School-based Intervention Lowers Obesity Rate in Children at Risk for Diabetes

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Researchers recently announced results from the HEALTHY clinical trial, led by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The 3-year study, conducted in middle schools with a high enrollment of minority youth from low-income families, found that a school-based intervention could lower the obesity rate in students at highest risk for type 2 diabetes—those who started out overweight or obese in sixth grade. However, schools that implemented the intervention did not differ from comparison schools in the study’s primary outcome—the prevalence of overweight and obesity combined.

Type 2 diabetes is an emerging health problem in youth, particularly minority youth, being driven by the obesity epidemic. The HEALTHY study’s results were published in the July 29, 2010, issue of The New England Journal of Medicine.

The intervention included changes in school food services; longer, more intense periods of physical education; and classroom activities to promote behavior change. Conducted from the beginning of the sixth grade to the end of the eighth, the study involved 4,600 students attending 42 middle schools in seven areas of the United States. Half of the schools implemented the program, and the other half served as comparison schools.

When students were first evaluated in sixth grade, about half were overweight or obese. Many had other risk factors for type 2 diabetes, such as a first-degree relative with diabetes, large waist size, and elevated blood glucose and insulin levels. By the end of the study, the number of overweight and obese students had declined by 4 percent in both comparison and program schools. One possible explanation for this result is that comparison schools may have independently implemented healthful changes to the school environment because of increased awareness about the problem of childhood obesity fostered by the study.

Program schools outperformed comparison schools in several areas. Among children in the study who started out overweight or obese in the sixth grade, children in program schools had 21 percent lower odds of being obese at the end of the study than similar students in comparison schools, a statistically significant difference. The percentage of children with waist size above the 90th percentile was lower in program schools than in comparison schools. Insulin levels were also lower in program schools. High insulin levels or a large waist increase the risk of developing type 2 diabetes, independent of body weight. High insulin levels reflect insulin resistance, the first step on the path to type 2 diabetes.

“The study shows that a school-based program can help lower obesity and certain risk factors for type 2 diabetes in youth at high risk for the disease,” said Griffin P. Rodgers, M.D., M.A.C.P., director of the NIDDK.

Visit the HEALTHY study’s website, www.healthystudy.org, and www2.niddk.nih.gov/Research/ClinicalResearch/HEALTHY/QandA for additional information about the study.