No association between in utero exposure to emissions from a coalmine fire and post-natal lung function

Studies linking early life exposure to air pollution and subsequent impaired lung health have focused on chronic, low-level exposures in urban settings. We aimed to determine whether in utero exposure to an acute, high-intensity air pollution episode impaired lung function 7-years later. We conducted a prospective cohort study of children who lived in the vicinity of a coalmine fire. Respiratory function was measured using the forced oscillation technique (FOT). Z-scores for resistance at 5 Hz (R ), reactance at 5 Hz (X ) and area under the reactance curve (AX) were calculated. Two sets of analyses were conducted to address two separate questions: (1) whether mine fire exposure (a binary indicator; conceived after the mine fire vs in utero exposed) was associated with the respiratory Z-scores; (2) whether there was any dose-response relationship between fire-related PM exposure and respiratory outcomes among those exposed. Acceptable lung function measurements were obtained from 79 children; 25 unexposed and 54 exposed in utero. Median (interquartile range) for daily average and peak PM for the exposed children were 4.2 (2.6 - 14.2) and 88 (52-225) µg/m respectively. There were no detectable differences in Z-scores between unexposed and exposed children. There were no associations between respiratory Z-scores and in utero exposure to PM (daily average or peak). There was no detectable effect of in utero exposure to PM from a local coalmine fire on post-natal lung function 7-years later. However, statistical power was limited.