. We found no statistically significant association between fertility drug use and risk of ovarian tumors. Further larger, prospective studies are needed to confirm this observation. Published by Elsevier Inc.

A case-control study of chronic neuropsychiatric disease and organic solvent exposure in automobile assembly plant workers.

PubMed Central

Nelson, N A; Robins, T G; White, R F; Garrison, R P

1994-01-01

A case-control study of chronic neurological and psychiatric disease and occupational exposure to solvents was carried out in eight automobile assembly plants. Cases included 299 subjects who were granted medical disability retirement in 1980-8. Two control groups were selected, the first from those granted retirement in the same period because of medical disability from causes unrelated to solvent exposure. The second included hourly employees from the plant population. In these facilities, solvent exposures tended to be short term and low level, although common: the average duration of exposure was 2.3 years; about 41% experienced at least one day of exposure. Of those exposed, 46% had less than one year of exposure. Results for all psychiatric disease combined (273 cases) suggested that cases had lower exposures than either control group, regardless of how exposure was expressed. Results could not be explained by conventional confounding exposures or characteristics or by usual manifestations of the healthy worker effect. By contrast, chronic neurological disease, and multiple sclerosis in particular, seemed to be associated with exposure, although few cases were identified and observed increases in risk were not statistically significant. PMID:8199679

On the Analysis of Case-Control Studies in Cluster-correlated Data Settings.

PubMed

Haneuse, Sebastien; Rivera-Rodriguez, Claudia

2018-01-01

In resource-limited settings, long-term evaluation of national antiretroviral treatment (ART) programs often relies on aggregated data, the analysis of which may be subject to ecological bias. As researchers and policy makers consider evaluating individual-level outcomes such as treatment adherence or mortality, the well-known case-control design is appealing in that it provides efficiency gains over random sampling. In the context that motivates this article, valid estimation and inference requires acknowledging any clustering, although, to our knowledge, no statistical methods have been published for the analysis of case-control data for which the underlying population exhibits clustering. Furthermore, in the specific context of an ongoing collaboration in Malawi, rather than performing case-control sampling across all clinics, case-control sampling within clinics has been suggested as a more practical strategy. To our knowledge, although similar outcome-dependent sampling schemes have been described in the literature, a case-control design specific to correlated data settings is new. In this article, we describe this design, discuss balanced versus unbalanced sampling techniques, and provide a general approach to analyzing case-control studies in cluster-correlated settings based on inverse probability-weighted generalized estimating equations. Inference is based on a robust sandwich estimator with correlation parameters estimated to ensure appropriate accounting of the outcome-dependent sampling scheme. We conduct comprehensive simulations, based in part on real data on a sample of N = 78,155 program registrants in Malawi between 2005 and 2007, to evaluate small-sample operating characteristics and potential trade-offs associated with standard case-control sampling or when case-control sampling is performed within clusters.

Risk Factors Profile of Shoulder Dystocia in Oman: A Case Control Study

PubMed Central

Al-Khaduri, Maha M.; Abudraz, Rania Mohammed; Al-Farsi, Yahya M.

2014-01-01

Objective This study aimed to assess the risk factor profile of shoulder dystocia and associated neonatal complications in Oman, a developing Arab country. Methods A retrospective case-control study was conducted among 111 cases with dystocia and 111 controls, identified during 1994-2006 period in a tertiary care hospital in Oman. Controls were randomly selected among women who did not have dystocia, and were matched to cases on the day of delivery. Data related to potential risk factors, delivery, and obstetric complications were collected. Results Dystocia was significantly associated with older maternal age, higher parity, larger BMI, diabetes, and previous record of dystocia. In addition, dystocia was associated more with vacuum and forceps deliveries. Routine traction (51%) was the most used manoeuvre. Among dystocia cases, 13% were associated with fetal complications of which Erb’s Palsy was the most prevalent (79%). Conclusion Our finding of significant associations with risk factors lays out the ground to develop a predictability index for shoulder dystocia, which would help in making it preventable. Further p rospective studies are required to confirm the obtained results. PMID:25337307

[Lung cancer and smoking in Asturias, Spain. A case-control study].

PubMed

Caicoya, M; Mirón, J A

2003-01-01

Lung cancer in Asturias is 1.4-fold greater than the Spanish average, while the proportion of smokers is similar. The objective of this study was to examine the relationship between lung cancer and smoking in Asturias. We performed a hospital-based, incident case control study. The cases were newly diagnosed lung cancer patients and controls were patients from the surgical wards. Information was sought on smoking, occupational exposures, and demographic variables. The analysis was performed by means of odds ratios (OR). One hundred ninety-seven cases and 196 controls were included in the analysis. The adjusted OR of cigarette smoking was 5.77 (95% CI, 2.96-11.22). The risk increased with the number of cigarettes smoked per day (chi 2 = 56.3), the number of packs/year (chi 2 = 48.4), and the age at which smoking started (chi 2 = 76.5). The OR diminished with the number of years of cessation (chi 2 = 39.9). The relationship between smoking and lung cancer in Asturias is similar to that found in other studies carried out in other parts of the western world. The magnitude of the OR may explain the frequency of lung cancer in Asturias. Greater efforts should be devoted to controlling this problem.

First case-control study of zoonotic brucellosis in Gafsa district, Southwest Tunisia.

PubMed

Khamassi Khbou, Médiha; Htira, Samaher; Harabech, Kaouther; Benzarti, M'hammed

2018-06-01

A case-control study was conducted, aimed to describe the clinical human brucellosis (CHB) pattern during 2015 in the Gafsa region (Southwest Tunisia) and to investigate the main risk factors involved in the disease occurrence. One hundred and four CHB cases were notified in 2015 in Gafsa district. All CHB cases that own ruminants were contacted, but only 32 accepted to participate in a matched case-control study. Thirty-two and thirty-one CHB cases and controls, respectively, were included in the study. The subjects were interviewed using a structured questionnaire. A total of 662 domestic ruminants (cattle, sheep and goats) belonging to cases and controls, were screened using the Rose Bengal Test, as recommended by the World Organisation of Animal Health. During 2015, the incidence of CHB was estimated to 30.8 per 100,000 inhabitants affecting mainly males aged between 30 and 39 years. The overall animal seropositivity to Brucella , was 21 and 1.9% in case and control farms, respectively (p < 0.0001). Only five risk factors were found to be significant: overall animal seropositivity (OR = 65.2; 95%CI: 13.3-318.7); handling aborted females (OR = 43.1; 95%CI: 8.3-222.7); presence of male ruminants in the herds (OR = 18.5; 95%CI: 5.18-66); owning seropositive goats (OR = 18.3; 95%CI: 2.4-137.6), owning seropositive sheep (OR = 9.66; 95%CI: 2.9-31.5) and history of abortion during the previous year in the herd (OR = 4.6; 95%CI: 1.3-12.6). Vaccination of animals against brucellosis was associated with lower odds of human brucellosis (OR = 0.03; 95%CI: 0.004-0.2). Raw milk and derivatives consumption was not a risk factor of human brucellosis. Based on this study, ruminants' vaccination coverage should be increased by enhancing the number of vaccinated animals and systematically including male ruminants in Tunisia. Comprehensive education programmes targeting both farmers and general population should be implemented.

Analysis of single nucleotide polymorphisms in case-control studies.

PubMed

Li, Yonghong; Shiffman, Dov; Oberbauer, Rainer

2011-01-01

Single nucleotide polymorphisms (SNPs) are the most common type of genetic variants in the human genome. SNPs are known to modify susceptibility to complex diseases. We describe and discuss methods used to identify SNPs associated with disease in case-control studies. An outline on study population selection, sample collection and genotyping platforms is presented, complemented by SNP selection, data preprocessing and analysis.

Risk factors in facial hyperpigmentation in Maghrebian population - a case-control study.

PubMed

Benchikhi, H; Atide, N; Jroundi, I; Humbert, P; Lakhdar, H

2012-10-01

Triggering factors seem to be multiple in the pathogenesis of facial hyperpigmentation (FH), as dark skin types, pregnancy, sun exposure… The aim of this study was to investigate the risk factors for FH in Maghrebian population. Patients with FH were included in a case-controlled study. Following data were recorded: age, sex, parity, phototype, FH and hormonal-related history, endocrinological features, sunlight exposure, specific cultural behaviours, use of topic corticosteroids and sunscreens. One hundred women (mean age 29.5 ± 13.7 years) were included with 200 age-matched controls. Duration of FH was 32.9 ± 42.2 months. There was a statistically significant relation between FH and hirsutism (P = 0.009), troubles of menstruations (P = 0.008), but not with acne (P = 0.23) and contraceptive oral (P = 0.06) drugs or with history of thyroid disorders (P = 0.13). For cultural factors, there were a statistical significant relation with rubbing by flannel glove (P < 0.05), use of dark soap (P = 0.009) and traditional masks (P < 0.05) but both groups were used to go to hammam. A strong relation was observed between FH and use of topical corticosteroids: 40% in the FH group vs. 5% in the control group (P < 0.05). Both groups used to apply sunscreens: 70% in the FH group and 67% in the control group where as there were no differences in the two groups for sun exposure. No statistical differences were observed regarding to age, phototypes and grade of parity. Our study demonstrated a relation between FH and hyperestrogenemia, rubbing with a friction glove, use of moroccan traditional masks and application of topical steroids. The eviction of all these triggering factors could be an adjuvant recommendation in the assessment of FH. © 2012 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

A probability model for evaluating the bias and precision of influenza vaccine effectiveness estimates from case-control studies.

PubMed

Haber, M; An, Q; Foppa, I M; Shay, D K; Ferdinands, J M; Orenstein, W A

2015-05-01

As influenza vaccination is now widely recommended, randomized clinical trials are no longer ethical in many populations. Therefore, observational studies on patients seeking medical care for acute respiratory illnesses (ARIs) are a popular option for estimating influenza vaccine effectiveness (VE). We developed a probability model for evaluating and comparing bias and precision of estimates of VE against symptomatic influenza from two commonly used case-control study designs: the test-negative design and the traditional case-control design. We show that when vaccination does not affect the probability of developing non-influenza ARI then VE estimates from test-negative design studies are unbiased even if vaccinees and non-vaccinees have different probabilities of seeking medical care against ARI, as long as the ratio of these probabilities is the same for illnesses resulting from influenza and non-influenza infections. Our numerical results suggest that in general, estimates from the test-negative design have smaller bias compared to estimates from the traditional case-control design as long as the probability of non-influenza ARI is similar among vaccinated and unvaccinated individuals. We did not find consistent differences between the standard errors of the estimates from the two study designs.

Impact of hospitalizations for bronchiolitis in preterm infants on long-term health care costs in Italy: a retrospective case-control study.

PubMed

Roggeri, Daniela Paola; Roggeri, Alessandro; Rossi, Elisa; Cataudella, Salvatore; Martini, Nello

2016-01-01

Bronchiolitis is an acute inflammatory injury of the bronchioles, and is the most frequent cause of hospitalization for lower respiratory tract infections in preterm infants. This was a retrospective, observational, case-control study conducted in Italy, based on administrative database analysis. The aim of this study was to evaluate differences in health care costs of preterm infants with and without early hospitalization for bronchiolitis. Preterm infants born in the period between January 1, 2009 and December 31, 2010 and hospitalized for bronchiolitis in the first year of life were selected from the ARNO Observatory database and observed for the first 4 years of life. These preterm infants were compared (paired 1-3) with preterm infants who were not hospitalized for bronchiolitis in the first year of life and with similar characteristics. Only direct health care costs reimbursed by the Italian National Health Service were considered for this study (drugs, hospitalizations, and diagnostic/therapeutic procedures). Of 40,823 newborns in the accrual period, 863 were preterm with no evidence of prophylaxis, and 22 preterm infants were hospitalized for bronchiolitis (cases) and paired with 62 controls. Overall, cases had 74% higher average cost per infant in the first 4 years of life than controls (18,624€ versus 10,189€, respectively). The major cost drivers were hospitalizations, accounting for >90% in both the populations. The increase in total yearly health care cost between cases and controls remained substantial even in the fourth year of life for all cost items. A relevant increase in hospitalizations and drug consumption linked to respiratory tract diseases was noted in infants hospitalized for bronchiolitis during the entire follow-up period. Preterm infants hospitalized for bronchiolitis in the first year of life were associated with increased resource consumption and costs throughout the entire period of observation; even in the fourth year, the

Analyzing self-controlled case series data when case confirmation rates are estimated from an internal validation sample.

PubMed

Xu, Stanley; Clarke, Christina L; Newcomer, Sophia R; Daley, Matthew F; Glanz, Jason M

2018-05-16

Vaccine safety studies are often electronic health record (EHR)-based observational studies. These studies often face significant methodological challenges, including confounding and misclassification of adverse event. Vaccine safety researchers use self-controlled case series (SCCS) study design to handle confounding effect and employ medical chart review to ascertain cases that are identified using EHR data. However, for common adverse events, limited resources often make it impossible to adjudicate all adverse events observed in electronic data. In this paper, we considered four approaches for analyzing SCCS data with confirmation rates estimated from an internal validation sample: (1) observed cases, (2) confirmed cases only, (3) known confirmation rate, and (4) multiple imputation (MI). We conducted a simulation study to evaluate these four approaches using type I error rates, percent bias, and empirical power. Our simulation results suggest that when misclassification of adverse events is present, approaches such as observed cases, confirmed case only, and known confirmation rate may inflate the type I error, yield biased point estimates, and affect statistical power. The multiple imputation approach considers the uncertainty of estimated confirmation rates from an internal validation sample, yields a proper type I error rate, largely unbiased point estimate, proper variance estimate, and statistical power. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chronic urinary tract infection and bladder carcinoma risk: a meta-analysis of case-control and cohort studies.

