Dr. Erica L. Kenney and Dr. Steven L. Gortmaker from the Harvard T.H. Chan School of Public Health studied data from the 2013 and 2015 waves of the Youth Risk Behavior Surveillance System, which included 24,800 adolescents in grades 9-12. The survey gathered data on the following: hours spent on screen devices (including smartphones, tablets, computers, and video games) and watching television, hours of sleep on an average school night, number of sugar-sweetened beverages consumed in the previous 7 days, and frequency of physical activity (at least 60 minutes per day) for the past 7 days.
The researchers found that almost 20% of U.S. adolescents spent more than 5 hours a day on smartphones, tablets, computers, and video games compared with only 8% watching more than 5 hours a day of television. Watching too much television continued to be associated with obesity and poor diet among adolescents. However, the researchers also found that adolescents who spent more than 5 hours a day on screen devices were twice as likely to drink a sugary drink each day and not get enough sleep or physical activity, and were about 43% more likely to have obesity compared with adolescents who did not spend time on these devices.
Although this study cannot conclude definitively that using screen devices is causing higher rates of obesity, the findings are cause for concern. According to Dr. Kenney, “This study would suggest that limiting children’s and adolescents’ engagement with other screen devices may be as important for health as limiting television time.” Until more research is done, clinicians may want to encourage families to set limits for both television and other screen devices.