Air Pollution Exposure May Increase Risk of Autism, Schizophrenia: Study

The findings of new research suggest that exposure to air pollution for children may cause brain changes, which are linked to the development of autism, schizophrenia and other neurological disorders. 

In a study published in the medical journal Environmental Health Perspectives on June 5, researchers indicate that a link was found between pollution exposure and permanent inflammation and high levels of a neurotransmitter found in humans who have autism and schizophrenia.

While the results do not conclusively link pollution to the development of the two illnesses, it does offer researchers environmental cues to consider.

During the study, mice younger than two weeks were exposed to concentrated ambient ultra-fine particles of pollution similar to what is found in the air during rush hour in cities like Los Angles, Boston, Atlanta and New York City for various amounts of time.

Researchers used the Harvard University Concentrated Ambient Particle System (CAPS). Three groups of mice were then examined 24 hours, 40 days and 270 days after the exposure stopped. Researchers noted an increased size in specific regions of the brain, the ventricles, chambers on either side of the brain which contain cerebrospinal fluid.

Enlarged ventricles, ventriculomegaly, are often connected to varying degrees of neurodevelopment impairment. Mostly male mice experienced this change; a change often seen with autism and schizophrenia. This is especially important considering men are more likely to be diagnosed with autism and schizophrenia than women, researchers say.

Researchers also found mice performed poorly on short-term memory activities, had a decreased learning ability and displayed increased levels of impulsivity.

The exposure to CAPS was found to affect the central nervous system (CNS). The effects were long-lasting and still remained evident 10 months after exposure was discontinued.

Particulates are small bits of air pollution. Currently the U.S. Environmental Protection Agency (EPA) regulates large particles of air pollution, which are considered more harmful to humans. However, large particles are filtered by the nose and lungs, keeping them from entering the bloodstream. Smaller particles are not filtered this way, allowing them to travel to the lungs and bloodstream, making them potentially more dangerous.

“For me it’s about primary prevention,” said Deborah Cory-Slechta, lead researcher and professor of Environmental Medicine at the University of Rochester Medical Center. “Maybe we should be thinking about regulating differently. Maybe we should focus on monitoring of the ultra-fine particles that are there.”

Studies have found pollution to cause widespread side effects concerning the lungs and heart, but not many have found how pollution can affect the brain. A study published last year found children exposed to heavy-traffic related pollution during first year of life are three times more likely to develop autism.

The new study also highlighted while the results do not reveal cause and effect, they could lead to increased regulations on smaller particulate types of pollutants.

One particular risk factor may not be the sole cause of conditions like autism and schizophrenia. It may be an interaction of all the risk factors in life which come together to cause them.