Vitamin D Deficiency and Rheumatoid Arthritis: Epidemiological, Immunological, Clinical and Therapeutic Aspects

Vitamin D displays an immunologic effect which can modulate function of Th17-related cytokines and thereby prevent perpetuation of inflammation in chronic disorders like rheumatoid arthritis (RA). This review aims to conduct a literature review to provide a summary of recent studies addressing the relationship between vitamin D deficiency and RA based on epidemiological, immunological and therapeutic aspects.

PubMed, Scopus and Google scholar were searched for relevant papers published between 2000-2018.

Low intake of vitamin D increases the risk of incident RA, and vitamin D deficiency has been shown to be inversely associated with RA activity in most of these studies. However, characteristics of RA and serum vitamin D status differ across the studies. The results of studies on the effect of supplemental vitamin D in RA vary, from no efficacy to significant improvement in disease activity, as well as quality of life. This should be attributed to variations in dosage of vitamin D, duration of treatment, baseline serum vitamin D in RA patients and characteristics of RA across diverse studies.

Current data indicate a therapeutic potential for vitamin D in RA. However, further studies are needed to identify an optimal and effective dosage, duration of treatment and patients who will get the best benefit from the treatment.