Dementia has been established as one of the major challenges of society. Dementia places an increasing burden on caregivers, and on health care and social welfare. The purpose was to determine the prevalence of dementia syndrome in an ageing rural population, and on the grounds of the results to discuss the development of the prevalence taking into consideration population ageing.

A total population based clinico-epidemiological study was carried out covering all of the 1680 inhabitants aged 60+ in the rural municipality of Haapajärvi in Northern Finland. Registers of health and social welfare, and population interviews using Mini Mental State Examination followed by clinical examinations for those scoring less than 25 points, were used for screening and diagnosing dementia, which was made according to the DSM-IV criteria.

Among all eligible subjects, 70.8% were participating in the study. The prevalence of dementia was 8.8% in a total population aged 60+. The prevalence was associated with advanced age giving the prevalence-rate of 43.8% among the people aged 90+.

The systematic auditing for dementia among the total population of people aged 60+ discovered new cases yielding higher prevalence numbers than found earlier in Finnish or in European studies.

The results refer to the fact that active measures are needed in order to improve the access to diagnostics and care for the demented. Assuming no changes in mortality, and that no effective prevention strategies or curative treatment take place, the number of demented persons in the study area will increase due to the population development by 39% by the year 2020, and by 90% by the year 2030.