Risk and future burden of dementia in the United States

Dementia is a growing problem in the aging U.S. population. Wavebreak Media / Shutterstock

Dementia affects more than 6 million Americans and accounts for more than 100,000 deaths each year. Knowing people’s lifetime risk of dementia can lead to improved prevention efforts. It can also inform public health planning by generating projections of future cases.

Previous estimates of lifetime dementia risk in the United States are 11-14% for men and 19-23% for women. But these are based on older data in which dementia wasn’t reliably documented and early-stage cases were often missed. These data were also typically limited to non-Hispanic White populations.

A research team led by Drs. Josef Coresh at New York University Grossman School of Medicine and Michael Fang at Johns Hopkins Bloomberg School of Public Health generated updated estimates of lifetime dementia risk across different subsets of the population. They also projected the number of people who would be newly diagnosed with dementia in the U.S. between 2020 and 2060. Results appeared in Nature Medicine on January 13, 2025.

The team analyzed data on more than 15,000 people from the Atherosclerosis Risk in Communities (ARIC) study. All the people studied were free of dementia at age 55. More than a quarter were Black, and more than half were women. About 31% had at least one copy of the apolipoprotein E4 (APOEε4) gene variant, a major risk factor for Alzheimer’s disease. 

The team primarily relied on in-person evaluations. For participants who didn’t come in person, they used phone-based cognitive assessments. They also examined hospital records and death certificates for dementia diagnoses.

The researchers estimated a lifetime risk of dementia of 42% after age 55, more than double previous estimates. The dementia risk was 4% by age 75 and 20% by age 85, with the majority of the risk occurring after 85. Certain groups had greater risks than others. For example, women had a higher lifetime risk due to survival to older ages, 48% versus 35% in men. People with two APOEε4 copies had a lifetime risk of almost 60%, versus 48% for those with one copy and 39% for those with none.

The team applied their lifetime risk estimates to future population projections from the U.S. Census. They projected that the number of new dementia cases in the U.S. will double over the next four decades, from about 514,000 in 2020 to about 1 million in 2060.

The study suggests that the lifetime risk of dementia may be much higher than previously thought. This highlights an urgent need for policies that promote healthy aging. Interventions targeted toward high-risk individuals could help reduce the societal burdens of dementia.

“The pending population boom in dementia cases poses significant challenges for health policymakers, in particular, who must refocus their efforts on strategies to minimize dementia risk and the severity of dementia cases, as well as plans to provide more health care services for those with dementia,” Coresh says.

—by Brian Doctrow, Ph.D.