Shorter sleep duration and better sleep quality are associated with greater tissue density in the brain

Association Between Sleep Duration and Cardiovascular Disease Among Asian Americans

BACKGROUND

Cardiovascular disease (CVD) prevalence varies widely among Asian American adults. The American Heart Association added healthy sleep to its metrics to define ideal cardiovascular health. Little is known about the association between sleep and CVD prevalence among Asian subgroups. We aim to examine the association between suboptimal sleep duration and CVD risk prevalence among Asian American subgroups.

METHODS AND RESULTS

We used 2012 to 2018 National Health Interview Survey data to examine the association between suboptimal sleep duration and CVD prevalence. We included 6868 self-identifying Asian adults age >40 years (Asian Indian [n=1053], Chinese [n=1415], Filipino [n=1734], and Other Asian [n=2666] adults). Suboptimal sleep was defined as <7 or >9 hours per night. CVD was defined as self-reported stroke, heart attack, coronary artery disease, or angina. Logistic regression was used to calculate odds ratios and 95% CI to estimate the association between suboptimal sleep duration and CVD prevalence. Filipino and Other Asian participants with suboptimal sleep had the highest prevalence of CVD. Aggregated Asian American participants with suboptimal sleep duration had a higher prevalence of CVD (odds ratio [95% CI, 1.35 [1.09-1.68]) compared with those with optimal sleep duration. After stratification by race or ethnicity or both, a significant association persisted for Other Asian participants (1.77 [95% CI, 1.27-2.46]) but not among all other Asian American subgroups.

CONCLUSIONS

Our study highlights the heterogeneity of CVD prevalence associated with suboptimal sleep duration among Asian American adults. Future studies should consider how different measures of sleep duration and quality affect CVD outcomes among disaggregated Asian American subgroups.

Poor self-reported sleep is associated with prolonged white matter T2 relaxation in psychotic disorders

Background

Psychotic disorders are characterized by white matter (WM) abnormalities; however, their relationship with the various aspects of illness presentation remains unclear. Sleep disturbances are common in psychosis, and emerging evidence suggests that sleep plays a critical role in WM physiology. Therefore, it is plausible that sleep disturbances are associated with impaired WM integrity in these disorders. To test this hypothesis, we examined the association of self-reported sleep disturbances with WM transverse (T2) relaxation times in a cross-diagnostic sample of patients with psychosis.

Methods

A total of 28 patients with psychosis (11 schizophrenia spectrum disorders and 17 bipolar disorder with psychotic features) were included. Metabolite (N-acetyl aspartate, choline, and creatine) and water T2 relaxation times were measured in the anterior corona radiata at 4T. Sleep was evaluated using the Pittsburgh Sleep Quality Index (PSQI).

Results

PSQI total score showed a moderate to strong positive correlation with water T2 (r = 0.64, p< 0.001). Linear regressions showed that this association was independent of the overall severity of depressive, manic, or psychotic symptoms. In our exploratory analysis, sleep disturbance was correlated with free water percentage, suggesting that increased extracellular water may be a mechanism underlying the association of disturbed sleep and prolonged water T2 relaxation.

Conclusion

Our results highlight the connection between poor sleep and WM abnormalities in psychotic disorders. Future research using objective sleep measures and neuroimaging techniques suitable to probe free water is needed to further our insight into this relationship.

Reduced Health-Related Quality of Life Due to Mobile Phone Dependence in a Sample of Chinese College Students: The Mediating Role of Chronotype and Sleep Quality

PURPOSE

Presenting a chain mediation model to investigate whether mobile phone dependence results in a reduction in health-related quality of life (HRQoL) among Chinese college students, through the mediating effect of chronotype and sleep quality.

DESIGN AND SETTING

A cross-sectional survey was conducted on students from a Chinese university using a validated structured questionnaire.

SAMPLE

2014 freshmen.

MEASURES

The study measured the students' level of mobile phone dependence using the Self-rating Questionnaire for Adolescent Problematic Mobile Phone Use. Chronotype and sleep quality were measured by the Chinese version of the Morningness-Eveningness Questionnaire (MEQ) and the Pittsburgh Sleep Quality Index (PSQI), respectively. HRQoL was evaluated using the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L), including a descriptive system and a visual analog scale (VAS).

ANALYSIS

Descriptive statistical analysis, correlation analysis, and mediation analysis.

RESULTS

Mobile phone dependence had a significant negative effect on HRQoL as indicated by both the EQ-5D-5L index score and EQ-VAS score (P < .001 for both). Additionally, it was found to significantly predict chronotype (MEQ score) (β = -.546, P < .001) and sleep quality (PSQI score) (β = .163, P < .001). Chronotype negatively predict sleep quality (β = -.058, P < .001), and sleep quality was a significant negative predictor of HRQoL (EQ-5D-5L index score, β = -.008, P < .001; EQ-VAS score, β = -1.576, P < .001).

CONCLUSION

Mobile phone dependence negatively impacts students' HRQoL through chronotype and sleep quality, and there is a chain mediating effect. Students should consider making lifestyle changes to improve their HRQoL and promote health.

