Association between SERT insertion/deletion polymorphism and the risk of irritable bowel syndrome: A meta-analysis based on 7039 subjects

Purpose: We performed this study to better assess the relationship between serotonin transporter (SEAT) insertion/deletion polymorphism and the risk of irritable bowel syndrome (IBS). Methods: Eligible studies were searched in PubMed, Medline, Embase and CNKI. A total of 27 studies with 7039 participants were analyzed. Results: Significant association with the risk of IBS was detected for the SERT insertion/deletion polymorphism in additive comparison (p < 0.0001). Further subgroup analyses according to ethnicity of participants revealed that the SERT insertion/deletion polymorphism was significantly associated with the risk of IBS in Asians (dominant model: p = 0.001; recessive model: p = 0.0003; allele model: p = 0.001) and Caucasians (dominant model: p = 0.04; additive model: p < 0.0001). When we stratified available data according to type of disease, we found that the SERT insertion/deletion polymorphism was significantly correlated with the risk of constipation predominant IBS (IBS-C) in recessive comparison (p = 0.04). However, no positive results were detected in the diarrhea predominant IBS (IBS-D) and mixture of diarrhea and constipation IBS (IBS-M) subgroups. Conclusions: Our findings indicated that the SERT insertion/deletion polymorphism may serve as a genetic biomarker of IBS in Asians and Caucasians.