A case-crossover study of wintertime ambient air pollution and infant bronchiolitis.

Content Provider	Europe PMC
Author	Karr, Catherine Lumley, Thomas Shepherd, Kristen Davis, Robert Larson, Timothy Ritz, Beate Kaufman, Joel
Copyright Year	2006
Abstract	We examined the association of infant bronchiolitis with acute exposure to ambient air pollutants.DesignWe employed a time-stratified case–crossover method and based the exposure windows on a priori, biologically based hypotheses.ParticipantsWe evaluated effects in 19,901 infants in the South Coast Air Basin of California in 1995–2000 with a hospital discharge record for bronchiolitis in the first year of life (International Classification of Diseases, 9th Revision, CM466.1).Evaluations/MeasurementsStudy subjects’ ZIP code was linked to ambient air pollution monitors to derive exposures. We estimated the risk of bronchiolitis hospitalization associated with increases in wintertime ambient air pollutants using conditional logistic regression.ResultsWe observed no increased risk after acute exposure to particulate matter ≤ 2.5 μm in aerodynamic diameter (PM2.5), carbon monoxide, or nitrogen dioxide. PM2.5 exposure models suggested a 26–41% increased risk in the most premature infants born at gestational ages between 25 and 29 weeks; however, these findings were based on very small numbers.ConclusionsWe found little support for a link between acute increases in ambient air pollution and infant bronchiolitis except modestly increased risk for PM2.5 exposure among infants born very prematurely. In these infants, the periods of viral acquisition and incubation concurred with the time of increased risk.Relevance to Professional PracticeWe present novel data for the infant period and the key respiratory disease of infancy, bronchiolitis. Incompletely explained trends in rising bronchiolitis hospitalization rates and increasing number of infants born prematurely underscore the importance of evaluating the impact of ambient air pollution in this age group in other populations and studies.
ISSN	00916765
Journal	Environmental Health Perspectives
Volume Number	114
PubMed Central reference number	PMC1367844
Issue Number	2
PubMed reference number	16451867
e-ISSN	15529924
DOI	10.1289/ehp.8313
Language	English
Publisher	National Institute of Environmental Health Sciences
Publisher Date	2006-02-01
Access Restriction	Open
Rights License	Publication of EHP lies in the public domain and is therefore without copyright. All text from EHP may be reprinted freely. Use of materials published in EHP should be acknowledged (for example, ?Reproduced with permission from Environmental Health Perspectives?); pertinent reference information should be provided for the article from which the material was reproduced. Articles from EHP, especially the News section, may contain photographs or illustrations copyrighted by other commercial organizations or individuals that may not be used without obtaining prior approval from the holder of the copyright.
Subject Keyword	ambient air pollution bronchiolitis carbon monoxide case–crossover infant nitrogen dioxide particulate matter respiratory disease
Content Type	Text
Resource Type	Article
Subject	Health, Toxicology and Mutagenesis Public Health, Environmental and Occupational Health