Effects of chronic cannabis smoking on lung health

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

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

Quick facts

• Study type: Observational
• Enrollment: 100 (estimated)
• Ages: 18 Years to 55 Years
• Sex: All
• Sponsor: University of Colorado, Denver (Academic / other)
• Locations: 1 site (Aurora, Colorado)
• Trial ID: NCT02480283 on ClinicalTrials.gov

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.

Who should consider this trial

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.

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

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 performed: 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.

Eligibility 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 this trial is running

Aurora, Colorado

• University of Colorado, Denver — Aurora, Colorado, United States (Recruiting)

Study contacts

• Principal investigator: Ellen L Burnham, MD — University of Colorado, Denver
• Study coordinator: Jeffrey D McKeehan, MSN

Conditions Cannabis Smoking; Oxidative Stress