Poor Self-Reported Sleep is Associated with Prolonged White Matter T2 Relaxation in Psychotic Disorders

Background

Schizophrenia (SZ) and bipolar disorder (BD) are characterized by white matter (WM) abnormalities, however, their relationship with illness presentation is not clear. Sleep disturbances are common in both disorders, and recent evidence suggests that sleep plays a critical role in WM physiology. Therefore, it is plausible that sleep disturbances are associated with impaired WM integrity in these disorders. To test this hypothesis, we examined the association of self-reported sleep disturbances with WM transverse (T2) relaxation times in patients with SZ spectrum disorders and BD with psychotic features.

Methods

28 patients with psychosis (17 BD-I, with psychotic features and 11 SZ spectrum disorders) were included. Metabolite and water T2 relaxation times were measured in the anterior corona radiata at 4T. Sleep was evaluated using the Pittsburgh Sleep Quality Index.

Results

PSQI total score showed a moderate to strong positive correlation with water T2 (r = 0.64, p<0.001). Linear regressions showed that this association was specific to sleep disturbance but was not a byproduct of exacerbation in depressive, manic, or psychotic symptoms. In our exploratory analysis, sleep disturbance was correlated with free water percentage, suggesting that increased extracellular water may be a mechanism underlying the association of disturbed sleep and prolonged water T2 relaxation.

Conclusion

Our results highlight the connection between poor sleep and WM abnormalities in psychotic disorders. Future research using objective sleep measures and neuroimaging techniques suitable to probe free water is needed to further our insight into this relationship.

Chronotype and subjective sleep quality predict white matter integrity in young people with emerging mental disorders

Protecting brain health is a goal of early intervention. We explored whether sleep quality or chronotype could predict white matter (WM) integrity in emerging mental disorders. Young people (N = 364) accessing early-intervention clinics underwent assessments for chronotype, subjective sleep quality, and diffusion tensor imaging. Using machine learning, we examined whether chronotype or sleep quality (alongside diagnostic and demographic factors) could predict four measures of WM integrity: fractional anisotropy (FA), and radial, axial, and mean diffusivities (RD, AD and MD). We prioritised tracts that showed a univariate association with sleep quality or chronotype and considered predictors identified by ≥80% of machine learning (ML) models as 'important'. The most important predictors of WM integrity were demographics (age, sex and education) and diagnosis (depressive and bipolar disorders). Subjective sleep quality only predicted FA in the perihippocampal cingulum tract, whereas chronotype had limited predictive importance for WM integrity. To further examine links with mood disorders, we conducted a subgroup analysis. In youth with depressive and bipolar disorders, chronotype emerged as an important (often top-ranking) feature, predicting FA in the cingulum (cingulate gyrus), AD in the anterior corona radiata and genu of the corpus callosum, and RD in the corona radiata, anterior corona radiata, and genu of corpus callosum. Subjective quality was not important in this subgroup analysis. In summary, chronotype predicted altered WM integrity in the corona radiata and corpus callosum, whereas subjective sleep quality had a less significant role, suggesting that circadian factors may play a more prominent role in WM integrity in emerging mood disorders.

Everyday Discrimination and Sleep Among Migrant and Non-migrant Filipinos: Longitudinal Analyses from the Health of Philippine Emigrants Study (HoPES)

This study aimed to (1) identify differences in sleep patterns between Filipino migrants and non-migrants across 2 years and (2) explore the impact of discrimination trajectories on sleep trajectories. The Health of Philippine Emigrants Study (HoPES) consisted of a migrant (n = 832) and non-migrant cohort (n = 805), with baseline data collected in the Philippines. Both cohorts were followed longitudinally, with the non-migrants followed in the Philippines and the migrant cohort followed to the United States. Sleep duration, quality, and difficulty were assessed with the National Institutes of Health Patient-Reported Outcomes Information System (PROMIS) inventory, and discrimination was measured with an adapted version of the Everyday Discrimination scale. Migrants reported a faster decline in sleep duration (- 12 min a year) but higher sleep quality than non-migrants over 2 years. Migrants who reported high initial levels of everyday discrimination also reported faster declines in sleep duration and a slower decline in sleep difficulty. Further, migrants who reported stable (versus declining) levels of discrimination over 2 years reported a faster decline in sleep quality. These results speak to the complexity of immigrant health patterns and long-term associations between discrimination and sleep processes.

Development of morning-eveningness in adolescence: implications for brain development and psychopathology

BACKGROUND

Morning-evening preference is defined as an individual's preference for a morning- or evening-oriented rhythm. Across adolescence, a preference for eveningness becomes more predominant. Although eveningness is cross-sectionally associated with internalizing and externalizing psychopathology, few studies have examined developmental changes in eveningness and its potential biological substrates. Here, we investigated the longitudinal relationships among the trajectory of eveningness preference, internalizing and externalizing psychopathology and white matter development, across adolescence.

METHODS

Two-hundred and nine adolescents (49% male) were assessed longitudinally at four separate time points between 12 and 19 years of age. Morning-evening preference and internalizing and externalizing symptoms were assessed at each time point. Diffusion-weighted images were acquired on a subset of participants at the final two time points to estimate changes in global mean fractional anisotropy (FA). Linear mixed models were performed to estimate the change in eveningness over time. A series of linear regression models assessed the influence of change in eveningness on psychopathology and white matter development at age 19.

