Researchers demonstrate that polluted air is associated with autism
Children’s exposure to air pollution is a major concern because their immune system and lungs are not fully developed. Overall evidence for the effects of air pollution has been growing and added to that evidence is autism as researchers find that air pollution whether regional or traffic related sources is associated to autism.
Researchers from the University of Southern California (USC) and Children’s Hospital Los Angeles, examined the relationship between traffic-related air pollution, air quality, and autism.
This population-based control study is the first to look at the amount of near-roadway traffic pollution individuals were exposed to and combine that with measures of regional air quality. The study includes data obtained from children with autism and control children with typical development who were enrolled in the Childhood Autism Risks from Genetics and the Environment study in California, which was also led by principal investigator Dr. Heather Volk, PhD, Assistant Professor of Preventive Medicine in the Division of Environmental Health, and holds a joint appointment with the Department of Pediatrics and the Zilkha Neurogenetic Institute. The study builds on previous research by Volk and colleagues that examined how close subjects lived to a freeway said Volk.
In the 2012 study, Dr. Volk and associates examined data on 279 autism cases and 245 control subjects enrolled in the California-based Childhood Autism Risks from Genetics and the Environment (CHARGE) study. Mothers’ addresses from birth certificates and addresses reported from a residential history were used to estimate exposure during each trimester of pregnancy and the first year of life. The researchers used air pollution levels derived from the Environmental Protection Agency’s Air Quality System to determine exposure to NO2, PM2.5, and PM10. They also applied dispersion models to estimate the amount of traffic the mothers and children were exposed to.
Researchers had taken into account the distance people resided from roadways, meteorology such as direction the wind was blowing, how busy the road was, and other factors to study traffic-related pollution said Volk.
The research revealed that that exposure to traffic-related air pollution during pregnancy and the first year of life is associated with a more than two-fold risk of autism. Also revealed was that exposure to regional pollution consisting of nitrogen dioxide (NO2) and small particles(less than 2.5 and 10 microns in diameter) is also associated to autism even if the mother did not reside near a busy roadway.
Particularly interesting was the effect of mothers’ and children’s exposure to particles, both PM10 and PM2.5. PM10 includes both coarse and fine particles, while PM2.5 includes only the smaller (fine) particles, which are most likely to have deleterious effects on the human body.
The researchers had written in their conclusion “Exposure to traffic-related air pollution, nitrogen dioxide, PM2.5, and PM10 during pregnancy and during the first year of life was associated with autism. Further epidemiological and toxicological examinations of likely biological pathways will help determine whether these associations are causal.”
Dr. Volk stated “From studies conducted in the lab, we know that we can breathe in tiny particles and they can produce inflammation.” “Particles have varied composition, and there are many chemicals that can bind to them. The components of these particles could be hazardous to the brain.”
Dr. Geraldine Dawson, PhD, child clinical psychologist specializing in autism, Research Professor of Psychiatry at the University of North Carolina at Chapel Hill and Chief Science Officer for Autism Speaks, the world’s largest autism science and advocacy organization. She also holds the positions of Adjunct Professor of Psychiatry at Columbia University and Professor Emeritus of Psychology at University of Washington. She is a Fellow of the American Psychological Society, American Psychological Association, and the Society of Clinical Child and Adolescent Psychology in part had wrote in an accompanying editorial he latest study “confirms earlier studies that exposure to environmental toxins, especially during the prenatal period, can increase the risk of autism.”
“There is an urgent need for more research on environmental factors that can influence prenatal brain development and potentially increase risk for autism,” stated Dawson.
Dr. Volk colleagues are now at work on a study of how genes related to autism may be affected by environmental exposures to try to identify if there are factors that make people are genetically more vulnerable to particular pollutants.
The study is published in the Archives of General Psychiatry, a sister publication of the Journal of the American Medical Association.
In an article that appeared in Pediatrics, authored by Dr. Joe Schwartz, PhD, Departments of Environmental Health and Epidemiology, Harvard School of Public Health, and Channing Laboratory, Brigham and Women’s Hospital, Department of Medicine, Harvard Medical School, Boston, Massachusetts had wrote in his abstract children have been shown to be at particular risk for other effects of air pollution.
In his paper he had wrote in part the following conclusion “Air pollution is not the leading cause of death or morbidity in children in the developed world. However, there is increasingly strong evidence that air pollution is associated with nontrivial increases in the risk of death and chronic disease in children, worse pregnancy outcomes, and exacerbation of illnesses. It is less clear which pollutants are most responsible, but particles and ozone have the strongest associations. For the incidence of asthma, traffic pollution, particularly from trucks, seems to be the key player.”
His article titled Air Pollution and Children’s Health appears in the journal Pediatrics, Vol. 113, April 1, 2004.
According to Dr. Robert J. Laumbach, MD, MPH, University of Medicine and Dentistry of New Jersey–Robert Wood Johnson Medical School, Piscataway, New Jersey, writes “ Almost 160 million persons live in areas of the United States that exceed federal health-based air pollution standards. The two air pollutants that most commonly exceed standards are ozone and particulate matter.” “Persons who are aware of local air pollution levels, reported daily by the U.S. Environmental Protection Agency as the Air Quality Index, can take action to reduce exposure. These actions include simple measures to limit exertion and time spent outdoors when air pollution levels are highest, and to reduce the infiltration of outdoor air pollutants into indoor spaces.”
Information on outdoor air pollution can be found online at American Family Physician.