Signs of Dementia Risk May Surface as Early as Your 20s, Study Finds

Early warnings of dementia may begin much sooner than anyone imagined — even in a person’s 20s and 30s — according to a striking new study published in The Lancet: Regional Health – Americas.

Researchers tracking young adults over two decades discovered that individuals carrying known dementia risk factors performed worse on memory and cognitive tests as early as age 24. The study, led by Dr. Allison Aiello of Columbia University’s Aging Center, marks the first large-scale effort to examine dementia indicators in younger, generally healthy adults.

“Historically, our understanding of Alzheimer’s disease has focused on individuals aged 50 and up,” Aiello said in a statement. “But our findings reveal that the physiological roots of dementia can start to affect brain function long before middle age.”

The research team analyzed participants from a long-term health study that began in the mid-1990s, assessing their cognitive function at ages 24–34 and again at 34–44. They found a strong connection between lower performance on thinking and memory tests and higher scores on the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) scale — a tool that factors in education, blood pressure, cholesterol, exercise habits, and body mass index.

But the surprises didn’t stop there. Blood analyses revealed that some biological hallmarks of Alzheimer’s — like amyloid plaques, tau tangles, and markers of neurodegeneration — were already present and influencing cognitive function in participants decades before symptoms typically surface.

“Seeing these connections this early is remarkable,” Aiello noted. “It highlights the silent buildup of Alzheimer’s pathology long before clinical signs emerge and suggests that cardiovascular health and inflammation may be intertwined with cognitive decline far earlier than we realized.”

The implications are profound. If brain changes linked to Alzheimer’s are taking root in the 20s and 30s, there may be a critical window for early lifestyle interventions — a chance to alter the course of cognitive aging before it’s too late.

“Our results underline the need to rethink when — and how — we start dementia prevention efforts,” Aiello emphasized. “By identifying and addressing risk factors across the lifespan, we have a better shot at curbing the growing tide of Alzheimer’s disease in the decades ahead.”

The study provides a rallying cry for a more proactive approach to brain health, suggesting that memory preservation may well begin in youth — not retirement.