Cross-sectional versus prospective associations of sleep duration with changes in relative weight and body fat distribution: the Whitehall II Study

Examining mental health and autonomic function as putative mediators of the relationship between sleep and trajectories of cognitive function: findings from the Irish longitudinal study on ageing (TILDA)

OBJECTIVES

This study investigates the mediating roles of autonomic function and mental health in the association between sleep and cognitive decline in adults aged 50 and above.

METHOD

A total of 2,697 participants with observations on sleep and mediators at baseline and repeated measures of cognitive function (MMSE) were included. Clusters of individuals with similar cognitive trajectories (high-stable, mid-stable and low-declining) were identified. Multinomial logistic regressions were used to estimate the likelihood of membership to each trajectory group based on sleep duration and disturbance. Finally, mediation analysis tested potential mediating effects of autonomic function and mental health underpinning the sleep-cognition relationship.

RESULTS

Short (p = .028), long (p =.019), and disturbed sleep (p =.008) increased the likelihood of a low-declining cognitive trajectory. Mental health measures fully attenuated relationships between cognitive decline and short or disturbed sleep but not long sleep. No autonomic function mediation was observed.

CONCLUSION

Older adults with short or disturbed sleep are at risk of cognitive decline due to poor mental health. Individuals with long sleep are also at risk, however, the acting pathways remain to be identified. These outcomes have clinical implications, potentially identifying intervention strategies targeting mental health and sleep as prophylactic measures against dementia.

Association of Short Sleep Duration and Obstructive Sleep Apnea with Central Obesity: A Retrospective Study Utilizing Anthropometric Measures

Background

Central obesity, as measured by examination instruments, has been shown to be associated with both OSA and short sleep duration. However, objective measurement tools like CT, MRI, and DXA are expensive, cause radiation exposure, and have limited availability, especially in resource-limited settings. Thus, this study aimed to demonstrate the relevance of Body Mass Index (BMI) and Waist-to-Height Ratio (WHtR) as surrogate indicators of visceral obesity in the assessment of OSA and short sleep duration. We also intend to evaluate whether WHtR, in combination with BMI, can be a suitable surrogate marker for visceral adiposity.

Methods

We recruited 333 adults with complete polysomnographic (PSG) records retrospectively. Logistic regression helped to assess the association of BMI and WHtR as surrogates for central adiposity with OSA and short sleep duration. Moreover, ROC curve analysis was conducted to evaluate the predictive ability of BMI and WHtR.

Results

Following the relevant adjustments, logistic regression analysis results showed that the combination of WHtR and BMI acting as central obesity surrogates was significantly associated with OSA and short sleep duration (p<0.05). According to univariate regression analysis, sleep latency and wake after sleep onset were independent predictors of the risk of central obesity in patients with short sleep duration and OSA. Additionally, ROC curve analysis demonstrated that the combination of BMI and WHtR provided a better assessment of central adiposity in patients with OSA and short sleep duration, compared to each measure alone.

Conclusion

BMI and WHtR are significantly associated with OSA and short sleep duration, and might serve as a potential surrogate marker for central obesity. Sleep latency and wake after sleep onset can independently predict the risk of central obesity in patients with short sleep time and OSA. Thus, larger prospective studies are needed to verify our findings.

Sleep Duration Alters Overfeeding-mediated Reduction in Insulin Sensitivity

CONTEXT

Weight gain and sleep restriction both reduce insulin sensitivity. However, it is not known if sleep duration alters glucose metabolism in response to overfeeding.

OBJECTIVE

To examine the effect of sleep duration on overfeeding-mediated alterations in carbohydrate metabolism and insulin sensitivity.

METHODS

Retrospective exploratory analysis of a longitudinal overfeeding study in healthy participants (n = 28, age: 26.9 ± 5.5 years, body mass index: 25.74 ± 2.45 kg/m2). After providing baseline study measures, participants were overfed 40% above weight maintenance calorie requirements for 8 weeks. Insulin sensitivity was determined by a 2-step hyperinsulinemic-euglycemic clamp. Baseline habitual sleep duration was estimated by accelerometry, and sleep groups were created based on median sleep duration (5.2 hours/night).

RESULTS

Overfeeding led to an average body weight gain of 7.3 ± .4 kg. Habitual sleep duration did not alter overfeeding-mediated body weight gain, fat gain, and fat distribution (all P > .15). Compared to participants with more sleep, fasting insulin (P = .01) and homeostatic model assessment for insulin resistance (P = .02) increased while fasting glucose remained unchanged (P = .68) with overfeeding in participants with shorter sleep duration. Glucose infusion rate during high insulin dose was reduced with overfeeding in participants with short sleep duration but not in participants with more sleep (P < .01).

CONCLUSION

Overfeeding mediated weight gain reduced liver, adipose, and whole-body insulin sensitivity prominently in individuals with short sleep duration but not in individuals with longer sleep duration. This suggests that promoting adequate sleep during short periods of overeating may prevent detrimental effects on glucose metabolism.

Association of sleep duration with Visceral Adiposity Index: a cross-sectional study based on the NHANES 2007-2018

OBJECTIVE

We aimed to assess the associations between sleep duration and Visceral Adiposity Index (VAI).

DESIGN

Cross-sectional study.

SETTING

The National Health and Nutrition Examination Survey (2007-2018).

PARTICIPANTS

A total 11 252 eligible participants who have complete information for sleep duration and VAI.

OUTCOME MEASURE

The VAI index, which is sex-specific and takes into consideration factors such as waist circumference, body mass index, high-density lipoprotein cholesterol and triglycerides, was calculated in accordance with prior research. Multiple linear regressions and subgroup analyses were employed to evaluate the connection between the duration of sleep and the VAI.

RESULTS

The mean sleep duration and VAI of included participants were 7.05 hours/day and 2.03, respectively. After adjusting for the sociodemographic, lifestyle and other covariates, short sleep was significantly linked to increased VAI (β=0.15, 95% CI 0.01 to 0.28) in relation to middle sleep duration, whereas no significant association was found between long sleep duration and VAI. An L-shaped relationship was observed between sleep duration and VAI. When sleep duration was less than 7.5 hours/day, a negative association between sleep duration and VAI was obvious. However, when sleep duration was >7.5 hours/day, VAI was increased with a longer sleep duration, although it was not significant.

CONCLUSIONS

An L-shaped relationship was observed between sleep duration and VAI, with insufficient sleep, being independently linked to a higher VAI. This implies that sleep deprivation might be associated with visceral adipose distribution and disfunction.

