Hyperinsulinemia and carotid atherosclerosis in hypertensive and control subjects.

ABSTRACT

OBJECTIVE: To analyze the relationships between carotid atherosclerosis measured as intima-media thickness (IMT) and different measures of insulin in a population-based case-control study of men and women. RESEARCH DESIGN AND METHODS: Carotid ultrasonographic measurements and 2-h oral glucose tolerance tests were performed in a random sample of 513 hypertensive subjects, aged 40-59 years, and in 518 age- and sex-matched control subjects. The associations between IMT and the different measures of insulin were analyzed through multiple regression and by insulin quintiles. The independent effect of insulin was estimated after concurrent adjustment for age, obesity, LDL cholesterol, and systolic blood pressure. RESULTS: The most powerful correlates with IMT were LDL cholesterol, age, systolic blood pressure, pack-years of smoking, and of the different insulin parameters, 2-h post-load insulin. In stepwise regression analysis, the independent predictors of the mean IMT were LDL cholesterol, systolic blood pressure, pack-years of smoking, and age (P < 0.0001) after adjustment for the independent predictors. In analysis of variance, no positive association of insulin parameters with IMT was found between the 2-h insulin quintiles after adjustment for the independent variables. The exclusion of diabetic subjects did not change the results. CONCLUSIONS: The present study of a population-based sample of men and women found inconsistent associations between different insulin measures and IMT after adjustment for the independent variables.