Beschreibung:
<jats:sec><jats:title>Background</jats:title><jats:p>Infections are considered as leading causes of acute exacerbations of chronic obstructive pulmonary disease (COPD). Non-infectious risk factors such as short-term air pollution exposure may play a clinically important role. We sought to estimate the relationship between short-term air pollutant exposure and exacerbations in Canadian adults living with mild to moderate COPD.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>In this case-crossover study, exacerbations (‘symptom based’: ≥48 hours of dyspnoea/sputum volume/purulence; ‘event based’: ‘symptom based’ plus requiring antibiotics/corticosteroids or healthcare use) were collected prospectively from 449 participants with spirometry-confirmed COPD within the Canadian Cohort Obstructive Lung Disease. Daily nitrogen dioxide (NO<jats:sub>2</jats:sub>), fine particulate matter (PM<jats:sub>2.5</jats:sub>), ground-level ozone (O<jats:sub>3</jats:sub>), composite of NO<jats:sub>2</jats:sub>and O<jats:sub>3</jats:sub>(O<jats:sub>x</jats:sub>), mean temperature and relative humidity estimates were obtained from national databases. Time-stratified sampling of hazard and control periods on day ‘0’ (day-of-event) and Lags (‘−1’ to ‘−6’) were compared by fitting generalised estimating equation models. All data were dichotomised into ‘warm’ (May–October) and ‘cool’ (November–April) seasons. ORs and 95% CIs were estimated per IQR increase in pollutant concentrations.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Increased warm season ambient concentration of NO<jats:sub>2</jats:sub>was associated with symptom-based exacerbations on Lag−3 (1.14 (1.01 to 1.29), per IQR), and increased cool season ambient PM<jats:sub>2.5</jats:sub>was associated with symptom-based exacerbations on Lag−1 (1.11 (1.03 to 1.20), per IQR). There was a negative association between warm season ambient O<jats:sub>3</jats:sub>and symptom-based events on Lag−3 (0.73 (0.52 to 1.00), per IQR).</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>Short-term ambient NO<jats:sub>2</jats:sub>and PM<jats:sub>2.5</jats:sub>exposure were associated with increased odds of exacerbations in Canadians with mild to moderate COPD, further heightening the awareness of non-infectious triggers of COPD exacerbations.</jats:p></jats:sec>