Clinical trial Recruiting at 1 site Observational Ages 18 to 55

Effects of chronic cannabis smoking on lung health

Official title: Chronic Cannabis Smoking, Oxidative Stress and the Pulmonary Innate Immune Response

Run by University of Colorado, Denver · NCT02480283 · Data updated 2026-11-12

This study is trying to see how long-term cannabis smoking affects lung health in regular users compared to non-smokers.

More Oxidative Stress trials

Quick facts

Study typeObservational
Ages18 Years to 55 Years
SexAll
Enrollment100 (estimated)
SponsorUniversity of Colorado, Denver
Academic / other
Locations1 site (Aurora, Colorado)
StatusRecruiting
StartedNovember 11, 2015
Main results expectedJuly 2026
Study endsJuly 2027
Registry record updatedOctober 10, 2024
Trial IDNCT02480283 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates include individuals who smoke cannabis daily or nearly daily with significant exposure, while controls are non-users of cannabis and tobacco.

Probably not a fit

Patients who have never smoked cannabis or have a significant history of tobacco use may not benefit from this study.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This observational study aims to evaluate the impact of chronic cannabis smoking on pulmonary health, specifically focusing on lung physiology and the function of alveolar macrophages. The research is motivated by the increasing prevalence of cannabis use and the unclear effects it has on lung health, particularly in light of higher THC concentrations in today's cannabis compared to the past. The study will involve various interventions, including bronchoscopy and chest X-rays, to assess oxidative stress and immune response in habitual cannabis smokers compared to non-users. The findings could provide valuable insights into the respiratory consequences of cannabis smoking.

Why it matters

Potential benefit: If successful, this study could enhance understanding of the respiratory effects of cannabis smoking and inform public health guidelines.

How similar studies have gone: While there is limited data on the effects of chronic cannabis smoking in humans, previous animal studies have indicated potential risks, making this a novel investigation.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria:

INCLUSION CRITERIA for CANNABIS USING patient: Subjects will be eligible if they meet ALL of the following criteria:

1. Daily or near daily cannabis use (inhaled via joint/cigarette or pipe) equivalent to AT LEAST 20 "joint years" (number of joints/cigarettes per day multiplied by number of years during which cannabis was smoked) by self-report and validated through urine drug screen.
2. Never or limited exposure to inhaled tobacco products (equivalent to LESS THAN one "pack year" in a lifetime) by selfreport and validated through negative urine cotinine screen.
3. Capacity to answer screening questions and provide informed consent at time of interview, along with contact information

INCLUSION CRITERIA for CONTROL patient: Subjects will be eligible if they meet all of the following:

1. No cannabis use ever by self-report, and validated through urine drug screen.
2. Never users of tobacco/cigarettes
3. Capacity to answer screening questions and provide informed consent at time of interview, along with contact information.

Exclusion Criteria:

EXCLUSION CRITERIA for CANNABIS USING patient: Subjects will be ineligible if they meet ANY of the following criteria:

1. LESS THAN near daily cannabis use (inhaled via joint/cigarette or pipe) equivalent to LESS THAN 20 "joint years" (number of joints/cigarettes per day multiplied by number of years during which cannabis was smoked) or a negative urine drug screen (for cannabis)
2. Inhaled tobacco product exposure EXCEEDING one "pack year" or a positive urine cotinine screen
3. Elevated AUDIT-C score: A 3 item questionnaire to identify subjects with alcohol use disorders.
4. Prior medical history of liver disease: cirrhosis, total bilirubin \> 2.0 mg/dL or albumin \<3
5. Prior medical history of myocardial infarction or congestive heart failure
6. Prior medical history of end-stage renal disease or serum creatinine \>3 mg/dL
7. Prior history of or current use of illicit drug use defined as a positive toxicology screen for opiates or cocaine
8. Prior history of diabetes mellitus
9. Prior history of chronic obstructive pulmonary disease (COPD) or asthma that is not clinically controlled (have not required systemic corticosteroids in the past month)
10. Prior history of HIV, not controlled or on medication
11. Peripheral white blood cell count of less than 3000
12. Acute worsening (\<7 days) in respiratory symptoms (such as change in cough frequency or sputum production, fever, dyspnea, abnormal chest radiograph), or room air pulse oximetry of \< 92% at rest or spirometry of \< 50% predicted for FEV1 and FVC
13. Use of systemic antibiotics for any reason in the past month (4 weeks)
14. Failure of a subject or the subject's substance abuse counselor to provide assent
15. Nutritional risk index of less than 95
16. Age \< 21 or \> 55 (using an age of 55 limits the likelihood of comorbid conditions that may increase the risk of adverse events with bronchoscopy)
17. Pregnancy
18. Decisionally challenged
19. Prisoners.