RESULTS

Across the sample, a preference for eveningness became more predominant by 19 years of age. Greater individual-level change towards eveningness significantly predicted greater severity in externalizing, but not internalizing, symptoms at 19 years of age. In contrast, change in psychopathology from 12 to 19 years of age was not associated with morning-eveningness at age 19. A change towards eveningness predicted an attenuated increase in FA between 17 and 19 years of age.

CONCLUSIONS

This study suggests that developmental changes in morning-evening preference may predict both neurodevelopmental and psychological outcomes in adolescents.

The Effect of Learning Burnout on Sleep Quality in Primary School Students: The Mediating Role of Mental Health

Due to the growth of research on sleep, mental health, and learning burnout on healthy growth and its related public health significance of adolescents, this study aimed to provide a deeper understanding of the effect of mental health and learning burnout on sleep among primary school students. The sleep quality (subjective sleep quality, sleep time, sleep latency, sleep duration, sleep efficiency, sleep disturbance, and daytime dysfunction), mental health, and learning burnout (exhaustion, learning cynicism, and reduced efficacy) of 900 students of grades 3–6 in primary schools were assessed in 2020. The PSQI scores of participants were 4.19 ± 2.545, of which a number of 322 (39.03%) students had sleep disturbance (PSQI scores ≧ 5). Binary logistic regression analysis showed that screen time (OR = 1.518, 95% CI: 1.164–1.980), ranking status (OR = 0.659, 95% CI: 0.480–0.907), learning burnout (OR = 1.088, 95% CI: 1.067–1.108), and mental health (OR = 4.672, 95% CI: 1.954–11.173) were the influencing factors for sleep quality of grade 3–6 students. According to the mediation effect analyses, mental health played a mediating effect (58.73% of the total effect) on the relationship between learning burnout and sleep quality. In conclusion, primary school students in Hunan of China have prominent sleep problems, and the daytime dysfunction caused by sleep problems is the most serious. Learning burnout positively predicted poorer sleep quality, and mental health played a mediating effect on the relationship between learning burnout and sleep quality.

Evaluating the role of rare genetic variation in sleep duration

OBJECTIVES

To explore the roles of rare and high-impact variants in sleep duration.

DESIGN

Based on the recently released UK Biobank 200k exome dataset, an exome-wide association study was conducted to detect rare variants (minor allele frequency <0.01) contributing to sleep duration. Variant annotations were performed by the software tool ANNOVAR. Gene-based burden tests of sleep duration were conducted by the SKAT R-package. After quality control, 137,047 subjects were included in this study. CAUSALdb database was used to explore the related mental traits of identified genes.

RESULTS

We detected 730,572 variants with MAF < 1%, including 3873 frameshift variants, 3977 nonframeshift variants, 449,632 nonsynonymous variants, 1293 startloss variants, 10,254 stopgain variants, 413 stoploss variants, 261,130 synonymous variants, and 3102 variants are annotated as unknown. The burden test of exonic variants detected two exome-wide significant associations for sleep duration including TMIE at 3p21.31 (P_{Bonferroni adjusted} = 0.015) and ZIC2 at 13q32.3 (P_{Bonferroni adjusted} = 0.047). There are only nonsynonymous contained in TMIE; as for ZIC2, we detected 2 annotations of variants: nonsynonymous (P_{Bonferroni adjusted} =2.04 × 10^-4) and nonframeshift (P_{Bonferroni adjusted} =0.85). TMIE and ZIC2 were reported to be associated with several mental traits, such as chronotype, depression, and brain natriuretic peptide in published study.

CONCLUSION

This study reported 2 novel candidate genes for a sleep duration, supporting the roles of rare genetic variants in the regulation of sleep duration.

ENIGMA-Sleep: Challenges, opportunities, and the road map

Neuroimaging and genetics studies have advanced our understanding of the neurobiology of sleep and its disorders. However, individual studies usually have limitations to identifying consistent and reproducible effects, including modest sample sizes, heterogeneous clinical characteristics and varied methodologies. These issues call for a large-scale multi-centre effort in sleep research, in order to increase the number of samples, and harmonize the methods of data collection, preprocessing and analysis using pre-registered well-established protocols. The Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) consortium provides a powerful collaborative framework for combining datasets across individual sites. Recently, we have launched the ENIGMA-Sleep working group with the collaboration of several institutes from 15 countries to perform large-scale worldwide neuroimaging and genetics studies for better understanding the neurobiology of impaired sleep quality in population-based healthy individuals, the neural consequences of sleep deprivation, pathophysiology of sleep disorders, as well as neural correlates of sleep disturbances across various neuropsychiatric disorders. In this introductory review, we describe the details of our currently available datasets and our ongoing projects in the ENIGMA-Sleep group, and discuss both the potential challenges and opportunities of a collaborative initiative in sleep medicine.

Self-reported sleep relates to microstructural hippocampal decline in ß-amyloid positive Adults beyond genetic risk

STUDY OBJECTIVES

A critical role linking sleep with memory decay and β-amyloid (Aβ) accumulation, two markers of Alzheimer's disease (AD) pathology, may be played by hippocampal integrity. We tested the hypotheses that worse self-reported sleep relates to decline in memory and intra-hippocampal microstructure, including in the presence of Aβ.

