The association of body fat mass (FM) with bone mineral mass (BMC) and bone mineral density (BMD) has been attributed to a mechanical load exerted on the skeleton by FM and by the effect of different hormones. The aim of the present study was to determine whether there is a relationship between ghrelin, adiponectin, and leptin with BMC and BMD in healthy postmenopausal women (n = 88; age, 68.9 +/- 6.8 years; body mass index, 27.4 +/- 3.6 kg/m(2)). Body composition, BMC, and BMD were derived by dual-energy X-ray absorptiometry. Waist-to-hip (WHR) and waist-to-thigh (WTR) ratios were also obtained. Ghrelin was associated with total BMC (beta = -0.945; P = 0.0001), total BMD (beta = -0.959; P = 0.0001), lumbar spine BMD (beta = -0.945; P = 0.0001), and femoral neck BMD (beta = -0.957; P = 0.0001), and remained associated (P < 0.041) in different analyses that controlled for measured body composition and hormonal and insulin resistance values. However, the associations between ghrelin and measured bone mineral values were no longer significant (P > 0.149) when adjusted for body fat distribution values (WHR, WTR). Adiponectin was significantly related to total BMC (beta = -0.931; P = 0.0001), total BMD (beta = -0.940; P = 0.0001), lumbar spine BMD (beta = -0.937; P = 0.0001), and femoral neck BMD (beta = -0.940; P = 0.0001) values, and these relationships remained significant (P < 0.019) after adjusting for measured body fat, hormonal, and insulin resistance values but not when adjusted for fat-free mass (FFM; P > 0.106). In addition, significant associations of leptin with total BMC (beta = 0.912; P = 0.0001), total BMD (beta = 0.907; P = 0.0001), lumbar spine BMD (beta = 0.899; P = 0.0001), and femoral neck BMD (beta = 0.906; P = 0.0001) were found. These associations remained significant (P < 0.010) in different analyses that controlled for hormonal and insulin resistance values, but the associations between leptin and bone mineral values were no longer significant (P > 0.145) when adjusted for specific body composition values (WHR, WTR, FM, and FFM). In conclusion, it appears that the influence of plasma ghrelin, adiponectin, and leptin levels on BMC and BMD values is mediated or confounded by the specific body composition parameters in healthy postmenopausal women.

Prospective comparative study, Level II.

Purpose: We investigated the relationship between the decrease in bone mineral mass (BMC) and bone mineral density (BMD) values with baseline adipocytokine and ghrelin concentrations in physically active postmenopausal women. Methods: Leptin, adiponectin, ghrelin, BMC, BMD and different body composition values were measured in 35 women (age: 69.7G6.0 years) before and after a 12-month prospective study period. Results: Significant (P!0.05) decreases in fat-free mass (FFM) (by 2.56%) and BMC (by 1.63%) and increases in adiponectin (by 14.8%) were seen in older females as a result of the study period. The independent variables that were associated with decreases in total BMC were baseline fat mass (FM) and adiponectin explaining 30.6% (R 2 !100) of the total variance. In another model, baseline FFM and leptin were the independent variables that explained 20.6% (P!0.05) of the total variance in the decreases in total BMD value. The variables that were associated with decreases in femoral neck BMD were FM and leptin (R 2 Z0.102; P!0.05), while the independent variables were baseline trunk fat:leg fat ratio and adiponectin in the model with decreases in lumbar spine BMD as the dependent variable, and accounted for 13.1% (P!0.05) of the decreases in BMD variance. Conclusions: Initial adiponectin concentration together with specific body composition characteristics predicted loss in BMC and lumbar spine BMD values, while initial leptin concentration together with specific body composition parameters determined the loss in total and femoral neck BMD values in physically active older women.

No abstract

This study is aimed to evaluate whether circulating adiponectin concentration is associated with physical activity (PA) level in healthy older females. To date, daily PA in older adults (> or = 65 years) has primarily relied on self-report. This study used accelerometry, which objectively measured minute-by-minute movement to assess PA volume and intensity performed by elderly females. In addition, body composition, leptin and insulin resistance values were measured to assess the influence of these parameters on the possible relationship between adiponectin and PA levels in this specific age group of older women. On 49 women (mean age: 73.6 +/- 4.2 years), adiponectin, leptin, insulin resistance, body composition and 7-day PA parameters were measured. Average daily accelerometer step counts and time spent in different PA levels were obtained from 7-day PA measurement. Average daily accelerometer step-count was 7,722 +/- 3,069 steps day(-1) and the recommended 150 min weekly of at least moderate/vigorous PA in bouts of at least 10 min was achieved by 71.4% (35/49) of the participants. Correlation analysis showed that plasma adiponectin concentration (16.0 +/- 6.1 microg ml(-1) ) was related (P < 0.001) to steps per day (r = 0.438) and leptin (r = -0.443) values. Multivariate regression analysis further revealed that only steps per day and leptin were independent predictors of circulating adiponectin concentration in healthy elderly females. In conclusion, these data support the hypothesis that being physically active is associated with better adiponectin concentration and a reduced risk of having metabolic disease risk in the specific group of healthy elderly females.