Case-control studies in diabetes. Do they really use a case-control design?

PubMed

Ramos, Analía; Mendoza, Lilian Cristina; Rabasa, Fernanda; Bolíbar, Ignasi; Puig, Teresa; Corcoy, Rosa

2017-07-01

Studies defined as case-control do not always use this design. We aimed to estimate the frequency of mislabelled case-control studies in published articles in the area of diabetes and to identify the predictors of incorrect labelling. We searched Medline and Web of Science for articles with "diabetes" and "case control" in title and filtered for language (English/Romance) and period (January 2010-December 2014). Inclusion criteria were: (1) statement to use a case-control design in title, (2) to be a final full-length publication and (3) to have original data in the area of diabetes. Three independent reviewers went through titles, looked for full texts and reviewed them. Discrepancies were settled with a fourth reviewer. Expert epidemiologist advice was requested in case of doubt. case-control mislabelling; addressed predictors: publication year, journal impact factor and journal subject. proportion of mislabelled CC articles and assessment of predictors by multivariate logistic regression analysis. We retrieved 362 articles, 251 of them fulfilling inclusion criteria. The proportion of mislabelled CC studies was 43.8% (confidence interval 95% 37.7-50.0%). Most mislabelled studies had a cross-sectional design (82.7%). Predictors of mislabelling were publication year, journal impact factor and journal area. A relevant subset of studies defined as case-control in the area of diabetes correspond to mislabelled cross-sectional studies. Incorrect labelling misleads readers regarding the interpretation of results and the cause-effect hypothesis. Researchers, reviewers and editors should be aware of and commit to settle this issue.

Case-Control Study of Writer's Cramp

ERIC Educational Resources Information Center

Roze, E.; Soumare, A.; Pironneau, I.; Sangla, S.; de Cock, V. Cochen; Teixeira, A.; Astorquiza, A.; Bonnet, C.; Bleton, J. P.; Vidailhet, M.; Elbaz, A.

2009-01-01

Task-specific focal dystonias are thought to be due to a combination of individual vulnerability and environmental factors. There are no case-control studies of risk factors for writer's cramp. We undertook a case-control study of 104 consecutive patients and matched controls to identify risk factors for the condition. We collected detailed data…

Accounting for control mislabeling in case-control biomarker studies.

PubMed

Rantalainen, Mattias; Holmes, Chris C

2011-12-02

In biomarker discovery studies, uncertainty associated with case and control labels is often overlooked. By omitting to take into account label uncertainty, model parameters and the predictive risk can become biased, sometimes severely. The most common situation is when the control set contains an unknown number of undiagnosed, or future, cases. This has a marked impact in situations where the model needs to be well-calibrated, e.g., when the prediction performance of a biomarker panel is evaluated. Failing to account for class label uncertainty may lead to underestimation of classification performance and bias in parameter estimates. This can further impact on meta-analysis for combining evidence from multiple studies. Using a simulation study, we outline how conventional statistical models can be modified to address class label uncertainty leading to well-calibrated prediction performance estimates and reduced bias in meta-analysis. We focus on the problem of mislabeled control subjects in case-control studies, i.e., when some of the control subjects are undiagnosed cases, although the procedures we report are generic. The uncertainty in control status is a particular situation common in biomarker discovery studies in the context of genomic and molecular epidemiology, where control subjects are commonly sampled from the general population with an established expected disease incidence rate.

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

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

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

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

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

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

Urban Background Study Webinar

EPA Pesticide Factsheets

This webinar presented the methodology developed for collecting a city-wide or urban area background data set, general results of southeastern cities data collected to date, and a case study that used this sampling method.

Low control beliefs in relation to school dropout and poor health: findings from the SIODO case-control study.

PubMed

Bosma, Hans; Theunissen, Marie-José; Verdonk, Petra; Feron, Frans

2014-11-28

There is cumulating evidence that health is compromised through adverse socioeconomic conditions negatively affecting how people think, feel, and behave. Low control beliefs might be a key mechanism. The reversed possibility that low control beliefs might set people on a pathway towards adverse socioeconomic and health-related outcomes is much less examined. A case-control design was used, consisting of 330 cases who dropped out of school in the 2010-2011 school year and 330 controls who still attended school at the end of that year. The respondents, aged between 18 and 23, came from Eindhoven and surrounding areas in the south-east of The Netherlands. A questionnaire asked for current health status, recalled socioeconomic and social background, and recalled control beliefs (mastery and general self-efficacy). Logistic regression analyses were used. Recalls of low mastery and low self-efficacy were strongly related to both dropout and less than good health. Low socioeconomic background was also associated to odds of dropout, but did not confound or moderate the associations of low control beliefs with dropout and health. Odds ratios of dropout and less than good health indicated at least twice the odds of a poor outcome with recalls of low control beliefs. Independent of the socioeconomic background, low control beliefs are related to heightened odds of both poor health and school dropout. Individual differences in control beliefs might thus be as fundamental as socioeconomic conditions in generating life-course socioeconomic and health-related pathways. Although the findings should first be cross-validated in prospective studies, public health professionals working with youth might already start considering early interventions in youth with all too fatalistic and powerless mind-sets.

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

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.

Risk prediction for early-onset gastric carcinoma: a case-control study of polygenic gastric cancer in Han Chinese with hereditary background.

PubMed

Yuan, Jiajia; Li, Yanyan; Tian, Tiantian; Li, Na; Zhu, Yan; Zou, Jianling; Gao, Jing; Shen, Lin

2016-06-07

Recent genomewide studies have identified several germline variations associated with gastric cancer. The aim of the present study was to identify, in a Chinese Han population, the individual and combined effects of those single nucleotide polymorphisms (SNPs) that increase the risk of early-onset gastric cancer. We conducted a case-control study comprising 116 patients with gastric cancer as well as 102 sex- and age-matched controls and confirmed that the SNPs MUC1 (mucin 1) rs9841504 and ZBTB20 (zinc finger and BTB domain containing 20) rs4072037 were associated with an increased gastric cancer risk. Of the 116 patients diagnosed with cancer, 65 had at least 1 direct lineal relative with carcinoma of the digestive system or breast/ovarian cancer. These 65 had another 4 SNPs associated with gastric cancer susceptibility: PSCA (prostate stem cell antigen) rs2294008, PLCE1 (phospholipase C epsilon 1) rs2274223, PTGER4/PRKAA1 (prostaglandin E receptor 4/ protein kinase AMP-activated catalytic subunit alpha 1) rs13361707, and TYMS (thymidylate synthetase) rs2790. However, each of these low-penetrance susceptibility polymorphisms alone is not considered influential enough to predict the absolute risk of early-onset gastric cancer. Thus we decided to study different combinations of polygenes as they affected for our population. Those subjects with both the risk alleles MUC1 rs9841504 and ZBTB20 rs4072037 had a greater than 3-fold increased risk of gastric cancer. Also those with a hereditary background including the risk alleles PLCE1 rs2274223 and PTGER4/PRKAA1 rs13361707 were 3 times more susceptible to cardia cancer than those without. These findings show that the study of combined polymorphisms, instead of single low-penetrance variations in susceptibility, may lead to a high-risk classification for a specific population.

Risk prediction for early-onset gastric carcinoma: a case-control study of polygenic gastric cancer in Han Chinese with hereditary background

PubMed Central

Yuan, Jiajia; Li, Yanyan; Tian, Tiantian; Li, Na; Zhu, Yan; Zou, Jianling; Gao, Jing; Shen, Lin

2016-01-01

Recent genomewide studies have identified several germline variations associated with gastric cancer. The aim of the present study was to identify, in a Chinese Han population, the individual and combined effects of those single nucleotide polymorphisms (SNPs) that increase the risk of early-onset gastric cancer. We conducted a case-control study comprising 116 patients with gastric cancer as well as 102 sex- and age-matched controls and confirmed that the SNPs MUC1 (mucin 1) rs9841504 and ZBTB20 (zinc finger and BTB domain containing 20) rs4072037 were associated with an increased gastric cancer risk. Of the 116 patients diagnosed with cancer, 65 had at least 1 direct lineal relative with carcinoma of the digestive system or breast/ovarian cancer. These 65 had another 4 SNPs associated with gastric cancer susceptibility: PSCA (prostate stem cell antigen) rs2294008, PLCE1 (phospholipase C epsilon 1) rs2274223, PTGER4/PRKAA1 (prostaglandin E receptor 4/protein kinase AMP-activated catalytic subunit alpha 1) rs13361707, and TYMS (thymidylate synthetase) rs2790. However, each of these low-penetrance susceptibility polymorphisms alone is not considered influential enough to predict the absolute risk of early-onset gastric cancer. Thus we decided to study different combinations of polygenes as they affected for our population. Those subjects with both the risk alleles MUC1 rs9841504 and ZBTB20 rs4072037 had a greater than 3-fold increased risk of gastric cancer. Also those with a hereditary background including the risk alleles PLCE1 rs2274223 and PTGER4/PRKAA1 rs13361707 were 3 times more susceptible to cardia cancer than those without. These findings show that the study of combined polymorphisms, instead of single low-penetrance variations in susceptibility, may lead to a high-risk classification for a specific population. PMID:27127881

Case Study of K-12 Public School Superintendents Having Business Background and No Teaching Experience

ERIC Educational Resources Information Center

Novak, James

2012-01-01

The purpose of this study was to describe the experiences of superintendents with business backgrounds and who lack teaching experience. There is a shortage of qualified superintendent candidates in K-12 school districts. As a result, some school boards are hiring nontraditional superintendents. This qualitative case study is important because it…

Observational Studies: Cohort and Case-Control Studies

PubMed Central

Song, Jae W.; Chung, Kevin C.

2010-01-01

Observational studies are an important category of study designs. To address some investigative questions in plastic surgery, randomized controlled trials are not always indicated or ethical to conduct. Instead, observational studies may be the next best method to address these types of questions. Well-designed observational studies have been shown to provide results similar to randomized controlled trials, challenging the belief that observational studies are second-rate. Cohort studies and case-control studies are two primary types of observational studies that aid in evaluating associations between diseases and exposures. In this review article, we describe these study designs, methodological issues, and provide examples from the plastic surgery literature. PMID:20697313

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

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

The Upper Midwest Health Study: Industry and Occupation of Glioma Cases and Controls

PubMed Central

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.

2015-01-01

Background 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. Materials and Methods 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. Results 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). Conclusions 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. PMID:22715102

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.

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.

Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise

NASA Technical Reports Server (NTRS)

Eckstein, M. P.; Ahumada, A. J. Jr; Watson, A. B.

1997-01-01

Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background.

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

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

Putative periodontopathic bacteria and herpesviruses in pregnant women: a case-control study.

PubMed

Lu, Haixia; Zhu, Ce; Li, Fei; Xu, Wei; Tao, Danying; Feng, Xiping

2016-06-15

Little is known about herpesvirus and putative periodontopathic bacteria in maternal chronic periodontitis. The present case-control study aimed to explore the potential relationship between putative periodontopathic bacteria and herpesviruses in maternal chronic periodontitis.Saliva samples were collected from 36 pregnant women with chronic periodontitis (cases) and 36 pregnant women with healthy periodontal status (controls). Six putative periodontopathic bacteria (Porphyromonas gingivalis [Pg], Aggregatibacer actinomycetemcomitans [Aa], Fusobacterium nucleatum [Fn], Prevotella intermedia [Pi], Tannerella forsythia [Tf], and Treponema denticola [Td]) and three herpesviruses (Epstein-Barr virus [EBV], human cytomegalovirus [HCMV], and herpes simplex virus [HSV]) were detected. Socio-demographic data and oral health related behaviors, and salivary estradiol and progesterone levels were also collected. The results showed no significant differences in socio-demographic background, oral health related behaviors, and salivary estradiol and progesterone levels between the two groups (all P > 0.05). The detection rates of included periodontopathic microorganisms were not significantly different between the two groups (all P > 0.05), but the coinfection rate of EBV and Pg was significantly higher in the case group than in the control group (P = 0.028). EBV and Pg coinfection may promote the development of chronic periodontitis among pregnant women.

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

Factors associated with obesity: a case-control study of young adult Singaporean males.

PubMed

Shi, Haiyuan; Jiang, Bo; Wei Sim, Joshua Dao; Chum, Zhi Zhen; Ali, Noreffendy Bin; Toh, Mun Heng

2014-10-01

A case-control study among Singapore Armed Forces' newly enlisted Servicemen was conducted to examine factors associated with male obesity. Four hundred and fifty-nine individuals from the Obese Basic Military Training program were selected as "cases" (average age: 19.5, body mass index: 30.4) and another 340 individuals were selected from the Normal Basic Military Training program as "controls" (average age: 19.3, body mass index: 21.4). Information such as family background, socioeconomic factors, and lifestyle practices were captured using facilitator-led questionnaires. Several variables were significantly associated with obesity after adjustments for possible confounders. These include childhood obesity (odds ratio [OR] = 2.06), less than an hour of exercise per day (OR = 2.97), Indian ethnicity (OR = 2.22), specific education backgrounds (especially that of Institute of Technical Education-OR = 2.75), father's employment at nonmanagerial/professional jobs (OR = 1.52), mother's employment at managerial/professional jobs (OR = 2.02), regular smoking (OR = 1.73) and alcohol consumption (OR = 2.26), 6 hours or less of sleep (OR = 3.73), obesity among family members (OR = 1.86 for mother; OR = 2.98 for siblings), parental history of diabetes mellitus (OR = 2.22 for father; OR = 2.70 for mother), and eating at inexpensive local food stalls (OR = 1.82). Our study found that a number of factors, ranging from personal and family backgrounds to lifestyle choices, were significantly associated with obesity among male youths. Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.

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.

A sham case-control study of effectiveness of DTP-Hib-hepatitis B vaccine against rotavirus acute gastroenteritis in Kenya

PubMed Central

2014-01-01

Background In many GAVI-eligible countries, effectiveness of new vaccines will be evaluated by case-control methodology. To inform the design and assess selection bias of a future case-control study of rotavirus vaccine effectiveness (VE) in western Kenya, we performed a sham case-control study evaluating VE of pentavalent vaccine (DTP-Hib-HepB) against rotavirus acute gastroenteritis (AGE). Methods From ongoing rotavirus surveillance, we defined cases as children 12 weeks to 23 months old with EIA-confirmed rotavirus AGE. We enrolled one community-based and two hospital-based control groups. We collected vaccination status from cards at enrollment, or later in homes, and evaluated VE by logistic regression. Results We enrolled 91 cases (64 inpatient, 27 outpatient), 252 non-rotavirus AGE facility-based controls (unmatched), 203 non-AGE facility-based controls (age-matched) and 271 community controls (age-matched). Documented receipt of 3 pentavalent doses was 77% among cases and ranged from 81-86% among controls. One percent of cases and 0-2% of controls had no pentavalent doses. The adjusted odds ratio of three versus zero doses for being a case was 3.27 (95% CI 0.01-1010) for community controls and 0.69 (95% CI 0.06-7.75) for non-rotavirus hospital-based AGE controls, translating to VE of -227% and 31%, respectively, with wide confidence intervals. (No facility-based non-AGE controls were unvaccinated.) Similar results were found for ≥2 pentavalent doses and for severe rotavirus AGE. Conclusions The study showed that it is feasible to carry out a real case control in the study area, but this needs to be done as soon as the vaccine is introduced to capture the real impact. Sham case-control or pilot studies before vaccine introduction can be useful in designing case-control VE studies. PMID:24517198

Biomarkers and Bacterial Pneumonia Risk in Patients with Treated HIV Infection: A Case-Control Study

PubMed Central

Bjerk, Sonja M.; Baker, Jason V.; Emery, Sean; Neuhaus, Jacqueline; Angus, Brian; Gordin, Fred M.; Pett, Sarah L.; Stephan, Christoph; Kunisaki, Ken M.

2013-01-01

Background Despite advances in HIV treatment, bacterial pneumonia continues to cause considerable morbidity and mortality in patients with HIV infection. Studies of biomarker associations with bacterial pneumonia risk in treated HIV-infected patients do not currently exist. Methods We performed a nested, matched, case-control study among participants randomized to continuous combination antiretroviral therapy (cART) in the Strategies for Management of Antiretroviral Therapy trial. Patients who developed bacterial pneumonia (cases) and patients without bacterial pneumonia (controls) were matched 1∶1 on clinical center, smoking status, age, and baseline cART use. Baseline levels of Club Cell Secretory Protein 16 (CC16), Surfactant Protein D (SP-D), C-reactive protein (hsCRP), interleukin-6 (IL-6), and d-dimer were compared between cases and controls. Results Cases (n = 72) and controls (n = 72) were 25.7% female, 51.4% black, 65.3% current smokers, 9.7% diabetic, 36.1% co-infected with Hepatitis B/C, and 75.0% were on cART at baseline. Median (IQR) age was 45 (41, 51) years with CD4+ count of 553 (436, 690) cells/mm3. Baseline CC16 and SP-D were similar between cases and controls, but hsCRP was significantly higher in cases than controls (2.94 µg/mL in cases vs. 1.93 µg/mL in controls; p = 0.02). IL-6 and d-dimer levels were also higher in cases compared to controls, though differences were not statistically significant (p-value 0.06 and 0.10, respectively). Conclusions In patients with cART-treated HIV infection, higher levels of systemic inflammatory markers were associated with increased bacterial pneumonia risk, while two pulmonary-specific inflammatory biomarkers, CC16 and SP-D, were not associated with bacterial pneumonia risk. PMID:23457535

A Case-Control Study Estimating Accident Risk for Alcohol, Medicines and Illegal Drugs

PubMed Central

Kuypers, Kim Paula Colette; Legrand, Sara-Ann; Ramaekers, Johannes Gerardus; Verstraete, Alain Gaston

2012-01-01

Background The aim of the present study was to assess the risk of having a traffic accident after using alcohol, single drugs, or a combination, and to determine the concentrations at which this risk is significantly increased. Methods A population-based case-control study was carried out, collecting whole blood samples of both cases and controls, in which a number of drugs were detected. The risk of having an accident when under the influence of drugs was estimated using logistic regression adjusting for gender, age and time period of accident (cases)/sampling (controls). The main outcome measures were odds ratio (OR) for accident risk associated with single and multiple drug use. In total, 337 cases (negative: 176; positive: 161) and 2726 controls (negative: 2425; positive: 301) were included in the study. Results Main findings were that 1) alcohol in general (all the concentrations together) caused an elevated crash risk; 2) cannabis in general also caused an increase in accident risk; at a cut-off of 2 ng/mL THC the risk of having an accident was four times the risk associated with the lowest THC concentrations; 3) when ranking the adjusted OR from lowest to highest risk, alcohol alone or in combination with other drugs was related to a very elevated crash risk, with the highest risk for stimulants combined with sedatives. Conclusion The study demonstrated a concentration-dependent crash risk for THC positive drivers. Alcohol and alcohol-drug combinations are by far the most prevalent substances in drivers and subsequently pose the largest risk in traffic, both in terms of risk and scope. PMID:22952694

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.

Putative periodontopathic bacteria and herpesviruses in pregnant women: a case-control study

PubMed Central

Lu, Haixia; Zhu, Ce; Li, Fei; Xu, Wei; Tao, Danying; Feng, Xiping

2016-01-01

Little is known about herpesvirus and putative periodontopathic bacteria in maternal chronic periodontitis. The present case-control study aimed to explore the potential relationship between putative periodontopathic bacteria and herpesviruses in maternal chronic periodontitis.Saliva samples were collected from 36 pregnant women with chronic periodontitis (cases) and 36 pregnant women with healthy periodontal status (controls). Six putative periodontopathic bacteria (Porphyromonas gingivalis [Pg], Aggregatibacer actinomycetemcomitans [Aa], Fusobacterium nucleatum [Fn], Prevotella intermedia [Pi], Tannerella forsythia [Tf], and Treponema denticola [Td]) and three herpesviruses (Epstein-Barr virus [EBV], human cytomegalovirus [HCMV], and herpes simplex virus [HSV]) were detected. Socio-demographic data and oral health related behaviors, and salivary estradiol and progesterone levels were also collected. The results showed no significant differences in socio-demographic background, oral health related behaviors, and salivary estradiol and progesterone levels between the two groups (all P > 0.05). The detection rates of included periodontopathic microorganisms were not significantly different between the two groups (all P > 0.05), but the coinfection rate of EBV and Pg was significantly higher in the case group than in the control group (P = 0.028). EBV and Pg coinfection may promote the development of chronic periodontitis among pregnant women. PMID:27301874

Primary aldosteronism and thyroid disorders in atrial fibrillation: A Swedish nationwide case-control study.

PubMed

Mourtzinis, Georgios; Adamsson Eryd, Samuel; Rosengren, Annika; Björck, Lena; Adiels, Martin; Johannsson, Gudmundur; Manhem, Karin

2018-05-01

Background Atrial fibrillation is associated with hyperthyroidism. Patients with primary aldosteronism have an increased prevalence of atrial fibrillation. However, the prevalence of primary aldosteronism in the atrial fibrillation population is unknown. Aim This nationwide case-control study aimed to compare the prevalence of primary aldosteronism and thyroid disorders in patients with atrial fibrillation with that of age- and sex-matched controls. Methods We identified all atrial fibrillation cases in Sweden between 1987 and 2013 ( n = 713,569) by using the Swedish National Patient Register. A control cohort without atrial fibrillation was randomly selected from the Swedish Total Population Register with a case to control ratio of 1:2. This control cohort was matched for age, sex and place of birth ( n = 1,393,953). Results The prevalence of primary aldosteronism in December 2013 was 0.056% in the atrial fibrillation cohort and 0.024% in controls. At the same time, the prevalence of hypothyroidism was 5.9% in the atrial fibrillation cohort and 3.7% in controls. The prevalence of hyperthyroidism was 2.3% in the atrial fibrillation cohort and 0.8% in controls. Conclusion This study shows, for the first time, a doubled prevalence of primary aldosteronism in a large cohort of patients with atrial fibrillation compared with the general population. There is also an increased prevalence of hypo- and hyper-thyroidism in patients with atrial fibrillation compared with the general population.

Emergency department injury surveillance and aetiological research: bridging the gap with the two-stage case-control study design.

PubMed

Hagel, Brent E

2011-04-01

To provide an overview of the two-stage case-control study design and its potential application to ED injury surveillance data and to apply this approach to published ED data on the relation between brain injury and bicycle helmet use. Relevant background is presented on injury aetiology and case-control methodology with extension to the two-stage case-control design in the context of ED injury surveillance. The design is then applied to data from a published case-control study of the relation between brain injury and bicycle helmet use with motor vehicle involvement considered as a potential confounder. Taking into account the additional sampling at the second stage, the adjusted and corrected odds ratio and 95% confidence interval for the brain injury-helmet use relation is presented and compared with the estimate from the entire original dataset. Contexts where the two-stage case-control study design might be most appropriately applied to ED injury surveillance data are suggested. The adjusted odds ratio for the relation between brain injury and bicycle helmet use based on all data (n = 2833) from the original study was 0.34 (95% CI 0.25 to 0.46) compared with an estimate from a two-stage case-control design of 0.35 (95% CI 0.25 to 0.48) using only a fraction of the original subjects (n = 480). Application of the two-stage case-control study design to ED injury surveillance data has the potential to dramatically reduce study time and resource costs with acceptable losses in statistical efficiency.

Serum Progesterone Levels in Pregnant Women with Obstructive Sleep Apnea: A Case Control Study

PubMed Central

Lee, Jennifer; Eklund, Elizabeth E.; Lambert-Messerlian, Geralyn; Palomaki, Glenn E.; Butterfield, Kristen; Curran, Patrizia

2017-01-01

Abstract Background: Pregnancy is a risk factor for sleep disordered breathing, including obstructive sleep apnea (OSA). Progesterone, one of the key hormones in pregnancy, a known respiratory drive stimulant, increases ventilation and may protect against OSA. We aimed to examine the relationship between circulating progesterone and OSA, after accounting for body weight and gestational age. Methods: A case control study was conducted of pregnant women with OSA and those at low risk for the disorder. Cases were identified by ICD-9 code and review of medical record. Controls were identified if they scored zero (never) for snoring, apnea, and gasping on the multivariable apnea prediction index questionnaire immediately following delivery. Subjects with available stored first and/or second trimester residual serum samples were then included in this study and serum analyzed for progesterone. Raw progesterone levels were adjusted for the effects of gestational age and maternal weight. Results: Twenty-seven cases and 64 controls with available serum were identified. Women with OSA had greater maternal weight and higher rates of related comorbidities, compared to controls. Progesterone levels correlated positively with gestational age and negatively with greater weight. Progesterone levels, adjusted for gestational age and maternal weight and expressed as multiples of median (MoM), were significantly lower in OSA cases compared to controls in both the first trimester (MoM = 0.71, confidence interval [95% CI] 0.60–0.83) relative to the MoM in controls of 1.00. In the second trimester levels were also lower in OSA cases (MoM = 0.84, 95% CI 0.73–0.96) compared to the MoM of 1.00 in controls. Conclusions: Progesterone levels, after accounting for weight and gestational age, were lower in women with OSA than controls. Progesterone may play a protective role against OSA. PMID:28103130

Neurocognitive performance in family-based and case-control studies of schizophrenia

PubMed Central

Gur, Ruben C.; Braff, David L.; Calkins, Monica E.; Dobie, Dorcas J.; Freedman, Robert; Green, Michael F.; Greenwood, Tiffany A.; Lazzeroni, Laura C.; Light, Gregory A.; Nuechterlein, Keith H.; Olincy, Ann; Radant, Allen D.; Seidman, Larry J.; Siever, Larry J.; Silverman, Jeremy M.; Sprock, Joyce; Stone, William S.; Sugar, Catherine A.; Swerdlow, Neal R.; Tsuang, Debby W.; Tsuang, Ming T.; Turetsky, Bruce I.; Gur, Raquel E.

2014-01-01

Background Neurocognitive deficits in schizophrenia (SZ) are established and the Consortium on the Genetics of Schizophrenia (COGS) investigated such measures as endophenotypes in family-based (COGS-1) and case-control (COGS-2) studies. By requiring family participation, family-based sampling may result in samples that vary demographically and perform better on neurocognitive measures. Methods The Penn computerized neurocognitive battery (CNB) evaluates accuracy and speed of performance for several domains and was administered across sites in COGS-1 and COGS-2. Most tests were included in both studies. COGS-1 included 328 patients with SZ and 497 healthy comparison subjects (HCS) and COGS-2 included 1195 patients and 1009 HCS. Results Demographically, COGS-1 participants were younger, more educated, with more educated parents and higher estimated IQ compared to COGS-2 participants. After controlling for demographics, the two samples produced very similar performance profiles compared to their respective controls. As expected, performance was better and with smaller effect sizes compared to controls in COGS-1 relative to COGS-2. Better performance was most pronounced for spatial processing while emotion identification had large effect sizes for both accuracy and speed in both samples. Performance was positively correlated with functioning and negatively with negative and positive symptoms in both samples, but correlations were attenuated in COGS-2, especially with positive symptoms. Conclusions Patients ascertained through family-based design have more favorable demographics and better performance on some neurocognitive domains. Thus, studies that use case-control ascertainment may tap into populations with more severe forms of illness that are exposed to less favorable factors compared to those ascertained with family-based designs. PMID:25432636

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.

Case-control study on analgesics and nephropathy (SAN): protocol

PubMed Central

Heinemann, Lothar AJ; Garbe, Edeltraut; Lewis, Michael; van der Woude, Fokko; Graf, Helmut

2005-01-01

Background The association between intake of non-phenacetin-containing analgesics and the occurrence of chronic renal failure is still controversially discussed. A new epidemiologic study was planned and conducted in Germany and Austria. Methods/design The objective of the international, multicenter case-control study was to evaluate the association between end-stage renal disease (ESRD) and use of non-phenacetin-containing analgesics with particular emphasis on combined formulations. A targeted sample of 1000 new (incident) dialysis patients, aged less than 50 years, was planned to recruit between January 1, 2001 and December 31, 2004. The age limit was chosen to avoid contamination of the study population with phenacetin-containing analgesics to the extent possible. Four control subjects per ESRD case, matched by age, sex, and region were selected from the population living in the region the case came from. Lifetime exposure to analgesics and potential renal risk factors were recorded in a single face-to-face interview. A set of aids was introduced to reinforce the memory of study participants. A standardized, pre-tested interview questionnaire (participants), a medical documentation sheet (physicians in dialysis centres), a logbook for all activities (dialysis centres) were used to collect the necessary data. Quality management consisted of the standardized procedures, (re-) training and supervision of interviewers, regular checks of all incoming data for completeness and plausibility. The study is scientifically independent and governed by a international Scientific Advisory Committee that bridged the gap between the sponsoring companies and the investigators. Also other advisory groups assisted the managing committee of the study. All relevant German and Austrian nephrological associations supported the study, and the study design was carefully reviewed and approved by the Kidney Foundation of Germany. Discussion The study is expected to answer the main

Risk factors associated with actinic prurigo: a case control study*

PubMed Central

Cuevas-Gonzalez, Juan Carlos; Vega-Memíje, María Elisa; Borges-Yáñez, Socorro Aída; Rodríguez-Lobato, Erika

2017-01-01

Background Actinic prurigo (AP) is an idiopathic photodermatosis. Although its initial manifestations can appear in 6 to 8-year-old children, cases are diagnosed later, between the second and fourth decades of life, when the injuries are exacerbated. Objective To identify risk factors associated with clinical manifestations of AP such as skin and mucosal lesions. Methods Thirty patients with AP and 60 controls were included in the study, the dependent variable was the presence of skin or labial mucosal lesions, the independent variables were age, sex, solar exposure, living with pets or farm animals, exposure to wood smoke, smoking habit, years smoking, and hours spent per day and per week in contact with people who smoke. Results Of the 30 diagnosed AP patients, 66.7% were female. Patients age ranged from 7 to 71 years and the mean age was 35.77 ± 14.55 years. We found significant differences with the age and cohabitation with farm animals. Those who lived with farm animals presented 14.31 times higher probability of developing AP (95% CI 3-78.06). Study limitations This is a case-control study; therefore, a causal relationship cannot be proven, and these results cannot be generalized to every population. Conclusions The identification of factors related to the development of AP increases our knowledge of its physiopathology. Moreover, identifying antigens that possibly trigger the allergic reaction will have preventive and therapeutic applications in populations at risk of AP. PMID:29364431

Humidifier Disinfectants Are a Cause of Lung Injury among Adults in South Korea: A Community-Based Case-Control Study

PubMed Central

Kwon, Geun-Yong; Gwack, Jin; Park, Young-Joon; Youn, Seung-Ki; Kwon, Jun-Wook; Yang, Byung-Guk; Lee, Moo-Song; Jung, Miran; Lee, Hanyi; Jun, Byung-Yool; Lim, Hyun-Sul

2016-01-01

Backgrounds An outbreak of lung injury among South Korean adults was examined in a hospital-based case-control study, and the suspected cause was exposure to humidifier disinfectant (HD). However, a case-control study with community-dwelling controls was needed to validate the previous study’s findings, and to confirm the exposure-response relationship between HD and lung injury. Methods Each case of lung injury was matched with four community-dwelling controls, according to age (±3 years), sex, residence, and history of childbirth since 2006 (for women). Environmental risk factors, which included type and use of humidifier and HD, were investigated using a structured questionnaire during August 2011. The exposure to HD was calculated for both cases and controls, and the corresponding risks of lung injury were compared. Results Among 28 eligible cases, 16 patients agreed to participate, and 60 matched controls were considered eligible for this study. The cases were more likely to have been exposed to HD (odds ratio: 116.1, 95% confidence interval: 6.5–2,063.7). All cases were exposed to HDs containing polyhexamethyleneguanidine phosphate, and the risk of lung injury increased with the cumulative exposure, duration of exposure, and exposure per day. Conclusions This study revealed a statistically significant exposure-response relationship between HD and lung injury. Therefore, continuous monitoring and stricter evaluation of environmental chemicals’ safety should be conducted. PMID:26990641

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.

