Disturbed sleep is a common feature after exposure to a traumatic event, especially when PTSD develops. However, although there is evidence suggesting a potential role of sleep disturbance in the progression of PTSD symptoms, the interrelationship between sleep and PTSD symptoms has yet to be determined. In order to address this knowledge gap, we have investigated the influence of initial sleep characteristics on the evolution of post-traumatic stress disorder (PTSD) symptoms over 4 years of follow-up among individuals exposed to the Brazilian Kiss nightclub fire. Participants were individuals exposed to the 2013 Kiss nightclub fire in Brazil. Sleep characteristics and PTSD symptoms were measured within the 4 years following the fire by self-report questionnaires, such as The Pittsburgh Sleep Quality Index (PSQI), and PTSD Checklist - Civilian version (PCL-C). Generalized estimating equations (GEE) models were used to examine the longitudinal associations (by estimating the relative effects of initial sleep problems on PTSD symptoms after adjusting for covariates). Comprehensive information concerning socio-demographic factors, health status, and sleep complaints were obtained. A total of 232 individuals were included. In GEE models, no significant interactions were observed between sociodemographic variables and PTSD symptoms in the follow-up period, however, associations were found between PTSD at baseline and the following factors: the female gender, the victim individuals and the existence of prior psychiatric disease. Initial subjective sleep parameters were strongly associated with PTSD symptoms over 4 years, mainly the presence of disturbed dreams (p = 0.012), increased sleep latency (p = 0.029), and reduced sleep duration (p = 0.012). Sleep complaints and PTSD symptoms were common among individuals after the disaster. The current study has found that the presence of sleep complaints, especially increased sleep latency, presence of disturbed dreams and short sleep duration, in the initial presentation after the fire was consistently associated with the perpetration of PTSD symptoms in the next 4 years of follow-up. These findings suggest that interventions addressing these sleep complaints have the potential to reduce the persistence and/or severity of PTSD symptoms.

Sleep quality, key to physical and mental health, requires regular assessment in clinical and non-clinical settings. Despite widespread use, the dimensionality of the Pittsburgh Sleep Quality Index (PSQI) is debated, and its Hindi version\'s factor structure remains unexplored. Our study evaluates the PSQI\'s dimensionality among Indian adolescents and adults aiming to demonstrate cross-language (Hindi and English) invariance of its factor structure. The PSQI showed satisfactory item reliability, and a best-fitting two-factor model: \"sleep efficiency\" (comprising sleep duration and habitual sleep efficiency), and \"perceived sleep quality\" (comprising remaining five PSQI components). This model showed configural invariance across age groups, sexes, and languages. Metric invariance was noted across age groups, but a partial metric non-invariance was observed across languages and sexes as reflected by differences in factor loadings. The second-order factor structure model had an excellent fit indicating the usefulness of aggregate scores of the two factors as a single index of sleep quality. Our findings better support a two-factor structure of sleep quality (both for English and Hindi versions of PSQI) in India. However, further validation in diverse clinical and non-clinical samples is warranted.

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.

BACKGROUND: Healthy sleep is vital for maintaining optimal mental and physical health. Accumulating evidence suggests that sleep loss and disturbances play a significant role in the biological aging process, early onset of disease, and reduced lifespan. While numerous studies have explored the association between biological aging and its drivers, only a few studies have examined its relationship with sleep quality. In this study, we investigated the associations between sleep quality and epigenetic age acceleration using whole blood samples from a cohort of 692 Korean adults. Sleep quality of each participant was assessed using the validated Pittsburgh Sleep Quality Index (PSQI), which encompassed seven domains: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbance, use of sleep medication, and daytime dysfunction. Four epigenetic age accelerations (HorvathAgeAccel, HannumAgeAccel, PhenoAgeAccel, and GrimAgeAccel) and the pace of aging, DunedinPACE, were investigated for epigenetic aging estimates.
RESULTS: Among the 692 participants (good sleepers [n = 441, 63.7%]; poor sleepers [n = 251, 36.3%]), DunedinPACE was positively correlated with PSQI scores in poor sleepers ( γ =0.18, p < 0.01). GrimAgeAccel ( β =0.18, p = 0.02) and DunedinPACE ( β =0.01, p < 0.01) showed a statistically significant association with PSQI scores only in poor sleepers by multiple linear regression. In addition, every one-point increase in PSQI was associated with a 15% increase in the risk of metabolic syndrome (MetS) among poor sleepers (OR = 1.15, 95% CI = 1.03-1.29, p = 0.011). In MetS components, a positive correlation was observed between PSQI score and fasting glucose ( γ = 0.19, p < 0.01).
CONCLUSIONS: This study suggests that worsening sleep quality, especially in poor sleepers, is associated with accelerated epigenetic aging for GrimAgeAccel and DundinePACE with risk of metabolic syndrome. This finding could potentially serve as a promising strategy for preventing age-related diseases in the future.

