Plasma adiponectin levels in relation to carotid intima media thickness and markers of insulin resistance

Background - Circulating adiponectin is a marker for insulin sensitivity, derived from fat cells. It is largely unknown if adiponectin is also an independent marker for early atherosclerosis. Methods and Results - Plasma adiponectin levels were measured in 373 men and 514 women of middle-age by a time-resolved immunofluorometric assay. The subjects were sampled stratified for degree of insulin sensitivity (HOMA-IR). An ultrasound measurement of the right common carotid artery intima media thickness (IMT) was made. When the distribution of adiponectin was stratified into sex-specific quartiles (Q1 to Q4), men in Q4 differed from Q1 in higher mean age and high-density lipoprotein (HDL) cholesterol, but lower blood pressure, HbA(1c), HOMA-index, and body mass index. Women showed similar associations. Mean IMT for men was significantly lower (P = 0.03) in adiponectin Q4 as compared with Q1 when adjusted for age, waist, smoking, HDL cholesterol, and diastolic blood pressure. When adding HbA1c and HOMA to the model, the association was no longer significant (P = 0.15). In women no difference in IMT was noticed across adiponectin quartiles. Conclusion - Plasma adiponectin is a marker of glucose metabolism and obesity and shows an inverse age-adjusted association with carotid ultrasound IMT in men, but not in women. This association is attenuated after adjustments for other risk factors.