Can vitamin D3 supplementation prevent bone loss in persons with MS?

Abstract

In persons with Multiple sclerosis (MS) low bone mineral density (BMD) is more prevalent when compared with healthy controls and MS may be a possible cause of secondary osteoporosis. BMD is primarily determined by genetic and hormonal factors, body mass index, physical activity and intake of calcium and vitamin D. Vitamin D level at 50 nmol/L or higher is classified as sufficient, however, optimal vitamin D level for bone health is according to many experts at least 75 nmol/L. In this 96 week randomized controlled clinical trial, we aimed to asses whether a weekly dose of 20,000 IU vitamin D3 could prevent bone loss in fully ambulatory persons with MS age 18-50 years. 71 persons with MS where randomized to receive either a weekly dose of 20,000 IU vitamin D3 or placebo. Half of the study participants had sufficient winter vitamin D levels (50 nmol/l) at study start and the level was strongly predicted by sun exposure through sun vacation or solarium and by vitamin D intake. All participants in the vitamin D group achieved sufficient winter vitamin D levels and levels of 75 nmol/L or higher were achieved by 91% of the participants. BMD was lower than expected in 25% of the participants at screening and BMD at the hip decreased by 1% in the whole study population. There was no significant difference between the groups. Several studies have shown that in persons with MS, BMD decreases as disability increasingly limits physical activity and progressing physical handicap also increases the risk of falls and fractures. Even though this small study could not prove any effect of vitamin D supplementation on BMD loss, intake of vitamin D is an important factor in preventing osteoporosis. In order to achieve adequate vitamin D levels, MS patients who have no vitamin D efficient sun exposure and low dietary vitamin D intake during the winter months should take vitamin D supplements.