A case-control study of airways obstruction among construction workers: Airways Obstruction Among Construction Workers

DOE PAGES

Dement, John; Welch, Laura; Ringen, Knut; ...

2015-06-29

Background: 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. Methods: 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. Results: 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. Amore » measure of all VGDF exposures combined was a strong predictor of COPD risk. Conclusions: 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« less

A case-control study of airways obstruction among construction workers: Airways Obstruction Among Construction Workers

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

Dement, John; Welch, Laura; Ringen, Knut

Background: 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. Methods: 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. Results: 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. Amore » measure of all VGDF exposures combined was a strong predictor of COPD risk. Conclusions: 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« less

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.

Background and principles of throttles-only flight control

NASA Technical Reports Server (NTRS)

Burcham, Frank W., Jr.

1995-01-01

There have been many cases in which the crew of a multi-engine airplane had to use engine thrust for emergency flight control. Such a procedure is very difficult, because the propulsive control forces are small, the engine response is slow, and airplane dynamics such as the phugoid and dutch roll are difficult to damp with thrust. In general, thrust increases are used to climb, thrust decreases to descend, and differential thrust is used to turn. Average speed is not significantly affected by changes in throttle setting. Pitch control is achieved because of pitching moments due to speed changes, from thrust offset, and from the vertical component of thrust. Roll control is achieved by using differential thrust to develop yaw, which, through the normal dihedral effect, causes a roll. Control power in pitch and roll tends to increase as speed decreases. Although speed is not controlled by the throttles, configuration changes are often available (lowering gear, flaps, moving center-of-gravity) to change the speed. The airplane basic stability is also a significant factor. Fuel slosh and gyroscopic moments are small influences on throttles-only control. The background and principles of throttles-only flight control are described.

Effect of Primary Elective Cesarean Delivery on Placenta Accreta: A Case-Control Study

PubMed Central

Shi, Xiao-Ming; Wang, Yan; Zhang, Yan; Wei, Yuan; Chen, Lian; Zhao, Yang-Yu

2018-01-01

Background: Cesarean section (CS) is an independent risk factor for placenta accreta. Some researchers think that the timing of primary cesarean delivery is associated with placenta accreta in subsequent pregnancies. The aim of this study was to investigate the risk of placenta accreta following primary CS without labor, also called primary elective CS, in a pregnancy complicated with placenta previa. Methods: A retrospective, single-center, case-control study was conducted at Peking University Third Hospital. Relevant clinical data of singleton pregnancies between January 2010 and September 2017 were recorded. The case group included women with placenta accreta who had placenta previa and one previous CS. Control group included women with one previous CS that was complicated with placenta previa. Maternal age, body mass index, gestational age, fetal birth weight, gravity, parity, induced abortion, the rate of women received assisted reproductive technology, other uterine surgery, and primary elective CS were analyzed between the two groups. Results: The rate of primary elective CS (90.1% vs. 69.9%, P < 0.001) was higher, and maternal age was younger (32.7 ± 4.7 years vs. 34.6 ± 4.0 years, P < 0.001) in case group, compared with control group. Case group also had higher gravity and induced abortions compared with the control group (both P < 0.05). Primary CS without labor was associated with significantly increased risk of placenta accreta in a subsequent pregnancy complicated with placenta previa (odds ratio: 3.32; 95% confidential interval: 1.68–6.58). Conclusion: Women with a primary elective CS without labor have a higher chance of developing an accreta in a subsequent pregnancy that is complicated with placenta previa. PMID:29521289

Association of Low Levels of Vitamin D with Chronic Stable Angina: A Prospective Case-Control Study

PubMed Central

Raina, Ab Hameed; Allai, Mohammad Sultan; Shah, Zafar Amin; Changal, Khalid Hamid; Raina, Manzoor Ahmad; Bhat, Fayaz Ahmad

2016-01-01

Background: Coronary artery disease (CAD) is a major cause of death and disability in developed countries. Chronic stable angina is the initial manifestation of CAD in approximately 50% of the patients. Recent evidence suggests that vitamin D is crucial for cardiovascular health. The prevalence of vitamin D deficiency in our region is 83%. A low level of vitamin D is associated with chronic stable angina. Aim: This study was aimed at supporting or refuting this hypothesis in our population. Materials and Methods: The study was a prospective case-control study. We studied 100 cases of chronic stable angina and compared them with 100 matched controls. Vitamin D deficiency was defined as <20 ng/mL, vitamin D insufficiency as 20-30 ng/mL and normal vitamin D level as 31-150 ng/mL. Results: The prevalence of vitamin D deficiency among cases and controls was 75% and 10%, respectively. 75% of the cases were vitamin D-deficient (<20 ng/mL); 12% were vitamin D-insufficient (20-30 ng/mL), and 13% had normal vitamin D levels (31-150 ng/mL). None had a toxic level of vitamin D. Among the controls, 10% were vitamin D-deficient, 33% were vitamin D-insufficient, and 57% had normal vitamin D levels. The mean vitamin level among cases and controls was 15.53 ng/mL and 40.95 ng/mL, respectively, with the difference being statistically significant (P ≤ 0.0001). There was no statistically significant relation between the disease severities, i.e., on coronary angiography (CAG) with vitamin D level. Among the cases, we found that an increasing age was inversely related to vitamin D levels (P = 0.027). Conclusion: Our study indicates a correlation between vitamin D deficiency and chronic stable angina. Low levels may be an independent, potentially modifiable cardiovascular risk factor. PMID:27114971

Development and validation of a melanoma risk score based on pooled data from 16 case-control studies

PubMed Central

Davies, John R; Chang, Yu-mei; Bishop, D Timothy; Armstrong, Bruce K; Bataille, Veronique; Bergman, Wilma; Berwick, Marianne; Bracci, Paige M; Elwood, J Mark; Ernstoff, Marc S; Green, Adele; Gruis, Nelleke A; Holly, Elizabeth A; Ingvar, Christian; Kanetsky, Peter A; Karagas, Margaret R; Lee, Tim K; Le Marchand, Loïc; Mackie, Rona M; Olsson, Håkan; Østerlind, Anne; Rebbeck, Timothy R; Reich, Kristian; Sasieni, Peter; Siskind, Victor; Swerdlow, Anthony J; Titus, Linda; Zens, Michael S; Ziegler, Andreas; Gallagher, Richard P.; Barrett, Jennifer H; Newton-Bishop, Julia

2015-01-01

Background We report the development of a cutaneous melanoma risk algorithm based upon 7 factors; hair colour, skin type, family history, freckling, nevus count, number of large nevi and history of sunburn, intended to form the basis of a self-assessment webtool for the general public. Methods Predicted odds of melanoma were estimated by analysing a pooled dataset from 16 case-control studies using logistic random coefficients models. Risk categories were defined based on the distribution of the predicted odds in the controls from these studies. Imputation was used to estimate missing data in the pooled datasets. The 30th, 60th and 90th centiles were used to distribute individuals into four risk groups for their age, sex and geographic location. Cross-validation was used to test the robustness of the thresholds for each group by leaving out each study one by one. Performance of the model was assessed in an independent UK case-control study dataset. Results Cross-validation confirmed the robustness of the threshold estimates. Cases and controls were well discriminated in the independent dataset (area under the curve 0.75, 95% CI 0.73-0.78). 29% of cases were in the highest risk group compared with 7% of controls, and 43% of controls were in the lowest risk group compared with 13% of cases. Conclusion We have identified a composite score representing an estimate of relative risk and successfully validated this score in an independent dataset. Impact This score may be a useful tool to inform members of the public about their melanoma risk. PMID:25713022

Case-Control Study of Breast Cancer in India: Role of PERIOD3 Clock Gene Length Polymorphism and Chronotype

PubMed Central

Wirth, Michael D.; Burch, James B.; Hébert, James R.; Kowtal, Pradnya; Kapoor, Aparna; Steck, Susan E.; Hurley, Thomas G.; Gupta, Prakash C.; Pednekar, Mangesh S.; Youngstedt, Shawn D.; Zhang, Hongmei; Sarin, Rajiv

2014-01-01

Background This study examined a PERIOD3 (PER3) gene variable number tandem repeat polymorphism and chronotype as potential BrCA risk factors among Indian women. Methods This case-control study included sporadic, histologically confirmed BrCA cases (n=255) and controls (n=249) from India with data collection from 2010–2012. Results Women with the 4/5 or 5/5 PER3 genotype had a non-statistically significant 33% increased odds of BrCA. BrCA cases were more likely to have a morning (OR=2.43, 95% CI=1.23–4.81) or evening (OR=2.55, 95% CI=1.19–5.47) chronotype. Conclusions Findings are consistent with the possibility that extremes in chronotype may elicit circadian desynchronization, resulting in adverse health outcomes. PMID:24903750

Is bisphosphonate therapy for benign bone disease associated with impaired dental healing? A case-controlled study

PubMed Central

2011-01-01

Background Bisphosphonates are common first line medications used for the management of benign bone disease. One of the most devastating complications associated with bisphosphonate use is osteonecrosis of the jaws which may be related to duration of exposure and hence cumulative dose, dental interventions, medical co-morbidities or in some circumstances with no identifiable aggravating factor. While jaw osteonecrosis is a devastating outcome which is currently difficult to manage, various forms of delayed dental healing may be a less dramatic and, therefore, poorly-recognised complications of bisphosphonate use for the treatment of osteoporosis. It is hypothesised that long-term (more than 1 year's duration) bisphosphonate use for the treatment of post-menopausal osteoporosis or other benign bone disease is associated with impaired dental healing. Methods/Design A case-control study has been chosen to test the hypothesis as the outcome event rate is likely to be very low. A total of 54 cases will be recruited into the study following review of all dental files from oral and maxillofacial surgeons and special needs dentists in Victoria where potential cases of delayed dental healing will be identified. Potential cases will be presented to an independent case adjudication panel to determine if they are definitive delayed dental healing cases. Two hundred and fifteen controls (1:4 cases:controls), matched for age and visit window period, will be selected from those who have attended local community based referring dental practices. The primary outcome will be the incidence of delayed dental healing that occurs either spontaneously or following dental treatment such as extractions, implant placement, or denture use. Discussion This study is the largest case-controlled study assessing the link between bisphosphonate use and delayed dental healing in Australia. It will provide invaluable data on the potential link between bisphosphonate use and osteonecrosis of the jaws

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

Ground control failures. A pictorial view of case studies

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

Peng, S.S.

2007-07-01

The book shows, in pictorial views, many forms and/or stages of types of failures in mines, for instance, cutter, roof falls, and cribs. In each case, the year of occurrence is stated in the beginning so that the environment or technological background under which it occurred are reflected. The narrative than begins with the mining and geological conditions, followed by a description of the ground control problems and recommended solutions and results, if any. The sections cover failure of pillars, roof falls, longwall, roof bolting, multiple-seam mining, floor heave, longwall, flooding and weathering of coal, old workings, and shortwall andmore » thin-seam plow longwall.« less

Role of Surgical Margin on Local Recurrence in High Risk Extremity Osteosarcoma: A Case-Controlled Study

PubMed Central

Song, Won Seok; Kong, Chang-Bae; Cho, Wan Hyeong; Cho, Sang Hyun; Lee, Jeong Dong; Lee, Soo-Yong

2013-01-01

Background The relationship between surgical margin and local recurrence (LR) in osteosarcoma patients with poor responses to chemotherapy is unclear. Moreover, the incidences of LR according to three different resection planes (bone, soft tissue, and perineurovascular) are not commonly known. Methods We evaluated the incidence of LR in three areas. To assess whether there is a role of surgical margin on LR in patients resistant to preoperative chemotherapy, we designed a case (35 patients with LR) and control (70 patients without LR) study. Controls were matched for age, location, initial tumor volume, and tumor volume change during preoperative chemotherapy. Results LR occurred at the soft tissues in 18 cases (51.4%), at the perineurovascular tissues in 11 cases (31.4%), and at the bones in six cases (17.2%). The proportion of inadequate perineurovascular margin was higher in the case group than in the control group (p = 0.01). Within case-control group (105 patients), a correlation between each margin status and LR at corresponding area was found in the bone (p < 0.001) and perineurovascular area (p = 0.001). Conclusions LR is most common in soft tissues. In patients showing similar unfavorable responses to chemotherapy, the losses of perineurovascular fat plane on preoperative magnetic resonance imaging may be a valuable finding in predicting LR. PMID:24009908

What factors play a role in preventing self-immolation? Results from a case-control study in Iran

PubMed Central

Karim, Hosein; Schwebel, David C.; Bazargan-Hejazi, Shahrzad; Mohammadi, Reza; Choubsaz, Mansour; Heidari Zadie, Zahra; Ahmadi, Alireza

2015-01-01

Abstract: Background: To investigate factors related to prevention of self-immolation in west of Iran. Methods: In a case-control study, 30 consecutive cases of deliberate self-inflicted burns admitted to the regional burn center (Imam Khomeini hospital in Kermanshah province, Iran) were compared with controls selected from the community and matched by sex, age, district-county of residence, and rural vs urban living environment. The following characteristics relevant to preventing self-immolation were collected from all cases and controls: main domestic fuel used in the household, awareness about complications of burn injuries, and use of counseling services. Results: Descriptive analyses revealed that kerosene was the main domestic fuel in the household for 83% of cases. Not surprisingly, the main means of self-immolation in 93% of the patients was kerosene, with other fuels such as petrol and domestic gas used in remaining cases. The majority of cases and controls were aware of the potential complications of burn injuries. Use of counseling services was more common in controls. Conclusions: All three aspects of preventing self-immolation – having kerosene and other fuels in the home, being aware of the complications of burn injuries, and using counseling services were present in both the cases and controls. This suggests a large portion of residents in rural Iran are potential self-immolation victims. Increasing preventive strategies may reduce risk of suicide by self-immolation. PMID:26081518

Case-controlled study on risk factors for the development of constipation in hospitalized patients.

PubMed

Ueki, Tetsuya; Nagai, Keiko; Ooe, Nobuharu; Nakashima, Mihoko N; Nishida, Koyo; Nakamura, Junzo; Nakashima, Mikiro

2011-03-01

Constipation is a common problem in hospitalized patients; however, the relative risks of its development with various factors have not been clarified. To clarify the risk factors associated with constipation, we performed a case-controlled study of 165 hospitalized patients who were not laxative users on admission. They were divided into case (n=35) and control (n=130) groups according to laxative administration during hospitalization. Comparison of the patient backgrounds in the two groups revealed significant differences in the activities of daily living, length of fasting, rest level on admission, cerebrovascular disease, and administration of hypnotics. Multiple logistic regression analysis using these five factors as autonomous variables showed that administration of hypnotics (odds ratio, 2.79; 95% confidence interval, 1.10-7.06; p=0.031) was significantly related to laxative use. Therefore, the administration of hypnotics may be the principal cause of constipation development in hospitalized patients and they should be used with caution.

High Seroprevalence of Leptospira Exposure in Meat Workers in Northern Mexico: A Case-Control Study

PubMed Central

Alvarado-Esquivel, Cosme; Hernandez-Tinoco, Jesus; Sanchez-Anguiano, Luis Francisco; Ramos-Nevarez, Agar; Cerrillo-Soto, Sandra Margarita; Saenz-Soto, Leandro; Martinez-Ramirez, Lucio

2016-01-01

Background The seroepidemiology of Leptospira infection in workers occupationally exposed to raw meat has been poorly studied. This work aimed to determine the association between Leptospira exposure and the occupation of meat worker, and to determine the seroprevalence association with socio-demographic, work, clinical and behavioral characteristics of the meat workers studied. Methods We performed a case-control study in 124 meat workers and 124 age- and gender-matched control subjects in Durango City, Mexico. Sera of cases and controls were analyzed for anti-Leptospira IgG antibodies using a commercially available enzyme immunoassay. Data of meat workers were obtained with the aid of a questionnaire. The association of Leptospira exposure with the characteristics of meat workers was analyzed by bivariate and multivariate analyses. Results Anti-Leptospira IgG antibodies were found in 22 (17.7%) of 124 meat workers and in eight (6.5%) of 124 controls (OR = 3.12; 95% CI: 1.33 - 7.33; P = 0.006). Seroprevalence of Leptospira infection was similar between male butchers (17.6%) and female butchers (18.2%) (P = 1.00). Multivariate analysis of socio-demographic, work and behavioral variables showed that Leptospira exposure was associated with duration in the activity, rural residence, and consumption of snake meat and unwashed raw fruits. Conclusions This is the first case-control study of the association of Leptospira exposure with the occupation of meat worker. Results indicate that meat workers represent a risk group for Leptospira exposure. Risk factors for Leptospira exposure found in this study may help in the design of optimal preventive measures against Leptospira infection. PMID:26858797

Association Between Helicobacter pylori Infection and Risk of Periodontal Diseases in Han Chinese: A Case-Control Study

PubMed Central

Yang, Jing; Zhang, Qiang; Chen, Ming; Wu, Wu-zhou; Wang, Rong; Liu, Chang-jun; Li, Bei; Shi, Xin-li; Du, Han-song; Tan, Hua-bing

2016-01-01

Background This study was performed to test the association between Helicobacter pylori (HP) and periodontal disease (PD). Material/Methods This was a case-control study in a comprehensive hospital, including all patients with newly diagnosed PD between 2012 and 2014 as cases and all patients without PD as controls, thorough periodontal examinations. Those who tested positive for HP were examined by means of polymerase chain reaction. Single and multivariate logistic regression was used to analyze the data using SPSS 19.0 software. Results This case-control study included 212 Han Chinese non-smoking adults. The results indicated that HP-positive status significantly increased the risk of PD (2.63 times higher (odds ratio [OR]=2.63; 95% confidence interval [CI]=1.48–4.67). After adjustment for age, sex, level of education, physical exercise, body mass index, and history of alcohol and diabetes mellitus, this association remained significantly (OR=2.82, 95% CI=1.55–5.13). Conclusions PD might be associated with HP infection in adults and HP infection may be a significant and independent risk factor for PD. PMID:26753766

Effectiveness of 23-valent pneumococcal polysaccharide vaccine and seasonal influenza vaccine for pneumonia among the elderly - Selection of controls in a case-control study.

PubMed

Kondo, Kyoko; Suzuki, Kanzo; Washio, Masakazu; Ohfuji, Satoko; Fukushima, Wakaba; Maeda, Akiko; Hirota, Yoshio

2017-08-24

We conducted a case-control study to elucidate associations between pneumonia in elderly individuals and 23-valent pneumococcal polysaccharide vaccine (PPSV23) and seasonal influenza vaccine (influenza vaccine). Here, we examined selection of controls in our study using an analytic epidemiology approach. The study period was from October 1, 2009 through September 30, 2014. Cases comprised ≥65-year-old patients newly diagnosed with pneumonia. For every case with pneumonia, two patients with other diseases (one respiratory medicine, one non-respiratory medicine) who were sex-, age-, visit date- and visit hospital-matched were selected as controls. Odds ratios (ORs) and 95% confidence intervals (CIs) of vaccination for pneumonia were calculated using conditional logistic regression model. Similar analyses were also conducted based on the clinical department of controls. Analysis was conducted in 234 cases and 438 controls. Effectiveness of pneumococcal vaccination or influenza vaccination against pneumonia was not detected. Proportions of either vaccination in controls were greater among respiratory medicine (pneumococcal vaccine, 38%; influenza vaccine, 55%) than among non-respiratory medicine (23%; 48%). Analysis using controls restricted to respiratory medicine showed marginally significant effectiveness of pneumococcal vaccination (OR, 0.59; 95%CI, 0.34-1.03; P=0.064) and influenza vaccination (0.64; 0.40-1.04; 0.072). However, this effectiveness might have been overestimated by selection bias of controls, as pneumonia cases are not necessarily respiratory medicine patients. In the analysis using controls restricted to non-respiratory medicine, OR of pneumococcal vaccination for pneumonia was close to 1, presumably because the proportion of pneumococcal vaccination was higher in cases than in controls. Because pneumococcal vaccine was not routinely administered during the study period, differences in recommendations of vaccination by physician in different

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.

Using full-cohort data in nested case-control and case-cohort studies by multiple imputation.

PubMed

Keogh, Ruth H; White, Ian R

2013-10-15

In many large prospective cohorts, expensive exposure measurements cannot be obtained for all individuals. Exposure-disease association studies are therefore often based on nested case-control or case-cohort studies in which complete information is obtained only for sampled individuals. However, in the full cohort, there may be a large amount of information on cheaply available covariates and possibly a surrogate of the main exposure(s), which typically goes unused. We view the nested case-control or case-cohort study plus the remainder of the cohort as a full-cohort study with missing data. Hence, we propose using multiple imputation (MI) to utilise information in the full cohort when data from the sub-studies are analysed. We use the fully observed data to fit the imputation models. We consider using approximate imputation models and also using rejection sampling to draw imputed values from the true distribution of the missing values given the observed data. Simulation studies show that using MI to utilise full-cohort information in the analysis of nested case-control and case-cohort studies can result in important gains in efficiency, particularly when a surrogate of the main exposure is available in the full cohort. In simulations, this method outperforms counter-matching in nested case-control studies and a weighted analysis for case-cohort studies, both of which use some full-cohort information. Approximate imputation models perform well except when there are interactions or non-linear terms in the outcome model, where imputation using rejection sampling works well. Copyright © 2013 John Wiley & Sons, Ltd.

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.

Lack of Association Between Toxoplasma gondii Infection and Diabetes Mellitus: A Matched Case-Control Study in a Mexican Population

PubMed Central

Alvarado-Esquivel, Cosme; Loera-Moncivais, Nayely; Hernandez-Tinoco, Jesus; Sanchez-Anguiano, Luis Francisco; Hernandez-Madrid, Guillermina; Rabago-Sanchez, Elizabeth; Centeno-Tinoco, Maria Magdalena; Sandoval-Carrillo, Ada A.; Salas-Pacheco, Jose M.; Campos-Moreno, Oscar Vladimir; Antuna-Salcido, Elizabeth Irasema

2017-01-01

Background Very little is known about the association between infection with Toxoplasma gondii (T. gondii) and diabetes mellitus. We perform an age- and gender-matched case-control study to determine the association of T. gondii infection and diabetes mellitus. Methods Cases included 156 patients with diabetes mellitus and 156 controls without diabetes mellitus who attended in two public clinics in Durango City, Mexico. Sera of cases and controls were tested for the presence of anti-Toxoplasma IgG and IgM antibodies using commercially available enzyme-linked fluorescence assays (ELFA). Results Anti-T. gondii IgG antibodies were found in 10 (6.4%) of the 156 cases and in five (3.2%) of the 156 controls (odds ratio (OR): 2.06; 95% confidence interval (CI): 0.69 - 6.19; P = 0.18). The frequency of high (> 150 IU/mL) anti-T. gondii IgG levels in seropositive cases (1/10: 10.0%) was comparable to the one (1/5: 20%) in seropositive controls (OR: 0.44; 95% CI: 0.02 - 9.03; P = 1.00). None of the 10 cases and five controls with seropositivity to anti-T. gondii IgG antibodies were positive for anti-T. gondii IgM antibodies. Stratification by gender showed similar frequencies of T. gondii infection in female cases (7/107: 6.5%) and female controls (4/107: 3.7%) (OR: 1.80; 95% CI: 0.51 - 6.34; P = 0.53), and in male cases (3/49: 6.1%) and male controls (1/49: 2.0%) (OR: 3.13; 95% CI: 0.31 - 31.19; P = 0.61). Conclusions We conclude that there is not serological evidence of an association between T. gondii infection and diabetes mellitus in the studied subjects in Durango City, Mexico. Further studies to elucidate the role of T. gondii in diabetes should be conducted. PMID:28496551

Restaurant outbreak of Legionnaires' disease associated with a decorative fountain: an environmental and case-control study

PubMed Central

O'Loughlin, Rosalyn E; Kightlinger, Lon; Werpy, Matthew C; Brown, Ellen; Stevens, Valerie; Hepper, Clark; Keane, Tim; Benson, Robert F; Fields, Barry S; Moore, Matthew R

2007-01-01

Background From June to November 2005, 18 cases of community-acquired Legionnaires' disease (LD) were reported in Rapid City South Dakota. We conducted epidemiologic and environmental investigations to identify the source of the outbreak. Methods We conducted a case-control study that included the first 13 cases and 52 controls randomly selected from emergency department records and matched on underlying illness. We collected information about activities of case-patients and controls during the 14 days before symptom onset. Environmental samples (n = 291) were cultured for Legionella. Clinical and environmental isolates were compared using monoclonal antibody subtyping and sequence based typing (SBT). Results Case-patients were significantly more likely than controls to have passed through several city areas that contained or were adjacent to areas with cooling towers positive for Legionella. Six of 11 case-patients (matched odds ratio (mOR) 32.7, 95% CI 4.7-∞) reported eating in Restaurant A versus 0 controls. Legionella pneumophila serogroup 1 was isolated from four clinical specimens: 3 were Benidorm type strains and 1 was a Denver type strain. Legionella were identified from several environmental sites including 24 (56%) of 43 cooling towers tested, but only one site, a small decorative fountain in Restaurant A, contained Benidorm, the outbreak strain. Clinical and environmental Benidorm isolates had identical SBT patterns. Conclusion This is the first time that small fountain without obvious aerosol-generating capability has been implicated as the source of a LD outbreak. Removal of the fountain halted transmission. PMID:17688692

Ethnic Variations in Severe Maternal Morbidity in the UK– A Case Control Study

PubMed Central

Nair, Manisha; Kurinczuk, Jennifer J.; Knight, Marian

2014-01-01

Background Previous studies showed a higher risk of maternal morbidity amongst black and other minority ethnic (BME) groups, but were unable to investigate whether this excess risk was concentrated within specific BME groups in the UK. Our aim was to analyse the specific risks and to investigate reasons for any disparity. Methods Unmatched case-control analysis using data from the United Kingdom Obstetric Surveillance System (UKOSS), February 2005-January 2013. Cases were 1,753 women who experienced severe morbidity during the peripartum period. Controls were 3,310 women who delivered immediately before the cases in the same hospital. Multivariable logistic regression modelling was used to adjust for known confounders and to understand their effects. Results Compared with white European women, the odds of severe maternal morbidity were 83% higher among black African women (adjusted odds ratio (aOR) = 1.83; 95% Confidence Interval (CI) = 1.39–2.40), 80% higher among black Caribbean (aOR = 1.80; 95% CI = 1.14–2.82), 74% higher in Bangladeshi (aOR = 1.74; 95% CI = 1.05–2.88), 56% higher in other non-whites (non-Asian) (aOR = 1.56; 95% CI = 1.05–2.33) and 43% higher among Pakistani women (aOR = 1.43; 95% CI = 1.07–1.92). There was no evidence of substantial confounding. Anaemia in current pregnancy, previous pregnancy problems, inadequate utilisation of antenatal care, pre-existing medical conditions, parity>3, and being younger and older were independent risk factors but, the odds of severe maternal morbidity did not differ by socioeconomic status, between smokers and non-smokers or by BMI. Discussion This national study demonstrates an increased risk of severe maternal morbidity among women of ethnic minority backgrounds which could not be explained by known risk factors for severe maternal morbidity. PMID:24743879

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

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.

Formal concept analysis with background knowledge: a case study in paleobiological taxonomy of belemnites

NASA Astrophysics Data System (ADS)

Belohlavek, Radim; Kostak, Martin; Osicka, Petr

2013-05-01

We present a case study in identification of taxa in paleobiological data. Our approach utilizes formal concept analysis and is based on conceiving a taxon as a group of individuals sharing a collection of attributes. In addition to the incidence relation between individuals and their attributes, the method uses expert background knowledge regarding importance of attributes which helps to filter out correctly formed but paleobiologically irrelevant taxa. We present results of experiments carried out with belemnites-a group of extinct cephalopods which seems particularly suitable for such a purpose. We demonstrate that the methods are capable of revealing taxa and relationships among them that are relevant from a paleobiological point of view.

