[Epidemiological research on dementia in developing countries].

As the world population is ageing, dementia becomes an important public health problem, particularly in developing countries. Epidemiological research in these settings is scarce and present additional methodological difficulties, mainly regarding the socio-cultural adequacy of instruments used to identify cases of dementia. As a result of these concerns the 10/66 Dementia Research Group was founded to fill this gap. This is an international network of investigators, mostly from developing countries, and the group's name was based on the paradox that less than 10% of the population-based studies on dementia are directed to 2/3 or more cases of people with dementia living in developing countries. The aim of the paper is to update data in the literature regarding the differences in dementia prevalence and incidence seen in developed and developing countries.