Endocrine Abstracts

Gravitational stress influences bone mass. Adipose tissue represents a supplementary source of estrogens at postmenopausal women, via aromatization of androgens. We evaluated the importance of weight and fat tissue on bone mass at premenopausal or postmenopausal women in a cross-sectional study upon a group of 138 women between 25 and 77 ys old and with a BMI between 17.1 and 44.3 kg/m². Fifty six women were menstruating, 15 were perimenopausal and 68 were postmenopausal. We assessed the correlation between lumbar bone mineral content (Z and T scores, measured by dual X ray absorptiometry) and: body mass, adipose and lean tissue mass (measured by electric impedance). Postmenopausal women had a significantly lower bone mass than premenopausal women (mean T score of −1.87+/− 0.14 vs −0.91+/− 0.16, P< 0.05). Lean (BMI <24 kg/m²) postmenopausal women had an even lower mineral content (T score =−2.17+/−1.23, P<0.01 when compared to premenopausal women), whereas overweight postmenopausal women (BMI >26 kg/m²) had an intermediate T score between premenopausal and postmenopausal lean women (−1.63+/−0.19, P<0.05). Total body mass, lean and fat mass were all correlated to bone mineral content, having comparable predictive powers in premenopausal women. When applied to postmenopausal women, correlation significance of fat mass with the Z score augmented (R²=0.329 vs R²=0.253 for premenopausal women), whereas correlation significance between total or lean body mass and Z score decreased (in the case of total body mass - R²=0.148 vs R²=0.28 for premenopausal women). Adipose tissue mass seems therefore to be an important BMD predictive factor. Its predictive value increases in postmenopausal women, whereas total and lean body mass are correlated to BMD especially in premenopausal women, which are not yet submitted to estrogenic depletion.