Excessive sleep duration increases the risk of dementia among older Chinese adults: evidence from the CLHLS.

Cohort studies about the sleep duration on the risk of death among Chinese older adults are still lacking. The aim of this study was to examine whether extremely long or short sleep duration was associated with mortality in Chinese adults aged 65 years or older. We included participants aged 65 years or older in 2011 at baseline in 23 provinces from the Chinese Longitudinal Healthy Longevity Survey who were followed up in 2014/2018 in China. Sleep duration was categorized as short sleep duration (< 7 hours) and long sleep duration (> 8 hours). We used the Cox proportional hazards model and restricted cubic spline analysis to explore the association between sleep duration and mortality. Among 9578 participants, short sleep duration was associated with an 11% higher risk of death (adjusted hazard ratio [aHR]: 1.11; 95% confidence interval [CI]: 1.02-1.20) and long sleep duration was associated with a 24% higher risk of death (aHR: 1.24; 95% CI: 1.15-1.34), after adjustment for all covariates. There was a U-shaped association between sleep duration and all-cause mortality (nonlinear, P < .0001). Stratified analyses showed that the risk was higher among older people who smoked and with a higher level of education both for short and long sleepers than for those who never smoked and were illiterate (P value for interaction < .05). There was a U-shaped association between sleep duration and all-cause mortality in Chinese older adults, especially in more educated individuals and smokers. Du M, Liu M, Liu J. The association between sleep duration and the risk of mortality in the Chinese older adults: a national cohort study. J Clin Sleep Med. 2021;17(9):1821-1829.

As people age, declines in physiological functions can lead to changes in sleep and dietary patterns, potentially influencing cognitive function. However, longitudinal evidence examining how food consumption mediates the relationship between sleep parameters and cognitive function in Chinese older adults remains limited. Examining these longitudinal trajectories, beyond single-timepoint measurements, is crucial for understanding their dynamic nature and impact on cognitive function. Therefore, this study aimed to assess the longitudinal trajectories of sleep and food consumption in older adults, and to examine the mediating role of food consumption patterns in the sleep-cognition relationship. The sample population included 8724 older adults who derived from waves 4 to 7 (2005 to 2014) in the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Self-reported sleep duration, sleep quality, and food consumption were evaluated in face-to-face interviews. The main outcomes were global cognitive composite z scores. Group-based trajectory modeling (GBTM) identified distinct long-term change patterns of sleep duration, sleep quality and food consumption, and generalized estimating equations (GEE) evaluated their prospective associations with global cognitive scores. Additionally, structural equation modeling (SEM) was performed to assess the mediating role of food consumption in the relationships between sleep duration, sleep quality, and cognitive function. Food consumption mediated the associations between sleep duration, sleep quality, and cognitive function in older adults. After adjusting for confounders, decreasing low fruit and vegetable consumption mediated a negative impact on cognition, with both shortened (0.024, 95%CI: 0.003 to 0.048) and excessive sleep duration (0.076, 95%CI: 0.040 to 0.117) linked to decreasing low fruit and vegetable consumption. A rapid decline in meat, fish, egg, and bean consumption also mediated the negative effect of shorter sleep duration on cognition (mediation effects: -0.009, 95%CI: -0.014 to -0.005), whereas increased milk consumption acted as a complete mediator, positively influencing cognition. No mediating effect was observed for nuts consumption. Furthermore, stable, high-quality sleep promoted increased consumption of fruit and vegetable (0.039, 95%CI: 0.020 to 0.058), meat, fish, egg, and bean (-0.011, 95%CI: -0.133 to -0.088), milk (0.022, 95%CI: 0.001 to 0.043), and nuts (0.043, 95%CI: 0.021 to 0.065), all positively associated with cognitive levels. This study illustrates that food consumption can improve the decline in cognitive levels in older adults that may be undermined by unhealthy sleep habits. Our research findings are of great importance to both clinical practice and public health policy.

