Associations between Gene Polymorphisms in Pro-inflammatory Cytokines and the Risk of Inflammatory Bowel Disease: A Meta-analysis

The relationships between polymorphisms in pro-inflammatory cytokines and the risk of inflammatory bowel disease (IBD) remain discrepant. Therefore, the authors conducted a meta-analysis to robustly explore relationships between polymorphisms in pro-inflammatory cytokines and the risk of IBD by integrating the results of previous works. Medline, Embase, Wanfang, VIP and CNKI were searched throughly for eligible studies, and 35 genetic association studies were finally included in this meta-analysis. We noticed that genotypic frequencies of <i>IL-1B</i> rs1143627, <i>IL-6</i> rs1800795 and <i>IL-8</i> rs4073 polymorphisms among cases with IBD and population-based controls differed significantly. Moreover, we found that genotypic frequencies of <i>IL-1B</i> rs1143627 and <i>IL-6</i> rs1800795 polymorphisms among cases with IBD and population-based controls of Caucasian origin differed significantly, whereas genotypic frequency of <i>IL-8</i> rs4073 and <i>IL-18</i> rs187238 polymorphisms among cases with IBD and population-based controls of Asian origin also differed significantly. Furthermore, we also noticed that genotypic frequency of <i>IL-18</i> rs187238 polymorphism among cases with Crohn’s disease (CD) and population-based controls differed significantly. In conclusion, this meta-analysis demonstrated that <i>IL-1B</i> rs1143627 and <i>IL-6</i> rs1800795 polymorphisms were significantly associated with the risk of IBD in overall population and Caucasians. Moreover, <i>IL-8</i> rs4073 polymorphism was significantly associated with the risk of IBD in overall population and Asians. In addition, we also noticed that <i>IL-18</i> rs187238 polymorphism was significantly associated with the risk of CD, and <i>IL-18</i> rs1946518 polymorphism was significantly associated with the risk of IBD in Asians.