Watching Television Increases Diabetes Risk

For each hour spent watching television daily, the risk of developing diabetes increases by 3.4 percent, after controlling for other important risk factors, according to an analysis by the University of Pittsburgh Graduate School of Public Health. 

The research was published recently by the European Association for the Study of Diabetes journal Diabetologia.  

“Less time spent watching TV per day over a three-year follow-up translated into a lower risk of developing diabetes, even after controlling for how much physical activity people were reporting,” said lead author Bonny Rockette-Wagner, director of physical activity assessment at Pitt Public Health.

When body weight was added to the model, this association was reduced to a 2.1 percent increased risk of developing diabetes per hour of watching TV. This suggests that subsequent changes in body weight may account for some of the relationship between sitting behavior changes and diabetes development.

This investigation by Rockette-Wagner and her colleagues was part of the Diabetes Prevention Program, a clinical research trial funded by the National Institutes of Health. The prevention program trial had previously demonstrated in sites across the U.S. that people at risk for diabetes who lost weight and increased their physical activity levels sharply reduced their risk for diabetes and heart disease, outperforming people who took a diabetes drug when compared to placebo. The Diabetes Prevention Program’s two lifestyle goals were to achieve 150 minutes per week of moderate intensity activity, such as brisk walking, and a seven percent weight loss. The main study results were published in 2002.

Rockette-Wagner, senior author Andrea Kriska of Pitt Public Health, and their colleagues recently analyzed data from the Diabetes Prevention Program to determine whether the lifestyle intervention also reduced time spent sitting. Prior to the trial, watching television and sitting at work, combined, averaged nearly seven hours per day. People who participated in the lifestyle intervention arm of the trial reported reducing their combined television and work sitting time by 37 minutes per day, compared to a six-minute reduction in people taking the diabetes drug and a nine-minute reduction in people taking a placebo.

“This is not always the case, as interventions that succeed in increasing moderate intensity activity do not always result in positive changes in sitting,” Rockette-Wagner said.

“Because a decrease in sitting occurred despite the absence of program goals aimed at reducing sedentary behavior, it is likely that a lifestyle intervention program that incorporates such a goal would result in greater changes in sitting and greater health improvements than we found in this study,” said Kriska, a professor in Pitt Public Health’s Department of Epidemiology. “Future intervention efforts that focus on increasing physical activity and reducing weight also should consider emphasizing sitting less.”

As a next step in the effort to determine the impact of decreasing sedentary behavior, Kriska and her colleagues at Pitt Public Health recently received a $3 million grant from the NIH to test the efficacy of a community-based lifestyle intervention program that focuses on encouraging sedentary, overweight adults to sit less.