Controlled human exposures to ambient pollutant particles in susceptible populations.
Abstract
Epidemiologic studies have established an association between exposures to air pollution
particles and human mortality and morbidity at concentrations of particles currently
found in major metropolitan areas. The adverse effects of pollution particles are
most prominent in susceptible subjects, including the elderly and patients with cardiopulmonary
diseases. Controlled human exposure studies have been used to confirm the causal relationship
between pollution particle exposure and adverse health effects. Earlier studies enrolled
mostly young healthy subjects and have largely confirmed the capability of particles
to cause adverse health effects shown in epidemiological studies. In the last few
years, more studies involving susceptible populations have been published. These recent
studies in susceptible populations, however, have shown that the adverse responses
to particles appear diminished in these susceptible subjects compared to those in
healthy subjects. The present paper reviewed and compared control human exposure studies
to particles and sought to explain the "unexpected" response to particle exposure
in these susceptible populations and make recommendations for future studies. We found
that the causes for the discrepant results are likely multifactorial. Factors such
as medications, the disease itself, genetic susceptibility, subject selection bias
that is intrinsic to many controlled exposure studies and nonspecificity of study
endpoints may explain part of the results. Future controlled exposure studies should
select endpoints that are more closely related to the pathogenesis of the disease
and reflect the severity of particle-induced health effects in the specific populations
under investigation. Future studies should also attempt to control for medications
and genetic susceptibility. Using a different study design, such as exposing subjects
to filtered air and ambient levels of particles, and assessing the improvement in
biological endpoints during filtered air exposure, may allow the inclusion of higher
risk patients who are likely the main contributors to the increased particle-induced
health effects in epidemiological studies.
Type
Journal articleSubject
HumansLung Diseases, Obstructive
Myocardial Ischemia
Pulmonary Heart Disease
Air Pollutants
Risk Factors
Atmosphere Exposure Chambers
Air Pollution
Environmental Exposure
Population
Particulate Matter
Controlled Clinical Trials as Topic
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https://hdl.handle.net/10161/22247Published Version (Please cite this version)
10.1186/1476-069x-8-33Publication Info
Huang, Yuh-Chin T; & Ghio, Andrew J (2009). Controlled human exposures to ambient pollutant particles in susceptible populations.
Environmental health : a global access science source, 8(1). pp. 33. 10.1186/1476-069x-8-33. Retrieved from https://hdl.handle.net/10161/22247.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Yuh-Chin Tony Huang
Professor of Medicine
Closed loop ventilation Environmental medicine Oxidative lung injuryCOPDHyperpolarized
129Xe MRI and regional lung function

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