While fewer Americans are being newly diagnosed with dementia, more are living with the condition—especially in marginalized communities. A recent study of over 5 million Medicare beneficiaries from 2015 to 2021 found that although dementia incidence declined from 3.5% to 2.8%, prevalence rose from 10.5% to 11.8%.
Black Americans consistently had the highest incidence rates, with 4.2% in 2015 and 3.1% in 2021, compared to 2.8% for white and 2.6% for Hispanic beneficiaries in 2021. The study also revealed that people living in socioeconomically deprived neighborhoods experienced the highest rates of both new and existing dementia cases.
Researchers, including Jay Lusk, MD, of Duke University, noted that nearly 4.5 million Medicare beneficiaries were likely living with dementia in 2021. They emphasized that “marginalized minorities are under-represented in Medicare fee-for-service numbers,” suggesting that the actual disparities may be even greater.
In an accompanying editorial, Sara Ahmadi-Abhari, MD, and Carol Brayne, MD, warned that better health monitoring and earlier diagnoses in more advantaged groups could mask the true extent of socioeconomic inequalities. They also pointed to regional clustering and disparities in access and quality of care as factors that complicate the data.
Lusk highlighted that dementia rarely occurs in isolation. “More than 40% of people with dementia have cerebrovascular disease, 30% have depression, and more than 80% have hypertension,” he wrote, underscoring the compounding health burdens faced by these patients.
See “More Americans Have Dementia, Despite Fewer New Cases” (May 20, 2025)