REPORT FROM THE AMERICAN ACADEMY OF NEUROLOGY (AAN) ANNUAL MEETING, PHILADELPHIA PA, APRIL 26-MAY 3, 2014 – For over 50 years, solar radiation and vitamin D have been implicated in the pathogenesis of MS (Acheson et al. Acta Psychiatr Scand Suppl 1960;35:132-147), in large part due to the latitude effect. However, the relevance of serum 25(OH)D levels and the virtues of vitamin D supplementation remain controversial.