The Impact of Sleep: From Ancient Rituals to Modern Challenges.

Although sleep is crucial for mental and physical health, insufficient sleep is a growing problem in our modern society. In general, adults need approximately eight hours of sleep per night, but this is often unfeasible nowadays. This sleep restriction has been observed, and it has worsened, throughout the past two centuries; therefore, it is more attributed to socioeconomic changes than to biological adaptations. The most important factors to contribute to this sleep restriction were the popularization of artificial light and industrialization. The present manuscript briefly overviews, from a socioanthropological perspective, the reasons why sleep has been impacted, disclosing its effects on individuals and on society.

Sleep staging algorithm based on smartwatch sensors for healthy and sleep apnea populations.

OBJECTIVE: Sleep stages can provide valuable insights into an individual's sleep quality. By leveraging movement and heart rate data collected by modern smartwatches, it is possible to enable the sleep staging feature and enhance users' understanding about their sleep and health conditions. METHOD: In this paper, we present and validate a recurrent neural network based model with 23 input features extracted from accelerometer and photoplethysmography sensors data for both healthy and sleep apnea populations. We designed a lightweight and fast solution to enable the prediction of sleep stages for each 30-s epoch. This solution was developed using a large dataset of 1522 night recordings collected from a highly heterogeneous population and different versions of Samsung smartwatch. RESULTS: In the classification of four sleep stages (wake, light, deep, and rapid eye movements sleep), the proposed solution achieved 71.6 % of balanced accuracy and a Cohen's kappa of 0.56 in a test set with 586 recordings. CONCLUSION: The results presented in this paper validate our proposal as a competitive wearable solution for sleep staging. Additionally, the use of a large and diverse data set contributes to the robustness of our solution, and corroborates the validation of algorithm's performance. Some additional analysis performed for healthy and sleep apnea population demonstrated that algorithm's performance has low correlation with demographic variables.

Insomnia Symptoms and Menstrual Health: Is There a Link in Women During Reproductive Phase of Life?

OBJECTIVES: To investigate the association between insomnia severity symptoms and menstrual health, fatigue and anxiety symptoms in women at reproductive age. METHOD: We used data from EPISONO (2007), an epidemiological study from the city of São Paulo, Brazil. Women completed the Insomnia Severity Index (ISI), the Chalder Fatigue Scale (CFS), and the Beck Anxiety Inventory (BAI) to obtain information about insomnia, fatigue, and anxiety symptoms. For menstrual health, we collected information using our Institutional Women's Questionnaire about menstrual flow and duration, the presence of pain during menstruation and menstrual cycle regularity. The statistical analysis was performed using ordinal logistic regression, considering p < .05. RESULTS: Of the 1,042 participants, only 282 women met the inclusion criteria to participate in this study. The mean age was 34.4 years (SD ± 8.36), and the body mass index (BMI) was 25.7 (SD ± 5.39). According to the model, a 1-unit higher CFS score increased the odds of having more insomnia symptoms in the ISI (OR = 1.170; 95% CI=[1.073; 1.279]; p < .001). In the same way, a 1-unit higher BAI score increased the chance of presenting insomnia symptoms, according to the ISI (OR = 1.072; 95% CI=[1.042; 1.104]; p < .001). The menstrual variables did not represent statistical significance in the model. CONCLUSIONS: Fatigue and anxiety symptoms were associated with insomnia symptoms; however, no association was observed between menstrual health and insomnia. The need to examine sleep when there are sleep complaints is essential to provide an accurate diagnosis that facilitates appropriate treatment and to provide better sleep quality for women.

Homocysteine as a predictor of apnea-hypopnea index in obstructive sleep apnea: a longitudinal epidemiological study (EPISONO).

