Independent and joint association of physical activity and sedentary behavior on all-cause mortality.

Backgrounds: Physical activity (PA) and sedentary behavior (SB) have been associated with mortality, while the joint association with mortality is rarely reported among Chinese population. We aimed to examine the independent and joint association of PA and SB with all-cause mortality in southern China.

Methods: A cohort of 12,608 China Hypertension Survey participants aged ≥35 years were enrolled in 2013 to 2014, with a follow-up period of 5.4 years. Baseline self-reported PA and SB were collected via the questionnaire. Kaplan-Meier curves (log-rank test) and Cox proportional hazards regression were performed to evaluate the associations of PA and SB on all-cause mortality.

Results: A total of 11,744 eligible participants were included in the analysis. Over an average of 5.4 years of follow-up, 796 deaths occurred. The risk of all-cause mortality was lower among participants with high PA than those with low to moderate level (5.2% vs. 8.9%; hazards ratio [HR]: 0.75, 95% confidence interval [CI]: 0.61-0.87). Participants with SB ≥ 6 h had a higher risk of all-cause mortality than those with SB <6 h (7.8% vs. 6.0%; HR: 1.37, 95% CI: 1.17-1.61). Participants with prolonged SB (≥6 h) and inadequate PA (low to moderate) had a higher risk of all-cause mortality compared to those with SB < 6 h and high PA (11.2% vs. 4.9%; HR: 1.67, 95% CI: 1.35-2.06). Even in the participants with high PA, prolonged SB (≥6 h) was still associated with the higher risk of all-cause mortality compared with SB < 6 h (7.0% vs. 4.9%; HR: 1.33, 95% CI: 1.12-1.56).

Conclusions: Among Chinese population, PA and SB have a joint association with the risk of all-cause mortality. Participants with inadequate PA and prolonged SB had the highest risk of all-cause mortality compared with others.