body weight is a better predictor of bone mineral density than body mass index in postmenopausal women

background: we aimed to evaluate the effect of body weight and body mass index (bmi) on bone mineral density (bmd) in healthy postmenopausal iranian women.    material and methods: two hundred postm­enopausal women (age between 51 and 69 years) who had presented to the nuclear medicine center at shariati hospital in tehran, iran between april 2012 and august 2013 were included in this cross sectional study. of these 46 healthy women who met the study criteria constituted for evaluation. after recording weight and height of individuals, body mass index (bmi) (kg/m2) was calculated as weight (kg) divided by height square (m2). bone mineral density (bmd) in femoral neck (fn) and lumbar spine sites (l1-l4) were mea­sured by dual-energy x-ray absorptiometry (dexa).   results: we observed statistically significant negative correlation between bmd measurements at femoral neck and lumbar1-4 spine with age and significant positive correlation with weight and bmi. stepwise multiple linear regression analysis showed that only weight and age, after adjustments to bmi determined lumbar1-4 spine bmd (r² =23%) and femoral neck bmd (r² =28.6%).    conclusions: these results suggest that the relationship between body weights and bmd is   stronger than the between bmi and bmd. therefore, in comparison with body mass index, body weight alone is a better predictor of bone mineral density.