Three ultrasound parameters-broad band ultrasound attenuation (BUA), speed of sound (SOS) through the heel and average of standardized BUA and SOS (stiffness)-were measured with a LUNAR Achilles system (Lunar Corporation, Madison, WI, USA) in 9459 normal Japanese women (mean±SD 54.7±11.3yr, 15-90 yr) who have no history of ovariectomy, and 260 men (58.1±16.5 yr, 15-86 yr).
The bone mass values peaked in women aged 15-17 years (BUA 116±9, SOS 1572±23 and stiffness 97±11), and in men aged 15-16 (SOS 1590±20, stiffness 107±11) and in the age span 22-29 years (BUA 124±14).
The rates of bone loss were high in women aged 51-55 (stiffness 1.0%/yr), significantly high in the women who had been menopausal for less than 5 years (stiffness 2.0% yr).
We compared the mean values of the parameters in women with early menopause (≤45 yr) and late menopause (≥53 yr) more than 5 years after the menopause. In the early menopausal women, the mean BUA values at age 58-62, and those of BUA, SOS and stiffness at age 63-67 were significantly low (P<0.02) compared with the age-matched values in the late menopausal women, whereas no significant difference was observed between those in either of the two groups after 68 years of age.
There were significantly positive correlations between the 3 ultrasound parameters and height, body weight and obesity index, but SOS was not significantly correlated with body mass index.
These results indicate that the maximal bone mass in the os calcis is attained in very young women aged 17 or less and that loss in the calcaneus bone quality appears to be more dependent on menopause than aging in women 58-67 years old. In the older women, however, the loss of bone seems to be age-related.