BACKGROUND: Obstructive sleep apnea (OSA) affects nearly 1 billion people globally, and has established links with cardiovascular and neurocognitive complications. Although it has some limitations, the apnea-hypopnea index (AHI) is commonly used to gauge OSA severity and therapeutic response. Homocysteine (Hcy) metabolism, when impaired, can elicit cellular senescence mechanisms that may be shared with OSA. Hence, our objective was to explore the role of Hcy concentrations both as a predictor of AHI values and as a potential risk factor for OSA. METHODS: Involving 1042 volunteers aged 20 to 80 years, the initial study (2007) included polysomnographic evaluations, questionnaires on sleep and general health, as well as biochemical analyses. After an 8-year interval, 715 participants from the initial study were invited for a follow-up assessment in 2015. RESULTS: Our findings showed that Hcy was a predictor for an increased AHI, and AHI increased over time. Individuals with plasma Hcy concentrations ≥ 15 µmol/L experienced an average AHI increase of 7.43 events/hour ([beta coefficient] ß = 7.43; 95%CI 2.73 to 12.13) over time, compared to those with plasma concentrations < 10 µmol/L. A similar trend was apparent in those with plasma Hcy concentrations between 10 ≥ and < 15 µmol/L, who had an AHI increase with an average beta coefficient of 3.20 events/hour (95%CI 1.01 to 5.39) compared to those with plasma Hcy concentrations < 10 µmol/L. CONCLUSIONS: In summary, our study suggests that increased plasma Hcy concentrations could be considered a risk factor for the development of OSA. These findings highlight that elevated plasma Hcy concentrations can predict the severity of OSA, underscoring their correlation with the AHI.

Shared genetic mechanisms underlying association between sleep disturbances and depressive symptoms.

OBJECTIVES: Polygenic scores (PGS) for sleep disturbances and depressive symptoms in an epidemiological cohort were contrasted. The overlap between genes assigned to variants that compose the PGS predictions was tested to explore the shared genetic bases of sleep problems and depressive symptoms. METHODS: PGS analysis was performed on the São Paulo Epidemiologic Sleep Study (EPISONO, N = 1042), an adult epidemiological sample. A genome wide association study (GWAS) for depression grounded the PGS calculations for Beck Depression Index (BDI), while insomnia GWAS based the PGS for Insomnia Severity Index (ISI) and Pittsburg Sleep Quality Index (PSQI). Pearson's correlation was applied to contrast PGS and clinical scores. Fisher's Exact and Benjamin-Hochberg tests were used to verify the overlaps between PGS-associated genes and the pathways enriched among their intersections. RESULTS: All PGS models were significant when individuals were divided as cases or controls according to BDI (R2 = 1.2%, p = 0.00026), PSQI (R2 = 3.3%, p = 0.007) and ISI (R2 = 3.4%, p = 0.021) scales. When clinical scales were used as continuous variables, the PGS models for BDI (R2 = 1.5%, p = 0.0004) and PSQI scores (R2 = 3.3%, p = 0.0057) reached statistical significance. PSQI and BDI scores were correlated, and the same observation was applied to their PGS. Genes assigned to variants that compose the best-fit PGS predictions for sleep quality and depressive symptoms were significantly overlapped. Pathways enriched among the intersect genes are related to synapse function. CONCLUSIONS: The genetic bases of sleep quality and depressive symptoms are correlated; their implicated genes are significantly overlapped and converge on neural pathways. This data suggests that sleep complaints accompanying depressive symptoms are not secondary issues, but part of the core mental illness.

The interplay between X-chromosome functional dosage and circadian regulation in females.

PURPOSE: Biological factors and mechanisms that drive higher prevalence of insomnia in females are poorly understood. This study focused on the neurological consequences of X-chromosome functional imbalances between sexes. METHODS: Benefited from publicly available large-scale genetic, transcriptional and epigenomic data, we curated and contrasted different gene lists: (1) X-liked genes, including assignments for X-chromosome inactivation patterns and disease associations; (2) sleep-associated genes; (3) gene expression markers for the suprachiasmatic nucleus. RESULTS: We show that X-linked markers for the suprachiasmatic nucleus are significantly enriched for clinically relevant genes in the context of rare genetic syndromes and brain waves modulation. CONCLUSION: Considering female-specific patterns on brain transcriptional programs becomes essential when designing health care strategies for mental and sleep illnesses with sex bias in prevalence.

Leptin moderates the relationship between sleep quality and memory function: A population-based study.