PubMed

Akhtar, Saeed; Al-Shammari, Ahmad; Al-Abkal, Jarrah

2018-02-05

This meta-analysis of published case-control and cohort studies sought to quantify the magnitude and direction of association between chronic UTI (defined as the infection of the urinary tract that either does not respond to treatment or keeps recurring) and risk of bladder carcinoma (BCa) (i.e., including mainly urothelial carcinoma, squamous cell carcinoma or adenocarcinoma). A literature search was conducted using Medline, Embase, Ovid, Web of Science, Science Direct and Cochrane Library, which was supplemented with manual search of reference lists of the identified articles. Case-control and cohort studies examining UTI as a predictor of BCa risk published through June 2016 were eligible. Using random-effects models, odds ratios (OR) or relative risks (RR) from eligible studies were combined to synthesize summary effect estimates. The included studies were assessed for methodological quality and potential publication bias. Heterogeneity by study characteristics was examined by sub-group and meta-regression analyses. Eighteen case-control and three cohort studies published between 1963 and 2016 were eligible. Random-effects models showed that UTI was significantly associated with an increased BCa risk both in case-control studies (summary OR RE  = 2.33; 95% CI 1.86, 2.92) and cohort studies (summary RR RE  = 2.88; 95% CI 1.20, 6.89). The observed relationship of UTI with an increased BCa risk was independent of the study characteristics considered. No significant publication bias was detected. Chronic UTI was significantly and independently associated with an increased BCa risk. However, due to the presence of high between-study heterogeneity and inconsistent patterns of adjusted confounding effects, more data are needed to clarify the role of chronic UTI in causation of BCa and if established, prompt and effective treatment of UTI may minimize a substantial proportion of BCa risk.

Snippets from the past: is Flint, Michigan, the birthplace of the case-control study?

PubMed

Morabia, Alfredo

2013-12-15

In the summer of 1924, an outbreak of scarlet fever occurred in Flint, Michigan. Unable to trace it to the usual causes, particularly fresh milk, the Michigan Department of Health used a novel approach to disentangle the enigma: The 116 cases of scarlet fever were compared with 117 "controls" selected from neighbors of the quarantined cases and from patients at the City Health Center who had been treated for ailments unrelated to scarlet fever. The extraordinary culprit was ice cream, which had a frequent/occasional/none consumption prevalence of 60%, 34%, and 6% among the cases and 24%, 51%, and 25% among the controls, respectively. The 1925 report reads, "Detailed epidemiological investigation, by means of case histories and control histories on well persons, confirmed early suspicions and established the fact that the epidemic was spread by ice cream" (Am J Hyg. 1925;5(5):669-681). This forgotten epidemiologic study is the oldest study using the case-control design to have been resurrected thus far. The case-control study design may have been conceived simultaneously, but independently and for different purposes, in England (Janet Lane-Claypon's 1926 report on the determinants of breast cancer) and the United States.

Novel ways to explore surgical interventions in randomised controlled trials: applying case study methodology in the operating theatre.

PubMed

Blencowe, Natalie S; Blazeby, Jane M; Donovan, Jenny L; Mills, Nicola

2015-12-28

Multi-centre randomised controlled trials (RCTs) in surgery are challenging. It is particularly difficult to establish standards of surgery and ensure that interventions are delivered as intended. This study developed and tested methods for identifying the key components of surgical interventions and standardising interventions within RCTs. Qualitative case studies of surgical interventions were undertaken within the internal pilot phase of a surgical RCT for obesity (the By-Band study). Each case study involved video data capture and non-participant observation of gastric bypass surgery in the operating theatre and interviews with surgeons. Methods were developed to transcribe and synchronise data from video recordings with observational data to identify key intervention components, which were then explored in the interviews with surgeons. Eight qualitative case studies were undertaken. A novel combination of video data capture, observation and interview data identified variations in intervention delivery between surgeons and centres. Although surgeons agreed that the most critical intervention component was the size and shape of the gastric pouch, there was no consensus regarding other aspects of the procedure. They conceded that evidence about the 'best way' to perform bypass was lacking and, combined with the pragmatic nature of the By-Band study, agreed that strict standardisation of bypass might not be required. This study has developed and tested methods for understanding how surgical interventions are designed and delivered delivered in RCTs. Applying these methods more widely may help identify key components of interventions to be delivered by surgeons in trials, enabling monitoring of key components and adherence to the protocol. These methods are now being tested in the context of other surgical RCTs. Current Controlled Trials ISRCTN00786323 , 05/09/2011.

A case control study of nutritional factors and cervical dysplasia.

PubMed

Liu, T; Soong, S J; Wilson, N P; Craig, C B; Cole, P; Macaluso, M; Butterworth, C E

1993-01-01

The association of nutritional factors with cervical dysplasia was examined through a case-control study. Analysis was conducted in 257 cases and 133 controls confirmed both by cytological examination and colposcopic findings. A 24-h dietary recall questionnaire was used to assess nutritional intake. Various risk factors (including age at first intercourse, number of sexual partners, parity, cigarette smoking, oral contraceptive use, human papillomavirus type 16 infection, and age and race) were adjusted for their potential confounding effects. While analyses were also performed to adjust for total calories, results were not changed significantly. Among the nutrients examined, vitamin A intake showed a significantly increased risk at the lowest quartile compared to the highest quartile, with an odds ratio of 2.2 (95% confidence interval, 1.2-4.2). A significant trend of increasing risk was also observed with lower intake of vitamin A (P = 0.05). Riboflavin showed increased risk at the two lower quartiles of intake with a trend test P value of 0.04. Increased risk was also found for lower intakes of vitamin C compared to the highest intake level. For folate, increased risk was found in the second highest quartile compared with the highest quartile with an odds ratio of 2.0 (95% confidence interval, 1.0-3.8). The calcium:phosphorus ratio showed an increased risk at the lowest level (odds ratio, 2.0; 95% confidence interval, 1.0-4.3). Insufficient intake of vitamin A, riboflavin, ascorbate, and folate is associated with an increased risk of cervical dysplasia.

Toxoplasma gondii exposure and Parkinson's disease: a case-control study.

PubMed

Alvarado-Esquivel, Cosme; Méndez-Hernández, Edna Madai; Salas-Pacheco, José Manuel; Ruano-Calderón, Luis Ángel; Hernández-Tinoco, Jesús; Arias-Carrión, Oscar; Sánchez-Anguiano, Luis Francisco; Castellanos-Juárez, Francisco Xavier; Sandoval-Carrillo, Ada Agustina; Liesenfeld, Oliver; Ramos-Nevárez, Agar

2017-02-13

To determine the association between Toxoplasma gondii infection and Parkinson's disease and to investigate whether T. gondii seropositivity is associated with the general characteristics of patients with Parkinson's disease. Case-control study. Cases and controls were enrolled in Durango City, Mexico. 65 patients with Parkinson's disease and 195 age- and gender-matched control subjects without Parkinson's disease. Serum samples of participants were analysed for anti- T. gondii IgG and IgM antibodies by commercially available enzyme-linked immunoassays. Prevalence of T. gondii DNA was determined in seropositive subjects using PCR. The association between clinical data and infection was examined by bivariate analysis. Anti- T. gondii IgG antibodies were found in 6/65 cases (9.2%) and in 21/195 controls (10.8%) (OR 0.84; 95% CI 0.32 to 2.18; p=0.81). The frequency of high (>150 IU/mL) antibody levels was similar among cases and controls (p=0.34). None of the anti- T. gondii IgG positive cases and four of the anti- T. gondii IgG positive controls had anti- T. gondii IgM antibodies (p=0.54). The prevalence of T. gondii DNA was comparable in seropositive cases and controls (16.7% and 25%, respectively; p=1.0). Seroprevalence of T. gondii infection was associated with a young age onset of disease (p=0.03), high Unified Parkinson Disease Rating Scale scores (p=0.04) and depression (p=0.02). Seropositivity to T. gondii infection was lower in patients treated with pramipexole than in patients without this treatment (p=0.01). However, none of the associations remained significant after Bonferroni correction. The results do not support an association between T. gondii infection and Parkinson's disease. However, T. gondii infection might have an influence on certain symptoms of Parkinson's disease. Further research to elucidate the role of T. gondii exposure on Parkinson's disease is warranted. Published by the BMJ Publishing Group Limited. For permission to use (where not

Psychological vulnerability in children next-born after stillbirth: a case-control follow-up study.

PubMed

Turton, Penelope; Badenhorst, William; Pawlby, Susan; White, Sarah; Hughes, Patricia

2009-12-01

Case studies and anecdotal accounts suggest that perinatal loss may impact upon other children in the family, including those born subsequent to loss. However, there is a dearth of systematically collected quantitative data on this potentially vulnerable group. Case-controlled follow-up of 52 mothers with history of stillbirth with their next-born children aged 6-8 years, and 51 control mother-child dyads. Previously reported baseline data included maternal antenatal and postnatal psychological assessment, and infant security of attachment at 12 months. Follow-up assessments included maternal psychiatric and socio-demographic data, mother and teacher-rated scales of the child's strengths and difficulties, child IQ, observer-rated mother-child interaction and maternal reports of child health. There were no significant between-group differences in child cognitive or health assessments, or in teacher-rated child difficulties. However, mothers with history of stillbirth (the index group) reported increased child difficulties, in particular peer problems, and more adverse interaction was observed in respect of higher levels of maternal criticism of the child's actions, more overall controlling behaviour by the mother, a less harmonious emotional atmosphere and a lower level of maternal engagement with the child. Some of these effects appeared to be mediated by maternal perinatal psychological symptoms and family breakdown. This study provides no evidence to suggest that siblings born after stillbirth are clinically at risk but does lend empirical support to clinical reports that such children are seen by their mothers as having problems and that they are exposed to less optimal interaction with their mothers. Possible interpretations of these findings are discussed in the context of theoretical accounts of 'replacement child' and 'vulnerable child' syndromes.

Drugs with potential chemopreventive properties in relation to epithelial ovarian cancer--a nationwide case-control study.

PubMed

Baandrup, Louise

2015-07-01

Paper 1, and 4103 epithelial ovarian cancer cases and 58,706 controls in Papers 2 and 3. We used the Danish Prescription Registry to assess use (≥2 prescriptions on separate dates) of paracetamol, non-aspirin non-steroidal anti-inflammatory drugs (NSAIDs), low-dose aspirin, and statins. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for epithelial ovarian cancer associated with use of the study drugs, with adjustment for potential confounding factors selected a priori. We performed detailed analyses according to duration, intensity, and continuity of study drug use, and the analyses were stratified according to specific histologic types of epithelial ovarian cancer. In all studies, non-use (< 2 prescriptions) of the individual study drugs was defined as the reference group. A striking result of the PhD thesis was a strong inverse association between prescription use of paracetamol and risk of epithelial ovarian cancer. The risk estimates decreased with increasing duration and intensity of paracetamol use, reaching a more than 50% reduction for the longest duration (>10 years) and the highest doses (OR: 0.45; 95% CI: 0.24-0.86). In contrast, we did not observe an inverse association between use of non-aspirin NSAIDs and risk of epithelial ovarian cancer. Moreover, this thesis provides further evidence that use of low-dose aspirin is associated with a reduced risk of epithelial ovarian cancer. In particular, long-term (≥5 years) continuous use of low-dose aspirin, defined as overlapping prescription coverage periods, was associated with a large reduction in risk (OR: 0.56; 95% CI: 0.32-0.97). Finally, we found no apparent association between statin use and epithelial ovarian cancer risk, although the analysis by histologic type suggested an inverse association with the risk of mucinous tumors. The results of this PhD thesis add important knowledge to the area of chemoprevention in relation to epithelial

Effectiveness of monovalent rotavirus vaccine in Bolivia: case-control study.

PubMed

Patel, Manish M; Patzi, Maritza; Pastor, Desiree; Nina, Aleida; Roca, Yelin; Alvarez, Leovigildo; Iniguez, Volga; Rivera, Rosario; Tam, Ka Ian; Quaye, Osbourne; Bowen, Michael; Parashar, Umesh; De Oliveira, Lucia Helena

2013-06-19

To evaluate the effectiveness of two doses of a monovalent rotavirus vaccine (RV1) against hospital admission for rotavirus in Bolivia. Case-control study. Six hospitals in Bolivia, between March 2010 and June 2011. 400 hospital admissions for rotavirus, 1200 non-diarrhea hospital controls, and 718 rotavirus negative hospital controls. Odds of antecedent vaccination between case patients and controls; effectiveness of vaccination ((1-adjusted odds ratio)×100), adjusted for age and other confounders; and stratified effectiveness by dose, disease severity, age group, and serotype. In comparison with non-diarrhea controls, case patients were more likely to be male and attend day care but less likely to have chronic underlying illness, higher level maternal education, and telephones and computers in their home. Rotavirus negative controls were somewhat more similar to case patients but also were more likely to be male and attend day care and less likely to have higher level maternal education and computers in their homes. The adjusted effectiveness of RV1 against hospital admission for rotavirus was 69% (95% confidence interval 54% to 79%) with rotavirus negative controls and 77% (65% to 84%) with non-diarrhea controls. The effectiveness of one dose of RV1 was 36% and 56%, respectively. With both control groups, protection was sustained through two years of life, with similar efficacy against hospital admission among children under 1 year (64% and 77%) and over 1 year of age (72% and 76%). RV1 provided significant protection against diverse serotypes, partially and fully heterotypic to the G1P[8] vaccine. Effectiveness using the two control groups was 80% and 85% against G9P[8], 74% and 93%% against G3P[8], 59% and 69% against G2P[4], and 80% and 87% against G9P[6] strains. The monovalent rotavirus vaccine conferred high protection against hospital admission for diarrhea due to rotavirus in Bolivian children. Protection was sustained through two years of life against

Case-control study on the prevention of occupational eye injuries.

