Objective: A sedentary lifestyle (excessive sitting) is associated with increased risk of obesity and hypertension, which are significant risk factors for cardiovascular disease. Genetic liability to obesity is also an independent predictor of hypertension risk. This study aimed to investigate the effect of genetic liability to obesity on the prevalence of hypertension across different levels of sedentary time. Design and method: Participants were 208,594 unrelated individuals of European ancestry. Obesity genetic liability was estimated using previously identified genetic variants and their effect sizes for body mass index (BMI), waist-hip ratio (WHR) and waist circumference (WC). Logistic regression was used to examine the association between obesity genetic liability and hypertension (defined as systolic blood pressure > or = 140 mmHg, diastolic blood pressure > or = 90 mmHg, or the use of anti-hypertensive medications) across different levels of sedentary time (measured as the sum of hours per day spent driving, watching TV and using a computer). Results: Increased genetic liability to obesity and increased sitting time were associated with higher likelihood of hypertension. The greatest odds of hypertension was observed in participants with high sitting time combined with increased genetic liability to obesity (OR=1.29; 95% CI = 1.25, 1.33, P <2 x10-16) compared to individuals with low genetic liability and low sitting time. Only WC genetic liability exhibited a significant interaction effect on hypertension, with the effect of genetic liability lower in the low sitting-time group than in the high sitting-time group (P interaction=0.03). Conclusions: Higher sedentary time is associated with increased prevalence of hypertension across all levels of genetic liability to obesity. A combination of high genetic liability to obesity and high sedentary time presents the greatest risk. These findings highlight that sedentary time is independently associated with the likelihood of hypertension, irrespective of genetic predisposition to obesity.
Hezekiah et al. (Fri,) studied this question.