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

Malnutrition and Childhood Disability in Turkana, Kenya: Results from a Case-Control Study

PubMed Central

Evans, Jennifer; Munyendo, David; Zuurmond, Maria; Frison, Severine; Mwenda, Victoria; Otieno, David; Kisia, James

2015-01-01

Background Children with disabilities may be particularly vulnerable to malnutrition, as a result of exclusions and feeding difficulties. However, there is limited evidence currently available on this subject. Methods A population-based case-control study was conducted in Turkana County, Kenya, between July and August 2013. Key informants in the community identified children aged 6 months to 10 years who they believed may have a disability. These children were screened by a questionnaire (UNICEF-Washington Group) and assessed by a paediatrician to confirm whether they had a disability and the type. Two controls without disabilities were selected per case: A sibling control (sibling nearest in age) and a neighbourhood control (nearest neighbour within one year of age). The caregiver completed a questionnaire on behalf of the child (e.g. information on feeding, poverty, illness, education), and anthropometric measures were taken. We undertook multivariable logistic and linear regression analyses to estimate the relationship between disability and malnutrition. Results The study included 311 cases with disabilities, 196 sibling controls and 300 neighbour controls. Children with disabilities were more likely to report a range of feeding difficulties. They were 1.6–2.9 times more likely to have malnutrition in comparison to neighbour controls or family controls, including general malnutrition (low weight for age), stunting (low height for age), low body mass index (BMI) or low mid upper arm circumference (MUAC) for age. Children with disabilities were almost twice as likely to have wasting (low weight for height) in comparison to neighbour controls (OR = 1.9, 95% CI 1.1–3.2), but this difference was not apparent compared with siblings (OR = 1.5, 95% CI 0.8–2.7). Children with disabilities also faced other exclusions. For instance those aged 5+ were much more likely not to attend school than neighbour controls (OR = 8.5, 95% CI 4.3–16.9). Conclusions Children

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

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 operated carpal tunnel syndrome: a multicenter population-based case-control study

PubMed Central

Mattioli, Stefano; Baldasseroni, Alberto; Bovenzi, Massimo; Curti, Stefania; Cooke, Robin MT; Campo, Giuseppe; Barbieri, Pietro G; Ghersi, Rinaldo; Broccoli, Marco; Cancellieri, Maria Pia; Colao, Anna Maria; dell'Omo, Marco; Fateh-Moghadam, Pirous; Franceschini, Flavia; Fucksia, Serenella; Galli, Paolo; Gobba, Fabriziomaria; Lucchini, Roberto; Mandes, Anna; Marras, Teresa; Sgarrella, Carla; Borghesi, Stefano; Fierro, Mauro; Zanardi, Francesca; Mancini, Gianpiero; Violante, Francesco S

2009-01-01

Background Carpal tunnel syndrome (CTS) is a socially and economically relevant disease caused by compression or entrapment of the median nerve within the carpal tunnel. This population-based case-control study aims to investigate occupational/non-occupational risk factors for surgically treated CTS. Methods Cases (n = 220) aged 18-65 years were randomly drawn from 13 administrative databases of citizens who were surgically treated with carpal tunnel release during 2001. Controls (n = 356) were randomly sampled from National Health Service registry records and were frequency matched by age-gender-specific CTS hospitalization rates. Results At multivariate analysis, risk factors were blue-collar/housewife status, BMI ≥ 30 kg/m2, sibling history of CTS and coexistence of trigger finger. Being relatively tall (cut-offs based on tertiles: women ≥165 cm; men ≥175 cm) was associated with lower risk. Blue-collar work was a moderate/strong risk factor in both sexes. Raised risks were apparent for combinations of biomechanical risk factors that included frequent repetitivity and sustained force. Conclusion This study strongly underlines the relevance of biomechanical exposures in both non-industrial and industrial work as risk factors for surgically treated CTS. PMID:19758429

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.

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.

Toxoplasma gondii Infection and Headache: A Matched Case-Control Study in a Public Hospital in Durango City, Mexico

PubMed Central

Alvarado-Esquivel, Cosme; Rico-Almochantaf, Yazmin del Rosario; Sanchez-Anguiano, Luis Francisco; Quinones-Canales, Gerardo; Hernandez-Tinoco, Jesus; Torres-Gonzalez, Jorge; Gonzalez-Silva, Maria Felix; Ramirez-Valles, Eda Guadalupe

2018-01-01

Background Toxoplasma gondii (T. gondii) can disseminate to brain in infected hosts. Little is known about the magnitude of the association between this infection and headache. Therefore, we sought to determine the association of T. gondii seropositivity and headache in patients attending neurological consultations in a public hospital in Durango City, Mexico. Methods Through an age- and gender-matched case-control study, 105 patients suffering from headache and 105 subjects without headache were examined for anti-T. gondii IgG and IgM antibodies using commercially available enzyme-linked immunoassays. Seropositive cases were analyzed for detection of T. gondii DNA by polymerase chain reaction. Results Anti-T. gondii IgG antibodies were found in five (4.8%) of the 105 cases and in seven (6.7%) of the 105 controls (odds ratio (OR) = 0.70; 95% confidence interval (CI): 0.21 - 2.28; P = 0.76). The frequency of high (> 150 IU/mL) levels of anti-T. gondii IgG antibodies among anti-T. gondii IgG positive individuals was significantly (P = 0.01) higher in cases (5/5) than in controls (1/7). Anti-T. gondii IgM antibodies were found in one (20.0%) of the five IgG seropositive cases, and in three (42.9%) of the seven IgG seropositive controls (P = 0.60). T. gondii DNA was not detected in any of the five anti-T. gondii IgG positive cases. No association between T. gondii infection and specific headache types was found. Conclusions This is the first matched case-control study on the association between T. gondii infection and headache. Results suggest that high anti-T. gondii IgG antibody levels, but not T. gondii seropositivity, were associated with headache in the population studied. PMID:29238431

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.

Subfertility and Risk of Testicular Cancer in the EPSAM Case-Control Study

PubMed Central

Zugna, Daniela; Fiano, Valentina; Robles Rodriguez, Nena; Maule, Milena; Gillio-Tos, Anna; Ciuffreda, Libero; Lista, Patrizia; Segnan, Nereo; Merletti, Franco; Richiardi, Lorenzo

2016-01-01

Background/objectives It has been suggested that subfertility and testicular cancer share genetic and environmental risk factors. We studied both subfertility and the strongest known testicular cancer susceptibility gene, the c-KIT ligand (KITLG), whose pathway is involved in spermatogenesis. Methods The EPSAM case-control study is comprised of testicular cancer patients from the Province of Turin, Italy, diagnosed between 1997 and 2008. The present analysis included 245 cases and 436 controls from EPSAM, who were aged 20 years or older at diagnosis/recruitment. The EPSAM questionnaire collected information on factors such as number of children, age at first attempt to conceive, duration of attempt to conceive, use of assisted reproduction techniques, physician-assigned diagnosis of infertility, number of siblings, and self-reported cryptorchidism. Genotyping of the KITLG single nucleotide polymorphism (SNP) rs995030 was performed on the saliva samples of 202 cases and 329 controls. Results Testicular cancer was associated with the number of children fathered 5 years before diagnosis (odds ratio (OR) per additional child: 0.78, 95% confidence interval (CI): 0.58–1.04) and sibship size (OR per additional sibling: 0.76, 95% CI: 0.66–0.88). When considering the reproductive history until 1 year before diagnosis, attempting to conceive for at least 12 months or fathering a child using assisted reproduction techniques was not associated with the risk of testicular cancer, nor was age at first attempt to conceive or physician-assigned diagnosis of infertility. The SNP rs995030 was strongly associated with risk of testicular cancer (per allele OR: 1.83; 95%CI: 1.26–2.64), but it did not modify the association between number of children and the risk of testicular cancer. Conclusion This study supports the repeatedly reported inverse association between number of children and risk of testicular cancer, but it does not find evidence of an association for other

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.

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.

Homocysteine and Coronary Heart Disease: Meta-analysis of MTHFR Case-Control Studies, Avoiding Publication Bias

PubMed Central

Verhoef, Petra; Dötsch-Klerk, Mariska; Lathrop, Mark; Xu, Peng; Nordestgaard, Børge G.; Holm, Hilma; Hopewell, Jemma C.; Saleheen, Danish; Tanaka, Toshihiro; Anand, Sonia S.; Chambers, John C.; Kleber, Marcus E.; Ouwehand, Willem H.; Yamada, Yoshiji; Elbers, Clara; Peters, Bas; Stewart, Alexandre F. R.; Reilly, Muredach M.; Thorand, Barbara; Yusuf, Salim; Engert, James C.; Assimes, Themistocles L.; Kooner, Jaspal; Danesh, John; Watkins, Hugh; Samani, Nilesh J.

2012-01-01

Background Moderately elevated blood levels of homocysteine are weakly correlated with coronary heart disease (CHD) risk, but causality remains uncertain. When folate levels are low, the TT genotype of the common C677T polymorphism (rs1801133) of the methylene tetrahydrofolate reductase gene (MTHFR) appreciably increases homocysteine levels, so “Mendelian randomization” studies using this variant as an instrumental variable could help test causality. Methods and Findings Nineteen unpublished datasets were obtained (total 48,175 CHD cases and 67,961 controls) in which multiple genetic variants had been measured, including MTHFR C677T. These datasets did not include measurements of blood homocysteine, but homocysteine levels would be expected to be about 20% higher with TT than with CC genotype in the populations studied. In meta-analyses of these unpublished datasets, the case-control CHD odds ratio (OR) and 95% CI comparing TT versus CC homozygotes was 1.02 (0.98–1.07; p = 0.28) overall, and 1.01 (0.95–1.07) in unsupplemented low-folate populations. By contrast, in a slightly updated meta-analysis of the 86 published studies (28,617 CHD cases and 41,857 controls), the OR was 1.15 (1.09–1.21), significantly discrepant (p = 0.001) with the OR in the unpublished datasets. Within the meta-analysis of published studies, the OR was 1.12 (1.04–1.21) in the 14 larger studies (those with variance of log OR<0.05; total 13,119 cases) and 1.18 (1.09–1.28) in the 72 smaller ones (total 15,498 cases). Conclusions The CI for the overall result from large unpublished datasets shows lifelong moderate homocysteine elevation has little or no effect on CHD. The discrepant overall result from previously published studies reflects publication bias or methodological problems. Please see later in the article for the Editors' Summary PMID:22363213

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.

A Case-Controlled Study of Altered Visual Art Production in Alzheimer’s and FTLD

PubMed Central

Rankin, Katherine P.; Liu, Anli A.; Howard, Sara; Slama, Hilary; Hou, Craig. E.; Shuster, Karen; Miller, Bruce L.

2009-01-01

Objective To characterize dementia-induced changes in visual art production. Background While case studies show altered visual artistic production in some patients with neurodegenerative disease, no case-controlled studies have quantified this phenomenon across groups of patients. Method Forty-nine subjects [18 Alzheimer’s disease (AD), 9 Frontotemporal Dementia (FTD), 9 Semantic Dementia (SD), 15 healthy older controls (NC)] underwent formal neuropsychological testing of visuospatial, perceptual, and creative functioning, and produced four drawings. Subjective elements of drawings were rated by an expert panel that was blind to diagnosis. Results Despite equal performance on standard visuospatial tests, dementia groups produced distinct patterns of artistic features that were significantly different from NCs. FTDs used more disordered composition and less active mark-making (p<0.05). Both FTDs and SDs drawings were rated as more bizarre and demonstrated more facial distortion than NCs (p<0.05). Also, SDs drastically failed a standardized test of divergent creativity. ADs artwork was more similar to controls than to FTDs or SDs, but showed a more muted color palette (p<0.05) and trends toward including fewer details, less ordered compositions, and occasional facial distortion. Conclusions These group differences in artistic style likely resulted from disease-specific focal neurodegeneration, and elucidate the contributions of particular brain regions to the production of visual art. PMID:17356345

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.

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.

Childhood leukaemia and distance from power lines in California: a population-based case-control study

PubMed Central

Crespi, Catherine M; Vergara, Ximena P; Hooper, Chris; Oksuzyan, Sona; Wu, Sheng; Cockburn, Myles; Kheifets, Leeka

2016-01-01

Background: Studies have reported an increased risk of childhood leukaemia associated with living near high-voltage electric power transmission lines that extend to distances at which magnetic fields from lines are negligible. We conducted a large records-based case-control study of childhood leukaemia risk in the population living near power lines in California. Methods: The study included 5788 childhood leukaemia and 3308 central nervous system (CNS) cancer cases (for comparison) born in and diagnosed in California (1986–2008), and matched to population-based controls by age and sex. We geocoded birth address and estimated the distance from residence to transmission lines using geographic information systems, aerial imagery, and, for some residences, site visits. Results: For leukaemia, there was a slight excess of cases within 50 m of a transmission line over 200 kV (odds ratio 1.4, 95% confidence interval 0.7–2.7). There was no evidence of increased risk for distances beyond 50 m, for lower-voltage lines, or for CNS cancers. Conclusions: Our findings did not clearly support an increased childhood leukaemia risk associated with close proximity (<50 m) to higher voltage lines, but could be consistent with a small increased risk. Reports of increased risk for distances beyond 50 m were not replicated. PMID:27219016

Paternal psychosocial work conditions and mental health outcomes: A case-control study

PubMed Central

Maggi, Stefania; Ostry, Aleck; Tansey, James; Dunn, James; Hershler, Ruth; Chen, Lisa; Hertzman, Clyde

2008-01-01

Background The role of social and family environments in the development of mental health problems among children and youth has been widely investigated. However, the degree to which parental working conditions may impact on developmental psychopathology has not been thoroughly studied. Methods We conducted a case-control study of several mental health outcomes of 19,833 children of sawmill workers and their association with parental work stress, parental socio-demographic characteristics, and paternal mental health. Results Multivariate analysis conducted with four distinct age groups (children, adolescents, young adults, and adults) revealed that anxiety based and depressive disorders were associated with paternal work stress in all age groups and that work stress was more strongly associated with alcohol and drug related disorders in adulthood than it was in adolescence and young adulthood. Conclusion This study provides support to the tenet that being exposed to paternal work stress during childhood can have long lasting effects on the mental health of individuals. PMID:18377651

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

Incidence and risk factors of aplastic anemia in Latin American countries: the LATIN case-control study

PubMed Central

Maluf, Eliane; Hamerschlak, Nelson; Cavalcanti, Alexandre Biasi; Júnior, Álvaro Avezum; Eluf-Neto, José; Falcão, Roberto Passetto; Lorand-Metze, Irene G.; Goldenberg, Daniel; Santana, Cézar Leite; de Oliveira Werneck Rodrigues, Daniela; da Motta Passos, Leny Nascimento; Rosenfeld, Luis Gastão Mange; Pitta, Marimilia; Loggetto, Sandra; Feitosa Ribeiro, Andreza A.; Velloso, Elvira Deolinda; Kondo, Andrea Tiemi; de Miranda Coelho, Erika Oliveira; Pintão, Maria Carolina Tostes; de Souza, Hélio Moraes; Borbolla, José Rafael; Pasquini, Ricardo

2009-01-01

Background Associations between aplastic anemia and numerous drugs, pesticides and chemicals have been reported. However, at least 50% of the etiology of aplastic anemia remains unexplained. Design and Methods This was a case-control, multicenter, multinational study, designed to identify risk factors for agranulocytosis and aplastic anemia. The cases were patients with diagnosis of aplastic anemia confirmed through biopsy or bone marrow aspiration, selected through an active search of clinical laboratories, hematology clinics and medical records. The controls did not have either aplastic anemia or chronic diseases. A total of 224 patients with aplastic anemia were included in the study, each case was paired with four controls, according to sex, age group, and hospital where the case was first seen. Information was collected on demographic data, medical history, laboratory tests, medications, and other potential risk factors prior to diagnosis. Results The incidence of aplastic anemia was 1.6 cases per million per year. Higher rates of benzene exposure (≥30 exposures per year) were associated with a greater risk of aplastic anemia (odds ratio, OR: 4.2; 95% confidence interval, CI: 1.82–9.82). Individuals exposed to chloramphenicol in the previous year had an adjusted OR for aplastic anemia of 8.7 (CI: 0.87–87.93) and those exposed to azithromycin had an adjusted OR of 11.02 (CI 1.14–108.02). Conclusions The incidence of aplastic anemia in Latin America countries is low. Although the research study centers had a high coverage of health services, the underreporting of cases of aplastic anemia in selected regions can be discussed. Frequent exposure to benzene-based products increases the risk for aplastic anemia. Few associations with specific drugs were found, and it is likely that some of these were due to chance alone. PMID:19734415

Evaluating psychiatric case-control studies using the STROBE (STrengthening the Reporting of OBservational Studies in Epidemiology) statement.

PubMed

Goi, Pedro Domingues; Goi, Julia Domingues; Cordini, Kariny Larissa; Ceresér, Keila Mendes; Rocha, Neusa Sica da

2014-01-01

Case-control studies are important in developing clinical and public health knowledge. The STROBE statement (STrengthening the Reporting of OBservational Studies in Epidemiology) was developed to establish a checklist of items that should be included in articles reporting observational studies. Our aim was to analyze whether the psychiatric case-control articles published in Brazilian journals with CAPES Qualis rating B1/B2 in 2009 conformed with the STROBE statement. Descriptive study on psychiatric papers published in Brazilian journals, within the Postgraduate Medical Program on Psychiatry, at Universidade Federal do Rio Grande do Sul. All psychiatric case-control studies from Brazilian Qualis B1/B2 journals of psychiatry, neurology and public health in 2009 were analyzed. The four most specific items of the STROBE statement were used to evaluate whether these studies fitted within the case-control parameters: 1) selection of cases and controls; 2) controlling for bias; 3) statistical analysis; and 4) presentation of results. Sixteen case-control studies were identified, of which eleven (68.75%) were in psychiatry-focused journals. From analysis using the STROBE statement, all of the articles conformed with item 1; two (12.5%) completely conformed with item 2; none completely conformed with item 3; and only three (18.8%) conformed with item 4. The case-control studies analyzed here did not completely conform with the four STROBE statement items for case-control design. In view of the inadequate methodology of the published studies, these findings justify focusing on research and methodology and expanding the investigations on adherence of studies to their designs.

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.

Association Between Zolpidem Use and Glaucoma Risk: A Taiwanese Population-Based Case-Control Study

PubMed Central

Ho, Yi-Hao; Chang, Yue-Cune; Huang, Wei-Cheng; Chen, Hsin-Yi; Lin, Che-Chen; Sung, Fung-Chang

2015-01-01

Background To date, the relationship between zolpidem use and subsequent risk of glaucoma in a Taiwanese population has not been assessed. Methods We used data from the National Health Insurance system to investigate whether zolpidem use was related to glaucoma risk. A 1:4 matched case-control study was conducted. The cases were patients newly diagnosed with glaucoma from 2001 to 2010. The controls were randomly selected non-glaucoma subjects matched by sex and age (±5 years). Zolpidem exposure and/or the average dosage of zolpidem used (mg/year) were evaluated. Medical comorbidities were considered as confounding factors. Multiple logistic regression models were used to evaluate the potential risk of zolpidem exposure on glaucoma with/without adjustment for the effects of confounding variables. Results The exposure rate of zolpidem use in the glaucoma group was significantly higher than that of the control group (2.8% vs. 2.0%, P < 0.0001). The adjusted odds ratio (OR) of the risk of glaucoma for those with zolpidem use vs. those without was 1.19 (95% confidence interval [CI], 1.02–1.38). Compared to non-zolpidem users, zolpidem users with an average dose of more than 200 mg/year had significantly increased risk of glaucoma (OR 1.31, 95% CI 1.03–1.68). Conclusions This study suggests that the use of zolpidem might increase the risk of subsequent glaucoma. Further confirmatory studies are recommended to clarify this important issue. PMID:25720944

Association Between Zolpidem Use and Glaucoma Risk: A Taiwanese Population-Based Case-Control Study.

PubMed

Ho, Yi-Hao; Chang, Yue-Cune; Huang, Wei-Cheng; Chen, Hsin-Yi; Lin, Che-Chen; Sung, Fung-Chang

2014-08-23

Background: To date, the relationship between zolpidem use and subsequent risk of glaucoma in a Taiwanese population has not been assessed.Methods: We used data from the National Health Insurance system to investigate whether zolpidem use was related to glaucoma risk. A 1:4 matched case-control study was conducted. The cases were patients newly diagnosed with glaucoma from 2001 to 2010. The controls were randomly selected non-glaucoma subjects matched by sex and age (±5 years). Zolpidem exposure and/or the average dosage of zolpidem used (mg/year) were evaluated. Medical comorbidities were considered as confounding factors. Multiple logistic regression models were used to evaluate the potential risk of zolpidem exposure on glaucoma with/without adjustment for the effects of confounding variables.Results: The exposure rate of zolpidem use in the glaucoma group was significantly higher than that of the control group (2.8% vs. 2.0%, P < 0.0001). The adjusted odds ratio (OR) of the risk of glaucoma for those with zolpidem use vs. those without was 1.19 (95% confidence interval [CI], 1.02-1.38). Compared to non-zolpidem users, zolpidem users with an average dose of more than 200 mg/year had significantly increased risk of glaucoma (OR 1.31, 95% CI 1.03-1.68).Conclusions: This study suggests that the use of zolpidem might increase the risk of subsequent glaucoma. Further confirmatory studies are recommended to clarify this important issue.

Breast Cancer Risk Factors among Ugandan Women at a Tertiary Hospital: A Case-Control Study

PubMed Central

Galukande, Moses; Wabinga, Henry; Mirembe, Florence; Karamagi, Charles; Asea, Alexzander

2016-01-01

Background Although East Africa, like other countries in sub-Saharan Africa, has a lower incidence of breast cancer than high-income countries, the disease rate is rising steeply in Africa; it has nearly tripled in the past few decades in Uganda. There is a paucity of studies that have examined the relation between reproductive factors and breast cancer risk factors in Ugandan women. Objective To determine breast cancer risk factors among indigenous Ugandan women. Methods This is a hospital-based unmatched case-control study. Interviews were conducted between 2011 and 2012 using structured questionnaires. Patients with histologyproven breast cancer were recruited over a 2-year period. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results A total of 350 women were recruited; 113 were cases and 237 were controls. The mean age was 47.5 years (SD 14) for the cases and 45.5 years (SD 14.1) for the controls. The odds of breast cancer risk seemed lower for those who breastfed (adjusted OR = 0.04; 95% CI: 0.01, 0.18). There was no significance for early age at first full-term birth (adjusted OR = 1.96; 95% CI: 0.97, 3.96; p = 0.061), and urban residence carried no increased odds of breast cancer either (p = 0.201). Conclusion Breastfeeding seems to be associated with reduced odds of breast cancer. PMID:27104645

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.

A community-based, case-control study of childhood stroke risk associated with congenital heart disease

PubMed Central

Fox, Christine K.; Sidney, Stephen; Fullerton, Heather J.

2014-01-01

Background and Purpose A better understanding of the stroke risk factors in children with congenital heart disease (CHD) could inform stroke prevention strategies. We analyzed pediatric stroke associated with CHD in a large community-based, case-control study. Methods From 2.5 million children (< 20 years) enrolled in a Northern California integrated healthcare plan, we identified ischemic and hemorrhagic strokes and randomly selected age and facility-matched stroke-free controls (3 per case). We determined exposure to CHD (diagnosed prior to stroke) and used conditional logistic regression to analyze stroke risk. Results CHD was identified in 15/412 cases (4%) versus 7/1,236 controls (0.6%). Children (28 days – 20 years) with CHD had 19-fold (Odds Ratio [OR] 19; 95% Confidence Interval [CI] 4.2, 83) increased stroke risk compared to controls. History of CHD surgery was associated with >30-fold increased risk of stroke (OR 31; CI 4, 241 compared to controls). After excluding peri-operative strokes, a history of CHD surgery still increased childhood stroke risk (OR 13; CI 1.5, 114). The majority of children with stroke and CHD were outpatient at the time of stroke, and almost half the cases who underwent cardiac surgery had their stroke >5 years after the most recent procedure. An estimated 7% of ischemic and 2% of hemorrhagic childhood strokes in the population were attributable to CHD. Conclusions CHD is an important childhood stroke risk factor. Children who undergo CHD surgery remain at elevated risk outside of the peri-operative period, and would benefit from optimized long-term stroke prevention strategies. PMID:25516197

[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

Entamoeba histolytica Infection in Female Sex Workers: A Matched Case-Control Study in Durango, Mexico

PubMed Central

Alvarado-Esquivel, Cosme; Sanchez-Anguiano, Luis Francisco; Hernandez-Tinoco, Jesus; Estrada-Martinez, Sergio; Perez-Alamos, Alma Rosa; Ramos-Nevarez, Agar; Cerrillo-Soto, Sandra Margarita; Guido-Arreola, Carlos Alberto

2017-01-01

Background Infection with Entamoeba histolytica (E. histolytica) can be potentially transmitted by sexual contact. The seroepidemiology of E. histolytica in female sex workers has not been studied. The aim of the study was to determine whether E. histolytica is associated with the occupation of female sex work. In addition, the correlates of E. histolytica seroprevalence in female sex workers were also investigated. Methods We performed an age- and gender-matched case-control study of 187 female sex workers and 374 women without sex work. Cases and controls were tested for the presence of E. histolytica IgG antibodies using a commercially available enzyme-linked immunoassay. Seroprevalence association with the characteristics of female sex workers was determined by bivariate analysis. Results Anti-E. histolytica IgG antibodies were found in five (2.7%) of 187 female sex workers and in 16 (4.3%) of 374 controls (odds ratios (OR) = 0.61; 95% confidence intervals (CI): 0.22 - 1.70; P = 0.34). Mean optical density of the immunoassay in seropositive cases and controls was 1.35 ± 0.93 and 0.73 ± 0.45, respectively (P = 0.05). Seroprevalence of E. histolytica infection did not vary significantly with age, education, socioeconomic level, or health status of sex workers. Seropositivity to E. histolytica did not correlate with work characteristics such as duration in the occupation, condom use, type of sex, or a history of sexually transmitted diseases, or with behavioral variables such as washing hands before eating, or consumption of untreated water. Conclusions Results indicate that female sex workers do not have an increased risk for E. histolytica infection in Durango City, Mexico. Further studies to determine the risk of infection with E. histolytica by sexual contact should be conducted. PMID:28611864

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.

Creating Unity through Celebrating Diversity: A Case Study That Explores the Impact of Music Education on Refugee Background Students

ERIC Educational Resources Information Center

Crawford, Renée

2017-01-01

This article reports the findings of a case study that investigated the impact of music education on students in an F-12 school in Victoria, Australia that is considered as having a high percentage of young people with a refugee background. Key findings from this research indicated that music education had a positive impact on this group of young…

Dietary Inflammatory Index and risk of multiple sclerosis in a case-control study from Iran

PubMed Central

Shivappa, Nitin; Hébert, James R.; Behrooz, Maryam; Rashidkhani, Bahram

2016-01-01

Background Diet and inflammation have been suggested to be important risk factors for multiple sclerosis (MS). Objectives In this study, we examined the ability of the dietary inflammatory index (DII) to predict MS in a case-control study conducted in Iran. Methods This study included 68 MS cases and 140 controls hospitalized for acute non-neoplastic diseases. The DII was computed based on dietary intake assessed by a previously validated food frequency questionnaire. Logistic regression models were used to estimate odds ratios (ORs) adjusted for age, energy, sex, BMI, season of birth, rubella history, history of routine exercise before MS, smoking and history of consumption of cow's mile in the first 2 years of life. Results Subjects with higher DII scores (i.e., with a more pro-inflammatory diet) had a higher risk of MS, with the DII being used as both a continuous variable (ORcontinuous 1.66, 95% confidence interval, (CI), 1.19-2.31; one unit increase corresponding to ≈15% of its range in the current study) and a categorical variable (ORdii>1.43 vs ≤ 1.43 2.68, 95%CI 1.15-6.26). Conclusions These results indicate that a pro-inflammatory diet is associated with increased risk of MS. PMID:27362443

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.

Study of environmental and genetic factors in children with craniosynostosis: A case-control study

PubMed Central

Barik, Mayadhar; Bajpai, Minu; Das, Rashmi Ranjan; Panda, Shasanka Shekhar

2013-01-01

Background: Craniosynostosis is a congenital defect that causes one or more sutures on an infant's skull to close earlier than normal. Though both genetic and environmental factors play a role in its pathogenesis, there is no published Indian data to verify this. Materials and Methods: In this case-control study, we investigated the association of craniosynostosis with parental age in 50 children with craniosynostosis attending the surgical outpatient department of a tertiary care institution in North India. Results: There was a significant association of craniosynostosis with advanced parental [OR 2.17 (95% CI 1.08 to 4.36)] but not maternal age. Education status of parents also revealed that those having a higher education had an increased risk of having a child with craniosynostosis [maternal education, OR 2.32 (95% CI 1.2 to 4.76); paternal education, OR 2.51 (95% CI 1.21 to 5.0)]. Molecular analysis by sequencing confirmed following amino-acid substitution in different Exons of the FGFR2 gene. Besides these, we found other novel identical mutations in FGFR2 gene in both syndromic and non-syndromic craniosynostoses. Conclusion: This is the first epidemiological study in India that provides evidence that, advanced paternal age and higher parental education level might be associated with an increased risk of craniosynostosis. New mutations were identified in cases of both syndromic and non-syndromic craniosynostosis. PMID:24082921

Early Urinary Markers of Diabetic Kidney Disease: A Nested Case-Control Study From the Diabetes Control and Complications Trial (DCCT)

PubMed Central

Kern, Elizabeth O; Erhard, Penny; Sun, Wanjie; Genuth, Saul; Weiss, Miriam F

2010-01-01

Background Urinary markers were tested as predictors of macroalbuminuria or microalbuminuria in type 1 diabetes. Study Design Nested case:control of participants in the Diabetes Control and Complications Trial (DCCT) Setting & Participants Eighty-seven cases of microalbuminuria were matched to 174 controls in a 1:2 ratio, while 4 cases were matched to 4 controls in a 1:1 ratio, resulting in 91 cases and 178 controls for microalbuminuria. Fifty-five cases of macroalbuminuria were matched to 110 controls in a 1:2 ratio. Controls were free of micro/macroalbuminuria when their matching case first developed micro/macroalbuminuria. Predictors Urinary N-acetyl-β-D-glucosaminidase, pentosidine, AGE fluorescence, albumin excretion rate (AER) Outcomes Incident microalbuminuria (two consecutive annual AER > 40 but <= 300 mg/day), or macroalbuminuria (AER > 300 mg/day) Measurements Stored urine samples from DCCT entry, and 1–9 years later when macroalbuminuria or microalbuminuria occurred, were measured for the lysosomal enzyme, N-acetyl-β-D-glucosaminidase, and the advanced glycosylation end-products (AGEs) pentosidine and AGE-fluorescence. AER and adjustor variables were obtained from the DCCT. Results Sub-microalbuminuric levels of AER at baseline independently predicted microalbuminuria (adjusted OR 1.83; p<.001) and macroalbuminuria (adjusted OR 1.82; p<.001). Baseline N-acetyl-β-D-glucosaminidase independently predicted macroalbuminuria (adjusted OR 2.26; p<.001), and microalbuminuria (adjusted OR 1.86; p<.001). Baseline pentosidine predicted macroalbuminuria (adjusted OR 6.89; p=.002). Baseline AGE fluorescence predicted microalbuminuria (adjusted OR 1.68; p=.02). However, adjusted for N-acetyl-β-D-glucosaminidase, pentosidine and AGE-fluorescence lost predictive association with macroalbuminuria and microalbuminuria, respectively. Limitations Use of angiotensin converting-enzyme inhibitors was not directly ascertained, although their use was proscribed during the

Genotyping and inflated type I error rate in genome-wide association case/control studies

PubMed Central

Sampson, Joshua N; Zhao, Hongyu

2009-01-01

Background One common goal of a case/control genome wide association study (GWAS) is to find SNPs associated with a disease. Traditionally, the first step in such studies is to assign a genotype to each SNP in each subject, based on a statistic summarizing fluorescence measurements. When the distributions of the summary statistics are not well separated by genotype, the act of genotype assignment can lead to more potential problems than acknowledged by the literature. Results Specifically, we show that the proportions of each called genotype need not equal the true proportions in the population, even as the number of subjects grows infinitely large. The called genotypes for two subjects need not be independent, even when their true genotypes are independent. Consequently, p-values from tests of association can be anti-conservative, even when the distributions of the summary statistic for the cases and controls are identical. To address these problems, we propose two new tests designed to reduce the inflation in the type I error rate caused by these problems. The first algorithm, logiCALL, measures call quality by fully exploring the likelihood profile of intensity measurements, and the second algorithm avoids genotyping by using a likelihood ratio statistic. Conclusion Genotyping can introduce avoidable false positives in GWAS. PMID:19236714

Appropriating Scientific Vocabulary in Chemistry Laboratories: A Multiple Case Study of Four Community College Students with Diverse Ethno-Linguistic Backgrounds

ERIC Educational Resources Information Center

Cink, Ruth B.; Song, Youngjin

2016-01-01

This multiple case study investigated how college students with diverse ethno-linguistic backgrounds used chemistry vocabulary as a way to look at their discursive identities and cultural border crossings during first semester general chemistry laboratories. The data were collected in two major forms: video-taped laboratory observations and…

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.

