Association between long-term exposure to air pollution on the risk of infection by SARS-CoV-2 virus and COVID-19 disease in the French CONSTANCES cohort

Long-term air pollution exposure has been associated with increased risk of SARS-CoV-2 infection. However, few studies have used individual-level data, and even fewer serology data. We aimed to investigate the association between long-term exposure to air pollution and 1) SARS-CoV-2 infection and 2) COVID-19 disease, among adults from the French CONSTANCES population-based cohort. SARS-CoV-2 infection was assessed in May–November 2020 using ELISA test serology; COVID-19 disease was self-reported as medical diagnosis of SARS-CoV-2 infection and associated symptoms. Annual 2019 exposures to particulate matter with an aerodynamic diameter of ≤2.5 (PM2.5), black carbon (BC) and nitrogen dioxide (NO2) were estimated using hybrid land-use regression models and assigned at pre-pandemic residential address. We estimated log-binomial risk ratios (RRs for an interquartile range increase), adjusting for individual and area-level covariates. The population included 33,974 participants, among which 1695 (4.99 %) had a SARS-CoV-2 infection, and 802 (2.8 %) reported COVID-19 disease. Exposure to PM2.5 and NO2 were associated with a higher probability of SARS-CoV-2 infection (Adjusted RRs (aRR[95 %CI]): 1.28[1.10: 1.50] for PM2.5, 1.21[1.07: 1.37] for NO2) and COVID-19 disease (1.41[1.11: 1.79] for PM2.5, 1.40[1.18: 1.66] for NO2). Exposure to BC was associated with a higher probability of COVID-19 disease (1.20[1.03: 1.39]) but not SARS-CoV-2 infection (1.07[0.97–1.19]). Stratified analyses showed higher risks for men, age >60, or having pre-existent chronic disease. Using individual data, long-term exposure to air pollution was associated with increased risks of SARS-CoV-2 infection and COVID-19 disease. These results could help to better understand or prevent respiratory infections.