A recent study by the National Institutes of Health on whether school health programs affect obesity and diabetes rates came up with some surprising results. While programs promoting a healthy diet and exercise had a positive influence on weight and insulin levels, researchers happily found that for reasons unknown, obesity rates among the students declined across the board - school programs or not.

The report, "A School-Based Intervention for Diabetes Risk Reduction," found that kids who participated in a program did achieve some positive results, including a decrease in the number who started out obese and a reduction in insulin levels, which the study authors said "may reduce the risk of childhood-onset type 2 diabetes." Overall, however, there was not a significant difference in overweight and obesity rates between the kids who participated in the program (the program group) and those who did not (the control group).

The lack of difference in weight loss rates between the control and program groups is where researchers found the study's twist. The control group that didn't participate in the program also had a drop in overweight and obesity rates right along with the program group.

A body mass index or BMI of 30 or greater for adults is considered obese and a BMI of 25 or greater but less than 30 is overweight. For children and teens, these definitions are based on a comparison to other students in the control and program groups. So the number of obese students (with a BMI in the 95th percentile or higher) in the control group declined by 3.8 percent, while the number in the intervention group dropped by 5.5 percent.

When the study began, in spring 2006, 30 percent of students in both the program group and the control group were obese. At the end of the study, 24.6 percent of the program group and 26.6 percent of the control group were obese. When looking at overweight and obese kids (with a BMI in the 85th percentile or higher), the percentage dropped from 50 to 45 percent over the course of the study for both groups.

The findings were reported in the New England Journal of Medicine in late June.

The study's authors saw the findings as good, if not entirely clear, news. "That's the perplexing but happy part of this," the study's chairman, Dr. Gary D. Foster told the New York Times. "Something is going on in the environment that is leading kids to become less overweight or obese. We need to find out what it is and do more of it."

With childhood obesity at all time high - 16 percent of kids 6-19 are overweight and 19 percent are obese according to the Center for Disease Control - the study's findings shed some needed positive light on a serious national issue that doesn't stop once kids become adults. Obese children often become obese adults, says the CDC, with a higher risk of health problems.

Adult obesity is one of the twenty key health measures identified for State of the USA by the Institute of Medicine.

Study Methodology

The study included 4,603 sixth-graders, with a larger proportion of Black and Hispanic students (groups more at risk for diabetes). At the start of 6th grade, in fall 2006, each student's body mass index, waist circumference and fasting glucose and insulin levels were tested. The tests were repeated at the end of their 8th grade year in the spring of 2009.

(New England Journal of Medicine (PDF), New York Times, Center for Disease Control)