An interventional study of Health Warnings and No Warnings in Waterpipe Tobacco Smoking, sponsored by Wake Forest University Health Sciences. Completed at 1 site in United States. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-02-02.
Sponsored by Wake Forest University Health Sciences · Not applicable, Interventional, and Prevention
The purpose of the study is to assess the effectiveness of health warnings on waterpipe smoking behavior in a real-world setting. The primary hypothesis is that hookah café customers who are in the intervention (warning) arm will smoke less than customers who are in the control (no warning) arm, determined by differences in the boost in expired carbon monoxide from café entry to after café exit.
Expired carbon monoxide is an objective biological marker of combustible tobacco smoking and is strongly correlated with the amount of smoke inhaled. In the intervention arm, warning messages will be displayed at various agreed-upon locations in the café, such as on hookah pipes, tables, countertops, walls, and menus. The goal is to maximize the potential for customers to be exposed to warnings. Participants will be patrons of the café and will be recruited before entering the café. Participants will complete a brief survey and provide a breath sample to measure expired carbon monoxide. When leaving the café, they will complete another survey and provide a second breath sample.
68 studies on the registry are indexed under Tobacco Smoking; 26 are open to participants now.
This study's enrollment of 977 is above the median of 111 across 60 interventional studies indexed under Tobacco Smoking.
Browse Tobacco Smoking studies →Wake Forest University Health Sciences is the lead sponsor of 1,320 studies on the registry; 199 are open to participants now.
Of its 323 completed or terminated interventional studies of FDA-regulated products, 243 (75%) have results posted.
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Exclusion Criteria:
Cafes will display text-only warning signs
Behavioral: Health Warnings
No warnings posted in the hookah café
Behavioral: No Warnings
Text-only warnings about one health harm will be displayed in the hookah cafés where data collection is being conducted.
No warnings posted in the hookah café
Change in Expired Carbon Monoxide (eCO Boost)
Change in eCO from baseline (before entry into the hookah café) to follow-up (upon exit from the hookah café) - eCO will be measured with the Bedfont Micro+ Smokerlyzer. Higher scores represent higher concentrations of Carbon Monoxide (CO), which is correlated with greater waterpipe use.
Time frame: Baseline and after exiting the café up to 10 hours
Behavioral Intention
Participants will be asked at three items assessing their anticipated hookah smoking within the next month. Items will be averaged to create a composite score of intent to continue the behavior within the next month. 1. How interested are you in smoking tobacco in a hookah in the next month? 2. How likely are you to smoke tobacco in a hookah in the next month? 3. How much do you plan to smoke tobacco in a hookah in the next month? Response options: (1) Not at all, (2) Very little, (3) Somewhat, (4) Quite a bit, (5) Very much
Time frame: at exit; up to 10 hours
Quit Motivation
One item to measure participants' motivation to quit smoking hookah, rated on a 1-10 scale of Not at all motivated to Extremely motivated
Time frame: at exit; up to 10 hours
Hookah Use Behavior
Participants will be asked a variety of items to assess their hookah smoking behaviors within the café. Items will be scored individually. 1. Did you smoke hookah in this café/lounge/bar today? (1) Yes, (2) No 2. (If no) Why didn't you smoke hookah in this café/lounge/bar today? Free text response 3. (If yes) Compared to a typical night, how much did you smoke? (1) Less hookah than usual, (2) About the same amount of hookah as usual, (3) More hookah than usual, (4) This was my first time smoking hookah 4. (If less) Why did you smoke less than usual? Free text response 5. (If more) Why did you smoke more than usual? Free text response
Time frame: at exit; up to 10 hours
Subjective Experiences of Smoking Hookah
Eight items from the Product Evaluation Scale (Hatsukami et al. 2013) will be used to assess participants' subjective experiences of smoking hookah. Items scores will be averaged across the subscale. 1. Was it satisfying? 2. Did it taste good? 3. Did you enjoy the sensations in your mouth? 4. Did you enjoy it? 5. Did it make you dizzy? 6. Did it make you nauseous? 7. Was it too much nicotine? 8. Were there bothersome side effects? Response options: (1) Not at all - (7) Extremely
Time frame: at exit; up to 10 hours
Knowledge
Four items to assess participants' knowledge of health harms based on warning statements used across the study. We will calculate a sum score for each individual with higher scores indicating more accurate knowledge. Response options: True / False / I don't know
Time frame: at exit; up to 10 hours
Beliefs
Four items to assess the participants' agreement with statements of how each of the four health harms utilized across the study apply to their own health. We will calculate a mean score across all four items for each individual, where higher scores indicate stronger beliefs about personal harm from hookah smoking. Response options: (1) Strongly disagree to (5) Strongly agree
Time frame: at exit; up to 10 hours
Warning Recall
One Y/N item to assess participants' exposure to warnings. If participants report warning exposure, an open-ended item will assess warning recall.
