An Environmental Change Does Not Affect Dementia Prevalence but Affects Depressive State and Physical Activity: A Trans‐Cultural Study of Japanese Elderly Subjects and Japanese Elderly Immigrants in Brazil

Background:Dementia, depressive state, and physical inactivity, are some of the main topics of geriatric medicine. We previously showed the prevalence of dementia in Tajiri, Miyagi Prefecture, Japan. To investigate the environmental effects, first‐generation immigrants are one of the best samples. Brazil is the country with the largest number of Japanese immigrants. Objective:To evaluate the effects of environment on dementia, depressive state, and physical activity, the Tajiri subjects and the elderly Japanese emigrants from Miyagi Prefecture to Brazil were compared. Methods:The total elderly population in Tajiri and that the elderly members of the Miyagi Association in the São Paulo metropolitan area in Brazil were compared. All data were gathered using a standardized interview covering physical status, cognitive function (Mini‐Mental State Examination, MMSE), and depressive state (Self‐reported Depressive Scale, SDS). Dementia and depression were diagnosed based on the DSM‐IV. Results:Seventy‐six percent of the immigrants perceived their health as being excellent or relatively good, whereas only 56% of Tajiri subjects did so. The percentage of subjects with a history of diabetes mellitus, a lifestyle related disease, was 8.4% in Tajiri and 24.2% in Brazil. In spite of similar prevalences of dementia with slightly different MMSE distributions, the two groups had a different SDS distribution; the immigrants showed lower depressive scores. Conclusion:In spite of environmental changes influencing physical activity and diabetes, cognitive function was not apparently affected. Although the immigrants lives were marked with hardship, their depressive scores were unexpectedly lower than Japanese, probably due to their stronger mental activity.