The Importance of Sleep in Overcoming Childhood Obesity and Reshaping Epigenetics

The development of childhood obesity is a complex process influenced by a combination of genetic predisposition and environmental factors, such as sleep, diet, physical activity, and socioeconomic status. Long-term solutions for decreasing the risk of childhood obesity remain elusive, despite significant advancements in promoting health and well-being in school and at home. Challenges persist in areas such as adherence to interventions, addressing underlying social determinants, and individual differences in response to treatment. Over the last decade, there has been significant progress in epigenetics, along with increased curiosity in gaining insights into how sleep and lifestyle decisions impact an individual's health. Epigenetic modifications affect the expression of genes without causing changes to the fundamental DNA sequence. In recent years, numerous research studies have explored the correlation between sleep and the epigenome, giving a better understanding of DNA methylation, histone modification, and non-coding RNAs. Although significant findings have been made about the influence of sleep on epigenetics, a notable gap exists in the literature concerning sleep-related genes specifically associated with childhood obesity. Consequently, it is crucial to delve deeper into this area to enhance our understanding. Therefore, this review primarily focuses on the connection between sleep patterns and epigenetic modifications in genes related to childhood obesity. Exploring the interplay between sleep, epigenetics, and childhood obesity can potentially contribute to improved overall health outcomes. This comprehensive review encompasses studies focusing on sleep-related genes linked to obesity.

The effects of sleep disruption on metabolism, hunger, and satiety, and the influence of psychosocial stress and exercise: A narrative review

Sleep deficiency is a ubiquitous phenomenon among Americans. In fact, in the United States, ∼78% of teens and 35% of adults currently get less sleep than recommended for their age-group, and the quality of sleep appears to be getting worse for many. The consequences of sleep disruption manifest in a myriad of ways, including insulin resistance and disrupted nutrient metabolism, dysregulation of hunger and satiety, and potentially increased body weight and adiposity. Consequently, inadequate sleep is related to an increased risk of various cardiometabolic diseases, including obesity, diabetes, and heart disease. Exercise has the potential to be an effective therapeutic to counteract the deleterious effects of sleep disruption listed above, whereas chronic psychosocial stress may causally promote sleep disruption and cardiometabolic risk. Here, we provide a narrative review of the current evidence on the consequences of short sleep duration and poor sleep quality on substrate metabolism, circulating appetite hormones, hunger and satiety, and weight gain. Secondly, we provide a brief overview of chronic psychosocial stress and its impact on sleep and metabolic health. Finally, we summarise the current evidence regarding the ability of exercise to counteract the adverse metabolic health effects of sleep disruption. Throughout the review, we highlight areas where additional interrogation and future exploration are necessary.

The Relationship between Knowledge, Dietary Supplementation, and Sleep Quality in Young Adults after the COVID-19 Pandemic

INTRODUCTION

Sleep is one of the most important factors affecting the quality of life. More than 50% of Polish adults have sleeping disorders, and young adults are the ones particularly vulnerable to this. This is why the analysis of the predictors of sleep quality, such as sleep hygiene knowledge and dietary knowledge, in young adults is a very important topic, especially after the COVID-19 pandemic, which may have affected sleeping habits.

MATERIAL AND METHODS

402 young adults (mean age 28.12 ± 6.08 years old) were enrolled in the study during the COVID-19 pandemic. Sleep quality was assessed with the Pittsburgh Sleep Quality Questionnaire, while dietary knowledge and sleep hygiene knowledge were assessed with dedicated questionnaires. The participants were also asked about the use of specific dietary supplements.

RESULTS

The analysis showed that sleep hygiene knowledge was significantly associated with sleep length (R = -0.17, p = 0.003) and overall sleep quality (R = -0.17, p = 0.005), while dietary knowledge significantly correlated with time to fall asleep (R = -0.12, p = 0.026). The regression analysis revealed that sleep hygiene knowledge was a significant negative predictor of sleep quality impairment (β = -0.13, p = 0.028). Significant results were also obtained for the use of supplements (β = -0.20; p = 0.001) and the use of medications (β = -0.32, p = 0.001), which were negative predictors of sleep quality impairment.

CONCLUSIONS

This study showed that increased sleep hygiene knowledge promoted improved sleep length and overall sleep quality. In addition, dietary knowledge significantly correlated with time to fall asleep. On the other hand, decreased sleep quality was observed in participants who used medications or dietary supplements.

[Sleep quality, emotional and behavioral disturbances, and eating behavior in adolescents with obesity: a network analysis-based model]

OBJECTIVE

To attempt to identify persistent associations between sleep quality, symptoms of emotional and behavioral disturbances, and characteristics of eating behavior in obese adolescents based on a network analysis.

MATERIAL AND METHODS

The study included 194 adolescents, aged 12-17 years (76 girls, 118 boys), with a confirmed diagnosis of obesity due to excess calories (ICD-10 code E66.0). Sleep quality was studied on the basis of the Adolescent Sleep Wake Scale (ASWS), emotional and behavioral disturbances were assessed with the Achenbach Youth Self-Report for Ages 11-18 (YSR), eating behavior - with the Dutch Eating Behavior Questionnaire (DEBQ). Network analysis was used to identify the most significant and stable associations between the studied indicators.

RESULTS

The association of poor sleep quality with manifestations of disinhibited behavior in the form of violations of the rules of behavior, aggressiveness, and impaired attention was revealed. Positive correlations between the manifestations of disinhibited behavior (primarily, rule-breaking behavior) and emotional eating behavior, which, in turn, had a positive relationship with external and a negative relationship with restrictive eating behavior, were noted. The disinhibited adolescent behavior is linked with uncontrolled food intake, which can contribute to the development of obesity.

CONCLUSION

Impaired sleep quality, symptoms of emotional and behavioral disorders, and eating disorders in obese adolescents present a stable and specific clinical pattern that should be taken into account when justifying therapy.

The impact of social rhythm and sleep disruptions on waist circumference after job loss: A prospective 18-month study

OBJECTIVE

This study prospectively examined change in waist circumference (WC) as a function of daily social rhythms and sleep in the aftermath of involuntary job loss. It was hypothesized that disrupted social rhythms and fragmented/short sleep after job loss would independently predict gains in WC over 18 months and that resiliency to WC gain would be conferred by the converse.

METHODS

Eligible participants (n = 191) completed six visits that included standardized measurements of WC. At the baseline visit, participants completed the social rhythm metric and daily sleep diary and wore an actigraph on their nondominant wrist each day for a period of 2 weeks.

RESULTS

When controlling for obesity and other covariates, WC trajectories decreased for individuals with more consistent social rhythms, more activities in their sdiocial rhythms, and higher sleep quality after job loss. WC trajectories did not change for individuals with lower scores on these indicators.

CONCLUSIONS

The frequency and consistency of social rhythms after job loss play a key role in WC loss. These findings support the implementation of social rhythm interventions after job loss, a potentially sensitive time for the establishment of new daily routines that have an impact on metabolic health.

Effects of Experimental Sleep Restriction on Energy Intake, Energy Expenditure, and Visceral Obesity

BACKGROUND

Although the consequences of sleep deficiency for obesity risk are increasingly apparent, experimental evidence is limited and there are no studies on body fat distribution.

OBJECTIVES

The purpose of this study was to investigate the effects of experimentally-induced sleep curtailment in the setting of free access to food on energy intake, energy expenditure, and regional body composition.

