A prospective study of total sleep duration and incident metabolic syndrome: the ARIRANG study

Screen Time and Hours of Sleep Influence the Estimate Risk of Diabetes Mellitus and Metabolic Syndrome in Healthy Young Males

Objective: Screen time (ST) has shown negative effects on physical and mental health, with an increase in the prevalence of overweight, metabolic syndrome (MetS), and obesity. The time spent in front of the screens was also associated with higher odds of selecting indicators of cardiometabolic disease in adulthood. In view of this, the aim of this study was to identify the risk of MetS and type 2 diabetes mellitus (T2DM) in healthy young males and relate it to ST and sleep time. Methods: We evaluated physical and laboratory characteristics, dichotomous diagnosis criteria, and continuous scores to assess MetS and Finnish Diabetes Risk Score questionnaire to measure the T2DM risk. Results: The means of MetS dichotomous and continuous severity criteria, among individuals with <7 hr of sleep, were higher than those with adequate sleep. We did not observe a direct impact of ST on the risk of MetS; nevertheless, >8 hr of ST increased 1.22 points in the T2DM risk. Conclusion: Excessive ST increased the risk of T2DM, but not of MetS. Moreover, sleeping <7 hr was associated with a higher mean of dichotomous and continuous severity criteria for MetS.

Short sleep duration is associated with higher risk of central obesity in adults: A systematic review and meta-analysis of prospective cohort studies

Background and Objective

The relationship between sleep duration and obesity has been the focus of numerous investigations. This systematic review and meta-analysis of prospective cohort studies aimed to assess the relationship between sleep duration, abdominal obesity, and body composition.

Methods

PubMed, Scopus, and Web of Science were searched until February 2024. Cohort studies that assessed the relationship between sleep duration at night and central obesity measures or body composition indices in adults were included. The quality of studies was assessed using the Newcastle-Ottawa scale. Random-effects meta-analysis was conducted on studies that reported risk ratio (RR) and 95% confidence intervals (CIs).

Results

Eighteen studies were eligible to be included. Eleven out of the 18 studies were not included in the analysis as 10 studies did not report RR, and in one study, the definition of short and normal sleep duration was different from others. The results of the meta-analysis indicated that short sleep duration was significantly associated with abdominal obesity (RR = 1.08; 95% CI: 1.04-1.12; I 2 = 49.1%, n = 7), but long sleep duration was not (RR = 1.02; 95% CI: 0.83-1.24; I 2 = 98.2%, n = 6).

Conclusions

Short sleep duration was associated with a slightly higher risk of central obesity, while long sleep duration was not.

Association between Sleep Duration and Metabolic Disorders among Filipino Immigrant Women: The Filipino Women's Diet and Health Study (FiLWHEL)

Background

Sleep plays a complex role in metabolic regulation, and the underlying linkage has not been clearly defined. We investigated the association between sleep duration and metabolic disorders in Filipino immigrants in Korea.

Methods

We analyzed 410 participants from the 2014 to 2016 baseline population of the Filipino Women's Diet and Health Study. Usual sleep duration was self-reported, and anthropometric parameters were measured directly. Blood glucose, lipid, and insulin levels were examined from fasting serum samples. We used general linear models to acquire least squares (LS) means and logistic regression models to calculate odds ratios to test the cross-sectional association between sleep duration and metabolic markers with 95% confidence intervals (CIs).

Results

We found a statistically significant linear association between increased sleep duration and elevated triglycerides, total cholesterol, and low-density lipoprotein cholesterol (LDL-C). LS means (95% CI) of <5, 5-6, 7-8, and >8 hours of sleep were 81.74 (71.43 to 93.54), 85.15 (76.65 to 94.59), 86.33 (77.84 to 95.75), and 105.22 (88.07 to 125.71), respectively, for triglycerides (P trend=0.049) and 174.52 (165.02 to 184.57), 180.50 (172.79 to 188.55), 182.51 (174.83 to 190.53), and 190.16 (176.61 to 204.74), respectively, for total cholesterol (P trend= 0.042). For LDL-C, the LS means (95% CI) were 97.34 (88.80 to 106.71), 100.69 (93.73 to 108.18), 104.47 (97.35 to 112.10), and 109.43 (96.94 to 123.54), respectively (P trend=0.047). Statistical significance persisted after additional adjustment for body mass index. The association with triglycerides was limited to current alcohol drinkers (P interaction=0.048).

Conclusion

Longer sleep duration was associated with increased triglyceride, total cholesterol, and LDL-C levels. The association with triglycerides was more pronounced among moderate alcohol drinkers.

Short sleep duration and atrial fibrillation risk: A comprehensive analysis of observational cohort studies and genetic study

BACKGROUND

Previous observational studies are inconclusive on whether an association exists between short sleep duration and the high risk of developing atrial fibrillation (AF). Understanding their potential association would be of great clinical significance. Thus, in this study, we aimed to explore their causal relationship.

METHODS AND RESULTS

We meta-analyzed the association between short sleep duration and the risk of developing AF by including six observational studies. Based on genetic susceptibility analysis using the mendelian randomization (MR) method, we identified 16 genetic loci that might link short sleep duration and the high risk of developing AF. Meta-analysis showed a significant association between short sleep duration and a higher risk of developing AF (RR = 1.06, 95% CI 1.02-1.11, P = 0.005). However, the fixed-effect and random-effect inverse variance weighted (IVW) models using the MR method showed a non-obvious effect of short sleep duration on the risk of developing AF (OR, 0.979; 95% CI, 0.880-1.089, P = 0.693; OR, 0.979; 95% CI, 0.857-1.117, P = 0.750, respectively). Other models, also showed no statistical difference. No heterogeneity or asymmetry was observed, as Cochran's Q test showed. The leave-one-out sensitivity analysis demonstrated good robust results, which were not subject to directional pleiotropy.

CONCLUSION

Meta-analysis and MR analysis demonstrated inconsistent results on the relationship between short sleep duration and a high risk of developing AF. Specifically, while meta-analysis confirmed that short sleep duration increases the risk of developing AF, MR analysis did not support a causal association between genetically determined short sleep and risk of AF.

The Relationship between Sleep Duration and Metabolic Syndrome Severity Scores in Emerging Adults

BACKGROUND

Research suggests sleep duration can influence metabolic systems including glucose homeostasis, blood pressure, hormone regulation, nervous system activity, and total energy expenditure (TEE), all of which are related to cardiometabolic disease risk, even in young adults. The purpose of this study was to examine the relationship between sleep duration and metabolic syndrome severity scores (MSSS) in a sample of emerging adults (18-24 y/o).

METHODS

Data were collected between 2012 and 2021 from the College Health and Nutrition Assessment Survey, an ongoing, cross-sectional study conducted at a midsized northeastern university. Anthropometric, biochemical, and clinical measures were obtained following an overnight fast and used to assess the prevalence of metabolic syndrome (MetS). MetS severity scores (MSSS) were calculated using race- and sex-specific formulas. Sleep duration was calculated from the difference in self-reported bedtime and wake time acquired through an online survey. ANCOVA was used to examine the relationship between sleep duration and MetS severity score while adjusting for covariates (age, sex, BMI, physical activity level, smoking status, alcohol consumption, and academic major).

RESULTS

In the final sample (n = 3816), MetS (≥3 criteria) was present in 3.3% of students, while 15.4% of students presented with ≥2 MetS criteria. Mean MSSS was -0.65 ± 0.56, and the reported sleep duration was 8.2 ± 1.3 h/day. MSSS was higher among low sleepers (<7 h/day) and long sleepers (>9 h/day) compared to the reference sleepers (7-8 h/day) (-0.61 ± 0.02 and -0.63 ± 0.01 vs. -0.7 ± 0.02, respectively, p < 0.01).

CONCLUSIONS

Our findings suggest short (<7 h/day) and long (>9 h/day) sleep durations raise the risk of MetS in a sample of emerging adults. Further research is needed to elucidate the impact of improving sleep habits on future disease risk.

