Lung function changes in children exposed to mine fire smoke in infancy

Background and ObjectiveChronic, low-intensity air pollution exposure has been consistently associated with reduced lung function throughout childhood. However, there is limited research regarding the implications of acute, high-intensity air pollution exposure. We aimed to determine whether there were any associations between early life exposure to such an episode and lung growth trajectories.MethodsWe conducted a prospective cohort study of children who lived in the vicinity of the Hazelwood coalmine fire. Lung function was measured using respiratory oscillometry. Z-scores were calculated for resistance (R5) and reactance at 5 Hz (X5) and area under the reactance curve (AX). Two sets of analyses were conducted: (i) linear regression to assess the cross-sectional relationship between post-natal exposure to mine fire-related particulate matter with an aerodynamic diameter of less than 2.5 micrometres (PM2.5) and lung function at the 7-year follow-up and (ii) linear mixed-effects models to determine whether there was any association between exposure and changes in lung function between the 3- and 7-year follow-ups.ResultsThere were no associations between mine fire-related PM2.5 and any of the lung function measures, 7-years later. There were moderate improvements in X5 (beta: -0.37 [-0.64, -0.10] p = 0.009) and AX (beta: -0.40 [-0.72, -0.08] p = 0.014), between the 3- and 7-year follow-ups that were associated with mean PM2.5, in the unadjusted and covariance-adjusted models. Similar trends were observed with maximum PM2.5.ConclusionThere was a moderate improvement in lung stiffness of children exposed to PM2.5 from a local coalmine fire in infancy, consistent with an early deficit in lung function at 3-years after the fire that had resolved by 7-years. The Hazelwood coalmine fire (Victoria, Australia) was an extreme air pollution episode that lasted for 6-weeks leading to community concerns regarding the potential health effects. We found no evidence of ongoing lung function changes in children exposed in infancy. Previously reported deficits in lung function appeared to have resolved over time.image