A preliminary study analyzing health data from nearly 2 million U.S. adults covered by Medicare has identified a strong association between cerebral amyloid angiopathy (CAA) and increased risk of developing dementia within five years. The research, to be presented at the American Stroke Association’s International Stroke Conference 2026, found that individuals with CAA were approximately four times more likely to receive a dementia diagnosis compared to those without the condition, regardless of stroke history.
Cerebral amyloid angiopathy is characterized by the accumulation of amyloid proteins in the brain's blood vessels, which weakens them and can lead to both hemorrhagic stroke (bleeding stroke) and ischemic stroke (clot-caused stroke). The condition often coexists with Alzheimer's disease and contributes to cognitive impairment. According to the study, the risk of being diagnosed with dementia within five years of a CAA diagnosis was 42% for people with CAA versus 10% for those without it.
The research analyzed health information from 1,909,365 adults aged 65 and older from 2016 to 2022, tracking patients through various health states: no CAA or stroke, CAA only, stroke only, and both CAA and stroke. The findings revealed that 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 condition. Notably, those with CAA without stroke were 4.3 times more likely, while adults with only stroke without CAA were 2.4 times more likely.
"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," said study author Samuel S. Bruce, M.D., M.A., an assistant professor of neurology at Weill Cornell Medicine. "This suggests that non-stroke-related mechanisms are instrumental to dementia risk in CAA."
The implications of these findings are significant for clinical practice and public health. Researchers emphasize the need for proactive screening for cognitive changes following a CAA diagnosis to help 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 the subject, noted that "diseases of the brain’s small blood vessels are major contributors to dementia" and that CAA often occurs with Alzheimer's disease, creating a "potent 1-2 punch." More information about cerebral amyloid angiopathy can be found in the journal Stroke.
Study limitations include reliance on administrative diagnosis codes from Medicare claims, which may not perfectly capture clinical diagnoses, and lack of access to imaging data for more rigorous assessment. The researchers attempted to mitigate these limitations by using codes shown to accurately capture diagnoses in administrative data. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal, as abstracts presented at American Heart Association/American Stroke Association scientific meetings are not peer-reviewed.
The study's retrospective design examined past data from both inpatient and outpatient health claims. Of the nearly 1.9 million participants, 752 (0.04%) received a CAA diagnosis during the study period. The participant pool was 54% women and 46% men, with an average age of 73 years, and comprised 82.4% white adults, 7.3% Black adults, and 10.3% individuals from other racial groups. Additional resources, including the abstract, are available through the American Stroke Association International Stroke Conference 2026 Online Program Planner.
These results underscore the importance of recognizing CAA as a significant risk factor for dementia, independent of stroke. With stroke now ranked as the fourth leading cause of death in the U.S. according to the American Heart Association’s 2026 Heart Disease and Stroke Statistics, understanding the connections between cerebrovascular conditions and cognitive decline becomes increasingly critical for developing effective prevention and intervention strategies.
