Background: Quantitative ultrasound (QUS) has been claimed as an alternative technique for risk assessment of hip fractures associated with osteoporosis. However, reports concerning modest correlations between QUS parameters and dual energy X-ray absorptiometry (DXA) in women raise questions about the reliability of QUS technology to predict bone mineral density (BMD). Partially, the lack of stronger correlations may be due to heterogeneity in bone architecture deterioration which may be more pronounced in older than in younger women. Therefore, it was thought important to study QUS/DXA interrelationships in subgroups of pre- and postmenopausal women.
Methods: We studied 217 pre- and postmenopausal women between the ages of 25 and 75 years, who were referred for a BMD measurement because of osteoporosis in at least one family member either in the first or in the second degree. All women had a calcaneal QUS and a DXA measurement at the lumbar spine, total hip and femoral neck.
Results: The linear regression coefficients between the QUS parameters broadband ultrasound attenuation (BUA) and speed of sound (SOS) and DXA at the various sites in the group as a whole were 0.53 to 0.54 (P<0.0001). Significantly lower regression coefficients between BUA and DXA at the total hip and the femoral neck were found in premenopausal women (r=0.31 and 0.38, P<0.0001) compared to postmenopausal women (r=0.56 and 0.53, P<0.0001). For SOS there was no significant difference between the regression coefficients in the pre- and postmenopausal group. The overall prevalence of osteoporosis as assessed by DXA in the total group was 25% (6% in the pre- and 36% in the postmenopausal group). BUA failed to detect osteoporosis in all five premenopausal women but also in 20 out of 50 postmenopausal women with osteoporosis according to DXA measurements. SOS measurements were even worse in this respect.
Conclusions: Linear regression coefficients between calcaneal QUS parameters and DXA are only modest considering a group of 25--75-year-old Dutch women. In the subgroup of premenopausal women correlations between BUA and BMD at the hip and femoral neck are worse compared to those in postmenopausal women. The predictive value of QUS parameters for BMD is limited, therefore it is not appropriate to use QUS as a surrogate for DXA.