[Survey on current status of cognitive function among Chinese elderly people]

To investigate the current status and distribution features of cognitive function among the elderly population of China.

A total of 18 137 subjects aged over 60 years old from 2010 Chronic Non-communicable Disease & Risk Factor Surveillance in China were selected in this study. Questionnaire was used to collect the information about gender, age and health status. The Mini-Mental State Examination (MMSE) was adopted as an instrument to measure the cognitive function of adult who had self-reported memory decline. After performing complex weighted analysis, the current status of cognitive function and the prevalence of cognitive disorder were compared by different genders, age groups, urban/rural and education levels.

Among the 18 086 subjects, the median of MMSE sore was 23. The score was higher in males (25) than in females (22) and it was higher in urban (25) than in rural area (22). The cognitive function declined with age increasing. The group of people aging 60-64 years old had the highest score (26), and the group of people aging ≥ 80 years old had the lowest score (19). The MMSE score rose up with education level increasing, the group of people with education level above middle school had the highest score (28) and the group of illiterate people had the lowest score (20). The prevalence of overall cognitive disorder was 10.12% (95%CI: 8.22%-12.02%). The female prevalence (12.45%, 95%CI:9.95%-14.94%) was higher than male prevalence (7.68%, 95%CI:5.94%-9.43%). The group of people aged 60-64 years old had the lowest prevalence (4.69%, 95%CI:3.40%-5.98%), and the people aged ≥ 80 years old had the highest prevalence (22.43%, 95%CI:17.80%-27.05%). The prevalence increased with age increasing (χ(2) = 320.02, P < 0.01). The prevalence of cognitive disorder in illiterate group was 14.6% (95%CI:12.01%-17.23%), and it was separately 6.92% (95%CI: 5.21%-8.64%) and 3.99% (95%CI: 2.58%-5.40%) in group of people with education background of primary school and middle school. The prevalence decreased with education levels increasing (χ(2) = 156.49, P < 0.01). Married or cohabiting elderly people had the lowest prevalence (8.51%, 95%CI: 6.58%-10.43%), lower than single ones (9.32%, 95%CI: 4.00%-14.64%) and divorced ones (14.89%, 95%CI: 12.37%-17.50%). The prevalence of cognitive disorder among rural population (12.16%, 95%CI: 9.51%-14.82%) was higher than it among urban population (5.93%, 95%CI: 4.78%-7.07%). The prevalence in central area (13.57%, 95%CI: 8.55%-18.58%) was higher than that in east (7.96%, 95%CI: 6.17%-9.74%) and west region (9.50%, 95%CI: 7.62%-11.38%) of China. The difference was statistically significant (χ(2) = 54.55, 29.76, 8.81 respectively, P < 0.05).

The prevalence of cognitive disorder among the elderly people over 60 years old was age-related and varied by different gender, marriage status, educational status and the regional distribution.