Chronic Obstructive Pulmonary Disease in adults exposed to fine particles from a coal mine fire

IntroductionIn 2014 the Hazelwood open cut coal mine burned for six weeks, exposing nearby residents to fine particulate matter (PM2.5). The long-term health consequences are being evaluated as part of the Hazelwood Health Study (HHS). These analyses explore the association between PM2.5 and chronic obstructive pulmonary disease (COPD).MethodsA sample of 346 exposed, and 173 unexposed, adults participated in the longitudinal Respiratory Stream of the HHS. 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 modelled. Multivariate linear regression and logistic models were fitted to analyse associations between mean and peak PM2.5 exposure and clinical outcomes, stratified by smoking status.ResultsA 10 μg/m3 increase in mean PM2.5 exposure was associated with a 69% (95%CI: 11% to 158%) increase in odds of spirometry consistent with COPD amongst non-smokers and increased odds of chest tightness (odds ratio; OR 1.30, 95%CI 1.03 to 1.64) and chronic cough (OR 1.24, 95%CI 1.02 to 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 to 3.65).DiscussionAlmost four years after a six-week period of coal fire PM2.5 exposure, we identified a dose-response association between exposure and COPD in non-smokers. With climate change a likely contributor to increased risk of landscape fires, the findings will inform policy decisions during future sustained smoke events.KEY MESSAGESWhat is the key question?Are there long-term impacts of a six-week mine fire event generating PM2.5 on COPD and related respiratory symptoms in adults?What is the bottom line?Almost 4 years after the mine fire, each 10 µg/m3 increase in PM2.5 exposure was associated with a 69% increase in odds of spirometry consistent with COPD amongst non-smokers, and a 30% increase in odds of chest tightness and 24% increase in odds of chronic cough amongst all participants. Amongst smokers, each 10 µg/m3 increase in PM2.5 was associated with a 113% increase in odds of chronic cough.Why read on?With the recent megafires in Australia and the United States exposing communities to smoke for weeks to months, evidence of the long-term health impacts of similar duration PM2.5 generating pollution events are needed to inform the public health response.