To explore the longitudinal relationship between sleep condition and physical & mental health among Chinese adults and to provide a basis for improving sleep condition and preventing related chronic diseases.

Based on China Family Panel Studies data, sleep condition index was constructed using self-reported sleep time, quality and daytime function. Physiological health was measured using self-rated health, chronic diseases, physical discomfort and BMI values. Mental health was measured using the Center for Epidemiological Studies Depression Scale. 15 187 adults in three periods (T0: 2016, T1: 2018, T2: 2020) were involved. Trend tests, Cross-lagged path models and robustness tests were used in this study.

There was a significant downward trend in the sleep time among Chinese adults (Z=-19.609, P<0.001). The rate of insufficient sleep showed a clear upward trend (Z=-11.542, P<0.001). Sleep quality (Z=8.594, P<0.001) and daytime function (Z=11.045, P<0.001) showed significant deterioration trends. Correlation analysis results showed that sleep condition at three time points was positively correlated with physical health (P<0.001) and mental health (P<0.001). Cross-lagged analysis results showed that T0 and T1 sleep condition positively predicted T1 and T2 physical health [β=0.108(95%CI:0.093-0.122), β=0.078(95%CI:0.063-0.092)] and mental health [β=0.113(95%CI:0.096-0.126), β=0.095(95%CI:0.105-0.136)], T0 and T1 physical health [β=0.111(95%CI:0.096-0.129), β=0.121(95%CI:0.078-0.111)] and mental health [β=0.132(95%CI:0.116-0.149), β=0.139 (95%CI:0.122-0.156)] each positively predicted T1 and T2 sleep condition. The cross-lagged analysis results were robust in subgroups.

There has been a significant and concerning decline in the sleep condition among Chinese adults. There is a bidirectional predictive relationship between sleep condition and physical & mental health across time points.