Case-control study on risk factors for acute hepatitis E in Germany, 2012 to 2014.

PubMed

Faber, Mirko; Askar, Mona; Stark, Klaus

2018-05-01

BackgroundNotified cases of hepatitis E have increased 40-fold in the past 10 years in Germany. Food safety is a major concern as hepatitis E virus (HEV) RNA has been detected in ready-to-eat retail-level food products. The objective of this case-control study was to assess risk factors for autochthonous symptomatic hepatitis E and explore reasons for delays in diagnosis. Methods: Demographic, clinical and exposure data from notified hepatitis E cases and individually matched population controls were collected in semi-standardised telephone interviews. Conditional logistic regression analysis was used to calculate matched odds ratios (mOR) and population attributable fractions (PAF). Results: In total, 270 cases and 1,159 controls were included (mean age 53 years, 61% men in both groups). Associated with disease were: consumption of undercooked pork liver, pork, wild boar meat, frankfurters, liver sausage and raw vegetables; contact with waste water (occupational) and various host factors (mORs between 1.9 and 34.1, p value < 0.03). PAF for frankfurters and liver sausage were 17.6%, and 23.6%, respectively. There were statistically significant differences in the clinical presentation and hospitalisation proportion of acute hepatitis E in men and women. Diagnosis was preceded by more invasive procedures in 29.2% of patients, suggesting that hepatitis E was not immediately considered as a common differential diagnosis. Conclusions: Our study suggests that there are indeed sex-specific differences in disease development and lends important epidemiological evidence to specific ready-to-eat pork products as a major source for autochthonous hepatitis E. A review of existing consumer recommendations and production methods may be indicated.

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).

Associations between heavy episodic drinking and alcohol related injuries: a case control study

PubMed Central

2013-01-01

Background Alcohol is a significant risk factor for injuries. This study addresses 1) whether the risk of alcohol related injury increases with frequency of heavy episodic drinking (HED) in a linear fashion, and 2) whether a small group of high risk drinkers accounts for the majority of alcohol related injuries. Methods We applied a case – control design. Cases were BAC positive injured patients (n = 534) and controls were respondents to a general population survey in Norway (n = 1947). Age and gender adjusted association between self-reported past year HED frequency and alcohol related injury risk was estimated in logistic regression models for all alcohol related injuries and for violence injuries and accident injuries separately. Results An increase in HED was associated with an increase in risk of alcohol related injury, resembling a linear risk function. The small fraction of high risk drinkers (6.6%) accounted for 41.6% of all alcohol related injuries, thus lending support to the validity of the prevention paradox. Conclusion There is a strong relationship between frequency of heavy episodic drinking and risk of alcohol related injuries, yet the majority of alcohol related injuries are found among drinkers who are not in the high risk group. PMID:24228707

A case-control study of determinants for high and low dental caries prevalence in Nevada youth

PubMed Central

2010-01-01

Background The main purpose of this study was to compare the 30% of Nevada Youth who presented with the highest Decayed Missing and Filled Teeth (DMFT) index to a cohort who were caries free and to national NHANES data. Secondly, to explore the factors associated with higher caries prevalence in those with the highest DMFT scores compared to the caries-free group. Methods Over 4000 adolescents between ages 12 and 19 (Case Group: N = 2124; Control Group: N = 2045) received oral health screenings conducted in public/private middle and high schools in Nevada in 2008/2009 academic year. Caries prevalence was computed (Untreated decay scores [D-Score] and DMFT scores) for the 30% of Nevada Youth who presented with the highest DMFT score (case group) and compared to the control group (caries-free) and to national averages. Bivariate and multivariate logistic regression was used to analyze the relationship between selected variables and caries prevalence. Results A majority of the sample was non-Hispanic (62%), non-smokers (80%), and had dental insurance (70%). With the exception of gender, significant differences in mean D-scores were found in seven of the eight variables. All variables produced significant differences between the case and control groups in mean DMFT Scores. With the exception of smoking status, there were significant differences in seven of the eight variables in the bivariate logistic regression. All of the independent variables remained in the multivariate logistic regression model contributing significantly to over 40% of the variation in the increased DMFT status. The strongest predictors for the high DMFT status were racial background, age, fluoridated community, and applied sealants respectively. Gender, second hand smoke, insurance status, and tobacco use were significant, but to a lesser extent. Conclusions Findings from this study will aid in creating educational programs and other primary and secondary interventions to help promote oral health

Body Mass Index and Breast Cancer Risk among Thai Premenopausal Women: a Case-Control Study

PubMed Central

Chaveepojnkamjorn, Wisit; Thotong, Rungsinoppadol; Sativipawee, Pratana; Pitikultang, Supachai

2017-01-01

Background: Breast cancer (BC) is the leading malignancy in women with high incidence and mortality worldwide. Obesity is one of several established risk factors for chronic diseases including cancer. The objective of this research was to determine the association of body mass index (BMI) with BC among Thai premenopausal women (TPW). Materials and Methods: A case-control study was conducted among TPW attending the National Cancer Institute in Bangkok, with 257 cases and 257 controls in 2013-2014. Cases and controls were matched by age (± 5 years), residential area and duration of attending. Data were collected with a questionnaire comprising 2 parts: part 1 socio-demographic characteristics, and part 2 health risk behavior and reproductive factors and BMI. The obtained data were analyzed using descriptive and analytic statistics with a computerized statistical package. Results: The study participants were mainly 40-44 years old (60 %) with an average age of 39 years. The major type of BC was the invasive ductal carcinoma (91.8%). On univariate analysis, risk factors for BC among the TPW were family history of BC, history of benign breast tumors, younger age at menarche, parity, miscarriage, contraceptive use, passive smoking, multivitamin use, and BMI (p<0.05). Multivariable conditional logistic regression analysis, controlling for possible confounding factors, revealed that a BMI 25-29.9 and ≥ 30 kg/m2 increased the risk of BC by a factor of 2.09 and 2.37 times, respectively (OR=2.09, 95%CI =1.09-3.97; OR=2.37, 95%CI =1.24-10.06). Conclusions: A surveillance system of obesity should be conducted in cooperation with information regarding physical activities and weight control among TPW as an essential measure to reduce BC risk. PMID:29172285

A multicentre case control study on complicated coeliac disease: two different patterns of natural history, two different prognoses

PubMed Central

2014-01-01

Background Coeliac disease is a common enteropathy characterized by an increased mortality mainly due to its complications. The natural history of complicated coeliac disease is characterised by two different types of course: patients with a new diagnosis of coeliac disease that do not improve despite a strict gluten-free diet (type A cases) and previously diagnosed coeliac patients that initially improved on a gluten-free diet but then relapsed despite a strict diet (type B cases). Our aim was to study the prognosis and survival of A and B cases. Methods Clinical and laboratory data from coeliac patients who later developed complications (A and B cases) and sex- and age-matched coeliac patients who normally responded to a gluten-free diet (controls) were collected among 11 Italian centres. Results 87 cases and 136 controls were enrolled. Complications tended to occur rapidly after the diagnosis of coeliac disease and cumulative survival dropped in the first months after diagnosis of complicated coeliac disease. Thirty-seven cases died (30/59 in group A, 7/28 in group B). Type B cases presented an increased survival rate compared to A cases. Conclusions Complicated coeliac disease is an extremely serious condition with a high mortality and a short survival. Survival depends on the type of natural history. PMID:25103857

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.

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.

Quieting Weinberg 5C: a case study in hospital noise control.

PubMed

MacLeod, Mark; Dunn, Jeffrey; Busch-Vishniac, Ilene J; West, James E; Reedy, Anita

2007-06-01

Weinberg 5C of Johns Hopkins Hospital is a very noisy hematological cancer unit in a relatively new building of a large medical campus. Because of the requirements for dealing with immuno-suppressed patients, options for introducing sound absorbing materials are limited. In this article, a case study of noise control in a hospital, the sound environment in the unit before treatment is described, the chosen noise control approach of adding custom-made sound absorbing panels is presented, and the impact of the noise control installation is discussed. The treatment of Weinberg 5C involved creating sound absorbing panels of 2-in.-thick fiberglass wrapped in an anti-bacterial fabric. Wallpaper paste was used to hold the fabric to the backing of the fiberglass. Installation of these panels on the ceiling and high on corridor walls had a dramatic effect. The noise on the unit (as measured by the equivalent sound pressure level) was immediately reduced by 5 dB(A) and the reverberation time dropped by a factor of over 2. Further, this drop in background noise and reverberation time understates the dramatic impact of the change. Surveys of staff and patients before and after the treatment indicated a change from viewing the unit as very noisy to a view of the unit as relatively quiet.

An outbreak of vancomycin-resistant Enterococcus faecium in an acute care pediatric hospital: Lessons from environmental screening and a case-control study

PubMed Central

Drews, Steven J; Richardson, Susan E; Wray, Rick; Freeman, Renee; Goldman, Carol; Streitenberger, Laurie; Stevens, Derek; Goia, Cristina; Kovach, Danuta; Brophy, Jason; Matlow, Anne G

2008-01-01

BACKGROUND The present study describes a vancomycin-resistant enterococci (VRE) outbreak investigation and a case-control study to identify risk factors for VRE acquisition in a tertiary care pediatric hospital. OBJECTIVE To report an outbreak investigation and a case-control study to identify risk factors for VRE colonization or infection in hospitalized children. METHODS Screening for VRE cases was performed by culture or polymerase chain reaction. A case-control study of VRE-colonized patients was undertaken. Environmental screening was performed using standard culture and susceptibility methods, with pulsed-field gel electrophoresis to determine relationships between VRE isolates. Statistical analysis was performed using SAS version 9.0 (SAS Institute Inc, USA). RESULTS Thirty-four VRE-positive cases were identified on 10 wards between February 28, 2005, and May 27, 2005. Pulsed-field gel electrophoresis analysis confirmed a single outbreak strain that was also isolated from a video game found on one affected ward. Multivariate analysis identified cephalosporin use as the major risk factor for VRE colonization. CONCLUSIONS In the present study outbreak, VRE colonization was significantly associated with cephalosporin use. Because shared recreational items and environmental surfaces may be colonized by VRE, they warrant particular attention in housekeeping protocols, particularly in pediatric institutions. PMID:19412380

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

Pretreatment Serum Concentrations of 25-Hydroxyvitamin D and Breast Cancer Prognostic Characteristics: A Case-Control and a Case-Series Study

PubMed Central

Yao, Song; Sucheston, Lara E.; Millen, Amy E.; Johnson, Candace S.; Trump, Donald L.; Nesline, Mary K.; Davis, Warren; Hong, Chi-Chen; McCann, Susan E.; Hwang, Helena; Kulkarni, Swati; Edge, Stephen B.; O'Connor, Tracey L.; Ambrosone, Christine B.

2011-01-01

Background Results from epidemiologic studies on the relationship between vitamin D and breast cancer risk are inconclusive. It is possible that vitamin D may be effective in reducing risk only of specific subtypes due to disease heterogeneity. Methods and Findings In case-control and case-series analyses, we examined serum concentrations of 25-hydroxyvitamin D (25OHD) in relation to breast cancer prognostic characteristics, including histologic grade, estrogen receptor (ER), and molecular subtypes defined by ER, progesterone receptor (PR) and HER2, among 579 women with incident breast cancer and 574 controls matched on age and time of blood draw enrolled in the Roswell Park Cancer Institute from 2003 to 2008. We found that breast cancer cases had significantly lower 25OHD concentrations than controls (adjusted mean, 22.8 versus 26.2 ng/mL, p<0.001). Among premenopausal women, 25OHD concentrations were lower in those with high- versus low-grade tumors, and ER negative versus ER positive tumors (p≤0.03). Levels were lowest among women with triple-negative cancer (17.5 ng/mL), significantly different from those with luminal A cancer (24.5 ng/mL, p = 0.002). In case-control analyses, premenopausal women with 25OHD concentrations above the median had significantly lower odds of having triple-negative cancer (OR = 0.21, 95% CI = 0.08–0.53) than those with levels below the median; and every 10 ng/mL increase in serum 25OHD concentrations was associated with a 64% lower odds of having triple-negative cancer (OR = 0.36, 95% CI = 0.22–0.56). The differential associations by tumor subtypes among premenopausal women were confirmed in case-series analyses. Conclusion In our analyses, higher serum levels of 25OHD were associated with reduced risk of breast cancer, with associations strongest for high grade, ER negative or triple negative cancers in premenopausal women. With further confirmation in large prospective studies, these findings could warrant

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.

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...

Study designs may influence results: the problems with questionnaire-based case-control studies on the epidemiology of glioma.

PubMed

Johansen, Christoffer; Schüz, Joachim; Andreasen, Anne-Marie Serena; Dalton, Susanne Oksbjerg

2017-03-28

Glioma is a rare brain tumour with a very poor prognosis and the search for modifiable factors is intense. We reviewed the literature concerning risk factors for glioma obtained in case-control designed epidemiological studies in order to discuss the influence of this methodology on the observed results. When reviewing the association between three exposures, medical radiation, exogenous hormone use and allergy, we critically appraised the evidence from both case-control and cohort studies. For medical radiation and hormone replacement therapy (HRT), questionnaire-based case-control studies appeared to show an inverse association, whereas nested case-control and cohort studies showed no association. For allergies, the inverse association was observed irrespective of study design. We recommend that the questionnaire-based case-control design be placed lower in the hierarchy of studies for establishing cause-and-effect for diseases such as glioma. We suggest that a state-of-the-art case-control study should, as a minimum, be accompanied by extensive validation of the exposure assessment methods and the representativeness of the study sample with regard to the exposures of interest. Otherwise, such studies cannot be regarded as 'hypothesis testing' but only 'hypothesis generating'. We consider that this holds true for all questionnaire-based case-control studies on cancer and other chronic diseases, although perhaps not to the same extent for each exposure-outcome combination.

Dietary Inflammatory Index and risk of esophageal squamous cell cancer in a case-control study from Iran

PubMed Central

Shivappa, Nitin; Hébert, James R.; Rashidkhani, Bahram

2015-01-01

Background Diet and inflammation have been suggested to be important risk factors for esophageal squamous cell carcinoma (ESCC). In this study, we examined the ability of the dietary inflammatory index (DII) to predict ESCC in a case-control study conducted in Iran. Methods This study included 47 ESCC cases and 96 controls hospitalized for acute non-neoplastic diseases. The DII was computed based on dietary intake assessed by a previously validated food frequency questionnaire. Logistic regression models were used to estimate odds ratios (ORs) adjusted for age, energy, sex, BMI, years of education, physical activity, smoking and gastro-esophageal reflux. Results Subjects with higher DII scores (i.e., with a more pro-inflammatory diet) had a higher risk of ESCC, with the DII being used as both a continuous variable (ORcontinuous 3.58, 95% confidence interval, CI, 1.76–7.26; one unit increase corresponding to ≈16% of its range in the current study) and a categorical variable (ORdii>1.20 vs ≤ 1.208.24, 95%CI 2.03–33.47). Conclusion These results indicate that a pro-inflammatory diet is associated with increased risk of ESCC. PMID:26400625

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.

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

Alcohol drinking and risk of Parkinson's disease: a case-control study in Japan

PubMed Central

2010-01-01

Background Although some epidemiologic studies found inverse associations between alcohol drinking and Parkinson's disease (PD), the majority of studies found no such significant associations. Additionally, there is only limited research into the possible interactions of alcohol intake with aldehyde dehydrogenase (ALDH) 2 activity with respect to PD risk. We examined the relationship between alcohol intake and PD among Japanese subjects using data from a case-control study. Methods From 214 cases within 6 years of PD onset and 327 controls without neurodegenerative disease, we collected information on "peak", as opposed to average, alcohol drinking frequency and peak drinking amounts during a subject's lifetime. Alcohol flushing status was evaluated via questions, as a means of detecting inactive ALHD2. The multivariate model included adjustments for sex, age, region of residence, smoking, years of education, body mass index, alcohol flushing status, presence of selected medication histories, and several dietary factors. Results Alcohol intake during peak drinking periods, regardless of frequency or amount, was not associated with PD. However, when we assessed daily ethanol intake separately for each type of alcohol, only Japanese sake (rice wine) was significantly associated with PD (adjusted odds ratio of ≥66.0 g ethanol per day: 3.39, 95% confidence interval: 1.10-11.0, P for trend = 0.001). There was no significant interaction of alcohol intake with flushing status in relation to PD risk. Conclusions We did not find significant associations between alcohol intake and PD, except for the daily amount of Japanese sake. Effect modifications by alcohol flushing status were not observed. PMID:21054827

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.

Diet-Related Risk Factors for Leprosy: A Case-Control Study

PubMed Central

Wagenaar, Inge; van Muiden, Lisanne; Alam, Khorshed; Bowers, Robert; Hossain, Md. Anwar; Kispotta, Kolpona; Richardus, Jan Hendrik

2015-01-01

Background Food shortage was associated with leprosy in two recent studies investigating the relation between socioeconomic factors and leprosy. Inadequate intake of nutrients due to food shortage may affect the immune system and influence the progression of infection to clinical leprosy. We aimed to identify possible differences in dietary intake between recently diagnosed leprosy patients and control subjects. Methods In a leprosy endemic area of Bangladesh, newly diagnosed leprosy patients and control subjects were interviewed about their socioeconomic situation, health and diet. Dietary intakes were recorded with a 24-hour recall, from which a Dietary Diversity Score (DDS) was calculated. Body Mass Index (BMI) was calculated and Household Food Insecurity Access Scale (HFIAS) was filled out for every participant. Using logistic regression, a univariate, block wise multivariate, and an integrated analysis were carried out. Results 52 leprosy cases and 100 control subjects were included. Food shortage was more common, dietary diversity was lower and household food insecurity was higher in the patient group. Patients consumed significantly less items from the DDS food groups ‘Meat and fish’ and ‘Other fruits and vegetables.’ Lower food expenditure per capita, lower BMI, lower DDS and absence of household food stocks are the main factors associated with an increased risk of having leprosy. Conclusion Low income families have only little money to spend on food and consequently have a low intake of highly nutritious non-rice foods such as meat, fish, milk, eggs, fruits and vegetables. Development of clinical leprosy could be explained by deficiencies of the nutrients that these foods normally provide. PMID:25965879

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).

Comparison of Estimates between Cohort and Case-Control Studies in Meta-Analyses of Therapeutic Interventions: A Meta-Epidemiological Study.

PubMed

Lanza, Amy; Ravaud, Philippe; Riveros, Carolina; Dechartres, Agnes

2016-01-01

Observational studies are increasingly being used for assessing therapeutic interventions. Case-control studies are generally considered to have greater risk of bias than cohort studies, but we lack evidence of differences in effect estimates between the 2 study types. We aimed to compare estimates between cohort and case-control studies in meta-analyses of observational studies of therapeutic interventions by using a meta-epidemiological study. We used a random sample of meta-analyses of therapeutic interventions published in 2013 that included both cohort and case-control studies assessing a binary outcome. For each meta-analysis, the ratio of estimates (RE) was calculated by comparing the estimate in case-control studies to that in cohort studies. Then, we used random-effects meta-analysis to estimate a combined RE across meta-analyses. An RE < 1 indicated that case-control studies yielded larger estimates than cohort studies. The final analysis included 23 meta-analyses: 138 cohort and 133 case-control studies. Treatment effect estimates did not significantly differ between case-control and cohort studies (combined RE 0.97 [95% CI 0.86-1.09]). Heterogeneity was low, with between-meta-analysis variance τ2 = 0.0049. Estimates did not differ between case-control and prospective or retrospective cohort studies (RE = 1.05 [95% CI 0.96-1.15] and RE = 0.99 [95% CI, 0.83-1.19], respectively). Sensitivity analysis of studies reporting adjusted estimates also revealed no significant difference (RE = 1.03 [95% CI 0.91-1.16]). Heterogeneity was also low for these analyses. We found no significant difference in treatment effect estimates between case-control and cohort studies assessing therapeutic interventions.

Toxoplasma gondii seroprevalence and association with equine protozoal myeloencephalitis: A case-control study of Californian horses.

PubMed

James, K E; Smith, W A; Packham, A E; Conrad, P A; Pusterla, N

2017-06-01

While toxoplasmosis is not commonly considered a clinical disease of equines, previous seroprevalence studies have reported differing background rates of Toxoplasma gondii infection in horses globally. The objective of this study was to evaluate possible associations between T. gondii seroprevalence and clinical signs of equine protozoal myeloencephalitis (EPM) in horses. Using a case-control study design, 720 Californian horses with neurologic signs compatible with EPM were compared to healthy, non-neurologic horses for the presence of T. gondii antibodies (using indirect fluorescent antibody tests [IFAT]). Toxoplasma gondii seroprevalence among cases and controls was determined at standard serum cut-offs: 40, 80, 160, 320, and 640. At a T. gondii titre cut-off of 320, horses with clinical signs compatible with EPM had 3.55 times the odds of a seropositive test compared to those without clinical signs (P<0.01) when adjusted for covariates. When restricted to the autumn season and at the same titre cut-off, an EPM suspect horse had 6.4 times the odds of testing seropositive to T. gondii, compared to non-neurologic horses. The association between high T. gondii titres and clinical signs compatible with EPM is potentially reflective of toxoplasmosis in equines. Serologic testing of cerebrospinal fluid and isolation of T. gondii in EPM suspect cases should be considered. Future studies investigating the relationship between T. gondii and EPM are warranted. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Deaths certified as asthma and use of medical services: a national case-control study

PubMed Central

Sturdy, P; Butland, B; Anderson, H; Ayres, J; Bland, J; Harrison, B; Peckitt, C; Victor, C; on, b

2005-01-01

Background: Studies have linked asthma death to either increased or decreased use of medical services. Methods: A population based case-control study of asthma deaths in 1994–8 was performed in 22 English, six Scottish, and five Welsh health authorities/boards. All 681 subjects who died were under the age of 65 years with asthma in Part I on the death certificates. After exclusions, 532 hospital controls were matched to 532 cases for age, district, and date of asthma admission/death. Data were extracted blind from primary care records. Results: The median age of the subjects who died was 53 years; 60% of cases and 64% of controls were female. There was little difference in outpatient attendance (55% and 55%), hospital admission for asthma (51% and 54%), and median inpatient days (20 days and 15 days) in the previous 5 years. After mutual adjustment and adjustment for sex, using conditional logistic regression, three variables were independently associated with asthma death: fewer general practice contacts (odds ratio 0.82 (95% confidence interval (CI) 0.74 to 0.91) per 5 contacts) in the previous year, more home visits (1.14 (95% CI 1.08 to 1.21) per visit) in the previous year, and fewer peak expiratory flow recordings (0.83 (95% CI 0.74 to 0.92) per occasion) in the previous 3 months. These associations were similar after adjustment for markers of severity, psychosocial factors, systemic steroids, short acting bronchodilators and antibiotics, although the association with peak flow was weakened and just lost significance. Conclusion: Asthma death is associated with less use of primary care services. Both practice and patient factors may be involved and a better understanding of these may offer possibilities for reducing asthma death. PMID:16055628

Oral Streptococcal Endocarditis, Oral Hygiene Habits, and Recent Dental Procedures: A Case-Control Study.

PubMed

Duval, Xavier; Millot, Sarah; Chirouze, Catherine; Selton-Suty, Christine; Moby, Vanessa; Tattevin, Pierre; Strady, Christophe; Euvrard, Edouard; Agrinier, Nelly; Thomas, Daniel; Hoen, Bruno; Alla, François

2017-06-15

We aimed to compare oral hygiene habits, orodental status, and dental procedures in patients with infective endocarditis (IE) according to whether the IE-causing microorganism originated in the oral cavity. We conducted an assessor-blinded case-control study in 6 French tertiary-care hospitals. Oral hygiene habits were recorded using a self-administered questionnaire. Orodental status was analyzed by trained dental practitioners blinded to the microorganism, using standardized clinical examination and dental panoramic tomography. History of dental procedures was obtained through patient and dentist interviews. Microorganisms were categorized as oral streptococci or nonoral pathogens using an expert-validated list kept confidential during the course of the study. Cases and controls had definite IE caused either by oral streptococci or nonoral pathogens, respectively. Participants were enrolled between May 2008 and January 2013. Cases (n = 73) were more likely than controls (n = 192) to be aged <65 years (odds ratio [OR], 2.85; 95% CI, 1.41-5.76), to be female (OR, 2.62; 95% CI, 1.20-5.74), to have native valve disease (OR, 2.44; 95% CI, 1.16-5.13), to use toothpicks, dental water jet, interdental brush, and/or dental floss (OR, 3.48; 95% CI, 1.30-9.32), and to have had dental procedures during the prior 3 months (OR, 3.31; 95% CI, 1.18-9.29), whereas they were less likely to brush teeth after meals. The presence of gingival inflammation, calculus, and infectious dental diseases did not significantly differ between groups. Patients with IE caused by oral streptococci differ from patients with IE caused by nonoral pathogens regarding background characteristics, oral hygiene habits, and recent dental procedures, but not current orodental status. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com

Knee movement patterns of injured and uninjured adolescent basketball players when landing from a jump: A case-control study

PubMed Central

Louw, Quinette; Grimmer, Karen; Vaughan, Christopher

2006-01-01

Background A common knee injury mechanism sustained during basketball is landing badly from a jump. Landing is a complex task and requires good coordination, dynamic muscle control and flexibility. For adolescents whose coordination and motor control has not fully matured, landing badly from a jump can present a significant risk for injury. There is currently limited biomechanical information regarding the lower limb kinetics of adolescents when jumping, specifically regarding jump kinematics comparing injured with uninjured adolescents. This study reports on an investigation of biomechanical differences in landing patterns of uninjured and injured adolescent basketball players. Methods A matched case-control study design was employed. Twenty-two basketball players aged 14–16 years participated in the study: eleven previously knee-injured and eleven uninjured players matched with cases for age, gender, weight, height and years of play, and playing for the same club. Six high-speed, three-dimensional Vicon 370 cameras (120 Hz), Vicon biomechanical software and SAS Version 8 software were employed to analyse landing patterns when subjects performed a "jump shot". Linear correlations determined functional relationships between the biomechanical performance of lower limb joints, and paired t-tests determined differences between the normalised peak biomechanical parameters. Results The average peak vertical ground reaction forces between the cases and controls were similar. The average peak ground reaction forces between the cases and controls were moderately correlated (r = -0.47). The control (uninjured) players had significantly greater hip and knee flexion angles and significantly greater eccentric activity on landing than the uninjured cases (p < 0.01). Conclusion The findings of the study indicate that players with a history of knee injuries had biomechanically compromised landing techniques when compared with uninjured players matched for gender, age and club

Asthma in changing environments - chances and challenges of international research collaborations between South America and Europe - study protocol and description of the data acquisition of a case-control-study

PubMed Central

2010-01-01

Background Asthma in children is an emerging public health problem in South America. So far, research in this part of the world is limited. This paper presents the methodology and description of the data acquisition of an asthma case-control study conducted in the Central South of Chile. Methods/Design A hospital-based case-control study about asthma (188 cases, 294 controls) in children (6-15 years) was carried out in Valdivia, Chile between November 2008 and December 2009. Data on asthma risk factors were collected by computer-assisted personal interview using validated questions from e.g. ISAAC phase II. Data on household dust exposure (endotoxin, allergen analyses), skin prick tests to most common allergens, stool examinations for parasitic infection, and blood samples (total IgE, genetics) were collected. Additionally, 492 randomly chosen blood donors were recruited in order to assess allele frequencies in the population of Valdivia. Discussion Overall 1,173 participants were contacted. Response was 82% among cases and 65% among controls. Atopic sensitization was high (78% among cases, 47% among controls). Cases had a statistically significantly (p < .0001) increased self-reported 12-month prevalence of symptoms of rhinitis (82% vs. 51%) and wheeze (68% vs. 16%). The study is well placed to address current hypotheses about asthma and its correlates in the South American context. Results of this study might help develop novel, innovative and individualized prevention strategies in countries in transition with respect to the South American context. PMID:20718949

Demographic profile of families and children in the Study to Explore Early Development (SEED): Case-control study of autism spectrum disorder

PubMed Central

DiGuiseppi, Carolyn G.; Daniels, Julie L.; Fallin, Daniele M.; Rosenberg, Steven A.; Schieve, Laura A.; Thomas, Kathleen C.; Windham, Gayle C.; Goss, Cynthia W.; Soke, Gnakub N.; Currie, Dustin W.; Singer, Alison B.; Lee, Li-Ching; Bernal, Pilar; Croen, Lisa A.; Miller, Lisa A.; Pinto-Martin, Jennifer A.; Young, Lisa M.; Schendel, Diana E.

2016-01-01

Background The Study to Explore Early Development (SEED) is designed to enhance knowledge of autism spectrum disorder characteristics and etiologies. Objective This paper describes the demographic profile of enrolled families and examines sociodemographic differences between children with autism spectrum disorder and children with other developmental problems or who are typically developing. Methods This multi-site case-control study used health, education, and birth certificate records to identify and enroll children aged 2–5 years into one of three groups: 1) cases (children with autism spectrum disorder), 2) developmental delay or disorder controls, or 3) general population controls. Study group classification was based on sampling source, prior diagnoses, and study screening tests and developmental evaluations. The child's primary caregiver provided demographic characteristics through a telephone (or occasionally face-to-face) interview. Groups were compared using ANOVA, chi-squared test, or multinomial logistic regression as appropriate. Results Of 2768 study children, sizeable proportions were born to mothers of non-White race (31.7%), Hispanic ethnicity (11.4%), and foreign birth (17.6%); 33.0% of households had incomes below the US median. The autism spectrum disorder and population control groups differed significantly on nearly all sociodemographic parameters. In contrast, the autism spectrum disorder and developmental delay or disorder groups had generally similar sociodemographic characteristics. Conclusions SEED enrolled a sociodemographically diverse sample, which will allow further, in-depth exploration of sociodemographic differences between study groups and provide novel opportunities to explore sociodemographic influences on etiologic risk factor associations with autism spectrum disorder and phenotypic subtypes. PMID:26917104

[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.

