Longitudinal Associations between Income Changes and Incident Cardiovascular Disease: The Atherosclerosis Risk in Communities Study

Abstract

Background Higher income is associated with lower incident cardiovascular disease (CVD). However, there are limited data on the association between changes in income and incident CVD. Methods The Atherosclerosis Risk in Communities (ARIC) study is a prospective cohort of community-dwelling men and women. 8,987 participants (mean age 53±6 years) were categorized based on whether their household income subsequently decreased >50%, increased >50%, or changed less than 50% (“unchanged”) over a mean period of 6.0±0.3 years between ARIC visit 1 and 3. We measured incidence of CVD post visit 3 as a composite of definite or probable myocardial infarction (MI), fatal coronary heart disease (CHD), incident heart failure (HF), or definite or probable stroke. This composite outcome and its components were observed over 17±7 years and were related to income changes using Cox regression, adjusted for baseline socio-demographic variables, health behaviors, and biomarkers. Results 900 participants (10%) were classified as having an income drop, 6,282 participants (70%) unchanged, and 1,805 participants (20%) as having an income rise. After adjustment, those with an income drop experienced significantly higher risk of incident CVD compared to those whose income remained unchanged (HR=1.16; 95% CI 1.03, 1.32). This association appeared stronger in whites than in blacks, and was driven primarily by higher risk of MI/fatal CHD (HR=1.28; 95% CI 1.06, 1.55), and stroke (HR=1.32; 95% CI 1.05, 1.67). After adjustment, those with an income rise experienced significantly lower risk of incident CVD compared to those whose income remained unchanged (HR=0.86; 95% CI 0.77, 0.96). This association was driven primarily by lower risk of HF (HR=0.83; 95% CI 0.72, 0.96). Conclusions In a population of middle-aged adults, an income drop was associated with 16% higher risk of incident CVD, while an income rise was associated with 14% lower risk of incident CVD.