Japan-U.S. Comparisons of the Prevalence of Dementia

Hiroko H. Dodge, University of Michigan/Oregon Health & Science University
Gwen Fisher, University of Michigan
Yutaka Kiyohara, Kyushu University
Kenichi Meguro, Tohoku University
Yumihiro Tanizaki, Kyushu University
Kenneth M. Langa, University of Michigan
Teresa Burachio, Oregon Health & Science University

Dementia is strongly associated with disability. For the improved well-being of the elderly and the reduction of overall societal burden caring for the elderly, it is critical to find effective means to prevent dementia. Cross national comparisons on the disease prevalence often shed light on potential risk and protective factors associated with various diseases. Currently Japan holds the highest life expectancy in the world, but whether the Japanese elderly have better cognitive health compared with the elderly in the US is unknown. In this study, we systematically reviewed past literature on the prevalence of dementia in Japan and compared them with the prevalence representative of the US population, which was recently reported by the Aging, Demographics, and Memory Study (ADAMS). Compared with the US, significantly lower prevalence of dementia was found for octogenarians in Okinawa and Hisayama. The potential reasons and implications of the results are discussed.