Effect of Waterpipe Size on Smoking Behavior and Exposures

Understanding the Effect of Waterpipe Size on Smoking Behavior, Toxicant Exposures and Subjective Experiences

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05705375

Enrollment

Registered

2023-01-30

Start date

2022-04-22

Completion date

2024-03-30

Last updated

2025-11-05

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Waterpipe Size

Brief summary

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.

Detailed description

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.

Interventions

OTHERWaterpipe size

Participants 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.

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

OTHER

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

21 Years to 39 Years

Healthy volunteers

Yes

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)

Design outcomes

Primary

Measure	Time frame	Description
Waterpipe Evaluation Scale	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.
Duke Sensory Questionnaire	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).
Harm Perception Questionnaire	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.
Saliva Nicotine	Immediately after the exposure (smoking)	How participants' nicotine concentrations change based on the different smoked waterpipe sizes
Puff Topography: Smoking Time	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.
Puff Topography: Cumulative Puff Time	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.
Puff Topography: Puff Duration	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.
Puff Topography: Average Flow Rate	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.
Puff Topography: Number of Puffs	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.
Puff Topography: Total Smoke Volume Inhaled	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	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	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.

Countries

United States

Participant flow

Participants by arm

Arm	Count
Waterpipe Regular Smokers waterpipe regular smokers will be invited for 3 lab visits where they are allocated (random order) to smoke 3 waterpipe different sizes. Waterpipe size: Participants 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.	40
Total	40

Baseline characteristics

Characteristic	Waterpipe Regular Smokers
Age, Continuous	24.9 years STANDARD_DEVIATION 3.5
Exhaled Carbon Monoxide	1.2 PPM STANDARD_DEVIATION 0.2
Race (NIH/OMB) American Indian or Alaska Native	0 Participants
Race (NIH/OMB) Asian	26 Participants
Race (NIH/OMB) Black or African American	5 Participants
Race (NIH/OMB) More than one race	0 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants
Race (NIH/OMB) White	9 Participants
Region of Enrollment United States	40 Participants
Saliva Nicotine	9 ng/mL STANDARD_DEVIATION 3.5
Sex: Female, Male Female	11 Participants
Sex: Female, Male Male	29 Participants

Adverse events

Event type	EG000 affected / at risk	EG001 affected / at risk	EG002 affected / at risk
deaths Total, all-cause mortality	0 / 40	0 / 40	0 / 40
other Total, other adverse events	0 / 40	0 / 40	0 / 40
serious Total, serious adverse events	0 / 40	0 / 40	0 / 40

Outcome results

Primary

Duke Sensory Questionnaire

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).

Time frame: Immediately after the exposure (smoking)

Arm	Measure	Value (MEAN)	Dispersion
Small Waterpipe	Duke Sensory Questionnaire	4.4 units on a scale	Standard Deviation 0.9
Medium Waterpipe	Duke Sensory Questionnaire	4.0 units on a scale	Standard Deviation 0.8
Large Waterpipe	Duke Sensory Questionnaire	3.8 units on a scale	Standard Deviation 0.9

Primary

Harm Perception Questionnaire

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.

Time frame: Immediately after the exposure (smoking)

Arm	Measure	Value (MEAN)	Dispersion
Small Waterpipe	Harm Perception Questionnaire	3.5 units on a scale	Standard Deviation 0.5
Medium Waterpipe	Harm Perception Questionnaire	3.7 units on a scale	Standard Deviation 0.2
Large Waterpipe	Harm Perception Questionnaire	3.8 units on a scale	Standard Deviation 0.2

Primary

Puff Topography: Average Flow Rate

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.