METHODS

Twelve healthy, nonobese individuals (9 males, age range 19 to 39 years) completed a randomized, controlled, crossover, 21-day inpatient study comprising 4 days of acclimation, 14 days of experimental sleep restriction (4 hour sleep opportunity) or control sleep (9 hour sleep opportunity), and a 3-day recovery segment. Repeated measures of energy intake, energy expenditure, body weight, body composition, fat distribution and circulating biomarkers were acquired.

RESULTS

With sleep restriction vs control, participants consumed more calories (P = 0.015), increasing protein (P = 0.050) and fat intake (P = 0.046). Energy expenditure was unchanged (all P > 0.16). Participants gained significantly more weight when exposed to experimental sleep restriction than during control sleep (P = 0.008). While changes in total body fat did not differ between conditions (P = 0.710), total abdominal fat increased only during sleep restriction (P = 0.011), with significant increases evident in both subcutaneous and visceral abdominal fat depots (P = 0.047 and P = 0.042, respectively).

CONCLUSIONS

Sleep restriction combined with ad libitum food promotes excess energy intake without varying energy expenditure. Weight gain and particularly central accumulation of fat indicate that sleep loss predisposes to abdominal visceral obesity. (Sleep Restriction and Obesity; NCT01580761).

Is self-reported short sleep duration associated with obesity? A systematic review and meta-analysis of cohort studies

CONTEXT

A possible association between self-reported short sleep duration and risk of obesity has been studied.

OBJECTIVE

To analyze the association between sleep duration and obesity.

METHODS

The LILACS, Medline, Central, Embase, and OpenGrey databases were searched from inception until July 2020. Two authors screened the studies independently according to the PECO strategy, as follows: participants: > 18 years old; exposure: short sleep duration; control: regular sleep; outcome: obesity). Only cohort studies were included. A total of 3286 studies were retrieved with the search strategy, but only 36 were included. Disagreements were resolved by a third author. The quality of studies was assessed with Newcastle-Ottawa Quality Assessment Form for Cohort Studies. The certainty of the evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation.

RESULTS

Thirty-six studies were included, and 22 contributed quantitative data. Most of the studies (n = 27) assessed sleep by self-report. The meta-analysis showed a significant association between self-reported short sleep and development of obesity, and the chances of developing obesity increased when self-reported sleep duration decreased.

CONCLUSIONS

Self-reported short sleep was significantly associated with a higher incidence of obesity, with moderate quality of evidence.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42019130143.

Physical activity and sleep quality correlations with anthropometric measurements in young adults

OBJECTIVE

This cross-sectional study examined correlations between physical activity and anthropometrics as well as sleep quality and anthropometrics.

PARTICIPANTS

College students (n = 85) with average age 25.6 ± 5.4 years.

METHODS

Participants received full-body dual-energy x-ray absorptiometry scans and completed validated surveys: Habitual Physical Activity questionnaire, Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale.

RESULTS

Males reported more sports-related physical activity than females (p = 0.041). Physical activity indices and percent body fat were inversely correlated (total ⍴ = -0.320, p < 0.001; sport β = -0.378, p = 0.003). Participants had poor overall sleep quality (PSQI = 6.19 ± 2.99). The PSQI sleep quality index: disturbance was directly correlated with body mass index (BMI) (β = 0.328, p = 0.007).

CONCLUSION

Health interventions on college campuses should promote more physical activity and better quality sleep as these factors were related to improved body anthropometrics and potentially reduced chronic disease risk.

Genetics of Sleep and Insights into Its Relationship with Obesity

Considerable recent advancements in elucidating the genetic architecture of sleep traits and sleep disorders may provide insight into the relationship between sleep and obesity. Despite the considerable involvement of the circadian clock in sleep and metabolism, few shared genes, including FTO, were implicated in genome-wide association studies (GWASs) of sleep and obesity. Polygenic scores composed of signals from GWASs of sleep traits show largely null associations with obesity, suggesting lead variants are unique to sleep. Modest genome-wide genetic correlations are observed between many sleep traits and obesity and are largest for snoring.Notably, U-shaped positive genetic correlations with body mass index (BMI) exist for both short and long sleep durations. Findings from Mendelian randomization suggest robust causal effects of insomnia on higher BMI and, conversely, of higher BMI on snoring and daytime sleepiness. Bidirectional effects between sleep duration and daytime napping with obesity may also exist. Limited gene-sleep interaction studies suggest that achieving favorable sleep, as part of a healthy lifestyle, may attenuate genetic predisposition to obesity, but whether these improvements produce clinically meaningful reductions in obesity risk remains unclear. Investigations of the genetic link between sleep and obesity for sleep disorders other than insomnia and in populations of non-European ancestry are currently limited. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Associations of sleep duration with physical fitness performance and self-perception of health: a cross-sectional study of Taiwanese adults aged 23-45

Background

The relationship between sleep duration and physical fitness is one aspect of sleep health. Potential factors associated with sleep duration interfere with physical fitness performance, but the impact trends on physical fitness indicators remain unclear.

Methods

This study examined associations between sleep duration and physical fitness among young to middle-aged adults in Taiwan. A total of 42,781 Taiwanese adults aged 23–45 participated in the National Physical Fitness Examination Survey 2013 (NPFES-2013) in Taiwan between October 2013 and March 2014. A standardized structural questionnaire was used to record participants’ sleep duration, which was stratified as short (< 6 h/day (h/d)), moderate (6–7 h/d; 7–8 h/d; 8-9 h), and long (≥ 9 h/d) sleep duration groups. Physical fitness was assessed based on four components: body composition (body mass index [BMI], waist-to-height ratio [WHtR], and waist-to-hip ratio [WHR]), muscle strength and endurance (1-min bent-leg sit-up test [BS]), flexibility (sit-and-reach test [SR]), and cardiorespiratory endurance index (3-min step test [CEI]).

Results

By using analysis of covariance (ANCOVA), after sex grouping and age adjustment, we observed that sleep duration was significantly associated with obesity, functional fitness, and self-perception of health. The sleep duration for low obesity-related values (BMI, WHtR, and WHR) for men was 7–9 h/d, and that for women was 7–8 h/d. Sleeping more than 8 h/d showed poor functional fitness performances (BS and SR). For both sexes, sleep duration of 8–9 h/d was the optimal sleep duration for self-perceptions of health.

Conclusions

Our research found that there were wide and different associations of sleep duration with physical fitness and self-perception of health among Taiwanese adults aged 23–45, and there were differences in these associated manifestations between men and women. This study could be of great importance in regional public health management in Taiwan, and provide inspirations for clinical research on physical fitness.

The association between sleep duration and excess body weight of the American adult population: a cross-sectional study of the national health and nutrition examination survey 2015-2016

BACKGROUND

We intend to explore whether sleep duration is associated with overweight and obesity among the adult American population. Furthermore, we stratified the study population by age and sex in the subgroup analysis to investigate the potential disparities between adults and older adults, and men and women.

