Impaired Fasting Glucose and Risk of Cardiovascular Disease in Korean Men and Women: The Korean Heart Study

OBJECTIVE: The relationship between impaired fasting glucose (IFG) and risk of cardiovascular disease (CVD) or ischemic heart disease (IHD) varies widely according to sex and ethnicity. We evaluated the relationship between IFG and CVD or IHD among Korean men and women. RESEARCH DESIGN AND METHODS: A total of 408,022 individuals who underwent voluntary private health examinations in 17 centers in South Korea were followed for 10 years. Data regarding CVD or IHD events were obtained from the Korean National Health Insurance database. IFG was categorized as grade 1 (fasting glucose 100–109 mg/dL) or grade 2 (110–125 mg/dL). RESULTS: Incidence rates of CVD (per 100,000 person-years) were 2,203 for diabetes. Age-adjusted hazard ratios (HRs) for CVD were 1.17 (95% CI 1.13–1.20) for grade 1 IFG, 1.30 (1.24–1.35) for grade 2 IFG, and 1.81 (1.75–1.86) for diabetes. The increased risk for women was similar to that of men. Age-adjusted HRs for IHD and ischemic stroke were also significantly increased for men and women with IFG and diabetes. After multivariate adjustment of conventional risk factors (hypertension, dyslipidemia, smoking, obesity, and family history of CVD), the overall risk of CVD was greatly attenuated in all categories. However, the HRs for IHD and ischemic stroke remained significantly increased in men for grade 2 IFG but not in women. CONCLUSIONS: In Korea, grade 2 IFG is associated with increased risk of IHD and ischemic stroke, independent of other conventional risk factors, in men but not in women.