Association between Helicobacter pylori infection and multiple sclerosis: A systematic review and meta-analysis

Aim: To investigate the association between Helicobacter pylori infection and multiple sclerosis. Methods: A comprehensive search of the databases including PubMed/MEDLINE and EMBASE was performed from their dates of inception to January 2016. Inclusion criteria were the observational studies in adult assessing the association between Helicobacter pylori infection and multiple sclerosis. The main outcome was the prevalence of Helicobacter pylori infection comparing between participants with multiple sclerosis and controls. The between-study heterogeneity of effect-size was quantified using the Q statistic and I-2. Results: The initial search yielded 103 articles. Seventeen articles underwent full-length review and data was extracted from six observational studies involving 1902 participants. There was a statistically significant lower odds Helicobacter pylori infection in multiple sclerosis with pooled odds ratio of 0.59 (95% CI: 0.37-0.94, P=0.03, I-2 = 71%). We conducted a univariate meta-regression analysis to assess potential source of heterogeneity. Age of patient and age of onset of multiple sclerosis were significant predictors of association between Helicobacter pylori infection and multiple sclerosis (beta-coefficient = -0.23, SE = 0.10. p = 0.02 and beta-coefficient = -0.34, SE = 0.17, p = 0.04, respectively). Conclusions: We demonstrate a significant lower prevalence of Helicobacter pylori infection in patients with multiple sclerosis. This pathogen might be a protective factor for developing multiple sclerosis. (C) 2016 Elsevier B.V. All rights reserved.