Effect of interventions on the body mass index of school-age students

OBJECTIVE: To evaluate the effect of intervention programs using nutritional education, physical activity or both on the reduction of body mass index in school-age students. METHODS: The systematic review with meta-analysis included randomized controlled studies available from the following electronic databases for the years 1998 to 2010: PubMed, Lilacs, Embase, Scopus, Web of Science and Cochrane Library. The descriptors were: randomized controlled trial, overweight, obesity, body mass index, child, adolescent, physical activity, nutrition education and Schools. A weighted average was based on the standardized means difference and used a 95% confidence interval. The inconsistency test was utilized to evaluate the heterogeneity of studies. RESULTS: Initially, 995 studies were identified, of which 23 were included, and 3 meta-analyses were performed. Isolated physical activity interventions did not present a significant reduction in BMI, with a standardized mean difference of -0.02 (95% CI: -0.08; 0.04). A similar result (n=3,524) was observed in the isolated interventions of nutritional education, with a standardized mean difference of -0.03 (95% CI: -0.10; 0.04). When the interventions with physical activity and nutritional education were combined, the result of the meta-analysis (n=9,997) presented a statistically significant effect in the reduction of body mass index in school-age students, with a standardized mean difference: -0.37 (95% CI: -0.63; -0.12). CONCLUSIONS: The interventions that combined physical activity and nutritional education had more positive effects in the reduction of body mass index among school-age students than when they were applied individually.