title: Timing and Duration of Traffic-related Air Pollution Exposure and the Risk for Childhood Wheeze and Asthma.
abstract: BACKGROUND
  The timing and duration of traffic-related air pollution (TRAP) exposure may be important for childhood wheezing and asthma development.
  
  
  OBJECTIVE
  We examined the relationship between TRAP exposure and longitudinal wheezing phenotypes and asthma at age 7 years.
  
  
  METHODS
  Children completed clinical examinations annually from age 1 year through age 4 years and age 7 years. Parental-reported wheezing was assessed at each age, and longitudinal wheezing phenotypes (early-transient, late-onset, persistent) and asthma were defined at age 7 years. Participants' time-weighted exposure to TRAP, from birth through age 7 years, was estimated using a land-use regression model. The relationship between TRAP exposure and wheezing phenotypes and asthma was examined.
  
  
  RESULTS
  High TRAP exposure at birth was significantly associated with both transient and persistent wheezing phenotypes (adjusted odds ratio [aOR] = 1.64; 95% confidence interval [CI], 1.04-2.57 and aOR = 2.31; 95% CI, 1.28-4.15, respectively); exposure from birth to age 1 year and age 1 to 2 years was also associated with persistent wheeze. Only children with high average TRAP exposure from birth through age 7 years were at significantly increased risk for asthma (aOR = 1.71; 95% CI, 1.01-2.88).
  
  
  CONCLUSIONS
  Early-life exposure to TRAP is associated with increased risk for persistent wheezing, but only long-term exposure to high levels of TRAP throughout childhood was associated with asthma development.
authors.affiliation: 1 Department of Pediatrics and.|2 Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Brunst
authors.affiliation: 3 Division of Biostatistics and Epidemiology and.|4 Department of Environmental Health and.
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Ryan
authors.affiliation: 4 Department of Environmental Health and.
authors.forename: Cole
authors.initials: C
authors.lastname: Brokamp
authors.affiliation: 5 Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio.
authors.forename: David
authors.initials: D
authors.lastname: Bernstein
authors.affiliation: 4 Department of Environmental Health and.
authors.forename: Tiina
authors.initials: T
authors.lastname: Reponen
authors.affiliation: 4 Department of Environmental Health and.|5 Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio.
authors.forename: James
authors.initials: J
authors.lastname: Lockey
authors.affiliation: 6 Division of Asthma Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; and.
authors.forename: Gurjit K
authors.initials: GK
authors.lastname: Khurana Hershey
authors.affiliation: 4 Department of Environmental Health and.
authors.forename: Linda
authors.initials: L
authors.lastname: Levin
authors.affiliation: 4 Department of Environmental Health and.
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Grinshpun
authors.affiliation: 6 Division of Asthma Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; and.|4 Department of Environmental Health and.
authors.forename: Grace
authors.initials: G
authors.lastname: LeMasters
mesh_terms: D000367:Age Factors; D000393:Air Pollutants / Q000009:adverse effects*; D000397:Air Pollution / Q000009:adverse effects*; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D012135:Respiratory Sounds / Q000209:etiology*; D012307:Risk Factors; D013997:Time Factors; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions
keywords: air pollution; asthma; childhood; persistent wheeze