Genetic susceptibility, screen-based sedentary activities and incidence of coronary heart disease
Creators: name: Kim, Youngwon
name: Au Yeung, Shiu Lun
name: Sharp, Stephen J.
name: Wang, Mengyao
name: Jang, Haeyoon
name: Luo, Shan
name: Brage, Søren
name: Wijndaele, Katrien
Publisher: name: The Health & Fitness Journal of Canada
Year: 2022

description: Background: Sedentary behavior has been recognized as a strong risk marker of coronary heart disease (CHD). However, whether the association of time spent sedentary with CHD is independent of genetic susceptibility to CHD is currently unknown. Purpose: This study examined the interplay of genetic susceptibility to CHD and two prevalent types of screen-based sedentary behavior (television [TV] viewing and computer use) relative to CHD incidence. Methods: We analyzed data from 374,055 white British participants of UK Biobank without CHD/stroke at baseline. Each individual’s genetic risk for CHD was assessed using weighted polygenic risk scores, calculated by summing 300 genome-wide significant, independent risk alleles, multiplied by their corresponding effect estimates. TV viewing and computer use were assessed through touch-screen questionnaires. CHD incidence (n= 9,562) was adjudicated over a median 12.1-year follow-up (i.e. 4,495,844 person-years). Cox regression models with age as the underlying timescale were fit. Results: Compared with ≥4hours/day of TV viewing, the hazard ratio (HR) of CHD was 0.83 (95% confidence interval [CI]: 0.78-0.89) for ≤1hour/day of TV viewing and 0.93 (0.89-0.98) for 2-3hours/day of TV viewing, after adjusting for all confounders including genetic risk for CHD. The HR of CHD for middle and high genetic risk was 1.45 (1.37-1.53) and 2.08 (1.98-2.19), respectively, compared with low genetic risk, after adjustment for all confounders. Decreased CHD was observed for ≤1hour/day of TV viewing at high and middle genetic risk and 2-3hours/day of TV viewing at low genetic risk: no evidence of multiplicative interaction between genetic risk and TV viewing (p-value: 0.593). Estimates of the population attributable fractions (PAF) suggested that 11.4% (95% CI: 6.8%-15.7%) of the population risk of CHD could be prevented if TV viewing time were reduced from ≥2hours/day to ≤1hour/day. The PAF values were relatively larger for middle-to-high genetic risk than for low genetic risk, although the confidence intervals were wide and overlapping. No evidence of associations was observed for computer use. Conclusions: Reduced TV viewing time was associated with decreased CHD risk independently of genetic risk. Relatively stronger associations were found for lower TV viewing time at high and middle genetic risk. The results suggest that individuals with high genetic susceptibility may receive greater CHD-risk reducing benefits from a given reduction in TV viewing time. Funding: Strengthened Start-up Funds for New Staff at The University of Hong Kong Li Ka Shing Faculty of Medicine. This research has been conducted using the UK Biobank Resource under Application Number 43528.
description: The Health &amp; Fitness Journal of Canada, Vol. 14 No. 3 (2021): Proceedings from the 8th International Society for Physical Activity and Health Congress