A prospective study of bone loss in menopausal Australian-born women

Two hundred and twenty-four women (74 pre-, 90 peri-, 60 post-menopausal). aged 46-59 years, from a population-based cohort participated in a longitud inal study of bone mineral density (BMD). BMD was measured by dual-energy X -ray absorptiometry (DXA) at the lumbar spine and femoral neck and the time between bone scans was on average 25 (range 14-41) months. The aim of the study was to assess changes in BMD in relation to changes in normal menopau sal status. During the study period women who were between 3 and i' months past their last menstrual period (n = 22, late perimenopausal) at the time of the second bone scan had a mean (SE) annual change in BMD of -0.9% (0.4% ) at the lumbar spine and -0.7% (0.6%) at the femoral neck (both p < 0.05 c ompared with women who remained premenopausal). In the women who became pos tmenopausal (n = 42) the mean annual changes in BMD were -2.5% (0.2%) at th e lumbar spine and -1.7% (0.2%) at the femoral neck (both p < 0.0005), and in the women who remained postmenopausal (n = 60) they were -0.7% (0.2%) pe r year and -0.5% (0.3%) per year respectively (both p < 0.05), compared wit h women who remained premenopausal. In the 1-3 years after the final menstr ual period (FMP) there was greater bone loss from the lumbar spine than the femoral neck (p < 0.05). In women who were menstruating at the time of the second bone scan and whose FMP could be dated prospectively (n = 35), high er baseline oestradiol levels were associated with less lumbar spine bone l oss (p < 0.005). In the women who remained postmenopausal there was an asso ciation between baseline body mass index (BMI) and percentage change per ye ar in femoral neck BMD (p<0.05), such that women with higher BMI had less b one loss. In conclusion, during the time of transition from peri- to post-m enopause, women had accelerated BMD loss at both the hip and spine.