Comparison of bone mineral density at various skeletal sites with quantitative ultrasound parameters of the calcaneus for assessment of vertebral fractures.

This study investigated the role of quantitative ultrasound (QUS) for evaluation of fracture risk in comparison with bone mineral density (BMD) measurement. Our subjects were postmenopausal Japanese women (n = 260; age, 67 +/- 6.1 years) who were examined for bone densitometry, QUS, and spinal X-ray examination at our department between 1992 and 1996. The subjects were categorized into three groups by the number of atraumatic fractured vertebrae: NF, no vertebral fractures: F1, one vertebral fracture; F2, two or more vertebral fractures. We compared the measured parameters to determine their association with the number of fractured vertebrae. Differences among groups were compared and analyzed by Student's t-test. Odds ratios were also calculated after age adjustment, as well as age and lumbar or calcaneal parameters. Between NF and F1, lumbar BMD and BMD of the Ward's triangle showed more significant differences than other values, while between F1 and F2, whole-body BMD and QUS parameters showed more significant differences. Lumbar BMD also showed the highest age-adjusted odds ratio in differentiating F1 from NF. Although QUS parameters showed no power to differentiate between NF and F1, these values showed higher odds ratios than other measurements for discriminating between F1 and F2. Adjustment for bone density did not totally abolish the association between QUS parameters and vertebral fracture. Additionally, the combination of lumbar BMD and QUS ("stiffness") clearly showed a high power to discriminate NF from F1 + F2. In conclusion, we showed that QUS measurement is effective in evaluating fracture risk in advanced osteoporosis, while lumbar dual X-ray absorptiometry is effective in evaluating risk in early osteoporosis.