Long-term exposure to air pollutants is known to affect physical well-being, increasing the risk of respiratory illnesses, cardiovascular diseases, and cancers. A recent study revealed that early-life exposure to air pollution has lasting effects on the brain.
According to the research led by the Barcelona Institute for Global Health (ISGlobal), exposure to fine particles (PM2.5) and nitrogen oxides (NOx) during pregnancy and childhood can lead to significant changes in the microstructure of the brain’s white matter. Alarmingly, these alterations can persist into adolescence, raising concerns about the long-term impact of air pollution on brain development.
Earlier studies have explored the impact of air pollutants on the brain’s white matter, but most were limited to a single time point and did not track participants throughout childhood.
The latest study published in Environmental Research involved 4,000 participants in Rotterdam, the Netherlands who were part of the Generation R Study and were followed up since birth. Based on the participants’ location, the team estimated the amount of exposure to 14 different air pollutants during pregnancy and childhood.
To examine changes in white matter microstructure, researchers conducted brain scans on 1,314 children, once around the age of 10 and again around 14.
“Following participants throughout childhood and including two neuroimaging assessments for each child would shed new light on whether the effects of air pollution on white matter persist, attenuate, or worsen,” said ISGlobal researcher Mònica Guxens in a news release.
The results revealed that higher exposure to PM2.5 during pregnancy, as well as elevated levels of PM2.5, PM10, PM2.5-10, and NOx during childhood, led to a reduction in fractional anisotropy, a measure of how water molecules diffuse within the brain. In more mature brains, water tends to flow more in one direction, resulting in higher values for this marker. This association persisted into adolescence, indicating a long-term impact of air pollution on brain development.
“Every increase in exposure level to air pollution corresponded to more than a 5-month delay in the development of fractional anisotropy,” the researchers wrote.
“We think that the lower fractional anisotropy is likely the result of changes in myelin, the protective sheath that forms around the nerves, rather than in the structure or packaging of the nerve fibers,” said first author of the study, Michelle Kusters.