Plasma A[beta]40 and A[beta]42 and Alzheimer's disease: relation to age, mortality, and risk

Neurology. 2003 Nov 11;61(9):1185-90. doi: 10.1212/01.wnl.0000091890.32140.8f.


Background: Plasma amyloid [beta]-peptide (A[beta]) 40 and A[beta]42 levels are increased in persons with mutations causing early-onset familial Alzheimer's disease (AD). Plasma A[beta]42 levels were also used to link microsatellite genetic markers to a putative AD genetic locus on chromosome 10 and were observed in patients with incipient sporadic AD.

Methods: The authors measured plasma A[beta]40 and A[beta]42 levels using a sandwich ELISA after the initial examination of 530 individuals participating in an epidemiologic study of aging and dementia. Participants were examined at 18-month intervals, and plasma A[beta]40 and A[beta]42 levels were repeated in 307 subjects 3 years after baseline.

Results: Compared with individuals who never developed AD, patients with AD at baseline and those who developed AD during the follow-up had significantly higher A[beta]42, but not A[beta]40, plasma levels. The risk of AD in the highest quartile of plasma A[beta]42 was increased by more than twofold over that in the lowest quartile. The highest plasma A[beta]42 levels were observed in patients with AD who died during the follow-up. Plasma A[beta]42, but not A[beta]40, levels decreased over time in patients with newly acquired AD.

Conclusions: Plasma A[beta]40 and A[beta]42 increase with age and are strongly correlated with each other. Plasma A[beta]40 and A[beta]42 levels are elevated in some patients before and during the early stages of AD but decline thereafter. High plasma A[beta]42 levels may also be associated with mortality in patients with AD.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Age Distribution
  • Age Factors
  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / blood*
  • Alzheimer Disease / genetics
  • Alzheimer Disease / mortality*
  • Amyloid beta-Peptides / blood*
  • Apolipoproteins E / genetics
  • Body Mass Index
  • Female
  • Follow-Up Studies
  • Humans
  • Lipids / blood
  • Male
  • Multivariate Analysis
  • Neuropsychological Tests
  • New York City / epidemiology
  • Peptide Fragments / blood*
  • Predictive Value of Tests
  • Proportional Hazards Models
  • Risk Assessment


  • Amyloid beta-Peptides
  • Apolipoproteins E
  • Lipids
  • Peptide Fragments
  • amyloid beta-protein (1-40)
  • amyloid beta-protein (1-42)