Only it's not called clumsiness, it's called, "developmental coordination disorder" (DCD) and it reportedly is found in 5-6% of school aged children and according to the authors of a study published this week in the Canadian Medical Association Journal, kids with DCD are at higher risk of overweight and obesity.
The study looked at 2083 children of whom 111 were deemed to suffer from DCD (excluding kids who had physical or mental illnesses).
At baseline the Grade 4 DCD kids were already behind the eight ball having 15% higher mean BMIs and 13% higher waist circumferences than their coordinated peers - a trend that grew through Grade 6.
While this study certainly does seem to draw a strong correlation between clumsiness and obesity these findings can't even remotely be construed as meaning DCD kids' lack of exercise is the cause of the increase in risk - especially given the authors didn't measure how much any of the kids were exercising. Of course that didn't stop the authors from making that stretch in their abstract's introductory statement,
"Children with developmental coordination disorder have been found to be less likely to participate in physical activities and therefore may be at increased risk of overweight and obesity."A statement which when considering the study is meant to determine whether or not DCD is associated with increased obesity risk certainly lends literary (not evidentiary) credence to the notion it's due to these kids' decreased activity levels.
So what else might be going on with here? Off the top of my head here are 3 other potential clumsy weight related confounders:
1. Perhaps the DCD kids drown their uncoordinated sorrows in a few extra Big Gulps every week. While that may seem trite, if the theory is that these kids aren't playing organized or even playground sports certainly it's plausible that they might eat more during their extra free time and may as well be more likely to be comforting themselves with food.
2. Perhaps the DCD kids are kids who come from less nurturing or less privileged homes where their parents may not have had the time, inclination or funds to support things like dance lessons, soccer camps or simple let play together time leading to lesser motor developments. In turn those same homes may well have different dietary and social environments that could account for the differences found herein.
3. Perhaps as my friend and colleague Arya Sharma suggested in his blog yesterday, it's the overweight and obesity that causes DCD rather than the other way around.
And I'd argue that one of those options is far more likely to be causal than a lack of exercise as frankly the amount of exercise that would need to be accrued by age 10 to account for such a significant difference in body weight would be truly phenomenal especially given the fact that other studies have found that even a ten fold difference in childhood exercise didn't impact on body weight.
Ultimately this is an interesting study with interesting results, I just wish it wasn't painted with the all too common exercise is the cure-all and cause-all for childhood obesity brush as I think it's much more likely that obesity leads to clumsiness rather than the other way around and likelier still that there's something else in the mix that's not being accounted for here.
Hopefully the next round of studies on these kids will either help elucidate a more plausible mechanism for the association or prove me dead wrong in that indeed it's all about exercise - either way, I'll be sure to blog about it.
Cairney, J., Hay, J., Veldhuizen, S., Missiuna, C., Mahlberg, N., & Faught, B. (2010). Trajectories of relative weight and waist circumference among children with and without developmental coordination disorder Canadian Medical Association Journal DOI: 10.1503/cmaj.091454
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I have a local pediatric orthopedic MD who sends me overweight kids with plenty of physical developmental problems. This study is just the beginning of a cascade of children becoming clinical customers due to obesity.
ReplyDeleteI have a child with DCD. He's NOT clumsy, but rather has such difficulty with developing motor skills that even his speech and writing were greatly delayed and required intervention/therapy. He's thin, but I can see how this disorder puts one at risk of becoming overweight: coordination and active play is difficult, so it's easier not to bother. Add in teasing for looking awkward, not being able to easily participate in our sports-centred youth culture, and general feelings of anxiety and inadequacy, you end up with a kid who probably grossly under-moves and may emotionally medicate with food.
ReplyDeleteI get your point, but my thin kid has the advantage of an RD mother, and parents who can afford not only various extra-curriculars, but all the private therapy he needs to bring his physical development up to age-appropriate standards. He was physically delayed from the beginning -- learning to sit, crawl, walk, run, climb, etc later than his peers. How can that NOT add up over a child's life and be "phenomenal"?
It seems to me you are blaming DCD on environment (obesity, less privileged homes). Would you care to elaborate on confounders #2 & 3? It's not something that just appears at age 9 because a kid is fat and can't keep up with his friends.
Anonymous,
ReplyDeleteRegarding point number two, clearly your home is not anything like what I've postulated and certainly were all the DCD kids' homes in this study like yours, my point would be moot.
My point though was that the authors of this study didn't look into any variables that might impact on a child's diagnosis of DCD and consequently makes the inferred correlation of DCD leads to obesity due to the causal impact of a lack of exercise difficult to swallow.
While certainly your experience with your own child is important, from a scientific perspective it is important to ensure that we're talking about apples and apples and while your kid may be an apple, others may be oranges and this study does virtually nothing to ensure fair comparisons are being made.
"Leads to obesity" may be too strong a statement at this time in the research, however, my point is that it's not just a lack of exercise, but a child's lifetime of potential less movement. It's not a superficial issue of being clumsy and so preferring to watch TV. While disparaging the study, you were glib about what DCD actually is and how it affects children.
ReplyDeleteI wasn't glib in the slightest.
ReplyDeleteThis study did not in fact have the children meet DCD criteria and they were diagnosed by research assistants and the only criteria they needed to meet was that they demonstrated difficulties with coordination. The other 3 criteria were ignored and hence my query as to other potential causes of "DCD" in the cohort.