Differences in insulin secretion and sensitivity in short-sleep insomnia

Dietary patterns and insomnia symptoms: A systematic review and meta-analysis

We aimed to systematically review and synthesize the available evidence regarding the link between dietary patterns and insomnia symptoms among the general population using observational studies. We reviewed 16,455 references, of which 37 studies met inclusion criteria with a total sample size of 591,223. There was a significant association of the Mediterranean diet (OR: 0.86; 95 % CI, 0.79, 0.93; P < 0.001; I2 = 32.68 %), a high-quality diet (OR: 0.66; 95 % CI, 0.48, 0.90; P = 0.010; I2 = 84.62 %), and an empirically-derived healthy dietary pattern (OR: 0.91; 95 % CI, 0.85, 0.98; P = 0.010; I2 = 57.14 %) with a decreased risk of insomnia symptoms. Moreover, the dietary glycemic index (OR: 1.16; 95 % CI, 1.08, 1.25; P < 0.001; I2 = 0.0 %), the dietary glycemic load (OR: 1.10; 95 % CI, 1.01, 1.20; P = 0.032; I2 = 74.36 %), and an empirically-derived unhealthy dietary pattern (OR: 1.20; 95 % CI, 1.01, 1.42; P = 0.040; I2 = 68.38 %) were linked with a higher risk of insomnia symptoms. Most individual studies were of good quality (NOS) but provided very low certainty of evidence (GRADE). Consistent data reveals that following healthy diets is associated with decreased insomnia symptoms prevalence, while adherence to an unhealthy pattern is associated with an increased prevalence of insomnia symptoms.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Insomnia nosology: a systematic review and critical appraisal of historical diagnostic categories and current phenotypes

Insomnia nosology has significantly evolved since the Diagnostic and Statistical Manual (DSM)-III-R first distinguished between 'primary' and 'secondary' insomnia. Prior International Classification of Sleep Disorders (ICSD) nosology 'split' diagnostic phenotypes to address insomnia's heterogeneity and the DSM nosology 'lumped' them into primary insomnia, while both systems assumed causality for insomnia secondary to health conditions. In this systematic review, we discuss the historical phenotypes in prior insomnia nosology, present findings for currently proposed insomnia phenotypes based on more robust approaches, and critically appraise the most relevant ones. Electronic databases PsychINFO, PubMED, Web of Science, and references of eligible articles, were accessed to find diagnostic manuals, literature on insomnia phenotypes, including systematic reviews or meta-analysis, and assessments of the reliability or validity of insomnia diagnoses, identifying 184 articles. The data show that previous insomnia diagnoses lacked reliability and validity, leading current DSM-5-TR and ICSD-3 nosology to 'lump' phenotypes into a single diagnosis comorbid with health conditions. However, at least two new, robust insomnia phenotyping approaches were identified. One approach is multidimensional-multimethod and provides evidence for self-reported insomnia with objective short versus normal sleep duration linked to clinically relevant outcomes, while the other is multidimensional and provides evidence for two to five clusters (phenotypes) based on self-reported trait, state, and/or life-history data. Some approaches still need replication to better support whether their findings identify true phenotypes or simply different patterns of symptomatology. Regardless, these phenotyping efforts aim at improving insomnia nosology both as a classification system and as a mechanism to guide treatment.

Investigating the shared genetic architecture and causal relationship between pain and neuropsychiatric disorders

Pain often occurs in parallel with neuropsychiatric disorders. However, the underlying mechanisms and potential causality have not been well studied. We collected the genome-wide association study (GWAS) summary statistics of 26 common pain and neuropsychiatric disorders with sample size ranging from 17,310 to 482,730 in European population. The genetic correlation between pair of pain and neuropsychiatric disorders, as well as the relevant cell types were investigated by linkage disequilibrium (LD) score regression analyses. Then, transcriptome-wide association study (TWAS) was applied to identify the potential shared genes by integrating the gene expression information and GWAS. In addition, Mendelian randomization (MR) analyses were conducted to infer the potential causality between pain and neuropsychiatric disorders. Among the 169 pairwise pain and neuropsychiatric disorders, 55 pairs showed positive correlations (median r_g = 0.43) and 9 pairs showed negative correlations (median r_g =  -0.31). Using MR analyses, 26 likely causal associations were identified, including that neuroticism and insomnia were risk factors for most of short-term pain, and multisite chronic pain was risk factor for neuroticism, insomnia, major depressive disorder and attention deficit/hyperactivity disorder, and vice versa. The signals of pain and neuropsychiatric disorders tended to be enriched in the functional regions of cell types from central nervous system (CNS). A total of 19 genes shared in at least one pain and neuropsychiatric disorder pair were identified by TWAS, including AMT, NCOA6, and UNC45A, which involved in glycine degradation, insulin secretion, and cell proliferation, respectively. Our findings provided the evidence of shared genetic structure, causality and potential shared pathogenic mechanisms between pain and neuropsychiatric disorders, and enhanced our understanding of the comorbidities of pain and neuropsychiatric disorders.

