Endocrine Abstracts

Introduction: Body weight is positively correlated to bone mineral density. The exact mechanism is unclear but gravity may be one of the involved factors. Adipocytokines (leptin and adiponectin), secreted by the adipose tissue, are involved in bone turnover. We investigated the influence of body weight, body composition, and adipocytokines upon bone mass in pre and postmenopausal women.

Design: Cross-sectional study including six groups of 8 to 16 healthy female volunteers of different ages, pre and post menopausal, and weights (lean BMI<25 kg/m², overweight BMI 25–30 kg/m², and obese BMI>30 kg/m²). Excluding criteria were chronic disease and/or medication which could influence BMD. Lumbar BMD and BC were evaluated by DXA (Hologic). Serum leptin, adiponectin were evaluated by ELISA.

Results: Owing to the age heterogeneity, we have used Z score. Lumbar Z score was well correlated to body weight and body compartments. The best correlation was attained with lean mass, that was an independent predictor of bone mass irrespective of age (r²=0.4671) and weight (r²=0.2918).

Lean and postmenopausal women had lower BMD than premenopausal women (P<0.05). Bone mass of obese postmenopausal women did not differ from that of premenopausal women (P>0.5).

Bone mass was negatively correlated to leptin normalised to fat mass (r²=0.2128) and adiponectine (r²=0.1975).

Conclusions: Increased body weight prevents bone loss in postmenopausal women. 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 seems to be partially buffered by direct effects of adipokines on bone.