Sleep symptoms predict the development of the metabolic syndrome

Enduring sleep complaints predict health problems: a six-year follow-up of the survey of health and retirement in Europe

OBJECTIVES

Sleep complaints are common and enduring among old people. The study aimed to extend current knowledge by exploring the effects of episodic versus chronic sleep complaints on a range of physical and mental health outcomes.

METHODS

Older adults (N = 8934, mean age = 64) who participated in Waves 1, 2 and 4 of the Survey of Health, Ageing and Retirement in Europe (SHARE) reported sleep and health outcome measures. Episodic sleep complaints, in the first or in the second wave and chronic sleep complaints, in both waves were recorded. Outcomes in Wave 4 included physical symptoms, difficulties in activities of daily living and low quality of life.

RESULTS

Logistic regressions examined whether episodic and chronic sleep complaints at W1 and W2 predict W4 health outcomes. Chronic sleep complaints predicted worse outcomes, compared to no sleep difficulties and to episodic sleep complaints, even after adjusting for demographic characteristics and previous levels of health.

CONCLUSION

Sleep complaints and mainly chronic sleep complaints are related to elevated risk of future health and functional problems. Caregivers are encouraged to address sleep complaints and provide their older patients with help before sleep complaints become persistent.

Association Between Nonrestorative Sleep and Risk of Diabetes: A Cross-Sectional Study

Although insufficient sleep or poor sleep quality has been reported to be associated with the development of type 2 diabetes, the relation of type 2 diabetes with nonrestorative sleep (NRS), a subjective feeling, has been overlooked. We used a large-scale medical checkup database to investigate whether there is a cross-sectional association between NRS and type 2 diabetes risk in Japanese individuals. We extracted data for 14,476 individuals who were not receiving therapeutic drugs for diabetes. About 36.8% of individuals were identified as having NRS. In a multiple logistic regression analysis, NRS was significantly associated with the risk of developing diabetes. Thus, this line of research may have implications for diabetes prevention.

Frequency of Loud Snoring and Metabolic Syndrome among Korean Adults: Results from the Health Examinees (HEXA) Study

Studies regarding the association between snoring and metabolic abnormalities have been inconsistent. We examine whether snoring frequency and obstructive sleep apnea markers are associated with metabolic syndrome (MetS) among Koreans aged 40-69 years. A total of 72,885 subjects (24,856 men, 48,029 women) from the Health Examinees Gem study between 2009 and 2013 were included. Snoring frequency was grouped into five categories (never, 1-3/month, 1-3/week, 4-5/week, 6+/week). Obstructive sleep apnea markers included breathing interruptions and awakenings. Adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated through logistic regression. Compared with non-snorers, those who snore 6+/week were associated with increased odds for MetS (OR: 2.07, 95% CI: 1.91-2.25, p-trend < 0.0001 among men; OR: 1.45, CI: 1.33-1.58, p-trend < 0.0001 among women). Snoring frequency is associated with MetS and its components in both men and women. Snoring and obstructive sleep apnea markers are important indicators of sleep quality, which may facilitate early detection of sleep disorders and further complications such as MetS.

Association between Insomnia and Metabolic Syndrome in a Chinese Han Population: A Cross-sectional Study

The association between insomnia and metabolic syndrome remains unclear, especially among different-aged groups. A cross-sectional study with 8017 participants was performed to identify whether insomnia was associated with metabolic syndrome or not. Demographic characteristics, lifestyles and other risk factors were collected using a predesigned, semi-structured, self-administered questionnaire, and physical examinations were conducted by certificated community physicians. Insomnia was not independently associated with metabolic syndrome across all subjects; however, the association between insomnia and metabolic syndrome was statistically significant in the male group (odds ratio (OR): 1.35, 95% confidence interval (CI): 1.02–1.77) and the middle-aged group (OR: 1.40, 95% CI: 1.09–1.79) but not in the female group, the young adult group or the older group. Analyses of the individual components of metabolic syndrome revealed that insomnia was independently associated with raised blood pressure (OR: 1.24, 95% CI: 1.05–1.43) and low high-density lipoprotein cholesterol (HDL-c) (OR: 1.16, 95% CI: 1.01–1.33). Insomnia was also independently associated with the severity of metabolic abnormalities (OR: 1.17, 95% CI: 1.03–1.32). This study demonstrates an independent association between insomnia and metabolic syndrome in males and middle-aged participants, which suggests that treatment for insomnia will contribute to the prevention of metabolic syndrome in males and the middle-aged population.

[Foshouningshen decoction improves sleeping via the serotonergic system in a rat model of insomnia]

OBJECTIVE

To evaluate the sedative and hypnotic effects of Foshouningshen decoction (FSNSD) and study its effects on expressions of 5-hydroxy tryptamine (5-HT) and 5-HT1A receptor (5-HT_1AR) in the hippocampus in a rat model of insomnia.

METHODS

Male KM mice were divided into control group, estazolam (0.4 mg/kg daily) group, and low-, moderate-, and high-dose FSNSD groups (daily dose of 12, 24, and 48 g/kg, respectively). After corresponding treatments for 1 week, the mice underwent sleep-inducing test with subthreshold and threshold doses of sodium pentobarbital. Forty-eight male SD rats were randomized into control group, insomnia model group, estazolam group (0.2 mg/kg daily), and low-, moderate-, and high-dose FSNSD groups (with daily dose of 6, 12, and 24 g/kg, respectively). Rat models of insomnia were established by intraperitoneal injection of 4-cholro-dl-phenylalanine (PCPA) at the daily dose of 350 mg/kg for 3 days, after which the rats received corresponding treatments via gavage for 1 week. The performance of the rats in open field test was recorded and the hippocampal expression of 5-HT was detected using ELISA; the expressions of 5-HT_1AR protein and mRNA in the hippocampus were detected using immunohistochemistry and real-time PCR, respectively.

