Name: Elizabeth Selvin
Department: Epidemiology
Mentor: Josef Coresh
Title of Project: Glycemic Control and Coronary Heart Disease Risk in Persons with and without Diabetes: The Atherosclerosis Risk in Communities Study
Abstract:
Background: Chronic hyperglycemia has been hypothesized to contribute to coronary heart disease (CHD), but the extent to which hemoglobin A1c (HbA1c), a marker of long-term glycemic control, is independently related to CHD risk is uncertain.
Methods: We conducted a prospective case-cohort study of 1321 non-diabetic adults and a cohort study of 1626 diabetic adults from the Atherosclerosis Risk in Communities Study. Using proportional hazards models, we assessed the relation between HbA1c and incident CHD during 8-10 years of follow-up.
Results: In diabetic adults, the relative risk (RR) of CHD was 2.37 (95%CI 1.50, 3.72) for the highest quintile of HbA1c compared to the lowest after adjustment for CHD risk factors. In persons without diabetes, the fully-adjusted RR of CHD in the highest quintile of HbA1c was 1.41 (95%CI 0.90, 2.30); however, there was evidence of a non-linear relationship in this group. In non-diabetic adults, HbA1c was not related to CHD risk below an HbA1c level of 4.6% but strongly related to risk above that level (p<0.01). In diabetic adults, the risk of CHD increased throughout the range of HbA1c. In a fully adjusted model, the RR of CHD for a 1-percentage point increase in HbA1c was 2.36 (95%CI 1.43, 3.90) in persons without diabetes but an HbA1c > 4.6%. In diabetic adults, the RR was 1.14 (95%CI 1.07, 1.21) per 1-percentage point increase in HbA¬1c across the full range of HbA1c values.
Conclusions: Elevated HbA1c is an independent risk factor for CHD in persons with and without diabetes.
