Sex differences in sleep: impact of biological sex and sex steroids

The Impact of Sleep on Haematological Parameters in Firefighters

Sleep is a vital process that impacts biological functions such as cell renewal, bone regeneration, and immune system support. Disrupted sleep can interrupt erythropoiesis, leading to fewer red blood cells, reduced haemoglobin concentration, and decreased haematocrit levels, potentially contributing to haematological disorders. This is particularly concerning for shift workers for example firefighters. While previous studies have explored sleep's adverse effects on various professions, research specific to firefighters is limited. This study investigates the relationship between sleep quality and haematological parameters among firefighters in Northeast Portugal. From a sample of 201 firefighters, variations in red blood cells, haemoglobin, and haematocrit values were linked to sleep quality. The study utilised non-parametric tests (Wilcoxon-Mann-Whitney, Spearman's correlation) to explore the connection between sleep quality and haematological profile. The impact of covariates on haematological parameters was assessed using non-parametric ANCOVA (Quade's). A multiple regression analysis was employed to further understand how sleep quality and various confounding variables impact haematological levels. Findings suggest a negative link between sleep quality and haematological levels, meaning that as sleep quality deteriorates, there is a tendency for haematological levels to decrease, as indicated by Spearman's correlation (rRBC = -0.157, pRBC = 0.026; rHb = -0.158, pHb = 0.025; rHCT = -0.175, pHCT = 0.013). As observed in scientific literature, the correlation found suggests a possible inhibition of erythropoiesis, the process responsible for red blood cell production. Despite firefighters presenting a haematological profile within the reference range (RBC: 5.1 × 106/mm3 (SD ± 0.4), Hb: 15.6 g/dL (SD ± 1.3), 47% (SD ± 1.0), there is already an observable trend towards lower levels. The analysis of co-variables did not reveal a significant impact of sleep quality on haematological levels. In conclusion, this study underscores the importance of sleep quality in determining haematological parameters among firefighters. Future research should investigate the underlying mechanisms and long-term implications of poor sleep quality on firefighter health. Exploring interventions to enhance sleep quality is vital for evidence-based strategies promoting firefighter well-being.

The Relationship Between Academic Stress, Sleep Quality, and Psychological Wellbeing in Pasifika and New Zealand European Students at the University of Otago

BACKGROUND

Pasifika students in New Zealand are overrepresented in poor academic outcomes, and their academic challenges may potentially influence their wellbeing. We aim to: 1) compare the academic stress, sleep quality, and psychological wellbeing of Pasifika and New Zealand European (NZE) anatomy students at the University of Otago, and 2) determine if academic stress mediates the association between their psychological wellbeing and sleep quality.

METHODS

We launched a brief online survey to Pasifika and NZE students in our department. The survey included basic demographics, Perception of Academic Stress Scale, Pittsburgh Sleep Quality Index, Hospital Anxiety and Depression Scale, a short loneliness scale, a reduced morningness-eveningness scale, and the Epworth Sleepiness Scale.

RESULTS

Perceived academic stress were comparable between NZE and Pasifika students, but Pasifika students reported poorer sleep quality than NZE students (t(113) = 14.41, P < .001). In addition, Pasifika students reported more loneliness (t(119) = 8.933, P < .001), less anxiety symptoms (t(120) = 2.469, P = .015), and less of a morning person (t(121) = 2.618, P = .010) than NZE students, but they had comparable depressive symptoms and daytime sleepiness. After controlling for age, ethnicity and gender, we found that academic stress fully mediated the relationship between anxiety or depressive symptoms and poor sleep quality. Furthermore, academic stress partially mediated the relationship between loneliness and poor sleep quality in our cohort.

CONCLUSION

Our findings highlight the importance for academic institutions to support students' wellbeing, including ethnic minority students such as Pasifika students in New Zealand.

Sex Differences in Temporal Sleep Patterns, Social Jetlag, and Attention in High School Adolescents

Insufficient sleep and irregular sleep hours are common in adolescents, who experience a delayed sleep phase due to biopsychosocial changes associated with puberty, resulting in later sleep times. However, early morning class hours shorten sleep duration on weekdays. This condition is harmful to cognitive performance, which may be accentuated in girls due to a greater sleep need and less resistance to sleep deprivation. In this study, we evaluated sex differences concerning temporal sleep patterns, social jetlag, and attention in high school adolescents attending morning classes. Students ( n  = 146 - F: 73-16.1 ± 0.8 years; M: 73-16.2 ± 0.9 years) completed a Health and Sleep questionnaire, kept a sleep diary for 10 days, which incorporated a Maldonado Sleepiness Scale, and performed a Continuous Performance Task. Girls went to bed earlier and woke up on weekends, and spent more time in bed at night and in 24 h on weekdays and weekends, while they also had a greater irregularity in wake-up times ( p  < 0.05). There were no differences between sexes in terms of social jetlag, sleep debt, and sleepiness upon awakening ( p  > 0.05). Regarding attention, the girls had a longer reaction time in phasic alertness ( p  < 0.01) and a tendency to have fewer errors in selective attention ( p  = 0.06). These results persisted when controlled for sleep parameters. Therefore, we suggest that girls have a greater sleep need and less resistance to sleep deprivation, while the differences in attention performance could be due to different strategies, the girls could be making a trade, increasing reaction time in favor of better accuracy, while the boys could be prioritizing a faster response time.

Study on the Profiles of Sleep Disorders, Associated Factors, and Pathways Among Gynecological Cancer Patients - A Latent Profile Analysis

Background

Gynecological cancer generally refers to malignant tumors in gynecology, commonly including cervical cancer, endometrial cancer, and ovarian cancer. Patients with gynecological cancer often suffer from sleep disorders after clinical treatment. Except for serious sleep disorders, female characteristics, family roles, and feudal beliefs make their self-stigma at a medium to high level, leading to huge pressure. This study aims to identify potential categories of sleep disorders, and analyze the relationship between self-stigma, perceived stress, and sleep disorders.

Methods

A cross-sectional study was conducted in 2021-2022. Two hundred and two patients' data were collected from ShengJing Hospital Affiliated to China Medical University in Liaoning, Shenyang by using paper questionnaires for face-to-face surveys. The survey tools included the Pittsburgh Sleep Quality Index (PSQI), the Perceived Stress Scale (PSS), and the Social Impact Scale (SIS). Potential profile analysis (LPA), multiple logistic regression analysis, and structural equation modeling (SEM) were performed by Mplus 8.3, SPSS 26.0, and Amos 24.0 statistical tools, respectively.

Results

Three latent patterns of sleep disorders were found: "Good Sleep group (42.5%)", "Sleep Deficiency group (32.4%)", and "Sleep Disturbance group (25.1%)". Patients with high perceived stress were more likely to report a moderate (OR=1.142, 95% CI: 1.061-1.230) or high (OR=1.455, 95% CI: 1.291-1.640) level of sleep disorders. Self-stigma did not have a direct effect on sleep disorders (0.055, P>0.05), but it could have indirect effect on sleep disorders through perceived stress (0.172, P<0.01).

Conclusion

The perceptions of sleep disorders among gynecological cancer patients varies and exhibits individual differences. Gynecological cancer patients who feels alienated or discriminated may cause high pressure. This internal pressure can exacerbate sleep disorders.

Device-assessed physical activity and sleep quality of post-COVID patients undergoing a rehabilitation program

BACKGROUND

An infection with SARS-CoV-2 can lead to persistent symptoms more than three months after the acute infection and has also an impact on patients' physical activity behaviour and sleep quality. There is evidence, that inpatient post-COVID rehabilitation can improve physical capacity and mental health impairments, but less is known about the change in physical behaviour and sleep quality.

METHODS

This longitudinal observational study used accelerometery to assess the level of physical activity and sleep quality before and after an inpatient rehabilitation program. The study sample consists of 100 post-COVID patients who acquired COVID-19 in the workplace. Group differences related to sex, age, COVID-19 severity, and pre-existing diseases were also analysed.

RESULTS

Level of physical activity and sleep quality didn't increase after rehabilitation. Overall, there is a high extent of inactivity time and poor sleep quality at both measurement points. Regarding group differences, male patients showed a significantly higher inactivity time before rehabilitation, and younger patients (< 55 years) spend significant more time in vigorous physical activity than older patients. Post-COVID patients with pre-existing cardiovascular, respiratory, and metabolic disease show slightly less physical activity than post-COVID patients without these comorbidities. Female patients and younger patients showed better sleep quality in some sleep parameters at both measurement points. However, no differences could be detected related to COVID-19 severity.

CONCLUSIONS

Ongoing strategies should be implemented to address the high amount of inactivity time and the poor sleep quality in post-COVID patients.

Insight into sleep quality and its relationship with emotional intelligence: results of a cross-sectional study among Italian university students

Background

This study aimed to investigate sleep habits and examine the relationship between sleep quality and its potential predictors, namely Emotional Intelligence (EI) and perceived health status.

