Objective: To investigate the distribution of cognitive function in elderly people and to assess the impact of clinical manifestations of atherosclerotic disease on this distribution.
Design: Single centre population based cross sectional door to door study.
Setting: Ommoord, a suburb of Rotterdam, the Netherlands.
Subjects: 4971 subjects aged 55 to 94 years.
Main outcome measure: Cognitive function as measured by the mini mental state examination.
Results: The overall participation rate in the study was 80%. Cognitive test data were available for 90% of the participants. Increasing age and lower educational level were associated with poorer cognitive function. Previous vascular events, presence of plaques in the carotid arteries, and presence of peripheral arterial atherosclerotic disease were associated with worse cognitive performance independent of the effects of age and education. On average the differences were moderate; however, they reflected the net result of a shift of the total population distribution of cognitive function towards lower values. Thereby, they resulted in a considerable increase in the proportion of subjects with scores indicative of dementia.
Conclusions: These findings are compatible with the view that atherosclerotic disease accounts for considerable cognitive impairment in the general population.