Risk of dementia is much higher than previously thought

A recent study reveals that Americans who are 55 years of age and older now face an estimated 42% lifetime risk of developing dementia, surpassing older estimates by more than double. 

Dementia, which involves progressive declines in memory, concentration, and judgment, is expected to result in roughly 500,000 new cases in 2025, a figure set to climb to one million cases a year by 2060. 

Researchers explain that this rise is closely linked to the aging U.S. population, along with additional risk factors such as genetic predisposition, high rates of hypertension and diabetes, obesity, poor nutrition, physical inactivity, and mental health challenges.

Why previous estimates were lower

Researchers attribute prior underestimations to inconsistent documentation of dementia in health records and death certificates, inadequate monitoring of early-stage cases, and the underreporting of cases among racial minorities, who are disproportionately affected by the condition.

The findings stem from a large collaborative study funded by the National Institutes of Health, conducted by NYU Langone Health, with contributions from Johns Hopkins University and other institutions. 

The research utilized data from the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS), which has been tracking the vascular and cognitive health of nearly 16,000 participants since 1987. ARIC-NCS is noted for being the longest research effort focusing on cognition and heart health in African-Americans.

Gender and racial disparities

The study’s findings, published in the journal Nature Medicine, detail 3,252 dementia diagnoses among participants from 1987 to 2020, translating to a lifetime risk of 42% for middle-aged Americans.

The results indicate that men face a 35% risk, whereas women face a 48% risk – a difference primarily due to women’s longer average life expectancy. 

The research also pinpoints higher dementia susceptibility among Black adults and among carriers of a particular APOE4 gene variant, recognized as a chief genetic risk factor for late-onset Alzheimer’s disease.

“The relative growth in new dementia cases was especially pronounced for Black adults. These results highlight the urgent need for policies that enhance healthy aging, with a focus on health equity,” noted the researchers.

Dramatic rise in dementia risk

“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 Josef Coresh, who served as senior investigator on the research and is the founding director of the Optimal Aging Institute at NYU Langone. 

Coresh noted that the increase in cases is partly tied to brain function decline starting in middle age, a growing number of Americans over 65, and longer average lifespans among women.

Health concerns linked to dementia risk

The study also reveals that the lifetime risk of dementia surpasses 50% for those reaching age 75. However, previous findings suggest that strategies for preventing heart disease – such as blood pressure control and diabetes prevention – could similarly help reduce cognitive decline.

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

Hearing loss is another critical concern tied to dementia risk, yet only about a third of older Americans experiencing hearing loss use hearing aids. Coresh advocates greater monitoring, expanded testing, and more affordable hearing aids to alleviate this issue.

Racial disparities and broader recommendations

According to Coresh, far more resources are needed to address racial inequities in health care, noting that while dementia numbers among Caucasian individuals are expected to double over the next four decades, rates among Black individuals are expected to triple. 

Health policies should heighten efforts in Black communities to improve childhood education and nutrition, which research has shown to be beneficial for delaying cognitive decline later in life.

Ultimately, these findings highlight the daunting challenges posed by dementia as Americans age, but they also suggest paths for intervention – through robust healthcare systems, preventative heart health measures, support for hearing care, and programs targeted at reducing social and racial inequities.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–