Introduction: The present study investigated the relationship between beta-amyloid (Aβ) and cognition in a late middle-aged cohort at risk for Alzheimer's disease (AD).
Methods: One eighty-four participants (mean age = 60; 72% parental history of AD) completed a [C-11]Pittsburgh compound B positron emission tomography scan and serial cognitive evaluations. A global measure of Aβ burden was calculated, and composite scores assessing learning, delayed memory, and executive functioning were computed.
Results: Higher Aβ was associated with classification of psychometric mild cognitive impairment (MCI) at follow-up (P < .01). Linear mixed effects regression results indicated higher Aβ was associated with greater rates of decline in delayed memory (P < .01) and executive functioning (P < .05). Apolipoprotein E (APOE) ε4 status moderated the relationship between Aβ and cognitive trajectories (P values <.01).
Discussion: In individuals at risk for AD, greater Aβ in late middle age is associated with increased likelihood of MCI at follow-up and steeper rates of cognitive decline.
Keywords: APOE; Alzheimer's disease; Amyloid imaging; Cognition; Mild cognitive impairment; Preclinical Alzheimer's disease.
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