State-level structural racism and incident coronary heart disease

IntroductionBlack Americans have greater coronary heart disease (CHD) burden than White Americans, disparities that are largely socially determined. Discriminatory societal practices that systematically disadvantage Black Americans are forms of structural racism but few studies have examined structural racism and incident CHD. We sought to determine associations between three validated measures of structural racism and incident CHD, hypothesizing that greater state-level structural racism is associated with incident CHD for Black but not White individuals. MethodsWe used data from the national REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort, which enrolled 30,239 Black and White community dwelling adults between 2003-7 who were contacted every 6 months with retrieval of medical records and expert adjudication of myocardial infarction and cause of death. Incident CHD was defined as myocardial infarction or death due to CHD. Structural racism variables included Black:White % living below the Federal poverty line, Black:White % uninsured, and the Dissimilarity Index (DI), a measure of residential racial segregation. Structural racism variables were dichotomized at the median. Separate race-stratified Cox proportional hazards models examined associations between each measure of structural racism and incident CHD. ResultsThe 24,099 participants free of CHD at baseline included 10,286 Black and 13,813 White participants. Mean age at baseline was 64 years, 58% were women, and 47% had annual household income <$35,000. Greater structural racism was significantly associated with incident CHD for Black but not White participants. For high Black:White poverty, Black HR=1.17 (95% CI 1.01-1.35), White HR=0.93 (0.83-1.06); for high Black:White uninsurance, Black=HR 1.34 (1.06-1.70), White HR=1.20 (0.98-1.47); for high DI, Black HR=1.17 (1.01-1.35), White HR=0.99 (0.88-1.12). Findings suggest that structural racism variables indirectly influence CHD via individual-level income and education. Results were similar for men and women and for older and younger individuals. Significant associations were observed for fatal but not nonfatal CHD events. ConclusionsStructural racism was associated with higher incidence of CHD for Black but not White individuals. If these associations are causal, changing state level laws to combat poverty in Black communities, expand Medicaid, and reduce segregation could potentially lessen Black:White disparities in CHD.