The Canadian Lung Outcomes in Users of Vaping Devices Study (CLOUD)

March 24, 2026 updated by: Janice Leung, University of British Columbia

The Canadian Lung Outcomes in Users of Vaping Devices (CLOUD) Study

Vaping is increasingly popular with both adolescent and adult Canadians, but the long-term health impacts remain unknown. We believe that the tools we currently have to detect lung disease in people who vape may be insufficient and propose new ways to find lung injuries that may impact them over the course of their lives. These include exercise testing, new imaging techniques, and new breathing tests that will demonstrate how vaping may harm their lungs. We will use these tools in both adolescent and adult Canadians to give Canadians who vape important information on the consequences of vaping.

Study Overview

Status

Recruiting

Conditions

Detailed Description

Promoted as a safer method of inhaling nicotine compared to cigarettes and as smoking cessation tools, e-cigarettes have substantially grown in popularity with rates of uptake now exceeding those of cigarette smoking. In Canada, 6% of Canadians aged 15 years and older have vaped in the past 30 days. Younger Canadians appear to be the most susceptible to these habits, with 14% of those aged 15-19 years and 18% of those aged 20-24 years reporting past 30 day use. Indigenous populations are also disproportionately affected by the spread of vaping which may place them at higher risk for potential downstream respiratory complications. As Canadians increasingly reach for e-cigarettes, especially at younger ages and not just for the purposes of smoking cessation, greater clarity into the pulmonary toxicities vaping is urgently needed.

The Canadian Lung Outcomes in Users of Vaping Devices (CLOUD) Study is a pan-Canadian, multicentre, multidisciplinary, and longitudinal approach to studying vaping from cell to society. The characterization of e-cigarettes' respiratory effects remains superficial and a more comprehensive phenotyping of vaping-exposed lungs across the lifespan using novel imaging and pulmonary function techniques, dynamic exercise testing, and airway cell sequencing would significantly enhance our understanding of the potential harms. As with combustible cigarette smoking, the small airways (characterized by a diameter <2mm) may be particularly vulnerable during vaping given their high degree of exposure to particulate matter. These regions of the lung may harbour the earliest signs of injury, ultimately setting the stage for future obstructive airways disease.

Objectives

The objective of the CLOUD Study is to characterize small airway injury in adolescent and adult Canadians who use e-cigarettes. Specifically, our goals are to:

  1. Characterize the structural and functional disruptions associated with e-cigarette use using oscillometry, multiple breath washout, chest computed tomography, hyperpolarized 129-xenon magnetic resonance imaging, cardiopulmonary exercise testing, and bronchoscopy.
  2. Determine the association between e-cigarette use and respiratory outcomes, including symptom burdens, exacerbation-like respiratory events, and school and work absences.
  3. Characterize the epigenetic and transcriptomic disruptions associated with e-cigarette use in blood, sputum, airway epithelium, and lung immune cells.

Methods Our observational, longitudinal cohort study encompasses six academic hospital centres across Canada (the University of British Columbia, the University of Alberta, McMaster University, the University of Ottawa, the University of Toronto, and the Université de Sherbrooke). Participants (n=100 ages >12 and <19 years and n=400 ages ≥19 years) will be followed over 3 years, undergoing repeat demographic and respiratory symptom questionnaires, oscillometry, pulmonary function testing, and exercise testing. Adolescent participants will additionally undergo multiple breath washout and induced sputum collection and adult participants will undergo chest CT imaging and bronchoscopy. A substudy of adolescent and adult participants undergoing pulmonary hyperpolarized 129-xenon gas magnetic resonance imaging will also be performed. Induced sputum and bronchoscopy-derived airway epithelial and bronchoalveolar lavage samples will be sequenced for methylation and transcriptomics.