METHODS

Two-hundred and forty-three cognitively healthy participants, aged 19-81 years, completed the Pittsburgh Sleep Quality Index once, and two diffusion tensor imaging sessions, on average 3 years apart, allowing measures of decline in intra-hippocampal microstructure as indexed by increased mean diffusivity. We measured memory decay at each imaging session using verbal delayed recall. One session of positron emission tomography, in 108 participants above 44 years of age, yielded 23 Aβ positive. Genotyping enabled control for APOE ε4 status, and polygenic scores for sleep and AD, respectively.

RESULTS

Worse global sleep quality and sleep efficiency related to more rapid reduction of hippocampal microstructure over time. Focusing on efficiency (the percentage of time in bed at night spent asleep), the relation was stronger in presence of Aβ accumulation, and hippocampal integrity decline mediated the relation with memory decay. The results were not explained by genetic risk for sleep efficiency or AD.

CONCLUSIONS

Worse sleep efficiency related to decline in hippocampal microstructure, especially in the presence of Aβ accumulation, and Aβ might link poor sleep and memory decay. As genetic risk did not account for the associations, poor sleep efficiency might constitute a risk marker for AD, although the driving causal mechanisms remain unknown.

The association between sleep quality, preoperative risk factors for chronic postoperative pain and postoperative pain intensity 12 months after knee and hip arthroplasty

BACKGROUND

Chronic postoperative pain following total joint replacement (TJA) is a substantial clinical problem, and poor sleep may affect predictive factors for postoperative pain, such as pain catastrophizing. However, the magnitude of these associations is currently unknown. This exploratory study investigated (1) the relationship between preoperative sleep quality, clinical pain intensity, pain catastrophizing, anxiety, and depression and (2) their associations with chronic postoperative pain following TJA.

METHODS

This secondary analysis from a larger randomized controlled trial included rest pain intensity (preoperative and 12 months postoperative; visual analogue scale, VAS), preoperative Pittsburgh Sleep Quality Index (PSQI), Pain Catastrophizing Scale (PCS), Hospital Anxiety and Depression Scale (HADS) data from 74 knee and 89 hip osteoarthritis (OA) patients scheduled for TJA. Poor sleepers were identified based on preoperative PSQI scores higher than 5.

RESULTS

Poor sleepers demonstrated higher preoperative VAS, pain catastrophizing, anxiety, and depression compared with good sleepers (all p < 0.003). Preoperative PSQI (β = 0.23, p = 0.006), PCS (β = 0.44, p < 0.005), and anxiety (β = 0.18, p = 0.036) were independent factors for preoperative VAS. Preoperative VAS (β = 0.32, p < 0.005), but not preoperative sleep quality (β = -0.06, p = 0.5), was an independent factor for postoperative VAS.

CONCLUSION

The OA patients reporting poor preoperative sleep quality show higher preoperative pain, pain catastrophizing, anxiety, and depression. High preoperative pain intensity, but not poor sleep quality, was associated with higher chronic postoperative pain intensity. Future studies are encouraged to explore associations between sleep and chronic postoperative pain.

Association between Regular Exercise and Self-Rated Health and Sleep Quality among Adults in Japan during the COVID-19 Pandemic

Regular exercise may be associated with better self-rated health and sleep status. However, this correlation among various age groups, such as young, middle-aged, and older people, as well as during the COVID-19 pandemic, has not been examined. This study examined the correlation between regular exercise and self-rated health and sleep quality among adults in Japan during the COVID-19 pandemic. Data were collected using an online survey conducted between February 26 and 27, 2021. A total of 1410 adults in Japan (age range, 20–86 years) completed the online survey. Regular exercise was divided into: (1) more than 30 min of moderate exercise a day, (2) more than 2 days per week, and (3) continuous for 1 year or longer. Self-rated health and sleep quality were assessed using the Likert scale. After adjusting for multiple confounders, regular exercise was correlated with decreased poor self-rated health and poor sleep quality in middle-aged adults; however, no significant correlation was observed among young and older adults. The promotion of regular exercise among middle-aged people during the COVID-19 pandemic may contribute to better self-rated health and sleep quality status.

Trastornos del sueño en emergencias y desastres

Los trastornos del sueño son frecuentes en la población y una causa importante de morbilidad. El objetivo de esta revisión es evaluar las alteraciones del sueño en periodos de emergencia y desastres. A lo largo de la historia, la esfera biopsicosocial y el sueño de las personas ha sido abrumada por múltiples eventos a gran escala, tales como desastres naturales, tragedias provocadas por el hombre, conflictos bélicos, crisis sociales y pandemias, cuya experiencia puede derivar en problemas de salud a corto, mediano y/o largo plazo. En los estudios analizados, se ha observado el impacto negativo de las emergencias y desastres en el sueño, por lo que ha cobrado gran relevancia la difusión y promoción de medidas que incentiven el buen dormir. Debido a la llegada del COVID-19 y a la situación de confinamiento por periodos prolongados en el hogar para prevenir su propagación, han surgido importantes consecuencias a nivel social. Ciertos factores ocupacionales y características de los desastres se asocian a mayor comorbilidad, un alto riesgo de experimentar agotamiento físico, trastornos psicológicos e insomnio en grupos altamente vulnerables, como lo son los profesionales de la salud, rescatistas y socorristas. El insomnio es el trastorno de sueño más frecuente en la población general y su empeoramiento en el contexto de pandemia por COVID-19 representa un nuevo problema en salud pública. Es por ello, que es indispensable promover campañas de prevención de salud física y mental orientados a la pesquisa precoz y manejo de patologías de la esfera psicosocial, dentro de las posibilidades socioeconómicas.

