Causal relationship between physical activity, sleep duration, sedentary behavior, and hypertension: A Mendelian randomisation study

Background

Lifestyle behaviors may be an important means of preventing hypertension. The causal relationship between physical activity, sleep duration, sedentary behavior, and hypertension remains unclear. The aim of this study was to examine these associations by using Mendelian randomization (MR) analysis.

Materials and methods

Single nucleotide polymorphisms associated with sedentary behavior patterns (including length of mobile phone use, time spent driving, time spent watching television, and time spent playing computer games), duration of walks, sleep duration, and moderate-to-vigorous intensity physical activity (MVPA) at genome-wide significance (P < 5 × 10^–8) were selected as instrumental variables (IVs) from a genome-wide association study. These IVs represented exposure factors in the subsequent analysis. Summary statistics for hypertension were obtained from the FinnGen Biobank study. In MR analysis, inverse-variance weighting (IVW), weighted median, and MR-Egger regression were employed for causal inference. In addition, multivariate MR analysis was applied to explore the potential confounding effects of smoking and education on the causal relationships between exposure factors and hypertension. A mediation analysis was conducted to assess whether body mass index (BMI) and waist-hip ratio (WHR) mediated the associations between exposure factors and hypertension.

Results

The IVW analysis indicated that increased time spent watching television was associated with an increased risk of hypertension (OR: 1.831; 95 %CI: 1.482–2.262; P = 1.99E-08). The multivariate MR analysis demonstrated that the effect of television viewing time on hypertension remained significant after adjusting for smoking. However, after adjusting for education level, no significant association was observed between television viewing time and hypertension. Mediation analysis revealed that BMI and WHR mediated the causal relationship between television viewing time and hypertension. Genetically predicted other sedentary behavior factors, duration of walks, sleep duration, and MVPA were not significantly associated with hypertension.

Conclusion

In conclusion, this MR study revealed that a lifestyle of increased time spent watching television may contribute to an elevated risk of hypertension.