Studies of disease causation

2018 ◽  
pp. 71-89
Author(s):  
Alan J. Silman ◽  
Gary J. Macfarlane ◽  
Tatiana Macfarlane
Keyword(s):  
Cohort Studies ◽  
Epidemiological Study ◽  
Disease Status ◽  
Case Control ◽  
Careful Selection ◽  
Sampling Frame ◽  
Case Control Studies ◽  
Disease Causation ◽  
Selection Of

The most important aspect that will influence the validity of any epidemiological study is the careful selection of the subjects for investigation. Separate issues relate to the sampling of subjects for disease status in case–control studies, and sampling by exposure status in cohort studies. In simplest terms, the issues are who should be the cases and, given that, who should be the controls. Thus, in each instance the needs are to identify the sampling frame and then what should be the process for selecting the specific sample or subsamples needed for study. In addition to consideration of who to study, other factors such as how to identify and verify plus the size of the planned study are all topics to be addressed.

Introduction to epidemiological study designs

2020 ◽  
pp. 83-98
Author(s):  
Tamsin Ford ◽  
Jayati Das-Munshi ◽  
Martin Prince
Keyword(s):  
Mixed Methods ◽  
Data Collection ◽  
Cohort Studies ◽  
Epidemiological Study ◽  
Study Design ◽  
Case Control ◽  
Psychiatric Epidemiology ◽  
Case Control Studies ◽  
Cross Sectional ◽  
Study Designs

This chapter provides a brief overview for each of the main types of study design commonly used in psychiatric epidemiology. The chapter begins with a discussion of the importance of study design. This is followed by a section on classifying study design, including descriptive studies, ecological studies, cross-sectional surveys, cohort studies, case–control studies, intervention studies, and qualitative and mixed methods studies. The chapter concludes with a description of the basic steps which should be observed in the conduct of studies employing quantitative methodologies (including cross-sectional, cohort, and case–control studies), as well as discussing interviews/assessments, and data collection and processing.

Ethnic differences in risk factors for subarachnoid hemorrhage

2007 ◽  
Vol 107 (3) ◽  
pp. 522-529 ◽  
Author(s):  
Vibhor Krishna ◽  
Dong H. Kim
Keyword(s):  
Risk Factors ◽  
Subarachnoid Hemorrhage ◽  
Alcohol Consumption ◽  
Cohort Studies ◽  
Odds Ratio ◽  
Case Control ◽  
Ethnic Composition ◽  
Effect Estimate ◽  
Case Control Studies ◽  
Current Smoking

Object Studies on risk factors for subarachnoid hemorrhage (SAH) show heterogeneity. For example, hypertension has been found to be a significant risk factor in some studies but not in others. The authors hypothesized that differences in the ethnicity of the populations studied could account for these findings. Methods A metaanalysis was performed using 17 case-control and 10 cohort studies that met specified inclusion criteria. The authors used a random-effect model to calculate the pooled effect estimates for current smoking, hypertension, and alcohol consumption. A meta–regression analysis was performed using the ethnic composition of the study populations as a covariate. Studies were classified as multiethnic or monoethnic, and the pooled effect estimates were compared. Results Analysis of the cohort studies yielded a pooled effect estimate or risk ratio of 3.18 (95% confidence interval [CI] 2.37–4.26) for current smoking, 3.05 (95% CI 2.09–4.44) for hypertension, and 2.46 (95% CI 1.42–4.24) for alcohol consumption at a rate of 150 g/week or more. The results were similar for the case-control studies. For current smoking, the ethnic composition of the study population was a statistically significant predictor of heterogeneity among case-control studies (p < 0.001, even after application of the Bonferroni correction). The risk for SAH among current smokers was higher in multiethnic populations (odds ratio 3.832) than in monoethnic populations (odds ratio 2.487). Conclusions The results of this metaanalysis suggest that differences in susceptibility to the harmful health effects of smoking may be one cause of the observed differences in SAH incidence for different ethnic groups. The role of ethnicity in risk factors for SAH should be considered in future studies.

