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Prevalence of Dementia and Distribution of ApoE Alleles in Japanese Centenarians: An Almost‐Complete Survey in Yamanashi Prefecture, Japan
Author(s) -
Asada Takashi,
Yamagata Zentaro,
Kinoshita Toru,
Kinoshita Akemi,
Kariya Tetsuhiko,
Asaka Akio,
Kakuma Tatsuyuki
Publication year - 1996
Publication title -
journal of the american geriatrics society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.992
H-Index - 232
eISSN - 1532-5415
pISSN - 0002-8614
DOI - 10.1111/j.1532-5415.1996.tb02431.x
Subject(s) - medicine , dementia , gerontology , apolipoprotein e , allele , demography , genetics , disease , gene , sociology , biology
OBJECTIVE : To determine the prevalence and types of dementia in centenarians and to examine whether the ApoE 4 allele has significant impact on the development of Alzheimer's disease (AD) in the population. DESIGN : Cross‐sectional study and a 6‐month prospective study. SETTING : Yamanashi Prefecture, Japan PARTICIPANTS : Forty‐seven centenarians participated in the study to determine the prevalence and types of dementia. Thirty‐three of the 47 participated in the study of ApoE genotyping. As controls, 224 demented older adults participated in the genetic study. Their age at onset was <90 years. OUTCOMES : Prevalence of dementia based on DSM‐III‐R; types of dementia based on NINCDS‐ADRDA and ICD‐10; distribution on ApoE alleles in the centenarians and in the controls; and the 6‐month mortality rate of the subjects. MAIN RESULTS : Of 47 centenarians, 70.2% had dementia, and AD accounted for the majority (75.8%) of the dementia cases. The distribution of ApoE alleles in all the subjects and the AD subjects was ε2: 4.6% vs. 0%; ε 3: 90.1 % vs. 94.1%; ε 4: 4.6% vs. 5.9%. The frequency of the ε 4 allele in the AD patients showed a tendency to decrease with increasing age, ranging from 38% for those with an age at onset of <60 years to 22% for those with an age at onset of ranging from 80 to 89 years. The 6‐month mortality rate was 27% (9/33) for the demented centenarians, whereas none of the 14 nondemented centenarians died. CONCLUSION : This almost‐complete survey, conducted in a prefecture of Japan, revealed a high prevalence of dementia in centenarians. The ApoE ε 4 allele does not have an impact on the development of AD in centenarians. J Am Geriatr Soc 44:151–155, 1996 .