University of Texas at Arlington
Arlington, Texas, 76019, United States
Completed
NCT Number: NCT05705375
Effect of Waterpipe Size on Smoking Behavior and Exposures
The goal of this clinical trial is to learn how waterpipe (WP) size affects smoking behavior, toxicant exposure, and subjective experiences in young adult WP smokers (ages 21-39). The main questions it aims to answer are:
* Does WP size change puffing behavior? * Does WP size change exposure to nicotine and carbon monoxide? * Does WP size change perceptions of harm, satisfaction, craving, or withdrawal?
Participants will smoke small, medium, and large WPs in separate sessions. Researchers will measure puffing behavior, saliva nicotine, exhaled carbon monoxide, and survey responses before and after each session.
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Notify MeKey information
Conditions
Age range
21 year–39 year
Sex eligibility
All sexes
Study type
Interventional
Phase
Not applicable
Primary location
About this study
This study will examine the effect of waterpipe (WP) size manipulation on smoking behavior, toxicant exposure, and subjective experiences among young adult WP smokers. A total of 40 participants ages 21-39 will complete a 2x3 crossover design, where the within-subject factors are time (pre vs. post WP smoking) and study condition (small vs. medium vs. large). Each participant will attend three 45-minute laboratory sessions, each using a different WP size.
Aim 1: To examine the effect of WP size on puffing behavior and toxicant exposure. Puff topography parameters (puff number, duration, average puff volume, total inhaled volume, and inter-puff interval) will be measured during smoking. Exhaled CO and saliva nicotine concentrations will be measured pre- and post-session.
Aim 2: To examine the effect of WP size on harm perception and subjective experiences. Outcomes include harm perception, WP Evaluation Scale, Duke Sensory Questionnaire, Questionnaire of Smoking Urges (brief), and Minnesota Nicotine Withdrawal Scale.
This project will generate novel evidence on how WP size influences smoking behavior, exposure to nicotine and CO, and user perceptions. Findings will inform the FDA on the potential impact of WP size regulation and help guide the development of size-specific standards to protect public health.
Who can participate
Healthy volunteers accepted: Yes
Only the study team can determine whether someone qualifies for participation.
Inclusion criteria
- regular waterpipe smokers (smoking at least once a week for the past 6 months)
- generally healthy and
- able to provide written informed consent; and willing to attend the 3 lab sessions
Exclusion criteria
- history of chronic diseases such as diabetes, high blood cholesterol, hepatic disease
- respiratory chronic diseases
- cardiovascular diseases including low or high blood pressure (BP)
Treatment and study plan
Waterpipe size
OtherParticipants will have 3 lab visits where they are allocated (random order) to smoke a small waterpipe in one visit, smoke a medium waterpipe in a second visit and smoke a large waterpipe in a third visit.
Primary outcomes
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Waterpipe Evaluation Scale
Time frame: Immediately after the exposure (smoking)
An 11-item questionnaire assessing participants' subjective experience of smoking waterpipe (WP) tobacco. Each item is scored on a 7-point Likert scale (1 = "not at all" to 7 = "extremely"). For analysis, item scores were averaged across the 11 items to produce a mean WES score for each WP size, with higher scores indicating a more satisfactory smoking experience. The scale captures aspects such as satisfaction, taste, cravings, and sensory enjoyment in the throat and chest.
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Duke Sensory Questionnaire
Time frame: Immediately after the exposure (smoking)
A 9-item questionnaire assessing participants' sensory experience of smoking waterpipe (WP) tobacco. Each item is scored on a 7-point Likert scale (1 = "not at all" to 7 = "extremely"). Item scores were averaged across the 9 items to produce a mean DSQ score for each WP size, with higher scores indicating a more positive sensory experience (e.g., satisfaction, perceived nicotine strength, and puff intensity).
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Harm Perception Questionnaire
Time frame: Immediately after the exposure (smoking)
This is a 3-item scale assessing participants' perception of the harmfulness of waterpipe (WP) tobacco smoking. Each item is scored on a 7-point Likert scale ranging from 1 = "a lot less harmful" to 7 = "a lot more harmful." Item scores were averaged across the 3 items to produce a mean harm perception score for each WP size, with higher scores indicating greater perceived harm.
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Saliva Nicotine
Time frame: Immediately after the exposure (smoking)
How participants' nicotine concentrations change based on the different smoked waterpipe sizes
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Puff Topography: Smoking Time
Time frame: During the exposure (smoking), up to 45 mins
The total time spent smoking during a single WP session, measured in minutes. Longer times indicate greater duration of smoking across WP sizes.
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Puff Topography: Cumulative Puff Time
Time frame: During the exposure (smoking), up to 45 mins
The total time spent actively inhaling smoke across all puffs in a WP session, measured in minutes using a puff topography device. Higher values indicate more total inhalation time.
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Puff Topography: Puff Duration
Time frame: During the exposure (smoking), up to 45 mins
The average length of each puff in seconds, measured using a puff topography device in the WP hose. Longer puff duration indicates deeper inhalation per puff.
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Puff Topography: Average Flow Rate
Time frame: During the exposure (smoking), up to 45 mins
The average rate of smoke inhaled per second during puffing, measured in liters per minute with a puff topography device. Higher flow rates indicate faster inhalation.
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Puff Topography: Number of Puffs
Time frame: During the exposure (smoking), up to 45 mins
The total number of puffs taken during a WP session, measured using a puff topography device. Higher counts indicate more frequent puffing.
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Puff Topography: Total Smoke Volume Inhaled
Time frame: During the exposure (smoking), up to 45 mins
Total smoke inhaled during a single WP session, measured in liters using a puff topography device in the WP hose. Higher values indicate greater smoke intake across WP sizes.
-
Puff Topography: Puff Volume Average
Time frame: During the exposure (smoking), up to 45 mins
Mean volume of each puff during a WP session, measured in liters using a puff topography device in the WP hose. Higher values indicate larger puff sizes across WP sizes.
-
Puff Topography: Maximum Puff Volume
Time frame: During the exposure (smoking), up to 45 mins
The largest single puff volume inhaled during a WP session, measured in liters using a puff topography device. Higher values indicate the strongest inhalation effort across puffs.
Sponsors and collaborators
Lead sponsor
The University of Texas at Arlington
Other
Registry information
Official study title
Understanding the Effect of Waterpipe Size on Smoking Behavior, Toxicant Exposures and Subjective Experiences
Important dates
- Study start
- 2022
- Primary completion
- 2024
- Study completion
- 2024
- First posted
- Jan 30, 2023
- Registry last updated
- Nov 5, 2025
OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.
View the official ClinicalTrials.gov record (opens in a new tab)This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.