Abstract
Evidence increasingly suggests that sleep disorders may be involved in the development of dementia. However, the results are very heterogeneous and gaps remain in the knowledge of the mechanisms involved in this association and the evolution of sleep in the neurodegenerative process. The main objective of this thesis is to study the role of sleep in dementia in the general population using an epidemiological approach. Data were drawn from the French 3-Cities cohort, composed of 9,294 subjects aged 65 years and over. We found that excessive daytime sleepiness and hypnotic consumption were associated with an increased risk of dementia, differentially according to the etiology of dementia (Study 1). We also observed a modest role of cardiovascular burden in the association between excessive daytime sleepiness and dementia, suggesting a complex relationship with possibly multiple mediating pathways (Study 2). Finally, modeling and comparing the evolution of several sleep parameters in the years preceding the diagnosis of dementia between future dementia cases and controls allowed us to highlight potential bidirectional relationships between the lengthening of sleep durations, time spent in bed, earliness of bedtime and dementia (Study 3). Together, these results reinforce previous studies and provide new evidence for the involvement of sleep in the development of dementia.