Higher rates of severe COVID-19 in BAME populations remain unexplained

Organisation: Position: Deadline Date: Location:

Higher rates of severe COVID-19 infections in Black, Asian and Minority Ethnic (BAME) populations are not explained by socioeconomic or behavioural factors, cardiovascular disease risk, or by vitamin D status, according to research led by Queen Mary University of London.

The findings suggest that the relationship between COVID-19 infection and ethnicity is complex, and requires more dedicated research to explain the factors driving these patterns.

Growing international reports highlight higher risk of adverse COVID-19 infection in BAME populations. The underlying cause of this ethnicity disease pattern is not known. Variation in cardiovascular disease risk, vitamin D levels, socio-economic, and behavioural factors have been proposed as possible explanations. However, these hypotheses have not been formally studied in existing work.

Investigators from Queen Mary, in collaboration with the Medical Research Council Lifecourse Epidemiology Unit at the University of Southampton, used the comprehensive and unique UK Biobank cohort of over half a million people to investigate the role of a range of socioeconomic, biological, and behavioural factors in determining the ethnicity pattern of severe COVID-19. The dataset included 4,510 UK Biobank participants who were tested for COVID-19 in a hospital setting, of whom 1,326 had a positive test result.

The results demonstrate that BAME ethnicity, male sex, higher body mass index, greater material deprivation, and household overcrowding are independent risk factors for COVID-19. The higher rates of severe COVID-19 in BAME populations was not adequately explained by variations in cardiovascular disease risk, vitamin D levels, socio-economic, or behavioural factors, suggesting that other factors not included in the analysis might underlie these differences.

Dr Zahra Raisi-Estabragh, BHF clinical research training fellow at Queen Mary University of London, led the analysis. She said: “There is increasing concern over the higher rate of poor COVID-19 outcomes in BAME populations. Understanding potential drivers of this relationship is urgently needed to inform public health and research efforts. This work goes some way in addressing some of these pertinent questions.”

Steffen Petersen, professor of cardiovascular medicine at Queen Mary University of London, who supervised the work added: “The results of this analysis suggest that factors which underlie ethnic differences in COVID-19 may not be easily captured. In addition to assessment of the role of biological considerations such as genetics, approaches which more comprehensively assess the complex economic and socio-behavioural differences should now be a priority.”

Nicholas Harvey, professor of rheumatology and clinical epidemiology at the MRC Life-course Epidemiology Unit, University of Southampton, was a key collaborator in the work. He comments: “The detailed participant characterisation in the UK Biobank and the rapid linkage of this data with COVID-19 test results from Public Health England permitted consideration of potential importance of a wide range of exposures.”

The work was also supported by the National Institute for Health Research (NIHR) through the Barts Biomedical Research Centre, NIHR Southampton Biomedical Research Centre, and NIHR Oxford Biomedical Research Centre.

Background: We examined whether the greater severity of coronavirus disease 2019 (COVID-19) amongst men and Black, Asian and Minority Ethnic (BAME) individuals is explained by cardiometabolic, socio-economic or behavioural factors.
Methods: We studied 4510 UK Biobank participants tested for COVID-19 (positive, n = 1326). Multivariate logistic regression models including age, sex and ethnicity were used to test whether addition of (1) cardiometabolic factors [diabetes, hypertension, high cholesterol, prior myocardial infarction, smoking and body mass index (BMI)]; (2) 25(OH)-vitamin D; (3) poor diet; (4) Townsend deprivation score; (5) housing (home type, overcrowding) or (6) behavioural factors (sociability, risk taking) attenuated sex/ethnicity associations with COVID-19 status.
Results: There was over-representation of men and BAME ethnicities in the COVID-19 positive group. BAME individuals had, on average, poorer cardiometabolic profile, lower 25(OH)-vitamin D, greater material deprivation, and were more likely to live in larger households and in flats/apartments. Male sex, BAME ethnicity, higher BMI, higher Townsend deprivation score and household overcrowding were independently associated with significantly greater odds of COVID-19. The pattern of association was consistent for men and women; cardiometabolic, socio-demographic and behavioural factors did not attenuate sex/ethnicity associations.
Conclusions: In this study, sex and ethnicity differential pattern of COVID-19 was not adequately explained by variations in cardiometabolic factors, 25(OH)-vitamin D levels or socio-economic factors. Factors which underlie ethnic differences in COVID-19 may not be easily captured, and so investigation of alternative biological and genetic susceptibilities as well as more comprehensive assessment of the complex economic, social and behavioural differences should be prioritised.

Steffen E Petersen, Nicholas C Harvey, Patricia B Munroe, Mark J Caulfield, Cyrus Cooper, Jackie Cooper, Mae S Bethell, Celeste McCracken, Zahra Raisi-Estabragh


Krithi Ravi at the Southampton General Hospital, University Hospital Southampton NHS Foundation Trust, asks in The Lancet with ethnic disparities in COVID-19 mortality: are comorbidities to blame?

On 2 June, 2020, Public Health England (PHE) reported on the disparities in the risk and outcomes of COVID-19. After adjusting for sex, age, deprivation, and region, people from a Black, Asian, and Minority Ethnic (BAME) background had a higher risk of death from COVID-19 than White British people. This analysis did not adjust for comorbidities, and the PHE report highlighted this to be an important limitation as comorbidities were postulated to be “more commonly seen in some BAME groups”.

PHE refers to a study from the COVID-19 Clinical Information Network (CO-CIN), led by Harrison and colleagues, of the difference in survival from COVID-19 associated with membership of an ethnic group. In this study, once comorbidities were accounted for, there was no difference in COVID-19 mortality between ethnic groups. This initially appears to support PHE’s conclusion that differences in the distribution of comorbidities may account for the increased COVID-19 mortality of BAME patients.

However, in CO-CIN’s analysis of more than 14 000 patients with COVID-19 admitted to UK hospitals, BAME patients were more likely to have diabetes, but less likely to have other comorbidities such as chronic cardiac, pulmonary, kidney, and neurological disease, malignancy, and dementia. In the multivariate analysis of risk factors for COVID-19 mortality, the adjusted hazard ratio for diabetes (1·11) was less than that for chronic cardiac (1·20), pulmonary (1·24), and kidney disease (1·28), and dementia (1·40), and equal to the adjusted hazard ratio for malignancy (1·11).

Furthermore, age was by far the largest contributor to risk of death, with an adjusted hazard ratio of 9·09 for patients aged 70–79 years and 11·72 for those aged 80 years and older, compared with people younger than 50 years. 60·7% of White patients admitted to hospital with COVID-19 were aged 70 years and older, compared with 30·7% of Black, 29·2% of Asian, and 35·2% of Minority Ethnic patients.

As patients from a White ethnic background were more likely to be older and have comorbidities associated with a higher risk of dying from COVID-19, it is very concerning that the case fatality at 30 days after hospital admission for COVID-19 appears to be the same in Black and White patients. The lack of association between ethnicity and COVID-19 mortality after adjustment for comorbidities is not reassuring. This suggests that research into ethnic disparities in COVID-19 mortality must consider social as well as biological factors.


Queen Mary University of London material


Journal of Public Health abstract


The Lancet article

Receive Medical Brief's free weekly e-newsletter

Related Posts

Thank you for subscribing to MedicalBrief

MedicalBrief is Africa’s premier medical news and research weekly newsletter. MedicalBrief is published every Thursday and delivered free of charge by email to over 33 000 health professionals.

Please consider completing the form below. The information you supply is optional and will only be used to compile a demographic profile of our subscribers. Your personal details will never be shared with a third party.

Thank you for taking the time to complete the form.