Sleep duration is associated with dyslipidemia in patients with bipolar disorder in clinical remission

Demographic, clinical and biochemical correlates of the length of stay for different polarities in Chinese inpatients with bipolar disorder: A real-world study

Introduction: Many patients with bipolar disorder (BD) need hospitalization, while the number of hospital beds for these patients is limited. Managing the length of stay (LOS) is an effective solution to this issue. Research on LOS and its influencing factors in BD is limited in China. This study aimed to identify the factors relevant to LOS in different polarities in Chinese patients with BD. Method: This was a real-world, cross-sectional study. Data were obtained from the electronic medical record system. Patients admitted to Beijing Anding Hospital between Jan 2014 and Dec 2017 and diagnosed with BD were included. Demographic information, clinical characteristics, and biochemical variables were collected. Patients were classified into short and long LOS groups based on a cutoff value. A univariate study and a multivariate logistic regression analysis were performed to identify variables related to LOS in various BD polarities. The receiver operating characteristic (ROC) analysis was utilized to evaluate the discrimination accuracy of the regression model. Result: Four thousand six hundred and seventy-five visits from 4,451 individuals were included in the analysis. For the whole sample, unmarried status, psychotic features, and family history of mental disorders were positively associated with long LOS (all p < 0.05). There was an additive interaction between a family history of mental disorders and polarities (p < 0.05). For manic episodes, unmarried status, psychotic features, and family history of mental disorders were positively associated with long LOS (all p < 0.05). For depressive episodes, psychotic features and high-density lipoprotein cholesterol (HDLC) levels were positively associated with long LOS (all p < 0.05). For mixed states, unmarried status was positively associated with long LOS, while low-density lipoprotein cholesterol (LDLC) levels were negatively associated with LOS (all p < 0.05). The area under the curve (AUC) values for depressive episodes, manic episodes, and mixed states in the combined model were 0.587, 0.553, and 0.619, respectively (all p < 0.05). Discussion: The findings suggested that LOS correlates differed by polarity, with marital status, psychotic features, a family history of mental disorders, and lipid levels strongly linked with LOS in patients with BD.

Elevated lipids are associated with reduced regional brain structure in youth with bipolar disorder

OBJECTIVE

Abnormal blood lipid levels are common in bipolar disorder (BD) and correlate with mood symptoms and neurocognition. However, studies have not examined the lipid-brain structure association in BD or youth.

METHODS

This study examined low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), triglycerides, and total cholesterol (TC) levels in relation to brain structure utilizing T1-weighted images, among participants ages 13-20 with BD (n = 55) and healthy controls (HC; n = 47). General linear models investigated group differences in the association of lipids with anterior cingulate cortex (ACC), hippocampus, and inferior parietal lobe structure, controlling for age, sex, body mass index, and intracranial volume. For significant associations, post hoc within-group analyses were undertaken. Exploratory vertex-wise analyses further investigated group differences in the lipid-brain structure association.

RESULTS

There were significant group differences in the association of LDL-C (β = -0.29 p = 0.001), and TC (β = -0.21 p = 0.016), with hippocampal volume, and triglycerides with ACC volume (β = -0.25 p = 0.01) and area (β = -0.26 p = 0.004). Elevated lipids were associated with smaller brain structure to a significantly greater extent in BD vs HC. Post hoc analyses revealed that elevated LDL-C (β = -0.27 p = 0.007) and reduced HDL-C (β = 0.24 p = 0.01) were associated with smaller hippocampal volume in the BD group. Exclusion of BD second-generation antipsychotic users did not alter these results. Vertex-wise analyses further showed that elevated lipids were associated with smaller brain structure to a significantly greater extent in BD vs HC, across the cortex.

CONCLUSION

Elevated lipids are associated with smaller brain structure in BD. Research evaluating lipid-brain structure associations prospectively and whether lipid optimization has salutary effects on brain structure is necessary.

