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Asthma & Exposure to Peaks in Particulate Air Pollution

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT00013728
First Posted: March 30, 2001
Last Update Posted: March 23, 2006
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by:
National Institute of Environmental Health Sciences (NIEHS)
  Purpose
We are testing the following two hypotheses: 1) Peaks in hourly exposures to airborne particulate matter (PM) of outdoor origin will be more closely associated with acute asthmatic responses to particles than 24-hour average exposures in susceptible individuals; 2) Personal exposure to PM, and estimated particle dose to the lungs, will be more closely associated with daily asthma severity than standard outdoor particle concentrations measured as 24-hour averages at governmental monitoring sites.

Condition
Asthma

Study Type: Observational
Study Design: Observational Model: Defined Population
Observational Model: Natural History
Time Perspective: Longitudinal
Time Perspective: Prospective

Resource links provided by NLM:


Further study details as provided by National Institute of Environmental Health Sciences (NIEHS):

Estimated Enrollment: 24
Study Start Date: September 2000
Estimated Study Completion Date: October 2003
Detailed Description:
We are testing the following two hypotheses: 1) Peaks in hourly exposures to airborne particulate matter (PM) of outdoor origin will be more closely associated with acute asthmatic responses to particles than 24-hour average exposures in susceptible individuals; 2) Personal exposure to PM, and estimated particle dose to the lungs, will be more closely associated with daily asthma severity than standard outdoor particle concentrations measured as 24-hour averages at governmental monitoring sites. Toxicological data for asthma exacerbations from particulate matter (PM) suggests that particle deposition in the lower respiratory tract can cause inflammatory and lung function changes suggestive of asthma pathology. There is now a scientific need to explain epidemiological findings of ambient PM effects on asthmatics at mass concentrations below what is expected (from toxicological data) to be harmful. One possibility is that study participants are encountering unmeasured short-term excursions of particle mass levels capable of inducing adverse reactions in the lung, but this effect is only captured somewhat by the regulatory standard of 24-hour averages. Our research in southern California is vital to the current controversy regarding regulatory standards given that a health-based scientific rationale for any specific PM averaging time is not established.
  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   9 Years to 18 Years   (Child, Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria
1) physician-diagnosed asthma, at least a 1 yr. history, including episodic symptoms of wheezing, cough and dyspnea; 2) mild to moderate severity of asthma: i) a history of at least several weeks during the warm seasons (Mar-Oct) during which the subject required regular daily use of prescribed prophylactic asthma medications; & ii) asthma exacerbations at least 2 days/week requiring as-needed bronchodilators during an extended period of 1-2 warm season months; 3) age from 9-18; 4) home, school or work addresses in Alpine, CA area; 5) no history of smoking by the subjects and no person smoking in the subject?s home.
  Contacts and Locations
No Contacts or Locations Provided
  More Information

ClinicalTrials.gov Identifier: NCT00013728     History of Changes
Other Study ID Numbers: 6214-CP-001
First Submitted: March 28, 2001
First Posted: March 30, 2001
Last Update Posted: March 23, 2006
Last Verified: March 2006

Keywords provided by National Institute of Environmental Health Sciences (NIEHS):
asthma
particulate matter

Additional relevant MeSH terms:
Asthma
Bronchial Diseases
Respiratory Tract Diseases
Lung Diseases, Obstructive
Lung Diseases
Respiratory Hypersensitivity
Hypersensitivity, Immediate
Hypersensitivity
Immune System Diseases