Comparative study of the prevalence of dementia in two Sicilian communities with different psychosocial backgrounds

The role of education and psychosocial environment as factors for the development of dementia is controversial. We carried out a comparative study on the prevalence of dementia among persons over 74 years of age in two Sicilian municipalities, Troina and S. Agata Militello, with different psychosocial backgrounds. A two-stage survey was performed for both samples. In stage I the Mini Mental Status Examination (previously validated for the cutoff score with 100% sensitivity and the highest specificity) was used to screen a 50% random sample of persons over 74 years of age. In those referred to stage 2, the diagnosis of dementia was made by a neurologist according to DSM-III R. Three hundred and sixty-five subjects were recruited in Troina and 408 in S. Agata Militello. The minimal estimates of dementia prevalence were 21.9% (21.9% men, 21.9% women) in Troina and 28.4% (26.6% men, 29.6% women) in S. Agata Militello. Although intrasample multiple logistic exact analysis (demented vs. unproven demented) indicated poor formal education and manual occupation as risk factors for dementia, and intersample comparison (Troina vs. S. Agata Militello) showed that these variables were more frequent in Troina, we did not find a higher prevalence of dementia in this community. We discuss this apparently ambiguous result and suggest that psychosocial and cultural variables might be considered multiple interacting factors with different protective or predisposing roles for dementia. Higher or lower risk could then be the result of this complex interaction in different populations.