The impact of insomnia on frailty and the hallmarks of aging

Throughout the course of life, there are age-related changes in sleep. Despite these normal changes, there is a high percentage of older adults that report sleep dissatisfaction with a high pervasiveness of chronic insomnia, the most common sleep disorder worldwide, with its prevalence being expected to continuously increase due to the growing rates of aging and obesity. This can have different adverse health outcomes, especially by promoting both physical and cognitive decline, which ultimately may aggravate frailty in older adults. Moreover, age-related frailty and sleep dysfunction may have a common mechanism related to the hallmarks of cellular aging. Cellular aging was categorized into nine hallmarks, such as DNA damage, telomere attrition and epigenetic changes. In the context of geriatric and chronic insomnia research, this review aims at discussing the current evidence from both animal models and human cohorts addressing the link between chronic insomnia, the hallmarks of aging and their impact on frailty. Moreover, the most recent research about the putative effect of insomnia therapeutic approaches on hallmarks of aging will be also highlighted.

Effects of Dietary Carbohydrate Profile on Nocturnal Metabolism, Sleep, and Wellbeing: A Review

Sleep is a crucial biological function and a well-established driver of health and wellbeing across the lifespan. In this review, we describe how sleep in humans is associated with specific circadian metabolic and physiological changes, and how the organization of sleep-wake states is related to regulation of nocturnal metabolism during fasting. Among the modifiable factors that can contribute to sleep-related benefits, emerging evidence suggests that diet and nocturnal changes in glucose regulation are strong determinants of sleep quality. Here, we review studies that have explored the importance of quantity and quality of dietary carbohydrates and proteins in modulation of sleep and sleep-related health benefits. Future research may guide the creation of nutritional solutions to improve sleep, which could lead to positive changes in health, wellbeing, and overall quality of life.

Association of insomnia and short sleep duration, alone or with comorbid obstructive sleep apnea, and the risk of chronic kidney disease

STUDY OBJECTIVES

Obstructive sleep apnea (OSA), sleep fragmentation, and short sleep duration (SD) have been associated with chronic kidney disease (CKD). However, these potential mechanisms for CKD have not been compared in the same cohort. This study investigated the independent and combined impact of OSA and insomnia with short sleep duration on the risk of CKD progression in a sleep clinic population.

METHODS

In a cross-sectional study design, adults with suspected OSA completed an overnight sleep study and a questionnaire that included the Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI). They also provided blood and urine samples for measurement of the glomerular filtration rate and urine albumin:creatinine ratio, from which the risk of CKD progression was determined.

RESULTS

Participants (n = 732, 41% female, 55 ± 13 years) were categorized into four groups: no/mild OSA without insomnia (NM-OSA, n = 203), insomnia with SD without OSA (Insomnia-SD, n = 104), moderate-to-severe OSA without insomnia (MS-OSA, n = 242), and comorbid insomnia and OSA with SD (COMISA-SD, n = 183). After stratification, 12.8% of NM-OSA, 15.4% of Insomnia-SD, 28.9% of MS-OSA, and 31.7% of the COMISA-SD participants had an increased risk of CKD progression. Compared to NM-OSA, the odds ratio (OR) for an increased risk of CKD progression was not increased in Insomnia-SD (OR 0.95, confidence interval [CI]: 0.45-1.99) and was increased to the same degree in MS-OSA (OR 2.79, CI: 1.60-4.85) and COMISA-SD (OR 3.04, CI: 1.69-5.47). However, the ORs were similar between the MS-OSA and COMISA-SD groups across all statistical models (p ≥ .883).

