Incidence of dementia and Alzheimer's disease in elderly community residents of south-western France

Abstract

Background: Dementia is a growing problem in developed countries. The aim of this paper is to estimate incidence rates of dementia, Alzheimer's disease and vascular dementia in a community population of South-Western France.

Methods: A sample of 2792 subjects was selected and followed-up 1 year and 3 after the initial screening. At each visit, a standardized questionnaire was administered by trained psychologists. Demented subjects were identified using a two-step procedure. The first step consisted of a systematic screening by the psychologist using DSM IIIR criteria for dementia. In the second step, subjects who fulfilled the DSM IIIR criteria were examined by a neurologist. NINCDS-ADRDA criteria were applied to diagnose Alzheimer's disease.

Results: Incidences of dementia and Alzheimer's disease were estimated at 16.3 and 11.4 per 1000 per year, respectively. Incidence estimates increased with age from 2 per 1000 in subjects aged 65-69 years to 74 per 1000 in subjects > 90 years. Incidence estimates of Alzheimer's disease showed the same increased from 0.7 per 1000 to 66 per 1000. Incidences of dementia and of Alzheimer's disease did not level off with age and were not different between genders.