Cortical Bone Area Predicts Incident Fractures Independently of Areal Bone Mineral Density in Older Men.

Abstract

Areal bone mineral density (aBMD) measured using dual-energy X-ray absorptiometry (DXA) is used clinically to predict fracture but does not discriminate between trabecular and cortical bone assessment. This study aimed to investigate whether information on cortical and trabecular bone predict fracture risk independently of aBMD and clinical risk factors. Cortical area, bone mass, porosity, and trabecular bone volume fraction (BVTV) were measured at the tibia using high-resolution peripheral quantitative computed tomography (HR-pQCT) in 456 men (80.2 ± 3.5 years) recruited from the general population in Gothenburg, Sweden. aBMD was measured using DXA. Incident fractures (71 men) were X-ray verified. Associations were evaluated using Cox regression. Cortical area [hazard ratio (HR) per standard deviation (SD) decrease, 2.05; 95% confidence interval (CI), 1.58 to 2.65], cortical bone mass (HR, 2.07; 95% CI, 1.58 to 2.70), and BVTV (HR, 1.62; 95% CI, 1.26 to 2.07), but not cortical porosity, were independently associated with fracture risk. These associations remained after adjustment for femoral neck aBMD and Fracture Risk Assessment risk factors (area: HR 1.96, 95% CI, 1.44 to 2.66; mass: HR 1.99, 95% CI, 1.45 to 2.74; BV/TV: HR 1.46, 95% CI, 1.09 to 1.96). After entering BV/TV and cortical area or bone mass simultaneously in the adjusted models, only the cortical parameters remained important predictors of fracture. HR-pQCT measurement of cortical area and mass might add clinically useful information for the evaluation of fracture risk.