Prevalence of dementia (%) and its subtype by 10 years age group and by study site.
Age 70–79
Age 80–89
Age 90 and older
Study name/site
Prevalence in percentage (95% CI)
AD/VaD ratio
Prevalence in percentage (95% CI)
AD/VaD ratio
Prevalence in percentage (95% CI)
AD/VaD ratio
(Study years)
(Number of subjects screened)
Number of cases: all subtypes combined/AD/VaD
(Number of subjects screened)
Number of cases: all subtypes combined/AD/VaD
(Number of subjects screened)
Number of cases: all subtypes combined/AD/VaD
Hisayama (1985)
3.41 (1.92–5.56)
AD/VaD = 0.13
19.50 (13.65–26.52)
AD/VaD = 0.75
57.14 (28.86–82.34)
AD/VaD = 2.50
(440)
15/1/8
(159)
31/6/8
8/5/2
Hisayama 992
3.35 (2.00–5.25)
AD/VaD = 0.22
13.39 (9.34–18.37)
AD/VaD = 1.44
46.43 (27.51–66.13)
AD/VaD = 6.00
(537)
18/2/9
(239)
32/13/9
13/6/1
Okinawa (1991-1992)
3.67 (2.32–5.02)
AD/VaD = 0.59
14.93 (10.97–18.89)
AD/VaD = 2.10
36.83 (28.08–45.58)
AD/VaD = 3.66
(1481)*
45/16/27
(619)*
81/42/20
37/22/6
Hiroshima (1992–1996)
5.67 (4.09–7.66)
AD/VaD = 0.93
19.04 (14.97–23.87)
AD/VaD = 2.64
41.67 (26.97–61.50)
AD/VaD = 4.66
(741)
42/13/14
(
75/45/17
25/14/3
Hisayama (1998)
3.99 (2.65–5.76)
AD/VaD = 1.71
16.84 (12.76–21.59)
AD/VaD = 1.92
35.59 (23.55–49.13)
AD/VaD = 3.33
(676)
27/12/7
(
50/25/13
21/10/3
Tajiri (1998)
5.18 (3.80–6.93)
AD/VaD = N/A
22.33 (17.37–28.26)
AD/VaD = 1.50
51.52 (30.00–82.51)
AD/VaD = N/A
(908)
7/3/0#
22/12/8#
(
N/A
Hisayama (2005)
6.86 (5.13–8.94)
AD/VaD = 2.40
27.74 (20.50–29.37)
AD/VaD = 1.84
53.49 (42.41–64.32)
AD/VaD = 1.71
(729)
50/24/10
95/46/25
46/24/14
Ama-cho study (2008)
6.7 (4.12–9.02)
AD/VaD = 1.75
17.8 (14.81–26.41)
AD/VaD = 11.33
41.3 (26.51–61.52)
AD/VaD = 4.50
(432)
29/14/8
49/34/3
24/18/4
AD/VaD: the number of AD cases/the number of VaD cases.
#Based on subsample analysis with MRI results. N/A: sample size is too small to perform the calculation (AD + VaD cases < 5).
*Random sampling was used for screening. reported is not weighted. Prevalence, proportions of subtypes of dementia, and AD/VaD ratio used weighted frequencies to show those of the population at large.