Testing the effects of wood smoke exposure on young healthy adults

Efficacy of Respiratory Protection Against the Effects of Wood Smoke Exposure in Young Healthy Adults

This study is testing how breathing in wood smoke affects the heart and lungs of healthy young adults.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 50 (estimated)
• Ages: 18 Years to 35 Years
• Sex: All
• Sponsor: University of North Carolina, Chapel Hill (Academic / other)
• Locations: 1 site (Chapel Hill, North Carolina)
• Trial ID: NCT06066749 on ClinicalTrials.gov

What this trial studies

This study aims to evaluate the health effects of wood smoke exposure, specifically focusing on the gaseous fraction of wood smoke and its impact on cardiac, respiratory, and systemic inflammatory responses in healthy young adults. Approximately fifty participants aged 18-35 will undergo two controlled exposure sessions to wood smoke in a specialized chamber, wearing a respirator designed to filter out particulate matter and volatile organic compounds. Each session will last two hours, with follow-up assessments conducted 24 hours post-exposure to monitor health effects. The study seeks to enhance understanding of how wood smoke exposure affects cardiovascular and respiratory health.

Who should consider this trial

Good fit: Ideal candidates for this study are healthy individuals aged 18-35 with a normal body mass index and lung function.

Not a fit: Patients with pre-existing cardiovascular or respiratory conditions may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide insights into the health risks associated with wood smoke exposure and inform protective measures for vulnerable populations.

How similar studies have performed: While studies on air pollution and health effects are common, this specific approach to isolating the gaseous fraction of wood smoke is relatively novel.

Eligibility criteria

Inclusion criteria

1. Age 18-35 years old, healthy individuals (Body Mass Index (BMI, kg/m2) values ≥ 19 and ≤ 34, inclusive).
2. Weight equal to or greater than 110 lbs. (Requirement to complete bronchoscopy procedure)
3. Physical conditioning that allows intermittent, moderate exercise for approximately 60 min during a 2-hour exposure session. The volunteer must be able to complete the exposure exercise regimen at a workload sufficient to induce a minute ventilation rate of approximately 25 L/min/m2 for 15 min without exceeding 80% of projected maximal heart rate.
4. Normal ECG.
5. Normal lung function based on NHANES III reference values: Forced vital capacity (FVC) ≥ 80% of that predicted for age, gender, ethnicity, and height; Forced expiratory volume in one second (FEV1) ≥ 80% of that predicted for age, gender, ethnicity, and height; FEV1/FVC ratio ≥ 70% (absolute value).
6. Oxygen saturation greater than 94% at the time of physical exam.

Exclusion criteria

1. Individuals with the following conditions: a) A history of acute or chronic cardiovascular disease, chronic respiratory disease, cancer, rheumatologic disease, neuromuscular disease, or immunodeficiency state, b) Blood pressure readings ≥ 140 systolic and/or ≥ 90 diastolic, c) Diabetes (previously diagnosed or with hemoglobin A1c level equal to or greater than 6.4%) d) Asthma or a history of asthma, e) Bleeding/clotting disorders.
2. Individuals with a cardiovascular disease risk score greater than 10% using the ACC/AHA ASCVD risk calculator. (Based on the 10-year risk of heart disease or stroke using the Atherosclerotic Cardiovascular Disease algorithm published in 2013 American College of Cardiology/American Heart Association Guideline on the Assessment of Cardiovascular risk.)
3. Individuals who have unspecified illnesses, which in the judgment of the medical staff might increase the risk associated with woodsmoke inhalation will be a basis for exclusion.
4. Individuals who have had recent (within 6 month) abdominal and/or eye surgery, or with any types of hernia, as well as any other contraindications for raised intra-abdominal pressure.
5. Individuals who are currently taking systemic steroids or oral anticoagulants long term.
6. Individuals who are taking prescribed medications such as ß-blocker medications, that may impact the results for the duration of the study. Other medications not specifically mentioned here may be reviewed by the medical staff prior to an individual's inclusion in the study. Use of other medications will be evaluated on a case-by-case basis. There is the potential that an individual's current medication use will preclude them from participating in the study at the current time, but they may be reassessed and potentially rescheduled for participation later based on the judgement of the medical staff.
7. Individuals who are allergic to:

   * Chemical vapors or gases.
   * Tape or electrodes on their skin.
   * Or individuals with active allergies or currently experience allergy related symptoms
8. Individuals who are pregnant, attempting to become pregnant or breastfeeding.
9. Individuals who are currently smoking (including vaping, hookah and e-cigarette) or have smoking history within 1 year of study or have an equal to greater than or a 5-pack year smoking history.
10. Individuals living with a smoker who smokes inside the house.
11. Individuals who are regularly exposed to high levels of vapors, dust, gases, or fumes.
12. Individuals who do not read, speak, or understand English well enough to give informed consent.
13. Individuals that are unable to perform the exercise required for the study.
14. Individuals who are unwilling or unable to stop taking any current dietary supplements or vitamins for the duration of the study.
15. Individuals currently taking Omega-3 supplements (i.e. fish oil, krill oil, algae oil).
16. Individuals currently taking prebiotics, probiotics, or antihistamines.
17. Individuals who have experienced an acute respiratory illness within the last 6 weeks.
18. Individuals who have a facial hair or hair style that will interfere with the CAPR seal based on the study team's assessment.
19. Individuals with allergies to the medications used in the bronchoscopy procedure.
20. Individuals with a naris that is too restrictive to permit the fiberoptic bronchoscope to pass comfortably.
21. Regular use of cromolyn (except for prophylaxis of exercise induced bronchospasm) or any use of leukotriene inhibitors (Montelukast or Zafirlukast) within the past month.
22. Night-time symptoms of cough or wheezing greater than 1x/week.
23. Regular use of aspirin or other nonsteroidal anti-inflammatory drug (which inhibit platelet function).
24. Individuals who are not willing to comply with the following requirements: a) Avoid smoke and fumes for 24 hours before all visits, b) Avoid dusty and smoky places for 48 hours prior to follow-up visit, c) Cannot take anything by mouth after midnight the day of the bronchoscopy, d) Cannot travel by bike or motorcycle for any study visit, e) Cannot travel out of town for 24 hours after bronchoscopy, f) Avoid exposure to unvented household combustion sources (gas stoves, lit fireplaces oil/kerosene heaters) for 48 hours before all visit, g) Cannot take any prescription or over-the-counter medications (excluding birth control) for one-week prior to bronchoscopy, h) Avoid drinking alcohol 24 hours before all visits, i) Avoid strenuous exercise for 24 hours prior to and after all visits, j) Eat a light breakfast and low-fat lunch on the exposure day, k) Refrain from eating pan fried and/or grilled foods 12 hours prior to the exposure days, l) Refrain from consuming caffeine for 12 hours prior to all study visits, m) Refrain from consuming food 2 hours prior to the consenting and follow up sessions, as this may interfere with induced sputum collection, n) Wear a N95 mask during all visits to the HSF. A mask will be provided for you upon check-in to the facility, o) Arrive to the medical station within 15 minutes of their scheduled visit time.

Where this trial is running

Chapel Hill, North Carolina

• U.S. Environmental Protection Agency Human Studies Facility — Chapel Hill, North Carolina, United States (Recruiting)

Study contacts

• Principal investigator: James Samet — Environmental Protection Agency (EPA)
• Study coordinator: Robin Kaminski

Conditions Healthy; Wood Smoke; Respirators; Masking