Living Near Freeways May Increase Risk of Autism


Link to autism and environmental factors still needs more research.

freewayA current study has been released reporting a possible link between autism and living near freeways. Published by a team of researchers from Children’s Hospital Los Angeles, the Keck School of Medicine of the University of Southern California (USC) and the UC Davis MIND Institute states that infants born to mothers who live close to freeways have twice the risk of autism.

The study did not find a link between autism and proximity to a major road, as opposed to a freeway. “These findings may be due to the type and quantity of chemicals dispersed on freeways compared with major roads,” said Heather Volk, lead author of the paper and a researcher at the Saban Research Institute of Children’s Hospital Los Angeles.

“This study isn’t saying exposure to air pollution or exposure to traffic causes autism,” Volk stated. “We know there are some chemicals in air pollution coming from diesel exhaust that might be a good forerunner to look at…we really don’t know what it is about air pollution that is associated with autism.”

Researchers studied 304 children with autism and 259 children who were neurotypical between the ages of 24 and 60 months living in and around Los Angeles, San Francisco and Sacramento.

Data was recorded on where each child’s mother lived during pregnancy and at the time of birth, and the proximity of the homes to a major road or freeway. They also conducted in-person interviews of each family and preformed developmental assessments on the children.

Children living about 1,000 feet from a freeway at birth (10% of the sample) had a two-fold increase in autism risk. The link held up even after researchers controlled for other factors that may influence development, such as ethnicity, parental education, maternal age and exposure to tobacco smoke.

“Research like this suggests environmental factors need more attention,” said Clara Lajonchere, vice president of clinical programs for the advocacy group Autism Speaks. Lajonchere was not involved in the study.

It should be noted that this study requires more research and replication before results can be conclusive. Future studies should also be conducted to identify air pollutants and their potential risk. Autism is a developmental disorder which experts believe is caused by genetic factors. However, with spikes in recent diagnosis, more and more experts are looking to environmental factors or a combination of environmental and genetic factors as another possible cause.

“We expect to find many, perhaps dozens, of environmental factors over the next few years, with each of them probably contributing to a fraction of autism cases. It is highly likely that most of them operate in conjunction with other exposures and/or with genes,” said Irva Hertz-Picciotto, Ph.D., chief of the division of environmental and occupational health in the Department of Public Health Sciences at UC Davis.

As scientific research continues on the cause or causes of autism, parents whose children are diagnosed can often times feel guilty or blame themselves. It is important to remember that no matter what research is uncovered, the most productive action for parents is to focus on treatment options and advocacy of services for their child.

Learn More About Autism

Treatment Options for Autism

Establishing Services For Your Child

Living near freeway linked to increased risk of autism.” The Medical News, December 16, 2010.
“Proximity to freeways increases autism risk, study finds.”Los Angeles Times, December 16, 2010.