School-Based Program Fell Short of Weight-Loss Goals

ORLANDO — A school-based program designed to increase activity and improve nutrition failed to meet its primary goal—decreasing the combined prevalence of overweight and obesity in middle schoolers—but it did improve other measures of obesity, such as body mass index and waist circumference.

The findings show that schools can positively impact several important risk factors for diabetes. Providing healthier meal and snack options, stepping up physical education classes, and creating a culture where healthy behaviors are encouraged all foster the growth of healthier children, Dr. Gary Foster said at a press briefing during the meeting. The results were simultaneously published online (N. Engl. J. Med. 2010 June 27[doi: 10.1056/NEJMoa1001933])

The finding that both intervention and control schools equally decreased their prevalence of overweight and obesity is actually a very positive one, said Dr. Foster, lead study author and an endocrinologist at Temple University, Philadelphia.

“This signals that there is potentially very good news, that the rate of obesity in middle schoolers appears to be declining,” probably because of secular trends, he said in an interview.

The 3-year HEALTHY study looked at promoting behavioral changes in 42 middle schools that had a high proportion of obese children. In each school, at least half of the students were overweight or obese when they entered the 6th grade in 2006.

The program was implemented at 21 schools; the other 21 schools had the same baseline and follow-up health sampling and recruitment and retention strategies, but no other program interventions. At baseline, all the 6th graders in each school underwent measurements of weight, height, waist circumference, blood pressure, glucose level, and insulin level. These measurements were repeated at the end of the study, when they were about to graduate from 8th grade.

At baseline, parents of all of the children received a letter about their child's health status, including notification of abnormal weight or blood tests. They also received health information and encouragement to follow up with their child's pediatrician.

The intervention consisted of:

▸ A nutritional component that targeted the quantity and quality of foods in the set and à la carte lunch menus, snack machines, snack bars, school stores, and classroom celebrations, focusing of more fruits, vegetables, whole grains, low-fat milk, and water;

▸ An activity component, increasing the amount of time in moderate to vigorous physical education classes;

▸ A behavioral component, targeting self-awareness, self-monitoring, goal setting, and behavioral change.

The schools received financial incentives for participation, including grant money and money to purchase new physical education equipment. Teachers received hourly compensation for the training they received. Students also received monetary incentives for enrolling in the program and staying in until completion.

At the study's end, both schools experienced a significant 4% reduction in the prevalence of overweight and obesity among students. However, Dr. Foster said, schools in the intervention arm did achieve some improvements in secondary end points, compared with control schools.

Intervention schools saw a greater (but nonsignificant) decline in the percentage of students with a BMI at or above the 95th percentile, compared with the control schools (−5.5% vs. −3.8%). Intervention schools also had fewer students with a waist circumference at or above the 90th percentile than control schools at the end of the study (21% vs. 23%). Among the subgroup of children who were overweight or obese at the beginning of the study, the 3-year difference in waist circumference was significant between the intervention and control schools (−17% vs. −13%). Students at the intervention schools who were overweight or obese in 6th grade were also 21% less likely than those in control schools to still be overweight in 8th grade—a significant difference. Also among that group, there was a nonsignificant trend toward a greater reduction in BMI z-scores for children in the intervention group.

The secondary end point of improved waist circumference could be a very important finding, Dr. Philip Zeitler said during the discussion. Insulin resistance rises with the onset of puberty in all children; thus, puberty is a time when children who are overweight or obese face a very sharp increase in their chance of developing type 2 diabetes. An intervention that decreases waist circumference could be just enough to get children through this natural “danger period” into a more mature growth phase, when the risk will naturally decrease, said Dr. Zeitler, a pediatric endocrinologist at the University of Colorado, Denver.