Association Between Sleep Duration and Intelligence Quotient in 6-Year-Old Children

BACKGROUND

Sufficient sleep during childhood is important for cognitive functions such as learning and successful school performance. This study aimed to investigate the effects of sleep duration on the intelligence quotient (IQ) of 6-year-old children and aimed to analyze whether these effects differed by sex.

METHODS

The IQ of 538 6-year-old Korean participants from the cohort study, "The Environment and Development of Children," was measured during follow-up using the Korean Educational Developmental Institute's Wechsler Intelligence Scale for Children. The total, verbal, and performance IQ scores were evaluated. The relationship between sleep duration and IQ scores after adjusting for maternal age, maternal educational level, maternal occupation, maternal IQ, exposure to secondhand smoking, gestational age, and monthly age and birth season was also assessed.

RESULTS

Longer sleep duration was significantly associated with improved verbal IQ measures (β 0.55; p value 0.030). After stratifying participants by sex, a significant association was observed between sleep duration and total, verbal, and performance IQ scores in boys (total IQ 2.49, p value 0.012; verbal IQ 0.75, p value: 0.037; performance IQ 0.73, p value 0.048), but not in girls.

CONCLUSIONS

The results indicated that only boys show a significant association between IQ scores and sleep duration. These findings support the hypothesis that sleep duration is associated with IQ, in a sex dependent manner. Future studies are needed for a thorough evaluation of the connection between sleep duration and health outcome in young children.

Sex-specific association of poor sleep quality with gray matter volume

STUDY OBJECTIVES

Previous studies were inconsistent with regard to the association of sleep dysfunction on the brain's gray matter volume (GMV). The current study set out to investigate if there is a moderating effect of sex on the relationship between sleep quality in healthy individuals and GMV.

METHODS

We applied voxel-based morphometry in 1,074 young adults of the "Human Connectome Project." An analysis of variance with the factors "sleep quality" (good/poor according to the Pittsburgh Sleep Quality Index, cutoff >5) and "sex" (male, female) on GMV was conducted. Additionally, linear relationships between sleep quality and GMV were tested.

RESULTS

The analysis of variance yielded no main effect for sleep quality, but an interaction between sex and sleep quality for the right superior frontal gyrus. Post hoc t-tests showed that female good sleepers in comparison to female poor sleepers had larger GMV in the right parahippocampal gyrus extending to the right hippocampus (whole-brain family-wise error [FWE]-corrected), as well as smaller GMV in the right inferior parietal lobule (whole-brain FWE-corrected) and the right inferior temporal gyrus (whole brain FWE-corrected). There were no significant effects when comparing male good sleepers to male poor sleepers. Linear regression analyses corroborated smaller GMV in the right parahippocampal gyrus in women with poor sleep quality.

CONCLUSIONS

Poor sleep quality was associated with altered GMV in females, but not in males. Future studies are needed to investigate the neurobiological mechanisms that underlie the sex differences in the association of sleep quality and brain differences found in this study.

Evidence of Genetic Overlap Between Circadian Preference and Brain White Matter Microstructure

Several neuroimaging studies have reported associations between brain white matter microstructure and chronotype. However, it is unclear whether those phenotypic relationships are causal or underlined by genetic factors. In the present study, we use genetic data to examine the genetic overlap and infer causal relationships between chronotype and diffusion tensor imaging (DTI) measures. We identify 29 significant pairwise genetic correlations, of which 13 also show evidence for a causal association. Genetic correlations were identified between chronotype and brain-wide mean, axial and radial diffusivities. When exploring individual tracts, 10 genetic correlations were observed with mean diffusivity, 10 with axial diffusivity, 4 with radial diffusivity and 2 with mode of anisotropy. We found evidence for a possible causal association of eveningness with white matter microstructure measures in individual tracts including the posterior limb and the retrolenticular part of the internal capsule; the genu and splenium of the corpus callosum and the posterior, superior and anterior regions of the corona radiata. Our findings contribute to the understanding of how genes influence circadian preference and brain white matter and provide a new avenue for investigating the role of chronotype in health and disease.

White Matter Microstructure Underlies the Effects of Sleep Quality and Life Stress on Depression Symptomatology in Older Adults

