Behavioral Interventions to Prevent Childhood Obesity: A Systematic Review and Metaanalyses of Randomized Trials

CONTEXT: The efficacy of lifestyle interventions to encourage healthy lifestyle behaviors to prevent pediatric obesity remains unclear. OBJECTIVE: Our objective was to summarize evidence on the efficacy of interventions aimed at changing lifestyle behaviors (increased physical activity, decreased sedentary activity, increased healthy dietary habits, and decreased unhealthy dietary habits) to prevent obesity. DATA SOURCES: Data sources included librarian-designed searches of nine electronic databases, references from included studies and reviews (from inception until February 2006), and content expert recommendations. STUDY SELECTION: Eligible studies were randomized trials enrolling children and adolescents assessing the impact of interventions on both lifestyle behaviors and body mass index (BMI). DATA EXTRACTION: Two reviewers independently abstracted data on methodological quality, study characteristics, intervention components, and treatment effects. DATA ANALYSIS: We conducted random-effects metaanalyses, quantified inconsistency using I(2), and conducted planned subgroup analyses for each examined outcome. DATA SYNTHESIS: Regarding target behaviors, the pooled effect size for physical activity (22 comparisons; n = 9891 participants) was 0.12 95% confidence interval (CI) = 0.04-0.20; I(2) = 63%, for sedentary activity (14 comparisons; n = 3003) was -0.29, (CI = -0.35 to -0.22; I(2) = 0%), for healthy dietary habits (14 comparisons, n = 5468) was 0.00 (CI = -0.20; 0.20; I(2) = 83%), and for unhealthy dietary habits (23 comparisons, n = 9578) was -0.20 (CI = -0.31 to -0.09; I(2) = 34%). The effect of these interventions on BMI (43 comparisons, n = 32,003) was trivial (-0.02; CI = -0.06-0.02; I(2) = 17%) compared with control. Trials with interventions lasting more than 6 months (vs. shorter trials) and trials with postintervention outcomes (vs. in-treatment outcomes) yielded marginally larger effects. CONCLUSION: Pediatric obesity prevention programs caused small changes in target behaviors and no significant effect on BMI compared with control. Trials evaluating promising interventions applied over a long period, using responsive outcomes, with longer measurement timeframes are urgently needed.