The effect of short sleep duration on coronary heart disease risk is greatest among those with sleep disturbance: a prospective study from the Whitehall II cohort

Understanding the pathophysiological mechanisms of cardiometabolic complications in obstructive sleep apnoea: towards personalised treatment approaches

In January 2019, a European Respiratory Society research seminar entitled "Targeting the detrimental effects of sleep disturbances and disorders" was held in Dublin, Ireland. It provided the opportunity to critically review the current evidence of pathophysiological responses of sleep disturbances, such as sleep deprivation, sleep fragmentation or circadian misalignment and of abnormalities in physiological gases such as oxygen and carbon dioxide, which occur frequently in respiratory conditions during sleep. A specific emphasis of the seminar was placed on the evaluation of the current state of knowledge of the pathophysiology of cardiovascular and metabolic diseases in obstructive sleep apnoea (OSA). Identification of the detailed mechanisms of these processes is of major importance to the field and this seminar offered an ideal platform to exchange knowledge, and to discuss pitfalls of current models and the design of future collaborative studies. In addition, we debated the limitations of current treatment strategies for cardiometabolic complications in OSA and discussed potentially valuable alternative approaches.

Independent and combined associations of sleep duration and sleep quality with common physical and mental disorders: Results from a multi-ethnic population-based study

Sleep duration and sleep quality are often linked to increased risk of mortality and morbidity. However, national representative data on both sleep duration and sleep quality and their relationship with chronic health problems are rarely available from the same source. This current study aimed to examine the independent and combined associations of sleep duration and sleep quality with physical and mental disorders, using data from the Singapore Mental Health Study 2016. 6,126 residents aged ≥18years participated in this epidemiological, cross-sectional survey. Sleep measures were assessed using the Pittsburg Sleep Quality Index while lifetime or 12-month medical and psychiatric diagnoses were established using the Composite International Diagnostic Interview 3.0. Both short sleep (<6hrs compared to 7-8hrs) and poor sleep were found to be independently associated with chronic pain, obsessive compulsive disorder and any mental disorder while poor sleep was additionally associated with major depressive disorder, bipolar disorder, generalized anxiety disorder and any physical disorder, when adjusted for confounders. Poor sleep combined with short sleep (≤6hrs/day vs 7-8hrs/day) was associated with the highest number of comorbidities among other sleep combinations. Sleep duration and sleep quality, when adjusted for each other, remained independently associated with both physical and mental disorders. Affective disorders may be more closely related to poor sleep quality compared to abnormal sleep duration. Our findings suggest sleep quality to be a more important indicator for psychological and overall health compared to sleep duration.

The mutual association between dyspnea and depressive symptoms in older adults: a 4-year prospective study

Objectives: dyspnea in daily living (DDL), night-time dyspnea (NTD) and depression are common symptoms in older people. However, how changes in dyspnea may influence and be influenced by modifications in depressive symptoms, so far has not been fully evaluated. We aimed to estimate the extent to which both DDL and NTD could be mutually associated to depressive symptoms in older adults with chronic conditions.Methods: this prospective study includes 2322 community-dwelling individuals aged ≥65 years enrolled in the Progetto Veneto Anziani (Pro.V.A.). At baseline and after 4.4 years, we evaluated the following parameters: DDL, assessed by the Medical Research Council dyspnea scale (MRC); self-reported NTD, assessed by personal interview; depressive symptoms, assessed using the Geriatric Depression Scale (GDS). The strength of the association between dyspnea and depression over the follow-up was evaluated through logistic regression and estimated by odds ratios and 95%Confidence Intervals (95%CI). Corrected risk ratios (RR) were then approximated from odds ratios.Results: GDS changes over the follow-up positively correlated with MRC changes (β = 0.938). Individuals with baseline DDL or NTD and those with incident/worsening DDL showed higher risk of developing or worsening depressive symptoms compared with their counterparts (RR = 3.36 [95%CI 2.11-5.06] for incident depression in people with worsening DDL). Incident or persistent depression increased more than twice the risk of developing DDL and NTD (for incident depression RR = 2.33 [95%CI 1.85-2.83] for DDL, and RR = 2.01 [95%CI 1.27-3.11] for NTD).Conclusions: older people may benefit from a comprehensive evaluation of respiratory and psychological symptoms, which seem to be related to each other in advanced age.

On the use of actigraphy in clinical evaluation of diurnal blood pressure profile

A disturbed diurnal blood pressure profile is one of the most important risk factors of cardiovascular diseases. This review analyzes the use of simultaneous diurnal ambulatory blood pressure monitoring (ABPM) and motion activity monitoring (actigraphy) to obtain additional information for correct interpretation of ABPM results in clinically significant decision-making. The article considers practical aspects of actigraphy in expert ABPM for clock-independent calculation of the parameters of nighttime and daytime blood pressure (BP); detection of BP changes during sleep; connection with respiratory disturbances during sleep, motion activity, and body position; and sleep deprivation in shift workers. Original illustrations of simultaneous ABPM and actigraphy are provided.

Chawla N. Deviations from normal bedtimes are associated with short-term increases in resting heart rate

Despite proper sleep hygiene being critical to our health, guidelines for improving sleep habits often focus on only a single component, namely, sleep duration. Recent works, however, have brought to light the importance of another aspect of sleep: bedtime regularity, given its ties to cognitive and metabolic health outcomes. To further our understanding of this often-neglected component of sleep, the objective of this work was to investigate the association between bedtime regularity and resting heart rate (RHR): an important biomarker for cardiovascular health. Utilizing Fitbit Charge HRs to measure bedtimes, sleep and RHR, 255,736 nights of data were collected from a cohort of 557 college students. We observed that going to bed even 30 minutes later than one's normal bedtime was associated with a significantly higher RHR throughout sleep (Coeff +0.18; 95% CI: +0.11, +0.26 bpm), persisting into the following day and converging with one's normal RHR in the early evening. Bedtimes of at least 1 hour earlier were also associated with significantly higher RHRs throughout sleep; however, they converged with one's normal rate by the end of the sleep session, not extending into the following day. These observations stress the importance of maintaining proper sleep habits, beyond sleep duration, as high variability in bedtimes may be detrimental to one's cardiovascular health.