Sleep complaints are the most prevalent syndromes in older adults, particularly in women. Moreover, they are frequently accompanied with a high level of depression and stress. Although several diffusion tensor imaging (DTI) studies reported associations between sleep quality and brain white matter (WM) microstructure, it is still unclear whether gender impacts the effect of sleep quality on structural alterations, and whether these alterations mediate the effects of sleep quality on emotional regulation. We included 389 older participants (176 females, age = 65.5 ± 5.5 years) from the 1000BRAINS project. Neuropsychological examinations covered the assessments of sleep quality, depressive symptomatology, current stress level, visual working memory, and selective attention ability. Based on the DTI dataset, the diffusion parameter maps, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD), were calculated and normalized to a population-specific FA template. According to the global Pittsburgh Sleep Quality Index (PSQI), 119 poor sleepers (PSQI: 10∼17) and 120 good sleepers (PSQI: 3∼6) were identified. We conducted a two by two (good sleepers/poor sleepers) × (males/females) analysis of variance by using tract-based spatial statistics (TBSS) and JHU-ICBM WM atlas-based comparisons. Moreover, we performed a voxel-wise correlation analysis of brain WM microstructure with the neuropsychological tests. Finally, we applied a mediation analysis to explore if the brain WM microstructure mediates the relationship between sleep quality and emotional regulation. No significant differences in brain WM microstructure were detected on the main effect of sleep quality. However, the MD, AD, and RD of pontine crossing tract and bilateral inferior cerebellar peduncle were significant lower in the males than females. Voxel-wise correlation analysis revealed that FA and RD values in the corpus callosum were positively related with depressive symptomatology and negatively related with current stress levels. Additionally, we found a significantly positive association between higher FA values in visual-related WM tracts and better outcomes in a visual pattern recognition test. Furthermore, a mediation analysis suggested that diffusion metrics within the corpus callosum partially mediated the associations between poor sleep quality/high stress and depressive symptomatology.

Effects of Continuous Intake of Rosemary Extracts on Mental Health in Working Generation Healthy Japanese Men: Post-Hoc Testing of a Randomized Controlled Trial

We previously performed a 4 week interventional trial that suggested that continuous intake of rosemary extract improves the mood states, fatigue, and cognitive function of working generation healthy adult Japanese men. However, the severity of depression in participants in our previous study was relatively mild. Therefore, in the present study, a post-hoc analysis of our previous study was conducted, limited to participants whose total mood disturbance (TMD) scores, which indicate greater mood disturbance, were above the median at baseline, to evaluate whether rosemary extract was effective for individuals with poor mental health. Following the intervention, the scores of TMD and “Confusion-Bewilderment” were significantly decreased (both p < 0.05), and scores of “Vigor-Activity” were significantly increased in the rosemary group (n = 8) compared with those in the control group (n = 13; p < 0.01). When comparing the scores from pre- and post-intervention, significant improvements in “Tension-Anxiety”, “Vigor-Activity”, “Fatigue on awakening”, “Daytime sleepiness”, and “Psychomotor speed” were observed in the rosemary group only (all p < 0.05). Based on these results, it was expected that rosemary extracts were effective for improving the mental energy and sleep quality of work-age men with poor mental health.

The Role of Sleep Quality, Trait Anxiety and Hypothalamic-Pituitary-Adrenal Axis Measures in Cognitive Abilities of Healthy Individuals

Sleep plays a crucial role in cognitive processes. Sleep and wake memory consolidation seem to be regulated by glucocorticoids, pointing out the potential role of the hypothalamic-pituitary-adrenal (HPA) axis in the relationship between sleep quality and cognitive abilities. Trait anxiety is another factor that is likely to moderate the relationship between sleep and cognition, because poorer sleep quality and subtle HPA axis abnormalities have been reported in people with high trait anxiety. The current study aimed to explore whether HPA axis activity or trait anxiety moderate the relationship between sleep quality and cognitive abilities in healthy individuals. We studied 203 healthy individuals. We measured verbal and visual memory, working memory, processing speed, attention and executive function. Sleep quality was assessed with the Pittsburgh Sleep Quality Index. Trait anxiety was assessed with the State-Trait Anxiety Inventory. HPA axis measures included the cortisol awakening response (CAR), diurnal cortisol slope and cortisol levels during the day. Multiple linear regression analyses explored the relationship between sleep quality and cognition and tested potential moderating effects by HPA axis measures and trait anxiety. Poor sleep quality was associated with poorer performance in memory, processing speed and executive function tasks. In people with poorer sleep quality, a blunted CAR was associated with poorer verbal and visual memory and executive functions, and higher cortisol levels during the day were associated with poorer processing speed. Trait anxiety was a moderator of visual memory and executive functioning. These results suggest that subtle abnormalities in the HPA axis and higher trait anxiety contribute to the relationship between lower sleep quality and poorer cognitive functioning in healthy individuals.

Sleep duration is associated with white matter microstructure and cognitive performance in healthy adults

Reduced sleep duration and sleep deprivation have been associated with cognitive impairment as well as decreased white matter integrity as reported by experimental studies. However, it is largely unknown whether differences in sleep duration and sleep quality might affect microstructural white matter and cognition. Therefore, the present study aims to examine the cross-sectional relationship between sleep duration, sleep quality, and cognitive performance in a naturalistic study design, by focusing on the association with white matter integrity in a large sample of healthy, young adults. To address this, 1,065 participants, taken from the publicly available sample of the Human Connectome Project, underwent diffusion tensor imaging. Moreover, broad cognitive performance measures (NIH Cognition Toolbox) and sleep duration and quality (Pittsburgh Sleep Quality Index) were assessed. The results revealed a significant positive association between sleep duration and overall cognitive performance. Shorter sleep duration significantly correlated with fractional anisotropy (FA) reductions in the left superior longitudinal fasciculus (SLF). In turn, FA in this tract was related to measures of cognitive performance and was shown to significantly mediate the association of sleep duration and cognition. For cognition only, associations shift to a negative association of sleep duration and cognition for participants sleeping more than 8 hr a day. Investigations into subjective sleep quality showed no such associations. The present study showed that real-world differences in sleep duration, but not subjective sleep quality are related to cognitive performance measures and white matter integrity in the SLF in healthy, young adults.