PubMed

Ho, Chi-Kung; Yen, Ya-Lin; Chang, Cheng-Hsien; Chiang, Hung-Che; Shen, Ying-Ying; Chang, Po-Ya

2008-01-01

The risk factors for occupational eye injuries have never been published in Taiwan. We conducted a case-control study to analyze the differences among workers on their knowledge, attitude to and practice (KAP) of occupational accident prevention. In the study, a statistical model was also set up for predicting the occupational problem. Subjects, including 31 cases of work-related eye injuries and 62 controls, completed a structured questionnaire on KAP, which revealed that 80.6% and 62.7% of workers in the case and control groups, respectively, did not wear eye protection during work. Furthermore, we found that temporary employment (OR, 10.7; 95% CI, 3.03-36.16) and fewer than 10 years of education (OR, 4.44; 95% CI, 1.73-11.44) were the major risk factors for occupational eye injuries. In addition, we developed a logistic regression model with four predictors (temporary employment, education years less than 10, poor management of industrial health and safety in the workplace, and poor attitude towards accident prevention) for the occurrence of occupational eye injuries. In conclusion, in Taiwan, compulsory regulation of wearing eye protection during work, good education, management of work safety and hygiene and employee (especially temporary worker) commitment to safety and health are strongly recommended prevention strategies.

Case studies of power and control related to tobacco use during pregnancy.

PubMed

Greaves, Lorraine; Kalaw, Cecilia; Bottorff, Joan L

2007-01-01

The objective was to identify and describe elements of power and control evident in couple tobacco-related interaction patterns during pregnancy. Using a case study approach, elements of the Duluth Abuse Intervention Project Power and Control Wheel were used to examine women's experiences of tobacco reduction during pregnancy and post partum. Three cases were selected from a larger qualitative sample, using a maximum variation sampling approach. Although no direct evidence of partner abuse or violence accompanying partner efforts to influence women's smoking was described, most of the elements of power and control were present in the case study, and appeared to cause an emotional toll and a negative impact on women's ability to freely express their views about their own tobacco use. Elements of power and control, however subtle, are potentially important and unrecognized dimensions of women's tobacco reduction experiences. Additional care and attention should be taken in designing tobacco reduction interventions and policies directed at pregnant and post partum women and their partners to reduce the possibility that these interventions may contribute to the use of power and control.

Creation of an ensemble of simulated cardiac cases and a human observer study: tools for the development of numerical observers for SPECT myocardial perfusion imaging

NASA Astrophysics Data System (ADS)

O'Connor, J. Michael; Pretorius, P. Hendrik; Gifford, Howard C.; Licho, Robert; Joffe, Samuel; McGuiness, Matthew; Mehurg, Shannon; Zacharias, Michael; Brankov, Jovan G.

2012-02-01

Our previous Single Photon Emission Computed Tomography (SPECT) myocardial perfusion imaging (MPI) research explored the utility of numerical observers. We recently created two hundred and eighty simulated SPECT cardiac cases using Dynamic MCAT (DMCAT) and SIMIND Monte Carlo tools. All simulated cases were then processed with two reconstruction methods: iterative ordered subset expectation maximization (OSEM) and filtered back-projection (FBP). Observer study sets were assembled for both OSEM and FBP methods. Five physicians performed an observer study on one hundred and seventy-nine images from the simulated cases. The observer task was to indicate detection of any myocardial perfusion defect using the American Society of Nuclear Cardiology (ASNC) 17-segment cardiac model and the ASNC five-scale rating guidelines. Human observer Receiver Operating Characteristic (ROC) studies established the guidelines for the subsequent evaluation of numerical model observer (NO) performance. Several NOs were formulated and their performance was compared with the human observer performance. One type of NO was based on evaluation of a cardiac polar map that had been pre-processed using a gradient-magnitude watershed segmentation algorithm. The second type of NO was also based on analysis of a cardiac polar map but with use of a priori calculated average image derived from an ensemble of normal cases.

Adaptation of Chain Event Graphs for use with Case-Control Studies in Epidemiology.

PubMed

Keeble, Claire; Thwaites, Peter Adam; Barber, Stuart; Law, Graham Richard; Baxter, Paul David

2017-09-26

Case-control studies are used in epidemiology to try to uncover the causes of diseases, but are a retrospective study design known to suffer from non-participation and recall bias, which may explain their decreased popularity in recent years. Traditional analyses report usually only the odds ratio for given exposures and the binary disease status. Chain event graphs are a graphical representation of a statistical model derived from event trees which have been developed in artificial intelligence and statistics, and only recently introduced to the epidemiology literature. They are a modern Bayesian technique which enable prior knowledge to be incorporated into the data analysis using the agglomerative hierarchical clustering algorithm, used to form a suitable chain event graph. Additionally, they can account for missing data and be used to explore missingness mechanisms. Here we adapt the chain event graph framework to suit scenarios often encountered in case-control studies, to strengthen this study design which is time and financially efficient. We demonstrate eight adaptations to the graphs, which consist of two suitable for full case-control study analysis, four which can be used in interim analyses to explore biases, and two which aim to improve the ease and accuracy of analyses. The adaptations are illustrated with complete, reproducible, fully-interpreted examples, including the event tree and chain event graph. Chain event graphs are used here for the first time to summarise non-participation, data collection techniques, data reliability, and disease severity in case-control studies. We demonstrate how these features of a case-control study can be incorporated into the analysis to provide further insight, which can help to identify potential biases and lead to more accurate study results.

Factors Associated with Tuberculosis Treatment Default in an Endemic Area of the Brazilian Amazon: A Case Control-Study

PubMed Central

Garrido, Marlucia da Silva; Penna, Maria Lucia; Perez-Porcuna, Tomàs M.; de Souza, Alexandra Brito; Marreiro, Leni da Silva; Albuquerque, Bernardino Claudio; Martínez-Espinosa, Flor Ernestina; Bührer-Sékula, Samira

2012-01-01

Setting Treatment default is a serious problem in tuberculosis control because it implies persistence of infection source, increased mortality, increased relapse rates and facilitates the development of resistant strains. Objective This study analyzed tuberculosis treatment default determinants in the Amazonas State to contribute in planning appropriate control interventions. Design Observational study with a retrospective cohort using Brazilian Disease Notification System data from 2005 to 2010. A nested case control study design was used. Patients defaulting from treatment were considered as ‘cases’ and those completing treatment as ‘controls’. In the analysis, 11,312 tuberculosis patients were included, 1,584 cases and 9,728 controls. Results Treatment default was observed to be associated to previous default (aOR 3.20; p<0.001), HIV positivity (aOR 1.62; p<0.001), alcoholism (aOR 1.51; p<0.001), low education level (aOR 1.35; p<0.001) and other co-morbidities (aOR 1.31; p = 0.05). Older patients (aOR 0.98; p = 0.001) and DOT (aOR 0,72; p<0.01) were considered as protective factor for default. Conclusions Associated factors should be considered in addressing care and policy actions to tuberculosis control. Information on disease and treatment should be intensified and appropriate to the level of education of the population, in order to promote adherence to treatment and counter the spread of multidrug resistance to anti-TB drugs. PMID:22720052

Case-control study of childhood acute lymphoblastic leukemia and residential radon exposure.

PubMed

Lubin, J H; Linet, M S; Boice, J D; Buckley, J; Conrath, S M; Hatch, E E; Kleinerman, R A; Tarone, R E; Wacholder, S; Robison, L L

1998-02-18

Several ecologic analyses have shown significant positive associations between mean indoor radon concentrations and risk of leukemia at all ages (acute myeloid leukemia and chronic lymphocytic leukemia) and for children (all leukemia, acute myeloid leukemia, and acute lymphoblastic leukemia [ALL]). As part of an age-matched, case-control study of childhood ALL in the United States, we investigated the association between the incidence of ALL in children under age 15 years and indoor radon exposure. Radon detectors were placed in current and previous homes of subjects where they resided for 6 months or longer. Children were included in analyses if radon measurements covered 70% or more of the 5-year period prior to diagnosis for case subjects (or from birth for case subjects under age 5 years) and the corresponding reference dates for control subjects. Radon levels could be estimated for 97% of the exposure period for the eligible 505 case subjects and 443 control subjects. Mean radon concentration was lower for case subjects (65.4 becquerels per cubic meter [Bqm(-3)]) than for control subjects (79.1 Bqm(-3)). For categories less than 37, 37-73, 74-147, and 148 or more Bqm(-3) of radon exposure, relative risks based on matched case-control pairs were 1.00, 1.22, 0.82, and 1.02, respectively, and were similar to results from an unmatched analysis. There was no association between ALL and radon exposure within subgroups defined by categories of age, income, birth order, birth weight, sex, type of residence, magnetic field exposure, parental age at the subject's birth, parental occupation, or parental smoking habits. In contrast to prior ecologic studies, the results from this analytic study provide no evidence for an association between indoor radon exposure and childhood ALL.

Reduction in dengue cases observed during mass control of Aedes (Stegomyia) in street catch basins in an endemic urban area in Colombia

PubMed Central

Ocampo, Clara B.; Mina, Neila Julieth; Carabalí, Mabel; Alexander, Neal; Osorio, Lyda

2015-01-01

Dengue incidence continues to increase globally and, in the absence of an efficacious vaccine, prevention strategies are limited to vector control. It has been suggested that targeting the most productive breeding sites instead of all water-holding containers could be a cost-effective vector control strategy. We sought to identify and continuously control the most productive Aedes (Stegomyia) breeding site in an endemic urban area in Colombia and followed the subsequent incidence of dengue. In the urban area of Guadalajara de Buga, southwestern Colombia, potential breeding sites inside and outside houses were first characterized, and local personnel trained to assess their productivity based on the pupae/person index. Simultaneously, training and monitoring were implemented to improve the dengue case surveillance system. Entomological data and insecticide resistance studies were used to define the targeted intervention. Then, a quasi-experimental design was used to assess the efficacy of the intervention in terms of the positivity index of the targeted and non- targeted breeding sites, and the impact on dengue cases. Street catch basins (storm drains) were the potential breeding site most frequently found containing Aedes immature stages in the baseline (58.3% of 108). Due to the high resistance to temephos (0% mortality after 24 h), the intervention consisted of monthly application of pyriproxyfen in all the street catch basins (n = 4800). A significant decrease in catch basins positivity for Aedes larvae was observed after each monthly treatment (p < 0.001). Over the intervention period, a reduction in the dengue incidence in Buga was observed (rate ratio 0.19, 95% CI 0.12–0.30, p < 0.0001) after adjusting for autocorrelation and controlling with a neighboring town, Palmira, This study highlights the importance of street catch basins as Aedes breeding sites and suggests that their targeted control could help to decrease dengue transmission in such areas. PMID

Reengagement in PTSD psychotherapy: A case-control study.

PubMed

Buchholz, Katherine R; Bohnert, Kipling M; Pfeiffer, Paul N; Valenstein, Marcia; Ganoczy, Dara; Anderson, RaeAnn E; Sripada, Rebecca K

2017-09-01

This study sought to identify patient characteristics and care processes related to reengagement in VA psychotherapy. Using national VA data, a retrospective cohort was constructed (N=24,492) of veterans who received a new PTSD diagnosis in FY08/FY09 and attended only one to five PTSD psychotherapy sessions. A nested case-control study was conducted comparing veterans who reengaged in psychotherapy (n=9649) in a 1:5 ratio with those who did not reengage by the end of FY12. Conditional logistic regression models were run to examine differences in sociodemographic, mental health, and service utilization factors between cases and controls. Among veterans in the study cohort, 39.4% reengaged in psychotherapy. In adjusted analyses, all measured types of health system encounters (primary care [OR=1.61], primary care mental health [OR=1.61], non-PTSD psychotherapy [OR=1.76], other non-PTSD mental health care [OR=1.43], other non-psychotherapy PTSD care [OR=3.31], emergency room [OR=1.14], and psychiatric hospitalization [OR=1.56]) were related to greater odds of reengagement in PTSD psychotherapy. Veterans' receipt of a broad range of care services may play an important role in reengagement in PCT psychotherapy, suggesting providers across care settings should be knowledgeable in how to support a Veteran's return to psychotherapy for PTSD. Published by Elsevier Inc.

Trachoma and Relative Poverty: A Case-Control Study

PubMed Central

Habtamu, Esmael; Wondie, Tariku; Aweke, Sintayehu; Tadesse, Zerihun; Zerihun, Mulat; Zewdie, Zebideru; Callahan, Kelly; Emerson, Paul M.; Kuper, Hannah; Bailey, Robin L.; Mabey, David C. W.; Rajak, Saul N.; Polack, Sarah; Weiss, Helen A.; Burton, Matthew J.

