Associations between cytokine gene polymorphisms and susceptibility to Helicobacter pylori infection and Helicobacter pylori related gastric cancer, peptic ulcer disease: A meta-analysis

OBJECTIVES: The aim of this study is to clarify the associations between IL-1B31C/T, IL-1B-511C/T, IL-8-251T/A gene polymorphisms and the risk of Helicobacter pylori (H. pylori) infection together with H. pylori-related gastric cancer (GC), peptic ulcer disease (PUD). METHODS: All eligible literature published up to July 2016 were identified by searching Pubmed, Embase, Web of Science and CNKI. Pooled odds ratio (OR) and 95% confidence interval (95% CI) were calculated using a fixed or random effects model. RESULTS: 29 case-control studies were eligible, and each of them may focus on more than one gene polymorphism. Ultimately, there were 21 studies (3159 cases and 2816 controls) for IL-1B-31C/T, 16 studies (2486 cases and 1989 controls) for IL-1B-511C/T polymorphisms, 9 studies (1963 cases and 1205 controls) for IL-8-251T/A polymorphisms. Overall, an increased risk of H. pylori infection was found for IL-1B-31C/T polymorphisms in total population [OR = 1.134, 95%CI = 1.008–1.275 for recessive model; OR = 1.145, 95%CI = 1.007–1.301 for TT vs CC model]. While, for IL-1B-511C/T and IL8-251T/A polymorphisms, no evidence indicated that they were associated with the risk of H. pylori infection in all genetic models. Furthermore, we found an increased risk of H. pylori-related GC with IL-1B-511C/T polymorphisms [OR = 1.784, 95%CI = 1.289–2.469 for recessive model; OR = 1.772, 95%CI = 1.210–2.594 for TT vs CC model] and IL8-251A/T polymorphisms [OR = 1.810, 95%CI = 1.229–2.667 for recessive model; OR = 1.717, 95%CI = 1.143–2.580 for TT vs AA model], an increased risk of H. pylori-related PUD with IL8-251T/A polymorphisms [OR = 1.364, 95%CI = 1.010–1.843 for recessive model; OR = 1.427, 95%CI = 1.039–1.959 for AA vs TT model]. CONCLUSIONS: IL-1B-31C/T gene polymorphisms might increase H. pylori infection risk. IL-1B-511-C/T and IL-8-251T/A gene polymorphisms might act as a risk factor to H. pylori-related diseases including GC or PUD