INFLUENCE OF BODY-MASS INDEX ON THE AGE-RELATED SLOPE OF TOTAL AND REGIONAL BONE-MINERAL CONTENT

The influence of body mass index (BMI) on T scores for total body bone mineral content (TBBMC) and regional bone mineral content (RBMC) was studied in 186 healthy women: 100 postmenopausal, 35 perimenopausal, a nd 51 premenopausal. The three groups were divided by BMI >25 kg/m(-2) and BMI <25 kg/m(2) and the postmenopausal women were further subdivi ded by years since menopause (YSM): <10, 10-20, and >20. Tartrate-resi stant acid phosphatase (TRAP) concentration was higher in perimenopaus al and postmenopausal women with BMI <25 kg/m(2) (P < 0.001). T scores for TBBMC and for axial or peripheral RBMC differed (P < 0.05 in all) between women with BMI >25 kg/m(2) and BMI <25 kg/m(2). The rate of p erimenopausal and postmenopausal age-related slope of BMC, as reflecte d in all measurements, differed with BMI. In the overall group of wome n, the T score for TBBMC correlated significantly with BMI (r = 0.46, P < 0.0001); this correlation increased when adjusted for age (r = 0.6 2, P < 0.0001). BMI correlated with TRAP only in postmenopausal women (r = 0.57, P < 0.0001). Yearly TBBMC decline was twice as high in post menopausal women with BMI <25 kg/m(2) (P = 0.0004) than in those with BMI >25 kg/m(2); the decline of trunk RBMC was more significant (P < 0 .0001). These findings confirm the influence of BMI and gonadal status on bone mass.