A preliminary study to be presented at the American Stroke Association’s International Stroke Conference 2026 reveals that cerebral amyloid angiopathy (CAA), a condition where amyloid protein accumulates in brain blood vessels, is associated with a significantly increased risk of developing dementia within five years. Analyzing data from over 1.9 million Medicare beneficiaries aged 65 and older from 2016 to 2022, researchers found that individuals diagnosed with CAA were approximately four times more likely to develop dementia compared to those without CAA (42% vs. 10%). This elevated risk persisted even after accounting for stroke history.
“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 in New York City. The study examined the relationship between CAA, stroke, and dementia risk, tracking patients through health status changes over time. Among the key findings, individuals with CAA but no stroke were 4.3 times more likely to be diagnosed with dementia at any given time point compared to those with neither CAA nor stroke, while those with both CAA and stroke had a 4.5-fold increased risk. In contrast, stroke alone without CAA was associated with a 2.4-fold higher 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 noted. “This suggests that non-stroke-related mechanisms are instrumental to dementia risk in CAA.” The findings highlight the importance of proactive cognitive screening after a CAA diagnosis to address risk factors and potentially prevent further cognitive decline.
Steven M. Greenberg, M.D., Ph.D., FAHA, former chair of the International Stroke Conference and author of a commentary on Cerebral Amyloid Angiopathy | Stroke, emphasized the significance of small vessel diseases in dementia. “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,” said Greenberg, a professor of neurology at Harvard Medical School who was not involved in the study. He added that while dementia risk after any stroke is known, these results suggest an even greater risk for CAA patients.
The study has limitations, including reliance on administrative diagnosis codes from Medicare claims, which may not perfectly capture clinical diagnoses. Researchers used validated codes to minimize misclassification but lacked imaging data to confirm CAA and stroke diagnoses. Further prospective studies with standardized diagnostic approaches are needed to confirm these results. The findings are considered preliminary until published in a peer-reviewed journal. According to the American Heart Association’s 2026 Heart Disease and Stroke Statistics, stroke is now the #4 leading cause of death in the U.S., underscoring the urgency of understanding conditions like CAA that amplify dementia risk.
