American Journal of Epidemiology Advance Access published online on May 7, 2008
American Journal of Epidemiology, doi:10.1093/aje/kwn087
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Original Contribution |
Air Pollution, Asthma Attacks, and Socioeconomic Deprivation: A Small-Area Case-Crossover Study
1 Health and Environment Research Laboratory (LERES), French School of Advanced Studies in Public Health (EHESP), Rennes, France
2 SEPIA-Santé, Baud, France
3 French National Institute of Health Surveillance (InVS), Bordeaux Cedex, France
4 Department for Assessment and Management of Risks Related to the Environment and the Health System (EGERIES), French School of Advanced Studies in Public Health (EHESP), Rennes, France
5 Association for Air Pollution Surveillance and Study in Alsace (ASPA), Schiltigheim, France
Correspondence to Dr. Denis Bard, Laboratoire d'études et de recherche en environnement et santé, Ecole des hautes études en santé publique, Avenue du Pr. Léon Bernard, 35043 Rennes, France (e-mail: denis.bard{at}ehesp.fr).
Received for publication January 17, 2008. Accepted for publication March 17, 2008.
With few exceptions, studies of short-term health effects of air pollution use pollutant concentrations that are averaged citywide as exposure indicators. They are thus prone to exposure misclassification and consequently to bias. Measurement of the relations between air pollution and health, generally and in specific populations, could be improved by employing more geographically precise exposure estimates. The authors investigated short-term relations between ambient air pollution estimated in small geographic areas (French census blocks) and asthma attacks in Strasbourg, France, in 2000–2005—in the general population and in populations with contrasting levels of socioeconomic deprivation. Emergency health-care networks provided data on 4,683 telephone calls made for asthma attacks. Deprivation was estimated using a block-level index constructed from census data. Hourly concentrations of particulate matter less than 10 µm in aerodynamic diameter (PM10), sulfur dioxide, nitrogen dioxide, and ozone were modeled by block with ADMS-Urban software. Adjusted case-crossover analyses showed that asthma calls were positively but not significantly associated with PM10 (for a 10-µg x m–3 increase, odds ratio (OR) = 1.035, 95% confidence interval (CI): 0.997, 1.075), sulfur dioxide (OR = 1.056, 95% CI: 0.979, 1.139), and nitrogen dioxide (OR = 1.025, 95% CI: 0.990, 1.062). No association was observed for ozone (OR = 0.998, 95% CI: 0.965, 1.032). Socioeconomic deprivation had no significant influence on these relations.
air pollution; asthma; effect modifiers (epidemiology); environmental exposure; particulate matter; small-area analysis; socioeconomic factors; urban population
Abbreviations: CI, confidence interval; OR, odds ratio; PM10, particulate matter less than 10 µm in aerodynamic diameter; SAMU, Service d'Aide Médicale d'Urgence; SMA, Strasbourg metropolitan area