Putting a television in a child's bedroom may be setting them up for excess weight gain over the next few years, suggests a new study.
Researchers found that children who slept in bedrooms with TVs gained more weight each year over the next few years, than kids without TVs in their rooms.
"It's well known that screen time is related to weight gain, but we specifically wanted to look at whether televisions in the bedroom are related to weight gain," Diane Gilbert-Diamond told Reuters Health.
"We hypothesized that they would be because bedroom television may disrupt sleep and there is a known link between sleep disruption and weight gain," she added.
Gilbert-Diamond is the study's lead author from the Geisel School of Medicine at Dartmouth College in Lebanon, New Hampshire.
She and her colleagues write in JAMA Pediatrics that it's estimated about a third of U.S. children and teens are overweight or obese. Previous studies have also linked TVs in children's bedrooms to an increased risk of being overweight.
The authors also note that about 71 percent of adolescents have TVs in their bedrooms.
"We really hope to help our children get a healthy start in life so that they have the best chance for a healthy future," Gilbert-Diamond said.
For the new study, she and her colleagues used data collected from an ongoing study of U.S. teens.
About 6,500 kids between 10 and 14 years old were recruited in 2003 to take a telephone survey. Those children and teens also answered questions two years later and again four years later.
"This is the first study to look at whether having a bedroom TV led to future weight gain," Gilbert-Diamond said.
About 59 percent of participants reported having TVs in their bedrooms.
Overall, the participants who reported having TVs in their bedrooms had larger increases in their body mass index - a measure of weight in relation to height - after two and four years, compared to those who didn't have TVs in the bedroom.
The difference translates to about one extra pound of weight gain each year among participants with bedroom TVs, Gilbert-Diamond said.
While one additional pound each year may not seem like much, she said those can add up throughout childhood.
"If a bedroom TV is present from an early age, it could lead to substantial weight gain over the course of childhood," Gilbert-Diamond said.
The researchers acknowledge their study cannot say for sure that bedroom TVs lead to sleep problems, which in turn lead eventually to weight gain.
It might also be that participants with bedroom TVs were exposed to more food advertising than those who didn't have TVs in their bedrooms, for example.
"In the future, we'd like to explore other media devices - such as laptops, tablets and smart phones - to see if they relate to weight gain and to test whether bedroom media lead to weight gain through disrupted sleep or other mechanisms," Gilbert-Diamond said.
For parents, she recommends taking the TVs from kids' bedrooms.
"Unlike other parenting strategies that require persistent monitoring and effort, removing a TV from a child's bedroom is a one-time action," she said.