Thinking of buying your kid a TV of his or her own for Christmas or Hannukah? Well here's a bit of advice from your friends at the American Journal of Preventive Medicine: Don't. It turns out there is a way to make television even more unhealthy for your children: Put a set in their bedroom.
Research has long established that for kids, more "screen time" is linked to higher rates of obesity. A new study goes further. It finds not only that kids with a TV in their bedroom tend to watch more TV, which in itself should make them fatter, but also: Compared to television watched in, say, a family room, the screen time a kid logs in his or her bedroom is linked, hour-for-hour, to more belly fat, higher triglycerides and overall greater risk of developing heart disease and diabetes.
Take two kids with roughly the same diet and the same level of physical activity: The study published Tuesday found that the one with a TV in his bedroom (and boys are more likely to have them than girls) will have more cardiometabolic risk factors than than the one who has to watch TV in one of his home's common rooms.
For the majority of American households, that advice comes too late. Nationwide, 70% of kids between the ages of 8 and 18 already have a television in their bedroom.
The study's lead author, Amanda E. Staiano a researcher with the Pennington Biomedical Research Center in Louisiana, says she's fine with scotching the hopes of kids wishing to get their own TV this holiday season.
"If this gives parents one more bit of ammunition to say, 'No, you can’t have TV in your bedroom,' I’m OK with that," Staiano says. "If we have fewer obese kids in the world, I’ll be the Grinch."
Staiano suggested that over and above the effects of being parked too long in front of a TV, a television in the bedroom might magnify the box's corrosive effects on a child's health by disrupting sleep patterns and discouraging the practice of family mealtimes. Sleep deprivation -- the likely outcome when screen time trumps shut-eye -- is a known risk factor for obesity and, worse, for metabolic dysfunction. Family mealtimes seem to promote healthier eating and lower obesity rates, not to mention less alcohol, drug and tobacco use by kids.
To conduct the study, Staiano and her colleagues studied 369 children and adolescents between 5 and 18 years old. In addition to asking how much television they watched daily and whether they had a TV in their room, the researchers gave the kids a battery of tests. They measured the kids' waist circumference, blood pressure and fasting triglycerides; ran a full cholesterol panel; and gauged each child's fat mass in two ways to get precise measures of subcutaneous fat, fat accumulated in the belly and around visceral organs, and overall fat-to-lean mass ratio. And they tested each child's fasting glucose level -- a measure of metabolic function. The researchers also had participants estimate their daily physical activity levels of food intake.
Among kids who watched more than two hours of TV a day, those who had a TV in their bedroom were as much as 2 1/2 times likelier than those who did not to be in the top one-quarter of kids in terms of fat mass. That finding held steady even after researchers adjusted for age, gender, ethnicity, physical activity levels and diet. Compared to kids who had to watch TV in a living area of the home, those who had a TV in their room were almost three times likelier to have "elevated cardiometabolic risk," meaning they had three or more unhealthy readings in the panels of medical tests they were given.
Sheer volume of TV time mattered too: Kids who watched five or more hours of TV a day were twice as likely as those who watched less to carry a density of visceral fat that fell in the top quartile.
Vicky Rideout, who has written some of the most detailed studies of children's media exposure and its effects for the Kaiser Family Foundation, said the latest study should strengthen some well established warnings but may miss some newer dangers as well.
"Research has consistently shown better outcomes for kids who don’t have a TV in their bedroom than for those who do, whether we’re talking about obesity, sleep or academic achievement," said Rideout, now an independent consultant specializing in health communication, social marketing and youth and media. Rideout urges parents to "take the TV out of the bedroom." But newer technologies will require a new level of vigilance, she adds. "Keep an eye on your child’s smartphone and computers too, because food companies are now marketing games, websites and mobile apps designed to boost consumption of foods kids should be eating less of, not more of," Rideout said.