Different rates of forearm bone loss in healthy women with early or late menopause

The aim of this study was to evaluate whether healthy women with early or late menopause have different rates of age- and menopause-related bone loss, and whether premature menopause really represents a risk factor for osteopenia. Healthy women aged from 27 to 84 years (n=2204), with no history of fractures, were divided into two groups according to their age at menopause (AAM): group A with AAM43, and group B with AAM50 years. Bone mineral density (BMD) was measured in the distal non-dominant forearm by single-photon absorptiometry. Group B had a significantly lower average BMD than group A (group A, 0.430±0.074 g/cm²; group B, 0.419±0.081;p=0.003); however, the average age of group A was significantly lower, and weight and height were significantly higher. When women older than 50 years of age were divided into five age-matched subgroups, BMD was significantly lower in women with AAM43 years up to 60 years; after that age this difference disappeared and, in the oldest subgroups, BMD was significantly lower in group B than in group A. Independent variables such as age, AAM and body mass index (BMI) explain about 30% of the variation of BMD, using a multiple linear regression analysis. In both groups age and BMI weighted more than AAM in determining BMD. When BMD was plotted versus either chronological age or years since menopause, women with late menopause showed a significantly faster bone loss than those with early menopause. In conclusion, women with premature menopause have a lower peripheral bone mass than women with later menopause up to 60 years of age, but not later, when the risk of fractures is higher. This seems to be due to the fact that women with late menopause lose bone faster than those with early menopause.