Sleep is crucial for memory, as it promotes its encoding, consolidation, storage, and retrieval. Sleep periods following learning enhance memory consolidation. Leptin, a hormone that regulates appetite and energy balance, also influences memory and neuroplasticity. It plays a neurotrophic role in the hippocampus, enhancing synaptic function and promoting memory processes. Given these associations between sleep, memory, and leptin, this study aimed to evaluate the interplay between sleep quality, memory complaints and leptin levels. Using data from the São Paulo Epidemiologic Sleep Study (EPISONO) 2007 edition, we analyzed data from 881 participants who underwent evaluations for subjective sleep quality (Pittsburgh Sleep Quality Index), memory function (Prospective and Retrospective Memory Questionnaire), body mass index and plasmatic leptin levels. After confirming that subjects with poor sleep quality had more memory complaints in our cohort, we observed that leptin levels were increased in individuals with more memory complaints, but there was no association between leptin levels and sleep quality. Mediation analysis reinforced the direct effect of sleep quality on memory function, but leptin had no indirect effect as mediator over the sleep-memory association. Moderation analysis revealed that leptin acted as a moderator in the relationship between sleep quality and memory, with increased leptin levels enhancing the effect of sleep quality over memory function. These findings underscore the intricate interplay between sleep, memory, and metabolic factors like leptin, shedding light on potential mechanisms through which sleep influences memory and cognitive functions. Further research is needed to elucidate the exact mechanisms underlying these relationships and their implications for overall health and well-being.

Exploring the molecular pathways linking sleep phenotypes and POGZ-associated neurodevelopmental disorder.

Pogo transposable element-derived protein with ZNF domain (POGZ) gene encodes a chromatin regulator and rare variants on this gene have been associated with a broad spectrum of neurodevelopmental disorders, such as White-Sutton syndrome. Patient clinical manifestations frequently include developmental delay, autism spectrum disorder and obesity. Sleep disturbances are also commonly observed in these patients, yet the biological pathways which link sleep traits to the POGZ-associated syndrome remain unclear. We screened for sleep implications among individuals with causative POGZ variants previously described. Sleep disturbances were observed in 52% of patients, and being obese was not observed as a risk factor for sleep problems. Next, we identified genes associated with sleep-associated traits among the POGZ regulatory targets, aiming to uncover the molecular pathways that, when disrupted by POGZ loss of function, contribute to the aetiology of sleep phenotypes in these patients. The intersect between POGZ targets and sleep-related genes was used in a pathway enrichment analysis. Relevant pathways among these overlapping genes are involved in the regulation of circadian rhythm, tau protein binding, ATPase activator activity. This study may represent the beginning for novel functional investigations on shared molecular mechanisms between sleep disturbances and rare developmental syndromes related to POGZ and its regulatory targets.

How do phases of the menstrual cycle affect sleep? A polysomnographic study of the EPISONO database.

PURPOSE: Our study aimed to evaluate the impact of the menstrual cycle stages, especially menses, on sleep, inflammatory mediators, fatigue, anxiety, depression, and quality of life. METHODS: We used data from the EPISONO study cohort, selecting 96 women who had undergone one-night polysomnography. The women were distributed in three groups according to the time point of the menstrual cycle on the polysomnography night: menses, mid/late follicular phase, and luteal phase. The volunteers completed questionnaires related to sleep quality, daytime sleepiness, insomnia, fatigue, anxiety, depression, and quality of life. Blood samples were collected to analyze interleukin 6, tumor necrosis factor-alpha, and C-reactive protein. RESULTS: Sleep efficiency was statistically higher in women in the mid/late follicular group (89.9% ± 9.6) compared to menstrual (83.0% ± 10.8) and luteal (83.7% ± 12.7) groups. The mid/late follicular group presented a statistically significant reduction in sleep onset latency (7.1 ± 7.1 min) compared to the menstrual (22.3 ± 32.4 min) and luteal groups (15.9 ± 14.7 min). No statistical differences among the three groups were observed in other polysomnographic parameters, inflammatory mediators, daytime sleepiness, insomnia, fatigue, anxiety, depression, and quality of life. CONCLUSIONS: Our findings demonstrate that the mid/late follicular phase might be beneficial for women's sleep, although there were no statistically changes in inflammatory mediators among the groups.

Understanding Sexual Parasomnias: A Review of the Current Literature on Their Nature, Diagnosis, Impacts, and Management.

Sexual behavior during sleep, known as sexual parasomnias, has captured the interest of researchers and clinicians. These parasomnias involve various sexual activities that occur unconsciously during sleep. Although relatively rare, they can profoundly affect well-being and relationships and can carry legal consequences. Understanding their nature, prevalence, and causes is crucial for advancing knowledge in this field. This article revisits the topic of sexsomnia, presenting new data and discussing cases published from 2007 to 2023. By analyzing these cases, we aim to enhance recognition, diagnosis, and management of sexsomnia, reducing stigma and providing better support for affected individuals.

