The evils of too much screen time have been discussed before on this blog, ranging from the
They are about to be discussed again.
This time, however, we will talk about the evils of having a screen in your child's bedroom, particularly a television screen, even if that television screen is turned off.
The American Academy of Pediatrics Committee on Public Education has already recommended television-free bedrooms for children.
In a study published this month in JAMA Pediatrics, researchers found that having a television in a child's bedroom is associated with weight gain, and that association persists regardless of how much TV the child actually watches.
Using data drawn from the Dartmouth Media Study, lead author Diane Gilbert-Diamond, ScD, and colleagues followed a group of over 6,500 children that was representative of the national population in terms of their race, weight, household income, and parents' education level. The children were on average 12 years old at the start of the study, when they and their parents were interviewed via telephone about Body Mass Index, the presence or absence of a television in the child's bedroom, and hours spent watching TV, watching movies, and playing video games. Families were interviewed again two and four years later.
Researchers found that 59 percent of the children in the study had a television in their bedroom. Not surprisingly, the children with bedroom TVs reported greater amount of total exposure to television, movies, and video games. Where things get interesting is that a bedroom TV at year one was associated with higher BMIs at follow-up years two and four, as well as weight gain from years two to four, even when total viewing time was removed from the analyses. In other words, just having a TV in a child's bedroom, regardless of how much that child watched it, predicted weight gain.
Although the study found an association between a bedroom TV and weight gain, it didn't prove cause and effect. For one thing, the study relied on kids and parents reporting about themselves. It's easy for the subjects of a study to report whether or not their bedrooms have TVs, but they might not be so accurate when guessing the total time spent watching TV in a day. So perhaps the results are attributable to how much a child actually sits on his butt watching TV and playing video games.
But the authors also hypothesize that perhaps a bedroom TV increases risk of weight gain regardless of amount of total viewing because children are at risk for viewing at bedtime and therefore not getting enough sleep. Why does sleep matter? Because inadequate amount of sleep is a strong predictor of weight gain in children. Another possible explanation for the study's results is that children with TVs in their bedrooms may be more likely to watch shows with advertising targeted specifically to them, namely food advertising. And when is the last time you saw an ad for broccoli during a kid's TV show?
Even without proof of cause and effect, it seems that a TV in the bedroom doesn't lead to anything helpful for children. It's one more distraction from keeping them from sleeping and this new study suggests that it may be linked to a higher BMI.