Relationship between serum vitamin D level and severity of rheumatoid arthritis

Recent studies have suggested a relation between vitamin D serum level and autoimmune diseases including rheumatoid arthritis (RA). Also، vitamin D has an important role in regulating the immune system. The present study aimed at exploring the relation between serum level of vitamin D and severity of RA. The study group consisted of 153 RA patients not on vitamin D supplements who had referred to Qazvin Avicenna Hospital. Disease activity was assessed according to the disease activity score28 (DAS28). Serum levels of vitamin D and Erythrocyte Sedimentation Rate (ESR) were determined for all the participants. Vitamin D deficiency was found in 105 RA patients (68. 6%). Patients were divided into three groups of low، moderate and high disease activity according to DAS28 score with 86 (56. 2%)، 33 (21. 5%) and 34 (22. 2%) patients respectively. A significant negative correlation was found between serum level of vitamin D and disease severity according to DAS28. Similarly، a negative correlation was shown to exist between the patients'' pain intensity according to VAS score، and their ESR serum level (P<0. 05). Vitamin D deficiency was prevalent among patients with RA. Furthermore، there was a negative correlation between vitamin D and the disease severity.