A meta-analysis of school-based obesity prevention programs demonstrates limited efficacy of decreasing childhood obesity.

Childhood obesity is a global concern. The objectives of this meta-analytical study were to evaluate the effectiveness of school-based childhood obesity prevention programs, and to examine program components (moderators). The methods included searching databases (PubMed, Google Scholar, and the university's EBSCOhost Web service) as well as handsearching reference lists of articles published in English. Selection criteria for studies to be included in the meta-analysis were limited to studies that reported body mass index (BMI) or skinfold thickness as outcome measures and were school-based obesity prevention interventions; cross-sectional design studies were excluded. We hypothesized the meta-analysis would yield a summary effect size of magnitude which would indicate that school-based interventions have been effective in improving children's BMI or skinfold thickness values. A total of 26 114 children from 27 school-based childhood obesity prevention programs provided 54 effect sizes. A random-effects model calculated a small summary effect size of 0.039 (95% confidence interval -0.013 to 0.092). Heterogeneity among studies was observed which disappeared after pooling studies that used a randomized controlled trial design with one program moderator (physical activity or nutrition). We failed to accept our hypothesis and concluded that overall, school-based interventions have not been effective for improving body mass index or skinfold thickness to curb childhood obesity; however, randomized controlled trials that focused on physical activity or nutrition appeared to produce promising results.