Possible role of adiponectin and insulin sensitivity in mediating the favorable effects of lower body fat mass on blood lipids

Aims: The objective of this study was to investigate the role of insulin sensitivity and serum adiponectin concentration as determinants, in middle-aged men, of the relationship between lower body fat and blood lipids after truncal fat has been accounted for. Methods: Men ( 443) aged 39-65 yr, body mass index 18-43 kg/m(2), participated in the study. The following variables were measured: regional body fat distribution as assessed by dual-energy x-ray ab-sorptiometry, maximal oxygen uptake, physical activity, fasting levels of serum adiponectin, triglycerides, and high-density lipoprotein- and total cholesterol. Plasma glucose and serum insulin were measured in the fasting state and after an oral glucose load. Results: Lower body fat mass was inversely associated with serum triglycerides and total cholesterol and positively with serum high-density lipoprotein- cholesterol after adjustment for age, lean tissue mass, truncal fat mass, weight history, maximal oxygen uptake, and the level of physical activity ( P < 0.0005). Serum adiponectin level and Matsudas insulin sensitivity index were positively intercorrelated, and both were positively correlated to lower body fat mass. When including adiponectin and insulin sensitivity in the analyses, the relationships between lower body fat mass and serum lipids were partly explained. Conclusion: For a given level of truncal fat mass, a large lower body fat mass is associated with an advantageous blood lipid profile, which may be partially mediated by the relationships to both insulin sensitivity and serum adiponectin level.