Time matters: an insight into the relationship between chrononutrition and diabetes.

Chrononutrition is a branch of chronobiology that evaluates nutrients and the pathways implicated in their regulation in accordance with circadian rhythms. Sleep deprivation and disturbances have been strongly associated with the progression of different metabolic alterations, and the time of food intake plays a fundamental role in maintaining metabolic homeostasis. It has been demonstrated that not only the components of food are important, but quantity and quality are also crucial elements of a healthy eating pattern. Chrononutrition is an emerging tool that could help improve dietary interventions beyond those derived from consuming an adequate amount of each nutrient. Diabetes is a complex endocrine pathology characterized by sustained hyperglycemia. Dietary changes are a key component in obtaining adequate control and preventing long-term complications. Recent studies emphasize the use of chrononutrition and its components as a novel dietary intervention that could improve metabolic control. The use of chrononutrition as a dietary intervention is faced with challenges such as the presence of gaps in the literature that limit its implementation. This emphasizes the imperative need for additional research that can lead to an evidence-based use of this intervention.

Association of Chrononutrition Indices with Anthropometric Parameters, Academic Performance, and Psychoemotional State of Adolescents: A Cross-Sectional Study.

Adolescents are an at-risk group for circadian misalignment. The contribution of sleep-wake rhythm instability to the psychoemotional, cognitive, and weight disorders of adolescents has been studied in sufficient detail. At the same time, there is insufficient information about the association between chrononutrition indices and the well-being of adolescents. The aim of this study is to investigate the relationship between chrononutrition indices and academic achievement, psychoemotional state, and anthropometric indicators in adolescents. The study involved 12,759 students in grades 6-11 of secondary schools, aged 14.2 ± 1.7 years old; 57.2% of whom were girls. Participants provided personal data, frequency and time of meals during the day and at night, on weekdays and weekends, and completed the Zung Self-Rating Depression Scale and the Yale Food Addiction Scale. There is a U-shaped association between eating mid-phase (EPFc), eating jetlag (EJL), and eating window (EW) with GPA, ZSDSI, and FA. At the same time, the frequency of night eating (NE) is linearly associated with the studied parameters. NE is the strongest predictor of ZSDSI (ß = 0.24), FA (ß = 0.04), and GPA (ß = -0.22). EPFc, EJL, and EW practically do not differ in the strength of their association with the studied indicators. ZSDSI is most closely associated with the chrononutrition indices. There is a weak negative association between BMI and EW (ß = -0.03) and NE (ß = -0.04). Thus, circadian eating disorders are more often observed in adolescents with poor academic performance, high levels of depression, and food addiction.

Structural validity of nursing diagnosis insomnia in older adults of a community center.

PURPOSE: Insomnia is an important sleep disorder in older persons. Conceptual analysis studies on this nursing diagnosis have been developed, but the diagnostic accuracy has not been verified. This study aimed to verify the diagnostic accuracy of the nursing diagnosis of Insomnia (00095) in older adults in a community center in Brazil. METHODS: A validation study for diagnostic accuracy of the defining characteristics of the nursing diagnosis Insomnia. Data were collected through telephone interviews with 90 participants. Latent class analysis was used to verify the sensitivity and specificity of the defining characteristics. Poisson regression was used to assess the prevalence of the association of factors related to the nursing diagnosis of insomnia. FINDINGS: A 47.42% prevalence of insomnia in the sample was identified. Defining characteristics such as expresses dissatisfaction with sleep and nonrestorative sleep-wake cycle showed the best accuracy values for insomnia, with a specificity of 0.92 (0.78-1.00) and 0.89 (0.74-1.00), respectively. Related factors such as stressors and frequent naps during the day were more likely to develop insomnia in individuals. CONCLUSIONS: This study indicates diagnostic accuracy of nursing diagnosis of insomnia in community-dwelling older people from a community center. The findings highlighted the importance of the defining characteristics of nursing diagnosis insomnia and its main related factors contributing to accurate diagnostic identification. IMPLICATIONS FOR NURSING PRACTICE: This study can contribute to providing objective clinical indicators of insomnia in the older population to guide nurses in early diagnostic confirmation for the selection of health interventions. In addition, it can be a consistent contribution to theoretical and conceptual reviews of this diagnosis.