RESULTS

In the sleep-inducing test with a subthreshold dose of sodium pentobarbital, the mice treated with high-dose FSNSD showed a significantly higher rate of sleep onset than the control mice (P<0.05); in the test with a threshold dose of sodium pentobarbital, treatment with moderate- and high-dose FSNSD resulted in significantly prolonged sleeping time (P<0.01) and shortened sleep latency (P<0.05) in the mice. The rats in insomnia model group showed increased total distance in open field test (P<0.05) with significantly decreased content of 5-HT (P<0.01) and expressions of 5-HT_1AR protein and mRNA in the hippocampus (P<0.01). Treatment of the rats with estazolam or high-dose FSNSD obviously decreased the total distance in open field test (P<0.05) and increased the content of 5-HT (P<0.05) and expressions of 5-HT_1AR (P<0.01) in the hippocampus of rats with insomnia.

CONCLUSION

FSNSD can produce therapeutic effects on insomnia possibly by increasing 5-HT content and expressions of 5-HT_1AR in the hippocampus.

Relationship between stress coping and sleep disorders among the general Japanese population: a nationwide representative survey

OBJECTIVE

To clarify the prevalence of stress, and examine the relationship between sleep disorders and stress coping strategies among highly stressed individuals in the general Japanese population.

METHODS

A cross-sectional nationwide survey was undertaken in November 2007. Men and women were randomly selected from 300 districts throughout Japan. Data from 7671 (3532 men (average age 53.5 ± 17.0 years) and 4139 women (average age 53.9 ± 17.7 years)) were analyzed. Participants completed a self-reported questionnaire on stress, sleep disorders, and stress coping strategies in the previous month.

RESULTS

Highly stressed individuals comprised 16.6% (95% confidence interval 15.8-17.5%) of the total sample, and most were aged 20-49 years. In multiple logistic regression, symptoms of insomnia (ie, difficulty initiating sleep, difficulty maintaining sleep, and early morning awakening), excessive daytime sleepiness, nightmares, daytime malfunction, and lack of rest due to sleep deprivation were more prone to occur in highly stressed individuals. In addition, logistic regression analysis controlling for other adjustment factors revealed that stress coping strategies such as 'giving up on problem-solving', 'enduring problems patiently', 'smoking' and 'drinking alcohol' were positively associated with the above-mentioned sleep disorders. On the other hand, stress coping strategies such as 'exercising', 'enjoying hobbies', and 'sharing worries' were inversely associated with the above-mentioned sleep disorders.

CONCLUSIONS

Distraction-based stress coping (eg, hobbies, exercise, and optimistic thinking) was found to be preferable to problem-based stress coping in a highly stressed Japanese general population.

Effects of a Serotonin 2C Agonist and a 2A Antagonist on Actigraphy-Based Sleep Parameters Disrupted by Methamphetamine Self-Administration in Rhesus Monkeys

Sleep disorders and substance abuse are highly comorbid and we have previously shown that methamphetamine self-administration significantly disrupts activity-based sleep parameters in rhesus monkeys. To the best of our knowledge, no study has evaluated the effectiveness of any pharmacological intervention to attenuate the effects of methamphetamine on nighttime activity under well-controlled conditions in laboratory animals. Thus, we examined the effects of a 5-HT_2C receptor agonist, WAY163909, and a 5-HT_2A receptor antagonist, M100907, given alone and in combination, on actigraphy-based sleep parameters disrupted by methamphetamine self-administration in non-human primates. Adult male/female rhesus monkeys self-administered methamphetamine (0.03 mg/kg/injection, i.v.) under a fixed-ratio 20 schedule of reinforcement (60-min sessions once a day, 5 days per week). Nighttime activity was evaluated using Actiwatch monitors. WAY163909 (0.1, 0.3, and 1.0 mg/kg), M100907 (0.03, 0.1, and 0.3 mg/kg), and a combination (0.1 mg/kg M100+0.3 mg/kg WAY) were administered i.m. before lights-out. Each dose was given for five consecutive days during which self-administration took place in the morning. Both drugs improved activity-based sleep measures disrupted by methamphetamine by decreasing sleep latency and increasing sleep efficiency compared with vehicle. By combining these drugs, their individual effects were significantly enhanced. Agonists at the 5-HT_2C receptor and antagonists at the 5-HT_2A receptor show promise as potential treatments for the sleep-disrupting effects of stimulants when used alone and in combination. Combining subthreshold doses of WAY and M100 produced significant improvements in nighttime activity measures while avoiding the general motor-decreasing effects of the high dose of WAY.

Association between Self-reported Snoring and Prediabetes among Adults Aged 40 Years and Older without Diabetes

BACKGROUND

Several previous studies have shown that snoring is associated with glucose metabolism and the development of diabetes, but rare study has shown the association between snoring frequency and prediabetes, particularly in China. We hypothesized that individuals who snore might have a higher risk of prediabetes. This study aimed to investigate the association between self-reported snoring and prediabetes in a Chinese population.

METHODS

A cross-sectional study was performed in three large communities of Beijing from December 2011 to August 2012 by recruiting individuals aged ≥40 years old. All participants were requested to complete a detailed questionnaire and undergo anthropometric measurements. A 75 g oral glucose tolerance test was performed in individuals without diabetes. Blood samples of all participants were collected; blood glucose and blood fat levels were measured. Multivariate logistic regression models were built to assess the association between snoring frequency and prediabetes.

RESULTS

A total of 13,592 participants (female: 66.56%; mean age: 56.8 ± 7.9 years; mean body mass index: 25.5 ± 3.4 kg/m2) were included in the final analysis. Of these, 30.9% were diagnosed with prediabetes, while 41.3% and 25.4% had occasional and habitual snoring, respectively. Habitual snoring was associated with an increased risk of prediabetes (odds ratio [OR]: 1.3, 95% confidence interval [CI]: 1.1-1.4, P< 0.001), after adjusting for diabetes and sleep-related confounders in the multivariable models. Habitual snoring was also associated with isolated impaired fasting glucose (IFG; OR: 1.3, 95% CI: 1.0-1.6; P< 0.001) and isolated impaired glucose tolerance (IGT; OR: 1.3, 95% CI: 1.2-1.5; P< 0.001), but not IFG + IGT (OR: 1.1, 95% CI: 0.9-1.4; P = 0.281). When stratified by total cholesterol (TC) levels, this association between habitual snoring and prediabetes was observed only in individuals with TC <5.6 mmol/L (OR: 1.4, 95% CI: 1.2-1.6; P< 0.001).

