Plasma ß-amyloid and cognitive decline.
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.
Cosentino
Stephanie A
SA
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.
Stern
Yaakov
Y
Sokolov
Elisaveta
E
Scarmeas
Nikolaos
N
Manly
Jennifer J
JJ
Tang
Ming Xin
MX
Schupf
Nicole
N
Mayeux
Richard P
RP
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
D016229:Amyloid beta-Peptides; D001057:Apolipoproteins E; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42)