Association Between Helicobacter pylori Exposure and Decreased Odds of Eosinophilic Esophagitis—a Systematic Review and Meta-analysis

BACKGROUND & AIMS: Previous or current infection with Helicobacter pylori (exposure) has been reported to protect against eosinophilic esophagitis (EoE), perhaps due to H pylori-induced immunomodulation. However, findings vary. We performed a systematic review and meta-analysis of comparative studies to more clearly define the association between H pylori exposure and EoE. METHODS: We searched 4 large databases to identify comparative clinical studies that included sufficient detail to determine the odds or risk of EoE (primary outcome) or esophageal eosinophilia (secondary outcome) among individuals exposed to H pylori (exposed) vs individuals who were tested and found to be unexposed. Estimates were pooled using a random-effects model. Meta-regression and sensitivity analyses were planned a priori. Studies were evaluated for quality, risk of bias, publication bias, and heterogeneity. RESULTS: We analyzed 11 observational studies comprising data on 377,795 individuals worldwide. H pylori exposure vs non-exposure was associated with a 37% reduction in odds of EoE (odds ratio [OR], 0.63; 95% CI, 0.51–0.78) and a 38% reduction in odds of esophageal eosinophilia (OR, 0.62; 95% CI, 0.52–0.76). Fewer prospective studies found a significant association between H pylori exposure and EoE (P=.06) than retrospective studies. Effect estimates were not affected by study location, whether the studies were performed in pediatric or adult populations, time period (before vs after 2007), or prevalence of H pylori in the study population. CONCLUSIONS: In a comprehensive meta-analysis, we found evidence for a significant association between H pylori exposure and reduced odds of EoE. Studies are needed to determine the mechanisms of this association.