A new study shows the need to research the risk factors of Alzheimer’s disease in healthy young people.

By Yasemin Isbilir

Alzheimer’s disease is usually seen as something that happens later in life. But a new study shows that some of the risks tied to the disease can already be seen in people in their 20s and 30s. This is a surprising discovery for a condition that has no cure and remains a widely feared disease of aging.

The research, published in May 2025, in The Lancet Regional Health – Americas, found that memory scores were linked to well-known Alzheimer’s risk factors and blood markers decades before most people notice problems.

“This study supports what Alzheimer’s and aging researchers would say in general to people in their 20s and 30s,” says Jennifer Momkus, Ph.D., a co-author of the study and a postdoctoral researcher and epidemiologist. “Even in this younger age when we believe people are in the healthiest years of their life, some of the aging processes are already starting.”

In the paper, a group of researchers at Columbia University Mailman School of Public Health and the University of North Carolina’s Carolina Population Center used data from over 10,000 adults ages 24 to 44 from the Add Health study, a national longitudinal study which has tracked Americans since they were teens in the 1990s. The participants completed different memory tasks such as recalling lists of words and repeating numbers backward and also, gave blood samples.

The team then looked at Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) scores, which is an algorithm that combines age, education, blood pressure, cholesterol, body mass, and exercise. They also looked at proteins in the brain such as tau and neurofilament light chain (NfL), which can signal damage. Additionally, they studied inflammation markers like CRP and IL-6, which show how the body responds to stress.

The results showed an association between higher CAIDE scores, levels of tau and inflammatory markers with lower memory scores. “This is a first step in research,” Momkus said. “We are looking at relationships between biomarkers and cognitive function at the same time, so we cannot say any of this is causal. But this gives us a reason to continue this research at this age group.”

Alzheimer’s affects more than 6 million Americans and has no cure. The financial cost is also massive. The economic burden of Alzheimer’s and related dementias is projected to reach $781 billion this year in the United States alone. While research focuses on older adults, this study highlights the importance of looking earlier in life. Momkus explains that current research is heavily dominated by older populations, but for conditions without proven treatments, prevention is a main way we can address it.

That message of prevention is where Aaron Reuben, Ph.D, an assistant professor of neuropsychology and environmental health at the University of Virginia, sees room for growth. Reuben studies how the environment shapes brain health and has conducted research on improving Alzheimer’s risk indexes, including CAIDE.

“The idea of a checklist risk score comes to us from the world of cardiovascular disease prevention,” Reuben said. “CAIDE was the first Alzheimer’s focused checklist, but it only used a few of the known or proposed risk factors for the disease and weighted heavily the ones that general practitioners already track. It works, but it leaves out decades of evidence that says there are many other risk factors too.” Reuben explained that the current approach focuses on information doctors can easily collect, such as blood pressure or body mass. He believes the next step is to create more comprehensive and personalized risk assessments that reflect how dementia multiplies and develops differently for different people.

Another challenge lies in research design. Because Alzheimer’s shows up late in life but unfolds over decades, there is a need for forward facing studies on people that follow participants for years. Aging researchers often use animals such as mice for Alzheimer’s as mice have a shorter lifespan as compared to humans and develop disease at faster rates. Researchers could use mice to look at midlife but also use more forward facing studies of people. This kind of research takes time, money and patience, but is crucial for understanding how early intervention should begin.

Understanding when Alzheimer’s risk begins is also central to the work of Zhihai Huang, a Ph.D. student in the Department of Pharmacology, Toxicology, and Neuroscience at Louisiana State University Health Shreveport. His research focuses on how early life adversity affects brain development and long-term risk of Alzheimer’s disease in mice. “Prolonged cortisol exposure can disrupt the blood-brain barrier and trigger the accumulation of amyloid beta and tau,” Huang said. Amyloid beta (A-beta) and tau are proteins in the brain that form clumps and damage cells in Alzheimer’s and related dementias. He explained that this chronic inflammation may be another factor to consider in explaining how risk factors can begin early in life and can raise the risk of Alzheimer’s later on.

This information can feel overwhelming when people think of Alzheimer’s as an inevitable part of aging. Although age is the most well-known risk factor, research shows that it is not a “normal” outcome of getting older and Alzheimer’s is still a disease state. Misconception about the disease can delay diagnosis and prevent people from seeking treatment or making preventive changes early on.

Public awareness campaigns have found that encouraging early intervention, cognitive screening, and overall healthy behaviors can make a difference in populations. Aging research also supports healthy eating patterns such as the Mediterranean diet, protecting hearing and vision, and reducing inflammation as important steps toward prevention. Reuben emphasized that these habits coincide with those that protect the heart such as regular exercise and abstinence from alcohol and cigarettes. He added that keeping the brain active, whether it be through higher education or mentally challenging oneself, can help reduce long-term risk.

The Lancet study was the first of its kind in Alzheimer’s research to systematically review such a young population. The research doesn’t prove these early risks lead to Alzheimer’s. It does show a possible window of opportunity for prevention and raises questions for future studies. As studies like this continue, researchers hope to look into when and how Alzheimer’s risk truly begins. Further research should focus on refining risk scores, studies of humans, and testing lifestyle changes earlier in life to investigate what gives people the best chance to protect their brains.