Sleep duration and metabolic syndrome: An updated systematic review and meta-analysis

Associations between sleep duration trajectories and risk of cardio-metabolic disease among middle-aged and older Chinese adults

BACKGROUND

The association of a single time-point measure of sleep duration with cardio-metabolic disease has been extensively studied, but few studies have focused on the impact of sleep duration trajectory. This study aims to model the sleep duration trajectory as predictors for the subsequent development of cardio-metabolic disease.

METHODS

This study recruited a notably large population (n = 9883) of subjects aged at least 45 years from the China Health and Retirement Longitudinal Study (CHARLS), who participated in sequential surveys conducted in 2011, 2013, 2015, and 2018. Sleep duration trajectories were plotted using data of night sleep duration recorded at intervals from 2011 to 2015 by latent class trajectory model. The onset of cardio-metabolic diseases from 2015 to 2018 were confirmed and then the risk of different sleep duration trajectories on incident cardio-metabolic disease was examined using cox proportional hazards regression model.

RESULTS

We identified four sleep duration trajectories. Compared to the normal-stable trajectory, the short-stable trajectory was significantly associated with higher risk of incident stroke (hazard ratio [HR], 1.32; 95 % confidence interval [CI], 1.02 to 1.70), dyslipidemia (HR, 1.22; 95%CI, 1.01 to 1.49), and diabetes (HR, 1.42; 95%CI, 1.13 to 1.78) within three years of follow-up, and the short-increasing trajectory predicted a higher risk of incident stroke (HR, 2.38; 95%CI, 1.25 to 4.55).

CONCLUSIONS

Short sleep trajectory could increase the risk of incident stroke, dyslipidemia, and diabetes, and an increasing sleep trajectory was associated with increased risk of incident stroke among middle-aged and older Chinese adults.

The Global Prevalence of Metabolic Syndrome in Connection with Sleep Duration: A Systematic Review and Meta-Analysis

The duration and quality of sleep are believed to significantly influence the onset of metabolic syndrome (MetS), but existing data lack consistency. The meta-analysis aims to evaluate the prevalence of the MetS in association with sleep duration. We conducted a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses 2020 guidelines. A comprehensive search of PubMed, Google Scholar, and Research Gate databases was performed to identify cohort and cross-sectional studies published in English between 2013 and 2023. We included studies that examined the association between sleep duration/quality and MetS, and two independent reviewers assessed study quality and bias using the Newcastle-Ottawa scale. The systematic review included 11 studies with a total of 343,669 participants, including 4 cohort studies and 7 cross-sectional studies. Sample sizes varied widely, ranging from 293 to 162,121 individuals. The studies had different follow-up periods, participant ages ranging from 10 to 80 years, and predominantly male populations. The prevalence of MetS was higher in average sleepers [52%, 95% confidence interval (CI): 40%-64%] compared with short sleepers (13%, 95% CI: 8%-18%) and long sleepers (15%, 95% CI: 9%-24%). Globally, North American countries exhibit the highest prevalence of MetS across short- (25.3%, 95% CI: 4.2%-72.4%) and long-sleeper (22.4%, 95% CI: 2.8%-74.1%) categories, whereas Asian countries experience the highest prevalence among the average sleeper category (58.7%, 95% CI: 44.1%-71.9%). Our meta-analysis indicates an elevated prevalence of MetS in average sleepers. Future research endeavors address delve into the underlying mechanisms and incorporate objective measures to understand the multifaceted connection between sleep patterns and MetS, guiding more effective preventive and management strategies.

Gut microbiome and metabolic pathways linked to sleep quality

Sleep quality is a vital determinant of human health as sleep disorders are associated with cognitive deficits, and chronic sleep deprivation is associated with a broad range of health complications. Previous studies on the association between the gut microbiome and sleep quality have been constrained by small sample sizes or have focused on specific sleep disorders, thus yielding inconsistent results. Herein, we investigated the relationship between microbial composition and sleep quality in a cohort of 159 Koreans. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI), determined through a self-administered questionnaire. Gut microbiome analyses were performed using 16S rRNA amplicons. We found no direct correlation between microbial alpha diversity metrics and sleep; however, we identified differences in beta diversity among sleep quality groups (with a PSQI score > 5 indicating poor sleep quality and PSQI ≤5 indicating good sleep quality). We also found differential microbial signatures (Bacteroides, Prevotella 9, and Faecalibacterium) among the groups. Furthermore, functional metabolic pathway profiles revealed significant linear correlations of the L-arginine and L-tryptophan biosynthetic pathways as well as 4-aminobutanoate degradation with sleep status. In particular, Faecalibacterium prausnitzii, which harbors these metabolic pathways, showed differences between sleep quality groups and a linear association with sleep quality scores and was thus identified as the species most strongly associated with sleep status. This study provides a significant advance in our understanding of the relationship between gut microbiota and sleep regulation. The current findings provide a basis for further research into potential therapeutic strategies for sleep disorders targeting the gut microbiome.

Joint association of sleep quality and physical activity with metabolic dysfunction-associated fatty liver disease: a population-based cross-sectional study in Western China

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a growing threat leading to substantial disease burden globally. Poor sleep and physical inactivity are common in modern societies and independently associated with MAFLD, however, their joint effects on MAFLD remains unclear.

METHODS

This population-based cross-sectional study was conducted in Xinjiang Uygur Autonomous Region, China, between July 2019 and September 2021. Self-reported sleep behaviors and physical activity (PA) were assessed using validated questionnaires. The primary outcome was radiological diagnosis of MAFLD.

RESULTS

Of the 10 089 participants aged 47.0 (9.1) years (51.6% men), 3854 (38.2%) individuals had MAFLD. Poor sleep quality and physical inactivity were independently and jointly associated with an increased prevalence of MAFLD, independent of traditional risk factors (P < 0.05). Compared to subjects with guideline-recommended moderate-to-vigorous PA (MVPA) and good sleep quality, individuals with no recommended MVPA and poor sleep had the highest possibility of MAFLD (odds ratio = 2.36, 95% confidence interval: 1.81 - 3.08). Enhancing sleep quality substantially attenuated MAFLD prevalence regardless of the volume of PA, whereas, engaging in PA well above current guidelines did not adequately counteract the adverse impacts of poor sleep on MAFLD.

CONCLUSIONS

Public health awareness and strategies concurrently targeting both sleep quality and PA should be encouraged to curb the climbing prevalence of MAFLD.

Prolonged sleep duration as a predictor of cognitive decline: A meta-analysis encompassing 49 cohort studies

Despite numerous studies have explored the association between sleep duration and cognition, the link between sleep duration trajectories and cognition remains underexplored. This systematic review aims to elucidate this correlation. We analyzed 55 studies from 14 countries, comprising 36 studies focusing on sleep duration, 20 on insomnia, and 13 on hypersomnia. A total of 10,767,085 participants were included in 49 cohort studies with a mean follow-up duration of 9.1 years. A non-linear association between sleep duration and cognitive decline was identified. Both long (risk ratio (RR):1.35, 95 % confidence intervals (CIs):1.23-1.48) and short sleep durations (RR: 1.12, 95 % CIs:1.03-1.22) were associated with an elevated risk of cognitive decline compared to moderate sleep duration. Additionally, hypersomnia (RR:1.26, 95 % CIs: 1.15-1.39) and insomnia (RR: 1.16, 95 % CIs: 1.002-1.34) were also linked to an increased risk. Moreover, prolonged sleep duration posed a higher risk of cognitive decline than stable sleep duration (RR:1.42, 95 % CIs:1.27-1.59). Importantly, transitioning from short or moderate to long sleep duration, as well as persistent long sleep duration, exhibited higher RRs for cognitive decline (RRs: 1.94, 1.40, and 1.28, respectively) compared to persistent moderate sleep duration. Our findings underscore the significance of prolonged sleep duration, alongside short and long sleep durations, with an elevated risk of cognitive decline. The association is tied to the degree of sleep duration changes. Our study highlights the importance of considering changes in sleep patterns over time, not just static sleep durations.

Nonrestorative sleep and its association with insomnia severity, sleep debt, and social jetlag in adults: Variations in relevant factors among age groups

OBJECTIVE

Nonrestorative sleep (NRS) is unrefreshing sleep that is harmful to mental and physical health. Although few studies have reported the relationship between NRS and sleep problems, none have evaluated this relationship by age group. This study aimed to determine whether NRS could be associated with insomnia severity, sleep debt, and social jetlag and whether this relationship would vary with age.

