A significant association between infrequent summer outdoor activity and increased MS risk was found in Norway and in Italy. Converging evidence from different measures underlines the beneficial effect of sun exposure on MS risk.

http://www.ncbi.nlm.nih.gov/pubmed/24414538


Sun exposure and multiple sclerosis risk in Norwa... [Mult Scler. 2014] - PubMed - NCBI
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