Chronic Obstructive Pulmonary Disease in Adults Exposed to Fine Particles from a Coal Mine Fire

Abstract

Introduction. In 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 PM 2.5 and chronic obstructive pulmonary disease (COPD).Methods. A 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.Results. A 10 μg/m 3 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).Discussion. Almost four years after a six-week period of coal fire PM2.5 exposure, we identified a doseresponse 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/m 3 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/m 3 increase in PM 2.5 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.

Long-term effects of a coalmine fire on hospital and ambulance use: an interrupted time series study

“…The one exception was the fire-related PM 2.5 model, in which we detected increases in emergency presentations overall and among women and younger persons. Previous Hazelwood Health Study analyses consistently found long-term increases in respiratory symptoms (29,40,41), as well as medium-term increases in emergency department presentations for respiratory conditions (13,14) and poorer lung function in relation to smoke exposure (42). However, recent analysis suggests that the effects on lung function have attenuated over time (43), possibly indicating recovery.…”

Long‐term effects of extreme smoke exposure on COVID‐19: A cohort study

“…The stronger and occasionally significant associations between PM 2.5 and symptom identified COVID‐19 cases could be due to cough being an outcome of both PM 2.5 exposure and COVID‐19 22–24 . Participants whose cough increased due to the coalmine fire would therefore be at higher risk of misclassification of COVID‐19, resulting in an artificial association with PM 2.5 .…”

“…Symptom‐identified cases were based on a standardized rubric that identified likely COVID‐19 cases based on a set of symptoms experienced in 2020, 2021 and each month in 2022, and participant demographics 21,22 . While the symptom‐based rubric was used to identify undiagnosed and unreported cases, there was a potential for misclassification due to one of the symptoms, cough, also being an outcome of PM 2.5 exposure 23,24 ; the implications are covered in the Discussion. More information about the COVID‐19 indicators can be found in Appendix S1 in the Supporting Information.…”

Does diet quality moderate the long-term effects of discrete but extreme PM2.5exposure on respiratory symptoms? A study of the Hazelwood coalmine fire

“…and chronic cough and current wheeze up to 8.5 to 9 years after mine fire [9]. Between 3.5 to 4 years after the mine fire dose-response relationships were observed between PM2.5 and spirometry consistent with chronic obstructive pulmonary disease (COPD) in adult non-smokers [10].…”