Association between Sleep Duration and Symptoms of Depression Aged between 18 and 49: The Korea National Health and Nutrition Examination Survey (KNHANES Ⅶ) from 2016 to 2018

This study aimed to determine the association between symptoms of depression and sleep duration in a representative sample of the Korean population. Using national cross-sectional data from the seventh Korea National Health and Nutrition Examination Surveys (KNHANES-VII), 5461 adults aged 18−49 years were analyzed using logistic regression models. The proportions of participants with total daily sleep durations (24 h) of <6 h, 6−8 h, and ≥9 h were 26.2%, 60.6%, and 13.3%, respectively. The proportions of individuals with symptoms of depression in the <6 h, 6−8 h, and ≥9 h sleep duration groups were 37.4%, 46.3%, and 16.3%, respectively. The odds ratios (ORs) were significantly higher in the <6 h and ≥9 h sleep groups than in the 6−8 h sleep group. There was a significant association between short (<6 h/day) and long (≥9 h/day) sleep duration and symptoms of depression among the general Korean population. In particular, our findings suggest that short sleep (<6 h/day) is more associated with symptoms of depression than long sleep (≥9 h/day).

Diffusion of a Lifelog-Based Digital Healthcare Platform for Future Precision Medicine: Data Provision and Verification Study

We propose a method for data provision, validation, and service expansion for the spread of a lifelog-based digital healthcare platform. The platform is an operational cloud-based platform, implemented in 2020, that has launched a tool that can validate and de-identify personal information in a data acquisition system dedicated to a center. The data acquired by the platform can be processed into products of statistical analysis and artificial intelligence (AI)-based deep learning modules. Application programming interfaces (APIs) have been developed to open data and can be linked in a programmatic manner. As a standardized policy, a series of procedures were performed from data collection to external sharing. The proposed platform collected 321.42 GB of data for 146 types of data. The reliability and consistency of the data were evaluated by an information system audit institution, with a defects ratio of approximately 0.03%. We presented definitions and examples of APIs developed in 17 functional units for data opening. In addition, the suitability of the de-identification tool was confirmed by evaluating the reduced risk of re-identification using quasi-identifiers. We presented specific methods for data verification, personal information de-identification, and service provision to ensure the sustainability of future digital healthcare platforms for precision medicine. The platform can contribute to the diffusion of the platform by linking data with external organizations and research environments in safe zones based on data reliability.

The Relationship Between Sleep Duration and Blood Lipids Among Chinese Middle-Aged and Older Adults: Cross-Lagged Path Analysis From CHARLS

This study used data from the China Health and Retirement Longitudinal Study to investigate the temporal relationship between blood lipids and sleep duration in Chinese middle-aged and older adults. We used medical examinations and questionnaire data of 5,016 Chinese middle-aged and older adults (age 45+) in 2011 and 2015. Cross-lagged path analysis was performed to examine the bidirectional relationships between blood lipids and sleep duration. Sleep duration and lipids data were analyzed as continuous variables. Temporal relationships between sleep duration and HDL-cholesterol, LDL-cholesterol, total cholesterol, and triglycerides were different. Sleep duration was negatively associated with HDL-cholesterol 4 year later (β₁ = −0.171, P = 0.005), and HDL-cholesterol was negatively associated with sleep duration 4 year later (β₂ = −0.006, P = 0.002). Longer sleep duration was associated lower levels of LDL-cholesterol (β₁ = −0.275, P = 0.097) and total cholesterol (β₁ = −0.329, P = 0.096) 4 year later. There was a positive correlation between triglycerides and sleep duration. The path coefficient from triglycerides to sleep duration 4 year later (β₂ = 0.001, P = 0.018) was greater than that from sleep duration to triglycerides 4 year later (β₁ = 0.109, P = 0.847), with P = 0.030 for the difference between β₁ and β₂. In stratified analysis, we found that the strength and direction of the relationships may be related to age and BMI. Effects of sleep duration on blood lipids were only observed among participants aged <60 years, while the effect in the opposite direction was observed in older adults (age 60+), and the cross-lagged path coefficients were more significant in adults with BMI > 25.

Sex-specific association of sleep duration with subclinical indicators of metabolic diseases among asymptomatic adults

Background

Accumulating evidence suggests sleep duration may be involved in metabolic regulation. However, studies regarding the association with the early stage of the metabolic disease are limited, and the findings were inconsistent.

Methods

A study among 4922 asymptomatic adults was conducted based on a Chinese national survey in 2009. The early stage of metabolic diseases was evaluated using three proxies: triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C), the product of triglyceride and fasting glucose (TyG), and lipid accumulation product (LAP). Multivariable linear and logistic regression models were used to explore the associations of sleep duration with the three indicators.

Results

The linear regression models revealed that, among females, sleep duration <7 h per day, compared with 7-9 h, was associated with an increased value of LAP and TyG by 25.232% (95%CI: 10.738%, 41.623%) and 0.104 (95%CI: 0.024, 0.185), respectively, in the crude model. The effects were attenuated but remained significant for LAP (11.405%; 95%CI: 1.613%, 22.262%). Similarly, the logistic regression models further found that sleep duration <7 h per day could increase the risk of elevated LAP (OR: 1.725, 95CI%:1.042, 2.856) after adjusting for multiple covariates. By contrast, no associations were found among males.

Conclusions

Short sleep duration was associated with subclinical indicators of metabolic diseases, and females were more susceptible to the association.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-022-01626-w.

Effects of sleep habits on acute myocardial infarction risk and severity of coronary artery disease in Chinese population

Background

Growing evidence indicates that poor sleep harms health. Early to bed and early to rise is considered as a healthy lifestyle in Chinese population. The current study aimed to examine the effects of sleep habits on acute myocardial infarction (AMI) risk and severity of coronary artery disease (CAD) in Chinese population from two centers.

Methods

A total of 873 patients including 314 AMI cases and 559 controls were recruited from the inpatient cardiology department of the Affiliated Jiangning Hospital and the First Affiliated Hospital of Nanjing Medical University. 559 controls included 395 CAD cases and 164 non-CAD cases. We used a 17-item sleep factors questionnaire (SFQ) to evaluate sleep habits comprehensively by face-to-face interview. The severity of CAD was assessed by Gensini score in AMI and CAD groups. The effects of sleep factors on AMI risk and Gensini score were examined by unconditional logistic regression.

Results

After mutually adjustment for other sleep factors and demographic characteristics, the timing of sleep (24:00 and after) and morning waking (after 7:00) and sleep duration (< 6 h) were associated with increased risk of AMI (OR = 4.005, P < 0.001, OR = 2.544, P = 0.011 and OR = 2.968, P < 0.001, respectively). Lower level of light exposure at night was correlated with reduced risk of AMI (OR = 0.243, P = 0.009). In subgroup analysis by age, both late sleep timing and short sleep duration were associated with increased risk of AMI regardless of age. In subjects with age ≤ 65 years, daytime napping was related to reduced risk of AMI (OR = 0.645, P = 0.046). In subjects with age > 65 years, the frequency of night-time waking (3 times) was associated with increased risk of AMI (OR = 3.467, P = 0.035). Short sleep duration was correlated with increased risk of high Gensini score (OR = 2.374, P < 0.001).

Conclusion

Sleep insufficiency is an important risk factor both for AMI risk and CAD severity. Late sleeping is also associated with increased risk of AMI. In young and middle-aged people, regular naps may have a protective effect.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02251-8.

Sleep duration and risk of hyperlipidemia: a systematic review and meta-analysis of prospective studies

PURPOSE

Current studies indicate that the association between sleep duration and risk of hyperlipidemia is uncertain. This systematic review aimed to evaluate relevant prospective studies and make a definite conclusion.

METHODS

Three databases were searched for prospective studies on the relationship between sleep duration and hyperlipidemia risk from their inception to October 2020.

RESULTS

We identified twelve studies involving 114,439 participants. Follow-up for incident hyperlipidemia ranged from 200 days to 10 years. Neither long (RR:1.00, 95%CI:0.90-1.11, P > 0.05) nor short (RR:0.99, 95%CI:0.94-1.05, P > 0.05) sleep duration had a significant association with increased hyperlipidemia risk in adults. However, long sleep duration was decidedly associated with low HDL-C (RR:0.19, 95%CI: - 0.03-0.40, P < 0.05) and high triglycerides (RR: - 0.20, 95%CI: - 0.43-0.03, P < 0.05) in children and adolescents.