OBJETIVO: A insônia é um importante distúrbio do sono em pessoas idosas. Foram desenvolvidos estudos de análise conceitual sobre esse diagnóstico de enfermagem, mas a precisão diagnóstica não foi verificada. Este estudo teve como objetivo verificar a acurácia diagnóstica do diagnóstico de enfermagem Insônia (00095) em idosos frequentadores de um centro de convivência no Brasil. MÉTODOS: Um estudo de validação de acurácia diagnóstica das características definidoras do diagnóstico de enfermagem Insônia. Os dados foram coletados por meio de entrevistas telefônicas com 90 participantes. Foi utilizada a Análise de Classe Latente para verificar a sensibilidade e especificidade das características definidoras. A regressão de Poisson foi usada para avaliar a prevalência da associação dos fatores relacionados ao diagnóstico de enfermagem insônia. RESULTADOS: Foi identificada uma prevalência de 47,42% de insônia na amostra. Características definidoras, como expressa insatisfação com o sono e ciclo sono-vigília não restaurador, apresentaram os melhores valores de precisão para a insônia, com especificidade de 0,92 (0,78-1,00) e 0,89 (0,74-1,00), respectivamente. Fatores relacionados, como estressores e cochilos frequentes durante o dia, aumentaram a probabilidade de desenvolver insônia em idosos do centro de convivência. CONCLUSÕES: Este estudo indica a precisão diagnóstica do diagnóstico de enfermagem de insônia em idosos que vivem em comunidade, frequentadores de um centro comunitário. Os resultados destacaram a importância das características definidoras do diagnóstico de enfermagem de insônia e seus principais fatores relacionados que contribuem para a identificação precisa do diagnóstico. IMPLICAÇÕES PARA A PRÁTICA DE ENFERMAGEM: Este estudo pode contribuir fornecendo indicadores clínicos objetivos da insônia na população idosa para orientar os enfermeiros na confirmação precoce do diagnóstico para a seleção de intervenções de saúde. Além disso, pode ser uma contribuição consistente para revisões teóricas e conceituais desse diagnóstico. DESCRITORES: Distúrbios do Início e da Manutenção do Sono; Idoso; Estudo de Validação; Diagnóstico de Enfermagem; Transtornos Cronobiológicos.

Changes in Body Temperature Patterns Are Predictive of Mortality in Septic Shock: An Observational Study.

Biological rhythms are important regulators of immune functions. In intensive care unit (ICU), sepsis is known to be associated with rhythm disruption. Our objectives were to determine factors associated with rhythm disruption of the body temperature and to assess the relationship between temperature and mortality in septic shock patients; In a cohort of septic shock, we recorded body temperature over a 24-h period on day 2 after ICU admission. For each patient, the temperature rhythmicity was assessed by defining period and amplitude, and the adjusted average (mesor) of the temperature by sinusoidal regression and cosinor analysis. Analyses were performed to assess factors associated with the three temperature parameters (period, amplitude, and mesor) and mortality. 162 septic shocks were enrolled. The multivariate analysis demonstrates that the period of temperature was associated with gender (women, coefficient -2.2 h, p = 0.031) and acetaminophen use (coefficient -4.3 h, p = 0.002). The mesor was associated with SOFA score (coefficient -0.05 °C per SOFA point, p = 0.046), procalcitonin (coefficient 0.001 °C per ng/mL, p = 0.005), and hydrocortisone use (coefficient -0.5 °C, p = 0.002). The amplitude was associated with the dialysis (coefficient -0.5 °C, p = 0.002). Mortality at day 28 was associated with lower mesor (adjusted hazard ratio 0.50, 95% CI 0.28 to 0.90; p = 0.02), and higher amplitude (adjusted hazard ratio 5.48, 95% CI 1.66 to 18.12; p = 0.005) of temperature. Many factors, such as therapeutics, influence the body temperature during septic shock. Lower mesor and higher amplitude were associated with mortality and could be considered prognostic markers in ICU. In the age of artificial intelligence, the incorporation of such data in an automated scoring alert could compete with physicians to identify high-risk patients during septic shock.

Alterations in Pregnenolone and Testosterone Levels in Male Shift Workers.

