Background: With the aim of contributing to he Healthy Goal 2010 of reducing significantly the prevalence of childhood obesity 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 (1st to 7th 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 <0.001 versus p =0.0034 in girls), while in controls, BMI Z scores increased. Obesity prevalence declined significantly in experimental schools; from 17 to 12.3% and from 14.1 to 10.3% in boys and girls respectively, while in the control group, it remained unchanged. Also, triceps skinfold in girls from Casablanca increased significantly less than that of control girls.
Conclusion: This intervention proved that it is possible to reduce significantly the prevalence of obesity in Chilean schoolchildren attending public elementary schools.