METHODS

The 1592 participants were allocated into age groups: 18-25 years (n = 317), 26-40 years (n = 405), 41-65 years (n = 454), and >65 years (n = 416). The study used Restorative Sleep Questionnaire to assess NRS, Athens Insomnia Scale to assess insomnia severity, Sleep Debt Index to assess sleep debt, and the absolute difference in midpoints of sleep between weekdays and days off to assess social jetlag.

RESULTS

Logistic regression analysis was performed to determine the association between NRS and sleep problems. In the 18-25-year group, insomnia severity, sleep debt of ≥2 h, and social jetlag of ≥2 h; in the 26-40-year group, insomnia severity and sleep debt of ≥2 h; in the 41-65-year group, insomnia severity and sleep debt of ≥2 h; and in the >65-year group, insomnia severity were significantly associated with NRS.

CONCLUSION

NRS was associated with insomnia severity in all age groups, with sleep debt in the young and working-age groups and social jetlag in the young age group. Different approaches to improving the NRS are required for different age groups.

Insomnia, Short Sleep, and Their Treatments: Review of Their Associations with Weight

PURPOSE OF REVIEW

Insomnia and short sleep have been linked with weight gain and obesity. However, these findings have not been consistent across studies. We review recent evidence for the association between insomnia, short sleep, and weight gain, as well as the relationship between behavioral and pharmacological treatments for sleep and weight.

RECENT FINDINGS

The relationship between insomnia and obesity is mixed, with stronger associations between insomnia with short sleep and obesity than other presentations of insomnia. Short sleep is associated with weight gain. Z-drugs and benzodiazapines do not appear to impact weight, but many antidepressants and antipsychotics that are used for insomnia treatment do cause weight gain. The relationships between insomnia and short sleep with weight gain and obesity are inconsistent. More prospective trials are needed to identify mediators and moderators of this relationship to better develop and deliver effective interventions for both sleep and weight problems.

Sleep duration and the risk of new-onset arthritis in middle-aged and older adult population: results from prospective cohort study in China

Background

The pain and sleep disorders caused by arthritis are health issues that have been re-emphasized with the aging population. However, the majority of research on arthritis and sleep disorders has focused on cases that have already been diagnosed with arthritis. This research aims to explore the correlation between sleep duration and new-onset arthritis in middle-aged and older adult individuals.

Methods

Utilizing data from the China Health and Retirement Longitudinal Study from baseline (2011) to the Wave 3 follow-up (2018), we conducted a 7-year longitudinal investigation targeting populations with valid sleep questionnaire records and without arthritis. Sleep duration was assessed from nighttime sleep and daytime nap records. The new-onset of arthritis was determined based on self-reported diagnosis. We employed different logistic regression models to consider the potential impact of sleep duration on arthritis and conducted mediation analyses to assess the involvement of BMI in the association between sleep duration and the new-onset risk of arthritis.

Results

Out of the 6,597 individuals analyzed in the cohort, 586 (8.9%) were diagnosed with new-onset arthritis. Median sleep duration was notably shorter in the new-onset arthritis group (6.63 vs. 6.41 h, p < 0.05). There was a notable negative correlation found between new-onset risk of arthritis and sleep duration, with each Interquartile Range (IQR) increment in sleep leading to a 16% risk reduction (OR: 0.864; 95% CI: 0.784-0.954). Stratified analyses revealed BMI as a potential modifier in the sleep-arthritis relationship (P for interaction = 0.05). Mediation analyses further showed that about 3.5% of the association was mediated by BMI. Additionally, the inclusion of sleep duration improved the arthritis predictive power of our model, with an IDI of 0.105 (0.0203, 0.1898) and an NRI of 0.0013 (0.0004, 0.0022) after adding sleep duration to the basic model.

Conclusion

In the middle-aged and older adult demographic of China, increased sleep duration is associated with a decreased new-onset risk of arthritis, with BMI potentially playing a role in mediating this connection.

The mediating effect of sleep duration on metabolic syndrome severity in adults: a structural equation modeling approach

BACKGROUND

Metabolic syndrome (MetS) is associated to sleep duration. It is crucial to identify factors that disrupt sleep regulation. The study aimed to assess the indirect effect of risk factors related to MetS severity through sleep duration by utilizing a structural equation model (SEM).

METHODS

The study involving 3,935 adults from the baseline data of the Ravansar Non-Communicable Disease (RaNCD) cohort study. MetS severity scores were the outcome variables. SEM was employed to explore the relationships, utilizing IBM SPSS and AMOS version 23.

RESULTS

The mean MetS severity score was higher in women compared to men (0.25 vs. 0.16, P = 0.003). In men, socioeconomic status (SES) has a positive direct effect (β = 0.048) and a negative indirect effect (β=-0.006) on MetS severity. Increased physical activity is directly (β=-0.036) and indirectly (β=-0.093) associated with reducing MetS severity. Nap duration is directly linked to an increase (β = 0.072) but has an indirect effect (β=-0.008) in decreasing MetS severity. In women, SES has a direct (β=-0.020) and indirect (β=-0.001) inverse relationship with MetS severity. Increased physical activity is directly (β=-0.048) and indirectly (β=-0.036) associated with decreasing MetS severity in women. Nap duration is directly associated with an increase in MetS severity (β=-0.018) but indirectly contributes to its reduction (β=-0.002). Sleep duration not only directly affects MetS severity but is also influenced by age, SES, physical activity, obesity and nap duration.

CONCLUSION

Physical activity, SES, and nap duration directly and indirectly effect the MetS severity. Sleep duration was recognized as a mediating variable that supports the indirect effects.

Association between Sleep Duration, Social Jetlag, and the Metabolic Syndrome by Shift Works

Lifestyle factors, including sleep characteristics, have been implicated in the development of metabolic syndrome, particularly among shift workers. This study aimed to explore the relationship between shift work, sleep duration, social jetlag, and the risk of metabolic syndrome among U.S. workers and the moderating effect of sleep duration and social jetlag on this relationship. Data from the National Health and Nutrition Examination Survey (NHANES) in 2017-2020 March were analyzed. Poisson regression models were employed to examine associations. Among 4136 U.S. workers, 53.3% had metabolic syndrome, with a higher proportion of shift workers (63.8% vs. 56.7%, p = 0.001) and those sleeping less than 6 h or more than 9 h per week (22.3% vs. 19.1%, p = 0.044) in the affected group. Shift workers were initially found to have an increased risk of metabolic syndrome (Coef. = 0.03, 95% CI: 0.02, 0.16); however, this association was mitigated when accounting for the interaction with social jetlag. Specifically, 1 to <2 h of social jetlag interacted significantly, increasing metabolic risk (Coef. = 0.15, 95% CI: 0.09, 0.22), whereas 1 to <2 h alone showed a protective effect (Coef. = -0.11, 95% CI: -0.17, -0.06). These findings suggest that optimizing sleep schedules and addressing social jetlag may be crucial in mitigating metabolic syndrome risks among shift workers.

The Association between Circadian Syndrome and Frailty in US adults: a cross-sectional study of NHANES Data from 2007 to 2018

PURPOSE

Frailty and Circadian Syndrome (CircS) are prevalent among the elderly, yet the link between them remains underexplored. This study aims to examine the association between CircS and frailty, particularly focusing on the impact of various CircS components on frailty.

MATERIALS AND METHODS

We conducted a cross-sectional analysis using data from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2018. The 49-item Frailty Index (FI) was employed to assess frailty. To understand the prevalence of CircS in relation to frailty, we applied three multivariate logistic regression models. Additionally, subgroup and interaction analyses were performed to investigate potential modifying factors.

RESULTS

The study included 8,569 participants. In fully adjusted models, individuals with CircS showed a significantly higher risk of frailty compared to those without CircS (Odds Ratio [OR] = 2.18, 95% Confidence Interval [CI]: 1.91-2.49, p < 0.001). A trend of increasing frailty risk with greater CircS component was observed (trend test p < 0.001). Age (p = 0.01) and race (p = 0.02) interactions notably influenced this association, although the direction of effect was consistent across subgroups. Sensitivity analysis further confirmed the strength of this relationship.

