Healthier cafeteria choices, longer and more intense periods of physical activity and a robust in-school education program can lower the risk of obesity and other risk factors for acquiring type 2 diabetes, according to a new study called HEALTHY. The findings are published online in the New England Journal of Medicine.
Oregon Health & Science University is one of eight academic medical centers nationwide chosen to participate in the study funded by the National Institute of Diabetes and Digestive and Kidney Diseases, a branch of the National Institutes of Health, and the American Diabetes Association.
Because type 2 diabetes disproportionately affects minorities and low-income people, the study was conducted in schools with a high enrollment of minority children, 54 percent Hispanic and 18 percent Black, and youth from low-income families.
“This is the first-ever study to show you can reduce obesity and risks for type 2 diabetes in kids and do it in schools with at-risk, high ethnic-minority populations,” said Linn Goldberg, M.D., the HEALTHY principal investigator at OHSU, and professor and head of the Division of Health Promotion and Sports Medicine in the OHSU School of Medicine. “This study emphasizes the fact that schools can have a tremendous positive impact on a child’s health.”
The study tracked 4,603 students in 42 middle schools nationwide from the beginning of sixth through the completion of eighth grade. Half the schools were randomly assigned to receive an “intervention” comprising healthier food choices, longer gym classes, classroom behavioral education and other schoolwide activities that encourage healthy behaviors.
The “comparison” schools received no specific intervention, but did receive funds to use at their discretion. Comparison schools continued to provide food choices and physical education activities based on their own choice. All parents received written feedback about student health screening results with notification from an OHSU endocrinologist and referral to a physician if student results were high risk.
At the beginning of the study, many sixth-grade students at both the intervention and comparison schools were at high risk for diabetes. 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, the researchers found the now eighth-grade students in intervention schools who were overweight or obese in the sixth grade had 21 percent lower odds of being obese compared with students in comparison schools. Students at intervention schools also had lower average levels of fasting insulin and smaller waist circumference.
Surprisingly, the researchers also found that the number of overweight and obese students had declined in both the intervention and the comparison schools. And, the study groups did not differ in mean glucose levels or the percentage of students with elevated fasting glucose in the overweight category.
“Although more research is needed to better understand why all schools showed improvement, possible explanations were that comparison schools’ parents received information about their child’s risk and may have made healthy changes, and comparison schools volunteering to be in the study did so out of concern for the health of their student body, and thus may have made subsequent changes in the school environment,” explained Goldberg.
Over the course of the three-year 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. Intervention school students also participated in longer, more intense periods of physical activity, defined as achieving a heart rate of at least 130 beats per minute with a target of 150 minutes or more of such activity per 10 days. And, they were involved in classroom activities that were highly interactive in small learning groups, along with awareness campaigns that promoted long-term healthy behaviors.
Oregon schools participating in the study include: French Prairie Middle School, Woodburn; Parrish Middle School, Salem; Reynolds Middle School, Fairview; Waldo Middle School, Salem; H.B. Lee Middle School, Portland; and Wy'east Middle School, Hood River.
Other research centers participating in the study include: Baylor College of Medicine, Houston, Texas; University of California at Irvine; University of North Carolina at Chapel Hill; Temple University, Philadelphia, Pennsylvania; University of Pittsburgh Medical Center; University of Texas Health Science Center at San Antonio; and George Washington University, Washington, D.C.
About 24 million people in the United States have diabetes. It is the main cause of kidney failure, limb amputations, and new onset blindness in adults and a major cause of heart disease and stroke. The longer a person has diabetes, the greater the chances of developing serious damage to the eyes, nerves, heart, kidneys, and blood vessels. Type 2 diabetes, which accounts for up to 95 percent of all diabetes cases, becomes more common with increasing age. It is strongly associated with obesity, inactivity, family history of diabetes, history of gestational diabetes, impaired glucose metabolism, and racial or ethnic background. The prevalence of diagnosed diabetes has more than doubled in the last 30 years, due in large part to the upsurge in obesity. For more information about diabetes, visit http://diabetes.niddk.nih.gov/index.htm.
About Oregon Health & Science University
Oregon Health & Science University is the state's only health and research university and Oregon's only academic health center. OHSU is Portland's largest employer and the fourth largest in Oregon (excluding government). OHSU's size contributes to its ability to provide many services and community support activities not found anywhere else in the state. It serves patients from every corner of the state, and is a conduit for learning for more than 3,400 students and trainees. OHSU is the source of more than 200 community outreach programs that bring health and education services to every county in the state.
About the NIDDK
NIDDK, part of the NIH, conducts and supports basic and clinical research and research training on some of the most common, severe and disabling conditions affecting Americans. The Institute's research interests include diabetes and other endocrine and metabolic diseases; digestive diseases, nutrition, and obesity; and kidney, urologic and hematologic diseases. For more information, visit www.niddk.nih.gov.