Soy Consumption with Risk of Coronary Heart Disease and Stroke: A Meta-Analysis of Observational Studies

2016 ◽  
Vol 46 (4) ◽  
pp. 242-252 ◽  
Author(s):  
Danfei Lou ◽  
Yuehua Li ◽  
Guoliang Yan ◽  
Jianhong Bu ◽  
Haihui Wang
Keyword(s):  
Coronary Heart Disease ◽  
Heart Disease ◽  
Cohort Studies ◽  
Observational Studies ◽  
Meta Analysis ◽  
Case Control ◽  
Inverse Association ◽  
Case Control Studies ◽  
Relative Risks ◽  
Product Consumption

Background: The association of soy product consumption with the relative risk of cardiovascular disease remains controversial. This meta-analysis aimed at investigating whether an association exists between soy consumption and the risk of stroke and coronary heart disease (CHD) in observational studies. Methods: A systematic search of the PubMed and EMBASE databases was performed for case-control and cohort studies that assessed soy consumption and the risk of stroke and CHD. Summary relative risks (SRRs) and 95% CIs were combined by using a random-effects model. Results: Of a total of 1,266 abstracts, 5 prospective cohort and 6 case-control studies met our inclusion criteria, and comprised 4,954 stroke and 7,616 CHD events. Based on the high vs. low analyses, combining cohort studies showed no association between soy intake and risk of stroke (SRR 0.92; 95% CI 0.70-1.10; Pheterogeneity = 0.236; I2 = 29.4%) or CHD (SRR 0.97; 95% CI 0.74-1.27; Pheterogeneity = 0.020; I2 = 62.7%), although a significantly inverse association between soy intake and the risk of stroke (SRR 0.54; 95% CI 0.34-0.87; Pheterogeneity = 0.001; I2 = 79.3%) and CHD (SRR 0.66; 95% CI 0.56-0.77; Pheterogeneity = 0.421; I2 = 0) was observed in case-control studies. No association between soy isoflavone intake and the risk of stroke and CHD was identified. Conclusion: There was limited evidence to indicate that soy consumption was inversely associated with the risk of stroke and CHD, although further studies, with prospective designs that use validated questionnaires and control for important confounders, are warranted.

scholarly journals Dietary patterns and CVD: a systematic review and meta-analysis of observational studies

2015 ◽  
Vol 114 (9) ◽  
pp. 1341-1359 ◽  
Author(s):  
Míriam Rodríguez-Monforte ◽  
Gemma Flores-Mateo ◽  
Emília Sánchez
Keyword(s):  
Cohort Studies ◽  
Dietary Patterns ◽  
Observational Studies ◽  
Protective Factor ◽  
Meta Analysis ◽  
Epidemiological Studies ◽  
Case Control ◽  
Case Control Studies ◽  
Chd Risk ◽  
Control Comparison

AbstractEpidemiological studies show that diet is linked to the risk of developing CVD. The objective of this meta-analysis was to estimate the association between empirically derived dietary patterns and CVD. PubMed was searched for observational studies of data-driven dietary patterns that reported outcomes of cardiovascular events. The association between dietary patterns and CVD was estimated using a random-effects meta-analysis with 95 % CI. Totally, twenty-two observational studies met the inclusion criteria. The pooled relative risk (RR) for CVD, CHD and stroke in a comparison of the highest to the lowest category of prudent/healthy dietary patterns in cohort studies was 0·69 (95 % CI 0·60, 0·78; I2=0 %), 0·83 (95 % CI 0·75, 0·92; I2=44·6 %) and 0·86 (95 % CI 0·74, 1·01; I2=59·5 %), respectively. The pooled RR of CHD in a case–control comparison of the highest to the lowest category of prudent/healthy dietary patterns was 0·71 (95 % CI 0·63, 0·80; I2=0 %). The pooled RR for CVD, CHD and stroke in a comparison of the highest to the lowest category of western dietary patterns in cohort studies was 1·14 (95 % CI 0·92, 1·42; I2=56·9 %), 1·03 (95 % CI 0·90, 1·17; I2=59·4 %) and 1·05 (95 % CI 0·91, 1·22; I2=27·6 %), respectively; in case–control studies, there was evidence of increased CHD risk. Our results support the evidence of the prudent/healthy pattern as a protective factor for CVD.

