Autism Risk Increases With Exposure To Air Pollution

Autism Risk Increases With Exposure To Air Pollution27 Nov 2012-nbsp;-nbsp;-nbsp;

Exposure to traffic-related air pollution, nitrogen dioxide, and particulate matter during pregnancy and during a child's first year of life may be linked to a higher risk of autism.


The finding came from University of Southern California (USC) and Children's Hospital Los Angeles researchers and was published Online First by Archives of General Psychiatry, a JAMA Network publication.


Autism is a complex developmental disability and it has both genetic and environmental elements that play a part in its origins. Autism spectrum disorders are often distinguished by problems with:

social interaction
communication
repetitive behaviors



Although there is new research indicating that the environment plays a particular part in autism, little is known about:

what exposures are linked
their procedure of action
the stages in development in which they act
the development of successful preventive actions



The team, led by Heather E. Volk, Ph.D., M.P.H., set out to observe the association between traffic-related air pollution, air quality, and autism. In order to do so, they analyzed data of 279 kids with autism and a control group of 245 kids developing normally who participated in the Childhood Autism Risks from Genetics and the Environment study conducted in California.


The authors explained:

"Exposures to traffic-related air pollution, PM [particulate matter] and nitrogen dioxide were associated with an increased risk of autism. These effects were observed using measures of air pollution with variation on both local and regional levels, suggesting the need for further study to understand both individual pollutant contributions and the effects of pollutant mixtures on disease."

The addresses of the moms were used so that the scientists could approximate exposure for each pregnancy trimester and for a child's first year after being born. Using a model, traffic-related air pollution was measured, and using the Environmental Protection Agency's Air Quality System data, regional air pollution was estimated.

Results showed that kids whose homes had the greatest levels of modeled traffic-related air pollution had a 3 times higher chance of autism, compared to those living in places with the lowest exposure.

The researchers also discovered that the higher levels of exposure to particulate matter less than 2.5 and 10µm in diameter and nitrogen dioxide based on the EPA's regional air quality monitoring program were linked to an elevated risk of autism.


The team concluded:

"Research on the effects of exposure to pollutants and their interaction with susceptibility factors may lead to the identification of the biologic pathways that are activated in autism and to improved prevention and therapeutic strategies. Although additional research to replicate these findings is needed, the public health implications of these findings are large because air pollution exposure is common and may have lasting neurological effects."




Editorial: Significant Increase in Autism Prevalence Parallels Increase in Research


Geraldine Dawson, Ph.D., of the University of North Carolina at Chapel Hill, wrote in an editorial: "This issue of the journal features three articles on autism. A decade ago, the journal published about the same number of autism articles per year. This reflects a broad expansion in the number and diversity of research publications on autism spectrum disorder (ASD)."


"The upsurge of research parallels a dramatic increase in autism prevalence during the same period. In the past six years alone, the prevalence of ASD has increased 78 percent and the estimated annual cost of autism has more than tripled," Dawson added.


"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. More research is needed to develop strategies for preventing or reducing the disabling symptoms associated with this highly prevalent and costly neurodevelopmental disorder," Dawson concluded.

Written by Sarah Glynn

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