Lower insulin sensitivity as an independent risk factor for carotid wall thickening in normotensive, non-diabetic, non smoking normal weight and obese premenopausal women

OBJECTIVE: Increased thickness of the intima-media complex of the common carotid artery (IMT-CCA) is an early marker of atherosclerosis. The aim of the present study was to investigate the relationship between insulin resistance and IMT-CCA in premenopausal women. SUBJECTS: 86 young women, aged 18-31 y, were recruited for the study: 28 were normal weight (BMI<25 kg/m2), 23 were overweight (BMI 25-30 kg/m2) and 35 were obese (BMI>30 kg/m2). MEASUREMENTS: The IMT-CCA was measured by high resolution 'B-mode' ultrasonography; insulin sensitivity was determined by insulin tolerance test (ITT) and quantitated by calculation of KITT. Fasting plasma glucose and lipids (triglycerides, total and HDL-cholesterol) were also measured by enzymatic methods. Central fat accumulation was evaluated by measuring waist circumference (WC). RESULTS: IMT-CCA showed an inverse association with KITT (P<0.05). When the IMT-CCA was considered as the dependent variable in a forward stepwise multiple regression analysis, it maintained an independent association with KITT (P<0.05), after adjusting data for age, BMI, WC, mean blood pressure levels and plasma glucose and lipids. CONCLUSION: These results suggest that IMT-CCA is significantly associated with insulin resistance, independent of other well-known CVD risk factors. Since the IMT-CCA is an earlier asymptomatic sign of atherosclerosis, this study indicates that insulin resistance per se may accelerate atherogenesis.