Decline in the Incidence of All-Cause and Alzheimer's Disease Dementia: a 12-Year-Later Rural Cohort Study in Korea.

Upon comparing the results with those from the earlier cohort study in Yeoncheon, the incidence of all-cause and AD dementia decreased by approximately 40% over 12 years; it has been mainly driven by the increase in the educational level of older adults. The declining time trends of incidence should be taken into account for estimating the future prevalence of dementia in Korea.