Imawana RA, et al. - This study was sought to test if this impact varied by inflammatory bowel disease (IBD) subtype—Crohn’s disease (CD) or ulcerative colitis (UC)—and geographic region: East Asia, Europe (non-Mediterranean), or Mediterranean region. Researchers conducted a database search up to July 2019 inclusive for all studies that compared H. pylori infection in IBD patients vs. non-IBD controls. The relationship between IBD and H. pylori was evaluated by applying relative risk (RR), and the impacts were combined across studies applying a mixed-effects meta-regression model, which included IBD subtype and geographic region as categorical moderator variables. The results of this study displayed that the protective impact of H. pylori on IBD varied by both subtype (more protection against CD vs. UC) and region (East Asia more protected than Mediterranean regions). Variation due to these impacts could serve insight into IBD etiology.