Obesity as a determinant of regional bone mineral density

Total body and regional bone mineral density (BMD) and bone mineral content (BMC) in obese patients and healthy controls were assessed by dual-photon absorptiometry (DPA) in this study. In both men and women, BMD values in total body, pelvis, upper and lower extremities were significantly (p less than 0.05) higher in the obese group (body mass index greater than 28) than in the non-obese group (body mass index less than 23). These BMD values correlated significantly with body weights and with percentages of body fat. In the obese group, 8 massively obese women were treated with an 8-week very low calorie diet (VLCD), resulting in a 13.4 kg of mean body weight reduction. Although BMC in total body and in pelvis were maintained, significant decreases of BMC in the upper (from 275 +/- 30 to 255 +/- 26 g) and lower (from 871 +/- 47 to 805 +/- 31 g) extremities were observed following the 8-week VLCD treatment. These results suggest that body fat mass affects BMD and BMC preferentially in weight bearing bone, the changes of which are not always associated with changes in total body BMD or BMC.