Distribution and determinants of adiponectin, resistin and ghrelin in a randomly selected healthy population

Adiponectin, resistin, ghrelin and the IGF-I system seem to play an important role in the regulation of body composition throughout life, but the mechanisms are not well understood. The aim of our study was to analyse the distribution among sexes and all decades of the adult life of adiponectin, resistin and ghrelin and their relationship with anthropometric, body composition parameters and the IGF-I system.

One hundred and thirty-four men and 127 healthy women were included in the study.

Plasma concentration of adiponectin, resistin, ghrelin, total IGF-I, free IGF-I and IGFBP-3 were determined in all subjects. Body composition was evaluated by bioelectrical impedance.

Resistin and ghrelin were not affected by age. Plasma adiponectin correlated negatively with age, body mass index (BMI), waist-to-hip ratio (WHR), waist circumference (WC), fat mass (FM) and body fat (BF) in men. Adiponectin correlated negatively with WHR and positively with free IGF-I in women. Resistin correlated positively with BMI and WC only in men, and ghrelin correlated positively with WC, BMI and FM and negatively with free IGF-I in men. In multiple regression analysis adiponectin remained associated with WHR (beta=-0.19, P=0.01) in women. Resistin was positively associated with BMI (beta=0.30, P=0.003) in women and ghrelin was negatively related to free IGF-I (beta=-0.158, P=0.019) in men.

Plasma adiponectin declines with age and is negatively associated with FM in men. Our data suggest the existence of a positive correlation of adiponectin and the IGF-I axis in women and of an inverse relationship between ghrelin and the IGF-I system in men.