Air pollution emerges as critical environmental risk factor for autism, emerging topic review finds

Boston, Massachusetts, 12 November 2024 – Environmental exposure to air pollutants during critical developmental periods may significantly impact autism risk, according to a groundbreaking Emerging Topic review published 12 November 2024, in Brain Medicine. The study reveals how common air pollutants, including fine particulate matter and nitrogen oxides, can trigger complex biological cascades affecting brain development.

"Different kinds of neurological disorders, including autism spectrum disorder, can be associated with this environmental factor," explains Professor Haitham Amal from the Hebrew University of Jerusalem, the study's senior author. "The timing of exposure appears crucial, with heightened vulnerability during prenatal development and early childhood when critical neurodevelopmental processes occur."

The review identifies several key pathways through which air pollutants may influence ASD development:

• Nitrosative stress orchestrated by nitric oxide (NO)

• Neuroinflammation and oxidative stress

• Disruption of neurotransmitter systems

• Epigenetic modifications

• Endocrine system interference

• Metabolic pathway dysregulation

Of particular concern is the finding that smaller particles, especially PM2.5 as well as NO products, can cross the placenta and affect fetal brain development. This revelation raises important questions about protective measures for pregnant women in highly polluted areas.

"The research suggests that individuals with genetic predisposition to ASD may be more vulnerable to the harmful effects of air pollution exposure," Professor Amal notes. "This interaction between genetic and environmental factors opens new avenues for understanding ASD's complex etiology."

“My lab has shown that NO plays a major role in ASD. However, this study emphasizes the critical role of this molecule and its derivatives on the brain” Prof. Amal comments. 

The review, first authored by PhD student Shashank Ojha, also highlights promising directions for biomarker development, potentially enabling early identification of at-risk individuals. These findings arrive at a crucial time, as global ASD prevalence reaches 1-1.5% of the population.

The implications extend beyond individual health to public policy. How might cities need to adapt their urban planning to protect vulnerable populations? What role could air quality monitoring play in prenatal care? These questions become increasingly urgent as urbanization continues worldwide.

The research team emphasizes the need for comprehensive studies examining the combined effects of multiple pollutants, particularly during specific developmental windows. Understanding these interactions could prove crucial for developing effective preventive strategies.

The Emerging Topic review, titled “Air Pollution: An Emerging Risk Factor for Autism Spectrum Disorder,” will be published in Brain Medicine on November 12, 2024. It will be freely available online at https://url.genomicpress.com/2p8wcjw3.

About Brain Medicine: Brain Medicine (ISSN: 2997-2639) is a peer-reviewed journal published by Genomic Press, New York. Brain Medicine is a new home for the cross-disciplinary pathway from innovation in fundamental neuroscience to translational initiatives in brain medicine. The journal’s scope includes the underlying science, causes, outcomes, treatments, and societal impact of brain disorders, across all clinical disciplines and their interface.