CONCLUSIONS

Habitual snoring is associated with prediabetes, but only in individuals with TC <5.6 mmol/L. Further prospective studies are needed to confirm this finding.

Support vector machines for automated snoring detection: proof-of-concept

BACKGROUND

Snoring has been shown to be associated with adverse physical and mental health, independent of the effects of sleep disordered breathing. Despite increasing evidence for the risks of snoring, few studies on sleep and health include objective measures of snoring. One reason for this methodological limitation is the difficulty of quantifying snoring. Conventional methods may rely on manual scoring of snore events by trained human scorers, but this process is both time- and labor-intensive, making the measurement of objective snoring impractical for large or multi-night studies.

METHODS

The current study is a proof-of-concept to validate the use of support vector machines (SVM), a form of machine learning, for the automated scoring of an objective snoring signal. An SVM algorithm was trained and tested on a set of approximately 150,000 snoring and non-snoring data segments, and F-scores for SVM performance compared to visual scoring performance were calculated using the Wilcoxon signed rank test for paired data.

RESULTS

The ability of the SVM algorithm to discriminate snore from non-snore segments of data did not differ statistically from visual scorer performance (SVM F-score = 82.46 ± 7.93 versus average visual F-score = 88.35 ± 4.61, p = 0.2786), supporting SVM snore classification ability comparable to visual scorers.

CONCLUSION

In this proof-of-concept, we established that the SVM algorithm performs comparably to trained visual scorers, supporting the use of SVM for automated snoring detection in future studies.

Cognitive and affective functions associated with insomnia: a population-based study

OBJECTIVES

The number of patients with insomnia is rapidly increasing as society ages. The influence of insomnia on cognitive, affective, and activities of daily living (ADL) functions has not been fully studied.

METHODS

Participants were 142 residents of a local super-aged community who underwent health check-ups provided by the local government. Participants completed cognitive, affective and ADL function tests including the MMSE. We divided participants into two subgroups based on Athens Insomnia Scale (AIS) scores (AIS ≤3 and AIS ≥4) and compared cognitive, affective, and ADL functions by sex and age.

RESULTS

Subjective insomnia (AIS ≥4) was found in 36.2% of participants and was more frequent in females than males. No differences were found in cognitive function between the AIS subgroups. For both sexes, Geriatric Depression Scale scores were significantly higher in the AIS ≥4 subgroup than the AIS ≤3 subgroup. Apathy Scale scores were significantly higher in males in the AIS ≥4 subgroup. Of the AIS subscales, 'sleepiness during the day' was significantly higher in females than males (**p < 0.01), especially in those aged  ≥75 years (**p < 0.01). This group of older females also showed a significantly lower Trail Making Test scores (*p < 0.05).

DISCUSSION

Insomnia was present in 36.2% of the population in a Japanese super-aged community. Those with insomnia showed more depressive symptoms (both sexes) and males showed more apathy. The most distinct characteristic of females aged  ≥75 years was a high frequency of daytime sleepiness, possibly related to a decline in attention and executive function.

Self-Reported Snoring Is Associated with Dyslipidemia, High Total Cholesterol, and High Low-Density Lipoprotein Cholesterol in Obesity: A Cross-Sectional Study from a Rural Area of China

Studies to explore the relationship between self-reported snoring and dyslipidemia, especially high total cholesterol (TC) and high low-density lipoprotein cholesterol (LDL-C), in the general population are still lacking. Our study was designed to examine whether self-reported snoring is significantly associated with dyslipidemia and ascertain the effects of different snoring intensities on dyslipidemia. There were 10,139 participants in our study. After adjustment for all confounding factors, self-reported snoring (OR = 1.207; p = 0.003), moderate (OR = 1.229; p = 0.015), strong (OR = 1.222; p = 0.033), and very strong (OR = 1.467; p = 0.012) snoring intensity, but not low (OR = 1.110; p = 0.224) snoring intensity, were significantly associated with dyslipidemia among adults with BMI (body mass index) ≥ 25 kg/m². In addition, self-reported snoring was significantly associated with high TC (OR = 1.167; p = 0.048) and high LDL-C (OR = 1.228; p = 0.044), rather than low HDL-C (OR = 1.171; p = 0.057) and high triglyceride (TG) (OR = 1.110; p = 0.141). In conclusion, adults with BMI ≥ 25 kg/m² and who experience snoring, especially moderate, strong, and very strong intensity levels of snoring, should be on the alert regarding the possibility of dyslipidemia, especially high LDL-C and high TC.

Does Improving Marital Quality Improve Sleep? Results From a Marital Therapy Trial

For most adults, sleep is a dyadic behavior. Only recently have studies explored the dynamic association between sleep and relationship functioning among bed partners. The current study is the first to examine bidirectional associations between changes in insomnia and changes in marital quality over time, in the context of a marital therapy trial. Among husbands, improvements in marital satisfaction were associated with a 36% decreased risk of insomnia at follow-up. Regarding the reverse direction, counter-intuitively, wife baseline insomnia was associated with improvements in husbands' marital satisfaction, but only among the non-treatment-seeking comparison group. Results are discussed in terms of implications for sleep and marital therapy, and suggest that improving sleep may be an added benefit of improving the marital relationship.

Insomnia and obesity

PURPOSE OF REVIEW

Accumulating data suggest that short sleep plays a role in the development of obesity in general population. Insomnia disorder is characterized by short sleep and may persist for years. The question whether these patients have a higher risk of obesity is of socioeconomic as well as therapeutic interest.

RECENT FINDINGS

Numerous recently published cross-sectional and longitudinal studies show positive as well as negative associations between short sleep and overweight. Critical reviews note several methodological limitations that weaken the assumption of short sleep duration as the potential cause for obesity. From a sleep medical perspective, a basic methodological problem is the lack of a biological cut-off for short sleep duration. Therefore, recent findings on the relation between emotional stress in short sleepers and incident of obesity opens a more promising perspective on sleep quality as a possible factor. A few studies on patients with insomnia disorder, however, do not show higher BMIs adding data to a research puzzle.