The impact on the quality of life and sleep complaints in a vitiligo sample and the influence of inflammatory cytokines in the interaction between vitiligo and sleep.

INTRODUCTION: Vitiligo is an autoimmune dermatosis that affects quality of life, which englobes sleep quality. Sleep regulates the immune system, including inflammatory cytokines, and other pathways, which may influence vitiligo pathogenesis. OBJECTIVES: To analyze levels of immune serum components (cytokines) in a vitiligo group, and assess whether there was any association with sleep. METHODS: This study comprised 30 vitiligo patients and 26 control individuals. Quality of life and sleep questionnaires were completed [Dermatology Life Quality Index (DLQI), Short-Form Health Survey (SF-36), Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index (ISI)]. Seven cytokines have been measured: IFN-γ, interleukin (IL)-4, IL-6, IL-10, IL-17A, IL-12 p40 and TNF-α. RESULTS: The mean age of the vitiligo group was 47.7 years-old, with prevalence of females (66.7 %). Mucosal (70 %), acral (60 %) and focal subtype (53.3 %) predominated. Signs of vitiligo activity were identified in 63.3 % of the disease sample. Total PSQI scores and scores for domain 4 (sleep efficiency) were statistically worse in vitiligo group. The SF-36 and ISI total scores were worse in the vitiligo group, although not statistically significant compared with controls. Four SF-36 domains were statistically worse in vitiligo sample, and the DLQI mean score was mild to moderate (5.57). Cytokine levels were not different between groups, or when associated with PSQI. Higher ISI scores (more severe insomnia) were related to increased IL-17A. Higher IL-4, IL-6 and IL-10 levels were associated with previous phototherapy. CONCLUSIONS: Poor sleep and impaired aspects of quality of life predominated in the vitiligo sample. Insomnia was related to IL-17A increase in vitiligo. Increased levels of IL-4, IL-6 and IL-10 were related to previous ultraviolet B narrow band (UVB-NB) phototherapy, suggesting an interaction of this treatment on immune system. Sleep disruption and the course of vitiligo may have common pathways in respect of circadian cytokines, which may represent an important subject in vitiligo management.

The relationship between irritable bowel syndrome, the gut microbiome, and obstructive sleep apnea: the role of the gut-brain axis.

Sleep disruption, especially that resulting from obstructive sleep apnea (OSA) - a widely prevalent sleep disorder - can lead to important systemic repercussions. We raise a subject of current interest, namely the possible relationship between sleep in general, OSA, and irritable bowel syndrome (IBS), an intestinal disease that can be made worse by stressful events. The intermittent hypoxia caused by OSA can induce alterations in the gut microbiota, which can lead to the dysregulation of the gut-brain axis and the worsening of IBS. This may be considered to be a circular relationship, with OSA playing a crucial role in the worsening of bowel symptoms, which in turn have a negative effect on sleep. Thus, based on previous evidence, we suggest that improving sleep quality could be a key to disrupting this relationship of IBS aggravation and OSA.

The role of upper airway and facial skeleton anatomy in the evolution of obstructive sleep apnea: an 8-year follow-up.

PURPOSE: To evaluate the role of anatomic alterations of the upper airway and facial skeleton in the evolution of obstructive sleep apnea (OSA) in a prospective population-based study with an 8-year follow-up. METHODS: This was a population-based, longitudinal, prospective study, which took place from 2007 to 2015 at the Instituto do Sono, Sao Paulo, Brazil. In 2007, type I polysomnography (PSG), otorhinolaryngological examination, and collection of anthropometric measurements of all volunteers were performed. Volunteers were classified according to their anatomical features of the upper airway and facial skeleton. After 8 years, volunteers were invited for reevaluation. The relationship between anatomical characteristics and polysomnographic evolution was evaluated. RESULTS: The study included 554 patients. After 8 years of follow-up, there was an increase in neck circumference and body mass index of the participants. There was a worsening in all polysomnographic parameters analyzed, with an increase in the apnea-hypopnea index, a decrease in minimum saturation values, and an increase in the percentage of sleep time with peripheral oxyhemoglobin saturation <90%. There was no statistical relationship between the anatomical findings considered unfavorable and the worsening of polysomnographic parameters. CONCLUSIONS: In a sample of the general population, after 8 years, we did not find any relationship between upper airway and facial skeleton characteristics and the progression of OSA.