A new study presented at the American Stroke Association’s International Stroke Conference 2026 reveals that cerebral amyloid angiopathy (CAA)—a condition characterized by amyloid protein buildup in brain blood vessels—significantly raises the risk of dementia within five years, independent of stroke history. The research, which analyzed health data from over 1.9 million Medicare beneficiaries aged 65 and older, found that individuals with CAA were approximately four times more likely to develop dementia compared to those without the condition.
“Many people with CAA develop dementia; however, so far, clinicians haven’t had clear, large-scale estimates on how often and how quickly dementia progresses in these patients,” said study author Samuel S. Bruce, M.D., M.A., an assistant professor of neurology at Weill Cornell Medicine. The study tracked patients from 2016 to 2022, categorizing them by CAA and stroke status. Among the 752 patients diagnosed with CAA, the five-year dementia risk was 42%, compared to 10% for those without CAA. The risk remained elevated even in CAA patients without a history of stroke, who were 4.3 times more likely to receive a dementia diagnosis at any given time point, while those with stroke alone had a 2.4-fold increased risk.
“What stood out was that the risk of developing dementia among those with CAA without stroke was similar to those with CAA with stroke, and both conditions had a higher increase in the incidence of dementia when compared to participants with stroke alone,” Bruce explained. “This suggests that non-stroke-related mechanisms are instrumental to dementia risk in CAA.” The findings underscore the importance of proactive cognitive screening after a CAA diagnosis to identify early signs of decline and address modifiable risk factors.
CAA is known to cause hemorrhagic stroke and is often found in individuals with Alzheimer’s disease. According to Steven M. Greenberg, M.D., Ph.D., FAHA, a professor of neurology at Harvard Medical School who was not involved in the study, “Diseases of the brain’s small blood vessels are major contributors to dementia. This is especially true for CAA, which often occurs together with Alzheimer’s disease, making for a potent 1-2 punch.” The study, though preliminary and not yet peer-reviewed, provides large-scale estimates that could guide clinical practice.
The research relied on administrative diagnosis codes from Medicare claims, which may introduce misclassification. Bruce noted that the team used validated codes to mitigate this limitation but lacked imaging data to confirm diagnoses. Future prospective studies with standardized diagnostic approaches are needed to validate these results. The study was presented at the American Stroke Association’s International Stroke Conference 2026 and is considered preliminary until published in a peer-reviewed journal.
