Heel ultrasound in women after long-term ERT compared with bone densities in the forearm, spine and hip.

To compare heel ultrasound values with bone densities at different measurement sites as determined by single photon absorptiometry (SPA) and dual-energy X-ray absorptiometry (DXA) in long-term users of estrogen replacement therapy (ERT), we analyzed data from 30 users of estradiol implants (mean duration of treatment 16 years) and 32 non-users, comprising 28 complete age-matched pairs. The precision errors in vivo of ultrasound measurements were 0.18%, 1.3% and 1.5% for speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness index, respectively. In the controls, ultrasound parameters correlated well with values from SPA and DXA measurements (r = 0.51-0.63, p < 0.004). In long-term users of ERT, however, measurements with ultrasound did not correlate with DXA in the spine and hip (r = 0.01-0.31, NS) but correlated well with SPA in the forearm (r = 0.47-0.66, p < 0.009). Implant users, compared with non-users, had small and just significantly different values when measured by ultrasound (at most 12%, p = 0.03-0.04) but significantly higher bone mineral densities (18%-25%, p = 0.0001-0.01) in the forearm, spine and hip when measured by SPA or DXA. Data indicated that a substantial proportion of long-term users of estrogen may be non-responders concerning the effect of estrogen on bone qualities expressed in heel ultrasound values. In a multivariate regression analysis the effect of increasing age and increasing treatment duration were both negative for the ultrasound parameters.(ABSTRACT TRUNCATED AT 250 WORDS)