Difference in segmental lean and fat mass components between pre- and postmenopausal women.

OBJECTIVE: To investigate the differences in segmental body composition (lean and fat mass components) between pre- and postmenopausal women.
DESIGN: Participants were 413 premenopausal women aged 20 to 53 years old and 229 postmenopausal women aged 50 to 75 years old with right-side dominance. Age, height, weight, body mass index, age at menopause, and years since menopause were recorded. The percentages of fat mass in the arms, trunk, legs, and total body were measured by dual-energy x-ray absorptiometry. The ratio of trunk to leg fat mass (trunk-leg fat mass ratio) was also measured by dual-energy x-ray absorptiometry.
RESULTS: The percentage of trunk fat mass and the trunk-leg fat mass ratio were significantly higher in postmenopausal women, but the percentages of leg fat mass did not differ. In the two groups, percentage of trunk fat mass and trunk-leg fat mass ratio were similarly and positively correlated with age. However, percentage of leg fat mass did not correlate with age. The percentage of fat mass at each segmental site and the trunk-leg fat mass ratio did not differ between premenopausal women aged 50 to 53 years old (n=52) and age-matched postmenopausal women (n=43, years since menopause=2.8+/-1.8).
CONCLUSIONS: Aging rather than menopause contributes to the increase in the percentage of trunk fat mass. However, the percentage of leg fat mass does not change with aging. Upper body fat distribution in postmenopausal women may be more attributable to aging than to menopause.