Research Highlights:
Cerebral amyloid angiopathy, a condition caused by the buildup of amyloid (proteins) in brain blood vessels, was associated with increased risk of developing dementia within 5 years, in a study of nearly 2 million adults in the U.S. with health insurance coverage through Medicare.
There was a strong association between blood vessel protein buildup and increased dementia risk for all study participants with or without a history of stroke.
Researchers say these findings highlight the need to proactively screen for cognitive changes after a diagnosis of cerebral amyloid angiopathy to help prevent further cognitive decline.
Note: The study featured in this news release is a research abstract. Abstracts presented at the American Heart Association/American Stroke Association’s scientific meetings are not peer-reviewed, and the findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.
Embargoed until 4 a.m. CT/5 a.m. ET, Thursday, Jan. 29, 2026
DALLAS, Jan. 29, 2026 — Cerebral amyloid angiopathy (CAA) is a condition where protein (called amyloid) builds up in the brain, making blood vessels weak. People with CAA are four times more likely to develop dementia within five years, regardless of whether they have had a stroke, according to a preliminary study to be presented at the American Stroke Association’s International Stroke Conference 2026. The meeting is in New Orleans, Feb. 4-6, 2026, and is a world premier global event dedicated to advancing stroke and brain health science.
Cerebral amyloid angiopathy (CAA) can lead to hemorrhagic stroke (bleeding stroke) and raises the risk of ischemic stroke (clot-caused stroke). As people age, some amyloid protein can collect in the brain’s blood vessels without causing symptoms. People receive a clinical diagnosis of CAA when the buildup becomes significant enough to damage the vessels and affect brain function. In some severe cases, the protein deposits can cause the walls of blood vessels to crack. This can lead to blood leaking out and damaging the brain, and this damage is known as a bleeding or hemorrhagic stroke. CAA also contributes to cognitive impairment and is often found in people with Alzheimer’s Disease. This study investigated the risk of developing dementia among adults diagnosed with CAA, the link between CAA and stroke and the risk of dementia.
“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.
“Our study calculated estimates from a large sample of Medicare patients whether people with CAA are more likely to be newly diagnosed with dementia and to clarify how CAA and stroke — separately and together — relate to new dementia diagnoses.”
Researchers analyzed the health information for more than 1.9 million adults covered by Medicare, ages 65 and older, from 2016 to 2022. They reviewed newly diagnosed dementia cases and how ischemic and hemorrhagic stroke are related to dementia risk in people with CAA. Patients were tracked through health changes — no CAA or stroke, CAA only, stroke only, both CAA and stroke — over time. By observing health status over time, the researchers could see how much time each patient spent in each state and pinpoint the onset of dementia, Bruce explained.
They found that CAA greatly increased the risk of developing dementia within the 5-year estimate, even more than the effects of stroke.
The analysis found:
The risk of being diagnosed with dementia within five years of CAA diagnosis was about four times higher in people with CAA versus people without CAA (42% vs. 10%, respectively).
People with CAA and stroke were 4.5 times more likely to be diagnosed with dementia at any given time point, compared to adults with neither CAA nor stroke.
People with CAA without stroke were 4.3 times more likely to be diagnosed with dementia at any given time point, compared to patients with neither CAA nor stroke.
Adults with only stroke without CAA were 2.4 times more likely to be diagnosed with dementia at any given time point, compared to patients with neither CAA nor stroke.
“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. This suggests that non-stroke-related mechanisms are instrumental to dementia risk in CAA,” Bruce said. “These results highlight the need to proactively screen for cognitive changes after a diagnosis of CAA and address risk factors to prevent further cognitive decline.”
According to Steven M. Greenberg, M.D., Ph.D., FAHA, former chair of the International Stroke Conference and author of the commentary, Cerebral Amyloid Angiopathy | Stroke, “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. We know there is risk for dementia after any type of stroke, but these results suggest even greater risk for CAA patients.” Greenberg is also a professor of neurology at Harvard Medical School in Boston and was not involved in this study.
Study limitations included that researchers obtained clinical study information from administrative diagnosis codes used in inpatient and outpatient health insurance claims submitted to Medicare. “These codes are an imperfect proxy for clinical diagnoses, and misclassifications can occur,” Bruce said. Researchers tried to mitigate the limitation by using codes that have been shown to accurately capture correct diagnoses in administrative data. They also did not have access to imaging data to more rigorously assess the diagnoses of CAA and stroke.
Further research is needed to confirm these results, especially with prospective studies that follow patients forward (instead of looking back in time). Those studies should include standardized approaches for diagnosing CAA and stroke.
Study details, background and design:
This retrospective study, which examined past data, included information from both inpatient and outpatient health claims for 1,909,365 adults in the U.S. covered by Medicare. Of those, 752 (0.04%) received a CAA diagnosis during the study period.
Participants were age 65 and older, with an average age of 73 years; 54% were women and 46% were men. The participants were 82.4% white adults, 7.3% Black adults, and 10.3% were individuals from other racial groups.
The study used data collected by Medicare on health insurance claims submitted by professionals and hospitals in the course of clinical care. Researchers had access to multiple years of data, from 2016 to 2022.
Co-authors, funding and disclosures are listed in the abstract.
Statements and conclusions of studies that are presented at the American Heart Association/American Stroke Association’s scientific meetings are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. Abstracts presented at the Association’s scientific meetings are not peer-reviewed, rather, they are curated by independent review panels and are considered based on the potential to add to the diversity of scientific issues and views discussed at the meeting. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.
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Additional Resources:
Video interview clips with American Stroke Association volunteer expert, Steven M. Greenberg, M.D., Ph.D., FAHA, and other multimedia assets are available on the right column of the release link.
Link to abstract in the American Stroke Association International Stroke Conference 2026 Online Program Planner
New 1/21/2026 - 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. Learn more at www.stroke.org or www.DerrameCerebral.org.
American Heart Association/American Stroke Association: Stroke Hub or in Español. Link to additional health topic Fact Sheets.
American Stroke Association health information: Uncommon Causes of Stroke
American Stroke Association news release: Risk of dementia was nearly three times higher the first year after a stroke (Feb. 2024)
American Heart Association news release: Cognitive impairment after stroke is common, and early diagnosis and treatment needed (May 2023)
For more news at American Stroke Association International Stroke Conference 2026, follow us on X @HeartNews #ISC26
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About the American Stroke Association
The American Stroke Association is a relentless force for a world with fewer strokes and longer, healthier lives. We team with millions of volunteers and donors to ensure equitable health and stroke care in all communities. We work to prevent, treat and beat stroke by funding innovative research, fighting for the public’s health, and providing lifesaving resources. The Dallas-based association was created in 1998 as a division of the American Heart Association. To learn more or to get involved, call 1-888-4STROKE or visit stroke.org. Follow us on Facebook and X.
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