CONCLUSION

Long sleep duration has strong associations with risks of low HDL-C and high triglycerides in children and adolescents. The mechanisms underlying this association deserves to be explored in future studies.

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

We examined the association between self-reported sleep duration and metabolic syndrome (MetS). Data were collected from 36 cross-sectional and 9 longitudinal studies with a total of 164,799 MetS subjects and 430,895 controls. Odds ratios (ORs) for prevalent MetS and risk ratios (RRs) for incident MetS were calculated through meta-analyses of adjusted data from individual studies. Short sleep duration was significantly associated with increased prevalent MetS (OR = 1.11, 95% CI = 1.05-1.18) and incident MetS (RR = 1.28, 95% CI = 1.07-1.53) in cross-sectional and longitudinal studies, respectively. Furthermore, long sleep duration was significantly associated with increased prevalent MetS in cross-sectional studies (OR = 1.14, 95% CI = 1.05-1.23), but not incident MetS (RR = 1.16, 95% CI = 0.95-1.41) in longitudinal studies. Interestingly, the association between long sleep and prevalent MetS was found in sleep duration defined by 24-h sleep (including naps) rather than nighttime sleep. Our findings suggest 1) a "U-shape" relationship between sleep duration and MetS in cross-sectional studies and 2) association between short sleep duration, but not long sleep duration with incident MetS. Future studies should shed light on the underlying mechanisms related to the association between sleep duration and MetS and examine if normalizing sleep duration reduces MetS risk in the general population.

Sleep Duration and the Risk of Metabolic Syndrome in Adults: A Systematic Review and Meta-Analysis

Objective: Epidemiological studies have reported inconsistent findings for the association between sleep duration and metabolic syndrome. We aimed to clarify the effects of short and long sleep durations on metabolic syndrome in adults by performing a meta-analysis. Methods: Adopting random-effects models, this study analyzed the effects of short and long sleep durations based on data from prospective cohort studies and cross-sectional studies retrieved from four electronic databases from inception to May 2020. Results: We collected data from 235,895 participants included in nine prospective cohort studies and 340,492 participants included in 27 cross-sectional studies. In cohort studies, short sleep duration was associated with an increased risk of metabolic syndrome (RR, 1.15; 95% CI, 1.05-1.25, I 2 = 63.1%, P < 0.001) compared with normal sleep duration. While long sleep duration was not associated with new-onset metabolic syndrome (RR, 1.02, 0.85-1.18, I 2 = 38.0%, P = 0.491). In cross-sectional studies, both short (OR, 1.06, 95% CI, 1.01-1.11, I 2 = 66.5%, P < 0.001) and long (OR, 1.11, 95% CI, 1.04-1.17, I 2 = 73.8%, P < 0.001) sleep durations were associated with a high prevalence of metabolic syndrome. Conclusions: Only a short sleep duration was associated with an increased risk of metabolic syndrome. Future studies should address whether the association is casual and modifiable.

Longitudinal association between sleep and 5-year incident metabolic syndrome in older Chinese adults: a community-based cohort study

PURPOSE

Our aim was to investigate the association between sleep and the development of metabolic syndrome (MetS) in Chinese older adults and to accumulate evidence for the prevention of MetS through sleep management.

METHODS

This prospective study followed 3005 participants aged over 60 derived from the Weitang Geriatric Diseases Study who were without MetS at baseline. MetS was defined according to the Adult Treatment Panel III (ATP III) criteria. Logistic regression models were fit to assess the association between sleep and MetS incident and a linear regression model was used to examine the impact of sleep duration on every component of MetS. Data on sleep-related parameters were obtained based on a self-reported questionnaire.

RESULTS

After five-year follow-up, 13.51% participants developed MetS, of which 46.86% were women. The incidence of MetS was highest among adults who slept 6 h or less and lowest among those who slept 7 h after adjusted for multiple variables. Subgroup analyses showed no gender specificity. The variation of fasting plasma glucose (FBG) for ≥9 h per night was significantly lower than that for 7.01-7.99 h per night (β = -0.18, P < 0.05). Sleeping for 8-8.99 h also decreased the variation of diastolic blood pressure (DBP) compared to 7.01-7.99 h (β = -0.84, P < 0.05).

CONCLUSION

We conclude that both short and long sleep duration are risk factors for MetS incident in older adults.

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

PURPOSE

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

METHODS

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

FINDING

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

IMPLICATIONS

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

Association of self-reported sleep disturbances with ideal cardiovascular health in Brazilian adults: A cross-sectional population-based study

OBJECTIVE

To examine the association between sleep disturbances and cardiovascular health in Brazilian adults.

METHODS

We analyzed cross-sectional data from a nationally representative sample of 36,480 Brazilian adults ages 18 and over. Multivariate Poisson regression models were used to assess the association between sleep disturbances (difficulty falling asleep, frequent interruptions in sleep, or sleeping more than usual) and Life's Simple 7 (LS7) cardiovascular health (CVH) scores through consideration of four behaviors (smoking, physical activity, body mass index, and diet) and three biological factors (hypercholesterolemia, hypertension, and diabetes).

RESULTS

Adults with no sleep disturbances had better CVH, with higher mean LS7 CVH scores (4.2, 95% confidence interval [CI]: 4.1; 4.2) when compared to those experiencing some level of sleep disturbance within a 2-week timespan (3.8, 95% CI: 3.7; 3.8). Specifically, compared to those with no sleep disturbance, adults reporting sleep disturbances for half of the weekdays had significantly lower LS7 CVH mean scores (β = -0.02, 95% CI: -0.04; 0.01). Adults who had disturbances more than half of the weekdays had even lower scores (β = -0.06, 95% CI: -0.09; -0.02), followed by those who reported disturbances almost every day (β = -0.08, 95% CI: -0.11; -0.04), even after adjusting for age, sex, education status, depressive symptoms, and night shift work.

CONCLUSION

Brazilian adults with sleep disturbances are less likely to achieve ideal CVH. Given that sleep disturbances seem to be increasingly common in Brazil, recent gains in CVH mortality may be affected.

The association between daily naps and metabolic syndrome: Evidence from a population-based study in the Middle-East

BACKGROUND

Daily naps are a common habit in many Middle Eastern and Asian countries; however, little is known about the association between daily naps and other health consequences, including the presence of metabolic syndrome (MetS).

METHODS

Participants were recruited from the Mashhad stroke and heart atherosclerotic disorders study. We defined MetS according to International Diabetes Federation criteria. Nighttime sleeping hours were categorized into three categories: <6, 6-8, and >8 hours. Using logistic regression models, we analyzed the association between the duration of night-time sleep and daily naps with MetS and its different components.

RESULTS

A total of 9652 individuals were included in the study: 3859 with MetS (40%) and 5793 without MetS (60%), as the control group. Of all, 72% participants had a regular daily nap. Those with daily naps had a higher odd of MetS [Odds ratio:1.19, confidence interval: (1.08-1.33); P < .001]. We also observed significantly higher odds of obesity, central obesity, hypertriglyceridemia, and diabetes or impaired fasting glucose in these subjects. Men sleeping <6 hours per night had a lower odd of MetS. However, we observed higher odds of cardiovascular risk factors in participants sleeping <6 hours, including obesity and diabetes or IFG.

CONCLUSION

Napping is a common habit in middle Eastern countries. Although the cross-sectional design of our study cannot prove causality, we observed a significant association between the presence of MetS and daily naps. The public should be aware of this possibility and be educated about the importance of sleeping patterns.

The immune-sleep crosstalk in inflammatory bowel disease

Sleep disorders are progressively common and sometimes are associated with aberrant regulation of the adaptive and innate immune responses. Sleep interruption can increase the inflammatory burden by enhancing the pro-inflammatory cytokines particularly in patients with chronic diseases such as inflammatory bowel disease (IBD). IBD is a chronic inflammatory disease characterized by immune dysregulation, dysbiosis of gut microbiome, and poor-quality life. Therefore, this review highlights the crosstalk between sleep and immune responses during the progression of IBD.

