Relationship Between Helicobacter Pylori Infection And Colorectal Cancer: A Meta-Analysis Of Observational Studies

Helicobacter pylori infection has been proposed to be associated with bowel cancers. The purpose of this meta-analysis was to evaluate the association between H. pylori infection and CRC. In this study, all case-control studies up to January, 2017 were identified by searching PubMed and Cochrane library. In absence of significant heterogeneity fixed-effects model (Mantel-Haenszel method) was used otherwise random effects (Der SimonianLaird method) model was used. Subgroup analysis was performed to assess the sources of heterogeneity (CRC subtype, geographic area, and study design type). 6 case-control studies, and 4 cross-sectional studies with a total of 16,857 participants and more than 3300 incident cases of CRC were included in our meta-analysis. In overall meta-analysis, pooled analysis of 10 observational studies imply that there is an increased risk of CRC in patients with history of H. pylori infection. But, pooling high quality studies showed that there was no significant association between H. pylori infection and risk of CRC. In subgroup analysis, association between H. pylori infection and CRC was observed only in cross-sectional studies but not in case-control studies. Both colon and rectal cancer did not show any significant association with H. pylori infection. Studies conducted in Asia showed a significant positive association of risk of CRC and H. pylori infection. Our meta-analysis suggests that there is no conclusive evidence to show the association between risk of CRC and H. pylori infection, and the heterogeneity present in the existing evidence which was neglected in many of the previous meta-analysis while deriving conclusions.