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Association of short-term increases in ambient air pollution and timing of initial asthma diagnosis among Medicaid-enrolled children in a metropolitan area.
- Source :
-
Environmental research [Environ Res] 2014 May; Vol. 131, pp. 50-8. Date of Electronic Publication: 2014 Mar 20. - Publication Year :
- 2014
-
Abstract
- Objective: We investigated associations of short-term changes in ambient ozone (O3), fine particulate matter (PM2.5) and nitrogen dioxide (NO2) concentrations and the timing of new-onset asthma, using a large, high-risk population in an area with historically high ozone levels.<br />Methods: The study population included 18,289 incident asthma cases identified among Medicaid-enrolled children in Harris County Texas between 2005-2007, using Medicaid Analytic Extract enrollment and claims files. We used a time-stratified case-crossover design and conditional logistic regression to assess the effect of increased short-term pollutant concentrations on the timing of asthma onset.<br />Results: Each 10 ppb increase in ozone was significantly associated with new-onset asthma during the warm season (May-October), with the strongest association seen when a 6-day cumulative average period was used as the exposure metric (odds ratio [OR]=1.05, 95% confidence interval [CI], 1.02-1.08). Similar results were seen for NO2 and PM2.5 (OR=1.07, 95% CI, 1.03-1.11 and OR=1.12, 95% CI, 1.03-1.22, respectively), and PM2.5 also had significant effects in the cold season (November-April), 5-day cumulative lag (OR=1.11. 95% CI, 1.00-1.22). Significantly increased ORs for O3 and NO2 during the warm season persisted in co-pollutant models including PM2.5. Race and age at diagnosis modified associations between ozone and onset of asthma.<br />Conclusion: Our results indicate that among children in this low-income urban population who developed asthma, their initial date of diagnosis was more likely to occur following periods of higher short-term ambient pollutant levels.<br /> (Copyright © 2014 Elsevier Inc. All rights reserved.)
Details
- Language :
- English
- ISSN :
- 1096-0953
- Volume :
- 131
- Database :
- MEDLINE
- Journal :
- Environmental research
- Publication Type :
- Academic Journal
- Accession number :
- 24657516
- Full Text :
- https://doi.org/10.1016/j.envres.2014.02.013