Physical activity, diet and other behavioural interventions for improving cognition and school achievement in children and adolescents with obesity or overweight

Objective: To assess whether healthy weight interventions improve school achievement, cognitive function and/or future success in children and adolescents with obesity or overweight, compared with standard care, waiting-list control, no treatment, or an attention placebo control group.
Methods: In February 2017, we searched CENTRAL, MEDLINE and 15 other databases, searched two trials registries, reference lists, and handsearched one journal from inception. We included randomised and quasi-randomised controlled trials of behavioural interventions for weight management in children and adolescents with obesity or overweight. Four review authors independently selected studies for inclusion. Two review authors extracted data, assessed quality and risks of bias, and evaluated the quality of the evidence using the GRADE approach. We used data analysis procedures expected by the Cochrane Collaboration.
Results: We included 18 studies of which eight studies were physical activity-only interventions, seven studies combined physical activity programmes with healthy lifestyle education, and three studies delivered dietary interventions. The number of studies included for each outcome was low, with up to only three studies per outcome. The quality of evidence ranged from high to very low and 17 studies had a high risk of bias for at least one item. Compared to standard practice, analyses of physical activity-only interventions suggested high-quality evidence for improved mean cognitive executive function scores (MD 5.00, 95%CI 0.68-9.32). There was a moderate difference in the average achievement across subjects taught at school favouring interventions targeting the improvement of the school food environment compared to standard practice in adolescents with obesity (SMD 0.46, 95%CI 0.25-0.66), but not with overweight. There was no evidence of a beneficial effect of physical activity-only and physical activity interventions combined with healthy lifestyle education on average achievement across subjects taught at school,mathematics achievement, reading achievement or inhibition control.
Conclusions: School and community-based physical activity interventions can benefit executive functions of children with obesity or overweight specifically. Similarly, school-based dietary interventions may benefit general school achievement in children with obesity. Future obesity treatment and prevention studies in clinical, school and community settings should consider assessing academic and cognitive as well as physical outcomes.