The Associations of Serum Vitamin D and Bone Turnover Markers with the Type and Severity of Hip Fractures in Older Women

Purpose: Vitamin D (25[OH]D) status and bone turnover markers (BTMs) are considered important determinants of bone quality, which is associated with the risk of hip fractures, including both femoral neck and intertrochanteric fractures, in older adults; however, the exact relationship of 25(OH)D and BTMs with the type and severity of hip fractures remains unclear and the present study aimed to identify any specific associations. Patients and Methods: According to the inclusion and exclusion criteria, 441 older female patients with hip fractures from 2015 to 2020 and 215 women without hip fractures were included in this cross-sectional study. According to Garden and AO/OTA classifications for femoral neck and intertrochanteric fractures, patients were divided into less severe (Garden I and Garden II; 31A1) and more severe (Garden III and Garden IV; 31A2 and 31A3) fracture groups. Levels of the serum osteoblast indicator, N-terminal/mid region (N-MID); the osteoclast indicator, beta-carboxy terminal telopeptide (beta-CTX); and 25(OH)D were analyzed. Results: For patients with less severe fractures, mean 25(OH)D levels were significantly higher than those with more severe fractures (17.67 vs 15.30 ng/mL, p = 0.006). Higher 25(OH)D levels were also observed in patients with less severe intertrochanteric fractures (p = 0.01). After adjustments for confounders, 25(OH)D remained a risk factor for patients with more severe fractures (p = 0.01), particularly those with intertrochanteric fractures (p = 0.011). No significant differences in BTMS were found between patients with less severe and more severe fractures. Conclusion: Levels of 25(OH)D were significantly associated with the severity of intertrochanteric, but not femoral neck, fractures. Neither 25(OH)D nor BTMs were associated with the type of hip fracture in older women. Separate consideration of intertrochanteric and femoral neck fractures may be appropriate when investigating the clinical association between 25(OH)D and the severity of hip fractures in older women.