Fine particulate air pollution linked to risk of childhood autism
May 21, 2015
University of Pittsburgh Schools of the Health Sciences
Exposure to fine particulate air pollution during pregnancy through the first two years of
the child’s life may be associated with an increased risk of a child developing autism
spectrum disorder, a condition that affects one in 68 children, according to an investigation
of children in southwestern Pennsylvania.
FULL STORY
Fine particulate air pollution refers to particles found in
the air that are less than 2.5 micrometers in diameter,
or 1/30th the average width of a human hair. It can be
found in dust, dirt, soot and smoke.
Credit: © Iliana Mihaleva / Fotolia
Exposure to fine particulate air pollution during pregnancy through the first two years of a
child’s life may be associated with an increased risk of the child developing autism spectrum
disorder (ASD), a condition that affects one in 68 children, according to a University of
Pittsburgh Graduate School of Public Health investigation of children in southwestern
Pennsylvania.
The research is funded by The Heinz Endowments and published in the July edition of Environmental
Research.
“Autism spectrum disorders are lifelong conditions for which there is no cure and limited treatment
options, so there is an urgent need to identify any risk factors that we could mitigate, such as pollution,”
said lead author Evelyn Talbott, Dr.P.H., professor of epidemiology at Pitt Public Health. “Our findings
reflect an association, but do not prove causality. Further investigation is needed to determine possible
biological mechanisms for such an association.”
Dr. Talbott and her colleagues performed a populationbased, casecontrol study of families with and
without ASD living in six southwestern Pennsylvania counties. They obtained detailed information about
where the mothers lived before, during and after pregnancy and, using a model developed by Pitt Public
Health assistant professor and study coauthor Jane Clougherty, Sc.D., were able to estimate individual
exposure to a type of air pollution called PM2.5.
This type of pollution refers to particles found in the air that are less than 2.5 micrometers in diameter, or
1/30th the average width of a human hair. PM2.5 includes dust, dirt, soot and smoke. Because of its
small size, PM2.5 can reach deeply into the lungs and get into the blood stream. Southwestern
Pennsylvania has consistently ranked among the nation’s worst regions for PM2.5 levels, according to
data collected by the American Lung Association.
“There is increasing and compelling evidence that points to associations between Pittsburgh’s poor air
quality and health problems, especially those affecting our children and including issues such as autism
spectrum disorder and asthma,” said Grant Oliphant, president of The Heinz Endowments. “While we
recognize that further study is needed, we must remain vigilant about the need to improve our air quality
and to protect the vulnerable. Our community deserves a healthy environment and clean air.”
Autism spectrum disorders are a range of conditions characterized by social deficits and communication
difficulties that typically become apparent early in childhood. Reported cases of ASD have risen nearly
eightfold in the last two decades. While previous studies have shown the increase to be partially due to
changes in diagnostic practices and greater public awareness of autism, this does not fully explain the
increased prevalence. Both genetic and environmental factors are believed to be responsible.
Dr. Talbott and her team interviewed the families of 211 children with ASD and 219 children without ASD
born between 2005 and 2009. The families lived in Allegheny, Armstrong, Beaver, Butler, Washington
and Westmoreland counties. Estimated average exposure to PM2.5 before, during and after pregnancy
was compared between children with and without ASD.
Based on the child’s exposure to concentrations of PM2.5 during the mother’s pregnancy and the first
two years of life, the Pitt Public Health team found that children who fell into higher exposure groups
were at an approximate 1.5fold greater risk of ASD after accounting for other factors associated with the
child’s risk for ASD such as the mother’s age, education and smoking during pregnancy. This risk
estimate is in agreement with several other recent investigations of PM2.5 and autism.
A previous Pitt Public Health analysis of the study population revealed an association between ASD and
increased levels of air toxics, including chromium and styrene. Studies by other institutions using
different populations also have associated pollutants with ASD.
“Air pollution levels have been declining since the 1990s; however, we know that pockets of increased
levels of air pollution remain throughout our region and other areas,” said Dr. Talbott. “Our study builds
on previous work in other regions showing that pollution exposures may be involved in ASD. Going
forward, I would like to see studies that explore the biological mechanisms that may underlie this
association.”
The above story is based on materials provided by University of Pittsburgh Schools of the Health
Sciences. Note: Materials may be edited for content and length.
Journal Reference:
1. Evelyn O. Talbott, Vincent C. Arena, Judith R. Rager, Jane E. Clougherty, Drew R. Michanowicz,
Ravi K. Sharma, Shaina L. Stacy. Fine particulate matter and the risk of autism spectrum
disorder. Environmental Research, 2015; 140: 414 DOI: 10.1016/j.envres.2015.04.021
