Abstract
Multiple sclerosis is primarily an inflammatory disorder of the brain and spinal cord in which focal lymphocytic infiltration leads to damage of myelin and axons. Both genetic and environmental factors are believed to play a part in the development of the disease. Latitude is significantly associated with the prevalence of multiple sclerosis, and inadequate serum concentrations of vitamin D due to less exposure to sunlight at higher latitudes has been proposed as an explanation. This review discusses the relationship between multiple sclerosis and vitamin D, and how vitamin D can modify the disease.