Ambient air pollution triggers wheezing symptoms in infants.
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 microm in diameter (PM(10)) and the concentrations of ultrafine particles, nitrogen dioxide (NO(2)), nitrogen oxide (NO(x)) 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 PM(10), NO(2), NO(x), CO and wheezing symptoms in infants (aged 0-1 year) with a delay of 3-4 days. Only the traffic-related gases (NO(2), NO(x)) 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.
Andersen
Z J
ZJ
Department of Biostatistics, Institute of Public Health, Copenhagen University, Øster Farimagsgade 5 Entr. B, P O Box 2099, 1014 Copenhagen K, Denmark. zorana@cancer.dk
Loft
S
S
Ketzel
M
M
Stage
M
M
Scheike
T
T
Hermansen
M N
MN
Bisgaard
H
H
D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D001249:Asthma / Q000235:genetics; D002248:Carbon Monoxide / Q000633:toxicity; D002675:Child, Preschool; D003718:Denmark; D004812:Epidemiologic Methods; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007223:Infant; D008297:Male; D009585:Nitrogen Dioxide / Q000032:analysis / Q000633:toxicity; D009589:Nitrogen Oxides / Q000032:analysis / Q000633:toxicity; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity; D010375:Pedigree; D011446:Prospective Studies; D012135:Respiratory Sounds / Q000209:etiology*; D013997:Time Factors; D001335:Vehicle Emissions / Q000032:analysis / Q000633:toxicity
D000393:Air Pollutants; D009589:Nitrogen Oxides; D052638:Particulate Matter; D001335:Vehicle Emissions; D002248:Carbon Monoxide; D009585:Nitrogen Dioxide