JMIR Publications

ABSTRACT

Background:

InCharge is a newly developed school-based health intervention aimed at older adolescents, and aims to promote a healthier lifestyle through increasing self-regulation skills. After the program´s effectiveness was previously investigated in a pilot study, the content of the InCharge program was adapted. This study describes the protocol of the cluster randomized controlled trial, which aims to investigate the effectiveness of the InCharge program. Methods/Design: A cluster randomized controlled trial including 70 classes with late adolescents (aged 16 and older) in the Netherlands will be conducted to test the effectiveness of the InCharge program. After schools are recruited, randomization occurs at the class level. The trial consists of two conditions: an experimental condition and a control condition. Participants in the experimental condition will be given the InCharge intervention, consisting of four lessons of 50 minutes, each lesson containing three assignments of approximately 15 minutes. While participants in the experimental condition receive InCharge, participants in the control condition are taught regular academic school courses. Surveys are administered one week before the intervention (baseline), one week after the intervention (posttest), and twelve weeks after the intervention (follow-up). Variables of interest include, but are not limited to, self-regulation, (predictors of) snack intake, physical activity, and alcohol use, and interpersonal communication about these health behaviors. In addition to surveys, observations will be conducted during the first and fourth lesson, teachers will be interviewed, and focus groups will be held with a selection of students from the intervention condition. Discussion: In this study protocol, the design of a cluster randomized controlled trial is described, which assesses how effectively the school-based intervention InCharge stimulates healthier lifestyles among late adolescents. We hypothesize that participants in the experimental condition will consume less alcohol, eat fewer unhealthy snacks, and be more physically active compared to students in the control condition. Trial registration: The protocol for this study is registered with the Netherlands Trial Register NTR6888.