title: Traffic-related air pollution, particulate matter, and autism.
abstract: BACKGROUND
  Autism is a heterogeneous disorder with genetic and environmental factors likely contributing to its origins. Examination of hazardous pollutants has suggested the importance of air toxics in the etiology of autism, yet little research has examined its association with local levels of air pollution using residence-specific exposure assignments.
  
  
  OBJECTIVE
  To examine the relationship between traffic-related air pollution, air quality, and autism.
  
  
  METHODS
  This population-based case-control 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. The mother's address from the birth certificate and addresses reported from a residential history questionnaire were used to estimate exposure for each trimester of pregnancy and first year of life. Traffic-related air pollution was assigned to each location using a line-source air-quality dispersion model. Regional air pollutant measures were based on the Environmental Protection Agency's Air Quality System data. Logistic regression models compared estimated and measured pollutant levels for children with autism and for control children with typical development.
  
  
  METHODS
  Case-control study from California.
  
  
  METHODS
  A total of 279 children with autism and a total of 245 control children with typical development.
  
  
  METHODS
  Crude and multivariable adjusted odds ratios (AORs) for autism.
  
  
  RESULTS
  Children with autism were more likely to live at residences that had the highest quartile of exposure to traffic-related air pollution, during gestation (AOR, 1.98 [95% CI, 1.20-3.31]) and during the first year of life (AOR, 3.10 [95% CI, 1.76-5.57]), compared with control children. Regional exposure measures of nitrogen dioxide and particulate matter less than 2.5 and 10 μm in diameter (PM2.5 and PM10) were also associated with autism during gestation (exposure to nitrogen dioxide: AOR, 1.81 [95% CI, 1.37-3.09]; exposure to PM2.5: AOR, 2.08 [95% CI, 1.93-2.25]; exposure to PM10: AOR, 2.17 [95% CI, 1.49-3.16) and during the first year of life (exposure to nitrogen dioxide: AOR, 2.06 [95% CI, 1.37-3.09]; exposure to PM2.5: AOR, 2.12 [95% CI, 1.45-3.10]; exposure to PM10: AOR, 2.14 [95% CI, 1.46-3.12]). All regional pollutant estimates were scaled to twice the standard deviation of the distribution for all pregnancy estimates.
  
  
  CONCLUSIONS
  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.
authors: Department of Preventive Medicine, Keck School of Medicine, Zilkha Neurogenetic Institute, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA 90089, USA. hvolk@usc.edu
authors: Heather E
authors: HE
authors: Volk
authors: Fred
authors: F
authors: Lurmann
authors: Bryan
authors: B
authors: Penfold
authors: Irva
authors: I
authors: Hertz-Picciotto
authors: Rob
authors: R
authors: McConnell
mesh_terms: D000397:Air Pollution / Q000009:adverse effects*; D001321:Autistic Disorder / Q000453:epidemiology / Q000209:etiology*; D002140:California / Q000453:epidemiology; D016022:Case-Control Studies; D002675:Child, Preschool; D004784:Environmental Monitoring; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009585:Nitrogen Dioxide / Q000009:adverse effects; D052638:Particulate Matter / Q000009:adverse effects*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D011795:Surveys and Questionnaires
chemical_list: D052638:Particulate Matter; D009585:Nitrogen Dioxide
references: Environ Sci Technol. 2007 Apr 1;41(7):2223-30
references: 17438767
references: Neurotoxicology. 2007 Sep;28(5):965-78
references: 17606297
references: Environ Health Perspect. 2005 Nov;113(11):1555-60
references: 16263511
references: Nat Rev Neurosci. 2002 Mar;3(3):216-27
references: 11994753
references: Pediatrics. 2009 Aug;124(2):e195-202
references: 19620194
references: Epidemiology. 2010 Sep;21(5):631-41
references: 20562626
references: Environ Health Perspect. 2006 Aug;114(8):1287-92
references: 16882541
references: J Health Econ. 2009 May;28(3):688-703
references: 19328569
references: J Neurosci. 2009 Feb 18;29(7):2089-102
references: 19228962
references: J Clin Invest. 2009 Apr;119(4):747-54
references: 19339766
references: FASEB J. 2009 Aug;23(8):2374-83
references: 19307255
references: J Neuroimmunol. 2009 Feb 15;207(1-2):111-6
references: 19157572
references: J Neuroimmunol. 2008 Nov 15;204(1-2):149-53
references: 18762342
references: Trends Neurosci. 2009 Sep;32(9):506-16
references: 19716187
references: Ann Neurol. 2007 Sep;62(3):243-50
references: 17696172
references: Environ Health Perspect. 2009 Dec;117(12):1919-24
references: 20049212
references: J Nanosci Nanotechnol. 2009 Aug;9(8):5099-104
references: 19928188
references: PLoS One. 2010 Feb 08;5(2):e9096
references: 20161713
references: Lancet. 2004 Jan 10;363(9403):119-25
references: 14726165
references: Environ Health Perspect. 2006 Jul;114(7):1119-25
references: 16835068
references: Part Fibre Toxicol. 2008 Mar 11;5:3
references: 18331653
references: ALTEX. 2008;25(3):191-6
references: 18841315
references: Environ Health Perspect. 2006 Sep;114(9):1438-44
references: 16966102
references: Brain Behav Immun. 2009 Mar;23(3):389-95
references: 19136055
references: Environ Health Perspect. 2011 Jun;119(6):873-7
references: 21156395
references: Environ Health Perspect. 2008 Mar;116(3):362-9
references: 18335104
references: MMWR Surveill Summ. 2009 Dec 18;58(10):1-20
references: 20023608
references: Neuroimmunomodulation. 2002-2003;10(6):319-27
references: 12907838
references: J Nanosci Nanotechnol. 2009 Aug;9(8):4996-5007
references: 19928180
references: J Air Waste Manag Assoc. 2002 Sep;52(9):1032-42
references: 12269664