The presence of brain amyloid is preceded by accelerated cognitive decline in non-demented older adults: Results from a multi-ethnic population

189 Objectives Alzheimer disease has been shown to be preceded by accelerated decline in multiple cognitive functions. We aimed to examine whether a positive or higher level of brain amyloid-β (Aβ) deposition is preceded by a faster cognitive decline. Methods Ninety-eight dementia-free participants (mean age 84 years) of Washington Heights Inwood Columbia Aging Project completed F-18-florbetaben PET imaging. Positive or negative F-18-florbetaben binding to cerebral Aβ deposition was assessed visually. Quantitative cerebral Aβ burden was calculated as the standardized uptake value ratio in pre-established regions of interest using cerebellar cortex as the reference region. We examined cross-sectional associations between Aβ deposition status or burden and composite cognitive scores in memory, language, speed and visuospatial domains and mean score. We also examined longitudinal cognition change up to14 years before PET scan using latent growth curve models. Results There was no cross-sectional association between any of the cognitive scores and PET Aβ after controlling for age, gender, education, ethnicity, and APOE ϵ4 genotype. Aβ positive elders declined in processing speed faster relative to Aβ negative elders (B=-0.052, p=0.01). Similarly, higher Aβ burden in the frontal (B=-0.067, p=0.04) and temporal (B=-0.075, p=0.03) regions was associated with faster decline in processing speed. Higher Aβ deposition was associated with faster longitudinal declines in overall cognition, language and speed in Blacks, and higher Aβ deposition was associated with faster longitudinal declines in overall cognition and memory scores in APOE ϵ4 carriers. Conclusions High Aβ deposition in old adults is associated with faster cognitive decline in the preceding decade, and the association might vary by ethnic groups and APOE ϵ4 genotype. Research Support (NIH) AG07232 and Piramal Life Sciences