EXCLUSION CRITERIA for CONTROL patient: Subjects will be ineligible to participate if they meet ANY of the following criteria:

1. History of inhaled cannabis exposure EXCEEDING one "joint year" or positive urine toxicology screen (for cannabis)
2. History of inhaled tobacco product exposure EXCEEDING one "pack year" or a positive urine cotinine screen
3. Elevated AUDIT-C score: A 3 item questionnaire to identify subjects with alcohol use disorders.
4. Prior medical history of liver disease: cirrhosis, total bilirubin \> 2.0 mg/dL or albumin \<3
5. Prior medical history of myocardial infarction or congestive heart failure
6. Prior medical history of end-stage renal disease or serum creatinine \>3 mg/dL
7. Prior history of or current use of illicit drug use defined as a positive toxicology screen for opiates or cocaine
8. Prior history of diabetes mellitus
9. Prior history of chronic obstructive pulmonary disease (COPD) or asthma that is not clinically controlled (have not required systemic corticosteroids in the past month)
10. Prior history of HIV, not controlled or on medication
11. Peripheral white blood cell count of less than 3000
12. Acute worsening (\<7 days) in respiratory symptoms (such as change in cough frequency or sputum production, fever, dyspnea, abnormal chest radiograph), or room air pulse oximetry of \< 92% at rest or spirometry of \< 50% predicted for FEV1 and FVC
13. Use of systemic antibiotics in the past month (4 weeks)
14. Failure of a subject or the subject's substance abuse counselor to provide assent
15. Nutritional risk index of less than 95
16. Age \< 21 or \> 55
17. Pregnancy
18. Decisionally challenged
19. Prisoners.

Where it's running

  • University of Colorado, Denver
    Aurora, Colorado, United States
    Recruiting

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

  • Diabetes, Dementia, and Oxidative Stress: A look at Nox2-related markers

    This study tests whether oxidative stress linked to Nox2 is related to dementia risk in adults with type 2 diabetes.

    Recruiting Neuromed IRCCS · Pozzilli · NCT07928453

  • Opioid-Free vs Opioid-Based Anesthesia for Thyroid Surgery

    This study tests whether a non-opioid anesthesia approach can match or improve outcomes for adults undergoing thyroidectomy.

    Recruiting Malatya Egitim Ve Arastirma Hastanesi · Malatya · NCT07864155

  • Training to reduce oxidative stress in knee OA

    A six-week program compares supervised knee-strengthening training with a daily 6,000-step walking plan to see if it improves pain, function, and blood markers of cellular stress in people with knee osteoarthritis.

    Recruiting Vrije Universiteit Brussel · Capelle aan den IJssel · NCT07845838

  • Ashwagandha with resistance training to boost strength and stress markers

    This 12-week study tests whether taking ASHWAGANDHA along with regular resistance training helps healthy, trained men see improvements in strength, stress levels, sleep, and cognitive function compared with a placebo.

    Recruiting Gdansk University of Physical Education and Sport · Gdansk, Pomeranian Voivodeship · NCT07803068

  • Oxidative Stress and Heart Risk in People with Rheumatoid Arthritis

    This study tests whether certain markers of oxidative stress in people with rheumatoid arthritis are linked to subclinical atherosclerosis and arterial stiffness, which could relate to future heart disease risk.

    Recruiting University of La Laguna · Santa Cruz de Tenerife, Canary Islands · NCT07760662

  • NVTIA Ergothioneine for Healthy Aging and Skin Health

    This study tests whether taking NVTIA Ergothioneine daily for 12 weeks helps healthy adults age more gracefully and keeps skin looking and feeling better compared with a placebo.

    Recruiting European Life Science Research Association · Dhaka · NCT07750002

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.