Leptin and body composition in healthy postmenopausal women

Background. Leptin has been proposed to be involved in central control of a diposity and fat distribution but the role of this peptide is controversial . The aim of our study was to test the relationship between serum leptin an d body composition, fat distribution, and some biochemical markers such as fasting insulinemia and lipoproteins in a population of healthy Italian pos tmenopausal women. Methods. One hundred and twenty-three postmenopausal women (62.1 +/-8.7 yea rs) were evaluated. Body composition (fat and lean mass) was assessed by du al-energy X-ray absorptiometry (DXA). Two regions of interest were determin ed for regional fat analysis. Serum leptin and insulinemia were measured by radioimmunoassay, lipoproteins with colorimetric methods and apolipoprotei ns nephelometrically. Results. Plasma leptin levels are strongly related to total fat mass, in gr ams (r=0.73, p <0.001) or as a percentage of soft tissue (r=0.75, p <0.001) , and to adiposity, calculated as ratio between lean and fat mass (r=0.76, p <0.001). A significant correlation was also found between serum leptin an d central fat distribution (r=0.29, p <0.01). As concerns biochemical marke rs, serum leptin was significantly related to fasting insulin (r=0.38, p <0 .001), total cholesterol (r=0.29, p <0.01), Apolipoprotein-B (r=0.35, p <0. 001), and triglycerides (r=0.22, p <0.05). When corrected for total fat mas s, the partial correlation coefficients remain significant for percentage o f total body fat (r=0.27, p <0.01), adiposity (r=0.23, p <0.01), and fat pr oportion in android region (r=0.18, p <0.05). Conclusions. These data indicate that leptin levels are related to adiposit y and fasting insulin levels; indeed fast insulin mantains significant corr elation with leptin (r=0.23, p <0.01) after controlling for fat mass. Andro id distribution of fat mass in elderly women is associated with leptin conc entration.