Screen-time battle alone won't cut child obesity

Efforts to get obesity-bound children away from their TV and computer screens likely won't work after the age of six, a new review finds.

Efforts to get obesity-bound children away from their TV and computer screens likely won't work after the age of six, a new review finds.

Canadian children and youth get an average of at least six hours of screen time   a day, according to researchers. Parents are encouraged to reduce this sedentary time to prevent their children from becoming obese.

But a review in Monday's online issue of the Archives of Pediatrics and Adolescent Medicine suggests that attempts to intervene and modify children's behaviour might not be enough. 

Children six years old or younger are more likely to respond than older kids, the review found.

In Canada, children and youth are getting an average of six hours of screen time per day on weekdays. (iStock)

"Looking at children of all age groups, we did not find an overall effect on a measure of obesity, called the body mass index," said Dr. Catherine Birken, senior author of the study and a staff pediatrician at Toronto's Hospital for Sick Children.

The review looked at 13 randomized controlled trials around the world, each with between 21 and 1,295, participants.

The interventions — at the school, community or clinic level — focused on trying to change the children's behaviour. The approaches included teaching them how to budget their screen time and how to replace screen time with other activities.

Children under study were 18 or younger.

Preschooler exception

Among preschoolers below six, interventions had a greater chance of changing behavour. Reductions in screen time were tied to significant reductions in body mass index, or BMI, the review's authors said.

"Interventions in the preschool age group hold promise," they concluded, noting the strategy may be more effective at this age because parents have more control over their kids' lifestyle behaviours.

It's also possible the trials, lasting an average of seven months, were too short to realize any effect from intervention efforts.

To be effective, several interventions need to be made at the same time — at home, at school, in the clinic, in the community and at the policy level, Birken suggested.

At a park in downtown Toronto, Jean Lamantia explained how she limits TV time.

"One rule we have at home is there's no food in front of the TV," said Lamantia, a dietician who has a two-year-old daughter. "If they happen to be watching TV and they say they're hungry, well, the TV has to go off."

The research team is working on developing and testing simple messages to guide parents of young children on healthy nutrition, activity and good health.

The study was supported by the Pediatric Outcomes Research Team and SickKids Foundation.

With files from CBC's Lorenda Reddekopp