ABSTRACT
Rheumatoid arthritis [RA] is one of the most prevalent autoimmune diseases in the world. Some of the researches have suggested that the serum vitamin D level may relate to disease activity. The current study was designed to identify the correlation between serum vitamin D level and the disease activity index [DAI]. In this sectional study, 108 patients [diagnosed based on the American Committee of Rheumatology criteria] were enrolled. In all cases after determining the serum vitamin D level and ESR, complete joint examination were done. The normal range of vitamin D was 47.7-144 nm/lit. Then, the specified disease activity form [DAS-28] and visual analog scales [VAS] were filled out. The correlation between disease activity index, [based on VAS, tendered or swelled joints and ESR] and serum vitamin D was analyzed using Chi square, Mann Whitney and t-tests. Seventy nine [73.14%] out of 108 patients had normal serum vitamin D and 29 [26.86%] had low serum vitamin D level. The mean age of patients with normal and low serum vitamin D level were 52.22 +/- 11.6 and 48.48 +/- 12.51, respectively [P=0.075]. The mean DAI in normal and low vitamin D patients were 3.75 +/- 1.37 and 5.19 +/- 1.56, respectively [P=0.00]. The mean number of swollen joints in normal and low vitamin D patients was 1.24 +/- 1.39 and 3.65 +/- 3.3, respectively [P=0.001]. The mean number of tender joints in normal and low vitamin D patients were 6.84 +/- 4.41 and 9.44 +/- 3.62, respectively [P=0.042]. The mean ESR in normal and low vitamin D patients were 19.40 +/- 12.40 and 37.91 +/- 21.72, respectively [P=0.002]. Moreover, the mean VAS in normal and low vitamin D patients was 23.29 +/- 19.42 and 50.68 +/- 30.78, respectively [P=0.003]. The more active the RA, the less serum vitamin D level