Cognitive Decline Trajectories and Their Determinants in Middle-aged and Elderly Chinese

<i>Objective</i>: This study examined trajectories of cognitive decline in a large nationally representative sample of middle-aged and elderly people in Chinese during 5 years of follow-up, then, explored the factors that influenced the cognitive function decline. <i>Methods</i>: Data from the China Health and Retirement Longitudinal Study cohort (CHARLS: 2011-2015), were analyzed. Totally, 2379 participants (aged 45 years or older) were included. The Latent Class Growth Analyses (LCGA) were used to identify the potential heterogeneity in longitudinal changes of cognitive function and BMI (Body Mass Index) over the past 5 years. And Logistic Regression models were used to explore the factors affecting cognitive decline. <i>Results</i>: The mean score of baseline cognitive function was 14.14 (SD = 1.33). Three trajectories of cognitive function were identified: High-Slow decline (54.1%), Moderate-stable (34.9%), and Moderate-Rapid decline (10.9%). Maintaining a High BMI, living in urban, having a high level of education, people who drink but less than once a month tends to be associated with better cognitive function, older people with depression are more likely to suffer from cognitive decline. <i>Conclusions</i>: Cognitive function was identified into three trajectories in the Chinese middle-aged and elderly population. BMI, place of residence, alcohol consumption, age and depression were found to be potential determinants of cognitive decline, and these factors, especially the modifiable risk factors, should be controlled in life to reduce the occurrence of cognitive decline.