The risk for developing diabetes may increase by 3.4% with each hour spent watching television daily, according to data published in Diabetologia.
For the study, the researchers assessed data from the Diabetes Prevention Program (DPP), a study which enrolled 3,234 overweight adults aged at least 25 years in the United States with the goal of delaying or preventing type 2 diabetes in high-risk individuals using a metformin drug intervention or a lifestyle intervention.
Previous data on the DPP indicate that the lifestyle intervention was not only successful in reducing the incidence of diabetes but in achieving weight loss of 7% and 150 minutes of moderate intensity activity per week. However, it remained unknown whether this intervention affected sedentary time.
Researchers sought to answer this question in the current study by evaluating whether the lifestyle intervention not only increased physical activity but also decreased self-reported sitting time. They also examined the effect of sedentary behavior on development of diabetes.
Before the intervention, total time spent watching television was not significantly different — around 140 minutes per day — between the lifestyle intervention, metformin drug intervention and placebo groups. Similarly, daily total of time spent sitting at work plus television time — 410 to 423 minutes per day — did not differ significantly between groups, according to the data.
After a mean 3.2 years of DPP follow-up, results showed that sedentary time decreased more in the lifestyle intervention group than the metformin or placebo groups (P<.05). Those in the lifestyle intervention group also reported a greater reduction in mean television watching time — 22 minutes per day — than those in the metformin or placebo groups (P<.001).
Moreover, participants in the lifestyle intervention group experienced the greatest decrease in mean time spent watching television plus time sitting at work during follow-up, as compared with the placebo and metformin groups (37 vs. 9 and 6 minutes per day).
In investigating the link between sedentary behavior and diabetes incidence, the researchers found that, among all participants combined, the risk for developing diabetes increased by about 3.4% for each hour spent watching television after adjustment for age, sex, treatment arm and time-dependent leisure physical activity (P<.01).
The relationship was attenuated, however, to a 2.1% increased risk for developing diabetes per hour of watching television when time-dependent weight was added to the model. This finding suggests that subsequent changes in body weight may account for some of the relationship between changes in sedentary behavior and diabetes development.
“These findings are particularly noteworthy because a decrease in sitting occurred despite the absence of program goals aimed at reducing sitting,” senior author Andrea Kriska, PhD, MS, of the University of Pittsburgh in Pennsylvania, said in a press release.
“It is likely that a lifestyle intervention program that incorporates a specific goal of decreasing sitting time would result in greater changes in sitting and likely more health improvements than are demonstrated here. Finally, these results should inform future intervention efforts that already focus on goals of increasing activity and reducing weight to also consider emphasizing sitting less.”