Emerging trends in cognitive impairment and dementia among older populations in Asia: A systematic review.

Background: Dementia and cognitive impairment rates in Asia have significant policy implications. Contrary to the existing literature, which primarily focused on the Western region, in this study, we provide novel insights into previously unexplored geographical contexts. We aimed to evaluate the prevalence of cognitive impairment and dementia in Asia. Methods: Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, we searched six bibliographic databases: Web of Science, Medline, Science Direct, Ovid, Google Scholar, and PubMed. We targeted cross-sectional studies on dementia and cognitive impairment in Asia, published between 2019-23. Results: Our extensive search yielded 2593 original articles, of which 39 met eligibility criteria. This selection unveiled a significant rise in dementia and cognitive impairment prevalence in Asia, aligning now with trends observed in Western countries - a novel finding that challenges previous assumptions about regional prevalence disparities. The studies predominantly conducted in East Asia (n = 29), along with limited research from Southeast (n = 2), South (n = 7), and Central Asia (n = 1), underscore the geographical gaps in current research. This shift in prevalence patterns is potentially linked to demographic changes, urbanisation, environmental factors, ethnic diversity, and neuroimaging advancements. Identifying modifiable risk factors associated with dementia in these regions presents new avenues for prevention and intervention strategies. Conclusions: Current dementia research in Asia is concentrated in East Asia, with limited data from Southeast, South, and Central Asia. Comprehensive studies across all parts of Asia are crucial to establishing robust data collection methods and identifying modifiable risk factors. This can help manage and mitigate the growing burden of dementia in these societies.