Evaluating Alzheimer's disease biomarkers as mediators of age-related cognitive decline

Alzheimer's Neuroimaging Initiative

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Age-related changes in cognition are partially mediated by the presence of neuropathology and neurodegeneration. This manuscript evaluates the degree to which biomarkers of Alzheimer's disease, (AD) neuropathology and longitudinal changes in brain structure, account for age-related differences in cognition. Data from the AD Neuroimaging Initiative (n = 1012) were analyzed, including individuals with normal cognition and mild cognitive impairment. Parallel process mixed effects regression models characterized longitudinal trajectories of cognitive variables and time-varying changes in brain volumes. Baseline age was associated with both memory and executive function at baseline (p's < 0.001) and change in memory and executive function performances over time (p's < 0.05). After adjusting for clinical diagnosis, baseline, and longitudinal changes in brain volume, and baseline levels of cerebrospinal fluid biomarkers, age effects on change in episodic memory and executive function were fully attenuated, age effects on baseline memory were substantially attenuated, but an association remained between age and baseline executive function. Results support previous studies that show that age effects on cognitive decline are fully mediated by disease and neurodegeneration variables but also show domain-specific age effects on baseline cognition, specifically an age pathway to executive function that is independent of brain and disease pathways.

Original languageEnglish (US)
Pages (from-to)120-128
Number of pages9
JournalNeurobiology of Aging
StatePublished - Oct 1 2017


  • Cognition
  • CSF biomarkers
  • Longitudinal modeling
  • MRI
  • Parallel process model
  • Structural imaging

ASJC Scopus subject areas

  • Neuroscience(all)
  • Aging
  • Developmental Biology
  • Geriatrics and Gerontology
  • Clinical Neurology


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