Misclassification of Case-Control Studies in Neurosurgery and Proposed Solutions.

PubMed

Esene, Ignatius Ngene; Mbuagbaw, Lawrence; Dechambenoit, Gilbert; Reda, Wael; Kalangu, Kazadi K

2018-04-01

Case-control studies (CCS) and cohort studies (CS) are common research designs in neurosurgery. But the term case-control study is frequently misused in the neurosurgical literature, with many articles reported as CCS, even although their methodology does not respect the basic components of a CCS. We sought to estimate the extent of these discrepancies in neurosurgical literature, explore factors contributing to mislabeling, and shed some light on study design reporting. We identified 31 top-ranking pure neurosurgical journals and searched them for articles reported as CCS, either in the title or in the abstract. The articles were read to determine if they really were CCS according to STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines. Article assessment was conducted in duplicate (agreement [κ statistics] = 99.82%). Two hundred and twenty-four articles met our inclusion criteria, 133 of which (59.38%) correctly labeled the case-control design, whereas 91 (40.62%) misclassified this study design. Cohort studies (CS) were the most common design mislabeled as case-control studies in 76 articles (33.93%), 57 of which (25.45%) were retrospective CS. The mislabeling of CCS impairs the appropriate indexing, classification, and sorting of evidence. Mislabeling CS for CCS leads to a downgrading of evidence as CS represent the highest level of evidence for observational studies. Odds ratios instead of relative risk are reported for these studies, resulting in a distortion of the measurement of the effect size, compounded when these are summarized in systematic reviews and pooled in meta-analyses. Many studies reported as CCS are not true CCS. Reporting guidelines should include items that ensure that studies are labeled correctly. STROBE guidelines should be implemented in assessment of observational studies. Researchers in neurosurgery need better training in research methods and terminology. We also recommend accrued vigilance from

[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.

Serum Interleukin-6 as a Serologic Marker of Chronic Periapical Lesions: A Case-control Study

PubMed Central

Abdolsamadi, Hamid Reza; Vahedi, Mohammad; Esmaeili, Farzad; Nazari, Shahrzad; Abdollahzadeh, Shermin

2008-01-01

Background and aims Chronic periapical disease with pulpal origin is an inflammatory condition caused by bacterial infection. Chronic infection could affect general health by increasing the production of cytokines such as interleukin-6 (IL-6) that probably play a role in pathogenesis of pulpal and periapical diseases. The aim of the present study was a comparative evaluation of the level of serum IL 6 in patients with periapical lesions and healthy controls. Materials and methods This analytical case-control study included 40 patients with chronic peri-apical lesions and 40 individuals without any oral diseases. All of the participants were in good general health. After obtaining an informed consent, clinical and radiographic examinations were carried out and blood samples were collected. Serum IL-6 was measured using ELISA. Data were analyzed using t-test by SPSS 14.0 computer software. Results Serum IL-6 concentration was significantly higher in test group compared to the controls (P < 0.05). Conclusion The results of the present study indicate that IL-6 produced in periapical lesions may serve as a marker of pathologic inflammatory activities in chronic periapical lesions. PMID:23289057

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

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.

Sexual behaviour among casual workers in an international nightlife resort: a case control study

PubMed Central

Hughes, Karen; Bellis, Mark A

2006-01-01

Background Young holidaymakers report increased sexual risk-taking abroad, yet little is currently known about the sexual behaviour of those who extend time abroad through casual work. Methods Information on sexual behaviour was collected via an anonymous questionnaire administered to British bar and nightclub workers in Ibiza (cases, n = 92) and British people visiting Ibiza for holiday purposes only (controls, n = 868). Results Four in five (80.5%) cases who arrived in Ibiza without a partner had sex during their stay and of these two thirds (65.5%) had unprotected sex. Cases were more likely to report sexual risk-taking in Ibiza than controls and reported greater numbers of sexual partners prior to their visit. However, they had fewer sexual partners per week of stay. Conclusion Casual workers in bars and nightclubs abroad are a key risk group for sexual health and a potential conduit for the international spread of sexually transmitted infections. While they are an important target group for sexual health promotion, appropriately trained they are also ideally placed to deliver sexual health interventions to other young travellers. PMID:16504040

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.

Geographic Region, Weather, Pilot Age and Air Carrier Crashes: a Case-Control Study

PubMed Central

Li, Guohua; Pressley, Joyce C.; Qiang, Yandong; Grabowski, Jurek G.; Baker, Susan P.; Rebok, George W.

2009-01-01

Background Information about risk factors of aviation crashes is crucial for developing effective intervention programs. Previous studies assessing factors associated with crash risk were conducted primarily in general aviation, air taxis and commuter air carriers. Methods A matched case-control design was used to examine the associations of geographic region, basic weather condition, and pilot age with the risk of air carrier (14 CFR Part 121) crash involvement. Cases (n=373) were air carrier crashes involving aircraft made by Boeing, McDonnell Douglas, and Airbus, recorded in the National Transportation Safety Board’s aviation crash database during 1983 through 2002, and controls (n=746) were air carrier incidents involving aircraft of the same three makes selected at random from the Federal Aviation Administration’s aviation incident database. Each case was matched with two controls on the calendar year when the index crash occurred. Conditional logistic regression was used for statistical analysis. Results With adjustment for basic weather condition, pilot age, and total flight time, the risk of air carrier crashes in Alaska was more than three times the risk for other regions [adjusted odds ratio (OR) 3.18, 95% confidence interval (CI) 1.35 – 7.49]. Instrument meteorological conditions were associated with an increased risk for air carrier crashes involving pilot error (adjusted OR 2.26, 95% CI 1.15 – 4.44) and a decreased risk for air carrier crashes without pilot error (adjusted OR 0.57, 95% CI 0.40 – 0.87). Neither pilot age nor total flight time was significantly associated with the risk of air carrier crashes. Conclusions The excess risk of air carrier crashes in Alaska and the effect of adverse weather on pilot-error crashes underscore the importance of environmental hazards in flight safety. PMID:19378910

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.

Physical activity domains and risk of gastric adenocarcinoma in the MCC-Spain case-control study

PubMed Central

Chirlaque, María Dolores; Molina, Antonio J.; Amiano, Pilar; Martín, Vicente; Fernández-Villa, Tania; Pérez-Gómez, Beatriz; Moreno, Víctor; Burgui, Rosana; Gómez-Acebo, Inés; Ramos-Lora, Manuel; Fernández-Tardón, Guillermo; Peiró, Rosana; Olmedo-Requena, Rocío; Pollán, Marina; Kogevinas, Manolis; Castaño-Vinyals, Gemma; Aragonés, Nuria

2017-01-01

Background Evidence for a protective role of physical activity against development of stomach cancer is yet inconclusive. We studied the association of domain-specific physical activity and the risk of gastric adenocarcinoma (GAC), by site and histology, in the MCC-Spain case-control study. Methods 428 histologically confirmed GAC cases (67% men) including the gastro-esophageal region and 3225 controls were included. Cases were recruited in hospitals from 10 different Spanish regions, whereas population controls were randomly selected within the respective hospitals' catchment areas. A physical activity (PA) questionnaire was used to gather information on household and recreational activities, allowing estimation of PA volume (in metabolic equivalents (MET)-min/week). Participants also reported the intensity of working PA and daily sitting time. Questionnaire data on diet, lifestyles and clinical variables including Helicobacter pylori serology were available. Adjusted odds ratios (OR) of GAC were estimated for domains of physical activity, stratifying by sex, site (cardia vs. non-cardia), and Lauren classification (intestinal vs. diffuse). Results Household physical activity (HPA) showed a strong inverse association with GAC, observed for both cardia and non-cardia tumours. Risk of overall gastric cancer was 50% lower risk among participants in the highest HPA category (OR = 0.50, 95%CI: 0.38, 0.66). Recreational physical activity (RPA) was also associated with lower overall GAC risk (OR = 0.68, 95% CI: 0.52, 0.88), particularly at moderate levels of intensity such as walking (OR = 0.61, 95% CI: 0.46, 0.79). The protective effect of RPA was strongest for non-cardia tumours. Sedentary time was not related to GAC risk (p-trend = 0.392), but the potential protective effect of RPA was restricted to non-sedentary participants. Conclusions Both household and recreational physical activities were independently related to lower GAC risk in the MCC-Spain study. PMID

Metformin for Primary Colorectal Cancer Prevention in Diabetic Patients: A Case-Control Study in a US Population

PubMed Central

Sehdev, Amikar; Shih, Ya-Chen T.; Vekhter, Benjamin; Bissonnette, Marc; Olopade, Olufunmilayo I.; Polite, Blase

2016-01-01

Background Emerging evidence from observational studies suggests that metformin may be beneficial in the primary prevention of colorectal cancer (CRC). However, none of these were conducted in a US population. Since environmental factors, such as Western diet and obesity, are implicated in the causation of CRC, we conducted a large case control study to assess the effects of metformin on CRC incidence in a US population. Methods MarketScan® databases were used to identify diabetic patients with CRC. A case was defined as having an incident diagnosis of CRC. Up to two controls matched for age, sex and geographical region, were selected for each case. Metformin exposure was assessed by prescription tracking in the 12 months period prior to the index date. Conditional logistic regression was used to adjust for multiple potential confounders and to calculate adjusted odds ratios (AOR). Results The mean age of participants was 55 and 57 years in the control and case group, respectively (p=1.0). Sixty percent of the study participants were males and 40% were females in each group. In the multivariable model, any metformin use was associated with 15% reduced odds of CRC (AOR, 0.85, 95% confidence interval (CI), 0.76–0.95, p<0.007). After adjusting for health-care utilization the beneficial effect of metformin was reduced to 12% (AOR, 0.88, 95% CI, 0.77–1.00, p=0.05). The dose-response analyses showed no significant association with metformin dose, duration or total exposure. Conclusions Metformin use is associated with reduced risk of developing CRC among diabetic patients in the US population. PMID:25424411

[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.

Associated Factors and Outcome of Uterine Rupture at Suhul General Hospital, Shire Town, North West Tigray, Ethiopia 2016: A Case-Control Study

PubMed Central

Mulat Aweke, Amlaku; Eshetie Wondie, Tewodrose

2017-01-01

Background Uterine rupture is tearing of the uterine wall during pregnancy or delivery. It may extend to partial or whole thickness of the uterine wall. It is usually a case where obstetric care is poor. In extensive damage, death of the baby and sometimes even maternal death are evident. Objective This study assesses associated factors and outcome of uterine rupture at Suhul General Hospital, Tigray Region, Ethiopia, 2016. Methodology A case-control study was conducted by review of data from September 2012 to August 2016. A total of 336 samples were studied after calculating by EPI-INFO using proportion of multiparity (53%) and ratio of 1 : 2 for cases and controls, respectively. Analysis was done using SPSS version 20. Bivariate and multivariate logistic regression was applied with p < 0.05. Result ANC, grand multiparity, malpresentation, and obstructed labor had association, but previous cesarean delivery was not significant. Perinatal mortality was 105 (93%) versus 13 (5.8%) in cases and controls, respectively. Anemia was highest for both groups (53.7% versus 32.1%). Conclusion Majority of uterine rupture is attributed to prolonged or obstructed labor. Cases of uterine rupture had prompt management preventing maternal mortality, but burden of perinatal death is still high. PMID:29403533

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.

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.

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

Ethnic variations in severe maternal morbidity in the UK- a case control study.

PubMed

Nair, Manisha; Kurinczuk, Jennifer J; Knight, Marian

2014-01-01

Previous studies showed a higher risk of maternal morbidity amongst black and other minority ethnic (BME) groups, but were unable to investigate whether this excess risk was concentrated within specific BME groups in the UK. Our aim was to analyse the specific risks and to investigate reasons for any disparity. Unmatched case-control analysis using data from the United Kingdom Obstetric Surveillance System (UKOSS), February 2005-January 2013. Cases were 1,753 women who experienced severe morbidity during the peripartum period. Controls were 3,310 women who delivered immediately before the cases in the same hospital. Multivariable logistic regression modelling was used to adjust for known confounders and to understand their effects. Compared with white European women, the odds of severe maternal morbidity were 83% higher among black African women (adjusted odds ratio (aOR) = 1.83; 95% Confidence Interval (CI) = 1.39-2.40), 80% higher among black Caribbean (aOR = 1.80; 95% CI = 1.14-2.82), 74% higher in Bangladeshi (aOR = 1.74; 95% CI = 1.05-2.88), 56% higher in other non-whites (non-Asian) (aOR = 1.56; 95% CI = 1.05-2.33) and 43% higher among Pakistani women (aOR = 1.43; 95% CI = 1.07-1.92). There was no evidence of substantial confounding. Anaemia in current pregnancy, previous pregnancy problems, inadequate utilisation of antenatal care, pre-existing medical conditions, parity>3, and being younger and older were independent risk factors but, the odds of severe maternal morbidity did not differ by socioeconomic status, between smokers and non-smokers or by BMI. This national study demonstrates an increased risk of severe maternal morbidity among women of ethnic minority backgrounds which could not be explained by known risk factors for severe maternal morbidity.

Vitamin D–binding protein and pancreatic cancer: a nested case-control study12345

PubMed Central

Piper, Marina R; Freedman, D Michal; Robien, Kim; Kopp, William; Rager, Helen; Horst, Ronald L

2015-01-01

Background: Vitamin D–binding protein (DBP) is the primary carrier of 25-hydroxyvitamin D [25(OH)D] in the circulation. One prospective study in male smokers found a protective association between DBP and pancreatic cancer, particularly among men with higher 25(OH)D concentrations. Objective: The objective was to examine the association between DBP and pancreatic cancer risk in an American population. Design: We conducted a nested case-control study in the Prostate, Lung, Colorectal, and Ovarian Cancer screening trial cohort of men and women aged 55–74 y at baseline. Between 1993 and 2010, 295 incident pancreatic adenocarcinoma cases were reported (follow-up to 15.1 y). Two controls (n = 590) were matched to each case by age, race, sex, and month of blood draw. We calculated smoking- and diabetes-adjusted ORs and 95% CIs with the use of conditional logistic regression. Results: DBP concentration was not significantly associated with pancreatic cancer overall [highest (≥7149.4 nmol/L) vs. lowest (<3670.4 nmol/L) quintile; OR: 1.75; 95% CI: 0.91, 3.37; P-trend = 0.25]. For serum 25(OH)D compared with the referent (50 to <75 nmol/L), individuals in the highest group had a significantly higher risk (≥100 nmol/L; OR: 3.23; 95% CI: 1.24, 8.44), whereas those in the lowest group had no significant association (<25 nmol/L; OR: 2.50; 95% CI: 0.92, 6.81). Further adjustment for DBP did not alter this association. Conclusion: Our results do not support the hypothesis that serum DBP or 25(OH)D plays a protective role in pancreatic cancer. This trial was registered at clinicaltrials.gov as NCT00339495. PMID:25904602

Risk of Gastric Cancer by Water Source: Evidence from the Golestan Case-Control Study

PubMed Central

Eichelberger, Laura; Murphy, Gwen; Etemadi, Arash; Abnet, Christian C.; Islami, Farhad; Shakeri, Ramin; Malekzadeh, Reza; Dawsey, Sanford M.

2015-01-01

Background Gastric cancer (GC) is the world’s fifth most common cancer, and the third leading cause of cancer-related death. Over 70% of incident cases and deaths occur in developing countries. We explored whether disparities in access to improved drinking water sources were associated with GC risk in the Golestan Gastric Cancer Case Control Study. Methods and Findings 306 cases and 605 controls were matched on age, gender, and place of residence. We conducted unconditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CI), adjusted for age, gender, ethnicity, marital status, education, head of household education, place of birth and residence, homeownership, home size, wealth score, vegetable consumption, and H. pylori seropositivity. Fully-adjusted ORs were 0.23 (95% CI: 0.05–1.04) for chlorinated well water, 4.58 (95% CI: 2.07–10.16) for unchlorinated well water, 4.26 (95% CI: 1.81–10.04) for surface water, 1.11 (95% CI: 0.61–2.03) for water from cisterns, and 1.79 (95% CI: 1.20–2.69) for all unpiped sources, compared to in-home piped water. Comparing unchlorinated water to chlorinated water, we found over a two-fold increased GC risk (OR 2.37, 95% CI: 1.56–3.61). Conclusions Unpiped and unchlorinated drinking water sources, particularly wells and surface water, were significantly associated with the risk of GC. PMID:26023788

Endemic cryptosporidiosis and exposure to municipal tap water in persons with acquired immunodeficiency syndrome (AIDS): A case-control study

PubMed Central

Aragón, Tomás J; Novotny, Suzanne; Enanoria, Wayne; Vugia, Duc J; Khalakdina, Asheena; Katz, Mitchell H

2003-01-01

Background In persons with acquired immunodeficiency syndrome (AIDS), Cryptosporidium parvum causes a prolonged, severe diarrheal illness to which there is no effective treatment, and the risk of developing cryptosporidiosis from drinking tap water in non-outbreak settings remains uncertain. To test the hypothesis that drinking tap water was associated with developing cryptosporidiosis, we conducted a matched case-control study among persons with AIDS in San Francisco. Methods Among patients reported to the San Francisco AIDS Registry from May 1996 through September 1998, we compared patients who developed cryptosporidiosis to those who did not. Cases were individually matched to controls based on age, sex, race/ethnicity, CD4+ T lymphocyte count, date of CD4+ count, and date of case diagnosis. Population attributable fractions (PAFs) were calculated. Results The study consisted of 49 cases and 99 matched controls. In the multivariable analysis with adjustments for confounders, tap water consumption inside and outside the home at the highest exposure categories was associated with the occurrence of cryptosporidiosis (inside the home: odds ratio (OR), 6.76; 95% CI 1.37–33.5, and outside the home: OR 3.16; 95% CI 1.23–8.13). The PAF was 85%; that is, the proportion of cases of cryptosporidiosis in San Francisco AIDS patients attributable to tap water consumption could have been as high as 85%. Conclusions Although the results from this observational study cannot be considered definitive, until there is more data, we recommend persons with AIDS, especially those with compromised immune systems, consider avoiding tap water. PMID:12515584

Polymorphisms of genes coding for ghrelin and its receptor in relation to colorectal cancer risk: a two-step gene-wide case-control study

PubMed Central

2010-01-01

Background Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor (GHSR), has two major functions: the stimulation of the growth hormone production and the stimulation of food intake. Accumulating evidence also indicates a role of ghrelin in cancer development. Methods We conducted a case-control study to examine the association of common genetic variants in the genes coding for ghrelin (GHRL) and its receptor (GHSR) with colorectal cancer risk. Pairwise tagging was used to select the 11 polymorphisms included in the study. The selected polymorphisms were genotyped in 680 cases and 593 controls from the Czech Republic. Results We found two SNPs associated with lower risk of colorectal cancer, namely SNPs rs27647 and rs35683. We replicated the two hits, in additional 569 cases and 726 controls from Germany. Conclusion A joint analysis of the two populations indicated that the T allele of rs27647 SNP exerted a protective borderline effect (Ptrend = 0.004). PMID:20920174

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

Relationship between obesity, ethnicity and risk of late stillbirth: a case control study

PubMed Central

2011-01-01

Background In high income countries there has been little improvement in stillbirth rates over the past two decades. Previous studies have indicated an ethnic disparity in the rate of stillbirths. This study aimed to determine whether maternal ethnicity is independently associated with late stillbirth in New Zealand. Methods Cases were women with a singleton, late stillbirth (≥28 weeks' gestation) without congenital abnormality, born between July 2006 and June 2009 in Auckland, New Zealand. Two controls with ongoing pregnancies were randomly selected at the same gestation at which the stillbirth occurred. Women were interviewed in the first few weeks following stillbirth, or at the equivalent gestation for controls. Detailed demographic data were recorded. The study was powered to detect an odds ratio of 2, with a power of 80% at the 5% level of significance, given a prevalence of the risk factor of 20%. A multivariable regression model was developed which adjusted for known risk factors for stillbirth, as well as significant risk factors identified in the current study, and adjusted odds ratios and 95% confidence intervals were calculated. Results 155/215 (72%) cases and 310/429 (72%) controls consented. Pacific ethnicity, overweight and obesity, grandmultiparity, not being married, not being in paid work, social deprivation, exposure to tobacco smoke and use of recreational drugs were associated with an increased risk of late stillbirth in univariable analysis. Maternal overweight and obesity, nulliparity, grandmultiparity, not being married and not being in paid work were independently associated with late stillbirth in multivariable analysis, whereas Pacific ethnicity was no longer significant (adjusted Odds Ratio 0.99; 0.51-1.91). Conclusions Pacific ethnicity was not found to be an independent risk factor for late stillbirth in this New Zealand study. The disparity in stillbirth rates between Pacific and European women can be attributed to confounding

Toxoplasma gondii Infection and Mixed Anxiety and Depressive Disorder: A Case-Control Seroprevalence Study in Durango, Mexico

PubMed Central

Alvarado-Esquivel, Cosme; Sanchez-Anguiano, Luis Francisco; Hernandez-Tinoco, Jesus; Berumen-Segovia, Luis Omar; Torres-Prieto, Yazmin Elizabeth; Estrada-Martinez, Sergio; Perez-Alamos, Alma Rosa; Ortiz-Jurado, Maria Nalleli; Molotla-de-Leon, Gabriel; Beristain Garcia, Isabel; Rabago-Sanchez, Elizabeth; Liesenfeld, Oliver

2016-01-01

Background The parasite Toxoplasma gondii (T. gondii) may invade the brain and might induce behavioral changes. We sought to determine the association of T. gondii infection and mixed anxiety and depressive disorder. Methods Through an age- and gender-matched case-control seroprevalence study, we examined 65 patients suffering from mixed anxiety and depressive disorder (WHO ICD-10 code: F41.2) attending in a public hospital of mental health and 260 control subjects without this disorder from the general population. Sera of participants were analyzed for anti-Toxoplasma IgG and IgM antibodies using enzyme-linked immunoassays. Results Fifteen (23.1%) of the 65 patients and 18 (6.9%) of the 260 controls had anti-T. gondii IgG antibodies (odds ratio (OR): 4.03; 95% confidence interval (CI): 1.90 - 8.53; P < 0.001). The frequency of high (> 150 IU/mL) anti-T. gondii IgG levels was similar in cases and controls (OR: 0.25; 95% CI: 0.05 - 1.06; P = 0.05). Seroprevalence was similar in male cases and controls (P = 1.0); however, seroprevalence was significantly higher in female cases than in female controls (OR: 7.08; 95% CI: 2.83 - 17.67; P < 0.00001). Patients aged 31 - 50 years old had a significantly higher seroprevalence of T. gondii infection than controls of the same age group (OR: 21.04; 95% CI: 5.22 - 84.80; P < 0.00001). Anti-T. gondii IgM antibodies were found in four (26.7%) of the 15 anti-T. gondii IgG seropositive cases and in 10 (55.6%) of the 18 anti-T. gondii IgG seropositive controls (P = 0.15). Conclusions Results support for the first time an association between seropositivity to T. gondii and mixed anxiety and depressive disorder. Further research to confirm this association and to determine the seroepidemiology of T. gondii infection in patients with this disorder is needed. PMID:27298660

Phytoestrogen consumption from foods and supplements and epithelial ovarian cancer risk: a population-based case control study

PubMed Central

2011-01-01

Background While there is extensive literature evaluating the impact of phytoestrogen consumption on breast cancer risk, its role on ovarian cancer has received little attention. Methods We conducted a population-based case-control study to evaluate phytoestrogen intake from foods and supplements and epithelial ovarian cancer risk. Cases were identified in six counties in New Jersey through the New Jersey State Cancer Registry. Controls were identified by random digit dialing, CMS (Centers for Medicare and Medicaid Service) lists, and area sampling. A total of 205 cases and 390 controls were included in analyses. Unconditional logistic regression analyses were conducted to examine associations with total phytoestrogens, as well as isoflavones (daidzein, genistein, formononetin, and glycitein), lignans (matairesinol, lariciresinol, pinoresinol, secoisolariciresinol), and coumestrol. Results No statistically significant associations were found with any of the phytoestrogens under evaluation. However, there was a suggestion of an inverse association with total phytoestrogen consumption (from foods and supplements), with an odds ratio (OR) of 0.62 (95% CI: 0.38-1.00; p for trend: 0.04) for the highest vs. lowest tertile of consumption, after adjusting for reproductive covariates, age, race, education, BMI, and total energy. Further adjustment for smoking and physical activity attenuated risk estimates (OR: 0.66; 95% CI: 0.41-1.08). There was little evidence of an inverse association for isoflavones, lignans, or coumestrol. Conclusions This study provided some suggestion that phytoestrogen consumption may decrease ovarian cancer risk, although results did not reach statistical significance. PMID:21943063

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.

Case Study of the Minimum Provable Risk Considering the Variation in Background Risk: Effect of Residual Risk on Epidemiological Studies and a Comparative Assessment of Fatal Disease Risk Due to Radiation Exposure.

PubMed

Sasaki, Michiya; Ogino, Haruyuki; Hattori, Takatoshi

2018-06-08

In order to prove a small increment in a risk of concern in an epidemiological study, a large sample of a population is generally required. Since the background risk of an end point of interest, such as cancer mortality, is affected by various factors, such as lifestyle (diet, smoking, etc.), adjustment for such factors is necessary. However, it is impossible to inclusively and completely adjust for such factors; therefore, uncertainty in the background risk remains for control and exposed populations, indicating that there is a minimum limit to the lower bound for the provable risk regardless of the sample size. In this case study, we developed and discussed the minimum provable risk considering the uncertainty in background risk for hypothetical populations by referring to recent Japanese statistical information to grasp the extent of the minimum provable risk. Risk of fatal diseases due to radiation exposure, which has recently been the focus of radiological protection, was also examined by comparative assessment of the minimum provable risk for cancer and circulatory diseases. It was estimated that the minimum provable risk for circulatory disease mortality was much greater than that for cancer mortality, approximately five to seven times larger; circulatory disease mortality is more difficult to prove as a radiation risk than cancer mortality under the conditions used in this case study.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

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

Antioxidants and breast cancer risk- a population-based case-control study in Canada

PubMed Central

2011-01-01

Background The effect of antioxidants on breast cancer is still controversial. Our objective was to assess the association between antioxidants and breast cancer risk in a large population-based case-control study. Methods The study population included 2,362 cases with pathologically confirmed incident breast cancer (866 premenopausal and 1,496 postmenopausal) and 2,462 controls in Canada. Intakes of antioxidants from diet and from supplementation as well as other potential risk factors for breast cancer were collected by a self-reported questionnaire. Results Compared with subjects with no supplementation, 10 years or longer supplementation of zinc had multivariable-adjusted odds ratios (OR) and 95% confidence intervals (CI) of 0.46 (0.25-0.85) for premenopausal women, while supplementation of 10 years or longer of multiple vitamin, beta-carotene, vitamin C, vitamin E and zinc had multivariable-adjusted ORs (95% CIs) of 0.74 (0.59, 0.92), 0.58 (0.36, 0.95), 0.79 (0.63-0.99), 0.75 (0.58, 0.97), and 0.47 (0.28-0.78), respectively, for postmenopausal women. No significant effect of antioxidants from dietary sources (including beta-carotene, alpha-carotene, lycopene, lutein and zeaxanthin, vitamin C, vitamin E, selenium and zinc) or from supplementation less than 10 years was observed. Conclusions This study suggests that supplementation of zinc in premenopausal women, and supplementation of multiple vitamin, beta-carotene, vitamin C, vitamin E and zinc in postmenopausal women for 10 or more years may protect women from developing breast cancer. However, we were unable to determine the overall effect of total dose or intake from both diet and supplement. PMID:21864361

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.

Sensitivity of self-reported opioid use in case-control studies: Healthy individuals versus hospitalized patients

PubMed Central

Rashidian, Hamideh; Hadji, Maryam; Marzban, Maryam; Gholipour, Mahin; Rahimi-Movaghar, Afarin; Kamangar, Farin; Malekzadeh, Reza; Weiderpass, Elisabete; Rezaianzadeh, Abbas; Moradi, Abdolvahab; Babhadi-Ashar, Nima; Ghiasvand, Reza; Khavari-Daneshvar, Hossein; Haghdoost, Ali Akbar; Zendehdel, Kazem

2017-01-01

Background Several case-control studies have shown associations between the risk of different cancers and self-reported opium use. Inquiring into relatively sensitive issues, such as the history of drug use, is usually prone to information bias. However, in order to justify the findings of these types of studies, we have to quantify the level of such a negative bias. In current study, we aimed to evaluate sensitivity of self-reported opioid use and suggest suitable types of control groups for case-control studies on opioid use and the risk of cancer. Methods In order to compare the validity of the self-reported opioid use, we cross-validated the response of two groups of subjects 1) 178 hospitalized patients and 2) 186 healthy individuals with the results of their tests using urine rapid drug screen (URDS) and thin layer chromatography (TLC). The questioners were asked by trained interviewers to maximize the validity of responses; healthy individuals were selected from the companions of patients in hospitals. Results Self-reported regular opioid use was 36.5% in hospitalized patients 19.3% in healthy individuals (p-value> 0.001).The reported frequencies of opioid use in the past 72 hours were 21.4% and 11.8% in hospitalized patients and healthy individuals respectively. Comparing their responses with the results of urine tests showed a sensitivity of 77% and 69% among hospitalized patients and healthy individuals for self-reports (p-value = 0.4). Having corrected based on the mentioned sensitivities; the frequency of opioid regular use was 47% and 28% in hospitalized patients and healthy individuals, respectively. Regular opioid use among hospitalized patients was significantly higher than in healthy individuals (p-value> 0.001). Conclusion Our findings showed that the level of opioid use under-reporting in hospitalized patients and healthy individuals was considerable but comparable. In addition, the frequency of regular opioid use among hospitalized patients was

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.

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.

Dilatonic parallelizable NS-NS backgrounds

NASA Astrophysics Data System (ADS)

Kawano, Teruhiko; Yamaguchi, Satoshi

2003-08-01

We complete the classification of parallelizable NS-NS backgrounds in type II supergravity by adding the dilatonic case to the result of Figueroa-O'Farrill on the non-dilatonic case. We also study the supersymmetry of these parallelizable backgrounds. It is shown that all the dilatonic parallelizable backgrounds have sixteen supersymmetries.

