Characteristics of the cognitive function transition and influencing factors among Chinese older people: An 8-year longitudinal study.

Background: Cognitive impairment among older people is an important public health problem in developing countries. Therefore, it is necessary to identify the subtypes of cognitive function among older people in China, and explore the transformation patterns and influencing factors.

Methods: Longitudinal data from the China Health and Retirement Longitudinal Study (CHARLS) were used, and included 2140 women and 2049 men aged over 60 years. Latent profile and latent transition analysis (LPA<A) were used to identify subgroups and transitions between the profiles over time. Influencing factors were identified by multinomial logistic regression analysis.

Results: According to the LPA model, three subgroups of cognitive function were identified: Cognitive Impairment, Mild Cognitive Impairment (MCI) and Normal Cognitive Function. Concurrently, >50 % of participants were likely to progress to MCI after seven years, whereas participants with cognitive impairment had a probability of 54.2 % of transitioning to a better cognitive profile. Older adults are less likely to experience cognitive improvement, higher levels of education affect changes in cognition, and having depression are at a lower risk of cognitive decline.

Limitations: Due to the incompleteness of the cognitive assessment and the large time span, there was a certain bias in the classification and analysis of latent cognitive profiles.

Conclusion: This study identified three latent profiles among Chinese older people and showed the stability and heterogeneity. It demonstrated the effects of higher age or levels of education, and depression on changes in cognitive function in older people.