Kumar B Rajan1, Robert S Wilson2,3,4, Lisa L Barnes2,3,4, Neelum T Aggarwal2,3,4, Jennifer Weuve1, Denis A Evans1. 1. Department of Internal Medicine, Rush Institute for Healthy Aging. 2. Rush Alzheimer's Disease Center. 3. Department of Neurological Sciences, and. 4. Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois.
Abstract
Background: Cognitive changes during the preclinical phase of Alzheimer's disease (AD) dementia have been characterized among European Americans (EAs), but studies of preclinical changes among African Americans (AAs) are notably absent. Methods: Preclinical changes in cognition before the development of AD dementia and mild cognitive impairment over a period of 18 years were examined using change points in a biracial sample of 2,125 older adults. Results: Of 2,125 participants, 442 (21%) developed AD dementia and 661 (31%) developed mild cognitive impairment. A cognitive change point occurred between 4 and 5 years before the clinical diagnosis of AD dementia. Differences between AAs and EAs were observed: EAs had a higher starting level of composite cognitive function, and a change point occurred 4.3 years before AD dementia among AAs and 4.7 years among EAs. The slope of cognitive decline after the change point among those developing clinical AD dementia was significantly greater among EAs (0.233 units/y) than among AAs (0.171 units/y; p < .001). This difference in slope of cognitive decline persisted after diagnosis of AD dementia so that at the conclusion of observation the difference in average cognitive level was reversed. AAs without cognitive impairment had a lower average baseline of cognition than EAs, but the slopes of cognitive decline were similar. Conclusions: A prominent change to a steeper slope of cognitive decline occurs between 4 and 5 years prior to the diagnosis of AD dementia. The slope of cognitive decline after the change point is steeper among EAs than AAs.
Background: Cognitive changes during the preclinical phase of Alzheimer's disease (AD) dementia have been characterized among European Americans (EAs), but studies of preclinical changes among African Americans (AAs) are notably absent. Methods: Preclinical changes in cognition before the development of AD dementia and mild cognitive impairment over a period of 18 years were examined using change points in a biracial sample of 2,125 older adults. Results: Of 2,125 participants, 442 (21%) developed AD dementia and 661 (31%) developed mild cognitive impairment. A cognitive change point occurred between 4 and 5 years before the clinical diagnosis of AD dementia. Differences between AAs and EAs were observed: EAs had a higher starting level of composite cognitive function, and a change point occurred 4.3 years before AD dementia among AAs and 4.7 years among EAs. The slope of cognitive decline after the change point among those developing clinical AD dementia was significantly greater among EAs (0.233 units/y) than among AAs (0.171 units/y; p < .001). This difference in slope of cognitive decline persisted after diagnosis of AD dementia so that at the conclusion of observation the difference in average cognitive level was reversed. AAs without cognitive impairment had a lower average baseline of cognition than EAs, but the slopes of cognitive decline were similar. Conclusions: A prominent change to a steeper slope of cognitive decline occurs between 4 and 5 years prior to the diagnosis of AD dementia. The slope of cognitive decline after the change point is steeper among EAs than AAs.
Authors: R S Wilson; D A Bennett; J L Bienias; N T Aggarwal; C F Mendes De Leon; M C Morris; J A Schneider; D A Evans Journal: Neurology Date: 2002-12-24 Impact factor: 9.910
Authors: Arun S Karlamangla; Dana Miller-Martinez; Carol S Aneshensel; Teresa E Seeman; Richard G Wight; Joshua Chodosh Journal: Am J Epidemiol Date: 2009-07-15 Impact factor: 4.897
Authors: Fredric D Wolinsky; Suzanne E Bentler; Jason Hockenberry; Michael P Jones; Paula A Weigel; Brian Kaskie; Robert B Wallace Journal: BMC Public Health Date: 2011-09-20 Impact factor: 3.295
Authors: Robert S Wilson; Kumar B Rajan; Lisa L Barnes; Willemijn Jansen; Priscilla Amofa; Jennifer Weuve; Denis A Evans Journal: Neuropsychol Dev Cogn B Aging Neuropsychol Cogn Date: 2017-03-23
Authors: Jennifer Weuve; Kumar B Rajan; Lisa L Barnes; Robert S Wilson; Denis A Evans Journal: J Gerontol B Psychol Sci Soc Sci Date: 2018-04-16 Impact factor: 4.077
Authors: Seonjoo Lee; Xingtao Zhou; Yizhe Gao; Badri Vardarajan; Dolly Reyes-Dumeyer; Kumar B Rajan; Robert S Wilson; Denis A Evans; Lilah M Besser; Walter A Kukull; David A Bennett; Adam M Brickman; Nicole Schupf; Richard Mayeux; Sandra Barral Journal: PLoS One Date: 2018-11-21 Impact factor: 3.240