The future of sleep health: a data-driven revolution in sleep science and medicine

In recent years, there has been a significant expansion in the development and use of multi-modal sensors and technologies to monitor physical activity, sleep and circadian rhythms. These developments make accurate sleep monitoring at scale a possibility for the first time. Vast amounts of multi-sensor data are being generated with potential applications ranging from large-scale epidemiological research linking sleep patterns to disease, to wellness applications, including the sleep coaching of individuals with chronic conditions. However, in order to realise the full potential of these technologies for individuals, medicine and research, several significant challenges must be overcome. There are important outstanding questions regarding performance evaluation, as well as data storage, curation, processing, integration, modelling and interpretation. Here, we leverage expertise across neuroscience, clinical medicine, bioengineering, electrical engineering, epidemiology, computer science, mHealth and human-computer interaction to discuss the digitisation of sleep from a inter-disciplinary perspective. We introduce the state-of-the-art in sleep-monitoring technologies, and discuss the opportunities and challenges from data acquisition to the eventual application of insights in clinical and consumer settings. Further, we explore the strengths and limitations of current and emerging sensing methods with a particular focus on novel data-driven technologies, such as Artificial Intelligence.

Sleep patterns, genetic susceptibility, and incident cardiovascular disease: a prospective study of 385 292 UK biobank participants

AIMS

To quantify the association of combined sleep behaviours and genetic susceptibility with the incidence of cardiovascular disease (CVD).

METHODS AND RESULTS

This study included 385 292 participants initially free of CVD from UK Biobank. We newly created a healthy sleep score according to five sleep factors and defined the low-risk groups as follows: early chronotype, sleep 7-8 h per day, never/rarely insomnia, no snoring, and no frequent excessive daytime sleepiness. Weighted genetic risk scores of coronary heart disease (CHD) or stroke were calculated. During a median of 8.5 years of follow-up, we documented 7280 incident CVD cases including 4667 CHD and 2650 stroke cases. Compared to those with a sleep score of 0-1, participants with a score of 5 had a 35% (19-48%), 34% (22-44%), and 34% (25-42%) reduced risk of CVD, CHD, and stroke, respectively. Nearly 10% of cardiovascular events in this cohort could be attributed to poor sleep pattern. Participants with poor sleep pattern and high genetic risk showed the highest risk of CHD and stroke.

CONCLUSION

In this large prospective study, a healthy sleep pattern was associated with reduced risks of CVD, CHD, and stroke among participants with low, intermediate, or high genetic risk.

Effects of Sleep Duration on Cardiovascular Events

PURPOSE OF REVIEW

Sleep is an essential component of human health, and suboptimal sleep duration has been associated with increased cardiovascular morbidity and mortality. This review summarizes physiological and pathological effects of sleep duration on the cardiovascular system.

RECENT FINDINGS

Both decreased and increased duration of sleep lead to increased cardiovascular mortality and has a U-shaped curve. Sleep apnea is an independent risk factor for atherosclerosis and hypertension, and its treatment with continuous positive airway pressure (CPAP) results in increased survival. Estimated sleep duration of 6-8 h is associated with decreased mortality and major cardiovascular events and should be addressed by clinicians during routine visits.

Sleep duration and risk of cardiovascular events: The SAVE study

Background and aim

Controversy exists regarding cardiovascular risk in relation to sleep duration. We determined sleep duration and major recurrent cardiovascular event associations in patients with obstructive sleep apnoea and established cardiovascular disease.

Methods

Secondary analyses of the international, multicenter, Sleep Apnea Cardiovascular Endpoints trial. Sleep duration was estimated from overnight home oximetry (ApneaLink monitor) used for obstructive sleep apnoea diagnosis. Cox proportional hazards models were used to determine associations of categorized sleep duration (<6 h, 6–8 h (reference), and >8 h) and major cardiovascular outcomes: primary composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and any hospitalization for unstable angina, heart failure, or transient ischemic attack; secondary composite of cardiac and cerebral (stroke/transient ischemic attack) events.

Results

Oximetry-derived sleep duration estimates were available in 2687 participants (mean 61.2 years, 80.9% males) who experienced a total of 436 cardiovascular events over a mean follow-up of 3.7 years. Compared to the reference category, sleep duration was not associated with risk of the primary composite cardiovascular outcome (adjusted hazard ratio (HR) 1.00, 95% confidence interval 0.76–1.33, and HR 1.22, 95% confidence interval 0.98–1.52, for sleep duration <6 and >8 h, respectively). However, long sleep was associated with increased cerebral events (HR 1.67, 95% confidence interval 1.17–2.39; P = 0.005) and stroke alone (HR 1.79, 95% confidence interval 1.22–2.63; P = 0.003).

Conclusions

Long sleep duration is associated with an increased risk of stroke but not cardiac events in obstructive sleep apnoea patients with existing cardiovascular disease.

Clinical trial registration

The trial is registered at ClinicalTrials.gov (NCT00738179).

Short Sleep, Insomnia, and Cardiovascular Disease

PURPOSE OF REVIEW

This review summarizes key findings linking insomnia, short sleep duration, and cardiovascular health.

RECENT FINDINGS

Early studies associations between insomnia with short sleep and cardiovascular disease Recent studies have incorporated objective data to assess sleep and identify comorbid sleep disorders (e.g. sleep apnea). Use of objective metrics has facilitated understanding of the impacts of insufficient sleep on autonomic dysregulation, metabolic syndrome, coronary artery disease and overall cardiovascular mortality. Emerging research suggests treatment of insomnia (CBT-I) may be beneficial in terms of reducing cardiovascular disease risk.

SUMMARY

From short term effects on the autonomic nervous system to lasting effects on metabolic syndrome and coronary artery disease, there is growing evidence to support a physiologic pathway by which insomnia with short sleep contributes to cardiovascular disease. More research is needed to understand the effect of insomnia treatment on cardiovascular risk.

The effects of a sleep/recovery supplement: 'Night Time Recharge' on sleep parameters in young adults

BACKGROUND

Concentrated cherry juice reportedly contains melatonin which, in turn, has been highlighted as an important regulator in initiating sleep.

AIM

The present investigation aims to clarify whether Night Time Recharge (NTR), a marketed sleep aid containing cherry extract, improves key sleep parameters in young, active adults with mildly poor sleep.

METHODS

A double-blind, randomized, placebo-controlled, cross-over study design was employed. Twenty participants (nine female) consumed either NTR or a placebo for seven days. Accelerometers were used to assess sleep quality and physical activity levels. Urinary levels of 6-sulphatoxymelatonin (6-SMT), a marker of melatonin synthesis, was assessed via enzyme-linked immunosorbent assay.