CONCLUSION

This study identifies a strong positive correlation between CircS and frailty in the elderly. The risk of frailty escalates with an increasing number of CircS components. These findings highlight the intricate interplay between circadian syndrome and frailty in older adults, offering valuable insights for developing targeted prevention and intervention strategies.

Sleep Quality, Nutrient Intake, and Social Development Index Predict Metabolic Syndrome in the Tlalpan 2020 Cohort: A Machine Learning and Synthetic Data Study

This study investigated the relationship between Metabolic Syndrome (MetS), sleep disorders, the consumption of some nutrients, and social development factors, focusing on gender differences in an unbalanced dataset from a Mexico City cohort. We used data balancing techniques like SMOTE and ADASYN after employing machine learning models like random forest and RPART to predict MetS. Random forest excelled, achieving significant, balanced accuracy, indicating its robustness in predicting MetS and achieving a balanced accuracy of approximately 87%. Key predictors for men included body mass index and family history of gout, while waist circumference and glucose levels were most significant for women. In relation to diet, sleep quality, and social development, metabolic syndrome in men was associated with high lactose and carbohydrate intake, educational lag, living with a partner without marrying, and lack of durable goods, whereas in women, best predictors in these dimensions include protein, fructose, and cholesterol intake, copper metabolites, snoring, sobbing, drowsiness, sanitary adequacy, and anxiety. These findings underscore the need for personalized approaches in managing MetS and point to a promising direction for future research into the interplay between social factors, sleep disorders, and metabolic health, which mainly depend on nutrient consumption by region.

Combined Influence of Eight Lifestyle Factors on Metabolic Syndrome Incidence: A Prospective Cohort Study from the MECH-HK Study

Although previous studies have shown significant associations between individual lifestyles and metabolic syndrome, limited studies have explored the combined effect of lifestyles. The purpose of this study was to investigate whether a combined lifestyle score was associated with metabolic syndrome incidence in Hong Kong Chinese women. This prospective cohort study included 1634 women (55.9 ± 8.6 years) without baseline metabolic syndrome, diabetes, myocardial infarction, or stroke. Eight lifestyle factors (smoking, physical activity, sedentary time, sleep, stress, fatigue, diet, and alcohol) were included by assigning 0 (unhealthy) or 1 point (healthy). The overall score was the sum of these points, ranging from 0 (the least healthy) to 8 points (the healthiest). Metabolic syndrome was diagnosed by the joint interim statement. During a 1.16-year follow-up, 179 (11.0%) new metabolic syndrome cases were identified. The incidences for the 0-3-point, 4-point, 5-point, and 6-8-point groups were 12.8% (79/618), 11.5% (42/366), 9.4% (29/309), and 8.5% (29/341), respectively. Compared to the lowest combined lifestyle score group, the highest group had a 47% reduced metabolic syndrome incidence, with an adjusted odds ratio and 95% confidence interval of 0.53 (0.33-0.86) (p = 0.010). These findings indicate that a higher combined lifestyle score was associated with a lower metabolic syndrome incidence in this population.

Meeting the Canadian 24-Hour Movement Guidelines and physical-mental comorbidity among Chinese children and adolescents: Prevalence, associations, and the population impacts

OBJECTIVES

To examine the association between meeting the Canadian 24-Hour Movement Guidelines and physical-mental comorbidity among children and adolescents in a cross-sectional study.

METHODS

A total of 21,061 students aged 11-17 years from Zhejiang Province, China was recruited in the study. We examined the coexistence of five specific physical illnesses - hypertension, high myopia, dental caries, scoliosis, and obesity - with mental illness, specifically depressive symptoms. Generalized linear mixed models were performed to assess the association between overall and specific combinations of movement guidelines and physical-mental comorbidity, presented by odds ratio (OR) and 95% confidence interval (CI). Population attributable fraction (PAF) was calculated to estimate the preventable proportion of comorbid cases via meeting all three movement recommendations.

RESULTS

Of the included participants, 19.3% had physical-mental comorbidity. There were 3.8% and 17.0% meeting all three and none of the recommendations, respectively. Meeting at least one recommendation, except for moderate-to-vigorous physical activity recommendation only, was associated with a lower risk of physical-mental comorbidity, with ORs (95% CIs) ranging from 0.72 (0.66-0.79) to 0.40 (0.31-0.51). Meeting more recommendations was associated with decreased comorbid risks, and the association was stronger in 4th-6th graders. The association between specific combinations of recommendations and comorbid risks showed differences by gender and grade. Of the comorbid cases, 42.1% were attributed to not adhering to all three recommendations, and the PAFs varied from 27.4% to 55.7% across different genders and grades.

CONCLUSION

Adherence to the 24-h movement guidelines was associated with lower risks of physical-mental comorbidity among children and adolescents.

The Association Between Short Sleep Duration and Metabolic Syndrome: A Case-Control Study

Purpose

Short sleep duration and quality are increasingly common in the Middle East and North Africa (MENA) region and has been linked to metabolic syndrome, which increases the risk of cardiovascular disease and diabetes. This study aimed to examine the link between short sleep duration and metabolic syndrome.

Patients and Methods

We conducted a case-control study using data from Qatar Biobank, with 1000 participants categorized into two groups: less than 7 hours of sleep (n=500) and 7 or more hours of sleep (n=500). Metabolic syndrome was defined using WHO criteria, and logistic regression analysis adjusted for age and gender.

Results

There was a higher proportion of individuals with MetS in the short sleep duration group compared to the normal sleep duration group (22.8% vs 15.8%, respectively). The multivariable regression showed that short sleep duration was associated with metabolic syndrome (OR 1.91, 95% CI: 1.14-3.20, P=0.014) and having 1-2 components of metabolic syndrome (OR 1.91, 95% CI: 1.14-3.20, P=0.014), particularly in males (OR: 2.30, 95% CI: 1.07-4.94, P=0.032). Being overweight (OR 2.17, 95% CI: 1.30-3.63, P=0.003) was also associated with a shorter sleep duration. BMI was identified as the main contributor to the association between short sleep duration and metabolic syndrome, while diabetes played a minor role.

Conclusion

Short sleep duration was associated with metabolic syndrome in Qatar, particularly in males.

Objective Sleep Duration and All-Cause Mortality Among People With Obstructive Sleep Apnea

Importance

The association between sleep duration and all-cause mortality remains unclear among people with obstructive sleep apnea (OSA).

Objective

To explore whether there is an association between sleep duration and all-cause mortality among people with OSA.

Design, Setting, and Participants

This cohort study investigated participants with OSA from the Sleep Heart Health Study (SHHS) in which participants were enrolled between 1995 and 1998 with questionnaires and polysomnography (PSG) assessment and followed up for a median of 11.8 years. SHHS was a multicenter community-based study; 2574 participants with OSA defined by apnea-hypopnea index (AHI) greater than or equal to 15 from SHHS were found; all of them had all-cause mortality data and were included in the study. Data were analyzed from November 2022 to October 2023.

Exposures

Participants were divided into 4 groups with objective sleep duration of (1) at least 7 hours, (2) 6 to less than 7 hours, (3) 5 to less than 6 hours, and (4) less than 5 hours, which was determined by total sleep time on PSG at baseline.

Main Outcomes and Measures

All-cause mortality was defined as deaths from any cause and its risk was compared among 4 OSA groups using Cox regression models.

Results

A total of 2574 participants with OSA were included (1628 [63.2%] men and 946 [36.8%] women; mean [SD] age, 65.4 [10.7] years; 211 [8.2%] Black, 2230 [86.6%] White, 133 [5.2%] other race). Overall, 688 all-cause deaths were observed in participants. Compared with the group sleeping at least 7 hours, the groups sleeping 6 to less than 7 hours (hazard ratio [HR], 1.53 [95% CI, 1.13-2.07]), 5 to less than 6 hours (HR, 1.40 [95% CI, 1.03-1.90]), and less than 5 hours (HR, 1.64 [95% CI, 1.20-2.24]) had significantly higher risks of all-cause mortality independent of AHI. Sensitivity analyses were performed among participants with available data of positive airway pressure treatment during follow-up and the finding was mostly consistent, albeit the HR for the group of 5 to less than 6 hours was not statistically significant.

