Epidemiology of Dementia in Japan

Fig. 1.1

Prevalence of early-onset dementia in terms of 5-year age strata

Oddly, the response rate was exactly the same in two surveys in Japan [1, 2]. It is also worth noting that the estimated number of patients was the same. This is because while EOD is said to be increasing in recent years, the obtained results show that it is in fact nearly the same. Estimates from these two surveys are similar to previously reported results from various countries [4–12] (Table 1.1).

Table 1.1

Comparison of prevalence of dementia per 100,000 in the 30–64 year age group among studies

Authors	Year	Country	Place	Age range	Population at risk	n	Prevalence	Target
Mölsä et al. [4]	1982	Finland	Turku	45–54		10	51.0	All dementia
Mölsä et al. [4]	1982	Finland	Turku	55–64		24	144.0	All dementia
Sulkava et al. [5]	1985	Finland		30–64	6120	2	32.7	Severe dementia
Schoenberg et al. [6]	1985	USA	Mississippi	45–64	5489	1	18.2	Severe dementia
Kokmen et al. [7]	1989	USA	Rochester	45–49		2	77.0	All dementia
				50–54		1	40.0
				55–59		2	86.0
				60–64		5	249.0
Newens et al. [8]	1993	UK	Northern Health Region	45–64	655,800	227	34.6	AD
Ohshiroa et al. [9]	1994	Japan	Tottori	40–64	209,621	100	81.4	All dementia
Ichinowatari et al. [1]	1997	Japan	Five catchment areas	18–64	3,729,706	1203	48.1	All dementia
Ratnavalli et al. [10]	2002	UK	London	45–64	326,019	59	81.0	All dementia
Harvey et al. [11]	2003	UK		30–64	240,766	130	54.0	All dementia
Rosso et al. [12]	2003	Netherlands	Zuid-Holland	30–59	1,435,769	21	1.5	FTLD
Ikejima et al. [3]	2014	Japan	Five catchment areas	18–64	9,370,651	2059	47.6	All dementia