In an early release from the New England Journal of Medicine, researchers documented the effects of a 3 year, 21 school, 4,600 student, multi-pronged, intervention that spanned Grades 6 through 8 covering nutrition, physical activity, behavioural knowledge, communications and social marketing on the children's body mass indices, waist circumferences, fasting glucoses and fasting insulins.
The nutritional component targeted quantity, quality and energy of foods. The physical activity component was meant to increase baseline physical activity and to teach the energy components therein. The behavioural component targeted goal setting and self monitoring while the communication and social marketing component integrated it all.
Results wise - they were a bit odd but truly heartening nonetheless.
First the odd. Apparently not only did the 21 intervention schools demonstrate a reduction in the prevalence of overweight and obesity over the study's time span strangely so too did the controls.
Next the hopeful. There was a very nearly significant reduction in obesity in the intervention schools with kids there being 19% less likely to be obese at the end of the study than the beginning (p=0.05). There was also a statistically significant decrease in the percentage of intervention kids who ended up in the >90th percentile for BMI and waist circumference though the differences were relatively small. Interestingly, the intervention seemed to have a more dramatic impact on those who were overweight or obese to begin with at the study's start.
Now the important. While sugar wise there were no differences in fasting glucose between control and intervention schools, by Grade 8, the intervention schools' kids had better fasting insulins which if sustained, might in fact decrease their likelihoods of developing type 2 diabetes down the road.
But the most heartening piece has to be the fact that although the differences themselves were small, the study did indeed demonstrate that a multi-dimensional intervention grounded in energy balance, with explicit, appropriate and careful teaching about calories in and out, over just a 3 year period, in just a single venue, can in fact impact on the severity of obesity, its progression and its potential co-morbidities.
To me what this study really demonstrates is that in the race to build a levee for the flood waters of childhood obesity, while it may be of some benefit to target older kids in schools, ultimately to have a real impact we'll need to help affect a more dramatic environmental overhaul as has been done with the Epode study in France, yet here we have an example of an effective school based sandbag to help tame the flood.
But don't get too excited yet for as Yale's Dr. David Katz has mentioned, "To contain a flood no single sandbag will do" and while schools certainly are an important sandbag they need to be complemented multi-sectorially with interventions being initiated at much younger ages across entire communities and run indefinitely.
The part that had me almost jumping for joy? The fact that there are folks out there who have successfully and explicitly taught the unfortunately and strangely taboo subject of caloric balance to children - a subject ignored by the vast majority of weight-related public health interventions despite the fact that understanding caloric balance is undoubtedly the single most important cornerstone to navigating our modern obesogenic environment.
[For those interested the intervention materials themselves are extensive and are available online at the Healthy Study website.]
The Healthy Study Group (2010). A School-Based Intervention for Diabetes Risk Reduction New England Journal of Medicine DOI: 10.1056/NEJMoa1001933