Article Text

Download PDFPDF
Ambient air pollution triggers wheezing symptoms in infants
  1. Z J Andersen1,2,
  2. S Loft2,
  3. M Ketzel3,
  4. M Stage4,
  5. T Scheike1,
  6. M N Hermansen4,
  7. H Bisgaard4
  1. 1
    Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark
  2. 2
    Department of Environmental and Occupational Health, Copenhagen University, Copenhagen, Denmark
  3. 3
    Department of Atmospheric Environment, National Environmental Research Institute, Aarhus University, Denmark
  4. 4
    Danish Paediatric Asthma Centre, Copenhagen University Hospital, Gentofte, Copenhagen
  1. Mrs Z J Andersen, Department of Biostatistics, Institute of Public Health, Copenhagen University, Øster Farimagsgade 5 Entr. B, P O Box 2099, 1014 Copenhagen K, Denmark; zorana{at}


Background: There is limited evidence for the role of air pollution in the development and triggering of wheezing symptoms in young children. A study was undertaken to examine the effect of exposure to air pollution on wheezing symptoms in children under the age of 3 years with genetic susceptibility to asthma.

Methods: Daily recordings of symptoms were obtained for 205 children participating in the birth cohort study Copenhagen Prospective Study on Asthma in Children and living in Copenhagen for the first 3 years of life. Daily air pollution levels for particulate matter <10 μm in diameter (PM10) and the concentrations of ultrafine particles, nitrogen dioxide (NO2), nitrogen oxide (NOx) and carbon monoxide (CO) were available from a central background monitoring station in Copenhagen. The association between incident wheezing symptoms and air pollution on the concurrent and previous 4 days was estimated by a logistic regression model (generalised estimating equation) controlling for temperature, season, gender, age, exposure to smoking and paternal history of asthma.

Results: Significant positive associations were found between concentrations of PM10, NO2, NOx, CO and wheezing symptoms in infants (aged 0–1 year) with a delay of 3–4 days. Only the traffic-related gases (NO2, NOx) showed significant effects throughout the 3 years of life, albeit attenuating after the age of 1 year.

Conclusions: Air pollution related to traffic is significantly associated with triggering of wheezing symptoms in the first 3 years of life.

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Funding: The statistical analyses were supported by the Danish Research Council grant number 2052-03-16, AIRPOLIFE (Air Pollution in a Life Time Health Perspective) and the Danish Environmental Protection Agency. The COPSAC cohort study is funded by research funds from the Pharmacy Foundation of 1991; the Lundbeck Foundation; the Augustinus Foundation; Ronald McDonald House Charities; the Danish Medical Research Council; the Danish Pediatric Asthma Center; Direktør, cand. pharm. K Gad Andersen og Hustrus Familiefond; Aage Bangs Fond; Danish Lung Association; Kai Lange og Gunhild Kai Langes Fond; Direktør Ib Henriksens Fond; Gerda og Aage Hensch’s Fond; Rosalie Petersens Fond; Hans og Nora Buchards Fond; Dagmar Marshalls Fond; Foundation of Queen Louise Children Hospital; the Danish Hospital Foundation for Medical Research, Region of Copenhagen, the Faroe Island and Greenland; Gangsted Fond; Højmosegård-Legatet; Fonden til Lægevidenskabens Fremme; A P Møller og Hustru Chastine Mc-Kinney Møllers Fond til almene Formaal; The Danish Ministry of the Interior and Health’s Research Centre for Environmental Health. The study received support from the following pharmaceutical companies: AstraZenaca; LEOpharma; Pharmacia-Pfizer and Yamanouchi Pharma.

  • Competing interests: None.

  • Ethics approval: The COPSAC study was conducted in accordance with the Declaration of Helsinki and approved by the Copenhagen Ethics Committee and the Danish Data Protection Agency.