Recruiting

Observational Study

Sponsor:

Western University, Canada

Code:

NCT03909477

Conditions

Cannabis Use

Cannabis Smoking

Marijuana Smoking

Marijuana Usage

Eligibility Criteria

Sex: All

Age: 18 - 70+

Healthy Volunteers: Accepted

Interventions

Hyperpolarized Xenon-129 MRI of the lungs

Computed Tomography (CT)

Pulmonary Function Tests (PFTs)

Six Minute Walk Test (6MWT)

Cardiopulmonary exercise testing (CPET)

Study Details

Brief summary:

This is a longitudinal study of the long-term health impact of cannabis smoking on the lungs. Participants will be followed over a period of 3 years, and impacts of cannabis smoking on the lungs will be measured with magnetic resonance imaging (MRI) using hyperpolarized xenon-129 gas, pulmonary function tests, exercise capacity, computed tomography images and questionnaires.

Conditions

Cannabis Use

Cannabis Smoking

Marijuana Smoking

Marijuana Usage

Study ID

NCT03909477

Start date

Jun 1, 2022

Status verified date

Aug, 2025

Completion date

Dec 1, 2030

Anticipated

Primary completion date

Dec 1, 2030

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 70+

Healthy Volunteers: Accepted

Inclusion Criteria:

  • Patient understands study procedures and is willing to participate in the study as indicated by the patient's signature
  • Provision of written, informed consent prior to any study specific procedures
  • Males and females aged 18-85
  • Current or former cannabis smoker (medicinal or recreational) with or without concurrent tobacco smoking history
  • Participant is able to perform reproducible pulmonary function testing (i.e. the 3 best acceptable spirograms have Forced Expiratory Volume in 1 second (FEV1) values that do not vary more than 150 millilitres)
  • Participant is able to perform a breathhold for 16s
  • FEV1 > 25% predicted
  • Forced Vital Capacity (FVC) > 25% predicted and >0.5 litres

Exclusion Criteria:

  • Participant is, in the opinion of the investigator, mentally or legally incapacitated, preventing informed consent from being obtained, or cannot read or understand written material
  • Participant is medically unstable in the opinion of the Principal Investigator
  • Participant has a daytime room air oxygen saturation <90% while lying supine
  • Participant is unable to perform spirometry or plethysmography maneuvers
  • Patient is pregnant at time of enrolment
  • In the opinion of the investigator, patient suffers from any physical, psychological or other condition(s) that might prevent performance of the MRI, such as severe claustrophobia
  • Patient has implanted mechanically, electrically or magnetically activated device or any metal in their body, which cannot be removed, including but not limited to pacemakers, neurostimulators, biostimulators, implanted insulin pumps, aneurysm clips, bioprosthesis, artificial limb, metallic fragment or foreign body, shunt, surgical staples (including clips or metallic sutures and/or ear implants) - at the discretion of the MRI Technologist.

Study Design

Enrollment

200 participants

Anticipated

Interventions and Outcome Measures

Arms

Cannabis Smoker

Participants in this group will be current or former cannabis smokers

Interventions

Hyperpolarized Xenon-129 MRI of the lungs

Participants will be imaged using MRI using hyperpolarized xenon-129 gas as a contrast gas

Computed Tomography (CT)

Participants will undergo a CT scan of the thoracic cavity

Pulmonary Function Tests (PFTs)

Participants will have their lung function evaluated using PFTs

Six Minute Walk Test (6MWT)

Participants >35 years of age will perform the six minute walk test as a measure of exercise capacity

Cardiopulmonary exercise testing (CPET)

Participants <35 will perform cardiopulmonary exercise testing as a measure of exercise capacity

Sputum analysis

Participants will provide a sputum sample that will be analysed for eosinophils

Blood analysis

Participants will have their blood drawn and analysed for eosinophil count.

Primary outcome measure

  • Changes in airways over time [ Time Frame: 3 years ]
  • Changes in parenchyma over time [ Time Frame: 3 years ]
  • Differences in lung ventilation in cannabis smokers compared to never-smokers and tobacco smokers [ Time Frame: 3 years ]
  • Differences in perfusion in cannabis smokers compared to never-smokers and tobacco smokers [ Time Frame: 3 years ]
  • Differences in parenchyma integrity in cannabis smokers compared to never-smokers and tobacco smokers [ Time Frame: 3 years ]
  • Differences in airways between cannabis-only smokers and cannabis and tobacco smokers [ Time Frame: 3 years ]
  • Differences in parenchyma between cannabis-only smokers and cannabis and tobacco smokers [ Time Frame: 3 years ]
  • Dose-response of cannabis use to changes in airways over time [ Time Frame: 3 years ]
  • Dose-response of cannabis use to changes in parenchyma over time [ Time Frame: 3 years ]

Central Contacts and Locations

Central contacts

Grace E Parraga, PhD

519-931-5265gparraga@uwo.ca

Angela P Wilson, RRT

519-931-5777awilson@robarts.ca

Locations

Robarts Research Institute; The University of Western Ontario; London Health Sciences Centre

Recruiting

London, Ontario, Canada, N6A 5B7

Contacts

Grace E Parraga, PhD

519-931-5265gparraga@uwo.ca

More Information

Sponsor

Western University, Canada

Last update posted

Aug 15, 2025

Last verified

Aug, 2025

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Western University, Canada on 2025-08-15.