RESULTS

6-SMT levels increased following NTR treatment (28.95 ng/ml) compared with placebo (4.0 ng/ml) (p < 0.001). There was also a significant difference (p = 0.047) in dietary tryptophan consumption during the NTR treatment (1236 mg) versus placebo (1149 mg). No trace of melatonin was detected from our analysis of the supplement. NTR had no significant effect on any sleep parameters with the exception of sleep latency (p = 0.001).

CONCLUSIONS

As chemical analysis of NTR by liquid-chromatography mass-spectrometry identified no detectable melatonin, the tryptophan content of the supplement is a likely reason for improvement in sleep latency. These results are in contrast to previous studies which have found a positive effect on sleep following cherry supplementation. Future work should focus on sleep latency and investigating whether cherry juice is effective in participants with problems in initiating sleep.

Application of health behaviour theory to sleep health improvement

Although sleep hygiene is often used for broad sleep health promotion efforts, sleep hygiene education programmes are largely ineffective. These programmes are limited by their lack of a theoretical foundation. Health behaviour theory (HBT) has been used for decades to successfully predict and modify many health behaviours, but its use in the study of sleep health is rare. The purpose of this review is threefold. First, four dominant HBTs will be introduced. Second, the brief literature on HBT and sleep health will be reviewed. Lastly, a translational research agenda will be proposed. The present review concludes that HBT shows potential in both the prediction and modification of sleep health, and that there are several short- and long- term research goals to advance these efforts.

Insomnia symptoms and risk of cardiovascular diseases among 0.5 million adults: A 10-year cohort

OBJECTIVE

To examine the associations of individual insomnia symptoms with risks of incident cardio-cerebral vascular diseases (CVD) and possible moderating factors among Chinese adults.

METHODS

The China Kadoorie Biobank is a prospective cohort study that recruited participants from 10 areas across China. Data from 487,200 adults 30 to 79 years of age who were free of stroke, coronary heart disease, and cancer at baseline were analyzed. Three insomnia symptoms were assessed with self-reported difficulties in initiating or maintaining sleep, early morning awakening, and daytime dysfunction for at least 3 d/wk at baseline. Incidences of CVD were followed up through disease registries and national health insurance databases until 2016.

RESULTS

During a median of 9.6 years of follow-up, 130,032 cases of CVD were documented. Cox regressions showed that 3 insomnia symptoms were associated with increased risk of total CVD, with respective adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of 1.09 (95% CI 1.07-1.11), 1.07 (95% CI 1.05-1.09), and 1.13 (95% CI 1.09-1.18). Participants with individual symptoms also had higher risks of ischemic heart disease (IHD; HR 1.13, 1.09, and 1.17) and ischemic stroke but not hemorrhagic stroke. Participants with all 3 symptoms were at an 18%, 22%, or 10% higher risk of CVD, IHD, or ischemic stroke compared to nonsymptomatic adults. Associations between 3 symptoms and CVD incidence were consistently stronger in younger adults or those without baseline hypertension (p for interaction <0.05).

CONCLUSIONS

Individual and coexisting insomnia symptoms are independent risk factors for CVD incidence, especially among young adults or adults who have not developed hypertension.

The Effect of Long Working Hours and Overtime on Occupational Health: A Meta-Analysis of Evidence from 1998 to 2018

There has been no subsequent meta-analysis examining the effects of long working hours on health or occupational health since 1997. Therefore, this paper aims to conduct a meta-analysis covering studies after 1997 for a comparison. A total of 243 published records were extracted from electronic databases. The effects were measured by five conditions, namely, physiological health (PH), mental health (MH), health behaviours (HB), related health (RH), and nonspecified health (NH). The overall odds ratio between long working hours and occupational health was 1.245 (95% confidence interval (CI): 1.195-1.298). The condition of related health constituted the highest odds ratio value (1.465, 95% CI: 1.332-1.611). The potential moderators were study method, cut-point for long weekly working hours, and country of origin. Long working hours were shown to adversely affect the occupational health of workers. The management on safeguarding the occupational health of workers working long hours should be reinforced.

Sleepless in Beirut: sleep duration and associated subjective sleep insufficiency, daytime fatigue, and sleep debt in an urban environment

PURPOSE

Insufficient sleep is not well studied in developing countries. We assessed sleep duration among adults in Lebanon and examined its potential predictors and relationship with subjective sleep insufficiency, daytime fatigue, and weekday sleep debt.

METHODS

This cross-sectional study included 501 adults (mean age 45.2 (SD15.2) years, 64% females) from the community in Beirut and Mount Lebanon. Socio-demographic, lifestyle and health characteristics, subjective sleep insufficiency, daytime fatigue, and weekday sleep debt (weekend vs. weekdays sleep duration) were compared between individuals who reported sleeping < 6:00, 6-7:59(reference), or ≥ 8:00 h/night. Symptoms and predictors of sleep duration were assessed using logistic regression.

RESULTS

Thirty-nine percent of participants reported sleeping < 6 h/night while 15% reported sleeping ≥ 8:00 h/night. Age (OR = 1.16/year, 95% CI [1.02-1.33]) and female sex (OR = 1.71, 95% CI [1.14-2.58]) were significant predictors of short sleep (< 6:00 h/night) in multivariable adjusted analyses. Compared to referent (6:00-7:59 h/night) and long sleepers (≥ 8:00 h/night), short sleepers were significantly more likely to report subjective sleep insufficiency (OR = 3.00, 95% CI [2:00-4.48], and OR = 4.52, 95% CI [2.41-8.51]; respectively) and daytime fatigue (OR = 1.53, 95% CI [1.04-2.24], and OR = 1.83, 95% CI [1.06-2.04]; respectively). Compared to long weekdays sleepers, short and referent weekdays sleepers were more likely to sleep longer on weekend (OR = 2.47, 95% CI [1.18-5.15], and OR = 4.16, 95% CI [2.03-8.5]; respectively).

CONCLUSIONS

Short sleep is highly prevalent in this urban cohort from a low- to medium-income country especially among women and older adults, and is associated with subjective sleep insufficiency, daytime fatigue, and weekday sleep debt. The socio-cultural determinants of sleep duration need to be studied across different populations to better evaluate the causes and implications of short sleep.

Association between sleep duration, sleep quality and hyperlipidemia in middle-aged and older Chinese: The Dongfeng–Tongji Cohort Study

Aims

This study aimed to evaluate the relationship between sleep duration, sleep quality and hyperlipidemia in middle-aged and older Chinese.