2015-01-01

Background Trachoma is widely considered a disease of poverty. Although there are many epidemiological studies linking trachoma to factors normally associated with poverty, formal quantitative data linking trachoma to household economic poverty within endemic communities is very limited. Methodology/Principal Findings Two hundred people with trachomatous trichiasis were recruited through community-based screening in Amhara Region, Ethiopia. These were individually matched by age and gender to 200 controls without trichiasis, selected randomly from the same sub-village as the case. Household economic poverty was measured through (a) A broad set of asset-based wealth indicators and relative household economic poverty determined by principal component analysis (PCA, (b) Self-rated wealth, and (c) Peer-rated wealth. Activity participation data were collected using a modified ‘Stylised Activity List’ developed for the World Bank’s Living Standards Measurement Survey. Trichiasis cases were more likely to belong to poorer households by all measures: asset-based analysis (OR = 2.79; 95%CI: 2.06–3.78; p<0.0001), self-rated wealth (OR, 4.41, 95%CI, 2.75–7.07; p<0.0001) and peer-rated wealth (OR, 8.22, 95% CI, 4.59–14.72; p<0.0001). Cases had less access to latrines (57% v 76.5%, p = <0.0001) and higher person-to-room density (4.0 v 3.31; P = 0.0204) than the controls. Compared to controls, cases were significantly less likely to participate in economically productive activities regardless of visual impairment and other health problems, more likely to report difficulty in performing activities and more likely to receive assistance in performing productive activities. Conclusions/Significance This study demonstrated a strong association between trachomatous trichiasis and relative poverty, suggesting a bidirectional causative relationship possibly may exist between poverty and trachoma. Implementation of the full SAFE strategy in the context of general improvements

Comparison of two control groups for estimation of oral cholera vaccine effectiveness using a case-control study design.

PubMed

Franke, Molly F; Jerome, J Gregory; Matias, Wilfredo R; Ternier, Ralph; Hilaire, Isabelle J; Harris, Jason B; Ivers, Louise C

2017-10-13

Case-control studies to quantify oral cholera vaccine effectiveness (VE) often rely on neighbors without diarrhea as community controls. Test-negative controls can be easily recruited and may minimize bias due to differential health-seeking behavior and recall. We compared VE estimates derived from community and test-negative controls and conducted bias-indicator analyses to assess potential bias with community controls. From October 2012 through November 2016, patients with acute watery diarrhea were recruited from cholera treatment centers in rural Haiti. Cholera cases had a positive stool culture. Non-cholera diarrhea cases (test-negative controls and non-cholera diarrhea cases for bias-indicator analyses) had a negative culture and rapid test. Up to four community controls were matched to diarrhea cases by age group, time, and neighborhood. Primary analyses included 181 cholera cases, 157 non-cholera diarrhea cases, 716 VE community controls and 625 bias-indicator community controls. VE for self-reported vaccination with two doses was consistent across the two control groups, with statistically significant VE estimates ranging from 72 to 74%. Sensitivity analyses revealed similar, though somewhat attenuated estimates for self-reported two dose VE. Bias-indicator estimates were consistently less than one, with VE estimates ranging from 19 to 43%, some of which were statistically significant. OCV estimates from case-control analyses using community and test-negative controls were similar. While bias-indicator analyses suggested possible over-estimation of VE estimates using community controls, test-negative analyses suggested this bias, if present, was minimal. Test-negative controls can be a valid low-cost and time-efficient alternative to community controls for OCV effectiveness estimation and may be especially relevant in emergency situations. Copyright © 2017. Published by Elsevier Ltd.

A breast cancer case-control study in Girona, Spain. Endocrine, familial and lifestyle factors.

PubMed

Viladiu, P; Izquierdo, A; de Sanjosé, S; Bosch, F X

1996-10-01

This study was designed to explore risk factors for breast cancer with emphasis on the detection of clinical markers of the hormonal imbalance during the perimenarche. Three hundred and thirty women diagnosed with breast cancer and 346 population controls were identified and interviewed in Girona, Spain between 1986 and 89. Cases were more likely than controls to have had long menstrual periods in the first 5 years after menarche [odds ratio (OR) = 3.0], to experience menopause at a late age (OR = 1.5) and to report acne during adolescence (OR = 1.6). Family history of breast cancer was associated with an increased risk (OR = 2.3). Cases reported a lower use of drug treatments for anxiety and sleep disorders than controls. Moderate alcohol drinkers and smokers were at lower risk for breast cancer. No statistically significant association with breast cancer was observed for number of children, age at last pregnancy, oral contraceptive use, hormonal treatment after menopause and weight perception during the teenage years. Hormonal changes in the years following menarche may be relevant to breast cancer risk. The roles of menstrual period length and acne during adolescence should be further explored.

A case control study of senile cataract in a hospital based population.

PubMed

Badrinath, S S; Sharma, T; Biswas, J; Srinivas, V

1996-12-01

A case-control study (244 cases and 264 controls) was done during 1986-89 on a hospital based population to evaluate the risk factors associated with the etiology of senile cataract. Patient with age between 40-60 years, visual acuity of 6/9 or less, and presence of lenticular opacity of senile origin were included as cases. Age matched individuals with absence of lenticular opacity made up the controls. Multivariate logistic regression analysis revealed that higher systolic BP and number of meals were significantly (P < or = 0.05) associated with presence of senile cataract; whereas higher weight, education and income, and utilization of cooking water had a significant protective effect against senile cataract. The present study helps the clinician to understand the possible risk factors associated with the development of senile cataract and could be helpful in designing a intervention strategy in future.

Association between statin therapy and tendon rupture: a case-control study.

PubMed

Beri, Abhimanyu; Dwamena, Francesca C; Dwamena, Ben A

2009-05-01

Although case reports of a possible association between statin therapy and tendon rupture have been published, no analytical studies exploring this relationship have been reported. We conducted a case-control study using the electronic medical records at Michigan State University from 2002 to 2007 to assess whether statin use is a risk factor for tendon rupture. We compared exposure to statins in 93 cases of tendon rupture with similar exposure in 279 sex- and age-matched controls. Exposure to statins was defined as documentation in the electronic medical record of statin use in the 12 months preceding tendon rupture. For controls, the exposure period was defined as 1 year preceding the last office visit. We used a multivariate logistic regression model, controlling for diabetes, renal disease, rheumatologic disease, and steroid use, to calculate the adjusted odds ratios (ORs). There was no significant difference between cases and controls in the rates of statin use, with either univariate [OR = 1.0, 95% confidence interval (CI) 0.54-1.84] or multivariate analyses (OR = 1.10, 95% CI 0.57-2.13). Based on predetermined subgroup analyses, statin exposure was found to be a significant risk factor for tendon rupture in women (adjusted OR = 3.76, 95% CI 1.11-12.75) but not in men (adjusted OR = 0.66, 95% CI 0.29-1.51). In conclusion, we found no overall association between statin use and tendon rupture, but subgroup analysis suggested that women with tendon rupture were more likely to be on statins.

Tooth eruption sequence and dental crowding: a case-control study

PubMed Central

Moshkelgosha, Vahid; Khosravifard, Negar; Golkari, Ali

2014-01-01

When cases of dental crowding are identified and diagnosed promptly, interceptive orthodontics is particularly successful. Aim: To assess the differences in the eruption sequence of the mandibular canine and first premolar teeth in children with and without dental crowding. Materials and Methods: Children who attended the Shiraz Dental School's orthodontic clinic (Iran) from September to December 2012 were enrolled in this case-control study. Tooth size arch length discrepancy (TSALD) of all 8-10 year olds was calculated from patients’ dental models. Thirty-six children were randomly selected from those with TSALD of equal or less than 4mm (those with crowding). Each selected case was matched for sex and age with another child (as control) with TSALD>−4mm attending the same clinic, in the same time period. The existing panoramic radiographs were traced and the eruption percentages were measured for mandibular canine and first premolar teeth. The mean difference between canine and first premolar eruption percentages was compared between the case and control groups using the SPSS (version PASW 18) software and a paired sample t-test. Results: Canine and first premolar eruption percentages in the case group were 65.82±13.00 and 78.92±10.15 percent, respectively. The mean eruption percentages for canines and first premolars of the control group were 74.12±14.55 and 75.47±11.60 percent, respectively. There was a significant difference in pre-eruptive positions of canine and first premolar teeth in those with moderate to severe crowding when compared to the control group (p<0.001). Conclusion: These findings may improve the early diagnosis of children with high risk of developing moderate to severe crowding during mixed dentition. PMID:25110582

High risk human papillomavirus in the periodontium : A case control study.

PubMed

Shipilova, Anna; Dayakar, Manjunath Mundoor; Gupta, Dinesh

2017-01-01

Human papilloma viruses (HPVs) are small DNA viruses that have been identified in periodontal pocket as well as gingival sulcus. High risk HPVs are also associated with a subset of head and neck carcinomas. It is thought that the periodontium could be a reservoir for HPV. 1. Detection of Human Papilloma virus (HPV) in periodontal pocket as well as gingival of patients having localized chronic periodontitis and gingival sulcus of periodontally healthy subjects. 2. Quantitative estimation of E6 and E7 mRNA in subjects showing presence of HPV3. To assess whether periodontal pocket is a reservoir for HPV. This case-control study included 30 subjects with localized chronic Periodontitis (cases) and 30 periodontally healthy subjects (controls). Two samples were taken from cases, one from periodontal pocket and one from gingival sulcus and one sample was taken from controls. Samples were collected in the form of pocket scrapings and gingival sulcus scrapings from cases and controls respectively. These samples were sent in storage media for identification and estimation of E6/E7 mRNA of HPV using in situ hybridization and flow cytometry. Statistical analysis was done by using, mean, percentage and Chi Square test. A statistical package SPSS version 13.0 was used to analyze the data. P value < 0.05 was considered as statistically significant. pocket samples as well as sulcus samples for both cases and controls were found to contain HPV E6/E7 mRNAInterpretation and. Presence of HPV E6/E7 mRNA in periodontium supports the hypothesis that periodontal tissues serve as a reservoir for latent HPV and there may be a synergy between oral cancer, periodontitis and HPV. However prospective studies are required to further explore this link.

Worker substance use, workplace problems and the risk of occupational injury: a matched case-control study.

PubMed

Spicer, Rebecca S; Miller, Ted R; Smith, Gordon S

2003-07-01

This study examines the tendency toward problem behavior as an explanation for the relationship between problem substance use and occupational injury. The authors used a matched case-control study nested in a cohort of 26,413 workers, in which cases (n = 3,994) were workers suffering an occupational injury. Five controls per case (n = 19,970) were selected from the cohort of workers active on the day of the injury and matched on job type. Conditional logistic regression modeled the association of problem substance use with occupational injury, controlling for problem behaviors and worker characteristics. Problem substance use was indicated indirectly if any of the following were alcohol/drug-involved during the comparison period: Employee Assistance Program visit, excused absence or disciplinary action. Discipline records identified minor (absenteeism) and serious (dishonesty, theft, assault, harassment, disrespect) problem behaviors during the comparison period. The odds of injury among workers with an indicator of problem substance use was 1.35 (p = .015) times greater than the odds among workers without an indicator, controlling for job type and demographics as well as adjusting for exposure. This ratio declined to 1.21 (p = .138) when problem behaviors were also controlled for. Minor and serious problem behaviors were significantly associated with occupational injury (odds ratio [OR] = 1.73, p < .001, and OR = 2.19, p < .001, respectively), controlling for demographics and substance use. The relationship of problem substance use with occupational injury was weak when problem behaviors were controlled for, suggesting that this relationship, observed in previous studies, may be explained by a workers tendency toward problem behaviors. Workplace injury prevention programs should address the expression of problem behaviors as a complement to drug and alcohol deterrent programs.

Sphingolipid metabolism potential in fecal microbiome and bronchiolitis in infants: a case-control study.

PubMed

Hasegawa, Kohei; Stewart, Christopher J; Mansbach, Jonathan M; Linnemann, Rachel W; Ajami, Nadim J; Petrosino, Joseph F; Camargo, Carlos A

2017-07-26

Emerging evidence demonstrated that the structure of fecal microbiome is associated with the likelihood of bronchiolitis in infants. However, no study has examined functional profiles of fecal microbiome in infants with bronchiolitis. In this context, we conducted a case-control study. As a part of multicenter prospective study, we collected stool samples from 40 infants hospitalized with bronchiolitis (cases). We concurrently enrolled 115 age-matched healthy controls. First, by applying 16S rRNA gene sequencing to these 155 fecal samples, we identified the taxonomic profiles of fecal microbiome. Next, based on the taxonomy data, we inferred the functional capabilities of fecal microbiome and tested for differences in the functional capabilities between cases and controls. Overall, the median age was 3 months and 45% were female. Among 274 metabolic pathways surveyed, there were significant differences between bronchiolitis cases and healthy controls for 37 pathways, including lipid metabolic pathways (false discovery rate [FDR] <0.05). Particularly, the fecal microbiome of bronchiolitis cases had consistently higher abundances of gene function related to the sphingolipid metabolic pathways compared to that of controls (FDR <0.05). These pathways were more abundant in infants with Bacteroides-dominant microbiome profile compared to the others (FDR <0.001). On the basis of the predicted metagenome in this case-control study, we found significant differences in the functional potential of fecal microbiome between infants with bronchiolitis and healthy controls. Although causal inferences remain premature, our data suggest a potential link between the bacteria-derived metabolites, modulations of host immune response, and development of bronchiolitis.

The effect of N-acetyl cysteine (NAC) on aluminum phosphide poisoning inducing cardiovascular toxicity: a case-control study.

