Dementia Prevalence of Associated Risks Factors Among Asians in the United States: A Systematic Review

Background. There are ethnoracial disparities in dementia incidence. Prior research is exclusively focuses on dementia prevalence among African Americans and/or Hispanics. Few studies include Asian Americans, often have mixed results, with varying demographics, assessments, and reporting methods across studies.

Our review aimed to answer three research questions: 1) Compared the prevalence of dementia and cognitive impairment among Asian population compared to other races and ethnicities in the US, 2) What are the risk factors associated with the dementia and cognitive impairment 3), how representative are Asians in dementia research?

Methods. The literature was searched using strategies in collaboration with a medical librarian for the concepts including dementia, race or ethnicity, and Asian Americans with related synonyms. The strategies were created using a combination of Boolean terms and keywords, and were executed in Embase.com, Ovid-Medline All, Cochrane Library, Scopus, and Web of Science. To be included in the reviews, studies were required to be peer reviewed and report the prevalence or incidence of dementia among at least one Asian group in the US. Results were were input into Covidence where abstract and title review, full text review, and data extraction process were also independently conducted by two researchers while a third researcher confirmed the result in case of the conflicts.

Results. Out of 518 unique articles, 12 articles were included and compared the rates of Alzheimer’s diseases and related dementia between Asian and other ethnoracial groups (mainly whites). Seven studies found that Asian population has a lower incident ratio, two studies found higher, and two studies found no significant difference. However, none of the studies’ samples were representative. The most representative’s data was Medicare Fee for Service beneficiaries, but the Asian population accounted for 2.48% of the total sample, which is lower than the percentage of Asian population living in the US (currently at 5%) in the US. 10 out of 12 the studies focused on the East Asian American. Only two studies included Filipinos, and some other South Asian countries. In addition, Asian samples tend to have comparable or even higher average education level or income than Whites, which did not reflect of actual Asian population living in the US.

Conclusions and Implications. Our study findings suggest that the Asian population tend to have a lower dementia incidence ratio. However, the Asian samples were not fully representative, and future research needs to incorporate diverse subgroups among Asian population and those within the lower socio-economic status. Moreover, more research on dementia risk factors among Asian population is required to reduce health disparities and implement appropriate healthcare planning.