Quantitative ultrasound measurements of the tibia and calcaneus in comparison with DXA measurements at various skeletal sites

The performance of quantitative ultrasound (QUS) measurements of the tibia and calcaneus was studied in 109 elderly people (age range 65-87 years). Br oadband ultrasound attenuation (BUA) and speed of sound (SOS) were measured at the calcaneus and SOS was assessed at the tibia. Short-term precision o f tibial QUS was studied in 16 volunteers. The coefficient of variation (CV ) was 0.4% and the standardized CV (sCV) was 4.4%. We compared the calcanea l and tibial QUS measurements with bone mineral density (BMD) measurements of the lumbar spine, femoral neck, trochanter and total body assessed by du al-energy Xray absorptiometry (DXA). Calcaneal QUS correlated better with B MD at various skeletal sites than tibial QUS. Calcaneal BUA showed higher c orrelations with BMD values of the lumbar spine, femoral neck, trochanter a nd total body than calcaneal and tibial SOS (r = 0.48-0.64, r = 0.30-0.47, r = 0.35-0.47, respectively; p<0.001). Body weight modified the relationshi ps between calcaneal and tibial QUS and BMD measurements of the hip. Higher body weight was associated with higher BMD values at the femoral neck and trochanter for the same calcaneal and tibial QUS values. After adjustments for body weight correlations of tibial and calcaneal QUS with BMD improved and were very similar. This suggests; that correction for body weight is im portant and could add to the predictive value of QUS measurements.