Effects of wood smoke on heart health in young adults

Cardiovascular Effects of Exposure to Wood Smoke in Healthy Human Adults

This study tests how breathing in wood smoke affects heart and lung health in healthy young adults aged 18-35.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 80 (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: NCT04297761 on ClinicalTrials.gov

What this trial studies

This study investigates the cardiovascular effects of wood smoke exposure in healthy young adults aged 18-35. Participants will undergo two exposure sessions, one with filtered air and another with wood smoke, each lasting two hours and including periods of exercise. Measurements of lung, cardiac, and vascular function, along with blood and sputum samples, will be collected before and after each exposure. The goal is to enhance understanding of how wood smoke impacts cardiovascular and respiratory health.

Who should consider this trial

Good fit: Ideal candidates are healthy young adults aged 18-35 with a BMI between 19 and 34 who can perform mild exercise.

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, potentially informing public health guidelines.

How similar studies have performed: While studies on air pollution effects exist, this specific investigation into wood smoke exposure in healthy young adults is relatively novel.

Eligibility criteria

Inclusion criteria:

1. Age 18-35 years old , healthy, with a Body Mass Index (BMI, kg/m\^2) values ≥ 19 and ≤ 34, inclusive).
2. Physical conditioning that allows intermittent, mild 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 20 L/min/m\^2 for 15 min without exceeding 80% of projected maximal heart rate.
3. Normal ECG.
4. Normal lung function based on NHANES III reference values. i. Forced vital capacity (FVC) ≥ 80% of that predicted for age, gender, ethnicity, and height.

   ii. Forced expiratory volume in one second (FEV1) ≥ 80% of that predicted for age, gender, ethnicity, and height.

   iii: FEV1/FVC ratio ≥ 70% (absolute value)
5. Oxygen saturation greater than 94% at the time of physical exam.

Exclusion criteria:

1. Individuals with the following conditions:

   * A history of acute or chronic cardiovascular disease, chronic respiratory disease, cancer, rheumatologic disease, neuromuscular disease, or immunodeficiency state.
   * BMI (kg/m\^2) values \< 19 and \> 34.
   * Blood pressure readings ≥ 140 systolic and/or ≥ 90 diastolic.
   * Diabetes (previously diagnosed or with hemoglobin A1c level equal to or greater than 6.4%).
   * Asthma or a history of asthma.
   * 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 wood smoke inhalation will be a basis for exclusion.
4. Individuals who have had recent (within 6 months) abdominal an/or eye surgery, or with any types of hernia, as well as any other contraindicators 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 of wood smoke challenge 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 prebiotics, probiotics, or antihistamines.
16. Individuals who have experienced an acute respiratory illness within the last 6 weeks.
17. Individuals that will NOT comply with the following requirements:

    * Avoid smoke and fumes for 24 hours before all visits.
    * Avoid exposure to unvented household combustion sources (gas stoves, lit fireplaces, oil/kerosene heaters) for 48 hours before all visits.
    * Avoid over-the-counter pain medications such as aspirin, Advil, Aleve, or NSAIDs for 48 hours before all visits.
    * Avoid drinking alcohol 34 hours before all visits
    * Avoid strenuous exercise for 24 hours prior to an after all visits.
    * Eat a light breakfast and low-fat lunch on the exposure day.
    * Refrain from eating pan fried and/or grilled foods 12 hours prior to the exposure days.
    * Refrain from consuming caffeine for 12 hours prior to all study visits.
    * Refrain from consuming food 2 hours prior to the consenting and follow up sessions, as this may interfere with induced sputum collection.
    * Wear a N95 mask during all visits to the HSF. A mask will be provided to participants upon check-in.

Since examining changes of cells in the induced sputum is an important test for this study, if a subject is a non-producer, or if the quality of their sputum sample does not meet the requirements, they will be disqualified and imbursed for participation up to this point.

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, PhD — Environmental Protection Agency (EPA)
• Study coordinator: Robin Kaminski

Conditions Healthy; Healthy subjects; Wood smoke; Respiratory effects; Cardiovascular effects; Young