Methods

We included 20,712 individuals at baseline from September 2008 to June 2010, and they were followed-up until October 2013. Hyperlipidemia was defined according to the Chinese guidelines on the prevention and treatment of dyslipidemia in adults. Sleep duration was self-reported and sleep quality was evaluated with a questionnaire that was designed according to the Pittsburgh Sleep Quality Index. Logistic regression and Cox proportional hazard models were conducted to explore the associations.

Results

In the cross-sectional analyses, longer sleep duration (≥10 h) was significantly associated with higher prevalence of hyperlipidemia (odds ratio (OR) = 1.17, 95% confidence interval (CI) = 1.02–1.35) after adjusting for potential confounders. The ORs of hyperlipidemia were significantly elevated among participants with impaired sleep quality (OR = 1.14, 95% CI = 1.08–1.22) and poor sleep quality (OR = 1.20, 95% CI = 1.08–1.34) when compared to those with good sleep quality. In the longitudinal analyses, compared to participants with a sleep duration of 7–<8 h, those with a sleep duration of 9–<10 h (hazard ratio (HR) = 1.19, 95% CI = 1.04–1.35) and ≥10 h (HR = 1.27, 95% CI = 1.02–1.58) showed significantly higher risk of hyperlipidemia after adjusting for potential confounders. However, no statistically significant association was found between impaired or poor sleep quality and hyperlipidemia.

Conclusions

Longer sleep duration was significantly associated with higher risk of hyperlipidemia. Impaired or poor sleep quality were associated with elevated prevalence of hyperlipidemia, but not with the incidence of hyperlipidemia.

Efficacy of individualized homeopathic treatment of insomnia: Double-blind, randomized, placebo-controlled clinical trial

BACKGROUND

Insomnia is the most common sleep-related complaint associated with impaired day-time functioning, reduced quality of life, increased morbidity and substantial societal cost. We evaluated whether individualized homeopathy (IH) could produce significant effect beyond placebo in treatment of insomnia.

METHODS

In this double-blind, randomized, placebo-controlled, two parallel arms trial, 60 patients were randomized to receive either IH/verum or control/placebo (1:1). Patient-administered sleep diary (6 items; 1: latency to fall asleep, 2: minutes awake in middle of night, 3: minutes awake too early, 4: hours spent in bed, 5: total sleep time in hours, and 6: sleep efficiency) and Insomnia Severity Index (ISI) were taken as the primary and secondary outcomes respectively, measured at baseline, and after 3 months.

RESULTS

Five patients dropped out (verum: 2, control: 3). Intention to treat sample (n = 60) was analyzed. Trial arms were comparable at baseline. In the verum group, except sleep diary item 3 (P =  0.371), rest of the outcomes improved significantly (all P < 0.01). In the control group, there were significant improvements in diary item 6 and ISI score (P < 0.01) and just significant improvement in item 5 (P =  0.018). Group differences were significant for items 4, 5 and 6 (P < 0.01) and just significant (P =  0.014) for ISI score with moderate to large effect sizes; but non-significant (P > 0.01) for rest of the outcomes.

CONCLUSION

IH seemed to produce significantly better effect than placebo. Rigorous trials and independent replications are warranted.

Sleep duration and apolipoprotein B in metabolically healthy and unhealthy overweight/obese phenotypes: a cross-sectional study in Chinese adults

OBJECTIVES

Short sleep duration is independently associated with an increased risk of developing cardiovascular disease; however, the association has not yet been examined in obese populations. We assessed the associations between sleep duration, metabolic phenotype and apolipoprotein variables in a nationally representative Chinese population with overweight/obesity.

STUDY DESIGN

Cross-sectional study.

SETTINGS

The study conducted in nine provinces of China that vary substantially in geography and economic development.

PATIENTS

Data were obtained from 4149 adults with overweight/obesity aged 18 to 94 years from the 2009 China Health and Nutrition Survey. Sleep duration was categorised as ≤6, 7-8 or ≥9 hour. Phenotypes were determined based on body mass index and metabolic health status and categorised as metabolically healthy overweight/obesity (MHOO) and metabolically unhealthy overweight/obesity (MUOO).

MAIN OUTCOME MEASURE

The outcome variables were elevated apolipoproteins.

RESULTS

Compared with MHOO phenotype, MUOO phenotypes were more likely to report shorter sleep duration (12.2%vs9%). In the MUOO group, the multivariate-adjusted OR (95% CI) for elevated apolipoprotein B (apoB) was 1.66 (1.23 to 2.23) for those with ≤6 hours of sleep and 1.12 (0.86 to 1.45) for those with ≥9 hours of sleep, using 7-8 hours of sleep as a reference. Similar results were obtained in the subgroup of subjects who were ≥45 or<45 years old, but shorter sleep duration was more strongly associated with elevated apoB in those <45 years (p interaction=0.023). However, no association was observed in the MHOO phenotype.

CONCLUSIONS

The high prevalence of short sleep duration and its strong association with elevated apoB in adults who are metabolically unhealthy overweight/obese suggest an increased risk of cardiovascular disease in this population. The differences in sleep sufficiency among obese phenotypes may account for the disparities in their cardiovascular outcomes.

Lifestyle behaviours and perceived well-being in different fire service roles

Background

Aspects of the work environment influence employee well-being. However, it is unclear how employee lifestyle behaviours, health characteristics and well-being may differ within a broader occupational sector.

Aims

To investigate the health characteristics, lifestyle behaviours and well-being of three Fire and Rescue Service (FRS) occupational groups that differ in shift work and occupational demands: operational firefighters (FF), emergency control (EC) and administrative support (AS) workers.

Methods

Data were obtained via an online survey using previously validated questionnaires to assess health characteristics, lifestyle behaviours and perceived well-being. Differences between groups were explored, controlling for confounding variables, using analysis of covariance (ANCOVA) methods. Effect sizes are reported where appropriate to demonstrate clinical significance.

Results

Four thousand five hundred and sixty-four FRS personnel volunteered, with 3333 (73%) completing the survey out of a total workforce of 60000 (8%). FF reported the lowest prevalence of chronic medical conditions (10%), compared with AS (21%) and EC (19%) workers. Total physical activity (PA) was 66% higher among FF compared with EC and AS workers. Components of sleep and self-rated health were independent predictors of well-being irrespective of FRS role.

Conclusions

FF reported the highest levels of PA and highest perceptions of well-being, and the lowest prevalence of obesity and chronic medical conditions, compared with other FRS occupational groups. These findings may be used to inform FRS workplace intervention strategies.

