By the time they reach adolescence, many children have a television in their bedroom. These bedroom TVs might reveal something about their weight.
A recent survey of youth looked at the link between having a TV in the bedroom and weight gain over four years.
More than half of youth surveyed had a television in their bedroom.
The researchers found that bedroom TVs were tied to significantly higher BMIs over a period of four years.
Diane Gilbert-Diamond, ScD, of the Department of Community and Family Medicine in the Geisel School of Medicine at Dartmouth College, led this study.
According to Dr. Gilbert-Diamond and colleagues, 11 million children and adolescents are overweight or obese.
Being overweight or obese can increase the risk of other health problems like type 2 diabetes, high blood pressure and sleep apnea.
Dr. Gilbert-Diamond and team noted that previous studies have suggested a link between television viewing time and adolescent weight gain.
This study looked at the link between having a television in an adolescent's bedroom and weight gain.
The researchers conducted a random telephone survey of 6,522 boys and girls aged 10 to 14 years at the start of the study. Almost half of the teens originally surveyed were female.
A total of 4,575 of the original subjects were available for follow-up after two years and 3,055 were available for a four-year follow-up.
The teens were asked about their weight and height to calculate their body mass index (BMI). BMI is used to determine if someone is a healthy weight, overweight or underweight. In adults, a healthy BMI is typically considered to be between 18.5 and 24.9, while overweight falls between 25.0 and 29.9 and obesity is 30 and above.
The researchers also asked each teen whether he or she had a TV in the bedroom and how long they played video games and watched TV each day.
The teens also told the researchers if they played sports.
At the start of the study, 59.1 percent of youth reported having a television in the bedroom. Boys were 8 percent more likely than girls to have a bedroom television.
The researchers also found that having a bedroom television was tied to a watching more television per day and movies per week.
At the two-year follow-up, having a bedroom television was associated with an average of 1.16 larger BMI. At the four-year follow-up, that difference jumped to 1.31.
Average television viewing time was also linked to a higher BMI at two- and four-year follow-ups.
The effect of a bedroom television on BMI was independent of how much the teens watched television.
The authors of this study concluded that having a television in the bedroom was a significant predictor of weight gain among adolescents.
These authors reported that each hour of television viewing per day predicted an average excess BMI gain of 0.14. They suggested that televisions may promote inactivity and disrupt sleep patterns.
Additionally, the authors noted that children with bedroom televisions may have more exposure to child-targeted food advertising.
Lastly, the researchers suggested that removing bedroom televisions could be an important step in fighting childhood obesity.
"The findings in this study represent the state of our country as a whole," said Rusty Gregory, a certified wellness coach and dailyRx Contributing Expert.
"The distractions we allow to interfere with our self-care, be it TV, computer or video games, are wreaking havoc on our weight and health. Limiting these attention grabbers to only a short period of time during the day and removing all TVs from children's bedrooms can have a profound effect on not only our adolescents' health, but for our country as a whole," Gregory said.
This study was published in JAMA Pediatrics on March 3.
The research was supported by grants from the National Institutes of Health. The researchers disclosed no conflicts of interest.