title: Early life exposure to traffic-related air pollution and allergic rhinitis in preschool children.
abstract: Evidence linking long-term exposure to outdoor air pollution with allergic rhinitis (AR) in children is scare, and the role of components of air pollution and timing of exposure remains unclear.
  
  
  
  To assess the association of pre- and post-natal exposure to air pollution with life-time prevalence of AR in preschool children.
  
  
  
  We conducted a cohort study of 2598 children aged 3-6 years in Changsha, China. The lifetime prevalence of AR was assessed by a questionnaire administered by parents. Children's exposures to dioxide nitrogen (NO2), sulfur dioxide (SO2) and particulate matter with an aerodynamic diameter ≤ 10 μm (PM10) during different pre- and post-natal timing windows were estimated using the measured concentrations at monitoring stations. The odds ratio (OR) and 95% confidence interval (CI) of childhood AR for exposure to different air pollutants during different timing windows were assessed by logistic regression model in terms of an interquartile range (IQR) increase in exposure level.
  
  
  
  Life-time prevalence of AR in preschool children (7.3%) was associated with both pre- and post-natal exposure to traffic-related air pollution (TRAP), but only significant during the third trimester of pregnancy with adjusted OR = 1.40 (95% CI: 1.08-1.82) for a 15 μg/m3increase in NO2and during the first-year of life with adjusted OR = 1.36 (95% CI: 1.03-1.78) and 1.54 (95% CI: 1.07-2.21) respectively for 11 and 12 μg/m3increase in NO2and PM10. The association of early life exposure to TRAP with childhood AR was robust by adjusting for other air pollutants and timing windows. Sensitivity analysis indicated that the association was higher in the children who are male, young, with genetic predisposition by parental atopy, and living in damp houses.
  
  
  
  Early life exposure to traffic-related air pollutant during pregnancy and first-year of life may contribute to childhood AR.
authors.affiliation: School of Energy Science and Engineering, Central South University, Changsha, Hunan, China; XiangYa School of Public Health, Central South University, Changsha, Hunan, China. Electronic address: qhdeng@csu.edu.cn.
authors.forename: Qihong
authors.initials: Q
authors.lastname: Deng
authors.affiliation: School of Energy Science and Engineering, Central South University, Changsha, Hunan, China.
authors.forename: Chan
authors.initials: C
authors.lastname: Lu
authors.affiliation: School of Energy Science and Engineering, Central South University, Changsha, Hunan, China.
authors.forename: Yichen
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
authors.forename: Yuguo
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Energy Science and Engineering, Central South University, Changsha, Hunan, China; School of Architecture, Tsinghua University, Beijing, China.
authors.forename: Jan
authors.initials: J
authors.lastname: Sundell
authors.affiliation: School of Energy Science and Engineering, Central South University, Changsha, Hunan, China; Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Dan
authors.initials: D
authors.lastname: Norbäck
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects / Q000032:analysis; D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D018986:Motor Vehicles; D009585:Nitrogen Dioxide / Q000009:adverse effects / Q000032:analysis; D052638:Particulate Matter / Q000009:adverse effects / Q000032:analysis; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology / Q000209:etiology; D015995:Prevalence; D065631:Rhinitis, Allergic / Q000453:epidemiology* / Q000209:etiology*; D013458:Sulfur Dioxide / Q000009:adverse effects / Q000032:analysis
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D013458:Sulfur Dioxide; D009585:Nitrogen Dioxide
keywords: Air pollution; Allergic disease; Children health; First-year of life; Pregnancy; Rhinitis