Conclusions and Relevance

In this cohort study of 2574 participants with OSA, those with shorter objective sleep duration had higher risk of all-cause mortality independent of AHI compared with those sleeping at least 7 hours. Further studies would be needed to investigate health benefits of extending sleep length among people with OSA with short sleep duration.

Evaluation of weekend catch-up sleep and weekday sleep duration in relation to metabolic syndrome in Korean adults

PURPOSE

This study aimed to evaluate whether or not the relationship between weekday sleep duration and prevalence of metabolic syndrome (MetS) differs according to weekend catch-up sleep (CUS) in Korean adults.

METHODS

Data from the Korea National Health and Nutrition Examination Survey 2016-2020, including that regarding weekday sleep duration, weekend CUS, MetS components, and confounding factors such as sociodemographic factors, health behaviors, and illness-related factors, were evaluated in Korean adults aged 19 to 80 years. Complex-sample logistic regression was applied after adjusting for confounding factors.

RESULTS

Among 24,313 adults, the prevalence of MetS was lowest in individuals with 6-7 h of sleep on weekdays and CUS ≥ 2 h (17.7%, reference group). The interaction between weekday sleep duration and weekend CUS for MetS was significant. Compared to the reference group, the prevalence of MetS was higher in those who slept < 7 h and had a maximum CUS of 1 h (aORs, 1.42-1.66), and in those who slept ≥ 9 h and had a maximum CUS of 2 h (aORs, 1.28-1.82). In subjects with no CUS or CUS ≥ 2 h, the prevalence of MetS was greater even in those with adequate weekday sleep duration (7- 9 h) than in the reference group (aORs, 1.37 and 1.64, respectively).

CONCLUSION

Weekend CUS may help individuals with short weekday sleep duration reduce their odds of developing MetS, but it may worsen the condition in individuals with a long weekday sleep length.

Device-measured movement behaviours in over 20,000 China Kadoorie Biobank participants

BACKGROUND

Movement behaviours, including physical activity, sedentary behaviour, and sleep have been shown to be associated with several chronic diseases. However, they have not been objectively measured in large-scale prospective cohort studies in low-and middle-income countries. We aim to describe the patterns of device-measured movement behaviours collected in the China Kadoorie Biobank (CKB) study.

METHODS

During 2020 and 2021, a random subset of 25,087 surviving CKB individuals participated in the 3rd resurvey of the CKB. Among them, 22,511 (89.7%) agreed to wear an Axivity AX3 wrist-worn triaxial accelerometer for seven consecutive days to assess their habitual movement behaviours. We developed a machine-learning model to infer time spent in four movement behaviours [i.e. sleep, sedentary behaviour, light intensity physical activity (LIPA), and moderate-to-vigorous physical activity (MVPA)]. Descriptive analyses were performed for wear-time compliance and patterns of movement behaviours by different participant characteristics.

RESULTS

Data from 21,897 participants (aged 65.4 ± 9.1 years; 35.4% men) were received for demographic and wear-time analysis, with a median wear-time of 6.9 days (IQR: 6.1-7.0). Among them, 20,370 eligible participants were included in movement behavior analyses. On average, they had 31.1 mg/day (total acceleration) overall activity level, accumulated 7.7 h/day (32.3%) of sleep time, 8.8 h/day (36.6%) sedentary, 5.7 h/day (23.9%) in light physical activity, and 104.4 min/day (7.2%) in moderate-to-vigorous physical activity. There was an inverse relationship between age and overall acceleration with an observed decline of 5.4 mg/day (17.4%) per additional decade. Women showed a higher activity level than men (32.3 vs 28.8 mg/day) and there was a marked geographical disparity in the overall activity level and time allocation.

CONCLUSIONS

This is the first large-scale accelerometer data collected among Chinese adults, which provides rich and comprehensive information about device-measured movement behaviour patterns. This resource will enhance our knowledge about the potential relevance of different movement behaviours for chronic disease in Chinese adults.

Assessing the Association of Self-Reported Sleep Duration and Metabolic Syndrome Among Middle-Aged and Older Adults in China from the China Health and Retirement Longitudinal Survey

Objectives: We aim to investigate the correlation between sleep and metabolic syndrome (MS) among a community population 45 years of age and older in China. Methods: A cross-sectional analysis of 9096 participants from China health and longitudinal study was carried out. MS was defined by consensus criteria. Sleep durations were assessed by self-reported questionnaire. Odds ratio (OR) and 95% confidence intervals (CIs) for MS were obtained using multivariable-adjusted regression analysis. Results: Long habitual daytime sleep had a positive influence on MS (OR = 1.50, 95% CI = 1.10-2.06). For elderly, short daytime sleep significantly increased risk of MS (OR = 2.14, 95% CI = 1.25-3.67). Females with long daytime sleep was associated with increased risk of MS (OR = 1.54, 95% CI = 1.04-2.29). Conclusions: Daytime sleep significantly increased risk of MS for middle-aged and elderly Chinese. The hazard role of daytime sleep on MS was various between age and sex groups. Results of this study needed to be verified by future longitudinal studies.

Nurse-led models of care for metabolic syndrome in primary care: A scoping review

AIM

To identify and map out existing nurse-led models of care for treatment and prevention of metabolic syndrome in primary care settings.

DESIGN

A scoping review.

METHODS

Conducted in accordance with the JBI methodology.

DATA SOURCES

A search of the databases PubMed, CINAHL Complete, Cochrane Library, Scopus, handsearch and a grey literature search was conducted in June 2022 and updated in March 2023.

RESULTS

Title and abstract screening was performed on 926 articles resulting in 40 articles for full text screening. Full text screening yielded seven articles that met inclusion criteria.

CONCLUSION

Additional research is needed on nursing models of care to prevent and treat metabolic syndrome. Future studies should concentrate on rigour with clearly defined objective inclusion criteria.

IMPLICATIONS TO CLINICAL PRACTICE

This review contributes a synthesis of the evidence on nurse-led models for metabolic syndrome in primary care.

IMPACT

This scoping review addresses metabolic syndrome, the precursor to non-communicable disease. The review mapped the evidence for nurse-led models of care for metabolic syndrome in the primary care setting. These findings promote the development and evaluation of novel nurse-led models of care which can mitigate the effect of the current epidemic.

REPORTING METHOD

PRISMA checklist for scoping reviews. No patient or public contribution was part of this study.

PROTOCOL REGISTRATION

Open Science Framework accessible at: https://osf.io/jfpw7/.

The effect of exercise on the risk of metabolic syndrome associated with sleep insufficiency: a cross-sectional study

Introduction

Sleep disturbance and insufficient sleep have been linked to metabolic syndrome, increasing cardiovascular disease and mortality risk. However, few studies investigate the joint effect of sleep and exercise on metabolic syndrome. We hypothesized that regular exercise can mitigate the exacerbation of metabolic syndrome by sleep insufficiency.

Objective

The aim of this study was to investigate whether exercise can attenuate or eliminate the relationship between sleep insufficiency and metabolic syndrome.

Method

A total of 6,289 adults (mean age = 33.96 years; women: 74.81%) were included in the study, a cross-sectional study conducted based on the results of employee health screening questionnaires and databases from a large healthcare system in central Taiwan. Participants reported sleep insufficiency or not. Self-reported exercise habits were classified into 3 levels: no exercise, exercise <150 min/week, and exercise ≧150 min/week. Multiple logistic regression and sensitivity analyses were conducted to understand the joint associations of sleep patterns and exercise with metabolic syndrome with exposure variables combining sleep duration/disturbances and PA.

Results

Compared with the reference group (sufficient sleep), individuals with sleep insufficiency had a higher risk for metabolic syndrome [adjusted odds ratio (AOR) = 1.40, 95% confidence interval (95% CI): 1.01-1.94, p < 0.05] in females aged 40-64 years, but not in other populations. Sleep insufficiency was not associated with the risk of metabolic syndrome among individuals achieving an exercise level of <150 min/week, and in particular among those achieving ≧150 min/week in all populations in our study.

Conclusion

Sleep insufficiency was related to a higher risk of metabolic syndrome in female healthcare staff aged 40-64 years. Being physically active with exercise habits in these individuals, the risk of metabolic syndrome was no longer significant.

Sleep duration and the risk of major eye disorders: a systematic review and meta-analysis

BACKGROUND

To assess the relationship between sleep duration and the risk of major eye disorders including myopia, glaucoma, cataract, age-related macular degeneration (AMD), and diabetic retinopathy (DR).