Study Type

Observational

Enrollment (Estimated)

500

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Canada
    • Alberta
      • Edmonton, Alberta, Canada, T6G 2B7
        • Recruiting
        • University of Alberta (Clinical Sciences Building)
        • Contact:
        • Contact:
        • Sub-Investigator:
          • Michael Stickland
        • Sub-Investigator:
          • Joanna Maclean
    • British Columbia
      • Vancouver, British Columbia, Canada, V6Z 1Y6
        • Recruiting
        • St. Paul's Hospital
        • Contact:
        • Contact:
        • Principal Investigator:
          • Janice Leung
        • Sub-Investigator:
          • Don Sin
        • Sub-Investigator:
          • Rachel Eddy
        • Sub-Investigator:
          • Jonathon Leipsic
      • Vancouver, British Columbia, Canada, V5Z 4E6
      • Vancouver, British Columbia, Canada, V6H 3N1
    • Ontario
      • Hamilton, Ontario, Canada, L8N 4A6
        • Not yet recruiting
        • McMaster University (Research Institute of St. Joe's Hamilton)
        • Contact:
        • Contact:
        • Sub-Investigator:
          • Terence Ho
        • Sub-Investigator:
          • Sarah Svenningsen
      • Ottawa, Ontario, Canada, K1H 8L6
        • Recruiting
        • University of Ottawa (The Ottawa Hospital General Campus)
        • Contact:
        • Contact:
        • Sub-Investigator:
          • Shawn Aaron
      • Toronto, Ontario, Canada, M5G 1E8
        • Not yet recruiting
        • University of Toronto (The Hospital for Sick Children)
        • Contact:
        • Contact:
        • Sub-Investigator:
          • Trisha Tulloch
        • Sub-Investigator:
          • Brandon Zanette
        • Sub-Investigator:
          • Theo Moraes
        • Sub-Investigator:
          • Giles Santyr
    • Quebec
      • Sherbrooke, Quebec, Canada, J1N 3C6

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

This study will enroll both adolescent (ages ≥12 and <19 years) and adult (≥19 years) e-cigarette and non-e-cigarette users in six academic hospital centres across Canada.

Description

Inclusion Criteria:

Adolescent arm:

  • Aged ≥12 and <19 years old
  • Either 1) use neither combustible cigarettes nor e-cigarettes or 2) use e-cigarettes exclusively

Adult arm:

  • Aged ≥19 years old
  • Fall into one of the following categories: 1) use neither combustible cigarettes nor e-cigarettes; 2) use combustible cigarettes exclusively, never using e-cigarettes; 3) use e-cigarettes exclusively, never using combustible cigarettes; or 4) use both combustible cigarettes and e-cigarettes currently

Exclusion Criteria:

Adolescent arm:

  • Contraindication to pulmonary function testing and cardiopulmonary exercise testing
  • Have smoked combustible cannabis within the last month and/or have a combustible cannabis smoking history of >1 joint-year
  • Have smoked combustible cigarettes within the last 6 months
  • Have a physician-diagnosed chronic lung disease (such as asthma, cystic fibrosis, or bronchopulmonary dysplasia)
  • Inability to provide written informed consent

Adult arm:

  • Contraindication to pulmonary function testing and cardiopulmonary exercise testing
  • Have smoked combustible cannabis within the last month and/or have a combustible cannabis smoking history of >1 joint-year
  • Currently undergoing treatment for lung cancer
  • Inability to provide written informed consent

No limitations will be placed on the type of e-liquids used by participants; e.g., e-cigarette users of nicotine, tetrahydrocannabinol, and cannabidiol will be all enrolled.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Adults
Canadian adults aged 19 years or older. We will be enrolling e-cigarette-only users, non-e-cigarette and non-combustible cigarette users, combustible cigarette-only users, and dual combustible cigarette-e-cigarette users.
Adolescents
Canadian adolescents aged between 12 and <19 years, inclusive. We will be enrolling e-cigarette-only users, as well as non-e-cigarette and non-combustible cigarette users.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Composite Measure of Small Airways Dysfunction
Time Frame: From enrollment (Baseline) to the end of study participation (36 Months).

Participants meeting at least one of the following criteria will be considered to have small airways dysfunction:

For adolescent participants, these measures will include 1) a change in resistance from 5-20 Hz (R5-R20) >upper limit of normal (ULN) on oscillometry or 2) peak oxygen consumption (VO2)<lower limit of normal (LLN) plus a ventilatory response or minute ventilation/carbon dioxide production (VE/VCO2) nadir >ULN. For adult participants, these measures will include 1) R5-R20 >ULN, 2) disease probability measure functional small airways disease >10% on chest CT, or 3) peak VO2<84% predicted plus a VE/VCO2 nadir >ULN. The proportion of participants meeting at least one of the criteria for small airways dysfunction at any time point will be compared between the vaping and control groups using Chi-square tests. Multivariable logistic regressions will be used to adjust for possible covariates, such as age, sex, and their interaction with vaping/smoking groups.
From enrollment (Baseline) to the end of study participation (36 Months).

