(Donnie Ray Jones/Flickr)
By Steve Schlozman, MD
Here are three recent headlines that got me thinking about kids and fat:
“Watching one hour of TV per day increases risk for obesity by 50%”
“Watching TV for Just an Hour a Day Can Make Children Obese”
“Study makes surprising link between TV time and childhood obesity”
Oversimplifications? Um, yes. Each of these headlines greatly simplifies (dare I say, incorrectly simplifies) a critical social and health issue. Personally, I don’t think TV is the sole evil culprit here. It’s far more complicated.
The medical community has long known that the amount of TV that a child watches correlates with obesity. We can even make some leaps from these data towards implicating causality. Unless your little ones happen to be doing aerobic exercises while they tune in to their cartoons, it’s easy to see how passive watching can equal active weight gain.
However, be wary of oversimplification and especially of the “one-size-fits-all” policy statements that these headlines often generate. The study authors here do, in fact, suggest further limiting TV exposure based on the existing American Academy of Pediatrics guidelines for young children as a means of controlling the rate of obesity in this country. (Currently, the AAP recommends limiting screen time to one to two hours or less for children over the age of 2, and discouraging screen time altogether for those who are younger.)
So, here’s the big question: Is the recommendation that TV time be further limited an entirely appropriate conclusion?
Beyond The Headlines
The answer, like many answers to social policy questions, is both yes and no.
What we know for certain is that we can’t really discern from the headlines what we ought to do, though there is ample reason to believe that most American rarely go beyond the headlines. Thus, we run the risk of jumping to more draconian conclusions than might be appropriate simply because we don’t have or take sufficient time to examine the flood of information.
How do we guard against this leap to oversimplification?
Here are a few key questions:
•Was there a large and diverse population studied?
There have been solid links between lower socioeconomic groups and some ethnic minorities and increased television time, as well as between lower socioeconomic groups and obesity.
The causes for both of these issues are of course multi-factorial. Fatty foods and higher calorie foods are cheaper. TV can function as a babysitter in households where parents are busy working and living paycheck to paycheck. However, the study in the headlines above, conducted by the Department of Education in conjunction with physicians at the University of Virginia, was indeed both large and diverse.
Over 12,000 children starting kindergarten were enrolled in the investigation, and a year later follow-up data was available for more than 10,000 of these children. These data included height and weight, as well as statistical analyses to account for differences in race, gender and socioeconomic effects. In other words, the numbers here are sufficiently large and diverse for us to feel comfortable drawing at least preliminary conclusions.
But beware, always beware, of flashy headlines. A Google search yielded all of the headlines above with equal weight, and yet one of the headlines clearly implicates causality. “Watching TV for just an hour a day can make a child obese.” (My italics.)
However, this study does not in any way suggest causality. There are a number of potentially unrelated factors that also happen everyday that might be associated with obesity, but not function as a cause of obesity. These could include behaviors like longer baths to cool down. We don’t know until we do the study whether longer baths would be associated with obesity. In other words, always be wary of blanket statements of causality with regard to the complexity of human behavior.
•What about the ample availability of screen-based material on demand? Perhaps the fact that children can often watch both what they want and when they want it affects their activity patterns in negative ways. We could ponder the fact that TV content, even for kids, has arguably (though not in all spheres) gotten better and of higher quality. There is even evidence that TV watching can improve behavior among kids, and this evidence also comes from the American Academy of Pediatrics. Does that mean we ought to make a policy statement advocating that TV should be less compelling?
Confessing My Bias
Things get even messier when we take the necessary step of examining our own personal biases. In my case, that examination includes a shameless confession regarding the ways my own penchants might complicate my interpretation of these data. Continue reading