A micro-randomized trial of JITAI messaging to improve adherence to multiple weight loss behaviors in young adults

项目摘要 据估计，到2030年，每2名美国成年人中就有1人患有肥胖症，肥胖症是导致发病率和死亡率的主要原因。这个 体重增加的风险最高的是18-35岁的年轻人。面对面的行为干预 通常会产生临床上显著的体重减轻，但成本和伸展范围的减少限制了它们的影响能力 人口层面的肥胖症。基于网络的干预，模仿每周面对面的结构 治疗已被证明是一种可行的替代方案，尽管体重减轻通常比亲自治疗要小 治疗。移动处理有可能达到较高的覆盖范围，但效果较差，可生产1-3公斤 超过6个月。称为“即时适应性干预”(JITAIS)的较新数字干预方法 承诺通过提供适应性、个性化的行为反馈来改善移动结果， 包括在“正确的时间”而不是在固定的时间表上提供“正确类型的支持”。这个“就在- 低成本和广泛可用的数字健康工具的出现使时间或JIT方法成为可能 这使得能够收集不断更新的健康数据。然而，到目前为止，还没有JITAI成功 有针对性的多种与体重相关的行为(体重、活动和饮食)，而且还没有系统的 检查哪些类型的消息传递干预最能促进对这三种减肥的坚持 行为，它们对谁有效，在什么条件下。为了解决这个问题，我们将使用 评估7种针对特定行为的干预信息效果的微随机试验 在实现日常行为目标的JIT时刻中提供的变更技术(即BCT消息) 在201名超重和肥胖的青壮年中。所有参与者都将获得为期6个月的行为 使用我们的轻推移动应用程序进行减肥干预，其中包括基于证据的每周课程，量身定做 反馈、自我监控和日常BCT消息。参与者将收到一个无线秤，活动跟踪器， 在应用程序中跟踪红色食物(高卡路里食物)，并有3个目标：每天称体重，每天活动分钟的目标 如果达到这个标准，这个数字就会逐渐增加，而且每天的红色食物也会受到限制。在每天3个决策点，参与者将被 微随机化接收或不接收7种类型的BCT消息中的1种。每条干预消息都有 唯一的可用性决策规则。已仔细选择候选干预消息选项 来自经验证据，在我们之前的研究中进行了测试，或者来自我们的试点微随机试验。评估 每天发生，在0、3和6个月时，以实现以下具体目标：1)评估 关于日常坚持减肥行为的每个行为改变技术信息(即BCT信息)；2) 确定BCT消息对近期结局的影响是否随时间变化；以及3)评估 BCT信息对近期结果的影响是否受到参与者的背景因素的影响。 研究结果将指导如何将适应性、行为和上下文相关的消息合并到 未来的JITAI是为了减肥。

PROJECT ABSTRACT An estimated 1 in 2 US adults will have obesity by 2030, which is a major cause of morbidity and mortality. The highest risk of weight gain is among young adults ages 18-35 years. In-person behavioral interventions generally produce clinically significant weight losses, but cost and reduced reach limit their ability to impact obesity at a population level. Web-based interventions that mimic the structure of weekly face-to-face treatment have proven a viable alternative, though weight losses are generally smaller than in-person treatment. Mobile treatments have the potential for high reach, but have been less effective, producing 1-3 kgs over 6 months. Newer digital intervention approaches called “just-in-time adaptive interventions” (JITAIs) promise to improve upon mobile outcomes by offering adaptive, personalized feedback on behavior, which consists of providing the “right type of support” at “the right time” rather than on a fixed schedule. This “just-in- time,” or JIT, approach is made possible by the emergence of low-cost and widely available digital health tools that allow for the collection of continually updated health data. However, to date, no JITAIs have successfully targeted multiple weight-related behaviors (weighing, activity, and diet), and there has been no systematic examination of what types of messaging interventions best promote adherence to these three weight loss behaviors, for whom they are effective, and under what conditions. To address this problem, we will use a micro-randomized trial to evaluate the effects of 7 types of intervention messages targeting specific behavior change techniques (i.e., BCT messages) delivered in JIT moments on daily achievement of behavioral goals among n=201 young adults with overweight and obesity. All participants will receive a 6-month behavioral weight loss intervention using our Nudge mobile app, which includes evidence-based weekly lessons, tailored feedback, self-monitoring, and daily BCT messages. Participants will receive a wireless scale, activity tracker, and track “red” foods (high-calorie foods) in the app and have 3 goals: weigh daily, a daily active minutes goal that gradually increases if met, and a daily red foods limit. At 3 decision points per day, participants will be micro-randomized to receive or not receive 1 of 7 types of BCT messages. Each intervention message has unique decision rules for availability. Candidate intervention message options have been carefully selected from empirical evidence, tested in our prior studies, or are from our pilot micro-randomized trial. Assessments will occur daily, and at 0, 3 and 6 months, to accomplish the following specific aims: 1) Evaluate the effects of each behavior change technique message (i.e., BCT message) on daily adherence to weight loss behaviors; 2) Determine whether the effects of BCT messages on proximal outcomes change over time; and 3) Assess whether the effects of BCT messages on proximal outcomes are moderated by participants’ contextual factors. Findings will guide how adaptive, behaviorally- and contextually-dependent messages are incorporated into future JITAIs for weight loss.