Incidence of dementia over a period of 20 years in a Norwegian population

INTRODUCTION: In Norway, the prevalence of dementia is higher than in demographically comparable, high income countries, but reliable incidence studies are lacking. This study calculated the incidence of age‐specific dementia from 2000 to 2019. METHODS: Participants from The Tromsø Study (n = 44,214) were included. Participants with a dementia diagnosis (n = 2049 cases) were identified. Poisson regression was used to calculate age‐specific yearly and 5‐year incidence rates from 2000 to 2019. RESULTS: The incidence of dementia has decreased from 2000 to 2019. The trend was highly significant for ages of 60–99 years, and was similar for both sexes. DISCUSSION: The incidence of dementia in North Norway has decreased over the past two decades similar to that in Western countries, indicating that the total prevalence is increasing due to an aging population. This decrease of incidence could introduce a reduction in future estimation of dementia prevalence.