Hookah SmokingNCT04661683
Secondhand Effects of Hookah (i.e., Waterpipe) Smoke and Aerosol
A study testing Combustible Hookah Smoke, Electronic Hookah Aerosol and Clean Room Air in people with Hookah Smoking and Secondhand Aerosol, run by University of California, Los Angeles at 1 site in United States.
Trial summary
In the United States, secondhand smoke is the third leading preventable cause of death. Flavored hookah (waterpipe) tobacco smoking, a highly social activity common in hookah bars, is a key source of SHS exposure. Read more about this study
- Who is it for?
- Ages 21 to 49 yearsHealthy volunteers can take part
- Conditions the study is for
- Hookah Smoking, Secondhand Aerosol, Vascular Stiffness
- What is being tested?
- Combustible Hookah Smoke, Electronic Hookah Aerosol and Clean Room Air
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- 1 siteUnited States
- Study dates
- 25 Jun 2021to 15 Apr 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 21 to 49 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 21-49 years old
- Never a smoker: do not use any tobacco products or nicotine delivery systems, including cigarettes, cigars (traditional and filtered), cigarillos, hookah, smokeless tobacco (i.e., loose snus, moist snuff, dip, spit, or chewing tobacco), pipe tobacco, snus pouches, dissolvable tobacco or vaping.
- no evidence of cardiopulmonary disease by history/physical
- blood pressure (BP) < 140/90 mmHg
- resting heart rate (HR) < 100 bpm
- BMI >18 or < 30kg•m2
- no prescription medication
- No exposure to environmental tobacco smoke for at least one week prior to the study date.
Who cannot join
- exhaled carbon monoxide >6 ppm
- (+) pregnancy test
- other conditions deemed unsafe to participate, such as breastfeeding
Trial locations and contacts
1 site in 1 country.
United States1 site
University of California, Los Angeles
Los Angeles, California, 90095-8361
About this study
Official title: Investigating the Secondhand Effects of Hookah Smoking and Vaping
In the United States, secondhand smoke is the third leading preventable cause of death. Flavored hookah (waterpipe) tobacco smoking, a highly social activity common in hookah bars, is a key source of SHS exposure. While smoke-free air laws have decreased exposure to secondhand smoke, the majority of laws do not include hookah smoking. Thus, as a social outlet for youth and young adults, hookah smoke exposure may harm non-smokers, including women of reproductive age or pregnant, hookah bar workers, children, and individuals with heart and lung disease. While more is known on the acute effects of active hookah smoking and the literature is emerging on active e-hookah vaping, little is known about the acute vascular effects of secondhand exposure to hookah smoke and aerosol. The study aims to examine the acute effects of secondhand exposure of hookah smoke and aerosol on endothelial and vascular function. Eligible volunteers will be invited to participate in a total of 3 study visits (2-3 hours each): e-hookah aerosol exposure, charcoal-heated hookah smoke exposure and smoke-free room air. Non-invasive blood pressure and blood flow measurements will be taken before and after the exposure sessions.
- Conditions
- Hookah Smoking, Secondhand Aerosol, Vascular Stiffness, Vaping
- Being tested
- Combustible Hookah Smoke, Electronic Hookah Aerosol, Clean Room Air
- Medical subject headings
- Water Pipe Smoking, Vaping
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Combustible Hookah SmokeOther
Exposure to combustible hookah smoke for a duration of 60 minutes.
Electronic Hookah AerosolOther
Exposure to electronic hookah aerosol for a duration of 60 minutes.
Clean Room AirOther
Exposure to room air for a duration of 60 minutes.
| Study group | Role | What they receive |
|---|---|---|
| Exposure to Combustible Hookah Smoke | Experimental | Participants will be exposed to combustible hookah smoke. To mitigate the impact of carryover effects, the exposure sessions will be separated by a minimum of 7-days. Receives: Other: Combustible Hookah Smoke |
| Exposure to Electronic Hookah Aerosol | Experimental | Participants will be exposed to electronic hookah aerosol. To mitigate the impact of carryover effects, the exposure sessions will be separated by a minimum of 7-days. Receives: Other: Electronic Hookah Aerosol |
| Exposure to Clean Air | Experimental | Participants will be exposed to Clean Room Air. To mitigate the impact of carryover effects, the exposure sessions will be separated by a minimum of 7-days. Receives: Other: Clean Room Air |
What is being measured
The primary outcome is the main question the study is designed to answer.
Flow-Mediated Dilation (FMD)
Using ultrasound, FMD of the brachial artery induced by reactive hyperemia, will be used to measure endothelium-dependent vasodilator function. Baseline diameter and velocity will be recorded for 45 seconds and resumed 30 seconds before cuff deflation and continuously for 2 minutes after deflation to obtain true peak vasodilatory response.
Measured: Pre- and post- the 60-minute exposure sessions
Arterial stiffness
Using applanation tonometry, pulse wave velocity will be used to measure cebtral arterial stiffness.
