The effect of dose and timing of dose on the association between airborne particles and survival

Schwartz, J; Coull, B; Laden, F; Ryan, L

The effect of dose and timing of dose on the association between airborne particles and survival

Schwartz, J Coull, B Laden, F Ryan, L

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Publication Type:: Journal Article
Citation:: Environmental Health Perspectives, 2008, 116 (1), pp. 64 - 69
Issue Date:: 2008-01-01

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Field	Value	Language
dc.contributor.author	Schwartz, J	en_US
dc.contributor.author	Coull, B	en_US
dc.contributor.author	Laden, F	en_US
dc.contributor.author	Ryan, L https://orcid.org/0000-0001-5957-2490	en_US
dc.date.available	2007-10-04	en_US
dc.date.issued	2008-01-01	en_US
dc.identifier.citation	Environmental Health Perspectives, 2008, 116 (1), pp. 64 - 69	en_US
dc.identifier.issn	0091-6765	en_US
dc.identifier.uri	http://hdl.handle.net/10453/88310
dc.description.abstract	Background: Understanding the shape of the concentration-response curve for particles is important for public health, and lack of such understanding was recently cited by U.S. Environmental Protection Agency (EPA) as a reason for not tightening the standards. Similarly, the delay between changes in exposure and changes in health is also important in public health decision making. We addressed these issues using an extended follow-up of the Harvard Six Cities Study. Methods: Cox proportional hazards models were fit controlling for smoking, body mass index, and other covariates. Two approaches were used. First, we used penalized splines, which fit a flexible functional form to the concentration response to examine its shape, and chose the degrees of freedom for the curve based on Akaike's information criterion. Because the uncertainties around the resultant curve do not reflect the uncertainty in model choice, we also used model averaging as an alternative approach, where multiple models are fit explicitly and averaged, weighted by their probability of being correct given the data. We examined the lag relationship by model averaging across a range of unconstrained distributed lag models. Results: We found that the concentration-response curve is linear, clearly continuing below the current U.S. standard of 15 μg/m3, and that the effects of changes in exposure on mortality are seen within two years. Conclusions: Reduction in particle concentrations below U.S. EPA standards would increase life expectancy.	en_US
dc.relation.ispartof	Environmental Health Perspectives	en_US
dc.relation.isbasedon	10.1289/ehp.9955	en_US
dc.subject.classification	Toxicology	en_US
dc.subject.mesh	Humans	en_US
dc.subject.mesh	Air Pollutants	en_US
dc.subject.mesh	Survival Rate	en_US
dc.subject.mesh	Data Interpretation, Statistical	en_US
dc.subject.mesh	Models, Statistical	en_US
dc.subject.mesh	Dose-Response Relationship, Drug	en_US
dc.subject.mesh	Adult	en_US
dc.subject.mesh	United States	en_US
dc.subject.mesh	Particulate Matter	en_US
dc.title	The effect of dose and timing of dose on the association between airborne particles and survival	en_US
dc.type	Journal Article
utslib.citation.volume	1	en_US
utslib.citation.volume	116	en_US
utslib.for	010402 Biostatistics	en_US
utslib.for	05 Environmental Sciences	en_US
utslib.for	11 Medical and Health Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
utslib.copyright.status	closed_access
pubs.issue	1	en_US
pubs.publication-status	Published	en_US
pubs.volume	116	en_US

Abstract:

Background: Understanding the shape of the concentration-response curve for particles is important for public health, and lack of such understanding was recently cited by U.S. Environmental Protection Agency (EPA) as a reason for not tightening the standards. Similarly, the delay between changes in exposure and changes in health is also important in public health decision making. We addressed these issues using an extended follow-up of the Harvard Six Cities Study. Methods: Cox proportional hazards models were fit controlling for smoking, body mass index, and other covariates. Two approaches were used. First, we used penalized splines, which fit a flexible functional form to the concentration response to examine its shape, and chose the degrees of freedom for the curve based on Akaike's information criterion. Because the uncertainties around the resultant curve do not reflect the uncertainty in model choice, we also used model averaging as an alternative approach, where multiple models are fit explicitly and averaged, weighted by their probability of being correct given the data. We examined the lag relationship by model averaging across a range of unconstrained distributed lag models. Results: We found that the concentration-response curve is linear, clearly continuing below the current U.S. standard of 15 μg/m3, and that the effects of changes in exposure on mortality are seen within two years. Conclusions: Reduction in particle concentrations below U.S. EPA standards would increase life expectancy.

Please use this identifier to cite or link to this item:

http://hdl.handle.net/10453/26051