Circadian depression: A mood disorder phenotype

Major mood syndromes are among the most common and disabling mental disorders. However, a lack of clear delineation of their underlying pathophysiological mechanisms is a major barrier to prevention and optimised treatments. Dysfunction of the 24-h circadian system is a candidate mechanism that has genetic, behavioural, and neurobiological links to mood syndromes. Here, we outline evidence for a new clinical phenotype, which we have called 'circadian depression'. We propose that key clinical characteristics of circadian depression include disrupted 24-h sleep-wake cycles, reduced motor activity, low subjective energy, and weight gain. The illness course includes early age-of-onset, phenomena suggestive of bipolarity (defined by bidirectional associations between objective motor and subjective energy/mood states), poor response to conventional antidepressant medications, and concurrent cardiometabolic and inflammatory disturbances. Identifying this phenotype could be clinically valuable, as circadian-targeted strategies show promise for reducing depressive symptoms and stabilising illness course. Further investigation of underlying circadian disturbances in mood syndromes is needed to evaluate the clinical utility of this phenotype and guide the optimal use of circadian-targeted interventions.

Social-biological influences on sleep duration among adult residents of Northeastern China

Background

Cold climates traditionally have conferred long sleep duration in the residents in northeast China; however, modern lifestyle reduces sleep duration. In this study, we investigated social-biological factors influencing sleep duration in the adult residents in northeast China.

Methods

This study was performed using data from the Investigation of Chronic Disease Morbidity Rate and Risk Factors of Adults in Jilin Province, China. Associations between sleep duration and indices of demographic characteristics, health-related behaviors, and disease history in adult residents were analyzed using univariate analysis and multivariate logistic regression analysis.

Results

The mean sleep duration was 7.24 h. Of the 21,435 participants, approximately 53.4% had short sleep duration (sleep duration per day < 7 h), and 10.5% had long sleep duration (sleep duration per day > 9 h). There were associations between short sleep duration and indices, including age, place of residence, marital status, educational level, alcohol drinking, dietary, obesity, and history of coronary heart disease (CHD) or myocardial infarction (MI). There existed associations of long sleep duration with indices, such as age, place of residence, occupation, educational level, average monthly earnings, and physical exercise.

Conclusion

Short sleep duration is common among residents in northeast China. Age, place of residence, and educational level are implicated in both short sleep duration and long sleep duration. Short sleep duration inclines to link with the indices (marital status, alcohol drinking, dietary, obesity, and history of CHD or MI). However, long sleep duration is relevant to the indices (occupation, average monthly earnings, and physical exercise).

Metabolic syndrome and actigraphy measures of sleep and circadian rhythms in bipolar disorders during remission

OBJECTIVE

This study explored the correlations between sleep and circadian rhythm measures and the metabolic syndrome (MetS) components in remitted patients with bipolar disorder (BD).

METHOD

Euthymic patients with BD (n = 67) were recorded by 3 weeks with actigraphy. We used nonparametric correlations to study the links between the MetS parameters, atherogenic index of plasma (AIP), sleep efficacy, sleep latency, fragmentation index, and phase and amplitude of rhythms. We performed multivariable analyses to take into account potential confounding factors such as sleep apnea risk, antipsychotics use, and smoker status.

RESULTS

We found correlations between lower sleep efficiency and higher triglyceride levels (P = 0.002), lower M10 onset (beginning of the 10 most active hours during the 24-h cycle) and higher systolic blood pressure (P = 0.03), higher fragmentation index and higher systolic blood pressure (P = 0.009), lower sleep efficiency, higher fragmentation index, and higher AIP (respectively P = 0.02 and P = 0.04). These correlations mostly remained significant when adjusting for confounders, with the exception of M10 onset and systolic blood pressure.

CONCLUSION

Sleep efficiency and fragmentation index might contribute to the cardiovascular risk of patients with BD independently of major confounding factors. Although these associations did not imply causality, proposing interventions on sleep quality and circadian rhythm regularity might contribute to reduce cardiovascular risk in patients with BD.

Which Sleep Health Characteristics Predict All-Cause Mortality in Older Men? An Application of Flexible Multivariable Approaches

Study Objectives

Sleep is multidimensional, with domains including duration, timing, continuity, regularity, rhythmicity, quality, and sleepiness/alertness. Individual sleep characteristics representing these domains are known to predict health outcomes. However, most studies consider sleep characteristics in isolation, resulting in an incomplete understanding of which sleep characteristics are the strongest predictors of health outcomes. We applied three multivariable approaches to robustly determine which sleep characteristics increase mortality risk in the osteoporotic fractures in men sleep study.