PubMed

Taghaddosinejad, Fakhreddin; Farzaneh, Esmaeil; Ghazanfari-Nasrabad, Mahdi; Eizadi-Mood, Nastaran; Hajihosseini, Morteza; Mehrpour, Omid

2016-01-01

Aluminum phosphide (AlP) is a very effective indoor and outdoor pesticide. We investigated the effects of N-acetyl cysteine (NAC) on the survival time, hemodynamics, and cardiac biochemical parameters at various time intervals in some cases of AlP poisoning. This research was a case-control study to evaluate 63 AlP poisoned patients during 2010-2012. Patients with cardiovascular complications of AlP to be treated with intravenous NAC plus conventional treatment were considered as the case group and compared with patients who did not receive NAC. NAC infusion was administered to the case group at 300 mg/kg for 20 h. The data gathered included age, sex, heart rate, Systolic blood pressure (SBP), creatine phosphokinase (CPK), creatine kinase MB (CK-MB), and ECG at the admission time and 12, 18, and 24 h after admission. Analysis of repeated measures was performed to check the variability of parameters over time. The mean ages in the case and control groups were 26.65 ± 1.06 (19-37 years) and 28.39 ± 1.11 (18-37 years), respectively (P = 0.266). Most of the patients were female (56.5%). CK-MB means were significantly different between the two groups, but no differences between the other variables were observed. Also, CK-MB, CPK, heart rate, and systolic blood pressure means became significantly different over time (0, 12, 18, and 24 h) in both groups (P < 0.001). NAC prevented sharp heart rate fluctuations in AlP patients in the case group. Regarding the outcomes, 17 patients died (10 patients in the control and 7 patients in the case groups). No side-effects of NAC were observed. Our patients could be managed by the positive role of NAC as the biochemical index of cardiotoxicity was found to elevate in both the case and control groups. Therefore, for the management protocol optimization, NAC evaluation should be done in further cases.

Potential Psychosocial Risk Factors for Chronic TMD: Descriptive Data and Empirically Identified Domains from the OPPERA Case-Control Study

PubMed Central

Fillingim, Roger B.; Ohrbach, Richard; Greenspan, Joel D.; Knott, Charles; Dubner, Ronald; Bair, Eric; Baraian, Cristina; Slade, Gary D.; Maixner, William

2011-01-01

Case-control studies have consistently associated psychosocial factors with chronic pain in general, and with temporomandibular disorders (TMD) specifically. Moreover, a handful of prospective studies suggest that pre-existing psychosocial characteristics represent risk factors for new onset TMD. The current study presents psychosocial findings from the baseline case-control study of the Orofacial Pain Prospective Evaluation and Risk Assessment (OPPERA) cooperative agreement. For this study, 1,633 TMD-free controls and 185 TMD cases completed a battery of psychosocial instruments assessing general psychosocial adjustment and personality, affective distress, psychosocial stress, somatic awareness, and pain coping and catastrophizing. In bivariate and demographically-adjusted analyses, odds of TMD were associated with higher levels of psychosocial symptoms, affective distress, somatic awareness, and pain catastrophizing. Among controls, significant gender and ethnic group differences in psychosocial measures were observed, consistent with previous findings. Principal component analysis was undertaken to identify latent constructs revealing four components: stress and negative affectivity, global psychosocial symptoms, passive pain coping, and active pain coping. These findings provide further evidence of associations between psychosocial factors and TMD. Future prospective analyses in the OPPERA cohort will determine if the premorbid presence of these psychosocial factors predicts increased risk for developing new-onset TMD. PMID:22074752

Co-Prevalence of Tremor with Spasmodic Dysphonia: A Case-Control Study

PubMed Central

White, Laura; Klein, Adam; Hapner, Edie; Delgaudio, John; Hanfelt, John; Jinnah, H. A.; Johns, Michael

2011-01-01

OBJECTIVES/HYPOTHESIS The aim of this study was to define the co-prevalence of tremor with spasmodic dysphonia (SD). STUDY DESIGN A single institution prospective, case-control study was performed from May 2010 to July 2010. METHODS Consecutive patients with SD (cases) and other voice disorders (controls) were enrolled prospectively. Each participant underwent a voice evaluation and an evaluation for tremor. RESULTS 146 voice disorder controls and 128 patients with SD were enrolled. 26% of patients with SD had vocal tremor, 21% had non-vocal tremor. Patients with SD were 2.8 times more likely to have co-prevalent tremor than the control group (OR = 2.81; 95% CI, 1.55 to 5.08) and only 35% of patients with SD had been seen by a neurologist for the evaluation of dystonia and tremor. CONCLUSIONS Tremor is highly prevalent in patients with SD. It is important for each patient diagnosed with SD to undergo an evaluation for tremor, this is especially important in patients diagnosed with vocal tremor. Level of evidence 3b. PMID:21792965

Can iridology detect susceptibility to cancer? A prospective case-controlled study.

PubMed

Münstedt, Karsten; El-Safadi, Samer; Brück, Friedel; Zygmunt, Marek; Hackethal, Andreas; Tinneberg, Hans-Rudolf

2005-06-01

This prospective case-control study aimed to investigate the value of iridology as a diagnostic tool in detecting some common cancers. One hundred ten (110) subjects were enrolled in the study: 68 subjects had histologically proven cancers of the breast, ovary, uterus, prostate, or colorectum, and 42 were control subjects. All subjects were examined by an experienced practitioner of iridology, who was unaware of their gender or medical details. He was allowed to suggest up to five diagnoses for each subject and his results were then compared with each subject's medical diagnosis to determine the accuracy of iridology in detecting malignancy. Iridology identified the correct diagnosis in only 3 cases (sensitivity, 0.04). Iridology was of no value in diagnosing the cancers investigated in this study.

The Upper Midwest Health Study: industry and occupation of glioma cases and controls.

PubMed

Ruder, Avima M; Waters, Martha A; Carreón, Tania; Butler, Mary A; Calvert, Geoffrey M; Davis-King, Karen E; Waters, Kathleen M; Schulte, Paul A; Mandel, Jack S; Morton, Roscoe F; Reding, Douglas J; Rosenman, Kenneth D

2012-09-01

Understanding glioma etiology requires determining which environmental factors are associated with glioma. Upper Midwest Health Study case-control participant work histories collected 1995-1998 were evaluated for occupational associations with glioma. "Exposures of interest" from our study protocol comprise our a priori hypotheses. Year-long or longer jobs for 1,973 participants were assigned Standard Occupational Classifications (SOC) and Standard Industrial Classifications (SIC). The analysis file includes 8,078 SIC- and SOC-coded jobs. For each individual, SAS 9.2 programs collated employment with identical SIC-SOC coding. Distributions of longest "total employment duration" (total years worked in jobs with identical industry and occupation codes, including multiple jobs, and non-consecutive jobs) were compared between cases and controls, using an industrial hygiene algorithm to group occupations. Longest employment duration was calculated for 780 cases and 1,156 controls. More case than control longest total employment duration was in the "engineer, architect" occupational group [16 cases, 10 controls, odds ratio (OR) 2.50, adjusted for age group, sex, age and education, 95% confidence interval (CI) 1.12-5.60]. Employment as a food processing worker [mostly butchers and meat cutters] was of borderline significance (27 cases, 21 controls, adjusted OR: 1.78, CI: 0.99-3.18). Among our exposures of interest work as engineers or as butchers and meat cutters was associated with increased glioma risk. Significant associations could be due to chance, because of multiple comparisons, but similar findings have been reported for other glioma studies. Our results suggest some possible associations but by themselves could not provide conclusive evidence. Copyright © 2012 Wiley Periodicals, Inc.

Dietary food groups intake and cooking methods associations with pancreatic cancer: a case-control study.

PubMed

Ghorbani, Zeinab; Hekmatdoost, Azita; Zinab, Hassan Eini; Farrokhzad, Solmaz; Rahimi, Roya; Malekzadeh, Reza; Pourshams, Akram

2015-05-01

The role of dietary habits in the etiology of pancreatic cancer (PC) has not yet been well elucidated. The aim of the present study was to examine the association of the frequency of different food groups' intake and their cooking methods with PC risk based on a well-designed case-control study. A case-control study including 307 PC patients and 322 controls referred to four tertiary endosonography centers was conducted from January 2011 to January 2014 to compare the frequency intake of different food items and their cooking methods between cases and controls. After adjustment for gender, age, body mass index, years of education, diabetes and alcohol history, smoking status, and opium use, a significant direct relationship was observed between PC risk and intake frequency (time/week) of bread (OR = 1.50; 95 % CI 1.05-2.13; p-value 0.024), rice (OR = 2.10; 95 % CI 1.15-3.82; p for trend 0.034), and red meat (OR = 2.25; 95 % CI 1.22-4.14; p for trend 0.033) (time/day), when comparing the highest category of intake frequency with the lowest, while increasing frequency of fish consumption was associated with a lower risk of PC (OR = 0.93; 95 % CI0.59-1.47; p for trend 0.009). Increasing consumption of barbecuing red meat and deep fried vegetables was associated with 67 % and 70 % increased risk of PC (p-value 0.025 and 0.006, respectively). Our results indicate that increased frequency of intake of bread, rice, and red meat (especially barbecued) and deep fried vegetables can aggregate PC risk, while increased frequency of fish consumption can protect against PC. However, more studies are still needed.

Traffic rule violations of private bus drivers and bus crashes in Sri Lanka: a case-control study.

PubMed

Jayatilleke, Achala Upendra; Poudel, Krishna C; Nakahara, Shinji; Dharmaratne, Samath D; Jayatilleke, Achini Chinthika; Jimba, Masamine

2010-06-01

To explore the association between self-reported traffic rule violations of private sector bus drivers and bus crashes in the Kandy district, Sri Lanka. We carried out a case-control study from August to September 2006. Cases were all the private bus drivers registered in the Kandy district and involved in crashes reported to the police between November 2005 and April 2006 (n = 63). We included two control groups: the private bus drivers working on the same routes of the cases (n = 90; matched controls) and the drivers selected randomly from the other routes of the district (n = 111; unmatched controls). We used a self-administered questionnaire to collect data on the self-reported traffic rule violations and analyzed the association between the self-reported traffic rule violations and crashes using logistic regression. The following variables showed significant associations with private bus crashes: illegal overtaking (matched controls, adjusted odds ratio [AOR] = 14.78, unmatched controls, AOR = 1.04), taking passengers outside the bus bays (matched controls, AOR = 3.96, unmatched controls, AOR = 2.29), and overloading (matched controls, AOR = 10.26, unmatched controls, AOR = 1.93). However, we did not observe an association between high-speed driving and bus crashes matched controls, AOR = 1.22, unmatched controls, AOR = 0.81. Traffic rule violations, such as illegal overtaking, overloading, and taking passengers outside the bus bays, are significant risk factors for private bus crashes in Sri Lanka.

Effectiveness of pneumococcal vaccination for elderly people in Catalonia, Spain: a case-control study.

PubMed

Dominguez, Angela; Salleras, Lluis; Fedson, David S; Izquierdo, Conchita; Ruiz, Laura; Ciruela, Pilar; Fenoll, Asuncion; Casal, Julio

2005-05-01

Observational studies offer an approach to evaluating the effectiveness of vaccination programs. We evaluated the effectiveness of a 23-valent pneumococcal vaccination program for elderly people in Catalonia, Spain, in a matched-set case-control study. We identified 149 cases of invasive pneumococcal disease among patients aged > or =65 years who were hospitalized in 12 large hospitals in Catalonia during the period of 1 January 2001 through 31 March 2002. We selected 2 hospital control patients and 1 outpatient control subject for each case patient, matching on the basis of age and underlying medical conditions. We obtained their pneumococcal vaccination histories and used conditional logistic regression to determine effectiveness of vaccination. Among all 149 cases of invasive pneumococcal disease, 131 (87.9%) were caused by vaccine or vaccine-related serotypes. In the adjusted analysis, overall effectiveness of vaccination against infections due to all serotypes was 70% (95% confidence interval [CI], 48%-82%). Among immunocompetent subjects with or without high-risk conditions, effectiveness of vaccination was 76% (95% CI, 51%-88%), but among immunocompromised subjects it was 50% (95% CI, -44% to 82%). Among subjects with infections due to vaccine or vaccine-related serotypes, effectiveness of vaccination was 72% (95% CI, 50%-85%) overall and 78% (95% CI, 50%-90%) in those who were immunocompetent, but it was only 46% (95% CI, -54% to 81%) in those who were immunocompromised. Overall effectiveness of vaccination was 65% (95% CI, 35%-81%) during the noninfluenza period. Pneumococcal vaccination was effective in preventing invasive pneumococcal disease among all elderly persons in Catalonia. Effectiveness was greater in immunocompetent persons, most of whom had underlying high-risk conditions. The number of subjects was too small to determine whether vaccination was effective in those who were immunocompromised.

Fructose malabsorption in people with and without gout: A case-control study.

PubMed

Batt, Caitlin; Fanning, Niamh; Drake, Jill; Frampton, Christopher; Gearry, Richard B; Stamp, Lisa K

2017-10-01

Higher fructose intake has been associated with hyperuricaemia and gout. Some individuals malabsorb fructose in the small intestine. The aims of this study were to determine the rate of fructose malabsorption and the effects of gout and fructose malabsorption on serum urate in people with and without gout. A total of 100 people with gout (cases) were age and gender matched with one control without gout. After a low fructose diet, fructose malabsorption was measured using a hydrogen and methane breath test with a 35g fructose load. In a subgroup of 35 cases and 35 controls, serum urate response to the fructose load over 240 minutes was measured. There was no significant difference in the rate of fructose malabsorption between cases and controls (48% vs. 52%; p = 0.67). Cases had a significantly lower mean (SEM) serum urate cumulative incremental concentration from baseline-240 minutes (iAUC 0-240 ) compared to controls 0.97 (0.56) vs. 4.78 (0.55); p < 0.001. C max was significantly lower in cases compared to controls [0.38 (0.003) vs. 0.40 (0.003); p < 0.001]. 95% of cases were receiving allopurinol. There was no significant difference between iAUC 0-240 or C max for malabsorbers compared to normal absorbers irrespective of case-control status. The mean (SEM) increase in serum urate between baseline and 30 minutes was 0.04 (0.004)mmol/l in the controls compared to 0.009 (0.002) in the cases (p < 0.001). The rates of fructose malabsorption are similar in people with and without gout. Allopurinol inhibits the increase in serum urate induced by a fructose load suggesting that people with gout receiving allopurinol may not need to restrict dietary intake of fructose. Copyright © 2017 Elsevier Inc. All rights reserved.

