Among the elderly, the prevalence of Alzheimer's disease and multi-infarct dementia, as opposed to depression, increases steeply with age. The overlap found between dementia and depression may have nosological implications. There could be an effect of lower education levels on psychiatric morbidity, particularly on depression.

Stability of the global prevalence of dementia in the elderly population has been documented. However, the decreased prevalence found in elderly men stimulated environmental hypotheses.

The incidence rate of dementia in this Southern European city was slightly lower than in previous studies in North-West Europe. LTR of dementia and AD seems to be slightly increased with age. The association of illiteracy with higher LTR of AD is intriguing.