Association Between Vitamin D Deficiency and the Development of Complex Regional Pain Syndrome: A Retrospective Case-Control Study

Vitamin D deficiency has been suggested as a potential contributing factor in the development of Complex Regional Pain Syndrome (CRPS). This study aimed to investigate the association between serum vitamin D levels and CRPS using a retrospective case-control design. The study included 306 individuals divided into three groups: CRPS patients (n=102), fracture patients without CRPS (n=102), and healthy controls (n=102). Only patients whose vitamin D levels were measured during June, July, or August were included to minimize seasonal variation. Mean serum vitamin D levels were significantly lower in the CRPS group (10.2 ng/mL) compared to the fracture group (20.4 ng/mL) and control group (26.3 ng/mL) (p<0.001). The prevalence of vitamin D deficiency was highest in the CRPS group, followed by the fracture group, and lowest in the control group. Binary logistic regression analysis confirmed that vitamin D deficiency was independently associated with the presence of CRPS (OR: 14.57, 95% CI: 5.48-38.73, p<0.001), while age and sex were not significant predictors. No significant correlation was observed between serum vitamin D levels and other biochemical parameters. Vitamin D deficiency was more frequently observed in patients with CRPS than in fracture patients and healthy controls. These findings suggest an association between low vitamin D levels and the presence of CRPS. Further prospective studies are warranted.