Hayden K.M.,Duke University |
Reed B.R.,University of California at Davis |
Reed B.R.,VA Northern California Health Care System |
Manly J.J.,The Taub Institute for Research on Alzheimers Disease and The Aging Brain |
And 7 more authors.
Age and Ageing | Year: 2011
Background: Studies of cognitive ageing at the group level suggest that age is associated with cognitive decline; however, there may be individual differences such that not all older adults will experience cognitive decline. Objective: to evaluate patterns of cognitive decline in a cohort of older adults initially free of dementia. Design, setting and subjects: elderly Catholic clergy members participating in the Religious Orders Study were followed for up to 15 years. Cognitive performance was assessed annually. Methods: performance on a composite global measure of cognition was analysed using random effects models for baseline performance and change over time. A profile mixture component was used to identify subgroups with different cognitive trajectories over the study period. Results: from a sample of 1,049 participants (mean age 75 years), three subgroups were identified based on the distribution of baseline performance and change over time. The majority (65%) of participants belonged to a slow decline class that did not experience substantial cognitive decline over the observation period [-0.04 baseline total sample standard deviation (SD) units/year]. About 27% experienced moderate decline (-0.19 SD/year), and 8% belonged to a class experiencing rapid decline (-0.57 SD/year). A subsample analysis revealed that when substantial cognitive decline does occur, the magnitude and rate of decline is correlated with neuropathological processes. Conclusions: in this sample, the most common pattern of cognitive decline is extremely slow, perceptible on a time scale measured by decades, not years. While in need of cross validation, these findings suggest that cognitive changes associated with ageing may be minimal and emphasise the importance of understanding the full range of age-related pathologies that may diminish brain function. © The Author 2011. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved.
PubMed | Fordham University, New York Medical College, The Taub Institute for Research on Alzheimers Disease and the Aging Brain and Columbia University
Type: Journal Article | Journal: Dementia and geriatric cognitive disorders extra | Year: 2015
To examine the association between self-reported sleep problems and incidence of dementia in community-dwelling elderly people.1,041 nondemented participants over 65 years old were examined longitudinally. Sleep problems were estimated using the RAND Medical Outcomes Study Sleep Scale examining sleep disturbance, snoring, sleep short of breath or with a headache, sleep adequacy, and sleep somnolence. Cox regression analysis was used to examine the association between sleep problems and risk for incident dementia. Age, gender, education, ethnicity, APOE-4, stroke, heart disease, hypertension, diabetes, and depression were included as covariates.Over 3 years of follow-up, 966 (92.8%) participants remained nondemented, while 78 (7.2%) developed dementia. In unadjusted models, sleep inadequacy (Get the amount of sleep you need) at the initial visit was associated with increased risk of incident dementia (HR = 1.20; 95% CI 1.02-1.42; p = 0.027). Adjusting for all the covariates, increased risk of incident dementia was still associated with sleep inadequacy (HR = 1.20; 95% CI 1.01-1.42; p = 0.040), as well as with increased daytime sleepiness (Have trouble staying awake during the day) (HR = 1.24; 95% CI 1.00-1.54; p = 0.047).Our results suggest that sleep inadequacy and increased daytime sleepiness are risk factors for dementia in older adults, independent of demographic and clinical factors.