Evaluation of Vitamin D level in patients with juvenile idiopathic arthritis and its relation to disease activity and disease subtypes

BACKGROUND: Juvenile idiopathic arthritis (JIA) is the most common chronic arthritis in children. Vitamin D is an essential hormone in altering calcium homeostasis and modulating bone health. Its deficiency can result in rickets in children. Observationally, low Vitamin D levels have been associated with increased incidence and disease activity of many autoimmune disorders. AIM OF THE WORK: The aim of this study was to evaluate Vitamin D levels in patients with JIA and to detect its relation to disease activity and the disease subtypes. MATERIALS AND METHODS: This study included 20 patients with JIA and 20 controls. The patients were diagnosed as JIA according to the criteria of classification of the International League of Associations for Rheumatology. Serum 25-hydroxy Vitamin D3 level was assessed. The results were correlated with JIA disease duration, disease activity, and bone mineral density (BMD). BMD was measured by dual-energy X-ray absorptiometry (DEXA) of the lumbar spine using the Z -score. Disease activity was evaluated by Juvenile Arthritis Disease Activity Score-27. RESULTS: There was a significant difference between patients and control regarding serum Vitamin D level and DEXA Z -score ( P < 0.05). There was a negative correlation between serum Vitamin D level and disease activity ( P < 0.05). There was no significant difference between JIA subtypes as regards Vitamin D levels ( P = 0.129). CONCLUSIONS: Serum Vitamin D level was lower in patients with JIA disease, especially in patients with active disease and in patients treated with methotrexate. However, Vitamin D concentrations have no correlations with JIA subtypes.