{"title":"Case–Control Studies","authors":"A. Soto, A. Cvetkovic-Vega","doi":"10.1002/9781119584254.ch7","DOIUrl":"https://doi.org/10.1002/9781119584254.ch7","url":null,"abstract":"Case-control studies are analytical observational epidemiological studies generally devoted to evaluate factors associated with infrequent diseases. Its hierarchy within the pyramid of evidence lies in an intermediate place between cross sectional and cohort studies. The measure of association used for these studies is the Odds Ratio. Some variants of this design, such as incident and nested case studies and nested case-control studies (within a cohort) can reduce the risk of selection bias. The basic concepts related to this type of studies are reviewed.","PeriodicalId":267632,"journal":{"name":"Biostatistics Decoded","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122444833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Meta‐analysis","authors":"Shiwan Hu","doi":"10.1002/9781119584254.ch18","DOIUrl":"https://doi.org/10.1002/9781119584254.ch18","url":null,"abstract":"Background: Number of studies have been performed to evaluate the relationship between the cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) gene variant rs5742909 polymorphism and cervical cancer risk, but the sample size was small and the results were conflicting. This meta-analysis was conducted to comprehensively evaluate the overall association. Methods: PubMed, Web of Science, Embase, China Biology Medical Literature database, China National Knowledge Infrastructure, WanFang, and Weipu databases were searched before July 31, 2018. The strength of associations was assessed using odds ratios (ORs) and 95% confidence intervals (CIs). All of the statistical analyses were conducted using Review Manager 5.3 and Stata 14.0. Results:Eleven studies involved 3899 cases and 4608 controls. Overall, significant association was observed between theCTLA-4 gene variant rs5742909 polymorphism and cervical cancer (T vs C: OR=1.40, 95% CI=1.12–1.76; TT vs CC: OR=2.22, 95% CI= 1.13–4.37; TT vs CT+CC: OR=1.96, 95% CI=1.03–3.74; TT+CT vs CC: OR=1.47, 95% CI=1.14–1.90). In subgroup analysis by ethnic group, a statistically significant association was observed in Asians (T vs C: OR=1.56, 95% CI=1.22–1.99), but not in Caucasians (T vs C: OR=1.19, 95% CI=0.87–1.62). The sensitivity analysis confirmed the reliability and stability of the metaanalysis. Conclusion: our meta-analysis supports that the CTLA-4 gene variant rs5742909 polymorphism might contribute to individual susceptibility to cervical cancer in Asians. Abbreviations: CI = confidence interval, CTLA-4 = cytotoxic T-lymphocyte associated antigen-4, HWE = Hardy–Weinberg equilibrium, NOS = Newcastle–Ottawa scale, OR = odds ratio, PCR = polymerase chain reaction, PCR-RFLP = polymerase chain reaction-restriction fragment length polymorphism, SNP = single nucleotide polymorphism.","PeriodicalId":267632,"journal":{"name":"Biostatistics Decoded","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131354001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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