Healthy lifestyle interventions within the curriculum in school-age children: systematic review and meta-analysis.

Childhood obesity is a major public health challenge. Previous research has identified the impact of school-based interventions for preventing and treating obesity; we hypothesized that when curricular changes are integrated, results could be exponentiated. This study aimed to systematically review and conduct a meta-analysis of the published literature analyzing information about school-based interventions inserted in the curriculum. The Cochrane Handbook methodology was followed. An electronic search was conducted in five databases, with a specific design strategy per database. Randomized controlled trials or quasi-experimental studies of children with nutrition and physical activity (PA) interventions inserted into the school curricula were included. The risk of bias was assessed with the Risk of Bias tool. The mean differences were pooled using a fixed-effects model for the meta-analysis. The certainty of the evidence was evaluated according to the guidelines of the Grading of the Recommendations, Assessment, Development, and Evaluations working group (Protocol ID: CRD42021270557). After the screening and selection process, 12 studies were included. The interventions identified, based on the school curricula, include classroom activities and homework, among others. A meta-analysis with five intervention groups presented an overall mean difference of -0.14 body mass index (BMI) Z-score (95% CI: -0.25, -0.03) after this intervention with high certainty of the evidence. This systematic review and meta-analysis suggest that nutrition and PA lessons inserted into the curricula and supported with additional activities (i.e. homework, workshops, etc.) could increase nutrition knowledge and improve attitudes toward fruit, vegetables, and water consumption, and BMI Z-score reduction.