Abstract

Objective: This study examines the association of glycated hemoglobin (HbA1c) with cardiovascular disease risk factors, coronary artery disease (CAD) and metabolic syndrome in Asian Indians with normal glucose tolerance [NGT].

Research design and methods: This cross-sectional study recruited subjects from phase 3 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 1644 subjects with normal glucose tolerance, ie, fasting plasma glucose <100 mg/dl [5.6 mmol/L] and 2 hour post load plasma glucose <140 mg/dl [7.8 mmol/L]. HbA1c was measured using the Biorad Variant machine. Metabolic syndrome was defined based on modified Adult Treatment Panel III (ATP III) guidelines.

Results: The mean (SD) HbA1c value in the study cohort was 5.5%(0.4). HbA1c showed a significant association with body mass index [β=1.640, p<0.001],systolic [β=1.961,p=0.028] diastolic [β=1.474,p=0.017] blood pressure,waist circumference [β=4.983,p<0.001], serum cholesterol [β=0.333,p<0.001], triglycerides [β=0.243, p<0.001], LDL cholesterol [β=0.262,p<0.001], fasting insulin [β=1.500,p<0.001] and homeostasis model assessment (HOMA) insulin resistance [β=0.369,p<0.001] after adjusting for age and gender. Regression analysis showed that HbA1c had a strong association with metabolic syndrome, which persisted after adjusting for age and gender [Odds Ratio (OR):2.9, 95% confidence interval (CI):2.08--4.00,p<0001]. HbA1c also had a strong association with coronary artery disease [OR:2.6, 95% CI:1.23--5.63, p=0.01], but the significance was lost when adjusted for age and gender.

Conclusion: There is a strong association of HbA1c with prevalent cardiovascular disease risk factors in Asian Indians subjects with NGT.