Testing Product Messages in Colombia
Phase: NA
Conditions: Obesity
Sponsor: University of North Carolina, Chapel Hill

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Testing Product Messages in Colombia 
 
Study Protocol and Statistical Analysis Plan 
NCT05783726 
Version Date: 04/24/2023 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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PROTOCOL TITLE: Testing Product Messages in Colombia 
Lead Investigator: 
Lindsey Smith Taillie, PhD  
 University of North Carolina at Chapel Hill 
 
 
I confirm that I have read this protocol and understand it.    
 
Principal Investigator Name:   
 
 
Lindsey Smith Taillie  
 
 
Date:   
 
 
 
 
 
04/24/2023 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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TABLE OF CONTENTS 
Protocol Synopsis ..................................................................................................................... 4 
BACKGROUND AND RATIONALE ............................................................................................................................... 6 
STUDY OBJECTIVE ..................................................................................................................................................... 6 
INVESTIGATIONAL PLAN (BRIEF OVERVIEW) ............................................................................................................ 7 
STUDY PROCEDURES (WHAT WILL BE DONE) .......................................................................................................... 8 
SCREENING AND MONITORING EVALUATIONS AND MEASUREMENTS .................................................................. 9 
STATISTICAL ANALYSIS PLAN ................................................................................................................................ 100 
SAFETY MANAGEMENT ........................................................................................................................................ 122 
DATA COLLECTION AND MANAGMENT ............................................................................................................... 122 
RECRUITMENT STRATEGY ....................................................................................................................................... 12 
CONSENT PROCESS ............................................................................................................................................... 122 
INFORMED CONSENT FORM ................................................................................................................................ 143 
PLANS FOR PUBLICATION ..................................................................................................................................... 144 
REFERENCES ......................................................................................................................................................... 155 
 
 
 

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PROTOCOL SYNOPSIS 
 
Study Title 
Testing Product Messages in Colombia 
Funder 
Bloomberg Philanthropies  
Study Rationale 
According to the WHO, obesity and overweight are health 
conditions afflicting over a billion people worldwide. Obesity and 
overweight can lead to numerous health problems including 
cardiovascular disease, diabetes, musculoskeletal disorders, and 
various types of cancers (1). Colombia is not immune to this global 
health problem. In Colombia in 2016, more than half of adults were 
overweight and more than 22 percent of adults were obese (2). 
Additionally, obesity and overweight impact Colombian children. 
The Colombian Ministry of Health reports that approximately 18% 
of Colombian youth are overweight (3). As a result of this increasing 
health problem, the Colombian government has begun to take 
actions to address overweight and obesity in Colombia. The 
Colombian government (the Congress, the Ministry of Health) 
recently approved a law that would require warnings on the front of 
packages high in critical nutrients to inform consumers and reduce 
the intake of these unhealthy foods and beverages (4). Similar laws 
have been implemented in countries around the world, such as 
Chile, Peru, and Israel (5). Research is needed to inform the design 
of this law. The purpose of this study is to test the potential 
effectiveness of different labels to be used on the packaging of 
foods and drinks to promote healthy diets in Colombia. This 
research is time sensitive and politically relevant and will help to 
inform Colombian Ministry of Health as to how product labeling will 
help to dissuade consumption and inform Colombians of product 
healthfulness prior to the implementation. 
Study Objective(s) 
Primary 
• To identify the impact of nutrient warnings on product 
selection and other outcomes compared to GDA labels, 
Nutriscore labels, and a no-label control, in Colombia. 
Secondary 
• 
To determine the effect of the nutrient warning label and 
the impact of the nutrient warning label on behavioral 
outcomes. 
Study Design 
 
Participants will electronically acknowledge their consent to 
participate in the study. The study platform (Qualtrics) will 
randomize participants to one of the four front-of-package label 

