Insulin sensitivity, insulin secretion, and glucose tolerance versus intima-media thickness in nondiabetic...

To study the association between insulin sensitivity and secretion vs. early manifestations of atherosclerosis, we performed a 5-yr prospective study in 84 nondiabetic, postmenopausal women, aged 58.7 +/- 0.4 yr (mean +/- SD). Insulin sensitivity was measured with the euglycemic, hyperinsulinemic clamp, and insulin secretion was measured as the acute response to iv arginine (5 g). Early atherosclerosis was studied by ultrasonography of the right carotid artery. Mean intima-media thickness (IMT), determined 1 cm proximal to the bifurcation, was 0.81 +/- 0.14 mm at baseline and increased by 0.012 +/- 0.014 mm/yr over the 5 yr (P < 0.001). The maximal IMT, determined in the carotid bifurcation, was 1.42 +/- 0.42 mm at baseline and increased by 0.035 +/- 0.049 mm/yr (P < 0.001). Neither basal IMT nor the increase in mean or maximal IMT correlated to insulin sensitivity or secretion. In contrast, both baseline IMT and the progression in IMT over the 5-yr follow-up (both mean common carotid artery IMT and maximal bifurcation IMT) correlated with systolic blood pressure and low-density lipoprotein cholesterol. We conclude that carotid intima-media thickness is not related to insulin sensitivity or secretion in nondiabetic, postmenopausal women. Instead, the strongest association is seen with systolic blood pressure and low-density lipoprotein cholesterol levels.