Association of glycated hemoglobin with carotid intimal medial thickness in Asian Indians with normal glucose tolerance.

To assess the association of glycated hemoglobin (HbA1c) levels with carotid intimal medial thickness (CIMT) in Asian Indians with normal glucose tolerance (NGT).Subjects with NGT were recruited from the Chennai Urban Rural Epidemiology Study carried out on a representative population of Chennai, South India. All subjects had fasting plasma glucose <100 mg/dl (5.6 mmol/l) and 2-h post load plasma glucose <140 mg/dl (7.8 mmol/l). HbA1c was measured using the Biorad Variant machine. CIMT was measured on the right common carotid artery using high-resolution B-mode ultrasonography.The study group included 1383 NGT subjects, of whom 760 (54.9%) were women. The mean CIMT value in the 1st quartile of HbA1c (<5.2%) was 0.65 and it increased significantly to 0.73 in the last quartile of HbA1c (>5.8) (p<0.001). Regression analysis showed that HbA1c had a strong association with CIMT after adjusting for age, gender, waist circumference, systolic and diastolic blood pressure, LDL cholesterol, serum triglycerides, HOMA-IR and smoking (ß - 0.046, p=0.047).Even among subjects with NGT, there is a significant increase in CIMT with increasing levels of HbA1c, showing the value of using HbA1c for diagnosis of glucose intolerance.