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conditions: nutrient warning, Nutri-Score, GDA, or a no-label 
control. The participants will complete a fruit-drink selection task, 
inquiring about healthfulness of fruit drinks with each designated 
front-of-package label. After completing the fruit-drink task, the 
participant will complete a single product assessment task. After 
these, the participants will answer objective understanding and 
perceived message effectiveness questions about a breakfast cereal. 
Finally, the participants will see one product with all three label 
types and select the most discouraging label. The study will end 
with standard demographic questions. 
Subject Population 
key criteria for Inclusion 
and Exclusion: 
Inclusion Criteria 
1. 18 years old or older 
2. Currently reside in Colombia  
Exclusion Criteria 
        1. Participated in previous studies linked to this study 
Number Of Subjects  
Approximately 8,000 
Study Duration 
Each subject’s participation will last approximately 15-20 minutes. 
The entire study is expected to last 1 month. 
Study Phases 
(1) Screening: screening for eligibility and obtaining consent  
(2) Randomization: Randomly assigning participants to one of four 
conditions 
(3) Survey: Direct participants to a Qualtrics survey measuring 
product selection and perceptions and reactions to front-of-package 
labels, as well as standard demographics.  
Statistical Analysis Plan 
We will descriptively report unadjusted means (and standard 
deviations) and percentages for the primary and secondary 
outcomes. We will use linear regression for continuous outcomes 
and logistic regression for dichotomous outcomes. We will conduct 
pairwise comparisons of the predicted means to examine 
differences by all label types. We will examine whether primary 
outcomes differ by education. 
DATA AND SAFETY 
MONITORING PLAN 
Researchers will store the study data on a remote terminal server, 
and only research investigators and staff will have access to the 
data. 
 
 
 

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BACKGROUND AND RATIONALE 
Introduction 
According to the WHO, obesity and overweight are health conditions afflicting over a billion 
people worldwide. Obesity and overweight can lead to numerous health problems including 
cardiovascular disease, diabetes, musculoskeletal disorders, and various types of cancers (1). 
Colombia is not immune to this global health problem. In Colombia in 2016, more than half of 
adults were overweight and more than 22 percent of adults were obese (2). Additionally, obesity 
and overweight impact Colombian children. The Colombian Ministry of Health reports that 
approximately 18% of Colombian youth are overweight (3).  
 
As a result of this increasing health problem, the Colombian government has begun to take 
actions to address overweight and obesity in Colombia. The Colombian government (the 
Congress, the Ministry of Health) passed a law in 2021 that would require nutrient warnings on 
the front of packages high in critical nutrients to inform consumers and reduce the intake of 
these unhealthy foods and beverages (4). Similar laws have been implemented in countries 
around the world, such as Chile, Peru, and Israel (5).  
 
Research is needed to inform the design of this law. The purpose of this study is to test the 
potential effectiveness of different labels to be used on the packaging of foods and drinks to 
promote healthy diets in Colombia. This research is time sensitive and politically relevant and will 
help to inform Colombian Ministry of Health as to how product labeling will help to dissuade 
consumption and inform Colombians of product healthfulness prior to the implementation. 
STUDY OBJECTIVE  
The purpose of this study is to determine what type of front-of-package label, whether a 
Nutri-Score label, nutrient warning label, or a guideline daily amount (GDA) label 
discourage purchases of “high in” fruit drink products for adult Colombian consumers. 
 
Primary Outcomes  
o Selection of the less healthy fruit drink as the fruit drink the participant would 
rather buy. 
o Correctly identifying which fruit drink was higher in sugar. 
Secondary Outcomes  
o Perceived message effectiveness. 
o Purchase likelihood of a product in the next week if it were available. 
o Percentage of participants that correctly identify the less healthy product when 
selecting between two products. 
o Percentage of participants who correctly identify that the product contains excess 
sugar, saturated fat, or sodium. 
o Percentage of participants selecting each nutrient label as most discouraging 
them from consuming the product. 

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INVESTIGATIONAL PLAN (brief overview) 
Study Design 
The study design is a between-subjects randomized controlled trial. Qualtrics will 
randomly assign participants to one of four study arms in the Qualtrics survey. 
Participants will have an equal chance of being randomized to any of the trial arms. 
 
Study Arms: 
1. Control Arm: no warning labels 
2. Nutri-Score Label Arm: one label with a color-coded ranking A-E of the relative 
healthfulness of a product. 
3. Nutrient Warning Label: one black, octagonal warning label with the text: “Execeso de 
[azúcares; grasas saturadas; or /sal/sodio]. Minsalud” followed by the text: “Evitar Su 
Alto Consumo” 
4. Guideline Daily Amount Label Arm: five blue rectangular boxes including calories, 
total fat, saturated fat, sugar, and sodium given in kcal, g, respectively, and mg for 
sodium. Followed by the text: “De los valores diarios de referencia de nutrientes en 
una dieta de 2000 kcal.” 
 
 
In Qualtrics, participants will be asked to complete three tasks. The products presented in 
each task will have a Nutri-Score label, nutrient label, GDA label, or no labels, depending 
on which arm the participant has been randomized to.  

