Children's Exposures/Health Effects/Diesel Exhaust

Completed

Conditions studied: Asthma, Airway Inflammation

In brief

The contribution of diesel exhaust (DE) to health, especially children's health, is of tremendous public health interest. DE has been associated with worsening asthma and allergies, among other important health effects. Reducing DE exposures has become a major regulatory initiative, and federal, state, and local jurisdictions are investing hundreds of millions of dollars in retrofitting diesel engines in school buses and other changes to reach this goal. The U.S. Environmental Protection Agency's recent regulations require all on-road diesel vehicles to change to low emission engines and ultra-low-sulfur fuels by 2007 (US EPA '00). In spring 2003, the U.S. EPA announced a nationwide voluntary school bus retrofit initiative. In July 2003, the Washington Legislature enacted a statewide "Diesel Solutions" program that provides 25 million dollars by 2008 to retrofit school diesel buses with cleaner burning engines and fuels, making it one of the largest and most active voluntary school bus retrofit program in the country. If risk assessment estimates are accurate, these changes will have a large public health impact, especially on children who ride school buses daily. However, no studies to-date have rigorously examined school children's exposure to diesel exhaust (DE) and its health effects, nor such a significant change in vehicular pollution control. We propose to seize this opportunity of a large natural experiment taking place in the Puget Sound area and conduct a study to assess health effects from diesel bus exhaust before and after the retrofit of diesel bus fleets between 2005 and 2007. The specific aims of the study are to: 1. Determine whether asthmatic children changing to retrofitted buses with cleaner fuels and engines have a reduction in sub-clinical and clinical asthma severity. 2. Determine if increased levels of DE exposure lead to an increase in acute clinical and sub-clinical features of asthma in children. 3. Quantify the levels and changes in particle and toxic gas exposures to DE in 3 groups of children commuting to school by retrofitted buses or private cars, old diesel buses to be retrofitted later, and old diesel buses through the study. Sub-aim 3: Use the time-activity information, personal exposure measurements, and on-bus monitoring data to construct an exposure model to predict individual exposures to DE for all subjects.

Key facts

Study ID

NCT00527345

Run by

National Institute of Environmental Health Sciences (NIEHS)

People needed

450

Starts

2005-03-01

Expected to finish

2009-07-01

Last updated by the study team

2015-04-14

Who can join

Age: 6 and older, up to 11. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• ages 6-11 and attending 1st to 5th grades at schools in one of our target districts; approximately 75% subjects will commute by bus daily, 25% commute by car/walking;
• with or without physician-diagnosed asthma
• If with physician-diagnosed asthma:
• 1 year history, including episodic symptoms of wheezing, cough, and dyspnea;
• mild intermittent (with at least one episode a week requiring inhaler), mild persistent, or moderate persistent severity of asthma by NAEPP Criteria (NHLBI '91);

You may not qualify if…

• history of smoking by the subject or by a person in the subject's home
• asthma hospitalizations within 4 weeks of the start of each study year
• other chronic diseases such as diabetes, congenital heart disease, chronic renal disease
• new pets in the home

Where it is running

• University of Washington Dept. Environmental and Occupational Health Sciences — Seattle, Washington, United States

Full record on ClinicalTrials.gov

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