Abstract 17944: Effects of School-Based Interventions on Body Mass Index in Children and Adolescents: a Systematic Overview and Meta-analysis

Background: Childhood obesity is a major public health threat. Various school-based interventions (SBIs) to prevent obesity through physical activity and/or dietary modifications were implemented. However, the effectiveness of such SBIs remains unproven. Therefore, we conducted a meta-analysis of randomized controlled trials (RCTs) of SBIs. Methods: We searched for RCTs of SBIs published since 1990. To be eligible studies had to have an RCT design, to include children aged 6-18 years and SBIs were defined as non-pharmacological and non-surgical interventions carried out in a school setting with a minimum duration of 12 weeks. The primary outcome was change in body mass index (BMI. For each study the difference in the mean change in BMI between the intervention and the control groups was computed. The summary estimate for the difference in mean change in BMI and the 95% confidence interval (CI) was computed using a weighted inverse variance approach and a random- effects model. The I 2 statistic was used to test for heterogeneity. Results: Of 504 studies identified, 41 involving 42 430 participants met the inclusion criteria. SBIs varied greatly between studies by type, duration and delivery. In 10 RCTs the SBI focused on physical activity, in 6 on dietary modifications and in 25 on both physical activity and dietary modifications. SBIs duration ranged from 12 weeks to 4 years. There was no significant difference in mean BMI change between the intervention and the control groups (mean difference = -0.281kg/m 2 ; 95% CI -0.584 to 0.022), although there was significant heterogeneity between the RCTs’ findings (Figure). We found also no consistent impact on other measures of adiposity, physical activity patterns, dietary intakes and psychosocial health and wellbeing. Conclusions: SBIs had no substantial impact on BMI in children aged 6-18 years. Further research is needed to identify effective interventions to prevent childhood obesity.