Mediating role of depressive symptoms on the relationship between sleep duration and cognitive function

Longitudinal patterns of cognitive function and depression: insights from the China Health and Retirement Longitudinal Study

Background

With the acceleration of population aging, cognitive impairment and depression have become serious public health challenges in countries around the world. The influencing factors of cognitive trajectory, depression trajectory, and dual trajectories in middle-aged and elderly adults have not been fully studied.

Methods

This study used data from the China Health and Retirement Longitudinal Study database spanning from 2011-2018. Group-based trajectory modelling and group-based dual trajectory modelling were employed to examine different trajectories. Restricted cubic spline and multivariate logistic regression analysis were used to elucidate the relationship between sleep duration and grip strength with these different trajectories. Mediation analysis was conducted to explore the mediating roles of sleep duration and grip strength in the activities of daily living (ADLs) and their impact on these trajectories.

Results

Trajectory analysis identified two longitudinal patterns of cognitive function and depression scores: low and high cognitive group, low and high depression group, respectively, and two states of the dual trajectories of cognition and depression: the stable state group and the state decline group. Sleep duration and grip strength were associated with the cognitive trajectory, depression trajectory and dual trajectories. Sleep duration has an inverted U-shaped relationship with cognitive trajectory. Grip strength was nonlinearly associated with the above trajectories. The mediation effects of sleep duration in the association between ADLs and cognitive, depression and dual trajectories were 3.14, 6.14, and 2.70%. While the mediation effects of grip strength were 7.21, 1.67 and 6.24%, respectively (P < 0.05).

Conclusions

Sleep duration and grip strength were not only associated with cognitive, depression, and dual trajectories, but also partially mediate the relationship between ADLs and these trajectories. This study will provide a basis for how to intervene in the cognitive and mental health of middle-aged and elderly adults.

Long Sleep Duration, Cognitive Performance, and the Moderating Role of Depression: A Cross-Sectional Analysis in the Framingham Heart Study

INTRODUCTION

We investigated whether depression modified the associations between sleep duration and cognitive performance.

METHODS

Multivariable linear regression models examined the associations between sleep duration and cognition in 1,853 dementia- and stroke-free participants from the Framingham Heart Study. Participants were categorized in four groups: no depressive symptoms, no antidepressants; depressive symptoms without antidepressants use; antidepressant use without depressive symptoms; both depressive symptoms and antidepressant use.

RESULTS

Long sleep was associated with reduced overall cognitive function. Strong associations between sleep duration and cognitive performance were found in individuals with depressive symptoms, regardless of antidepressant use. Weaker but significant effects were observed in those without depressive symptoms. No significant associations were observed in participants using antidepressants without depressive symptoms.

DISCUSSION

These findings provide new evidence that sleep duration may be a modifiable risk factor for cognitive decline, particularly in individuals with depressive symptoms. Future research should elucidate underlying mechanisms and temporal relationships.

Associations between sleep duration, depression status, and cognitive function among Chinese elderly: A community-based study

BACKGROUND

The associations of sleep duration and depressive status on cognitive function among the elderly remain controversial. This study aimed to investigate the associative effects and mediating mechanisms between sleep duration and depressive status on cognitive function in elderly adults.

METHODS

Participants were recruited from cross-sectional and cohort surveys of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). We identified thresholds for sleep duration and depression and used logistic regression to explore their independent and joint effects on cognitive impairment. Further, we analyze the mediating effects of depressive status on the association between sleep duration and cognitive function.

RESULTS

Of 13840 elderly (median age: 84 years, female: 54.6 %), 2835 (20.5 %) had cognitive impairment. Compared with those who slept 6-8 h, the ORs (95%CIs) for those who slept < 6 h and > 8 h were 0.98 (0.85, 1.12) and 1.48 (1.32, 1.66). Compared with non-depressed, the OR (95%CI) for the depressed participants was 1.74 (1.53, 1.98). Compared with those with sleep 6-8 h and none-depression, those with sleep > 8 h and depression had the highest odds of cognitive impairment (OR = 2.40, 95%CI: 1.88-3.07). Additionally, Compared with those who slept 6-8 h, the associations between depression-mediated short and long sleep and cognitive impairment were 51.1 % and 6.5 %, respectively.

LIMITATIONS

Cross-sectional studies require caution in the interpretation of causal associations.

