Quantitative ultrasound of the calcaneus in Brazilian Caucasian women: Normative data are similar to the manufacturer's normal range

Quantitative ultrasound (QUS) can be a helpful alternative to identify oste oporotic patients. In this study we establish the QUS Brazilian normal rang e (BNR) and compare its values (means and standard deviations) with the man ufacturer's normal range (MNR). We measured three QUS parameters (broadband ultrasound attenuation, BUA; speed of sound, SOS; stiffness index, SI) at the right calcaneus in 352 healthy Caucasian Brazilian women, aged 20-84 ye ars. We studied the age-dependent changes in QUS values and correlation wit h body size and years since menopause (YSM). A comparison of fracture risk classification using the BNR and MNR is also presented. Age was the most si gnificant predictor for all QUS parameters (r = - 0.49 for BUA, r = -0.66 f or SOS, r = -0.64 for SI). Weight was accepted as the second determinant fo r BUA (final regression model: BUA = 101.3 - 0.282 x Age + 0.373 x Weight; p<0.001; adjusted R-2 = 0.33). Body mass index (BMI) was accepted as the se cond predictor for ST (SI = 94.8 -0.595 x Age + 0.851 x BMI; p<0.001; adjus ted R-2 = 0.44). Height and YSM were accepted as second and third determina nts for SOS values (SOS = 1718.7 - 1.147 x Age - 69.863 x Height - 0.521 x YSM; p<0.001; adjusted R2 = 0.45). There was a decline in SI of about 41% f rom the values in young adulthood to those of women in their eighties, abou t 76.4% of which occurred from age 45-49 years onward. Variation of mean SI with age from the BNR was consistent with the MNR in all but two 5-year ag e groups. III these two groups (50-54 years, p<0.01; 65-69 years, p<0.05), values derived from the BNR were 5.08% and 5.45% higher than the MNR values , respectively. Comparison of standard deviations in SI with age between th e two populations did not show statistically significant differences. Using the fracture risk criteria proposed by the manufacturer, we observed that the MNR was appropriate for skeletal fragility evaluation in Brazilian wome n.