NCT03909477

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.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
200

participants targeted

Target at P75+ for all trials

Timeline
56mo left

Started Jun 2022

Longer than P75 for all trials

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress46%
Jun 2022Dec 2030

First Submitted

Initial submission to the registry

March 25, 2019

Completed
16 days until next milestone

First Posted

Study publicly available on registry

April 10, 2019

Completed
3.1 years until next milestone

Study Start

First participant enrolled

June 1, 2022

Completed
8.5 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

December 1, 2030

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

December 1, 2030

Last Updated

August 15, 2025

Status Verified

August 1, 2025

Enrollment Period

8.5 years

First QC Date

March 25, 2019

Last Update Submit

August 11, 2025

Conditions

Outcome Measures

Primary Outcomes (9)

  • Changes in airways over time

    Measured using Xenon-129 (129-Xe) MRI

    3 years

  • Changes in parenchyma over time

    Measured using Xenon-129 (129-Xe) MRI

    3 years

  • Differences in lung ventilation in cannabis smokers compared to never-smokers and tobacco smokers

    Measured using 129-Xe MRI

    3 years

  • Differences in perfusion in cannabis smokers compared to never-smokers and tobacco smokers

    Measured using 129-Xe MRI

    3 years

  • Differences in parenchyma integrity in cannabis smokers compared to never-smokers and tobacco smokers

    Measured using 129-Xe MRI

    3 years

  • Differences in airways between cannabis-only smokers and cannabis and tobacco smokers

    Measured using 129-Xe MRI

    3 years

  • Differences in parenchyma between cannabis-only smokers and cannabis and tobacco smokers

    Measured using 129-Xe MRI

    3 years

  • Dose-response of cannabis use to changes in airways over time

    Measured using 129-Xe MRI

    3 years

  • Dose-response of cannabis use to changes in parenchyma over time

    Measured using 129-Xe MRI

    3 years

Study Arms (1)

Cannabis Smoker

Participants in this group will be current or former cannabis smokers

Diagnostic Test: Hyperpolarized Xenon-129 MRI of the lungsDiagnostic Test: Computed Tomography (CT)Diagnostic Test: Pulmonary Function Tests (PFTs)Diagnostic Test: Six Minute Walk Test (6MWT)Diagnostic Test: Cardiopulmonary exercise testing (CPET)Diagnostic Test: Sputum analysisDiagnostic Test: Blood analysis

Interventions

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

Cannabis Smoker

Participants will undergo a CT scan of the thoracic cavity

Also known as: CT
Cannabis Smoker

Participants will have their lung function evaluated using PFTs

Also known as: PFTs
Cannabis Smoker

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

Also known as: 6MWT
Cannabis Smoker

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

Also known as: CPET
Cannabis Smoker
Sputum analysisDIAGNOSTIC_TEST

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

Cannabis Smoker
Blood analysisDIAGNOSTIC_TEST

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

Cannabis Smoker

Eligibility Criteria

Age18 Years - 85 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)
Sampling MethodProbability Sample
Study Population

Current and former smokers of cannabis

You may qualify if:

  • 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

You may not qualify if:

  • 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.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

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

London, Ontario, N6A 5B7, Canada

RECRUITING

MeSH Terms

Conditions

Marijuana Smoking

Interventions

Tomography, X-Ray ComputedRespiratory Function TestsWalk TestExercise TestHematologic Tests

Condition Hierarchy (Ancestors)

Marijuana UseBehaviorSmoking, Non-Tobacco ProductsSmoking

Intervention Hierarchy (Ancestors)

Image Interpretation, Computer-AssistedDiagnostic ImagingDiagnostic Techniques and ProceduresDiagnosisRadiographic Image EnhancementImage EnhancementPhotographyRadiographyTomography, X-RayTomographyDiagnostic Techniques, Respiratory SystemHeart Function TestsDiagnostic Techniques, CardiovascularErgometryInvestigative TechniquesClinical Laboratory Techniques

Study Officials

  • Grace E Parraga, PhD

    Robarts Research Institute, The University of Western Ontario

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Grace E Parraga, PhD

CONTACT

Angela P Wilson, RRT

CONTACT

Study Design

Study Type
observational
Observational Model
COHORT
Time Perspective
PROSPECTIVE
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

March 25, 2019

First Posted

April 10, 2019

Study Start

June 1, 2022

Primary Completion (Estimated)

December 1, 2030

Study Completion (Estimated)

December 1, 2030

Last Updated

August 15, 2025

Record last verified: 2025-08

Locations