Prevalence of Dementia and Mild Cognitive Impairment in the Rural Island Town of Ama-cho, Japan

• Published in: Dementia and geriatric cognitive disorders extra Vol. 2; no. 1; pp. 190 - 199
• Main Authors: Wada-Isoe, Kenji, Uemura, Yusuke, Nakashita, Satoko, Yamawaki, Mika, Tanaka, Kenichiro, Yamamoto, Mikie, Shimokata, Hiroshi, Nakashima, Kenji
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 24-04-2012; Karger Publishers
• Subjects: Alzheimer’s disease; Dementia with Lewy bodies; Epidemiology; Mild cognitive impairment; Original; Original Research Article; Vascular dementia; Vascular dementia; Alzheimer’s disease; Mild cognitive impairment; Epidemiology; Dementia with Lewy bodies; Alzheimer's disease
• ISSN: 1664-5464; 1664-5464
• DOI: 10.1159/000338244

Aims: In order to determine the prevalence of dementia and mild cognitive impairment (MCI), we conducted a population-based study in Japan. Methods: Participants included 924 subjects aged 65 years or older who resided in the town of Ama-cho. In phase 1 of the study, the Mini-Mental State Examination and Clinical Dementia Rating were administered for screening purposes. In phase 2 of the study, the subjects who screened positive were further examined by neurologists. Dementia and MCI were diagnosed by means of DSM-IV and International Working Group on MCI criteria, respectively. Results: By the prevalence date of June 1, 2010, 24 subjects had deceased or lived outside the town. In total, 723 of the remaining 900 subjects received a phase 1 test. In phase 2, 98 subjects were diagnosed with amnestic MCI, 113 subjects with non-amnestic MCI, and 82 subjects with dementia. Of the subjects who did not receive the phase 1 test, 66 subjects were diagnosed as having dementia according to data from their town medical card or the Long-term Care Insurance System. The crude prevalence of amnestic MCI, non-amnestic MCI, and dementia were 10.9, 12.6, and 16.4%, respectively. Conclusion: Consistent with the striking increase in the number of elderly individuals, we report higher prevalence of MCI and dementia in Japan than previously described.