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Introduction We have previously shown that although sleep duration is similar between cognitively non-impaired (CNI) elders and patients with Mild Cognitive Impairment (MCI), long sleep duration is associated with disease severity in patients with multi-domain MCI and Dementia. Our aim was to examine the associations between sleep duration and cognitive status in subjects with CNI and MCI followed 8 years later. Methods A sub-sample of 110 participants (77.3% females) were recruited from a large population-based cohort in Crete, Greece of 3,140 older adults (>60 years). Participants with an initial diagnosis of CNI (n=57) and MCI (n=53) (mean age at baseline=72.7 years [SD=6.8]) were followed-up 8 years later (mean age at follow up=80.5 years [SD=6.7]). All participants underwent neuropsychiatric/neuropsychological evaluation (baseline & follow-up) and a 7-day 24h actigraphy (follow-up). Sleep duration measured as night Total Sleep Time (TST) at follow-up was compared between the diagnostic groups using ANCOVA controlling for age, gender, depression symptom severity, psychotropic medication. Long sleep duration was defined by values >75% percentile of the total sample distribution on each sleep index. Results At follow up 62.7% of participants have deteriorated cognitively with 29 being diagnosed with CNI, 49 with MCI and 32 with dementia. Patients with dementia had significantly longer night TST (mean=493, SD=106 min) than persons with MCI (mean=453, SD=68 min, p=0.05) who in turn had longer night TST than CNI participants (mean=409, SD=58 min, p=0.02). Also, long night sleep duration was significantly more prevalent among dementia patients and MCI compared to CNI individuals [67.7% vs. 36.7% vs. 10.3%, respectively; all p< 0.02)]. Conclusion Our study confirms and expands previous findings that objective long sleep duration is a marker of worse cognitive status in elderly with MCI or Dementia and that this association is even stronger in old-old individuals. Support (if any) National Strategic Reference Framework (NSRF)-Research Funding Program: THALES entitled “UOC-Multidisciplinary network for the study of Alzheimer’s Disease” Grant Cod: MIS 377299 HELLENIC FOUNDATION FOR REASEARCH AND INNOVATION (HFRI)- Research Funding Program: ELIDEK entitled “Sleep Apnea (OSA) and poor sleep as Risk Factors for decreased cognitive performance in patients with Mild Cognitive Impairment: the Cretan Aging Cohort (CAC)”, Grant Cod: HFR1-FM17-4397

Introduction Previous cross-sectional studies have shown that insomnia symptoms and objective short sleep are associated with disease severity in patients with Mild Cognitive Impairment (MCI) and Dementia. Our aim was to examine the longitudinal associations between sleep quality/quantity with cognitive progression in non-demented community-dwelling elderly. Methods A sub-sample of 105 participants (77.5% females) from a large population-based cohort in Crete, Greece of 3,140 older adults (>60 years; baseline) were followed up 8 years later (follow-up). All participants underwent neuropsychiatric/neuropsychological evaluation on both phases. At baseline, subjective sleep complaints and objective sleep variables based on 3-day 24 hour actigraphy were assessed. The impact of baseline objective sleep characteristics and/or insomnia (as defined by at least two subjective sleep complaints) on cognitive progression was assessed with univariate and multivariate models controlling for confounders. Results At baseline 50 participants were diagnosed as CNI and 55 as MCI; at follow-up 60 participants (57.1%) displayed clinically significant cognitive deterioration while the remaining showed relatively stable cognitive status. The frequency of persons reporting insomnia symptoms at baseline was higher among those who displayed cognitive deterioration (31.7%) than those in the cognitively stable group (13.3%, p=0.037). Logistic regression analysis showed that participants with insomnia symptoms at baseline, were significantly more likely to deteriorate cognitively at follow-up (p=0.05, OR=2.90). Also, among objective sleep variables added to the model, it was poor sleep efficiency that was associated with cognitive deterioration (p=0.035, OR=3.48). Conclusion More than half of the participants displayed significant cognitive deterioration over 8 years and this decline was predicted by insomnia symptoms and objective poor sleep efficiency at baseline. Improving both quality and quantity of sleep may significantly delay the deterioration of cognitive function in non-demented community-dwelling elderly. Support (if any) National Strategic Reference Framework (NSRF) - Research Funding Program: THALES entitled “UOC-Multidisciplinary network for the study of Alzheimer’s Disease” Grant Cod: MIS 377299 HELLENIC FOUNDATION FOR REASEARCH AND INNOVATION (HFRI)- Research Funding Program: ELIDEK entitled “Sleep Apnea (OSA) and poor sleep as Risk Factors for decreased cognitive performance in patients with Mild Cognitive Impairment: the Cretan Aging Cohort (CAC)”, Grant Cod: HFR1-FM17-4397

Introduction Sleep disturbances have been linked with cognitive decline and previous cross-sectional have shown that long sleep duration is a marker of disease severity in patients Mild Cognitive Impairment (MCI) and Dementia.Our aim was to examine the longitudinal associations between sleep quantity and quality indices and cognitive progression in non-demented community-dwelling elderly. Methods A sub-sample of 62 participants (72.6% females) were recruited from a large population-based cohort in the island of Crete, Greece of 3,140 older adults (>60yrs). Participants were followed-up 8 years later (phase III). All participants underwent neuropsychiatric/neuropsychological evaluation (phases II & III) and a 3-day 24h actigraphy (phase II).Participants were diagnosed as CNI(N=38) and MCI(N=24) during phase II, and CNI (N=22), MCI (N=27) and Dementia (N=13) during phase III. On follow-up, 28 participants progressed to a cognitively declined diagnosis compared to phase II (deteriorated group), while 34 did not (non-deteriorated group). Objective sleep variables at phase II were compared between the deteriotated/non-deteriorated groups using ANCOVA controlling for confounders. Also, differences in neuropsychological testing scores (phase II- phase III) were calculated and associations of differences with sleep variables were examined using partial correlation models controlling for confounders. Results The deteriorated group compared to non-deteriorated had significantly longer night total sleep time (TST) (442±72.6min vs. 407±53.6min, p=0.033), 24h-TST (484±8.9min vs. 434±66.4min, p=0.008), night time in bed (TMB) (537±78.7min vs. 497±62.7min, p=0.03), and 24h-TMB (603±85min vs. 539±85min, p=0.005). Episodic memory worsening was moderately correlated with night TST (r=.316), night and 24h-TMB (r=.526, and r= .442 respectively), wake time after sleep onset (r=.351), and average duration of night awakenings (r=.405). Immediate episodic memory recall decline was positively correlated with night TMB (r=.338). Conclusion Preliminary results from the Cretan aging cohort indicate that almost half of the participants deteriorated cognitively in 8 years and this decline was predicted by objective sleep duration at baseline. Long sleep at baseline may predict deterioration of clinical cognitive status in non-demented elderly at follow-up. It appears that prolonged objective sleep duration and time in bed are novel and clinically useful prognostic factors of cognitive deterioration in elderly with or without cognitive deficits. Support (If Any) National Strategic Reference Framework (NSRF) - Research Funding Program: THALES entitled “UOC-Multidisciplinary network for the study of Alzheimer’s Disease” Grant Cod: MIS 377299HELLENIC FOUNDATION FOR REASEARCH AND INNOVATION (HFRI)- Research Funding Program: ELIDEK entitled “Sleep Apnea (OSA) and poor sleep as Risk Factors for decreased cognitive performance in patients with Mild Cognitive Impairment: the Cretan Aging Cohort (CAC)”, Grant Cod: HFR1-FM17-4397