Carotid intima-media thickness in type 2 diabetes is more strongly related to serum apoprotein A-I in females.

BACKGROUND: Dyslipidemia in type 2 diabetes has been shown to be related to the incidence of macrovascular events. Increased carotid intima-media thickness is considered to be a marker of macrovascular disease.

MAIN PURPOSE: To investigate a possible relationship between lipoprotein levels and carotid intima-media thickness as a marker of early atherosclerosis in patients with type 2 diabetes.

METHODS: Seventy-one consecutively selected eligible patients (31 males, 40 females) with type 2 diabetes were studied. Common carotid intima-media thickness was measured bilaterally by high-resolution ultrasound and the mean value from both sides was used for further analysis. Fasting blood samples were taken from each individual and their serum was analyzed for lipoprotein levels.

RESULTS: In the entire group of patients, intima-media thickness was inversely related to apoprotein A-I (r = -0.33, p = 0.008) and HDL cholesterol (r = -0.23, p = 0.059) in univariate correlation analysis, and a positive correlation between intima-media thickness and apoprotein B/apoprotein A-I ratio was found (r = 0.33, p = 0.007). When genders were analyzed separately, intima-media thickness was significantly correlated with apoprotein A-I and apoprotein B/apoprotein A-I ratio in females, while no significant correlation of any lipid variable with intima-media thickness was observed in males. In multiple linear regression analysis, age (p = 0.005), male gender (p = 0.002) and apoprotein A-I (p = 0.035) were the only risk factors in the entire group of diabetic patients, which significantly predicted carotid intima-media thickness in models adjusted for demographic and other known risk factors. As was the case in the univariate analysis, no risk factor significantly predicted carotid intima-media thickness in males while age, apoprotein A-I and B significantly predicted intima-media thickness in females.

CONCLUSIONS: In the present study, low serum apoprotein A-I, a major protein component of HDL, was found to be related to increased carotid intima-media thickness. This relationship was stronger in females than in males, which suggests possible gender differences in the relationship between apoprotein A-1 and early atherosclerotic lesions in subjects with type 2 diabetes mellitus.