Dementia with Lewy bodies according to the consensus criteria in a general population aged 75 years or older

OBJECTIVE: To estimate the prevalence of dementia with Lewy bodies (DLB) according to the consensus criteria in a general population aged 75 years or older. METHODS: The "Kuopio 75+ study" is a population based health survey focused on the clinical epidemiology of dementia and functional capacity among elderly subjects aged 75 years or older. On 1 January 1998, a random sample of 700 subjects was drawn from a total population born before 1 January 1923, living in the city of Kuopio, northeast Finland (n = 4518). The study subjects underwent a structured interview and clinical examination. RESULTS: 601 elderly subjects (86% of the random sample) were examined. A dementia disorder was diagnosed in 137-a prevalence of 22.8% (95% confidence interval 19.4% to 26.2%). The prevalence of DLB was 5.0% (3.2% to 6.7%), comprising 22% of all demented subjects. Probable DLB was diagnosed in 20 subjects (3.3% (1.9% to 4.8%)), and possible DLB in 10 (1.7% (0.6% to 2.7%)). The prevalence of Alzheimer's disease was 10.6% (47% of all demented subjects), of vascular dementia, 5.3% (23%), and of other types of dementing disorders, 1.8% (8%). CONCLUSIONS: In a general population aged 75 years and older, the prevalence of a disorder fulfilling the diagnostic criteria of DLB is half that of Alzheimer's disease and the same as for vascular dementia.