[Randomized controlled school based interventions to prevent childhood obesity: systematic review from 2006 to 2009].

The prevalence of overweight and obesity in children has increased to epidemic levels. Several authors have suggested that school is the best place for effective prevention programs. The purpose of this systematic review was to assess the evidence of randomized controlled trials concerning long-term (equal to or more than 9 months) observations at schools and published in the database of MEDLINE/Pubmed from January 1st of 2006 to February 28 of 2009. Ten studies were analyzed. Overall, regarding the design, the intervention components, target population age, intervention periods, educational techniques, cultural characteristics of the population, and outcome measures were heterogeneous. The results were modest. The outcomes showed a positive impact on lifestyle as intakes of fruits and vegetables increased, consumption of sugar-sweetened carbonated beverages decreased, and sedentary behaviors and adiposity were reduced. Generally, there were no significant reductions for BMI. These results warrant more strategies to achieve parental involvement, reduction of dropouts, and additional studies assessing different educational systems and cultural environments, including those in Latin America. Longer follow-up periods are also required.