Limiting daily TV time to 1 hour may reduce risk for atherosclerotic heart disease
Key takeaways:
- Watching television for 1 hour or less per day was linked to lower atherosclerotic CVD risk.
- The association was independent of predicted genetic risk for type 2 diabetes.
TV watching in excess of 1 hour per day was associated with increased risk for atherosclerotic heart disease, independent of genetic risk for diabetes, according to new data published in the Journal of the American Heart Association.
“CVD is a global public health threat. To contribute to the prevention of CVD, our team has been working to uncover the relationship between lifestyle factors, genetic susceptibility and the risk for CVD. While conditions like type 2 diabetes and sedentary behaviors — such as prolonged TV viewing — are established risk factors for CVD, there are still important gaps in the current evidence base,” Youngwon Kim, PhD, assistant professor in the School of Public Health, and Mengyao Wang, PhD, recent doctoral graduate, both from the University of Hong Kong, told Healio. “For instance, can genetic predisposition to type 2 diabetes independently predict CV risk? Can we prevent CVD in individuals with a high genetic risk of type 2 diabetes before its onset through lifestyle modification? These questions motivated our analysis. We therefore aimed to provide actionable insights that can further advance strategies for CVD prevention.”
To investigate the relationship between genetic risk for diabetes, TV watching and ASCVD risk, the researchers evaluated nearly 14 years of data from 346,916 white British individuals from the UK Biobank (mean age, 57 years; 45% men).
Participants’ genetic risk for diabetes was estimated using polygenic risk scores weighted with sum of the risk alleles at 138 single-nucleotide polymorphisms, according to the study.
Daily TV watching was assessed via baseline questionnaire in which participants were asked, “In a typical day, how many hours do you spend watching television?” Participants were categorized into one of two groups based on daily TV watching: 1 hour or less per day or 2 hours or more per day; approximately 79% of respondents were in the latter category.
Watching TV and risk for ASCVD
Watching 2 hours or more per day of TV was associated with increased risk for ASCVD, even after adjusting for genetic risk for diabetes and any potential confounders, compared with 1 hour or less of daily TV (HR = 1.12; 95% CI, 1.07-1.16).
The researchers reported no evidence linking high genetic risk for diabetes with ASCVD among individuals who watched 1 hour or less of TV per day.
“The main take-home message from our study is that limiting the amount of time spent watching TV, closely related to everyone’s daily life, should always be treated as one of the main strategies for the prevention of atherosclerotic CV events not only for all individuals but also in individuals whose genetic predisposition to type 2 diabetes is high,” Kim and Wang told Healio.
Moreover, 10-year absolute ASCVD risk associated with high genetic risk for diabetes plus 1 hour or less of daily TV watching was lower than the 10-year absolute risk associated with low genetic risk for diabetes plus watching 2 hours or more of TV per day (2.13% vs. 2.46%).
‘Reducing screen-based sedentary activities’
“In current patient care, we place significant emphasis on preventing CVD among individuals with diabetes, as diabetes is a well-established risk factor for CV health. However, preventing CVD in those with a high genetic risk of type 2 diabetes before its onset has not been elucidated,” Kim and Wang said. “Our findings linking genetic risk for type 2 diabetes to the risk of developing ASCVD suggest that in the future, we could leverage genomic technology in clinical settings, rather than solely as a research tool, to identify people who are genetically predisposed to type 2 diabetes, in terms of preventing or delaying the onset of CVD in individuals at high genetic risk before type 2 diabetes develops.
“In addition to delivering messages to the general public, we also aspire for our findings to inspire further studies that delve into the underlying mechanisms through which reducing screen-based sedentary activities — such as TV viewing — reduces the risk for CVD in individuals at high genetic risk for type 2 diabetes.”
For more information:
Youngwon Kim, PhD, can be reached at youngwon.kim@hku.hk.
Mengyao Wang, PhD, can be reached at kathywg@connect.hku.hk.
Reference:
- Minimal TV viewing may be protective for heart diseases linked to type 2 diabetes. https://newsroom.heart.org/news/minimal-tv-viewing-may-be-protective-for-heart-diseases-linked-to-type-2-diabetes. Published March 12, 2025. Accessed March 12, 2025.
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