Association between sleep duration and electrocardiographic ischemic changes in middle-aged population: Isfahan Healthy Heart Program

BACKGROUND

Recent studies examining the association between sleep duration and cardiovascular disease (CVD) showed inconsistent results. The aim of our study was to evaluate the association between self-reported night sleep duration and ischemic changes in electrocardiography (ECG).

METHODS

We conducted this cross-sectional study on 3513 participants from Iranian middle-aged population as a part of Isfahan Healthy Heart Program (IHHP), Isfahan, Iran. Sleep duration was obtained by questioning participants. The frequency of electrocardiographic ischemic changes was calculated using ECG Minnesota coding system.

RESULTS

Short sleep duration was associated with increased frequency of electrocardiographic ischemic changes. In a fully adjusted multiple logistic regression analysis, the odds ratio (OR) for short sleep duration less than 5 hours per night was 1.501 [95% confidence interval (CI) for OR: 1.085-2.076] compared to 8 hours of sleep. After stratifying the study population into sex groups, the association remained significant only in women. The OR for short sleep less than 5 hours per night was 1.565 (95% CI for OR: 1.052-2.329) and 1.455 (95% CI for OR: 0.833-2.539) in women and men, respectively. There was no association between long sleep duration and electrocardiographic ischemic changes in men and women.

CONCLUSION

We concluded that there is a positive association between short sleep duration and frequency of electrocardiographic ischemic changes in middle-aged women. This association suggests that short sleep duration may increase the risk of ischemic heart disease (IHD) in women, and this need to be evaluated in further studies.

Self-Reported Sleep Duration and Quality and Cardiovascular Disease and Mortality: A Dose-Response Meta-Analysis

Background There is growing evidence that sleep duration and quality may be associated with cardiovascular harm and mortality. Methods and Results We conducted a systematic review, meta-analysis, and spline analysis of prospective cohort studies that evaluate the association between sleep duration and quality and cardiovascular outcomes. We searched MEDLINE and EMBASE for these studies and extracted data from identified studies. We utilized linear and nonlinear dose-response meta-analysis models and used DerSimonian-Laird random-effects meta-analysis models of risk ratios, with inverse variance weighting, and the I2 statistic to quantify heterogeneity. Seventy-four studies including 3 340 684 participants with 242 240 deaths among 2 564 029 participants who reported death events were reviewed. Findings were broadly similar across both linear and nonlinear dose-response models in 30 studies with >1 000 000 participants, and we report results from the linear model. Self-reported duration of sleep >8 hours was associated with a moderate increased risk of all-cause mortality, with risk ratio , 1.14 (1.05-1.25) for 9 hours, risk ratio, 1.30 (1.19-1.42) for 10 hours, and risk ratio, 1.47 (1.33-1.64) for 11 hours. No significant difference was identified for periods of self-reported sleep <7 hours, whereas similar patterns were observed for stroke and cardiovascular disease mortality. Subjective poor sleep quality was associated with coronary heart disease (risk ratio , 1.44; 95% confidence interval, 1.09-1.90), but no difference in mortality and other outcomes. Conclusions Divergence from the recommended 7 to 8 hours of sleep is associated with a higher risk of mortality and cardiovascular events. Longer duration of sleep may be more associated with adverse outcomes compared with shorter sleep durations.

Disparities in sleep duration and restedness among same- and different-sex couples: findings from the American Time Use Survey

Study Objectives

The importance of sleep for health necessitates investigation of disparities in multiple aspects of sleep. Given the potential disruption to sleep posed by the well-documented discrimination experienced by sexual minorities, disparities related to sexual minority status warrant such attention. This study sought to (1) measure differences in same- and different-sex couples in sleep duration and perceived restedness, (2) examine how the link between sleep duration and restedness varied among same- and different-sex couples, and (3) assess variation in restedness across state-level sexual minority indicators.

Methods

Participants in the Wellbeing Module of the American Time Use Survey, assessed in 2010, 2012, and 2013 (n = 17378), completed time diaries assessing sleep duration and evaluated their own restedness.

Results

Multinomial and ordinal regression analyses showed no links between partner sex and sleep among men. Women with same-sex partners reported lower restedness than women with different-sex partners, and perceptions of restedness were more strongly linked to sleep duration for the former than the latter. Finally, women with the same-sex partners living in states more supportive of sexual minorities reported better restedness than those in less supportive states.

Conclusions

Women with same-sex partners were vulnerable to lower restedness, especially when they reported lower sleep duration or were in less supportive environments. Such disparities could underlie related disparities in health, as sleep health is predictive of health outcomes. Future research is needed to explore the role of sleep in explaining variation in health outcomes among sexual minority women.

So Tired: Predictive Utility of Baseline Sleep Screening in a Longitudinal Observational Survey Cohort of First-Year Residents

BACKGROUND

Sleep impairment is highly prevalent among resident physicians and is associated with both adverse patient outcomes and poor resident mental and physical health. Risk factors for sleep problems during residency are less clear, and no screening model exists to identify residents at risk for sleep impairment.

OBJECTIVE

The objective of this study was to assess change in resident sleep during training and to evaluate utility of baseline sleep screening in predicting future sleep impairment.

DESIGN

This is a prospective observational repeated-measures survey study.

PARTICIPANTS

The participants comprised PGY-1 residents across multiple specialties at Partners HealthCare hospitals.

MAIN MEASURES

Main measures used for this study were demographic queries and two validated scales: the Pittsburgh Sleep Quality Index (PSQI), measuring sleep quality, and the Epworth Sleepiness Scale (ESS), measuring excessive daytime sleepiness.

KEY RESULTS

Two hundred eighty-one PGY-1 residents completed surveys at residency orientation, and 153 (54%) completed matched surveys 9 months later. Mean nightly sleep time decreased from 7.6 to 6.5 hours (p < 0.001). Mean PSQI score increased from 3.6 to 5.2 (p < 0.001), and mean ESS score increased from 7.2 to 10.4 (p < 0.001). The proportion of residents exceeding the scales' clinical cutoffs increased over time from 15 to 40% on the PSQI (p < 0.001) and from 26 to 59% on the ESS (p < 0.001). Baseline normal sleep was not protective: 68% of residents with normal scores on both scales at baseline exceeded the clinical cutoff on at least one scale at follow-up. Greater age and fewer children increased follow-up PSQI score (p < 0.001) but not ESS score.

CONCLUSIONS

During PGY-1 training, residents experience worsening sleep duration, quality of sleep, and daytime sleepiness. Residents with baseline impaired sleep tend to remain impaired. Moreover, many residents with baseline normal sleep experience sleep deterioration over time. Sleep screening at residency orientation may identify some, but not all, residents who will experience sleep impairment during training.

