ALTHOUGH the incidence of new dementia diagnoses among older Americans has declined in recent years, the overall number of people living with dementia has risen, highlighting a growing need for improved long-term care and support systems, according to a large national study.
Dementia remains one of the leading causes of disability and dependency among older adults, imposing significant burdens on individuals, families, and healthcare systems. In the United States and globally, ageing populations are expected to increase the prevalence of dementia, with projections suggesting more than 150 million people worldwide could be affected by 2050. Understanding current trends in dementia diagnosis and prevalence is essential for planning healthcare services, supporting caregivers, and addressing ongoing disparities that disproportionately impact women, racial and ethnic minorities, and those living in socioeconomically disadvantaged areas.
Researchers analysed data from over 25 million traditional fee-for-service Medicare beneficiaries aged 66 or older with at least one year of continuous enrolment between 2015 and 2021. The study calculated both incidence (new cases per year) and prevalence (total cases at a given time) of dementia, and examined these outcomes across subgroups defined by age, sex, race/ethnicity, and neighbourhood socioeconomic status. During the study period, the age- and sex-standardised incidence of dementia fell from 3.5% in 2015 to 2.8% in 2021, while prevalence rose from 10.5% to 11.8%. By 2021, nearly 2.9 million beneficiaries were living with a dementia diagnosis. The incidence of dementia was highest among Black beneficiaries (3.1% in 2021), followed by White (2.8%) and Hispanic (2.6%) beneficiaries. Disparities persisted, with higher rates among women and those from less affluent neighbourhoods. Notably, while men had a slightly higher age-standardised incidence than women in 2015, by 2021, women’s incidence had declined more than men’s.
These findings indicate that, while fewer older adults are being newly diagnosed with dementia each year, those with the condition are living longer, increasing the overall prevalence and demand for long-term care. For clinical practice, this highlights he importance of developing comprehensive support systems for people living with dementia and their caregivers, particularly in underserved communities.
Reference
Blass B et al. Incidence and prevalence of dementia among US Medicare beneficiaries, 2015-21: population based study. BMJ. 2025;389:e083034