SELECTION OF CONTROLS FOR HOSPITAL-BASED CASE-CONTROL STUDIES USING RETROSPECTIVE DATA ON THE GEOGRAPHIC DISTRIBUTION OF CASES AND CONTROLS

Epidemiology ◽  
2004 ◽  
Vol 15 (4) ◽  
pp. S153-S154 ◽  
Author(s):  
Tony Fletcher ◽  
Giovanni Leonardi ◽  
Kvetoslava Koppova ◽  
Rupert Hough ◽  
Peter Rudnai ◽  
...  
Keyword(s):  
Geographic Distribution ◽  
Case Control ◽  
Retrospective Data ◽  
Case Control Studies ◽  
Selection Of

scholarly journals Association of Helicobacter pylori Infection with the Risk of Metabolic Syndrome and Insulin Resistance: An Updated Systematic Review and Meta-Analysis

2021 ◽  
Author(s):  
Mobin Azami ◽  
Hamid Reza Baradaran ◽  
Parisa Kohnepoushi ◽  
Lotfolah Saed ◽  
Asra Moradkhani ◽  
...  
Keyword(s):  
Systematic Review ◽  
Insulin Resistance ◽  
Metabolic Syndrome ◽  
Helicobacter Pylori ◽  
Cohort Studies ◽  
Odds Ratio ◽  
Meta Analysis ◽  
Case Control ◽  
Case Control Studies ◽  
H Pylori

Abstract Background Conflicting results of recent studies on the association between Helicobacter pylori (H. pylori) infection and the risk of insulin resistance and metabolic syndrome explored the need for updated meta-analysis on this issue. Therefore, this systematic review aimed to estimate the pooled effect of H. pylori infection on the risk of insulin resistance and metabolic syndrome. Methods To identify case-control studies and cohort studies evaluating the association of H. pylori infection with insulin resistance and metabolic syndrome, a comprehensive literature search was performed from international databases including Medline (PubMed), Web of Sciences, Scopus, EMBASE, and CINHAL from January 1990 until January 2021. We used odds ratio with its 95% confidence interval (95%CI) to quantify the effect of case-control studies and risk ratio with its 95%CI for the effect of cohort studies. Results 22 studies with 206911 participants were included for meta-analysis. The pooled estimate of odds ratio between H. pylori infection and metabolic syndrome in case-control studies was 1.19 (95%CI: 1.05, 1.35; I2 = 0%), and in cohort studies, the pooled risk ratio was 1.31 (95%CI: 1.13, 1.51; I2 = 0%). Besides, case-control studies showed the pooled odds ratio of 1.54 (95%CI: 1.19, 1.98; I2 = 6.88%) for the association between H. pylori infection and insulin resistance. Conclusion A positive association was found between H. pylori infection and insulin resistance as well as metabolic syndrome, so planning to eliminate or eradicate H. pylori infection could be an effective solution to improve metabolic syndrome or insulin resistance, and vice versa.

