Objective To investigate the changing trend and epidemiological characteristics of the incidence and mortality of chronic kidney disease (CKD) with age, period and birth cohort in Chinese population. Methods Based on the data of incidence and mortality of CKD in Chinese population aged 20-80 years from 1990 to 2019 in GHDx database, joinpoint regression model was used to analyze the incidence and mortality trend of CKD. An age-period-cohort model was constructed to analyze the effects of age, period, and birth cohort on the trend of CKD incidence and mortality. Results Joinpoint regression analysis showed that the standardized incidence rate of chronic kidney disease in Chinese population increased from 146.37/100 000 in 1990 to 161.52/100 000 in 2019, while the standardized mortality rate decreased from 12.98/100 000 in 1990 to 11.23/100 000 in 2019. The APC model analysis showed that the risk of CKD incidence and death in the Chinese population increased with age, while the risk of CKD incidence increased with the increase of period. The risk of death did not change significantly with the increase of period. The cohort born later had a lower risk of CKD incidence and death compared to the cohort born earlier. Conclusion At present, the age effect and period effect of the incidence and death risk of chronic kidney disease in China are dominant. It is important to take effective measures and intervene in a timely manner, especially to strengthen the protection of older high-risk groups born earlier.

Objective　To explore the mediating role of cognitive function in the association between literacy level and depressive symptoms in middle-aged and elderly people in China. Methods　 Using the fourth national follow-up data of the China Health and Elderly Care Tracking Survey 2018, 8 124 middle-aged and elderly people aged 45 years and above were included as the study subjects. The PROCESS 4.0 program was used to test the mediating effect of cognitive function between literacy level and depressive symptoms, and the Bootstrap method was used for the mediator variable validation. Results The detection rate of depressive symptoms among middle-aged and elderly people in China was 38.10%. After controlling for gender, place of residence, marital status, smoking, alcohol consumption, and exercise, literacy level was a negative predictor of depressive symptoms in middle-aged and elderly people (β =－0.480, t =－11.248, P<0.001). Cognitive function accounted for 58.75% of the amount of mediating effect between literacy level and depressive symptoms. Conclusion 　Literacy level and cognitive function are associated with depressive symptoms in middle-aged and elderly people. Literacy level can influence depressive symptoms directly or indirectly through the mediation of cognitive dysfunction.