METHODS

In total, 2459 individuals from the 2015-2016 National Health and Nutrition Examination Survey cycle were included for analysis in this study. Sleep duration was assessed by the Sleep Disorders Questionnaire. Classification of the short-sleep, normal-sleep, and long-sleep group was based on the recommendation of the National Sleep Foundation. Bodyweight was measured during the physical examination. Multivariate logistic regression models were implemented.

RESULTS

We observed a significantly higher overweight incidence in the short-sleep group compared to the normal-sleep group (OR = 1.825, 95%CI: 1.251-2.661, P = 0.004). Short-sleep (OR = 1.832, 95%CI: 1.215-2.762, P = 0.007) duration and long-sleep duration (OR = 1.370, 95%CI: 1.043-1.800, P = 0.027) were associated with higher prevalence of obesity. When stratified by age, short-sleep also increased the overweight and obese incidence 1.951 and 1.475 times in the adult group. In the sex-stratified subgroup analysis, the short-sleep group showed 2.49 times higher overweight incidence among females. The prevalence of obesity was 2.59 times higher in the short-sleep group and 1.698 times higher in the long-sleep group in the female population.

CONCLUSIONS

Sleep duration is associated with the occurrence of overweight and obesity, with sleep duration less than 7 h increase the overweight and obesity rate nearly 2 folds comparing to sleep 7-9 h.

Association between sleep duration and weight gain and incident overweight/obesity: longitudinal analyses from the China Health and Nutrition Survey

OBJECTIVE

To evaluate the association between sleep duration and weight gain and incident overweight/obesity in the population of China.

METHODS

Data were derived from the China Health and Nutrition Survey. Adult participants with baseline data of sleep duration and body mass index (BMI) and who received at least one follow-up evaluation were selected to analyze the association of sleep duration with weight gain (n = 12,871) and incident overweight/obesity (n = 7,752). Daily sleep duration was categorized into five groups: ≤ 6, 7, 8 (as reference), 9, and ≥ 10 h. The study outcomes were weight gain ≥ 5 kg and incident overweight/obesity (BMI ≥ 24 kg/m²).

RESULTS

Adjusted Cox proportional hazards models showed that only short sleep duration (≤ 6 h) significantly increased the risk of weight gain ≥ 5 kg (HR: 1.160, 95% CI: 1.005-1.339, p < 0.001) and incident overweight/obesity (HR: 1.403, 95% CI: 1.185-1.660, p < 0.001), whereas sleep duration 9 h was significantly associated with a lower risk of incident overweight/obesity (HR: 0.817, 95% CI: 0.700-0.953, p = 0.010). No significant correlation was found between long sleep duration (> 10 h) and the risk of weight gain ≥ 5 kg and incident overweight/obesity.

CONCLUSION

Short sleep duration is a risk factor for the development of weight gain ≥ 5 kg and incident overweight/obesity in Chinese adults, whereas long sleep duration had no effect on future obesity.

Insomnia and daytime sleepiness predict 20-year mortality in older male adults: data from a population-based study

Data regarding the possible relationship of insomnia and EDS with mortality are inconclusive. The aim of this study was to investigate the association between these sleep complaints and the risk of long-term (20 years) all-cause mortality in older adults. Between April 2000 and March 2001, 750 subjects aged 65 years and older, who resided in the seventh district of Udine, were recruited. Data on sociodemographic characteristics, past medical history, and pharmacological treatment were collected. Dementia was diagnosed using a comprehensive neurological and neuroradiological assessment. Older adults were interviewed by neuropsychologists trained in sleep disturbances in order to assess the presence of sleep complaints. Vital status was followed over 20 years until March 2020. Older male adults affected by insomnia and EDS were significantly more likely to die over the follow-up period. Indeed, males reporting poor sleep and daytime somnolence had a 60% and 48% higher chance of dying than subjects who were not affected by these sleep complaints, respectively. The HR was attenuated after adjusting for confounding variables among insomniacs, whereas that of somnolent men strengthened. Differently from men, insomnia and EDS did not have any impact on mortality in older women. In conclusion, older male adults affected by insomnia and EDS had a significant increased risk of mortality, which is independent of cancer, depression, dementia, cardiovascular diseases, and sleeping pill use.

Association of Sleep Duration and Overweight/Obesity among Children in China

To investigate the association of sleep duration with overweight and obesity among children aged 6 to 17 years in China, 2010–2012 data from the China National Nutrition and Health Surveillance (CNHHS) were analyzed. A total of 35,414 children were recruited in the survey. Body mass index (BMI) was converted into three categories: normal weight, overweight and obesity. In multinomial logistic regression model, sleep duration was divided into four groups: very short, short, recommended and long. In restricted cubic splines (RCS), sleep duration was examined as a continuous variable in relation to overweight and obesity. In the very short and short groups, sleep duration was a risk factor for obesity after adjusting for the potential impacts of age, gender, residence, family income, leisure sedentary behavior (SB) and leisure exercise, with OR (Odds Ratio) = 3.01 (95% CI (confidence interval): 2.19–4.15) and OR = 1.24 (95% CI: 1.14–1.35), respectively. The adjusted OR of overweight for short sleep duration relative to a recommended sleep duration was 1.17(95% CI: 1.09–1.26). No significant associations of very short sleep with overweight, of long sleep duration with overweight and obesity were found. The RCS curves between sleep duration and overweight and obesity were both inverted J-shaped. To conclude, the shorter the sleep duration, the higher the risk of overweight and obesity in children. Increasing sleep duration would have a positive effect on reducing overweight and obesity rates in Chinese children.

Association of Sleep Duration with Weight Gain and General and Central Obesity Risk in Chinese Adults: A Prospective Study

OBJECTIVE

Evidence on the association between sleep duration and obesity among adults is inconsistent. Prospective studies investigating the association in Chinese adults have been limited. This study aims to prospectively evaluate sleep duration in relation to subsequent weight gain and general and central obesity risk among Chinese adults.

METHODS

A total of 21,958 participants aged 30 to 79 years reported their daily sleep duration. Obesity indicators were objectively measured; then significant weight gain (≥ 5 kg) and general and central obesity were modeled as the outcome. Logistic regression models were used to estimate odds ratios and 95% CIs.

RESULTS

Average sleep duration was 7.5 hours at baseline. During 8.0 ± 0.8 years of follow-up, participants who reported sleeping ≤ 6 hours had higher risk for significant weight gain than those who slept 7 hours (multivariable-adjusted odds ratio: 1.13; 95% CI: 1.02-1.29). The association was stronger among those who were physically inactive at baseline (P = 0.04 for interaction). Short sleep duration was also associated with subsequent incident central obesity, with odds ratio of 1.13 (95% CI: 1.00-1.28), but not with incident general obesity (P = 0.31).

CONCLUSIONS

Compared with those who slept 7 hours per day, short sleepers had an increased risk of significant weight gain and central obesity.

