A preliminary study presented at the American Stroke Association's International Stroke Conference 2026 reveals that cerebral amyloid angiopathy (CAA), a condition characterized by amyloid protein buildup in brain blood vessels, is linked to a significantly increased risk of dementia within five years. Analyzing data from nearly 2 million Medicare beneficiaries aged 65 and older, researchers found that individuals diagnosed with CAA were approximately four times more likely to develop dementia compared to those without the condition.
The study, led by Dr. Samuel S. Bruce of Weill Cornell Medicine, examined health claims from 2016 to 2022. Among 1,909,365 adults, 752 (0.04%) had a CAA diagnosis. The analysis showed that 42% of those with CAA were diagnosed with dementia within five years, versus 10% of those without CAA. Notably, the elevated risk persisted even when patients had no history of stroke. Those with CAA alone were 4.3 times more likely to develop dementia, while those with both CAA and stroke faced a 4.5 times higher risk. In contrast, stroke alone increased dementia risk by 2.4 times.
“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 said. “This suggests that non-stroke-related mechanisms are instrumental to dementia risk in CAA.”
CAA is known to cause hemorrhagic and ischemic strokes, but this study underscores its direct impact on cognitive decline. Dr. Steven M. Greenberg of Harvard Medical School, who was not involved in the study, noted, “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.”
The findings carry significant implications for clinical practice. Bruce emphasized the need for proactive cognitive screening after a CAA diagnosis. “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,” he said.
Limitations include reliance on administrative codes, which may misclassify diagnoses, and lack of imaging data. The researchers call for prospective studies with standardized diagnostic criteria to confirm these results. The abstract is considered preliminary until published in a peer-reviewed journal.
The American Stroke Association, which organized the conference, provides resources on stroke and brain health at stroke.org and DerrameCerebral.org.