SUMMARY

The relation of sleep duration and incident obesity so far has insufficient evidence base. Few data on patients with insomnia disorder do not confirm the association. Further research is necessary with focus on sleep quality instead of sleep duration.

Obstructive sleep apnea predicts risk of metabolic syndrome independently of obesity: a meta-analysis

INTRODUCTION

Obstructive sleep apnea (OSA) has been suggested to be associated with a high risk of metabolic syndrome (MS). However, results on whether the association between OSA and risk of MS is independent of obesity, and the effect of nocturnal intermittent hypoxia (IH) on MS, are conflicting. Our purpose was to estimate the magnitude of the independent association between OSA and risk of MS and further explore whether nocturnal IH in OSA plays a role in MS risk.

MATERIAL AND METHODS

The PubMed and EMBASE databases were systematically searched (until January 21, 2015) for available observational evidence. Unadjusted and body mass index (BMI)-adjusted pooled odds ratios (ORs) for MS in OSA or higher nocturnal IH were calculated using fixed or random models. Tests of homogeneity, publication bias, and robustness of the results were performed.

RESULTS

A total of 13 independent studies (involving 857 participants in 3 case-control studies and 7077 participants in 10 cross-sectional studies) were included. The OSA was significantly associated with an increased risk of MS in a meta-analysis of 10 studies (pooled OR = 1.72, 95% CI: 1.31-2.26, p < 0.001), with a BMI-adjusted pooled OR of 1.97 (95% CI: 1.34-2.88, p < 0.001). Pooled results from 3 studies on the oxygen desaturation index (ODI) and MS risk (OR = 1.96, 95% CI: 1.73-2.22, p < 0.001) and 3 studies on the cumulative percentage of sleep time with SpO₂ below 90% (CT90) and MS risk (OR = 1.05, 95% CI: 1.02-1.07, p < 0.001) were also significant.

CONCLUSIONS

Our findings demonstrated a significant association between OSA and increased MS risk independent of BMI, and further indicated a role of nocturnal IH in this association.

Effects of chronic sleep deprivation on bone mass and bone metabolism in rats

BACKGROUND

This study aimed to assess the effects of chronic sleep deprivation (CSD) on bone mass and bone metabolism in rats.

METHODS

Twenty-four rats were randomly divided into CSD and control (CON) groups. Rats were subjected to CSD by using the modified multiple platform method (MMPM) to establish an animal model of CSD. Biochemical parameters such as levels of serum N-terminal propeptide of type I procollagen (PINP), N-terminal cross-linking telopeptide of type I collagen (NTX), growth hormone (GH), estradiol (E2), serum 25(OH)D, and calcium (Ca) were evaluated at 0, 1, 2, and 3 months. After 3 months, each fourth lumbar vertebra and the distal femoral metaphysis of the left extremity of rats were harvested for micro-computed tomography scans and histological analysis, respectively, after the rats were sacrificed under an overdose of pentobarbital sodium.

RESULTS

Compared with rats from the CON group, rats from the CSD group showed significant decreases in bone mineral density (BMD), bone volume over total volume, trabecular bone thickness, and trabecular bone number and significant increases in bone surface area over bone volume and trabecular bone separations (P < 0.05). Bone histomorphology studies showed that rats in the CSD group had decreased osteogenesis, impaired mineralization of newly formed bones, and deteriorative trabecular bone in the secondary spongiosa zone. In addition, they showed significantly decreased levels of serum PINP (1 month later) and NTX (3 months later) (P < 0.05). The serum 25(OH)D level of rats from the CSD group was lower than that of rats from the CON group after 1 month (P < 0.05).

CONCLUSIONS

CSD markedly affects bone health by decreasing BMD and 25(OH)D, deteriorating the bone microarchitecture, and decreasing bone formation and bone resorption markers.

Probable insomnia is associated with future total energy intake and diet quality in men

BACKGROUND

Insomnia is associated with several adverse health outcomes. Small clinical studies have suggested that an inferior nutrition status is a potential explanation, but to our knowledge, this possibility has not been examined in a large-scale, population-based cohort study.

OBJECTIVE

We examined whether individuals with probable insomnia and individual insomnia symptoms had greater energy intake and a lower diet quality as assessed with the use of the Alternate Healthy Eating Index (AHEI) 2 y later.

DESIGN

A cohort study of 15,273 US men aged 58-93 y who were free of cancer, cardiovascular diseases, and diabetes and were participating in the Health Professionals Follow-Up Study reported information on insomnia symptoms in 2004. Dietary intake was assessed with the use of a food-frequency questionnaire in 2002 and 2006. We calculated the adjusted mean differences of total energy intake in 2006 and the AHEI-component scores and their 95% CIs between subjects with and without probable insomnia in 2004 and also across categories for each insomnia symptom while adjusting for related covariates.

RESULTS

After dietary intake in 2002, major chronic conditions, and other potential confounders were controlled for, men with probable insomnia had a mean higher consumption of 35.8 kcal/d (95% CI: 17.4, 54.1 kcal/d) and had lower scores in 3 individual AHEI components (trans fat, vegetables, and sodium), which denoted higher consumption of trans fat and sodium and lower intake of vegetables (P ≤ 0.01 for all). For individual insomnia symptoms, nonrestorative sleep and a difficulty maintaining sleep were associated with higher energy intake (P-trend ≤ 0.007 for both). A similar trend was observed in men who had difficulty initiating sleep (P-trend = 0.07). We also observed a significant association between the difficulty of initiating sleep and a lower AHEI score 2 y later (P-trend = 0.004).

CONCLUSION

Probable insomnia is associated with higher intakes of total energy, trans fat, and sodium and lower intake of vegetables.

