Recent research indicates that American individuals over the age of 55 have a 42% chance of developing dementia, which is more than double the figure found in earlier studies.
This increased risk might result in approximately 500,000 new dementia cases this year, potentially escalating to 1 million cases annually by 2060. Dementia is characterized by steadily worsening issues with memory, concentration, and decision-making abilities. The rising number of cases is closely linked to the aging population in the U.S. Other contributing factors to dementia include genetics, high levels of hypertension and diabetes, obesity, poor diet, lack of physical activity, and deteriorating mental health.
The authors of the study suggest that past underreporting of dementia risk may stem from unreliable health records and death certificates, insufficient monitoring of early dementia stages, and the undercounting of cases among racial minority groups who are disproportionately affected.
This extensive study was conducted with funding from the National Institutes of Health and involved collaboration with NYU Langone Health, Johns Hopkins University, and various other U.S. institutions. Researchers utilized data collected from the ongoing Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS), which has monitored the vascular health and cognitive abilities of nearly 16,000 participants since 1987, making it the longest study of cognitive and heart health among African-Americans.
In an article published in Nature Medicine online on January 13, the study found that from 1987 to 2020, 3,252 participants were identified as having developed dementia. This results in an overall lifetime risk of 42% for middle-aged Americans, with men at a 35% risk and women at a 48% risk, largely due to women having longer life expectancies.
The findings also indicated an elevated risk for Black adults and those with a variant of the APOE4 gene, suggesting a risk range of 45% to 60% for this group. This specific variant is considered the most significant genetic risk factor for developing late-onset Alzheimer’s disease.
“Our findings indicate a significant increase in the expected dementia burden in the United States over the next few decades, with one in two Americans predicted to face cognitive challenges after turning 55,” stated senior investigator and epidemiologist Josef Coresh, MD, PhD, also the founding director of the Optimal Aging Institute at NYU Langone.
Coresh, who holds professorships in both the Department of Population Health and the Department of Medicine at NYU Grossman School of Medicine, highlighted that the anticipated rise in dementia cases is partly related to the common observation of gradual brain function decline beginning in middle age, the longer average lifespan of women compared to men, and the fact that approximately 58 million Americans are currently over the age of 65. Another major takeaway from the study is that the lifetime risk of dementia surpasses 50% for individuals who reach the age of 75.
However, prior research, including this study, suggests that initiatives aimed at heart disease prevention, such as managing blood pressure and preventing diabetes, may also help reduce cognitive decline and dementia rates.
“The approaching surge in dementia cases presents significant challenges for health policymakers, who must redirect their focus toward strategies to lessen the severity of dementia cases and increase healthcare services for those affected,” Coresh emphasized.
Additionally, hearing loss in older adults has been associated with a heightened dementia risk, yet only a third of Americans experiencing hearing issues utilize hearing aids. In response, Coresh advocates for enhanced monitoring and testing, along with potential government programs aimed at supporting healthy hearing in the elderly, such as improving accessibility and affordability of hearing aids.
Coresh further stresses the need for greater resources to tackle racial disparities in healthcare, pointing out that while dementia rates among White individuals are projected to double in the next 40 years, the rates among Black individuals could triple. Health strategies should intensify efforts within Black communities to enhance childhood education and nutrition, which research has shown positively impacts cognitive health later in life.
For this recent analysis, researchers utilized ARIC-NCS data and developed their lifetime risk projections based on U.S. Census Bureau information.
The studies received funding from several National Institutes of Health grants, including K24HL152440, K01DK138273, R01AG054787, 75N92022D00001, 75N92022D00002, 75N92022D00003, 75N92022D00004, 75N92022D00005, U01HL096812, U01HL096814, U01HL096899, U01HL096902, and U01Hl096917.
Alongside Coresh, co-investigator Jordan Weiss, PhD, from NYU Langone also contributed to this study.
The lead author of the research is Michael Fang, PhD, from Johns Hopkins University in Baltimore, Md.
Additional co-investigators and authors include Jiaqi Hu, MS; Marilyn Albert, PhD; A. Richey Sharrett, MD, DrPH; and Elizabeth Selvin, MPH, PhD, all from Johns Hopkins; David Knopman, MD, from the Mayo Clinic in Rochester, Minn.; B. Gwen Windham, MHS, MD, and Thomas Mosley, PhD, from the University of Mississippi in Oxford; Keenan Walker, PhD, from the National Institute on Aging in Baltimore; Rebecca Gottesman, MD, PhD, from the National Institute of Neurological Disorders and Stroke in Bethesda, Md.; and Pamela Lutsey, PhD, MPH, from the University of Minnesota in Minneapolis.
