Background: Adiponectin, an adipocyte-derived hormone found in lower concentration with greater adiposity, is suggested to reduce the risk of insulin resistance, atherosclerosis, and cardiovascular disease. We tested this hypothesis in a healthy, nonobese population.
Methods and results: Brachial artery flow-mediated endothelial-dependent vasodilation and distensibility, measures of vascular function relevant to the early atherosclerotic process, were determined in 294 adolescents (aged 13-16 yr) using high-resolution vascular ultrasound. Fasting insulin concentration and the homeostasis model assessment of insulin resistance were used to estimate insulin resistance. Fat mass was measured by bioelectric impedance analysis; fasting serum adiponectin concentration by RIA; and lipid profile, fasting insulin, glucose, and C-reactive protein concentrations using standard laboratory techniques. Adiponectin concentration was associated with insulin resistance independent of potential confounding factors (e.g. -1.3% change in fasting insulin concentration per 10% increase in adiponectin concentration; 95% confidence interval, -2.4% to -0.1%; P = 0.03), but not with flow-mediated endothelial-dependent vasodilation or arterial distensibility.
Conclusions: Lower adiponectin concentration was associated with lower insulin sensitivity in a healthy, nonobese population. Our study supports the hypothesis that adiponectin benefits insulin sensitivity from a young age but, in contrast to experimental models and data from older subjects, does not affect vascular changes associated with early atherosclerosis.