The Link of Self-Reported Insomnia Symptoms and Sleep Duration with Metabolic Syndrome: A Chinese Population-Based Study

STUDY OBJECTIVES

The aims of this study are to investigate the relationships of metabolic syndrome (MetS) with insomnia symptoms and sleep duration in a Chinese adult population.

METHODS

Data from a nationwide epidemiological survey conducted on residents from randomly selected districts in Taiwan in 2007 were used for this cross-sectional population-based study. A total of 4,197 participants were included in this study. Insomnia symptoms, including difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), early morning awakening (EMA), were assessed using the Insomnia Self-Assessment Inventory questionnaire. Subjects were divided into 3 groups based upon their reported sleep duration (< 7, 7-8, and ≥ 9 h per night). Odds ratios (ORs) and 95% confidence intervals (CIs) derived from multivariable logistic regression were used to evaluate the study aims.

RESULTS

The endorsement of DIS and DMS were cross-sectionally associated with the MetS after adjustment for sleep duration (OR [95% CI] was 1.24 [1.01-1.51] and 1.28 [1.02-1.61], respectively). In addition, short sleep duration was significantly associated with the prevalence of MetS independent of insomnia symptoms (OR [95% CI] was 1.54 [1.05-2.47]). However, there was no significant combined effect of insomnia symptoms and sleep duration on the prevalence of MetS.

CONCLUSIONS

The current investigation shows that short sleep duration and insomnia symptoms, specifically DIS and DMS, were significant correlates of MetS. These findings should be replicated in prospective studies using both sleep duration and sleep quality measures.

Effects of chronic sleep deprivation on glucose homeostasis in rats

Epidemiological studies have shown that chronic sleep disturbances resulted in metabolic disorders. The purpose of this study was to assess the relationship between chronic sleep deprivation (CSD) and the glucose homeostasis in rats. Twenty-four rats were randomly divided into CSD group and control (CON) group. The CSD rats were intervened by a modified multiple platform method (MMPM) to establish an animal model of chronic sleep disturbances. After 3-month intervention, all rats were subjected to an intraperitoneal glucose tolerance test (IPGTT) and an insulin tolerance test (ITT), and the body weight, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, lipid profile group, and homeostasis model assessment-IR (HOMA-IR) were measured. Both the CSD and CON groups had an attenuation of weight gain after 3-month intervention. The plasma glucose level of CSD group was higher than that of the CON group during the IPGTT (P < 0.01). The CSD rats showed a marked increase in HOMA-IR and ITT compared with the CON group (P < 0.01). There were no significant differences of AST, ALT, creatinine, and most lipid parameters between the CSD and CON groups (P > 0.05). The CSD has a marked effect on glucose homeostasis, comprising glucose intolerance and insulin resistance.

Effects of aerobic exercise on home-based sleep among overweight and obese men with chronic insomnia symptoms: a randomized controlled trial

OBJECTIVE

To determine the effect of a six-month aerobic exercise program on home-based sleep quality among overweight and obese men with chronic insomnia symptoms.

METHODS

Participants were 45 Finnish men (93% had body mass index ≥25) aged 30-65 years, with chronic (≥3 months) insomnia symptoms as classified by the DSM-IV criteria. Participants were randomized into an exercise (n = 24) or control group (n = 21). The exercise group received six-month aerobic exercise intervention with one to five sessions per week of 30-60 minutes duration. The control group was instructed to maintain habitual lifestyle behaviors during the study period. Seven-night home sleep was measured with a piezoelectric bed sensor and sleep diary. Other assessments included the modified Basic Nordic Sleep Questionnaire, a health and behavior questionnaire, physical activity and diet diaries, anthropometry, fat mass, and physical fitness. Analysis of covariance controlling for baseline values, and repeated-measures analysis of variance were implemented for time-by-group comparisons and within-group comparisons, respectively.

RESULTS

At six months, the exercise group showed reduced objective sleep onset latency (p = 0.010) and lowered frequency of difficulty initiating sleep (p = 0.021) than controls. Although a time-by-group difference was not significant, exercisers showed shorter objective wake after sleep onset (p = 0.004), reduced subjective nocturnal awakenings (p = 0.010), improved objective sleep efficiency (p <0.001), and improved morning-rated subjective sleep quality (p = 0.042) at six months than baseline.

CONCLUSIONS

A six-month aerobic exercise can improve sleep, mainly by mitigating difficulty of initiating sleep among overweight and obese men with chronic insomnia symptoms.

Insomnia symptoms and heart rate recovery among patients in cardiac rehabilitation

Insomnia symptoms (i.e., difficulty falling asleep, difficulty staying asleep, and early morning awakenings) are common among people with cardiovascular disease, and have been linked to adverse cardiovascular health outcomes. Reduced parasympathetic tone is one pathway through which risk may be conferred. The purpose of this study was to evaluate whether insomnia symptoms are associated with lower parasympathetic tone in cardiac rehabilitation patients with suspected insomnia. Participants (N = 121) completed a self-report measure of insomnia severity. 1-min heart rate recovery (HRR), an index of parasympathetic tone, was obtained during a maximal exercise test. Difficulty falling asleep, but not difficulty staying asleep or early awakenings, was associated with attenuated 1-min HRR. When analyses were restricted to participants with moderate and severe insomnia severity (n = 51), the strength of this association increased. In a sample of cardiac rehabilitation patients with insomnia, only the symptom of difficulty falling asleep was associated with lower parasympathetic tone, suggesting that individual insomnia symptoms may show specificity in their associations with physiological mechanisms.

Study of Sedative-Hypnotic Effects of Aloe vera L. Aqueous Extract through Behavioral Evaluations and EEG Recording in Rats

In this study, we investigated the sedative and hypnotic effects of the aqueous extract of Aloe vera on rats. In order to evaluate the overall hypnotic effects of the Aloe vera extract, open field and loss of righting reflex tests were primarily used. The sedative and hypnotic effects of the extract were then confirmed by detection of remarkable raise in the total sleeping time through analysis of electroencephalographic (EEG) recordings of animals. Analysis of the EEG recordings showed that there is concomitant change in Rapid Eye Movement (REM) and None Rapid Eye Movement (NREM) sleep in parallel with the prolonged total sleeping time. Results of the current research show that the extract has sedative-hypnotic effects on both functional and electrical activities of the brain.