Interrelationships among common predictors of cardiovascular diseases in patients of OSA: A large-scale observational study

BACKGROUND AND AIMS

The apolipoprotein B/apolipoprotein A-I (ApoB/ApoA-I) and insulin resistance has been recognized as common cardiovascular diseases (CVD) risk factors. However, whether they were biomarkers for 10-year CVD risk in obstructive sleep apnea (OSA) had been rarely studied. Besides, interrelationships between the ApoB/ApoA-I, insulin resistance and OSA remain unclear.

METHODS AND RESULTS

A total of 4010 subjects were finally included. Anthropometric, fasting biochemical, and polysomnographic parameters were collected. 10-year Framingham CVD risk score (FRS) was calculated for each subjects. The relationships between insulin resistance, OSA risk and the ApoB/ApoA-I was evaluated through logistic regressions analysis, restricted cubic spline (RCS) analysis and mediation analysis. ApoB/ApoA-I, HOMA-IR and AHI were all risk factors for high10-year CVD risk as assessed by FRS (odds ratios (OR) = 5.365, 1.094, 1.010, respectively, all P < 0.001)). The fully adjusted OR (95% confidence intervals) for both OSA [1 (reference), 1.308 (1.027-1.665), 1.517 (1.178-1.953), and 1.803 (1.371-2.372)] and insulin resistance [1 (reference), 1.457 (1.173-1.711), 1.701 (1.369-2.113), 2.051(1.645-2.558)] increased from the first to the fourth quartiles of the ApoB/ApoA-I. The RCS mapped a nonlinear dose-effect relationship between the ApoB/ApoA-I and risk of insulin resistance and OSA. Mediation analyses showed HOMA-IR explain 9.7%, 4.7% and 10.8% of the association between apnea-hypopnea index, oxygen desaturation index, micro-arousal index and ApoB/ApoA-I, respectively.

CONCLUSIONS

Our study revealed that ApoB/ApoA-I, insulin resistance and OSA were risk factors for CVD. Insulin resistance may serve as a potential mediator in OSA-related lipoprotein disorders and further increase CVD risk.

Sleep duration and body mass index: moderating effect of self-perceived stress and age. Results of a cross-sectional population-based study

PURPOSE

The objective of this analysis was to assess whether the association between sleep duration and BMI and between sleep duration and waist circumference is moderated by age and self-perceived stress.

METHODS

We analyzed data from 2034 participants enrolled in 2014 in the cross-sectional study Obesity in Romania Study-study of the prevalence of obesity and related risk factors in Romanian general population (ORO study).

RESULTS

Interaction between sleep duration, self-perceived stress and age, with BMI as dependent variable, was statistically significant after adjustment for demographic and lifestyle factors (p value for interaction 0.003). In participants without self-perceived stress, a linear negative association between sleep duration and BMI was observed only in those 18-39 years old (p = 0.049), with BMI decreasing in parallel with increased sleep duration. In participants with self-perceived stress, a U-shaped relationship was observed between BMI and sleep duration in those 40-64 years old, with higher BMI in those sleeping ≤ 6 h and ≥ 9 h/night compared to those sleeping > 6 and < 9 h/night (p = 0.002 and 0.005). Those ≥ 65 years old with self-perceived stress sleeping ≥ 9 h/night had a significantly higher BMI compared to those in other sleep duration categories (p = 0.041 vs. those sleeping ≤ 6 h/night and p = 0.013 vs. to those sleeping > 6 and < 9 h/night). No interaction between age, self-perceived stress and sleep duration, with waist circumference as dependent variable was observed.

CONCLUSIONS

In our sample, the association between sleep duration and BMI was moderated by self-perceived stress and age.

The Association Between Body Mass Index (BMI) and Sleep Duration: Where Are We after nearly Two Decades of Epidemiological Research?

Over the past twenty years we have seen a vast number of epidemiological studies emerge on the topic of obesity and sleep duration, with a focus on body mass index, as it is easy and cheap to measure and analyse. Such studies largely observe that cross-sectionally a higher BMI is associated with shorter sleep and that in longitudinal studies shorter sleep duration is associated with increases in BMI over time, but some research has found no relationship between the two. This narrative review is not exhaustive, but appraises the literature on sleep duration and BMI from perspectives that have previously been unexplored in a single paper. As such, I discuss research in these important areas: bidirectionality, objective vs. subjective sleep duration, how meaningful the effect sizes are and how we have begun to address causality in this area. From the evidence appraised in this review, it is clear that: (i) there is some modest evidence of a bidirectional relationship between BMI and sleep duration in both children and adults; (ii) objective measurements of sleep should be used where possible; (iii) it remains difficult to confirm whether the effect sizes are conclusively meaningful in a clinical setting, but at least in adults this so far seems unlikely; (iv) to date, there is no solid evidence that this relationship (in either direction) is in fact causal. In the near future, I would like to see triangulation of these findings and perhaps a move towards focusing on distinct aspects of the relationship between obesity and sleep that have not previously been addressed in detail, for various reasons.

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.

Long sleep duration predicts a higher risk of obesity in adults: a meta-analysis of prospective cohort studies

BACKGROUND

The connections between long sleep duration and obesity or weight gain warrant further examination. This meta-analysis aimed to evaluate whether long sleep duration was associated with the risk of obesity, weight gain, body mass index (BMI) change or weight change in adults.

METHODS

PubMed, Embase, Cochrane Library, Elsevier Science Direct, Science Online, MEDLINE and CINAHL were searched for English articles published before May 2017. A total of 16 cohort studies (n = 329 888 participants) from 8 countries were included in the analysis. Pooled relative risks (RR) or regression coefficients (β) with 95% confidence intervals (CI) were estimated. Heterogeneity and publication bias were tested, and sensitivity analysis was also performed.

RESULTS

We found that long sleep duration was associated with higher risk of obesity (RR [95% CI] = 1.04 [1.00-1.09], P = 0.037), but had no significant associations with weight gain, BMI change or weight change. Long sleep duration increased the risk of weight gain in three situations: among men, in studies with <5 years follow-up, and when sleep duration was 9 or more hours.

CONCLUSIONS

Long sleep duration was associated with risk of obesity in adults. More cohort studies with objective measures are needed to confirm this relationship.

Sleep Duration and Risk of Atrial Fibrillation: a Systematic Review

Background

Little is known about a possible association between sleep duration and the incidence of atrial fibrillation (AF), in healthy people. In this systematic review, we conducted a literature search to examine possible association between sleep duration and the incidence of AF.

Methods

Scientific databases (PubMed, Web of Knowledge and Embase) were searched using relevant Medical Subject Headings and keywords, to retrieve studies written in English and published until November 2017. Only observational studies were included. Since sleep duration categories were not consistent, it was feasible to run a meta-analysis.

Results

Six eligible studies were included. Long sleep duration (≥ 8 hours) was found to be associated with an increased risk of AF (adjusted hazard ratio (aHR) = 1.13; 95% CI: 1.00-1.27 and aHR= 1.5, 95% CI: 1.07-2.10) in two studies. One study reported that sleep duration less than 6 hours was associated with an increased risk of AF (aHR= 1.58, 95% CI: 1.18 -2.13) compared to sleeping for 6-7 hours. In two studies, mean sleep duration was lower in AF groups compared to the non-AF group. Insomnia was associated with an increased risk of AF in another study (aHR= 1.33, 95% CI: 1.25-1.41).

Conclusions

Unhealthy sleep duration, defined as either less than 6 hours or more than 8 hours, may be associated with an increased risk of AF.

Association between sleeping time and temporomandibular disorders in a sample of the South Korean population

Objective: This study investigated the relationship between sleeping time and temporomandibular disorders (TMDs).Methods: This study used data from the Fifth Korea National Health and Nutrition Examination Survey from 2010 to 2011. The final sample size consisted of 11,782 adults aged ≥19 years. Logistic regression analysis was performed to assess the relationship between sleeping time and TMD.Results: The adjusted odds ratios of the TMD group were 1.421 (1.067, 1.892) (Model 1), 1.388 (1.028, 1.873) (Model 2), and 1.360 (1.012, 1.826) (Model 3) for subjects with sleeping time ≤5 hours (p < 0.05) and 1.317 (0.992, 1.748) (Model 1), 1.358 (1.01, 1.827) (Model 2), and 1.352 (0.977, 1.872) (Model 3) for subjects with sleeping time ≥9 hours (p < 0.05).Conclusion: Sleeping time ≤5 hours and ≥9 hours were associated with an increased rate of TMD.

Assessing potential shared genetic aetiology between body mass index and sleep duration in 142,209 individuals

Observational studies find an association between increased body mass index (BMI) and short self-reported sleep duration in adults. However, the underlying biological mechanisms that underpin these associations are unclear. Recent findings from the UK Biobank suggest a weak genetic correlation between BMI and self-reported sleep duration. However, the potential shared genetic aetiology between these traits has not been examined using a comprehensive approach. To investigate this, we created a polygenic risk score (PRS) of BMI and examined its association with self-reported sleep duration in a combination of individual participant data and summary-level data, with a total sample size of 142,209 individuals. Although we observed a nonsignificant genetic correlation between BMI and sleep duration, using LD score regression (rg  = -0.067 [SE = 0.039], P = 0.092) we found that a PRS of BMI is associated with a decrease in sleep duration (unstandardized coefficient = -1.75 min [SE = 0.67], P = 6.13 × 10-7 ), but explained only 0.02% of the variance in sleep duration. Our findings suggest that BMI and self-reported sleep duration possess a small amount of shared genetic aetiology and other mechanisms must underpin these associations.

Objectively measured sleep and body mass index: a prospective bidirectional study in middle-aged and older adults

BACKGROUND

In recent years, short sleep has been increasingly recognized as a risk factor for obesity. However, current evidence has so far been limited to cross-sectional studies or longitudinal studies using self-reported sleep. Therefore, we explored the directionality of the association between objectively measured sleep and body mass index (BMI).

METHODS

The study consists of 1031 participants from the general population (52% women, 45-91 years at baseline). Sleep, BMI and waist circumference (WC) were measured twice across a follow-up of six years. BMI and WC were measured at the research center. Total sleep time (TST, hrs), sleep onset latency (SOL, min), sleep efficiency (SE, %) and wake after sleep onset (WASO, min) were estimated by a wrist-worn actigraph. In addition, cross-sectional and longitudinal associations in both directions were explored.

RESULTS

An hour shorter TST was cross-sectionally associated with approximately 0.5 kg/m² higher BMI. Longitudinally, longer TST and higher SE were associated with lower BMI (β_TST = -0.75, 95% CI: -1.08, -0.42; β_SE = -0.04, 95% CI: -0.08, -0.01). Conversely, one kg/m² higher BMI was prospectively associated with 0.02 h shorter TST (95% CI: -0.03, -0.01), and this association was more pronounced over time. Results from analyses with WC were in line with those of BMI.

CONCLUSIONS

This is the first study to explore bidirectionality in the association between objectively measured sleep and BMI in a large population of middle-aged and older adults. Indices of poor sleep were associated with higher and less stable BMI across time. Conversely, a high BMI was associated with a decrease in sleep duration. This confirms that the relation between sleep and body size is bidirectional, and changes in either sleep or BMI are likely to co-occur with changes in health through multiple pathways.

The Associations between Dietary Patterns and Short Sleep Duration in Polish Adults (LifeStyle Study)

Short sleep duration appears to put adults at risk of excessive energy intake and obesity; less is known specifically about how sleep quantity relates to dietary patterns. Therefore, the aim of this study was to assess the associations of dietary patterns (DPs) with short sleep duration. The data were collected in November 2016 through a cross-sectional quantitative survey among 972 Polish adults with both normal weight and excessive weight. Principal components analysis (PCA) was conducted to derive DPs. Logistic regression analysis was used to verify associations between short sleep duration (independent variable) and DPs (dependent variables). Five DPs ('Fast foods & sweets'-FF&S; 'Meat & meat products'-M&MP; 'Fruit & vegetable'-F&V; 'Wholemeal food'-WF; and 'Fruit & vegetable juices'-F&VJ) were identified. Adults whose diet was based both on fruit and vegetables (OR 0.62, 95% CI: 0.44⁻0.88; p < 0.01) and on fast food and sweets (OR 0.63, 95% CI: 0.44⁻0.99; p < 0.01) were less likely to be short sleepers on weekdays. On weekdays short sleep duration was associated with smaller odds of FF&S both for men (OR 0.58, 95% CI: 0.33⁻0.97; p < 0.05) and for women (OR 0.61, 95% CI: 0.38⁻0.98; p < 0.05), and with smaller odds of F&V (OR 0.34, 95% CI: 0.20⁻0.58; p < 0.001) for men. Short sleep duration on weekend days was associated with a smaller odds of F&VJ (OR 0.56, 95% CI: 0.30⁻0.96; p < 0.05- only in crude model) and higher odds of F&V (OR 1.70, 95% CI: 1.02⁻3.11; p < 0.05) for women, and with a smaller odds of FF&S (OR 0.37, 95% CI: 0.17⁻0.79; p < 0.05) for men. The number of significant associations between dietary patterns and sleep duration was higher among people with normal weight and overweight compared to those with BMI ≥ 30. We found that both short sleep duration on weekdays and weekend days was associated with some dietary patterns including both healthy and unhealthy DPs. Gender significantly differed these relationships in groups with normal and excessive weight. Findings of the study confirmed the potential effectiveness of combined use of sleep duration and dietary patterns in the development of recommendations for prevention of obesity. Future studies are called for to evaluate these links using dietary patterns identified according to food intake.

