A Mendelian randomization study on causal effects of leisure sedentary behaviour on the risk of rheumatoid arthritis

Abstract

Background The causal inference between leisure sedentary behaviour (LSB) and rheumatoid arthritis (RA) is still controversial because of potential residual confounding and reverse causality. Methods The present study used publicly available large‐scale genome‐wide association studies (GWAS) of LSB (television watching, computer use, and driving) and RA to perform a two‐sample Mendelian randomization (MR) study to evaluate the causal effect of LSB on the risk of RA. We detected significant causal associations using the multiplicative random effects‐inverse variance weighted (MRE‐IVW) method, the maximum likelihood, robust adjusted profile scores, the weighted median, MR‐Egger regression, and several complementary sensitivity analyses. Risk factor analysis was also conducted to further investigate potential mediators linking causal inference. Results Increased genetic liability to leisure television watching was significantly associated with a higher risk of RA (MRE‐IVW method; OR = 2.46, 95% CI 1.77–3.41; p = 8.35 × 10−8). MR estimates indicated that prolonged leisure computer use was causally associated with a lower risk of RA (MRE‐IVW method; OR = 0.23, 95% CI 0.12–0.46; p = 2.19 × 10−5). However, we found no evidence for a causal effect of leisure driving on the risk of RA (MRE‐IVW method; OR = 0.59, 95% CI 0.10–3.41; p = 0.557). No pleiotropy was detected by the sensitivity analysis. Conclusions This study supports a causal association between prolonged leisure television watching and an increased risk of RA. Additionally, prolonged computer use might be a protective factor for RA.

Relationship between sedentary behavior and endothelial dysfunction in a cross-sectional study in China

“…Leisure sedentary behavior is any waking behavior with an energy expenditure less than 1.5 metabolic equivalents in a sitting, reclining, or lying posture, including sedentary television watching, computer use, and driving, excluding sitting at work ( 36 ). The main cause of vascular endothelial dysfunction due to sedentary sitting is the reduction in muscle activity and the subsequent reduction in energy demand leading to a decrease in peripheral blood flow, causing a decrease in shear stress, which in turn increases vasoconstriction, leading to vascular dysfunction ( 37 ).…”

Physical Activity, Sedentary Behavior, and Osteoarthritis: A Two-Sample Mendelian Randomization Analysis

“…Although some studies ( 7 , 8 ) have shown the protective effect of physical activity in OA, other studies revealed the negative effects of exercise in promoting the development of OA. Sedentary behavior includes sedentary computer use, watching television, and driving ( 9 ). An increase in leisure and sedentary behavior is associated with a higher risk of mental illness ( 10 ) and cancer ( 11 ).…”