The association of screen time, television in the bedroom, and obesity among school-aged youth: 2007 National Survey of Children's Health.

The prevalence of childhood obesity has increased over recent decades1 and is a public health challenge because of its associations with several cardiovascular disease risk factors in childhood2,3 and the increased likelihood of adult obesity.4,5 One potential contributor to childhood obesity is time spent with screen media, such as viewing television (TV), videos, or video games. Three potential mechanisms linking TV viewing to weight status have been suggested: (1) TV viewing displaces physical activity; (2) increased dietary energy intake from eating while viewing or from the effects of food advertising; and (3) decreased resting metabolic rate during viewing.6 There are inconsistent results for the first suggested mechanism.6 For the second mechanism, experimental studies have demonstrated direct effects, where TV viewing is positively associated with reported intakes of high-fat foods7 and children who watched TV during 2 or more meals per day reported consuming fewer fruits and vegetables, more salty snacks, and sodas.8 There is little support for the third suggested mechanism.6,9 The American Academy of Pediatrics (AAP) recommends that youth over 2 years of age spend no more than 2 hours each day with screens, and that parents do not place a TV in a child’s bedroom.10 Despite these recommendations, 8 to 18-year-olds spend approximately 7.5 hours per day with media, including TV, computers, video games, and movies; moreover, the majority of this time, 4.5 hours, is spent viewing TV.11 Time spent watching TV is positively associated with obesity prevalence in youth;12 this association is well documented by multiple longitudinal studies13–15 and 2 meta-analyses.16,17 One factor that contributes to children and adolescents’ TV-viewing time is having a TV in their bedroom. Between 1999 and 2009, the prevalence of TVs in children’s bedrooms increased from 65% to 71%.11 In 2009, it was reported that 54% of 8 to 10-year-olds and 76% of 11 to 18-year-olds had a bedroom TV. Furthermore, they found that 8 to 18-year-olds with a bedroom TV watched live TV (ie, regularly scheduled programming) about an hour more per day than those without a TV in their bedroom.11 Other cross-sectional studies have found positive associations between having a bedroom TV and TV-viewing time for youth.18,19 In addition to reporting more TV-viewing time, adolescents with a bedroom TV reported poorer dietary habits and fewer family meals, compared with those who did not have a TV in the bedroom;18,19 however, longitudinal data show varying associations. Saelens et al20 reported that having a TV in a child’s bedroom was associated with increased time spent watching TV when children were younger (ie, 6 years old), but not when the children were older (ie, 12 years old). Another longitudinal study that followed 12-year-olds over a 3-year period found a positive association among boys.21 Neither meta-analysis cited above examined the association of excessive screen time, having a TV in the bedroom, and obesity. In this study, we used data from a nationally representative cross-sectional study and examined sociodemographic and behavioral factors associated with children aged 6 to 17 years who exceeded AAP screen time recommendations on a typical weekday. The presence of a TV in the bedroom was among the behavioral characteristics. After controlling for sociodemographic and behavioral characteristics, we then calculated the odds of obesity among 12 to 17-year-olds for those exceeding AAP screen time recommendations. Our analyses are novel because they examine the effect of exceeding AAP screen time recommendations, having a TV in the bedroom, and risk of obesity, while controlling for other characteristics.