Protocol Of A Cluster Randomised Controlled Trial In Colombia-accepted Version

Background: Body dissatisfaction is highly prevalent in Latin America, including Colombia. However, culturally adapted, evidence-based interventions are lacking, although effective programs exist in Western countries. This protocol describes a cluster randomized controlled trial (cRCT) of an intervention to improve media literacy and decrease body dissatisfaction and related outcomes among adolescents in urban and rural schools in Colombia. Methods: We will recruit 1250 adolescents in 7th-10th grade (aged 11–17 years) to participate in a two-arm, cluster-randomized, open-label, controlled superiority trial in Colombia. Participating schools will be recruited by the research team. Participants will be randomized at the school level (1:1). Randomization blocks stratified by socioeconomic status (high vs. low) and geographical area (rural vs. urban) will be used to assign schools to either: (a) a school-based, four-session group intervention delivered over 2–4 weeks by trained facilitators (n = 625), or (b) a waitlist control group that will receive the intervention only after follow-up (n = 625). Participants need to be aged 11 – 17 years old, attending a participating school and class in grades 7 to 10, have written parental consent and give written assent to be eligible for participation in this study. Individuals who cannot understand spoken or written language, or who do not have parental consent to participate, will be excluded. Primary outcomes are media literacy and body dissatisfaction. Secondary outcomes include appearance comparison, thin ideal internalization, curvy ideal internalization (girls only), drive for muscularity (boys only), eating disorder symptoms, and general wellbeing. Additional exploratory outcomes include risky appearance altering behaviours (girls only), colourism and skin colour satisfaction. Furthermore, adverse outcomes will be recorded. Outcome assessments will happen pre-intervention (baseline; Timepoint 1), 1-week post-intervention (immediate post-test; Timepoint 2) and 9 – 12 months post-intervention (follow-up; Timepoint 3). Discussion: Based on pilot data, we hypothesise that the intervention group will demonstrate increased media literacy and decreased body dissatisfaction at post-test and follow-up. We also anticipate improvements in secondary outcomes. This will be the first cluster RCT to evaluate the effect of a culturally adapted body image intervention in Colombia. This trial has been registered in the ISRCTN Registry (ISRCTN15802562, https://doi.org/10.1186/ISRCTN15802562). First enrolment was on 26th of August 2025.