Insomnia with objective short sleep duration and risk of incident cardiovascular disease and all-cause mortality: Sleep Heart Health Study

Study Objectives

To quantify the association between insomnia or poor sleep with objective short sleep duration and incident cardiovascular disease (CVD) and mortality in the general population.

Methods

We conducted a time-to-event analysis of Sleep Heart Health Study data. Questionnaires and at-home polysomnography (PSG) were performed between 1994 and 1998. Participants were followed for a median of 11.4 years (Q1-Q3, 8.8-12.4 years) until death or last contact. The primary exposure was insomnia or poor sleep with short sleep defined as follows: difficulty falling asleep, difficulty returning to sleep, early morning awakenings, or sleeping pill use, 16-30 nights per month; and total sleep of <6 hr on PSG. We used proportional hazard models to estimate the association between insomnia or poor sleep with short sleep and CVD, as well as all-cause mortality.

Results

Among 4994 participants (mean age: 64.0 ± 11.1 years), 14.1 per cent reported insomnia or poor sleep, of which 50.3 per cent slept <6 hr. Among 4437 CVD-free participants at baseline, we observed 818 incident CVD events. After propensity adjustment, there was a 29 per cent higher risk of incident CVD in the insomnia or poor sleep with short sleep group compared with the reference group (HR: 1.29, 95% CI: 1.00, 1.66), but neither the insomnia or poor sleep only nor short sleep only groups were associated with higher incident CVD. Insomnia or poor sleep with objective short sleep was not associated with all-cause mortality (HR: 1.07, 95% CI: 0.86, 1.33).

Conclusions

Insomnia or poor sleep with PSG-short sleep was associated with higher risk of incident CVD. Future studies should evaluate the impact of interventions to improve insomnia with PSG-short sleep on CVD.

Assessing sleep health in a European population: Results of the Catalan Health Survey 2015

Objective

To describe the overall sleep health of the Catalan population using data from the 2015 Catalan Health Survey and to compare the performance of two sleep health indicators: sleep duration and a 5-dimension sleep scale (SATED).

Methods

Multistage probability sampling representative of the non-institutionalized population aged 15 or more years, stratified by age, gender and municipality size, was used, excluding nightshift-workers. A total of 4385 surveys were included in the analyses. Associations between sleep health and the number of reported chronic diseases were assessed using non-parametric smoothed splines. Differences in the predictive ability of age-adjusted logistic regression models of self-rated health status were assessed. Multinomial logistic regression models were used to assess SATED determinants.

Results

Overall mean (SD) sleep duration was 7.18 (1.16) hours; and SATED score 7.91 (2.17) (range 0–10), lower (worse) scores were associated with increasing age and female sex. Alertness and efficiency were the most frequently impaired dimensions across age groups. SATED performed better than sleep duration when assessing self-rated health status (area under the curve = 0.856 vs. 0.798; p-value <0.001), and had a linear relationship with the number of reported chronic diseases, while the sleep duration relationship was u-shaped.

Conclusions

Sleep health in Catalonia is associated with age and gender. SATED has some advantaged compared to sleep duration assessment, as it relates linearly to health indicators, has a stronger association with self-rated health status, and provides a more comprehensive assessment of sleep health. Therefore, the inclusion of multi-dimensional sleep health assessment tools in national surveys should be considered.

Self-reported Sleep Duration and Subclinical Atherosclerosis in a General Population of Japanese Men

Aim: There are few data regarding associations between sleep duration and subclinical atherosclerosis in Japan. The aim of this study was to evaluate associations of self-reported sleep duration with calcification in the coronary arteries (CAC) and carotid intima media thickness (IMT) in Japanese men.

Methods: This was a cross-sectional survey of 1093 randomly selected men from Kusatsu City, Japan. Average sleep duration on weekdays was estimated through questionnaire; CAC by computed tomography; and carotid IMT by ultrasonography.

Results: The prevalence of CAC was 50.0% for participants with sleep duration < 5.5 h, 43.9% with 5.5–6.4 h, 50.0% with 6.5–7.4 h, 49.3% with 7.5–8.4 h, and 62.5% with ≥ 8.5 h. In univariate analysis, participants with sleep duration ≥ 8.5 h had significantly higher prevalence of CAC than those with 6.5–7.4 h (p = 0.043). After adjustment for age and other risk factors, however, the association was not significant (p = 0.776). The average IMT was 0.85 mm for participants with sleep duration < 5.5 h, 0.83 mm with 5.5–6.4 h, 0.85 mm with 6.5–7.4 h, 0.88 mm with 7.5–8.4 h, and 0.90 mm with ≥ 8.5 h. None of the differences in IMT observed in crude or multivariable-adjusted analyses was significant (all p > 0.1).

Conclusion: Self-reported sleep duration was not associated with increased CAC or carotid IMT in a general population of Japanese men.

Sleep Quality, Sleep Duration, and the Risk of Coronary Heart Disease: A Prospective Cohort Study With 60,586 Adults

STUDY OBJECTIVES

There is limited information on the relationship between risk of cardiovascular disease and the joint effects of sleep quality and sleep duration, especially from large, prospective, cohort studies. This study is to prospectively investigate the joint effects of sleep quality and sleep duration on the development of coronary heart disease.

METHODS

This study examined 60,586 adults aged 40 years or older. A self-administered questionnaire was used to collect information on sleep quality and sleep duration as well as a wide range of potential confounders. Events of coronary heart disease were self-reported in subsequent medical examinations. Two types of Sleep Score (multiplicative and additive) were constructed to reflect the participants' sleep profiles, considering both sleep quality and sleep duration. The Cox regression model was used to estimate the hazard ratio (HR) and the 95% confidence interval (CI).

RESULTS

A total of 2,740 participants (4.5%) reported new events of coronary heart disease at follow-up. For sleep duration, participants in the group of < 6 h/d was significantly associated with an increased risk of coronary heart disease (HR: 1.13, 95% CI: 1.04-1.23). However, the association in the participants with long sleep duration (> 8 h/d) did not reach statistical significance (HR: 1.11, 95% CI: 0.98-1.26). For sleep quality, both dreamy sleep (HR: 1.21, 95% CI: 1.10-1.32) and difficult to fall asleep/use of sleeping pills or drugs (HR: 1.40, 95% CI: 1.25-1.56) were associated with an increased risk of the disease. Participants in the lowest quartile of multiplicative Sleep Score (HR: 1.31, 95% CI: 1.16-1.47) and of additive sleep score (HR: 1.31, 95% CI: 1.16-1.47) were associated with increased risk of coronary heart disease compared with those in the highest quartile.