Methods

The present cross-sectional study was conducted between February 13 and February 28, 2023, at the "Magna Græcia" University of Catanzaro, in the Southern part of Italy. The study involved undergraduate students who were 18 years or older, proficient in the Italian language, and with no restrictions on the major attended. They completed a self-administered survey on socio-demographic information, health status, sleep quality (Pittsburgh Sleep Quality Index-PSQI), EI, and perceived health status.

Results

The majority of the sample (59.6%) was enrolled in medical or life science majors. The results showed a high prevalence of poor sleep quality and sleep latency was identified as the most affected aspect of it. The female gender and the self-perceived health status were the strongest predictors of poor sleep quality. Poor sleepers showed lower emotional clarity, emotional repair, and total EI scores. Moreover, as age increased, the odds of being classified as a poor sleeper increased by 7%.

Conclusion

The survey highlights that poor sleep health is still a significant issue and empowering individuals to make proactive decisions to adopt healthy lifestyles in the early phase of life is of paramount importance. The study exhibited the interesting role of EI in influencing sleep quality, highlighting that when emotional events are insufficiently regulated, it may result in sleep disturbances. Therefore, the promotion of sleep quality requires an integrated yet innovative approach including emotion regulation.

Acute sleep deprivation reduces fear memories in male and female mice

Sleep problems are a prominent feature of mental health conditions including post-traumatic stress disorder (PTSD). Despite its potential importance, the role of sleep in the development of and/or recovery from trauma-related illnesses is not understood. Interestingly, there are reports that sleep deprivation immediately after a traumatic experience can reduce fear memories, an effect that could be utilized therapeutically in humans. While the mechanisms of this effect are not completely understood, one possible explanation for these findings is that immediate sleep deprivation interferes with consolidation of fear memories, rendering them weaker and more sensitive to intervention. Here, we allowed fear-conditioned mice to sleep immediately after fear conditioning during a time frame (18 hr) that includes and extends beyond periods typically associated with memory consolidation before subjecting them to 6 hr of sleep deprivation. Mice deprived of sleep with this delayed regimen showed dramatic reductions in fear during tests conducted immediately after sleep deprivation, as well as 24 hr later. This sleep deprivation regimen also increased levels of mRNA encoding brain-derived neurotrophic factor (BDNF), a molecule implicated in neuroplasticity, in the basolateral amygdala (BLA), a brain area implicated in fear and its extinction. These findings raise the possibility that the effects of our delayed sleep deprivation regimen are not due to disruption of memory consolidation, but instead are caused by BDNF-mediated neuroadaptations within the BLA that actively suppress expression of fear. Treatments that safely reduce expression of fear memories would have considerable therapeutic potential in the treatment of conditions triggered by trauma.

Sex-specific grey matter abnormalities in individuals with chronic insomnia

Previous studies have reported sex differences in altered brain function in patients with chronic insomnia (CI). However, sex-related alterations in brain morphology have rarely been investigated. This study aimed to investigate sex-specific grey matter (GM) alterations in patients with CI and to examine the relationship between GM alterations and neuropsychological assessments. Ninety-three (65 females and 28 males) patients and 78 healthy (50 females and 28 males) controls were recruited. Structural magnetic resonance imaging data were analysed using voxel-based morphometry to test for interactions between sex and diagnosis. Spearman's correlation was used to assess the associations among structure, disease duration, and sleep-, mood-, and cognition-related assessments. Males with CI showed reduced GM volume in the left inferior parietal lobe, left middle cingulate cortex, and right supramarginal gyrus. Females with CI showed increased GM volume in the right Rolandic operculum. Moreover, mood-related assessments were negatively correlated with GM volumes in the right supramarginal gyrus and left inferior parietal lobe in the male patients, and cognitive-related assessments were positively correlated with GM volumes in the Rolandic operculum in the female patients. Our findings indicate sex-specific alterations in brain morphology in CI, thereby broadening our understanding of sex differences in CI and potentially providing complementary evidence for the development of more effective therapies and individual treatments.

A sociodemographic index identifies non-biological sex-related effects on insomnia in the Hispanic Community Health Study/Study of Latinos

Background

Sex differences are related to both biological factors and the gendered environment. To untangle sex-related effects on health and disease it is important to model sex-related differences better.

Methods

Data came from the baseline visit of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), a longitudinal cohort study following 16,415 individuals recruited at baseline from four study sites: Bronx NY, Miami FL, San Diego CA, and Chicago IL. We applied LASSO penalized logistic regression of male versus female sex over sociodemographic, acculturation, and psychological factors jointly. Two "gendered indices", GISE and GIPSE, summarizing the sociodemographic environment (GISE, primary) and psychosocial and sociodemographic environment (GIPSE, secondary) associated with sex, were calculated by summing these variables, weighted by their regression coefficients. We examined the association of these indices with insomnia derived from self-reported symptoms assessed via the Women Health Initiative Insomnia Rating Scale (WHIIRS), a phenotype with strong sex differences, in sex-adjusted and sex-stratified analyses. All analyses were adjusted for age, Hispanic/Latino background, and study center.

Results

The distribution of GISE and GIPSE differed by sex with higher values in male individuals, even when constructing and validating them on separate, independent, subsets of HCHS/SOL individuals. In an association model with insomnia, male sex was associated with lower likelihood of insomnia (odds ratio (OR)=0.60, 95% CI (0.53, 0.67)). Including GISE in the model, the association was slightly weaker (OR=0.63, 95% CI (0.56, 0.70)), and weaker when including instead GIPSE in the association model (OR=0.78, 95% CI (0.69, 0.88)). Higher values of GISE and of GIPSE, more common in male sex, were associated with lower likelihood of insomnia, in analyses adjusted for sex (per 1 standard deviation of the index, GISE OR= 0.92, 95% CI (0.87, 0.99), GIPSE OR=0.65, 95% CI (0.61, 0.70)).

Conclusions

New measures such as GISE and GIPSE capture sex-related differences beyond binary sex and have the potential to better model and inform research studies of health. However, such indices do not account for gender identity and may not well capture the environment experienced by intersex and non-binary persons.

Association between phthalates and sleep problems in the U.S. adult females from NHANES 2011-2014

There is little research on the relationship between phthalates exposure and sleep problems in adult females, with existing studies only assessing the association between exposure to individual phthalates with sleep problems.     We aimed to analyse the relationship between phthalates and sleep problems in 1366 US females aged 20 years and older from the 2011-2014 National Health and Nutrition Examination Survey (NHANES) by age stratification. Multivariate logistic regression showed that the fourth quartile of MECPP increased the risk of sleep problems in females aged 20-39 compared with the reference quartile (OR: 1.87, 95% CI: 1.14, 3.08). The WQS index was significantly associated with the sleep problems in females aged 20-39. In the BKMR, a positive overall trend between the mixture and sleep problems in females aged 20-39. In this study, we concluded that phthalates might increase the risk of sleep problems in females aged 20-39.

The association of short and long sleep with mortality in men and women

Both short (< 6 hr) and long (> 8 hr) sleep are associated with increased mortality. We here investigated whether the association between sleep duration and all-cause, cardiovascular disease and cancer mortality differs between men and women. A cohort of 34,311 participants (mean age and standard deviation = 50.5 ± 15.5 years, 65% women), with detailed assessment of sleep at baseline and up to 20.5 years of follow-up (18 years for cause-specific mortality), was analysed using Cox proportional hazards model to estimate HRs with 95% confidence intervals. After adjustment for covariates, all-cause, cardiovascular disease and cancer mortalities were increased for both < 5 hr and ≥ 9 hr sleep durations (with 6 hr as reference). For all-cause mortality, women who slept < 5 hr had a hazard ratio = 1.54 (95% confidence interval = 1.32-1.80), while the corresponding hazard ratio was 1.05 (95% confidence interval = 0.88-1.27) for men, the interaction being significant (p < 0.05). For cardiovascular disease mortality, exclusion of the first 2 years of exposure, as well as competing risk analysis eliminated the originally significant interaction. Cancer mortality did not show any significant interaction. Survival analysis of the difference between the reference duration (6 hr) and the short duration (< 5 hr) during follow-up showed a gradually steeper reduction of survival time for women than for men for all-cause mortality. We also observed that the lowest cancer mortality appeared for the 5-hr sleep duration. In conclusion, the pattern of association between short sleep duration and all-cause mortality differed between women and men, and the difference between men and women increased with follow-up time.