METHODS

Databases including PubMed, Embase, Web of Science, and Cochrane library were searched for eligible publications before July 2021. Studies assessing the relationship between sleep duration and any one of the major eye disorders were identified. Pooled odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs) were estimated using random-effects models.

RESULTS

We identified 21 relevant articles including 777348 participants, and 17 were cross-sectional, 3 were longitudinal, and 1 was case-control. Pooled results indicated that long sleep duration was significantly associated with the risk of DR (OR = 1.84, 95% CI 1.24, 2.73), and short sleep duration was significantly associated with the risk of cataract (OR = 1.20, 95% CI 1.05, 1.36). Besides, a significant relationship was observed between the risk of DR and long sleep duration per day (i.e., nighttime sleep plus daytime napping, OR = 1.74, 95% CI 1.23, 2.44) rather than per night (OR = 2.17, 95% CI 0.95, 4.99). The extreme of long sleep duration (i.e., >10 h per night) increased the risk of myopia (OR = 1.02, 95% CI 1.01, 1.04).

CONCLUSIONS

Inappropriate sleep duration might increase the risk of major eye disorders. The findings could contribute to the growing knowledge on the possible relationship between circadian rhythms and eye disorders.

Sleep Deficiency and Cardiometabolic Disease

Epidemiologic studies have demonstrated that short sleep duration is associated with an increased risk of cardio-metabolic health outcomes including cardiovascular disease mortality, coronary heart disease, type 2 diabetes mellitus, hypertension, and metabolic syndrome. Experimental sleep restriction studies have sought to explain these findings. This review describes the main evidence of these associations and possible mechanisms explaining them. Whether sleep extension reverses these now widely acknowledged adverse health effects and the feasibility of implementing such strategies on a public health level is discussed.

Sleep Duration and Sarcopenia: An Updated Systematic Review and Meta-Analysis

OBJECTIVES

In adults, short and long sleep duration has been associated with sarcopenia risk. Studies have shown that various factors, including biological and psychological factors, could be the underlying cause of the association between aberrant sleep duration and sarcopenia risk. In this study, we have qualitatively and quantitatively summarized previously published studies on sleep duration to assess the relationship between sleep duration and sarcopenia risk in adults. This would aid in enhancing our understanding of recent advancements in this field and the association between sleep duration and sarcopenia risk.

DESIGN

Systematic review and meta-analysis.

SETTING AND PARTICIPANTS

In this review, we included studies evaluating the association between the duration of sleep and sarcopenia in adults in observational studies.

METHODS

Five electronic databases (PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure, and Web of Science) were searched to April 20, 2023, to identify studies related to sarcopenia and sleep duration. Next, we calculated the odds ratios (ORs) for sarcopenia prevalence based on the adjusted data from individual studies. Statistical analyses were performed using Stata 11.0.

RESULTS

Sarcopenia prevalence was high (18%) in adults with long sleep duration. Our results showed a significant association between short duration of sleep and high sarcopenia prevalence in older adults (OR 1.2, 95% CI 1.02-1.41, I2 = 56.6%). Furthermore, a significant association was observed between all participants with long-duration sleep and high sarcopenia prevalence (OR 1.53, 95% CI 1.34-1.75, I2 = 56.8%). We also observed significant heterogeneity in the adjusted ORs.

CONCLUSIONS AND IMPLICATIONS

There was a correlation between sarcopenia and short or long sleep duration, especially in older adults. In adults with a long duration of sleep, sarcopenia prevalence was relatively high.

Secular Trends in Sleep Conditions in Chinese Elderly Individuals: A National Population-Based Study

Purpose

As one of the most rapidly aging countries in the world, the elderly population is expected to reach over 400 million in China by 2032. Many studies have suggested a positive association between sleep duration and adverse health events among elderly individuals. This study aimed to investigate the sleep conditions of Chinese elderly individuals between 2005 and 2018.

Patients and methods

Data for 53,013 elderly individuals were taken from five cycles of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) during 2005-2018. Sex- and age-specific means and 95% confidence intervals (95% CIs) were used to estimate sleep duration trends. Changes in sleep patterns were explored during this period. The prevalence of short and long sleep durations was assessed and age-standardized by the 2010 census. Finally, self-reported sleep quality was used to determine sleep conditions from another perspective among elderly individuals.

Results

The mean sleep duration decreased from 7.87 (95% CI: 7.83-7.91) to 7.29 (95% CI: 7.25-7.33) hours between 2005 and 2018. Changes in sleep duration patterns were found during the study period. The proportion of the elderly population who slept ≤6 hours increased and that of those who slept ≥9 hours decreased noticeably over the past 13 years. The age-standardized prevalence of short sleep duration increased from 32.7% (95% CI: 32.7-32.9%) to 38.4% (95% CI: 38.3-38.5%). A significant decrease was observed in the prevalence of long sleep duration.

Conclusion

Sleep conditions are gradually shifting toward a shorter sleep duration and poorer sleep quality among Chinese elderly individuals.

Association between hemoglobin adducts of ethylene oxide levels and the risk of short sleep duration in the general population: an analysis based on the National Health and Nutrition Examination Survey

This study aimed to evaluate the association between blood ethylene oxide (HbEtO) levels and short sleep duration (SSD). Data of 3438 participants aged 20 years or older in this study were collected from the National Health and Nutrition Examination Survey (NHANES). The ethylene oxide (EtO) biomarker (HbEtO) was quantified in blood using a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method. SSD was defined as sleep time equal to or less than 6 h. The analyses utilized weighted logistic regression models and restricted cubic spline. There was a significant non-linear relationship between HbEtO levels and the risk of SSD (P for-nonlinearity = 0.035). After the full adjustment for confounders, compared with the lowest quantile, the odds ratios (ORs) with 95% confidence intervals (CIs) of SSD across the quantiles of ethylene oxide levels were 1.54(1.09-2.18), 1.15(0.87-1.53), and 1.80(1.11-2.92), respectively (P for trend < 0.05). In subgroup analysis, people who were female, who were non-Hispanic Black, who never engaged in physical activity, who consumed alcohol ≤ 14 g/day, who were normal weight or obese had a significantly higher risk of SSD when they had highest quartiles of HbEtO levels than those had lowest (p < 0.05). Our study indicated that HbEtO levels, an indicator for EtO exposure, were associated with SSD in general adult populations.

Sleep Problems Associate With Multimorbidity: A Systematic Review and Meta-analysis

Objectives: To summarize the evidence on the association between sleep problems and multimorbidity. Methods: Six electronic databases (PubMed, Web of Science, Embase, China National Knowledge Infrastructure, VIP, and Wan fang) were searched to identify observational studies on the association between sleep problems and multimorbidity. A random-effects model was used to estimate the pooled odds ratios (ORs) and 95% confidence intervals for multimorbidity. Results: A total of 17 observational studies of 133,575 participants were included. Sleep problems included abnormal sleep duration, insomnia, snoring, poor sleep quality, obstructive sleep apnea (OSA) and restless legs syndrome (RLS). The pooled ORs (95% CIs) for multimorbidity were 1.49 (1.24-1.80) of short sleep duration, 1.21 (1.11-1.44) of long sleep duration and 2.53 (1.85-3.46) for insomnia. The association of other sleep problems with multimorbidity was narratively summarized due to limited number of comparable studies. Conclusion: Abnormal sleep duration and insomnia are associated with higher odds of multimorbidity, while the evidence on association of snoring, poor sleep quality, obstructive sleep apnea and restless legs syndrome with multimorbidity remains inconclusive. Interventions targeting sleep problems should be delivered for better management of multimorbidity.

Sleep duration affects the sequential change of body mass index and muscle strength: a contribution to dynapenic obesity

BACKGROUND

With aging, body mass index (BMI) increases and muscle strength declines, resulting in dynapenic obesity. It remains unknown whether and how sleep duration contributes to the sequence of BMI and muscle strength change in the progression of dynapenic obesity.

METHODS

Data were derived from the first two waves of China Health and Retirement Longitudinal Study. Sleep duration was self-reported. BMI was calculated and grip strength (GS) was measured to reflect muscle strength. The effect of baseline sleep duration on the sequential change of BMI and GS was assessed using two mediation models considering the nonlinear associations between them. The moderating effect of metabolic disorder was also tested.

