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，这是发病率和死亡率的主要原因。的 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 通常产生临床上显著的体重减轻，但成本和范围缩小限制了它们的影响能力， 肥胖在人口水平上。基于网络的干预措施，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，尽管体重减轻通常小于人 治疗移动的处理具有高覆盖率的潜力，但效果不太好，仅产生1-3公斤 超过6个月。新的数字干预方法，称为“及时适应性干预”（JITAIs） 承诺通过提供自适应、个性化的行为反馈来改善移动的结果，这 在“正确的时间”而不是按照固定的时间表提供“正确类型的支持”。这个“刚- 低成本和广泛使用的数字健康工具的出现使“时间”或JIT方法成为可能 允许收集不断更新的健康数据。然而，迄今为止，没有一个JITAI成功地 针对多种与体重相关的行为（体重，活动和饮食），并且没有系统的 检查什么类型的信息干预最能促进坚持这三种减肥方法 行为，对谁有效，在什么条件下有效。为了解决这个问题，我们将使用 一项评估针对特定行为的7种干预信息效果的微观随机试验 改变技术（即，BCT消息）在JIT时刻交付，以实现日常行为目标 在n=201名超重和肥胖的年轻成人中。所有参与者将接受为期6个月的行为 使用我们的Nudge移动的应用程序进行减肥干预，其中包括基于证据的每周课程， 反馈、自我监测和每日BCT信息。参与者将获得一个无线秤，活动跟踪器， 并在应用程序中跟踪“红色”食物（高热量食物），并有3个目标：每日体重，每日活动分钟目标 如果达到标准，会逐渐增加，每天的红色食物限制。在每天3个决策点，参与者将 微随机化以接收或不接收7种类型的BCT消息中的1种。每个干预消息都有 独特的可用性决策规则。候选干预消息选项经过精心挑选 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观随机试验。评估 将每天进行，并在0、3和6个月时进行，以实现以下特定目标：1）评价 每个行为改变技术消息（即，BCT消息）关于每天坚持减肥行为; 2） 确定BCT信息对近端结局的影响是否随时间变化;以及3）评估 BCT信息对近端结果的影响是否受到参与者的背景因素的调节。 研究结果将指导如何适应，行为和上下文相关的信息被纳入 未来的吉泰减肥药

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.