In all parts of the world, MS is more common at latitudes that are farther from the equator and less common in areas closer to the equator. This latitude effect has been under investigation for many years. Previous studies have found evidence suggesting that higher lifetime exopsure to sunlight (through which the skin makes vitamin D) and higher blood levels of vitamin D may reduce a person’s risk of developing MS.
Researchers at the Australian National University, Canberra, recently published the results of the Ausimmune Study, a comprehensive look into the impact of higher levels of sun exposure and higher blood levels of vitamin D on MS risk.
Read more about the study and their findings here: http://nationalmssociety.org/news/news-detail/index.aspx?nid=4561