Multiple Sclerosis and health outcomes: an umbrella review of systematic reviews and meta-analyses

Abstract Purpose The previous analysis of systematic reviews and meta-analyses have illustrated that multiple sclerosis (MS) is correlated with multiple health outcomes. We designed an umbrella review to evaluate the breadth, validity and presence of biases of the associations of MS with diverse health outcomes. Methods We searched three databases (PubMed, We of Science and Embase) to recalculate the summary effect sizes, 95%CI, heterogeneity and small-study effects in the included meta-analyses. For each meta-analysis, we assessed the quality with AMSTAR2 and graded the epidemiologic evidence. Results A total of 28 articles comprising 84 unique meta-analyses were included in this study. Among the 84 unique outcomes, 52 unique outcomes had significant associations (p < 0.05). Only 6 outcomes (inflammatory bowel disease (IBD), ulcerative colitis (UC), crohn’s disease (CD), atrial fibrillation, herpes simplex virus type 2-IgG, hypothyroidism) showed high quality of epidemiological evidence. The remaining 46 outcomes were assessed to moderate or weak quality of evidence. Conclusion In our umbrella review, MS seems to increase the risk of IBD, UC, CD, herpes simplex virus type 2-IgG and hypothyroidism while decrease the risk of atrial fibrillation, with high epidemiological evidence. In order to verify our results, more prospective observational studies are needed.