Kamren Hall, Jessica Renteria, Elizabeth Fernandez, Janique Abrahams, Saajan Bhakta
Vitamin D supplementation does not consistently reduce relapse rates in adults with MS, although some studies report improvement in MRI activity. The overall certainty of evidence is limited by variation in study design, patient population, cohort size, and risk of bias. Current data does not support vitamin D as a disease-modifying therapy beyond correction of deficiency; further, larger, standardized trials are needed to clarify its clinical role.
INTRODUCTION: Literature evidence links vitamin D supplementation to clinical outcomes in multiple sclerosis (MS), yet no systematic review has focused specifically on relapse rate and MRI activity. Thus, this systematic review aimed to evaluate the effect of vitamin D supplementation on relapse rate and magnetic resonance imaging (MRI) disease activity in adults with clinically diagnosed MS.
METHODS: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. PubMed, Cochrane, EBSCO, and Web of Science were searched for studies discussing vitamin D supplementation in adults with diagnosed MS. Annualized relapse rate (ARR) and changes in MRI activity were the primary outcome measures. Non-randomized studies and randomized controlled trials were assessed for their risk of bias using the Cochrane ROBINS-I and RoB-2 tools, respectively.
RESULTS: Of 304 records identified, 127 duplicates were removed and 177 were screened, with 11 primary studies (14 reports) included after full-text review. Across studies, vitamin D supplementation did not suggest a reduced ARR with most randomized trials reporting no significant difference between groups. One trial using alfacalcidol provides evidence for a reduction in relapse risk, but this was not replicated. MRI outcomes were more variable, with several studies showing reductions in inflammatory lesion activity, while others found no significant effect. Overall, results were inconsistent, and due to heterogeneity in study design and reporting, findings were synthesized narratively without meta-analysis.
CONCLUSION: Vitamin D supplementation does not consistently reduce relapse rates in adults with MS, although some studies report improvement in MRI activity. The overall certainty of evidence is limited by variation in study design, patient population, cohort size, and risk of bias. Current data does not support vitamin D as a disease-modifying therapy beyond correction of deficiency; further, larger, standardized trials are needed to clarify its clinical role.