Disparities in cardiovascular disease in black and white Americans: Clinical and non-clinical approaches to risk mitigation in a multi-cohort study

Background: While the greater burden of cardiovascular disease (CVD) in black Americans relative to white has persisted for four decades, mitigation of this disparity via clinical and non-clinical intervention is largely untested. We examined the relative impacts of targeting conventional risk factors (e.g., diabetes) and the social determinants of health (e.g., education). Methods: In this multicohort study, we used baseline ethnicity and risk factor data from the US National Health and Nutrition Examination Survey (NHANES, 10 cohorts initiated 1999-2018) with study member linkage to national registries for cause-specific mortality. Low risk was denoted by individual risk factors and their combination. Cox proportional hazard regression models were used to summarise the association of race/ethnicity with CVD mortality. Results: An analytical sample of 50,065 individuals (25,934 women; mean baseline age 53) contributed 473,949 person-years at risk (mean follow-up 9.5 yr), giving rise to 9118 deaths (2908 from CVD). In age- and sex-adjusted analyses, as anticipated, relative to whites, black Americans had a markedly higher burden of CVD (hazard ratio; 95% confidence interval: 1.51; 1.30, 1.77) and other major causes of mortality. Black Americans classified as low-risk based on individual clinical risk indices (e.g., normotensives: 1.58; 1.22, 2.04) and the Framingham algorithm (2.94; 2.04, 4.25) continued to experience higher rates of CVD relative to white individuals. A marked reduction in this disparity was, however, apparent in black versus white Americans who had one (1.09; 0.78, 1.51), two (0.99; 0.67, 1.48), and three or more (1.31; 0.81, 2.12) favourable social determinants. A similar pattern of results was evident for total mortality. Conclusions: While disparities in CVD continued to be apparent in black people who had achieved treatment targets for clinical and lifestyle factors, those in favourable social circumstances had disease rates similar to white people with the same characteristics.