Did in-person work contribute to racial disparities in COVID-19 mortality? Evidence from a mediation analysis using case–control and population-based cohort designs

Abstract We examined whether physical presence at the workplace contributed to racial disparities in COVID-19 mortality among working-age Californians. Using a case–control design, we compared all COVID-19 deaths (n = 4838) and non-COVID-19 deaths (n = 21 453) in California between January 2020 and March 2021, among decedents aged 18-64 confirmed to be working based on employment records. Workplace presence was defined by occupation using a job-exposure matrix. Logistic regression assessed links between racial/ethnic identity, workplace presence, and COVID-19 mortality. These associations were also evaluated in a population-based cohort using Current Population Survey data. Mediation analysis was conducted using the CAUSALMED procedure. Black, Indigenous, and other People of Color (BIPOC) had 39% higher odds of working in roles requiring physical presence compared to white workers (OR = 1.39, 95% CI: 1.30-1.49), and over 4 times higher odds of dying from COVID-19 (OR = 4.34, 95% CI: 3.93-4.79). Physical presence increased COVID-19 mortality risk (OR = 1.22, 95% CI: 1.11-1.33) but did not meaningfully mediate the relationship between BIPOC status and mortality (natural direct effect: OR = 4.29, 95% CI: 3.87-4.73; natural indirect effect: OR = 1.01, 95% CI: 1.00-1.02). Findings highlight occupational segregation and the elevated risks faced by essential workers but suggest that racial disparities in mortality are largely driven by structural factors beyond exposure opportunities associated with physical presence at the workplace.