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
FEV1
Time Frame: 36 Months
Outcome measured in units of Liters (L) for all study participants.
36 Months
FVC
Time Frame: 36 Months
Outcome measured in units of Liters (L) for all study participants.
36 Months
FEV1/FVC
Time Frame: 36 Months
Outcome measured in units of 0-100% for all study participants.
36 Months
FEV3/FEV6
Time Frame: 36 Months
Outcome measured in units of 0-100% for all study participants.
36 Months
Total Lung Capacity
Time Frame: 36 Months
Outcome measured in units of Liters (L) for all study participants.
36 Months
Diffusion Capacity
Time Frame: 36 Months
Outcome measured in units of mL/min/mmHg for all study participants.
36 Months
Small Airways Resistance R5-R20
Time Frame: 36 Months
Outcome measured in units of kPa/l/s for all study participants.
36 Months
Ventilation Defect Percent
Time Frame: 36 Months
Outcomes measured in units of 0-100% for study participants in the following sites: St. Paul's Hospital (University of British Columbia), BC Children's Hospital (University of British Columbia), the Hospital for Sick Children (University of Toronto), St. Joseph's Healthcare Hamilton (McMaster University).
36 Months
RBC to Membrane Ratio
Time Frame: 36 Months
Outcomes measured in units of a ratio for study participants in the following sites: St. Paul's Hospital (University of British Columbia), BC Children's Hospital (University of British Columbia), the Hospital for Sick Children (University of Toronto), St. Joseph's Healthcare Hamilton (McMaster University).
36 Months
Membrane to Gas Ratio
Time Frame: 36 Months
Outcomes measured in units of a ratio for study participants in the following sites: St. Paul's Hospital (University of British Columbia), BC Children's Hospital (University of British Columbia), the Hospital for Sick Children (University of Toronto), St. Joseph's Healthcare Hamilton (McMaster University).
36 Months
Apparent Diffusion Coefficient
Time Frame: 36 Months
Outcomes measured in units of cm2/s for study participants in the following sites: St. Paul's Hospital (University of British Columbia), BC Children's Hospital (University of British Columbia), the Hospital for Sick Children (University of Toronto), St. Joseph's Healthcare Hamilton (McMaster University).
36 Months
Peak VO2 %predicted
Time Frame: 36 Months
Outcomes measured in units of 0-100% for all study participants.
36 Months
VE/VCO2 nadir
Time Frame: 36 Months
Outcomes measured in units of a ratio for all study participants.
36 Months
Epigenetic Age (Blood Methylation)
Time Frame: 36 Months
Outcomes measured in units of age acceleration residual for all study participants.
36 Months
Differentially Methylated Genes (Blood Methylation)
Time Frame: 36 Months
Outcomes measured in units of beta-values for all study participants.
36 Months
Differentially Expressed Genes (Blood Transcriptome)
Time Frame: 36 Months
Outcomes measured in units of transcripts per million for all study participants.
36 Months
Epigenetic Age (Induced Sputum Methylation)
Time Frame: 36 Months
Outcomes measured in units of age acceleration residual for adolescent study participants in the following sites: BC Children's Hospital (University of British Columbia), the Hospital for Sick Children (University of Toronto), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke).
36 Months
Differentially Methylated Genes (Induced Sputum Methylation)
Time Frame: 36 Months
Outcomes measured in units of beta-values for adolescent study participants in the following sites: BC Children's Hospital (University of British Columbia), the Hospital for Sick Children (University of Toronto), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke).
36 Months
Differentially Expressed Genes (Induced Sputum Transcriptome)
Time Frame: 36 Months
Outcomes measured in units of transcripts per million for adolescent study participants in the following sites: BC Children's Hospital (University of British Columbia), the Hospital for Sick Children (University of Toronto), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke).
36 Months
Epigenetic Age (Bronchial Epithelial Cell and Bronchoalveolar Lavage Methylation)
Time Frame: 36 Months
Outcomes measured in units of age acceleration residual for adult study participants in the following sites: St. Paul's Hospital (University of British Columbia), St. Joseph's Healthcare Hamilton (McMaster University), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke).
36 Months
Differentially Methylated Genes (Bronchial Epithelial Cell and Bronchoalveolar Lavage Methylation)
Time Frame: 36 Months
Outcomes measured in units of beta-values for adult study participants in the following sites: St. Paul's Hospital (University of British Columbia), St. Joseph's Healthcare Hamilton (McMaster University), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke).
