Vitamin D and Autoimmune Disease

During the past decade, important advances in the study of vitamin D have been made as vitamin D insufficiency is emerging as a clinical problem at a global level. In addition to its important role in skeletal development and maintenance, evidence is mounting that vitamin D produce beneficial effect on extraskeletal tissues. Recent evidence shows that vitamin D deficiencies contribute autoimmune diseases susceptibility and severity. This chapter will provide a systematic review of the importance of vitamin D in preexisting autoimmune diseases and whether its deficiency predispose patients to such disorders.