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In a nutshell
- Risk factors for Alzheimer’s disease are linked to cognitive function as early as ages 24-34, decades before symptoms typically appear
- Higher cardiovascular risk scores and certain inflammatory markers were associated with lower cognitive performance in young adults
- The findings suggest prevention strategies should begin much earlier in life, potentially changing how we approach Alzheimer’s disease
NEW YORK — Most of us think about Alzheimer’s as a problem for our golden years. But new research delivers a wake-up call – your brain health at 25 might forecast your memory at 75.
Scientists at Columbia University Mailman School of Public Health and the Columbia Butler Aging Center have uncovered evidence that the same risk factors linked to dementia in older adults can affect brain function in people as young as 24. Their findings, published in The Lancet Regional Health – Americas, challenge our understanding of when Alzheimer’s disease processes begin.
The research team, led by Allison E. Aiello, found that by focusing primarily on older populations, researchers may have overlooked important early warning signs that appear decades before symptoms. This study is among the first to examine Alzheimer’s risk factors in young adults using a representative U.S. population sample.
For many Americans, this represents an opportunity disguised as a warning. While concerning, the research hints we might have a much longer window for prevention than previously believed – potentially transforming our approach to a disease that currently affects over 6 million Americans.
The Study: Following Young Adults Through Time
The research team examined data from the National Longitudinal Study of Adolescent to Adult Health, which has tracked thousands of participants since their teenage years in the mid-1990s. They assessed these individuals at ages 24-34 and again at 34-44, measuring various risk factors and testing their cognitive abilities.
The cornerstone of the assessment was each participant’s CAIDE score – a risk assessment tool that combines measurements including age, education, sex, blood pressure, body weight, cholesterol, and physical activity. Though developed to predict dementia risk in older adults, this study revealed it already showed connections to brain function in twenty-somethings.
Young adults with higher CAIDE scores performed worse on memory tests and cognitive challenges. Each single-point increase in CAIDE score was linked to measurable decreases in skills like holding and manipulating information in short-term memory.
These differences wouldn’t be noticeable in everyday life but mirror patterns seen in much older at-risk populations, pointing to cognitive processes that begin much earlier than previously recognized.
Beyond Heart Health: Inflammatory Markers and Brain Proteins
The team looked deeper than just cardiovascular health, examining specific proteins and inflammatory molecules in participants’ blood.
Total tau, a protein that accumulates in the brains of people with Alzheimer’s, was linked to worse immediate word recall in adults aged 34-44. Several inflammatory markers also showed connections to cognitive performance. Proteins involved in immune system communication were associated with poorer performance across multiple cognitive tests.
Interestingly, these associations grew stronger as participants moved from their late 20s into their late 30s, indicating a progressive relationship as people age.
Contrary to expectations, the APOE ε4 gene variant – the most well-known genetic risk factor for Alzheimer’s – showed no connection to cognitive function in these young adults. This outcome indicates that while genetics matter, lifestyle and cardiovascular health may exert stronger influences in early adulthood.
Reframing Alzheimer’s as a Lifelong Process
The researchers emphasize that their findings aren’t meant to cause alarm among younger adults about a disease they likely won’t face for decades Rather, it suggests that the biological pathways that eventually lead to Alzheimer’s may be active much earlier than we thought, giving us a potentially much longer window for prevention.
As Alzheimer’s cases are projected to nearly triple by 2050, these findings bring new urgency to early intervention. Current treatments mostly target older adults with existing symptoms, addressing brain damage that began decades earlier.
For younger adults, the research points to concrete actions that might protect long-term brain health: managing blood pressure, maintaining healthy weight, staying physically active, and continuing education. These factors appear to protect both heart and brain.
The biological mechanisms that eventually lead to Alzheimer’s may be quietly developing for 50 years before symptoms appear – making early adulthood interventions potentially our best chance at reducing the devastating impact of this disease.