Urbanisation negatively impacts sleep health and mood in adolescents: a comparative study of female students from city and rural schools of North India

This study investigated the impact of social settings on sleep, physical and mental health in female adolescents of North India (latitude 29.5 oN; longitude 77.5 oE). Using a battery of questionnaires, we compared the chronotype, sleep-wake pattern, sleep health (e.g. sleep quality, daytime sleepiness and fatigue) and mood (via depression, anxiety and stress symptoms) in female students (age 14-18 years) from rural (N = 719) and urban (N = 1033) schools separated by about 35 km, but families had almost similar socio-demographic details. The morning type was prevalent amongst rural, whilst the evening type was prevalent amongst urban students who also had access to smart phones, suggesting a possible greater use of the internet. There were greater negative sleep effects, daytime sleepiness, overall poor sleep quality, higher fatigue and anxiety levels in urban than the rural cohort. Interestingly, these measures also differed between school days and free days, suggesting an impact of the conflict between internal biological and social timings (= social jet lag). We also found a significant relationship between chronotype, internet addiction, mood-related parameters and measures of sleep health. Overall, these results suggest a possible impact of social settings on sleep health and mood-related behaviours in female adolescents.

Proof-of-concept evidence for high-density EEG investigation of sleep slow wave traveling in First-Episode Psychosis

Schizophrenia is thought to reflect aberrant connectivity within cortico-cortical and reentrant thalamo-cortical loops, which physiologically integrate and coordinate the function of multiple cortical and subcortical structures. Despite extensive research, reliable biomarkers of such "dys-connectivity" remain to be identified at the onset of psychosis, and before exposure to antipsychotic drugs. Because slow waves travel across the brain during sleep, they represent an ideal paradigm to study pathological conditions affecting brain connectivity. Here, we provide proof-of-concept evidence for a novel approach to investigate slow wave traveling properties in First-Episode Psychosis (FEP) with high-density electroencephalography (EEG). Whole-night sleep recordings of 5 drug-naïve FEP and 5 age- and gender-matched healthy control subjects were obtained with a 256-channel EEG system. One patient was re-recorded after 6 months and 3 years of continuous clozapine treatment. Slow wave detection and traveling properties were obtained with an open-source toolbox. Slow wave density and slow wave traveled distance (measured as the line of longest displacement) were significantly lower in patients (p < 0.05). In the patient who was tested longitudinally during effective clozapine treatment, slow wave density normalized, while traveling distance only partially recovered. These preliminary findings suggest that slow wave traveling could be employed in larger samples to detect cortical "dys-connectivity" at psychosis onset.

Sex-related differential item functioning of the Jenkins Sleep Scale: a cross-sectional study among 77 967 employees in the Finnish public sector

OBJECTIVES

To investigate if the Jenkins Sleep Scale (JSS) demonstrates sex-related differential item functioning (DIF).

DESIGN

Cross-sectional study.

SETTING

Survey data from the Finnish Public Sector study (2015-2017).

PARTICIPANTS

77 967 employees in the Finnish public sector, with a mean age of 51.9 (SD 13.1) years and 82% women.

OUTCOME MEASURES

Item response theory estimates: difficulty and discrimination parameters of the JSS and differences in these parameters between men and women.

RESULTS

The mean JSS total score was 6.4 (4.8) points. For all four items of the JSS, the difficulty parameter demonstrated a slight shift towards underestimation of the severity of sleep difficulties. The discrimination ability of all four items was moderate to high. For the JSS composite score, overall discrimination ability was moderate (0.98, 95% CI 0.97 to 0.99). Mild uniform DIF (p<0.001) was seen: two items showed better discrimination ability among men and two others among women.

CONCLUSIONS

The JSS showed overall good psychometric properties among this healthy population of employees in the Finnish public sector. The JSS was able to discriminate people with different severities of sleep disturbances. However, when using the JSS, the respondents might slightly underestimate the severity of these disturbances. While the JSS may produce slightly different results when answered by men and women, these sex-related differences are probably negligible when applied to clinical situations.

Sex-specific regulation of the cortical transcriptome in response to sleep deprivation

Multiple studies have documented sex differences in sleep behaviour, however, the molecular determinants of such differences remain unknown. Furthermore, most studies addressing molecular mechanisms have been performed only in males, leaving the current state of knowledge biased towards the male sex. To address this, we studied the differences in the transcriptome of the cerebral cortex of male and female C57Bl/6 J mice after 6 h of sleep deprivation. We found that several genes, including the neurotrophin growth factor Bdnf, immediate early genes Fosb and Fosl2, and the adenylate cyclase Adcy7 are differentially upregulated in males compared to females. We identified the androgen-receptor activating transcription factor EZH2 as the upstream regulatory element specifying sex differences in the sleep deprivation transcriptome. We propose that the pathways downstream of these transcripts, which impact on cellular re-organisation, synaptic signalling, and learning may underpin the differential response to sleep deprivation in the two sexes.

Association of sleep duration and quality with serum testosterone concentrations among men and women: NHANES 2011-2016

BACKGROUND

The association between testosterone concentrations and sleep duration is poorly understood.

OBJECTIVE

To evaluate the association between sleep duration and quality with serum testosterone concentrations and its variation by sex and age.

METHODS

Data were analyzed for 8748 men and women (≥20 years old) who participated in the cycles of the National Health and Nutrition Examination Survey 2011-2016, a cross-sectional study. Total testosterone (ng/dL) was measured and categorized (low, moderate, and high) based on established cut-offs for men and its tertile distribution among women. Sleep duration was classified as ≤6, 7-8, and ≥9 h. Sleep quality was classified as poor or good based on the frequency of trouble falling or staying asleep or sleeping too much. Weighted multivariable adjusted and multinomial logistic regression models were conducted to assess these associations.

RESULTS

The association between sleep duration and testosterone concentrations, varied according to sex and age. Sleep deprivation (≤6 h) was associated with high testosterone (odds ratio = 3.62; 95% confidence interval: 1.37, 9.53) among young men (20-40 years old); meanwhile, middle-aged men (41-64 years old) who reported more sleep duration had low testosterone (odds ratio = 2.03; 95% confidence interval: 1.10, 3.73). A J-shaped association between sleep duration and low testosterone (odds ratio≤6 h  = 1.57; 95% confidence interval: 1.10, 2.27; odds ratio≥9  h  = 2.06; 95% confidence interval: 1.18, 3.59) was observed in women aged 41-64 years. We did not find any association with sleep quality.

CONCLUSION

The association of sleep duration with serum testosterone concentrations varies with sex and age group. Prospective studies are warranted to confirm these sex and age group differences.

Sleep duration and perceptions of sleep quality in British Army recruits during basic training - an observational analysis

Introduction

Sleep is critical to the health, wellbeing and performance of military personnel during basic training. This two-part study evaluated sleep-wake patterns and sleep disturbances in junior soldiers (JS) and infantry recruits in Autumn 2021 (study 1), and non-infantry recruits in spring 2022 (study 2).

Methods

During studies 1 and 2, validated wearable technology combined with a sleep diary was used to quantify sleep-wake indices, sleep disturbances and perceptions of sleep quality. Sleep diary data was analysed descriptively. A series of repeated-measures ANOVAs examined differences in objective sleep-wake indices. Correlation analysis determined associations between time in bed (TIB) and total sleep time (TST).

Results

Significant (p < 0.05) differences in most sleep-wake indices were observed between weeks of basic training for all cohorts. Strong positive correlations between TIB and TST were observed for each cohort across basic training (r = 0.681 - 0.970, p < 0.001), with longer TST associated with greater TIB. The mean±SD sleep duration (hours and mins [hm]) for JS (06:22 ± 00:27hm), non-infantry (05:41 ± 00:47hm) and infantry (05:46 ± 00:34hm) recruits across basic training was consistently below national recommendations. The mean±SD bed and wake times for JS (bedtime: 23:01 ± 00:32hm; awake: 05:34 ± 00:10hm), non-infantry (bedtime: 23:38 ± 01:09hm; awake: 04:47 ± 00:58hm), and infantry (bedtime: 23:13 ± 00:29hm; awake: 05:38 ± 00:26hm) recruits varied across weeks of basic training, with over 80% reporting "fairly bad" or "very bad" sleep quality and frequent periods of "dozing off" during daytime activity. The most commonly reported sleep disturbing factors identified during basic training involved: late-night military admin (e.g., ironing, boot cleaning, kit set up etc), early morning wake times, extraneous noise, light and hot room temperatures within the primary sleeping environment, bed/mattress discomfort, muscle soreness and feelings of stress and anxiety.

Discussion/Conclusion

Our findings contribute to the existing evidence that long-term sleep loss is pervasive during initial military training programmes. The average sleep durations indicate chronic and unrecoverable sleep loss which would be expected to significantly impair physical and cognitive military performance, and increase the risk of injury, illness and attrition rates during basic training. Changes in the design and scheduling of basic training programmes to enable, at the least, minimum sleep recommendations to be met, and to improve sleep hygiene in the primary sleeping environment are warranted.

The association between energy-adjusted dietary inflammatory index and physical activity with sleep quality: a cross-sectional study

BACKGROUND

The study aimed to assess the independent and interactive association of energy-adjusted dietary inflammatory index (E-DII) and physical activity (PA) with sleep quality.

