Fragility fractures are a major public health issue with substantial socioeconomic cost. Vitamin-D deficiency and increased bone turnover are associated with higher rates of bone loss and an increased risk of fracture. We hypothesized that patients with a distal radial fracture would have lower levels of 25-hydroxyvitamin D (25[OH]D) and increased levels of serum bone turnover markers than controls without a fracture.
Postmenopausal women with a recent distal radial fracture (fracture group, n = 105) were prospectively recruited and were compared with individuals without a fracture (control group, n = 150). Outcome variables included serum levels of 25(OH)D and markers of bone formation, including N-terminal extension propeptide of type-I collagen (P1NP), parathyroid hormone (PTH), bone-specific alkaline phosphatase (BSAP), and osteocalcin, as well as a marker of resorption (C-terminal telopeptide of type-I collagen [CTX-1]). Bone mineral density was measured with dual x-ray absorptiometry.
The fracture group was slightly older than the control group (mean and standard deviation [SD], 66.8 ± 10.8 years versus 63.3 ± 9.0 years, p = 0.008), had a lower body mass index (26.4 ± 5.9 kg/m2 versus 28.0 ± 6.2 kg/m2, p = 0.05), and more commonly had had a prior fracture (52% versus 31%, p < 0.001). Bone mineral density at the hip was lower in the fracture group than in the control group (0.831 ± 0.130 g/cm2 versus 0.917 ± 0.139 g/cm2, p < 0.001). The mean 25(OH)D levels were similar in the fracture and control groups (44.4 ± 14.6 ng/mL versus 41.3 ± 14.5 ng/mL, p = 0.08). Levels of serum markers of bone formation were significantly higher in the fracture group than in the control group (P1NP: 70.4 ± 33.2 ng/mL versus 53.2 ± 25.6 ng/mL, p < 0.001; osteocalcin: 22.3 ± 9.9 ng/mL versus 20.2 ± 9.2 ng/mL, p = 0.017). Levels of BSAP, PTH, and CTX-1 were similar in the two groups. Multivariable logistic regression showed independent associations between a distal radial fracture and low total hip bone mineral density (odds ratio [OR] = 2.02 for each decrease of 1 SD, 95% confidence interval [CI] = 1.38 to 3.01, p < 0.001) and a high P1NP level (OR = 2.17 for each 1-SD increase, 95% CI = 1.52 to 3.06, p < 0.001).
In this cohort, 25(OH)D levels were not associated with distal radial fracture and do not appear to affect the risk assessment for distal radial fracture in postmenopausal women. Patients with a distal radial fracture, however, had increased bone turnover as evidenced by high P1NP and osteocalcin levels. Women with both a high P1NP level and low bone mineral density were at particularly high risk for fracture.
Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
1Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Stoneman 10, Boston, MA 02215
2Departments of Anesthesia and Surgery, Children’s Hospital, 300 Longwood Avenue, Boston MA 02115
3Department of Orthopaedic Surgery, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030