Clinical trial NCT03511937: Impact of Sugar-Sweetened Beverage Health Warnings
Official title: A Randomized Controlled Trial Evaluating the Impact of Sugar-Sweetened Beverage Health Warnings on Purchases
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Dietary Habits
Keywords: Food and beverage purchases
Sugar-sweetened beverages
Beverages
Lead sponsor: University of North Carolina, Chapel Hill
Sponsor class: OTHER
Collaborators: name: North Carolina Translational and Clinical Sciences Institute
First posted: 2018-04-30
Enrollment: 400
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: Consumption of sugar-sweetened beverages (SSBs) like sodas, sports drinks, and fruit drinks remains a pressing public health concern in the United States. Consumption of SSBs remains well above recommended levels, and has been linked to obesity, diabetes, and cardiovascular disease. In response, policymakers across the U.S. have proposed requiring warning messages on SSB containers to inform the public and reduce consumption to healthier levels. While online studies find that such warnings reduce intentions to purchase SSBs, no studies have yet examined the impact of warnings on actual consumer behavior. The purpose of this randomized trial is to determine whether health warnings on sugar-sweetened beverages are more effective than control labels at reducing purchases of sugar-sweetened beverages. The trial will take place in a mock convenience store. Participants will be randomly assigned to a health warnings arm in which all sugar-sweetened beverages in the store are labeled with a health warning, or to a control arm in which all sugar-sweetened beverages in the store are labeled with a neutral label. Participants will select items to purchase with cash, and purchases will be compared across trial arms.

Detailed description: Background: Obesity, diabetes and cardiovascular disease are among the leading causes of death in the United States. Consumption of sugar-sweetened beverages (SSBs) such as sodas, fruit drinks and sports drinks increases risk of these preventable conditions. SSBs are particularly problematic because they are high in calories but offer little nutritional value, and because the liquid calories in SSBs cause faster spikes in blood sugar and lower feelings of fullness than solid foods.

Despite these risks, the average American adult consumes more than 130 calories per day from SSBs, well above recommended levels. A promising strategy for reducing SSB consumption is requiring health warnings on SSB containers. Online studies show that health warnings attract consumers' attention and reduce intentions to purchase SSBs. However, no research has tested the impact of SSB health warnings on actual behaviors. This randomized trial evaluates whether health warnings reduce purchases of SSBs.

Setting: The trial will take place a mock convenience store setting created for researchers to examine how store and product characteristics influence consumer purchases in a controlled but realistic environment. The store reflects a convenience store's characteristics, selling foods, beverages, and household items at real-world prices. Participants can buy these products using cash.

Recruitment: Participants will be recruited via university community subject pools, printed flyers posted, and online listings. Interested potential participants will complete an online pre-enrollment screening questionnaire to determine their eligibility. If eligible, they will be invited to schedule a time to visit the mock store for the trial.

Informed consent: At the beginning of the study visit, research staff will review the consent documents with the participants. After reviewing the form, the research staff member will ask the participant if he or she has any questions. Then both parties will sign the consent form and the participant will receive a copy of the consent form to keep.

Randomization: Participants will be randomly assigned to trial arms. An independent biostatistician will conduct the randomization a priori. Participants will have an equal chance of being randomized to either arm of the trial. Randomization will be carried out by generating a random number for each participant identification code (ID). Participant IDs will be ordered on this random number from smallest to largest. The bottom half of the IDs will be assigned to the control arm and the top half to the treatment arm (trial arms are described below). When participants arrive for their study visit, they will be assigned the next consecutive participant ID and will be allocated to the trial arm previously assigned to that ID.

Experimental Procedures: When participants arrive at the mock store, they will be provided with a shopping basket and their participation incentive in cash. Participants will be instructed to pretend they are on a usual shopping trip and reminded that there are no right or wrong products to select. They will not be told the trial's purpose.

Participants will be asked to complete a shopping task. They will be given a list of product categories and asked to select their preferred products in each of these categories. They will indicate their selections by placing products in their shopping basket. Before they begin the shopping task, participants will be instructed that they will be required to purchase one of the items they select, and that this item will be chosen for them at random by the experimenter. This procedure incentivizes participants to only select products they are actually interested in purchasing. After participants have completed the shopping task, the experimenter will randomly choose one of the products in the participant's basket for participant to purchase with his or her incentive cash. The participant will pay for the product and will receive change as necessary. After paying for their item, participants will complete a computer-based survey in another room.

Assessment: The products participants select will be recorded by the experimenter at the end of the shopping task. Participants will also complete 1 computer-based survey immediately after completing the shopping task.

Detailed description of the trial arms: Participants will be assigned to either a health warnings arm or a control arm. In the health warnings arm, all SSB products will be labeled with a health warning label. Investigators developed the text and design of these labels based on previous research and on label designs described in US and international legislation. In the control arm, all SSB products will be labeled with a neutral label, also developed by the investigators. In both arms, labels will be adhered directly on the front-of-package of SSB containers.

Eligibility criteria: Inclusion Criteria:

* Age 18 years or older
* Consume at least 12oz/week of sugar-sweetened beverages during the past month
* Be able to read and speak English

Exclusion Criteria:

* Under the age of 18 years
* Consume less than 12 ounces/week of sugar-sweetened beverages during the past month
* Unable to read or speak English

Primary outcomes:
measure: Mean Number of Calories (kcal) Purchased From Sugar-sweetened Beverages
timeFrame: At completion of ~10-minute shopping task
Secondary outcomes:
measure: Mean Number of Calories (kcal) Purchased From All Foods and Beverages
timeFrame: At completion of ~10-minute shopping task
measure: Percent of Participants Who Purchase a Sugar-sweetened Beverage
timeFrame: At completion of ~10-minute shopping task
measure: Mean Number of Sugar-sweetened Beverages Purchased
timeFrame: At completion of ~10 minute shopping task
measure: Mean Intentions Score to Limit Consumption of Beverages Added Sugar
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Intentions Sore to Limit Consumption of Specific Sugar-sweetened Beverages
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Percent of Participants Who Notice the Trial Labels
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Attention Score to the Trial Labels
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Emotional Reactions Score to Trial Labels
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Cognitive Elaboration Score
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Social Interactions About the Labels
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Perceptions of Added Sugar Score Content in Specific Sugar-sweetened Beverages
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Attitudes Score Toward Consuming Specific Sugar-sweetened Beverages
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Product Attitudes Score Toward Specific Sugar-sweetened Beverages
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Outcome Expectations Score Regarding Consumption of Beverages With Added Sugar
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
Other outcomes:
measure: Mean Injunctive Norms Score Regarding Consumption of Beverages With Added Sugar
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Perceived Message Effectiveness of Trial Label
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Support for Sugar-sweetened Beverage Health Warning Labels Score
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Self-efficacy to Limit Consumption of Beverages With Added Sugar Score
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
measure: Mean Response Efficacy of Limiting Consumption of Beverages With Added Sugar Score
timeFrame: Within 30 minutes following completion of ~10-minute shopping task
Locations:
city: Chapel Hill
country: United States
facility: University of North Carolina Chapel Hill
state: North Carolina
Study officials:
affiliation: University of North Carolina, Chapel Hill
name: Anna H Grummon, MSPH
role: PRINCIPAL_INVESTIGATOR
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