Healthier cafeteria choices, longer and more intense periods of physical activity and robust in-school education programs can lower rates of obesity and other risk factors for type 2 diabetes, according to a national study called HEALTHY.
"We found that innovative PE programs, healthier food choices in school lunches and snacks, and in-class lessons in healthy lifestyles can benefit those children most at-risk for developing type 2 diabetes and related conditions," says pediatrics professor Dr. Dan M. Cooper, UC Irvine’s principal investigator for HEALTHY.
"Because we worked with the existing school infrastructure, the lessons learned from this study can be readily applied throughout the nation."
UC Irvine was among eight academic medical centers nationwide participating in the three-year effort. Study findings were presented Sunday, June 27, at the American Diabetes Association’s 70th Scientific Sessions event in Orlando, Fla., and appear in The New England Journal of Medicine.
Because type 2 diabetes disproportionately affects minorities and low-income people, the study was conducted in U.S. schools with high enrollments of minority children — 54 percent Latino and 18 percent African American, on average — and kids from low-income families. Researchs from UC Irvine's School of Medicine partnered with middle schools in the Long Beach Unified School District: Bancroft, DeMille, Hoover, Hughes, Marshall and Stephens.
Nationwide, 4,603 students in 42 middle schools were tracked from the beginning of sixth grade through the completion of eighth grade. Half the schools were randomly chosen to implement the study’s “intervention” program of longer gym classes, more nutritious food choices, classroom education units and other schoolwide activities encouraging healthy behaviors.
The “comparison” schools got no specific intervention but did receive discretionary funds for food options and physical activities of their own choosing. Parents at all UC Irvine-participant schools were given written feedback on student health screenings and notified if their children were found to be at high risk for diabetes.
At the beginning of the study, many sixth-graders at both intervention and comparison schools were considered in jeopardy. Nearly half were overweight or obese, 16 percent had elevated fasting blood glucose levels, and nearly 7 percent had elevated fasting insulin levels — all risk factors for developing type 2 diabetes.
At the end of the study, researchers found that the then-eighth-grade students in intervention schools who had been overweight or obese in sixth grade had a 21 percent lower rate of obesity than their counterparts in comparison schools. Students at intervention schools also had lower average levels of fasting insulin and smaller average waist circumferences.
Surprisingly, the number of overweight and obese students declined in both intervention and comparison schools. Additionally, the study groups did not differ in mean glucose levels or the percentage of students with elevated fasting glucose in the overweight category.
"We do not completely understand why there were improvements in both the intervention and comparison schools," Cooper says. "We do know, however, that in our schools here in Long Beach, many of the innovative approaches to PE and school food choices that we started in the intervention schools found their way to the comparison schools as well. The teachers and staff in the school system are very concerned about the problem of obesity and are always looking for ways to improve the health of children."
Over the course of the study, intervention schools provided students with low-fat, high-fiber foods and more fruits and vegetables, with an emphasis on water, low-fat milk and drinks with no added sugar. These students also had longer, more intense periods of physical activity — defined as achieving a heart rate of at least 140 beats per minute, with a target of 150 minutes or more of such activity every 10 days. And they were involved in highly interactive, small-group classroom activities and awareness campaigns promoting long-term healthy behaviors.
Other research centers participating in the study were: Baylor College of Medicine in Houston; George Washington University in Washington, D.C.; Oregon Health & Science University in Portland; Temple University in Philadelphia; University of North Carolina at Chapel Hill; University of Pittsburgh Medical Center; and University of Texas Health Science Center at San Antonio. The National Institute of Diabetes and Digestive & Kidney Diseases, a branch of the National Institutes of Health, and the American Diabetes Association funded the study.
— Tom Vasich, University Communications