title: Perinatal Exposure to Traffic-Related Air Pollution and Atopy at 1 Year of Age in a Multi-Center Canadian Birth Cohort Study.
abstract: BACKGROUND
  The role of traffic-related air pollution (TRAP) exposure in the development of allergic sensitization in children is unclear, and few birth cohort studies have incorporated spatiotemporal exposure assessment.
  
  
  OBJECTIVE
  We aimed to examine the association between TRAP and atopy in 1-year-old children from an ongoing national birth cohort study in four Canadian cities.
  
  
  METHODS
  We identified 2,477 children of approximately 1 year of age with assessment of atopy for inhalant (Alternaria, Der p, Der f, cat, dog, cockroach) and food-related (milk, eggs, peanuts, soy) allergens. Exposure to nitrogen dioxide (NO2) was estimated from city-specific land use regression models accounting for residential mobility and temporal variability in ambient concentrations. We used mixed models to examine associations between atopy and exposure during pregnancy and the first year of life, including adjustment for covariates (maternal atopy, socioeconomic status, pets, mold, nutrition). We also conducted analyses stratified by time-location patterns, daycare attendance, and modeled home ventilation.
  
  
  RESULTS
  Following spatiotemporal adjustment, TRAP exposure after birth increased the risk for development of atopy to any allergens [adjusted odds ratio (aOR) per 10 μg/m3 NO2 = 1.16; 95% CI: 1.00, 1.41], but not during pregnancy (aOR = 1.02; 95% CI: 0.86, 1.22). This association was stronger among children not attending daycare (aOR = 1.61; 95% CI: 1.28, 2.01) compared with daycare attendees (aOR = 1.05; 95% CI: 0.81, 1.28). Trends to increased risk were also found for food (aOR = 1.17; 95% CI: 0.95, 1.47) and inhalant allergens (aOR = 1.28; 95% CI: 0.93, 1.76).
  
  
  CONCLUSIONS
  Using refined exposure estimates that incorporated temporal variability and residential mobility, we found that traffic-related air pollution during the first year of life was associated with atopy.
  
  
  BACKGROUND
  Sbihi H, Allen RW, Becker A, Brook JR, Mandhane P, Scott JA, Sears MR, Subbarao P, Takaro TK, Turvey SE, Brauer M. 2015. Perinatal exposure to traffic-related air pollution and atopy at 1 year of age in a multi-center Canadian birth cohort study. Environ Health Perspect 123:902-908; http://dx.doi.org/10.1289/ehp.1408700.
authors.affiliation: School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Hind
authors.initials: H
authors.lastname: Sbihi
authors.forename: Ryan W
authors.initials: RW
authors.lastname: Allen
authors.forename: Allan
authors.initials: A
authors.lastname: Becker
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Brook
authors.forename: Piush
authors.initials: P
authors.lastname: Mandhane
authors.forename: James A
authors.initials: JA
authors.lastname: Scott
authors.forename: Malcolm R
authors.initials: MR
authors.lastname: Sears
authors.forename: Padmaja
authors.initials: P
authors.lastname: Subbarao
authors.forename: Tim K
authors.initials: TK
authors.lastname: Takaro
authors.forename: Stuart E
authors.initials: SE
authors.lastname: Turvey
authors.forename: Michael
authors.initials: M
authors.lastname: Brauer
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects*; D000397:Air Pollution / Q000009:adverse effects*; D002170:Canada; D002947:Cities; D015331:Cohort Studies; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology* / Q000276:immunology; D007223:Infant; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D009585:Nitrogen Dioxide / Q000009:adverse effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology* / Q000209:etiology; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D009585:Nitrogen Dioxide
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