Getting older brings with it a number of health risks, including dementia. Now, a new study shows that the risk of developing dementia after age 55 among Americans is significantly higher than previously estimated, with a lifetime risk now pegged at 42%.
This statistic, more than double the figures reported in older studies, translates to an estimated 500,000 new dementia cases in 2025, potentially rising to one million annually by 2060. The study, published in Nature Medicine, highlights the profound impact of an aging U.S. population on the number of dementia cases.
Dementia, characterized by progressive declines in memory, concentration, and judgment, is increasingly linked not only to aging but also to genetic factors and lifestyle-related health issues such as hypertension, diabetes, obesity, poor diet, lack of exercise, and mental health challenges. The study attributes previous underestimations of dementia risk to unreliable documentation and underreporting, particularly among racial minority groups who are disproportionately affected.
The study was conducted by NYU Langone Health, in collaboration with Johns Hopkins University and other institutions. It draws on data from the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS).
Followed 16,000 participants since 1987
This long-term study has monitored the vascular health and cognitive function of nearly 16,000 participants since 1987, making it the longest-followed cohort of African Americans for cognition and heart health.
From 1987 to 2020, 3,252 participants in the ARIC-NCS were documented as having developed dementia, leading to the conclusion that the overall lifetime risk for middle-aged Americans is 42%.
Notably, the risk is higher for women (48%) compared to men (35%), attributed to women's longer life expectancy. The study also found elevated risks among Black adults and individuals carrying the APOE4 gene variant, a significant genetic risk factor for late-onset Alzheimer's disease.
"Our study results forecast a dramatic rise in the burden from dementia in the United States over the coming decades, with one in two Americans expected to experience cognitive difficulties after age 55," said Dr. Josef Coresh, the study's senior investigator and founding director of the Optimal Aging Institute at NYU Langone.
New policies needed?
Coresh emphasized the need for health policies that address both heart disease prevention and cognitive decline, as well as strategies to manage the anticipated increase in dementia cases.
The study also underscores the importance of addressing racial inequities in healthcare, noting that while dementia rates among White individuals are expected to double, rates among Black individuals could triple over the next four decades. Coresh supports enhanced efforts in Black communities to improve education and nutrition, which have been shown to help prevent cognitive decline.
Additionally, the study highlights the link between hearing loss and dementia risk, with only a third of Americans with hearing loss using hearing aids. Coresh suggests increased monitoring and testing, along with potential government assistance programs to make hearing aids more accessible and affordable.
As the U.S. braces for a surge in dementia cases, the study calls for comprehensive health policies that not only mitigate the severity of dementia but also expand healthcare services for those affected. The researchers say their findings serve as a wake-up call for policymakers to prioritize strategies that support healthy aging and address the growing dementia burden.