Last update:
23-Jan-2018

Research on the role of vitamin D in patients with autoimmune conditions has increased in the past decade. Juvenile idiopathic arthritis (JIA) is the most common chronic disease in childhood and adolescence, but its specific cause remains unknown. Only a few studies have focused on the link between vitamin D deficiency and JIA. The high prevalence of vitamin D deficiency observed in JIA is an important public health issue, as patients in this particularly vulnerable group are at risk of fractures and delayed growth. Interpretation of the current evidence is restricted by the absence of an agreed definition of vitamin D deficiency in patients with JIA. It is unclear whether accepted "normal" levels of vitamin D are sufficient for this population, and the lower limit of deficiency that may affect disease activity in these children has not yet been determined. High steroid use as the therapeutic regimen, and the underlying joint inflammation of JIA may be involved in the low serum concentrations of vitamin D observed in these patients. It has been shown that the hormonally active form of vitamin D, 1,25-dihydroxyvitamin D (1,25[OH₂]D) inhibits the secretion of T leukocytes that appear to play an important role in the pathogenesis of autoimmune diseases such as JIA. Administration of high doses of vitamin D supplement is recommended in pediatric rheumatological diseases, as the immunomodulating and epigenetic benefits of 1,25(OH)₂D can only be achieved when high levels are present in tissues. Future research is required with large samples of patients with JIA, in order to adequately determine the mechanism of biological and hormonal effects of vitamin D on the autoimmune inflammatory process of JIA.

Key words: Bone mass, Dietary supplements, Juvenile idiopathic arthritis, Vitamin D.