Time frame: at exit; up to 10 hours
Warning Recognition
Participants in the intervention arm will be asked to select the warning(s) that they saw at the café from four possible warnings. For each warning message that they report having seen, they will be asked to select where they saw the warning from a list of possible locations. (Intervention arm only)
Time frame: at exit; up to 10 hours
Social Interaction
For each warning selected in the Warning Recognition section, participants will be asked if they discussed the warning with others. If they answer positively, they will be given a list of topics to choose from to describe what they talked about, including a free-text option.
Time frame: at exit; up to 10 hours
Perceived Influence of Warning on Smoking Behavior Answers
Participants will be asked whether they changed their smoking behavior as a result of the warning(s) they saw (as reported in the Warning Recognition section). They will be asked to report whether they smoked more, less, or the same amount as they usually do. These items will be asked for each warning the participant reports seeing.
Time frame: at exit; up to 10 hours
Time Spent in the café
Duration of time in café will be calculated from the time of completion of eCO measurement at Time 1 to start of survey at Time 2. Additionally, we will utilize a subjective measure of time spent in the café: Compared to what you planned, how long did you stay at the café/lounge/bar? (Longer, shorter, about the same).
Time frame: at exit; up to 10 hours
This is a cluster randomized crossover trial in which hookah cafes started in the No Warning Control condition and then crossed over to the Health Warnings Intervention, in which they were randomized to display one of four health warning messages (Milestones). Participants were cafe patrons on the days/nights that data collection was being conducted. Participants were only permitted to participate in one instance of data collection at one hookah cafe. Some cafes only had Control period.
| Milestone | Hookah Cafes in Atlanta, GA |
|---|---|
| Started | 507 |
| Completed | 479 |
| Not completed | 28 |
| Withdrew: Lost to follow-up | 12 |
| Withdrew: Withdrawal by subject | 15 |
| Withdrew: Noncompliance with protocol | 1 |
| Milestone | Hookah Cafes in Atlanta, GA |
|---|---|
| Started | 470 |
| Lung damage warning | 148 |
| Heart damage warning | 104 |
| Co poison warning | 112 |
| Fetal damage warning | 106 |
| Completed | 431 |
| Not completed | 39 |
| Withdrew: Lost to follow-up | 15 |
| Withdrew: Withdrawal by subject | 10 |
| Withdrew: Noncompliance with protocol | 14 |
Change in eCO from baseline (before entry into the hookah café) to follow-up (upon exit from the hookah café) - eCO will be measured with the Bedfont Micro+ Smokerlyzer. Higher scores represent higher concentrations of Carbon Monoxide (CO), which is correlated with greater waterpipe use.
| parts per million | No Warning Control | Health Warning Intervention |
|---|---|---|
| Change in Expired Carbon Monoxide (eCO Boost) | 25.7 ± 2.93 | 23.5 ± 2.91 |
Participants will be asked at three items assessing their anticipated hookah smoking within the next month. Items will be averaged to create a composite score of intent to continue the behavior within the next month. 1. How interested are you in smoking tobacco in a hookah in the next month? 2. How likely are you to smoke tobacco in a hookah in the next month? 3. How much do you plan to smoke tobacco in a hookah in the next month? Response options: (1) Not at all, (2) Very little, (3) Somewhat, (4) Quite a bit, (5) Very much
Results for this outcome have not been posted.
One item to measure participants' motivation to quit smoking hookah, rated on a 1-10 scale of Not at all motivated to Extremely motivated
Results for this outcome have not been posted.
Participants will be asked a variety of items to assess their hookah smoking behaviors within the café. Items will be scored individually. 1. Did you smoke hookah in this café/lounge/bar today? (1) Yes, (2) No 2. (If no) Why didn't you smoke hookah in this café/lounge/bar today? Free text response 3. (If yes) Compared to a typical night, how much did you smoke? (1) Less hookah than usual, (2) About the same amount of hookah as usual, (3) More hookah than usual, (4) This was my first time smoking hookah 4. (If less) Why did you smoke less than usual? Free text response 5. (If more) Why did you smoke more than usual? Free text response
Results for this outcome have not been posted.
