Long-Term Air Pollution Exposure and Risk of SARS-CoV-2 Infection and COVID-19 Severity: A UK-Wide Cohort Study (COVIDENCE UK)

Abstract

Background: The association between air quality and risk of SARS-CoV-2 infection is poorly understood. We investigated this association using serological individual-level data adjusting for a wide range of confounders, in a large population-based cohort (COVIDENCE UK).

Methods: We assessed the associations between long-term (2015–19) nitrogen dioxide (NO2) and fine particulate matter (PM with an aerodynamic diameter of ≤2.5 µm [PM_2.5]), exposures with SARS-CoV-2 infection, level of antibody response among those infected, and COVID-19 disease severity. We used serological data from 10,489 participants in the COVIDENCE UK cohort, and estimated annual average air pollution exposure at each participant’s home postcode.

Findings: After controlling for potential confounders, we found a positive association between 5-year NO₂ and PM_2.5 exposures and the risk of seropositivity: a per-unit increase in NO2 (μg/m³) was associated with an increasing risk of seropositivity of 0.8% (95% CI 0·2 to 1·5; p-for-trend 0.016). For PM_2.5, a per-unit increase (μg/m³) was associated with an increasing risk of seropositivity of 4.9% (–0·1 to 10·2; p-for-trend 0·051). In addition, we found that NO2 was positively associated with higher antibody titres (p-for-trend 0·013) among seropositive participants, with no evidence of an association for PM_2.5.

Interpretation: Our findings suggest that the long-term burden of air pollution increased the risks of SARS-CoV-2 infection and has important implications for future pandemic preparedness. This evidence strengthens the case for reducing long-term air pollution exposures to reduce the vulnerability of individuals to respiratory viruses.

Funding: NIHR, school of primary care research (SPCR). NIHR ARC North Thames. NIHR Health Protection Research Units in Chemical and Radiation Threats and Hazards and Environmental Exposures and Health, partnerships between Imperial College London and The UK Health Security Agency (UKHSA).Barts Charity (MGU0570, MGU0459, MGU0466).Pharma Nord, the Fischer Family Foundation, DSM Nutritional Products, the Exilarch’s Foundation, the Karl R Pfleger Foundation, the AIM Foundation, Synergy Biologics, Cytoplan, the UK National Institute for Health and Care Research Clinical Research Network (52255; 52257), the Health Data Research UK BREATHE Hub, the UK Research and Innovation Industrial Strategy Challenge Fund (MC_PC_19004), Thornton & Ross, Warburtons, Matthew Isaacs (personal donation), Barbara Boucher (personal donation), and Hyphens Pharma.

Declaration of Interest: AS is a member of the Scottish Government Chief Medical Officer’s COVID-19 Advisory Group and its Standing Committee on Pandemics. He is also a member of the UK Government’s NERVTAG’s Risk Stratification Subgroup. ARM declares receipt of funding in the last 36 months to support vitamin D research from the following companies who manufacture or sell vitamin D supplements: Pharma Nord, DSM Nutritional Products, Thornton & Ross and Hyphens Pharma. He also declares support for attending meetings from the following companies who manufacture or sell vitamin D supplements: Pharma Nord and Abiogen Pharma. He also declares participation on the Data and Safety Monitoring Board for the Chair, DSMB, VITALITY trial (Vitamin D for Adolescents with HIV to reduce musculoskeletal morbidity and immunopathology). He also declares unpaid work as a Programme Committee member for the Vitamin D Workshop. He also declares receipt of vitamin D capsules for clinical trial use from Pharma Nord, Synergy Biologics and Cytoplan. CJG is supported by the NIHR ARC North Thames. All other authors declare that they have no competing interests.

Keywords: air pollution exposure, SARS-CoV-2 infection, UK-wide cohort.