Dataset Information

Association Between Elevated Brain Amyloid and Subsequent Cognitive Decline Among Cognitively Normal Persons.

ABSTRACT: Among cognitively normal individuals, elevated brain amyloid (defined by cerebrospinal fluid assays or positron emission tomography regional summaries) can be related to risk for later Alzheimer-related cognitive decline.To characterize and quantify the risk for Alzheimer-related cognitive decline among cognitively normal individuals with elevated brain amyloid.Exploratory analyses were conducted with longitudinal cognitive and biomarker data from 445 cognitively normal individuals in the United States and Canada. Participants were observed from August 23, 2005, to June 7, 2016, for a median of 3.1 years (interquartile range, 2.0-4.2 years; maximum follow-up, 10.3 years) as part of the Alzheimer's Disease Neuroimaging Initiative (ADNI).Individuals were classified at baseline as having normal (n?=?243) or elevated (n?=?202) brain amyloid using positron emission tomography amyloid imaging or a cerebrospinal fluid assay of amyloid ?.Outcomes included scores on the Preclinical Alzheimer Cognitive Composite (PACC; a sum of 4 baseline standardized z scores, which decreases with worse performance), Mini-Mental State Examination (MMSE; 0 [worst] to 30 [best] points), Clinical Dementia Rating Sum of Boxes (CDR-Sum of Boxes; 0 [best] to 18 [worst] points), and Logical Memory Delayed Recall (0 [worst] to 25 [best] story units).Among the 445 participants (243 with normal amyloid, 202 with elevated amyloid), mean (SD) age was 74.0 (5.9) years, mean education was 16.4 (2.7) years, and 52% were women. The mean score for PACC at baseline was 0.00 (2.60); for MMSE, 29.0 (1.2); for CDR-Sum of Boxes, 0.04 (0.14); and for Logical Memory Delayed Recall, 13.1 (3.3). Compared with the group with normal amyloid, those with elevated amyloid had worse mean scores at 4 years on the PACC (mean difference, 1.51 points [95% CI, 0.94-2.10]; P?

SUBMITTER: Donohue MC

PROVIDER: S-EPMC5736301 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

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Association Between Elevated Brain Amyloid and Subsequent Cognitive Decline Among Cognitively Normal Persons.

Donohue Michael C MC Sperling Reisa A RA Petersen Ronald R Sun Chung-Kai CK Weiner Michael W MW Aisen Paul S PS

JAMA 20170601 22

<h4>Importance</h4>Among cognitively normal individuals, elevated brain amyloid (defined by cerebrospinal fluid assays or positron emission tomography regional summaries) can be related to risk for later Alzheimer-related cognitive decline.<h4>Objective</h4>To characterize and quantify the risk for Alzheimer-related cognitive decline among cognitively normal individuals with elevated brain amyloid.<h4>Design, setting, and participants</h4>Exploratory analyses were conducted with longitudinal cog ...[more]

PMID: 28609533

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Project description:ObjectivesRecent studies regarding the relationships between plasma amyloid-β (Aβ) levels and cognitive performance had inconsistent results. In this study, we aimed to characterize the relationship between cognitive decline and plasma Aβ levels in a large-sample cognitively normal population.MethodsThis population-based, prospective cohort study included 1,240 participants with normal cognition. The Mini-Mental State Examination (MMSE) was used to assess cognitive function at baseline and 2 years later. Restricted cubic splines, multivariate logistic regression, and multivariate linear regression models were used to evaluate the type of relationship between cognitive decline during the 2-year follow-up period and plasma Aβ levels (Aβ40, Aβ42, and Aβ42 / 40).ResultsParticipants with moderate Aβ40 levels had the highest risk of cognitive decline during a 2-year follow-up relative to individuals with low Aβ40 [odds ratio (OR): 0.60, 95% confidence interval (CI): 0.45-0.81, p < 0.001] or high Aβ40 (OR: 0.65, 95% CI: 0.49-0.87, p = 0.004) levels. The association between Aβ40 and cognitive decline did not depend on sex, education level, or APOE ε4 status. There was an interaction found between age (≤ 65 and > 65 years) and Aβ40 (p for interaction = 0.021). In individuals older than 65 years, there was a positive linear relationship between plasma Aβ40 and cognitive decline (OR: 1.02, 95% CI: 1.00-1.04, p = 0.027). For participants ≤ 65 years old, the lower Aβ40 and higher Aβ40 groups had a lower risk of cognitive decline than the medium Aβ40 group (OR: 0.69, 95% CI: 0.50-0.94, p = 0.02; OR: 0.63, 95% CI: 0.45-0.86, p = 0.004). None of relationship between plasma Aβ42, Aβ42 / 40 and cognitive decline was found during a 2-year follow-up.ConclusionThe relationship between plasma Aβ40 and cognitive decline was not linear, but an inverted-U shape in a cognitively normal population. The underlying mechanism requires further investigation.

