title: Effect of Cognitive Reserve on Age-Related Changes in Cerebrospinal Fluid Biomarkers of Alzheimer Disease.
abstract: OBJECTIVE
  Although advancing age is the strongest risk factor for the development of symptomatic Alzheimer disease (AD), recent studies have shown that there are individual differences in susceptibility to age-related alterations in the biomarkers of AD pathophysiology.
  
  
  OBJECTIVE
  To investigate whether cognitive reserve (CR) modifies the adverse influence of age on key cerebrospinal fluid (CSF) biomarkers of AD.
  
  
  METHODS
  A cross-sectional cohort of 268 individuals (211 in a cognitively normal group and 57 in a cognitively impaired group) from the Wisconsin Registry for Alzheimer's Prevention and the Wisconsin Alzheimer's Disease Research Center participated in this study. They underwent lumbar puncture for collection of CSF samples, from which Aβ42, total tau (t-tau), and phosphorylated tau (p-tau) were immunoassayed. In addition, we computed t-tau/Aβ42 and p-tau/Aβ42 ratios. Cognitive reserve was indexed by years of education, with 16 or more years taken to confer high reserve. Covariate-adjusted regression analyses were used to test whether the effect of age on CSF biomarkers was modified by CR. The study dates were March 5, 2010, to February 13, 2013.
  
  
  METHODS
  Cerebrospinal fluid levels of Aβ42, t-tau, p-tau, t-tau/Aβ42, and p-tau/Aβ42.
  
  
  RESULTS
  There were significant age × CR interactions for CSF t-tau (β [SE] = -6.72 [2.84], P = .02), p-tau (β [SE] = -0.71 [0.27], P = .01), t-tau/Aβ42 (β [SE] = -0.02 [0.01], P = .02), and p-tau/Aβ42 (β [SE] = -0.002 [0.001], P = .004). With advancing age, individuals with high CR exhibited attenuated adverse alterations in these CSF biomarkers compared with individuals with low CR. This attenuation of age effects by CR tended to be more pronounced in the cognitively impaired group compared with the cognitively normal group. There was evidence of a dose-response relationship such that the effect of age on the biomarkers was progressively attenuated given additional years of schooling.
  
  
  CONCLUSIONS
  In a sample composed of a cognitively normal group and a cognitively impaired group, higher CR was associated with a diminution of age-related alterations in CSF biomarkers of AD. This suggests one pathway through which CR might favorably alter lifetime risk for symptomatic AD.
authors.affiliation: Currently a student at Fluminense Federal University, Niteroi, Brazil2Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin3Wisconsin Alzheimer's Institute, University of Wisconsin School of.
authors.forename: Rodrigo P
authors.initials: RP
authors.lastname: Almeida
authors.affiliation: Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin3Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison4Wisconsin Alzheimer's Disease Rese.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Schultz
authors.affiliation: Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin4Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison.
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Austin
authors.affiliation: Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin3Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison4Wisconsin Alzheimer's Disease Rese.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Boots
authors.affiliation: Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison5Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison6Department of N.
authors.forename: N Maritza
authors.initials: NM
authors.lastname: Dowling
authors.affiliation: Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin4Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison.
authors.forename: Carey E
authors.initials: CE
authors.lastname: Gleason
authors.affiliation: Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin3Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison4Wisconsin Alzheimer's Disease Rese.
authors.forename: Barbara B
authors.initials: BB
authors.lastname: Bendlin
authors.affiliation: Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison4Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Sager
authors.affiliation: Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison4Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison6Department of Neurology, University.
authors.forename: Bruce P
authors.initials: BP
authors.lastname: Hermann
authors.affiliation: Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden8University of London Institute of Neurology, Queen Square, London, England.
authors.forename: Henrik
authors.initials: H
authors.lastname: Zetterberg
authors.affiliation: Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin4Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison.
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Carlsson
authors.affiliation: Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin3Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison4Wisconsin Alzheimer's Disease Rese.
authors.forename: Sterling C
authors.initials: SC
authors.lastname: Johnson
authors.affiliation: Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin3Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison4Wisconsin Alzheimer's Disease Rese.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Asthana
authors.affiliation: Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin3Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison4Wisconsin Alzheimer's Disease Rese.
authors.forename: Ozioma C
authors.initials: OC
authors.lastname: Okonkwo
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000134:cerebrospinal fluid* / Q000503:physiopathology; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid*; D015415:Biomarkers / Q000134:cerebrospinal fluid; D058245:Cognitive Reserve / Q000502:physiology*; D003430:Cross-Sectional Studies; D004522:Educational Status; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000134:cerebrospinal fluid*; D012042:Registries; D016875:tau Proteins / Q000134:cerebrospinal fluid*
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D016875:tau Proteins