The Diesel Exhaust in Miners study: a nested case-control study of lung cancer and diesel exhaust.

PubMed

Silverman, Debra T; Samanic, Claudine M; Lubin, Jay H; Blair, Aaron E; Stewart, Patricia A; Vermeulen, Roel; Coble, Joseph B; Rothman, Nathaniel; Schleiff, Patricia L; Travis, William D; Ziegler, Regina G; Wacholder, Sholom; Attfield, Michael D

2012-06-06

Most studies of the association between diesel exhaust exposure and lung cancer suggest a modest, but consistent, increased risk. However, to our knowledge, no study to date has had quantitative data on historical diesel exposure coupled with adequate sample size to evaluate the exposure-response relationship between diesel exhaust and lung cancer. Our purpose was to evaluate the relationship between quantitative estimates of exposure to diesel exhaust and lung cancer mortality after adjustment for smoking and other potential confounders. We conducted a nested case-control study in a cohort of 12 315 workers in eight non-metal mining facilities, which included 198 lung cancer deaths and 562 incidence density-sampled control subjects. For each case subject, we selected up to four control subjects, individually matched on mining facility, sex, race/ethnicity, and birth year (within 5 years), from all workers who were alive before the day the case subject died. We estimated diesel exhaust exposure, represented by respirable elemental carbon (REC), by job and year, for each subject, based on an extensive retrospective exposure assessment at each mining facility. We conducted both categorical and continuous regression analyses adjusted for cigarette smoking and other potential confounding variables (eg, history of employment in high-risk occupations for lung cancer and a history of respiratory disease) to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Analyses were both unlagged and lagged to exclude recent exposure such as that occurring in the 15 years directly before the date of death (case subjects)/reference date (control subjects). All statistical tests were two-sided. We observed statistically significant increasing trends in lung cancer risk with increasing cumulative REC and average REC intensity. Cumulative REC, lagged 15 years, yielded a statistically significant positive gradient in lung cancer risk overall (P (trend) = .001); among heavily

Suicidal drug overdose in patients with systemic lupus erythematosus, a nationwide population-based case-control study.

PubMed

Tang, K T; Lin, C H; Chen, H H; Chen, Y H; Chen, D Y

2016-02-01

A four-fold increase of suicide mortality has been demonstrated in systemic lupus erythematosus (SLE) patients. Prior studies showed that the most common method of suicide attempts in SLE patients involves drug overdose. Therefore, we conducted a nationwide population-based case-control study to elucidate factors associated with drug overdose as suicide attempt in SLE patients. This study was based on the National Health Insurance Research Database in Taiwan. We identified all SLE patients from January 1, 2000 to December 31, 2010. Patients who had suicidal drug overdose (SDO) were selected as cases while age- and gender-matched patients who did not have SDO were selected as controls. The incidence rate of SDO in SLE patients was 291 cases per 100,000 person-years, higher than that in the general population (160 cases per 100,000 person-years). In a multivariate logistic regression analysis, we observed that SDO was associated with psychiatric disorders such as depressive disorders (odds ratio: 8.36, 95% confidence interval (CI): 5.60-12.48) and insomnia (odds ratio: 2.71, 95% CI: 1.73-4.25), and lower monthly income (odds ratios: 2.74 to 3.50) in SLE patients. SDO is associated with psychiatric disorders such as depressive disorders and insomnia, and lower monthly income in SLE patients. © The Author(s) 2015.

Modified metabolic syndrome and second cancers in women: A case control study.

PubMed

Ortiz-Mendoza, Carlos-Manuel; Pérez-Chávez, Ernesto; Fuente-Vera, Tania-Angélica De-la

2016-01-01

According to some studies, the metabolic syndrome causes diverse primary cancers; however, there is no evidence about metabolic syndrome impact on second cancers development in women. To find out the implication of the modified metabolic syndrome in women with second cancers. This was a case-control study, at a general hospital in Mexico City, in women with second cancers (cases) and age-matched women with only one neoplasm (controls). The analysis comprised: Tumor (s), anthropometric features, and body mass index (BMI); moreover, presence of diabetes mellitus, hypertension, and fasting serum levels of total cholesterol, triglycerides and glucose. The sample was of nine cases and 27 controls. In cases, the metabolic syndrome (diabetes mellitus or glucose > 99 mg/dL + hypertension or blood pressure ≥ 135/85 mm Hg + triglycerides > 149 mg/dL or BMI ≥ 30 kg/m 2 ) was more frequent (odds ratio 20.8, 95% confidence interval: 1.9-227.1). Our results suggest that in women, the modified metabolic syndrome may be a risk factor for second cancers.

A case-control study of Yersinia enterocolitica infections in Auckland.

PubMed

Satterthwaite, P; Pritchard, K; Floyd, D; Law, B

1999-10-01

To identify major risk factors for Yersinia enterocolitica (YE) and identify measures to reduce YE infections. A prospective case control study, group age matched, using 186 cases of YE identified by community pathology laboratories and 379 randomly selected controls. Conducted between April 1995 and June 1996 in Auckland, New Zealand. Face-to-face interviews used a standardised questionnaire examining exposures to factors potentially associated with YE infections including untreated water, unreticulated sewerage, consumption of selected foods, selected food handling practices and socio-demographic factors. Multivariate logistic regression was used to calculate adjusted odds ratios for the potential risk factors. Population attributable risk (PAR) was calculated for significant exposures. Having more than two people living in the home was more common among cases than controls (OR = 2.2). Town supply water (OR = 0.2), reticulated sewerage (OR = 0.34) and looking after a young child (OR = 0.51) were significantly less common. Of the meats, only pork (OR = 1.34) had a higher consumption rate, while bacon (OR = 0.75) and smallgoods (OR = 0.73) were consumed less frequently by cases than controls. Eating food from a sandwich bar was more frequent among cases (OR = 1.18). Fruit and vegetable consumption was marginally less (OR = 0.98). The population attributable risk of these factors was 0.89, implying that 89% of YE would be eliminated if adverse exposures were removed. The risk of YE illness is increased by contact with untreated water, unreticulated sewerage and consumption of pork. Investigation of non-town water supply, informal sewerage systems and methods of preparation and consumption of pork are recommended to determine how YE enters the human food chain.

A case-control study of airways obstruction among construction workers.

PubMed

Dement, John; Welch, Laura; Ringen, Knut; Quinn, Patricia; Chen, Anna; Haas, Scott

2015-10-01

While smoking is the major cause of chronic obstructive pulmonary disease (COPD), occupational exposures to vapors, gases, dusts, and fumes (VGDF) increase COPD risk. This case-control study estimated the risk of COPD attributable to occupational exposures among construction workers. The study population included 834 cases and 1243 controls participating in a national medical screening program for older construction workers between 1997 and 2013. Qualitative exposure indices were developed based on lifetime work and exposure histories. Approximately 18% (95% CI = 2-24%) of COPD risk can be attributed to construction-related exposures, which are additive to the risk contributed by smoking. A measure of all VGDF exposures combined was a strong predictor of COPD risk. Construction workers are at increased risk of COPD as a result of broad and complex effects of many exposures acting independently or interactively. Control methods should be implemented to prevent worker exposures, and smoking cessation should be promoted. © 2015 The Authors. American Journal of Industrial Medicine Published by Wiley Periodicals, Inc.

Case-control study of genus-beta human papillomaviruses in plucked eyebrow hairs and cutaneous squamous cell carcinoma.

PubMed

Iannacone, Michelle R; Gheit, Tarik; Pfister, Herbert; Giuliano, Anna R; Messina, Jane L; Fenske, Neil A; Cherpelis, Basil S; Sondak, Vernon K; Roetzheim, Richard G; Silling, Steffi; Pawlita, Michael; Tommasino, Massimo; Rollison, Dana E

2014-05-01

Cutaneous human papillomaviruses (HPV) have been reported in cutaneous squamous cell carcinoma (SCC). We conducted a clinic-based case-control study to investigate the association between genus-beta HPV DNA in eyebrow hairs (EBH) and SCC. EBH from 168 SCC cases and 290 controls were genotyped for genus-beta HPV DNA. SCC tumors from a subset of cases (n = 142) were also genotyped. Viral load was determined in a subset of specimens positive for a single HPV type. Associations with SCC were estimated by odds ratios (OR) and 95% confidence intervals (CI) adjusted for age and sex using logistic regression. Statistical tests were two-sided. EBH DNA prevalence was greater in cases (87%) than controls (73%) (p < 0.05), and the association with SCC increased with the number of HPV types present, (≥ 4 types vs. HPV-negative: OR = 2.02, 95% CI = 1.07-3.80; p(trend) = 0.02). Type-specific associations were observed between SCC and DNA in EBH for HPV23 (OR = 1.90, 95% CI = 1.10-3.30) and HPV38 (OR = 1.84, 95% CI = 1.04-3.24). Additionally, when compared with the controls, the DNA prevalence in EBH was significantly higher among cases for 11 of the 25 genus-beta types tested, when accounting for DNA for the same HPV type in the tumor (ORs = 3.44-76.50). Compared to controls, the mean viral DNA load in EBH among the selected cases was greater for HPV5, HPV8 and HPV24, but lower for HPV38. SCC cases were more likely than controls to have HPV DNA+ EBH for single and multiple HPV types, providing additional support for the potential role of genus-beta HPV infections in SCC development. © 2013 UICC.

Breast cancer risk and genetic ancestry: a case-control study in Uruguay.

PubMed

Bonilla, Carolina; Bertoni, Bernardo; Hidalgo, Pedro C; Artagaveytia, Nora; Ackermann, Elizabeth; Barreto, Isabel; Cancela, Paula; Cappetta, Mónica; Egaña, Ana; Figueiro, Gonzalo; Heinzen, Silvina; Hooker, Stanley; Román, Estela; Sans, Mónica; Kittles, Rick A

2015-01-01

Uruguay exhibits one of the highest rates of breast cancer in Latin America, similar to those of developed nations, the reasons for which are not completely understood. In this study we investigated the effect that ancestral background has on breast cancer susceptibility among Uruguayan women. We carried out a case-control study of 328 (164 cases, 164 controls) women enrolled in public hospitals and private clinics across the country. We estimated ancestral proportions using a panel of nuclear and mitochondrial ancestry informative markers (AIMs) and tested their association with breast cancer risk. Nuclear individual ancestry in cases was (mean ± SD) 9.8 ± 7.6% African, 13.2 ± 10.2% Native American and 77.1 ± 13.1% European, and in controls 9.1 ± 7.5% African, 14.7 ± 11.2% Native American and 76.2 ± 14.2% European. There was no evidence of a difference in nuclear or mitochondrial ancestry between cases and controls. However, European mitochondrial haplogroup H was associated with breast cancer (OR = 2.0; 95% CI 1.1, 3.5). We have not found evidence that overall genetic ancestry differs between breast cancer patients and controls in Uruguay but we detected an association of the disease with a European mitochondrial lineage, which warrants further investigation.

On estimation of time-dependent attributable fraction from population-based case-control studies.

PubMed

Zhao, Wei; Chen, Ying Qing; Hsu, Li

2017-09-01

Population attributable fraction (PAF) is widely used to quantify the disease burden associated with a modifiable exposure in a population. It has been extended to a time-varying measure that provides additional information on when and how the exposure's impact varies over time for cohort studies. However, there is no estimation procedure for PAF using data that are collected from population-based case-control studies, which, because of time and cost efficiency, are commonly used for studying genetic and environmental risk factors of disease incidences. In this article, we show that time-varying PAF is identifiable from a case-control study and develop a novel estimator of PAF. Our estimator combines odds ratio estimates from logistic regression models and density estimates of the risk factor distribution conditional on failure times in cases from a kernel smoother. The proposed estimator is shown to be consistent and asymptotically normal with asymptotic variance that can be estimated empirically from the data. Simulation studies demonstrate that the proposed estimator performs well in finite sample sizes. Finally, the method is illustrated by a population-based case-control study of colorectal cancer. © 2017, The International Biometric Society.

Association of ALOX5AP with ischemic stroke: a population-based case-control study.

PubMed

Kaushal, Ritesh; Pal, Prodipto; Alwell, Kathleen; Haverbusch, Mary; Flaherty, Matthew; Moomaw, Charles; Sekar, Padmini; Kissela, Brett; Kleindorfer, Dawn; Chakraborty, Ranajit; Broderick, Joseph; Deka, Ranjan; Woo, Daniel

2007-06-01

Arachidonate 5-lipoxygenase activating protein (ALOX5AP) has been reported to demonstrate linkage and association with ischemic stroke and myocardial infarction. However, replication studies have been conflicting and to date, a significant proportion of blacks have not been studied. We prospectively recruited cases of ischemic stroke from all 16 hospitals in the Greater Cincinnati/Northern Kentucky region and demographically matched them to stroke-free population-based controls. Single nucleotide polymorphisms (SNPs) were selected based on association with ischemic stroke in prior studies. Allelic, genotypic and haplotypic association testing was performed using HAPLOVIEW. Multiple logistic regression was used to control for the presence of traditional risk factors including hypertension, diabetes, hypercholesterolemia and smoking. A total of 357 cases and 482 controls were genotyped. The SNPs, rs9579646 and rs4769874 were found to be significantly associated at both allelic (P=0.019 and P<10(-4), respectively) and genotypic level with ischemic stroke among whites after correction for multiple testing. Haplotype association was identified with ischemic stroke as well as ischemic stroke subtypes among whites. Although an overall haplotype association with ischemic stroke was identified among blacks no evidence of association among individual haplotypes, alleles or genotypes were observed. Allele frequencies for the SNPs examined were markedly different among whites and blacks. In conclusion, we report significant association of variants of ALOX5AP with ischemic stroke and ischemic stroke subtypes among whites. No significant association was identified among blacks.

