title: Plasma ß-amyloid and cognitive decline.
abstract: OBJECTIVE
  To determine if plasma β-amyloid (Aβ) levels (1) can be linked to specific cognitive changes that constitute conversion to Alzheimer disease (AD) and (2) correspond to cognitive change independent of dementia.
  
  
  METHODS
  Longitudinal study including 3 visits during approximately 4¹/₂ years (2000-2006).
  
  
  METHODS
  Northern Manhattan community.
  
  
  METHODS
  Eight hundred eighty individuals from a population-based and ethnically diverse sample who had 2 plasma Aβ measurements and were dementia free at the time of the first Aβ sample; 481 remained cognitively healthy, 329 were cognitively or functionally impaired but not demented at any point, and 70 developed AD.
  
  
  METHODS
  General estimating equations tested the association between plasma Aβ (baseline and change in values) and cognitive change (composite score and memory, language, and visuospatial indices).
  
  
  RESULTS
  High baseline plasma Aβ42 (P = .01) and Aβ40 (P = .01) and decreasing/relatively stable Aβ42 (P = .01) values were associated with faster decline in multiple cognitive domains. In those who remained cognitively healthy, high baseline plasma Aβ42 (P = .01) and decreasing/relatively stable plasma Aβ42 (P = .01) was associated with faster cognitive decline, primarily in memory.
  
  
  CONCLUSIONS
  The association between plasma Aβ and multiple aspects of cognition more clearly specifies the previously documented downward trajectory of plasma Aβ with AD onset. The predominant association with memory seen only in healthy elderly individuals also suggests that plasma Aβ is linked with even earlier neurologic changes that may or may not culminate in dementia.
authors.affiliation: The Gertrude H. Sergievsky Center, Taub Institute for Research in Alzheimer’s Disease and the Aging Brain, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Cosentino
authors.forename: Yaakov
authors.initials: Y
authors.lastname: Stern
authors.forename: Elisaveta
authors.initials: E
authors.lastname: Sokolov
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Scarmeas
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Manly
authors.forename: Ming Xin
authors.initials: MX
authors.lastname: Tang
authors.forename: Nicole
authors.initials: N
authors.lastname: Schupf
authors.forename: Richard P
authors.initials: RP
authors.lastname: Mayeux
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016229:Amyloid beta-Peptides / Q000097:blood*; D001057:Apolipoproteins E / Q000235:genetics; D003072:Cognition Disorders / Q000097:blood*; D018672:Community Health Planning; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005838:Genotype; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010446:Peptide Fragments / Q000097:blood
chemical_list: D016229:Amyloid beta-Peptides; D001057:Apolipoproteins E; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42)