Prevalence of Alzheimer's type dementia in an elderly Arab population

The aim of this study was to estimate the prevalence of dementia of the Alz heimer type (DAT) in an Arab Israeli community. Epidemiological studies of dementia have rarely been reported in Arab populations. The target populati on, aged 60 years or older, comprised 821 persons (362 males) who, on 1 Oct ober 1995, were residents of the rural area of Wadi Ara. These persons were examined for symptoms of dementia (DSM-IV criteria), using a semistructure d questionnaire for collection of demographic and medical data. Age, gender , and education-specific prevalence rates were calculated for this populati on and compared to those obtained in other studies. DAT was diagnosed in 20 .5% of this population. Its prevalence increased steeply with age, from 8% among those younger than 70 years to 33% among those aged 70-79 and 51% amo ng those 80 years or older. Illiteracy was very common in this population, and strongly associated with higher prevalence of DAT (27% vs. 4%, P < 0.00 1). DAT was more prevalent among females than males (25% vs. 15%, P < 0.001 ). However, illiteracy was also significantly more frequent among women (96 % vs. 42%, P < 0.001). After correction for illiteracy, the gender differen ce lost statistical significance. Few women smoked, but among men, the prev alence of DAT in those who smoked was lower as compared to non-smokers (14% vs. 23%, a non-significant difference). These results were confirmed by lo gistic regression wherein DAT was included as the dependent variable and ag e, illiteracy, gender and smoking as independent variables (OR = 2.8, 2.8, 1.2 and 0.7, respectively; P < 0.005 for each, except for smoking). Our fin dings suggest that this population is unique because of extremely high rate s of dementia. While the results support a protective effect of schooling a gainst the development of dementia, other factors (e.g. genetic) must be so ught to explain this high frequency.