title: Long-Term Exposure to Primary Traffic Pollutants and Lung Function in Children: Cross-Sectional Study and Meta-Analysis.
abstract: BACKGROUND
  There is widespread concern about the possible health effects of traffic-related air pollution. Nitrogen dioxide (NO2) is a convenient marker of primary pollution. We investigated the associations between lung function and current residential exposure to a range of air pollutants (particularly NO2, NO, NOx and particulate matter) in London children. Moreover, we placed the results for NO2 in context with a meta-analysis of published estimates of the association.
  
  
  RESULTS
  Associations between primary traffic pollutants and lung function were investigated in 4884 children aged 9-10 years who participated in the Child Heart and Health Study in England (CHASE). A systematic literature search identified 13 studies eligible for inclusion in a meta-analysis. We combined results from the meta-analysis with the distribution of the values of FEV1 in CHASE to estimate the prevalence of children with abnormal lung function (FEV1<80% of predicted value) expected under different scenarios of NO2 exposure. In CHASE, there were non-significant inverse associations between all pollutants except ozone and both FEV1 and FVC. In the meta-analysis, a 10 μg/m3 increase in NO2 was associated with an 8 ml lower FEV1 (95% CI: -14 to -1 ml; p: 0.016). The observed effect was not modified by a reported asthma diagnosis. On the basis of these results, a 10 μg/m3 increase in NO2 level would translate into a 7% (95% CI: 4% to 12%) increase of the prevalence of children with abnormal lung function.
  
  
  CONCLUSIONS
  Exposure to traffic pollution may cause a small overall reduction in lung function and increase the prevalence of children with clinically relevant declines in lung function.
authors.affiliation: MRC-PHE Centre for Environment and Health, Population Health Research Institute, St George's, University of London, London, United Kingdom.
authors.forename: Francesco
authors.initials: F
authors.lastname: Barone-Adesi
authors.affiliation: MRC-PHE Centre for Environment and Health, Population Health Research Institute, St George's, University of London, London, United Kingdom.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Dent
authors.affiliation: MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Dajnak
authors.affiliation: MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
authors.forename: Sean
authors.initials: S
authors.lastname: Beevers
authors.affiliation: MRC-PHE Centre for Environment and Health, Population Health Research Institute, St George's, University of London, London, United Kingdom.|MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
authors.forename: H Ross
authors.initials: HR
authors.lastname: Anderson
authors.affiliation: MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Kelly
authors.affiliation: MRC-PHE Centre for Environment and Health, Population Health Research Institute, St George's, University of London, London, United Kingdom.
authors.forename: Derek G
authors.initials: DG
authors.lastname: Cook
authors.affiliation: MRC-PHE Centre for Environment and Health, Population Health Research Institute, St George's, University of London, London, United Kingdom.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Whincup
mesh_terms: D000397:Air Pollution; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D005260:Female; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D008297:Male; D009585:Nitrogen Dioxide / Q000633:toxicity; D052638:Particulate Matter / Q000633:toxicity; D012123:Pulmonary Ventilation; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D052638:Particulate Matter; D001335:Vehicle Emissions; D009585:Nitrogen Dioxide