Prediction of Cardiovascular Disease in Individuals Aged Over 40 Years According to Fasting and Postchallenge Glycemia: Tehran Lipid and Glucose Study

Hyperglycemia is a known a risk factor for cardiovascular disease (CVD), including coronary heart disease (CHD) and stroke. This risk is continuous and graded across the distributions of fasting plasma glucose (FPG), and levels of plasma glucose after an oral glucose challenge. Both fasting and 2-h postchallenge glucose (2hpg) levels contribute to average glycemia, but the relative contributions of fasting and postchallenge hyperglycemia to CVD risk remain uncertain. Considering the high prevalence of cardiovascular disease (CVD) in Tehran, this study was designed to evaluate the effects of difference levels of fasting and postchallenge hyperglycemia in prediction of cardiovascular disease. In this cohort study, all participants of the Tehran Lipid And Glucose Study (TLGS) (3694 subjects), aged over 40years, free from clinical CVD (coronary heart disease, stroke) or medication-treated diabetes were assessed for prediction of incident CVD events. We used the interquartile range (IQR) as a unit of exposure for continuously distributed glycemic measures in predicting CVD risk. Also, the Framingham Risk Score (FRS) was determined in this population at baseline. We recorded the cardiovascular events in 6.1±0.6 years of follow up for all subjects. Finally, we assessed ability of fasting and postchallenge hyperglycemia in prediction of cardiovascular disease. Mean age of the study population was 53.9 years undiagnosed diabetes in this population was present in 346 (9.3%) of the 346 subjects 172 (49.7%) had 2hPG ≥ 200mg/dL without FHG. There were 148 CVD events. In separate sex- and CVD risk–adjusted models,) hazard ratio (HR) for CVD with fasting plasma glucose (per [14 mg/dL] increase) was 1.15 (95% CI: 1.08–1.22) and HR for CVD per 49 mg/dL increase in 2hPG was 1.23 (95% CI: 1.14–1.33). When modeled together, the HR for FHG decreased to 1.03 (95% CI: 0.93–1.13) and for 2hPG remained significant (95% CI: 1.20, 1.05–1.38). In this study, postchallenge hyperglycemia was an independent risk factor for CVD.