Objective: To evaluate whether vascular health in young children was associated with exposure to a 6-week episode of coal mine fire smoke or environmental tobacco smoke (ETS) in a retrospective cohort study.

Methods: Three years after a coal mine fire in Victoria, Australia, we investigated the vascular health of children either in utero (n = 75) or aged < 2 years (postnatal exposure, n = 96) at the time of the fire. The outcomes were the carotid intima-media thickness (IMT) and pulse wave velocity (PWV). The mean and peak daily particulate matter < 2.5 µm in diameter (PM_2.5) exposures were estimated based on their daily locations throughout the fire period. Multivariable linear regression models were used to test for associations between the fire-related PM_2.5 and outcomes adjusted for relevant covariates including ETS.

Results: In the postnatal-exposure group, each 10 µg/m³ increase in mean PM_2.5 level was independently positively associated with PWV (β = 0.116, p = 0.028). When these two groups were combined, there was an association between mean PM_2.5 and increased PWV in those children who had ETS exposure (β = 0.148, p = 0.033) or whose mothers smoked (β = 0.151, p = 0.011), but not in those not exposed to ETS or maternal smoking.

Conclusions: Three years after a coal mine fire, infants aged up to 2 years at the time of exposure have increases in vascular stiffness. Although no adverse effects were observed in the in uterus exposure group, further follow-up study is needed to elucidate the long-term effects of coal mine fire smoke exposure.