Evaluating the Association of Serum 25-Hydroxyvitamin D, Osteocalcin, Periostin, and Estradiol Levels With Hip Fracture Type and Severity in Patients Attending a Tertiary Care Center.

Background and objective 25-Hydroxyvitamin D (25(OH)D) status and bone turnover markers are considered important determinants of bone quality and are associated with the risk of hip fractures. However, the exact relationship between 25(OH)D, bone turnover markers, and the type and severity of hip fractures remains unclear. Hence, this study aimed to investigate the relationship between serum vitamin D levels and selected bone turnover biomarkers among patients with hip fractures. Methods According to the inclusion and exclusion criteria, a total of 70 patients with hip fractures were enrolled in this prospective study conducted between July 2025 and June 2026. The hip fracture patients were classified into intracapsular (IC) and extracapsular (EC) fracture groups. Serum concentrations of 25(OH)D, osteocalcin, periostin, and estradiol (E2) were measured using commercially available enzyme-linked immunosorbent assay (ELISA) kits from Elabscience (Houston, TX). Results The serum levels of 25(OH)D and E2 were significantly lower in patients with EC fractures than in those with IC fractures. In contrast, osteocalcin and periostin levels were significantly higher in the EC group than in the IC group. A statistically significant positive correlation (p < 0.05) was observed between serum osteocalcin and 25(OH)D levels and Singh index grades I-II and III-IV. Conversely, a statistically significant negative correlation (p < 0.05) was observed between serum periostin and E2 levels and Singh index grades I-II and III-IV. However, no statistically significant correlation was observed for Singh index grades V-VI. Conclusions In both the EC and IC fracture groups, serum 25(OH)D levels were significantly associated with Singh index grades I-II and III-IV. Lower serum levels of 25(OH)D and E2 and higher levels of osteocalcin and periostin were observed in patients with EC fractures compared with those with IC fractures. Further studies are warranted to improve our understanding of the roles of vitamin D and other bone turnover markers in orthopedic healthcare.