Excessive Screen Time Tied to Poor Health Habits in Teens

Marlene Busko

December 20, 2016

In a representative national sample of US adolescents, excessive use of electronic devices (smartphones, tablets, video games, or computers) outside of their use to do schoolwork was associated with having poor health habits that contribute to obesity.

"The results in this study demonstrated the highest odds of several obesogenic health behaviors for adolescents using TVs and other screen devices in excess of 2 hours per day," Erica L Kenney, ScD, MPH, and Steven L Gortmaker, PhD, from the Harvard TH Chan School of Public Health, in Boston, Massachusetts, write in their study, published December 14 in the Journal of Pediatrics.

"This study would suggest that limiting children's and adolescents' engagement with other screen devices may be as important for health as limiting TV time," they continue.

However, this was an observational study, so it cannot show cause and effect, and further research is needed to confirm the findings, they note.

"In the meantime, clinicians may want to continue to encourage families to set limits for both TV and other screen use to promote healthy levels of engagement with screen media," they observe.

Teens Glued to Their Smartphone Screens

A recent survey reported that American teenagers spend an average of 2 hours and 42 minutes a day on their smartphones, 1 hour and 37 minutes on computers, and 32 minutes playing video games, Drs Kenney and Gortmaker write.

Excessive television viewing has been linked with increased consumption of unhealthy food and beverages, shorter sleep, and increased obesity, but little is known about the relationship between use of other electronic devices and poor health habits associated with obesity.

To investigate this, the researchers analyzed data from 24,800 American adolescents who replied to the Youth Risk Behavior Survey conducted by the Centers for Disease Control and Prevention in 2013 and 2015.

The students were asked: "On an average school day, how many hours do you play video or computer games or use a computer for something that is not schoolwork? (Count time spent on things such as Xbox, PlayStation, an iPod, an iPad or other tablet, a smartphone, YouTube, Facebook, or other social-networking tools, and the Internet.)"

They were also asked how many hours they spent watching television.

In addition, they were asked to provide their height and weight and also asked how many hours they slept on an average weeknight; how many times they drank soda or pop excluding diet drinks in the past 7 days; and how often they were physically active for at least an hour in the past 7 days.

Three-quarters of the students were 15, 16, or 17 years old, and the rest were 14 or younger (10%) or 18 or older (15%). There were an equal number of males and females, and they were racially diverse.

About one in five adolescents spent 5 hours or more engaged with their electronic devices, but only eight in 100 spent this much time watching television.

Average Time Watching Television or Using an Electronic Device* on a Weekday

Average time, h Watching television, % of participants Using an electronic device, % of participants
None 17 16
< 1 19 15
1 16 12
2 21 16
3 14 13
4 6 9
5+ 8 20
*Computer, video game, tablet, or smartphone for nonschoolwork

Students who spent 5 or more hours each day using an electronic device (outside of doing schoolwork) were almost twice as likely to have poor health habits as students who did not use these devices.

Odds of Poor Health Habits Among Teens Who Spent > 5 Hours/Day Using an Electronic Devicea

  Odds ratio (95% CI)b P
< 8 h of sleep on a weeknight 1.79 (1.54–2.08) <0.001
> 1 sugar-sweetened beverage/d 1.98 (1.69–2.32) <0.001
< 1 hour of physical activity/d 1.94 (1.69–2.25) <0.001
a. Computer, video game, tablet, or smartphone for nonschoolwork
b. Compared with teens who did not spend time with electronic devices

Students who spent 5 or more hours a day watching television were almost three times as likely to drink soda every day and almost twice as likely to be obese as students who did not watch television.

Odds of Frequent Sweetened-Beverage Consumption, Obesity Among Teens Who Spent > 5 Hours/Day Watching Television*

  Odds ratio (95%CI) P
> 1 sugar-sweetened beverage/d 2.72 (2.23–3.32) <0.001
Obesity 1.78 (1.40–2.27) <0.001
*Compared with teens who did not watch television

"Although further study is needed, families should be encouraged to limit both TV viewing and newer screen devices," Drs Kenney and Gortmaker conclude.

Drs Kenney and Gortmaker declared they have no relevant financial relationships.

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J Pediatr. Published online December 14, 2016. Article


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