BackgroundThe impact of sleep duration on cognition, particularly in the context of poststroke cognitive impairment, is not fully understood. Therefore, our objective was to investigate how sleep duration after stroke predicts poststroke cognitive impairment.Methods and ResultsPatients admitted with acute stroke between 2015 and 2017 were consecutively recruited to the Nor‐COAST (Norwegian Cognitive Impairment After Stroke) study and invited to follow‐up assessments at 3 and 18 months. Time in bed, used as a surrogate for sleep duration at 3 months post stroke, was measured using the activPAL thigh‐worn sensor over a 3‐day period. Sleep duration was categorized into 3 groups: <7 hours (insufficient), 7 to 9 hours (reference), and ≥9 hours (excessive). Cognitive impairment was assessed based on the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) criteria at 3‐ and 18‐month follow‐up. Out of the 815 patients, we included 443 (54%) prestroke cognitive healthy with valid activPAL registration in this analysis. Mean±SD age was 71.2±11.4 years, 185 (42%) were women, 363 (82%) had prestroke modified Rankin Scale score <2, and 345 (78%) suffered a minor stroke (National Institutes of Health Stroke Scale score ≤5). On average, participants spent 8.3±1.4 hours in bed each night, 17.2% had a sleep duration <7 hours, and 25% slept more than 9 hours. Insufficient (odds ratio [OR], 3.6 [95% CI, 1.3–10.2], and OR, 1.4 [95% CI, 0.5–3.8]) and excessive (OR, 2.8 [95% CI, 1.1–7.5], and OR, 3.3 [95% CI, 1.3–8.1]) sleep duration were associated with an increased risk of cognitive impairment at 3‐ and 18‐month follow‐up, respectively.ConclusionsInsufficient or excessive sleep duration was associated with poststroke cognitive impairment.

BackgroundThe association of sleep onset time and duration with cardiometabolic health is not well characterized.Methods and ResultsThis study included 6696 adults aged 20 to 80 years from the NHANES (National Health and Nutrition Examination Study) 2015 to 2018. Participants were categorized into 9 groups according to the cross‐tabulation of sleep onset time (<22:00 [early], 22:00–23:59 [optimal], and ≥24:00 [late]) and duration (<7 hours [insufficient], 7–8 hours [sufficient], and ≥9 hours [excessive]), with optimal sleep onset time and sufficient duration as the reference. The primary outcomes included hypertension, hypertriglyceridemia, low high‐density lipoprotein cholesterol, hyperglycemia, central obesity, and metabolic syndrome. Inappropriate sleep onset time and sleep duration were associated with increased odds of hypertension, hypertriglyceridemia, and metabolic syndrome, especially among participants aged 40 to 59 years. Compared with men reporting optimal onset and sufficient duration, men reporting optimal onset with excessive duration (odds ratio [OR]: 2.01 [95% CI, 1.12–3.58]) and late onset with insufficient duration (OR, 1.74 [95% CI, 1.13–2.68]) had higher odds of metabolic syndrome. Compared with women reporting optimal onset and sufficient duration, women reporting optimal onset and insufficient duration (OR, 1.61 [95% CI, 1.11–2.32]) and early onset and excessive duration (OR, 2.16 [95% CI, 1.30–3.57]) had higher odds of hypertension, and women reporting late onset and excessive duration (OR, 5.64 [95% CI, 1.28–6.77]) were at the highest odds of hypertriglyceridemia.ConclusionsLate sleep onset as well as insufficient or excessive sleep duration are associated with adverse cardiometabolic outcomes, particularly in participants aged 40 to 59 years.