UNASSIGNED: This study aimed to assess the structural validity of the Chinese version of the Pittsburgh Sleep Quality Index (PSQI) among Chinese professional athletes and examine its test-retest reliability and convergent validity across different timeframes.
UNASSIGNED: 581 Chinese professional athletes participated. Exploratory and confirmatory factor analyses were conducted on the Chinese version of the PSQI. Test-retest reliability was assessed over 2 weeks, 1 week, and 2-3 days within a 1-month timeframe. Additional reliability analysis over a 2-day interval was conducted within a 1-week timeframe. Convergent validity was assessed using Chinese versions of the Insomnia Severity Index (ISI), the Athlete Sleep Screening Questionnaire (ASSQ), and actigraphy. A 1-month tracking was conducted, with weekly completion of the PSQI using a one-week timeframe, supplemented by assessments in the second and fourth week using two-week and one-month timeframes. Relationships between weekly results and those over two weeks and one month examined, along with convergent validity, using sleep diary and actigraphy.
UNASSIGNED: The PSQI exhibited a two-factor structure (sleep quality and sleep efficiency), with good model fit (CFI = 0.960, AGFI = 0.924, TLI = 0.925, RMSEA = 0.085). Test-retest reliability was satisfactory for intervals of one week or more (r = 0.721 ~ 0.753). Using a one-week timeframe, the total score and two dimensions exhibited good reliability (r = 0.769 ~ 0.881), but only the total score and sleep quality showed high correlations with ISI and ASSQ (r = 0.701 ~ 0.839). Throughout the tracking, monthly responses correlated well with the most recent weeks (r = 0.732 ~ 0.866).
UNASSIGNED: The PSQI demonstrates a two-factor structure in Chinese athletes, with sleep quality being predominant. Test-retest reliability within a one-month timeframe is unstable, suggesting a one-week timeframe performs better. Distinguishing between the two dimensions, employing shorter timeframes, and incorporating objective measures are recommended.

UNASSIGNED: Sleep problems are common and impactful among individuals with Rett syndrome (RTT) and their caregivers. We examined the sleep patterns of 29 RTT patients and their primary caregivers using various assessment tools. The study found that a majority of the patients experienced sleep disturbances, with younger patients showing more sleep difficulties. Caregivers also reported poor sleep quality. The findings emphasize the need to address sleep problems in RTT management, as improving sleep quality can positively impact the well-being of individuals with RTT and their caregivers.

UNASSIGNED: Thyroid problems and sleep disturbances are common health problems that impact people of all ages, income levels, and genders. The clinical relationship between these conditions is still not well understood, despite their widespread occurrence. The main objectives of the study were to determine the prevalence of thyroid disorders and evaluate the relationship between them and sleep quality in the Saudi Arabian population.
UNASSIGNED: The study employed an observational cross-sectional design and included a representative Saudi Arabian cohort. The Pittsburgh Sleep Quality Index (PSQI) was included in a digital self-administered survey that participants were asked to complete.
UNASSIGNED: There were 1044 responders in the study, most of whom (54%) were between the ages of 21 and 30. Female respondents made up 62% of the sample. Thyroid disorders were diagnosed in 9.2% of cases. A significant correlation was found (p=0.001 and p<0.001, respectively) between thyroid disorders and sleep disturbances as well as the use of sleep medications.
UNASSIGNED: The study revealed a significant prevalence of poor sleep quality in the Saudi population as a whole, with thyroid disorder diagnosis and female gender emerging as independent risk factors. More extensive longitudinal studies in the area are desperately needed.

BACKGROUND: There is growing evidence of the benefit of physical activity and mindfulness in breast cancer patients (HC et al. in BMC Complement Altern Med, 2017). Yoga offers a combination of both. The aim of this study was to establish an online yoga program for breast cancer patients and survivors. As the project was launched during the (COVID) pandemic restrictions, we intended to prove effective online yoga as a way to access supportive therapy independently of sanitary issues and geographic locations in rural regions.
METHODS: The two main outcomes were quality of life and sleep quality, and both were evaluated by standardized questionnaires (EORTC-QLQ 30 BR 23 and PSQI). Participants (n = 173) had breast cancer or a history of breast cancer and were randomized to either 6 weeks online yoga, twice a week for 45 min or a waiting control group.
RESULTS: Our results show improved sleep quality in the PSQI score and improved subitems (dyspnea and physical activity) in the EORTC quality of life score.
CONCLUSIONS: Online yoga seems to be a valid option in supportive therapy for breast cancer patients, as it improves physical fitness, dyspnea and overall sleep quality. It is also safe and cost effective as a remote intervention.
BACKGROUND: Trial registration number and date of registration for prospectively registered trials: DRKS00029548, 07.07.2022.WHO International clinical trials registry platform number: DRKS00029548. The registration number of the ethical committee CAU in Kiel: D 589/20.

[This corrects the article DOI: 10.3389/fnut.2024.1324793.].

This study aimed to examine the effect of acute exogenous melatonin administration on salivary cortisol and alpha-amylase (sCort and sAA) as representatives of the HPA axis and the sympathetic nervous system, respectively. A single-dose prolonged-release melatonin (2 mg) or a placebo tablet was given to healthy volunteers (n = 64) at 20:00 h in a crossover design. The saliva was collected at six time points (20:00, 21:00, awakening, 30 min after awakening, 10:00, and 12:00 h) and was measured for sCort, sAA, and salivary melatonin (sMT) levels. Pulse rates and sleep parameters were also collected. Melatonin was effective in improving sleep onset latency by 7:04 min (p = .037) and increasing total sleep time by 24 min (p = .006). Participants with poor baseline sleep quality responded more strongly to melatonin than participants with normal baseline sleep quality as they reported more satisfaction in having adequate sleep (p = .017). Melatonin administration resulted in higher sCort levels at awakening time point (p = .023) and a tendency of lower sAA levels but these were not significant. Melatonin ingestion at 20:00 h resulted in a marked increase in sMT levels at 21:00 h and remained higher than baseline up to at least 10:00 h (p < .001). Melatonin increases sCort levels at certain time point with a tendency to lower sAA levels. These opposing effects of melatonin suggested a complex interplay between melatonin and these biomarkers. Also, the results confirmed the positive acute effect of a single-dose melatonin on sleep quality.