• Written By: Fiona E. Costello, MD, FRCP

    This prospective, open-label study assessed the tolerability of high-dose oral vitamin D and its impact on biochemical, immunologic and clinical outcomes in patients with multiple sclerosis (MS).

    The study's researchers randomized 49 MS patients to treatment or control groups. Subjects in the 52-week-long trial were matched for demographic and disease characteristics. Treatment patients received escalating vitamin D doses up to 40,000 IU/day over 28 weeks to raise serum 25-hydroxyvitamin D [25(OH)D] rapidly and assess tolerability, followed by 10,000 IU/day for 12 weeks and further downtitrated to 0 IU/day. Throughout the trial, 1,200 mg/day calcium was given. Primary endpoints were mean change in serum calcium at each vitamin D dose and a comparison of serum calcium between groups. Secondary endpoints included 25(OH)D and other biochemical measures, immunologic biomarkers, relapse events and Expanded Disability Status Scale (EDSS) score.

    The authors found that all calcium-related measures within and between groups were normal. Despite a mean peak 25(OH)D of 413nmol/L, no significant adverse events occurred. Although there may have been confounding variables in clinical outcomes, treatment group patients appeared to have fewer relapse events and a persistent reduction in T-cell proliferation compared to controls.

    The authors conclude that it is safe for MS patients to take high-dose vitamin D of approximately 10,000 IU/day, and there is some evidence of immunomodulatory effects.