36 Months
Differentially Expressed Genes (Bronchial Epithelial Cell and Bronchoalveolar Lavage Transcriptome)
Time Frame: 36 Months
Outcomes measured in units of transcripts per million for adult study participants in the following sites: St. Paul's Hospital (University of British Columbia), St. Joseph's Healthcare Hamilton (McMaster University), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke).
36 Months
Lung Clearance Index
Time Frame: 36 Months
Outcomes measured in counts for adolescent study participants in the following sites: BC Children's Hospital (University of British Columbia), the Hospital for Sick Children (University of Toronto).
36 Months
DPM fSAD
Time Frame: 36 Months
Outcomes measured in units of 0-100% for adult study participants in the following sites: St. Paul's Hospital (University of British Columbia), St. Joseph's Healthcare Hamilton (McMaster University), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke), Clinical Sciences Building (University of Alberta), Ottawa Hospital General Campus (University of Ottawa).
36 Months
LAA856
Time Frame: 36 Months
Outcomes measured in units of 0-100% for adult study participants in the following sites: St. Paul's Hospital (University of British Columbia), St. Joseph's Healthcare Hamilton (McMaster University), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke), Clinical Sciences Building (University of Alberta), Ottawa Hospital General Campus (University of Ottawa).
36 Months
LAA950 (Quantitative Emphysema)
Time Frame: 36 Months
Outcomes measured in units of 0-100% for adult study participants in the following sites: St. Paul's Hospital (University of British Columbia), St. Joseph's Healthcare Hamilton (McMaster University), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke), Clinical Sciences Building (University of Alberta), Ottawa Hospital General Campus (University of Ottawa).
36 Months
Qualitative Emphysema
Time Frame: 36 Months
Outcomes measured in units of 0-100% for adult study participants in the following sites: St. Paul's Hospital (University of British Columbia), St. Joseph's Healthcare Hamilton (McMaster University), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke), Clinical Sciences Building (University of Alberta), Ottawa Hospital General Campus (University of Ottawa).
36 Months
Pulmonary Vascular Volume
Time Frame: 36 Months
Outcomes measured in units of milliliters (mL) for adult study participants in the following sites: St. Paul's Hospital (University of British Columbia), St. Joseph's Healthcare Hamilton (McMaster University), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke), Clinical Sciences Building (University of Alberta), Ottawa Hospital General Campus (University of Ottawa).
36 Months
Mucus Score
Time Frame: 36 Months
Outcomes measured in counts for adult study participants in the following sites: St. Paul's Hospital (University of British Columbia), St. Joseph's Healthcare Hamilton (McMaster University), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke), Clinical Sciences Building (University of Alberta), Ottawa Hospital General Campus (University of Ottawa).
36 Months
Total Airway Counts
Time Frame: 36 Months
Outcomes measured in counts for adult study participants in the following sites: St. Paul's Hospital (University of British Columbia), St. Joseph's Healthcare Hamilton (McMaster University), Centre Hospitalier Universitaire de Sherbrooke (Universite de Sherbrooke), Clinical Sciences Building (University of Alberta), Ottawa Hospital General Campus (University of Ottawa).
36 Months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of British Columbia

Collaborators

Université de Sherbrooke
University of Alberta
McMaster University
University of Toronto
University of Ottawa
British Columbia Cancer Agency
Providence Healthcare
BC Children's Hospital Research Institute

Investigators

  • Principal Investigator: Janice Leung, MD, University of British Columbia

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 25, 2025

Primary Completion (Estimated)

December 31, 2029

Study Completion (Estimated)

December 31, 2029

Study Registration Dates

First Submitted

January 27, 2025

First Submitted That Met QC Criteria

February 5, 2025

First Posted (Actual)

February 11, 2025

Study Record Updates

Last Update Posted (Actual)

March 30, 2026

Last Update Submitted That Met QC Criteria

March 24, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • H24-00374
  • FRN-193735 (Other Grant/Funding Number: Canadian Cancer Society)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Vaping

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Norway

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe