A massive analysis of Medicare health records suggests a little-known brain blood vessel disorder may dramatically increase the risk of dementia.
A large U.S. Medicare study of nearly 2 million adults aged 65+ found that cerebral amyloid angiopathy (CAA) is strongly linked to a much higher risk of developing dementia within five years. People with CAA were about four times more likely to be diagnosed with dementia than those without CAA, even if they had never had a stroke.
Key findings show that dementia risk in people with CAA alone was almost as high as in those with both CAA and stroke, and higher than in people who had a stroke without CAA. About 42% of individuals with CAA developed dementia within five years, compared with about 10% of those without CAA.
These results suggest that CAA itself—beyond its role in causing strokes—plays a major role in cognitive decline, likely through damage to small brain blood vessels. Researchers and experts emphasize the need for early and routine cognitive screening after a CAA diagnosis to help detect and potentially slow further decline. The study was retrospective and based on insurance claims, so further prospective research with detailed clinical and imaging data is needed.