Broadband ultrasound attenuation (BUA) is a new technique for investigating bone status. We evaluated its use in osteoporosis. To assess in vivo reproducibility, we determined the coefficient of variation (cv) on the basis of five measurements (with repositioning) of the same foot in 50 women. The cv was 2.8 +/- 1.7%. BUA values were similar in the right feet and left foot and were correlated with bone density in the calcaneal area investigated (r = 0.8, p < 10(-4). BUA of the calcaneus was correlated with bone density in the lumbar spine, femur, and forearm in 240 healthy postmenopausal women (correlation coefficients 0.36 to 0.55; p < 10(-4)). BUA decreased with age, with a sharper drop during the first years following menopause. Mean broadband ultrasonic attenuation in 37 females with osteoporosis (58.92 +/- 11.59 dB/MHz) is lower than controls (66.10 +/- 15.29 dB/MHz, p = 0.04). Areas under receiver operating characteristic curves, used to evaluate the discriminating value of BUA in osteoporosis and osteopenia, were 0.79 and 0.72, respectively. The kappa coefficient of concordance between BUA and spinal density was 0.59. These data demonstrate that BUA cannot replace bone density measurements. Prospective studies are needed to investigate the potential role of this technique for identifying women at high risk for osteoporotic fractures.