Associations of prediabetes and sleep duration, and inflammation as a mediator in the China Health and Retirement Longitudinal Study

This study examined the relationship between sleep disorders and the risk of dementia in patients with newly diagnosed type 2 diabetes. This study used the Korean Health Screening Cohort data and included 39 135 subjects aged ≥40 years with new-onset type 2 diabetes between 2004 and 2007, with follow-up throughout 2013. Sleep disorders were measured by F51(sleep disorders not due to a substance or known physiological condition) or G47(sleep disorders) under International Classification of Diseases, Tenth Revision (ICD-10) codes as a primary diagnosis, and the adjusted hazard ratio (AHR) and 95% CI of all-cause dementia, Alzheimer disease, vascular dementia, and other dementia were estimated using multivariable Cox proportional hazards regression models. In the patients with type 2 diabetes with an age range between 42 and 84 years (M = 57.8, SD = 9.5), this study identified 2059 events of dementia during an average follow-up time of 5.7 years. In patients with type 2 diabetes, subjects with sleep disorders were associated with an increased risk of all-cause dementia (AHR, 1.46; 95% CI, 1.19-1.80), Alzheimer disease (AHR, 1.39; 95% CI, 1.02-1.88), and other dementia (AHR, 1.69; 95% CI, 1.23-2.31) compared to those without sleep disorders. Men (AHR, 1.93; 95% CI, 1.42-2.62) and older adults (AHR, 1.70; 95% CI, 1.35-2.15) with sleep disorders were associated with an increased risk of dementia than their counterparts without sleep disorders among patients with type 2 diabetes. These findings suggest that sleep disorders are significantly associated with an increased risk of dementia in patients with new-onset type 2 diabetes.

Objectives: Good maternal health and fetal development require sufficient and good quality of sleep during pregnancy. This study investigated sleep duration and quality in pregnant women, assessing factors with possibly influence on sleep. Method: A cross-sectional survey was conducted on pregnant women between June and August in 2015 in 16 hospitals in five provinces in China. A total of 2345 pregnant women aged 18 years and older were surveyed. Insufficient sleeping duration was defined as sleeping of less than 7 h per day. Excessive sleep duration was defined as sleeping of more than 9 h per day. Results: A total of 561 (23.9%) participants reported insufficient sleeping duration, whereas 485 (20.9%) claimed excessive sleep duration. A total of 358 (15.2%) of pregnant women reported problems regarding sleep quality. Compared to pregnant women with sufficient sleeping duration, those with insufficient sleeping duration were prone to have poor sleep quality, whereas those with excessive sleeping duration featured low possibility of poor sleep quality. High-risk groups of insufficient sleep duration include women of Han nationality, with siblings, in their first trimester of pregnancy, receiving care in low-capacity/quality hospital settings, and with daily or 1–3 days of secondhand smoke exposure. High-risk groups of excessive sleep duration include women living in rural areas, unemployed, in their third trimester of pregnancy, and receiving care in medium-capacity/quality hospital settings. High-risk groups of poor sleep quality include women of non-Han nationality, low income level, in their third trimester of pregnancy, and with insufficient sleep duration. Conclusions: Insufficient/excessive sleep duration and poor sleep quality commonly occur during pregnancy in China. Findings provide a better understanding of the influencing factors of insufficient/excessive sleep duration and poor quality of sleep. These findings have some implications for future interventions on sleep among pregnant women.

