All-cause mortality, type 2 diabetes mellitus, and the adherence to the rest-activity rhythm in China in 1989–2015: a longitudinal cohort survey

Substantial evidence exists regarding the health impacts of physical activity (PA) and sedentary behavior (SB). However, the influence of the dynamic interplay between PA and SB remains unclear. Concurrently, the shifts toward inactive lifestyles during economic development in developing countries raise concerns. Therefore, we examined rest-activity rhythm (RAR) associations with health in China. This cohort study included 10686 China Health and Nutrition Survey participants (1989-2015). All-cause mortality was ascertained through household surveys; type 2 diabetes mellitus (T2DM) diagnosis was validated via hospital records. The RAR was quantified in relative amplitude (RLAM) metric that is operationally defined as the proportion of time spent on each activity compared to time spent on sedentary behavior. Participants were allocated into four groups according to the quartile of RLAM. The Cox hazard regression model with time-varying covariates was performed to estimated the hazard ratios (HRs). Over (11.6 ± 7.1) mean follow-up years, 853 deaths and 389 T2DM cases occurred. After comprehensive adjustment for confounders, a lower risk of all-cause ( HR = 0.65, 95% CI : 0.44-0.87) and T2DM ( HR = 0.61, 0.29-0.93) for the third RLAM quartile versus lowest quartile were found. Each 1 increment in continuous RLAM was associated with a 23% reduction in all-cause mortality risk ( HR = 0.77, 95% CI : 0.66–0.91) and a 22% lower T2DM risk ( HR = 0.78, 95% CI 0.62–0.98) independent of age and sex. Restricted cubic splines demonstrated nonlinear exposure-response relationships. Balanced weekly RAR maintenance was associated with reduced all-cause mortality and T2DM risk, and moderated by physiological and socio-economic status. Individuals should eusure weekly time duration of PA greater than SB.