Daily internet time: towards an evidence-based recommendation?

Background: Since 2001, a recommendation of no more than 2 h per day of screen time for children 2 years of age or older was adopted in many countries. However, this recommendation was rarely examined empirically. The goal of the present study was to question this recommendation in today's connected world.
Methods: We used data from the ado@internet.ch survey (spring 2012), a representative sample of 8th graders in the Canton of Vaud, Switzerland (n = 2942, 50.6% female). Internet use, health outcomes, substance use, well-being and socio-demographic characteristics were considered. Bi-variate statistical analyses were performed.
Results: All outcomes were significantly associated with the time spent on internet, more time being associated with a higher prevalence of adverse consequences. Youth spending on average one more hour on Internet per day than the reference category (1.5-2.5 h) did not differ in terms of adverse health outcomes. Differences began to appear on sleeping problems, tobacco use, alcohol misuse, cannabis use and sport inactivity with youth spending between 3.5 h and 4.5 h per day on internet.
Conclusions: This study demonstrates the absence of justification for setting a limit to only 2 h of screen time per day. Significant effects on health seem to appear only beyond 4 h per day and there may be benefits for those who spend less than an hour and a half on internet.