Nutritional Status Is Associated with Bone Mineral Density, Vitamin D Levels, and Bone Turnover Markers in Patients with Proximal Femoral Fragility Fractures: A Retrospective Observational Study.

Background and Objectives: Malnutrition is common among older adults with fragility fractures and is linked to poor clinical outcomes in orthopedic surgery. However, the association between nutritional status and bone-related parameters, including bone mineral density (BMD) and bone turnover markers, remains inadequately characterized in this population. This study evaluated these associations in patients with proximal femoral fragility fractures. Materials and Methods: In total, 108 patients who underwent surgery for proximal femoral fragility fractures were retrospectively analyzed. Nutritional status was evaluated using the Geriatric Nutritional Risk Index (GNRI), Prognostic Nutritional Index (PNI), and Controlling Nutritional Status (CONUT) score. BMD was measured at the femoral neck of the proximal femur and the lumbar spine using dual-energy X-ray absorptiometry. Serum 25-hydroxyvitamin D (25[OH]D) and bone turnover markers, including total procollagen type I N-terminal propeptide and tartrate-resistant acid phosphatase 5b, were also evaluated. Correlation analyses, group comparisons, and multivariate linear regression analysis were performed to identify factors independently associated with femoral neck BMD. Results: GNRI and PNI were significantly positively correlated with femoral neck BMD (r = 0.48 and r = 0.26, respectively; both p < 0.01), while the CONUT score showed a significant negative correlation (r = -0.27, p < 0.01). Nutritional indices were not significantly correlated with lumbar spine BMD. Patients classified as malnourished by GNRI or PNI had significantly lower femoral neck BMD and serum 25(OH)D and higher bone turnover markers than well-nourished patients. Multivariate linear regression analysis revealed that GNRI, PNI, and CONUT score remained independently associated with femoral neck BMD after adjusting for age, sex, and body mass index. Conclusions: Nutritional status assessed by hematological indices was significantly associated with femoral neck BMD and bone metabolism markers in patients with proximal femoral fragility fractures. Findings underscore the importance of nutritional status in bone health and should be considered in the management of osteoporosis and fragility fractures.