Incidence of dementia in the German Heinz Nixdorf Recall study over 20 years.

Introduction: The aim of the study was to estimate the population-based dementia incidence in Germany over a period of two decades.

Methods: We analyzed data from 4814 participants of the population-based Heinz Nixdorf Recall study (49.8% men, 45-75 years at baseline period 2000-2003), who have been monitored for the occurrence of cognitive decline and dementia. We calculated the cumulative incidence of dementia and its major subtypes and the incidence rate per 1000 person-years over two decades.

Results: During a median follow-up of 18.2 (Q1-Q3: 11.3-20.6) years, a total of 298 participants (6.2%) developed dementia (22.1% Alzheimer´s disease, 23.5% vascular dementia, 15.1% mixed dementia, 9.1% other dementia, 30.2% unspecified). The overall incidence rate was 3.9 per 1000 person-years.

Discussion: Our study is the only current population-based study in Germany that estimates the incidence of dementia. In order to reduce the high proportion of unspecific dementia diagnoses, diagnostics urgently need to be improved.

Highlights: New data on the incidence of dementia in Germany in participants ≥45 years of age.Participants have been monitored for dementia incidence over two decades.The overall incidence in our cohort was 3.9 per 1000 person-years.Many patients had unspecific dementia diagnoses in their medical records.Further diagnostic evaluation should be available for all dementia patients.