The Multifaceted Effects of Vitamin D and Its Potential Contribution to Rheumatoid Arthritis

Vitamin D (VD) is known to have pleiotropic effects on various tissues and organs including those of the immune and musculoskeletal systems. VD deficiency has been suggested to trigger the onset of autoimmune diseases including rheumatoid arthritis (RA), although the significance of this finding remains controversial. Conversely, patients with RA often have VD deficiency, and it may modify the pathophysiology of the disorder. This review summarizes recent findings on the multiple roles of VD that may modulate the clinical course of RA. The possibility of administering VD as a therapeutic option for RA is also explored.