β cell function and insulin resistance have gender-specific correlations with carotid intima-media thickness in type 2 diabetes

The relationships between carotid intima-media thickness (C-IMT) and β cell function and insulin resistance in patients with type 2 diabetes (T2D) have not been fully elucidated. This study is to investigate whether impaired glucose metabolism is etiologically associated with C-IMT in patients with T2D. The study group consisted of 490 (284 men, 206 women) participants. Venous blood specimens were obtained from all subjects for biochemical profiles after an >8-h overnight fast. C-IMT was measured as the distance between the luminal-intimal leading edge (I-line) and the medial-adventitial leading edge (M-line) on the far wall. Insulin resistance was estimated with the homeostasis model assessment of insulin resistance (HOMA-IR). The acute insulin response to arginine was calculated as the mean of the three plasma insulin levels obtained within 2, 4, and 6 min after the arginine bolus minus the pre-stimulus plasma insulin levels. There was a graded increase in C-IMT values according to tertiles of HOMA-IR in men; the values of C-IMT were significantly decreased across the tertiles of acute insulin and C-peptide responses in women. Multivariate analysis revealed that HOMA-IR and age were positively associated with C-IMT among men participants, and acute insulin response and current smoking were the independent determinants of C-IMT in women. Early insulin response stimulated by arginine is independently associated with C-IMT in women T2D individuals, whereas insulin resistance is positively correlated with C-IMT in men T2D subjects.