Abstract P080: The Combined Effect of Low Income and Low Education on Coronary Heart Disease Outcomes in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study

Abstract

Background: Low income (LoINC) and low education (LoED) have both been associated with higher coronary heart disease (CHD) risk, but few studies have examined the combined effects of both LoINC and LoED. Hypothesis: The combination of LoINC and LoED is more strongly associated with incident CHD than either LoINC and LoED, or neither. Methods: REGARDS recruited 30,239 black and white participants aged > 45 years residing in the 48 contiguous US between 2003-2007. Baseline data included telephone interviews and in-home visits, and follow-up was conducted every 6 months to detect potential events with expert adjudication of endpoints based on medical record review. Low income (LoInc) was defined as annual household income <$35,000, and low education (LoEd) was defined as less than a high school education. Income and education were combined into four mutually exclusive exposure groups (noLoInc+noLoEd, noLoInc+LoEd, LoInc+noLoEd ,LoInc+LoEd, ). CHD outcomes were definite or probable myocardial infarction or acute CHD death. We constructed Cox models estimating the hazard ratios (HR) for CHD, sequentially adjusting for sociodemographics, health behaviors, physiologic parameters, access to healthcare, and stress and depression. Because of significant interaction by age (p<0.001), analyses were stratified at age 65. Results: We analyzed 24,461 participants without baseline CHD, with numbers in each income/education group as shown in the Table. LoInc+LoEd was associated with the highest risk of CHD among those aged < 65 years, but not among those >65 years of age. LoEd was associated with higher CHD risk in those age >65 years and LoInc was not, but LoInc was associated with higher CHD risk in those age < 65 years, but LoEd was not. Conclusion: LoInc+LoEd was associated with the highest CHD risk at younger ages, but not at higher ages. Income was more important than education for CHD risk at younger ages, but education was more important than income at older ages.