[Cognition function and its influencing factors among people aged 55 and above in 4 provinces of China from 2018 to 2019].

Objective: To analyze the current situation of cognition function of people aged 55 and above in 4 provinces of China, and to explore its influencing factors of demographic characteristics.

Methods: Using the baseline data of the "Community-based Cohort Study on Nervous System Diseases", middle-aged and older populations aged ≥55 years with completed data on demographic and economic factors and the cognitive function scale were selected as study subjects. A total of 5103 subjects were included in the study(male 2294, female 2809, 55-64 years old 1875, 65-74 years old 2197, 75-94 years old 1031). Multi-stage stratified cluster random sampling was adopted, and survey subjects were selected from a total of 32 communities in Hebei, Zhejiang, Shaanxi and Hunan provinces. The baseline data obtained from a face-to-face questionnaire survey was entered using electronic tablets on the spot. Montreal cognitive assessment(MoCA) and activities of daily living scale(ADL) were used to determine mild cognitive impairment(MCI) and its subtypes. Multiple linear regression and multiple Logistic regression model were used to analyze the influencing factors of cognitive function in populations.

Results: Among middle-aged and elderly Chinese populations, the score of overall cognitive function and its sub-domains were 21. 79±6. 17, 11. 20±4. 18(memory), 8. 81±3. 31(execution), 5. 33±1. 76(visual-spatial ability), 4. 53±1. 40(language), 13. 32±3. 98(attention) and 5. 54±0. 95(orientation). The prevalence of MCI and its subtypes were 35. 86%, 4. 57%(amnestic MCI single domain, aMCI-SD), 3. 64%(nonamnestic MCI single domain, naMCI-SD), 6. 68%(amnestic MCI multiple domains, aMCI-MD) and 3. 94%(nonamnestic MCI multiple domains, naMCI-MD). Subjects aged ≥55 years, living in rural areas, or with per capita monthly household income less than 1000 yuan had lower score of overall cognitive function and its sub-domains(P<0. 05), and also had lower prevalence of MCI and its subtypes. The OR of MCI, naMCI-SD, aMCI-MD and naMCI-MD was 2. 38(95% CI 1. 98-2. 86), 1. 54(95% CI 1. 01-2. 34), 2. 30(95% CI 1. 65-3. 20) and 3. 11(95% CI 2. 07-4. 69) respectively in subjects aged ≥75 years versus those aged 55-64 years, and of MCI, naMCI-SD and aMCI-MD was 3. 02(95%CI 2. 48-3. 66), 4. 30(95%CI 2. 69-6. 88) and 2. 62(95%CI 1. 81-3. 79) respectively in those living in rural areas versus those living in city areas. Subjects with higher per capita monthly household income had lower ORs of MCI and its subtypes.

Conclusion: The prevalence rate of MCI among people aged 55 and above in four provinces in China is at a relatively high level. In the studied 4 provinces of China, about 35% of Chinese middle-aged and elderly populations are affected by MCI. The status of overall cognitive function and its sub-domains of subjects aged 75 years and above, living rural areas and with lower per capita monthly household income are poor, and they may have a higher risk of MCI and its subtypes.