CONCLUSIONS

In a sleep clinic population, insomnia with short sleep duration does not increase the risk of CKD progression; nor does it further increase the risk of CKD progression associated with moderate-to-severe OSA.

Understanding insomnia as systemic disease

Sleep plays a critical role in homeostasis of the body and mind. Insomnia is a disease that causes disturbances in the initiation and maintenance of sleep. Insomnia is known to affect not only the sleep process itself but also an individual’s cognitive function and emotional regulation during the daytime. It increases the risk of various neuropsychiatric diseases such as depression, anxiety disorder, and dementia. Although it might appear that insomnia only affects the nervous system, it is also a systemic disease that affects several aspects of the body, such as the cardiovascular, endocrine, and immune systems; therefore, it increases the risk of various diseases such as hypertension, diabetes mellitus, and infection. Insomnia has a wide range of effects on our bodies because sleep is a complex and active process. However, a high proportion of patients with insomnia do not seek treatment, which results in high direct and indirect costs. This is attributed to the disregard of many of the negative effects of insomnia. Therefore, we expect that understanding insomnia as a systemic disease will provide an opportunity to understand the condition better and help prevent secondary impairment due to insomnia.

Acute sleep loss alters circulating fibroblast growth factor 21 levels in humans: A randomised crossover trial

The hormone fibroblast growth factor 21 (FGF21) modulates tissue metabolism and circulates at higher levels in metabolic conditions associated with chronic sleep-wake disruption, such as type 2 diabetes and obesity. In the present study, we investigated whether acute sleep loss impacts circulating levels of FGF21 and tissue-specific production, and response pathways linked to FGF21. A total of 15 healthy normal-weight young men participated in a randomised crossover study with two conditions, sleep loss versus an 8.5-hr sleep window. The evening before each intervention, fasting blood was collected. Fasting, post-intervention morning skeletal muscle and adipose tissue samples underwent quantitative polymerase chain reaction and DNA methylation analyses, and serum FGF21 levels were measured before and after an oral glucose tolerance test. Serum levels of FGF21 were higher after sleep loss compared with sleep, both under fasting conditions and following glucose intake (~27%-30%, p = 0.023). Fasting circulating levels of fibroblast activation protein, a protein which can degrade circulating FGF21, were not altered by sleep loss, whereas DNA methylation in the FGF21 promoter region increased only in adipose tissue. However, even though specifically the muscle exhibited transcriptional changes indicating adverse alterations to redox and metabolic homeostasis, no tissue-based changes were observed in expression of FGF21, its receptors, or selected signalling targets, in response to sleep loss. In summary, we found that acute sleep loss resulted in increased circulating levels of FGF21 in healthy young men, which may occur independent of a tissue-based stress response in metabolic peripheral tissues. Further studies may decipher whether changes in FGF21 signalling after sleep loss modulate metabolic outcomes associated with sleep or circadian disruption.

Insomnia with objective short sleep duration is associated with cognitive impairment: a first look at cardiometabolic contributors to brain health

STUDY OBJECTIVES

Insomnia with objective short sleep duration has been previously associated with adverse cardiometabolic health outcomes as well as poorer cognitive performance in otherwise noncognitively impaired adults. However, studies demonstrating an increased prevalence of cognitive impairment (CI) in this insomnia phenotype are lacking.

METHODS

We analyzed data from Penn State Adult Cohort (N = 1,524; 48.9 ± 13.4 years; 53.4% women). Self-reported sleep difficulty was defined as normal sleep (n = 899), poor sleep (n = 453), and chronic insomnia (n = 172). Objective short sleep duration was defined as less than 6-h of sleep, based on in-lab, 8-h polysomnography. CI (n = 155) and possible vascular cognitive impairment (pVCI, n = 122) were ascertained using a comprehensive neuropsychological battery. Analyses adjusted for age, sex, race, education, body mass index, apnea/hypopnea index, smoking, alcohol, psychoactive medication, and mental and physical health problems.

