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TOPLINE:

Individuals with high genetic susceptibility to type 2 diabetes (T2D) who watched television for ≤ 1 hour/day had a lower 10-year absolute risk for atherosclerotic cardiovascular disease (ASCVD) than those with low genetic risk for T2D who watched television for ≥ 2 hours/day.

METHODOLOGY:

• Researchers conducted this cohort study to examine the interplay between genetic susceptibility to T2D, television viewing habits, and the risk for ASCVD.
• They included 346,916 White British individuals (mean age, 56.5 years; 55.4% women) from the UK Biobank.
• Participants were categorised by television viewing time into two groups: ≤ 1 hour/day (n = 71,734) and ≥ 2 hours/day (n = 275,182), with viewing habits assessed via questionnaires at baseline.
• A weighted polygenic risk score for T2D was calculated using 138 genetic variants associated with T2D; the risk score was used to stratify individuals into high, medium, and low genetic risk groups.
• ASCVD events were identified through hospital admission records and death registries over a median follow-up of 13.8 years, during which 21,265 incident cases of ASCVD were identified.

TAKEAWAY:

• Individuals watching television for ≥ 2 hours/day had a 12% higher risk of developing ASCVD (hazard ratio [HR], 1.12; 95% CI, 1.07-1.16) than those watching television for ≤ 1 hour/day, regardless of genetic risk for T2D.
• Medium and high genetic risks for T2D were associated with a 6% and 11% higher risk for ASCVD, respectively, than low genetic risk. However, when television viewing was restricted to ≤ 1 hour/day, neither medium nor high genetic risk for T2D was significantly associated with an increased risk for ASCVD.
• Both multiplicative and additive interactions were observed between T2D genetic risk and television viewing time in relation to ASCVD incidence.
• The 10-year absolute risk for ASCVD was lower in individuals with high T2D genetic risk who watched ≤ 1 hour of television daily than in those with low T2D genetic risk who watched ≥ 2 hours daily (2.13% vs 2.46%).

IN PRACTICE:

"Our study informs clinical trials tailored to individuals at high genetic risk of T2D and lifestyle-modification interventions targeting specific types of screen-based sedentary activities as a preventive measure against ASCVD," the authors wrote.

SOURCE:

The study was led by Mengyao Wang, PhD, School of Public Health, The University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong, China, and was published online on March 12, 2025, in the Journal of the American Heart Association.

LIMITATIONS:

Television viewing time was assessed through self-reported information, potentially introducing reporting bias or underestimation due to social desirability. Additionally, the study population was restricted to UK-based individuals of White British ancestry, which may have limited the generalisability of the findings to other populations. Furthermore, the study did not explore the potential mediating effect of T2D phenotype on the relationship between T2D genetic risk, television viewing, and the incidence of ASCVD.

DISCLOSURES:

The study was supported by the Health and Medical Research Fund Research Fellowship and Seed Grants of the University of Hong Kong Li Ka Shing Faculty of Medicine. Some authors reported receiving research support from the Medical Research Council. The authors declared no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.