ASSOCIATIONS BETWEEN BODY MORPHOLOGY AND BONE-MINERAL DENSITY IN PREMENOPAUSAL WOMEN

To investigate whether body morphology, obesity and its long time evol ution were associated with lumbar and femoral bone mineral density (BM D) in premenopausal women of the same age. Design: Cross-sectional stu dy. Subjects: 72 healthy premenopausal women born in 1950 (42 years) w ith a regular physical activity. Measurements: BMD measured by dual-X- ray absorptiometry (DEXA) at lumbar spine and proximal femur; body wei ght, body mass index (BMI), BMI at 20 years (BMI-20), increase in BMI since age of 20 (BMI->20), body circumferences (breast, waist, hip) an d their ratios (WHR, BHR, WBR), smoking and alcohol intake. Results: L umbar spine BMD did not correlate with any anthropometric measurement. Femoral BMDs correlated positively with weight, BMI, BMI-20, breast, waist, WHR and BHR. The BMI-20 explained the 5% and the current BMI th e 13% of variance of total femur BMD. After adjustment for weight or B MI, breast circumference and BHR remained significantly correlated wit h all femoral BMDs sites except neck. Weight was the best predictor fo r neck BMD (R-2 = 0.08; p < 0.02), and BHR for Ward's triangle (R-2 = 0.12; p < 0.01) and trochanter (R-2 = 0.10; p < 0.001). Alcohol intake , cigarette smoking, and age of menarche were not related to BMDs. Con clusion: In premenopausal women of the same age, lumbar spine BMD was not associated with any anthropometric measurement. Greater BHR and it s long time of evolution may be determinants of greater femoral BMD (t rabecular), whereas body weight may be determinant of femoral neck BMD (cortical). Further studies are needed to determine whether large bre ast to hip ratio may be considered as a protective factor for femoral osteoporosis.