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As the purpose of the study is to inform Colombia’s front-of-package labeling policy, we 
set out to test front-of-package labels that have been implemented in other countries. 
Potential labeling options were determined through consultation with a food and health 
advocacy coalition in Colombia, who provided insight on which labels were most likely to 
be proposed as regulatory options in the Colombian legislature or Ministry of Health. As a 
result of these conversations, we decided to compare the GDA label (which the food 
industry has promoted), Nutri-Score label, and a no-label alternative to the nutrient 
warnings on specific outcomes related to identifying and discouraging selection of ultra-
processed foods. We hypothesized that the nutrient warnings would perform best on all 
outcomes, as previous research has found nutrient warnings to perform best on such 
outcomes (6). 
 
After completing drink/product selection task, participants will complete a Qualtrics 
survey measuring reactions to and perceptions of all three labels as well as standard 
demographics. Upon completion, participants will earn a pre-determined amount of 
points from Offerwise for completing the study. Participants are able to convert points 
into money once they accumulate a specified amount. 
 
Study Duration, Enrollment and Number of Subjects 
Participation in the study will last approximately 15-20 minutes. The entire study is 
expected to last one month. 
 
Study Population 
Inclusion Criteria 
1. 18 years old or older 
2. Currently reside in Colombia  
 
Exclusion Criteria 
1. Participation in previous studies linked to this study 
STUDY PROCEDURES (what will be done) 
Study Steps 
Participants will be recruited through Offerwise, a market research company with over 
300,000 panel participants in Colombia. If interested, panel members will complete a 
screener in Qualtrics to see if they are eligible. If they are not eligible, panel members will 
be redirected to a termination page indicating they are not eligible to participate. If they 
are eligible, panel members will be redirected to a consent form. If they agree to the 
consent form, they will acknowledge their consent by clicking an arrow to proceed to the 
study. 
 

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Following online consent, Qualtrics will equally randomize participants to one of the four 
front-of-package label conditions: nutrient warning, Nutri-Score, GDA, or a no-label 
condition. On Qualtrics, participants will complete three tasks. They will be asked to 
complete a selection task, in which participants will be asked to select which fruit drink is 
higher in sugar, which they would rather buy, and which is most unhealthy. The fruit 
drinks will be displayed with the labels corresponding to the participant’s randomly 
assigned label condition. We will only include selection tasks for one type of product due 
to survey space constraints. Following the selection tasks, the participant will be asked to 
complete a single product assessment task. They will view a prompt that reads: “The next 
questions are about food products. You will look at a few different products and answer 
questions about each one. Please keep in mind that this study seeks to evaluate your 
survey responses and not the sale of the product.” Then, they will answer a series of 
questions about the yogurt, cookies, and sliced bread, which will show the participant’s 
randomly assigned label condition. The participants will answer all questions about one 
product at a time (displayed in random order). After these, the participants will answer 
objective understanding and PME questions about the breakfast cereal. The breakfast 
cereal is always displayed last as the nutrient warning condition contains two labels. 
Finally, the participants will be randomly assigned to see the yogurt, cookies, or sliced 
bread again (one product only). However, this time, the product will not fashion a label. 
Instead, the three label types (nutrient warnings, GDA, and Nutri-Score) will be displayed 
underneath the product and the participant will be asked to select the most discouraging 
label. The study will end with standard demographic questions. 
 
Subject Completion/Withdrawal Procedures 
A study participant is determined to have completed the study when they have finished 
and exited the study survey. To withdraw their data from the study, a participant would 
have to contact the study team or the university IRB.  
 
Screen Failure Procedures 
Prior to entering into the study, individuals will complete a survey screener. If the 
individual is younger than 18 years old or does not live in Colombia, they will be deemed 
ineligible. Such participants will be redirected to a screen notifying them that they are 
ineligible for the study. 
SCREENING AND MONITORING EVALUATIONS AND MEASUREMENTS 
(how measurements will be made)  
Measurements will include results from the selection and assessment tasks as well as 
subjective responses by participants. Secondary outcomes will include a variety of 
measurements, including perceived message effectiveness, 5-point Likert scale 
questions, and identification questions. 
 