Association between Sleep Quality and Duration and Periodontal Disease among University Students: A Cross-Sectional Study

The purpose of this cross-sectional study was to investigate the association between sleep quality and duration, and periodontal disease among a group of young Japanese university students. First-year students (n = 1934) at Okayama University who voluntarily underwent oral health examinations were included in the analysis. Sleep quality and duration were assessed by the Japanese version of the Pittsburgh Sleep Quality Index. Dentists examined Oral Hygiene Index-Simplified (OHI-S), probing pocket depth (PPD), and percentage of sites with bleeding on probing (BOP). Periodontal disease was defined as presence of PPD ≥ 4 mm and BOP ≥ 30%. Overall, 283 (14.6%) students had periodontal disease. Poor sleep quality was observed among 372 (19.2%) students. Mean (± standard deviation) sleep duration was 7.1 ± 1.1 (hours/night). In the logistic regression analysis, periodontal disease was significantly associated with OHI-S (odds ratio [OR]: 2.30, 95% confident interval [CI]: 1.83–2.90; p < 0.001), but not sleep quality (OR: 1.09, 95% CI: 0.79–1.53; p = 0.577) or sleep duration (OR: 0.98, CI: 0.87–1.10; p = 0.717). In conclusion, sleep quality and duration were not associated with periodontal disease among this group of young Japanese university students.

Shorter sleep duration is associated with lower GABA levels in the anterior cingulate cortex

BACKGROUND

Alterations in the levels of gamma-aminobutyric acid (GABA) and glutamate + glutamine (Glx), which are major inhibitory and excitatory neurotransmitters, respectively, are frequently associated with insomnia. Previous reports also suggested the involvement of the anterior cingulate cortex (ACC) and medial prefrontal cortex (mPFC) in insomnia and shorter sleep duration. In the current study, we investigated whether the GABA and Glx levels were altered in the ACC/mPFC in subclinical insomnia while focusing on the sleep duration.

METHODS

We examined levels of GABA and Glx in the ACC/mPFC of the brain with magnetic resonance spectroscopy in 166 individuals with subjective sleep complaints but without a diagnosis of insomnia. Participants were divided into two groups according to sleep duration (≥6 h/night: n = 79 vs. < 6 h/night: n = 74), which was measured using a wrist-worn actigraphy. Working memory function and overall subjective sleep quality were assessed with a computerized neuropsychological test and self-report questionnaire, respectively.

RESULTS

GABA levels in the ACC/mPFC were lower in the shorter sleep duration group relative to the longer sleep duration group (t = -2.21, p = 0.03). Glx levels did not differ between the two groups (t = -0.20, p = 0.84). Lower GABA levels were associated with lower spatial working memory performance in the shorter sleep duration group (β = -0.21, p = 0.03), but not the longer sleep duration group (β = 0.04, p = 0.72).

CONCLUSION

Shorter sleep duration was associated with lower GABA levels in the ACC/mPFC. These findings may provide insight into the underlying mechanisms of impaired working memory function related to insomnia and sleep loss.

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.

Evaluating the Effects of Different Sleep Supplement Modes in Attenuating Metabolic Consequences of Night Shift Work Using Rat Model

PURPOSE

To study the effects of chronic-simulated night shift work using the rat model and examines if a particular sleep supplement mode could be better in alleviating the effects.

METHODS

The male Wistar rats were randomly divided into the control (CTL: 8 rats) and night shift work (NW: 24 rats) groups of rats. Based on the sleep supplement strategy, the NW group was further segregated into three subgroups (8 rats each); late sleep supplement group (LSS), early sleep supplement group (ESS), and intermittent sleep supplement group (ISS). Sleep deprivation was achieved using the standard small-platform-over water method. Parameters such as animal body weight and food intake were measured daily. The intraperitoneal glucose tolerance test, fasting plasma insulin concentration, insulin resistance index and insulin sensitivity were measured twice, in the 4th and 8th weeks of the study. Plasma corticosterone concentration and pathological changes in islets (insulitis) were measured at the end of the 8th week.

RESULTS

In NW group, night work resulted in a gain of body weight and albeit lower than that of the CTL group. NW rats also had higher food intake, showed impaired glucose metabolism and higher plasma corticosterone concentration. The sleep supplement experiments suggested that compared to the other modes, intermittent sleep supplement had significantly low changes in the body weight, glucose metabolism and the islet cells.

CONCLUSION

Similar to previous studies, we also found that night shift work adversely impacts the body weight and glucose metabolism in rats. However, upon evaluating different sleep supplement strategies, we found the intermittent sleep supplement strategy to be most effective.

Sleep Apnea and Sleep Habits: Relationships with Metabolic Syndrome

Excess visceral adiposity is a primary cause of metabolic syndrome and often results from excess caloric intake and a lack of physical activity. Beyond these well-known etiologic factors, however, sleep habits and sleep apnea also seem to contribute to abdominal obesity and metabolic syndrome: Evidence suggests that sleep deprivation and behaviors linked to evening chronotype and social jetlag affect eating behaviors like meal preferences and eating times. When circadian rest and activity rhythms are disrupted, hormonal and metabolic regulations also become desynchronized, and this is known to contribute to the development of metabolic syndrome. The metabolic consequences of obstructive sleep apnea syndrome (OSAS) also contribute to incident metabolic syndrome. These observations, along with the first sleep intervention studies, have demonstrated that sleep is a relevant lifestyle factor that needs to be addressed along with diet and physical activity. Personalized lifestyle interventions should be tested in subjects with metabolic syndrome, based on their specific diet and physical activity habits, but also according to their circadian preference. The present review therefore focuses (i) on the role of sleep habits in the development of metabolic syndrome, (ii) on the reciprocal relationship between sleep apnea and metabolic syndrome, and (iii) on the results of sleep intervention studies.

Associations of sleep durations and sleep-related parameters with metabolic syndrome among older Chinese adults

PURPOSE

There is a lack of data on the role of sleep in the development of metabolic syndrome (MetS) in older adults. We aimed to examine the associations of sleep durations at night and other sleep-related parameters with the presence of MetS in older Chinese adults.

METHODS

Data of 4579 individuals aged 60 years or older from the Weitang Geriatric Disease Study were analyzed. MetS was diagnosed based on the Adult Treatment Panel III (ATP III) criteria. Information regarding sleep durations and other sleep-related parameters was collected by questionnaires.

RESULTS

Compared with those with daytime napping, individuals without daytime napping were at an increased risk of MetS (odds ratio [OR] = 1.23; 95% confidence interval [CI] = 1.03-1.47). Each hour increase in daytime napping increased the risk of MetS by 33% (OR = 1.33; 95% CI = 1.15-1.52). After adjusting for the effect of age and gender, a J-shaped association between sleep durations at night and the presence of MetS was observed. The risk of MetS was lowest among those who slept 7-8 h at night. Gender-stratified analysis indicated that the J-shaped relationship between sleep durations at night and MetS remained significant in men but not in women.

CONCLUSIONS

In older Chinese adults, sleep durations at night might have a dual effect on the risk of MetS and this effect was particularly pronounced in men. The results indicated that circadian rhythm might play an important role in the development of MetS in older populations.

Sleep problems are a strong predictor of stress-related metabolic changes in police officers. A prospective study

OBJECTIVE

Previous studies have shown that workers chronically exposed to occupational stress have an increased risk of metabolic syndrome (MetS) and sleep problems (SPs). The purpose of this study was to verify whether SPs mediate the relationship between stress and MetS.

METHOD

A 5-year prospective cohort study included 242 police officers from a rapid response unit engaged exclusively in maintaining law and order. Perceived stress levels were measured repeatedly with the demand-control-support and the effort-reward-imbalance questionnaires; insomnia symptoms were assessed with the Pittsburgh Sleep Quality Index; excessive daytime sleepiness was measured using the Epworth Sleepiness Scale. MetS and its components were evaluated at baseline and at follow-up.

