Vitamin D deficiency has been linked to a higher risk of multiple sclerosis (MS) and disease progression. However, the efficacy of vitamin D₃ as an adjuvant therapy for MS remains a controversial topic.

PubMed, Embase, and Cochrane Library were searched for trials published until December 18th, 2022. Authors independently selected randomized controlled trials involving patients with MS, with an intervention group receiving high dose (≥1000 IU/day) cholecalciferol and reporting clinical or radiological outcomes. Authors independently extracted data and assessed the risk of bias using a standardized, pilot-tested form. The meta-analysis was conducted using RStudio for EDSS at the last follow-up, ARR, and new T2 lesion count.

The findings of this meta-analysis strengthen current evidence that vitamin D₃ supplementation has no significant impact on clinical outcomes in patients with MS. However, the non-significant reduction of new T2 lesions could precede long-term clinical benefits and should be validated in additional studies.