The Effect of Dose and Timing of Dose on the Association between Airborne
Particles and Survival

The Effect of Dose and Timing of Dose on the Association between Airborne Particles and Survival

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The Effect of Dose and Timing of Dose on the Association between Airborne Particles and Survival

dc.contributor.author	Schwartz, Joel David
dc.contributor.author	Coull, Brent Andrew
dc.contributor.author	Laden, Francine
dc.contributor.author	Ryan, Louise Marie
dc.date.accessioned	2011-05-11T02:49:16Z
dc.date.issued	2008
dc.identifier.citation	Schwartz, Joel, Brent Coull, Francine Laden, and Louise Ryan. 2008. The Effect of Dose and Timing of Dose on the Association between Airborne Particles and Survival. Environmental Health Perspectives 116(1): 64-69.	en_US
dc.identifier.uri	http://nrs.harvard.edu/urn-3:HUL.InstRepos:4887121
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.language.iso	en_US	en_US
dc.relation.isversionof	doi:10.1289/ehp.9955	en_US
dash.license	LAA
dc.subject	air pollution	en_US
dc.subject	dose response	en_US
dc.subject	model averaging	en_US
dc.subject	particles	en_US
dc.subject	PM2.5	en_US
dc.subject	spline	en_US
dc.subject	survival	en_US
dc.subject	threshold	en_US
dc.subject	uncertainty	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	en_US
dc.description.version	Version of Record	en_US
dc.relation.journal	Environmental Health Perspectives	en_US
dash.depositing.author	Ryan, Louise Marie
dc.date.available	2011-05-11T02:49:16Z
dash.affiliation.other	HMS^Medicine-Brigham and Women's Hospital	en_US
dash.affiliation.other	SPH^Exposure Epidemiology and Risk Program	en_US
dash.affiliation.other	SPH^Biostatistics	en_US
dash.affiliation.other	HMS^Medicine-Brigham and Women's Hospital	en_US
dash.affiliation.other	SPH^Exposure Epidemiology and Risk Program	en_US
dash.affiliation.other	SPH^Biostatistics	en_US