RESULTS

During 5-year follow-up period, 26 new cases of MetS were identified. Both occupational stress and SPs were significantly related to incident cases of MetS. Insomnia symptoms showed a highly significant association with MetS (aOR 11.038; CI95% 2.867-42.493). Mediation analysis confirmed that SPs mediate the relationship between stress and MetS. A reciprocal relationship was found between job stress and SPs. Work-related stress was a significant predictor of insomnia symptoms, short sleep duration, sleep dissatisfaction, and sleepiness. Compared to the reference group, police officers with SPs at baseline had significantly higher odds of reporting high stress at follow-up.

CONCLUSION

SPs play a mediating role in the relationship between occupational stress and MetS. Prevention of MetS must include the control of stress factors and an increase in the resilience of workers, but correct sleep hygiene is also an essential factor.

The Association between Sleep Duration and Dizziness in Korean Women: The Korea National Health and Nutrition Examination Survey

BACKGROUND

The aim of this study was to investigate the association between sleep duration and dizziness in a representative Korean population.

METHODS

We analyzed data from the Korea National Health and Nutrition Examination Surveys (2010-2012). A total of 12,499 adults who completed otolaryngologic examinations were evaluated.

RESULTS

Both men and women with severely short sleep duration (≤ 5 hours) and severely long sleep duration (≥ 9 hours) tended to have higher dizziness prevalence. However, the adjusted odds ratio (OR) for sleep duration was only significant in women with dizziness after adjusting for confounders. Compared to that in an optimal sleep group (6-8 hr/day), the OR (95% confidence interval) for dizziness prevalence after adjusting for age and health behaviors (body mass index, smoking habit, alcohol consumption, level of exercise, metabolic syndrome, and tinnitus) was 1.473 (1.194-1.818) for the severely short sleep group (≤ 5 hr/day) and 1.472 (1.078-2.009) for the severely long sleep group (≥ 9 hr/day) only in women.

CONCLUSION

In the Korean population, dizziness was associated with shorter or longer sleep durations only among women. Further epidemiologic and experimental studies are necessary to clarify the impact of dizziness on sleep disorders.

Magnitude and Determinants of Patients at Risk of Developing Obstructive Sleep Apnea in a Non-Communicable Disease Clinic

Background and Objective: Obstructive sleep apnea (OSA) is a common chronic disorder worldwide, which can adversely affect the cardiovascular system among non-communicable disease (NCD) patients. It is underdiagnosed—or rather not diagnosed—in primary care settings due to the costly diagnostic techniques involved. This study aimed to assess the number of study participants at risk of developing OSA and to assess and quantify the risk factors associated with this disorder. Materials and Methods: A cross-sectional study was performed in an NCD clinic of a rural health training center, Karikalampakkam, Puducherry of South India from August 2018 to October 2018. A Modified Berlin Questionnaire (MBQ) was used to screen the study participants at risk for OSA. Four-hundred-and-seventy-three people aged 18 years and above were included in the study, using systematic random sampling. Respondents’ socio-demographic and morbidity characteristics, as well as clinical and anthropometric parameters including body weight, height, blood pressure, neck, hip and waist circumference were collected. Data was captured using Epicollect5 and analyzed using SPSS version 20.0. Results: One-fourth (25.8%) of the respondents were at high risk of developing OSA. In terms of gender, 27.9% of the men and 23.8% of the women were at high risk for OSA. In univariate analyses, the risk of developing OSA was significantly associated with a history of diabetes mellitus, hypertension, dyslipidemia and gastro-esophageal reflux disease, weight, body mass index, neck, waist and hip circumference, waist–hip ratio, and systolic and diastolic blood pressure. Multivariate logistic regression analysis showed that a history of dyslipidemia (aOR, 95% CI = 2.34, 1.22–4.48), body mass index (aOR, 95% CI = 1.15, 1.06–1.22) and waist circumference (aOR, 95% CI = 1.10, 1.07–1.14) emerged as significant predictors of risk for OSA. Conclusions: A considerable proportion of NCD patients with easily detectable attributes are at risk of developing OSA, but still remain undiagnosed at a primary health care setting. The results obtained using MBQ in this study were comparable to studies performed using polysomnography. Dyslipidemia, body mass index and waist circumference were independent risk factors for predicting a risk of developing OSA. Prospective studies are needed to confirm whether a reduction in these risk factors could reduce the risk for OSA.

Age Differences in the Relationship between Secondhand Smoke Exposure and Risk of Metabolic Syndrome: A Meta-Analysis

Secondhand smoke (SHS), a common environmental exposure factor, has become a serious public health problem. Metabolic syndrome is another worldwide clinical challenge. Our study tried to determine the age differences in the relationship between SHS and the risk of metabolic syndrome. Studies were searched in PubMed and Web of Science from 11 November to 30 November 2018. Eighteen studies were finally included based on inclusion and exclusion criteria. The relationship between SHS and the risk indicators of metabolic syndrome was analyzed. The weighted mean difference (WMD) of fasting plasma glucose (FPG), insulin, body mass index (BMI), and waist circumference (WC), and the standard mean difference (SMD) of total cholesterol, triglycerides, and low- and high-density lipoprotein-cholesterol (LDL-C, HDL-C) were calculated in a meta-analysis. SHS was positively associated with the level of insulin and WC. According to the subgroup analysis based on age difference, SHS was positively associated with FPG in the upper age group, and positively associated with LDL-C and negatively associated with HDL-C in the lower age group. BMI showed a more obvious positive correlation in the adults group than in the children and the teenagers group. In conclusion, the association of metabolic syndrome with SHS varies with age. When exposed to SHS, older people may be more susceptible to glucose metabolic disorder, but younger people may be more susceptible to lipid metabolic disorder.

Shift work and metabolic syndrome: A multi-center cross-sectional study on females of reproductive age

Shift work during reproductive age can be a risk factor for metabolic syndrome. The present study evaluated the association between shift work and metabolic syndrome during reproductive age. This multi-center cross-sectional correlational study was performed between September 2017 and May 2018. A total of 419 female shift and day workers were purposively recruited to the study from three central cities in Mazandaran, Iran. To diagnose metabolic syndrome based on the National Cholesterol Education Program Adult Treatment Panel III guidelines, the anthropometric measures, blood pressure, and levels of serum triglyceride, high-density lipoprotein and fasting blood sugar were taken. Data were analyzed using the independent-sample t, Chi-square and the Fisher's exact tests as well as the logistic regression analysis. Among the 419 participants, 28 were excluded during the study. The total prevalence of metabolic syndrome was 16.3%, and its prevalence among shift workers and day workers was 17.3 and 14.9%, respectively. The most prevalent components of metabolic syndrome were low serum level of high-density lipoprotein and abdominal obesity. Following adjustments for the effects of potential cofounders, the logistic regression analysis revealed that the odds of metabolic syndrome among shift workers was ~2 times greater than day workers (odds ratio, 1.83; 95% confidence interval, 0.088-3.79), although this association was statistically insignificant (P=0.10). The results of the current study suggest that shift work is associated with a greater risk of metabolic syndrome for women. The most important components of metabolic syndrome are low serum level of high-density lipoprotein and abdominal obesity, which are attributable to limited physical activity and high occupational stress. The risk of metabolic syndrome among female shift workers of reproductive age may be reduced through strategies, including awareness raising, dietary educations and provision of physical activity facilities in the workplace.