BackgroundDisturbed sleep patterns are common among older adults and may contribute to cognitive and physical declines. However, evidence for the relationship between sleep duration and cognitive frailty, a concept combining physical frailty and cognitive impairment in older adults, is lacking.ObjectiveThis study aimed to examine the associations of sleep duration and its changes with cognitive frailty.MethodsWe analyzed data from the 2008‐2018 waves of the Chinese Longitudinal Healthy Longevity Survey. Cognitive frailty was rendered based on the modified Fried frailty phenotype and Mini-Mental State Examination. Sleep duration was categorized as short (<6 h), moderate (6‐9 h), and long (>9 h). We examined the association of sleep duration with cognitive frailty status at baseline using logistic regressions and with the future incidence of cognitive frailty using Cox proportional hazards models. Restricted cubic splines were used to explore potential nonlinear associations.ResultsAmong 11,303 participants, 1298 (11.5%) had cognitive frailty at baseline. Compared to participants who had moderate sleep duration, the odds of having cognitive frailty were higher in those with long sleep duration (odds ratio 1.71, 95% CI 1.48‐1.97; P<.001). A J-shaped association between sleep duration and cognitive frailty was also observed (P<.001). Additionally, during a mean follow-up of 6.7 (SD 2.6) years among 5201 participants who were not cognitively frail at baseline, 521 (10%) participants developed cognitive frailty. A higher risk of cognitive frailty was observed in participants with long sleep duration (hazard ratio 1.32, 95% CI 1.07‐1.62; P=.008).ConclusionsLong sleep duration was associated with cognitive frailly in older Chinese adults. These findings provide insights into the relationship between sleep duration and cognitive frailty, with potential implications for public health policies and clinical practice.

Sleep duration, psychiatric disorders and dementias are closely interconnected in older adults. However, the underlying genetic mechanisms and brain structural changes are unknown. Using data from the UK Biobank for participants primarily of European ancestry aged 38-73 years, including 94% white people, we identified a nonlinear association between sleep, with approximately 7 h as the optimal sleep duration, and genetic and cognitive factors, brain structure, and mental health as key measures. The brain regions most significantly underlying this interconnection included the precentral cortex, the lateral orbitofrontal cortex and the hippocampus. Longitudinal analysis revealed that both insufficient and excessive sleep duration were significantly associated with a decline in cognition on follow up. Furthermore, mediation analysis and structural equation modeling identified a unified model incorporating polygenic risk score (PRS), sleep, brain structure, cognition and mental health. This indicates that possible genetic mechanisms and brain structural changes may underlie the nonlinear relationship between sleep duration and cognition and mental health.

Poor sleep status as a common concern is a risk factor for many health problems among older people. China with an aging society lacks relevant nationwide data on the sleep status among older people. Therefore, the purpose of this study was to investigate trends and disparities in sleep quality and duration among older adults, and exploring influencing factors of poor sleep in China between 2008 and 2018. We used the four-waves data of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) from 2008 to 2018. Sleep quality and average sleep hours per day was investigated by using questionnaires in the CLHLS. We categorized sleep duration as three groups including ≤5 h (short duration), 5-9 h (normal duration), or ≥9 h (long duration) per day. Multivariate logistic regression models were used to examine trends and risk factors of poor sleep quality, short sleep duration, and long sleep duration. The prevalence of poor sleep quality significantly increased from 34.87% in 2008 to 47.67% in 2018 (p < 0.05). Short sleep duration significantly increased from 5.29 to 8.37%, whereas long sleep duration decreased from 28.77 to 19.27%. Multivariate analysis showed that female sex, poor economic status, a greater number of chronic diseases, underweight, poor self-reported quality of life, and poor self-reported health were associated with poor sleep quality and short sleep duration (p < 0.05). Our findings revealed that older adults had increased prevalence of poor sleep quality and short sleep duration from 2008 to 2018. More attention should be paid to the increased sleep problems among older adults and early interventions should be made to improve sleep quality and guarantee enough sleep time.

Association between sleep pattern and incidence of hypertension: A prospective cohort study of older adult participants in the Chinese longitudinal healthy longevity survey

