Association between nonspecific skeletal pain and vitamin D deficiency

Background: Deficiency of vitamin D has been reported in patients with many types of musculoskeletal pain. The present study was designed to determine the association between serum 25-hydroxyvitamin D [25-(OH)D] deficiency and nonspecific skeletal pain. Methods: A total of 276 patients with nonspecific skeletal pain at different regions of the skeletal system diagnosed as leg pain, widespread pain, arthralgia, rib pain, back pain and fibromyalgia were compared with 202 matched controls with regard to mean serum 25-(OH)D level and 25-(OH)D deficiency. Serum 25-(OH)D was measured by enzyme-linked immunosorbent assay method and levels < 20 ng/mL were considered as deficient. Nonparametric one-way analysis of variance, Kruskal Wallis and Wilcoxon tests were used for group comparisons. Multiple logistic regression analysis with calculation of adjusted odds ratio (OR) and 95% confidence interval (95% CI) were performed to determine associations. Results: In patients with nonspecific skeletal pain the mean 25-(OH)D was significantly lower (P = 0.0001) and the proportion of 25-(OH)D deficiency was significantly higher (63.4%vs. 36.1%, P = 0.0001) compared with controls. There was a significantly positive association between 25-(OH)D deficiency and skeletal pain (OR = 2.94, 95% CI = 1.01-4.3, P = 0.0001). The strength of association varied across the groups with strongest association observed with leg pain (OR = 7.4; 95% CI = 3.9-13.9, P = 0.0001) followed by arthralgia (OR = 3.9, 95% CI = 2.1-7.1, P = 0.0001) and widespread pain (OR = 2.8, 95% CI = 1.1-6.6, P = 0.020) but no association with back pain and fibromyalgia. There was a greater positive associations in women compared with men (OR = 2.1, 95% CI = 1.1-4.3, P = 0.001). Conclusion: The results of this study indicate a positive association of vitamin D deficiency with a variety of nonspecific bone pain, particularly in women. More studies with larger samples are required to confirm these findings. Increasing serum vitamin D to sufficient levels and longitudinal follow-up of patients may provide further evidence in relation to vitamin D deficiency and skeletal pain.