Insulin clearance is associated with carotid artery intima-media thickness

OBJECTIVE: The aim of this study was to investigate whether insulin clearance is independently associated with carotid artery intima-media thickness (IMT), a well-recognized index of vascular damage. METHODS: 361 Non-diabetic Caucasian subjects were subjected to euglycemic hyperinsulinemic clamp to assess insulin sensitivity, and insulin clearance. IMT of the common carotid was measured by ultrasonography. RESULTS: Among the study group, 270 subjects had normal glucose tolerance, 33 had impaired fasting glucose, and 58 had impaired glucose tolerance. Univariate correlations showed that age, BMI, waist, blood pressure, triglycerides, fasting and 2-h post-load glucose and insulin levels were positively correlated with carotid IMT whereas HDL, insulin clearance, and insulin-stimulated glucose disposal were negatively correlated with IMT. A multivariate regression analysis in a model including, in addition to insulin clearance, age, gender, BMI, waist, blood pressure, triglycerides, HDL, fasting and 2-h post-load glucose, insulin-stimulated glucose disposal, fasting and 2-h post-load insulin showed that the traits independently associated with carotid IMT were BMI (β = 0.42, P < 0.0001), insulin clearance (β = -0.29, P < 0.0001), age (β = 0.19, P < 0.0001), waist (β = 0.18, P = 0.01), diastolic blood pressure (β = 0.17, P = 0.01), and 2-h post-load glucose (β = 0.12, P = 0.03). These factors explained 26% of the variance in carotid IMT. Subjects in the lowest tertile of insulin clearance had a 4.06-fold higher odds of having vascular damage (IMT > 0.9 mm) as compared with those in the highest tertile (OR 4.06, 95%CI 1.15-13.24). CONCLUSIONS: Insulin clearance is independently associated with carotid IMT in adult non-diabetic subjects. Individuals with lower levels of insulin clearance have a higher odds of vascular damage.