The annual incidence of vascular dementia and other dementias: A population-based study in Eastern Finland.

Introduction: Considering the globally growing population and the rising incidence of dementia, it is important to understand the proportion of dementia cases affected by vascular brain disease. We aimed to study the incidence of vascular dementia (VD) and other dementias in a defined population in Finland to better understand VD's contribution to the total incidence of dementias and to assess the sensitivity of their diagnostics.

Methods: We aimed to collect all dementia diagnoses made in Northern Savo, Finland, in 2020. The memory disorder diagnoses were identified using the International Classification Codes 10th Revision (ICD-10) diagnoses codes. Finally, we studied the diagnoses in relation to demographic data, focusing on VD.

Results: The total number of new diagnoses of dementia with a vascular component or vascular alone was 202, with 20 cases attributable to pure VD. The annual incidence of dementias with a vascular component in Northern Savo was 81.4 per 100,000 across the population and 310.8 per 100,000 in the age group of  65. In our study population, 23.8% of all incident dementia cases were associated with vascular disease.

Conclusion: According to our findings, dementia associated with vascular pathology has the second highest incidence after Alzheimer's disease (AD), while pure VD is rarely diagnosed. Our findings align with previous international studies and a recent national registry study. Future studies with a prospective study setting, potentially incorporating extensive neuroimaging, would be critical in further understanding the epidemiology of VD.