Workplace Racial Segregation, Job Mobility, and Cardiovascular Disease Mortality Among Black US Autoworkers

BACKGROUND: Research on the health impacts of segregation in nonresidential spaces, such as the workplace, is limited. Racial discrimination in the work environment can hinder career advancement (job mobility) and exacerbate socioeconomic risk factors of cardiovascular disease (CVD). Using a cohort of manufacturing workers in Detroit, we assessed the relationship between Black-White workplace racial segregation and CVD mortality risk. We considered job mobility as a potential modifier among Black workers from the United Autoworkers-General Motors cohort. METHODS: This retrospective cohort study included 5047 Black workers employed for at least 3 years, with follow-up from 1941 to 2015. Annual segregation exposure was cumulated over working life and divided by time since hire. Job mobility was calculated using each worker's time-varying cumulative area under the curve of their movement between lower and higher-wage jobs. Cox models estimated the impact of segregation and job mobility on CVD mortality. We fit penalized splines to examine the shape of the relationship between segregation and CVD mortality. RESULTS: The average exposure to racial segregation was 13%. We observed a strong positive association between greater workplace racial segregation and CVD mortality, with a hazard ratio of 1.61 (95% CI, 1.18-2.19) in the highest exposure category compared with the lowest. Among workers with lower job mobility, those with moderate or high segregation exposure had increased CVD risk compared with those with low segregation exposure (moderate hazard ratio, 2.13 [95% CI, 1.63-2.78]; high hazard ratio, 2.04 [95% CI, 1.27-3.28]). Results among Black workers with higher job mobility were similar. CONCLUSIONS: Our findings provide evidence that increasing workplace Black-White segregation may increase CVD mortality among Black workers. We observed that the cardiovascular harm of racial segregation to Black workers operates in the workplace regardless of job mobility to positions with higher wages.