RESULTS

Participants who reported poor sleep or chronic insomnia and slept objectively less than 6 hours were associated with a 2-fold increased odds of CI (OR = 2.06, 95% confidence limits [CL] = 1.15-3.66 and OR = 2.18, 95% CL = 1.07-4.47, respectively) and of pVCI (OR = 1.94, 95% CL = 1.01-3.75 and OR = 2.33, 95% CL = 1.07-5.06, respectively). Participants who reported poor sleep or chronic insomnia and slept objectively more than 6 hours were not associated with increased odds of either CI (OR = 0.72, 95% CL = 0.30-1.76 and OR = 0.75, 95% CL = 0.21-2.71, respectively) or pVCI (OR = 1.08, 95% CL = 0.42-2.74 and OR = 0.76, 95% CL = 0.16-3.57, respectively).

CONCLUSIONS

Insomnia with objective short sleep duration is associated with an increased prevalence of CI, particularly as it relates to cardiometabolic health (i.e. pVCI). These data further support that this insomnia phenotype may be a more biologically severe form of the disorder associated with cardiovascular, cerebrovascular, and neurocognitive morbidity.

The association of insomnia disorder characterised by objective short sleep duration with hypertension, diabetes and body mass index: A systematic review and meta-analysis

Insomnia disorder with objective short sleep duration (less than 6 h of objective sleep or sleep efficiency less than 85%) has been considered as a biologically severe subtype of insomnia associated with a higher risk of cardiometabolic disease morbidity. This systematic review and meta-analysis firstly compared insomnia disorder with objective short and normal sleep duration, and subsequently, objective short sleep duration with and without insomnia disorder, and their associations with hypertension, type 2 diabetes and body mass index. A systematic search of five databases yielded 2345 non-duplicated articles, of which 11 individual studies were used for the qualitative review and 10 individual studies for the meta-analysis. The sample size varied from 30 to 4994 participants. A higher risk of hypertension (RR 1.54, 95% CI: [1.30; 1.82] p < 0.0001) and type 2 diabetes (RR 1.63 [1.37; 1.94], p < 0.0001) was associated with insomnia disorder with objective short sleep compared to normal sleep duration, but not for body mass index. Comparisons between insomnia disorder with objective short sleep and objective short sleep without insomnia disorder showed no significant differences. However, the majority of these studies were cross-sectional, and there is a need for more cohort study data.

Interplay of Objective Sleep Duration and Cardiovascular and Cerebrovascular Diseases on Cause-Specific Mortality

Background Cardiovascular and cerebrovascular diseases (CBVDs) and cancer are leading causes of death. Short sleep is a potential contributor to health; however, its role in predicting mortality associated with cardiometabolic risk factors (CMRs) and CBVD remains poorly understood. We tested whether objective short sleep duration increases the risk of mortality associated with CMRs and CBVD. Methods and Results A total of 1654 adults (aged 20-74 years) from the Penn State Adult Cohort (47.5 years, 52.5% women, and 89.8% white) whose cause of death was determined after 19.2 years (5.2 years). CMR was defined as stage 2 hypertension and/or type 2 diabetes mellitus on the basis of blood pressure and glucose levels or a report of diagnosis or treatment for these conditions. CBVD was defined as a report of diagnosis or treatment for heart disease and/or stroke. Objective short sleep duration was defined as polysomnographic total sleep time <6 hours. Cox proportional hazard models estimated multivariable-adjusted hazard ratios (HRs) and 95% CIs. Risk of all-cause mortality associated with CMR or CBVD was significantly modified by objective sleep duration (P<0.05), and it was significantly higher in subjects who slept <6 hours (HR, 2.14 [95% CI, 1.52-3.02] and HR, 3.17 [95% CI=2.16-4.65], respectively). In subjects who slept <6 hours, CMR was associated with a 1.83 higher (95% CI, 1.07-3.13) risk of CBVD mortality and CBVD with a 2.92 higher (95% CI, 1.28-6.65) risk of cancer mortality. In subjects who slept ≥6 hours, CMR was not significantly associated with CBVD mortality (HR, 1.35; 95% CI, 0.70-2.63) nor was CBVD significantly associated with cancer mortality (HR, 0.55; 95% CI, 0.18-1.64). Conclusions Objective short sleep duration predicts the all-cause mortality prognosis of middle-aged adults with CMR and the cancer-specific mortality prognosis of those with CBVD.