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.

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.

Soy consumption and risk of COPD and respiratory symptoms: a case-control study in Japan

PubMed Central

Hirayama, Fumi; Lee, Andy H; Binns, Colin W; Zhao, Yun; Hiramatsu, Tetsuo; Tanikawa, Yoshimasa; Nishimura, Koichi; Taniguchi, Hiroyuki

2009-01-01

Background To investigate the relationship between soy consumption, COPD risk and the prevalence of respiratory symptoms, a case-control study was conducted in Japan. Methods A total of 278 eligible patients (244 men and 34 women), aged 50–75 years with COPD diagnosed within the past four years, were referred by respiratory physicians, while 340 controls (272 men and 68 women) were recruited from the community. All participants underwent spirometric measurements of respiratory function. Information on demographics, lifestyle characteristics and habitual food consumption was obtained using a structured questionnaire. Results Total soy consumption was positively correlated with observed lung function measures. The mean soy intake was significantly higher among controls (59.98, SD 50.23 g/day) than cases (44.84, SD 28.5 g/day). A significant reduction in COPD risk was evident for highest versus lowest quartile of daily intake of total soybean products, with adjusted odds ratio (OR) 0.392, 95% CI 0.194–0.793, p for trend 0.001. Similar decreases in COPD risk were associated with frequent and higher intake of soy foods such as tofu and bean sprouts, whereas respiratory symptoms were inversely associated with high consumption of soy foods, especially for breathlessness (OR 0.989, 95% CI 0.982–0.996). Conclusion Increasing soy consumption was associated with a decreased risk of COPD and breathlessness. PMID:19558645

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

[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.

Antibiotic use from conception to diagnosis of child leukaemia as compared to the background population: A nested case-control study.

PubMed

Gradel, Kim Oren; Kaerlev, Linda

2015-07-01

The role of infection in the aetiology of childhood leukaemia is unknown. We used prescriptions of antibiotics from Danish pharmacies as a proxy measure for the occurrence of infections. We investigated the association between exposure to antibiotics, from conception to leukaemia diagnosis, and the risk of leukaemia. Incident cases of leukaemia among children in Denmark, 1995-2008, with mothers having their earliest conception date in 1995, were individually matched to population controls by age, sex and municipality. Conditional logistic regression analyses assessed antibiotic redemptions in different time periods from conception up to 6 months before the diagnoses of all leukaemia types, acute lymphoblastic leukaemia [ALL] and ALL in 2- to 5-year-old children, adjusting for several potential confounders. A total of 120/360 (33.3%) leukaemia mothers and 1,081/3,509 (30.8%) control mothers redeemed antibiotics during pregnancy (P = 0.32). For children, the equivalent numbers were 276 (76.7%) and 2,665 (75.9%) (P = 0.76). Histograms of antibiotic redemptions showed no temporal differences between leukaemia mothers/children and controls, which was confirmed in adjusted regression analyses (OR [95% CI]: 1.02 [0.75-1.38]). Only antibiotics redeemed during the first year after birth differed from this (OR [95% CI] for ALL diagnosed in 2- to 5-year-old children: 0.46 [0.31-0.66]). In this hypothesis generating study, the similar amount and pattern of antibiotic redemptions in children with and without leukaemia indicate that infections play a minor role in the aetiology of childhood leukaemia. However, less antibiotic redemptions during the first year of life conform to Greaves' 'delayed infection hypothesis'. © 2015 Wiley Periodicals, Inc.

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.

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.

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.

A case study exploring science competence and science confidence of middle school girls from marginalized backgrounds

NASA Astrophysics Data System (ADS)

Garcia, Yeni Violeta

tools as well as ecological knowledge tools to gage change in perceptions before and after the program. Research questions centered on understanding what key components were necessary to inspire and motivate the girls to ask questions about the natural world, exploring ecological knowledge as a component of scientific literacy, and on understanding science identity formation as an integrated process. Analyses of qualitative and quantitative data occurred through a systems lens to explore the intersection of experience, identity, place, science knowledge, and science perceptions for the girls in this environment. The findings indicate that the program was successful in changing the perceptions of science the girls had at the beginning of the program compared to the end of the program. The experience was overall successful as evidenced by the experiences, stories, and insights from the eight case studies examined in depth. All case study participants indicated a continued interest in science or a newly discovered interest in science related topics that they had not considered before the program. The pre-post content test was not indicative of the concepts the girls learned through the process of scientific inquiry. These findings have implications for the design, implementation, and evaluation of current and future interventions that seek to provide opportunities for underrepresented populations, for the facilitators, classroom teachers, parents, community members, and policy makers vested in providing a space where creation, innovation, and transformation of experience can take place. This is a pivotal undertaking to inspire and prepare girls from underrepresented backgrounds to be leaders in STEM.

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

A Case-Control Study to Assess the Relationship between Poverty and Visual Impairment from Cataract in Kenya, the Philippines, and Bangladesh

PubMed Central

Kuper, Hannah; Polack, Sarah; Eusebio, Cristina; Mathenge, Wanjiku; Wadud, Zakia; Foster, Allen

2008-01-01

Background The link between poverty and health is central to the Millennium Development Goals (MDGs). Poverty can be both a cause and consequence of poor health, but there are few epidemiological studies exploring this complex relationship. The aim of this study was to examine the association between visual impairment from cataract and poverty in adults in Kenya, Bangladesh, and the Philippines. Methods and Findings A population-based case–control study was conducted in three countries during 2005–2006. Cases were persons aged 50 y or older and visually impaired due to cataract (visual acuity < 6/24 in the better eye). Controls were persons age- and sex-matched to the case participants with normal vision selected from the same cluster. Household expenditure was assessed through the collection of detailed consumption data, and asset ownership and self-rated wealth were also measured. In total, 596 cases and 535 controls were included in these analyses (Kenya 142 cases, 75 controls; Bangladesh 216 cases, 279 controls; Philippines 238 cases, 180 controls). Case participants were more likely to be in the lowest quartile of per capita expenditure (PCE) compared to controls in Kenya (odds ratio = 2.3, 95% confidence interval 0.9–5.5), Bangladesh (1.9, 1.1–3.2), and the Philippines (3.1, 1.7–5.7), and there was significant dose–response relationship across quartiles of PCE. These associations persisted after adjustment for self-rated health and social support indicators. A similar pattern was observed for the relationship between cataract visual impairment with asset ownership and self-rated wealth. There was no consistent pattern of association between PCE and level of visual impairment due to cataract, sex, or age among the three countries. Conclusions Our data show that people with visual impairment due to cataract were poorer than those with normal sight in all three low-income countries studied. The MDGs are committed to the eradication of extreme poverty

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.

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.

Factors Associated with Anti-Tuberculosis Medication Adverse Effects: A Case-Control Study in Lima, Peru

PubMed Central

Chung-Delgado, Kocfa; Revilla-Montag, Alejandro; Guillen-Bravo, Sonia; Velez-Segovia, Eduardo; Soria-Montoya, Andrea; Nuñez-Garbin, Alexandra; Silva-Caso, Wilmer; Bernabe-Ortiz, Antonio

2011-01-01

Background Long-term exposure to anti-tuberculosis medication increases risk of adverse drug reactions and toxicity. The objective of this investigation was to determine factors associated with anti-tuberculosis adverse drug reactions in Lima, Peru, with special emphasis on MDR-TB medication, HIV infection, diabetes, age and tobacco use. Methodology and Results A case-control study was performed using information from Peruvian TB Programme. A case was defined as having reported an anti-TB adverse drug reaction during 2005–2010 with appropriate notification on clinical records. Controls were defined as not having reported a side effect, receiving anti-TB therapy during the same time that the case had appeared. Crude, and age- and sex-adjusted models were calculated using odds ratios (OR) and 95% confidence intervals (95%CI). A multivariable model was created to look for independent factors associated with side effect from anti-TB therapy. A total of 720 patients (144 cases and 576 controls) were analyzed. In our multivariable model, age, especially those over 40 years (OR = 3.93; 95%CI: 1.65–9.35), overweight/obesity (OR = 2.13; 95%CI: 1.17–3.89), anemia (OR = 2.10; IC95%: 1.13–3.92), MDR-TB medication (OR = 11.1; 95%CI: 6.29–19.6), and smoking (OR = 2.00; 95%CI: 1.03–3.87) were independently associated with adverse drug reactions. Conclusions Old age, anemia, MDR-TB medication, overweight/obesity status, and smoking history are independent risk factors associated with anti-tuberculosis adverse drug reactions. Patients with these risk factors should be monitored during the anti-TB therapy. A comprehensive clinical history and additional medical exams, including hematocrit and HIV-ELISA, might be useful to identify these patients. PMID:22110689

Differences between homicide and filicide offenders; results of a nationwide register-based case-control study

PubMed Central

Putkonen, Hanna; Weizmann-Henelius, Ghitta; Lindberg, Nina; Eronen, Markku; Häkkänen, Helinä

2009-01-01

Background Filicide, the killing of one's child, is an extraordinary form of homicide. It has commonly been associated with suicide and parental psychiatric illness. In the research on filicide, nationwide studies with comparison groups, specific perpetrator subgroups, and assessment of possible risk factors have been called for. The purpose of the current study was to provide all that. Methods In this nationwide register-based case-control study all filicide offenders who were in a forensic psychiatric examination in Finland 1995–2004 were examined and compared with an age- and gender matched control group of homicide offenders. The assessed variables were psychosocial history, index offence, and psychiatric variables as well as psychopathy using the PCL-R. Results Filicide offenders were not significantly more often diagnosed with psychotic disorders than the controls but they had attempted suicide at the crime scene significantly more often. Filicide offenders had alcohol abuse/dependence and antisocial personality less often than the controls. Filicide offenders scored significantly lower on psychopathy than the controls. Within the group of filicide offenders, the psychopathy items with relatively higher scores were lack of remorse or guilt, shallow affect, callous/lack of empathy, poor behavioral controls, and failure to accept responsibility. Conclusion Since filicide offenders did not seem significantly more mentally disordered than the other homicide offenders, psychiatry alone cannot be held responsible for the prevention of filicide. Extensive international studies are needed to replicate our findings and provide more specific knowledge in order to enhance prevention. PMID:19480648

Msx1 Gene Variant - Its Presence in Tooth Absence - A Case Control Genetic Study

PubMed Central

Reddy, Naveen Admala; Adusumilli, Gopinath; Devanna, Raghu; Pichai, Saravanan; Rohra, Mayur Gobindram; Arjunan, Sharmila

2013-01-01

Background: Non Syndromic tooth agenesis is a congenital anomaly with significant medical, psychological and social ramifications. There is sufficient evidence to hypothesize that locus for this condition can be identified by candidate genes. The aim of this study was to test whether MSX1 671 T>C gene variant was involved in etiology of Non Syndromic tooth agenesis in Raichur Patients. Materials & Methods: Blood samples were collected with informed consent from 50 subjects having Non Syndromic tooth agenesis and 50 controls. Genomic DNA was extracted from the blood samples, Polymerase Chain Reaction was performed (PCR) and Restriction Fragment Length Polymorphism (RFLP) was performed for digestion products that were evaluated. Results: The Results showed positive correlation between MSX1671 T>C gene variant and Non Syndromic tooth agenesis in Raichur Patients. Conclusion: MSX1 671 T>C gene variant may be a good screening marker for Non Syndromic tooth agenesis in Raichur Patients . How to cite this article:Reddy NA, Adusumilli G, Devanna R, Pichai S, Rohra MG, Arjunan S. Msx1 Gene Variant - Its Presence in Tooth Absence - A Case Control Genetic Study. J Int Oral Health 2013; 5(5):20-6. PMID:24324300

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.

Masticatory Muscle Sleep Background EMG Activity is Elevated in Myofascial TMD Patients

PubMed Central

Raphael, Karen G.; Janal, Malvin N.; Sirois, David A.; Dubrovsky, Boris; Wigren, Pia E.; Klausner, Jack J.; Krieger, Ana C.; Lavigne, Gilles J.

2013-01-01

Despite theoretical speculation and strong clinical belief, recent research using laboratory polysomnographic (PSG) recording has provided new evidence that frequency of sleep bruxism (SB) masseter muscle events, including grinding or clenching of the teeth during sleep, is not increased for women with chronic myofascial temporomandibular disorder (TMD). The current case-control study compares a large sample of women suffering from chronic myofascial TMD (n=124) with a demographically matched control group without TMD (n=46) on sleep background electromyography (EMG) during a laboratory PSG study. Background EMG activity was measured as EMG root mean square (RMS) from the right masseter muscle after lights out. Sleep background EMG activity was defined as EMG RMS remaining after activity attributable to SB, other orofacial activity, other oromotor activity and movement artifacts were removed. Results indicated that median background EMG during these non SB-event periods was significantly higher (p<.01) for women with myofascial TMD (median=3.31 μV and mean=4.98 μV) than for control women (median=2.83 μV and mean=3.88 μV) with median activity in 72% of cases exceeding control activity. Moreover, for TMD cases, background EMG was positively associated and SB event-related EMG was negatively associated with pain intensity ratings (0–10 numerical scale) on post sleep waking. These data provide the foundation for a new focus on small, but persistent, elevations in sleep EMG activity over the course of the night as a mechanism of pain induction or maintenance. PMID:24237356

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

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.

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.

Risk Factors for Sporadic Domestically Acquired Campylobacter Infections in Norway 2010–2011: A National Prospective Case-Control Study

PubMed Central

Mexia, Ricardo; Bruun, Tone; Kapperud, Georg; Lange, Heidi; Nygård, Karin; Vold, Line

2015-01-01

Background Campylobacteriosis is the most frequently reported food- and waterborne infection in Norway. We investigated the risk factors for sporadic Campylobacter infections in Norway in order to identify areas where control and prevention measures could be improved. Methods A national prospective case-control study of factors associated with Campylobacter infection was conducted from July 2010 to September 2011. Cases were recruited from the Norwegian Surveillance System of Communicable Diseases (MSIS). Controls were randomly selected from the Norwegian Population Registry. Cases and controls were mailed a paper questionnaire with a prepaid return envelope. Univariable analyses using logistic regression were conducted for all exposures. A final parsimonious multivariable model was developed using regularized/penalized logistic regression, and adjusted odds ratios were calculated. Results A total of 995 cases and 1501 controls were included in the study (response proportion 55% and 30%, respectively). Exposures that had significant increases in odds of Campylobacter infection in multivariable analysis were drinking water directly from river, stream, or lake (OR: 2.96), drinking purchased bottled water (OR: 1.78), eating chicken (1.69), eating meat that was undercooked (OR: 1.77), eating food made on a barbecue (OR: 1.55), living on a farm with livestock (OR: 1.74), having a dog in the household (OR: 1.39), and having household water supply serving fewer than 20 houses (OR: 1.92). Conclusions Consumption of poultry and untreated water remain important sources of Campylobacter infection in Norway, despite ongoing control efforts. The results justify the need for strengthening education for consumers and food handlers about the risks of cross-contamination when preparing poultry and with consuming raw or undercooked chicken. The public should also be reminded to take precautions when drinking untreated water in nature and ensure continued vigilance in order to

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.

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.

Vitamin D status and breast cancer in Saudi Arabian women: case-control study1234

PubMed Central

Yousef, Fatimah M; Jacobs, Elizabeth T; Kang, Paul T; Hakim, Iman A; Going, Scott; Yousef, Jehad M; Al-Raddadi, Rajaa M; Kumosani, Taha A; Thomson, Cynthia A

2013-01-01

Background: The role of vitamin D in breast cancer prevention is equivocal. Saudi Arabian women may be at greater risk of vitamin D deficiency because of a darker skin type and a greater likelihood of reduced ultraviolet B radiation exposure. Data regarding the vitamin D status of Saudi Arabian women and its relation to breast cancer risk are lacking. Objective: The purpose of this research was to evaluate the association between circulating concentrations of 25-hydroxyvitamin D [25(OH)D] and breast cancer risk in Saudi Arabian women. Design: A case-control study was conducted among 120 breast cancer cases and 120 controls. The study population was drawn from patients admitted to King Fahd Hospital in Jeddah, Saudi Arabia, from June to August 2009. Participants completed questionnaires on diet and medical history, and serum samples were collected from all women to measure circulating 25(OH)D concentrations. Results: The participants had a mean age of 47.8 y and a mean body mass index (BMI; in kg/m2) of 30.0. Breast cancer cases had significantly lower (mean ± SD) serum concentrations of 25(OH)D (9.4 ± 6.4 ng/mL) than did controls (15.4 ± 12.3 ng/mL; P = 0.001). In comparison with those in the highest category of vitamin D status for this population (≥20 ng/mL), the adjusted ORs (95% CIs) for invasive breast cancer were 6.1 (2.4, 15.1) for women with a serum 25(OH)D concentration <10 ng/mL and 4.0 (1.6, 10.4) for women with a serum concentration of ≥10 to <20 ng/mL (P-trend = 0.0001). Conclusion: An inverse association exists between serum 25(OH)D concentrations and breast cancer risk in Saudi Arabian women. This trial was registered at clinicaltrials.gov as NCT01817231. PMID:23697705

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.

Self-perceived psychological stress and ischemic stroke: a case-control study

PubMed Central

Jood, Katarina; Redfors, Petra; Rosengren, Annika; Blomstrand, Christian; Jern, Christina

2009-01-01

Background A growing body of evidence suggests that psychological stress contributes to coronary artery disease. However, associations between stress and stroke are less clear. In this study, we investigated the possible association between ischemic stroke and self-perceived psychological stress, as measured by a single-item questionnaire, previously reported to be associated with myocardial infarction. Methods In the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS), 600 consecutive patients with acute ischemic stroke (aged 18 to 69 years) and 600 age-matched and sex-matched population controls were recruited. Ischemic stroke subtype was determined according to Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. Self-perceived psychological stress preceding stroke was assessed retrospectively using a single-item questionnaire. Results Permanent self-perceived psychological stress during the last year or longer was independently associated with overall ischemic stroke (multivariate adjusted odds ratio (OR) 3.49, 95% confidence interval (CI) 2.06 to 5.93). Analyses by stroke subtype showed that this association was present for large vessel disease (OR 3.91, 95% CI 1.58 to 9.67), small vessel disease (OR 3.20, 95% CI 1.64 to 6.24), and cryptogenic stroke (OR 4.03, 95% CI 2.34 to 6.95), but not for cardioembolic stroke (OR 1.48, 95% CI 0.64 to 3.39). Conclusion In this case-control study, we found an independent association between self-perceived psychological stress and ischemic stroke. A novel finding was that this association differed by ischemic stroke subtype. Our results emphasize the need for further prospective studies addressing the potential role for psychological stress as a risk factor for ischemic stroke. In such studies ischemic stroke subtypes should be taken into consideration. PMID:19796376

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.

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.

Uncovering clinical and radiological associations of triphasic waves in acute encephalopathy: a case-control study.

PubMed

Sutter, R; Kaplan, P W

2014-04-01

Triphasic waves (TWs) are archetypal waveforms seen on electroencephalography (EEG) in some forms of encephalopathy. Their particular underlying pathological substrates are largely unexplored. This case-control study was designed to identify and quantify specific clinical and neuroradiological associations underlying TWs and to determine if TWs predicate outcome. From 2004 to 2012, adult encephalopathic patients with TWs (cases) were matched 1:1 with encephalopathic patients without TWs (controls) by Glasgow Coma Scale (GCS) and the frequency range of EEG background activity. Clinical characteristics, neuroimaging and outcomes were assessed. The mean age of 190 patients (95 with and 95 without TWs) was 66.6 years (±15.6). In multivariable analyses, patients with TWs had significantly higher odds for liver insufficiency [odds ratio (OR) = 8.10, 95% confidence interval (CI) 1.98-33.08], alcohol abuse (OR = 3.65, 95% CI 1.25-10.63), subcortical brain atrophy (OR = 2.82, 95% CI 1.39-5.71) and respiratory tract infections (OR = 1.28, 95% CI 1.01-4.71). With each additional independent predictor, the odds increased for the occurrence of TWs (1 predictor, OR = 2.40, 95% CI 1.16-5.13; ≥2 predictors, OR = 9.20, 95% CI 3.27-25.62). Mortality was 15% and tended to be higher in patients with TWs (19% with vs. 11% without TWs). Alcohol abuse, liver insufficiency, infections and subcortical brain atrophy were independently associated with TWs in patients matched for clinical and EEG features of encephalopathy. These associations strengthen the hypothesis that TWs evolve from an interplay of pathological neurostructural, metabolic and toxic conditions. When matched for EEG background activity and GCS, TWs were not associated with death. © 2014 The Author(s) European Journal of Neurology © 2014 EFNS.

Bio-Inspired Bright Structurally Colored Colloidal Amorphous Array Enhanced by Controlling Thickness and Black Background.

PubMed

Iwata, Masanori; Teshima, Midori; Seki, Takahiro; Yoshioka, Shinya; Takeoka, Yukikazu

2017-07-01

Inspired by Steller's jay, which displays angle-independent structural colors, angle-independent structurally colored materials are created, which are composed of amorphous arrays of submicrometer-sized fine spherical silica colloidal particles. When the colloidal amorphous arrays are thick, they do not appear colorful but almost white. However, the saturation of the structural color can be increased by (i) appropriately controlling the thickness of the array and (ii) placing the black background substrate. This is similar in the case of the blue feather of Steller's jay. Based on the knowledge gained through the biomimicry of structural colored materials, colloidal amorphous arrays on the surface of a black particle as the core particle are also prepared as colorful photonic pigments. Moreover, a structural color on-off system is successfully built by controlling the background brightness of the colloidal amorphous arrays. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Association Between Hepatocellular Carcinoma and Type 2 Diabetes Mellitus in Chinese Hepatitis B Virus Cirrhosis Patients: A Case-Control Study

PubMed Central

Han, Huixian; Deng, Han; Han, Tao; Zhao, Haitao; Hou, Feifei; Qi, Xingshun

2017-01-01

Background Whether the presence of type 2 diabetes mellitus (T2DM) increases the risk of hepatocellular carcinoma (HCC) in hepatitis B virus (HBV) cirrhosis patients is controversial. We conducted a retrospective case-control study to evaluate this issue. Material/Methods We considered all patients diagnosed with HBV-related liver cirrhosis at our hospital from July 2011 to June 2014. The case (n=91) and control (n=91) groups were HBV cirrhosis patients with and without T2DM, respectively. They were matched at a ratio of 1: 1 according to the individual age (±2 years) and same sex and Child-Pugh score. Results None of the baseline data were significantly different between the 2 groups. The percentage of HCC was similar between the 2 groups (case versus control group: 34.1% versus 46.2%, P=0.13). In the case group, sex (P=0.002), alkaline phosphatase (P<0.001), γ-glutamine transferase (P=0.001), and sodium (P=0.003) were associated with the risk of HCC. In the control group, platelet (P=0.041), alanine aminotransferase (P=0.034), aspartate aminotransferase (P=0.026), alkaline phosphatase (P<0.001), and γ-glutamine transferase (P<0.001) were associated with the risk of HCC. Conclusions T2DM may not be a risk factor for the presence of HCC in HBV cirrhosis. PMID:28689209

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

Household air pollution, chronic respiratory disease and pneumonia in Malawian adults: A case-control study.

PubMed

Jary, Hannah R; Aston, Stephen; Ho, Antonia; Giorgi, Emanuele; Kalata, Newton; Nyirenda, Mulinda; Mallewa, Jane; Peterson, Ingrid; Gordon, Stephen B; Mortimer, Kevin

2017-01-01

Background: Four million people die each year from diseases caused by exposure to household air pollution. There is an association between exposure to household air pollution and pneumonia in children (half a million attributable deaths a year); however, whether this is true in adults is unknown. We conducted a case-control study in urban Malawi to examine the association between exposure to household air pollution and pneumonia in adults. Methods: Hospitalized patients with radiologically confirmed pneumonia (cases) and healthy community controls underwent 48 hours of ambulatory and household particulate matter (µg/m 3 ) and carbon monoxide (ppm) exposure monitoring. Multivariate logistic regression, stratified by HIV status, explored associations between these and other potential risk factors with pneumonia. Results: 145 (117 HIV-positive; 28 HIV-negative) cases and 253 (169 HIV-positive; 84 HIV-negative) controls completed follow up. We found no evidence of association between household air pollution exposure and pneumonia in HIV-positive (e.g. ambulatory particulate matter adjusted odds ratio [aOR] 1.00 [95% CI 1.00-1.01, p=0.141]) or HIV-negative (e.g. ambulatory particulate matter aOR 1.00 [95% CI 0.99-1.01, p=0.872]) participants. Chronic respiratory disease was associated with pneumonia in both HIV-positive (aOR 28.07 [95% CI 9.29-84.83, p<0.001]) and HIV-negative (aOR 104.27 [95% CI 12.86-852.35, p<0.001]) participants. Conclusions: We found no evidence that exposure to household air pollution is associated with pneumonia in Malawian adults. In contrast, chronic respiratory disease was strongly associated with pneumonia.

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.

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.

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.

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.

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.

The Relevance of Maternal Socioeconomic Characteristics for Low Birth Weight - a Case-Control Study.

PubMed

Altenhöner, T; Köhler, M; Philippi, M

2016-03-01

Introduction: The number of children born underweight (low birth weight, LBW) is increasing despite extensive prevention and screening programmes. The cost is high for the health system, and affected children are burdened with health predictors that can affect them negatively throughout their lives. This study investigates to what extent socioeconomic factors, in addition to known medical causes and the health behaviour of pregnant women, influence LBW. Materials and Methods: In this case-control study 131 mothers of singletons with a birth weight ≤ 2500 g (cases) and 323 mothers of normal birth weight babies (controls) were interviewed with respect to socioeconomic status, health behaviour and stress in the workplace. Medical data were collected by specialist staff using a questionnaire. Results: Independent of medical diagnosis and health behaviour, women with lower level education (OR [95 % CI] = 2.24 [1.12; 4.51]) and those who were not working (OR [95 % CI] = 1.82 [1.10; 3.00]) were more likely to have an LBW baby. No effect was shown for immigrant background (OR [95 % CI] = 1.14 [0.59; 2.21]) or stress in the workplace (OR [95 % CI] = 1.17 [0.90; 1.51]). Discussion and Conclusion: These results show that the association between social and health inequalities starts from before birth. In order to reduce the rising number of babies born underweight, socioeconomic determinants in the care and supervision of pregnant women should systematically receive more attention to enable appropriate early preventive strategies to be implemented.

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 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.

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.

Analysis of new lactotransferrin gene variants in a case-control study related to periodontal disease in dog.

PubMed

Morinha, Francisco; Albuquerque, Carlos; Requicha, João; Dias, Isabel; Leitão, José; Gut, Ivo; Guedes-Pinto, Henrique; Viegas, Carlos; Bastos, Estela

2012-04-01

The molecular and genetic research has contributed to a better understanding of the periodontal disease (PD) in humans and has shown that many genes play a role in the predisposition and progression of this complex disease. Variations in human lactotransferrin (LTF) gene appear to affect anti-microbial functions of this molecule, influencing the PD susceptibility. PD is also a major health problem in small animal practice, being the most common inflammatory disease found in dogs. Nevertheless, the research in genetic predisposition to PD is an unexplored subject in this species. This work aims to contribute to the characterization of the genetic basis of canine PD. In order to identify genetic variations and verify its association with PD, was performed a molecular analysis of LTF gene in a case-control approach, including 40 dogs in the PD cases group and 50 dogs in the control group. In this study were detected and characterized eight new single nucleotide variations in the dog LTF gene. Genotype and allele frequencies of these variations showed no statistically significant differences between the control and PD cases groups. Our data do not give evidence for the contribution of these LTF variations to the genetic background of canine PD. Nevertheless, the sequence variant L/15_g.411C > T leads to an aminoacid change (Proline to Leucine) and was predicted to be possibly damaging to the LTF protein. Further investigations would be of extreme value to clarify the biological importance of these new findings.

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.

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.

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.

Choline and Betaine Intake and Colorectal Cancer Risk in Chinese Population: A Case-Control Study

PubMed Central

Pan, Zhi-Zhong; Zhong, Xiao; Zheng, Mei-Chun; Chen, Yu-Ming; Zhang, Cai-Xia

2015-01-01

Background Few studies have examined the association of choline and betaine intake with colorectal cancer risk, although they might play an important role in colorectal cancer development because of their role as methyl donors. The aim of this study was to examine the relationship between consumption of choline and betaine and colorectal cancer risk in a Chinese population. Methodology/Principal Findings A case-control study was conducted between July 2010 and December 2013 in Guangzhou, China. Eight hundred and ninety consecutively recruited colorectal cancer cases were frequency matched to 890 controls by age (5-year interval) and sex. Dietary information was assessed with a validated food frequency questionnaire by face-to-face interviews. The logistic regression model was used to estimate multivariate odds ratios (ORs) and 95% confidence intervals (CIs). Total choline intake was inversely associated with colorectal cancer risk after adjustment for various lifestyle and dietary factors. The multivariate-adjusted OR was 0.54 (95%CI = 0.37-0.80, Ptrend <0.01) comparing the highest with the lowest quartile. No significant associations were observed for betaine or total choline+betaine intakes. For choline-containing compounds, lower colorectal cancer risk was associated with higher intakes of choline from phosphatidylcholine, glycerophosphocholine and sphingomyelin but not for free choline and phosphocholine. The inverse association of total choline intake with colorectal cancer risk was observed in both men and women, colon and rectal cancer. These inverse associations were not modified by folate intake. Conclusions These results indicate that high intake of total choline is associated with a lower risk of colorectal cancer. PMID:25785727

[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.

HIV and Childhood Disability: A Case-Controlled Study at a Paediatric Antiretroviral Therapy Centre in Lilongwe, Malawi

PubMed Central

Devendra, Akash; Makawa, Atupele; Kazembe, Peter N.; Calles, Nancy R.; Kuper, Hannah

2013-01-01

Background As paediatric antiretroviral therapy (ART) is rapidly scaled up in Southern Africa, Human Immunodeficiency Virus (HIV) infection is becoming a chronic illness. Children growing up with HIV may begin to encounter disabilities. The relationship between HIV, disability and the need for rehabilitation has added an additional element that needs to be addressed by paediatric HIV treatment programmes. Study Objectives 1) Estimate the prevalence of disabilities in HIV-infected and HIV-uninfected children in Lilongwe, Malawi. 2) Examine types of disability and associated clinical and socio-demographic factors. 3) Identify needs, opportunities and barriers for rehabilitation in Malawi. Methods A case-controlled study of 296 HIV-infected children aged 2–9 years attending an ART centre in Lilongwe (cases) and their uninfected siblings (controls) was conducted. Disability was assessed using the WHO Ten Question Screen (TQS). Socio-demographic and clinical data were collected using a parent-proxy questionnaire and medical records. Results Of 296 case and control pairs recruited, 33% (98) versus 7% (20) screened positive for a disability (OR 8.4, 4.4–15.7) respectively. Of these 98 HIV-infected cases, 6%, 36%, 33%, 53%, 46% and 6% had a vision, hearing; physical, learning/comprehension, speech or seizure-related disability respectively and 51% had multiple coexisting disabilities. HIV-infected cases with a disability were more likely to be WHO stage III or IV at enrolment (71% vs. 52%, OR 2.7, 1.5–4.2), to have had TB (58% vs. 39%, OR 2.3, 1.4–3.8) and to have below-average school grades (18% vs. 2%, OR 11.1, 2.2–54.6) than those without. Sixty-seven percent of cases with a disability had never attended any rehabilitative service. Twenty-nine percent of caregivers reported facing stigma and discrimination because of the child’s disability. Conclusion This study reveals the magnitude of disability among HIV-infected children and the large unmet need for

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.