Social Jetlag, Chronotype, and Cardiometabolic Risk

CONTEXT

Shift work, which imposes a habitual disruption in the circadian system, has been linked to increased incidence of cardiometabolic diseases, and acute circadian misalignment alters various metabolic processes. However, it remains unclear whether day-to-day circadian dysregulation contributes to these risks beyond poor sleep and other behavioral characteristics.

OBJECTIVE

Individuals differ in circadian phase preference, known as chronotype, but may be constrained by modern work obligations to specific sleep schedules. Individuals experience social jetlag (SJL) due to a habitual discrepancy between their endogenous circadian rhythm and actual sleep times imposed by social obligations. Here, we examined whether chronotype and/or SJL associate with components of cardiovascular disease risk beyond the known effects of sleep disturbances, poor health behaviors, and depressive symptomatology.

DESIGN

Participants were healthy, midlife adults who worked part- or full-time day shifts (n = 447; mean age, 42.7 [range, 30-54] y; 53% female; 83% white). Chronotype was assessed with the Composite Scale of Morningness. SJL was quantified as the difference (in minutes) between the midpoints of actigraphy-derived sleep intervals before work vs non-workdays.

RESULTS

Multiple regression analyses showed that SJL related to a lower high-density lipoprotein-cholesterol level, higher triglycerides, higher fasting plasma insulin, insulin resistance, and adiposity (P < .05), even after adjustment for subjective sleep quality, actigraphy-derived sleep characteristics, depressive symptomatology, and health behaviors. Evening chronotype associated with lower high-density lipoprotein-cholesterol after adjustment for covariates.

CONCLUSION

Our findings suggest that a misalignment of sleep timing is associated with metabolic risk factors that predispose to diabetes and atherosclerotic cardiovascular disease.

Sleep complaints and metabolic syndrome in an elderly population: the Three-City Study

OBJECTIVES

To assess whether sleep complaints (rather than clinically defined sleep disturbances) were associated with the metabolic syndrome (MetS) and each of its components in an elderly population.

METHODS

Cross-sectional analyses of data from the French Three City Study, a large multicenter cohort of elderly community-dwellers.

PARTICIPANTS

6,354 participants (56.4% women, median age 73; range: 65-97 years).

MEASUREMENTS

Frequency of insomnia complaints (difficulty in initiating sleep, difficulty in maintaining sleep [DMS], and early morning awakening) and excessive daytime sleepiness (EDS) were self-reported. MetS was assessed using National Cholesterol Education program Adult Treatment Panel III criteria.

RESULTS

A total of 977 participants had MetS. After adjustment for a large range of potential confounders, we report an association between the number of insomnia complaints and MetS. Among insomnia complaints only DMS was consistently associated with MetS (OR: 1.23, 95% CI: 1.06 to 1.43). Our results showed that EDS independently increased the risk of MetS (OR: 1.46, 95% CI: 1.18 to 1.81 for "frequently"; OR: 1.99, 95% CI: 1.49 to 1.67 for "often"). The EDS-MetS association was independent of past-history of cardiovascular disease, insomnia complaints, and obesity and loud snoring.

CONCLUSION

We report significant independent associations between frequent sleep complaints (EDS and to a lesser extent DMS) and MetS in the elderly with potential implications in terms of management and cardiovascular prevention in general geriatric practice. Prospective studies are required to clarify the direction of the association between sleep complaints and MetS.

The Role of Trauma Type in the Risk for Insomnia

OBJECTIVE

Insomnia is common following exposure to trauma and can occur independently or as a feature of posttraumatic stress disorder (PTSD). However, there is limited research identifying risk factors associated with the development of insomnia following exposure to a traumatic event. The goal of this study was to evaluate the role of specific trauma types in the risk for insomnia in a community sample of urban African Americans young adults.

METHODS

A sample of 554 nonclinical, urban, young adult African Americans was recruited for a larger study from which 465 participants were utilized for this study based on their completion of all study self-report measures. Participants were initially screened by phone to determine whether they provisionally met study criteria. Once selected, participants underwent informed consent and then completed a battery of self-report measures that included the Life Events Checklist, the PTSD Checklist, the Insomnia Severity Index, and the Fear of Sleep Index.

RESULTS

Of the seven trauma categories that were endorsed by at least 20% of the sample, results from logistic regression models indicated that sexual trauma, physical assault, accidents, natural disasters, and sudden violent death predicted insomnia independent of sex. However, PTSD symptom severity and nocturnal fears differentially influenced the relationship between trauma type and risk for insomnia.

CONCLUSIONS

Exposure to specific types of trauma increases the odds of insomnia twofold to threefold. Additionally, PTSD symptom severity and nocturnal fears contribute differentially to the relationship between trauma exposure and insomnia suggesting the possibility of multiple underlying pathways.

Metabolic risk factors and posttraumatic stress disorder: the role of sleep in young, healthy adults

OBJECTIVE

Posttraumatic stress disorder (PTSD) is associated with indicators of poor physical health and sleep disturbance. This study investigated the relationship between PTSD and metabolic risk factors and examined the role of sleep duration in medically healthy and medication-free adults.

METHODS

Participants with PTSD (n = 44, mean age = 30.6 years) and control participants free of lifetime psychiatric history (n = 50, mean age = 30.3 years) recorded sleep using sleep diary for 10 nights and actigraphy for 7 nights. We assessed metabolic risk factors including fasting triglycerides, total cholesterol, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein cholesterol, as well as abdominal fat using dual-energy x-ray absorptiometry.

RESULTS

PTSD was associated with shorter sleep duration (based on self-report, not actigraphy) and higher metabolic risks (controlling for body fat percentage), including increased triglycerides (p = .03), total cholesterol (p < .001), LDL cholesterol (p = .006), very low density lipoprotein cholesterol (p = .002), and cholesterol/high-density lipoprotein ratio (p = .024). In addition, sleep duration was associated with metabolic risks in PTSD (significant correlations ranged from r = -0.20 to r = -0.40) but did not fully account for the association between PTSD and metabolic measures.

