Individuals with a combination of vascular risk factors and higher levels of beta-amyloid protein in the brain may be on a speedier path of cognitive decline, suggests a study published May 21 in JAMA Neurology.
Lead author Jennifer S. Rabin, PhD, and colleagues evaluated 223 participants an average of 73.7 years old from the Harvard Aging Brain Study and found evidence of a synergistic effect for those two characteristics. Cardiovascular risk was determined from the Framingham Heart Study (FHS) risk score, while positron emission tomography (PET) scans informed the assessment of β-amyloid burden.
"Our findings suggest that having vascular risk factors like diabetes, smoking, and high blood pressure may accelerate the rate of cognitive decline in normal older adults, and that the effect of vascular risk on decline is magnified in people with higher brain amyloid levels," Rabin said in a press release. "Our findings support the rationale behind targeting modifiable vascular risk factors either alone or in combination with amyloid-lowering therapies to delay cognitive decline. Measures of vascular risk also may be able to complement existing biomarkers in identifying people at the greatest risk of cognitive decline."
In additional analyses, other vascular risk scores demonstrated similar results, showing an association with cognitive decline similar to that predicted by brain amyloid. However, individuals with both brain amyloid and high cardiovascular risk scores demonstrated the greatest odds of mental decline, which was evaluated during annual follow-up visits with memory, attention and language tests. Participants were followed for an average of 3.7 years.
All study patients were asymptomatic at baseline without uncontrolled diabetes or hypertension, so the authors acknowledged their cohort may be at a lower average risk of cardiovascular disease and cognitive impairment than the general population.
Research has shown that brain amyloid levels are associated with cognitive decline, although individual risk may vary. Some people who are amyloid-positive don’t show evidence of mental decline over longitudinal follow-up, necessitating the need for complementary risk-assessment tools, the authors noted.
“Vascular risk appears to be useful in identifying risk of cognitive decline above and beyond a full slate of MRI and PET measures of brain health,” senior study author Jasmeer P. Chhatwal, MD, PhD, said in the release. “Perhaps more importantly, we can reduce vascular risk factors through medical treatments and lifestyle interventions, and reducing these vascular risk factors might reduce memory loss over time—especially in people with high brain amyloid."