METHOD

A cross-sectional study was conducted on the 2466 participants (60% women). A 116-item food frequency questionnaire (FFQ) was applied to calculate E-DII, the International Physical Activity Questionnaire (IPAQ) long form for PA, and the Pittsburgh sleep quality index (PSQI) to assess sleep quality were collected via interview. Multivariate logistic regression was applied to assess independent and interactive associations of E-DII and PA with sleep quality.

RESULT

No significant association was observed between E-DII and sleep quality (OR: 0.96, 95% CI: 0.92_1.01). Also, there was no significant association between the levels of PA and sleep quality. Women had 70% increased odds for poor sleep quality (OR: 1.7, 95% CI: 1.39_2.09) compared with men. No interactive association was observed between E-DII and PA levels with sleep quality.

CONCLUSION

No significant association was observed between E-DII and PA levels with sleep quality. The study indicates a gender difference in sleep quality. Future prospective studies are required to confirm these findings.

Behavioral phenotyping based on physical inactivity can predict sleep in female rats before, during, and after sleep disruption

BACKGROUND

A noninvasive method that can accurately quantify sleep before, during, and after sleep disruption (SD) has not been validated in female rats across their estrous cycle. In female rats, we hypothesized that the duration of physical inactivity (PIA) required to predict sleep would 1) change with the differences in baseline sleep between the circadian and estrous cycle phases and 2) predict sleep and the change in sleep (Δsleep) before, during, and after SD independent of circadian and estrous cycle phase.

NEW METHODS

EEG, EMG, physical activity and estrous cycle phase were measured in female Sprague-Dawley rats before, during, and after SD. Sleep was determined by two methods [EEG/EMG and a duration of continuous PIA (i.e., PIA criterion)]. Reliability between the methods was tested with a previously validated criterion (40 s). Sensitivity analyses and criterion-related validity analyses for sleep during SD and recovery were conducted across multiple PIA criteria (10 s-120 s). Predictability between the two methods and Δsleep was calculated.

RESULTS/COMPARISON WITH EXISTING METHODS

Three criteria (10 s, 20 s, 30 s) predicted baseline sleep independent of circadian and estrous cycle phase. Sleep during SD and recovery were predicted by two criteria (30 s and 10 s). Δsleep between study periods was not reliably predicted by a single PIA criterion.

CONCLUSION

PIA predicted sleep independent of estrous cycle phase in female rats. However, the specific criterion was dependent upon the study period (before, during, and after SD) and circadian phase. Thus, prior work validating a PIA criterion in male rodents is not applicable to the female rat.

Validation of the Chinese version of the Sleep Regularity Questionnaire (SRQ) and analysis of influencing factors

BACKGROUND

Currently, there is no instrument to measure sleep regularity in China. In this study, the Sleep Regularity Questionnaire（SRQ） was translated into Chinese, tested for reliability and validity, and analyzed for factors affecting sleep regularity.

METHODS

The English version of the SRQ was translated into Chinese, and a total of 3642 individuals were included in this research. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were used to examine the underlying factor structure of the Chinese version of the SRQ and to measure its reliability and validity. In addition, the correlations between sleep regularity and general information, personal habits, self-control, stress, anxiety, and depression were explored.

RESULTS

The Cronbach's α of the Chinese SRQ was 0.858, supporting the two-factor structure. Sleep regularity was statistically different between gender and ethnicity (p < 0.05), and personal habits (exercise, continued eating after dinner, smoking and drinking) had an effect on sleep regularity. Sleep regularity was positively associated with individual self-control and negatively associated with stress, anxiety, and depression.

CONCLUSIONS

The Chinese version of the SRQ has excellent reliability and validity. There are two dimensions, namely circadian regularity and sleep continuity regularity, which can be used to assess the sleep regularity of Chinese adults. The results of this study showed that males and Han Chinese having better sleep regularity. And people with good lifestyle habits and greater self-control sleep more regularly, while stress, anxiety and depression can affect individuals' sleep regularity.

Gender differences in the relationship between sleep and age in a Brazilian cohort: the Baependi Heart Study

Gender and age are well-established determinants of health and sleep health that influence overall health, which also often varies by gender and age. Sleep architecture is an important component of sleep health. The goal of this analysis was to examine whether associations between age and sleep stages differ by gender in the absence of moderate-severe obstructive sleep apnea (OSA) in a rural setting in Brazil. This study conducted polysomnography recordings in the Baependi Heart Study, a cohort of Brazilian adults. Our sample included 584 women and 309 men whose apnea-hypopnea index was ≤15 events/h. We used splines to distinguish non-linear associations between age, total sleep time, wake after sleep onset (WASO), N2, N3, and rapid-eye-movement sleep. The mean (standard deviation; range) age was 47 (14; 18-89) years. All sleep outcomes were associated with age. Compared to men, women had more N3 sleep and less WASO after adjusting for age. Model-based comparisons between genders at specific ages showed statistically higher mean WASO for men at ages 60 (+13.6 min) and 70 years (+19.5 min) and less N3 for men at ages 50 (-13.2 min), 60 (-19.0 min), and 70 years (-19.5 min) but no differences at 20, 30, 40 or 80 years. The other sleep measures did not differ by gender at any age. Thus, even in the absence of moderate-severe OSA, sleep architecture was associated with age across adulthood, and there were gender differences in WASO and N3 at older ages in this rural community.

Effects of acute bouts of evening resistance or endurance exercises on sleep EEG and salivary cortisol

Introduction: Deleterious effects of exercise close to bedtime could be due to increased physiological arousal that can be detected during sleep using sleep spectral analysis. Resistance and endurance exercises have different effects on cortisol release that may lead them to impact sleep spectral signatures differently. The present study aimed to investigate the effects of two types of evening exercise on sleep architecture, sleep spectral parameters and salivary cortisol. Methods: Young healthy participants came to our laboratory to undergo 3 counterbalanced pre-sleep conditions that started 1 h before bedtime (a resistance and an endurance exercise conditions of 30 min duration, identical in terms of workload; and a control condition) followed by polysomnographic recordings. Results were compared between the three conditions for 16 participants. Results: Sleep efficiency was lower after both endurance and resistance exercise than after the control condition. Total sleep time was lower after endurance exercise compared to the control condition. Sleep spectral analyses showed that both endurance and resistance exercises led to greater alpha power during N1 sleep stage and greater theta power during N2 sleep stage compared to the control condition. The endurance exercise led to greater beta power during N2 sleep stage, greater alpha power during REM sleep, and higher cortisol levels compared to the control condition (trend), and compared to the resistance exercise condition (significant). The resistance exercise led to lower beta power during N2 sleep stage than the control condition and lower cortisol levels than the endurance exercise condition. Discussion: This study underlines significant modifications of sleep quality and quantity after both moderate evening endurance and resistance exercises. Still, these effects cannot be considered as deleterious. In contrast to the resistance exercise, endurance exercise led to an increase in sleep EEG activity associated with hyperarousal during sleep and higher cortisol levels, suggesting an hyperarousal effect of endurance exercise performed in the evening. These results align with previous warning about the arousal effects of evening exercise but do not support the notion of deleterious effects on sleep. While these results provide support for the physiological effects of evening exercises on sleep, replication with larger sample size is needed.

Relationship between sleep quality and marital satisfaction of working women during the premenopausal period

Sleep disorders can adversely affect physical, sexual, and marital health, particularly among middle-aged women. This study aimed to determine the relationship between sleep quality and marital satisfaction of working women during the premenopausal period. In this cross-sectional study, we selected 150 women working at Shiraz University of Medical Sciences in Iran was selected using random cluster sampling. A demographic information form, the Pittsburgh Sleep Quality Index (PSQI), and the Evaluation and Nurturing Relationship Issues, Communication, and Happiness (ENRICH) marital satisfaction scale were used for data collection. The Data were analyzed using SPSS.22 software at a significance level of P < 0.05. Multiple linear regression analysis was employed to predict sleep quality based on marital satisfaction. Our results showed that 79 (52.7%) of the participants had undesirable sleep quality, 87 (58%) had high marital satisfaction, and 32 (21.3%) had very high marital satisfaction. Regression analysis revealed that the total marital satisfaction score could not predict the sleep quality score of the participants. However, as dimensions of marital satisfaction, personality issues negatively (β = 0.327, P < 0.05) and ideological orientation positively (β = 0.336, P < 0.01) predicted the sleep quality score. Based on the prediction of the sleep quality score by personality issues and ideological orientations among the dimensions of marital satisfaction, it seems that life skills training, especially in these two dimensions, may improve the quality of sleep and, as a result, the physical and mental health of working women.

