Abstract
Background Understanding of the role of ethnicity and socioeconomic position in the risk of developing SARS-CoV-2 infection is limited. We investigated this in the UK Biobank study.
Methods The UK Biobank study recruited 40-70 year olds in 2006-2010 from the general population, collecting information about self-defined ethnicity and socioeconomic variables (including Townsend deprivation index and educational attainment). SARS-CoV-2 test results from Public Health England were linked to baseline UK Biobank data. Poisson regression with robust standard errors was used to assess risk ratios (RRs) between the exposures and dichotomous variables for: being tested, having a positive test and testing positive in hospital. We also investigated whether ethnicity and socioeconomic position were associated with having a positive test amongst those tested. We adjusted for covariates including age, sex, social variables (including healthcare work and household size), behavioural risk factors and baseline health.
Findings Among 428,225 participants, 1,474 had been tested and 669 had tested positive between 16 March and 13 April 2020. Black, south Asian and white Irish people were more likely to have confirmed infection (RR 4.01 (95%CI 2.92-5.12); RR 2.11 (95%CI 1.43-3.10); and RR 1.60 (95% CI 1.08-2.38) respectively) and were more likely to be hospitalised compared to White British. While they were more likely to be tested, they were also more likely to test positive. Adjustment for baseline health and behavioural risk factors led to little change, with only modest attenuation when accounting for socioeconomic variables. Area socioeconomic deprivation and having no qualifications were consistently associated with a higher risk of confirmed infection (RR 1.91 (95%CI 1.53-2.38); and RR 2.26 (95%CI 1.76-2.90) respectively).
Interpretation Some minority ethnic groups have a higher risk of confirmed SARS-CoV-2 infection in the UK Biobank study which was not accounted for by differences in socioeconomic conditions, measured baseline health or behavioural risk factors. An urgent response to addressing these elevated risks is required.
Funding Medical Research Council, Chief Scientist Office.
Evidence before the study Previous pandemics have often affected specific ethnic and socioeconomically disadvantaged groups disproportionately. We searched the Cochrane COVID-19 study register, the National Library of Medicine’s LITCOVID database, medrxiv and biorxiv for epidemiological studies of the predictors of developing SARS-CoV-2 infection and prognosis of COVID-19 disease on 13th April 2020. A pre-publication ecological study of US counties suggested areas which had higher socioeconomic disadvantage and higher ethnic minorities tended to have greater COVID-19 case fatality. Audit data from critical care units in the UK and administrative data from the US Centers for Disease Control and Prevention found a higher than expected proportion of ethnic minorities were diagnosed with SARS-CoV-2 infection. However, we found no previous studies which accounted for potential differences in previous health, behavioural risk factors or social circumstances. We found a lack of studies examining differences in risk of SARS-CoV-2 infection or prognosis across socioeconomic groups.
Added value of the study In a large population-based cohort study in the UK, we found an increased risk of developing confirmed SARS-CoV-2 infection in Black, South Asian and White Irish ethnic groups. The risk of confirmed infection was also higher with socioeconomic disadvantage (as assessed by both Townsend deprivation quartile and education level). Adjustment for potential confounding and mediating variables did not fully account for the differences in risk for either ethnicity or socioeconomic position. We also investigated whether differences in testing practice could be responsible for these findings (because of differential ascertainment) but found no evidence of this.
Implications of all the available evidence There is increasing evidence that some ethnic minority groups (particularly Blacks, South Asians and White Irish) experience increased risk of SARS-CoV-2 infection, with increased risk amongst more socioeconomically disadvantaged groups too. While socioeconomic position, country of birth, behavioural risk factors and prior health might account for some of the differences between ethnic groups, they do not fully explain this risk.
Policy interventions designed to contain transmission and shield high risk groups need to take account of the higher risk SARS-CoV-2 and worse prognosis experienced by specific ethnic groups and more socioeconomically disadvantaged populations. Monitoring the impacts of the pandemic across different social groups is warranted, so that targeted interventions and a responsive policy approach can be pursued. Further research is needed to understand the mechanisms by which these excess risks arise.
Competing Interest Statement
JPP is a member of the UK Biobank Steering Committee. Apart from the funding acknowledged below, we declare no other competing interests.
Funding Statement
CLN acknowledges funding from a Medical Research Council Fellowship (MR/R024774/1). ED and SVK acknowledge funding from the Medical Research Council (MC_UU_12017/13) and Scottish Government Chief Scientist Office (SPHSU13). SVK also acknowledges funding from a NRS Senior Clinical Fellowship (SCAF/15/02).
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