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

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.