Are ethnic inequalities in COVID-19 outcomes mediated by occupation risk? Analyses of a 2-year record linked national cohort study in Scotland

This study investigated the extent to which ethnic inequalities in severe COVID-19 (i.e. hospitalization or deaths) are mediated through occupational risk differences. We used a population-based cohort study linking the 2011 Scottish Census to health records. We included all individuals aged 30-64 years and living in Scotland on 1 March 2020. The study period was from 1 March 2020 to 17 April 2022. Self-reported ethnicity was taken from the Census. We derived occupational risk of SARS-COV-2 infection using the 3-digit Standard Occupational Classification (SOC2010). We estimated hazard ratios (HRs) of total effects and controlled direct effects of ethnicity on severe COVID-19 mediated by occupational risk using marginal structural Cox models and subsequent proportional change. For aggregated ethnic groups, Non-White groups experienced a higher risk of severe COVID-19 (HR 1.6; 95% CI 1.4-1.8) compared to White group (all White ethnic groups) which increased to (1.7; 1.4-2.1) after accounting for occupational risk, representing a 6.0% change. For disaggregated ethnic groups, risks for South Asian (2.0; 1.8-2.3), African, Caribbean, or Black (1.3; 0.9-1.7) and Other ethnic groups (1.1; 0.9-1.3) were higher compared to White Scottish. After accounting for occupational risk, estimated risk of severe COVID-19 remained elevated for South Asian (1.8; 1.2-2.3), African Caribbean or Black (1.4; 0.8-2.1) and Other ethnic group (1.7; 1.1-2.3) representing a reduction of 11.8% and increases of 16.4% and 59.0%, respectively. Our findings suggest that ethnic inequalities in severe COVID-19 were impacted by differences in occupational risk.