Abstract
OBJECTIVE: Individuals with impaired glucose tolerance (IGT) appear to be at increased risk for cardiovascular disease (CVD) due at least in part to an increased prevalence of risk factors. We evaluated lipid, lipoprotein, C-reactive protein (CRP), fibrinogen, and tissue plasminogen activator (tPA) levels at study entry in the largest multiethnic cohort of participants with IGT described, namely in the Diabetes Prevention Program (DPP). RESEARCH DESIGN AND METHODS: Measurements were performed at the baseline visit of 3,819 randomized participants of the DPP. Among 3,622 participants who were not taking lipid-lowering medicines, cardiovascular risk factors were analyzed in relation to demographic, anthropometric, and metabolic measures. Major determinants of risk factors were assessed in multivariate analysis. RESULTS: Over 40% of participants had elevated triglyceride, LDL cholesterol, and CRP levels and reduced HDL cholesterol levels. Men had higher triglyceride and tPA and lower HDL cholesterol concentrations and smaller LDL particle size than women, whereas women had higher CRP and fibrinogen levels. African Americans had less dyslipidemia but higher fibrinogen levels, and Asian Americans had lower CRP and fibrinogen levels than Caucasians and Hispanics. The surrogate measure of insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR]) had the strongest association with HDL cholesterol, triglyceride, and tPA levels and LDL particle size. BMI had the greatest influence on CRP and fibrinogen levels. Using median splits of indexes of insulin resistance and insulin secretion (insulin-to-glucose ratio), participants with greater insulin resistance had a more adverse CVD risk-factor profile, whereas insulin secretion had little influence on risk factors. CONCLUSIONS: The pattern of CVD risk factors in participants with IGT in the DPP exhibits substantial heterogeneity and is significantly influenced by race, sex, and age, as well as by obesity, glucose, and insulin measures. The degree of insulin resistance, as reflected by HOMA-IR, showed the greatest association with the cardiovascular risk factors.