Results of a Systematic Review of Reviews: What do we know about the effectiveness of policy and environmental approaches to address obesity in the school environment?

Background: As one component of the Centers for Disease Control and Prevention (CDC) funded Community Transformation Grants, CDC is conducting a series of reviews summarizing findings from published systematic reviews and meta-analyses. This review examines three categories of interventions in school settings: active living, healthy eating, and healthy and safe physical environments. Methods: To be included in this review, papers were published between 01/2000-07/2011, and presented results from a narrative review, systematic review, or meta-analysis. Eleven databases were searched. We examined data by the type of and how much evidence was available for each intervention category. Results: We included 120 papers based on abstract review; and 42 of these met our inclusion criteria and were fully assessed. We found the most evidence for successful intervention outcomes for interventions based on 1) improving school food and drink offerings that align with Institute of Medicine standards and 2) increasing student's time spent in moderate-to-vigorous physical activity during physical education class. Evidence from systematic reviews is lacking for strategies regarding increased adoption of approaches to enhance walking, bicycling, and active transportation to and from school; farm-to-school strategies; and joint-use agreements. Conclusions: While there is some evidence for interventions that support a healthier school environment, the evidence-base is limited for several strategies currently being implemented by school districts around the US. Research and evaluation should focus on environmental strategies currently not supported by the evidence-base, and efforts should be made to use common measures and larger, more diverse samples to fill the evidence gaps.