Relative contribution of weight-bearing and non-weight-bearing effect of adipose tissue to bone mineral density in postmenopausal women.

AIM: To investigate the relative contributions of weight-bearing and non-weight-bearing effects of adipose tissue to bone mineral density (BMD) in postmenopausal women. MATERIAL AND METHODS: The subjects were 228 postmenopausal women aged 50-75 years. Age, years since menopause (YSM), height, body weight, and body mass index were recorded. Trunk fat mass, body fat mass, bilateral leg BMD and lean (muscle) mass were measured by whole body scanning with dual-energy X-ray absorptiometry. The relationships of BMD to trunk and body fat mass were investigated using uni- and multivariable analyses. RESULTS: The amount of trunk fat mass and body fat mass were 8.7 ± 3.6 kg and 19.0 ± 5.9 kg, respectively. On Pearson's correlation test, right leg BMD was positively correlated with trunk fat mass (r=0.268, P<0.001) and body fat mass (0.299, P<0.001). On multiple linear regression analysis, trunk fat mass (t-value = 3.500, P<0.001), age (-2.431, P<0.05), and YSM (-2.564, P<0.01) were independent significant predictors of right leg BMD. However, body fat mass was not a predictor of BMD (-0.465, P=0.642). These relationships remained significant after further adjusting for right leg muscle mass. CONCLUSION: Trunk fat mass rather than body fat mass is a significant predictor of leg BMD at the most weight-bearing site, despite being less than half the amount of body fat mass. Thus, adipose tissue contributes more to BMD through non-weight-bearing effect rather than weight-bearing effect.

Difference in non-weight-bearing effects on bone mineral density between trunk and peripheral fat mass in women with polycystic ovary syndrome.

AIM: To investigate the difference in non-weight-bearing effects on bone mineral density (BMD) between trunk and peripheral fat mass in women with polycystic ovary syndrome (PCOS). METHODS: Subjects were 123 amenorrheic PCOS women with right side dominance. Age, height, body weight, and body mass index were recorded. Trunk, peripheral (extremities), trunk-leg fat ratio as an index of body fat distribution, left arm (non-weight-bearing site) lean mass and BMD were measured by dual-energy X-ray absorptiometry. Serum testosterone and estradiol levels were measured. Relationships of BMD with trunk, peripheral fat mass, and sex hormones levels were investigated. RESULTS: Trunk fat mass amount was 9.8 + or - 6.7 kg and was lower than the peripheral fat mass amount (12.2 + or - 4.4 kg, P < 0.01). On Pearson's correlation test, trunk fat mass and left arm lean mass were positively correlated with arm BMD (r = 0.359, P < 0.001 and r = 0.501, P < 0.0001, respectively), while peripheral fat mass and serum testosterone levels were not correlated with BMD (r = 0.083 and 0.114, respectively, NS). On multiple regression analysis, trunk fat mass was positively correlated with BMD (t-value = 3.465; P < 0.001), independent of age and height. However, this relationship disappeared after additionally adjusting for left arm lean mass. CONCLUSION: Trunk fat mass, despite the smaller amount, is more associated with arm BMD than peripheral fat mass is through its non-weight-bearing effects.

Non-weight-bearing effect of trunk and peripheral fat mass on bone mineral density in pre- and post-menopausal women.

OBJECTIVE: To investigate the non-weight-bearing effect of trunk fat mass (composed of visceral and subcutaneous fat mass) and peripheral fat mass (subcutaneous fat mass alone) on bone mineral density (BMD) in pre- and post-menopausal women. METHODS: The subjects were 412 pre-menopausal women, 20-50 years of age and 228 post-menopausal women, 50-75 years of age. Age, years since menopause (YSM), height, body weight, and body mass index were recorded. Trunk, peripheral (extremities), left arm (non-weight-bearing site), lean mass, and BMD were measured by dual-energy X-ray absorptiometry. RESULTS: In pre-menopausal women, the amount of trunk fat mass was 6.8+/-4.1 kg, which was significantly lower than the amount of peripheral fat mass (11.6+/-3.8 kg, p < 0.001). Although trunk fat mass was positively correlated with arm BMD on Pearson's correlation test, arm lean mass was the only significant predictor of BMD on multiple regression analysis. In post-menopausal women, the amount of trunk fat mass (8.7+/-3.6 kg) was also significantly lower than the peripheral fat mass (10.3+/-3.4 kg, p < 0.001). On multiple regression analysis, however, trunk fat mass, but not arm lean mass, was the significant predictor of BMD. In both groups, peripheral fat mass was not correlated with left arm BMD. CONCLUSION: The effect of adipocyte-derived biochemical factors on BMD may differ with menopausal status and the sites of adipocyte deposition.

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.