Lipoprotein concentrations and carotid atherosclerosis by diabetes status - Results from the Insulin Resistance Atherosclerosis Study

OBJECTIVE - Lipoprotein concentrations are associated with the development of atherosclerosis in people with and without diabetes. The relative strength of these associations could differ by diabetes status as a result of diabetes-related lipoprotein modifications. RESEARCH DESIGN AND METHODS - The associations between lipoprotein concentrations and internal and common carotid artery intimal-medial thickness (IMT) assessed by B-mode ultrasonography were examined by diabetes status in a cross-sectional analysis among 1,391 participants in the Insulin Resistance Atherosclerosis Study. Participants included 442 individuals with type 2 diabetes, 308 with impaired glucose tolerance, and 641 with normal glucose tolerance. RESULTS - The differences in internal and common carotid IMT between the highest and lowest tertiles of LDL were 58.1 mu m (P = 0.054) and 51.0 mu m (P < 0.001), respectively. The differences in internal and common carotid IMT between the lowest and highest tertiles of HDL were 56.2 mu m (P = 0.07) and 37.8 mu m (P = 0.003), respectively. Triglycerides and VLDL were not associated with IMT. These associations did not differ significantly because of diabetes status. CONCLUSIONS - These results support the importance of dyslipidemia as a major risk factor for atherosclerosis in people with diabetes. Future research in humans should measure lipoprotein oxidizability, glycation, size, and composition directly in people of differing glucose tolerance status to address the importance of diabetes-related lipoprotein modifications more conclusively.