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Autism and traffic pollution: What is the link?

Kathleen Blanchard's picture
Traffic pollution and autism linked.

Researchers have been trying to understand the causes of autism. Results of a new finding published in the journal of the American Medical Association (JAMA), suggests one contributor might be exposure to traffic pollution before birth and in the first year of life.

The finding is important because it targets a potential prevention strategy for the disorder that affects primarily males and interferes with social and communications skills.

According to Autism Speaks, Rett syndrome, autistic disorder, childhood disintegrative disorder, pervasive developmental disorder (PDD-NOS) and Asperger's syndrome envelop the range of autism spectrum disorders (ASDs) that affect brain development and usually manifest in the first 2 to 3 years of life.

According to background information for the current study, there has been increased evidence that environmental factors play a role in autism development that still remains unclear.

Heather E. Volk, Ph.D., M.P.H., of the University of Southern California, and colleagues explored the link between autism and air quality from traffic pollution in a study that included 279 children with autism.

The investigation compared children with the disorder to 245 children as a control.

The study specifically focused on exposure to fine particulate matter from traffic sources, using addresses of mothers to estimate air quality during pregnancy and during a child’s first year of life.

Information used for the study was based on data from the Environmental Protection Agency's Air Quality System.

The authors found an increased risk of autism associated with exposure to traffic related pollution that they say warrants more study, “…to understand both individual pollutant contributions and the effects of pollutant mixtures on disease.”

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The results showed a three-fold increased risk of autism for children living in areas with the highest level of pollution from traffic, compared to children with the least exposure.

JAMA has published three articles on autism in the current issue.

"Urgent need" for more research

Geraldine Dawson, Ph.D., of the University of North Carolina at Chapel Hill, wrote in a commentary to the study:

"These articles point to an urgent need for more research on prenatal and early postnatal brain development in autism, with a focus on how genes and environmental risk factors combine to increase risk for ASD.

Despite a substantial increase in autism research publications and funding during the past decade, we have not yet fully described the causes of ASD or developed effective medical treatments for it.

Dawson calls for more research and points out the incidence of ASD has increased 78% in the past 6 years. Understanding how autism develops is important for prevention. Cost of the disease has more than tripled, she notes.

The authors concluded exposure to air pollution is common and could have “lasting neurological effects” that should be further explored. It’s possible that exposure to traffic pollution sets off a series of events that activates a biological pathway leading to autism. More research could uncover the how exposure to fine particulate matter and nitrogen dioxide from traffic might be a risk factor for autism.

Arch Gen Psychiatry
November 26, 2012.

"Autism Speaks"

Image credit: Morguefile