Methods

In total, 2,887 men (mean 76.3 years) completed relevant assessments and were followed for up to 11 years. One actigraphy or self-reported sleep characteristic was selected to represent each of seven sleep domains. Multivariable Cox models, survival trees, and random survival forests were applied to determine which sleep characteristics increase mortality risk.

Results

Rhythmicity (actigraphy pseudo-F statistic) and continuity (actigraphy minutes awake after sleep onset) were the most robust sleep predictors across models. In a multivariable Cox model, lower rhythmicity (hazard ratio, HR [95%CI] =1.12 [1.04, 1.22]) and lower continuity (1.16 [1.08, 1.24]) were the strongest sleep predictors. In the random survival forest, rhythmicity and continuity were the most important individual sleep characteristics (ranked as the sixth and eighth most important among 43 possible sleep and non-sleep predictors); moreover, the predictive importance of all sleep information considered simultaneously followed only age, cognition, and cardiovascular disease.

Conclusions

Research within a multidimensional sleep health framework can jumpstart future research on causal pathways linking sleep and health, new interventions that target specific sleep health profiles, and improved sleep screening for adverse health outcomes.

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.

Sleep quality, chronotype and metabolic syndrome components in bipolar disorders during the remission period: Results from the FACE-BD cohort

Data on sleep or circadian abnormalities and metabolic disturbances in euthymic bipolar disorders are scarce and based on small sample sizes. The aim of this study was to explore the associations between sleep disturbances, chronotype and metabolic components in a large sample of euthymic patients with bipolar disorders (BD). From 2009 to 2015, 752 individuals with bipolar disorders from the FACE-BD cohort were included and assessed for sleep quality, chronotype and metabolic components. The Structured Clinical Interview for DSM-IV Axis I Disorders (SCID) was used to confirm the diagnosis of BD. Subjective sleep quality was measured with the Pittsburgh Sleep Quality Index and chronotype with the Composite Scale of Morningness. Sociodemographic and clinical characteristics, psychotropic treatment, psychiatric comorbidities and blood samples were collected. In our sample, 22.4% of individuals with BD presented with a metabolic syndrome, 53.7% had sleep disturbances, 25.4% were considered as having an evening chronotype and 12.6% as having a morning chronotype. Independently of potential confounders, euthymic patients with sleep disturbances had a higher abdominal circumference, and patients with evening chronotype had a significantly higher level of triglycerides. There was an association between evening chronotype and an increased atherogenic index of plasma (OR = 4.8, 95%CI = 1.6-14.7). Our findings contribute the scant literature on the relationship between sleep quality, chronotype and cardiometabolic components in euthymic individuals with BD and highlight the need to improve quality of sleep and patient education about healthier sleep-hygiene practices.

Molecular Mechanisms of Bipolar Disorder: Progress Made and Future Challenges

Bipolar disorder (BD) is a chronic and progressive psychiatric illness characterized by mood oscillations, with episodes of mania and depression. The impact of BD on patients can be devastating, with up to 15% of patients committing suicide. This disorder is associated with psychiatric and medical comorbidities and patients with a high risk of drug abuse, metabolic and endocrine disorders and vascular disease. Current knowledge of the pathophysiology and molecular mechanisms causing BD is still modest. With no clear biological markers available, early diagnosis is a great challenge to clinicians without previous knowledge of the longitudinal progress of illness. Moreover, despite recommendations from evidence-based guidelines, polypharmacy is still common in clinical treatment of BD, reflecting the gap between research and clinical practice. A major challenge in BD is the development of effective drugs with low toxicity for the patients. In this review article, we focus on the progress made and future challenges we face in determining the pathophysiology and molecular pathways involved in BD, such as circadian and metabolic perturbations, mitochondrial and endoplasmic reticulum (ER) dysfunction, autophagy and glutamatergic neurotransmission; which may lead to the development of new drugs.

The association between meal timing and frequency with cardiometabolic profile in patients with bipolar disorder

OBJECTIVE

The goal of this study was to explore the association of timing of and frequency of meals with markers of cardiometabolic risk in patients with bipolar disorder in out-patient maintenance treatment.

