Cited by 355Air Quality and Health ImpactsAutism Spectrum Disorder ResearchEnvironmental Justice and Health Disparities

Ambient Air Pollution and Autism in Los Angeles County, California

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Becerra, Tracy Ann, Wilhelm, Michelle, Olsen, Jørn, Cockburn, Myles, Ritz, Beate·2013·Environmental Health Perspectives

Abstract

Background: The prevalence of autistic disorder (AD), a serious developmental condition, has risen dramatically over the past two decades, but high-quality population-based research addressing etiology is limited. Objectives: We studied the influence of exposures to traffic-related air pollution during pregnancy on the development of autism using data from air monitoring stations and a land use regression (LUR) model to estimate exposures. Methods: Children of mothers who gave birth in Los Angeles, California, who were diagnosed with a primary AD diagnosis at 3–5 years of age during 1998–2009 were identified through the California Department of Developmental Services and linked to 1995–2006 California birth certificates. For 7,603 children with autism and 10 controls per case matched by sex, birth year, and minimum gestational age, birth addresses were mapped and linked to the nearest air monitoring station and a LUR model. We used conditional logistic regression, adjusting for maternal and perinatal characteristics including indicators of SES. Results: Per interquartile range (IQR) increase, we estimated a 12–15% relative increase in odds of autism for ozone [odds ratio (OR) = 1.12, 95% CI: 1.06, 1.19; per 11.54-ppb increase] and particulate matter ≤ 2.5 µm (OR = 1.15; 95% CI: 1.06, 1.24; per 4.68-μg/m3 increase) when mutually adjusting for both pollutants. Furthermore, we estimated 3–9% relative increases in odds per IQR increase for LUR-based nitric oxide and nitrogen dioxide exposure estimates. LUR-based associations were strongest for children of mothers with less than a high school education. Conclusion: Measured and estimated exposures from ambient pollutant monitors and LUR model suggest associations between autism and prenatal air pollution exposure, mostly related to traffic sources.

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  • The size of ORs was not consistent across studies despite standardized comparison, for example ORs were around 1.5 per 10 ppb increase in NO2 for the California CHARGE study but only 1.04 for the California Department of Developmental Services study.

    “The size of the ORs was not consistent across studies, despite the standardized comparison of air pollutant concentrations that we calculated, for example, ORs were around 1.5 per 10 ppb increase in NO2 for the California CHARGE study (Fig. 3, red),72 but only 1.04 for the California Department of Developmental Services study (Fig. 3, green).73”
  • Confounding by family social characteristics was expected, but its degree was not strong and acted in opposite directions across studies, attenuating ORs in some studies and producing elevated ORs in others.

    “Although confounding by such family social characteristics was expected, the degree of this confounding was not strong and acted in opposite directions across studies, attenuating ORs in some studies71,72 and producing elevated ORs in other studies.73,74”
  • Leave-one-out analysis identified one study [39] as contributing to the majority of heterogeneity in the PM2.5 meta-analysis, and no particular methodological features driving heterogeneity could be identified.

    “Again using a leave-one-out analysis, we identified one study in particular [39] that was contributing to the majority of the heterogeneity and we could not identify particular methodological features driving the heterogeneity so we classified it as unexplained.”
  • Sensitivity analysis for PM2.5 found an added study would need an effect estimate of OR = 1.02 to enlarge the confidence interval to overlap 1, and OR = 0.14 to shift the overall effect estimate to OR<1.

    “Sensitivity analyses here (assuming the added hypothetical study would have a standard error of 0.04, equal to the smallest in our group of studies [39]) found that an added study would need an effect estimate of OR = 1.02 to enlarge the confidence interval to overlap 1, and an OR = 0.14 to shift the overall effect estimate to OR<1.”

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Research works printed but not linked: 2

  1. American Psychiatric Association 2000 Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision Washington, DC American Psychiatric Association
  2. Institute of Medicine 1999 Toward Environmental Justice: Research, Education, and Health Policy Needs. Available: http://www.iom.edu/Reports/1999/Toward-Environmental-Justice-Research-Education-and-Health-Policy-Needs.aspx [accessed 9 December 2012] 23035313

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Authors
Becerra, T. A., Wilhelm, M., Olsen, J., Cockburn, M., & Ritz, B.
Affiliations
  • University of California, Los Angeles (US)
  • University of Southern California (US)
Corresponding author
Ritz, Beate
Venue
Environmental Health Perspectives
Published
2012-12-18
Volume
121
Issue
3
Pages
380-386
ISSN
  • 0091-6765 (ISSN-L)
  • 1552-9924
OpenAlex
W2070534968
Cited by
355
References
48
Citations by year
2026: 17 · 2025: 26 · 2024: 24 · 2023: 16 · 2022: 28 · 2021: 24 · 2020: 37 · 2019: 36 · 2018: 32 · 2017: 25 · 2016: 30 · 2015: 28 · 2014: 26 · 2013: 6
FWCI
13.29
Type
journal article
Language
en
Open access
Locations
  • Environmental Health Perspectives (publishedVersion, public-domain)
  • Europe PMC (PubMed Central) (publishedVersion, public-domain)
  • PubMed Central (publishedVersion, public-domain)
  • PubMed (publishedVersion)
Funders
  • National Institute of Environmental Health Sciences (R01ES010960)
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development (R24HD041022)
Topics
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Air Quality and Health Impacts
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Autism Spectrum Disorder Research
  • Social Sciences › Sociology and Political Science › Environmental Justice and Health Disparities
Keywords
autism spectrum disorder, prenatal air pollution exposure, traffic-related air pollution, ozone, particulate matter, nitrogen dioxide, nitric oxide, maternal education, developmental neurotoxicity, Los Angeles County
MeSH terms
Air Pollution, Autistic Disorder, Child, Preschool, Environmental Exposure, Female, Humans, Male, Los Angeles, Case-Control Studies

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