Associations of adolescents' lifestyle habits with their daytime functioning in Japan

OBJECTIVE

To assess associations of adolescents' lifestyle habits with their daytime functioning in Japan.

METHODS

A total of 2,722 questionnaires obtained from pupils in grades 5 to 12 in Japan were assessed by the multiple comparison test to determine significant differences in the lifestyle habits among the self-reported academic performance categories (AP1: very good; AP2: good; AP3: not good; AP4: poor).

RESULTS

The average non-school-day screen time of AP4 pupils was significantly longer than that of AP1 pupils in elementary and junior high schools. In junior and senior high schools, AP4 pupils showed more sleepiness and higher occurrence of breakfast skipping than AP2 pupils. In all school types, sleep duration showed no significant differences among the self-reported academic performance categories.

DISCUSSION

Avoiding sleepiness, breakfast skipping, and heavy media usage is expected to ensure adolescents' daytime functioning. Although not studied here, napping might improve adolescents' daytime functioning.

Association between children's sleep patterns and problematic behaviors at age 5

BACKGROUND

Night-shift lifestyles affect children as well as adults, and are associated with sleep and behavioral problems among children. This study aimed to investigate associations among sleep patterns, individual/environmental factors, and problematic behaviors in children at age 5 years.

METHODS

Data for sleep patterns, individual / environmental factors, and problematic behaviors for 8,689 5-year-old children were collected from health-checkup records. Problematic behaviors investigated were anxious behavior (being afraid, difficulty being separated from the mother), developmental behavior (violence, restlessness, rebellious behavior, restrictive diet, stereotypic play), personal habits (thumb-sucking, nail-biting, tic, masturbation), and excretory problems. The relationships between sleep patterns (bedtime, sleep duration) and the presence of these behaviors were analyzed. Individual / environmental factors that affected problematic behaviors were statistically identified using a tree-form model.

RESULTS

Late bedtime and short sleep duration showed significant adverse effects on children's problematic behaviors - odds ratio (OR): 1.07, 95% confidence interval (CI): 1.03-1.11 and OR: 0.92, 95% CI: 0.87-0.97, respectively. Long television watching time, abnormality at birth, and lack of father's support also showed significant adverse effects on problematic behaviors (OR: 2.34, 95% CI: 1.87-2.94), and significantly affected late bedtime and short sleep duration.

CONCLUSIONS

There were significant associations among sleep patterns, individual / environmental factors, and problematic behaviors in 5-year-old children. Improving children's sleep patterns, reducing the duration of television watching, and improving support from fathers may reduce problematic behaviors.

Gray matter volume and estimated brain age gap are not linked with sleep-disordered breathing

Alzheimer's disease (AD) and sleep-disordered breathing (SDB) are prevalent conditions with a rising burden. It is suggested that SDB may contribute to cognitive decline and advanced aging. Here, we assessed the link between self-reported SDB and gray matter volume in patients with AD, mild cognitive impairment (MCI) and healthy controls (HCs). We further investigated whether SDB was associated with advanced brain aging. We included a total of 330 participants, divided based on self-reported history of SDB, and matched across diagnoses for age, sex and presence of the Apolipoprotein E4 allele, from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Gray-matter volume was measured using voxel-wise morphometry and group differences in terms of SDB, cognitive status, and their interaction were assessed. Further, using an age-prediction model fitted on gray-matter data of external datasets, we predicted study participants' age from their structural images. Cognitive decline and advanced age were associated with lower gray matter volume in various regions, particularly in the bilateral temporal lobes. Brains age was well predicted from the morphological data in HCs and, as expected, elevated in MCI and particularly in AD subjects. However, there was neither a significant difference between regional gray matter volume in any diagnostic group related to the SDB status, nor in SDB-by-cognitive status interaction. Moreover, we found no difference in estimated chronological age gap related to SDB, or by-cognitive status interaction. Contrary to our hypothesis, we were not able to find a general or a diagnostic-dependent association of SDB with either gray-matter volumetric or brain aging.

The associations of BMI with mean diffusivity of basal ganglia among young adults with mild obesity and without obesity

Obesity causes a wide range of systemic diseases and is associated with mood and anxiety disorders. It is also associated with dopaminergic reward system function. However, the relationships between microstructural properties of the dopaminergic system and body mass index (BMI) have not been investigated. In this study, we investigated the associations of BMI with mean diffusivity (MD), diffusion tensor imaging measure in areas of the dopaminergic system (MDDS) in 435 healthy young adults with mild obesity and without obesity (BMI < 40). We detected the association between greater BMI and lower MD of the right globus pallidus and the right putamen. These results suggest that the property of the dopaminergic system is associated with BMI among young adults with mild obesity and without obesity.

