This study aims to prospectively explore the association between sedentary time and the risk of all-cause mortality in adults based on a cohort from rural areas of China.

The study population included 20,194 adults at baseline (2007–2008) who participated in the Rural Chinese Cohort Study. Cox’s proportional hazard regression model was used to analyze the hazard ratios (HRs) and 95% confidence intervals (CIs) of sedentary time and all-cause mortality, and a restricted cubic spline was used to model the dose-response relation. We also carried out a series of sensitivity analyses to verify the robustness of our main results.

The median follow-up duration was 6 years, with a total of 17,265 participants (response rate 85.5%) followed up, and 1,106 deaths observed. Data for 17,048 participants were analyzed, with the mean age of participants being 52.00. Compared with sedentary time <4 h/day group, the risk of all-cause mortality was significantly increased in the 8–11 h/day (HR=1.27, 95%CI:1.03–1.56) and ≥11 h/ day groups (HR=1.48, 95%CI:1.20–1.84). With increases in sedentary time, the risk of all-cause mortality increased gradually (Ptrend <0.001). For each 1 h/day increase in sedentary time, the risk of all-cause mortality increased by 3% (HR=1.03, 95%CI: 1.01–1.05). Sensitivity analyses showed our main results were consistent.

Prolonged sedentary time increases the risk of all-cause mortality in the adult rural Chinese population. Reducing sedentary time may have important implications for reducing mortality risk.