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2015 to 2021 Saw Decrease in Incidence of Dementia

Medically reviewed by Drugs.com.

By Elana Gotkine HealthDay Reporter

FRIDAY, May 23, 2025 -- From 2015 to 2021, there was a decrease in the incidence of dementia, but an increase in prevalence, according to a study published online May 20 in The BMJ.

Beau Blass, M.P.H., from Duke University School of Medicine in Durham, North Carolina, and colleagues examined the incidence and prevalence of dementia in a nationally representative cohort of U.S. Medicare beneficiaries in a population-based study.

The researchers documented 5,025,039 incident cases of dementia from 2015 to 2021. There was a decrease in the overall age and sex standardized incidence between 2015 and 2021, from 3.5 to 2.8 percent. During the same time, prevalence increased from 10.5 to 11.8 percent. Higher age standardized incidence was seen for male versus female beneficiaries in 2015 (3.5 versus 3.4 percent); the difference increased by 2021 (2.9 versus 2.6 percent; estimated difference-in-difference, 0.94). In 2015, incidence was highest for Black beneficiaries, followed by Hispanic and White beneficiaries (4.2, 3.7, and 3.4 percent, respectively); in 2021, incidence was 3.1, 2.8, and 2.6 percent for Black, White, and Hispanic beneficiaries, respectively, with the differences between White and Black and White and Hispanic beneficiaries narrowing from 2015 to 2021 (estimated difference-in-differences, 0.92 and 0.88, respectively).

"The burden of dementia was unequally distributed, with the highest incidence and prevalence of dementia among Black beneficiaries and those living in socioeconomically deprived neighborhoods," the authors write.

Several authors disclosed ties to the biopharmaceutical industry.

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Disclaimer: Statistical data in medical articles provide general trends and do not pertain to individuals. Individual factors can vary greatly. Always seek personalized medical advice for individual healthcare decisions.

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Posted May 2025

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