Measured: Pre- and post- the 60-minute exposure sessions
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Dec 2020
- Study start25 Jun 2021
- Primary completion15 Dec 2026 (estimated)
- Study completion15 Apr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hookah SmokingStudies of the same condition, open and under way.
- More trials run by University of California, Los AngelesThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 12 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, Los Angeles
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Mary Rezk-Hanna, PhD, University of California, Los Angeles
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04661683
- Sponsor's protocol ID
- 20-001570
- Status last verified
- Apr 2026
- First submitted
- 3 Dec 2020
- Last updated
- 22 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 22 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Investigating the Secondhand Effects of Hookah Smoking and Vaping
- ClinicalTrials.gov ID
- NCT04661683
- Acronym / sponsor ID
- 20-001570
- Conditions
- Hookah Smoking, Secondhand Aerosol, Vascular Stiffness, Vaping
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 12 participants (estimated)
- Lead sponsor
- University of California, Los AngelesUniversity, hospital or other
- Study start
- 25 Jun 2021 (actual)
- Primary completion
- 15 Dec 2026 (estimated)
- Study completion
- 15 Apr 2027 (estimated)
- First posted
- 10 Dec 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
In the United States, secondhand smoke is the third leading preventable cause of death. Flavored hookah (waterpipe) tobacco smoking, a highly social activity common in hookah bars, is a key source of SHS exposure. While smoke-free air laws have decreased exposure to secondhand smoke, the majority of laws do not include hookah smoking. Thus, as a social outlet for youth and young adults, hookah smoke exposure may harm non-smokers, including women of reproductive age or pregnant, hookah bar workers, children, and individuals with heart and lung disease. While more is known on the acute effects of active hookah smoking and the literature is emerging on active e-hookah vaping, little is known about the acute vascular effects of secondhand exposure to hookah smoke and aerosol. The study aims to examine the acute effects of secondhand exposure of hookah smoke and aerosol on endothelial and vascular function. Eligible volunteers will be invited to participate in a total of 3 study visits (2-3 hours each): e-hookah aerosol exposure, charcoal-heated hookah smoke exposure and smoke-free room air. Non-invasive blood pressure and blood flow measurements will be taken before and after the exposure sessions.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Exposure to Combustible Hookah Smoke | Experimental | Other: Combustible Hookah SmokeParticipants will be exposed to combustible hookah smoke. To mitigate the impact of carryover effects, the exposure sessions will be separated by a minimum of 7-days. |
| Exposure to Electronic Hookah Aerosol | Experimental | Other: Electronic Hookah AerosolParticipants will be exposed to electronic hookah aerosol. To mitigate the impact of carryover effects, the exposure sessions will be separated by a minimum of 7-days. |
| Exposure to Clean Air | Experimental | Other: Clean Room AirParticipants will be exposed to Clean Room Air. To mitigate the impact of carryover effects, the exposure sessions will be separated by a minimum of 7-days. |
Who may qualify
- Ages
- 21 to 49 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (8 listed)
- 21-49 years old
- Never a smoker: do not use any tobacco products or nicotine delivery systems, including cigarettes, cigars (traditional and filtered), cigarillos, hookah, smokeless tobacco (i.e., loose snus, moist snuff, dip, spit, or chewing tobacco), pipe tobacco, snus pouches, dissolvable tobacco or vaping.
- no evidence of cardiopulmonary disease by history/physical
- blood pressure (BP) < 140/90 mmHg
- resting heart rate (HR) < 100 bpm
Key exclusion criteria (3 listed)
- exhaled carbon monoxide >6 ppm
- (+) pregnancy test
- other conditions deemed unsafe to participate, such as breastfeeding
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Combustible Hookah SmokeExposure to combustible hookah smoke for a duration of 60 minutes. | Other | Exposure to Combustible Hookah Smoke |
| Electronic Hookah AerosolExposure to electronic hookah aerosol for a duration of 60 minutes. | Other | Exposure to Electronic Hookah Aerosol |
| Clean Room AirExposure to room air for a duration of 60 minutes. | Other | Exposure to Clean Air |
Primary outcome
Flow-Mediated Dilation (FMD)
Time frame: Pre- and post- the 60-minute exposure sessions
Using ultrasound, FMD of the brachial artery induced by reactive hyperemia, will be used to measure endothelium-dependent vasodilator function. Baseline diameter and velocity will be recorded for 45 seconds and resumed 30 seconds before cuff deflation and continuously for 2 minutes after deflation to obtain true peak vasodilatory response.
Arterial stiffness
Time frame: Pre- and post- the 60-minute exposure sessions
Using applanation tonometry, pulse wave velocity will be used to measure cebtral arterial stiffness.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Apr 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Combustible Hookah Smoke, Electronic Hookah Aerosol and Clean Room Air in people with Hookah Smoking and Secondhand Aerosol, run by University of California, Los Angeles at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 22 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Flow-Mediated Dilation (FMD) (time frame: Pre- and post- the 60-minute exposure sessions). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Apr 2026.