CONCLUSIONS

Both short sleep duration and poor sleep quality are associated with the risk of coronary heart disease. The association for long sleep duration does not reach statistical significance. Lower Sleep Score (poorer sleep profile) increases the risk of coronary heart disease, suggesting the importance of considering sleep duration and sleep quality together when developing strategies to improve sleep for cardiovascular disease prevention.

Observed Relationship Behaviors and Sleep in Military Veterans and Their Partners

BACKGROUND

Emerging research has begun to examine associations between relationship functioning and sleep. However, these studies have largely relied on self-reported evaluations of relationships and/or of sleep, which may be vulnerable to bias.

PURPOSE

The purpose of the study was to examine associations between relationship functioning and sleep in military couples. This is the first research to examine associations between observed relationship behaviors and subjective and polysomnographically measured sleep in a sample at-risk for both sleep and relationship problems.

METHODS

The sample included 35 military veterans and their spouses/partners. Marital functioning was coded from a videotaped conflict interaction. Analyses focused on behavioral codes of hostility and relationship-enhancing attributions. Sleep was assessed via self-report and in-home polysomnography.

RESULTS

Greater hostility was associated with poorer sleep efficiency for oneself (b = -0.195, p = .013). In contrast, greater relationship-enhancing attributions were associated with higher percentages of stage N3 sleep (b = 0.239, p = .028). Partners' hostility was also positively associated with higher percentages of stage N3 sleep (b = 0.272, p = .010). Neither hostility nor relationship-enhancing attributions was associated with self-reported sleep quality, percentage of REM sleep, or total sleep time.

CONCLUSIONS

Both partners' positive and negative behaviors during conflict interactions were related to sleep quality. These findings highlight the role that effective communication and conflict resolution skills may play in shaping not only the marital health of veterans and their spouses but also the physical health of both partners as well. Understanding the links between relationship functioning and sleep may be important targets of intervention in the aftermath of war.

The effect of sleep duration and sleep quality on hypertension in middle-aged and older Chinese: the Dongfeng-Tongji Cohort Study

OBJECTIVE

To examine the independent and combined associations of sleep duration and sleep quality with hypertension in a middle-aged and older Chinese population.

METHODS

We included 21,912 individuals aged 62.2 years at baseline from September 2008 to June 2010, and they were followed until October 2013. Sleep duration was self-reported and sleep quality was evaluated with questions designed according to the Pittsburgh Sleep Quality Index. Hypertension was defined as blood pressure ≥140/90 mmHg, or self-reported physician diagnosis of hypertension, or self-reported current use of antihypertensive medication.

RESULTS

In the cross-sectional analyses, the odds ratio of hypertension prevalence was significantly elevated (OR = 1.13, 95% CI = 1.03-1.24) in those who slept less than 7 h after adjusting for sex, age, body mass index, midday napping, cigarette smoking and sleep quality. It was particularly evident among males (OR = 1.19, 95% CI = 1.01-1.40) and individuals who were thin (OR = 2.00, 95% CI = 1.01-3.93) with full adjustment. The association was also found for sleep duration of 9∼<10 h after adjusting various covariates (OR = 1.14, 95% CI = 1.04-1.27). In addition, impaired sleep quality was only associated with hypertension in obese individuals (OR = 1.25, 95% CI = 1.02-1.50), not in other subgroups. However, no significant association was detected in any category of sleep duration or sleep quality in all models in the prospective analyses, and the results remained unchanged in the subgroup analyses of sex, age and body mass index.

CONCLUSIONS

The results of this study provide limited support for association of sleep duration and sleep quality with hypertension in middle-aged and older Chinese. Further studies are needed to confirm the results.

Sleep in adolescents and young adults

Sleep has an important role in maintaining health and wellbeing; this relationship is becoming increasingly recognised for adolescents and young adults. Many physicians will encounter young people who present with complaints or conditions that have some relation to poor sleep. This review article looks at why sleep matters within this population group, how it can impact on longer term health consequences and discusses some tools to help enable the clinician to evaluate and address sleep within clinical practice.

Sleep and Cardio-Metabolic Disease

PURPOSE OF REVIEW

This review summarises and discusses the epidemiological evidence suggesting a causal relationship between sleep duration and cardio-metabolic risk and outcomes in population.

RECENT FINDINGS

Sleep duration is affected by a variety of cultural, social, psychological, behavioural, pathophysiological and environmental influences. Changes in modern society-like longer working hours, more shift-work, 24/7 availability of commodities and 24-h global connectivity-have been associated with a gradual reduction in sleep duration and sleeping patterns across westernised populations. We review the evidence of an association between sleep disturbances and the development of cardio-metabolic risk and disease and discuss the implications for causality of these associations. Prolonged curtailment of sleep duration is a risk factor for the development of obesity, diabetes, hypertension, heart disease and stroke and may contribute, in the long-term, to premature death.

Relationship of Sleep Duration With All-Cause Mortality and Cardiovascular Events: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies

Background

Effects of extreme sleep duration on risk of mortality and cardiovascular outcomes remain controversial. We aimed to quantify the dose‐response relationships of sleep duration with risk of all‐cause mortality, total cardiovascular disease, coronary heart disease, and stroke.

Methods and Results

PubMed and Embase were systematically searched for prospective cohort studies published before December 1, 2016, that examined the associations between sleep duration and at least 1 of the 4 outcomes in generally healthy populations. U‐shaped associations were indicated between sleep duration and risk of all outcomes, with the lowest risk observed for ≈7‐hour sleep duration per day, which was varied little by sex. For all‐cause mortality, when sleep duration was <7 hours per day, the pooled relative risk (RR) was 1.06 (95% CI, 1.04–1.07) per 1‐hour reduction; when sleep duration was >7 hours per day, the pooled RR was 1.13 (95% CI, 1.11–1.15) per 1‐hour increment. For total cardiovascular disease, the pooled RR was 1.06 (95% CI, 1.03–1.08) per 1‐hour reduction and 1.12 (95% CI, 1.08–1.16) per 1‐hour increment of sleep duration. For coronary heart disease, the pooled RR was 1.07 (95% CI, 1.03–1.12) per 1‐hour reduction and 1.05 (95% CI, 1.00–1.10) per 1‐hour increment of sleep duration. For stroke, the pooled RR was 1.05 (95% CI, 1.01–1.09) per 1‐hour reduction and 1.18 (95% CI, 1.14–1.21) per 1‐hour increment of sleep duration.

