The goal of this randomized controlled trial is to evaluate the impact of health information labeling on alcohol-related knowledge and behaviors in adults purchasing alcohol in Barcelona, Spain. The main questions it aims to answer are: * Does a label containing a cancer message have a larger impact on knowledge, behavior, intentions, risk perception, emotional response, product appeal and policy support compared to a responsibility label? * Does the positioning of the label (front vs. back) on the alcohol container affect these outcomes? Researchers will compare the impact of cancer message labels vs. responsibility labels and front vs. back positioning to see if there are differences in the primary outcome (knowledge of alcohol causing cancer) and secondary outcomes (behavior, intentions, risk perception, emotional response, and policy support). Additionally, the study will provide insight in whether there is a testing effect of primary outcome pre-measurement by exposing only half of the sample to baseline question on knowledge of alcohol related harms. Participants will: * Be recruited in front of selected supermarkets in Barcelona after purchasing alcohol for their own consumption. * Complete a baseline questionnaire. * Receive a sticker containing a randomly assigned health message that will be applied to every alcohol beverage they have purchased. * Receive an invitation to complete two follow-up surveys, one a week and one a month after the intervention.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
1,410
A sticker with health information on alcohol causing cancer is applied to alcoholic beverage containers purchased by the participants.
A sticker with a message to drink responsibly will be applied to alcoholic beverage containers purchased by the participants.
A sticker will be applied to the front of the alcoholic beverage containers purchased by the participants.
A sticker will be applied to the back of the alcoholic beverage containers purchased by the participants.
Primary outcome (knowledge of alcohol related harms) is tested at baseline.
Primary outcome (knowledge of alcohol related harms) is not tested at baseline.
Sampled supermarkets in selected city neighbourhoods
Barcelona, Spain
Knowledge of alcohol causing cancer
Knowledge will be assessed with the question "Which of the following diseases and conditions does alcohol consumption increase the risk of? (select all that apply)", with the possible choices being "Cancer", "Heart disease", "Respiratory disease", "Alcohol Use Disorder", "Injuries", "Diabetes" and "Liver disease" displayed randomly, and "I don't know" and "None" as exclusive options. If participants select "Cancer" as an outcome, a follow up question will ask: "Which of the following cancers do you think drinking alcohol increases the risk of? (select all that apply)", with "Female breast cancer", "Liver cancer", "Colon cancer", "Skin cancer", "Oral cancer", displayed randomly, and "I don't know" and "None" as exclusive options. The outcome will be dichotomous based on whether the participants correctly identify the link between alcohol and two cancers mentioned in the label: breast and colon cancer.
Time frame: 1 week / 1 month
Alcohol consumption behaviour
Decrease in alcohol consumption will be measured with measuring the amount of standard drinks consumed in the last 7 days ("How many standard drinks of alcohol did you drink over the last 7 days?"), as well as based on question on whether they have foregone an alcoholic drink because they wanted to drink less (In the last 7 days, did you ever forego an alcoholic drink because you wanted to drink less? Yes/No).
Time frame: 1 week / 1 month
Risk perception
Perceived personal cancer risk will be measured with question "If I consume alcohol on a regular basis, I am at greater risk of getting cancer." Perceived general health risk will be measured with question "If I consume more alcohol, I am at greater risk for health harm". Both questions will be measured on 5-point Likert scale (strongly Disagree to Strongly Agree).
Time frame: 1 week / 1 month
Behavioural intention
Behavioural intention to decrease alcohol consumption will be measured with the question "I intend to cut down on the number of alcohol units that I drink in the forthcoming month" on 5-point Likert scale (Strongly Disagree to Strongly Agree), only at both follow-ups.
Time frame: 1 week / 1 month
Emotional response to the labels
Emotional response to the labels will only be measured among those reporting to have noticed the labels: "Thinking about the labels on the alcohol containers I've seen as part of this study, I felt: disgusted / afraid / uncomfortable / worried" / excited / pleased" With Likert answers scale from 1 to 5 (1 = "not at all", 3 = "moderately", and 5 = "very").
Time frame: 1 week
Support for alcohol policies
Support for alcohol policies will be measured with listing range of alcohol policies (e.g. increasing the price of alcohol, reducing the number of outlets that sell alcohol" and asking the participants "To what extent would you support the government in your country introducing the following alcohol-related policies? Please indicate your answer on the scale below from 1 (strongly disagree) to 5 (strongly agree).
Time frame: 1 week / 1 month
Product appeal
It will only be measured among those reporting to have noticed the labels, with three items developed for this study ("I found the beverages less appealing after noticing the health information on the labels"; "The health information on the labels reduced my enjoyment of these beverages"; "I felt the health information on the label detracted from the overall alcohol product appearance") on 5-point Likert scale (Strongly Disagree to Strongly Agree).
Time frame: 1 week
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