Abstract
<sec> <title>BACKGROUND</title> <p>Youth vaping remains alarmingly prevalent and represents a growing public health challenge worldwide. Despite growing attention, the effectiveness of scalable prevention strategies remains uncertain. As adolescents are increasingly immersed in digital environments, innovative, interactive interventions are needed to engage them and influence health behaviours.</p> </sec> <sec> <title>OBJECTIVE</title> <p>This study aimed to assess the effect of a theory-driven digital game-based learning intervention (VapGaMo) in preventing vaping intention among adolescents.</p> </sec> <sec> <title>METHODS</title> <p>A two-arm parallel cluster randomized controlled trial was conducted among 13- to 15-year-old Malaysian early adolescents. Schools were randomly assigned (1:1) to VapGaMo (a single 90-minute, facilitator led videogame grounded in the Theory of Planned Behavior) or control group (attention-matched online flash game). Outcomes were assessed at baseline, post-intervention, and 3 months follow-up. The primary outcome was vaping intention at 3 months; secondary outcomes included knowledge, attitudes, subjective norms, and perceived behavioural control. Intention-to-treat analyses were performed using generalized estimating equations, with clustering of participants within schools appropriately accounted for.</p> </sec> <sec> <title>RESULTS</title> <p>A total of eight schools (n = 370 students) completed the baseline assessment, with equal allocation to the intervention and control groups (4 schools and 185 students per arm). Compared with the control group, students in the intervention group showed a significant reduction in vaping intention (β = −0.28 [95% CI −0.47 to −0.08], p = 0.004) and a significant improvement in vaping-related knowledge (β = 1.52 [95% CI 0.75, 2.28], p < 0.001) at the 3-month follow-up. Immediate post-intervention improvements were also observed in attitudes towards vaping and perceived behavioral control.</p> </sec> <sec> <title>CONCLUSIONS</title> <p>Digital game-based learning intervention (VapGaMo) effectively reduced vaping intention, improved vaping-related knowledge, changing attitude and perceived behavioral control. These findings support the potential of the innovative theory-driven, game-based interventions as scalable and engaging approaches for adolescent vaping prevention.</p> </sec> <sec> <title>CLINICALTRIAL</title> <p>thaiclinicaltrials.org (TCTR20241222001)</p> </sec> <sec> <title>INTERNATIONAL REGISTERED REPORT</title> <p>RR2-doi.org/10.1136/bmjopen-2025-110419</p> </sec>