Clinical trial NCT01699204: Diesel Exhaust and Mechanism of Asthma
Official title: Effects of Diesel Exhaust on Airways
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Asthma
Keywords: Air pollution
Diesel exhaust
Airway responsiveness
Asthma
Anti-oxidant
Lead sponsor: University of British Columbia
Sponsor class: OTHER
First posted: 2012-10-03
Enrollment: 26
Sex: ALL
Minimum age (years): 19
Maximum age (years): 49
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: PREVENTION

Brief summary: This experiment is designed to test the hypothesis that oxidative stress is responsible for changes in airway responsiveness in humans exposed to diesel exhaust.

Detailed description: The specific aim is to test the hypothesis that diesel exhaust (DE) increases airway reactivity via oxidative stress, particularly in asthmatics. To test this hypothesis, we use a crossover in vivo experimental model in mild asthmatics and normal controls using a state-of-the-art diesel exhaust exposure facility.

Participants took N-acetylcysteine (600 mg) or placebo capsules three times daily for six days. On the final morning of supplementation, participants were exposed for 2 hours to either filtered air or diesel exhaust (300 µg·m-3 of particulate matter smaller than 2.5 microns). Twenty-six non-smokers between 19-49 years were studied under three experimental conditions (filtered air with placebo, diesel exhaust with placebo and diesel exhaust with N-acetylcysteine) using randomized, double-blind, crossover design, with a two week minimum washout between conditions. Methacholine challenge was performed pre-exposure (to determine baseline airway responsiveness) and post-exposure (to determine the effect of exposure).

Eligibility criteria: Inclusion Criteria:

* Between 19-49 years, non smokers, asthmatics, healthy controls

Exclusion Criteria:

* Smokers, pregnant or co-existing medical condition for which diesel exhaust would confer significant risk (i.e. coronary artery disease)

Primary outcomes:
measure: Human airway reactivity
timeFrame: 50 hours
Secondary outcomes:
Other outcomes:
Locations:
city: Vancouver
country: Canada
facility: University of British Columbia
state: British Columbia
Study officials:
affiliation: University of British Columbia
name: Christopher Carlsten, MD MPH
role: PRINCIPAL_INVESTIGATOR
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