Sleep characteristics and cerebrospinal fluid biomarkers of Alzheimer's disease pathology in cognitively intact older adults: The CABLE study

INTRODUCTION: This study tested the self-reported sleep characteristics associated with cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarkers in cognitively intact older adults. METHODS: The linear and non-linear regression analyses were conducted in 736 cognitively normal participants (mean standard deviation; SD age, 62.3 10.5 years, range 40 to 88 years, 59% female) who had measurements of cerebrospinal fluid (CSF) amyloid beta (Aβ) and tTau proteins and sleep characteristics, after adjusting for age, gender, education, apolipoprotein E gene (APOE) ε4 status, and general cognition. RESULTS: Greater daytime sleepiness was associated with higher CSF indicators of amyloid deposition in female patients. No significant associations were revealed for CSF tTau proteins after Bonferroni correction. A U-shaped relationship was revealed for nocturnal sleep habits, such that those with insufficient or excessive nocturnal sleep duration had greater CSF biomarkers of amyloid deposition (the reflection range: bedtime: around 10:00 p.m. and sleep duration: 6.0 to 6.5 hours). DISCUSSION: These findings consolidated the close relationship between sleep and AD.