TitleAir Pollution as a Risk Factor for Incident COPD and Asthma: 15-Year Population-Based Cohort Study
Publication TypeJournal Article
Year of Publication2020
AuthorsShin, S, Bai, L, Burnett, RT, Kwong, JC, Hystad, P, van Donkelaar, A, Lavigne, E, Weichenthal, S, Copes, R, Martin, RV, Kopp, A, Chen, H
JournalAmerican Journal of Respiratory and Critical Care Medicine
Date Published11/2020

Rationale: Current evidence on the relationship between long-term exposure to air pollution and new onset of chronic lung disease is inconclusive.

Objective: To examine associations of incident chronic obstructive pulmonary disease (COPD) and adult-onset asthma with past exposure to fine particulate matter (PM2.5), nitrogen dioxide (NO2), ozone (O3), and the redox-weighted average of NO2 and O3 (Ox), and characterize the concentration-response relationship.

Methods: We conducted a population-based cohort study of all Ontarians, aged 35 to 85 years, from 2001 to 2015. 3-year moving average of residential exposures to selected pollutants with 1-year lag were estimated during follow-up. We used Cox proportional and Aalen's additive hazards models to quantify the pollution-disease associations, and characterized the shape of these relationships using newly developed non-linear risk models.

Measurements and main results: Among 5.1 million adults, we identified 340,733 and 218,005 incident cases of COPD and asthma, respectively. We found positive associations of COPD with PM2.5 per interquartile-range (IQR) increase of 3.4µg/m3 (hazard ratio, 1.07; 95% confidence interval, 1.06-1.08), NO2 per 13.9ppb (1.04; 1.02-1.05), O3 per 6.3ppb (1.04; 1.03-1.04), and Ox per 4.4ppb (1.03; 1.03-1.03). By contrast, we did not find strong evidence linking these pollutants to adult-onset asthma. Additionally, we quantified that each IQR increase in pollution exposure yielded 3.0 (2.4-3.6) excess cases of COPD per 100,000 adults for PM2.5, 3.2 (2.0-4.3) for NO2, 1.9 (1.3-2.5) for O3, 2.3 (1.7-2.9) for Ox. Furthermore, most pollutant-COPD relationships exhibited supralinear shapes.

Conclusions: Air pollution was associated with higher incidence of COPD, but not adult-onset asthma.

Short TitleAm J Respir Crit Care Med