CONCLUSIONS

Metabolic risk factors are associated with PTSD even in early adulthood, which highlights the need for early intervention. Future longitudinal research should assess whether sleep disturbance in PTSD is a mechanism that contributes to heightened metabolic risk to elucidate the pathway from PTSD to higher rates of medical disorders such as obesity, diabetes, and heart disease.

Sleep and multisystem biological risk: a population-based study

Background

Short sleep and poor sleep quality are associated with risk of cardiovascular disease, diabetes, cancer, and mortality. This study examines the contribution of sleep duration and sleep quality on a multisystem biological risk index that is known to be associated with morbidity and mortality.

Methods

Analyses include a population-based sample from the Midlife Development in the United States survey recruited to the Biomarker substudy. A total of 1,023 participants aged 54.5 years (SD = 11.8), 56% female and 77.6% white, were included in the analyses. A multisystem biological risk index was derived from 22 biomarkers capturing cardiovascular, immune, lipid-metabolic, glucose-metabolic, sympathetic, parasympathetic, and hypothalamic-pituitary-adrenal systems. Self-reported average sleep duration was categorized as short (<5 hrs), below normal (5 to <6.5 hrs), normal (6.5 to <8.5 hrs), and long sleepers (8.5+ hrs). Sleep quality was determined using the Pittsburgh Sleep Quality Index categorized as normal (≤5) and poor quality (>5) sleep.

Findings

Linear mixed effect models adjusting for age, gender, race, education, income, BMI, and health status were performed. As compared to normal sleepers, multisystem biological risk in both short (B(SE) = .38(.15), p<.01) and long sleepers (B(SE) = .28(.11), p<.01) were elevated. Poor quality sleep alone was associated with elevated multisystem biological risk (B(SE) = .15(.06), p = .01), but was not significant after adjustment for health status. All short sleepers reported poor sleep quality. However in the long sleepers, only those who reported poor sleep quality exhibited elevated multisystem biological risk (B(SE) = .93(.3), p = .002).

Conclusions

Self-reported poor sleep quality with either short or long sleep duration is associated with dysregulation in physiological set points across regulatory systems, leading to elevated multisystem biological risk. Physicians should inquire about sleep health in the assessment of lifestyle factors related to disease risk, with evidence that healthy sleep is associated with lower multisystem biological risk.

Associations of exercise, sedentary time and insomnia with metabolic syndrome in Taiwanese older adults: A 1-year follow-up study

BACKGROUND

Understanding the risk factors of metabolic syndrome (MetS) is important to public health, since individuals with MetS have an increased risk of health problems. This study examined the associations of exercise, sedentary time and insomnia with incident MetS among older adults 1 year later.

METHOD

A total of 1,359 older adults receiving hospital health examinations in 2012 were studied, and 779 subjects had a follow-up after 1 year. The components of MetS (waist, blood pressure, high-density lipoprotein cholesterol, fasting glucose and triglyceride) were defined by the Program's Adult Treatment Panel III report. Exercise, sedentary time and insomnia data were obtained through self-report questionnaires. Physical fitness (body fatness, balance and hand grip strength) was measured. Two logistic regressions were computed to examine the associations of exercise/physical fitness, sedentary time and insomnia at baseline with incident MetS 1 year later. The first regression included age, sex, smoking and alcohol as covariates. The second regression was further adjusted with the components of MetS.

RESULTS

Sex, exercise/balance, sedentary time and insomnia were significant predictors of MetS. The risk of MetS incidence was 3.36 (95% CI 1.96-5.77) for women, 1.92 (95% CI 1.01-3.63) for those who did not exercise, 2.52 (95% CI 1.37-4.63) for those who sat more than 5 h/day, and 2.17 (95% CI 1.13-4.15) for those with insomnia. Poor balance was significantly associated with greater risk of MetS (AOR = 1.07, 95% CI 1.02-1.12). Sex, sedentary time, insomnia and balance remained significant after adjusting with the components of MetS.

CONCLUSIONS

Cultivating exercise habits, reducing sedentary time and improving sleep quality may be important strategies for MetS prevention among older adults.

Prevalence of dyslipidemia and its association with insomnia in a community based population in China

Background

Studies of the prevalence of dyslipidemia and its association with insomnia are scarce in China. This study investigated the prevalence of dyslipidemia and its association with insomnia in a community based Chinese population.

Methods

We conducted a cross-sectional survey in Beijing and recruited 10054 participants aged ≥18 years. The association between self-reported insomnia and dyslipidemia was determined by multiple logistic regression models. Age, gender, education, obesity, body mass index, physical activity, current smoking, current drinking, diabetes, and hypertension were adjusted as confounders. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were reported as effect measurements.

Results

The prevalence of dyslipidemia in those with no insomnia, occasional insomnia, and frequent insomnia were 53.3%, 54.3%, and 54.5% in men and 52.0%, 54.8%, and 61.2% in women. Compared with subjects with no insomnia, the multivariate adjusted ORs and 95% CIs for those with occasional insomnia and frequent insomnia were 1.07(0.86 ~ 1.34) and 1.19(0.89 ~ 1.60) for men, and 1.00(0.86 ~ 1.14) and 1.23(1.03 ~ 1.47) for women.

Conclusions

These observations indicate that frequent insomnia was associated with a higher prevalence of dyslipidemia in women. This association was not significant in men.

The mediating effect of sleep quality on the relationship between PTSD and physical activity

STUDY OBJECTIVES

Physical inactivity is linked to health outcomes such as obesity, diabetes, and psychiatric disorders. Sleep disturbance has been linked to the same adverse outcomes. We examine the influence of sleep on physical activity as a novel approach to understand these relationships. Specifically, our objective was to determine whether low sleep quality predicts low physical activity in posttraumatic stress disorder (PTSD), a disorder associated with sleep disturbance, physical inactivity, and poor health outcomes.

