title: Air Pollution, Neighbourhood Socioeconomic Factors, and Neural Tube Defects in the San Joaquin Valley of California.
abstract: BACKGROUND
  Environmental pollutants and neighbourhood socioeconomic factors have been associated with neural tube defects, but the potential impact of interaction between ambient air pollution and neighbourhood socioeconomic factors on the risks of neural tube defects is not well understood.
  
  
  METHODS
  We used data from the California Center of the National Birth Defects Study and the Children's Health and Air Pollution Study to investigate whether associations between air pollutant exposure in early gestation and neural tube defects were modified by neighbourhood socioeconomic factors in the San Joaquin Valley of California, 1997-2006. There were 5 pollutant exposures, 3 outcomes, and 9 neighbourhood socioeconomic factors included for a total of 135 investigated associations. Estimates were adjusted for maternal race-ethnicity, education, and multivitamin use.
  
  
  RESULTS
  We present below odds ratios (ORs) that exclude 1 and a chi-square test of homogeneity P-value of <0.05. We observed increased odds of spina bifida comparing the highest to lowest quartile of particulate matter <10 μm (PM10 ) among those living in a neighbourhood with: (i) median household income of less than $30 000 per year [OR 5.1, 95% confidence interval (CI) 1.7, 15.3]; (ii) more than 20% living below the federal poverty level (OR 2.6, 95% CI 1.1, 6.0); and (iii) more than 30% with less than or equal to a high school education (OR 3.2, 95% CI 1.4, 7.4). The ORs were not statistically significant among those higher socioeconomic status (SES) neighbourhoods.
  
  
  CONCLUSIONS
  Our results demonstrate effect modification by neighbourhood socioeconomic factors in the association of particulate matter and neural tube defects in California.
authors.affiliation: Department of Pediatrics, Division of Neonatology, Stanford University, Stanford, CA.
authors.forename: Amy M
authors.initials: AM
authors.lastname: Padula
authors.affiliation: Department of Pediatrics, Division of Neonatology, Stanford University, Stanford, CA.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.affiliation: Department of Pediatrics, Division of Neonatology, Stanford University, Stanford, CA.
authors.forename: Suzan L
authors.initials: SL
authors.lastname: Carmichael
authors.affiliation: Division of Environmental Health Sciences, University of California, Berkeley, CA.
authors.forename: Ira B
authors.initials: IB
authors.lastname: Tager
authors.affiliation: Sonoma Technology, Inc., Petaluma, CA.
authors.forename: Frederick
authors.initials: F
authors.lastname: Lurmann
authors.affiliation: Division of Environmental Health Sciences, University of California, Berkeley, CA.
authors.forename: S Katharine
authors.initials: SK
authors.lastname: Hammond
authors.affiliation: Department of Pediatrics, Division of Neonatology, Stanford University, Stanford, CA.
authors.forename: Gary M
authors.initials: GM
authors.lastname: Shaw
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000009:adverse effects*; D002140:California / Q000453:epidemiology; D002248:Carbon Monoxide / Q000009:adverse effects; D002648:Child; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D009436:Neural Tube Defects / Q000139:chemically induced / Q000453:epidemiology* / Q000517:prevention & control; D009589:Nitrogen Oxides / Q000009:adverse effects; D010126:Ozone / Q000009:adverse effects; D052638:Particulate Matter / Q000009:adverse effects; D011159:Population Surveillance; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology* / Q000517:prevention & control; D012111:Residence Characteristics; D012959:Socioeconomic Factors; D001335:Vehicle Emissions / Q000633:toxicity
chemical_list: D000393:Air Pollutants; D009589:Nitrogen Oxides; D052638:Particulate Matter; D001335:Vehicle Emissions; D010126:Ozone; D002248:Carbon Monoxide
keywords: air pollution; neighbourhood; neural tube defects; socioeconomic status