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Monday, May 26, 2008

Do School-Based Obesity Interventions Work?

In light of the increasing number of overweight and obese kids, demand and focus on interventions aimed at school kids is increasing.

The questions, however, are:

1) is the school really the best place to intervene - or in other words, can the school compensate for poor environments in the home and the often poor parenting skills that may promote childhood obesity?

and perhaps more importantly,

2) do school-based invterventions actually work?

The latter issue was recently studied by Jonathan Kropski and colleagues from the Vanderbilt Centre for Evidence-Based Medicine, Nashville, Tennessee in a paper just out in OBESITY.

Kropski and colleagues performed a systematic review of all research published on this issue since 1990 and found only fourteen studies that were of sufficient quality to draw any conclusions. These included one nutrition-only progam, two physical activity promotion inverventions and eleven studies that combined both nutrition and activity interventions.

Based on the quality and results of these studies, only one study was designated as providing strong (grade 4 = randomzed controlled trial) evidence for the prevention of excessive weight gain in girls. Four weaker studies (observational data) provided some evidence of efficacy in boys and girls. The rest of the studies provided even weaker evidence for significantly improving measures of dietary intake, physical activity or both.

The bottom line is that from the current data, no conclusive evidence can be drawn regarding either the benefit or lack thereof for school-based intervention programs. There is certainly no evidence whatsoever that school-based interventions will indeed translate into less overweight or obesity in young adults.

Does this mean we sit back and give up? Certainly not - however, we must realise that pouring all our money into school programs as our primary approach to taming the obesity giant is based more on wishful thinking than on hard evidence.

The authors believe that despite the rather poor body of evidence, schools will play an important role in stemming current trends in overweight and obesity in children - but that is exactly it - for now this is nothing more than a "belief".

Clearly, we need more high-quality studies to determine whether or not investing in school programs is indeed cost-effective.

My guess is that without parents taking on an active role and policy makers doing all they can to reduce our current obesogenic environment, schools will have little say in the matter - but of course, I am happy to be proven wrong.

AMS
Edmonton, Alberta

3 comments:

Yoni Freedhoff said...

I'd love to see school based initiatives that taught kids about energy expenditure and calories and complemented themselves with posted calories in cafeterias.

Ideally nutrition and calories could be taught throughout the curriculum as the basis for things like reading comprehension, math problems etc.

Unfortunately most interventions involve physical fitness (which certainly won't do much in the way of calories burned) or through the reinforcement of non-evidence based, non-weight focused food guides like Canada's Food Guide and the American Food Pyramid.

Anonymous said...

Thanks Dr Sharma to bring this review to our attention.

We have to remember that school is only one amongst the different environments children ( from about age 5 ) evolve in.

Rather than asking if school-based interventions work, we need to ask what are the requirements for a school intervention to have some impact ?

As you asked: "can the school compensate for poor environments in the home and the often poor parenting skills that may promote childhood obesity ?"

Unfortunetely, for some children the school is the best thing that can happen to them. School B does not necessarely equal School A : the characteristics of a school, of its neiborhood is critical.
In some neighborhoods, a school intervention, defined in such a way that it meets the needs of the high-risk kids, could have an impact, but in another area with different characteristics there may be NO impact.

I agree with you that all the money should not be poured into school programs, but high-risk neighborhood with all thair problems should be a priority.

On the list of primary care: access to primary health care to me is critical.

Well in our dear province of Quebec there is a large number of children who do not have access to primary health care (except for early years vaccination): shortage of MD, nor enough nurses and a false perception that an annual check-up is irrelevant if you are not sick.

Another issue is an increase in psychological distress in the general population. Not only poor neighborhood. Well to do families too. Parental separation, one family parent, too busy parents are significant stress loads on the shoulder of children and of parents too. ....

So it is very clear as stated by Prof. James and Swinburn that mutilevel interventions are necessary. School based program for sure have a role however we need to define within waht framework it will have a significant impact.

Véronique A Pelletier MD, FRCP(C)
Staff Pediatrician
CHU Ste-Justine & U de Montréal

Anonymous said...

I agree with much of what you said, and while the body of literature may not be abundant in terms of evidence it is growing and shows support of the effectiveness of health promotion overall.

Health promotion and some prevention initiative outcomes are difficult to quantify but there is certainly evidence available that has shown positive results.

School-aged children and healthy weights (obesity prevention) is the focus in my current job and I am extremely passionate about it.

Yes, a portion of my job is wishful thinking in terms of results and obesity prevention, but the strongest guiding principle I have is beyond obesity prevention, that is, children's health in general.

We know that healthy kids learn better, behave better and are more apt to be active. Not rocket science. We also know that the nutrition and healthy living education they receive in the classroom is not always supported by the school environment. So perhaps, looking at school based healthy eating interventions is less about obesity and more about healthy outcomes in general. I'm hopeful that in time, the changes that are beginning to happen in the province will show some positive results in both health and the reduction of obesity in children.

The comprehensive school health approach considers the school, the home and the community in terms of children's health. I believe that each of these pieces play a critical role in prevention of obesity and positive health outcomes. No single piece will work alone. You are absolutely right about parent involvement, I'm still looking for the answer to the question "how can we get parents to buy in?"

I also think Dr. Paul Veugeler's work in the Annapolis Valley has certainly shown some very positive and optimistic outcomes! Let's hope we see similar results here in Alberta!

I'm sure you saw this article but wanted to pass it on anyway...

http://www.theglobeandmail.com/servlet/story/RTGAM.20080422.wlcafeteria22/BNStory/lifeFamily/home

http://www.temple.edu/newsroom/2007_2008/04/stories/pediatricstudy.htm

Did you get a chance to hear Mark Tremblay recently? He spoke a great deal about measurement inaccuracies in some studies and reports in terms of childhood obesity. How self-reporting and short study times may be skewing data policy is based on....more "food" for thought. His presentation is available:

http://www.centre4activeliving.ca/news/physical_activity_forum/2008childhood_obesity/edmonton.html