LAUSR

Sleep disruption is common in older adults with multiple chronic conditions and can occur before the clinical onset of Alzheimer’s disease (AD). Sleep disruption plays an important role in AD pathology and has been associated with neuro-imaging evidence of AD, and cerebrospinal fluid elevations of amyloid, tau, and neurodegeneration (ATN) biomarkers. Plasma ATN biomarkers are increasingly used in AD research. We examined the associations of self-reported sleep quality and electroencephalogram (EEG) sleep architecture with plasma ATN biomarkers in sedentary older adults without dementia. We used baseline data from an ongoing randomized controlled trial that examines the effect of physical activity on sleep and cognition in community-dwelling sedentary older adults without dementia (Montreal Cognitive Assessment [MoCA]>17, n=102). Participants reported demographics, completed the Pittsburgh Sleep Quality Index (PSQI) questionnaire, and provided blood samples to measure plasma ATN biomarkers [amyloid-beta (Aβ)42/42, total-tau (T-tau), and neurofilament light (NFL)]. Two-night home-based sleep EEG measures (Sleep Profiler) were collected from 56 of the 102 participants. Multiple regression models were conducted to test the associations between sleep measures and plasma ATN biomarkers. Participants were aged 69.9 ± 6.0 years, 80% were women, and they had 3.1±1.7 chronic conditions. Most had intact cognitive function (68.6% MoCA≥ 26) and 28.6% of the sample had mild cognitive impairment (17< MoCA< 25). In models adjusted for age, sex, race, education, and number of comorbidities, higher PSQI scores (β=0.84, 95% confident interval (CI)= [0.12,1.62]), longer non-rapid eye movement (NREM) N3 duration (β=4.43, 95% CI= [0.48,8.18]), and higher REM latency (β=0.04, 95% CI= [0.02, 0.05]) were associated with higher NFL. Longer REM sleep duration (β=-11.13, 95% CI= [-20.55, -1.71]) was associated with lower NFL. There were no other significant associations of sleep measures with other ATN biomarkers. Self-reported sleep quality and sleep architecture were associated with plasma NFL among older adults with intact cognition and mild cognitive impairment. Plasma NFL may be a sensitive and promising biomarker that links sleep disruption and AD-related outcomes in older adults without dementia. Future research with a larger sample is needed to further test this association. National Institute of Nursing Research R00NR016484