Early life exposure to coal mine fire smoke emissions and altered lung function in young children

Abstract

Background and objective Long‐term respiratory risks following exposure to relatively short periods of poor air quality early in life are unknown. We aimed to evaluate the association between exposure to a 6‐week episode of air pollution from a coal mine fire in children aged <2 years, and their lung function 3 years after the fire. Methods We conducted a prospective cohort study. Individual exposure to 24‐h average and peak concentrations of particulate matter with an aerodynamic diameter <2.5 μm in diameter (PM2.5) during the fire were estimated using dispersion and chemical transport modelling. Lung function was measured using the forced oscillation technique (FOT), generating standardized Z‐scores for resistance and reactance at a frequency of 5 Hz (Rrs5 and Xrs5), and area under the reactance curve (AX). We used linear regression models to assess the associations between PM2.5 exposure and lung function, adjusted for potential confounders. Results Of the 203 infants originally recruited, 84 aged 4.3 ± 0.5 years completed FOT testing. Median (interquartile range, IQR) for average and peak PM2.5 were 7.9 (6.8–16.8) and 103.4 (60.6–150.7) μg/m3, respectively. The mean ± SD Z‐scores for Rrs5, Xrs5 and AX were 0.56 ± 0.80, –0.76 ± 0.88 and 0.72 ± 0.92, respectively. After adjustment for potential confounders including maternal smoking during pregnancy, a 10 μg/m3 increase in average PM2.5 was significantly associated with worsening AX (β‐coefficient: 0.260; 95% CI: 0.019, 0.502), while the association between a 100‐μg/m3 increase in peak PM2.5 and AX was borderline (0.166; 95% CI: −0.002, 0.334). Conclusion Infant exposure to coal mine fire emissions could be associated with long‐term impairment of lung reactance.

No fire without smoke: Are the children really out of the woods?

“…Paediatricians need to continue to press home this point to politicians and urge strong action; Shao et al . 's study adds to the evidence that we are literally playing with fire if we do not do our utmost to protect little lungs from all outdoor (and indoor) pollutants.…”

“…In a recent publication in Respirology , Shao et al . followed up a cohort of children who were transiently exposed to high levels of atmospheric pollution as a result of serious fires . At 3‐year follow‐up, they demonstrated impairment of peripheral lung mechanics as measured by the forced oscillation technique (FOT).…”

“…As in many real‐world studies, there are data issues that mandate caution in drawing strong conclusions. Follow‐up was incomplete (84/203, 41%), which could have led to an inadvertent selection bias, as discussed by the authors . A comparison of FOT results in infants exposed to the fire with unexposed controls or with those older than 2 years of age during the fire would have added value to the study.…”

“…So, what is the overall message of Shao et al . 's study? Clearly, we know that big fires are not good for anybody, but what the manuscript does stress yet again is the vulnerability of preschool children to environmental insults.…”

Beyond the womb: respiratory symptoms in children following acute in utero exposure to fire smoke

“…These associations were not statistically significant for the 129 children exposed to the fire when 0–2 years old, perhaps because of the small sample size . Data on lung function for a subgroup of the ELF cohort (84 children) published elsewhere indicated that increasing mean daily PM 2.5 exposure was modestly associated with reduced respiratory system reactance (per 10 μg/m 3 increase: β‐coefficient, 0.26; 95% CI, 0.02–0.50) …”