BackgroundSleep dysregulation is a feature of dementia but whether sleep duration prior to old age is also associated with incidence of dementia remains unclear. We examined the association of sleep duration in midlife with risk of late‐life dementia.MethodData were drawn from 7959 participants (women=33.0%) of the Whitehall II cohort study, established in 1985‐1988, from which self‐reported sleep duration at age 50, 60, and 70 was extracted and categorized as “short: ≤6 hours per night”, “normal: 7 hours per night”, “long: ≥8 hours per night”. Incident dementia (N=521) cases were identified through electronic health registers until March 2019.ResultCompared to normal sleep duration, higher risk of incident dementia was observed among those with short sleep duration at ages 50 and 60 (mean follow‐up 25 and 15 years, respectively), although not significantly at age 70 (hazard ratio 1.22 (95% confidence interval 1.01‐1.48), 1.37 (1.10‐1.72), and 1.24 (0.98‐1.57), respectively). Persistent short sleep duration at age 50, 60, and 70 compared to persistent normal sleep duration was also associated with a 32% (hazard ratio 1.32 (1.02‐1.72)) increased risk of dementia independently of sociodemographic, behavioural, cardiometabolic, and mental health factors. These associations were also evidence when analyses were restricted to participants without a history of mental illness before age 65 years. In a subsample with objective measure of sleep (accelerometer data, N=3888), the association of short sleep duration with increased risk of dementia was confirmed.ConclusionThis study paying attention to both age at sleep duration and length of follow‐up along with inclusion of a wide array of covariates shows that short sleep duration in midlife is associated with an increased risk of dementia. Public health messages to encourage good sleep hygiene, may be particularly important for people at higher risk of dementia.

STUDY QUESTIONAre there associations between natural or surgical menopause and incident dementia by age at menopause?SUMMARY ANSWERCompared to age at menopause of 46–50 years, earlier natural menopause (≤40 and 41–45 years) was related to higher risk of all-cause dementia, while a U-shape relationship was observed between age at surgical menopause and risk of dementia.WHAT IS KNOWN ALREADYMenopause marks the end of female reproductive period. Age at menopause reflects the length of exposure to endogenous estrogen. Evidence on the association between age at natural, surgical menopause, and risk of dementia has been inconsistent.STUDY DESIGN, SIZE, DURATIONA population-based cohort study involving 160 080 women who participated in the UK Biobank study.PARTICIPANTS/MATERIALS, SETTING, METHODSWomen with no dementia at baseline, and had no missing data on key exposure variables and covariates were included. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs on the association of categorical menopause age with incident all-cause dementia, Alzheimer’s disease (AD) and vascular dementia (VD). Restricted cubic splines were used to model the non-linear relationship between continuous age at natural, surgical menopause, and risk of dementia. In addition, we analyzed the interaction effect of ever-used menopausal hormone therapy (MHT) at baseline, income level, leisure activities, and age at menopause on risk of dementia.MAIN RESULTS AND THE ROLE OF CHANCECompared to women with age at menopause of 46–50 years, women with earlier natural menopause younger than 40 years (1.36, 1.01–1.83) and 41–45 years (1.19, 1.03–1.39) had a higher risk of all-cause dementia, while late natural menopause >55 years was linked to lower risk of dementia (0.83, 0.71–0.98). Compared to natural menopause, surgical menopause was associated with 10% higher risk of dementia (1.10, 0.98–1.24). A U-shape relationship was observed between surgical menopause and risk of dementia. Women with surgical menopause before age 40 years (1.94, 1.38–2.73) and after age 55 years (1.65, 1.21–2.24) were both linked to increased risk of all-cause dementia. Women with early natural menopause without ever taking MHT at baseline had an increased risk of AD. Also, in each categorized age at the menopause level, higher income level or higher number of leisure activities was linked to a lowers risk of dementia.LIMITATIONS, REASONS FOR CAUTIONMenopausal age was based on women’s self-report, which might cause recall bias.WIDER IMPLICATION OF THE FINDINGSWomen who experienced natural menopause or had surgical menopause at an earlier age need close monitoring and engagement for preventive health measures to delay the development of dementia.STUDY FUNDING/COMPETING INTERESTSThis work was supported by the Start-up Foundation for Scientific Research in Shandong University (202099000066), Science Fund Program for Excellent Young Scholars of Shandong Provence (Overseas) (2022HWYQ-030), and the National Natural Science Foundation of China (82273702). There are no competing interests.TRIAL REGISTRATION NUMBERN/A.

