Search

This study aimed to investigate the association between bedtime and cardiac autonomic function in older adults. This cross-sectional study included community-dwelling older adults aged ≥ 65 years. Self-reported bedtime was categorized as early (< 21:30), intermediate (21:30–22:30), and late (> 22:30). Cardiac autonomic function was evaluated by HRV. The lowest tertiles for each HRV parameter were defined as unhealthy indicators. A total of 3,729 individuals participated, with mean age of 76.3 ± 6.6 years. After controlling for various covariates, late bedtime was associated with a lower risk for unhealthy total power [Odds ratio (OR) = 0.74; 95% confidence interval (CI) = 0.59–0.93] and low frequency power (OR = 0.69, 95% CI = 0.55–0.87) than intermediate bedtime. In contrast, early bedtime was correlated with a higher risk of poor total power (OR = 1.23, 95% CI: 1.05–1.45) and high frequency power (OR = 1.18, 95% CI = 1.00–1.39). When further specifying sleep duration and physical disability into the regression models, the inverse association between late bedtime and unhealthy HRV remained; however, the association between early bedtime and HRV disappeared. Accordingly, we concluded that in terms of cardiac autonomic function, early bedtime in older adults is not necessarily beneficial for their health outcomes, whereas late bedtime may not be detrimental. Abbreviations: ADL: activity of daily living; BMI: body mass index; CI: confidence interval; GARS: the Groningen Activity Restriction Scale; HADS: The Hospital Anxiety and Depression Scale; HF: high frequency power; HRV: heart rate variability; LF: low frequency power; LF/HF: low frequency to high frequency ratio; OR: odds ratios; TP: total power. [ABSTRACT FROM AUTHOR]

Objectives: Given the close relationship between sleep-wake disturbances and depression, an in-depth investigation of such a relationship is imperative. The present study aims at elucidating the relationship between various sleep-wake disturbances and depression in older adults and at examining the influence of co-occurring anxiety on such associations. Method: A community-based survey using the cohort from the Yilan Study in Taiwan was conducted from August 2013 to November 2016. Adults aged 65 and older were randomly selected to participate in the study. The Hospital Depression and Anxiety Scale was used to measure clinical depressive and anxiety symptoms. Insomnia and daytime sleepiness were defined through the Athens Insomnia Scale and the Epworth Sleepiness Scale, respectively. Furthermore, the use of hypnotics, subjective sleep duration and sleep-wake scheduling were evaluated. Their relationship with depression was examined through logistic regression analyses. Results: There were 2620 participants surveyed and 247 (9.4%) had depression. Before controlling for anxiety, insomnia (OR: 1.78, 95% CI: 1.23-2.55), daytime sleepiness (OR: 1.79, 95% CI: 1.27-2.53), and long sleepers (OR: 1.77, 95% CI: 1.24-2.53) have a higher likelihood for depression in the multivariable regression analysis. However, when including anxiety into the multivariable regression model, only those with daytime sleepiness and long sleepers had an elevated risk for depression. Therefore, the association between insomnia and depression turned to be statistically non-significant. Conclusion: In older adults, various sleep-wake disturbances differ in their relationship with depression. In addition, daytime sleepiness and long sleep duration were mostly characteristic of depression when co-occurring anxiety was considered. [ABSTRACT FROM AUTHOR]