Epidemiologic studies have reported associations between prenatal and early postnatal air pollution exposure and autism spectrum disorder (ASD); however, findings differ by pollutant and developmental window.
We examined associations between early life exposure to particulate matter ≤2.5 µm in diameter (PM2.5) and ozone in association with ASD across multiple US regions.
Our study participants included 674 children with confirmed ASD and 855 population controls from the Study to Explore Early Development, a multi-site case–control study of children born from 2003 to 2006 in the United States. We used a satellite-based model to assign air pollutant exposure averages during several critical periods of neurodevelopment: 3 months before pregnancy; each trimester of pregnancy; the entire pregnancy; and the first year of life. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for study site, maternal age, maternal education, maternal race/ethnicity, maternal smoking, and month and year of birth.
The air pollution–ASD associations appeared to vary by exposure time period. Ozone exposure during the third trimester was associated with ASD, with an OR of 1.2 (95% CI: 1.1, 1.4) per 6.6 ppb increase in ozone. We additionally observed a positive association with PM2.5 exposure during the first year of life (OR = 1.3 [95% CI: 1.0, 1.6] per 1.6 µg/m3 increase in PM2.5).
Our study corroborates previous findings of a positive association between early life air pollution exposure and ASD, and identifies a potential critical window of exposure during the late prenatal and early postnatal periods.
From the aDepartment of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC
bDepartment of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY
cCalifornia Department of Public Health, Richmond, CA
dDepartment of Environmental Health Sciences, Joseph J. Zilber School of Public Health, University of Wisconsin-Milwaukee, Milwaukee, WI
eDepartment of Environmental Health, Boston, Harvard T.H. Chan School of Public Health, MA
fDivision of Research, Kaiser Permanente, Oakland, CA
gWendy Klag Center for Autism and Developmental Disabilities, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
hDepartment of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
iEnvironmental Sciences and Policy Division, Nicholas School of the Environment, Duke University, Durham, NC
jDepartment of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
kEnvironmental Public Health Division, United States Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, NC
lNational Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA.
Submitted October 18, 2018; accepted September 24, 2019.
Supported by the Centers for Disease Control and Prevention (cooperative agreements U10DD000180, U10DD000181, U10DD000182, U10DD000183, U10DD000184, and U10DD000498). Additional support was provided by the National Institutes of Health (T32ES007018 and T32HD049311).
The authors report no conflicts of interest.
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. The views expressed in this article are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency. Any mention of trade names, products, or services does not imply an endorsement by the U.S. Government or the U.S. Environmental Protection Agency (EPA). The EPA does not endorse any commercial products, services, or enterprises.
Supplemental digital content is available through direct URL citations in the HTML and PDF versions of this article (www.epidem.com).
All code used for the analyses described in this article can be available upon request. The outcome data are not available for replication due to the sensitive nature of the outcome. Air pollution exposure data are available upon request.
Correspondence: Laura A. McGuinn, Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1057, New York, NY 10029. E-mail: email@example.com.