Gene and environmental interactions according to the components of lifestyle modifications in hypertension guidelines

Risk factors for hypertension consist of lifestyle and genetic factors. Family history and twin studies have yielded heritability estimates of BP in the range of 34–67%. The most recent paper of BP GWAS has explained about 20% of the population variation of BP. An overestimation of heritability may have occurred in twin studies due to violations of shared environment assumptions, poor phenotyping practices in control cohorts, failure to account for epistasis, gene-gene and gene-environment interactions, and other non-genetic sources of phenotype modulation that are suspected to lead to underestimations of heritability in GWAS. The recommendations of hypertension guidelines in major countries consist of the following elements: weight reduction, a healthy diet, dietary sodium reduction, increasing physical activity, quitting smoking, and moderate alcohol consumption. The hypertension guidelines are mostly the same for each country or region, beyond race and culture. In this review, we summarize gene-environmental interactions associated with hypertension by describing lifestyle modifications according to the hypertension guidelines. In the era of precision medicine, clinicians who are responsible for hypertension management should consider the gene-environment interactions along with the appropriate lifestyle components toward the prevention and treatment of hypertension. We briefly reviewed the interaction of genetic and environmental factors along the constituent elements of hypertension guidelines, but a sufficient amount of evidence has not yet accumulated, and the results of genetic factors often differed in each study.

Prospective associations among objectively and subjectively assessed sleep and the metabolic syndrome

OBJECTIVE

Subjective sleep disturbances have been associated with greater risk for concurrent and incident metabolic syndrome (MetS). Previous studies have not examined prospective associations among polysomnography-assessed sleep and the MetS, despite knowledge that self-reported sleep is subject to reporting bias, and that subjectively and objectively assessed sleep are weakly correlated.

METHOD

In the current study, objectively-assessed (polysomnography) and subjectively-assessed (Pittsburgh Sleep Quality Index, PSQI) sleep was measured in 145 adults at two timepoints, separated by 12-30 years. A continuous measure of the MetS was assessed at the second time point. Statistical analyses were adjusted for age, sex, lifetime history of major depressive disorder, follow-up time, and apnea-hypopnea index.

RESULTS

Polysomnography-assessed sleep duration, latency, efficiency, and slow wave sleep were not significantly prospectively associated with the MetS (ps ≥ 0.16). Self-reported longer sleep latency was prospectively associated with higher MetS scores in unadjusted (β = 0.29, p = 0.002) and adjusted models (β = 0.25, p = 0.009). Longer sleep latency was associated with higher fasting glucose levels (β = 0.47, p < 0.001).

CONCLUSION

Our study provides evidence that subjective and objective measures of sleep may differ in their ability to prospectively predict MetS.

Multiple poor sleep characteristics and metabolic abnormalities consistent with metabolic syndrome among white, black, and Hispanic/Latina women: modification by menopausal status

BACKGROUND

Poor sleep is a potential risk factor for metabolic syndrome (MetS), and its relationship with MetS may vary by race/ethnicity and menopausal status among women.

METHODS

We used Sister Study enrollment data from 2003 to 2009 to investigate the cross-sectional associations between multiple subjective sleep characteristics and having ≥ 3 prevalent metabolic abnormalities consistent with MetS among white, black, and Hispanic/Latina women. Self-reported sleep characteristics included average sleep duration (short [< 7 h] vs. recommended [7-9 h]), sleep debt (≥ 2-h difference between shortest and longest sleep duration, napping ≥ 3 times/week, and insomnia symptoms (difficulty falling or staying asleep). We used Poisson regression with robust variance to estimate adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs) to compare MetS prevalence between women with poor sleep (e.g., short sleep, sleep debt, frequent napping, or insomnia symptoms [all yes vs. no]) and non-poor sleep within menopausal status categories (premenopausal or postmenopausal). We adjusted for sociodemographic characteristics, mental health, and health behaviors.

RESULTS

Among 38,007 eligible women (13,988 premenopausal, 24,019 postmenopausal), mean age was 55 ± 8.8 years, racial/ethnic composition was 86.63% white, 8.53% black, and 4.84% Hispanic/Latina, and 12% had MetS. Associations between certain poor sleep characteristics [i.e., short sleep (PRpremenopausal = 1.23 [95% CI 1.06-1.42], PRpostmenopausal = 1.09 [1.02-1.16], pshort sleep*menopause = 0.0070) and insomnia symptoms (PRpremenopausal = 1.21 [1.05-1.41], PRpostmenopausal = 1.11 [1.05-1.18], pinsomnia symptoms*menopause = 0.035)] and prevalent MetS were stronger among premenopausal compared to postmenopausal women, but did not vary by race/ethnicity. Associations between concurrent short sleep/insomnia symptoms and MetS were stronger among white and Hispanic/Latina postmenopausal women compared to their black counterparts. Menopausal status and race/ethnicity did not modify positive associations for other poor sleep characteristics.

CONCLUSIONS

Poor sleep was positively associated with MetS prevalence. Associations between individual poor sleep characteristics (i.e., short sleep, insomnia symptoms) were stronger among premenopausal compared to postmenopausal women but did not vary by race/ethnicity.

Association of sleep disturbances with obesity, insulin resistance and the metabolic syndrome

Insufficient sleep, which has become endemic in recent years, has been variably associated with increased risk of obesity, disorders of glucose and insulin homeostasis, and the metabolic syndrome; to a lesser degree, so has excessive sleep. This review summarizes recent epidemiological and pathophysiological evidence linking sleep disturbances (primarily abnormalities of sleep duration) with obesity, insulin resistance, type 2 diabetes and the metabolic syndrome in children and adults.

Association between sleep duration and metabolic syndrome: a cross-sectional study

BACKGROUND

Both short and long sleep duration have been consistently studied as a risk factor for obesity, hyperglycemia and hypertension. In this cross-sectional study, we provide an updated analysis of the Health Examinees (HEXA) study on the association between sleep duration and metabolic syndrome (MetS) occurrence among Koreans age 40-69 year olds.

METHODS

A total of 133,608 subjects (44,930 men, 88,678 women) were enrolled in the HEXA study 2004-2013. Sleep duration was categorized into 4 sleep categories (< 6 h, 6 to < 8 h, 8 to < 10 h, ≥10 h). MetS criterion was based on the National Cholesterol Education Program, Adult Treatment Panel III. Logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Compared with individuals sleeping 6 to < 8 h per day, less than 6 h of sleep was associated with MetS (multivariable adjusted OR: 1.12, 95% CI: 1.05-1.19) and elevated waist circumference (1.15, 1.08-1.23) among men; with elevated waist circumference (1.09, 1.04-1.14) among women. Greater than 10 h of sleep was associated with MetS (1.28, 1.08-1.50) and elevated triglycerides (1.33, 1.14-1.56) among men; with MetS (1.40, 1.24-1.58), elevated waist circumference (1.14, 1.02-1.27), elevated triglycerides (1.41, 1.25-1.58), reduced high-density lipoprotein cholesterol (HDL-C) (1.24, 1.12-1.38), and elevated fasting glucose (1.39, 1.23-1.57) among women.

CONCLUSIONS

Less than 6 h of sleep is associated with elevated waist circumference among both men and women and with MetS among men only. Greater than 10 h of sleep is associated with MetS and elevated triglycerides among both men and women and with elevated waist circumference, reduced HDL-C, and elevated fasting glucose among women only.

Loss of Cardio-Protective Effects at the CDH13 Locus Due to Gene-Sleep Interaction: The BCAMS Study

Left ventricular mass index (LVMI) provides a metric for cardiovascular disease risk. We aimed to assess the association of adiponectin-related genetic variants resulting from GWAS in East Asians (loci in/near CDH13, ADIPOQ, WDR11FGF, CMIP and PEPD) with LVMI, and to examine whether sleep duration modified these genetic associations in youth. The 559 subjects aged 15–28 years were recruited from the Beijing Child and Adolescent Metabolic Syndrome study. Among the six loci, CDH13 rs4783244 was significantly correlated with adiponectin levels (p = 8.07 × 10⁻⁷). The adiponectin-rising allele in rs4783244 locus was significantly associated with decreased LVMI (p = 6.99 × 10⁻⁴) after adjusting for classical cardiovascular risk factors, and further for adiponectin levels, while no significant association was found between the other loci and LVMI. Moreover, we observed a significant interaction effect between rs4783244 and sleep duration (p = .005) for LVMI; the genetic association was more evident in long sleep duration while lost in short sleep duration. Similar interaction was found in the subgroup analysis using longitudinal data (p = .025 for interaction). In this young Chinese population, CDH13 rs4783244 represents a key locus for cardiac structure, and confers stronger cardio-protection in longer sleep duration when contrasted with short sleep duration.

