Prevalence of Alzheimer's disease and other dementing disorders: Assiut-Upper Egypt study.

The aim of this study was to determine the prevalence rate of Alzheimer's disease (AD) and other types of dementias among the population over the age of 60 years in Assiut governorate. A 3-phase cross-sectional population-based study was carried out to screen 2, 000 subjects residing in 11 different locations representing the sociocultural status of the area. We subjected each proband to a modified form of the Mini Mental State Examination test. Subjects scored 21 or less were investigated according to a standardized protocol. We found 90 demented subjects yielding a crude prevalence ratio (case per 100 population over the age of 60) of 4.5. A diagnosis of subtypes of dementia was reached in 83 cases. Prevalence ratios for dementia subtypes were 2.2 for AD, 0.95 for multi-infarct dementia. 0.55 for mixed dementias and 0.45 for secondary dementias. Age-specific prevalence tends to be doubled every 5 years. Occupation, level of education and residence did not affect the prevalence or severity of dementia. Comparison with other studies suggests that dementia of all types is as frequent in Assiut governorate as elsewhere.