Association of A1C With Cardiovascular Disease and Metabolic Syndrome in Asian Indians With Normal Glucose Tolerance

OBJECTIVE — This study examines the association of A1C with cardiovascular disease (CVD) risk factors, coronary artery disease (CAD), and metabolic syndrome in Asian Indians with normal glucose tolerance (NGT). RESEARCHDESIGNANDMETHODS — This cross-sectional study recruited subjects from phase III of the Chennai Urban Rural Epidemiology Study (CURES), an epidemiological study in a representative population of Chennai (formerly Madras) in South India, conducted between January 2003 and June 2004. Included were 1,644 subjects with NGT, i.e., fasting plasma glucose 100 mg/dl (5.6 mmol/l) and 2-h postload plasma glucose 140 mg/dl (7.8 mmol/l). A1C was measured using the Biorad Variant machine. Metabolic syndrome was defined based on modified Adult Treatment Panel III guidelines. RESULTS — The mean SD A1C value in the study cohort was 5.5 0.4%. A1C showed a significant association with BMI ( 0.017, P 0.001), systolic ( 0.002, P 0.028) and diastolic ( 0.202, P 0.017) blood pressure, waist circumference ( 0.007, P 0.001), serum cholesterol ( 0.002, P 0.001), triglycerides ( 0.001, P 0.001), LDL cholesterol ( 0.002, P 0.001), fasting insulin ( 0.009, P 0.001), and homeostasis model assessment of insulin resistance ( 0.047, P 0.001) after adjusting for age and sex. Regres-sion analysis showed that A1C had a strong association with metabolic syndrome that persisted after adjusting for age and sex (odds ratio [OR] 2.9 [95 % CI 2.08–4.00]; P 0.001). A1C also had a strong association with CAD (2.6 [1.23–5.63]; P 0.01), but the significance was lost when adjusted for age and sex. CONCLUSIONS — There is a strong association of A1C with prevalent CVD risk factors in Asian-Indian subjects with NGT