Mental illness, poverty and stigma in India: a case-control study.

PubMed

Trani, Jean-Francois; Bakhshi, Parul; Kuhlberg, Jill; Narayanan, Sreelatha S; Venkataraman, Hemalatha; Mishra, Nagendra N; Groce, Nora E; Jadhav, Sushrut; Deshpande, Smita

2015-02-23

To assess the effect of experienced stigma on depth of multidimensional poverty of persons with severe mental illness (PSMI) in Delhi, India, controlling for gender, age and caste. Matching case (hospital)-control (population) study. University Hospital (cases) and National Capital Region (controls), India. A case-control study was conducted from November 2011 to June 2012. 647 cases diagnosed with schizophrenia or affective disorders were recruited and 647 individuals of same age, sex and location of residence were matched as controls at a ratio of 1:2:1. Individuals who refused consent or provided incomplete interview were excluded. Higher risk of poverty due to stigma among PSMI. 38.5% of PSMI compared with 22.2% of controls were found poor on six dimensions or more. The difference in multidimensional poverty index was 69% between groups with employment and income of the main contributors. Multidimensional poverty was strongly associated with stigma (OR 2.60, 95% CI 1.27 to 5.31), scheduled castes/scheduled tribes/other backward castes (2.39, 1.39 to 4.08), mental illness (2.07, 1.25 to 3.41) and female gender (1.87, 1.36 to 2.58). A significant interaction between stigma, mental illness and gender or caste indicates female PSMI or PSMI from 'lower castes' were more likely to be poor due to stigma than male controls (p<0.001) or controls from other castes (p<0.001). Public stigma and multidimensional poverty linked to SMI are pervasive and intertwined. In particular for low caste and women, it is a strong predictor of poverty. Exclusion from employment linked to negative attitudes and lack of income are the highest contributors to multidimensional poverty, increasing the burden for the family. Mental health professionals need to be aware of and address these issues. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Risk factors for idiopathic intracranial hypertension in men: a case-control study

PubMed Central

Fraser, J. Alexander; Bruce, Beau B.; Rucker, Janet; Fraser, Lisa-Ann; Atkins, Edward J.; Newman, Nancy J.; Biousse, Valérie

2009-01-01

Objective To identify risk factors for idiopathic intracranial hypertension (IIH) in men Design Case-control study. A 96-item telephone questionnaire, answered retrospectively, with cases recalling at the age of their diagnosis and controls recalling at the age of their corresponding case's diagnosis. Setting Outpatient clinics in two US tertiary care centers Participants The characteristics of 24 men with IIH were compared to those of 48 controls matched for sex, age, race, and World Health Organization body mass index (BMI) category. Main Outcome Measures Two previously validated questionnaires: the ADAM (Androgen Deficiency in Aging Males) questionnaire for testosterone deficiency and the Berlin questionnaire for obstructive sleep apnea (OSA), embedded within the telephone questionnaire. Analysis with Mantel-Haenszel odds ratios and mixed-effects logistic regression models accounted for matching. Results Cases and controls had similar enrollment matching characteristics. Although matching was successful by BMI category, there was a small difference between BMI values of cases and controls (cases: median 31.7, controls: median 29.9; p=0.03). After adjustment by BMI value, men with IIH were significantly more likely than controls to have a positive ADAM questionnaire for testosterone deficiency (OR: 17.4, 95% CI: 5.6-54.5; p<0.001) and significantly more likely to have either a positive Berlin questionnaire for OSA or history of diagnosed OSA (OR: 4.4, 95% CI: 1.5-12.9; p=0.03). Conclusions Men with IIH are more likely than controls to have symptoms associated with testosterone deficiency and OSA. These associations suggest a possible role for sex hormones and OSA in the pathogenesis of IIH in men. PMID:19945715

Risk factors for unintentional poisoning in children aged 1-3 years in NSW Australia: a case-control study.

PubMed

Schmertmann, Marcia; Williamson, Ann; Black, Deborah; Wilson, Leigh

2013-05-24

Unintentional poisoning in young children is an important public health issue. Age pattern studies have demonstrated that children aged 1-3 years have the highest levels of poisoning risk among children aged 0-4 years, yet little research has been conducted regarding risk factors specific to this three-year age group and the methodologies employed varied greatly. The purpose of the current study is to investigate a broad range of potential risk factors for unintentional poisoning in children aged 1-3 years using appropriate methodologies. Four groups of children, one case group (children who had experienced a poisoning event) and three control groups (children who had been 'injured', 'sick' or who were 'healthy'), and their mothers (mother-child dyads) were enrolled into a case-control study. All mother-child dyads participated in a 1.5-hour child developmental screening and observation, with mothers responding to a series of questionnaires at home. Data were analysed as three case-control pairs with multivariate analyses used to control for age and sex differences between child cases and controls. Five risk factors were included in the final multivariate models for one or more case-control pairs. All three models found that children whose mothers used more positive control in their interactions during a structured task had higher odds of poisoning. Two models showed that maternal psychiatric distress increased poisoning risk (poisoning-injury and poisoning-healthy). Individual models identified the following variables as risk factors: less proximal maternal supervision during risk taking activities (poisoning-injury), medicinal substances stored in more accessible locations in bathrooms (poisoning-sick) and lower total parenting stress (poisoning-healthy). The findings of this study indicate that the nature of the caregiver-child relationship and caregiver attributes play an important role in influencing poisoning risk. Further research is warranted to explore the

IgM-monoclonal gammopathy neuropathy and tremor: A first epidemiologic case control study

PubMed Central

Ahlskog, Matthew C.; Kumar, Neeraj; Mauermann, Michelle L.; Klein, Christopher J.

2012-01-01

Introduction Small case series suggest tremor occurs frequently in IgM-monoclonal gammopathy of undetermined significance (IgM-MGUS) neuropathy. Epidemiologic study to confirm this association is lacking. Whether the neuropathy or another remote IgM-effect is causal remains unsettled. Materials and methods An IgM-MGUS neuropathy case cohort (n=207) was compared to age, gender, and neuropathy impairment score (NIS) matched, other-cause neuropathy controls (n=414). Tremor details were extracted from structured neurologic evaluation. All patients underwent nerve conductions. Results Tremor occurrence was significantly higher in IgM-MGUS case cohort (29%) than in control cohort (9.2%) (p=0.001). In IgM-MGUS cases, tremor was associated with worse NIS (p=0.025) and demyelinating nerve conductions (p=0.020), but 11 of 60 (18%) IgM-MGUS cases with tremor had axonal neuropathy. In other-cause neuropathy controls, tremor was associated with axonal nerve conductions (p=0.03) but not with NIS severity (p=0.57). Tremor occurrence associated with older age in controls, (p=0.004) but not in IgM-MGUS cases (p=0.272). Most IgM-MGUS tremor cases (49/60) had a postural-kinetic tremor, 8 had rest tremor, 3 had mixed rest-action. Alternative causes of tremor was identified in 42% of IgM-MGUS cases, the most common type is inherited essential tremor 6/60 (p=0.04). Conclusions This first epidemiologic case-control study validates association between IgM-MGUS neuropathy and tremor. Among IgM-MGUS neuropathy cases, severity as well as type of neuropathy (demyelinating over axonal) correlated with tremor occurrence. IgM-MGUS paraproteinemia may increase tremor expression in persons recognized with common other risk factors for tremor. PMID:22475624

Rubella in Sub-Saharan Africa and sensorineural hearing loss: a case control study.

PubMed

Caroça, Cristina; Vicente, Vera; Campelo, Paula; Chasqueira, Maria; Caria, Helena; Silva, Susana; Paixão, Paulo; Paço, João

2017-02-01

Rubella infection can affect several organs and cause birth defects that are responsible for congenital rubella syndrome (CRS). Congenital hearing loss is the most common symptom of this syndrome, occurring in approximately 60% of CRS cases. Worldwide, over 100 000 babies are born with CRS every year. There is no specific treatment for rubella, but the disease is preventable by vaccination. Since 1969, the rubella vaccine has been implemented in many countries, but in Africa, only a few countries routinely immunize against rubella. The aim of this study was to estimate the rate of infection from the wild-type rubella virus in São Tomé and Príncipe by determining rubella seroprevalence with a DBS method. The goal of this study was to reinforce the need for implementation of the rubella vaccine in this country. As secondary objectives, the validation of a DBS method was first attempted and an association between seroprevalence and hearing loss was assessed. We collected samples from individuals observed during humanitarian missions in São Tomé and Príncipe. All individuals underwent an audiometric evaluation, and a drop of blood was collected for the dried blood spot (DBS). We define two groups: the case group (individuals with unilateral or bilateral hearing loss (HL)) and the control group (individuals with two normal ears). Patients were excluded if they suffered from conductive HL, if they showed evidence of possible causes of HL, if they had developmental delay or if they refused to participate in the study. Among the 315 subjects, we found 64.1% individuals with IgG for the rubella virus, 32.1% without immunity for the rubella virus and 3.8% who were borderline. In the control group, 62.6% were positive for the rubella IgG, whereas in the case group, 72% were positive. Analyzing both groups, with ages ranging from 2 to 14 years of age and from 15 to 35 years of age, we found a seroprevalence of 50.3% to rubella in the younger group and 82.1% in the

Gender Differences in Hiccup Patients: Analysis of Published Case Reports and Case-Control Studies.

PubMed

Lee, Gyeong-Won; Kim, Rock Bum; Go, Se Il; Cho, Hyun Seop; Lee, Seung Jun; Hui, David; Bruera, Eduardo; Kang, Jung Hun

2016-02-01

Although sporadic male predominance in hiccup patients has been reported, the association between gender differences and triggering factors has rarely been evaluated in patients with hiccups. The aim of this study was to investigate whether gender differences exist in hiccup patients by analyzing all previously published hiccup literature containing gender and etiology information. Published literature on this topic was identified using a standardized search strategy in the PubMed, SCOPUS, and CINAHL electronic databases. The literature search included studies published from January 1990 to December 2013. Searches were limited to English-language publications. Of 476 identified studies, 318 studies were eligible including eight case-control studies that contained nonhiccup control groups. Triggering factors for hiccups were categorized into two types: central nervous system (CNS) and non-CNS causes. Odds ratios (ORs) were calculated for the eight case-control studies and event rates for the other studies by meta-analysis. In addition, gender differences and mean ages were analyzed for the case studies. Pooled OR was 2.42 (95% confidence interval [CI] 1.40-4.17) with inclination for male predominance. Subgroup analysis by cause showed clear male predominance in the non-CNS type with OR of 11.72 (95% CI 3.16-43.50), whereas indistinct in the CNS type with OR of 1.74 (95% CI 0.95-3.16). Of the remaining 310 studies with 864 patients, previous findings were consistent. Male predominance was consistent in non-CNS (85.1%, 95% CI 78.2-90.2) and unknown origin (82.2%, 95% CI 75.8-87.2) patients, whereas mitigating the sex discrepancy in those with CNS origin (65.8%, 95% CI 53.1-76.5). We demonstrated male predominance in hiccup patients. This gender difference for hiccups was more pronounced in patients with non-CNS causes, whereas indistinct in patients with CNS causes. Copyright © 2016 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All

Association between Diabetes and Risk of Aortic Dissection: A Case-Control Study in a Chinese Population.

PubMed

He, Xingwei; Liu, Xintian; Liu, Wanjun; Wang, Bei; Liu, Yujian; Li, Zhuxi; Wang, Tao; Tan, Rong; Gao, Bo; Zeng, Hesong

2015-01-01

It is well-recognized that diabetes represents a powerful independent risk factor for cardiovascular diseases. However, very few studies have investigated the relationship between diabetes and risk of aortic dissection (AD). The aim of this case-control study was to evaluate the association between diabetes and risk of AD in Chinese population. A hospital-based case-control study, consisting of 2160 AD patients and 4320 controls, was conducted in a Chinese population. Demographic, clinical characteristics and risk factors were collected. Diabetes rate of patients with overall AD, Stanford type A AD and type B AD group was compared with that of corresponding matched control groups. Logistic regression analysis was used to estimate the odds ratios (OR) and 95% confidence intervals (95% CI) for relationship between diabetes and AD risk. The prevalence of diabetes was lower in AD cases than that of control subjects, whether it is the overall AD, type A AD or type B AD group (4.7% vs. 10.0%, 2.9% vs. 8.8%, 5.9% vs. 10.9%, all P<0.001). Furthermore, in multivariate model, diabetes was found to be associated with lower AD risk, which not only applies to the overall AD (OR = 0.2, 95%CI: 0.15-0.26), but also type A AD (OR = 0.12, 95% CI: 0.07-0.20) and type B AD (OR = 0.25, 95%CI: 0.18-0.33). We observed the paradoxical inverse relationship between DM and risk of AD in the Chinese population. These results suggest diabetes may play a protective role in the development of AD. However, further studies are needed to enrich related evidence, especially with regard to underlying mechanisms for these trends.

A scan statistic for identifying optimal risk windows in vaccine safety studies using self-controlled case series design.

