0680 Body Clock and Aging: Relationships of Circadian Rhythm with Sleep Quality, Mental Health and Geriatric Conditions

Abstract Introduction Circadian rhythm is associated with sleep quality and mental health. Research to date has been primarily focussed on adolescent and general adult populations, with little inquiry in older adults, whom have relatively earlier circadian phases. We sought to clarify correlates of circadian function with sleep quality and mental health, in addition to geriatric conditions to further explore these relationships in an older adult population. Methods We undertook a cross-sectional study of 67 community-dwelling older adults (≥60yrs) with self-reported sleep complaints. Circadian rhythm was assessed with 7-day actigraphy, to derive sleep midpoint and variables of circadian strength (interdaily stability (IS), intradaily variability (IV), amplitude, and MESOR), calculated using non-parametric or cosinor analysis. Assessments evaluated outcome measures of subjective sleep quality (Insomnia Severity Index [ISI], Pittsburgh Sleep Quality Index [PSQI], Epworth Sleepiness Scale [ESS]), objective sleep physiology (nocturnal polysomnography parameters), mental health (prior psychiatric diagnosis [depression, bipolar anxiety, PTSD], Patient Health Questionnaire of depressive symptoms [PHQ8], Generalized Anxiety Disorder Questionnaire [GAD2]), geriatric conditions (age, frailty [Fried phenotype], cognition with Montreal Cognitive Assessment [MOCA], falls (≥1 in past year), multimorbidity [≥3 chronic conditions], and polypharmacy [≥5 medications]). Pearson correlation coefficients were employed to investigate relationships. Results Circadian rhythm markers (lower amplitude, MESOR) were associated with daytime sleepiness (r=0.25-0.29, p values < 0.05). Later sleep midpoint was correlated with reduced total sleep time on PSG (r=0.36, p< 0.05), and lower ISI severity (r=0.29, p< 0.05). Measures of circadian weakness (lower IS, higher IV) were associated with mental health diagnoses (r=0.25-0.30; p values < 0.05), though no significant associations were seen with psychiatric symptoms. Earlier sleep midpoint was correlated with increasing age (r=0.41, p< 0.05). Parameters of circadian weakness (low IS, high IV, low amplitude) were associated with lower cognitive scores (r=0.32-0.44, p values < 0.05) and multimorbidity (r=0.30-0.36, p values < 0.05). Conclusion Our data strengthens links between circadian rhythm characteristics with sleep quality and mental health conditions, demonstrating generalizability to older adult populations. Markers of weaker circadian rhythm were associated with cognitive dysfunction and multimorbidity. Future research should examine the association of circadian markers with incident geriatric illness longitudinally. Support (if any) NIA (K76AG0749505, P30AG021342)