 

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Question 
Response Scale 
Primary outcomes 
 
Which of these products would you rather buy? 
1 = (image of control beverage) 
2 = (image of experimental beverage) 
Which of these products is higher in sugar? 
1 = (image of control beverage) 
2 = (image of experimental beverage) 
Secondary outcomes 
 
How much does this label... 
• 
make you concerned about the health 
consequences of consuming this product? 
• 
discourage you from wanting to eat 
consume this product? 
• 
make consuming this product seem 
unpleasant to you? 
1 = Very much 
2 = A lot 
3 = A little 
4 = Very little 
5 = Not at all 
How likely is it for you to want to purchase this 
product next week, if it were available? 
1 =Very much 
2 = A lot 
3 = A little 
4 = Very little 
5 = Not at all 
In your opinion, which of these products is most 
unhealthy? 
1 = (image of control beverage) 
2 = (image of experimental beverage) 
Do you think this product has excess [saturated 
fat/sugar/sodium]? 
1 = Yes 
0 = No 
Which of these labels would discourage you most 
from wanting to consume this product? 
[answer choices are each of the label types 
randomly displayed] 
 
STATISTICAL ANALYSIS PLAN    
Hypotheses 
Primary Outcomes 
The overall purpose of this study is to identify the impact of nutrient warnings on product 
selection and other outcomes compared to GDA labels, Nutriscore labels, and a no-label 
control, in Colombia. The primary objectives of this study are to evaluate our hypotheses 
that, compared to GDA, Nutriscore, and control, a nutrient warning label will lead to:  
 
1. Lower selection of the less healthy product in a set of two products as the product 
the consumer most wants to buy.     
2. Better ability to correctly identify which product of a set of two has higher levels of 
sugar.    
 
We will also explore whether the impact of the nutrient warning (vs. other study 
conditions) on these two primary outcomes differ by respondent’s educational level.  
 

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Secondary Outcomes 
We hypothesize that the nutrient warning label (compared to other label types) will: 
 
1. Have higher perceived message effectiveness. 
2. Be the most discouraging label. 
 
We hypothesize that the nutrient warning label (compared to all other conditions) – and 
all conditions compared to the control – will: 
 
1. Increase the ability to correctly identify the most unhealthy product when compared 
with two options. 
2. Increase the ability to correctly identify whether a single product contains excess 
sugar, saturated fat, or sodium. 
3. Lower intentions of purchasing a product high in the nutrient of concern in the next 
week if it were available.  
 
Statistical Methods 
We will use complete case analysis to handle any missing data. We will descriptively 
report unadjusted means (and standard deviations) and percentages for the primary and 
secondary outcomes. 
 
We will use a two-sided critical alpha of 0.05 to conduct all statistical tests.  
 
Sensitivity Analyses 
 
For PME, we will take the average of the 3 items for each product type if alpha>.70. For 
all outcomes assessed between-subjects only, we will then assess whether the outcomes 
vary by study arm with regression models (linear for continuous outcomes and logistic for 
dichotomous outcomes).  
 
For outcomes with multiple measurements per-person, we will fit mixed effects linear 
regression models for continuous outcomes (including PME) and a mixed effects logistic 
regression model for binary outcomes (including product selection, label selection, 
identification of healthier products), treating the intercept as random to account for 
repeated measures.  
 
We will include indicator variables for warning message (between-subjects) and product 
type (within-subjects), as well as an interaction of warning message and product type. 
We will use postestimation commands to conduct pairwise comparisons of the predicted 
means to examine differences by all label types. We will correct for multiple 
comparisons. To evaluate the most discouraging label, we examine the proportion of 
participants that selected each warning label as the most discouraging and will conduct z-

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tests to explore statistical significance of these differences. To assess whether the effect 
of the warning label on the primary outcomes differs by education, we will test for an 
interaction of warning label with low versus high education level (specified as dummy 
variables) and use a Wald chunk test to determine the joint interaction. We will use 
postestimation commands to predict means by warning label and education level and 
conduct pairwise comparisons of the predicted means.     
 
Sample Size and Power 
Using an ANOVA model in G.Power. 3.1.9.4, we estimate that with a sample of ~8,000, 
alpha of 0.05, and 80% power, we can detect an effect of f=0.037 for each of the primary 
outcomes between each arm and the control, which translates to an odds ratio of 1.14. 
 
