New research has found a link between exposure to air pollution during pregnancy and an increased risk of the offspring developing asthma as an adult.
The study looked at how a mother being exposed to air pollution – before and during pregnancy, and while breast feeding – can increase the risk of asthma in her children, even if those children are never directly exposed to the pollution themselves.
Researchers, from the School of Life Sciences at the University of Technology Sydney, Australia exposed a group of pregnant mice to particulate matter. Their offspring, along with the offspring of a control group, were divided into two groups, those with and those without asthma.
Of the asthma group, it was found that the mice whose mothers had been exposed to air pollution suffered more from airway hyperreactivity, in which the lungs are overly sensitive and react strongly to triggers such as allergens, exacerbating their asthma and making their symptoms worse.
To understand why this was happening, the scientists looked at how genes in the lungs were turned on or off in response to allergens. They found that in the offspring of pollution-exposed mothers, the usual immune and lung responses to allergens were weaker and very different from normal. This means the way their lungs responded had changed significantly—even though these offspring were never directly exposed to pollution.
They also looked at epigenetics – changes in how genes work, without changing the genes themselves. In this case, they focused on DNA methylation, a natural process that helps regulate gene activity. In the offspring of mothers exposed to pollution, these DNA changes were less frequent and weaker, especially in areas that usually help control genes.
The study shows that when mothers are exposed to air pollution, it can change how their children’s lungs develop and respond to allergens – likely through changes in gene regulation, not in the genes themselves. This suggests that air pollution can have lasting effects across generations and highlights the need for better air quality and new treatments that look at these long-term epigenetic changes.
Razia Zakarya, a researcher at the Epigenetics of Chronic Disease Group, Woolcock Institute of Medical Research said: ‘This suggests an epigenetic ‘memory effect’ of prenatal air pollution exposure that persists into adulthood, affecting the way genes related to lung function and immune response are regulated.’
Photo: Cnordic Nordic
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