THE ESSENTIAL
- Exposure to air pollutants during critical periods of child development may increase the risk of autism.
- The new study shows that common pollutants, such as fine particles and nitrogen oxide, can trigger complex biological cascades affecting the brain.
- For researchers, additional studies are needed on the phenomenon.
The global prevalence of autism spectrum disorder (ASD) is now estimated at between 1 and 1.5% of the population. Air pollution could play a role in the development of this neurological problem, according to a study published November 12, 2024 in the journal Brain Medicine.
Researchers have, in fact, noticed that exposure at a fetal stage or in early childhood to common air pollutants – such as fine particles and nitrogen oxide – triggers complex biological cascades affecting brain development. Which would lead to an increased risk of ASD.
Autism and air pollution: increased vulnerability early in life
By reviewing studies carried out in recent years on the impact of atmospheric pollution on brain development, researchers have shown that pollutants such as fine particles and nitrogen oxide (NO) are risk factors for autism.
“The timing of exposure appears crucial, with vulnerability increased during prenatal development and early childhood, when critical neurodevelopmental processes occur”explains Professor Haitham Amal of the Hebrew University of Jerusalem, lead author of the study, in a press release.
“Research suggests that people with a genetic predisposition to ASD may be more vulnerable to the harmful effects of exposure to air pollution”notes Professor Amal. “This interaction between genetic and environmental factors opens new perspectives for understanding the complex etiology of ASD”he adds.
Fine particles: several effects on the body identified
The team also identified several pathways through which air pollution could influence the development of autism spectrum disorders in young children. She noticed that pollutants are linked to neuronal inflammation and oxidative stress. These elements also seem to promote the disruption of neurotransmitter systems, epigenetic modifications, interference with the endocrine system as well as dysregulation of metabolic pathways. Exposure to nitric oxide is also associated with an increase in nitrosative stress, a phenomenon linked to several health problems.
“It is particularly worrying that fine particles, including PM2.5 and products containing NO, can cross the placenta and affect fetal brain development. This finding raises important questions about protective measures to adopt by pregnant women living in highly polluted areas”underline the authors.
For them, it is essential to conduct in-depth studies on the combined effects of several pollutants, particularly during fetal life or childhood, to develop effective prevention strategies.
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