Air pollution exposure while in womb can impact newborn’s stress responses: Study

A new study has established a link between prenatal exposure to air pollution and the negative impact on the cells — particularly related to stress response —of newborn babies.

Exposure to higher levels of nitrogen dioxide (NO2) and particulate matter (PM10) can bring down the dose of proteins that play a defensive role in stress resistance, inflammation and ageing, it noted.

The findings of the study were presented at the European Respiratory Society (ERS) International Congress on September 12, 2023, by Olga Gorlanova, a research physician at the University of Basel, Switzerland.

NO2 formed mainly from traffic emissions drives the levels of Beclin-1 protein, the research revealed. This protein is central to initiating autophagy — the “self-eating” of damaged cells in response to stress. The alterations in cell processes can be detected after a baby is born.

The researchers assessed the association of exposure to NO2 and PM10 with proteins linked to autophagy in 449 newborns from the Bern Basel Infant Lung Development (BILD) cohort study.

Vehicle emissions, tyre and brake wear and smoke are some of the sources of NO2 and PM10 pollutants. Exposure to NO2 was linked to a decrease in the activity of the proteins SIRT1 and IL-8 and an increase in levels of the Beclin-1 protein.

SIRT1 is a protein that plays a protective role in stress resistance, inflammation and ageing and IL-8 is a protein active in certain inflammatory cells.

There are visible alterations in these proteins of babies born to mothers exposed to air pollution during pregnancy, according to Gorlanova.

The study also showed that some newborns were more vulnerable to air pollution than others — even if the infants were born into households in areas with relatively low pollution levels.

The study adds to the growing body of evidence that autophagy-related mechanisms may be involved in how human cells react to air pollution.

“We already have enough evidence from this and other studies to be sending a message loud and clear to governments and policy-makers: Air pollution damages people’s health, and the effects can be seen from before birth,” said Marielle Pijnenburg, head of the ERS group on paediatrics.

Pijnenburg said:

We should all be re-doubling our efforts to reduce air pollution as quickly and as far as possible. This will not only improve the health of populations and reduce costs associated with treating diseases caused by air pollution, but will also help the environment at a time when the climate emergency is becoming more and more apparent as every day passes.

In 2019, 476,000 infants died in their first month of life from health effects associated with air pollution exposure. 

A 2021 study by Fabienne Decrue& et al published in the American Journal of Respiratory and Critical Care Medicine looked at the increased impact of air pollution on lung function in preterm (a baby born before 37 weeks of pregnancy) and term infants.

Preterm infants showed significantly higher susceptibility even to low to moderate prenatal air pollution exposure than term infants, leading to increased impairment of postnatal lung function.

Another study published in the journal Gut Microbes in 2022 established a link between inhaled pollutants — such as those from traffic, wildfires and industry — and changes in infant microbial health during the first six months.

In South Asia and sub-Saharan Africa, most stillbirths have been attributed to air pollution. Globally, in 2019, PM2.5 remained a great concern in the preterm birth burden, especially in western sub-Saharan Africa and South Asia. 

Between 1990 and 2019, the age-standardised burden of preterm birth due to ambient PM2.5 increased globally, according to a study published in Science of the Total Environment on May 1, 2023.