Objective The association between mutations in the serotonin transporter gene-linked polymorphic region (5-HTTLPR) and irritable bowel syndrome (IBS) differs between populations. This meta-analysis was designed to assess the relationship between 5-HTTLPR polymorphisms and IBS in a Chinese population. Methods Relevant published studies from PubMed, Embase, Web of Science, the Cochrane Library, and China National Knowledge Infrastructure databases were accessed prior to May 2018. Odds ratios (ORs) with 95% confidence intervals (CIs) were pooled using STATA software. Results A total of 754 IBS cases and 578 healthy controls in six studies were included in this meta-analysis. Significant results were obtained between 5-HTTLPR polymorphisms and IBS risk among studies with the genotype distribution of controls in Hardy–Weinberg equilibrium (L vs. S, OR = 1.41, 95% CI: 1.11–1.79; LL vs. SS, OR = 2.17, 95% CI: 1.16–4.08; LL vs. LS + SS, OR = 2.29, 95% CI: 1.25–4.20). In subgroup analyses, 5-HTTLPR polymorphisms were significantly associated with increased IBS-C risk in China; however, no risk was observed for IBS-D and IBS-M. Conclusion This meta-analysis clearly indicates that 5-HTTLPR polymorphisms are associated with an increased risk of IBS in the Chinese population, especially IBS-C.
Meta-analysis: a functional polymorphism in the gene encoding for activity of the serotonin transporter protein is not associated with the irritable bowel syndrome