TV time tied to death, diabetes risk

Watching more than two hours of television a day can increase the risk of death, Type 2 diabetes and heart disease, a review shows.

Watching more than two hours of television a day can increase the risk of death, Type 2 diabetes and heart disease, a review shows.

The study in Wednesday's issue of the Journal of the American Medical Association analyzed data from several studies on the health effects of TV viewing, "the most prevalent and pervasive sedentary behaviour."

When Dr. Frank Hu of the Harvard School of Public Health in Boston and Anders Grontved of the University of Southern Denmark in Odense, looked at watching two hours of TV per day, they found the risk increased by 1.20 times for Type 2 diabetes, 1.15 times for cardiovascular disease and 1.13 times for all-cause mortality. 
Reducing daily TV watching time by two hours could reduce the number of new cases of Type 2 diabetes in the U.S., researchers say. (Sebastien Nogier/AFP/Getty)

Based on those results, the researchers estimated that, among a group of 100,000 people, reducing daily TV time by two hours could prevent 176 new cases of diabetes, 38 cases of fatal cardiovascular disease, and 104 premature deaths a year in the U.S.

Couch potatoes aren't physically active while sitting in front of the TV, and the time is associated with unhealthy eating, such as consuming junk food, the researchers said.

The studies included in the analysis all had participants who did not have a chronic disease, in order to exclude people who were sicker and might watch more TV and then suffer diabetes, heart disease or premature death.

But it is possible that some participants had undetected disease.

Hu and Grontved noted it is biologically plausible that prolonged TV viewing is associated with the diseases, and several studies have reported links between channel surfing and biological risk factors such as obesity.

Similarly, sedentary time such as sitting during work or while driving are also associated with Type 2 diabetes, heart disease and all-cause mortality.

The researchers called for more study to assess the chronic disease risk of prolonged daily use of new media devices, and to quantify the influence of diet and physical inactivity.

The researchers are funded by the Danish Heart Foundation, Danish Health Fund, the Oticon Foundation, the Augustinus Foundation and the U.S. National Institutes of Health.