Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 52 5 2014 05 15 400 405 EN Behzad Heidari Department of Internal Medicine, Rouhani Hospital, Babol, Iran AND Mobility Impairment Research Center, Babol University of Medical Sciences, Babol, Iran. Parham Heidari Avina Clinic, Tehran, Iran. Karim Hajian Tilaki Department of Social Medicine, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran. 2015 10 11 Arthralgia is a common presenting symptom of many rheumatic diseases. Vitamin D deficiency may lead to progression of skeletal symptoms to definite disease in susceptible subjects. This study was conducted to determine the relationship between vitamin D deficiency and unexplained arthralgia. Patients with arthralgia not related to a definite clinical condition were selected prospectively among subjects presented to a rheumatology clinic. Serum 25-hydroxyvitamin D (25-OHD) was measured by ELISA method and levels less than 20 ng/ml were considered as deficient levels. Serum 25-OHD levels and proportion of 25-OHD deficiency was compared in patients versus control. The association of serum 25-OHD and arthralgia was assessed by calculation of odds ratio (OR) using regression analysis. 167 patients with mean age of 38 ± 13.3 and 283 controls with mean age of 42.6±14.37 years (P=0.001) were studied. In patients mean serum 25-OHD was lower and proportion of deficiency was higher (P=0.001 for both).Serum 25-OHD deficiency was associated with 3.01 times increased risk of arthralgia (OR=3.01, 95% CI, 2.0- 4.25, P=0.001). After adjusment for age and sex, the risk of arthralgia remained significan at OR= 2.71(95%CI, 1.79-4.11,P=0.001).The odds of arthralgia decreased with increasing serum 25-OHD from OR=3.48 (95% CI,197-6,P=0.001) at serum <10 ng/ml to 3.39 (95%CI,1.93-5.98, P=0.001) at 10-19.9; and 1.31 (95%CI, 0.69-2.5, P=0.42) at 20-29.9 ng/ml. These findings indicate significant association of vitamin D deficiency and arthralgia. Regarding vitamin D deficiency as an environmental factor for development or progression of rheumatic diseases, this study justifies identification and correction of vitamin D deficiency in patients with arthralgia. https://acta.tums.ac.ir/index.php/acta/article/view/4606 https://acta.tums.ac.ir/index.php/acta/article/download/4606/4431