Rethinking the dementia diagnoses in a population-based study: what is Alzheimer's disease and what is vascular dementia?

OBJECTIVE: To explore the hypothesis that older adults often are affected by more than one disease, making the differential diagnosis between Alzheimer's disease (AD) and vascular dementia (VaD) difficult. METHODS: Incident dementia cases (n = 308) from a population-based longitudinal study of people 75+ years were investigated. The DSM-III-R criteria were used for the clinical diagnosis of dementia. Data on vascular disorders (hypertension, cerebrovascular and ischemic heart diseases, heart failure, atrial fibrillation, diabetes) as well as type of onset/course of dementia were used retrospectively to reclassify dementias. RESULTS: Only 47% of the AD cases were reclassified as pure AD without any vascular disorder. Among subjects with AD and with a vascular component, cerebrovascular disease was the most common (41%). Only 25% of VaD were reclassified as pure VaD. Further, 26% of the pure AD subjects developed a vascular disorder in the following 3 years. CONCLUSIONS: Both vascular and degenerative mechanisms may often contribute to the expression of dementia among the elderly. Most of the AD cases have vascular involvements, and pure dementia types in very old subjects constitute only a minority of dementia cases.

Aguero-Torres H, Kivipelto M, von Strauss E. Rethinking the dementia diagnoses in a population-based study: what is Alzheimer's disease and what is vascular dementia? A study from the kungsholmen project. Dement Geriatr Cogn Disord. 2006;22(3):244-9.

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Eva von Strauss, PhD
Aging Research Center (ARC), Karolinska Institutet
GÃ¤vlegatan 16
SE-113 30 Stockholm (Sweden)
Tel. +46 8 690 58 47, Fax +46 8 690 59 54, E-Mail eva.von.strauss@ki.se