Paper Summary
Methodology
Researchers analyzed data from the National Longitudinal Study of Adolescent to Adult Health (Add Health), a nationally representative cohort study that has followed participants since 1994-95. This cross-sectional analysis focused on two time points: Wave IV (2008) when participants were 24-34 years old, and Wave V (2016-2018) when they were 34-44 years old. The team measured the CAIDE score (a composite of age, education, sex, blood pressure, BMI, cholesterol, and physical activity), APOE ε4 status (a genetic risk factor), and blood biomarkers including total Tau, Neurofilament light (NfL), and various inflammatory markers (hsCRP, IL-1β, IL-6, IL-8, IL-10, TNF-α). Cognitive outcomes were assessed using immediate word recall, delayed word recall, and backward digit span tests. Sample sizes varied depending on the analysis, ranging from 4,507 to 11,449 participants in Wave IV and from 529 to 1,121 participants in Wave V.
Results
The study found that higher CAIDE scores were significantly associated with lower cognitive scores across all domains in Wave IV (ages 24-34). In Wave V (ages 34-44), similar trends were observed but weren’t statistically significant, possibly due to smaller sample size. APOE ε4 status showed no significant association with cognitive function at either time point. Total Tau was significantly associated with lower immediate word recall in Wave V. Several inflammatory markers showed significant associations: Wave IV hsCRP and IL-10 and Wave V IL-6, IL-1β, and IL-8 were linked to lower cognitive scores in various domains. The associations between inflammatory markers and cognition appeared to strengthen as participants aged from their late 20s to late 30s.
Limitations
The study had several limitations including significant differences in sample sizes between waves, with much smaller samples in Wave V that may have limited statistical power. Cross-sectional analyses precluded examination of trends over time, and ATN biomarkers were only available in Wave V. Different collection methods were used for immune markers between waves (dried blood spots in Wave IV versus serum/plasma in Wave V), which may explain some differences in results. While multiple associations were tested, the researchers did not correct for multiple comparisons, potentially increasing the risk of Type I errors.
Funding and Disclosures
The research was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (grant P01HD31921), the National Institute on Aging (cooperative agreements U01AG071448 and U01AG071450, grants R01AG057800 and P30AG066615), and other NIH funding (T32HD091058, P2CHD050924). The authors declared no conflicts of interest.
Publication Information
“Risk factors for Alzheimer’s disease and cognitive function before middle age in a U.S. representative population-based study” was published in The Lancet Regional Health – Americas (Volume 45, May 2025). Allison E. Aiello from Columbia University’s Butler Aging Center and Department of Epidemiology at Columbia University led the research team, with collaborators from Columbia University and the University of North Carolina at Chapel Hill.
I am a medical anthropologist researcher and author, and I study the impacts of lifestyle on the brain. This study is absurd. It is clearly selling Alzheimer’s disease treatments as early as possible, making this a marketing tool. “The researchers emphasize that their findings aren’t meant to cause alarm among younger adults about a disease they likely won’t face for decades Rather, it suggests that the biological pathways that eventually lead to Alzheimer’s may be active much earlier than we thought, giving us a potentially much longer window for prevention.” Really?! This is not meant to cause alarm! Of course it is, with the obvious promotion of improved lifestyle and cardiovascular health as a preventive care for Alzheimer’s. (Drugs will follow, of course.)
Any cognitive decline in this young cohort does not necessarily prove any relation to Alzheimer’s-related decline. There may be similarities is some measures of cognitive function, like word memory, but low scores do not mean Alzheimer’s is beginning. “Outcomes included immediate word recall, delayed word recall, and backward digit span.” There is more to cognition than these measures. And there are many reasons why people may decline in this ability apart from developing dementia. There is also normal reduction in cognitive processing that is not pathological.
To scare people about a disease that may or may not be in their future 50 years hence is not only absurd, it is unethical. It creates fear and negative expectations that can cause stress and poor cognitive outcomes, as people live up to negative medical expectations.