Recent figures show that childhood obesity has more than doubled in children and quadrupled in adolescents over the past 3 decades. New research suggests that children who have televisions in their bedroom are more likely to gain weight, compared with those who do not have them in their bedroom.

This is according to a study recently published in the journal JAMA Pediatrics.

The team, led by Dr. Diane Gilbert-Diamond of the Geisel School of Medicine at Dartmouth, Lebanon, NH, states that approximately 71% of individuals aged between 8 and 18 years have televisions in their bedrooms.

Given the high level of exposure to television viewing and gaming, the researchers hypothesized that it could be having a detrimental impact on the weight of children and adolescents.

To see if there was an association, the investigators conducted a telephone survey on 6,522 boys and girls aged between 10 and 14 years.

Participants were asked a series of questions that assessed the presence and usage of bedroom televisions, such as “on school days, how many hours do you spend watching TV?” and “how many hours do you spend playing video or computer games?”

The researchers used sample weights representative of US children aged 10 to 14 years to determine the participants’ weight at the baseline of the study, while their height and body mass index (BMI) was self- and parent-reported 2 and 4 years after baseline.

At the beginning of the study, 59.1% of children reported having a television in their bedroom.

Bedroom televisions were more common among boys and individuals with a lower parental educational level and family income.

Children who reported having a bedroom television also reported a higher exposure to television viewing, video games and movies, compared with those who did not have a bedroom television.

Results of the study revealed that having a television in the bedroom was linked to an excess BMI of 0.57 at 2 years after study baseline and an excess BMI of 0.75 at 4 years after study baseline.

The researchers hypothesize that bedroom televisions may disrupt a child’s sleep pattern. Previous studies have shown that shorter sleep duration may be a cause of subsequent weight gain in children.

Furthermore, they say a bedroom television may increase exposure to child-targeted food advertising.

“Children viewing bedroom televisions might have more control over the programs viewed and might therefore be more highly exposed to advertisements that target their demographic,” the study authors write.

However, the researchers note that since their study did not monitor these associations, they are unable to consider them as a cause of increased BMI in children.

The investigators suggest that removing televisions from children’s bedrooms might be an “important step” in the fight against childhood obesity in the US.

They write:

In contrast to limiting screen time, which may require consistent parental monitoring, removing a child’s bedroom television is a structural change in the child’s electronic media environment that is potentially long lasting.”

The authors add that the American Academy of Pediatrics recommends against children having televisions in their bedroom, and that this study should motivate pediatricians to support these recommendations when talking to patients.

However, the investigators point out that at the time of this study, which began in 2003, televisions were the main form of media exposure for children.

They note that because children are now exposed to media through other types of electronic devices, such as smartphones and laptop computers, further studies should be conducted to assess whether these types of media exposure contribute to weight gain in children.

This is not the first study to associate bedroom televisions with child obesity. In 2012, Medical News Today reported on research suggesting that children who have televisions, computers and other electronic devices in their bedrooms are 28% more likely to become overweight and 30% more likely to become obese.