Eight items from the Product Evaluation Scale (Hatsukami et al. 2013) will be used to assess participants' subjective experiences of smoking hookah. Items scores will be averaged across the subscale. 1. Was it satisfying? 2. Did it taste good? 3. Did you enjoy the sensations in your mouth? 4. Did you enjoy it? 5. Did it make you dizzy? 6. Did it make you nauseous? 7. Was it too much nicotine? 8. Were there bothersome side effects? Response options: (1) Not at all - (7) Extremely
Results for this outcome have not been posted.
Four items to assess participants' knowledge of health harms based on warning statements used across the study. We will calculate a sum score for each individual with higher scores indicating more accurate knowledge. Response options: True / False / I don't know
Results for this outcome have not been posted.
Four items to assess the participants' agreement with statements of how each of the four health harms utilized across the study apply to their own health. We will calculate a mean score across all four items for each individual, where higher scores indicate stronger beliefs about personal harm from hookah smoking. Response options: (1) Strongly disagree to (5) Strongly agree
Results for this outcome have not been posted.
One Y/N item to assess participants' exposure to warnings. If participants report warning exposure, an open-ended item will assess warning recall.
Results for this outcome have not been posted.
Participants in the intervention arm will be asked to select the warning(s) that they saw at the café from four possible warnings. For each warning message that they report having seen, they will be asked to select where they saw the warning from a list of possible locations. (Intervention arm only)
Results for this outcome have not been posted.
For each warning selected in the Warning Recognition section, participants will be asked if they discussed the warning with others. If they answer positively, they will be given a list of topics to choose from to describe what they talked about, including a free-text option.
Results for this outcome have not been posted.
Participants will be asked whether they changed their smoking behavior as a result of the warning(s) they saw (as reported in the Warning Recognition section). They will be asked to report whether they smoked more, less, or the same amount as they usually do. These items will be asked for each warning the participant reports seeing.
Results for this outcome have not been posted.
Duration of time in café will be calculated from the time of completion of eCO measurement at Time 1 to start of survey at Time 2. Additionally, we will utilize a subjective measure of time spent in the café: Compared to what you planned, how long did you stay at the café/lounge/bar? (Longer, shorter, about the same).
Results for this outcome have not been posted.
Collected over Adverse event data were collected during the time that the participant was in the cafe, approximately 3 hours.. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Control - No Warnings | 0/507 (0%) | 0/507 (0%) | 0/507 (0%) |
| Intervention - Health Warnings | 0/470 (0%) | 0/470 (0%) | 0/470 (0%) |
| Age, Continuous(Years) | No Warning Control | Health Warning Intervention | Total |
|---|---|---|---|
| Mean | 30.9 ± 6.9 | 31.5 ± 7.3 | 31.2 ± 7.1 |
| Sex/Gender, Customized(Participants) | No Warning Control | Health Warning Intervention | Total |
|---|---|---|---|
| Female | 295 | 289 | 584 |
| Male | 203 | 177 | 380 |
| Unknown | 9 | 4 | 13 |
| Ethnicity (NIH/OMB)(Participants) | No Warning Control | Health Warning Intervention | Total |
|---|---|---|---|
| Hispanic or Latino | 35 | 26 | 61 |
| Not Hispanic or Latino | 458 | 427 | 885 |
| Unknown or Not Reported | 14 | 17 | 31 |
| Race (NIH/OMB)(Participants) | No Warning Control | Health Warning Intervention | Total |
|---|---|---|---|
| American Indian or Alaska Native | 4 | 6 | 10 |
| Asian | 38 | 28 | 66 |
| Native Hawaiian or Other Pacific Islander | 4 | 0 | 4 |
| Black or African American | 389 | 380 | 769 |
| White | 12 | 14 | 26 |
| More than one race | 23 | 19 | 42 |
| Unknown or Not Reported | 37 | 23 | 60 |
| Region of Enrollment(participants) | No Warning Control | Health Warning Intervention | Total |
|---|---|---|---|
| United States | 507 | 470 | 977 |
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Wake Forest University Health Sciences