Effectiveness of a dietary and physical activity intervention to prevent obesity in school age children

Background: With the aim of contributing to be Healthy Goal 2010 of reducing significantly the prevalence of childhood obestiy, we developed and implemented during 2003 and 2004, a school-based obesity prevention intervention which included nutrition education and the promotion of physical activity. Aim: To report the results of the intervention. Material and methods: The sample included 1760 children (1(st) to 7(th) grade) from 3 elementary public schools in Casablanca (experimental group) and 671 from a similar school located in Quillota, a neighboring city (control). Primary outcomes were body mass index (BMI) Z score, the mile and shuttle-run tests and obesity prevalence. We also compared changes in waist circumference and triceps skinfold between both groups. Effectiveness of the intervention was assessed by analyzing separately the group *age* time interaction for the first 3 outcomes (follow-up-baseline), using a mixed model of covariance and by comparing variations in obesity prevalence between both groups. Results: There was a significant decline in BMI Z scores in experimental schools for both genders, but greater in boys (p