Endocrine Abstracts

Body weight is positively correlated to bone mass. While gravity represents a stimulation stress for bone turnover, endocrine function of adipocytes may also influence bone.

Objectives: We investigated the relative influence of weight, body composition and leptin upon lumbar bone mass in pre and postmenopausal women.

Materials and methods: Cross-sectional study including six groups varying from 8 to 15 pre- / postmenopausal healthy volunteers with different weights (lean BMI <25 kg/m², overweight BMI 25–30 kg/m², and obese BMI >30 kg/m²), not exposed to antiosteoporotic therapy. Lumbar bone mineral density (BMD) and body composition (BC) were evaluated by dual X-ray absorptiometry (DXA, Hologic), while serum leptin was evaluated by ELISA.

Results: Lean and overweight postmenopausal women had lower lumbar BMD than premenopausal women (P<0.05).

Bone mass of obese postmenopausal women did not differ from that of premenopausal women. Body weight and compartments were all positively correlated to bone mineral content. The best correlation was attained with lean mass (r²=0.47 for the whole group), that was an independent predictor of bone mass irrespective of age (P<0.05, multivariate analysis, ANOVA). Leptin was an independent predictor for bone mass only for postmenopausal women (P<0.05).

Conclusion: Increased body weight prevents bone loss after menopause. Lean mass predicts bone mass independently of body weight irrespective of age. The beneficial role of fat mass and total body weight on bone mass through gravitational stress seem to be supplemented by possible direct effects of leptin on bone at postmenopausal women.