Conclusions

Our findings indicate that both short and long sleep duration is associated with an increased risk of all‐cause mortality and cardiovascular events.

Characterizing sleeping habits and disturbances among Saudi adults

Objectives

To characterize sleeping habits, assess sleep disturbance prevalence, and identify associated factors among Saudi adults.

Methods

A total of 1720 adults were approached for this observational cross-sectional study between October 2014 and March 2015. The study took place in Riyadh, the capital of Saudi Arabia. We used a questionnaire to describe sleeping characteristics in relation to existing chronic diseases, smoking status, obesity, daily performance and sociodemographic variables.

Results

The response rate was 79.6% (1369 participants), 61.6% have or may have sleeping disturbances of which 18.6% claimed either slowed or stopped breathing during sleep. Women reported a higher prevalence of sleep disturbances (65.2%). Feeling tired was significantly associated with sleep disturbance (49% versus 19.7%) (p<0.001). Approximately 78.4% of those with sleep disturbance significantly believed that their ability to perform daily tasks is affected (p=0.005). Moreover, smoking and obesity were significantly associated with sleep disturbances (p<0.01). Participants with asthma, hypertension, chronic heart disease, and diabetes mellitus reported significantly more sleeping disturbance (p=0.016 to p=0.001).

Conclusions

Sleep disturbances are associated with obesity, smoking, chronic health conditions, and lower performance among Saudi adults.

Associations Between Sleep Habits and Dysglycemia in Adults in the United States: A Cross-Sectional Analysis

OBJECTIVES

To examine the independent and joint associations between sleep duration and quality with glycated hemoglobin (A1C) levels and dysglycemia in non-institutionalized adults living in the United States.

METHODS

Data from the United States National Health and Nutrition Examination Survey (2005-2008) were used (N=9478; ≥20 years). Information on sleep quantity and quality were derived from the Sleep Disorders Questionnaire and used to classify sleep quality as good, fair, poor, or very poor.

RESULTS

Overall, sleep quantity and quality were related to A1C levels in our unadjusted models. In general, a U-shaped relationship between sleep quantity and A1C levels was observed. Compared to those who slept for 7 to 8 hours per night, sleeping for 4 hours or fewer was associated with higher A1C levels (mean, 95% CI; 5.49%, 5.45 to 5.53 vs. 5.69%, 5.60 to 5.77; p<0.05), whereas only those reporting good and very poor sleep quality had higher A1C levels than poor sleepers (mean, 95% CI: 5.63%, 5.57 to 5.69; 5.56%, 5.52 to 5.60 vs. 5.46%, 5.42 to 5.50; p<0.05). The relationships among sleep duration and quality and the joint effects of sleep quality and quantity and dysglycemia were not significant after multivariable adjustment.

CONCLUSIONS

Between 7 and 8 hours of sleep and fair/poor sleep quality were associated with optimal A1C levels, while sleeping for fewer or more hours appeared to increase dysglycemia, without adjustment for covariates. These relationships were attenuated following multivariable adjustment. Future research is necessary to refine our understanding of the sleep/glycemic-control relationship to provide a context for the clinical significance of these findings for longer-term A1C control in adults with diabetes.

Association between insomnia and atrial fibrillation in a Chinese population: A cross-sectional study

BACKGROUND

Insomnia is the most prevalent sleep disorder; however, little research has explored the link between insomnia and atrial fibrillation (AF).

HYPOTHESIS

Insomnia is associated with increased risk of AF in a Chinese population.

METHODS

A total of 8371 Chinese participants (4314 males; mean age, 42.4 ± 13.1 years) were enrolled in this cross-sectional study to investigate the association between insomnia and AF. AF was assessed in a standard supine resting position with a 10-s 12-lead electrocardiograph (ECG) or by self-reported history. Insomnia was assessed using the Athens Insomnia Scale (AIS), and a score of ≥6 was regarded as having insomnia. The association between insomnia and AF was determined by logistic regression analysis.

RESULTS

Among the 8371 subjects, 1074 (12.8%) had different degrees of insomnia, and AF was observed in 50 subjects (0.60%). After adjusting for potential confounders, individuals with insomnia had moderately increased likelihood of suffering from AF compared with those without insomnia (odds ratio [OR]: 1.92, 95% confidence interval [CI]: 1.00-3.70, P = 0.05). After stratifying data by age, a significant positive association was found in those age <40 years (OR: 6.52, 95% CI: 1.64-25.83, P = 0.01), and a similar trend existed in males after stratifying by sex, although this relationship was not statistically significant (OR: 2.11, 95% CI: 0.92-4.83, P = 0.08).

CONCLUSIONS

Individuals with insomnia may have a higher risk of AF in the particular Chinese population assessed in this study. Age (<40 years) is a significant factor in the association between insomnia and AF.

Combined association of clinical and lifestyle factors with non-restorative sleep: The Nagahama Study

Background

Non-restorative sleep (NRS) was suggested to be associated with cardiovascular outcomes. However, causative factors for NRS have not been fully elucidated. This study aimed to clarify factors and their relationships with NRS to better understand the clinical and epidemiological implications of NRS and to develop a score that can objectively evaluate NRS status.

Methods

Study subjects consisted of 9,788 community residents (age 53.6 ± 13.4 y). Subjective NRS as well as possible clinical and lifestyle factors for NRS were investigated by questionnaires. Other clinical parameters were obtained from personal records of information obtained at the baseline examination.

Results

A total of 3,261 participants complained of NRS. Factors independently associated with subjective NRS were younger age (odds ratio = 1.43), use of a hypnotic drug (2.04), irregular sleep schedule (2.02), short sleep duration (<5 h, 11.7; 5–6 h, 4.81; 6–7 h, 2.40), frequent sleepiness (2.33), routine stress (4.63), no habitual exercise (1.61), nocturia symptoms (1.43), symptoms of gastroesophageal reflux disease (1.44), and depression (1.46) (all P <0.001). The NRS score comprised of these 10 factors was linearly associated with the frequency of subjective NRS (P_trend <0.001). Frequency of individuals with a high NRS score was greater in women (52.3%) than in men (42.1%, P<0.001), while no clear association was observed with common risk factors for cardiovascular diseases.

Conclusions

NRS was a phenomenon representing various clinical and lifestyle features. Careful attention should be paid to individuals with a high NRS score who might be at risk for mental fatigue and have unfavorable lifestyle factors.