Sleep timing, sleep regularity, and psychological health in early late life women: Findings from the Study of Women's Health Across the Nation (SWAN)

Objectives: To examine the associations of actigraphy-assessed sleep timing and regularity with psychological health in early late life women, whose circadian rhythms may be impacted by aging. Design: Cross-sectional.Participants: A racially/ethnically diverse sample of 1197 community-dwelling women (mean age 65 years) enrolled in the Study of Women's Health Across the Nation. Measures: Actigraphy-assessed sleep measures included timing (mean midpoint from sleep onset to wake-up) and regularity (standard deviation of midpoint in hours). Psychological health measures included a com-posite well-being score, the Center for Epidemiological Studies Depression Scale, and the Generalized Anxi-ety Disorder-7 Scale. Linear and logistic regression models, adjusted for covariates (including sleep duration), tested associations between sleep and psychological health measures.Results: After covariate adjustment, a sleep midpoint outside of 2:00-4: 00 AM was significantly associated with depressive symptoms (fi = 0.88, 95% CI = 0.06, 1.70) and scoring above the cut-point for clinically signifi-cant depressive symptoms (OR = 1.72, 95% CI = 1.15, 2.57). Sleep irregularity was significantly associated with lower psychological well-being (fi =-0.18, 95% CI =-0.33,-0.03), depressive (fi = 1.36, 95% CI = 0.29, 2.44) and anxiety (fi = 0.93, 95% CI = 0.40, 1.46) symptoms, and scoring above the cut-point for clinically significant depressive (OR = 1.68, 95% CI = 1.01, 2.79) and anxiety (OR = 1.62, 95% CI = 1.07, 2.43) symptoms.Conclusion: Above and beyond sleep duration, a sleep midpoint outside of 2:00-4:00 AM was associated with depressive symptoms while sleep irregularity was associated with multiple psychological health domains in late life women. (c) 2022 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.