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

Study Objectives

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

Methods

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

Results

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

Conclusions

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

Poor Sleep Quality is Associated with Insulin Resistance in Postmenopausal Women With and Without Metabolic Syndrome

BACKGROUND

Poor sleep quality has previously been shown to be related to insulin resistance in apparently healthy adults. However, it is unclear whether an association between sleep quality and insulin resistance exists among adults with metabolic syndrome (MetS).

METHODS

Participants included 347 overweight/obese postmenopausal women without type 2 diabetes (age: 57.5 ± 6.5 years; body mass index [BMI]: 31.7 ± 3.7 kg/m²; 54% with MetS). Sleep quality was assessed with the six-item Medical Outcomes Study Sleep Scale; values were categorized into quartiles. Insulin resistance was calculated from fasting glucose and insulin with the homeostasis model assessment of insulin resistance (HOMA2-IR) method. Analysis of covariance models were used to examine the association between sleep quality and HOMA2-IR after accounting for MetS and covariates (e.g., BMI, cardiorespiratory fitness, and energy intake).

RESULTS

Women with the worst sleep quality had significantly higher HOMA2-IR values than women in all other quartiles (P ≤ 0.05 for each), and women with MetS had significantly higher HOMA2-IR values than women without MetS (P < 0.0001), but the relationship between sleep quality and HOMA2-IR did not differ between those with or without MetS (P = 0.26). Women with MetS in the worst quartile of sleep quality had higher HOMA2-IR values than all other women (P < 0.02). Taking >30 min to fall asleep, frequent restless sleep, and frequent daytime drowsiness were each related to higher HOMA2-IR values (each P < 0.04).

CONCLUSIONS

Sleep quality is an important correlate of insulin resistance in postmenopausal women with and without MetS. Intervention studies are needed to determine whether improving sleep improves insulin resistance in populations at elevated cardiometabolic risk.

Objective short sleep duration modifies the relationship between hypertension and all-cause mortality

OBJECTIVE

Short sleep duration has been associated with cardiovascular morbidity and mortality. However, previous studies were limited by using subjective sleep measures and treating sleep duration as a sole, independent predictor. Therefore, the role of sleep duration in predicting mortality is still not well understood. We posit that objective sleep duration is an effect modifier of the relationship between hypertension and all-cause mortality.

METHODS

We addressed this question in the Penn State Adult Cohort, a random, general population sample of 1741 men and women (48.7 ± 13.5 years) who were studied in the sleep laboratory and followed up for 15.5 ± 4.1 years. Hypertension was defined on the basis of SBP and DBP (≥140/≥90 mmHg) or use of antihypertensive medication. Polysomnographic sleep duration was classified into three clinically meaningful categories.

RESULTS

We tested the interaction between hypertension and polysomnographic sleep duration on all-cause mortality using multiple logistic regression while controlling for several potential confounders (P value = 0.03). The odds (95% confidence interval) of all-cause mortality associated with hypertension were 1.77 (1.07-2.92), 2.78 (1.47-5.24), and 3.93 (2.22-6.95) for individuals who slept at least 6, 5-6, and 5 h or less, respectively.

CONCLUSION

The risk of mortality associated with hypertension increases in a dose-response manner as a function of shorter sleep duration. Short sleep in hypertensive individuals may be a marker of the degree of central autonomic dysfunction. Future epidemiological studies should examine this effect modification using cause-specific mortality, whereas future clinical trials should examine whether lengthening sleep improves the prognosis of individuals with hypertension.

Impact of the Metabolic Syndrome on Mortality is Modified by Objective Short Sleep Duration

BACKGROUND

To examine whether objective sleep duration is an effect modifier of the impact of metabolic syndrome (MetS) on all-cause and cardiovascular disease/cerebrovascular mortality.

