Clumsy Kids More Prone to Obesity?Tuesday, June 29, 2010
Yesterday, I blogged about the finding that increased body fat appears to precede lower activity levels and not the other way round (which is probably why attempts to increase physical activity in kids has so far not done much in terms of obesity prevention).
Almost on cue, the latest issue of the Canadian Medical Association Journal (CMAJ) publishes a study by McMaster University’s John Cairney and colleagues, suggesting that kids with developmental coordination problem (perhaps unfairly described as “clumsiness”) may be particularly prone to weight gain.
The study builds on previous reports that kids with developmental coordination disorder were found to be less likely to participate in physical activities.
The researchers studied 2278 (95.8%) of 2378 fourth grade kids (ages 9 to 10) from 75 schools in southwestern Ontario, Canada. Children were followed up over two years, from the spring of 2005 to the spring of 2007.
Not only did the 111 children (46 boys and 65 girls) who had possible developmental coordination disorder have a higher mean BMI and waist circumference at baseline than the other kids, but these differences persisted or increased slightly over time.
In fact, kids with with possible developmental coordination disorder were four times more likely to become obese over the course of the study.
While this study is of course strongly suggestive of less physical activity being a risk factor for childhood obesity, it should be noted that the researchers did not directly measure activity levels. There was also no report of their energy intake or their mental health status (e.g. cognitive ability, depression, attention deficit disorder, etc.), which may significantly affect ingestive behaviours.
There was also no mention of low birth weight, which may be associated both with developmental coordination disorder and excess post-partum weight gain.
Finally, as the authors themselves are careful to note, obese kids have been noted to be less coordinated – so again, it is not clear if the sequence here is “clumsiness -> inactivity -> obesity” or “obesity -> inactivity -> clumsiness” or even “obesity -> clumsiness -> inactivity”.
As always, solving ‘chicken or egg’ questions from cross-sectional or even longitudinal data remains challenging. This is exactly why we need more intervention studies.