New Study Links Pollution and Autism

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air pollution linked to autism

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According to a new study by UCLA researchers, there’s a correlation with babies exposed to air pollution in the womb and autism—a spectrum of disorders ranging from a profound inability to communicate and mental disability to milder symptoms seen in Asperger’s syndrome that affects one in every 88 children born in the United States.

The researchers looked at children born between 1995 to 2006 in Los Angeles (specifically, 7,603 children with autism and 75,635 children without autism) to compare levels of air pollution. They used birth certificates to compare birth year, sex, and gestational age at birth; government air monitoring stations to come up with estimations of exposure to carbon monoxide, nitrogen dioxide, nitric oxide, ozone and particulate matter; and adjusted for variables, including: maternal age, birthplace, race, and education

The study, published March 1 in Environmental Health Perspectives—a peer-reviewed journal published by the National Institute of Environmental Health Sciences—found that babies with higher exposure to toxins were 8 to 10 percent more at risk of autism than those who were not. Of the toxins, ozone and fine particulates had the strongest correlation with autism. What’s more, the study found that the highest rates of autism were among children of older, more educated, white parents.

“These findings are of concern, since traffic-related air pollution is ubiquitous,” said Dr. Beate Ritz, chair of UCLA’s Department of Epidemiology and the study’s senior author, to The Huffington Post. “We can’t tell them to not breathe or not go outside or not go to work,” she said. She did recommend avoiding sitting in traffic, when pollutant exposure is worst.

This study is very telling, as there is limited research on autism and exposure to chemicals. While previous studies from 2006 and 2010 have found a correlation with autism and pollutants, this study is the largest of its kind. According to The Huffington Post:

study in 2010 was the first to look at autism and toxins specifically from auto exhaust. The study, based in California, reported that children born to mothers living within 9/10 mile of a freeway during pregnancy were more likely to be diagnosed with autism than children whose mothers lived more than 1/4 mile from a freeway. However, the sample size — 304 autism cases and 259 controls — was much smaller than the just-published UCLA study.

The UCLA study is first to suggest a link between autism and ozone. The ozone level in LA is the highest in the nation and violates federal health standards an average of 137 days a year.

Research has found various environmental factors that appear to affect brain development, including pesticides, nutrition, flame retardants and parent’s occupational exposures. Other factors that have been tied to autism specifically include drugs used decades ago to treat morning sickness, bipolar disorder and ulcers.

“Ideally, future autism and air pollu­tion studies should use neighborhood­level monitoring or modeling of air toxins such as polycyclic aromatic hydrocarbons and pos­sibly speciated PM2.5 to determine whether these results are reproducible with improved air pollution assessment,” write the studies of the author.

  • Susmita Baral

    Susmita is a writer and editor in the Greater New York City area. In her spare time, Susmita enjoys cooking, traveling, dappling in photography, art history and interior design, and moonlighting as a therapist for her loved ones.

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