The Effectiveness of Linguistically Tailored Health Messages to Encourage Plant-Based Food Choices in Adolescents
试验速览
- 阶段
- 不适用
- 状态
- Enrolling By Invitation
- 入组人数
- 600
- 试验地点
- 2
- 主要终点
- Dietary behavior
研究概览
简要总结
The goal of this clinical trial is to investigate the effectiveness of linguistically tailored messages for promoting plant-based food choices in adolescents. The main question it aims to answer is:
• Are linguistically tailored messages more effective in promoting plant-based eating compared to a) non-tailored messages (active control), and b) not receiving messages at all (passive control)?
Researchers will compare participants exposed to linguistically tailored messages, non-tailored messages, and no messages to determine if linguistic messages are more effective in promoting plant-based food choices. Participants will receive daily messages promoting a plant-based diet from Monday to Friday for two weeks, accompanied by daily and weekend surveys about their food choices and message perception.
详细描述
This study is a five-arm randomized controlled trial targeting adolescents aged 11-16 years in the UK and Ireland. In the intervention arms, participants will receive daily messages promoting a plant-based diet from Monday to Friday for two weeks. The first arm serves as a passive control group, with participants receiving no messages throughout the study. In arm 2, participants will receive daily non-tailored messages for the entire two weeks. In arm 3, participants will receive linguistically tailored messages. Participants in arm 4 will receive both non-tailored and tailored messages for one week each: tailored messages in week 1 and non-tailored in week 2 (arm 4a), and non-tailored in week 1 and tailored in week 2 (arm 4b). This design supports both within-subject comparisons (tailored vs. non-tailored) and between-subject comparisons (e.g., control vs. intervention).
At the start of the program, participants will play a chat game to collect chat data for analyzing their linguistic style. These data will be used to perform a text style transfer on the intervention messages using a Large Language Model (LLM). Following this, the two-week intervention will commence with a baseline survey conducted during the first weekend. During weekdays (Monday to Friday), participants in the intervention arms (arms 2, 3, and 4) will receive daily messages promoting a plant-based diet through the research app Avicenna. Additionally, all participants, including those in the passive control group, will receive daily surveys about their lunchtime food choices. Participants in the intervention arms will also respond to questions about message perception. On the weekends following each intervention week, participants will complete comprehensive surveys (midpoint and final surveys). These surveys, along with the baseline survey, will assess all outcome measures, including dietary behaviors, determinants of behavior, perceptions of the message source, message processing, and text style characteristics.
Sample size
The expected effect size was based on two meta-analyses of online health promotion studies that included general tailoring (Krebs et al., 2010; Lustria et al., 2013). These studies reported an average effect size of 0.08 (Cohen's f) overall and 0.112 for diet-related interventions specifically. Based on an assumed effect size of 0.1 and a power of 80% for between-subjects comparisons, a sample size of 592 participants is required. Since within-subject comparisons typically yield higher statistical power, we aim for a target sample size of 600 participants (150 per arm) with complete responses.
Recruitment of participants
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- Single (Participant)
入排标准
- 年龄范围
- 11 Years 至 16 Years（Child）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Aged 11-16 years
- •Residing in the UK or Ireland
- •Having access to plant-based food options during school hours (e.g., provided by the school, purchased, or brought from home or a store)
排除标准
- •Adolescents who follow a strict vegetarian or vegan diet
结局指标
主要结局
Dietary behavior
时间窗: From the start of the intervention week (baseline survey) to the end of the intervention, after two weeks.
Participants will be asked to report their dietary behavior from the previous day. They will describe what they ate for lunch at school (open-ended question) and indicate whether the lunch was plant-based. Weekly measures will assess the frequency of plant-based meals and snacks over the past week. Participants will report how many days they consumed a plant-based breakfast, lunch, and dinner (response options: 0-7 days) and the number of plant-based snacks they had per day (response options: 0-6+ servings).
Attitude
时间窗: During the intervention at the end of week 1 and week 2.
Attitude is measured by four items value, usefulness, pleasantness and interest. Question: When you think about plant-based eating (vegetarian or vegan), how would you rate plant-based eating on... 1. Value? Response options: 1) Worthless; 2) Somewhat Worthless; 3) Somewhat Valuable; 4) Valuable 2. Usefulness? Response options: 1) Useless; 2) Somewhat Useless; 3) Somewhat Useful; 4) Useful 3. Pleasantness? Response options: 1) Unpleasant; 2) Somewhat Unpleasant; 3) Somewhat Pleasant; 4) Pleasant 4. Interest? Response options: 1) Boring; 2) Somewhat Boring; 3) Somewhat Interesting; 4) Interesting. The items will be aggregated into a single composite score.
Behavioral intention
时间窗: During the intervention at the end of week 1 and week 2.
Question: How often do you plan to eat plant-based (either vegetarian or vegan) within the next week in situations where you can freely choose? Response options: 1) Never; 2) Rarely; 3) Sometimes; 4) Often
次要结局
- Perceived Source Similarity(During the intervention at the end of week 1 and week 2.)
- Source Liking(During the intervention at the end of week 1 and week 2.)
- Source Trust(During the intervention at the end of week 1 and week 2.)
- Message Liking(During the intervention, daily (Monday-Friday) for two weeks.)
- Message Shareability(During the intervention, daily (Monday-Friday) for two weeks.)
- Perceived Message Relevance(During the intervention, daily (Monday-Friday) for two weeks.)
- Perceived Message Personalization(During the intervention at the end of week 1 and week 2.)
- Perceived Style Similarity(During the intervention at the end of week 1 and week 2.)
- Message Processing Depth(During the intervention at the end of week 1 and week 2.)
- Message Reactance(During the intervention at the end of week 1 and week 2.)
- Message involvement(During the intervention at the end of week 1 and week 2.)
研究者
David Blok
Assistant Professor
Erasmus University Rotterdam