The relationship between ultrasound and densitometric measurements of bone mass at the calcaneus in women.

Broadband ultrasound attenuation (BUA) of the calcaneus predicts axial density in women and is decreased in women who sustain hip fractures. To determine the relationship between ultrasonic and densitometric assessments of bone mass at the same site, BUA and velocity of sound (VOS) were correlated with bone density as measured by dual energy x-ray absorptiometry (DXA) at the calcaneus in 64 Caucasian women aged 35-83 years. BUA, VOS, and bone density in these women decreased annually as a function of age by 1.0%, 0.3%, and 0.9%, respectively. Holding age, years since menopause, height and weight constant, BUA correlated with VOS (r = 0.74, P < 0.001), and calcaneal density correlated with BUA (r = 0.73, P < 0.001) and with VOS (r = 0.66, P < 0.01). The results indicate that both BUA and VOS measurements reflect density at the calcaneus, but suggest that they measure properties of bone other than density and different from each other. The assessment of these additional properties may be useful in the prediction of fracture risk.