Information on University of Montreal study of youth screen time - March 2008

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Study: Screen Time

A third of teens spend 40 hours a week watching TV and surfing the Net

March 13, 2008
Globe and Mail
By Tralee Pearce

Teenagers are spending an average of 30 hours a week in front of the television and computer screen - double the amount recommended by health officials, according to new Canadian research. And teens living in poorer neighbourhoods are watching more than those living in wealthier areas.

As part of a five-year study of 1,293 Montreal students at 10 different high schools, epidemiologist Tracie Barnett found that the majority of teenagers, 60 per cent, report spending about 20 hours a week watching TV and using the Internet.

One-third were spending closer to 40 hours on average and 10 to 11 per cent were spending between 50 to 60 hours a week. Television still accounts for most of the screen time.

Most health experts agree that two hours of screen time a day - or 14 hours a week - is a good maximum benchmark. Viewing more has been associated with an increased risk of becoming overweight and obese, said Dr. Barnett, who studies the social causes and behaviours that lead to obesity and cardiovascular disease.

"Screen time is really a risk factor in its own right," said Dr.Barnett, of the University of Montreal's department of social and preventative medicine, pointing to studies that have linked reduced screen time to weight loss.

Hours spent online or watching TV aren't simply displacing exercise time, though. "Boys, for instance, report more screen time than girls, but they're also more active," she says, adding that more research needs to be done on how the link works.

Other factors could include the exposure to ads for low-nutrition, high-calorie foods or a tendency to snack while watching. And even when teens are not exercising, they may be doing activities such as household chores or playing with friends.

"Even having a television in your bedroom is associated with a greater likelihood of obesity," she says.

With the number of obese and overweight kids roughly tripling in Canada in the past two decades, Dr. Barnett said it's important to take a deeper look at how a teenager's surroundings may exacerbate matters, especially for girls.

While boys living in disadvantaged areas were two to three times more likely to be at the high end of the screen-time measure, the girls were four times more likely.

Dr. Barnett suggested a number of factors that could be at play, including concerns about neighbourhood safety and limited access to parks and open spaces.

Calgary obesity expert David Lau said the new research reinforces what he sees among the teenagers he treats.

"I'm seeing more and more teenagers affected with all the adult health problems when they become overweight, especially the boys," said Dr. Lau, a professor of medicine at the University of Calgary. Common problems include high blood pressure, high blood fat, cholesterol and fatty livers. "It's almost an everyday phenomenon," he says.

Even a 10-per-cent reduction in screen time would be a start, he said. He agreed with Dr. Barnett's suggestion that, especially with lower-income families, the screen often serves as a "surrogate babysitter."

"To change that means a fundamental change in how we can help vulnerable groups because many of these are parents who are struggling," he said. "Both are working and they may work multiple jobs to make ends meet."

University of Washington pediatrics professor Frederick Zimmerman said it's important to point out that excessive screen time is harmful beyond the obesity risk.

Dr. Zimmerman, co-author of The Elephant in the Living Room: Make Television Work for Your Kids, cautions against too much screen time for teenagers because they may mimic the risky, aggressive or violent content they see on TV and the Internet.

"It's important for academics and experts in this field to send a message that anything more than two hours a day is really too much."


Teens spending too much screen time

Girls in poor neighborhoods most likely to watch TVs or computers, study finds

March 12, 2008
By Randy Dotinga
Health Day News

A new survey reports that teenagers spend far too many hours a week in front of TVs and computers, and those in poor neighborhoods have even more "screen time."

"The take-home message is that we have to find out why some of these kids don't have healthier alternatives in their neighborhoods," said study author Tracie A. Barnett, a researcher at Sainte-Justine Children's Hospital Research Center in Montreal.

While it's possible that kids spend their time at home watching television documentaries and perusing classic novels on their computers, researchers assume that they're not exercising their brains or their bodies. Some studies have suggested a link between TV watching and obesity in children, Barnett noted.

In fact, a study published earlier this month reported that cutting TV and computer time in half helped younger children eat less and lose weight.

To figure out what teenagers were up to, Barnett and her colleagues surveyed 1,293 seventh-grade students from 10 Montreal high schools in 1999 and followed many of them for five years.

The students reported the number of hours they spent watching TV, playing video games, or using computers. The findings were expected to be released Wednesday at the American Heart Associations Annual Conference on Cardiovascular Disease Epidemiology and Prevention, in Colorado Springs, Colo.

Half of the boys and a quarter of the girls reported spending an average of more than 42 hours a week in front of electronic screens. TV was the most common form of screen use, accounting for 85 percent of the time.

Girls who lived in the poorest neighborhoods were five times more likely to spend the most time in front of screens than those in the richest neighborhoods.

The girls in poor neighborhoods "might be more vulnerable to perceptions that their neighborhoods are not safe," Barnett suggested. "It's possible that the boys are a little less affected, and they go out anyway."

Future research will try to determine why there's a link between poverty and time spent in front of screens, Barnett said.

Frederick Zimmerman, an associate professor of health services at the University of Washington and Seattle Children's Hospital Research Institute, said parents in poor neighborhoods face tough choices when they decide whether to send their kids outside, where it might be dangerous, or let them sit in front of electronic screens inside.

"Parents -- particularly those in low-income neighborhoods -- face an agonizing choice between the dangers outside the home and those emanating from the TV screen or computer monitor," Zimmerman said. "Sometimes, it is tempting to believe that the dangers posed by extensive TV or computer use are not real, but they are," he said. "Numerous studies have documented the associations between excessive TV viewing and obesity, smoking, alcohol use, violent and aggressive behavior, tolerance of aggression against women, and poor school performance."

More information

To learn more about kids and TV watching, check kidshealth.org.

SOURCES: Tracie A. Barnett, Ph.D., researcher, Sainte-Justine Children's Hospital Research Center, and assistant professor, Department of Social and Preventive Medicine, University of Montreal; Frederick J. Zimmerman, Ph.D., Child Health Institute, Department of Health Services and Department of Pediatrics, University of Washington, Seattle; March 12, 2008, presentation, American Heart Association's Annual Conference on Cardiovascular Disease Epidemiology and Prevention, Colorado Springs, Colo.