Respiratory and atopic conditions in children two to four years after the 2014 Hazelwood coalmine fire

Objective To evaluate associations between exposure during early life to mine fire smoke and parent‐reported indicators of respiratory and atopic illness 2–4 years later. Design, setting The Hazelwood coalmine fire exposed a regional Australian community to markedly increased air pollution during February – March 2014. During June 2016 – October 2018 we conducted a prospective cohort study of children from the Latrobe Valley. Participants Seventy‐nine children exposed to smoke in utero, 81 exposed during early childhood (0–2 years of age), and 129 children conceived after the fire (ie, unexposed). Exposure Individualised mean daily and peak 24‐hour fire‐attributable fine particulate matter (PM2.5) exposure during the fire period, based on modelled air quality and time‐activity data. Main outcome measures Parent‐reported symptoms, medications use, and contacts with medical professionals, collected in monthly online diaries for 29 months, 2–4 years after the fire. Results In the in utero exposure analysis (2678 monthly diaries for 160 children exposed in utero or unexposed), each 10 μg/m3 increase in mean daily PM2.5 exposure was associated with increased reports of runny nose/cough (relative risk [RR], 1.09; 95% CI, 1.02–1.17), wheeze (RR, 1.56; 95% CI, 1.18–2.07), seeking health professional advice (RR, 1.17; 95% CI 1.06–1.29), and doctor diagnoses of upper respiratory tract infections, cold or flu (RR, 1.35; 95% CI, 1.14–1.60). Associations with peak 24‐hour PM2.5 exposure were similar. In the early childhood exposure analysis (3290 diaries for 210 children exposed during early childhood, or unexposed), each 100 μg/m3 increase in peak 24‐hour PM2.5 exposure was associated with increased use of asthma inhalers (RR, 1.26; 95% CI, 1.01–1.58). Conclusions Exposure to mine fire smoke in utero was associated with increased reports by parents of respiratory infections and wheeze in their children 2–4 years later.