Assessment Of Body Mass Index (BMI) Z-scores After One Year Of A School-based Health Intervention

Abstract

Approximately 17% of children in the United States, 2 to 19 years of age, are obese. Additionally, 41% of children, 6 to 17 years of age, in Philadelphia are obese or overweight. School-based interventions may positively influence body mass index (BMI) z-scores toward the age and sex-adjusted mean. PURPOSE: To assess change in BMI z-scores in elementary school students during the second year of a multi-year, ecological school-based health intervention, compared to students in control schools. METHODS: These data were collected from 317 students, enrolled in the fifth grade, of four intervention schools (n=202) and four control schools (n=115). The intervention included programs focused on improving nutritional intake and increasing physical activity, provided on a weekly basis. Height and body weight measurements were collected at the beginning and end of the school year. Body mass index z-scores were calculated using the World Health Organization calculations. RESULTS: BMI z-scores (± standard deviation) at baseline were 0.85±1.3 for intervention schools and 1.1±1.5 for control schools (p=0.12). Post-intervention (after one year) BMI z-scores were 0.83±1.3 for the intervention schools and 1.1±1.4 for the control schools (p=0.09). CONCLUSIONS: The intervention schools had a slight decline in their BMI z-scores, while the control schools had no change; however, there were no significant differences between the intervention and control schools. Although no significant changes were reported, there was a trend (p=0.09) for the intervention schools to decrease mean BMI z-scores. Assessment of BMI z-scores from additional years of this multi-year intervention may reveal more information about the change in BMI z-scores. Funding was provided by the Independence Blue Cross Foundation.