Abstract P384: Hemoglobin A1c and Progression of Coronary Artery Calcification: The Coronary Artery Risk Development in Young Adults (CARDIA) Study
Background: Hemoglobin A1c (HbA1c) is associated with an increased risk of coronary heart disease among individuals without diabetes. However, findings for an association between HbA1c and subclinical atherosclerosis among individuals without diabetes have been mixed. This study assessed the association of HbA1c with progression of coronary artery calcification (CAC) in a biracial cohort of middle-aged men and women without a history of diabetes in the Coronary Artery Risk Development in Young Adults (CARDIA) Study.
Methods: This study included 2098 CARDIA participants who did not have a history of diabetes, had HbA1c measured at the year 20 examination (2005-06), and had CAC measured at the year 20 and 25 examinations (2010-11). CAC was measured using non-contrast cardiac CT with a central reading center. Progression of CAC was defined as a change greater than 0 (i.e., from 0 to positive or from positive to more positive) in the Agatston score between the year 20 and 25 examinations. Because the outcome was common, modified Poisson regression was used to obtain risk ratios (RR) and 95% confidence intervals (CI) to assess the association between HbA1c and CAC progression.
Results: The mean HbA1c at the year 20 exam was 5.3% (range 4.1-6.4%). During the 5 year follow-up period, 529 (25.2%) participants experienced CAC progression. In overall analyses adjusted for age, sex, race, and education, higher HbA1c was associated with CAC progression (Table). This association was attenuated and no longer statistically significant after additional adjustment for cardiovascular risk factors. Effect measure modification by race and sex was investigated but was not statistically significant.
Conclusions: The association of HbA1c with CAC progression among individuals without diabetes may be mediated through established cardiovascular risk factors. Further research is needed to explore the associations, if any, of HbA1c with other markers of subclinical atherosclerosis.
- © 2013 by American Heart Association, Inc.