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• Posted April 25, 2025

Signs Of Dementia, Alzheimer's Can Appear Prior To Middle Age

Risk factors for dementia could start taking their toll as early as a person’s 20s and 30s, a new study says.

Younger adults who carry known risks for dementia performed worse on memory and thinking tests between ages 24 and 44, researchers report in the May issue of the journal The Lancet: Regional Health Americas.

The findings lay the groundwork for early detection of Alzheimer’s disease and dementia, researchers say.

This is the first study to look at risk factors of dementia and Alzheimer’s disease in a large group of generally healthy younger adults, researchers say.

“Previously, research on Alzheimer’s disease risk factors has focused on individuals aged 50 and older,” lead researcher Allison Aiello, a professor of epidemiology at the Columbia University Aging Center, said in a news release.

These new results show that well-established risk factors and blood biomarkers for dementia appear to start affecting cognitive function even before middle age, Aiello said.

These risk factors include education level, gender, blood pressure, cholesterol, exercise and body mass index, a measure of body fat based on height and weight, results show. All these are measured using a Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) score.

Researchers also learned that certain Alzheimer’s risk factors are present and related to brain function in people in their 40s or earlier, Aiello added.

These include levels of proteins like amyloid beta and tau that form plaques and tangles in the brains of people with Alzheimer’s, along with heart health and immune biomarkers.

“Additionally, we learned that certain Alzheimer’s risk factors — such as cardiovascular health, ATN (amyloid, tau, neurodegeneration), and immune biomarkers — are present and related to cognition in individuals in their forties and even earlier,” Aiello said.

For the study, researchers analyzed data from two waves of a long-term study tracking the health of teenagers as they grow into adults. The study started in 1994-1995, and researchers looked at participants again as they hit ages 24-34 and again at 34-44.

In their early 20s and 30s, participants completed brain function tests of their memory and thinking. Scores on those tests were compared to the participants’ CAIDE score as they approached middle-age.

Results showed that the higher a person scored on CAIDE, the worse they performed on tests of thinking skills at 34 to 44 years old.

“Exploring the relationship between the CAIDE score and cognitive function in young adulthood and early midlife in the U.S., showed that significant associations with cardiovascular risk factors can be observed well before age 50,” Aiello explained.

Researchers also looked at blood tests from the study participants, and found that a combined amyloid/tau score called ATN was linked to people’s brain function prior to middle age.

“Our overall findings suggest that blood-based biomarkers associated with Alzheimer’s disease are linked to differences in cognitive function decades before clinical symptoms and impairments even appear, highlighting the importance of early prevention strategies across the life course,” Aiello said.

“Identifying the early pathways to Alzheimer’s disease and cognitive impairment before older age is critical to slowing the expected rise of Alzheimer’s disease in the coming decades,” she added.

More information

The Alzheimer’s Association has more on early signs and symptoms of Alzheimer’s and dementia.

SOURCE: Columbia University, news release, April 22, 2025