J Sleep Res

Many studies suggest a relationship between excessive daytime sleepiness (EDS) and dementia incidence, but the underlying mechanisms remain uncertain. The study aimed to investigate the role of cardiovascular burden in the relationship between EDS and dementia incidence over a 12-year follow-up in community-dwelling older adults. We performed analyses on 6171 subjects (aged ≥65 years) free of dementia and vascular disease at baseline. Participants self-reported EDS at baseline and an expert committee validated both prevalent and incident dementia. We defined cardiovascular burden by a low Cardiovascular Health score, constructed using the American Heart Association metrics, and incident vascular events. To explore the potential role of the cardiovascular burden in the relationship between EDS and dementia, we conducted mediation analyses with inverse odds ratio-weighted estimation, using multivariable-adjusted proportional hazard Cox and logistic regression models. Subjects with EDS had a higher risk of all-cause dementia (hazard ratio [HR] 1.39, 95% confidence interval [CI] 1.13-1.69) and dementia with vascular component (DVC) (HR 2.14, 95% CI 1.30-3.51), but not Alzheimer's disease (HR 1.18, 95% CI 0.93-1.51). Cardiovascular burden explained 5% (95% CI 4.1-5.2) and 11% (95% CI 9.7-11.3) of the relationship between EDS and all-cause dementia and DVC, respectively. These findings confirm that EDS may be implicated in the development of dementia and indicate a weaker than expected role of cardiovascular burden in the relationship between EDS and DVC.COGINUT : Cognition, anti-oxydants, acides gras: approche interdisciplinaire du rôle de la nutrition dans le vieillissement du cerveauInteraction entre la vulnérabilité génétique, la dysrégulation biologique et le stress dans la dépression du sujet âg

Complaints of daytime sleepiness, insomnia, hypnotic use, and risk of dementia: a prospective cohort study in the elderly

International audienceBACKGROUND: Sleep disturbances are common in elderly and occur frequently in dementia. The impact of excessive daytime sleepiness (EDS), insomnia complaints, sleep quality, and hypnotics on the risk of all-cause dementia, Alzheimer disease (AD), and dementia with vascular component (DVC) remains unclear, as does the association between sleep profile and plasma β-amyloid levels. METHODS: Analyses were carried out on 6851 participants aged 65 years and over randomly recruited from three French cities and free of dementia at baseline. A structured interview and self-questionnaire assessed sleep complaints (EDS, insomnia complaints, sleep quality) and medications at baseline. Incident cases of dementia were diagnosed systematically over a 12-year period. Multivariate Cox models were used to estimate the risk of dementia associated with the sleep complaints considered individually and globally. Plasma β-amyloid levels were measured by an xMAP-based assay technology in 984 subjects. RESULTS: After adjustment for socio-demographic characteristics, lifestyle, APOE-ε4, cardiovascular factors, and depressive status, EDS had a higher risk of all-cause dementia (HR = 1.21; 95%CI = [1.01-1.46]) and DVC (HR = 1.58; 95%CI = [1.07-2.32]) but not AD. Persistent use of hypnotics increased the risk for all-cause dementia, specifically AD (HR = 1.28; 95%CI = [1.04-1.58]), but not DVC. No association was found for insomnia complaints and sleep quality taken as individual factors or combined with EDS on the risk of dementia. No association was found between β-amyloid, sleep complaints, and incident dementia. CONCLUSIONS: The results suggest a deleterious role of EDS and hypnotics on dementia. Further studies are required to elucidate the mechanisms involved in these associations and whether its management can prevent the risk of dementia

Trajectories of sleep duration and timing before dementia: a 14-year follow-up study

BACKGROUND: given the complex relationship between sleep and neurodegenerative processes, it is important to examine whether changes in sleep patterns occur prior or close to dementia onset. OBJECTIVE: to examine the relationship between sleep parameters and dementia incidence and, to characterize trajectories of sleep patterns before dementia diagnosis. DESIGN: a 14-year longitudinal study including a nested case-control study. SETTING: the French Three-City Study. SUBJECTS: overall, 1,749 cognitively healthy participants (>/=65 years) for the longitudinal study and, 182 incident dementia cases and 719 controls matched by sex, age and educational level for the case-control study. METHODS: dementia cases were assessed at each visit and self-reported sleep parameters at baseline, 2, 8, 10, 12 and 14 years. Cox models were used to estimate the risk of dementia associated with baseline sleep parameters (sleep duration, time in bed (TIB), sleep timing, sleepiness and insomnia). Latent-process mixed models were performed to compare sleep trajectories according to the case-control status. RESULTS: long baseline nighttime and 24-h sleep durations (>/=9 h) as well as being persistent or becoming long sleepers during follow-up were associated with dementia incidence. Trajectories of sleep durations and TIB showed faster increases in cases compared with controls up to 12 years before dementia. The mean differences [95%CI] for 24-h sleep duration between cases and controls were: 0.27 h [0.01;0.52], 0.34 [0.09;0.58] and 0.67 [0.44;0.90] at -12, -8 and -2 years, respectively. Bedtime trajectories showed an earlier bedtime in cases up to -8 years. CONCLUSION: long sleep duration and earlier bedtime may impact dementia incidence