Effect of an Environmental School-Based Obesity Prevention Program on Changes in Body Fat and Body Weight: A Randomized Trial.
Author Interview: Donald A. Williamson, Ph.D.
Pennington Biomedical Research Center
What are the main findings of the study?
A school-based obesity prevention program that modified the school environment to promote healthy eating, increased physical activity, and decreased sedentary behavior was effective for reducing body fat in boys and attenuating body fat gain in girls. Students in grades 4 to 6 at the beginning of the three year study participated in the cluster randomized controlled trial. Students were all from rural communities of Louisiana, USA.
Were any of the findings unexpected?
A secondary prevention approach that used classroom instruction and an internet-based program was combined with the environmental program and its effects were contrasted with a control group and the environmental program alone. We found that this secondary prevention program did not enhance the obesity prevention effects of the environmental program. This finding was unexpected.
What should clinicians and patients take away from this study?
The study found that the environmental program had modest effects on body fat in boys and girls from rural communities. Most participants were African-American and poor. This finding is important for several reasons. The environmental program is relatively inexpensive, especially in comparison to clinical treatment and more intensive programs such as the secondary prevention program that was tested in the study. The environmental program had broad effects on changes in body fat, nutrition, physical activity, and sedentary behavior. These effects were observed in an underserved population, mostly poor rural children, and it was effective for a range of children including obese and non-obese, boys and girls, and white and African-American children. The breadth of the effects should be understood within the context of relatively small effects on adiposity and health behaviors of the entire study cohort. These small population effects should be regarded as one tool in the fight against childhood obesity, but should not be viewed as a replacement for clinical treatment of children who are already significantly overweight.
What recommendations do you have for future research as a result of your study?
The potential costs and health consequences of the childhood obesity epidemic have been well documented. Thus, finding a solution to this problem is vital to the health of modern societies. The findings of this study, in combination with the findings from other relatively long-term school-based obesity prevention studies, suggest that school-based obesity prevention can be effective if the intervention is implemented over a period lasting several academic years.
The results, however, must be anticipated with realistic expectations: the effects on adiposity and health behaviors will be modest and will be insufficient to manage the health risks associated with overweight and obese status that is already present. This observation suggests that a comprehensive solution to the childhood obesity epidemic should be multi-tiered, offering primary prevention as a first-line defense and clinical treatment or secondary prevention as an option for children who are already overweight or obese. Future research should test the efficacy of such multi-tiered approaches to find the most effective and least costly solution to the childhood obesity epidemic.
Citation and Abstract:
Effect of an Environmental School-Based Obesity Prevention Program on Changes in Body Fat and Body Weight: A Randomized Trial.
Williamson DA, Champagne CM, Harsha DW, Han H, Martin CK, Newton Jr RL,
Sothern MS, Stewart TM, Webber LS, Ryan DH.
1] Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA [2] Department of Psychology, Louisiana State University, Baton Rouge, Louisiana, USA.Obesity (Silver Spring). 2012 Mar 8. doi: 10.1038/oby.2012.60. [Epub ahead of print]
Abstract
This study tested the efficacy of two school-based programs for prevention of body weight/fat gain in comparison to a control group, in all participants and in overweight children.
The Louisiana (LA) Health study utilized a longitudinal, cluster randomized three-arm controlled design, with 28 months of follow-up. Children (N = 2,060; mean age = 10.5 years, SD = 1.2) from rural communities in grades 4-6 participated in the study. Seventeen school clusters (mean = 123 children/cluster) were randomly assigned to one of three prevention arms: (i) primary prevention (PP), an environmental modification (EM) program, (ii) primary + secondary prevention (PP+SP), the environmental program with an added classroom and internet education component, or (iii) control (C).
Primary outcomes were changes in percent body fat and BMI z scores. Secondary outcomes were changes in behaviors related to energy balance. Comparisons of PP, PP+SP, and C on changes in body fat and BMI z scores found no differences. PP and PP+SP study arms were combined to create an EM arm. Relative to C, EM decreased body fat for boys (-1.7 ± 0.38% vs. -0.14 ± 0.69%) and attenuated fat gain for girls (2.9 ± 0.22% vs. 3.93 ± 0.37%), but standardized effect sizes were relatively small (<0.30).
In conclusion, this school-based EM programs had modest beneficial effects on changes in percent body fat. Addition of a classroom/internet program to the environmental program did not enhance weight/fat gain prevention, but did impact physical activity and social support in overweight children.