Researchers at the Mayo Clinic have developed a risk calculator that can estimate a person’s likelihood of developing mild cognitive impairment or dementia up to a decade before symptoms appear, according to a new analysis published in The Lancet Neurology.
The tool uses four key markers: age, sex, the APOE ε4 genetic variant, and brain amyloid levels measured by PET scans. It is based on data from the Mayo Clinic Study of Aging, a community project that has followed thousands of adults for nearly 20 years. The analysis included nearly 5,900 cognitively healthy adults and tracked their outcomes using medical records, even after they left the study.
Researchers found that dementia occurred twice as often among people who dropped out of the study compared with those who stayed. That level of follow-up gave the team unusually accurate data on real-world Alzheimer’s risk.
Brain amyloid emerged as the strongest predictor
Amyloid proteins accumulate silently in the brain for years before cognitive changes appear. People with higher amyloid levels had significantly greater 10-year and lifetime risk of cognitive decline, regardless of age, sex, or genetic background. Among 75-year-olds who carry the APOE ε4 gene, lifetime risk of mild cognitive impairment jumped from 56 percent among those with low amyloid to more than 80 percent among those with high amyloid.
Women carried a higher lifetime risk than men, a finding that matches long-standing epidemiological patterns. The reasons include hormonal changes, immune differences, and longer life expectancy. The APOE ε4 gene also raised risk across all ages and amyloid levels, with high amyloid further amplifying that genetic vulnerability.
Implications for early detection and prevention
Researchers said the risk calculator points to a future where brain health is assessed individually, similar to how cholesterol scores and coronary calcium scans guide heart disease prevention. While the tool is still a research instrument, it could eventually help doctors decide when to recommend amyloid-lowering therapies or lifestyle interventions.
The study also reinforced the role of daily habits in shaping long-term brain health. Maintaining cardiorespiratory fitness, supporting metabolic health, prioritizing quality sleep, eating a nutrient-rich diet, staying socially connected, and continuing to learn new things have all been linked to slower cognitive decline.
The analysis drew from the Mayo Clinic Study of Aging, a community-based project that has followed thousands of adults for nearly two decades. The researchers noted that early detection tools like this one could change how Alzheimer’s disease is managed, moving from a reactive model to one where risk is identified long before memory loss begins.
