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Outcomes of a pilot microrandomized trial of just-in-time adaptive intervention messages nudging weight-related behaviors in young adults
Valle, C. G., Nezami, B. T., O'Shea, N. G., Hatley, K. E., & Tate, D. F. (2025). Outcomes of a pilot microrandomized trial of just-in-time adaptive intervention messages nudging weight-related behaviors in young adults. Digital Health, 11, 20552076251353267. Advance online publication. https://doi.org/10.1177/20552076251353267
OBJECTIVE: There is limited evidence on the effects of various types of intervention messages on achievement of daily behavioral goals in mobile weight loss programs. Nudge, a 12-week pilot microrandomized trial among young adults, tested whether 7 types of intervention messages based on behavior change techniques (BCTs) increased the likelihood of daily goal achievement.
METHODS: Participants received lessons, tailored feedback, self-monitoring tools, and daily messages, and had daily behavioral goals (weighing, active minutes goal, and red foods limit). Four times/day, participants (N = 52, aged 18-35, body mass index 25-40 kg/m2) were randomized to receive or not receive 1 of 7 types of BCT-based messages. Generalized estimating equations evaluated the effects of receiving a message versus not on daily goal achievement, and of receiving and viewing a message versus not viewing a message.
RESULTS: Randomization to receive any message (vs. none) did not impact likelihood of meeting daily goals overall but was associated with fewer red foods tracked (odds ratio (OR) = .96; 95% confidence interval (CI): .94-.98). Randomization to receive (vs. not receive) a social comparison message about red foods was associated with fewer red foods tracked (OR = .92; 95% CI: .85-.99); no other message types were associated with daily goal achievement. Receiving and viewing any message (vs. not viewing) increased odds of achieving daily goals for all 3 behaviors: weighing (OR = 1.91; 95% CI: 1.06-3.43), active minutes (OR = 1.63; 95% CI:1.20-2.20), and red foods limit (OR = 2.09; 95% CI:1.46-3.01).
CONCLUSIONS: BCT-based messages may nudge achievement of daily goals when participants view them. Further research should explore how to increase and maintain engagement in mobile behavioral interventions.
TRIAL REGISTRATION: Precision Public Health: Enhancing Connections to Develop Just-in-Time Adaptive Intervention Strategies (Nudge); https://clinicaltrials.gov/study/NCT03836391; ClinicalTrials.gov ID: NCT03836391.
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