Bone mineral density and hormone levels in menopausal Australian women

To assess the relationships between bone mineral density (BMD) at the lumbar spine and femoral neck and menopausal status, age, physical variables, and lifestyle and gynecological factors. BMD and follicle-stimulating hormone (FSH), estradiol and inhibin levels were measured in 167 women born in Australia, aged 46-57 years, who had no record of receiving hormone replacement therapy. Using the premenopausal group as a baseline, the FSH level was higher in peri- and postmenopausal subjects (p < 0.0005), and estradiol and inhibin levels in the postmenopausal women were lower (p < 0.0005). Mean (+/- SE) lumbar spine and femoral neck BMD were 15 +/- 3% and 10 +/- 3% lower, respectively, in postmenopausal than in premenopausal women. Lumbar spine BMD decreased with increasing age in perimenopausal women only (p < 0.005), and femoral neck BMD decreased with increasing age in the pre-, peri- (p < 0.05) and postmenopausal women. The difference between femoral neck BMD in the pre- and postmenopausal women was explained by the difference in age between these groups, whereas for lumbar spine BMD the menopausal status was an additional determining factor. There was a negative effect of smoking on femoral neck BMD (p < 0.05) in postmenopausal women. In the perimenopausal decade the femoral neck BMD is primarily dependent on age, whereas lumbar spine BMD is dependent on both age and menopausal status.