UNC Tobacco Convenience Store Study
Phase: NA
Conditions: Health Behavior
Sponsor: University of North Carolina, Chapel Hill

Complete Title: UNC Tobacco Convenience Store 
Protocol Date: April 13, 2026 
NCT #: NCT07458607 
 
Study Principal Investigator:  
Marissa G. Hall 
University of North Carolina 
email: mghall@unc.edu 
 
 
 
  
 
 

Protocol Synopsis  
 
Study title 
UNC Tobacco Convenience Store Study 
Funder 
National Institute on Drug Abuse and US Food and Drug Administration 
Study rationale 
• 
The United States has proposed to ban menthol as a characterizing 
ﬂavor in cigarettes (i.e., a menthol ban).  
• 
The beneﬁts of a menthol ban could be ampliﬁed by a smoking 
cessation campaign that encourages people who smoke menthol 
cigarettes to quit smoking altogether, rather than switch to diƯerent 
cigarettes. 
Study objectives 
• 
Evaluate whether a menthol ban reduces purchases of combustible 
tobacco compared to no ban. 
• 
Evaluate whether a menthol ban paired with a smoking cessation 
campaign reduces purchases of combustible tobacco more than a 
menthol ban alone.  
Study design 
 
Randomized clinical trial 
Number of 
participants  
~1,185 participants 
Study duration 
Each participant is in the trial for ~1 week. The trial enrollment period is 
expected to last ~24 months. 
Study phases 
  
The trial will have two phases: 
(1) Screening: screening for eligibility and obtaining consent, and  
(2) Intervention: intervention/experimental treatment 
 
Study protocol 
This trial aims to determine whether a quit smoking campaign ampliﬁes the impact of a 
simulated menthol cigarette ban. The trial will enroll ~1,185 adults ages 21 years and older who 
currently smoke menthol cigarettes. Participants will attend 2 in-person study visits at our 
experimental store, spaced approximately 1 week apart. The store will be stocked with a variety of 
tobacco products, food, non-alcoholic beverages, and household goods. At the ﬁrst visit, 
participants will provide written informed consent and will be randomized to 1 of 3 trial arms, 
described further below. At both study visits, participants will shop for items in the store and 
complete computer surveys. Researchers will record in-store purchases and other self-reported 
measures will be assessed via the computer surveys. In between the in-person study visits, 
participants will receive ads via text message based on their trial arm. 
 
Statistical analysis plan 
 
Predictions 
We predict that the likelihood of purchasing combustible tobacco will be lower in the menthol 
ban arm compared to the control arm. We predict that the likelihood of purchasing combustible 
tobacco will be lower in the menthol ban + campaign arm compared to the menthol ban arm.  
In terms of secondary outcomes, we predict that expenditures on combustible tobacco 
products will be lower in the menthol ban arm compared to the control arm, and lower in the 
menthol ban + campaign arm compared to the menthol ban arm. Additionally, we predict that the 

following secondary outcomes will be higher in the menthol ban arm compared to the control arm 
and higher in the menthol ban + campaign arm compared to the menthol ban arm: purchasing non-
combustible tobacco products, attempting to quit smoking, forgoing cigarette use, intentions to 
quit smoking, injunctive norms for quitting smoking, and targeted beneﬁts of quitting smoking. We 
do not have formal predictions about the following secondary outcomes (possible unintended 
consequences): reactance toward ads, reactance towards cigarette options, stigma from ads, and 
stigma from cigarette options.  
 
Statistical methods 
Analyses will be intent-to-treat, including all participants randomized at Visit 1. Inferential tests 
will use a critical alpha of 0.05 or 95% conﬁdence intervals and two-tailed tests. 
We will descriptively present demographic characteristics separately for each trial arm. We will 
not conduct statistical balance tests that compare trial arms on demographic characteristics, 
following CONSORT guidelines for randomized clinical trials. For multi-item measures completed 
by study participants, we will use the mean response to survey measures, assuming suƯicient 
internal consistency reliability (Cronbach's alpha>=0.60). If internal consistency is lower, we will 
consider dropping items or analyzing individual items as separate constructs.  
To examine the impact of trial arm on the primary outcome, we will use mixed-eƯects logistic 
regression. The repeated measures outcome will be whether participants purchased any 
combustible tobacco (no or yes) at each visit. The predictors will be trial arm (using the menthol 
ban arm as the reference group) and study visit (Visit 1 or 2). Analysis will treat the intercept as 
random.  
We will explore whether the impact of trial arm on the primary outcome diƯers by the following 
potential moderator variables: race/ethnicity (Black vs. non-Black), sexual orientation (lesbian, gay, 
or bisexual vs. straight), proportion of cigarettes smoked that are menthol, and smoking frequency 
(daily vs. not daily). For each moderator, we will repeat the analyses, adding the variable and the 
interaction of the variable with trial arm as predictors. If the interaction term is signiﬁcant, we will 
report the impact of trial arm on the primary outcome at each level of the moderator. We will adjust 
p-values for probing moderation analyses for multiple post-hoc tests using a Bonferroni-Holm 
correction. 
Next, we will examine the impact of trial arm on secondary outcomes. We will use mixed-
eƯects linear and logistic regression for outcomes with repeated measures, using the same 
predictors as in the primary outcome model. For smoking quit attempts and forgoing cigarette use 
(measured only once), we will use standard logistic and linear regression, respectively. For 
expenditures on combustible tobacco products, we will code people who did not buy combustible 
tobacco as $0. For all secondary outcomes, we will examine the distribution and adjust the 
modeling strategy as needed.  
 
Sample size needs  
To estimate sample size needs for analyses of the primary trial outcome, we assumed 2 
repeated measures, 3 trial arms of equal size, an intraclass correlation of .50, and 80% retention 
between Visits 1 and 2. We assumed 60% of the control arm would purchase combustible tobacco, 
in line with two prior studies.1,2 Power analyses were conducted used mixed-eƯects logistic 
regression in SAS. We estimated that enrolling ~1,185 people (~395 per arm) would provide 80% 
power to detect a diƯerence of 9 percentage points between arms in participants who made 
purchases. This eƯect size is in line with prior studies of menthol ban eƯects and smoking 
cessation campaign eƯects.3,4  
 

References 
1. 
Shadel WG, Martino SC, Setodji C, et al. Placing antismoking graphic warning posters at 
retail point-of-sale locations increases some adolescents’ susceptibility to future smoking. 
Nicotine and Tobacco Research. 2019;21(2):220-226. 
2. 
Guillory J, Kim AE, Nonnemaker JM, et al. EƯect of menthol cigarette and other menthol 
tobacco product bans on tobacco purchases in the RTI iShoppe virtual convenience store. 
Tob Control. 2020;29(4):452-459. 
3. 
Guillory J, Curry L, Farrelly M, et al. Reach, receptivity, and beliefs associated with the Fresh 
Empire Campaign to prevent and reduce cigarette use among youth in the United States. 
Am J Health Promot. 2022;36(5):789-800. 
4. 
Willoughby JF, Noar SM. Fifteen Years after a 10-year Retrospective: The State of Health 
Mass Mediated Campaigns. J Health Commun. 2022;27(6):362-374.