Increased impact of air pollution on lung function in preterm infants

Infants of mothers who are exposed to higher air pollution during pregnancy may have reduced lung function development. The presented study showed that significant negative associations during the second trimester of pregnancy were found between air pollution and postnatal lung function. Preterm infants showed significant higher susceptibility to air pollution exposure, leading to impaired postnatal lung function.

Infants born prematurely have impaired capacity to deal with oxidative stress shortly after birth. Particulate matter with a diameter >10 μm (PM₁₀) and NO₂ are known oxidative stressors to airways and lungs. Therefore, Ms Fabienne Decrue (University of Basel, Switzerland) and colleagues investigated whether preterm infants are more susceptible to pre- and postnatal exposure to air pollution in comparison to term infants, and if this is reflected in altered postnatal lung function [1,2].

Infants from the Basel-Bern infant lung development (BILD) cohort born between 1999–2017 were included. Individual air pollution (expressed in PM₁₀ and NO₂) exposure was calculated individually for each infant during the second trimester of pregnancy and postnatal. The primary outcome was postnatal lung function at 33 weeks postconceptional age, expressed as tidal breathing flow volume loops and exhaled surrogate markers of inflammation, and oxidative stress response (fractional exhaled nitrogen oxide, FeNO).

Within this study, 771 infants were included over a period of 18 years, of which one third were preterm infants (n=254). Preterm infants were divided over 2 groups: moderate-to-late preterm infants (32–37 weeks) and extreme preterm infants (<31 weeks). Significant associations of increases in PM₁₀ during pregnancy were found for minute ventilation, tidal volume, and FeNO (see Figure). Associations of air pollution and FeNO differed significantly between preterm and term infants (P=0.006).

Figure: Lung function as a result of PM₁₀ [1]



Ms Decrue was able to show that prenatal exposure to air pollution, especially during the second trimester of pregnancy, was associated with impaired infant lung function. Moreover, it was demonstrated for the first time that enhanced effects in preterm infants are suggestive of an amplified susceptibility indicating that air pollution measures should be taken to prevent populations at risk, even in low-to-moderate polluted areas such as Switzerland.

1. Decrue F, et al. Increased impact of air pollution on lung function in preterm vs. term infants: the BILD study. Abstract 2958. ERS 2021, 5–8 September.
2. Decrue F, et al. Am J Respir Crit Care Med. 2021 Sep 29.

 

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Posted on 9 November 20219 November 2021