The role of depression and physical activity in the association of between sleep quality, and duration with and health-related quality of life among the elderly: a UK Biobank cross-sectional study.

BACKGROUND: Although studies have shown that sleep quality (duration) is associated with health-related quality of life (HRQoL), most of these studies have been small-sized and targeted at young and middle-aged adults. In addition, few studies have explored the path mechanism of sleep disorders leading to impaired HRQoL. OBJECTIVES: This study aimed to determine the association between sleep quality and duration and HRQoL among the elderly in the United Kingdom, assess whether depression mediated the association, and explore the role of physical activity (PA) in the path association. METHODS: Data were extracted from the baseline survey of the UK Biobank, a large prospective cohort study enrolling more than 500,000 participants, of which 52,551 older adults (aged ≥60 years) were included in the study. HRQoL was assessed using the European Quality of Life-5 Dimensions. Tobit and multivariate logistic regression models were used to determine the association between sleep quality and duration and HRQoL. The mediating and moderated mediation models were estimated using the PROCESS macro and MEDCURVE macro. RESULTS: The Tobit model showed that the elderly with short or long sleep duration (ß = - 0.062, 95% confidence interval [CI] = - 0.071 to - 0.053; ß = - 0.072, 95% CI = - 0.086 to - 0.058) had worse HRQoL after adjusting potential covariates. In the logistic regression models, we found an inverted U-shaped association between sleep duration and HRQoL. Moreover, a significant positive association was observed between sleep quality and HRQoL (all P < 0.05). The results also revealed that depression mediated the association between sleep disorders and HRQoL (sleep quality: ß = 0.008, 95% CI = 0.007-0.010; sleep duration: θ = 0.001 [mean], 95% CI = 0.001-0.002). Furthermore, PA moderated all paths among sleep quality and duration, depression, and HRQoL, and greater effects were observed in the elderly with lower PA levels. CONCLUSIONS: The findings show that poor sleep quality and duration were independently associated with worse HRQoL among the elderly in the United Kingdom. Furthermore, PA buffers the mediating effect of depression and adverse effects of sleep disorders on HRQoL. It is essential to properly increase PA and provide early intervention for depression in the elderly with sleep disorders to improve their HRQoL.

The Association of Optimism with Sleep Duration and Quality: Findings from the Coronary Artery Risk and Development in Young Adults (CARDIA) Study.

Optimism is associated with better health outcomes with hypothesized effects due in part to optimism's association with restorative health processes. Limited work has examined whether optimism is associated with better quality sleep, a major restorative process. We test the hypothesis that greater optimism is associated with more favorable sleep quality and duration. Main analyses included adults aged 32-51 who participated in the Coronary Artery Risk Development in Young Adults (CARDIA) study (n = 3,548) during the fifth (Year 15: 2000-2001) and sixth (Year 20: 2005-2006) follow-up visits. Optimism was assessed using the revised Life-Orientation Test. Self-report measures of sleep quality and duration were obtained twice 5 years apart. A subset of CARDIA participants (2003-2005) additionally provided actigraphic data and completed the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). Multivariate regression analyses were used to examine associations of optimism and sleep indicators. In cross-sectional analyses of 3548 participants, each standard deviation (SD) higher optimism score resulted in 78% higher odds of self-reporting very good sleep quality. Prospectively, a 1-SD higher optimism score was related to higher odds of reporting persistently good sleep quality across 5-years relative to those with persistently poor sleep [OR = 1.31; 95%CI:1.10,1.56]. In participant with supplementary data, each SD higher optimism score was marginally associated with 22% greater odds of favorable sleep quality [OR = 1.22; 95%CI:1.00,1.49] as measured by the PSQI, with possible mediation by depressive symptoms. Optimism was unrelated to objective actigraphic sleep data. Findings support a positive cross-sectional and prospective association between optimism and self-reported sleep behavior.