Prevalence and incidence of dementia in an older Chinese population over two decades: The role of education

Secular trends of dementia prevalence and incidence have rarely been studied in the Chinese population.We examined the changes in dementia prevalence and incidence by comparing data from Shanghai Epidemiological Survey of Dementia and Alzheimer's disease (SESD) and Shanghai Aging Study (SAS) conducted two decades apart.The dementia prevalence and incidence in total participants in SAS were higher than that in SESD (prevalence: 6.44% vs 2.30%, P < .001; annual incidence: 2.58% vs 1.33%, P < .001). In participants with ≤6 years of education, the dementia prevalence in SAS was higher than that in SESD (6.39% vs 3.07%, P < .001); the annual dementia incidence in SAS was double that in SESD (3.63% vs 1.80%, P = .019).We observed an increasing trend of dementia prevalence and incidence in the Chinese elderly, especially those with low education. The dramatic rise in numbers of people with dementia may happen most likely in low-educated populations.