Aire Leppik

The influence of ghrelin, adiponectin, and leptin on bone mineral density in healthy postmenopausal women

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/m2). Body composition, BMC, and BMD were derived by dualenergy X-ray absorptiometry. Waist-to-hip (WHR) and waist-to-thigh (WTR) ratios were also obtained. Ghrelin was associated with total BMC (β = −0.945; P = 0.0001), total BMD (β = −0.959; P = 0.0001), lumbar spine BMD (β = −0.945; P = 0.0001), and femoral neck BMD (β = −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 (β = −0.931; P = 0.0001), total BMD (β = −0.940; P = 0.0001), lumbar spine BMD (β = −0.937; P = 0.0001), and femoral neck BMD (β = −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 (β = 0.912; P = 0.0001), total BMD (β = 0.907; P = 0.0001), lumbar spine BMD (β = 0.899; P = 0.0001), and femoral neck BMD (β = 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.

Influence of anthropometric parameters on the body composition measured by bioelectrical impedance analysis or DXA in children

Aim: To investigate the influence of anthropometric measures (skinfold thicknesses, girths, lengths and breadths/lengths) on (1) the whole body impedance and impedance index and (2) the body fat mass measured by means of DXA in children. Methods: Nine skinfolds, 13 girths, eight lengths and eight breadths/lengths were measured in 26 boys and 27 girls, 11–12 y of age. The somatotype components—endomorphy, mesomorphy and ectomorphy—were assessed according to the method of Carter and Heath. Body impedance at 50 kHz was measured (Multiscan 5000, Bodystat Ltd, UK) and impedance index (height2/impedance) was calculated. Four body components—total body fat mass and separate hands, legs and trunk fat mass—were determined using DXA. Results: Skinfold thicknesses did not influence body impedance or impedance index according to stepwise multiple regression analysis. Impedance index was influenced more by the girth measures than was body impedance. The leg length measures highly influenced the impedance index (50–81%, R2± 100). Different breadth/length parameters influenced body impedance and body impedance index (21–49%). Mesomorphy influenced body impedance only in boys (35%). Body fat mass measured by DXA was highly dependent on the measured skinfold thicknesses (59–92%). The influence of lengths and breadths/lengths on the total fat mass was significant (25–49%). Endomorphy characterized total fat mass as 86% and 52% in boys and girls, respectively.

Relationships between adiponectin, leptin, and blood lipids in physically active postmenopausal females

The aim of this study was to investigate the possible relationships between adiponectin and leptin with blood lipids (CHOL, HDL‐C, LDL‐C, and TG) in physically active postmenopausal women. One hundred and thirty‐four physically active practicing gymnastics (2–3 times per week) women between the ages of 51 to 85 years participated in this cross‐sectional study. Body height, body mass, waist‐to‐hip circumference ratio (WHR), and BMI were used as anthropometrical parameters. Body composition parameters (fat%, fat mass, fat free mass) were measured by DXA. The fasting adiponectin, leptin, CHOL, HDL‐C, LDL‐C, and TG were measured. From the anthropometrical and body composition parameters, only WHR correlated significantly with adiponectin (r = −0.306). In addition, adiponectin correlated with TG (r = −0.277) and leptin (r = −0.381). Leptin was positively related to body mass (r = 0.261), and BMI (r = 0.274) from anthropometrical parameters and body fat% (r = 0.288) and fat mass (r = 0.298) from body composition variables. No relationships emerged between leptin and blood lipids. We found that there are some significant relationships between adiponectin, leptin and anthropometrical and body composition parameters in physically active postmenopausal females. From blood lipids, only TG correlated significantly with adiponectin. Am. J. Hum. Biol. 22:609–612, 2010.

Relationships between bioelectric resistance and somatotype in 9- to 11-year-old children.

Bioelectrical impedance analysis (BIA) is an inexpensive, simple, and easy way to determine the total body water (TBW) and fat-free mass (FFM) in children.1 TBW and FFM are significantly related to stature squared divided by resistance (S2/R).2 It is likely that stature may not be the true conductor length when one uses the fourelectrode wrist-to-ankle method of bioelectrical impedance analysis (BIA). The true length could be better represented by the acromial stature and arm length.3 The aim of this study was to investigate the possible relationships between body resistance and somatotype in preadolescent children.