A preliminary study analyzing health data from nearly 2 million U.S. adults covered by Medicare has found that cerebral amyloid angiopathy significantly increases the risk of developing dementia within five years. The research, to be presented at the American Stroke Association’s International Stroke Conference 2026, indicates that individuals with CAA are approximately four times more likely to receive a dementia diagnosis compared to those without the condition.
Cerebral amyloid angiopathy is characterized by the accumulation of amyloid protein in the walls of the brain's blood vessels, which can weaken them and lead to complications such as hemorrhagic stroke and ischemic stroke. According to the study's findings, 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 analysis revealed that the presence of CAA alone substantially elevates dementia risk, independent of stroke history. People with CAA but no stroke were 4.3 times more likely to be diagnosed with dementia at any given time compared to individuals with neither condition.
Similarly, those with both CAA and stroke faced a 4.5 times higher risk. In contrast, adults with only stroke without CAA had a 2.4 times 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," 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." Researchers examined health information for 1,909,365 adults aged 65 and older from 2016 to 2022, tracking newly diagnosed dementia cases and the relationship between ischemic and hemorrhagic stroke and dementia risk in people with CAA.
Of the participants, 752 received a CAA diagnosis during the study period. The team used data from Medicare health insurance claims, though they acknowledged limitations, including the potential for misclassification with administrative diagnosis codes and the lack of imaging data to rigorously assess CAA and stroke diagnoses. Further details are available in the abstract in the American Stroke Association International Stroke Conference 2026 Online Program Planner.
The implications of these findings are significant for clinical practice. "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," Bruce emphasized. Steven M. Greenberg, M.D., Ph.D., FAHA, a professor of neurology at Harvard Medical School and author of a related commentary, noted in Cerebral Amyloid Angiopathy | Stroke that "diseases of the brain’s small blood vessels are major contributors to dementia," with CAA and Alzheimer's disease often combining for a potent effect. The study underscores that while stroke is a known risk factor for dementia, CAA presents an even greater risk, necessitating increased vigilance in patient management and further research to confirm these preliminary results through prospective studies.
