A review of studies published in the Annals of Pharmacotherapy (Vol. 40, No. 6, pp. 1158-1161) looked at the possible role vitamin D may have in prevention or amelioration of MS symptoms. Upon searching Medline for articles published between 1970 and 2006 and related to MS and vitamin D,  the authors found a number of studies that found that vitamin D supplementation improved the symptoms of MS patients. Supplementation with vitamin D was associated with a 40% reduced risk of developing MS according to the results of a large, prospective, cohort study.

In the journal Multiple Sclerosis (2009; 15(1): 9-15), research was published involving 213 subjects; 103 with MS and 110 healthy controls. The study found that for women (not men), every 10 mmol/L increase in 25(OH) vitamin D decreased the odds of getting MS by 19%. The authors of the study concluded that higher levels of vitamin D decreased the incidence, as well as the severity of disability in MS. Another study published in the Journal of the American Medical Association (2006; 296(23): 2832-8)