Is asthma associated with exposure to smoke from a coal mine fire?

Abstract

In 2014, a fire at the Hazelwood open cut coal mine (Victoria, Australia) burned for about 6 weeks. Residents of the adjacent town of Morwell were exposed to high levels of fine particulate matter (PM2.5) during this period. Three and a half years after the event, this study aimed to investigate the long-term impact of short-term exposure to coal mine fire smoke on asthma.\n\nA cross-sectional analysis was undertaken on a group of exposed participants with asthma from Morwell (n=165) and a group of unexposed participants with asthma from the control town of Sale (n=64). Town exposure status was determined by modelled PM2.5 data for the mine fire period. Respiratory symptoms were assessed with a validated respiratory health questionnaire and symptom severity score. Asthma control was assessed with an asthma control questionnaire. Lung function testing included spirometry, bronchodilator response, and fraction of exhaled nitric oxide.\n\nThere was no evidence that exposed Morwell participants had more severe asthma symptoms, worse lung function, or more eosinophilic airway inflammation compared to unexposed Sale participants. However there was some evidence that Morwell participants had more uncontrolled than well-controlled asthma, compared to the participants from Sale (adjusted relative risk ratio 2.71 95%CI: 1.02, 7.21, p=0.046).\n\nThree and a half years after exposure, coal mine fire smoke does not appear to be associated with more severe asthma symptoms or worse lung function, but may be associated with poorer asthma control.\n\nSummary take home messageIn people with asthma, short-term coal mine fire smoke exposure does not appear to have long-term impact on severity of asthma symptoms, lung function or eosinophilic airway inflammation, but may affect asthma control.