Cerebral Amyloid Angiopathy’s Impact on Dementia Risk

A little-known condition called cerebral amyloid angiopathy (CAA) could significantly increase the risk of dementia among older adults, as suggested by a preliminary study from the American Heart Association.

CAA involves the accumulation of proteins in the brain that weaken blood vessels. According to the association, these protein buildups might happen occasionally without noticeable symptoms, especially as we age.

When this buildup affects brain function, doctors typically diagnose it through imaging techniques such as MRI or PET scans. In its severe stages, CAA can lead to strokes.

The Cleveland Clinic notes that roughly 23-29% of individuals over 50 have moderate to severe CAA.

In a recent study, nearly two million adults aged 65 and older were examined for health data related to CAA. They tracked new dementia diagnoses from 2016 to 2022, categorizing participants based on whether they had CAA, experienced strokes, or both.

The findings showed that about 42% of patients with CAA were diagnosed with dementia within five years, compared to only 10% among those without CAA—a difference nearing four times. Interestingly, this risk remained substantial even for those without a history of strokes.

“What stood out was that those with CAA but no stroke had a similar risk of developing dementia as those who had both conditions,” said Samuel S. Bruce, an assistant professor of neurology at Weill Cornell Medical College in New York City. “This suggests that the protein buildup may severely impact brain function.”

He further emphasized the importance of monitoring cognitive function closely once CAA is diagnosed, and addressing any risk factors promptly to mitigate further cognitive decline.

The findings were initially shared at the American Stroke Association’s International Stroke Conference in New Orleans and may undergo additional peer evaluation before final publication.

Despite the solid associations uncovered in the study, some limitations were noted. The exact mechanisms through which these protein deposits affect brain function, beyond causing strokes, remain unclear. Furthermore, the study relied on administrative diagnosis codes from Medicare claims, which Bruce described as “imperfect” alternatives to formal clinical diagnoses.

To enhance accuracy, researchers utilized codes that previous investigations deemed reliable, but they lacked access to brain imaging tests that could definitively confirm the presence of CAA or strokes.

Healthcare professionals might recommend testing for CAA in older individuals who present new cognitive symptoms possibly related to small vessel disease, or if they have experienced a brain bleed or stroke.