Playing Call of Duty, tweeting late into the night and unlocking new level on Candy Crush are just some of the possibilities these new smart devices bring to children and adolescents. Researchers Erica L. Kenney, ScD, and Steven L. Gortmaker, PhD, from the Harvard T.H. Chan School of Public Health, set out to see if the time spent on smart devices affects risks of obesity in the nation’s children.

“The use of other screen devices is linked with several aspects of adolescent health and well-being, and TV time is more narrowly linked with diet and obesity,” wrote Gortmaker. “Given that TV exposure appears to impact health behavior largely through exposure to advertising, and other screen devices may impact health and psychosocial well-being through additional mechanisms the broader range of health behaviors associated with other screen devices compared with TV appears consistent with existing literature.”

Analyzing data collected by the Youth Risk Behavior Surveillance System, which included 24,800 adolescents, the researchers measured hours spent with screen devices and watching TV, the average hours of sleep on a school night, number of sugary beverages consumed per week and exercise routines in a week.

The study found 20 percent of adolescents spent more than five hours a day in front of smartphones, tablets and computers while only 8 percent spent more than 5 hours in front of a TV. Adolescents using screen devices were also twice as likely to drink sugary drinks each day, fail to get enough sleep and avoid physical activity. Compared to adolescents who did not spend time on screen devices, those who did use were 43 percent more likely to have or develop obesity.

“TV viewing was associated with daily intake of sugary beverages and obesity among both boys and girls, and with physical inactivity among girls, but, interestingly, TV viewing was actually associated with lower risk of physical inactivity among boys, and possibly lower risk of inadequate sleep,” wrote Gortmaker. “In contrast, higher use of other screen devices, including computers, videogames, smartphones, and tablets, was significantly associated with all obesity risk factors studied for both boys and girls, including sugary beverages intake, sleep, and physical inactivity.”