The efficacy of vitamin D in multiple sclerosis: A meta-analysis

Abstract Background Multiple sclerosis (MS) is a chronic inflammatory demyelination disorder in the central nervous system (CNS) leading to a high level of neurological disability. The pathogenesis of MS remains largely unknown, which explains the lack of significant efficacy of therapy in MS. Vitamin D deficiency is widely considered to be an environmental risk factor for MS. Many studies investigating the therapeutic effects of vitamin D on MS have been applied. The objective of this systematic review and meta-analysis was to evaluate the effectiveness of vitamin D in MS patients. Methods To obtain a more comprehensive estimate of the efficacy of vitamin D on MS patients, we conducted a meta-analysis to determine the role of vitamin D in MS. The PubMed, EMBASE and Cochrane databases were searched in October 2017. Randomized, double-blind, placebo-controlled clinical trials recorded within the three main databases were considered. The analysis was conducted for two specific outcomes: Expanded Disability Status Scale (EDSS) score and annual relapse rate (ARR). Results Vitamin D 3 as add-on treatment had no significant therapeutic effect on MS according to EDSS score (mean difference -0.01 [95% CI -0.34 to 0.33]). The ARR was higher in the vitamin D group than in the placebo group (mean difference 0.05 [95% CI 0.01 to 0.1]). Conclusion Our findings suggest that vitamin D appeared to have no therapeutic effect on EDSS score or ARR in the patients with MS.