A study published in the journal JAMA Pediatrics found that bedroom TVs were tied to significantly higher BMIs over a period of four years.
The 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 andobesity 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.
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 authors of this study concluded that having a television in the bedroom was a significant predictor of weight gain among adolescents.