Rapid Cortical Bone Loss at the Distal Radius Is Associated With Higher Risk of Fracture in Older Men - The STRAMBO Study

Rapid loss of areal bone mineral density (aBMD) is associated with higher fracture risk after adjustment for confounders including initial aBMD. However, the link between bone microarchitecture decline and fracture is not clear. We studied the association between bone microarchitecture deterioration assessed prospectively over 4 years and the subsequent fracture risk in older men. Bone microarchitecture at the distal radius and tibia was assessed by high-resolution peripheral QCT (HR-pQCT; XtremeCT, Scanco Medical) (baseline, 4 years) in 732 men aged 60-87 years. During the 8-year follow-up, 109 men had fragility fractures. Areal BMD was assessed by dual-energy X-ray absorptiometry. After adjustment for age, weight, prior falls and fractures, distal radius aBMD (baseline, slope), and baseline distal radius total volumetric BMD (Tt.BMD), a faster decrease in distal radius Tt.BMD was associated with higher fracture risk (hazard ratio [HR] = 1.54/SD, 95% confidence interval: 1.20-1.95, p < .005). Rapid cortical bone loss was associated with higher fracture risk (cortical thickness: HR = 1.48; 1.15-1.90, p < .01; cortical BMD: HR = 1.38; 1.11-1.72, p < .01). The rate of trabecular bone loss at the distal radius and the rate of bone microarchitecture decline at the distal tibia were not associated with fracture risk. After adjustment for aBMD and distal radius HR-pQCT measures assessed after 4 years, changes in Tt.BMD were associated with higher fracture risk (e.g., Tt.BMD: HR = 1.37; 1.11-1.69, p < .005). Compared with the reference model (age, weight, prior fractures and falls, baseline and slope of aBMD, baseline HR-pQCT value), further addition of the slope of the HR-pQCT measure did not improve the fracture prediction. Thus, rapid cortical bone loss at the distal radius is associated with higher fracture risk in the multivariable models including baseline values of the HR-pQCT measure. However, repeated HR-pQCT measurements did not improve the assessment of the fracture risk in older men (compared with the reference model defined earlier). © 2023 American Society for Bone and Mineral Research (ASBMR).