Sleep duration and 24-hour ambulatory blood pressure in adults not on antihypertensive medications

Short sleep duration has been widely linked to increased cardiovascular morbidity and mortality. We performed a post hoc analysis of 24-hour ambulatory blood pressure monitoring (ABPM) in the Lifestyle Modification in Blood Pressure Lowering Study (LIMBS) and Penn Icelandic Sleep Apnea (PISA) Study. The 24-hour mean systolic blood pressure (BP) was 12.7 mm Hg higher in LIMBS (P < 0.001; n = 66) and 4.7 mm Hg higher in PISA (P = 0.005; n = 153) among participants with shorter sleep duration (less than 7 hours) compared to those with longer sleep duration (at least 7 hours). In multivariable adjusted models, shorter sleep duration was strongly associated with higher systolic BP on 24-hour ABPM, independent of nocturnal BP and in-office BP. There was no effect modification by obstructive sleep apnea. Adults with shorter sleep duration may benefit from screening with 24-hour ABPM to promote earlier detection of hypertension and potentially mitigate their increased risk for future cardiovascular disease.

Sleep Duration and Excessive Daytime Sleepiness Are Associated with Obesity Independent of Diet and Physical Activity

In the European Union, Czech Republic ranks 3rd and 6th for the incidence of obesity and cardiovascular diseases, respectively. Worldwide, short sleep duration and excessive daytime sleepiness (EDS) characterize obese subjects, which in turn exhibit scarce physical activity and unhealthy diet. We aimed to understand the relationship between irregular sleep patterns, obesity and lifestyle factors, such as diet and physical activity, in a vulnerable Czech population. 1482 members of the Kardiovize cohort, a random sample of the Czech urban population, were included in a cross-sectional study. Exposure variables included self-reported sleep duration and EDS, assessed by the Epworth Sleepiness Scale. Primary outcomes were BMI and waist-to-hip ratio or prevalence of obesity and central obesity. Covariates included physical activity and diet. Associations and interactions between variables were evaluated using logistic regression analyses. After adjustment for covariates, short sleep duration (<7 h) was associated with greater odds of overweight (BMI > 25; OR = 1.42; 95%CI = 1.06⁻1.90; p = 0.020) and obesity (BMI > 30; OR = 1.40; 95%CI = 1.02⁻1.94; p = 0.047), while EDS was associated with greater odds of central obesity (OR = 1.72; 95%CI = 1.06⁻2.79; p = 0.030), independent of diet and physical activity. However, due to the cross-sectional nature of our study, further prospective, large-scale studies are needed to evaluate the etiological link and causality between sleep disturbances and obesity.

Sleep Duration and Excessive Daytime Sleepiness Are Associated with Obesity Independent of Diet and Physical Activity

In the European Union, Czech Republic ranks 3rd and 6th for the incidence of obesity and cardiovascular diseases, respectively. Worldwide, short sleep duration and excessive daytime sleepiness (EDS) characterize obese subjects, which in turn exhibit scarce physical activity and unhealthy diet. We aimed to understand the relationship between irregular sleep patterns, obesity and lifestyle factors, such as diet and physical activity, in a vulnerable Czech population. 1482 members of the Kardiovize cohort, a random sample of the Czech urban population, were included in a cross-sectional study. Exposure variables included self-reported sleep duration and EDS, assessed by the Epworth Sleepiness Scale. Primary outcomes were BMI and waist-to-hip ratio or prevalence of obesity and central obesity. Covariates included physical activity and diet. Associations and interactions between variables were evaluated using logistic regression analyses. After adjustment for covariates, short sleep duration (<7 h) was associated with greater odds of overweight (BMI > 25; OR = 1.42; 95%CI = 1.06⁻1.90; p = 0.020) and obesity (BMI > 30; OR = 1.40; 95%CI = 1.02⁻1.94; p = 0.047), while EDS was associated with greater odds of central obesity (OR = 1.72; 95%CI = 1.06⁻2.79; p = 0.030), independent of diet and physical activity. However, due to the cross-sectional nature of our study, further prospective, large-scale studies are needed to evaluate the etiological link and causality between sleep disturbances and obesity.

Sleep and Obesity

Rising global prevalence and incidence of obesity lead to increased cardiovascular-renal complications and cancers. Epidemiological studies reported a worldwide trend towards suboptimal sleep duration and poor sleep quality in parallel with this obesity epidemic. From rodents and human models, it is highly plausible that abnormalities in sleep, both quantity and quality, impact negatively on energy metabolism. While excess dietary intake and physical inactivity are the known drivers of the obesity epidemic, promotion of healthy sleep habits has emerged as a new target to combat obesity. In this light, present review focuses on the existing literature examining the relationship between sleep physiology and energy homeostasis. Notably, sleep dysregulation perturbs the metabolic milieu via alterations in hormones such as leptin and ghrelin, eating behavior, neuroendocrine and autonomic nervous systems. In addition, shift work and trans-meridian air travel may exert a negative influence on the hypothalamic-pituitary-adrenal axis and trigger circadian misalignment, leading to impaired glucose tolerance and increased fat accumulation. Amassing evidence has also suggested that uncoupling of the circadian clock can increase the risk of adverse metabolic health. Given the importance of sleep in maintaining energy homeostasis and that it is potentially modifiable, promoting good sleep hygiene may create new avenues for obesity prevention and treatment.

Sleep health disparity: the putative role of race, ethnicity and socioeconomic status

Sleep plays a pivotal role in both physical and mental health. Sleep quality can be affected by many socio demographic factors, such as race and/or ethnicity, as well as socio economic status (SES). Chronic sleep deprivation is associated with unhealthy behaviors such as alcohol abuse and also places individuals at risk for chronic diseases including obesity, cardiovasculardisease (CVD), depression, and/or anxiety. This review explores the common socio demographic factors and SES that can lead to sleep disturbances. Among these factors are shift work, poor dietary habits, smoking and alcohol abuse. Such factors need to be considered by health care providers in the clinical assessment and management plans of patients with sleep disorders.

Analysis of the Relationship between Sleep Duration and Body Mass Index in a South Korean Adult Population: A Propensity Score Matching Approach

Background

One-third of the present adults in South Korea are obese, and previous studies have demonstrated that sleep duration is considered a risk factor for obesity. Hence, I assessed the relationship between sleep duration and body mass index in a South Korean adult population.

Methods

This cross-sectional study consists of a representative sample of 4,218 South Korean adults (20–64 years) who participated in the sixth Korea National Health and Nutrition Examination Survey (2015). As statistical analysis methods, data were analyzed using chi-square test and multiple logistic regression. Propensity score matching (PSM) was applied to control selection bias, and obesity-related factors were used as covariates in PSM.

Results

According to the multiple logistic regression analysis, people who sleep for more than seven hours a day were less likely to be obese than those who sleep for less than seven hours a day in the pre-match (OR = 0.75, 95%CI = 0.65–0.88) and post-match (OR = 0.77, 95%CI = 0.65–0.90) samples.

Conclusions

This finding suggests that South Korean adults who reported sleeping more than 7 hours a day were linked to decreased body mass index. Hence, the proper amount of sleep is necessary to reduce the prevalence of obesity in this population.

