The demographic and medical correlates of plasma aβ40 and aβ42.
Plasma amyloid β-42 (Aβ42) and Aβ42/Aβ40 are increasingly recognized as biomarkers for dementia, with low levels indicating increased risk. Little is known about the demographic and medical correlates of plasma Aβ40 or Aβ42. In 997 community-dwelling, nondemented older adults from the Health, Aging, and Body Composition Study, we determined the cross-sectional association between a wide range of demographic and medical variables with Aβ40 and Aβ42. In multivariate stepwise linear regression models, Aβ40 was significantly associated with race (β=-14.70, F=22.01, P<0.0001), age (β=1.34, F=6.39, P=0.01), creatinine (β=52.91, F=151.77, P<0.0001), and the serum brain-derived neurotrophic factor (β=-0.0004, F=7.34, P=0.007); Aβ42 was significantly associated with race (β=-3.72, F=30.83, P<0.0001), sex (β=1.39, F=4.32, P=0.04), education (β=1.50, F=4.78, P=0.03), apolipoprotein E e4 genotype (β=-2.82, F=16.57, P<0.0001), and creatinine (β=9.32, F=120.09, P<0.0001). These correlates should be considered as potential confounders in future studies investigating plasma Aβ as a biomarker of dementia. Understanding fully how these correlates mediate or modify the association between plasma Aβ and dementia will be a fundamental step in determining the biological pathways through which plasma Aβ40 and Aβ42 are associated with dementia, and in determining their full potential as biomarkers.
Department of Epidemiology, Center for Aging and Population Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15213, USA. alw111@pitt.edu
Andrea L
AL
Metti
Jane A
JA
Cauley
Hilsa N
HN
Ayonayon
Tamara B
TB
Harris
Caterina
C
Rosano
Jeff D
JD
Williamson
Kristine
K
Yaffe
D000368:Aged; D016229:Amyloid beta-Peptides / Q000097:blood*; D015415:Biomarkers / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D010446:Peptide Fragments / Q000097:blood*; D012016:Reference Values
D016229:Amyloid beta-Peptides; D015415:Biomarkers; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40)