Whether sleep quality and duration assessed from multiple domains, either individually or in combination, are strongly associated with mortality risk in older adults remains unelucidated. We aimed to clarify these relationships. We enrolled 7,668 older (age ≥65 years) Japanese adults in the Kyoto-Kameoka prospective cohort study who provided valid responses to the Pittsburgh Sleep Quality Index (PSQI) in a mail-in survey. Sleep quality and duration were classified into six groups using the previously validated PSQI: short sleep duration (SSD: <360 min/day)/sleep disturbance (SD: ≥5.5 PSQI points), n = 701; SSD/non-sleep disturbance (NSD: <5.5 PSQI points), n = 100; optimal sleep duration (OSD: 360-480 min/day)/NSD, n = 1,863; OSD/SD, n = 2,113; long sleep duration (LSD: >480 min/day)/NSD, n = 1,972; LSD/SD, n = 919. Mortality data were collected from February 15, 2012, to November 30, 2016. We evaluated the relationship between all-cause mortality risk and sleep quality and duration (and their combinations) using a multivariable Cox proportional hazards model that included baseline covariates. The median follow-up period was 4.75 years (34,826 person-years), with a total of 616 deaths. After adjusting for confounders, compared with other groups, SSD/SD and LSD/SD had the highest hazard ratio (HR) of mortality (SSD/SD: HR 1.56; 95% confidence interval [CI], 1.10-2.19; SSD/NSD: HR 1.27; 95% CI, 0.47-3.48; OSD/NSD: reference; OSD/SD: HR 1.20; 95% CI, 0.91-1.59; LSD/NSD: HR 1.35; 95% CI, 1.03-1.77; LSD/SD: HR 1.83; 95% CI, 1.37-2.45). However, mortality risk was not associated with the interaction between sleep quality and duration. Older adults with sleep disturbances involving SSD and LSD have a strong positive association with mortality risk, suggesting an additive effect between sleep quality and duration.

ObjectivesInsufficient or excessive sleep and dyslipidemia are significant cardiovascular risk factors. Whilst the relationship between sleep duration and traditional lipid indices are well described, the connection to novel lipid and anthropometric indices remains unclear. This study examines these associations using National Health and Nutrition Examination Survey (NHANES) data from 2005 to 2020.MethodsThis cross-sectional study analyzed data from 9847 adults from NHANES 2005–2020, excluding those with major cardiovascular disease and cancer. Sleep duration was categorized as insufficient (< 7 h), normal (7-8 h), and excessive (> 8 h). Self-reported sleep disturbance was documented. Novel indices included non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR), Triglyceride to HDL-Cholesterol (TG/HDL), Triglyceride-Glucose (TyG) Index, Visceral Adiposity Index (VAI), Lipid Accumulation Product (LAP), Conicity Index (CI), Body-Roundness Index (BRI), A Body Shape Index (ABSI), and Weight-adjusted waist index (WWI). Generalized additive models (GAMs) with spline smoothing and threshold analysis assessed nonlinear associations, adjusting for confounders. Weighted multivariate linear regression evaluated linear associations.ResultsInsufficient sleep was associated with higher TyG combined with waist-to-height ratio (TyG–WHtR) (p = 0.003). Excessive sleep was linked to higher TyG–WHtR, CI, BRI, ABSI, and WWI (p < 0.001). Sleep disturbance was associated with elevated TyG–WHtR, TyG–WC, LAP, CI, BRI, ABSI, and WWI (p < 0.001). Threshold analysis confirmed significant changes in several indices, emphasizing the impact of both insufficient and excessive sleep.ConclusionsInsufficient, excessive sleep duration and sleep disturbance are associated with adverse lipid and anthropometric profiles, indicating increased cardiometabolic risk. Optimal sleep duration and addressing sleep disturbance could mitigate these risks. Further research is needed to understand the underlying mechanisms.