Alcohol consumption is associated with excessive risk of multiple sclerosis: a meta-analysis observational study

BACKGROUND: There have been inconsistent results regarding the association between alcohol intake and susceptibility to multiple sclerosis. OBJECTIVE: To assess the potential role of alcohol intake regarding the risk of multiple sclerosis by using a meta-analytic approach. DESIGN AND SETTING: Observational meta-analysis study conducted in a hospital in China. METHODS: The electronic databases of PubMed, EMBASE and the Cochrane library were systematically searched for eligible studies from their inception up to January 2020. The summary odds ratio (OR) with 95% confidence interval (CI) was applied to assess the association between alcohol intake and multiple sclerosis, using a random-effects model. RESULTS: One prospective cohort study and eight case-control studies involving a total of 211,396 subjects and 10,407 cases of multiple sclerosis were selected for the final meta-analysis. From the pooled data, no significant association between alcohol intake and multiple sclerosis risk was found (OR: 0.94; 95% CI: 0.73-1.22; P = 0.668), and this conclusion was judged to be robust. Subgroup analysis found that intake of beer was associated with an increased risk of multiple sclerosis (OR: 1.58; 95% CI: 1.12-2.23; P = 0.010). CONCLUSION: This study found that beer intake could cause an excess risk of multiple sclerosis. Further large-scale prospective studies should be conducted to verify this conclusion.