Influence of weight and body fat distribution on bone density in postmenopausal women

Objective-To determine whether obesity or body fat distribution induces a greater modification on bone remodeling biochemistry (BRB) and bone density in postmenopausal women. Methods-One hundred and thirteen postmenopausal patients were studied. They were initially divided according to body mass index (BMI), and afterwards by waist-hip ratio (WHR) as well as combinations of the two factors. Hormone measurements and assessments of BRB were also done. Dual-emission X-ray absorptiometry from the lumbar column and hip was performed with Lunar DPXL equipment, and the standard deviation in relation to young adult (T) and age-matched subiects (Z) was calculated. Statistical analysis was done by the Mann-Whitney U test. The relation of BMI and WHR with the variables was calculated by simple regression analysis. Results-When divided according to BMI, there was greater bone density in the femoral neck in those with normal weight. After dividing according to WHR, the Z scores had a trend to a lesser decrease in those with upper level body fat distribution. Divided according to BMI and WHR, obese patients with upper-level body fat distribution had greater bone density in the lumbar column than those with normal weight and lower-level body fat distribution. With the same WHR, those with normal weight had greater bone density than those who were obese. Conclusions-A beneficial effect of upper-level body fat distribution on bone density was found. It is greater than that from obesity alone, and obesity and upper-level body fat distribution have an additive effect on bone density.