Cargando…
Potential Confounding of Particulate Matter on the Short-Term Association between Ozone and Mortality in Multisite Time-Series Studies
BACKGROUND: A critical question regarding the association between short-term exposure to ozone and mortality is the extent to which this relationship is confounded by ambient exposure to particles. OBJECTIVES: We investigated whether particulate matter < 10 and < 2.5 μm in aerodynamic diameter...
Autores principales: | , , |
---|---|
Formato: | Texto |
Lenguaje: | English |
Publicado: |
National Institute of Environmental Health Sciences
2007
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2072830/ https://www.ncbi.nlm.nih.gov/pubmed/18007990 http://dx.doi.org/10.1289/ehp.10108 |
_version_ | 1782137791227887616 |
---|---|
author | Bell, Michelle L. Kim, Jee Young Dominici, Francesca |
author_facet | Bell, Michelle L. Kim, Jee Young Dominici, Francesca |
author_sort | Bell, Michelle L. |
collection | PubMed |
description | BACKGROUND: A critical question regarding the association between short-term exposure to ozone and mortality is the extent to which this relationship is confounded by ambient exposure to particles. OBJECTIVES: We investigated whether particulate matter < 10 and < 2.5 μm in aerodynamic diameter (PM(10) and PM(2.5)) is a confounder of the ozone and mortality association using data for 98 U.S. urban communities from 1987 to 2000. METHODS: We a) estimated correlations between daily ozone and daily PM concentrations stratified by ozone or PM levels; b) included PM as a covariate in time-series models; and c) included PM as a covariate as in d), but within a subset approach considering only days with ozone below a specified value. RESULTS: Analysis was hindered by data availability. In the 93 communities with PM(10) data, only 25.0% of study days had data on both ozone and PM(10). In the 91 communities with PM(2.5) data, only 9.2% of days in the study period had data on ozone and PM(2.5). Neither PM measure was highly correlated with ozone at any level of ozone or PM. National and community-specific effect estimates of the short-term effects of ozone on mortality were robust to inclusion of PM(10) or PM(2.5) in time-series models. The robustness remains even at low ozone levels (< 10 ppb) using a subset approach. CONCLUSIONS: Results provide evidence that neither PM(10) nor PM(2.5) is a likely confounder of observed ozone and mortality relationships. Further investigation is needed to investigate potential confounding of the short-term effects of ozone on mortality by PM chemical composition. |
format | Text |
id | pubmed-2072830 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2007 |
publisher | National Institute of Environmental Health Sciences |
record_format | MEDLINE/PubMed |
spelling | pubmed-20728302007-11-14 Potential Confounding of Particulate Matter on the Short-Term Association between Ozone and Mortality in Multisite Time-Series Studies Bell, Michelle L. Kim, Jee Young Dominici, Francesca Environ Health Perspect Research BACKGROUND: A critical question regarding the association between short-term exposure to ozone and mortality is the extent to which this relationship is confounded by ambient exposure to particles. OBJECTIVES: We investigated whether particulate matter < 10 and < 2.5 μm in aerodynamic diameter (PM(10) and PM(2.5)) is a confounder of the ozone and mortality association using data for 98 U.S. urban communities from 1987 to 2000. METHODS: We a) estimated correlations between daily ozone and daily PM concentrations stratified by ozone or PM levels; b) included PM as a covariate in time-series models; and c) included PM as a covariate as in d), but within a subset approach considering only days with ozone below a specified value. RESULTS: Analysis was hindered by data availability. In the 93 communities with PM(10) data, only 25.0% of study days had data on both ozone and PM(10). In the 91 communities with PM(2.5) data, only 9.2% of days in the study period had data on ozone and PM(2.5). Neither PM measure was highly correlated with ozone at any level of ozone or PM. National and community-specific effect estimates of the short-term effects of ozone on mortality were robust to inclusion of PM(10) or PM(2.5) in time-series models. The robustness remains even at low ozone levels (< 10 ppb) using a subset approach. CONCLUSIONS: Results provide evidence that neither PM(10) nor PM(2.5) is a likely confounder of observed ozone and mortality relationships. Further investigation is needed to investigate potential confounding of the short-term effects of ozone on mortality by PM chemical composition. National Institute of Environmental Health Sciences 2007-11 2007-08-02 /pmc/articles/PMC2072830/ /pubmed/18007990 http://dx.doi.org/10.1289/ehp.10108 Text en http://creativecommons.org/publicdomain/mark/1.0/ 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. |
spellingShingle | Research Bell, Michelle L. Kim, Jee Young Dominici, Francesca Potential Confounding of Particulate Matter on the Short-Term Association between Ozone and Mortality in Multisite Time-Series Studies |
title | Potential Confounding of Particulate Matter on the Short-Term Association between Ozone and Mortality in Multisite Time-Series Studies |
title_full | Potential Confounding of Particulate Matter on the Short-Term Association between Ozone and Mortality in Multisite Time-Series Studies |
title_fullStr | Potential Confounding of Particulate Matter on the Short-Term Association between Ozone and Mortality in Multisite Time-Series Studies |
title_full_unstemmed | Potential Confounding of Particulate Matter on the Short-Term Association between Ozone and Mortality in Multisite Time-Series Studies |
title_short | Potential Confounding of Particulate Matter on the Short-Term Association between Ozone and Mortality in Multisite Time-Series Studies |
title_sort | potential confounding of particulate matter on the short-term association between ozone and mortality in multisite time-series studies |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2072830/ https://www.ncbi.nlm.nih.gov/pubmed/18007990 http://dx.doi.org/10.1289/ehp.10108 |
work_keys_str_mv | AT bellmichellel potentialconfoundingofparticulatematterontheshorttermassociationbetweenozoneandmortalityinmultisitetimeseriesstudies AT kimjeeyoung potentialconfoundingofparticulatematterontheshorttermassociationbetweenozoneandmortalityinmultisitetimeseriesstudies AT dominicifrancesca potentialconfoundingofparticulatematterontheshorttermassociationbetweenozoneandmortalityinmultisitetimeseriesstudies |