OBJECTIVETo investigate the relative contribution of fat mass and lean mass on bone mineral density (BMD) in premenopausal healthy women.

METHODSThe BMD at lumbar spine, proximal femur and total body, together with fat mass and lean mass was determined by dual-energy X-ray absorptiometry (DEXA), the body height, weight, waist, and hip circumference were also measured, and body mass index (BMI) and waist-hip ratio were calculated in 282 premenopausal women.

RESULTSFat mass was a major determinant for BMI, BMI and lean mass were positively related with L2-4, proximal femur and total body BMD (P = 0.000 for all), and lean mass were the only independent factor contributing to L2-4 (standardized coefficient beta = 0.282, P = 0.000), proximal femur (beta = 0.336, P = 0.000) and total body BMD (beta = 0.361, P = 0.000) in stepwise regression analysis. The relationship between BMI and BMD was further improved after controlling fat mass, while decreased or even lost when controlling lean mass.

CONCLUSIONSLean mass was an important factor determining BMD in premenopausal women.