The aim of this study was to investigate whether
insulin resistance is independently associated with early manifestations of
atherosclerosis. To this end, 176 normotensive offspring of type 2 diabetic patients were subjected to euglycemic hyperinsulinemic clamp to assess
insulin sensitivity. Early
atherosclerosis was studied by ultrasonography of the common carotid artery. Of the total 176 subjects, 145 were
glucose tolerant, 18 had impaired fasting
glucose, and 13 had
impaired glucose tolerance. Univariate correlations showed that age, body mass index, waist, blood pressure, 2-h postchallenge
glucose, fasting
insulin,
triglycerides,
interleukin-6,
fibrinogen, and white blood cell count were significantly correlated with carotid intima-media thickness (IMT), whereas
HDL cholesterol and
glucose disposal showed a negative correlation. A stepwise multivariate regression analysis including sex, age, waist circumference, smoking status, systolic blood pressure, diastolic blood pressure,
triglyceride, HDL cholesterol, 2-h postchallenge
glucose, plasma
IL-6,
fibrinogen, white blood cell count,
insulin-stimulated
glucose disposal, and fasting
insulin showed that the four variables that remained significantly associated with carotid IMT were waist circumference,
insulin-stimulated
glucose disposal, white blood cell count, and diastolic blood pressure, accounting for 33.7% of its variation. These findings support the concept that
insulin sensitivity, rather than plasma
insulin levels, is associated with early
atherosclerosis in nondiabetic normotensive offspring of type 2 diabetic patients.