BMJ

Dementia incidence falls but prevalence rises among older adults

May 29, 2025

Study details: This nationwide, population-based study analyzed fee-for-service Medicare beneficiaries aged 66 or older with at least one year of continuous enrollment from 2015 to 2021. The primary outcomes were annual incidence and prevalence of dementia, stratified by age, sex, race/ethnicity, and neighborhood socioeconomic status.

Results: A total of 5,025,039 incident dementia cases were identified. The age- and sex-standardized incidence of dementia decreased from 3.5% in 2015 to 2.8% in 2021, while prevalence increased from 10.5% to 11.8% over the same period. Male beneficiaries had a higher incidence than females, with the gap widening over time. Black beneficiaries had the highest incidence in both 2015 (4.2%) and 2021 (3.1%), though racial/ethnic disparities narrowed during the study period. Socioeconomic disparities persisted.

Clinical impact: The declining incidence alongside rising prevalence suggests improved survival among individuals with dementia or increased duration of disease, amplifying the overall burden on healthcare systems. Persistent disparities by sex, race/ethnicity, and socioeconomic status highlight the need for targeted interventions to promote health equity and address modifiable risk factors in vulnerable populations.

Source:

Blass B, et al. (2025, May 20). BMJ. Incidence and prevalence of dementia among US Medicare beneficiaries, 2015-21: population based study. https://pubmed.ncbi.nlm.nih.gov/40393738/