RESULTS

Totally 4986 participants aged ≥ 50 years (50.8% females) with complete information on variables were included. Baseline BMI fully mediated the nonlinear association between sleep duration and follow-up GS change, but baseline GS did not mediate between sleep duration and follow-up BMI change for older men and women. Short sleep duration positively affected BMI-induced GS change (β = 0.038; 95%CI, 0.015-0.074), while this favorable effect became nonsignificant for moderate sleep duration (β = 0.008; 95% CI, -0.003-0.024) and turned negative with prolonged sleep duration (β =  - 0.022; 95%CI, - 0.051 to - 0.003). This nonlinear mediation effect was more pronounced in older women who are relatively metabolically healthy at baseline.

CONCLUSION

For older adults in China, the influence of sleep duration on BMI-induced GS change but not the GS-induced BMI change suggested the contribution of sleep duration to the sequential course in the progression of dynapenic obesity. Sleep duration deviated either above or below normal range may confer adverse impact on GS through BMI. Strategies addressing sleep and obesity jointly to improve muscle function and delay the progression of dynapenic obesity are required.

The role of sleep and heart rate variability in metabolic syndrome: evidence from the Midlife in the United States study

STUDY OBJECTIVES

Poor sleep and autonomic dysregulation can both disrupt metabolic processes. This study examined the individual and combined effects of poor sleep and reduced heart rate variability (HRV) on metabolic syndrome among 966 participants in the Midlife in the United States II (MIDUS II) study.

METHODS

Self-reported sleep was assessed using the Pittsburgh Sleep Quality Index (PSQI). HRV was acquired from 11-minute resting heart rate recordings. Spearman correlations, general linear regression, and logistic regression models were used to examine the study hypotheses.

RESULTS

Poor sleep quality was associated with metabolic syndrome when global PSQI scores were evaluated as a continuous (odds ratio [OR]: 1.07, 95% confidence interval [CI]: 1.03 to 1.11) or categorical measure (cutoff > 5, OR: 1.58, 95% CI: 1.19 to 2.10), after adjustment for confounding. There also was an association between reduced HRV and metabolic syndrome (ln [HF-HRV] OR: 0.89, 95% CI: 0.80 to 0.99; ln [LF-HRV] OR: 0.82, 95% CI: 0.72 to 0.92; ln [SDRR] OR: 0.59, 95% CI: 0.43 to 0.79; ln [RMSSD] OR: 0.75, 95% CI: 0.60 to 0.94). When the combined effects of poor sleep and low HRV were examined, the association with metabolic syndrome was further strengthened relative to those with normal sleep and HRV.

CONCLUSIONS

To the best of the author's knowledge, this is the first study to suggest a combined effect of poor sleep and low HRV on the odds of metabolic syndrome.

Late, but Not Early, Night Sleep Loss Compromises Neuroendocrine Appetite Regulation and the Desire for Food

OBJECTIVE

There is evidence that reduced sleep duration increases hunger, appetite, and food intake, leading to metabolic diseases, such as type 2 diabetes and obesity. However, the impact of sleep timing, irrespective of its duration and on the regulation of hunger and appetite, is less clear. We aimed to evaluate the impact of sleep loss during the late vs. early part of the night on the regulation of hunger, appetite, and desire for food.

METHODS

Fifteen normal-weight ([mean ± SEM] body-mass index: 23.3 ± 0.4 kg/m²) healthy men were studied in a randomized, balanced, crossover design, including two conditions of sleep loss, i.e., 4 h sleep during the first night-half ('late-night sleep loss'), 4 h sleep during the second night-half ('early-night sleep loss'), and a control condition with 8h sleep ('regular sleep'), respectively. Feelings of hunger and appetite were assessed through visual analogue scales, and plasma ghrelin and leptin were measured from blood samples taken before, during, and after night-time sleep.

RESULTS

Ghrelin and feelings of hunger and appetite, as well as the desire for food, were increased after 'late-night sleep loss', but not 'early-night sleep loss', whereas leptin remained unaffected by the timing of sleep loss.

CONCLUSIONS

Our data indicate that timing of sleep restriction modulates the effects of acute sleep loss on ghrelin and appetite regulation in healthy men. 'Late-night sleep loss' might be a risk factor for metabolic diseases, such as obesity and type 2 diabetes. Thereby, our findings highlight the metabolic relevance of chronobiological sleep timing.

Beyond Counting Sheep: Exploring the Link between Polycystic Ovary Syndrome and Sleep Health

Polycystic ovary syndrome (PCOS) is a common hormonal condition with reproductive, metabolic, and psychological sequelae that affects 8 to 13% of reproductive-aged women and 3 to 11% of adolescent girls. Sleep is often compromised in women with PCOS due to increased rates of sleep problems, with the most established problem being obstructive sleep apnea (OSA). OSA is highly prevalent in reproductive-aged adult women with PCOS, but not so in adolescence. The international evidence-based PCOS guideline to improve health outcomes in women with PCOS indicated routine screening to identify and alleviate symptoms of OSA. The guidelines, however, did not weigh other multidimensional constructs of sleep health such as sleep disturbances (e.g., sleep quality and quantity), beyond OSA. This is perhaps due to the lack of research and existing mixed findings in the area of PCOS and sleep health. This narrative review summarizes the current knowledge about OSA and expands further to include the limited knowledge about other sleep problems in PCOS among reproductive-aged women and adolescent girls. We broadly cover the prevalence, risk factors, and mechanisms of sleep problems in PCOS and their relationship with cardiometabolic and psychological health. A brief summary on treatment and intervention strategies for sleep problems in PCOS and future recommendations will be deliberated.

Relationship Between Sleep Duration and Metabolic Health in Adolescents

Purpose: This study analyzed the gender differences in the cross-sectional relationship between sleep duration and metabolic health in Korean adolescents. Materials and Methods: Adolescents (1234 males, 1073 females) aged 12-19 years who provided their metabolic syndrome score (MetZscore) and sleep duration were included from the Korea National Health and Nutrition Examination Survey 2016-2020 data. Waist circumference (WC), blood pressure (BP), glucose, triglycerides (TGs), and high-density lipoprotein cholesterol (HDL) were combined to create a standardized MetZscore. Gender-specific linear or quadratic relationships between sleep durations (weekday or difference between weekend and weekday sleep) and MetZscore were analyzed after adjusting for age, family affluence, and self-rated health. Results: Male adolescents displayed an inverse linear relationship between weekday sleep duration and MetZscore [B, -0.037 (confidence interval, 95% CI: -0.054 to -0.019)], whereas females showed a nonsignificant relationship. In male adolescents, the standardized scores of WC, BP, and TG decreased linearly as weekday sleep duration increased. In females, weekday sleep duration had an inverse linear association with WC score and a positive quadratic association with glucose score. MetZscore declined linearly as the difference in sleep durations between weekends and weekdays increased [B, -0.078 (95% CI: -0.123 to -0.034) in males; B, -0.042 (95% CI: -0.080 to -0.005) in females]. Although the scores of WC and HDL in males and the scores of WC and glucose in females had inverse linear relationships with the difference in sleep durations, the BP score in males had a positive quadratic association. Conclusions: According to this study, metabolic health benefited from longer weekend sleep durations than weekdays in both male and female adolescents and longer weekdays sleep durations in male adolescents.

Nonrestorative sleep is a risk factor for metabolic syndrome in the general Japanese population

BACKGROUND

This longitudinal study aimed to investigate the effects of nonrestorative sleep on developing metabolic syndrome (MetS) and related diseases in a general Japanese middle-aged population.

METHODS

Overall, 83,224 adults without MetS (mean age: 51.5 ± 3.5 years) from the Health Insurance Association in Japan were followed up for a maximum of 8 years between 2011 and 2019. The Cox proportional hazard method was used to determine whether nonrestorative sleep, assessed using a single-item question, was significantly associated with the respective development of MetS, obesity, hypertension, diabetes, and dyslipidemia. The MetS criteria were adopted by the Examination Committee for Criteria of Metabolic Syndrome in Japan.