Steroid hormone levels are closely related to the endogenous circadian rhythm induced by sleep-wake and dark-light cycles. Shift work that disrupts the circadian rhythm may influence the levels of steroid hormones. The association between shift work and alterations in female sex steroid hormone levels has been studied, but little is known about testosterone and its precursor pregnenolone levels in male shift workers. The present study investigated serum pregnenolone and testosterone levels in a group of shift and daytime male workers. All participants were sampled at the beginning of the morning shift. Lower levels of serum pregnenolone and total testosterone were found in the shift workers compared to the daytime workers. Variations in pregnenolone levels may have consequences for well-being, and they might produce consequences for the levels of hormones downstream of the steroid hormone cascade, such as testosterone. The low levels of testosterone found in shift workers demonstrate the perturbative effect of shift work on testosterone serum levels, which may be independent and/or related to pregnenolone synthesis.

Delayed sleep phase disorder during the COVID-19 pandemic and its health implications.

Circadian rhythm sleep disorders are alterations that are characterized by a shift in the sleep-wake cycle relative to day and night, such as the delayed sleep phase disorder (DSPD), which is a retard of at least 2 hours in the sleep start. Typically, the patient falls asleep after 2 a.m. and wakes up after 10 a.m. and with symptom of sleep onset insomnia. The prevalence of DSPD in young adults is 0.48%, increasing to 3.3% in adolescents. Interestingly, patients with COVID-19 infection report anxiety due to the intensive care unit lockdown and constant exposure to bright light. In addition, post-COVID patients have an increased risk of developing DSPD. For example, in adolescent post-COVID patients, the prevalence of DSPD increases to 63.3%. Patients with DSPD also have alterations in metabolic health, poor school performance, cognitive impairment, and a higher risk of developing other diseases. The objective of the present review is therefore to describe the characteristics of DSPD during the COVID-19 pandemic and to outline its possible implications for physical health (eg, metabolism) and mental health (eg, anxiety or depression).

Social jetlag and risk of depression: Results from the Korea National Health and Nutrition Examination Survey.

BACKGROUND: Social jetlag, which is the mismatch between endogenous rhythm and social timing, is prevalent among the working population. Social jetlag may result in mood changes; however, evidence of relationship between social jetlag and depressive disorders has not been fully verified. Hence, this study aimed to investigate the association between social jetlag and depressive symptoms in a representative working population of South Korea. METHODS: This study included 5447 Korean employees in the Korea National Health and Nutrition Examination Survey. Social jetlag was calculated as the difference between the midpoint of sleep time on weekdays and free days. Depressive symptoms were assessed using Patient Health Questionnaire-9. Multiple logistic regression was used to estimate the odds ratio after adjusting for confounding factors. Moreover, social jetlag and continuous depression scores were evaluated using linear regression and generalized additive models. RESULTS: The proportion of the participants who had >2 h of social jetlag was 10.26 %. Depressive symptoms increased as social jetlag increased. Multiple logistic regression analysis showed that the adjusted OR (95 % confidence interval) for 1 to 2 h of social jetlag was 1.355 (0.891-2.059) and for >2 h was 1.859 (1.084-3.187), which <1 h was reference. LIMITATIONS: This study used a cross-sectional design and measurements were based on self-reported scales. CONCLUSION: This study found that social jetlag and depressive symptoms were significantly related in the Korean working population.

Common Ground between Biological Rhythms and Forensics.

Biological clocks set the timing for a large number of essential processes in the living human organism. After death, scientific evidence is required in forensic investigations in order to collect as much information as possible on the death circumstances and personal identifiers of the deceased victim. We summarize the associations between the molecular mechanisms of biological rhythms and forensically relevant aspects, including post-mortem interval and cause of death, entomological findings, sex, age, ethnicity and development. Given their importance during lifetime, biological rhythms could be potential tools to draw conclusions on the death circumstances and the identity of a deceased person by mechanistic investigations of the different biological clocks in a forensic context. This review puts the known effects of biological rhythms on the functions of the human organism in context with potential applications in forensic fields of interest, such as personal identification, entomology as well as the determination of the post-mortem interval and cause of death.

The Effect of Chronotype on Addictive Eating Behavior and BMI among University Students: A Cross-Sectional Study.

