Impact of increasing workforce racial diversity on black-white disparities in cardiovascular disease mortality

Background Structural racism’s influence on workforce policies and practices presents possible upstream targets for assessing and reducing racial health disparities. This study is the first to examine workforce racial diversity in association with racial disparities in cardiovascular disease (CVD) outcomes. Methods This retrospective cohort study of 39 693 hourly autoworkers from three Michigan automobile plants, includes 75 years of follow-up (1941–2015). Workforce racial diversity (per cent black autoworkers) was a plant and year level variable. Annual exposure was cumulated over each individual’s working life and divided by time since hire. This time-varying measure was categorised into low, moderate and high. We estimated age-standardised rates of CVD and Cox proportional HRs by race. Results CVD mortality per 100 000 person-years decreased among autoworkers over the study period; however, black workers’ rates remained higher than white workers. Among black workers, we observed a strong protective association between greater workforce racial diversity and CVD mortality. For example, at the Detroit plant, the HR for moderate exposure to racial diversity was 0.94 (0.83, 1.08) and dropped to 0.78 (0.67, 0.90) at the highest level. Among white workers, results were mixed by plant, with protective effects in plants where less than 20% of workers were black and null results where black workers became the majority. Conclusion Our findings provide evidence that workplace racial diversity may reduce CVD mortality risk among black workers. Workplace practices encouraging diverse hiring and retention have potential to improve all workers’ health; particularly the socially racialised groups in that workforce. Data are available upon reasonable request. Data are available upon reasonable request, with limitations to preserve the autonomy and the rights of the individual participants.