RESULTS

The mean follow-up duration was 6.0 years. The incidence rate of MetS was 50.1 person-years/1,000 during the study period. Data suggested that nonrestorative sleep was associated with MetS (hazard ratio [HR]: 1.12, 95% confidence interval [CI]: 1.08-1.16) and other disorders, such as obesity (HR: 1.07, 95% CI: 1.02-1.12), hypertension (HR: 1.07, 95% CI: 1.04-1.11), and diabetes (HR: 1.07, 95% CI: 1.01-1.12) but not with dyslipidemia (HR: 1.00, 95% CI: 0.97-1.03).

CONCLUSIONS

Nonrestorative sleep is associated with the development of MetS and many of its core components in the middle-aged Japanese population. Therefore, assessing nonrestorative sleep may help identify individuals at a risk of MetS development.

Sleep state of the elderly population in Korea: Nationwide cross-sectional population-based study

Objective

Interest in sleep disorders among the elderly, especially those in Korea, has increased. We aimed to describe the overall sleep status of the elderly population in Korea using survey data and to determine the risk factors concerning different aspects of sleep status.

Methods

We conducted a cross-sectional survey on 271 respondents aged 65-86 years old. We performed multistage clustered random sampling according to the population and socioeconomic distribution of all Korean territories. The survey questionnaire was used to perform a structural assessment of sociodemographic characteristics; medical comorbidities; psychiatric comorbidities; and sleep status, including sleep duration, sleep quality, presence of insomnia, excessive daytime sleepiness, sleep apnea, and restless legs syndrome.

Results

Approximately 12.5, 22.%, and 51.3% of the elderly population had poor sleep quality, excessive daytime sleepiness, and insomnia, respectively. Hypertension, dyslipidemia, insomnia, anxiety, and depression predicted poor sleep quality. Female sex, insomnia, and sleep apnea predicted excessive daytime sleepiness. Poor sleep quality and depression predicted insomnia.

Conclusion

A substantial proportion of the elderly Korean population have sleep problems, including poor sleep quality, excessive daytime sleepiness, and insomnia. Sleep status is influenced by various factors, including age, sex, and metabolic and psychiatric comorbidities.

Validation of Fitbit Inspire 2TM Against Polysomnography in Adults Considering Adaptation for Use

PURPOSE

The commercialization of sleep activity tracking devices has made it possible to manage sleep quality at home. However, it is necessary to verify the reliability and accuracy of wearable devices through comparison with polysomnography (PSG), which is the standard for tracking sleep activity. This study aimed to monitor overall sleep activity using Fitbit Inspire 2™ (FBI2) and to evaluate its performance and effectiveness through PSG under the same conditions.

PATIENTS AND METHODS

We compared the FBI2 and PSG data of nine participants (four male and five female participants; average age, 39 years) without severe sleeping problems. The participants wore FBI2 continuously for 14 days, considering the period of adaptation to the device. FBI2 and PSG sleep data were compared using paired t-tests, Bland-Altman plots, and epoch-by-epoch analysis for 18 samples by pooling data from two replicates.

RESULTS

The average values for each sleep stage obtained from FBI2 and PSG showed significant differences in the total sleep time (TST), deep sleep, and rapid eye motion (REM). In the Bland-Altman analysis, TST (P = 0.02), deep sleep (P = 0.05), and REM (P = 0.03) were significantly overstated in FBI2 compared to PSG. In addition, time in bed, sleep efficiency, and wake after sleep onset were overestimated, while light sleep was underestimated. However, these differences were not statistically significant. FBI2 showed a high sensitivity (93.9%) and low specificity (13.1%), with an accuracy of 76%. The sensitivity and specificity of each sleep stage was 54.3% and 62.3%, respectively, for light sleep, 84.8% and 50.1%, respectively, for deep sleep, and 86.4% and 59.1%, respectively for REM sleep.

CONCLUSION

The use of FBI2 as an objective tool for measuring sleep in daily life can be considered appropriate. However, further research is warranted on its application in participants with sleep-wake problems.

Bidirectional Associations between Daytime Napping Duration and Metabolic Syndrome: A Nationally Representative Cohort Study

BACKGROUND

We aimed to examine the bidirectional associations between daytime napping duration and metabolic syndrome (MetS).

METHODS

Using data from the China Health and Retirement Longitudinal Study from 2011 to 2015, modified Poisson regression models were performed to explore the longitudinal associations of baseline napping duration with the occurrence and remission of MetS. Generalized estimating equation was conducted to explore the association between baseline MetS status with subsequent changes in daytime napping duration. Cross-lagged panel analysis was performed to further verify their bidirectional relationships.

RESULTS

During the four-year follow-up, among 5041 participants without MetS at baseline, extended naps were significantly associated with MetS occurrence, compared with non-napping. This association was only significant in individuals with adequate night-time sleep duration or good sleep quality of the 2898 participants with MetS at baseline. Excessive napping duration may be not favorable for MetS remission especially for adequate night-time sleepers. With respect to reverse associations, baseline MetS status significantly increased the napping duration during the subsequent follow-up period. Finally, there were significant bidirectional cross-lagged associations between napping duration and MetS severity score after adjusting for all covariates.

CONCLUSIONS

Our study indicates bidirectional relationships exist between daytime napping duration and MetS. Interestingly, longer napping duration was detrimental to cardiometabolic health only in those with sufficient night-time sleep duration or good sleep quality.

Gender discrepancies in predictors for newly onset cardiovascular events and metabolic syndrome in elderly patients from rural China

Objective

The study aimed to estimate the possible predictors of cardiovascular events (CVEs) in elderly patients with metabolic syndrome (MetS) from rural China. Moreover, we also attempted to find the potential risk factors for newly diagnosed MetS.

Methods

The Northeast China Rural Cardiovascular Health Study (NCRCHS) is a community-based prospective cohort study carried out in rural areas of northeast China. Approximately 1,059 elderly patients with MetS but no cardiovascular diseases and 1,565 elderly patients without MetS at baseline were enrolled in this study. They underwent a physical examination, completed a questionnaire in 2012-2013, and were followed up during 2015-2017. Cox proportional hazard analysis was conducted to assess the possible predictors of newly developed CVEs, and multivariate analysis was used to estimate the risk factors of newly diagnosed MetS.

Results

The common predictors of newly developed CVEs in both men and women were family history of stroke (HR [hazard ratios] _female: 1.696; HR _male: 2.504) and soybean consumption (HR _female: 0.253; HR _male: 0.130). Moreover, minority race (HR: 0.109), systolic blood pressure (SBP) (HR: 1.021), current drinking habits (HR: 2.551), family history of hypertension (HR: 2.297), LDL-C (HR: 1.669), 5,000-20,000 CNY/year annual income (HR: 0.290), and strenuous physical activity (HR: 0.397) were predictors of CVEs only in male elderly patients. For newly diagnosed MetS, body mass index (OR _female: 1.212; OR _male: 1.207) and fasting blood glucose (OR _female: 1.305; OR _male: 1.217) were common risk factors in both genders, whereas age (OR:0.958) was a protective factor in men and > 9-h/day sleep duration (OR:0.212) was a protective factor in women. In addition, SBP (OR:1.014) ≥4 times/day, bean consumption (OR:1.955), and uric acid (OR:1.005) increased the risk of MetS in men but not in women.

Conclusion

Our study identified many effective predictors of CVEs in rural elderly patients with MetS and confirmed the presence of a gender-based discrepancy. Moreover, we also identified additional risk factors, along with the traditional ones, for newly diagnosed MetS in rural elderly patients.