Interactive effects of pain and arousal state on heart rate and cortical activity in the mouse anterior cingulate and somatosensory cortices

Sensory disconnection is a hallmark of sleep, yet the cortex retains some ability to process sensory information. Acute noxious stimulation during sleep increases the heart rate and the likelihood of awakening, indicating that certain mechanisms for pain sensing and processing remain active. However, processing of somatosensory information, including pain, during sleep remains underexplored. To assess somatosensation in natural sleep, we simultaneously recorded heart rate and local field potentials in the anterior cingulate (ACC) and somatosensory (S1) cortices of naïve, adult male mice, while applying noxious and non-noxious stimuli to their hind paws throughout their sleep-wake cycle. Noxious stimuli evoked stronger heart rate increases in both wake and non-rapid eye movement sleep (NREMS), and resulted in larger awakening probability in NREMS, as compared to non-noxious stimulation, suggesting differential processing of noxious and non-noxious information during sleep. Somatosensory information differentially reached S1 and ACC in sleep, eliciting complex transient and sustained responses in the delta, alpha, and gamma frequency bands as well as somatosensory evoked potentials. These dynamics depended on sleep state, the behavioral response to the stimulation and stimulation intensity (non-noxious vs. noxious). Furthermore, we found a correlation of the heart rate with the gamma band in S1 in the absence of a reaction in wake and sleep for noxious stimulation. These findings confirm that somatosensory information, including nociception, is sensed and processed during sleep even in the absence of a behavioral response.

The Effect of Different Types of Exercise on Sleep Quality and Architecture in Parkinson Disease: A Single-Blinded Randomized Clinical Trial Protocol

OBJECTIVES

The purpose of this trial is to (1) determine the best exercise modality to improve sleep quality and sleep architecture in people with Parkinson disease (PD); (2) investigate whether exercise-induced improvements in sleep mediate enhancements in motor and cognitive function as well as other non-motor symptoms of PD; and (3) explore if changes in systemic inflammation after exercise mediate improvements in sleep.

METHODS

This is a multi-site, superiority, single-blinded randomized controlled trial. One hundred fifty persons with PD and sleep problems will be recruited and randomly allocated into 4 intervention arms. Participants will be allocated into 12 weeks of either cardiovascular training, resistance training, multimodal training, or a waiting list control intervention. Assessments will be conducted at baseline, immediately after each intervention, and 8 weeks after each intervention by blinded assessors. Objective sleep quality and sleep architecture will be measured with polysomnography and electroencephalography. Motor and cognitive function will be assessed with the Unified PD Rating Scale and the Scale for Outcomes in PD-Cognition, respectively. Subjective sleep quality, fatigue, psychosocial functioning, and quality of life will be assessed with questionnaires. The concentration of inflammatory biomarkers in blood serum will be assessed with enzyme-linked immunosorbent assays.

IMPACT

This study will investigate the effect of different types of exercise on sleep quality and architecture in PD, exploring interactions between changes in sleep quality and architecture with motor and cognitive function and other non-motor symptoms of the disease as well as mechanistic interactions between systemic inflammation and sleep. The results will provide important practical information to guide physical therapists and other rehabilitation professionals in the selection of exercise and the design of more personalized exercise-based treatments aimed at optimizing sleep, motor, and cognitive function in people with PD.

The Two Fundamental Shapes of Sleep Heart Rate Dynamics and Their Connection to Mental Health in College Students

Introduction

Wearable devices are rapidly improving our ability to observe health-related processes for extended durations in an unintrusive manner. In this study, we use wearable devices to understand how the shape of the heart rate curve during sleep relates to mental health.

Methods

As part of the Lived Experiences Measured Using Rings Study (LEMURS), we collected heart rate measurements using the Oura ring (Gen3) for over 25,000 sleep periods and self-reported mental health indicators from roughly 600 first-year university students in the USA during the fall semester of 2022. Using clustering techniques, we find that the sleeping heart rate curves can be broadly separated into two categories that are mainly differentiated by how far along the sleep period the lowest heart rate is reached.

Results

Sleep periods characterized by reaching the lowest heart rate later during sleep are also associated with shorter deep and REM sleep and longer light sleep, but not a difference in total sleep duration. Aggregating sleep periods at the individual level, we find that consistently reaching the lowest heart rate later during sleep is a significant predictor of (1) self-reported impairment due to anxiety or depression, (2) a prior mental health diagnosis, and (3) firsthand experience in traumatic events. This association is more pronounced among females.

Conclusion

Our results show that the shape of the sleeping heart rate curve, which is only weakly correlated with descriptive statistics such as the average or the minimum heart rate, is a viable but mostly overlooked metric that can help quantify the relationship between sleep and mental health.

Nightmare distress, insomnia and resilience of nursing staff in the post-pandemic era

Introduction

The pandemic has led to notable psychological challenges among healthcare professionals, including nurses.

Objective

Our aims of this study were to assess insomnia and nightmare distress levels in nurses and investigate their association with mental resilience.

Methods

Nurses participated in an online survey, which included the Nightmare Distress Questionnaire (NDQ), Brief Resilience Scale (BRS) and Athens Insomnia Scale (AIS). Demographic information, such as age, professional experience and gender, was also collected.

Results

The study included 355 female and 78 male nurses. Findings revealed that 61.4% had abnormal AIS scores, 7% had abnormal NDQ scores and 25.4% had low BRS scores. Female nurses had higher AIS and NDQ scores but lower BRS scores compared to males. BRS demonstrated negative correlations with both AIS and NDQ. Multiple regression analysis indicated that NDQ accounted for 24% of the AIS variance, with an additional 6.5% explained by the BRS. BRS acted as a mediator, attenuating the impact of nightmares on insomnia, with gender moderating this relationship.

Conclusions

Nursing staff experienced heightened sleep disturbances during the pandemic, with nightmares and insomnia being prevalent. Nightmares significantly contributed to insomnia, but mental resilience played a vital role in mitigating this effect. Strategies are warranted to address the pandemic's psychological impact on nursing professionals.

The Effects of Hormonal Contraceptives on the Sleep of Women of Reproductive Age

Research about the effects of hormonal contraceptives on sleep has been performed but is subjected to important levels of methodological heterogeneity. Hormonal contraceptives impact sleep, but the direction of this association is not clear. Most studies describe a negative sleep profile among contraceptive users, including increased sleepiness, insomnia symptoms, decreased sleep efficiency, and a reduced overall sleep quality. Hormonal intrauterine contraceptives are associated with less negative effects. More research on the field, especially randomized controlled trials, is needed to increase the level and certainty of evidence about the effects of hormonal contraceptives on sleep.

Dysmenorrhea and Sleep: A Review

This review encompasses the clinical features and relevance to investigate sleep in women with dysmenorrhea. Dysmenorrhea is a prevalent gynecologic dysfunction that affects the social and professional lives of women. It can occur at every menstrual cycle, depending on the cause and psychologic factors. Studies have reported poor sleep and insomnia symptoms in dysmenorrhea condition, which may intensify the dysmenorrhea manifestation and interfere negatively to its treatment. There is an urgent need to identify the main cause of this dysfunction and provide efficient treatments to minimize the detrimental effects of dysmenorrhea in quality of life of these women.

Night Shift Work and Sleep Disturbances in Women: A Scoping Review

This scoping review aimed to synthesize evidence on sleep disturbances in female shift workers. The update Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews was used. Twelve studies were included, four of which used actigraphy to assess sleep duration, efficiency, and latency. Seven studies evaluated the quality of sleep and three verified the sleepiness of women. This review adds to the body of evidence as the findings are homogeneous and allow a robust conclusion, suggesting that night shift work may be a potential factor for adverse effects on sleep of female shift workers.

The Menstrual Cycle and Sleep

Aspects of sleep change across the menstrual cycle in some women. Poorer sleep quality in the premenstrual phase and menstruation is common in women with premenstrual symptoms or painful menstrual cramps. Although objective sleep continuity remains unchanged across the regular, asymptomatic menstrual cycle, activity in the sleep electroencephalogram varies, with a prominent increase in sleep spindle activity in the postovulatory luteal phase, when progesterone is present, relative to the follicular phase. Menstrual cycle phase, reproductive stage, and menstrual-related disorders should be considered when assessing women's sleep complaints.

The relationship between body mass index and sleep in women with risk factors for gestational diabetes mellitus

Background

Both obesity and sleep disorders are common among women during pregnancy. Although prior research has identified a relationship between obesity and sleep disorders, those findings are from women later in pregnancy.

Objective

To explore the relationships between self-reported sleep duration, insufficient sleep and snoring with body mass index (BMI) among multiethnic women at risk of gestational diabetes mellitus (GDM)in early pregnancy.

Methods

Cross-sectional study of baseline data from women at risk of GDM enrolled in the Treatment of BOoking Gestational diabetes Mellitus (TOBOGM) multicentre trial across 12 Australian/Austrian sites. Participants completed a questionnaire before 20 weeks' gestation to evaluate sleep. BMI <25 kg/m2 served as the reference group in multivariable logistic regression.

