Abstract
<title>Abstract</title> <p>Objectives To evaluate associations of serum vitamin D status with cone-beam computed tomography (CBCT)-defined temporomandibular joint osteoarthritis (TMJ OA), structural severity, and pain intensity, and to explore its incremental predictive contribution. Materials and methods This retrospective study included 241 patients with TMJ arthralgia who underwent clinical assessment, CBCT imaging, serum 25-hydroxyvitamin D measurement, laboratory testing, and psychological assessment. Associations with TMJ OA presence, severity, and visual analog scale (VAS) pain intensity were examined using adjusted regression models. Exploratory prediction analyses used Elastic Net, XGBoost, and Shapley additive explanations. Results Patients with TMJ OA had lower vitamin D levels than those without TMJ OA (18.11 ± 8.95 vs. 25.11 ± 8.16 ng/mL; p < 0.001). Each 10-ng/mL increase was associated with lower adjusted odds of TMJ OA presence (OR 0.35; 95% CI 0.23–0.54) and greater structural severity (OR 0.28; 95% CI 0.18–0.43). Vitamin D deficiency was associated with higher VAS pain intensity (adjusted β 1.47; 95% CI 0.50–2.45). Adding vitamin D improved AUROC in Elastic Net (0.522 to 0.722; p = 0.023) and XGBoost (0.572 to 0.834; p = 0.001), and feature-importance analysis ranked vitamin D first. Conclusions Lower serum vitamin D status was associated with CBCT-defined TMJ OA, greater structural severity, and higher pain intensity. Clinical relevance Serum vitamin D may provide complementary systemic information in painful TMJ OA, although prospective and external validation is required.</p>