Acrylamide Hemoglobin Adduct Levels and Ovarian Cancer Risk: a nested case-control study

PubMed Central

Xie, Jing; Terry, Kathryn L.; Poole, Elizabeth M.; Wilson, Kathryn M.; Rosner, Bernard A.; Willett, Walter C.; Vesper, Hubert W.; Tworoger, Shelley S.

2013-01-01

Background Acrylamide is a probable human carcinogen formed during cooking of starchy foods. Two large prospective cohort studies of dietary acrylamide intake and ovarian cancer risk observed a positive association, although two other studies reported no association. Methods We measured acrylamide exposure using red blood cell acrylamide and glycidamide hemoglobin adducts among women in two large prospective cohorts: the Nurses’ Health Study and Nurses’ Health Study II. Between blood collection and 2010, we identified 263 incident cases of epithelial ovarian cancer, matching two controls per case. We used logistic regression models to examine the association between acrylamide exposure and ovarian cancer risk, adjusting for matching factors, family history of ovarian cancer, tubal ligation, oral contraceptive use, body mass index (BMI), parity, alcohol intake, smoking, physical activity, and caffeine intake. Results The multivariate-adjusted relative risk (RR) of ovarian cancer comparing the highest versus lowest tertile of total acrylamide adducts was 0.79 (95% CI: 0.50–1.24, P trend = 0.08). The comparable RR of ovarian cancer among non-smokers at blood draw was 0.85 (95% CI: 0.57–1.27, P trend =0.14). The association did not differ by tumor histology (serous invasive versus not), P for heterogeneity=0.41. Individual adduct types (acrylamide or glycidamide) were not associated with risk. Conclusions We observed no evidence that acrylamide exposure as measured by adducts to hemoglobin is associated with an increased risk of ovarian cancer. Impact Our finding indicates that acrylamide intake may not increase risk of ovarian cancer. PMID:23417989

Prevalence of Small Intestinal Bacterial Overgrowth among Chronic Pancreatitis Patients: A Case-Control Study

PubMed Central

Bouchard, Simon; Sidani, Sacha

2016-01-01

Background. Patients with chronic pancreatitis (CP) exhibit numerous risk factors for the development of small intestinal bacterial overgrowth (SIBO). Objective. To determine the prevalence of SIBO in patients with CP. Methods. Prospective, single-centre case-control study conducted between January and September 2013. Inclusion criteria were age 18 to 75 years and clinical and radiological diagnosis of CP. Exclusion criteria included history of gastric, pancreatic, or intestinal surgery or significant clinical gastroparesis. SIBO was detected using a standard lactulose breath test (LBT). A healthy control group also underwent LBT. Results. Thirty-one patients and 40 controls were included. The patient group was significantly older (53.8 versus 38.7 years; P < 0.01). The proportion of positive LBTs was significantly higher in CP patients (38.7 versus 2.5%: P < 0.01). A trend toward a higher proportion of positive LBTs in women compared with men was observed (66.6 versus 27.3%; P = 0.056). The subgroups with positive and negative LBTs were comparable in demographic and clinical characteristics, use of opiates, pancreatic enzymes replacement therapy (PERT), and severity of symptoms. Conclusion. The prevalence of SIBO detected using LBT was high among patients with CP. There was no association between clinical features and the risk for SIBO. PMID:27446865

Prevalence of Small Intestinal Bacterial Overgrowth among Chronic Pancreatitis Patients: A Case-Control Study.

PubMed

Therrien, Amelie; Bouchard, Simon; Sidani, Sacha; Bouin, Mickael

2016-01-01

Background. Patients with chronic pancreatitis (CP) exhibit numerous risk factors for the development of small intestinal bacterial overgrowth (SIBO). Objective. To determine the prevalence of SIBO in patients with CP. Methods. Prospective, single-centre case-control study conducted between January and September 2013. Inclusion criteria were age 18 to 75 years and clinical and radiological diagnosis of CP. Exclusion criteria included history of gastric, pancreatic, or intestinal surgery or significant clinical gastroparesis. SIBO was detected using a standard lactulose breath test (LBT). A healthy control group also underwent LBT. Results. Thirty-one patients and 40 controls were included. The patient group was significantly older (53.8 versus 38.7 years; P < 0.01). The proportion of positive LBTs was significantly higher in CP patients (38.7 versus 2.5%: P < 0.01). A trend toward a higher proportion of positive LBTs in women compared with men was observed (66.6 versus 27.3%; P = 0.056). The subgroups with positive and negative LBTs were comparable in demographic and clinical characteristics, use of opiates, pancreatic enzymes replacement therapy (PERT), and severity of symptoms. Conclusion. The prevalence of SIBO detected using LBT was high among patients with CP. There was no association between clinical features and the risk for SIBO.

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.

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.

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

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

Macronutrients, vitamins and minerals intake and risk of esophageal squamous cell carcinoma: a case-control study in Iran

PubMed Central

2011-01-01

Background Although Iran is a high-risk region for esophageal squamous cell carcinoma (ESCC), dietary factors that may contribute to this high incidence have not been thoroughly studied. The aim of this study was to evaluate the effect of macronutrients, vitamins and minerals on the risk of ESCC. Methods In this hospital-based case-control study, 47 cases with incident ESCC and 96 controls were interviewed and usual dietary intakes were collected using a validated food frequency questionnaire. Data were modeled through unconditional multiple logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI), controlling for age, sex, gastrointestinal reflux, body mass index, smoking history (status, intensity and duration), physical activity, and education. Results ESCC cases consumed significantly more hot foods and beverages and fried and barbecued meals, compared to the controls (p < 0.05). After adjusting for potential confounders, the risk of ESCC increased significantly in the highest tertiles of saturated fat [OR:2.88,95%CI:1.15-3.08], cholesterol [OR:1.53, 95%CI: 1.41-4.13], discretionary calorie [OR:1.51, 95%CI: 1.06-3.84], sodium [OR:1.49,95%CI:1.12-2.89] and total fat intakes [OR:1.48, 95%CI:1.09-3.04]. In contrast, being in the highest tertile of carbohydrate, dietary fiber and (n-3) fatty acid intake reduced the ESCC risk by 78%, 71% and 68%, respectively. The most cancer-protective effect was observed for the combination of high folate and vitamin E intakes (OR: 0.02, 95%CI: 0.00-0.87; p < 0.001). Controls consumed 623.5 times higher selenium, 5.48 times as much β-carotene and 1.98 times as much α-tocopherol as the amount ESCC cases consumed. Conclusion This study suggests that high intake of nutrients primarily found in plant-based foods is associated with a reduced esophageal cancer risk. Some nutrients such as folate, vitamin E and selenium might play major roles in the etiology of ESCC and their status may eventually be used as

Inhalation Toxicity of Humidifier Disinfectants as a Risk Factor of Children’s Interstitial Lung Disease in Korea: A Case-Control Study

PubMed Central

Yu, Jinho; Lee, Eun; Jung, Young-Ho; Kim, Hyung-Young; Seo, Ju-Hee; Kwon, Geun-Yong; Park, Ji-Hyuk; Gwack, Jin; Youn, Seung-Ki; Kwon, Jun-Wook; Jun, Byung-Yool; Kim, Kyung Won; Ahn, Kangmo; Lee, Soo-Young; Park, June-Dong; Kwon, Ji-Won; Kim, Byoung-Ju; Lee, Moo-Song; Do, Kyung-Hyun; Jang, Se-Jin; Pyun, Bok-Yang; Hong, Soo-Jong

2013-01-01

Background The occurrence of numerous cases of interstitial lung disease in children (chILD) every spring in Korea starting in 2006 raised suspicion about a causal relationship with the use of humidifier disinfectants (HDs). The aim of this study was to evaluate the association between HD use and the risk of chILD. Methods This retrospective, 1∶3 matched case-control study consisted of 16 cases of chILD that had developed between 2010 and 2011. The three groups of parallel controls (patients with acute lobar pneumonia, asthma, and healthy children) were matched by age, gender, and index date. Indoor/outdoor environmental risk factors, including HD use, were investigated by asking the guardians to complete a questionnaire. Results The median age of the affected children (43.8% male) was 26 months (18.25–36.25). The chILD group did not differ significantly from the control groups with respect to socio-demographic and clinical variables. Indoor and outdoor environmental factors were not associated with a risk of chILD. However, the previous use of HDs (OR; 2.73. 95% CI; 1.41–5.90, P = 0.00) were independently associated with an increased risk. Conclusions This study showed that HDs, which are widely used in South Korea in the winter season, independently increased the risk of chILD in spring. Therefore, continuous monitoring and, if needed, changes in policy are essential to prevent and control pediatric diseases caused by toxic chemicals. PMID:23755124

A Nested Case-Control Study of Intrauterine Exposure to Persistent Organochlorine Pollutants and the Risk of Hypospadias

PubMed Central

Rignell-Hydbom, Anna; Lindh, Christian H.; Dillner, Joakim; Jönsson, Bo A. G.; Rylander, Lars

2012-01-01

Background Environmental exposures to endocrine disrupting chemicals have been suggested as a risk factor for male genital abnormalities such as hypospadias. The aim of this case-control study was to investigate the association between fetal exposure to persistent organochlorine pollutants (POP) and the risk for hypospadias. Methodology/Principal Findings The Southern Sweden Maternity Cohort (SSMC) contains serum samples collected in early pregnancy among women in Southern Sweden. Linkages with the Medical Birth Register, the Malformation Register and the In-patient Register resulted in 390 SSMC mothers who had given birth to a boy with hypospadias in year 1986–2002 (mean 1995). For 237 of these (cases) sufficient amounts of serum for the chemical analyses were available. For each case, a control boy from the SSMC was randomly selected, matched for maternal age, birth year, parity and maternal smoking. PCB-153, p,p’-DDE and hexachlorbenzene (HCB) were used as biomarkers for POP exposure. The exposures were categorized into quartiles based on the distributions among the controls. There were no statistically significant trends between the a priori categorisation of the exposure variables and the risk for hypospadias. However, when the upper HCB quartile (>26 ng/ml) was compared to the other quartiles an odds ratio of 1.65 (95% CI 1.02 to 2.69) was obtained. p,p′-DDE levels above median (>1.0 ng/ml) compared to levels below 0.1 ng/ml gave an OR of 1.69 (95% CI 0.97 to 2.93). Conclusions The present study suggests that fetal exposure to HCB and p,p’-DDE may be a risk factor for hypospadias. PMID:23028613

Pregnancy-related maternal risk factors of attention-deficit hyperactivity disorder: a case-control study.

PubMed

Amiri, Shahrokh; Malek, Ayyoub; Sadegfard, Majid; Abdi, Salman

2012-01-01

Background. The etiology of attention-deficit hyperactivity disorder (ADHD) is complex.This study was conducted to evaluate the pregnancy-related maternal risk factors of ADHD. Methods. 164 ADHD children attending to Child and Adolescent Psychiatric Clinics compared with 166 normal children selected in a random-cluster method from primary schools. ADHD rating scale and clinical interview based on Schedule for Affective disorders and Schizophrenia for School-Aged Children (K-SADS) were used to diagnose ADHD cases and to select the control group. Results. The mean maternal age at pregnancy, duration of pregnancy, and the mean paternal age were alike in two groups. The ADHD children's mothers compared with those of control group had higher frequencies of somatic diseases, psychiatric disorders, and alcohol and cigarette exposure during the pregnancies (P < 0.01). Also birth by cesarean section was more common among mothers of ADHD children (P < 0.001). These factors plus trauma to the abdomen during pregnancy were significantly predictors of ADHD in children. Conclusions. Some pregnancy-related maternal factors may be considered as environmental risk factors for ADHD. Each of these factors considered in our study as a risk factor needs to be tested and confirmed through next methodologically appropriate researches in this field.

Case-control study of birth characteristics and the risk of hepatoblastoma

PubMed Central

Heck, Julia E; Meyers, Travis J; Lombardi, Christina; Park, Andrew S; Cockburn, Myles; Reynolds, Peggy; Ritz, Beate

2013-01-01

Background Hepatoblastoma is a malignant embryonal tumor typically diagnosed in children younger than five years of age. Little is known on hepatoblastoma etiology. Methods We matched California Cancer Registry records of hepatoblastomas diagnosed in children younger than age 6 from 1988–2007 to birth records using a probabilistic record linkage program, yielding 261 cases. Controls (n=218,277), frequency matched by birth year to all cancer cases in California for the same time period, were randomly selected from California birth records. We examined demographic and socioeconomic information, birth characteristics, pregnancy history, complications in pregnancy, labor and delivery, and abnormal conditions and clinical procedures relating to the newborn, with study data taken from birth certificates. Results We observed increased risks for hepatoblastoma among children with low [1500–2499 g, Odds Ratio (OR)=2.02, 95% confidence interval (CI) 1.29–3.15] and very low birthweight (<1500 g, OR=15.4, 95% CI 10.7–22.3), preterm birth <33 weeks (OR=7.27, 95% CI 5.00, 10.6), small size for gestational age (OR=1.75, 95% CI 1.25–2.45), and with multiple birth pregnancies (OR=2.52, 95% CI 1.54–4.14). We observed a number of pregnancy and labor complications to be related to hepatoblastoma, including preeclampsia, premature labor, fetal distress, and congenital anomalies. Conclusions These findings confirm previously reported associations with low birthweight and preeclampsia. The relation with multiple birth pregnancies has been previously reported and may indicate a relation to infertility treatments. PMID:23558166

Effect of vitamin C supplementation on stroke recovery: A case-control study

PubMed Central

Rabadi, Meheroz H; Kristal, Bruce S

2007-01-01

Background and purpose: Epidemiological studies have associated increased dietary intake of antioxidants (vitamin C, E, and β-carotene) in preventing and decreasing the extent of ischemic brain injury. The effect of vitamin C supplementation on functional recovery after stroke has not been studied. Method: In this retrospective, case-control study of 23 patients with ischemic stroke taking vitamin C were identified and matched for age, sex, onset to admission, and admission total functional independence measure (TFIM) with 23 patients with ischemic stroke not taking Vitamin C supplementation. Vitamin C 1000 mg daily was prescribed on admission to our unit mainly to patients who were undernourished (defined as significant weight loss and/or 90% or less ideal body weight for age and sex) and those with pressure sores. The outcome measures were: change in the TFIM, FIM-Cognition (FIM-Cog), and FIM-Motor sub-scores, discharge disposition, and length of stay (LOS). Results: The change in TFIM (20 ± 13 standard deviation [SD] vs. 26 ± 6, p = 0.20), FIM-Cog (3 ± 3 SD vs. 4 ± 5, p = 0.41), FIM-Motor (15 ± 11 SD vs. 20 ± 13, p = 0.21) sub-scores were less in the vitamin C treated group, but these differences did not reach statistical significance. Similarly, no significant differences were found in LOS (21 ± 9 SD vs. 23 ± 9, p = 0.59), and discharge disposition (home/institution) (9/10 vs. 13/9, p = 0.60) between the vitamin C and the control groups. Conclusion: This study suggests vitamin C supplementation did not enhance functional recovery in undernourished ischemic stroke patients. PMID:18044087

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

Fast Foods, Sweets and Beverage Consumption and Risk of Colorectal Cancer: A Case-Control Study in Jordan

PubMed Central

Tayyem, Reema F; Bawadi, Hiba A; Shehadah, Ihab; Bani-Hani, Kamal E; Takruri, Hamed; Al-Jaberi, Tareq; Heath, Dennis D

2018-01-01

Background: The effects of consuming fast foods, sweets and beverages on the development of colorectal cancer (CRC) are unclear. The aim of this case-control study was to assess possible associations between the consumption of different fast foods, sweets and beverages and CRC risk in a Jordanian population. Methods: Two hundred and twenty diagnosed CRC cases and 281 controls were enrolled. Diet history was obtained using a validated quantitative questionnaire. Results: Consumption of some types of fast food, and particularly falafel, was associated with an increased risk of developing CRC. Elevated risk was found for potato and corn chips with an AOR of 4.36 (95%CI: 1.24-15.28) for daily consumption and 3.33 (95%CI: 1.00-11.11) for ≥5 servings/week. Consuming 1-2 or >5 servings per week of fried potatoes or 2-3 servings per week of chicken in sandwiches also increased the risk while exposure to fresh tomato juice and hot pepper sauce on a monthly basis appeared to exert a protective effect. Conclusions: Consumption of fried fast food items was significantly linked with an increased risk of developing CRC in Jordan. PMID:29374411

Pleural mesothelioma and occupational and non-occupational asbestos exposure: a case-control study with quantitative risk assessment.

PubMed

Ferrante, Daniela; Mirabelli, Dario; Tunesi, Sara; Terracini, Benedetto; Magnani, Corrado

2016-03-01

Casale Monferrato (north west Italy) is an area with an exceptionally high incidence of mesothelioma caused by asbestos contamination at work and in the general environment from the asbestos-cement Eternit plant that was operational until 1986. The purpose of this study was to quantify the association between pleural malignant mesothelioma (PMM) and asbestos cumulative exposure using individual assessment of environmental and domestic exposure, as well as of occupational exposure. This population-based case-control study included cases of PMM diagnosed between January 2001 and June 2006 among residents in the Casale Monferrato Local Health Authority. Population controls were randomly sampled, matched by age and sex to cases. Cumulative exposure was estimated to account for the lifelong exposure history. Analyses were conducted using unconditional logistic regression models adjusting for gender, age at diagnosis and type of interview (direct or proxy respondents). 200 PMM cases of 223 eligible cases (89.7%) and 348 (63%) of 552 eligible controls accepted to be interviewed. ORs increased with cumulative exposure index (p<0.0001) from 4.4 (CI 95% 1.7 to 11.3) (<1 f/mL-years) to 62.1 (CI 95% 22.2 to 173.2) (≥10 f/mL-years). Among subjects never occupationally exposed, corresponding ORs were 3.8 (CI 95% 1.3 to 11.1) and 23.3 (CI 95% 2.9 to 186.9) (reference: background level of asbestos exposure). ORs of about 2, statistically significant, were observed for domestic exposure and for living in houses near buildings with large asbestos cement parts. Risk of PMM increased with cumulative asbestos exposure and also in analyses limited to subjects non-occupationally exposed. Our results also provide indication of risk associated with common sources of environmental exposure and are highly relevant for the evaluation of residual risk after the cessation of asbestos industrial use. Published by the BMJ Publishing Group Limited. For permission to use (where not already

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.

Association of rs1344706 in the ZNF804A gene with schizophrenia in a case/control sample from Indonesia.

PubMed

Schwab, Sibylle G; Kusumawardhani, Agung A A A; Dai, Nan; Qin, WenWen; Wildenauer, Mutiara D B; Agiananda, Feranindhya; Amir, Nurmiati; Antoni, Ronald; Arsianti, Tiana; Asmarahadi, Asmarahadi; Diatri, Hervita; Djatmiko, Prianto; Irmansyah, Irmansyah; Khalimah, Siti; Kusumadewi, Irmia; Kusumaningrum, Profitasari; Lukman, Petrin R; Mustar, Lukman; Nasrun, Martina W; Naswati, Safyuni; Prasetiyawan, Prasetiyawan; Semen, Gerald M; Siste, Kristiana; Tobing, Heriani; Widiasih, Natalia; Wiguna, Tjhin; Wulandari, Widayanti Dewi; Benyamin, Beben; Wildenauer, Dieter B

2013-06-01

Association of rs1344706 in the ZNF804A gene (2q32.1) with schizophrenia was first reported in a genome wide scan conducted in a sample of 479 cases and replicated in 6666 cases. Subsequently, evidence by replication was obtained in several samples with European- and Asian ancestral background. We report ascertainment, clinical characterization, quality control, and determination of ancestral background of a case control sample from Indonesia, comprising 1067 cases and 1111 ancestry matched controls. Genotyping was performed using a fluorescence-based allelic discrimination assay (TaqMan SNP genotyping assay) and a newly designed PCR-RFLP assay for confirmation of rs1344706 genotypes. We confirmed association of the T-allele of rs1344706 with schizophrenia in a newly ascertained sample from Indonesia with Southeast Asian ancestral background (P=0.019, OR=1.155, 95%, CI 1.025-1.301). In addition, we studied several SNPs in the vicinity of rs1344706, for which nominally significant results had been reported. None of the association P values of the additional SNPs exceeded that of rs1344706. We provide additional evidence for association of the ZNF804A gene with schizophrenia. We conclude that rs1344706 or a yet unknown polymorphism in linkage disequilibrium is also involved in conferring susceptibility to schizophrenia in samples with different (Asian) ancestral backgrounds. Copyright © 2013 Elsevier B.V. All rights reserved.

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.

Modeling background radiation using geochemical data: A case study in and around Cameron, Arizona

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

Marsac, Kara E.; Burnley, Pamela C.; Adcock, Christopher T.

Here, this study compares high-resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (Nationalmore » Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age.« less

Modeling background radiation using geochemical data: A case study in and around Cameron, Arizona

DOE PAGES

Marsac, Kara E.; Burnley, Pamela C.; Adcock, Christopher T.; ...

2016-09-16

Here, this study compares high-resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (Nationalmore » Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age.« less

Leptospira Exposure and Waste Pickers: A Case-Control Seroprevalence Study in Durango, Mexico

PubMed Central

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

2015-01-01

Background Infection with Leptospira may occur by contact with Leptospira-infected animals. Waste pickers are in contact with rodents and dogs while picking in the garbage. Whether waste pickers are at risk for Leptospira infection is largely unknown. This study was aimed to determine the association of Leptospira IgG seroprevalence with the occupation of waste picking, and to determine the epidemiological characteristics of the waste pickers with Leptospira exposure. Methods Through a case-control study, we determined the seroprevalence of anti-Leptospira IgG antibodies in 90 waste pickers and 90 age- and gender-matched control subjects in Durango City, Mexico using an enzyme immunoassay. Data were analyzed by bivariate and multivariate analyses. Results The prevalence of anti-Leptospira IgG antibodies was similar in waste pickers (4/90: 4.4%) to that in control subjects (5/90: 5.6%) (P = 1.00). Bivariate analysis showed that Leptospira exposure in waste pickers was associated with increasing age (P = 0.009), no education (P = 0.008), and consumption of rat meat (P = 0.04). However, these associations were no longer found by multivariate analysis. Leptospira exposure in waste pickers was not associated with health status, duration in the activity, wearing hand gloves and facemasks, history of injuries with sharp material of the garbage, or contact with animals or soil. Conclusions This is the first study about Leptospira exposure in waste pickers. Results suggest that waste pickers are not at increasing risk for Leptospira exposure in Durango City, Mexico. Further research with a larger sample size to elucidate the association of Leptospira exposure with waste picking activity is needed. PMID:26124911

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.

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.

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.

Cannabis use and cancer of the head and neck: case-control study.

PubMed

Aldington, Sarah; Harwood, Matire; Cox, Brian; Weatherall, Mark; Beckert, Lutz; Hansell, Anna; Pritchard, Alison; Robinson, Geoffrey; Beasley, Richard

2008-03-01

To investigate whether cannabis smoking increases the risk of head and neck cancer. Case-control study. Cases of head and neck cancer < or =55 years identified from hospital databases and the Cancer Registry, and controls randomly selected from the electoral roll completed interviewer-administered questionnaires. Logistic regression was used to estimate the relative risk of head and neck cancer. There were 75 cases and 319 controls. An increased risk of cancer was found with increasing tobacco use, alcohol consumption, and decreased income but not increasing cannabis use. The highest tertile of cannabis use (>8.3 joint years) was associated with a nonsignificant increased risk of cancer (relative risk = 1.6, 95% confidence interval, 0.5-5.2) after adjustment for confounding variables. Cannabis use did not increase the risk of head and neck cancer; however, because of the limited power and duration of use studied, a small or longer-term effect cannot be excluded.

Fibromyalgia: epidemiology and risk factors, a population-based case-control study in Lebanon.

PubMed

Moukaddem, Afaf; Chaaya, Monique; Slim, Zeinab F N; Jaffa, Miran; Sibai, Abla Mehio; Uthman, Imad

2017-02-01

To investigate the epidemiology of fibromyalgia (FM) and assess its risk factors. Using data from the 2009 Community Oriented Program for Control of Rheumatic Diseases (COPCORD) study conducted in Lebanon, a population-based case control study was performed. The sample included 34 FM patients, frequency matched with 136 controls free from any musculoskeletal complaints and randomly sampled from the population. The controls were frequency matched with cases by age and gender. The 34 female FM cases were prevalent cases which existed for a long period of time and all those who consulted a doctor were previously misdiagnosed. Family history of joint problems (OR = 4.93, 95% CI: 1.56-15.58) and working status (OR = 2.69, 95% CI: 1.04-6.93) were significant risk factors for FM, after adjusting for body mass index, distress level, smoking status and residence location. This was the first study to address the epidemiology of FM in Lebanon and the region. The chronic nature of FM that is characterized by frequent bouts of intense disabling pain and symptoms constitutes a significant health and economic burden. Clustering of cases in coastal areas was partially explained by other factors such as body mass index, distress level, smoking and work status. The high burden of FM found in our study calls for further investigation of potential risk factors of this condition. © 2015 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

A retrospective likelihood approach for efficient integration of multiple omics factors in case-control association studies.

PubMed

Balliu, Brunilda; Tsonaka, Roula; Boehringer, Stefan; Houwing-Duistermaat, Jeanine

2015-03-01

Integrative omics, the joint analysis of outcome and multiple types of omics data, such as genomics, epigenomics, and transcriptomics data, constitute a promising approach for powerful and biologically relevant association studies. These studies often employ a case-control design, and often include nonomics covariates, such as age and gender, that may modify the underlying omics risk factors. An open question is how to best integrate multiple omics and nonomics information to maximize statistical power in case-control studies that ascertain individuals based on the phenotype. Recent work on integrative omics have used prospective approaches, modeling case-control status conditional on omics, and nonomics risk factors. Compared to univariate approaches, jointly analyzing multiple risk factors with a prospective approach increases power in nonascertained cohorts. However, these prospective approaches often lose power in case-control studies. In this article, we propose a novel statistical method for integrating multiple omics and nonomics factors in case-control association studies. Our method is based on a retrospective likelihood function that models the joint distribution of omics and nonomics factors conditional on case-control status. The new method provides accurate control of Type I error rate and has increased efficiency over prospective approaches in both simulated and real data. © 2015 Wiley Periodicals, Inc.

Protective effect of intradermal BCG against leprosy; a case-control study in central Brazil.

PubMed

Rodrigues, M L; Silva, S A; Neto, J C; de Andrade, A L; Martelli, C M; Zicker, F

1992-09-01

A case-control study was undertaken to evaluate the protective efficacy of intradermal BCG against leprosy in a high-endemic area of leprosy in central Brazil. Sixty-two cases and 186 controls were included in the study. Cases were all newly diagnosed leprosy patients under 16 years of age attending an outpatient health service, and all of them were schoolchildren. Three controls under 16 years old, frequency matched by sex and age group, were selected from schools geographically located in the area from which the cases came. The presence of BCG was negatively associated with leprosy, indicating a 5.3 risk of leprosy for those nonvaccinated and protective efficacy of 81%. Paucibacillary patients were more likely to have a BCG scar than multibacillary patients.

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.

National Case-Control Study of Homicide Offending and Methamphetamine Use

ERIC Educational Resources Information Center

Stretesky, Paul B.

2009-01-01

The purpose of this study is to examine the relationship between methamphetamine use and homicide. To carry out this study, data from the National Household Survey on Drug Abuse and Survey of Inmates in State and Federal Correctional Facilities were combined to create a case-control design. The main exposure measure is methamphetamine use and the…

Snippets From the Past: Is Flint, Michigan, the Birthplace of the Case-Control Study?

PubMed Central

Morabia, Alfredo

2013-01-01

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. PMID:24064743

Egg consumption and the risk of type 2 diabetes mellitus: a case-control study.

PubMed

Radzevičienė, Lina; Ostrauskas, Rytas

2012-08-01

Type 2 diabetes mellitus appears to involve an interaction between susceptible genetic backgrounds and environmental factors including highly calorific diets. As it is important to identify modifiable risk factors that may help reduce the risk of type 2 diabetes mellitus, the aim of the present study was to determine the association between egg consumption and the risk of type 2 diabetes mellitus. A specifically designed questionnaire was used to collect information on possible risk factors of type 2 diabetes mellitus. The odds ratios and 95 % confidence intervals for type 2 diabetes mellitus were calculated by conditional logistic regression. A case-control study in a Lithuanian out-patient clinic was performed in 2001. A total of 234 cases with a newly confirmed diagnosis of type 2 diabetes mellitus and 468 controls free of the disease. Variables such as BMI, family history of diabetes, cigarette smoking, education, morning exercise and plasma TAG level were retained in multivariate logistic regression models as confounders because their inclusion changed the value of the odds ratio by more than 10 % in any exposure category. After adjustment for possible confounders more than twofold increased risk of type 2 diabetes mellitus was determined for individuals consuming 3-4·9 eggs/week (OR = 2·60; 95 % CI 1·34, 5·08) and threefold increased risk of the disease was determined for individuals consuming ≥5 eggs/week (OR = 3·02; 95 % CI 1·14, 7·98) compared with those eating <1 egg/week. Our data support a possible relationship of egg consumption and increased risk of type 2 diabetes mellitus.

The home environment and asthma symptoms in childhood: two population based case-control studies 13 years apart

PubMed Central

Butland, B. K.; Strachan, D. P.; Anderson, H. R.

