Abstract
BACKGROUND: Measurement of bone mineral density by dual x-ray absorptiometry combined with clinical risk factors is currently the gold standard in diagnosing osteoporosis. Advanced imaging has shown that older patients with fragility fractures have poor bone microarchitecture, often independent of low bone mineral density. We hypothesized that premenopausal women with a fracture of the distal end of the radius have similar bone mineral density but altered bone microarchitecture compared with control subjects without a fracture. METHODS: Forty premenopausal women with a recent distal radial fracture were prospectively recruited and matched with eighty control subjects without a fracture. Primary outcome variables included trabecular and cortical microarchitecture at the distal end of the radius and tibia by high-resolution peripheral quantitative computed tomography. Bone mineral density at the wrist, hip, and lumbar spine was also measured by dual x-ray absorptiometry. RESULTS: The fracture and control groups did not differ with regard to age, race, or body mass index. Bone mineral density was similar at the femoral neck, lumbar spine, and distal one-third of the radius, but tended to be lower in the fracture group at the hip and ultradistal part of the radius (p = 0.06). Trabecular microarchitecture was deteriorated in the fracture group compared with the control group at both the distal end of the radius and distal end of the tibia. At the distal end of the radius, the fracture group had lower total density and lower trabecular density, number, and thickness compared with the control group (-6% to -14%; p < 0.05 for all). At the distal end of the tibia, total density, trabecular density, trabecular thickness, and cortical thickness were lower in the fracture group than in the control group (-7% to -14%; p < 0.01). Conditional logistic regression showed that trabecular density, thickness, separation, and distribution of trabecular separation remained significantly associated with fracture after adjustment for age and ultradistal radial bone mineral density (adjusted odds ratios [OR]: 2.01 to 2.98; p < 0.05). At the tibia, total density, trabecular density, thickness, cortical area, and cortical thickness remained significantly associated with fracture after adjustment for age and femoral neck bone mineral density (adjusted OR:1.62 to 2.40; p < 0.05). CONCLUSIONS: Despite similar bone mineral density values by dual x-ray absorptiometry, premenopausal women with a distal radial fracture have significantly poorer bone microarchitecture at the distal end of the radius and tibia compared with control subjects without a fracture. Early identification of women with poor bone health offers opportunities for interventions aimed at preventing further deterioration and reducing fracture risk.