Abstract
Multiple sclerosis (MS) is thought to arise due to an interplay of genetic and environmental risk factors. Vitamin D, besides maintaining bone health and calcium metabolism, is thought to play an immunomodulatory role in the central nervous system. Studies have shown that patients with the highest level of Vitamin D (99-152 nmol/l) had a significantly lower risk of MS than the subgroup with the lowest levels (15-63 nmol/l). Furthermore, populations having a high oral intake of vitamin D had a decreased risk of MS. Hypovitaminosis D is one of the environmental risk factors for MS based on numerous physiological, experimental and epidemiologic data, which can be corrected to provide an effective therapeutic option for this debilitating disease.