1997-01-01

BACKGROUND: Prevalence surveys of asthma and/or wheezing among all children aged between 7 1/2 and 8 1/2 attending state and private schools in the London Borough of Croydon were conducted in February 1978 and February 1991. Two population based case-control studies drawn from the survey responders were used to investigate the association between childhood wheeze and characteristics of the home environment and to assess whether changes in these characteristics between 1978 and 1991 may have contributed to an increase in the population prevalence of wheeze among school children. METHODS: Information on exposure to potential indoor environmental risk factors was obtained from parents by home interview and compared between cases-that is, children with frequent (> or = 5) or in-frequent (1-4) attacks of asthma or wheezing in the past 12 months- and controls, with adjustment for study. Changes in exposure over time were assessed by comparing control groups. RESULTS: Between 1978 and 1991 the population prevalence odds of wheeze increased by 20% (OR 1.20; 95% CI 1.04 to 1.39). Change in parental smoking, gas cooking, pet ownership, and central heating did not appear to explain the rise. Use of non-feather pillows was positively associated with childhood wheeze even after adjusting for other risk factors and after re-coding from non-feather to feather cases thought to have changed pillow in response to symptoms (OR 1.54; 95% CI 1.13 to 2.10). The proportion of control children reportedly using non-feather pillows was 44% in 1978 and 67% in 1991. CONCLUSIONS: Increased use of non-feather pillows was the only domestic indoor exposure studied which appeared to explain a modest rise in prevalence of wheeze from 1978 to 1991. Our analysis attempts to address behavioural change in response to the child's symptoms but an artifact arising from lifelong avoidance of feather bedding in atopic families cannot be entirely discounted. 


 PMID:9246133

Dentine sensitivity risk factors: A case-control study.

PubMed

Mafla, Ana Cristina; Lopez-Moncayo, Luis Fernando

2016-01-01

To identify the clinical and psychological risk factors associated with dentine hypersensitivity (DH) in order to provide an early diagnosis and preventive therapy. A nested case-control study was design between 2011 and 2012. A total of 61 DH cases and 122 controls participated in this investigation. Cases and controls were matched for sex, group of age and socioeconomic status in a ratio of 1:2. DH to different stimuli such as cold, heat, acid, and sweet was asked in patient interviews, and dental examinations were used to detect DH. Clinical and psychological risk factors such as dental hygiene, periodontal disease, acid diet, alcohol consumption, psychological stress, and psychopathological symptoms were inquired. Psychological stress was measured through the PSS-10 and psychopathological symptoms were evaluated by SCL-90-R in Spanish. Descriptive and univariate binary logistic regression analysis were performed to estimate the association between clinical and psychological risk factors and the presence of DH. Toothpaste abrasivity (odds ratio [OR] 1.881, 95% confidence interval [CI] 1.010-3.502, P = 0.045), gingival recession (OR 2.196, 95% CI 1.020-4.728, P = 0.041), and periodontal therapy (OR 5.357, 95% CI 2.051-13.993, P < 0.001) were associated with DH. Subjects with perceived stress (OR 1.211, 95%, CI 0.518-2.833, P = 0.658), obsessive-compulsive (OR 1.266, 95%, CI 0.494-3.240, P = 0.623) and hostility (OR 1.235, 95%, CI 0.507-3.007, P = 0.642) symptoms had a clinical greater odd of DH. Oral hygiene products and periodontal conditions are important risk factors for DH. Individuals with perceived stress, obsessive-compulsive, and hostility symptoms may increase a clinical risk for this entity. Targeting to dental counseling focused on oral hygiene products, periodontal therapy and a psychological evaluation may be promising in DH prevention.

Association Between Epicardial Fat Thickness and Premature Coronary Artery Disease: A Case Control Study

PubMed Central

Faghihi, Shadi; Vasheghani-Farahani, Ali; Parsaee, Mozhgan; Saedi, Sedigheh; Ghadrdoost, Behshid

2015-01-01

Background: The association between epicardial fat thickness (EFT) and premature coronary artery disease (CAD) has not been elaborately studied. Objectives: In the present study, we sought whether such a relationship between EFT and CAD exists. Patients and Methods: Sixty two consecutive subjects, under 50 years of age, who underwent coronary angiography (CAG) with the aspect of CAD, were included in this case control study. They were divided into two groups of 31 subjects, namely CAD (cases) and non-CAD (controls) group, according to CAG data. Presence of conventional coronary risk factors, drug history, and anthropometric data were recorded. Then, each subject underwent standard transthoracic echocardiography for measuring EFT in the proximal part of right ventricular outflow tract in the parasternal long axis view at end diastole, as well as other parameters of systolic and diastolic function, and left ventricle (LV) mass. Images were stored for offline analysis when the echocardiocardiographers were blind to CAG data. Results: Among baseline characteristics, waist circumference, triglyceride levels, cigarette smoking and history of statin use were significantly higher in the CAD group. The body mass index (BMI) was significantly higher in the non-CAD group. According to echocardiographic data, the EFT with a cut off value of 2.95 mm could well differentiate subjects in each group. The LV mass and E/e were significantly higher in CAD group, in addition to EFT. Also, there was a significant correlation between EFT and waist circumference, as well as LV mass. However, no significant relation was between EFT and LV systolic and diastolic function. Conclusions: The EFT, as measured by echocardiography, with a cut off value 2.95 mm has a strong association with premature CAD. PMID:26380819

Masticatory muscle sleep background electromyographic activity is elevated in myofascial temporomandibular disorder patients.

PubMed

Raphael, K G; Janal, M N; Sirois, D A; Dubrovsky, B; Wigren, P E; Klausner, J J; Krieger, A C; Lavigne, G J

2013-12-01

Despite theoretical speculation and strong clinical belief, recent research using laboratory polysomnographic (PSG) recording has provided new evidence that frequency of sleep bruxism (SB) masseter muscle events, including grinding or clenching of the teeth during sleep, is not increased for women with chronic myofascial temporomandibular disorder (TMD). The current case-control study compares a large sample of women suffering from chronic myofascial TMD (n = 124) with a demographically matched control group without TMD (n = 46) on sleep background electromyography (EMG) during a laboratory PSG study. Background EMG activity was measured as EMG root mean square (RMS) from the right masseter muscle after lights out. Sleep background EMG activity was defined as EMG RMS remaining after activity attributable to SB, other orofacial activity, other oromotor activity and movement artefacts were removed. Results indicated that median background EMG during these non-SB event periods was significantly higher (P < 0·01) for women with myofascial TMD (median = 3·31 μV and mean = 4·98 μV) than for control women (median = 2·83 μV and mean = 3·88 μV) with median activity in 72% of cases exceeding control activity. Moreover, for TMD cases, background EMG was positively associated and SB event-related EMG was negatively associated with pain intensity ratings (0-10 numerical scale) on post-sleep waking. These data provide the foundation for a new focus on small, but persistent, elevations in sleep EMG activity over the course of the night as a mechanism of pain induction or maintenance. © 2013 John Wiley & Sons Ltd.

Urine output on an intensive care unit: case-control study

PubMed Central

Kirwan, Christopher J; Alexander, Neal D E; Nimako, Kofi; Jurukov, Angela; Forth, Rebecca J; Rahman, Tony M

2010-01-01

Objective To compare urine output between junior doctors in an intensive care unit and the patients for whom they are responsible. Design Case-control study. Setting General intensive care unit in a tertiary referral hospital. Participants 18 junior doctors responsible for clerking patients on weekday day shifts in the unit from 23 March to 23 April 2009 volunteered as “cases.” Controls were the patients in the unit clerked by those doctors. Exclusion criteria (for both groups) were pregnancy, baseline estimated glomerular filtration rate <15 ml/min/1.73 m2, and renal replacement therapy. Main outcome measures Oliguria (defined as mean urine output <0.5 ml/kg/hour over six or more hours of measurement) and urine output (in ml/kg/hour) as a continuous variable. Results Doctors were classed as oliguric and “at risk” of acute kidney injury on 19 (22%) of 87 shifts in which urine output was measured, and oliguric to the point of being “in injury” on one (1%) further shift. Data were available for 208 of 209 controls matched to cases in the data collection period; 13 of these were excluded because the control was receiving renal replacement therapy. Doctors were more likely to be oliguric than their patients (odds ratio 1.99, 95% confidence interval 1.08 to 3.68, P=0.03). For each additional 1 ml/kg/hour mean urine output, the odds ratio for being a case rather than a control was 0.27 (0.12 to 0.58, P=0.001). Mortality among doctors was astonishingly low, at 0% (0% to 18%). Conclusions Managing our own fluid balance is more difficult than managing it in our patients. We should drink more water. Modifications to the criteria for acute kidney injury could be needed for the assessment of junior doctors in an intensive care unit. PMID:21156738

Urine output on an intensive care unit: case-control study.

PubMed

Solomon, Anthony W; Kirwan, Christopher J; Alexander, Neal D E; Nimako, Kofi; Jurukov, Angela; Forth, Rebecca J; Rahman, Tony M

2010-12-14

To compare urine output between junior doctors in an intensive care unit and the patients for whom they are responsible. Case-control study. General intensive care unit in a tertiary referral hospital. 18 junior doctors responsible for clerking patients on weekday day shifts in the unit from 23 March to 23 April 2009 volunteered as "cases." Controls were the patients in the unit clerked by those doctors. Exclusion criteria (for both groups) were pregnancy, baseline estimated glomerular filtration rate <15 ml/min/1.73 m(2), and renal replacement therapy. Oliguria (defined as mean urine output <0.5 ml/kg/hour over six or more hours of measurement) and urine output (in ml/kg/hour) as a continuous variable. Doctors were classed as oliguric and "at risk" of acute kidney injury on 19 (22%) of 87 shifts in which urine output was measured, and oliguric to the point of being "in injury" on one (1%) further shift. Data were available for 208 of 209 controls matched to cases in the data collection period; 13 of these were excluded because the control was receiving renal replacement therapy. Doctors were more likely to be oliguric than their patients (odds ratio 1.99, 95% confidence interval 1.08 to 3.68, P=0.03). For each additional 1 ml/kg/hour mean urine output, the odds ratio for being a case rather than a control was 0.27 (0.12 to 0.58, P=0.001). Mortality among doctors was astonishingly low, at 0% (0% to 18%). Managing our own fluid balance is more difficult than managing it in our patients. We should drink more water. Modifications to the criteria for acute kidney injury could be needed for the assessment of junior doctors in an intensive care unit.

Consanguinity and epilepsy in Oran, Algeria: A case-control study.

PubMed

Chentouf, Amina; Talhi, Randa; Dahdouh, Aicha; Benbihi, Latifa; Benilha, Soumia; Oubaiche, Mohand Laid; Chaouch, Malika

2015-03-01

The goal of this case-control study was to identify the significance of consanguinity and other risk factors for epilepsy in Oran, Algeria. Unrelated epileptic patients upwards of 16 years, who attended the Neurology Department between October 2013 and March 2014 were included in the study. Controls, matched for age and sex, were selected among non-epileptic patients attending the same department during the same period. The risk factors evaluated were: consanguinity, family history of epilepsy, perinatal complications, infection of the central nervous system, mental retardation, neurological impairment, history of febrile seizures, severe head trauma, cerebrovascular diseases, and addiction. 101 cases and 202 controls participated in the study. Multivariate logistic regression identified five factors significantly associated with epilepsy: first-degree of consanguinity (odds ratio (OR)=2.15), history of epilepsy in first-degree relatives (OR=4.03), antecedent of febrile seizures (OR=5.38), severe head injury (OR=2.94) and mental retardation (OR=9.32). Consanguinity, family history of epilepsy, history of febrile seizures, severe head trauma and mental retardation are risk factors for epilepsy. The implementation of a strategy for prevention and awareness of the impact of consanguineous marriages as well as genetic counseling for couples with a family history of epilepsy are needed. Copyright © 2015 Elsevier B.V. All rights reserved.

[Lung cancer and vegetable consumption in Asturias, Spain. A case control study].

PubMed

Caicoya, Martín

2002-07-13

Lung cancer in Asturias (Northern Spain) exceeds the Spanish average by 1.4 times. While the proportion of smokers is similar, consumption of vegetables is the lowest of Spain. The objective of the study was to examine the relationship between lung cancer and vegetable consumption in Asturias. This was an incident, hospital-based, case-control study. Cases were newly diagnosed lung cancer patients and controls were patients from surgical wards. Diet habits were obtained by means of a food frequency questionnaire with one year recall time. Information was also sought on smoking, occupational exposure and demographic variables. 197 cases and 196 controls were included in the study. Those at the 80th percentile of cruciferous (e.g, cabbage, broccoli) consumption had half the risk of lung cancer, other than adenocarcinoma, as compared to those at the 20th percentile [OR = 0.47; 95% CI, 0.23-0.95 in the crude analysis]. However, when adjusting for smoking and social class, the association was no longer significant, possibly due to a low power of the study. A high vegetable, vitamin A or betacarotene consumption was not associated with a lower risk of lung cancer. This study points towards a protective effect of cruciferous vegetables in lung cancer, other than adenocarcinoma. However, even in the case such a vegetable were protective, it could not explain by itself the existing differences in lung cancer rates between Asturias and the the rest of Spain.

Design and validity of a clinic-based case-control study on the molecular epidemiology of lymphoma

PubMed Central

Cerhan, James R; Fredericksen, Zachary S; Wang, Alice H; Habermann, Thomas M; Kay, Neil E; Macon, William R; Cunningham, Julie M; Shanafelt, Tait D; Ansell, Stephen M; Call, Timothy G; Witzig, Thomas E; Slager, Susan L; Liebow, Mark

2011-01-01

We present the design features and implementation of a clinic-based case-control study on the molecular epidemiology of lymphoma conducted at the Mayo Clinic (Rochester, Minnesota, USA), and then assess the internal and external validity of the study. Cases were newly diagnosed lymphoma patients from Minnesota, Iowa and Wisconsin seen at Mayo and controls were patients from the same region without lymphoma who had a pre-scheduled general medical examination, frequency matched on age, sex and residence. Overall response rates were 67% for cases and 70% for controls; response rates were lower for cases and controls over age 70 years, cases with more aggressive disease, and controls from the local area, although absolute differences were modest. Cases and controls were well-balanced on age, sex, and residence characteristics. Demographic and disease characteristics of NHL cases were similar to population-based cancer registry data. Control distributions were similar to population-based data on lifestyle factors and minor allele frequencies of over 500 SNPs, although smoking rates were slightly lower. Associations with NHL in the Mayo study for smoking, alcohol use, family history of lymphoma, autoimmune disease, asthma, eczema, body mass index, and single nucleotide polymorphisms in TNF (rs1800629), LTA (rs909253), and IL10 (rs1800896) were at a magnitude consistent with estimates from pooled studies in InterLymph, with history of any allergy the only directly discordant result in the Mayo study. These data suggest that this study should have strong internal and external validity. This framework may be useful to others who are designing a similar study. PMID:21686124

OPTIMIZED REAL-TIME CONTROL OF COMBINED SEWERAGE SYSTEMS: TWO CASE STUDIES

EPA Science Inventory

The paper presents results of two case studies of Real-Time Control (RTC) alternatives evaluations that were conducted on portions of sewerage systems near Paris, France and in Quebec City, Canada, respectively. The studies were performed at real-scale demonstration sites. RTC ...

Modeling background radiation using geochemical data: A case study in and around Cameron, Arizona.

PubMed

Marsac, Kara E; Burnley, Pamela C; Adcock, Christopher T; Haber, Daniel A; Malchow, Russell L; Hausrath, Elisabeth M

2016-12-01

This study compares high resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (National Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Severe maternal morbidity: a case-control study in Maranhao, Brazil

PubMed Central

2013-01-01

Background Maternal mortality and morbidity are among the top public health priorities in Brazil, being quite high, especially among the most disadvantage women. A case control study was developed to identify risk factors for severe maternal morbidity in Sao Luis, one of the poorest Brazilian State Capitals. Methods The case–control study was carried out between 01/03/2009 and 28/02/2010 in two public high-risk maternities facilities and in two intensive care units (ICUs) for referral of obstetric cases. All cases hospitalized due to complications during gestation period, childbirth or up to 42 days of puerperium and who fulfilled any of Mantel's and/or Waterstone's criteria were identified. Two controls per case were randomly selected among patients of the same clinics discharged for other reasons. Data were obtained through a structured interview as well as from medical charts and prenatal cards and included sociodemographic variables, clinical and obstetric histories, behavioral factors and exposure to stress factors during pregnancy, pre-natal assistance and obstetric complication and childbirth care. Results In the final model of the unconditional logistic regression analysis, being older than 35 years (OR=3.11; 95% CI:1.53-6.31), previous hypertension (OR=2.52; 95% CI:1.09-5.80), history of abortion (OR=1.61; 95% CI:0.97-2.68), 4–5 pre-natal consultations (OR=1.78; 95% CI:1.05-3.01) and 1–3 pre-natal consultations (OR=1.89; 95% CI:1.03-3.49) were independently associated with severe maternal morbidity. Conclusions The results corroborate the importance of reproductive healthcare, of identifying a high-risk pregnancy and of a qualified and complete prenatal care to prevent severe morbid events. Resumo Introdução A mortalidade e morbidade maternas estão entre os tópicos prioritários da Saúde Pública brasileira, especialmente na população de menor nível socioeconômico. Um estudo caso-controle foi desenvolvido para identificar os fatores de risco

Demographic risk factors of self-immolation: a case-control study.

PubMed

Ahmadi, Alireza; Mohammadi, Reza; Schwebel, David C; Khazaie, Habibolah; Yeganeh, Naser; Almasi, Afshin

2009-06-01

To investigate demographic risk factors for self-immolation patients. In a case-control study, 30 consecutive cases of deliberate self-inflicted burns admitted to the regional Burn centre (Imam Khomeini hospital in Kermanshah province, Iran) were compared with 30 controls who were selected from the community and matched by gender, age, and living area. All cases and controls were reviewed for demographic variables, including: age, gender, living area, family size, marital status, bearing and number of children, Body Mass Index (BMI), birth order, employment state, educational status, early school drop-out, and parent/guardian employment status. Two variables emerged as related to risk of self-immolation. Being the first or last child in family birth order was associated with increased risk of self-immolation. Moreover, among the married participants, having children was associated with decreased risk of self-immolation. The comparisons of other variables were not statistically significant. In multivariate analyses, none of the variables predicted risk for self-immolation. This study suggests that being the first or last child of a family might be a risk factor for self-immolation. For married persons, having children might serve as a protective factor from self-immolation. Other variables such as family size, marital status, number of children, BMI, employment state, educational status, early school drop-out, and parent/guardian employment status did not play a role as individually protective or risk factors for self-immolation.

Dietary Flavonoid Intake and Lung Cancer—A Population-based Case-control Study

PubMed Central

Cui, Yan; Morgenstern, Hal; Greenland, Sander; Tashkin, Donald P.; Mao, Jenny T.; Cai, Lin; Cozen, Wendy; Mack, Thomas M.; Lu, Qing-Yi; Zhang, Zuo-Feng

2017-01-01

BACKGROUND Laboratory studies suggest that flavonoids are antimutagenic and anticarcinogenic. To investigate the associations between commonly consumed flavonoid compounds and lung cancer, the authors conducted a population-based case–control study of 558 lung cancer cases and a group of 837 controls. METHODS Dietary intakes of flavonoids were estimated by combining the intake frequency (collected by a food frequency questionnaire), portion size, and food composition data. Unconditional logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence limits (95% CLs) with an adjustment for potential confounders, including age, sex, race-ethnicity, years of schooling, smoking status, pack-years of tobacco smoking, and daily energy intake. RESULTS Lung cancer was associated inversely with the consumption of epicatechin (in 10 mg per day increment: OR, 0.64; 95% CL, 0.46–0.88), catechin (4 mg per day increment: OR, 0.49; 95% CL, 0.35–0.70), quercetin (9 mg per day increment: OR, 0.65; 95% CL, 0.44–0.95), and kaempferol (2 mg per day increment: OR, 0.68; 95% CL, 0.51–0.90) among tobacco smokers. There was little association between lung cancer and the flavonoid compounds mentioned above among nonsmokers. Regardless of smoking status, there was little association with total flavonoids: thearubigins, hesperetin, naringenin, and myricetin. In addition, consumption of vegetables, tea, and wine, all of which are rich sources of flavonoids, was associated inversely with lung cancer among tobacco smokers. CONCLUSIONS Certain flavonoid compounds, including epicatechin, catechin, quercetin, and kaempferol, were associated inversely with lung cancer among tobacco smokers, but not among nonsmokers. Further studies of these associations may be warranted. PMID:18327817

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.

Selection bias in population-based cancer case-control studies due to incomplete sampling frame coverage.

PubMed

Walsh, Matthew C; Trentham-Dietz, Amy; Gangnon, Ronald E; Nieto, F Javier; Newcomb, Polly A; Palta, Mari

2012-06-01

Increasing numbers of individuals are choosing to opt out of population-based sampling frames due to privacy concerns. This is especially a problem in the selection of controls for case-control studies, as the cases often arise from relatively complete population-based registries, whereas control selection requires a sampling frame. If opt out is also related to risk factors, bias can arise. We linked breast cancer cases who reported having a valid driver's license from the 2004-2008 Wisconsin women's health study (N = 2,988) with a master list of licensed drivers from the Wisconsin Department of Transportation (WDOT). This master list excludes Wisconsin drivers that requested their information not be sold by the state. Multivariate-adjusted selection probability ratios (SPR) were calculated to estimate potential bias when using this driver's license sampling frame to select controls. A total of 962 cases (32%) had opted out of the WDOT sampling frame. Cases age <40 (SPR = 0.90), income either unreported (SPR = 0.89) or greater than $50,000 (SPR = 0.94), lower parity (SPR = 0.96 per one-child decrease), and hormone use (SPR = 0.93) were significantly less likely to be covered by the WDOT sampling frame (α = 0.05 level). Our results indicate the potential for selection bias due to differential opt out between various demographic and behavioral subgroups of controls. As selection bias may differ by exposure and study base, the assessment of potential bias needs to be ongoing. SPRs can be used to predict the direction of bias when cases and controls stem from different sampling frames in population-based case-control studies.

The Relevance of Maternal Socioeconomic Characteristics for Low Birth Weight – a Case-Control Study

PubMed Central

Altenhöner, T.; Köhler, M.; Philippi, M.

2016-01-01

Introduction: The number of children born underweight (low birth weight, LBW) is increasing despite extensive prevention and screening programmes. The cost is high for the health system, and affected children are burdened with health predictors that can affect them negatively throughout their lives. This study investigates to what extent socioeconomic factors, in addition to known medical causes and the health behaviour of pregnant women, influence LBW. Materials and Methods: In this case-control study 131 mothers of singletons with a birth weight ≤ 2500 g (cases) and 323 mothers of normal birth weight babies (controls) were interviewed with respect to socioeconomic status, health behaviour and stress in the workplace. Medical data were collected by specialist staff using a questionnaire. Results: Independent of medical diagnosis and health behaviour, women with lower level education (OR [95 % CI] = 2.24 [1.12; 4.51]) and those who were not working (OR [95 % CI] = 1.82 [1.10; 3.00]) were more likely to have an LBW baby. No effect was shown for immigrant background (OR [95 % CI] = 1.14 [0.59; 2.21]) or stress in the workplace (OR [95 % CI] = 1.17 [0.90; 1.51]). Discussion and Conclusion: These results show that the association between social and health inequalities starts from before birth. In order to reduce the rising number of babies born underweight, socioeconomic determinants in the care and supervision of pregnant women should systematically receive more attention to enable appropriate early preventive strategies to be implemented. PMID:27065486

An alternative experimental case-control design for genetic association studies on bovine mastitis.

PubMed

Biffani, S; Del Corvo, M; Capoferri, R; Pedretti, A; Luini, M; Williams, J L; Pagnacco, G; Minvielle, F; Minozzi, G

2017-04-01

The possibility of using genetic control strategies to increase disease resistance to infectious diseases relies on the identification of markers to include in the breeding plans. Possible incomplete exposure of mastitis-free (control) animals, however, is a major issue to find relevant markers in genetic association studies for infectious diseases. Usually, designs based on elite dairy sires are used in association studies, but an epidemiological case-control strategy, based on cows repeatedly field-tested could be an alternative for disease traits. To test this hypothesis, genetic association results obtained in the present work from a cohort of Italian Holstein cows tested for mastitis over time were compared with those from a previous genome-wide scan on Italian Holstein sires genotyped with 50k single nucleotide polymorphisms for de-regressed estimated breeding values for somatic cell counts (SCCs) on Bos taurus autosome (BTA6) and BTA14. A total of 1121 cows were selected for the case-control approach (cases=550, controls=571), on a combination of herd level of SCC incidence and of within herd individual level of SCC. The association study was conducted on nine previously identified markers, six on BTA6 and four on BTA14, using the R statistical environment with the 'qtscore' function of the GenABEL package, on high/low adjusted linear score as a binomial trait. The results obtained in the cow cohort selected on epidemiological information were in agreement with those obtained from the previous sire genome-wide association study (GWAS). Six out of the nine markers showed significant association, four on BTA14 (rs109146371, rs109234250, rs109421300, rs109162116) and two on BTA6 (rs110527224 and rs42766480). Most importantly, using mastitis as a case study, the current work further validated the alternative use of historical field disease data in case-control designs for genetic analysis of infectious diseases in livestock.

Reduced Haematopoietic Output in Automobile Mechanics and Sprayers with Chronic Exposure to Petrochemicals: A Case-Control Study in Cape Coast, Ghana

PubMed Central

Pobee, Richard; Awuah, Aaron; Asiamah, Paul B.; Amoani, Festus; Gyabaa, Sampson

2018-01-01

Background Automobile mechanics and sprayers are at a higher risk of exposure to hazardous chemicals such as polycyclic aromatic hydrocarbons and heavy metals which may cause adverse health outcomes. This study aimed to use reticulocyte count as an indirect measure of the haematological output in automobile mechanics and sprayers in the Cape Coast Metropolis, Ghana. Method This cross-sectional study recruited 130 participants: 90 cases (57 automobile mechanics and 33 automobile sprayers) and 40 controls (nonautomobile workers). Venous blood samples were drawn from the participants and examined for full blood count and absolute reticulocyte count. Semi-structured questionnaire was used to collect demographic and occupational safety information from participants. Results 75.6% of cases had never received occupational safety training. Whereas 35.1% of automobile mechanics routinely siphoned fuel, 36.4% of automobile sprayers never used nose masks in the discharge of their duties. Controls had significantly higher WBC counts compared to mechanics (p = 0.0001; 5.04 ± 1.7 versus 3.81 ± 1.1), or sprayers (p = 0.0004; 5.04 ± 1.7 versus 3.74 ± 0.9). Lymphocyte, monocyte, and platelet counts were also significantly higher in controls compared to cases. Whereas RBC counts were significantly higher in controls compared to automobile mechanics (4.85 versus 4.66; p = 0.034), haemoglobin levels were significantly higher in automobile sprayers compared to controls (15.13 versus 14.1 g/dl; p = 0.0126). Absolute reticulocyte count was significantly higher in controls compared to cases [p < 0.0001; (56.88 ± 32.14) × 109/L (controls) versus (25.31 ± 15.75) × 109/L (sprayers) or (33.27 ± 24.42) × 109/L (mechanics)]. Among the cases however, only RBC counts were significantly lower in automobile mechanics compared to automobile sprayers (p = 0.0088; 4.66 ± 0.4 versus 4.85 ± 0.5). Conclusion It was evident that both automobile mechanics and sprayers had significantly reduced

Functional Impairment in Adult Sleepwalkers: A Case-Control Study

PubMed Central

Lopez, Regis; Jaussent, Isabelle; Scholz, Sabine; Bayard, Sophie; Montplaisir, Jacques; Dauvilliers, Yves

2013-01-01

Study Objectives: To investigate the restorative quality of sleep and daytime functioning in sleepwalking adult patients in comparison with controls. Design: Prospective case-control study. Setting: Data were collected at the Sleep Disorders Center, Hôpital-Gui-de Chauliac, Montpellier, France between June 2007 and January 2011. Participants: There were 140 adult sleepwalkers (100 (median age 30 y, 55% male) in whom primary SW was diagnosed) who underwent 1 night of video polysomnography. All patients participated in a standardized clinical interview and completed a battery of questionnaires to assess clinical characteristics of parasomnia, daytime sleepiness, fatigue, insomnia, depressive and anxiety symptoms, and health-related quality of life. Results were compared with those of 100 sex- and age-matched normal controls. Interventions: N/A. Measurements and Results: Of the sleepwalkers, 22.3% presented with daily episodes and 43.5% presented with weekly episodes. Median age at sleepwalking onset was 9 y. Familial history of sleepwalking was reported in 56.6% of sleepwalkers and violent sleep related behaviors in 57.9%, including injuries requiring medical care for at least one episode in 17%. Significant associations were found between sleepwalking and daytime sleepiness, fatigue, insomnia, depressive and anxiety symptoms, and altered quality of life. Early-onset sleepwalkers had higher frequency of violent behaviors and injuries. Sleepwalkers with violent behaviors had higher frequency of sleep terrors and triggering factors, with greater alteration in health-related quality of life. Conclusion: Adult sleepwalking is a potentially serious condition that may induce violent behaviors, self-injury or injury to bed partners, sleep disruption, excessive daytime sleepiness, fatigue, and psychological distress, all of which affect health-related quality of life. Citation: Lopez R; Jaussent I; Scholz S; Bayard S; Montplaisir J; Dauvilliers Y. Functional impairment in

High glycemic load diet, milk and ice cream consumption are related to acne vulgaris in Malaysian young adults: a case control study

PubMed Central

2012-01-01

Background The role of dietary factors in the pathophysiology of acne vulgaris is highly controversial. Hence, the aim of this study was to determine the association between dietary factors and acne vulgaris among Malaysian young adults. Methods A case–control study was conducted among 44 acne vulgaris patients and 44 controls aged 18 to 30 years from October 2010 to January 2011. Comprehensive acne severity scale (CASS) was used to determine acne severity. A questionnaire comprising items enquiring into the respondent’s family history and dietary patterns was distributed. Subjects were asked to record their food intake on two weekdays and one day on a weekend in a three day food diary. Anthropometric measurements including body weight, height and body fat percentage were taken. Acne severity was assessed by a dermatologist. Results Cases had a significantly higher dietary glycemic load (175 ± 35) compared to controls (122 ± 28) (p < 0.001). The frequency of milk (p < 0.01) and ice-cream (p < 0.01) consumptions was significantly higher in cases compared to controls. Females in the case group had a higher daily energy intake compared to their counterparts in the control group, 1812 ± 331 and 1590 ± 148 kcal respectively (p < 0.05). No significant difference was found in other nutrient intakes, Body Mass Index, and body fat percentage between case and control groups (p > 0.05). Conclusions Glycemic load diet and frequencies of milk and ice cream intake were positively associated with acne vulgaris. PMID:22898209

Estimating risk and rate levels, ratios and differences in case-control studies.