[Vitamin D insufficiency--possible etiologic factor of autoimmune diseases]

The primary source of vitamin D in humans is sun exposure to the skin. The incidence of certain autoimmune diseases correlates positively with latitude. As vitamin D production increases with sun exposure, vitamin D insufficiency is hypothesised to influence the development of autoimmune diseases. In experimental animal and cellular studies in vitro 1.25-(OH)2-vitamin D reduces inflammation. This article discusses the role of vitamin D in inflammatory bowel disease, type 1 diabetes mellitus, multiple sclerosis, and rheumatoid arthritis.