High dose vitamin D supplementation does not affect biochemical bone markers in multiple sclerosis – a randomized controlled trial

Trygve Holmøy, Jonas Christoffer Lindstrøm, Erik Fink Eriksen, Linn Hofsøy Steffensen, Margitta T. Kampman

People with multiple sclerosis have high risk of osteoporosis and fractures. A poor vitamin D status is a risk factor for MS, and vitamin D supplementation has been recommended both to prevent MS progression and to maintain bone health. We assessed the effect of 20,000 IU vitamin D3 weekly compared to placebo on biochemical markers of bone metabolism in 68 persons with relapsing remitting multiple sclerosis. Serum levels of 25-hydroxyvitamin D more than doubled in the vitamin D group, and parathyroid hormone decreased in the vitamin D group compared to the placebo group at week 48 and week 96. There was however no effect on bone formation as measured by procollagen type I N propeptide (PINP), or on bone resorption as measured by C-terminal cross-linking telopeptide of type I collagen (CTX1). Neither PINP nor CTX1 predicted bone loss from baseline to week 96. These findings corroborate the previously reported lack of effect of weekly high dose vitamin D supplementation on bone mass density in the same patients, and suggest that such vitamin D supplementation does not prevent bone loss in persons with MS who are not vitamin D deficient. The trial was registered at ClinicalTrials.gov on April 4 2008, registration number NCT00785473 .