Rationale: In 2014, the Hazelwood open-cut coal mine in southeastern Australia burned for 6 weeks, exposing nearby residents to high concentrations of fine particulate matter (PM2.5). The long-term health consequences are unknown and are being evaluated as part of the Hazelwood Health Study. Objectives: To explore the association between PM2.5 exposure and chronic obstructive pulmonary disease (COPD). Methods: A sample of 346 exposed and 173 unexposed adults participated in the longitudinal Respiratory Stream of the Hazelwood Health Study. Participants underwent spirometry and gas transfer measurements and answered validated respiratory questionnaires 3.5-4 years after the fire. Individual-level mine fire-related PM2.5 exposure was modeled. Multivariate linear regression and logistic models were fitted to analyze associations between mean and peak PM2.5 exposure and clinical outcomes, stratified by smoking status. Results: A 10 μg/m3 increase in mean PM2.5 exposure was associated with a 69% (95% confidence interval [CI], 11-158%) increase in odds of spirometry consistent with COPD among nonsmokers and increased odds of chest tightness (odds ratio [OR], 1.30; 95% CI, 1.03-1.64) and chronic cough (OR, 1.24; 95% CI, 1.02-1.51) in the previous 12 months in all participants. For current smokers, increments in mean PM2.5 exposure were associated with higher odds of chronic cough in the preceding 12 months (OR, 2.13; 95% CI, 1.24-3.65). Conclusions: Almost 4 years after a 6-week period of coal fire PM2.5 exposure, we identified a dose-response association between exposure and COPD in nonsmokers. With climate change a likely contributor to increased risk of landscape fires, the findings will inform policy decisions during future sustained smoke events.
Keywords: cough; environmental exposure; obstructive lung diseases; particulate matter; spirometry.