Longitudinal assessment of daily activity patterns on weight change after involuntary job loss: the ADAPT study protocol

Background

The World Health Organization has identified obesity as one of the most visible and neglected public health problems worldwide. Meta-analytic studies suggest that insufficient sleep increases the risk of developing obesity and related serious medical conditions. Unfortunately, the nationwide average sleep duration has steadily declined over the last two decades with 25% of U.S. adults reporting insufficient sleep. Stress is also an important indirect factor in obesity, and chronic stress and laboratory-induced stress negatively impact sleep. Despite what we know from basic sciences about (a) stress and sleep and (b) sleep and obesity, we know very little about how these factors actually manifest in a natural environment. The Assessing Daily Activity Patterns Through Occupational Transitions (ADAPT) study tests whether sleep disruption plays a key role in the development of obesity for individuals exposed to involuntary job loss, a life event that is often stressful and disrupting to an individual’s daily routine.

Methods

This is an 18-month closed, cohort research design examining social rhythms, sleep, dietary intake, energy expenditure, waist circumference, and weight gain over 18 months in individuals who have sustained involuntary job loss. Approximately 332 participants who lost their job within the last 3 months are recruited from flyers within the Arizona Department of Economic Security (AZDES) Unemployment Insurance Administration application packets and other related postings. Multivariate growth curve modeling will be used to investigate the temporal precedence of changes in social rhythms, sleep, and weight gain.

Discussion

It is hypothesized that: (1) unemployed individuals with less consistent social rhythms and worse sleep will have steeper weight gain trajectories over 18 months than unemployed individuals with stable social rhythms and better sleep; (2) disrupted sleep will mediate the relationship between social rhythm disruption and weight gain; and (3) reemployment will be associated with a reversal in the negative trajectories outlined above. Positive findings will provide support for the development of obesity prevention campaigns targeting sleep and social rhythms in an accessible subgroup of vulnerable individuals.

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.

The Association Between Extreme Sleep Duration and Cardiac Autonomic Control in Community-Dwelling Older Adults: The Yilan Study, Taiwan

Backgrounds

The aims of the present study were to determine the associations and sex-specific relationships between extreme sleep duration and cardiac autonomic control in a cohort of older individuals.

Methods

A community-based survey was conducted in Yilan City, Taiwan. Community-dwelling older adults aged ≥65 were randomly selected to participate. Extreme sleep durations were defined as either short sleep (≤5 hours) or long sleep (≥8 hours). Cardiac autonomic control was evaluated using the parameters of frequency-domain analysis of heart rate variability.

Results

Of 1,721 participants, 58.7% were female. In multiple logistic regression analyses, short sleep duration did not correlate with any of the unhealthier parameters of heart rate variability. In contrast, long sleep duration was associated with elevated risk for poor high-frequency values (odds ratio [OR]: 1.83, 95% confidence interval [CI]: 1.34-2.50) and the unfavorable low-frequency values (OR: 1.44, 95% CI: 1.05-1.97). When stratified by sex, the associations between extreme sleep duration and poor heart rate variability were more robust in males.

Conclusions

Poor cardiac autonomic control may underlie the link between extreme sleep duration and adverse health outcomes in older adults. A sex-specific relationship between poor cardiac autonomic function and extreme sleep duration also was found.

Investigating the Bidirectional Associations of Adiposity with Sleep Duration in Older Adults: The English Longitudinal Study of Ageing (ELSA)

Cross-sectional analyses of adiposity and sleep duration in younger adults suggest that increased adiposity is associated with shorter sleep. Prospective studies have yielded mixed findings, and the direction of this association in older adults is unclear. We examined the cross-sectional and potential bi-directional, prospective associations between adiposity and sleep duration (covariates included demographics, health behaviours, and health problems) in 5,015 respondents from the English Longitudinal Study of Ageing (ELSA), at baseline and follow-up. Following adjustment for covariates, we observed no significant cross-sectional relationship between body mass index (BMI) and sleep duration [(unstandardized) B = −0.28 minutes, (95% Confidence Intervals (CI) = −0.012; 0.002), p = 0.190], or waist circumference (WC) and sleep duration [(unstandardized) B = −0.10 minutes, (95% CI = −0.004; 0.001), p = 0.270]. Prospectively, both baseline BMI [B = −0.42 minutes, (95% CI = −0.013; −0.002), p = 0.013] and WC [B = −0.18 minutes, (95% CI = −0.005; −0.000), p = 0.016] were associated with decreased sleep duration at follow-up, independently of covariates. There was, however, no association between baseline sleep duration and change in BMI or WC (p > 0.05). In older adults, our findings suggested that greater adiposity is associated with decreases in sleep duration over time; however the effect was very small.

Self-reported short sleep duration and insomnia symptoms as predictors of post-pregnancy weight change: Results from a cohort study

This study aims to investigate whether change in sleep duration and insomnia symptoms in the postpartum period is related to change in body mass index from before to 2 years after pregnancy. This study is based on self-report data from a Norwegian cohort, the AHUS Birth Cohort Study. Data were collected at 8 weeks (T1) and 2 years (T2) postpartum. Data from 812 women were analyzed. The results showed that only women with symptoms of insomnia at both T1 and T2 (persistent symptoms) had a greater increase in body mass index compared to women with no insomnia symptoms at T1 or T2.The results indicate that persistent insomnia symptoms are related to a greater increase in body mass index.

Relationships of Sleep Duration With Weight-Related Behaviors of U.S. College Students

This study describes sleep behaviors of U.S. college students (N = 1,252; 18-24 years old; 59% female) and examines associations of sleep duration with weight-related behaviors. More than one quarter of participants slept < 7 hr/night and had mean Pittsburgh Sleep Quality Index (PSQI) scores indicating poor sleep quality. There were significant differences for all PSQI scales among sleep duration categories, < 7 hr (n = 344), 7-8 hr (n = 449), ≥ 8 hr (n = 459) sleep/night. Compared to those who slept ≥ 8 hr, those who slept < 8 hr had significantly more negative eating attitudes (2% higher), poorer internal regulation of food (4% lower), and greater binge eating (4% higher) scores. Findings advocate for health care professionals to evaluate sleep behaviors of college students during office visits and promote good sleep behaviors.

Sleep Duration and Obesity in Adults: What Are the Connections?

Collectively, cross-sectional and longitudinal studies on self-reported sleep duration and obesity do not show a clear pattern of association with some showing a negative linear relationship, some showing a U-shaped relationship, and some showing no relationship. Associations between sleep duration and obesity seem stronger in younger adults. Cross-sectional studies using objectively measured sleep duration (actigraphy or polysomnography (PSG)) also show this mixed pattern whereas all longitudinal studies to date using actigraphy or PSG have failed to show a relationship with obesity/weight gain. It is still too early and a too easy solution to suggest that changing the sleep duration will cure the obesity epidemic. Given novel results on emotional stress and poor sleep as mediating factors in the relationship between sleep duration and obesity, detection and management of these should become the target of future clinical efforts as well as future research.