Clinical Characteristics and Serum Vitamin D Levels in Patients with MRONJ Associated with Antiresorptive Therapy: A...

Background and Objectives: Medication-related osteonecrosis of the jaw (MRONJ) is a severe complication associated with antiresorptive therapy. Although several local and systemic risk factors have been documented, the role of metabolic biomarkers and their relationship with clinical characteristics remains insufficiently investigated. The aim of the present study was to evaluate the relationships between antiresorptive therapy, serum vitamin D levels, demographic characteristics, and lesion location in patients diagnosed with MRONJ. Materials and Methods: This retrospective study included 72 patients diagnosed with MRONJ, divided into three groups according to the antiresorptive therapy administered: zoledronic acid (n = 30), denosumab (n = 22), and oral bisphosphonates (n = 20). Clinical and demographic data, including age, sex, smoking status, serum vitamin D levels, number of extracted teeth, lesion location (mandibular versus maxillary), and associated comorbidities, were obtained from medical records. Statistical analysis was performed using Welch's ANOVA, Welch's t-test, chi-square, Fisher's exact, and Pearson and Spearman correlation analyses. Results: No significant differences in serum vitamin D levels were observed among the three antiresorptive therapy groups. However, patients with mandibular MRONJ had significantly lower serum vitamin D levels than those with maxillary involvement (p = 0.046). Lower serum vitamin D levels were independently associated with mandibular MRONJ after multivariable adjustment. Female sex and thyroid disease were more frequent in the oral bisphosphonate group. Additionally, patient age was moderately positively correlated with the number of extracted teeth (r = 0.440, p < 0.001). Conclusions: This retrospective study identified a possible association between lower serum vitamin D levels and mandibular MRONJ. Given the observational design of the study, these findings should be interpreted with caution and require confirmation in larger prospective studies.