Abstract
Objective: To identify self-reported sleep-wake disturbances that increase the risk of cognitive decline over 1-year follow-up in frail participants.Background: Risk factors for cognitive impairment need to be better identified especially at earliest stages of the pathogenesis. Sleep-wake disturbances may be critical factors to consider and were thus being assessed in this at-risk population for cognitive decline.Methods: Frail elderly participants aged ≥70 years were selected from a subsample of the Multi-domain Alzheimer Preventive Trial (MAPT) for a sleep assessment (MAPT-sleep study) at 18-month follow-up (M18). Sleep-wake disturbances were evaluated using a clinical interview (duration of daytime and nighttime sleep, time in bed, number of naps, and presence of clinically-defined sleep disorders) and numerous validated questionnaires [Epworth Sleepiness Scale for excessive daytime sleepiness (EDS), Insomnia Severity Scale and Berlin Questionnaire]. Cognitive decline was defined as a difference between the MMSE and cognitive composite scores at M24 and M36 that was ranked in the lowest decile. Multivariate logistic regression models adjusted for several potential confounding factors were performed.Results: Among the 479 frail participants, 63 developed MMSE-cognitive decline and 50 cognitive composite score decrease between M24 and M36. Subjects with EDS had an increased risk of MMSE decline (OR = 2.46; 95% CI [1.28; 4.71], p = 0.007). A longer time spent in bed during night was associated with cognitive composite score decline (OR = 1.32 [1.03; 1.71], p = 0.03). These associations persisted when controlling for potential confounders. Patients with MMSE score decline and EDS had more naps, clinically-defined REM-sleep Behavior Disorder, fatigue and insomnia symptoms, while patients with cognitive composite score decline with longer time in bed had increased 24-h total sleep time duration but with higher wake time after onset.Conclusions: The risk of cognitive decline is higher in frailty subjects with EDS and longer nighttime in bed. Early detection of sleep-wake disturbances might help identifying frail subjects at risk of cognitive decline to further propose sleep health strategies to prevent cognitive impairment.http://www.clinicaltrials.gov NCT00672685; Date of registration May, 2nd 2008.
Highlights
Age-related cognition and sleep-wake pattern changes vary considerably across individuals (Virta et al, 2013; Yaffe et al, 2014)
Some longitudinal population-based and clinical-based cohort studies confirmed these associations with disturbed nighttime sleep, shorter or longer nighttime sleep duration and excessive daytime sleepiness (EDS) being all predictors of cognitive decline (Foley et al, 2001; Jaussent et al, 2012; Keage et al, 2012; Benito-Leon et al, 2013)
We evaluated the association between self-reported sleep-wake disturbances and cognitive status assessed with the Mini Mental State Examination (MMSE) test and a cognitive composite score in frail subjects aged 70 years and older over 1-year follow-up by taking into account many confounding factors
Summary
Age-related cognition and sleep-wake pattern changes vary considerably across individuals (Virta et al, 2013; Yaffe et al, 2014). Other studies failed to validate some of these associations (Tworoger et al, 2006; Johar et al, 2016; Ramos et al, 2016) These contrasting findings could be explained by differences in the targeted populations (size, sex and age), follow-up period duration, cognitive tests, baseline cognitive status, sleep-wake assessment, sleep profile of participants, and control of potential confounders. Sleep-wake pattern alterations progressively increase with age, especially in elderly individuals with mild cognitive impairment (MCI), AD or at risk of AD (APOEε4 allele carriers) (Spira et al, 2013; Osorio et al, 2014; Sprecher et al, 2015; Branger et al, 2016; Drogos et al, 2016). Only few studies prospectively confirmed using validated sleep questionnaires the presence of sleep disorders and determined precisely the spectrum of sleepwake profiles at risk factor for cognitive impairment. Sleep-wake disturbances may be critical factors to consider and were being assessed in this at-risk population for cognitive decline
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