Article

Cerebrospinal Fluid Biomarkers, Education, Brain Volume, and Future Cognition

Knight Alzheimer’s Disease Research Center, St Louis, MO, USA.
Archives of neurology (Impact Factor: 7.42). 09/2011; 68(9):1145-51. DOI: 10.1001/archneurol.2011.192
Source: PubMed

ABSTRACT

Cross-sectional studies suggest that the cognitive impact of Alzheimer disease pathology varies depending on education and brain size.
To evaluate the combination of cerebrospinal fluid biomarkers of β-amyloid(42) (Aβ(42)), tau, and phosphorylated tau (ptau(181)) with education and normalized whole-brain volume (nWBV) to predict incident cognitive impairment.
Longitudinal cohort study.
Charles F. and Joanne Knight Alzheimer's Disease Research Center, Washington University, St Louis, Missouri.
A convenience sample of 197 individuals 50 years and older with normal cognition (Clinical Dementia Rating of 0) at baseline observed for a mean of 3.3 years.
Time to Clinical Dementia Rating ≥ 0.5.
Three-factor interactions among the baseline biomarker values, education, and nWBV were found for Cox proportional hazards regression models testing tau (P = .02) and ptau (P = .008). In those with lower tau values, nWBV (hazard ratio [HR], 0.54; 95% confidence interval [CI], 0.31-0.91; P = .02), but not education, was related to time to cognitive impairment. For participants with higher tau values, education interacted with nWBV to predict incident impairment (P = .01). For individuals with lower ptau values, there was no effect of education or nWBV. Education interacted with nWBV to predict incident cognitive impairment in those with higher ptau values (P = .02).
In individuals with normal cognition and higher levels of cerebrospinal fluid tau and ptau at baseline, time to incident cognitive impairment is moderated by education and brain volume as predicted by the cognitive/brain reserve hypothesis.

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    • "The present study reports on individuals who were primarily middleaged at baseline (mean age, 56.9 years) and have been followed for up to 17 years (mean, 8 years). Third, previous longitudinal studies (Roe et al., 2011a; Yaffe et al., 2011) have used education as a proxy for CR, although education is static and unlikely to change after early adulthood. The present study used a composite measure of CR based on not only education but also literacy and vocabulary, which may change over the lifetime and be a better reflection of CR (Manly et al., 2003, 2005). "
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