The aim of this study was to examine the effect of chronotype on addictive eating behavior and BMI in university students. A questionnaire on their sociodemographic characteristics and eating habits, as well as the three-factor eating questionnaire (TFEQ) and the morningness-eveningness questionnaire (MEQ), were given to students at Üsküdar University. Data were analyzed with IBM SPSS 26.0. This study included a total of 850 students, 46.8% of whom were male and 53.2% were female. The mean BMI was 22.94 ± 3.30 kg/m2. As the BMI values of students increased, there was a decrease of 25.6% in the TFEQ scores, regardless of gender (s = −0.256; p < 0.001), and an increase of 10.6% in their chronotype scores, meaning that the students tended to be morning types (s = 0.106; p < 0.01). A significantly negative, very weak correlation was found between the students' TFEQ and MEQ scores (s = −0.123; p < 0.001). The students' BMI (p < 0.01) and TFEQ scores (p < 0.001) were affected by their MEQ scores in a statistically significant way. It was found that each 1-point increase in the MEQ score led to a 4.0% increase in the BMI score and a 15.8% decrease in the TFEQ score. It was observed that the morning-type students tended to be obese in terms of their BMI, and these students demonstrated fewer addictive eating behaviors.

Alteraciones metabólicas y circadianas en personal de enfermería de un hospital público del noroeste de México / Circadian and metabolic alterations among nursing personnel in a northeastern public hospital in Mexico / Alterações metabólicas e circadianas na equipe de enfermagem de um hospital público no noroeste do México

RESUMEN Introducción Las alteraciones metabólicas se vinculan a los ritmos biológicos, dado que es tos sistemas controlan aspectos fisiológicos como patrones de sueño/vigilia, temperatura corporal, presión arterial y liberación de hormonas endocrinas. Objetivo Identificar la relación entre los componentes del síndrome metabólico y disincro nía circadiana en personal de enfermería de un hospital público. Métodos Estudio correlacional. Muestra censal de 30 profesionales de enfermería de dos turnos. Para la recolección de datos se utilizaron tres cédulas: a) antecedentes biosociode mográficos y laborales; b) síndrome metabólico; c) ciclo circadiano. En el procesamiento de datos se utilizó pruebas Chi-cuadrada, R de Pearson y Rho de Spearman, se verificó el su puesto de normalidad con Shapiro-Wilk. Se contó con autorización del Comité de Ética de la institución de salud y con el consentimiento informado de participantes. Resultados 43.3 % del personal de enfermería cumplió con criterios diagnósticos de síndro me metabólico, 100 % del turno nocturno presentó disincronía circadiana con base en el indicador patrón de sueño. El consumo de alcohol y nivel alto de triglicéridos, mostraron relación positiva estadísticamente significativa con la presencia de insomnio (p ≤ 0.001; p ≤ 0.05). Conclusión El síndrome metabólico es un problema de salud con alta prevalencia entre el personal de enfermería, independientemente del nivel académico o del turno laboral. El peso y los triglicéridos fueron indicadores que mostraron relación con patrones de sueño afectados. Esto enfatiza la importancia de incidir en la prevención y tratamiento del sín drome metabólico como una prioridad en el personal de enfermería, desde la salud laboral.

ABSTRACT Introduction Metabolic alterations are linked to biologic rhythms because these cycles control physiologic patterns including sleep/awake, body temperature, blood pressure, and hormones release. Objective To identify the relationship between the metabolic syndrome components and the circadian alterations among nursing personnel in a public hospital in Mexico. Method This is a correlational study. The sample was constituted of 30 nursing professio nals working in 2 shifts. Data were collected using three registers: a) bio socio-demographic and labor-related backgrounds; b) metabolic syndrome; c) circadian cycle. Chi-square, Pearson's R, Spearman's Rho, and Shapiro-Wilk normality test were calculated. The study approval was granted by the Ethics Committee of the Health Institution. The corresponding informed consent was obtained from all participants. Results 43.3 % of the nursing personnel qualified for the metabolic syndrome diagnostic criteria. 100 % of the nurses working the night shift showed circadian alterations in terms of sleep patterns. Alcohol consumption and high levels of triglycerides were positively and significantly related to insomnia (p ≤ 0.001; p ≤ 0.05). Conclusion The metabolic syndrome is a health problem with a high prevalence in all kinds of nursing personnel. Bodyweight and triglyceride levels were indicators suggesting altered sleep patterns. This situation highlights the importance of designing and implementing strategies aimed at preventing and addressing metabolic syndrome among nursing person nel as a labor health priority.

