Prevalence and subtypes of dementia in Taiwan: a community survey of 5297 individuals

Abstract

Objective: To study the prevalence rate of dementia in Taiwan, the relative frequencies of its subtypes, and its associations with age, education, gender, and residence location.

Participants: A total of 2753 men and 2544 women from four urban and four rural communities participated. Their age ranged from 41 to 88 years; 28% of them were at least 65 years old. Their education ranged from 0 to 20 years; 27% of them had less than 1 year of formal schooling.

Design: Phase I was a screening survey by trained nurses who administered a Chinese version of the Mini-Mental State Examination, the MMSE-T1, to all participants. Phase II involved the assessment for dementia by neurologists on the 1521 individuals who had scored less than 24 on the 30-point MMSE-T1.

Main results: Thirty-one cases of dementia were identified by the DSM-III-R criteria, including 18 cases of Alzheimer's disease, 10 cases of vascular dementia, and three cases of other dementias. The prevalence rate in individuals aged 65 and over was 2.0%. Aging and illiteracy were associated with higher rates of dementia; gender and residence location made no difference.

Conclusions: The prevalence rate of dementia was low in this Chinese population. Consistent with common findings from other parts of the world, a high rate of dementia was associated with older age and illiteracy, and Alzheimer's disease was the most frequent cause.