Summary: A new study of over 25 million Medicare recipients found that while dementia incidence in the U.S. is declining, more older adults are living longer with the condition. From 2015 to 2021, new diagnoses dropped from 3.5% to 2.8%, yet prevalence increased to nearly 12%.
The findings underscore a growing need for long-term care infrastructure, caregiver support, and health equity measures. Disparities persist, with higher dementia rates among women, minorities, and those in disadvantaged neighborhoods.
Key Facts:
- Incidence vs. Prevalence: New dementia cases declined, but overall prevalence rose to 11.8%.
- Health Disparities: Black Americans and individuals in poorer areas had the highest dementia rates.
- Longer Lifespan: People with dementia are living longer, increasing long-term care demands.
Source: UNC
A major new study published in The British Medical Journal has found that fewer older Americans are being newly diagnosed with dementia, yet the total number living with the condition is growing—a trend with serious implications for the healthcare system.
The latest research, led by experts at the UNC School of Medicine, Duke University School of Medicine, and University of Texas Southwestern Medical Center, spotlights the urgent need for policies that address disparities in dementia prevention, diagnosis, and long-term support.
“We’re seeing encouraging signs that fewer people are being newly diagnosed with dementia each year,” said Jay B. Lusk, MD, MBA, preventive medicine resident at the UNC Department of Family Medicine and visiting research scholar at Duke University.
“At the same time, people with dementia are living longer than before, which underscores the need for long-term care planning, caregiver support, and equitable dementia care delivery.”
Dementia is already a leading cause of disability and dependency among older adults. Globally, more than 150 million people are projected to develop dementia by 2050.
In the United States, this growing burden will increasingly strain families, caregivers, and the healthcare system—especially in underserved communities.
Researchers analyzed data from more than 25 million traditional Medicare beneficiaries between 2015 and 2021, focusing on trends in dementia incidence and prevalence across age, sex, race/ethnicity, and socioeconomic groups.
They made the following key findings:
- Age- and sex-adjusted incidence of dementia fell from 3.5% in 2015 to 2.8% in 2021.
- At the same time, prevalence rose from 10.5% to 11.8%, with nearly 2.9 million beneficiaries—about 12% of traditional Medicare enrollees—living with a dementia diagnosis by 2021.
- Dementia incidence was highest among Black beneficiaries (3.1%), followed by White (2.8%) and Hispanic (2.6%) beneficiaries in 2021.
- Higher rates of dementia were consistently found in women, racial and ethnic minorities, and people living in socioeconomically disadvantaged neighborhoods.
Funding: This work was funded by the Duke-UNC Alzheimer’s Disease Research Center (ADRC) under award P30AG072958 from the National Institute on Aging. The work was additionally funded by the Alzheimer’s Association under award 24HPE-1287087 and the Duke University Department of Neurology.
About this dementia research news
Author: Kendall Daniels
Source: UNC
Contact: Kendall Daniels – UNC
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Incidence and prevalence of dementia among US Medicare beneficiaries, 2015-21: population based study” by Jay B. Lusk et al. BMJ
Abstract
Incidence and prevalence of dementia among US Medicare beneficiaries, 2015-21: population based study
Objective
To determine the incidence and prevalence of dementia in a nationally representative cohort of US Medicare beneficiaries, stratified by important subgroups.
Design
Population based study.
Setting
Nationwide study between 2015 and 2021.
Participants
Fee-for-service Medicare beneficiaries aged 66 or older with at least one year of continuous enrollment.
Main outcome measures
Incidence and prevalence of dementia, calculated as percentage per person years or percentage of beneficiaries respectively. These metrics were also calculated in key subgroups defined by age, sex, race/ethnicity, and neighborhood socioeconomic status.
Results
A total of 5 025 039 incident cases of dementia were documented from 2015 to 2021. The overall age and sex standardized incidence decreased between 2015 and 2021 from 3.5% to 2.8%.
Prevalence increased during this time from 10.5% to 11.8%. Male beneficiaries had a higher age standardized incidence than did female beneficiaries in 2015 (3.5% v 3.4%), a difference that widened by 2021 (2.9% v 2.6%; estimated difference-in-difference 0.94, 95% confidence interval (CI) 0.94 to 0.95; P<0.001).
Incidence was highest in 2015 for black beneficiaries (4.2%), followed by Hispanic beneficiaries (3.7%) and white beneficiaries (3.4%), and in 2021 for black beneficiaries (3.1%) followed by white beneficiaries (2.8%) and Hispanic beneficiaries (2.6%); the difference between white and black beneficiaries narrowed from 2015 to 2021 (difference-in-difference 0.92, 95% CI 0.91 to 0.93; P<0.001) as did the difference between white and Hispanic beneficiaries (difference-in-difference 0.88, 0.87 to 0.89; P<0.001).
Conclusions
The incidence of dementia decreased from 2015 to 2021, but the prevalence increased. Disparities in these measures by race/ethnicity, sex, and neighborhood socioeconomic status should motivate future measures to promote health equity.