METHODS AND RESULTS

We addressed this question in the Penn State Adult Cohort, a random, general population sample of 1344 men and women (48.8±14.2 years) who were studied in the sleep laboratory and followed up for 16.6±4.2 years. MetS was defined by the presence of 3 or more of obesity (≥30 kg/m2), elevated total cholesterol (≥200 mg/dL), triglycerides (≥150 mg/dL), fasting glucose (≥100 mg/dL), and blood pressure (≥130/85 mm Hg). Polysomnographic sleep duration was classified into clinically meaningful categories. Among the 1344 participants, 22.0% of them died during the follow-up. We tested the interaction between MetS and polysomnographic sleep duration on mortality using Cox proportional hazard models controlling for multiple potential confounders (P<0.05). The hazard ratios (95% CI) of all-cause and cardiovascular disease/cerebrovascular mortality associated with MetS were 1.29 (0.89-1.87) and 1.49 (0.75-2.97) for individuals who slept ≥6 hours and 1.99 (1.53-2.59) and 2.10 (1.39-3.16) for individuals who slept <6 hours. Interestingly, this effect modification was primarily driven by the elevated blood pressure and glucose dysregulation components of MetS.

CONCLUSIONS

The risk of mortality associated with MetS is increased in those with short sleep duration. Short sleep in individuals with MetS may be linked to greater central autonomic and metabolic dysfunction. Future clinical trials should examine whether lengthening sleep improves the prognosis of individuals with MetS.

Lack of change in glucose metabolism in eszopiclone-treated primary insomnia patients

STUDY OBJECTIVES

Primary insomnia (PI) may increase diabetes risk. We tested the hypothesis that the effects of PI on glucose metabolism could be improved by 2 months of pharmacological treatment.

METHODS

Adult men and women meeting clinical criteria for PI were studied (n=20, body mass index 25.1±2.7 kg/m², age 39.7±7.9) in a randomized, double-blind, placebo-controlled clinical trial. The study consisted of two 1-day inpatient admissions to a General Clinical Research Center separated by 2 months of at-home treatment with 3 mg eszopiclone or placebo. During inpatient admissions, each subject underwent two intravenous glucose tolerance tests (IVGTTs) pre- and post-treatment. Diet was controlled for micro- and macro-nutrient content and calories on the day prior to pre- and post-treatment IVGTTs. Subjects were randomized following completion of the initial IVGTT to take either placebo or eszopiclone 30 min prior to bedtime at home for 2 months.

RESULTS

Two-month eszopiclone treatment did not change insulin sensitivity, glucose tolerance, or any of the sleep measures significantly, compared with placebo. Changes in glycated hemoglobin (HbA1c, clinical measure of glycemic control) were correlated with changes in diary-reported total sleep time in the eszopiclone group (r=0.66, p=0.0360), and in the combined groups' data (r=0.55, p=0.0125). Changes in polysomnography-measured wake after sleep onset, a hallmark of PI, were positively related to changes in IVGTT-derived glucose effectiveness, or non-insulin-mediated glucose uptake.

CONCLUSION

Treatment with 3 mg eszopiclone for 2 months, compared with placebo, did not significantly influence either sleep or measures of diabetes risk in this preliminary study.

Insomnia and incident depression: role of objective sleep duration and natural history

Longitudinal studies that have examined the association of insomnia with incident depression using objective sleep measures are very limited. The aim of this study was to examine the predictive role of the severity of insomnia for incident depression in a general population sample using psychometric and polysomnographic data. From a random, general population sample of 1741 individuals of the Penn State Adult Cohort, 1137 adults without depression were followed up with a structured telephone interview after 7.5 years. All subjects completed a full medical evaluation, 1-night polysomnogram and Multiphasic Minnesota Personality Inventory at baseline. The incidence of depression was 15%. Poor sleep (odds ratio = 1.5, P = 0.001) and insomnia (odds ratio = 1.9, P = 0.031) were significantly associated with incident depression. The odds of incident depression were highest (odds ratio = 2.2, P = 0.019) in insomnia with objective short sleep duration and independent of Multiphasic Minnesota Personality Inventory Ego Strength scores, an index of poor coping resources. The persistence of insomnia and worsening of poor sleep into insomnia significantly increased the odds of incident depression (odds ratios ranged from 1.8 to 6.3), whereas their full remission did not (odds ratio ranged from 1.2 to 1.8). Insomnia with short sleep duration is associated with incident depression independent of poor coping resources, whereas the association of insomnia with normal sleep duration with incident depression was mediated by poor coping resources. Persistence and worsening of poor sleep or insomnia, but not their full remission, are significant predictors of incident depression. These data suggest that there is a significant relationship between the severity of insomnia and incident depression.

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.