METHODS

We used Pittsburgh Sleep Diary and actigraphy measures for individuals with bipolar I disorder. Linear and logistic regression analyses were used to determine whether dinnertime, instability of dinnertime, and/or interval between meals were associated with metabolic syndrome and its components.

RESULTS

Later dinnertime was associated with greater waist circumference (β = 0.25, P = 0.02) after adjusting for age, sex, dinner-to-bed interval, and sleep duration. Longer breakfast-to-lunch intervals were also associated with greater waist circumferences (β =-.35, P = .002) after adjusting for age, sex, and sleep duration. Neither instability of dinnertime nor number of meals per day was associated with the metabolic syndrome or its components.

CONCLUSION

Weight gain is often perceived as inevitable side-effect of medications. While patients often need to be on medication to function, a more careful lifestyle assessment with attention to social rhythms and timing of activities may be critical not only for mood stability, but also to reduce cardiovascular risk.

An Integrated Risk Reduction Intervention can reduce body mass index in individuals being treated for bipolar I disorder: results from a randomized trial

OBJECTIVES

We conducted a randomized, controlled trial comparing the efficacy of an Integrated Risk Reduction Intervention (IRRI) to a control condition with the objective of improving mood stability and psychosocial functioning by reducing cardiometabolic risk factors in overweight/obese patients with bipolar I disorder.

METHODS

A total of 122 patients were recruited from our outpatient services and randomly allocated to IRRI (n = 61) or psychiatric care with medical monitoring (n = 61). Individuals allocated to IRRI received psychiatric treatment and assessment, medical monitoring by a nurse, and a healthy lifestyle program from a lifestyle coach. Those allocated to the control condition received psychiatric treatment and assessment and referral, if indicated, for medical problems. A mixed-effects model was used to examine the impact of the interventions on body mass index (BMI). Exploratory moderator analyses were used to characterize those individuals likely to benefit from each treatment approach.

RESULTS

Analyses were conducted on data for the IRRI (n = 58) and control (n = 56) participants with ≥ 1 study visit. IRRI was associated with a significantly greater rate of decrease in BMI (d = -0.51, 95% confidence interval: -0.91 to -0.14). Three variables (C-reactive protein, total cholesterol, and instability of total sleep time) contributed to a combined moderator of faster decrease in BMI with IRRI treatment.

CONCLUSIONS

Overweight/obese patients with bipolar disorder can make modest improvements in BMI, even when taking medications with known potential for weight gain. Our finding that a combination of three baseline variables provides a profile of patients likely to benefit from IRRI will need to be tested further to evaluate its utility in clinical practice.

Circadian rhythms and sleep in bipolar disorder: implications for pathophysiology and treatment

PURPOSE OF REVIEW

Multiple lines of evidence support the conceptualization of bipolar disorder as a disorder of circadian rhythms. Considering bipolar disorder in the framework of circadian disturbances also helps understand the clinical phenomenology pointing toward a multisystemic involvement.

RECENT FINDINGS

Patients with bipolar disorder show altered rhythmicity in body temperature and melatonin rhythms, high day-to-day variability in activity and sleep timing, persistent disturbances of sleep or wake cycles, including disturbances of sleep continuity. The internal clocks are, indeed, responsible for regulating a variety of physiologic functions, including appetitive behaviors, cognitive functions and metabolism.

SUMMARY

An underlying circadian pathology in bipolar disorder is a unifying explicatory model for the high psychiatric and medical comorbidity observed during the long-term course of the disorder. This model also provides a rationale for therapeutic interventions aimed at re-entraining the internal clock.

Links between sleep and body mass index in bipolar disorders: an exploratory study

STUDY OBJECTIVES

Obesity and excess bodyweight are highly prevalent in individuals with bipolar disorders (BD) and are associated with adverse consequences. Multiple factors may explain increased bodyweight in BD including side effects of psychotropic medications, and reduced physical activity. Research in the general population demonstrates that sleep disturbances may also contribute to metabolic burden. We present a cross-sectional study of the associations between body mass index (BMI) and sleep parameters in patients with BD as compared with healthy controls (HC).

METHODS

Twenty-six French outpatients with remitted BD and 29 HC with a similar BMI completed a 21-day study of sleep parameters using objective (actigraphy) and subjective (PSQI: Pittsburgh Sleep Quality Index) assessments.