Results

Among the 2865 women included, the prevalence of overweight and obesity classes I-III was 28%, 19%, 11% and 12%, respectively. There was no relationship between sleep duration and BMI. The risk of insufficient sleep >5 days/month was higher in class II and class III obesity (1.38 (1.03-1.85) and 1.34 (1.01-1.80), respectively), and the risk of snoring increased as BMI increased (1.59 (1.25-2.02), 2.68 (2.07-3.48), 4.35 (3.21-5.88) to 4.96 (3.65-6.74), respectively)).

Conclusions

Obesity is associated with insufficient sleep among pregnant women at risk of GDM. Snoring is more prevalent with increasing BMI.

Selection of genetic instruments in Mendelian randomisation studies of sleep traits

This review explores the criteria used for the selection of genetic instruments of sleep traits in the context of Mendelian randomisation studies. This work was motivated by the fact that instrument selection is the most important decision when designing a Mendelian randomisation study. As far as we are aware, no review has sought to address this to date, even though the number of these studies is growing rapidly. The review is divided into the following sections which are essential for genetic instrument selection: 1) Single-gene region vs polygenic analysis; 2) Polygenic analysis: biologically-vs statistically-driven approaches; 3) P-value; 4) Linkage disequilibrium clumping; 5) Sample overlap; 6) Type of exposure; 7) Total (R2) and average strength (F-statistic) metrics; 8) Number of single-nucleotide polymorphisms; 9) Minor allele frequency and palindromic variants; 10) Confounding. Our main aim is to discuss how instrumental choice impacts analysis and compare the strategies that Mendelian randomisation studies of sleep traits have used. We hope that our review will enable more researchers to take a more considered approach when selecting genetic instruments for sleep exposures.

Associations between weekend catch-up sleep and health-related quality of life with focusing on gender differences

This study investigated associations between weekend catch-up sleep (WCUS) and health-related quality of life (HRQoL) in 15,837 participants from the 7th (2016-2018) Korea National Health and Nutrition Examination Survey. We categorized WCUS durations into four groups: none (≤ 0 h [h]), short (> 0 h, ≤ 1 h), medium (> 1 h, ≤ 2 h), and long (> 2 h), and performed complex samples logistic regression and likelihood ratio χ2 test. The study found significant associations in women for the European Quality of Life-5 Dimensions (EQ-5D) index and three EQ-5D subdomains (self-care, usual activities, and anxiety/depression) with the WCUS durations, but no significant association in men. Compared to the non-WCUS, the short or medium WCUS was positively associated with the EQ-5D index and EQ-5D subdomains (usual activities and anxiety/depression) in women, while the long WCUS significantly reduced the quality of life in the self-care domain. In an additional subgroup analysis by age, middle-aged and elderly women had a more noticeable effect of WCUS on HRQoL than young women, and the short or medium WCUS improved HRQoL in middle-aged and elderly women in general. Therefore, we recommend appropriate WCUS durations to improve HRQoL, considering both gender and age.

Effects of the COVID-19 pandemic on mental health and sleep quality in the Chinese general populations during sporadic and outbreak periods

The different coronavirus disease 2019 (COVID-19) outbreak patterns may have different impact on the mental health, but there is no such report at present. This study was aimed to investigate general populations mental health and sleep quality during the sporadic and outbreak of COVID-19 in Tianjin of China. Two cross-sectional studies included 1090 participants during the COVID-19 sporadic period from 28th January to 28th February 2022 and 2036 participants during the COVID-19 outbreak period from 1st January to 1st February 2023. We used the propensity score matching method to match the 2 samples (sporadic and outbreak group) with a ratio of 1:1. Finally, 1087 participants were included in each group. The demographics, Patient Health Questionnaire-9, Generalized Anxiety Disorder Scale-7, Connor-Davidson Resilience Scale, and Pittsburgh Sleep Quality Index were collected from all participants. There was a significant difference between the sporadic and outbreak groups for COVID-19-infected status, anxiety levels, sleep quality, and phycological resilience (all P < .05). Logistic regression analysis showed that female (P < .05) and depression status (P < .05) were the risk factors for the incidence rate of anxiety and poor sleep quality in sporadic group, and outbreak group, while phycological resilience were robust related to the sleep quality (P < .01). Poor sleep quality (P < .01) was related to the incidence of anxiety in sporadic group but not the outbreak group; anxiety levels (P < .01) were related to sleep quality in sporadic group but not the outbreak group. During the COVID-19 pandemic, general populations experienced high anxiety and poor sleep quality incidence rates, especially in the outbreak period. Different risk models for anxiety and sleep quality were found in the different outbreak patterns.

Rest-activity rhythms across the lifespan: cross-sectional findings from the US representative National Health and Nutrition Examination Survey

STUDY OBJECTIVES

Rest-activity rhythms (RAR) may mark development, aging, and physical and mental health. Understanding how they differ between people may inform intervention and health promotion efforts. However, RAR characteristics across the lifespan have not been well-studied. Therefore, we investigated the association between RAR measures with demographic and lifestyle factors in a US nationally representative study.

METHODS

RAR metrics of interdaily stability (IS), intradaily variability (IV), relative amplitude (RA), and mean amplitude and timing of high (M10) and low (L5) activity were derived from 2011 to 2012 and 2013 to 2014 National Health and Nutrition Examination Survey (NHANES) actigraphy data. Population-weighted linear and logistic regression models were fit to examine the associations of age, gender, smoking, alcohol, season, body mass index (BMI), income-to-poverty ratio, and race/ethnicity with RAR. Significance was based on a false-discovery rate-corrected P-value of <0.05.

RESULTS

Among n = 12 526 NHANES participants (3-≥80 years), IS (higher = greater day-to-day regularity) and RA (higher = greater rhythm strength) generally decreased with age and were lower among males, whereas IV (higher = greater rhythm fragmentation) increased with age (p < 0.05). Dynamic changes in RAR trajectories were observed during childhood and adolescence. Income, BMI, smoking, and alcohol use were associated with RAR metrics, as well as season among children and teenagers (p < 0.05). RAR also differed by race/ethnicity (p < 0.05), with trajectories initially diverging in childhood and continuing into adulthood.

CONCLUSIONS

RAR differed by demographic and health-related factors, representing possible windows for public health intervention and sleep health promotion. RAR differences by race/ethnicity begin in childhood, are evident in early adolescence, and persist throughout adulthood.

Overall Obesity Not Abdominal Obesity Has a Causal Relationship with Obstructive Sleep Apnea in Individual Level Data

Objective

Both obstructive sleep apnea (OSA) and obesity are highly prevalent worldwide, and are intrinsically linked. Previous studies showed that obesity is one of the major risk factors for OSA, but the causality of the relationship is still unclear. The study was to investigate the causal relationships of overall obesity and abdominal obesity with OSA and its quantitative traits.

Methods

In this case-control study, a total of 7134 participants, including 4335 moderate-to-severe OSA diagnosed by standard polysomnography and 2799 community-based controls were enrolled. Anthropometric and biochemical data were collected. Mendelian randomization (MR) analyses were performed using the genetic risk score, based on 29 body mass index (BMI)- and 11 waist-hip-ratio (WHR)-associated single nucleotide polymorphisms as instrumental variables. The causal associations of these genetic scores with OSA and its quantitative phenotypes were analyzed.

Results

Obesity was strongly correlated with OSA in observational analysis (β= 0.055, P = 3.7 × 10-5). In MR analysis, each increase by one standard deviation in BMI was associated with increased OSA risk [odds ratio (OR): 2.21, 95% confidence interval (CI): 1.62-3.02, P = 5.57 × 10-7] and with 2.72-, 4.68-, and 3.25-fold increases in AHI, ODI, and MAI, respectively (all P < 0.05) in men. However, no causal associations were found between WHR and OSA risk or OSA quantitative traits in men and women.

Conclusion

Compared to abdominal obesity, overall obesity showed a causal relationship with OSA and its quantitative traits, especially in men.

Disturbed sleep is associated with reduced verbal episodic memory and entorhinal cortex volume in younger middle-aged women with risk-reducing early ovarian removal

Introduction

Women with early ovarian removal (<48 years) have an elevated risk for both late-life Alzheimer's disease (AD) and insomnia, a modifiable risk factor. In early midlife, they also show reduced verbal episodic memory and hippocampal volume. Whether these reductions correlate with a sleep phenotype consistent with insomnia risk remains unexplored.

Methods

We recruited thirty-one younger middleaged women with risk-reducing early bilateral salpingo-oophorectomy (BSO), fifteen of whom were taking estradiol-based hormone replacement therapy (BSO+ERT) and sixteen who were not (BSO). Fourteen age-matched premenopausal (AMC) and seventeen spontaneously peri-postmenopausal (SM) women who were ~10y older and not taking ERT were also enrolled. Overnight polysomnography recordings were collected at participants' home across multiple nights (M=2.38 SEM=0.19), along with subjective sleep quality and hot flash ratings. In addition to group comparisons on sleep measures, associations with verbal episodic memory and medial temporal lobe volume were assessed.

