With the general longevity of Japanese Americans, the prevalence of dementia, both diagnosed and undiagnosed, appear to be increasing with age and assimilation. Among some Japanese, there may be a reluctance to report alterations in mental status or acknowledge changes in behavior.

In one Honolulu-Asia Aging Study (HAAS), the prevalence of vascular dementia among Japanese-American men appeared to be higher than that of White men. The prevalence of Alzheimer’s disease, however, was the same except when compared to their counterparts in Japan, in which case residing in Japan conferred a lower prevalence (White et al, 1996). Among Japanese American men in Hawaii, age 71 and older, the prevalence of Alzheimer’s disease was 5.4% and 4.2% for vascular dementia (Yeo et al, 2006). For the population of Japanese Americans age 65+ in King County, Washington, the prevalence was 4.46% for Alzheimer’s and 1.85% for vascular dementia (Yeo et al, 2006).

Several HAAS studies have examined relationships between such factors such as diabetes, hypertension, cigarette smoking, body weight, serum cholesterol, social engagement, physical activity and function, midlife dietary intake of antioxidants, and midlife C-reactive protein among many others with dementia (Curb et al, 1999; Pelia et al, 2996; Tyas et al, 2003; Stewart et al, 2005; Stearet et al, 2007; Saczynski et al, 2006; Taaffe et al, 2008; Laurin et al, 2004; Laurin et al, 2008). The Kame Project of Seattle has also examined factors such as alcohol and consumption of fruit and vegetable juices with cognitive changes (Bond et al, 2005; Dai et al, 2006).