The relationship between bone mineral density and ultrasound in postmenopausal and osteoporotic women

The aim of this cross-sectional study was to use a novel method of data analysis to demonstrate that patients with osteoporosis have significantly lower ultrasound results in the heel after correcting for the effect of bone mineral density (BMD) measured in the spine or hip. Three groups of patients were studied: healthy early postmenopausal women, within 3 years of the menopause (n = 104, 50%), healthy late postmenopausal women, more than 10 years from the menopause (n = 75, 36%), and a group of women with osteoporosis as defined by WHO criteria (n = 30, 14%). Broadband ultrasound attenuation (BUA), speed of sound (SOS) and Stiffness were measured using a Lunar Achilles heel machine, and BMD of the lumbar spine and left hip was measured using dual-energy X-ray absorptiometry (DXA). SOS, BUA and Stiffness were regressed against lumbar spine BMD and femoral BMD for all three groups combined. The correlation coefficients were in the range 0.52-0.58, in agreement with previously published work. Using a calculated ratio R, analysis of variance demonstrated that the ratio was significantly higher in the osteoporotic group compared with the other two groups. This implied that heel ultrasound values are proportionately lower in the osteoporotic group compared with the other two groups for an equivalent value of lumbar spine and femoral neck BMD. We conclude that postmenopausal bone loss is not associated with different ultasound values once lumbar spine or femoral neck BMD is taken into account. Ultrasound does not give additional information about patterns of bone loss in postmenopausal patients but is important in those patients with osteoporosis and fractures.