Results

Increased sleep latency and decreased sleep efficiency were observed on polysomnography recordings of those not taking ERT, consistent with insomnia symptoms. This phenotype was also observed in the older women in SM, implicating ovarian hormone loss. Further, sleep latency was associated with more forgetting on the paragraph recall task, previously shown to be altered in women with early BSO. Both increased sleep latency and reduced sleep efficiency were associated with smaller anterolateral entorhinal cortex volume.

Discussion

Together, these findings confirm an association between ovarian hormone loss and insomnia symptoms, and importantly, identify an younger onset age in women with early ovarian removal, which may contribute to poorer cognitive and brain outcomes in these women.

Sleep dysfunction mediates the relationship between hypothalamic-insula connectivity and anxiety-depression symptom severity bidirectionally in young adults

BACKGROUND

The hypothalamus plays a crucial role in regulating sleep-wake cycle and motivated behavior. Sleep disturbance is associated with impairment in cognitive and affective functions. However, how hypothalamic dysfunction may contribute to inter-related sleep, cognitive, and emotional deficits remain unclear.

METHODS

We curated the Human Connectome Project dataset and investigated how hypothalamic resting state functional connectivities (rsFC) were associated with sleep dysfunction, as evaluated by the Pittsburgh Sleep Quality Index (PSQI), cognitive performance, and subjective mood states in 687 young adults (342 women). Imaging data were processed with published routines and evaluated with a corrected threshold. We examined the inter-relationship amongst hypothalamic rsFC, PSQI score, and clinical measures with mediation analyses.

RESULTS

In whole-brain regressions with age and drinking severity as covariates, men showed higher hypothalamic rsFC with the right insula in correlation with PSQI score. No clusters were identified in women at the same threshold. Both hypothalamic-insula rsFC and PSQI score were significantly correlated with anxiety and depression scores in men. Further, mediation analyses showed that PSQI score mediated the relationship between hypothalamic-insula rsFC and anxiety/depression symptom severity bidirectionally in men.

CONCLUSIONS

Sleep dysfunction is associated with negative emotions and hypothalamic rsFC with the right insula, a core structure of the interoceptive circuits. Notably, anxiety-depression symptom severity and altered hypothalamic-insula rsFC are related bidirectionally by poor sleep quality. These findings are specific to men, suggesting potential sex differences in the neural circuits regulating sleep and emotional states that need to be further investigated.

Mild Traumatic Brain Injury Affects Orexin/Hypocretin Physiology Differently in Male and Female Mice

Traumatic brain injury (TBI) is known to affect the physiology of neural circuits in several brain regions, which can contribute to behavioral changes after injury. Disordered sleep is a behavior that is often seen after TBI, but there is little research into how injury affects the circuitry that contributes to disrupted sleep regulation. Orexin/hypocretin neurons (hereafter referred to as orexin neurons) located in the lateral hypothalamus normally stabilize wakefulness in healthy animals and have been suggested as a source of dysregulated sleep behavior. Despite this, few studies have examined how TBI affects orexin neuron circuitry. Further, almost no animal studies of orexin neurons after TBI have included female animals. Here, we address these gaps by studying changes to orexin physiology using ex vivo acute brain slices and whole-cell patch clamp recording. We hypothesized that orexin neurons would have reduced afferent excitatory activity after injury. Ultimately, this hypothesis was supported but there were additional physiological changes that occurred that we did not originally hypothesize. We studied physiological properties in orexin neurons approximately 1 week after mild traumatic brain injury (mTBI) in 6-8-week-old male and female mice. mTBI was performed with a lateral fluid percussion injury between 1.4 and 1.6 atmospheres. Mild TBI increased the size of action potential afterhyperpolarization in orexin neurons from female mice, but not male mice and reduced the action potential threshold in male mice, but not in female mice. Mild TBI reduced afferent excitatory activity and increased afferent inhibitory activity onto orexin neurons. Alterations in afferent excitatory activity occurred in different parameters in male and female animals. The increased afferent inhibitory activity after injury is more pronounced in recordings from female animals. Our results indicate that mTBI changes the physiology of orexin neuron circuitry and that these changes are not the same in male and female animals.

Effect of sleep report feedback using information and communication technology combined with health guidance on improving sleep indicators in community-dwelling older people: a pilot trial

BACKGROUND

This study evaluated the preliminary effect of an integrated novel intervention comprising visualised sleep report feedback using information and communication technology and periodic health guidance on improving sleep indicators among community-dwelling older people.

METHODS

The intervention was implemented among 29 older people in Sakai City, Japan, in a 3 months pilot trial. Non-worn actigraph devices were placed under participants' bedding to continuously measure their sleep state, and they received monthly sleep reports in writing. Sleep efficiency, total sleep time, sleep latency, and the number of times away from bed were recorded. A trained nurse expertly interpreted participants' sleep data and provided telephone health guidance. The first month's data were used as the baseline (T1), the second month provided data for the first intervention (T2), and the third month provided data for the second intervention (T3). Friedman tests and Wilcoxon signed-rank tests were used to examine differences in sleep outcomes between different time points.

RESULTS

Participants' mean age was 78.97 ± 5.15 years, and 51.72% (15/29) were female. Comparison of T2 and T1 showed the intervention decreased participants' sleep latency at T2 (P = 0.038). Compared with T1, the intervention significantly decreased sleep latency (P = 0.004), increased total sleep time (P < 0.001), and improved sleep efficiency (P < 0.001) at T3. When T3 was compared with T2, only total sleep time was significantly increased (P < 0.001). There were no significant differences in the number of times away from bed across the three time points (P > 0.05).

CONCLUSIONS

This visualised sleep report feedback and periodic health guidance intervention for community-dwelling older people showed promising, albeit small preliminary effects on sleep. A fully powered randomised controlled trial is required to verify the significance of this effect.

Factors influencing recurrence after an ischemic stroke vary by sex

OBJECTIVES

To determine the factors that affect recurrent stroke after acute ischemic stroke, specifically between male and female groups.

METHODS

We examined relative factors associated with recurrent stroke in Chinese patients with first-ever ischemic stroke. LASSO (least absolute shrinkage and selection operator) Cox regression were used to determine the predictors of recurrent stroke in the male and female groups. Next, We used Kaplan-Meier survival curves and interactions among these predictors to assess the association between relapse-related factors and recurrent stroke.

RESULTS

During one year of follow-up, we documented 42 incidents of recurrent stroke in males and 15 in females. There was no significant difference in the overall recurrence rate between men and women. We finally identified three variables in males and one variable in females associated considerably with recurrent stroke by LASSO Cox regression. In females, good sleep appeared to be the most significant protective factor against recurrent stroke(hazard ratio [HR], 0.21; 95% CI, 0.08-0.57). In the male group, we found two risk factors: atherosclerotic burden (HR, 2.42; 95% CI, 1.30-4.51) and coronary heart disease (HR, 2.98; 95% CI, 1.16-7.66); and one protective factor: domestic/physical activities (HR, 0.45; 95% CI, 0.24-0.83). We also found an interaction between good sleep and domestic/physical activities in males (Pinteraction = 0.016).

DISCUSSION

Our data indicate that the factors for recurrent stroke may differ by sex. Engaging in domestic/physical activities may substantially lower recurrent strokes in Chinese adult males. And good sleep in females appears to be more important in preventing stroke recurrence.

Comparing Perceived Sleep Quality, Practices, and Behaviors of Male and Female Elite Rugby Union Athletes with the Use of Sleep Questionnaires

Objective  To evaluate the differences in subjective sleep quality, quantity, and behaviors among male and female elite rugby union athletes through two common sleep questionnaires. Materials and Methods  A sample of 38 male and 27 female elite rugby union athletes filled out the Athlete Sleep Behavior Questionnaire (ASBQ) and the Pittsburgh Sleep Quality Index (PSQI). Global scores and individual items for each questionnaire were compared to assess differences between sexes. Results  Male athletes reported significantly longer sleep duration (7 h 50 m ± 50 m versus 7h 12 m ± 58 m respectively; p ≤ 0.01; d  = 0.70) and higher habitual sleep efficiency (88% versus 83% respectively; p  < 0.05; d  = 0.54) when compared with female athletes. Individual items of the ASBQ revealed significant differences between male and female athletes for five questions. Male athletes displayed higher instances of taking stimulants before training or competition and consuming alcohol within 4 hours of going to bed. Conversely, female athletes expressed greater thought or worry while in bed and a higher instance of training late at night. Discussion  Male athletes displayed better self-reported sleep quality and quantity than female athletes; however, the present study highlighted that male and female elite rugby union athletes face specific challenges that differ. It appears that the differences observed between male and female elite rugby union athletes may be due to differing levels of professionalism or differences in training or competition schedules.