CONCLUSIONS

Long sleep and depression were independently and jointly associated with higher odds of cognitive impairment among the Chinese elderly, and short sleep increased the risk of cognitive impairment by promoting the prevalence of depression.

Long and short sleep durations can affect cognitive function in older adults through the chain mediation effect of ADL and depression: evidence from CHARLS2018

BACKGROUND

Both long and short sleep durations may lead to cognitive decline in the elderly individuals, though the underlying mechanisms remain unclear.

AIMS

To explore the mediating mechanism of activities of daily living and depression on different sleep durations and cognitive function in older Chinese older adults.

METHODS

This retrospective study used data from 5,899 older adults who completed the 2018 China Health and Retirement Longitudinal Surveys. We used the PROCESS macro in SPSS to determine the chain mediating effect of ADL and depression on the relationship between different sleep durations and cognitive functions.

RESULTS

(1) There were significant correlations among sleep duration, ability to perform ADL, depression, and cognitive function. (2) For sleep durations ≤ 7 h/night or > 7 h/night, ADL and depression play a chain mediating role in the relationship between sleep duration and cognitive function.

CONCLUSIONS

Shorter or longer sleep durations were associated with cognitive decline by weakening ADL and worsening depression, which suggests that medical personnel should take action to correct abnormal sleep duration in older adults. Timely treatment of ADL impairment and depression may help prevent cognitive decline.

Mediation analysis of cognitive function in the relationship between pulmonary function and depression among middle-aged and older adults

AIM

This study aims to explore the association between declining lung function and depression in middle-aged and older adults, with a special focus on the mediating role of cognitive function.

METHODS

This study utilizes self-reported and physical examination data from 5345 individuals participating in the 2015 cycle of the China Health and Retirement Longitudinal Study (CHARLS) to explore the role of cognitive function changes in mediating the effects of diminished lung function on depression among middle-aged and older adults.

RESULTS

Multivariate linear regression analysis revealed a positive correlation between pulmonary and cognitive functions (β = 0.003, 95% CI: 0.002∼0.003, P < 0.01) and a negative correlation between cognitive function and depression (β = -0.279, 95% CI: -0.330-0.228, P < 0.01). Cognitive function plays a mediating role in linking pulmonary function with depression, exhibiting a mediation effect of -0.0007 and a total effect of -0.0046, wherein the mediation effect contributes to 15.22% of the total effect. For females, the mediating effect of cognitive function was stronger (β = -0.0013, 95% CI: -0.0018∼-0.0008, P < 0.01) than it was for males (β = -0.0006, 95% CI: -0.0009∼-0.0003, P < 0.01).

CONCLUSIONS

The study underscores the importance of monitoring lung and cognitive functions as interconnected factors contributing to the mental health of middle-aged and older adults. It suggests that interventions aimed at improving pulmonary health and cognitive function may help mitigate depressive symptoms among middle-aged and older adults. Further research is warranted to validate these findings across diverse cultural and demographic settings. Geriatr Gerontol Int 2024; 24: 1210-1217.

Nonlinear association between self-reported sleep duration and cognitive function among middle-aged and older adults in China: The moderating effect of informal care

BACKGROUND

Cognitive impairment is a major public health problem urgently to be solved. This study aims to examine the association between sleep duration and cognitive function and its two subdimensions: episodic memory and mental status, and to explore the moderating effects of informal care on these associations among middle-aged and older adults in China.

METHODS

Data was drawn from China Health and Retirement Longitudinal Study (CHARLS) 2011, 2013, 2015 and 2018 datasets. Sleep duration and informal care were self-reported. Cognitive function was measured using CHARLS Harmonized Cognitive Assessment Protocol. Effects of informal care on sleep duration-cognitive function were assessed using Generalized Estimating Equations models.

RESULTS

The relationships between sleep duration and cognitive function, episodic memory, and mental status were all found to follow an inverted U-shaped pattern. Spouse care weakened the adverse effects of extreme sleep duration on cognitive function while the children care amplified them. Further, we only observed the moderating effects of spouse and children care on the association between sleep duration and episodic memory, but not mental status.

CONCLUSIONS

The relationships between sleep duration and cognitive function, along with its different dimensions, are nonlinear in nature. The impacts of sleep duration on cognitive function and its dimensions are contingent upon the levels of informal care received and the sources of that care. We provide valuable insights into the complex interplay between sleep duration, informal care, and cognitive function.