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CDH13 rs4783244 represents a key locus for cardiac structure.

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The effect of CDH13 rs4783244 on reduced left ventricular mass index is significantly modified by sleep duration.

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Short sleep may contribute to the loss of CDH13 locus-mediated cardio-protective effects.

We analyzed the associations of five adiponectin-associated genetic variants with left-ventricular mass index (LVMI), a cardiovascular risk factor, in a population of 559 youth. We found a significant protective association of CDH13 rs4783244 with decreased LVMI, independent of adiponectin and other conventional risk factors. Sleep duration has previously been described as a risk factor for increased LVMI in this population, therefore, we assessed modification of this association in CDH13 by sleep duration, and found that short sleep attenuated the cardio-protective effect of this SNP. Our study provides important insights into pathologic mechanisms and prevention strategies for early risk of cardiovascular disease.

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.

Short Sleep Duration Increases Metabolic Impact in Healthy Adults: A Population-Based Cohort Study

Objectives

The metabolic impact of inadequate sleep has not been determined in healthy individuals outside laboratories. This study aims to investigate the impact of sleep duration on five metabolic syndrome components in a healthy adult cohort.

Methods

A total of 162121 adults aged 20-80 years (men 47.4%) of the MJ Health Database, who were not obese and free from major diseases, were recruited and followed up from 1996 to 2014. Sleep duration and insomnia symptoms were assessed by a self-administered questionnaire. Incident cases of five metabolic syndrome components were identified by follow-up medical examinations. Cox proportional hazard ratios (HRs) were calculated for three sleep duration categories "< 6 hours/day (short)," "6-8 hours/day (regular)," and "> 8 hours/day (long)" with adjustment for potential confounding factors. Analyses were stratified by insomnia symptoms to assess whether insomnia symptoms modified the association between sleep duration and metabolic syndrome.

Results

Compared to regular sleep duration, short sleep significantly (p < .001) increased the risk for central obesity by 12% (adjusted HR 1.12 [1.07-1.17]), for elevated fasting glucose by 6% (adjusted HR 1.06 [1.03-1.09]), for high blood pressure by 8% (adjusted HR 1.08 [1.04-1.13]), for low high-density lipoprotein-cholesterol by 7% (adjusted HR 1.07 [1.03-1.11]), for hypertriglyceridemia by 9% (adjusted HR 1.09 [1.05-1.13]), and for metabolic syndrome by 9% (adjusted HR 1.09 [1.05-1.13]). Long sleep decreased the risk of hypertriglyceridemia (adjusted HR 0.89 [0.84-0.94]) and metabolic syndrome (adjusted HR 0.93 [0.88-0.99]). Insomnia symptoms did not modify the effects of sleep duration.

Conclusions

Sleep duration may be a significant determinant of metabolic health.

Sleep Disturbances as a Risk Factor for Stroke

Sleep, a vital process of human being, is carefully orchestrated by the brain and consists of cyclic transitions between rapid eye movement (REM) and non-REM (NREM) sleep. Autonomic tranquility during NREM sleep is characterized by vagal dominance and stable breathing, providing an opportunity for the cardiovascular-neural axis to restore homeostasis, in response to use, distress or fatigue inflicted during wakefulness. Abrupt irregular swings in sympathovagal balance during REM sleep act as phasic loads on the resting cardiovascular system. Any causes of sleep curtailment or fragmentation such as sleep restriction, sleep apnea, insomnia, periodic limb movements during sleep, and shift work, not only impair cardiovascular restoration but also impose a stress on the cardiovascular system. Sleep disturbances have been reported to play a role in the development of stroke and other cardiovascular disorders. This review aims to provide updated information on the role of abnormal sleep in the development of stroke, to discuss the implications of recent research findings, and to help both stroke clinicians and researchers understand the importance of identification and management of sleep pathology for stroke prevention and care.

Association of sleep duration and quality with blood lipids: a systematic review and meta-analysis of prospective studies

OBJECTIVES

To assess the longitudinal evidence of the relationships between sleep disturbances (of quantity and quality) and dyslipidaemia in the general population and to quantify such relationships.

SETTING

Systematic review and meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

METHODS

We performed a systematic search of PubMed and Embase (up to 9 September 2017), complemented with manual searches, of prospective population studies describing the association between sleep duration and quality and the incidence of dyslipidaemias. Relative risks (95% CIs) were extracted and pooled using a random effects model. Subgroup analyses by lipid type were performed. Heterogeneity and publication bias were also assessed. Quality was assessed with Downs and Black score.

PARTICIPANTS

Studies were included if they were prospective, had measured sleep quantity and/or quality at baseline and either incident cases of dyslipidaemia or changes in blood lipid fractions assessed prospectively.

PRIMARY OUTCOME MEASURES

Incidence of dyslipidaemia and changes in lipid fractions. Dyslipidaemia was defined as a high total cholesterol, triglycerides, low-density lipoprotein cholesterol or low high-density lipoprotein cholesterol compared with the reference group.

RESULTS

Thirteen studies were identified (eight using sleep duration, four sleep quality and one both). There was heterogeneity in the sleep quality aspects and types of lipids assessed. Classification of sleep duration (per hour/groups) also varied widely. In the pooled analysis of sleep duration (6 studies, 16 cohort samples; 30 033 participants; follow-up 2.6-10 years), short sleep was associated with a risk of 1.01 (95% CI 0.93 to 1.10) of developing dyslipidaemia, with moderate heterogeneity (I2=56%, P=0.003) and publication bias (P=0.035). Long sleep was associated with a risk of 0.98 (95% CI 0.87 to 1.10) for dyslipidaemia, with heterogeneity (I2=63%, P<0.001) and no significant publication bias (P=0.248).

CONCLUSION

The present analysis was unable to find supportive evidence of a significant relationship between sleep duration and the development of dyslipidaemia. However, heterogeneity and small number of studies limit the interpretation.

PROSPERO REGISTRATION NUMBER

CRD42016045242.

The association between periodontitis and sleep duration

AIM

Due to its potential to influence systemic inflammation and oxidative stress, and to predispose to bacterial infections, sleep duration could potentially be a risk factor for periodontitis. The aim of this cross-sectional study was to evaluate if there was in 2012 an association between periodontitis and sleep duration in a representative sample of the South Korean population.

MATERIALS AND METHODS

A total of 5812 subjects representative of 39.4 million of adults were examined. Multivariate logistic regressions were applied controlling for age, gender, education, smoking status, alcoholism and consumption frequency of coffee, tea, chocolate and red wine.

RESULTS

Compared to the group sleeping ≤5 h/day, the adjusted odds ratios for periodontitis prevalence defined as Community Periodontal Index (CPI) = 4 were OR = 2.46 (95% CI: 1.20-5.06) in the 6 h/day sleepers group, OR = 2.66 (95% CI: 1.35-5.25) in the 7 h/day sleepers group, OR = 2.29 (95% CI: 1.13-4.63) in the 8 h/day sleepers group and OR = 4.27 (95% CI: 1.83-9.97) in the ≥9 h/day sleepers group. The association has shown to be highlighted in middle-aged people, females, non-smokers, lower educated, with lower lead and higher cadmium blood levels and with higher carotene dietary intake ones and to be partially mediated by lipid profile alterations, diabetes, serum Vitamin D levels and WBC count.

CONCLUSIONS

A novel, direct and independent association between sleep duration and the prevalence of periodontitis was found. However, it needs to be investigated how the factors influencing the sleep duration affect this association.

Sleep duration and risk of stroke: a dose-response meta-analysis of prospective cohort studies

OBJECTIVES

Suboptimal sleep duration has been considered to increase the risk of stroke incidence. Thus we aimed to conduct a dose-response meta-analysis to examine the association between sleep duration and stroke incidence.

METHODS

We searched PubMed, Web of science and the Cochrane Library to identify all prospective studies evaluating the association of sleep duration and nonfatal and/or fatal stroke incidence. Then, restricted cubic spline functions and piecewise linear functions were used to evaluate the nonlinear and linear dose-response association between them.