RESULTS

In BD cases, but not in HC, higher BMI was significantly correlated with lower sleep efficiency (P=0.009) and with several other sleep parameters: shorter total sleep time (P=0.01), longer sleep onset latency (P=0.05), higher fragmentation index (P=0.008), higher inter-day variability (P=0.05) and higher PSQI total score (P=0.004).

CONCLUSIONS

The findings suggest a link between a high BMI and several sleep disturbances in BD, including lower sleep efficiency. Physiological mechanisms in BD cases may include an exaggeration of phenomena observed in non-clinical populations. However, larger scale studies are required to clarify the links between metabolic and sleep-wake cycle disturbances in BD.

Sleep in remitted bipolar disorder: a naturalistic case-control study using actigraphy

INTRODUCTION

Findings from actigraphic studies suggesting that sleep and circadian rhythms are disrupted in bipolar disorder (BD) patients have been undermined by methodological heterogeneity and the failure to adequately address potential confounders.

METHOD

Twenty-six euthymic BD cases and 29 healthy controls (HC), recruited from University Paris-Est and matched for age and gender, were compared on subjective (Pittsburgh Sleep Questionnaire Inventory; PQSI) and objective (mean scores and variability in actigraphy) measures of sleep as recorded by over 21 consecutive days.

RESULTS

Multivariate generalized linear modelling (GLM) revealed significant differences between BD cases and HC for five PSQI items (total score and four subscales), four actigraphy variables (mean scores) and five actigraphy variability measures. Backward stepwise linear regression (BSLR) indicated that a combination of four variables (mean sleep duration, mean sleep latency, variability of the fragmentation index over 21 days, and mean score on PSQI daytime dysfunction sub-scale) correctly classified 89% of study participants as cases or controls (Chi-square=39.81; df=6; p=0.001).

LIMITATIONS

The sample size (although larger than most actigraphy studies) and incomplete matching of cases and controls may have influenced our findings. It was not possible to control for potential effects of psychotropic medication or differences in employment status between groups.

CONCLUSIONS

When potential confounders of sleep and circadian profiles are adequately taken into account (particularly age, gender, daytime sleepiness, mood symptoms, body mass index, and risk of sleep apnoea), a selected subset of quantitative (mean scores) and qualitative (variability) features differentiated euthymic BD cases from HC.

Recent advances in sleep-wake cycle and biological rhythms in bipolar disorder

The cyclical nature of periodic switches in energy, motor activation and sleep-wake cycles in bipolar disorder suggests a strong underlying relationship with disturbances in chronobiology. Current research is refining our understanding of the various patterns of sleep-wake and biological rhythms alterations at early and later stages of this illness, as well as across its depressive/fatigue, manic/hypomanic and euthymic phases. This research focuses on early detection and subsequent monitoring to predict and better manage recurrent episodes. Sleep-wake cycle and biological rhythms disturbances are also well known to affect other key aspects of physical health (notably metabolic functions), cognitive performance and elevated risks for suicide. Increasing evidence now supports the integration of behavioural or pharmacological therapeutic strategies that target the sleep-wake and circadian systems in the ongoing treatment of various phases of bipolar disorder.

Season of birth is associated with adult body mass index in patients with bipolar disorder

Cardiovascular risk factors, such as abdominal obesity and obesity in general, are very prevalent among patients with bipolar disorder (BD). Although long-term use of psychotropic medications is an important determinant of these risk factors, other evidence suggests that early development may interact with the mood disorder diathesis to exponentially increase the risk of obesity. The goal of our study was to test whether season of birth is associated with adult body mass index (BMI) and abdominal obesity in individuals with bipolar disorder. We compared season of birth effects on BMI in 375 adult patients with bipolar disorder and 196 adult patients with unipolar major depression. We found a significant season of birth effect on BMI in patients with bipolar disorder, but not unipolar. In patients with bipolar disorder, season of birth was also associated with waist circumference, with a stronger effect in males. Season of birth affects adult BMI and waist circumference in patients with bipolar disorder, but not in patients with unipolar depression. Our results suggest that early environmental factors, yet to be identified, interact with specific neurobiological features of bipolar disorder to determine stable traits and disease risk factors in adult life.