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

Abstract

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 PM2.5 and chronic obstructive pulmonary disease (COPD). 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 modeled. 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. A 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, increased mean PM2.5 exposure was associated with higher odds of chronic cough in the preceding 12 months (OR 2.18, 95%CI 1.28 to 3.71) relative to other participants. More than three 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.

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

“…21 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.…”

“…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][23][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 . However, cough symptoms had the lowest weighting in the rubric, meaning the bias may be marginal at best (for comparison, cough was given a weight of 0.31, while loss of taste/smell, the highest-weighted symptom, was 1.75; see S1.2.1 in the Supporting Information).…”

Respiratory symptoms after coalmine fire and pandemic: a longitudinal analysis of the Hazelwood Health Study adult cohort

“…PM 2.5 during the fire was associated with increased use of respiratory medical services including GP and specialist visits (7), hospital admissions and emergency presentations (8), and dispensing of inhaled medicines (9). There is evidence that effects have persisted for at least a few years, including higher prevalence of respiratory symptoms measured between 2-4 years after the fire (10,11), accelerated lung ageing, features of chronic obstructive pulmonary disease (COPD) at 4 years (11)(12)(13), and increased respiratory emergency department presentations in the five years post-fire (14). Recent findings suggest some recovery in lung function 7.5 years after the fire (15), though the long-term effects remain unclear.…”