A new preliminary study reveals that cerebral amyloid angiopathy (CAA), a condition characterized by the buildup of amyloid proteins in brain blood vessels, is associated with a fourfold increase in the risk of developing dementia within five years. The findings, based on an analysis of nearly 2 million Medicare beneficiaries, highlight the importance of proactive cognitive screening after a CAA diagnosis. The research is set to be presented at the American Stroke Association’s International Stroke Conference 2026 in New Orleans, Feb. 4-6.
CAA weakens blood vessels in the brain, leading to an increased risk of hemorrhagic and ischemic stroke. However, this study, led by Dr. Samuel S. Bruce of Weill Cornell Medicine, found that the dementia risk associated with CAA is substantial even in the absence of stroke. Among the study participants, 42% of those with CAA developed dementia within five years, compared to 10% of those without CAA. The risk remained similarly elevated for individuals with CAA regardless of whether they had a stroke, suggesting that non-stroke mechanisms play a crucial role in cognitive decline.
The study analyzed health records from 2016 to 2022 for adults aged 65 and older covered by Medicare. Of the 1,909,365 participants, 752 were diagnosed with CAA. The researchers tracked transitions between health states—no CAA or stroke, CAA only, stroke only, or both—to estimate dementia risk. They found that people with CAA and no stroke were 4.3 times more likely to be diagnosed with dementia at any given time compared to those with neither condition, while those with CAA and stroke faced a 4.5 times higher risk. In contrast, stroke alone was associated with a 2.4-fold increased risk.
“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,” said Bruce. Dr. Steven M. Greenberg, a neurologist at Harvard Medical School not involved in the study, added, “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 has limitations, including the use of administrative diagnosis codes that may not perfectly capture clinical diagnoses. The researchers did not have access to imaging data to confirm CAA or stroke diagnoses. Further prospective studies are needed to validate these findings. The abstract is considered preliminary until published in a peer-reviewed journal. For more information on stroke and brain health, visit stroke.org or the American Heart Association’s news release on post-stroke dementia risk.
