Ultrasound bone densitometry of the calcaneus, determined with Sahara, in healthy Japanese adolescents: Japanese Population-based Osteoporosis (JPOS) Study

To establish the reference values for quantitative ultrasound (QUS) indices (speed of sound [SOS]), and broadband ultrasonic attenuation [BUA]) in healthy Japanese adolescents, and to evaluate the effects of age and body size on QUS in comparison with their effects on bone mineral density (BMD), 632 healthy adolescents aged 12 through 17 years recruited from a larger cohort study (Japanese Population-based Osteoporosis [JPOS] Study), were examined in terms of bone mass measurements by QUS at the calcaneus (Sahara; Hologic) and by dual-energy X-ray absorptiometry at the distal one-third radius and ultradistal forearm. We present sex- and age-specific mean values of the QUS and BMD indices. BMD increased significantly up to 17 years of age in males and up to 16 years in females. However, the age-related change in the QUS indices in males was not as clear as that seen for BMD and no age-related change in the QUS indices was observed in females. Significant positive correlation coefficients between BMD and body size were observed in both sexes even after adjusting for the effect of age. SOS showed no correlation with body size and BUA showed a positive but weak correlation with body size in both sexes. Thus, the relationships of age and body size to BMD and QUS were different from each other, even though the QUS indices had significant positive correlations with BMD, allowing for the effect of age.