Prevalence and Incidence of Dementia in South Korea: A Nationwide Analysis of the National Health Insurance Service Senior Cohort

BACKGROUND AND PURPOSE: Dementia is rapidly becoming more common in the elderly population of South Korea, and there are regional difference in its demographics. This study investigated the trajectories in the prevalence and incidence of dementia based on the Seoul metropolitan area and other areas in South Korea using big data from the National Health Insurance Service (NHIS). METHODS: We examined a population-based elderly cohort obtained from the NHIS Senior Cohort (NHIS-SC) data set that comprises approximately half a million recipients of medical insurance in South Korea during 2003–2015. The age-standardized prevalence and incidence of dementia as well as their trajectories from 2003 were estimated. Regional differences in these rates between Seoul metropolitan area and other areas were also analyzed. RESULTS: The standardized prevalence of dementia per 100,000 increased significantly from 178.11 in 2003 to 5,319.01 in 2015 (p<0.001). The standardized prevalence of dementia was higher in other areas than in Seoul metropolitan area. The standardized incidence of dementia per 100,000 person-years also increased significantly, from 126.41 in 2003 to 2,218.25 in 2015 (p<0.001). The standardized incidence of dementia was similarly higher in other areas than in Seoul metropolitan area (p<0.001). CONCLUSIONS: This study has shown that the standardized prevalence and incidence of dementia increased steadily from 2003 to 2015 in South Korea based on the NHIS-SC data set, and differed between Seoul metropolitan area and other areas.