Low levels of vitamin D significantly increase the risk of developing multiple sclerosis (MS), according to a study led by Dr. Brent Richards of the Lady Davis Institute at the Jewish General Hospital, and published in PLOS Medicine. This finding, the result of a sophisticated Mendelian randomization analysis, confirms a long-standing hypothesis that low vitamin D is strongly associated with an increased susceptibility to MS. This connection is independent of other factors associated with low vitamin D levels, such as obesity.