A study demonstrated that minimal television viewing may help offset the cardiovascular risks associated with genetic susceptibility to type 2 diabetes.
Investigators from The University of Hong Kong found that patients with a high genetic risk for type 2 diabetes who limited their TV viewing to 1 hour or less daily had a lower likelihood of developing atherosclerotic cardiovascular disease (ASCVD) compared with those with a low genetic risk who watched 2 or more hours of television daily.
The study, published in the Journal of the American Heart Association, was one of the first to examine the interaction between genetic risk for type 2 diabetes and sedentary behavior. The investigators analyzed data from 346,916 UK adults of predominantly White British descent, with an average age of 56 years. During nearly 14 years of follow-up, 21,265 of the participants developed ASCVD.
"Type 2 diabetes and a sedentary lifestyle, including prolonged sitting, are major risk factors for [ASCVD]. Watching TV, which accounts for more than half of daily sedentary behavior, is consistently associated with an increased risk of type 2 diabetes and atherosclerosis," said senior study author Youngwon Kim, PhD, Professor at the School of Public Health at The University of Hong Kong in a companion press release from the American Heart Association (AHA).
The investigators calculated a polygenic risk score for each participant based on 138 genetic variants associated with type 2 diabetes. They then categorized participants into genotype–TV-viewing groups combining three categories of genetic risk (low, medium, and high) with two self-reported TV viewing behaviors (≤ 1 hour daily or ≥ 2 hours daily).
The analysis revealed:
- Just 21% of participants reported watching TV 1 hour or less daily, whereas more than 79% reported 2 or more hours of daily TV viewing.
- Regardless of genetic risk for type 2 diabetes, watching TV for 2 or more hours daily was associated with a 12% increased risk of ASCVD compared with watching TV for 1 hour or less.
- Participants with medium and high genetic risk for type 2 diabetes did not show increased risk of ASCVD when TV viewing was limited to 1 hour or less daily.
- The 10-year absolute risk of developing ASCVD was lower (2.13%) among individuals with high genetic risk who watched minimal TV compared with those with low genetic risk who watched TV 2 or more hours daily (2.46%).
"We found that people with high genetic risk for type 2 diabetes may exhibit lower chances of developing [ASCVD] disease by limiting TV watching to 1 hour or less each day. This suggests that less TV viewing could serve as a key behavioral target for preventing [ASCVD] linked to type 2 diabetes genetics," said lead study author Mengyao Wang, PhD, of the School of Public Health at The University of Hong Kong.
Damon L. Swift, PhD, FAHA, Associate Professor at the University of Virginia and Chair of the AHA's Physical Activity Committee, who was not involved in the study, commented: "This study shows that reducing TV watching can benefit both people at high risk for type 2 diabetes and those at low risk. It also highlights how lifestyle choices can improve health. These findings add to the evidence that sitting time may represent a potential intervention tool to improve health in people in general, and specifically for people with a high risk for type 2 diabetes."
The investigators noted that the study's findings cannot be generalized to other populations or individuals living in other countries because the participants were predominantly of White British descent living in the United Kingdom.
"Future strategies and actions to prevent disease and improve health by reducing time in front of the TV and promoting other healthy lifestyle modifications should target broad populations, including those with a high genetic risk for type 2 diabetes," Dr. Wang concluded.