Lungs on Fire: Wildfire Smoke, Incident Diseases, Susceptible Populations, and Community Values in Canada
Trial Snapshot
- Phase
- Not Applicable
- Status
- Not yet recruiting
- Enrollment
- 24
- Primary Endpoint
- Effects of PM2.5 exposures and concentration on exhaled nitric oxide.
Study Overview
Brief Summary
Wildfire smoke (WFS) is the leading climate-related risk in Canada and the main source of harmful air pollution. While short-term breathing problems caused by smoke are well known, there is limited knowledge on how repeated exposure contributes to long-term lung disease. This study is a controlled human exposure to varying concentrations of WFS in a safe setting. By comparing the effects of different concentrations, this research will improve understanding of health impacts, identify who may be most vulnerable to exposures, and explore biological changes that could lead to chronic illness.
Detailed Description
PURPOSE: To use responses to controlled human exposures to woodsmoke, as a model of wildfire smoke (WFS), to quantify risk of, and add biological plausibility to, the supposition that WFS-related particulate matter with a diameter of 2.5 micrometers or less (PM2.5) contributes to the development of neurological and chronic lung diseases.
Study Exposure Arms:
Arm A: 3 consecutive days with 2h woodsmoke exposures at 35 µg/m3 of PM2.5 Arm B: 3 consecutive days with 2h woodsmoke exposures at 105 µg/m3 of PM2.5 Arm C: 2 consecutive days of Filtered Air (FA), followed by 1 day with a 2h woodsmoke exposure at 315 µg/m3 of PM2.5
HYPOTHESIS, JUSTIFICATIONS, AND OBJECTIVES Aim 1A: Enhance plausibility for, and quantify risk of, WFS contributions to chronic lung disease.
Hypothesis 1A: The investigators will determine mechanisms that plausibly link WFS exposure to the development of chronic disease, by connecting WFS exposures to lung function decline, asthma, chronic obstructive pulmonary disease (COPD), or lung cancer.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Prevention
- Masking
- Triple (Participant, Investigator, Outcomes Assessor)
Masking Description
Blinding of exposures will be performed by the air pollution exposure laboratory (APEL) engineer. Participant coordination and testing will be conducted by a researcher without knowledge of which study arm a given participant is undergoing. The study investigator will be blinded to which study arm participants are undergoing. All assays will be performed by personnel who do not know the exposure conditions of individual samples.
Eligibility Criteria
- Ages
- 19 Years to 80 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Healthy Adults between the ages of 19 to 80 (12 of each biological sex assigned at birth).
Exclusion Criteria
- •Current smoker (within six months before screening; potential to confound exposure effects).
- •History or current diagnosis of any respiratory conditions (including, but not limited to asthma or chronic obstructive pulmonary disease (COPD), asthma/COPD overlap) or other medical conditions that the study physician determines may impact participant safety.
- •Any comorbidities or other concerns identified by the study physician which may impact study participation.
- •For participants of child-bearing potential: Current pregnancy, or plans to become pregnant during study enrolment.
Arms & Interventions
Arm A) Three repeated exposures to a low air pollution concentration
Three consecutive days with a 2-hour woodsmoke exposure at 35 µg/m3 of PM2.5 each day.
Intervention: Woodsmoke (Lodgepole Pine) exposure (Other)
Arm B) Three repeated exposures to a moderate air pollution concentration
Three consecutive days with a 2-hour woodsmoke exposure at 105 µg/m3 of PM2.5 each day.
Intervention: Woodsmoke (Lodgepole Pine) exposure (Other)
Arm C) Single exposure to a higher air pollution concentration
Two consecutive days of 2-hour filtered air exposures, followed by 1 day with a 2-hour woodsmoke exposure at 315 µg/m3 of PM2.5.
Intervention: Woodsmoke (Lodgepole Pine) exposure (Other)
Arm C) Single exposure to a higher air pollution concentration
Two consecutive days of 2-hour filtered air exposures, followed by 1 day with a 2-hour woodsmoke exposure at 315 µg/m3 of PM2.5.
Intervention: Filtered air exposure (Other)
Outcomes
Primary Outcomes
Effects of PM2.5 exposures and concentration on exhaled nitric oxide.
Time Frame: Comparison of the different arms over the span of 4 months.
Measurement of fractional exhaled nitric oxide (FeNO).
Effects of PM2.5 exposures and concentration on Cambridge Neuropsychological Test Automated Battery (CANTAB)
Time Frame: Comparison of the different arms over the span of 4 months.
Computational testing using CANTAB to determine e.g. 5-choice reaction time and percent correct all delays.
Secondary Outcomes
- Effects of PM2.5 exposures and concentration on sputum cell numbers.(Comparison of the different arms over the span of 4 months.)
- Effects of PM2.5 exposures and concentration on brain functional connectivity.(Comparison of the different arms over the span of 4 months.)
- Effects of PM2.5 exposures and concentration on oxidative stress.(Comparison of the different arms over the span of 4 months.)
- Effects of PM2.5 exposures and concentration on lung inflammatory markers.(Comparison of the different arms over the span of 4 months.)
- Effects of PM2.5 exposures and concentration on lung imaging.(Comparison of the different arms over the span of 4 months.)
- Effects of PM2.5 exposures and concentration on circulating brain-derived biomarkers of neuroinflammation.(Comparison of the different arms over the span of 4 months.)
- Effects of PM2.5 exposures and concentration on neutrophil extracellular traps (NETs).(Comparison of the different arms over the span of 4 months.)
- Effects of PM2.5 exposures and concentration on host defence proteins.(Comparison of the different arms over the span of 4 months.)
- Effects of PM2.5 exposures and concentration on DNA methylation.(Comparison of the different arms over the span of 4 months.)
- Effects of PM2.5 exposures and concentration on glia-derived extracellular vesicles.(Comparison of the different arms over the span of 4 months.)
Investigators
Christopher Carlsten
Professor
University of British Columbia