RESULTS

We included a total of 16 prospective studies enrolling 528,653 participants with 12,193 stroke events. Nonlinear dose-response meta-analysis showed a J-shaped association between sleep duration and total stroke with the lowest risk observed with sleeping for 7 h. Considering people sleeping for 7 h as reference, long sleepers had a higher predicted risk of total stroke than short sleepers [the pooled risk ratios (95% confidence intervals): 4 h: 1.17 (0.99-1.38); 5 h: 1.17 (1.00-1.37); 6 h: 1.10 (1.00-1.21); 8 h: 1.17 (1.07-1.28); 9 h: 1.45 (1.23-1.70); 10 h: 1.64 (1.4-1.92); p_nonlinearity<0.001]. Short sleep durations were only significantly associated with nonfatal stroke and with total stroke in the subgroups of structured interview and non-Asian countries. Additionally, we found a slightly decreased risk of ischemic stroke among short sleepers. For piecewise linear trends, compared to 7 h, every 1-h increment of sleep duration led to an increase of 13% [the pooled risk ratios (95% confidence intervals): 1.13 (1.07-1.20); p < 0.001] in risk of total stroke.

CONCLUSION

Both in nonlinear and piecewise linear dose-response meta-analyses, long sleep duration significantly increased the risk of stroke incidence.

Decrease in Circulating Fatty Acids Is Associated with Islet Dysfunction in Chronically Sleep-Restricted Rats

Previous studies have shown that sleep restriction-induced environmental stress is associated with abnormal metabolism, but the underlying mechanism is poorly understood. In the current study, we investigated the possible lipid and glucose metabolism patterns in chronically sleep-restricted rat. Without changes in food intake, body weight was decreased and energy expenditure was increased in sleep-restricted rats. The effects of chronic sleep disturbance on metabolites in serum were examined using ¹H NMR metabolomics and GC-FID/MS analysis. Six metabolites (lipoproteins, triglycerides, isoleucine, valine, choline, and phosphorylcholine) exhibited significant alteration, and all the fatty acid components were decreased, which suggested fatty acid metabolism was impaired after sleep loss. Moreover, increased blood glucose, reduced serum insulin, decreased glucose tolerance, and impaired glucose-stimulated insulin secretion of islets were also observed in sleep-restricted rats. The islet function of insulin secretion could be partially restored by increasing dietary fat to sleep-disturbed rats suggested that a reduction in circulating fatty acids was related to islet dysfunction under sleep deficiency-induced environmental stress. This study provides a new perspective on the relationship between insufficient sleep and lipid/glucose metabolism, which offers insights into the role of stressful challenges in a healthy lifestyle.

Association of shift-work, daytime napping, and nighttime sleep with cancer incidence and cancer-caused mortality in Dongfeng-tongji cohort study

BACKGROUND

Few studies investigated the combined effects of night-shift work, daytime napping, and nighttime sleep on cancer incidence and mortality.

METHODS

A total of 25,377 participants were included in this study. Information on sleep habits, cancer incidences, and mortalities were collected. Cox proportional hazards models were used to calculate the adjusted hazard ratios and 95% confidence intervals (HRs, 95%CIs).

RESULTS

Male subjects experienced ≥20 years of night-shift work, or without daytime napping had an increased risk of cancer, when compared with males who did not have night-shift work or napped for 1-30 min [HR (95%CI) = 1.27 (1.01-1.59) and 2.03 (1.01-4.13), respectively]. Nighttime sleep for ≥10 h was associated with a separate 40% and 59% increased risk of cancer [HR (95%CI) = 1.40 (1.04-1.88)] and cancer-caused mortality [HR (95%CI) = 1.59 (1.01-2.49)] than sleep for 7-8 h/night. Combined effects of three sleep habits were further identified. Male participants with at least two above risk sleep habits had a 43% increased risk of cancer [HR (95%CI) = 1.43 (1.07-2.01)] and a 2.07-fold increased cancer-caused mortality [HR (95%CI) = 2.07 (1.25-3.29)] than those who did not have any above risk sleep habits. However, no significant associations were observed among women.

CONCLUSIONS

Long night-shift work history, without daytime napping, and long nighttime sleep duration were independently and jointly associated with higher cancer incidence among males. KEY MESSAGES Night-shift work of ≥20 years, without napping, and nighttime sleep of ≥10 h were associated with increased cancer incidence. Nighttime sleep ≥10 h was associated with a 2.07-fold increased cancer-caused mortality among males. Combined effects of night-shift work ≥20 years, without napping, and nighttime sleep ≥10 h on increasing cancer incidence were existed among males.

Changes in sleep duration and risk of metabolic syndrome: the Kailuan prospective study

Using a large longitudinal data set spanning 4 years, we examined whether a change in self-reported sleep duration is associated with metabolic syndrome (MetS). Current analysis included 15,753 participants who were free of MetS during both 2006–2007 and 2010–2011. Sleep duration was categorized into seven groups: ≤5.5 h, 6.0–6.5 h, 7.0 h, 7.5–8.0 h, ≥8.5 h, decrease ≥2 h, and increase ≥2 h. Cox proportional hazards models were used to calculate hazard ratios (HRs) and their confidence intervals (CI) for MetS, according to sleep duration. Compared to the reference group of persistent 7-h sleepers, a decrease of ≥2 h sleep per night was associated with a higher risk of incident MetS (HR = 1.23, 95% CI = 1.05–1.44) in analyses adjusted for age, sex, sleep duration at baseline, marital status, monthly income per family member, education level, smoking status, drinking status, physical activity, body mass index, snoring status and resting heart rate. An increased risk of MetS incidence was also observed in persistent short sleepers (average ≤5.5 h/night; HR = 1.22, 95% CI = 1.01–1.50). This study suggests individuals whose sleep duration decreases ≥2 h per night are at an increased risk of MetS.

Sleep Duration and Midday Napping with 5-Year Incidence and Reversion of Metabolic Syndrome in Middle-Aged and Older Chinese

STUDY OBJECTIVES

Prospective evidence on the association of sleep duration and midday napping with metabolic syndrome (MetS) is limited. We aimed to examine the associations of sleep duration and midday napping with risk of incidence and reversion of MetS and its components among a middle-aged and older Chinese population.

METHODS

We included 14,399 subjects from the Dongfeng-Tongji (DFTJ) Cohort Study (2008-2013) who were free of coronary heart disease, stroke, and cancer at baseline. Baseline data were obtained by questionnaires and health examinations. Odds ratios (ORs) and 95% confidence interval (CI) were derived from multivariate logistic regression models.

RESULTS

After controlling for potential covariates, longer sleep duration (≥ 9 h) was associated with a higher risk of MetS incidence (OR, 1.29; 95% CI, 1.08-1.55) and lower reversion of MetS (OR, 0.80; 95% CI, 0.66-0.96) compared with sleep duration of 7 to < 8 h; whereas shorter sleep duration (< 6 h) was not related to incidence or reversion of MetS. For midday napping, subjects with longer napping (≥ 90 min) was also associated with a higher risk of MetS incidence and a lower risk of MetS reversion compared with those with napping of 1 to < 30 min (OR, 1.48; 95% CI, 1.05-2.10 and OR, 0.70; 95% CI, 0.52-0.94, respectively). Significance for incidence or reversion of certain MetS components remained in shorter and longer sleepers but disappeared across napping categories.

CONCLUSIONS

Both longer sleep duration and longer midday napping were potential risk factors for MetS incidence, and concurrently exert adverse effects on MetS reversion.

Role of sleep quality in the metabolic syndrome

Emerging evidence has assigned an important role to sleep as a modulator of metabolic homeostasis. The impact of variations in sleep duration, sleep-disordered breathing, and chronotype to cardiometabolic function encompasses a wide array of perturbations spanning from obesity, insulin resistance, type 2 diabetes, the metabolic syndrome, and cardiovascular disease risk and mortality in both adults and children. Here, we critically and extensively review the published literature on such important issues and provide a comprehensive overview of the most salient pathophysiologic pathways underlying the links between sleep, sleep disorders, and cardiometabolic functioning.