The incidence of dementia in populations around the globe

This review synthesizes recent advancements in understanding global dementia incidence while recognizing research inequities that hinder accurate estimates, especially among low- and middle-income countries (LMICs) and ethnoracial minorities. We highlight data gaps and outline opportunities to address these inequities, emphasizing the importance of diversity to achieve more reliable estimates.

Dementia incidence varies geographically; however, global estimates remain skewed due to under-representation and underdiagnosis in LMICs and minorities. While evidence from Europe and the USA show declining incidence, this trend is not universal with increases in Japan, Taiwan, and South Korea. Therefore, forecasted estimates assuming stable incidence, leave health systems underprepared. Risk factors like apolipoprotein Eε4 status show population-specific effects with a strong link to dementia incidence in Western but attenuated effects in African populations. Hence, variation in modifiable and protective factors call for country-specific estimates and interventions, based on diverse representative samples.

Recent findings bring into focus the urgent need for high-quality longitudinal representative datasets, especially among under-researched LMICs and diverse ethnoracial groups. Investment into locally led cohort studies, culturally sensitive assessments and harmonization procedures, equitable collaborations, and methodological transparency will improve incidence accuracy, guiding population-specific interventions and public health policy.