PubMed

Xu, Stanley; Hambidge, Simon J; McClure, David L; Daley, Matthew F; Glanz, Jason M

2013-08-30

In the examination of the association between vaccines and rare adverse events after vaccination in postlicensure observational studies, it is challenging to define appropriate risk windows because prelicensure RCTs provide little insight on the timing of specific adverse events. Past vaccine safety studies have often used prespecified risk windows based on prior publications, biological understanding of the vaccine, and expert opinion. Recently, a data-driven approach was developed to identify appropriate risk windows for vaccine safety studies that use the self-controlled case series design. This approach employs both the maximum incidence rate ratio and the linear relation between the estimated incidence rate ratio and the inverse of average person time at risk, given a specified risk window. In this paper, we present a scan statistic that can identify appropriate risk windows in vaccine safety studies using the self-controlled case series design while taking into account the dependence of time intervals within an individual and while adjusting for time-varying covariates such as age and seasonality. This approach uses the maximum likelihood ratio test based on fixed-effects models, which has been used for analyzing data from self-controlled case series design in addition to conditional Poisson models. Copyright © 2013 John Wiley & Sons, Ltd.

Occupation and male lung cancer: a case-control study in northern Sweden.

PubMed Central

Damber, L A; Larsson, L G

1987-01-01

Using a case-control study comprising about 600 men with lung cancer in northern Sweden the potential risk of different occupations and groups of occupations was studied. Longitudinal data concerning occupation, employment, and smoking habits were obtained by questionnaires. Some occupational groups (underground miners, copper smelter workers, electricians, and plumbers) exposed to previously known lung carcinogenic agents such as radon daughters, arsenic, and asbestos, had considerably increased odds ratios, which persisted after adjustment for smoking. A slightly raised odds ratio was observed in a group of blue collar workers potentially exposed to lung carcinogenic agents; this rise in the group as a whole mainly disappeared after adjustment for smoking. Farmers and foresters had strikingly low odds ratios, which could only partly be explained by their more moderate smoking habits. The population aetiological fraction attributable to occupation was estimated as 9%. PMID:3620367

Birth Weight and Acute Childhood Leukemia: A Meta-analysis of Observational Studies

DTIC Science & Technology

2005-03-22

22 MAR 2005 2. REPORT TYPE 3. DATES COVERED - 4. TITLE AND SUBTITLE Birth Weight and Acute Childhood Leukemia: A Meta - analysis of Observational...and to quantify the strength of the relationships. We conducted a meta - analysis of nine case-control studies (published between 1991 and 2004...Based on a meta - analysis of only three case-control studies (published between 1997 and 2004) involving over 700 children with AML and over 1,900

Environmental and occupational risk factors for progressive supranuclear palsy: Case-control study.

PubMed

Litvan, Irene; Lees, Peter S J; Cunningham, Christopher R; Rai, Shesh N; Cambon, Alexander C; Standaert, David G; Marras, Connie; Juncos, Jorge; Riley, David; Reich, Stephen; Hall, Deborah; Kluger, Benzi; Bordelon, Yvette; Shprecher, David R

2016-05-01

The cause of progressive supranuclear palsy (PSP) is largely unknown. Based on evidence for impaired mitochondrial activity in PSP, we hypothesized that the disease may be related to exposure to environmental toxins, some of which are mitochondrial inhibitors. This multicenter case-control study included 284 incident PSP cases of 350 cases and 284 age-, sex-, and race-matched controls primarily from the same geographical areas. All subjects were administered standardized interviews to obtain data on demographics, residential history, and lifetime occupational history. An industrial hygienist and a toxicologist unaware of case status assessed occupational histories to estimate past exposure to metals, pesticides, organic solvents, and other chemicals. Cases and controls were similar on demographic factors. In unadjusted analyses, PSP was associated with lower education, lower income, more smoking pack-years, more years of drinking well water, more years living on a farm, more years living 1 mile from an agricultural region, more transportation jobs, and more jobs with exposure to metals in general. However, in adjusted models, only more years of drinking well water was significantly associated with PSP. There was an inverse association with having a college degree. We did not find evidence for a specific causative chemical exposure; higher number of years of drinking well water is a risk factor for PSP. This result remained significant after adjusting for income, smoking, education and occupational exposures. This is the first case-control study to demonstrate PSP is associated with environmental factors. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

Measuring the physical and economic impact of filarial lymphoedema in Chikwawa district, Malawi: a case-control study.

PubMed

Stanton, Michelle C; Yamauchi, Masato; Mkwanda, Square Z; Ndhlovu, Paul; Matipula, Dorothy Emmie; Mackenzie, Charles; Kelly-Hope, Louise A

2017-04-03

Lymphatic filariasis (LF) is one of the primary causes of lymphoedema in sub-Saharan Africa, and has a significant impact on the quality of life (QoL) of those affected. In this paper we assess the relative impact of lymphoedema on mobility and income in Chikwawa district, Malawi. A random sample of 31 people with lymphoedema and 31 matched controls completed a QoL questionnaire from which both an overall and a mobility-specific score were calculated. Two mobility tests were undertaken, namely the 10 m walking test [10MWT] and timed up and go [TUG] test, and a subset of 10 cases-control pairs wore GPS data loggers for 3 weeks to measure their mobility in a more natural setting. Retrospective economic data was collected from all 31 case-control pairs, and each participant undertaking the GPS activity recorded daily earnings and health expenditure throughout the observation period. Cases had a significantly poorer overall QoL (cases = 32.2, controls = 6.0, P < 0.01) and mobility-specific (cases = 43.1, controls = 7.4, P < 0.01) scores in comparison to controls. Cases were also significantly slower (P < 0.01) at completing the timed mobility tests, e.g. mean 10MWT speed of 0.83 m/s in comparison to 1.10 m/s for controls. An inconsistent relationship was observed between mobility-specific QoL scores and the timed test results for cases (10MWT correlation = -0.06, 95% CI = (-0.41, 0.30)), indicating that their perceived disability differed from their measured disability, whereas the results were consistent for controls (10MWT correlation = -0.61, 95% CI = (-0.79, -0.34)). GPS summaries indicated that cases generally walk shorter distances at slower speeds than control, covering a smaller geographical area (median area by kernel smoothing: cases = 1.25 km 2 , controls = 2.10 km 2 , P = 0.16). Cases reported earning less than half that earned by controls per week (cases = $0.70, controls = $1.86, P�

Individual Correlates of Podoconiosis in Areas of Varying Endemicity: A Case-Control Study

PubMed Central

Molla, Yordanos B.; Le Blond, Jennifer S.; Wardrop, Nicola; Baxter, Peter; Atkinson, Peter M.; Newport, Melanie J.; Davey, Gail

2013-01-01

Background Podoconiosis is a non-filarial form of elephantiasis resulting in lymphedema of the lower legs. Previous studies have suggested that podoconiosis arises from the interplay of individual and environmental factors. Here, our aim was to understand the individual-level correlates of podoconiosis by comparing 460 podoconiosis-affected individuals and 707 unaffected controls. Methods/principal findings This was a case-control study carried out in six kebeles (the lowest governmental administrative unit) in northern Ethiopia. Each kebele was classified into one of three endemicity levels: ‘low’ (prevalence <1%), ‘medium’ (1–5%) and ‘high’ (>5%). A total of 142 (30.7%) households had two or more cases of podoconiosis. Compared to controls, the majority of the cases, especially women, were less educated (OR = 1.7, 95% CI = 1.3 to 2.2), were unmarried (OR = 3.4, 95% CI = 2.6–4.6) and had lower income (t = −4.4, p<0.0001). On average, cases started wearing shoes ten years later than controls. Among cases, age of first wearing shoes was positively correlated with age of onset of podoconiosis (r = 0.6, t = 12.5, p<0.0001). Among all study participants average duration of shoe wearing was less than 30 years. Between both cases and controls, people in ‘high’ and ‘medium’ endemicity kebeles were less likely than people in ‘low’ endemicity areas to ‘ever’ have owned shoes (OR = 0.5, 95% CI = 0.4–0.7). Conclusions Late use of shoes, usually after the onset of podoconiosis, and inequalities in education, income and marriage were found among cases, particularly among females. There were clustering of cases within households, thus interventions against podoconiosis will benefit from household-targeted case tracing. Most importantly, we identified a secular increase in shoe-wearing over recent years, which may give opportunities to promote shoe-wearing without increasing stigma among those at high risk of

Identification and medical utilization of incident cases of alcohol dependence: A population-based case-control study.

PubMed

Pan, Chun-Hung; Li, Min-Shan; Yang, Tien-Wey; Huang, Ming-Chyi; Su, Sheng-Shiang; Hung, Yen-Ni; Chen, Chiao-Chicy; Kuo, Chian-Jue

2018-05-05

Patients with alcohol dependence (AD) often seek help from medical professionals due to alcohol-related diseases, but the overall distribution of medical specialties identifying new AD cases is unclear. We investigated how such cases were identified and how medical resources were utilized before the identification of AD in a nationwide cohort. We enrolled a population-based cohort (N = 1,000,000) using the National Health Insurance Research Database of Taiwan; 8181 cases with incident AD were retrieved between January 1, 2000, and December 31, 2010. For this nested case-control study, four controls were matched for age and sex with each case based on risk-set sampling. We measured various dimensions of medical utilization before AD was diagnosed, including department visited, physical comorbidity, and medication used. Conditional logistic regression was used for estimating the variables associated with AD. Patients living in less urbanized areas who were unemployed were more likely to develop AD. The highest proportions (34.2%) of AD cases were identified in the internal medicine department, followed by the emergency (22.3%) and psychiatry (18.7%) departments. AD patients had a higher risk of comorbid chronic hepatic disease (adjusted RR = 2.72, p < 0.001) before identification of AD than controls. AD patients also had greater numbers of hospital admissions than controls, including non-psychiatric and psychiatric hospitalizations. Outpatient visit numbers were similar for AD patients and controls. The findings indicate that clinicians providing care in diverse medical settings should be prepared to screen for unhealthy alcohol use and to mitigate its detrimental effects. Copyright © 2018 Elsevier B.V. All rights reserved.

Case-control study of multiple chemical sensitivity, comparing haematology, biochemistry, vitamins and serum volatile organic compound measures.

PubMed

Baines, Cornelia Johanna; McKeown-Eyssen, Gail Elizabeth; Riley, Nicole; Cole, David Edward C; Marshall, Lynn; Loescher, Barry; Jazmaji, Vartouhi

2004-09-01

Multiple chemical sensitivity (MCS), although poorly understood, is associated with considerable morbidity. To investigate potential biological mechanisms underlying MCS in a case-control study. Two hundred and twenty-three MCS cases and 194 controls (urban females, aged 30-64 years) fulfilled reproducible eligibility criteria with discriminant validity. Routine laboratory results and serum levels of volatile organic compounds (VOCs) were compared. Dose-response relationships, a criterion for causality, were examined linking exposures to likelihood of case status. Routine laboratory investigations revealed clinically unimportant case-control differences in means. Confounder-adjusted odds ratios (OR) showed MCS was negatively associated with lymphocyte count and total plasma homocysteine, positively associated with mean cell haemoglobin concentration, alanine aminotransferase and serum vitamin B6, and not associated with thyroid stimulating hormone, folate or serum vitamin B12. More cases than controls had detectable serum chloroform (P = 0.001) with the OR for detectability 2.78 (95% confidence interval = 1.73-4.48, P < 0.001). Chloroform levels were higher in cases. However, cases had significantly lower means of detectable serum levels of ethylbenzene, m&p-xylene, 3-methylpentane and hexane, and means of all serum levels of 1,3,5- and 1,2,3-trimethylbenzene, 2- and 3-methylpentane, and m&p-xylene. Our findings are inconsistent with proposals that MCS is associated with vitamin deficiency or thyroid dysfunction, but the association of lower lymphocyte counts with an increased likelihood of MCS is consistent with theories of immune dysfunction in MCS. Whether avoidance of exposures or different metabolic pathways in cases explain the observed lower VOC levels or the higher chloroform levels should be investigated.

Preeclampsia and toxic metals: a case-control study in Kinshasa, DR Congo.

PubMed

Elongi Moyene, Jean-Pierre; Scheers, Hans; Tandu-Umba, Barthélémy; Haufroid, Vincent; Buassa-Bu-Tsumbu, Baudouin; Verdonck, Fons; Spitz, Bernard; Nemery, Benoit

2016-04-05

Preeclampsia is frequent in Kinshasa (Democratic Republic of Congo), especially during the dry season. We tested whether preeclampsia was associated with exposure to environmental metals. Using a case-control design, 88 women hospitalized with preeclampsia (cases) and 88 healthy pregnant women from the antenatal clinic (controls) were included in the study; 67 and 109 women were enrolled during the rainy and dry season, respectively. The concentrations of 24 elements were quantified by inductively coupled plasma mass spectrometry (ICP-MS) in 24-h urine collections. Differences in the urinary excretion of metals were investigated between cases and controls, and the interaction with season was assessed. Cases and controls were well matched regarding age, parity and duration of pregnancy. In controls, the urinary concentrations of most elements were substantially higher than reference values for adults from industrially developed countries, e.g. for lead: geometric mean (GM) 8.0 μg/L [25(th)-75(th) percentile 3.1-13.8]. The daily urinary excretions of 14 metals were significantly higher in women with preeclampsia than in control women, e.g. for lead: GM 61 μg/day (25(th)-75(th) percentile 8-345) in women with preeclampsia vs 9 μg/day (25(th)-75(th) percentile 3-21) in controls (p < 0.001). A significant interaction was found between season and preeclampsia for several elements, with higher urinary excretions in preeclamptic women than controls during the dry season, but not during the rainy season. This study revealed not only that women with preeclampsia excrete higher amounts of several toxic metals, especially lead, than control women, but also that this excretion exhibits seasonal variation, thus possibly explaining the high incidence and seasonal variation of preeclampsia in Kinshasa. Although the exact sources of this exposure are unknown, these findings underscore the need for preventing environmental exposures to lead and other toxic metals.