Insulin resistance and intima-media thickness in the carotid and femoral arteries of clinically healthy 58-year-old men. The Atherosclerosis and Insulin Resistance Study (AZR)

Objective. To examine whether insulin resistance was associated with ultrasound-assessed measures of atherosclerosis in men with varying degrees of obesity. Design. A random selection of subjects from the general population were divided into quintiles of a body mass index/blood glucose score that was shown to be a valid and reproducible index of the degree of insulin sensitivity as assessed by the clamp technique. Every fourth man in quintiles 1 and 5 and every 20th man in quintiles 2-4 (in total, 104 men) were selected for an ultrasound examination of the carotid and femoral arteries and a euglycaemic hyperinsulinaemic clamp examination, adjusted for fat-free mass. Setting. A university hospital. Subjects. A total of 104 clinically healthy 58-year-old men of Swedish ancestry. Results. The mean common carotid artery intima-media thickness (IMT), but not the common femoral IMT, correlated significantly with glucose infusion rate (GIR) (r = -0.20, P < 0.05), systolic blood pressure (r = 0.20, P < 0.05), pulse pressure (r = 0.23 P < 0.01), heart rate (r = 0.20, P < 0.05), HDL cholesterol (r = -0.18, P < 0.05), log triglycerides (r = 0.28, P < 0.01), apoA(1) (r = -0.20, P < 0.05), apoB (r = -0.22, P < 0.05) and plasma insulin (r = 0.20, P < 0.05). In a multiple regression, common carotid IMT was independently associated with log triglycerides (<beta> = 0.21, P = 0.031) (R-2 = 8.7%, P = 0.005) Conclusions. Insulin sensitivity, measured with the gold standard euglycaemic hyperinsulinaemic clamp method, showed similar associations with ultrasound-assessed measures of atherosclerosis in the carotid arteries as established cardiovascular risk factors, but only triglycerides and pulse pressure contributed independently to the variability in the common carotid intima-media thickness.