Outliers and Exclusions 
We will exclude participants from analysis if they are duplicate responders, complete the 
study in less than two minutes, or if they do not answer at least one primary or 
secondary outcome. 
SAFETY MANAGEMENT 
Provided that this study is conducted completely online, and participants do not have any 
interactions with study staff there is no anticipation of adverse events. However, the 
investigators have provided an email to contact as well as the IRB contact information, on 
the consent form, should a participant be concerned about any aspects of the research 
study.  
DATA COLLECTION AND MANAGMENT  
Researchers will store the study data on a remote terminal server, and only research 
investigators and staff will have access to the data.  
RECRUITMENT STRATEGY 
Participants will be Offerwise participants who have voluntarily signed up to complete 
tasks remotely, including research surveys. Our study sample will include only those who 
self-enroll in the study based on interest, availability, and meeting the inclusion criteria. 
There is no specific advertisement for this study. Rather, Offerwise identifies users for the 
survey based on the inclusion criteria (age 18 or older and resides in Colombia) and 
informs them of the study opportunity. 
CONSENT PROCESS 
To provide consent, individuals will first complete a survey screener in Qualtrics. If they 
are eligible for the study, they will be redirected to the study consent form. If the 
participant agrees to the consent form, they are informed that by continuing to the 
study, they are consenting to participate. The consent process is completed entirely 
online, and at no point in the study do participants interact with the study team. 

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INFORMED CONSENT FORM 
Title: Testing product messages for Colombia  
 
Instructions (Consent form): 
We would like to invite you to take part in a brief research study to better understand 
people’s thoughts and perceptions about product messages. To join the study is 
voluntary. You may choose not to participate, or you may withdraw your consent to be in 
the study, for any reason, without penalty. This survey is open to Colombian residents 
aged 18 and over. 
 
You will complete a survey with questions about food product messages and your 
demographics.  
 
You may choose not to participate, or you may withdraw your consent to be in the study, 
for any reason, without penalty, at any time.  
 
About 8,500 people will be in this research study. You will be in the study for about 15 to 
20 minutes. This will be a one-time survey with no follow up expected. You will receive 
points through Offerwise for completion of this survey. 
 
There are no direct risks or benefits to participating that we are aware of.  
 
Privacy and Confidentiality 
We will not collect any sensitive information from you. Your responses will be linked with 
a generated participant ID, which will not be identifiable. Note that that the Offerwise 
platform is NOT meant to support participant anonymity, but your responses to this 
survey will remain confidential. Research personnel will keep data from this study on a 
password-protected  computer server and your responses will not be identifiable.  
 
Your Offerwise ID will only be collected for the purposes of distributing points and will 
not be associated with survey responses. 
 
Please only take this survey one time.   
 
If you have questions about the study, you can contact us at cepreste@live.unc.edu. If 
you have questions about your rights as a research subject, contact the UNC Institutional 
Review Board at 919-966-3113 or IRB_subjects@unc.edu.  
 
By clicking on the link to the study, you acknowledge that you have read the information 
above and agree to be in this research study. Thank you! 
 

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At the end of the survey, you will receive a code to receive credit for completing our 
study. Please enter your Qualtrics completion code in the box after you complete the 
survey so that you can receive your payment. 
 
PLANS FOR PUBLICATION 
The investigators plan to publish as an open-access peer-reviewed paper. They will target 
public health peer-reviewed journals for manuscript submission.  
 
 
 

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REFERENCES  
1. “Obesity and Overweight.” WHO, 3 March 2020. https://www.who.int/en/news-
room/fact-sheets/detail/obesity-and-overweight. Accessed 6 March 2020. 
2. Ritchie, Hannah & Roser, Max. “Obesity.” https://ourworldindata.org/obesity#what-
share-of-adults-are-obese. Accessed 6 March 2020. 
3. Colombia, Ministry of Health. “Obesidad infantil: una amenaza silenciosa.” Pamela 
Elizabeth Vallejo Figueroa, Iván Camilo, Sánchez Barrera, Jair Alberto Arciniegas Barrera, 
& Fabio Escobar Díaz, June 2019, 
https://www.minsalud.gov.co/sites/rid/Lists/BibliotecaDigital/RIDE/DE/PES/resumen-
politica-obesidad-infantil-amenaza-silenciosa.pdf.  
4. El Congreso de Colombia. Ley No 2120. 
http://www.andi.com.co/Uploads/LEY%202120%20DEL%2030%20DE%20JULIO%20DE%2
02021.pdf. Published 2021. Accessed February 15, 2023. 
5. Reyes, M., Garmendia, M.L., Olivares, S. et al. Development of the Chilean front-of-
package food warning label. BMC Public Health 19, 906 (2019). 
https://doi.org/10.1186/s12889-019-7118-1. 
6. Taillie, L.S., Hall, M.G., Popkin, B.M., Ng, S.W., Murukutla, N. Experimental studies of 
front-of-package nutrient warning labels on sugar-sweetened beverages and ultra-
processed foods: A scoping review. Nutrients 12(2), 569 (2020). 
https://doi.org/10.3390/nu12020569.