Effects of Adjunct Low-Dose Vitamin D on Relapsing-Remitting Multiple Sclerosis Progression: Preliminary Findings of a Randomized Placebo-Controlled Trial

Abstract

The aim of this preliminary study was to evaluate the effect of low-dose oral vitamin D in combination with current disease-modifying therapy on the prevention of progression of relapsing-remitting multiple sclerosis (RRMS). A phase II double-blind placebo-controlled randomized clinical trial conducted between October 2007 and October 2008 included 50 patients with confirmed RRMS aged 25 to 57 years and normal serum 25-hydroxyvitamin D. They were randomly allocated to receive 12 months of treatment with either escalating calcitriol doses up to 0.5 μg/day or placebo combined with disease-modifying therapy. Response to treatment was assessed at eight-week intervals. In both groups, the mean relapse rate decreased significantly ( P < 0.001 ). In the 25 patients treated with placebo, the mean (SD) Expanded Disability Status Scale (EDSS) increased from 1.70 (1.21) at baseline to 1.94 (1.41) at the end of study period ( P < 0.01 ). Average EDSS and relapse rate at the end of trial did not differ between groups. Adding low-dose vitamin D to routine disease-modifying therapy had no significant effect on the EDSS score or relapse rate. A larger phase III multicenter study of vitamin D in RRMS is warranted to more assess the efficacy of this intervention.