Plasma Amyloid, Inflammatory Markers, and Risk of Dementia in the Ginkgo Evaluation of Memory Study

Most individuals with dementia have mixed neurodegenerative and vascular pathologies that may interact to accelerate cognitive decline. Prior studies have shown that two vascular inflammatory markers (pentraxin 3 and serum amyloid P) and plasma amyloid are associated with dementia, though results have been inconsistent. Using weighted Cox proportional hazards regression, we evaluated the joint associations of these inflammatory markers and plasma amyloid (Aβ1-42 and Aβ1-42/Aβ1-40 ratio) with risk of all-cause dementia. All four biomarkers were significantly associated with risk of dementia, and a composite of biomarker z-scores showed substantially higher risk for those with high levels of both inflammation and amyloid. Results for inflammatory markers and the composite z-score were stronger for individuals with MCI at baseline. Assessing inflammatory biomarkers in combination with plasma amyloid may lead to better prediction of symptomatic dementia onset than plasma amyloid alone.