METHODS

We used data from the Mind Your Heart Study, a prospective cohort study of 736 outpatients recruited from two Department of Veterans Affairs (VA) medical centers. We assessed PTSD with the Clinician Administered PTSD Scale, sleep quality using an item from the Pittsburgh Sleep Quality Index, and physical activity by self-report at baseline and again one year later. Hierarchical multiple regression models and structural equation modeling were used to examine the relationships among PTSD, sleep, and physical activity.

RESULTS

Sleep quality but not PTSD status was prospectively associated with lower physical activity in a model adjusting for age, sex, apnea probability, depression, body mass index, and baseline physical activity (β = 0.129, SE = 0.072, p < 0.01). Structural equation modeling indicated that the results were consistent with sleep quality statistically mediating the relationship between PTSD status at baseline and physical activity one year later.

CONCLUSIONS

Worse sleep quality predicts lower physical activity in PTSD, providing possible evidence for a behavioral pathway from disturbed sleep to poor physical health outcomes.

The hypocretin/orexin system: an increasingly important role in neuropsychiatry

Hypocretins, also named as orexins, are excitatory neuropeptides secreted by neurons specifically located in lateral hypothalamus and perifornical areas. Orexinergic fibers are extensively distributed in various brain regions and involved in a number of physiological functions, such as arousal, cognition, stress, appetite, and metabolism. Arousal is the most important function of orexin system as dysfunction of orexin signaling leads to narcolepsy. In addition to narcolepsy, orexin dysfunction is associated with serious neural disorders, including addiction, depression, and anxiety. However, some results linking orexin with these disorders are still contradictory, which may result from differences of detection methods or the precision of tools used in measurements; strategies targeted to orexin system (e.g., antagonists to orexin receptors, gene delivery, and cell transplantation) are promising new tools for treatment of neuropsychiatric disorders, though studies are still in a stage of preclinical or clinical research.

Metabolic consequences of sleep and circadian disorders

Sleep and circadian rhythms modulate or control daily physiological patterns with importance for normal metabolic health. Sleep deficiencies associated with insufficient sleep schedules, insomnia with short-sleep duration, sleep apnea, narcolepsy, circadian misalignment, shift work, night eating syndrome, and sleep-related eating disorder may all contribute to metabolic dysregulation. Sleep deficiencies and circadian disruption associated with metabolic dysregulation may contribute to weight gain, obesity, and type 2 diabetes potentially by altering timing and amount of food intake, disrupting energy balance, inflammation, impairing glucose tolerance, and insulin sensitivity. Given the rapidly increasing prevalence of metabolic diseases, it is important to recognize the role of sleep and circadian disruption in the development, progression, and morbidity of metabolic disease. Some findings indicate sleep treatments and countermeasures improve metabolic health, but future clinical research investigating prevention and treatment of chronic metabolic disorders through treatment of sleep and circadian disruption is needed.

Daytime sleepiness and risk of coronary heart disease and stroke: results from the Nurses' Health Study II

OBJECTIVE

The objective of this study was to determine whether daytime sleepiness is independently associated with coronary heart disease (CHD) and stroke or whether the positive association is explained by short sleep duration, disturbed sleep, and circadian disruption, conditions that are associated with cardiometabolic risk factors for vascular events.

METHODS

Longitudinal analyses of data from the Nurses' Health Study II comprising 84,003 female registered nurses aged 37-54 at baseline were conducted in 2001 with follow-up until 2009. Multivariate Cox regression was used to explore the relationship between reported daytime sleepiness and the incidence of either CHD or stroke (n=500 cases).

RESULTS

Women who reported daytime sleepiness almost every day, compared with rarely/never, had an elevated adjusted risk of cardiovascular disease (CVD) (hazard ratio (HR)=1.58, 95% confidence interval (CI) 1.15-2.17). Controlling for sleep variables (sleep duration, snoring, shift work, and sleep adequacy) or potential metabolic biological mediators of disrupted sleep (diabetes, hypercholesterolemia, and hypertension) appreciably attenuated the relationship (HR=1.17, 95% CI 0.84-1.65; and HR=1.34, 95% CI 0.97-1.85, respectively). Controlling for both sleep variables and metabolic risk factors eliminated an independent association (HR=1.09, 95% CI 0.77-1.53). A similar pattern was observed for CHD and stroke individually.

CONCLUSIONS

Daytime sleepiness was not an independent risk factor for CVD in this cohort of women, but rather, was associated with sleep characteristics and metabolic abnormalities that are risk factors for CVD.

Self-reported habitual snoring and risk of cardiovascular disease and all-cause mortality

OBJECTIVE

Inconsistent findings have reported the association between self-reported habitual snoring and risk of cardiovascular disease (CVD) and all-cause mortality. We conducted a meta-analysis to investigate whether self-reported habitual snoring was an independent predictor for CVD and all-cause mortality using prospective observational studies.

METHODS

Electronic literature databases (PubMed, Medline, Embase, Cochrane Library, Wanfang database, and China National Knowledge Infrastructure) were searched for publications prior to September 2013. Only prospective studies evaluating baseline habitual snoring and subsequent risk of CVD and all-cause mortality were selected. Pooled adjust hazard risk (HR) and corresponding 95% confidence intervals (CI) were calculated for categorical risk estimates.

RESULTS

Eight studies with 65,037 subjects were analyzed. Pooled adjust HR was 1.26 (95% CI 0.98-1.62) for CVD, 1.15 (95% CI 1.05-1.27) for coronary heart disease (CHD), and 1.26 (95% CI 1.11-1.43) for stroke comparing habitual snoring to non-snorers. Pooled adjust HR was 0.98 (95% CI 0.78-1.23) for all-cause mortality in a random effect model comparing habitual snoring to non-snorers. Habitual snoring appeared to increase greater stroke risk among men (HR 1.54; 95% CI: 1.09-2.17) than those in women (HR 1.22; 95% CI: 1.05-1.41).

CONCLUSIONS

Self-reported habitual snoring is a mild but statistically significant risk factor for stroke and CHD, but not for CVD and all-cause mortality. However, whether the risk is attributable to obstructive sleep apnea syndrome or snoring alone remains controversial.