The association between electronic cigarettes, sleep duration, and the adverse cardiovascular outcomes: Findings from behavioral risk factor surveillance system, 2020

The joint effect of electronic cigarette smoking and insufficient sleep duration on cardiovascular disease (CVD) was unclear. This cross-sectional study aimed to evaluate the association between electronic cigarettes, sleep duration, and risk of CVD among American adults. The participants who completed the survey from the behavioral risk factor surveillance system in 2020 were included in this study. The status of electronic cigarette smoking was divided into never, former, and current use. The duration of sleep was categorized into insufficient (<6 h), appropriate (6–9 h), and excessive (>9 h) groups. The CVD group was defined as a patient having any of the following conditions: heart attack, coronary heart disease, or stroke according to self-report. The multivariate logistic regression model was adopted to determine the association between electronic cigarettes, sleep duration, and the risk of CVD. Sensitivity analyses were performed to assess the joint effects on the risk of CVD subtypes, including heart attack, coronary heart disease, and strokes, respectively. Subgroup analyses were performed to estimate the joint effects within the stratum of the age group. The total number of participants included in the present study was 253,561. Of which, 22,908 patients had CVD. In total, 61,293 participants had previously or currently used electronic cigarettes and 37,429 participants had inappropriate sleep duration. Former electronic cigarette users had a 10.8% increased risk of having CVD (OR = 1.108, 95% CI: 1.001–1.227) compared to users who never had electronic cigarettes. Insufficient and excessive sleep durations are associated with increased risks of CVD (OR = 1.592, 95% CI: 1.460–1.735; OR = 1.523, 95% CI: 1.320–1.758). The participants with current vaping status and lack of sleep had a 159.6% increased risk of CVD (OR = 2.596, 95% CI: 1.810–3.723). Sensitivity analyses found similar joint effects of current vaping and insufficient sleep on the risk of heart attack, coronary heart attack, and stroke. The subgroup analyses across each age stratum found that the middle-aged group is most vulnerable to the joint effect of current vaping and insufficient sleep. This study found that both current vaping and inappropriate sleep duration were associated with CVD. Additionally, there was a significant joint effect of current vaping and insufficient sleep on the risk of CVD, especially for middle-aged participants.

Sleep duration, daytime napping, and risk of incident stroke: Nuances by metabolic syndrome from the China health and retirement longitudinal study

Background and purpose

The relationship between sleep duration and stroke are inconclusive in China, especially in those individuals with metabolic syndrome. We aimed to investigate the association between sleep duration and incident stroke in participants with metabolic syndrome or its specific components in China.

Materials and methods

Data were taken from the 2011 and 2015 waves of China Health and Retirement Longitudinal Study (CHARLS). Habitual sleep duration (≤6, 6∼8 [reference], &gt;8 h), daytime napping (0, 1∼60 [reference], and &gt;60 min) were determined by self-reported questionnaires. Metabolic syndrome was defined by blood assessment and biomarkers combined with self-reported doctors’ diagnosis. Incident stroke was determined by reported stroke from 2011 to 2015 wave. Cross-sectional and longitudinal associations between sleep and (incident) stroke at baseline and 4-year follow-up period were tested among the population with metabolic syndrome and its components.

Results

A U-shaped relationship was observed between sleep duration and stroke in cross-sectional analysis. Sleep ≤ 6 h/night had a greater risk of incident stroke (hazard ratio [HR] 1.65; 95% confidence interval [CI] 1.04–2.61) compared with sleep 6∼8 h/night. And the HR of stroke was 1.62 (95%CI, 1.03–2.53) for sleep &lt; 7 h/day compared to 7∼9 h/day. These associations were more evident in the female and individuals aged 45–65 years. Furthermore, the effect of short sleep duration on incident stroke was different in each component of metabolic syndrome, which was more pronounced in participants with elevated blood pressure. And a significant joint effect of sleeping ≤ 6 h/night and no napping on risk of stroke was observed (HR 1.82, 95%CI 1.06–3.12).

Conclusion

Short sleep duration was an independent risk factor for incident stroke, especially among females, individuals aged 45–65 years, or those with some components of metabolic syndrome, such as hypertension. Napping could buffer the risk of short sleep duration on incident stroke.

Sleep Deficiency and Cardiometabolic Disease

Epidemiologic studies have demonstrated that short sleep duration is associated with an increased risk of cardio-metabolic health outcomes including cardiovascular disease mortality, coronary heart disease, type 2 diabetes mellitus, hypertension, and metabolic syndrome. Experimental sleep restriction studies have sought to explain these findings. This review describes the main evidence of these associations and possible mechanisms explaining them. Whether sleep extension reverses these now widely acknowledged adverse health effects and the feasibility of implementing such strategies on a public health level is discussed.

Subjective irregular sleep is associated with metabolic syndrome: A cross-sectional study

Several studies have been reported that sleep duration and circadian rhythms are associated with metabolic syndrome (MetS). However, there are few studies of a relationship between sleep and MetS based on subjective evaluation of sleep regularity. The aim of this study is to examine the relationship between subjective sleep irregularity and metabolic syndrome.

This cross-sectional study included 3,880 participants (1,383 males, 2,497 females) from 2013 to 2017, and we use a self-administered questionnaire to acquire information about sleep (sleep regularity, duration and bedtime). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression analyses to evaluate the associations between sleep regularity and the prevalence of MetS.

The irregularity of sleep was significantly associated with MetS (OR 1.231, 95% CI 1.101–1.375) adjusted for age, sex, METs, sleep duration, bedtime, drinking and smoking statuses, and a history of using sleeping pills. We examined the interaction of MetS with sleep regularity and sleep duration/bedtime, stratified by multiplying the two groups of sleep regularity/irregularity and the three groups of sleep duration/bedtime. Each group of sleep duration/bedtime showed no relationship in the sleep regularity group with MetS, but a significant relationship in the sleep irregularity group. Leptin was significantly elevated in the irregular sleep group regardless of sleep duration and bedtime.

Although many studies have shown a link between sleep and MetS especially in terms of sleep duration, this study showed that irregular sleep is more strongly associated with MetS than sleep duration or bedtime.

Association between Sleep Duration and Mild Cognitive Impairment at Different Levels of Metabolic Disease in Community-Dwelling Older Chinese Adults

OBJECTIVES

The purpose of this study was to investigate the relationship between metabolic syndrome (MetS), sleep duration and mild cognitive impairment (MCI) in community-dwelling older Chinese adults.

METHODS

The study comprised of 1367 community-dwelling Chinese participants (563 men; mean age: 71.0 years) recruited from Tianjin and Shanghai, China who were invited to participate in a comprehensive geriatric assessment. The International Diabetes Federation metabolic syndrome guidelines were used to define MetS. The Mini-Mental State Examination (MMSE) and the Instrumental Activities of Daily Living (IADL) scale were used for the initial classification of patients with MCI. We divided sleep duration into five groups (≤6 h, 6-8 h which was used as the reference, 8-9 h, 9-10 h, and >10 h). Nutritional status was assessed by Mini Nutrition Assessment Short Form.

RESULTS

The overall incidence of metabolic syndrome was 46.7%, the overall incidence of mild cognitive impairment was 17.4%. In logistic regression analysis model, after adjusting for multiple confounding factors such as nutritional status and physical activity level, there was a significant positive association between long sleep duration (> 10h) and mild cognitive impairment in general population and metabolic syndrome population (p<0.05), but the association was not significant in non-metabolic syndrome group. In addition, in the long sleep duration group, the components of metabolic syndrome, elevated blood glucose were significantly associated with mild cognitive impairment (p<0.05).

CONCLUSIONS

Long sleep duration was significantly associated with increased risk of MCI in older adults with MetS, but not in those without MetS. The prevention of MCI may be more effective in the population of MetS with long sleep duration.

The Association Between Sleep and Metabolic Syndrome: A Systematic Review and Meta-Analysis

PURPOSE

Sleep duration is thought to play a key role in the development of metabolic syndrome. However, the results have been inconsistent.

METHODS

We conducted a systematic review and meta-analysis of cohort studies and searched publications in PubMed, Embase, Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov. The summary relative risks (RRs) were estimated using a random model. The sensitivity analysis was performed by sequentially excluding each study to test the robustness of the pooled estimates.

FINDING

We included 13 studies involving 300,202 patients in which short sleep and long sleep significantly increased the risk of metabolic syndrome 15% (RR = 1.15, 95%CI = 1.09-1.22, p < 0.001) and 19% (RR = 1.19, 95%CI = 1.05-1.35, p < 0.001). Moreover, the relationship between sleep duration and metabolic syndrome risk presented a U-shaped curve. Short and long sleep increased the risk of obesity by 14% (RR = 1.14, 95%CI = 1.07-1.22, p<0.001) and 15% (RR = 1.15, 95%CI = 1.00-1.30, p = 0.04), and high blood pressure 16% (RR = 1.16, 95%CI = 1.02-1.31, p = 0.03) and 13% (RR = 1.13, 95%CI = 1.04-1.24, p = 0.01), respectively. Short sleep can potentially increase the risk of high blood sugar by 12% (RR = 1.12, 95%CI = 1.00-1.15, P = 0.05).

IMPLICATIONS

Based on our findings, sleep is a behavior that can be changed and is economical. Clinically doctors and health professionals should be encouraged to increase their efforts to promote healthy sleep for all people.