Clinical trial NCT06749093: Health Effects of Wood Smoke and Traffic-Related Air Pollution Exposures: a Necessary Comparison
Official title: Health Effects of Wood Smoke and Traffic-Related Air Pollution Exposures: a Necessary Comparison
Study type: INTERVENTIONAL
Overall status: NOT_YET_RECRUITING
Phase: NA
Conditions: Healthy Individuals
Allergic Rhinitis
Keywords: Air Pollution
Wood Smoke
Diesel Exhaust
Lead sponsor: University of British Columbia
Sponsor class: OTHER
First posted: 2024-12-27
Enrollment: 48
Sex: ALL
Minimum age (years): 19
Maximum age (years): 40
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief summary: Accumulating evidence demonstrates that breathing air pollutants leads to devastating increases in sickness and death worldwide over time. However, there is little data comparing the effects of different types of air pollution on health. In Canada, traffic-related air pollution and wood smoke (wildfires and wood burning for heating) are very common air pollutants. This study aims to safely complete a controlled human exposure study to test how these air pollution types acutely affect health.

Detailed description: Healthy adult participants (total 48; 24 of each biological sex assigned at birth) will breathe filtered air (control), wood smoke (WS), diesel exhaust (DE), and DE plus WS (DEWS) each for 2 hours, with 4 weeks between each exposure (washout). Before and after each exposure, participants will answer questions, perform breathing tests, and give blood samples. At 24 hours after each exposure, participants will undergo a bronchoscopy to collect samples from their lungs.

The study will look at what (if any) are the differences between breathing in fresh air (filtered air - FA) or polluted air containing either wood smoke (WS), diesel exhaust (DE) or diesel exhaust plus wood smoke (DEWS). The research team will use wood smoke generated from pine wood, since it is one of the most common types of wood found in Western Canadian forests where forest fires occur.

The investigators will evaluate multiple endpoints as detailed in the Outcome Measures section. For each applicable endpoint, the investigators will evaluate stratified analyses and effect modification by biological sex, participant age, gene score, and microbiomes.

Eligibility criteria: Inclusion Criteria:

* Age 19-40
* Healthy, with no history of respiratory disease
* Lifetime non-smoker and non-vaper.

Exclusion Criteria:

* Pregnant, planning to become pregnant, or breastfeeding during the study period (confirmed through pregnancy tests at each visit if applicable)
* Frequent WS or DE exposures (e.g. home fireplace used for heating/cooking, or employment in transportation, mining, or as a firefighter).

Primary outcomes:
measure: Woodsmoke (WS) and/or diesel exhaust (DE) exposure effects on inflammatory cells in the lungs.
timeFrame: Comparison of the different arms (over the span of ~5 months).
measure: Within-individual change in lung transcriptomic biomarkers of inflammation following exposure to woodsmoke and/or diesel exhaust.
timeFrame: Through study completion, anticipated ~5 months.
measure: Within-individual change in lung protein biomarkers of inflammation following exposure to woodsmoke and/or diesel exhaust.
timeFrame: Through study completion, anticipated ~5 months.
measure: Within-individual change in circulating transcriptomic biomarkers of inflammation following exposure to woodsmoke and/or diesel exhaust.
timeFrame: Through study completion, anticipated ~5 months.
measure: Within-individual change in circulating protein biomarkers of inflammation following exposure to woodsmoke and/or diesel exhaust.
timeFrame: Through study completion, anticipated ~5 months.
measure: Within-individual change in airway resistance following exposures to woodsmoke and/or diesel exhaust.
timeFrame: Through study completion, anticipated ~5 months.
Secondary outcomes:
measure: Woodsmoke (WS) and/or diesel exhaust (DE) exposure effects on inflammatory cells in the nose.
timeFrame: Comparison of the different arms (over the span of ~5 months).
measure: Within-individual changes in exhaled nitric oxide following woodsmoke (WS) and/or diesel exhaust (DE) exposures.
timeFrame: Comparison of the different arms (over the span of ~5 months).
measure: Woodsmoke (WS) and/or diesel exhaust (DE) exposure effects on symptoms, stress and perceptions.
timeFrame: Comparison of the different arms (over the span of ~5 months).
measure: Woodsmoke (WS) and/or diesel exhaust (DE) exposure effects on lung function.
timeFrame: Comparison of the different arms (over the span of ~5 months).
measure: Woodsmoke (WS) and/or diesel exhaust (DE) exposure effects on nasal resistance.
timeFrame: Comparison of the different arms (over the span of ~5 months).
Other outcomes:
Locations:
city: Vancouver
country: Canada
facility: University of British Columbia
state: British Columbia
Study officials:
affiliation: University of British Columbia
name: Chris Carlsten, MD
role: PRINCIPAL_INVESTIGATOR
References: