BONE-DENSITY IN WHITE BRAZILIAN WOMEN - RAPID LOSS AT THE TIME AROUNDTHE MENOPAUSE

Dual energy x-ray absorptiometry (DXA) was used to measure bone minera l density (BMD) of the lumbar spine and proximal femur (neck, Ward's t riangle, and trochanter) in 417 normal women (aged 20-79) living in Sa o Paulo, Brazil. Bone density decreased with age at all sites. At the spine, the greatest decrease occurred during the sixth decade, with an average 11.4% bone loss compared with the previous decade. Stratifyin g the subjects according to menopausal status revealed that the fastes t bone loss occurred at the time around the menopause (ages 45-60) whe n the rate of bone loss (-0.66%/year) was almost twice as rapid as in postmenopausal women (-0.39%/year). Although significant linear rates of bone loss were detected in all proximal femur sites before the meno pause, a menopause-dependent pattern was less evident than at the spin e. Lifetime rates of bone loss at the appendicular skeleton were -0.43 , -0.62, and -0.35%/year at the femoral neck, Ward's triangle, and tro chanteric area, respectively. After the menopause, BMD declined with m enopausal age at all sites, although the rate of bone loss was faster at the femoral neck (-0.62%/year) and Ward's triangle (-0.84%/year) th an at the spine (-O.49%/year). The results are consistent with the not ion that in women, the fastest bone loss occurs at the time around the menopause, most likely consequent to ovarian failure; and that faster rates of bone loss are detected at the proximal femur than at the lum bar spine in late postmenopausal women.