Risk factors for positive and negative COVID-19 tests: a cautious and in-depth analysis of UK biobank data

Int J Epidemiol. 2020 Oct 1;49(5):1454-1467. doi: 10.1093/ije/dyaa134.


Background: The recent COVID-19 outbreak has generated an unprecedented public health crisis, with millions of infections and hundreds of thousands of deaths worldwide. Using hospital-based or mortality data, several COVID-19 risk factors have been identified, but these may be confounded or biased.

Methods: Using SARS-CoV-2 infection test data (n = 4509 tests; 1325 positive) from Public Health England, linked to the UK Biobank study, we explored the contribution of demographic, social, health risk, medical and environmental factors to COVID-19 risk. We used multivariable and penalized logistic regression models for the risk of (i) being tested, (ii) testing positive/negative in the study population and, adopting a test negative design, (iii) the risk of testing positive within the tested population.

Results: In the fully adjusted model, variables independently associated with the risk of being tested for COVID-19 with odds ratio >1.05 were: male sex; Black ethnicity; social disadvantage (as measured by education, housing and income); occupation (healthcare worker, retired, unemployed); ever smoker; severely obese; comorbidities; and greater exposure to particulate matter (PM) 2.5 absorbance. Of these, only male sex, non-White ethnicity and lower educational attainment, and none of the comorbidities or health risk factors, were associated with testing positive among tested individuals.

Conclusions: We adopted a careful and exhaustive approach within a large population-based cohort, which enabled us to triangulate evidence linking male sex, lower educational attainment and non-White ethnicity with the risk of COVID-19. The elucidation of the joint and independent effects of these factors is a high-priority area for further research to inform on the natural history of COVID-19.

Keywords: COVID-19; SARS-CoV-2; UK Biobank; infection; prospective cohort; test data.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biological Specimen Banks / standards
  • Biological Specimen Banks / statistics & numerical data
  • COVID-19 Testing* / methods
  • COVID-19 Testing* / statistics & numerical data
  • COVID-19* / diagnosis
  • COVID-19* / epidemiology
  • COVID-19* / prevention & control
  • Confounding Factors, Epidemiologic*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Risk Assessment / methods
  • Risk Factors
  • SARS-CoV-2 / isolation & purification
  • United Kingdom / epidemiology