Succeeding in deactivating: associations of hair zinc levels with functional and structural neural mechanisms

Zinc is a biologically essential element and involved in a wide range of cellular processes. Here, we investigated the associations of zinc levels in hair with brain activity during the n-back working memory task using functional magnetic resonance imaging, fractional anisotropy (FA) of diffusion tensor imaging, and cognitive differences in a study cohort of 924 healthy young adults. Our findings showed that greater hair zinc levels were associated with lower brain activity during working memory in extensive areas in the default mode network (i.e., greater task-induced deactivation) as well as greater FA in white matter areas near the hippocampus and posterior limbs of the internal capsule. These findings advance previous non-neuroimaging findings of zinc's associations with excitability, excitability-associated disorders, and myelination.

Sleep-wake regulation and the hallmarks of the pathogenesis of Alzheimer's disease

While efficient treatments for Alzheimer's disease (AD) remain elusive, a growing body of research has highlighted sleep-wake regulation as a potential modifiable factor to delay disease progression. Evidence accumulated in recent years is pointing toward a tight link between sleep-wake disruption and the three main hallmarks of the pathogenesis of AD, i.e. abnormal amyloid-beta (Aβ) and tau proteins accumulation, and neurodegeneration. However, all three hallmarks are rarely considered together in the same study. In this review, we gather and discuss findings in favor of an association between sleep-wake disruption and each AD hallmark in animal models and in humans, with a focus on the preclinical stages of the disease. We emphasize that these relationships are likely bidirectional for each of these hallmarks. Altogether, current findings provide strong support for considering sleep-wake disruption as a true risk factor in the early unfolding of AD, but more research integrating recent technical advances is needed, particularly with respect to tau protein and neurodegeneration. Interventional longitudinal studies among cognitively healthy older individuals should assess the practical use of improving sleep-wake regulation to slow down the progression of AD pathogenesis.

The interrelation of sleep and mental and physical health is anchored in grey-matter neuroanatomy and under genetic control

Humans need about seven to nine hours of sleep per night. Sleep habits are heritable, associated with brain function and structure, and intrinsically related to well-being, mental, and physical health. However, the biological basis of the interplay of sleep and health is incompletely understood. Here we show, by combining neuroimaging and behavioral genetic approaches in two independent large-scale datasets (HCP (n = 1106), age range: 22-37, eNKI (n = 783), age range: 12-85), that sleep, mental, and physical health have a shared neurobiological basis in grey matter anatomy; and that these relationships are driven by shared genetic factors. Though local associations between sleep and cortical thickness were inconsistent across samples, we identified two robust latent components, highlighting the multivariate interdigitation of sleep, intelligence, BMI, depression, and macroscale cortical structure. Our observations provide a system-level perspective on the interrelation of sleep, mental, and physical conditions, anchored in grey-matter neuroanatomy.

Empathizing associates with mean diffusivity

Empathizing is defined as “the drive to identify another’s mental states and to respond to these with an appropriate emotion” and systemizing is defined as “the drive to the drive to analyze and construct rule-based systems”. While mean diffusivity (MD) has been robustly associated with several cognitive traits and disorders related with empathizing and systemizing, its direct correlation with empathizing and systemizing remains to be investigated. We undertook voxel-by-voxel investigations of regional MD to discover microstructural correlates of empathizing, systemizing, and the discrepancy between them (D score: systemizing − empathizing). Whole-brain analyses of covariance revealed that across both sexes, empathizing was positively correlated with MD of (a) an anatomical cluster that primarily spreads in the areas in and adjacent to the left dorsolateral prefrontal cortex, left anterior to the middle cingulate cortex, and left insula and (b) an anatomical cluster of the left postcentral gyrus and left rolandic operculum. The former overlaps with positive MD correlates of cooperativeness. The D score and systemizing did not show significant correlations. In conclusion, while increased MD has generally been associated with reduced neural tissues and possibly area function, higher empathizing and cooperativeness were commonly reflected by greater MD values in areas (a) that mainly overlap with areas that play a key role in emotional salience and empathy. In addition, higher empathizing was correlated with greater MD values in areas (b) that play a key role in the mirror neuron system.

Actigraphy-based sleep characteristics and aortic stiffness: the Multi-Ethnic Study of Atherosclerosis

The study aimed to examine the association between objective estimates of sleep duration and quality and aortic stiffness while accounting for the potential confounding effect of sleep-disordered breathing. Participants were part of the Multi-Ethnic Study of Atherosclerosis Sleep study. Sleep duration and quality were assessed by 7-day wrist actigraphy, sleep-disordered breathing by home polysomnography, and aortic stiffness by magnetic resonance imaging-based aortic pulse wave velocity (aPWV), ascending and descending aorta distensibility. Aortic stiffness of participants with "normal" sleep duration (6-8 hours) were compared with those of "short" (<6 hours) and "long" sleep duration (>8 hours) adjusting for common cardiovascular risk factors and apnea-hypopnea index. The sample consisted of 908 participants (mean age 68.4 ± 9.1 years, 55.3% female). There was a significant linear trend of increased aPWV across short (n = 252), normal (n = 552), and long sleep durations (n = 104) (P for trend = .008). Multivariable analysis showed that people with short sleep duration had 0.94 m/s lower aPWV (95% CI: -1.54, -0.35), compared with those with normal sleep duration. In this ethnically diverse community cohort, habitual short sleep duration as estimated by actigraphy was associated with lower aortic stiffness.