Multi-component school intervention reduces obesity and improves health behaviors in children: a cluster- randomized...

Childhood obesity has become a global health priority due to its escalating prevalence and associated health risks. We conducted a cluster-randomized controlled trial to assess the impact of a comprehensive school-based intervention on obesity-related outcomes among primary school children in China. Eight schools (n = 400 students, 396 completed) were randomly allocated (1:1) to intervention or control groups during the 2018-2019 academic year. The 10-month intervention incorporated a structured health education curriculum, enhanced physical activity sessions, periodic body mass index (BMI) monitoring with personalized feedback, and family engagement activities as its core components.  The primary outcome was change in BMI. While secondary outcomes encompassed obesity prevalence, body composition, dietary behaviors, physical activity, and health knowledge. The analysis revealed significantly greater reduction in BMI in the intervention group compared to controls (mean difference: -0.36 kg/m²; 95% CI: -0.58 to -0.13; P = 0.002). Subgroup analyses revealed differential effects by sex, father's educational level, overweight or obesity at baseline, and main caregivers (parents) (all P < 0.05), whereas, no evidence of difference across the main caregivers (non-parents) and the mother's education level (above high school). Obesity prevalence decreased by 3.54% in the intervention versus 0.51% in control schools (OR = 0.34, 95% CI: 0.25 to 0.45; P = 0.020). Significant improvements were noted in obesity-related knowledge, dietary habits, moderate-to-vigorous physical activity (MVPA), and reduced sedentary time (all P < 0.05), though fitness measures showed no significant between-group differences. Overall, these findings demonstrated that a well-designed school-based program can effectively mitigate obesity risk and promote healthier behaviors among children. Further research should examine long-term sustainability and scalability across diverse settings.