[Comparison of bone mineral levels in healthy Japanese perimenopausal women measured by dual energy X-ray absorptiometry and ultrasound methods].

One hundred and seventy Japanese perimenopausal women, 44 to 65 years old (average 55.3), living in the Tokyo metropolitan area were evaluated for bone minerals by two methods of measurement--DXA (dual energy x-ray absorptiometry) measured at the 2nd-4th lumbar spine and three areas of proximal femur, and US (ultrasound bone densitometry) measured at the calcaneal area of the foot. Menopausal status was determined by interview, and anthropometric measurements, grip strength and various foot measurements including length, breadth, girth, area, and angles were taken. The relationship between these physical factors and bone minerals measured by DXA and US was considered in comparisons of evaluations of bone mineral condition by these two different methods. The results were as follows: 1) The means of bone mineral density (BMD) at four sites by DXA and of broadband ultrasound attenuation (BUA) by US decreased with age significantly in a graded fashion. The mean of speed of sound (SOS) by US, however, did not show a significant decrease by age. 2) All measurements but one (SOS by US) showed significant differences among three groups of menopausal status (premenopause, < 6 years after menopause, and > or = 6 years after menopause) by ANOVA. 3) Concerning the relationship between physical variables and bone measurements, all measurements for bone mineral showed significant correlations with body weight (positive) and age (negative) except SOS by US. Grip strength had significantly positive correlations to all bone measurements. BUA by US showed strong correlations with several of the foot measurements. 4) Correlations between bone measurements by DXA and US, were all strong and positive particularly in the combinations within the measurement by DXA. 5) Multiple regression analysis of the physical variables to each bone measurement as the dependent variable, showed significant relationship of age (negative) and body weight or BMI (positive) to each bone measurements except for SOS. The foot area remained significant for BUA. The significant relationship of combinations of physical factors that persisted for US were somewhat different from those in DXA. These results indicate that the level of accuracy of measurements of bone mineral by ultrasound may not necessarily be equivalent to that of dual energy x-ray absorptiometry measurements and must be utilized with caution especially in risk factor analysis of osteoporosis.