Childhood Obesity School Intervention: Study Results & Critique

Introduction: Childhood Obesity and School-Based Interventions

Since the early 1980s, childhood obesity has increased three-fold, and during the 2005–2006 school year an estimated 16% of American children were obese (reviewed by Gleason and Dodd, 2009). Childhood obesity and weight problems predispose children to physical and behavioral problems that can extend into their adult years (Centers for Disease Control and Prevention [CDC], 2010), and for this reason health researchers and educators are attempting to curb this epidemic.

K-12 schools provide between 35% and 47% of a child's daily nutritional requirements (reviewed by Gleason and Dodd, 2009), creating a meaningful opportunity to reduce the prevalence of childhood obesity in the United States.

Study Design and Methods

Towards this goal, a coalition of nutrition and educational researchers conducted a two-year pilot study to test the efficacy of a broad-based intervention strategy targeting obesity in 3,769 children attending grades 1–6 in a public school district in central Florida (Hollar et al., 2010). During this longitudinal, prospective cohort study, the intervention combined improvements in the quality of food available in schools—doubling the fiber content and reducing fat by 23%—along with nutritional and lifestyle education classes, increased opportunities for physical activity, and school-based wellness projects.

Of the five schools involved in the pilot study, one was chosen by the school district administrators to function as a control. The demographics of the intervention and control schools did not vary significantly, although there was a less than 20% difference in the number of Hispanic and White children.

Results and Interpretation

During the first year of the study, a 1.46 reduction in BMI (body mass index) was observed for children attending intervention schools, but this was not statistically significant because during the same period the control schoolchildren also lost weight (−0.95 BMI). BMI is a method used to assess whether a child or adult may be overweight or obese, using weight and height measurements (CDC, 2011). For example, the overweight range for a 9-year-old boy is a BMI score between 19.5 and 21.0, so a reduction of 1.46 would represent a 6.9% to 7.5% weight loss. During the second year of the study, children in the intervention schools experienced an average BMI reduction of 1.73, which was statistically significant in part because the control children lost less weight during this period (−0.47). Year to year, these results suggest that children enrolled in intervention schools would experience significant reductions in weight.

A related health measure used in this study was systolic and diastolic blood pressure (BP). Girls in the intervention program maintained lower systolic and diastolic BP during the summer months compared to controls, but the boys did not. This suggests that girls tended to maintain dietary habits adopted during the school year over the summer recess. BP measurements during the school year did not differ significantly from those of controls.

Another primary outcome measure was academic performance, as assessed by the FCAT (Florida Comprehensive Assessment Test). A number of studies have found an association between being overweight or obese and poorer K-12 academic performance (Roberts, Freed, and McCarthy, 2010), which may be related to the psychological problems that accompany this condition (Krukowski et al., 2009). Supporting this association, children attending intervention schools experienced a significant improvement in their math scores (p = 0.0005). Reading scores trended toward significance (p = 0.08).