Impact of a participatory research intervention based on a citizen science approach on snacking consumption in European adolescents from deprived areas: a cluster randomised control trial of the SEEDS project

Improving adolescent diets requires promising interventions, best developed through participatory research like Citizen Science (CS). The present study aimed to assess the impact of a CS intervention on the consumption of healthy and unhealthy snacking choices for adolescents living in deprived areas and the influence of gender, age, and socioeconomic status (SES) in snacking behaviour. SEEDS is a cluster-randomised controlled trial (c-RCT) in four European countries, with 26 high schools randomized to intervention (IG) or control (CG) groups. The analysis included 1,208 adolescents aged 13–15 (IG = 589, CG = 619). Adolescents from IG in each country co-created a 6-month intervention on healthy snacking and physical activity. Snack consumption was the main outcome, assessed via the Health Behaviour in School-Aged Children questionnaire. General Linear Models analysed intervention impact and the influence of gender, sex, and SES. IG adolescents showed higher odds than CG of daily fruit consumption [OR (95% CI) = 1.44 (0.03–2.02)], daily water consumption [OR (95% CI) = 1.89 (1.30 -2.77)] during school, and daily vegetable consumption [OR (95% CI) = 1.36 (1.01–1.82)] outside school hours. IG adolescents showed a higher odds of occasional cake/biscuits consumption [OR (95 CI) = 1.55 (1.14–2.13); OR (95% CI) = 1.82 (1.39–2.39)] and occasional juices/smoothies’ consumption [OR (95 CI) = 1.57 (1.15–2.16); OR (95% CI) = 1.33 (1.03–1.71)] than CG during and outside school. No effects were found for other snacks. A CS intervention, co-created by adolescents, improved snacking in and out of school, though promoting healthy snacking remains challenging and should be a focus for future efforts. ClinicalTrials.gov Identifier: NCT05002049 (URL: https://clinicaltrials.gov/study/NCT05002049?cond=NCT05002049&rank=1); Date of registration: July 15, 2021.