Abstract 12672: Post-Implantation Hematoma Increases Risk of Cardiac Implantable Electronic Device Infection: A Systematic Review and Meta-analysis

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Jakrin Kewcharoen ◽  
Chanavuth Kanitsoraphan ◽  
Sittinun Thangjui ◽  
Thiratest Leesutipornchai ◽  
Leenhapong Navaravong
Keyword(s):  
Systematic Review ◽  
Cohort Studies ◽  
Electronic Device ◽  
Meta Analysis ◽  
Case Control ◽  
Cardiac Implantable Electronic Device ◽  
Case Control Studies ◽  
Randomized Controlled ◽  
Device Infection ◽  
Post Implantation

Introduction: Several studies have shown inconsistent relationship between post-implantation hematoma (PH) and cardiac implantable electronic device (CIED) infection. In this study, we performed a systematic review and meta-analysis to explore the effect of PH and the risk of CIED infection. Hypothesis: PH increases the risk of CIED infection. Methods: We searched the databases of MEDLINE and EMBASE from inception to March 2020. Included studies were cohort studies, case-control studies, cross-sectional studies and randomized controlled trials that reported incidence of PH and CIED infection during the follow-up period. CIED infection was defined as either a device-related local or systemic infection. Data from each study were combined using the random-effects, generic inverse variance method of Der Simonian and Laird to calculate odds ratios (OR) and 95% confidence intervals (CI). Results: Fourteen studies from 2006 to 2018 were included, involving a total of 28,319 participants. There were 6 cohort studies, 7 case-control studies and 1 randomized controlled trial. In random-effect model, we found that PH significantly increases the risk of overall CIED infection (OR = 6.30, 95%CI: 3.87-10.24, I2=49.3%) (Figure 1). There was no publication bias observed in the funnel plot as well as no small-study effect observed in Egger’s test. Conclusions: Our meta-analysis demonstrated that PH significantly increases the risk of CIED infection. Precaution should be taken to during device implantation to reduce PH and subsequent CIED infection.

scholarly journals Pregnancy and fertility-related adverse outcomes associated with Chlamydia trachomatis infection: a global systematic review and meta-analysis

2019 ◽  
Vol 96 (5) ◽  
pp. 322-329 ◽  
Author(s):  
Weiming Tang ◽  
Jessica Mao ◽  
Katherine T Li ◽  
Jennifer S Walker ◽  
Roger Chou ◽  
...  
Keyword(s):  
Cohort Studies ◽  
Risk Ratio ◽  
Low Income ◽  
Case Control ◽  
High Income ◽  
Adverse Outcomes ◽  
Chlamydia Infection ◽  
Case Control Studies ◽  
Middle Income ◽  
Middle Income Countries

BackgroundGenital chlamydia infection in women is often asymptomatic, but may result in adverse outcomes before and during pregnancy. The purpose of this study was to examine the strength of the relationships between chlamydia infection and different reproductive health outcomes and to assess the certainty of the evidence.MethodsThis review was registered and followed the Cochrane guidelines. We searched three databases to quantitatively examine adverse outcomes associated with chlamydia infection. We included pregnancy and fertility-related outcomes. We performed meta-analyses on different study designs for various adverse outcomes using unadjusted and adjusted analyses.ResultsWe identified 4730 unique citations and included 107 studies reporting 12 pregnancy and fertility-related outcomes. Sixty-eight studies were conducted in high-income countries, 37 studies were conducted in low-income or middle-income countries, and 2 studies were conducted in both high-income and low-income countries. Chlamydia infection was positively associated with almost all of the 12 included pregnancy and fertility-related adverse outcomes in unadjusted analyses, including stillbirth (OR=5.05, 95% CI 2.95 to 8.65 for case–control studies and risk ratio=1.28, 95% CI 1.09 to 1.51 for cohort studies) and spontaneous abortion (OR=1.30, 95% CI 1.14 to 1.49 for case–control studies and risk ratio=1.47, 95% CI 1.16 to 1.85 for cohort studies). However, there were biases in the design and conduct of individual studies, affecting the certainty of the overall body of evidence. The risk of adverse outcomes associated with chlamydia is higher in low-income and middle-income countries compared with high-income countries.ConclusionChlamydia is associated with an increased risk of several pregnancy and fertility-related adverse outcomes in unadjusted analyses, especially in low-income and middle-income countries. Further research on how to prevent the sequelae of chlamydia in pregnant women is needed.Trial registration numberCRD42017056818.

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