Low mindfulness is related to poor sleep quality from middle adolescents to emerging adults: a process model involving resilience and emotional dysfunction

OBJECTIVES

Transitions from middle adolescence into merging adulthood, a life stage between age 15-25, has a high prevalence of sleep problems. Mindfulness is a trait defined as being attentive to the present moment which positively relates to sleep quality. In this study, we aimed to investigate how resilience and emotional dysfunction may influence the relationship between trait mindfulness and sleep quality.

METHODS

The Five Facet Mindfulness Questionnaire, Connor-Davidson Resilience Scale, Pittsburgh Sleep Quality Index and Depression Anxiety Stress Scales were used to measure the key variables through an online survey of 497 participants between middle adolescence and emerging adults (317 females, mean age 18.27 ± 0.76 years). A process model was built to investigate the mediating roles of resilience and emotional dysfunction in the impact of trait mindfulness on sleep quality, together with the relationships between their specific components.

RESULTS

We found a positive association between mindfulness and sleep quality through resilience and through emotional dysfunction, and through the sequential pathway from resilience to emotional dysfunction. Of note, acting with awareness (mindfulness facet) showed significant indirect effects on sleep quality, mediated by resilience and emotional dysfunction.

CONCLUSIONS

Our findings may unveil the underlying mechanisms of how low mindfulness induces poor sleep quality. The findings indicate that conceiving mindfulness as a multifaceted construct facilitates comprehension of its components, relationships with other variables, and underscores its potential clinical significance given its critical implications for mental health.

The relationship of daily physical activity and sleep in adults: variations by age, sex, and race

Prior work suggests physical activity (PA) is related to quantity and quality of sleep. Questions remain regarding directionality, and whether relationships vary by age, sex, and race. We examined daily bidirectional associations between PA and sleep over one week. Participants were 427 adults from the MIDUS Biomarker study, with a mean age of 54.21 ± 11.67 (61% female, 30% non-white). PA (total activity) and sleep (total sleep time; TST and waking after sleep onset; WASO) were measured with an ActiWatch 64. Multilevel mixed-effects models showed differences in the relationships between PA and sleep by age, race, and sex. Following a day with increased PA, younger and nonwhite participants had significantly shorter TST. Days with higher PA were also associated with less WASO for younger participants. Bidirectional effects also emerged; following a night with shorter TST, men, not women, engaged in less next-day PA. Like other studies of daily PA and sleep, effect sizes were small. Future studies should assess potential mechanisms that could explain these demographic differences.

Is exposure to chemical pollutants associated with sleep outcomes? A systematic review

Environmental exposures may influence sleep; however, the contributions of environmental chemical pollutants to sleep health have not been systematically investigated. We conducted a systematic review to identify, evaluate, summarize, and synthesize the existing evidence between chemical pollutants (air pollution, exposures related to the Gulf War and other conflicts, endocrine disruptors, metals, pesticides, solvents) and dimensions of sleep health (architecture, duration, quality, timing) and disorders (sleeping pill use, insomnia, sleep-disordered breathing)). Of the 204 included studies, results were mixed; however, the synthesized evidence suggested associations between particulate matter, exposures related to the Gulf War, dioxin and dioxin-like compounds, and pesticide exposure with worse sleep quality; exposures related to the Gulf War, aluminum, and mercury with insomnia and impaired sleep maintenance; and associations between tobacco smoke exposure with insomnia and sleep-disordered breathing, particularly in pediatric populations. Possible mechanisms relate to cholinergic signaling, neurotransmission, and inflammation. Chemical pollutants are likely key determinants of sleep health and disorders. Future studies should aim to evaluate environmental exposures on sleep across the lifespan, with a particular focus on developmental windows and biological mechanisms, as well as in historically marginalized or excluded populations.

Subjective Sleep Quality Versus Objective Accelerometric Measures of Sleep and Systemic Concentrations of Sleep-Related Hormones as Objective Biomarkers in Fibromyalgia Patients

Poor quality of sleep leads to an increase in severity of the symptoms associated with fibromyalgia (FM) syndrome and vice versa. The aim of this study was to determine if the poor perceived sleep quality in FM patients could be corroborated by objective physiological determinations. Perceived sleep quality was evaluated (through the Pittsburgh Sleep Quality Index) in 68 FM patients compared to an age-matched reference group of 68 women without FM. Objective sleep quality (measured using accelerometry), and systemic concentrations of sleep-related hormones (catecholamines, oxytocin, serotonin, and melatonin) were evaluated in two representative groups from the reference control group (n = 11) and FM patients (n = 11). FM patients reported poorer subjective sleep quality compared to the reference group. However, no significant differences were found in accelerometry parameters, except for a delay in getting in and out of bed. In addition, FM patients showed no significant differences in oxytocin concentration and adrenaline/noradrenaline ratio, as well as a lower serotonin/melatonin ratio. Poor perception of sleep quality in FM patients does not correspond to objective determinations. A dysregulation of the stress response could be associated with the delay in their resting circadian rhythm and difficulty falling asleep. This would be the cause that justifies the perceived lack of rest and the fatigue they feel when waking up.

Sex- and age-specific effects on the development of addiction and compulsive-like drinking in rats

BACKGROUND

Biological factors are known to influence disease trajectories and treatment effectiveness in alcohol addiction and preclinical and clinical evidence suggests that sex is an important factor influencing disease dynamics in alcohol dependence. Another critical factor is age at first intoxicating drink, which has been identified as a risk factor for later alcohol binging. Preclinical research allows prospective monitoring of rodents throughout the lifespan, providing very detailed information that cannot be acquired in humans. Lifetime monitoring in rodents can be conducted under highly controlled conditions, during which one can systematically introduce multiple biological and environmental factors that impact behaviors of interest.

METHODS

Here, we used the alcohol deprivation effect (ADE) rat model of alcohol addiction in a computerized drinkometer system, acquiring high-resolution data to study changes over the course of addictive behavior as well as compulsive-like drinking in cohorts of adolescent vs. adult as well as male vs. female rats.

RESULTS

Female rats drank more alcohol than male rats during the whole experiment, drinking much more weak alcohol (5%) and similar amounts of stronger alcohol solutions (10%, 20%); female rats also consumed more alcohol than male rats during quinine taste adulteration. Increased consumption in females compared to males was driven by larger access sizes of alcohol. Differences in circadian patterns of movement were observed between groups. Early age of onset of drinking (postnatal day 40) in male rats had surprisingly little impact on the development of drinking behavior and compulsivity (quinine taste adulteration) when compared to rats that started drinking during early adulthood (postnatal day 72).

CONCLUSIONS

Our results suggest that there are sex-specific drinking patterns, not only in terms of total amount consumed, but specifically in terms of solution preference and access size. These findings provide a better understanding of sex and age factors involved in the development of drinking behavior, and can inform the preclinical development of models of addiction, drug development and exploration of options for new treatments.

The effects of hormonal contraceptive use on sleep in women: A systematic review and meta-analysis

Hormonal contraceptives are some of the most widely used medications worldwide, but studies on their effects on sleep are contradictory, with some reporting a sleep-promoting effect, while others a sleep-inhibiting effect. Our objective was, therefore, to undertake a systematic review and meta-analysis of the literature on this subject to try to clarify their effects. A search was conducted in three databases (PubMed, Scopus and Web of Science). Only studies evaluating hormonal contraception use were considered eligible, and both objective and subjective sleep-related outcomes were considered. Individual effect size was calculated for each article, and meta-analyses were performed using a DerSimonian and Laird random effects method. The initial search identified 2076 articles, of which 13 met the criteria for the study after full text evaluation. A total of 33 meta-analyses were performed, three of them related to subjective measures and 30 considering data from polysomnography. The only statistically significant result between contraceptive users and non-contraceptive users was observed in respect of wake after sleep onset, which was 7 min shorter among contraceptive users (-7.12 [-12.80; -1.44]; I²  = 65%; p = 0.01). In conclusion, hormonal contraceptives are not associated with clinically relevant changes in sleep patterns in women.

The stress of losing sleep: Sex-specific neurobiological outcomes

Sleep is a vital and evolutionarily conserved process, critical to daily functioning and homeostatic balance. Losing sleep is inherently stressful and leads to numerous detrimental physiological outcomes. Despite sleep disturbances affecting everyone, women and female rodents are often excluded or underrepresented in clinical and pre-clinical studies. Advancing our understanding of the role of biological sex in the responses to sleep loss stands to greatly improve our ability to understand and treat health consequences of insufficient sleep. As such, this review discusses sex differences in response to sleep deprivation, with a focus on the sympathetic nervous system stress response and activation of the hypothalamic-pituitary-adrenal (HPA) axis. We review sex differences in several stress-related consequences of sleep loss, including inflammation, learning and memory deficits, and mood related changes. Focusing on women's health, we discuss the effects of sleep deprivation during the peripartum period. In closing, we present neurobiological mechanisms, including the contribution of sex hormones, orexins, circadian timing systems, and astrocytic neuromodulation, that may underlie potential sex differences in sleep deprivation responses.