The effectiveness of pediatric obesity prevention policies: a comprehensive systematic review and dose-response meta-analysis of controlled clinical trials

Background Childhood obesity persists as a serious public health problem. In the current meta-analysis, we summarized the results of controlled trials that evaluated the effect of obesity prevention policies in children and adolescents. Methods Three databases (SCOPUS, PubMed and Embase) were searched for studies published before the 6th April 2020, by reported outcome measures of body mass index (BMI) and BMI-Z(score). Forty-seven studies reported BMI, while 45 studies reported BMI-Z(score) as final outcome. Results The results showed that the obesity-prevention policies had significant effect in reducing BMI (WMD: - 0.127; CI - 0.198, - 0.056; P < 0.001). These changes were not significant for BMI-Z(score) (WMD: - 0.020; CI - 0.061, 0.021; P = 0.340). In dose-response meta-analysis, a non-linear association was reported between the duration of intervention and BMI (P-nonlinearity < 0.001) as well as BMI-Z(score) (P-nonlinearity = 0.023). In subgroup analysis, the more favorite results were observed for 5-10 years old, with combination of physical activity and diet as intervention materials. Conclusion In conclusion, the obesity prevention policies in short-term periods of less than 2 years, in rather early age of school with approaches of change in both of diet and physical activity, could be more effective in prevention of childhood obesity. Trial registration PROSPERO registration number: CRD42019138359