MEASUREMENTS OF POSTMENOPAUSAL BONE LOSS WITH A NEW CONTACT ULTRASOUND SYSTEM

Measurements of broadband ultrasonic attenuation (BUA) and velocity of ultrasound through the heel (heel velocity, HV) were performed with a Contact Ultrasonic Bone Analyzer (CUBA-Research model) in 229 women. The subjects consisted of 16 healthy young volunteers (Group 1, mean a ge 26 years), 170 healthy pre- and postmenopausal women (Group 2, mean age 53 years), and 43 osteoporotic women with radiographically define d vertebral crush fracture (Group 3, mean age 66 years). Subjects in G roup 1 had 10 repeated measurements in a study of short-term precision . Women in Groups 2 and 3 also had dual X-ray absorptiometry (DXA) sca ns to measure lumbar spine and femoral neck bone mineral density (BMD) . The BUA and HV measurements for all 229 women showed a significant c orrelation (r = 0.75, P < 0.001). The precision study on the subjects in Group 1 gave a root mean square coefficient of variation of 6.3% fo r BUA and 1.04% for HV. Linear regression analysis gave the following relationship between BUA and age for the 170 normal women in Group 2: BUA = 83.6 - 0.86 (age 40) dB/MHz (r = -0.31, P < 0.001, SEE = 16.3 dB /MHz). The relationship between HV and age was as follows: HV = 1614 - 2.3 (age 40) m/s (r = -0.33, P < 0.001, SEE = 42 m/s). Multivariate r egression analysis showed that in addition to age, years since the men opause was also a significant factor in determining both BUA and HV. I n the first 5 years following the menopause, BUA and HV decreased by 2 .2% and 0.3%/year, respectively, whereas in the next 10 years the rate s of decrease fell to 0.5% and 0.03%/year. The BUA and HV measurements on the 43 osteoporotic subjects in Group 3 gave mean T-scores of -2.1 and -1.9 compared with 59 premenopausal women, and mean Z-scores of - 1.3 and -0.9 compared with 26 age-matched normal women in Group 2, res pectively. In comparison, the lumbar spine and femoral neck DXA measur ements in the same subjects gave mean T-scores of -2.9 and -2.1 and me an Z-scores of -1.7 and -1.0, respectively. Lumbar spine BMD gave the best discrimination between women with osteoporotic vertebral fracture s and normal subjects. However, the difference between the lumbar spin e and BUA Z-scores was not statistically significant. Femoral neck BMD was equivalent to the ultrasound parameters in T-score and Z-score va lues.