NEW YORK — Watching television, America’s most-popular daily activity after sleeping and working, can raise the risk of diabetes, heart disease and premature death when people do it for too long, according to an analysis of eight studies.
For every two hours of TV viewing, the risk of type 2 diabetes increased 20 percent, the risk of cardiovascular disease rose 15 percent and the risk of early death rose 13 percent, according to the research published this week in the Journal of the American Medical Association.
In the U.S., people watch an average of five hours of television a day, the report found. The findings suggest people reduce their TV viewing in exchange for activities that require more physical exertion to help combat an unhealthy, sedentary lifestyle, researchers said.
“Spending too much time watching TV is bad for health,” said Frank Hu, an author of the report and professor of nutrition and epidemiology at Harvard School of Public Health in Boston, in a June 12 e-mail. “Couch potatoes should be aware of the health hazards of prolonged TV watching habits. Perhaps TV programs or manufacturers should carry a warning label about the health hazards.”
Hu, along with co-author Andres Grontved, a visiting researcher in the Harvard School of Public Health’s Department of Nutrition, analyzed studies from the U.S., Europe and Australia that linked television viewing with an increased risk of type 2 diabetes, cardiovascular disease and premature death.
They found that among a group of 100,000 people, each two-hour increase in television watching per day was associated with 176 new cases of type 2 diabetes, 38 new cases of fatal heart disease and 104 deaths a year. Europeans and Australians spent an average three to four hours watching TV each day, less than Americans.
Lack of exercise, an unhealthy diet and obesity can explain the higher risk of diabetes, cardiovascular disease and death in those who watch television, Hu said.
“Sedentary lifestyle, especially prolonged TV watching, is clearly an important and modifiable risk factor for type 2 diabetes and cardiovascular disease,” Grontved said in a statement. “Future research should also look into the effects of extensive use of new media devices on energy balance and chronic disease risk.”
More than 220 million people worldwide have diabetes and about 90 percent of them have type 2, where the body doesn’t use insulin effectively, according to the World Health Organization. Cardiovascular disease is the No. 1 cause of death worldwide, killing more than 17 million people each year, according to WHO. By 2030, more than 23 million people will die from cardiovascular diseases, mainly from heart disease and stroke, according to the organization.
Jen Brennan, clinical nutrition manager at Lenox Hill Hospital in New York, said in a June 10 telephone interview that people need to balance their TV viewing with good diet and exercise.
“I do believe it comes down to choices people are making in their lives,” said Brennan. “People need to learn to make healthy lifestyle choices. If they’re choosing to incorporate television into their life, they need to be mindful of the way they’re eating and their other activity throughout the day so they maintain balance in their lives.”