Outdoor air pollution and emergency department visits for asthma among children and adults: A case-crossover study in northern Alberta, Canada

<p>Abstract</p> <p>Background</p> <p>Recent studies have observed positive associations between outdoor air pollution and emergency department (ED) visits for asthma. However, few have examined the possible confounding influence of aeroallergens, or reported findings am...

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Main Authors: Rowe Brian H, Chen Li, Villeneuve Paul J, Coates Frances
Format: Article
Language:English
Published: BMC 2007-12-01
Series:Environmental Health
Online Access:http://www.ehjournal.net/content/6/1/40
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author Rowe Brian H
Chen Li
Villeneuve Paul J
Coates Frances
author_facet Rowe Brian H
Chen Li
Villeneuve Paul J
Coates Frances
author_sort Rowe Brian H
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Recent studies have observed positive associations between outdoor air pollution and emergency department (ED) visits for asthma. However, few have examined the possible confounding influence of aeroallergens, or reported findings among very young children.</p> <p>Methods</p> <p>A time stratified case-crossover design was used to examine 57,912 ED asthma visits among individuals two years of age and older in the census metropolitan area of Edmonton, Canada between April 1, 1992 and March 31, 2002. Daily air pollution levels for the entire region were estimated from three fixed-site monitoring stations. Similarly, daily levels of aeroallergens were estimated using rotational impaction sampling methods for the period between 1996 and 2002. Odds ratios and their corresponding 95% confidence intervals were estimated using conditional logistic regression with adjustment for temperature, relative humidity and seasonal epidemics of viral related respiratory disease.</p> <p>Results</p> <p>Positive associations for asthma visits with outdoor air pollution levels were observed between April and September, but were absent during the remainder of the year. Effects were strongest among young children. Namely, an increase in the interquartile range of the 5-day average for NO<sub>2 </sub>and CO levels between April and September was associated with a 50% and 48% increase, respectively, in the number of ED visits among children 2 – 4 years of age (p < 0.05). Strong associations were also observed with these pollutants among those 75 years of age and older. Ozone and particulate matter were also associated with asthma visits. Air pollution risk estimates were largely unchanged after adjustment for aeroallergen levels.</p> <p>Conclusion</p> <p>Our findings, taken together, suggest that exposure to ambient levels of air pollution is an important determinant of ED visits for asthma, particularly among young children and the elderly.</p>
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spelling doaj.art-24395246823a459f836255f496fa51272022-12-21T19:01:44ZengBMCEnvironmental Health1476-069X2007-12-01614010.1186/1476-069X-6-40Outdoor air pollution and emergency department visits for asthma among children and adults: A case-crossover study in northern Alberta, CanadaRowe Brian HChen LiVilleneuve Paul JCoates Frances<p>Abstract</p> <p>Background</p> <p>Recent studies have observed positive associations between outdoor air pollution and emergency department (ED) visits for asthma. However, few have examined the possible confounding influence of aeroallergens, or reported findings among very young children.</p> <p>Methods</p> <p>A time stratified case-crossover design was used to examine 57,912 ED asthma visits among individuals two years of age and older in the census metropolitan area of Edmonton, Canada between April 1, 1992 and March 31, 2002. Daily air pollution levels for the entire region were estimated from three fixed-site monitoring stations. Similarly, daily levels of aeroallergens were estimated using rotational impaction sampling methods for the period between 1996 and 2002. Odds ratios and their corresponding 95% confidence intervals were estimated using conditional logistic regression with adjustment for temperature, relative humidity and seasonal epidemics of viral related respiratory disease.</p> <p>Results</p> <p>Positive associations for asthma visits with outdoor air pollution levels were observed between April and September, but were absent during the remainder of the year. Effects were strongest among young children. Namely, an increase in the interquartile range of the 5-day average for NO<sub>2 </sub>and CO levels between April and September was associated with a 50% and 48% increase, respectively, in the number of ED visits among children 2 – 4 years of age (p < 0.05). Strong associations were also observed with these pollutants among those 75 years of age and older. Ozone and particulate matter were also associated with asthma visits. Air pollution risk estimates were largely unchanged after adjustment for aeroallergen levels.</p> <p>Conclusion</p> <p>Our findings, taken together, suggest that exposure to ambient levels of air pollution is an important determinant of ED visits for asthma, particularly among young children and the elderly.</p>http://www.ehjournal.net/content/6/1/40
spellingShingle Rowe Brian H
Chen Li
Villeneuve Paul J
Coates Frances
Outdoor air pollution and emergency department visits for asthma among children and adults: A case-crossover study in northern Alberta, Canada
Environmental Health
title Outdoor air pollution and emergency department visits for asthma among children and adults: A case-crossover study in northern Alberta, Canada
title_full Outdoor air pollution and emergency department visits for asthma among children and adults: A case-crossover study in northern Alberta, Canada
title_fullStr Outdoor air pollution and emergency department visits for asthma among children and adults: A case-crossover study in northern Alberta, Canada
title_full_unstemmed Outdoor air pollution and emergency department visits for asthma among children and adults: A case-crossover study in northern Alberta, Canada
title_short Outdoor air pollution and emergency department visits for asthma among children and adults: A case-crossover study in northern Alberta, Canada
title_sort outdoor air pollution and emergency department visits for asthma among children and adults a case crossover study in northern alberta canada
url http://www.ehjournal.net/content/6/1/40
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