Project description:ImportanceThe role of amyloid in the progression of Alzheimer disease (AD) pathophysiology is of central interest to the design of randomized clinical trials. The presence of amyloid has become a prerequisite for enrollment in several secondary prevention trials for AD, yet the precise effect of elevated amyloid levels on subsequent clinical and biomarker events is less certain.ObjectiveTo explore the effect of elevated amyloid levels on subsequent changes in cognition and biomarkers.Design, setting, and participantsA total of 564 cognitively normal individuals (median age, 78 years) from the Mayo Clinic Study of Aging, a population-based longitudinal study in Olmsted County, Minnesota, with serial cognitive data were selected for this study. The data used in this study were collected from January 12, 2006, to January 9, 2014. Individuals included in this study had undergone magnetic resonance imaging, fluorodeoxyglucose positron emission tomography (FDG-PET), and Pittsburgh Compound B (PiB) PET at baseline were not cognitively impaired at baseline and had at least 1 clinical follow-up. A subset of 286 individuals also underwent serial imaging. Elevated amyloid level was defined as a standardized uptake value ratio of greater than 1.5 on PiB PET. Associations with baseline amyloid status and baseline and longitudinal change in clinical and imaging measures were evaluated after adjusting for age and hippocampal volume. APOE4 effects were also evaluated.Main outcomes and measuresCognitive measures of memory, language, attention/executive function, visuospatial skills, PiB levels, hippocampal and ventricular volumes, and FDG-PET measures.ResultsAt baseline, 179 (31.7%) individuals with elevated amyloid levels had poorer cognition in all domains measured, reduced hippocampal volume, and greater FDG-PET hypometabolism. Elevated amyloid levels at baseline were associated with a greater rate of cognitive decline in all domains (0.04 to 0.09 z score units per year) except language and a greater rate of amyloid accumulation (1.6% per year), hippocampal atrophy (30 mm3 per year), and ventricular enlargement (565 mm3 per year). Elevated amyloid levels were also associated with an increased risk of mild cognitive impairment (hazard ratio, 2.9; 95% CI, 1.7-5.0, and hazard ratio, 1.6; 95% CI, 0.9-2.8, for PiB+ APOE4 carriers and PiB+ noncarriers, respectively, compared with PiB- noncarriers). These associations were largely independent of APOE4.Conclusions and relevanceIn persons selected from a population-based study, elevated amyloid levels at baseline were associated with worse cognition and imaging biomarkers at baseline and with greater clinical decline and neurodegeneration. These results have implications for the design of randomized clinical trials for AD.

Project description:Importance:To reduce the rising incidence of clinical impairment due to Alzheimer disease, it is essential to define older adults at highest risk. Widowhood may be an unrecognized factor contributing to accelerated clinical progression along the Alzheimer disease pathway among cognitively unimpaired older adults. Objective:To determine whether widowhood status and level of brain ?-amyloid (ie, the Alzheimer disease pathologic protein) are additively or interactively associated with cognitive decline among cognitively unimpaired older adults. Design, Setting, and Participants:In this cohort study, 257 married, widowed, and unmarried (ie, never married, divorced, or separated) participants from the Harvard Aging Brain Study longitudinal cohort underwent baseline evaluation of neocortical ?-amyloid levels using Pittsburgh compound B positron emission tomography and 4 annual cognitive assessments. Data were collected from September 2010 to February 2017 and analyzed from July 2018 to July 2019. Main Outcomes and Measures:Cognitive performance was measured using the Preclinical Alzheimer Cognitive Composite. Results:Of the 257 participants, 153 (59.5%) were women, and the mean (SD) age was 73.5 (6.1) years; 145 participants (56.4%) were married (66 [45.5%] women), 77 (30.0%) were unmarried (56 [72.7%] women), and 35 (13.6%) were widowed (31 [88.6%] women). Compared with married participants, widowed participants demonstrated worsening cognitive performance after adjusting for age, sex, socioeconomic status, depression, and ?-amyloid levels (??=?-0.11; 95% CI, -0.19 to -0.04; P?=?.002) with no difference observed between married and unmarried participants. Furthermore, widowed participants with higher baseline ?-amyloid levels exhibited steeper cognitive decline (??=?-0.22; 95% CI, -0.42 to -0.03; P?=?.02), indicating both independent and interactive associations of ?-amyloid levels and widowhood with cognition. In a secondary model using dichotomous ?-amyloid-marital status groupings, the rate of cognitive decline among widowed participants with high ?-amyloid was nearly 3 times faster than among married participants with high ?-amyloid (widowed, high ?-amyloid: ?, -0.33; 95% CI, -0.46 to -0.19; P?<?.001; married, high ?-amyloid: ?, -0.12; 95% CI, -0.18 to -0.01; P?<?.001). Conclusions and Relevance:In a sample of cognitively unimpaired older adults, being widowed was associated with accelerated ?-amyloid-related cognitive decline during 3 years. Cognitively unimpaired, widowed older adults were particularly susceptible to Alzheimer disease clinical progression, emphasizing the need for increased research attention and evidenced-based interventions for this high-risk group.

Dataset Information

Association Between Elevated Brain Amyloid and Subsequent Cognitive Decline Among Cognitively Normal Persons.

Publications

Association Between Elevated Brain Amyloid and Subsequent Cognitive Decline Among Cognitively Normal Persons.

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