RESUMO Introdução As alterações metabólicas estão ligadas aos ritmos biológicos, pois esses siste mas controlam aspectos fisiológicos como padrões de sono/vigília, temperatura corporal, pressão arterial e liberação de hormônios endócrinos. Objetivo Identificar a relação entre os componentes da síndrome metabólica e a dissincro nia circadiana na equipe de enfermagem de um hospital público. Métodos Estudo correlacional. Amostra censitária de 30 profissionais de enfermagem com dois turnos. Para a coleta de dados foram utilizados três cartões: a) antecedentes biossociodemográficos e laborais; b) síndrome metabólica; c) ciclo circadiano. No processa mento dos dados foram utilizados os testes Qui-quadrado, R de Pearson e Rho de Spearman, a suposição de normalidade foi verificada com Shapiro-Wilk. Contou-se com a autorização do Comitê de Ética da instituição de saúde e o termo de consentimento informado dos participantes. Resultados 43.3 % da equipe de enfermagem atendeu aos critérios diagnósticos para sín drome metabólica, 100 % do plantão noturno apresentou dissincronia circadiana com base no indicador padrão de sono. O consumo de álcool e o nível elevado de triglicerídeos mos traram relação positiva estatisticamente significativa com a presença de insônia (p ≤ 0.001; p ≤ 0.05). Conclusão A síndrome metabólica é um problema de saúde de alta prevalência entre a equipe de enfermagem, independentemente do nível acadêmico ou turno de trabalho. O peso e os triglicerídeos foram indicadores que mostraram relação com os padrões de sono afetados. Isto ressalta a importância de influenciar a prevenção e o tratamento da síndrome metabólica como prioridade na equipe de enfermagem, desde a saúde do trabalhador.

Temporal distribution of emergency room visits in patients with migraine and other headaches.

Background: Headache is a leading reason for presentation to the emergency department (ED) with migraine being the most frequently headache. To ensure the adequate staffing of healthcare providers during peak times of headache visits, we analyzed the temporal distribution of emergency department visits in patients presenting with headache and/or migraine.Research design and methods: The authors conducted an ecological study, including all consecutive visits to the ED for headache. Patients were classified according to the IHS Classification. We analyzed circadian, circaseptan and circannual patterns for number of visits, comparing migraine patients with other headache patients.Results: There were 2132 ED visits for headache, including primary headache in 1367 (64.1%) cases; migraine in 963 (45.2%); secondary headache in 404 (18.9%); and unspecified headache in 366 (17.1%). The circadian pattern showed peaks around 11:00-13:00 and 17:00-19:00, with visits during the night shift 45% less frequent (p < 0.001). The circaseptan pattern showed a peak on Monday-Tuesday and a low point on Sunday (p < 0.007). The circannual pattern peaked in March and decreased in June.Conclusions: ED visits for headache showed specific circadian, circaseptan and circannual variations. No differences were found in these patterns when comparing migraine patients to other headache patients.

A Tangled Threesome: Circadian Rhythm, Body Temperature Variations, and the Immune System.

The circadian rhythm of the body temperature (CRBT) is a marker of the central biological clock that results from multiple complex biological processes. In mammals, including humans, the body temperature displays a strict circadian rhythm and has to be maintained within a narrow range to allow optimal physiological functions. There is nowadays growing evidence on the role of the temperature circadian rhythm on the expression of the molecular clock. The CRBT likely participates in the phase coordination of circadian timekeepers in peripheral tissues, thus guaranteeing the proper functioning of the immune system. The disruption of the CRBT, such as fever, has been repeatedly described in diseases and likely reflects a physiological process to activate the molecular clock and trigger the immune response. On the other hand, temperature circadian disruption has also been described as associated with disease severity and thus may mirror or contribute to immune dysfunction. The present review aims to characterize the potential implication of the temperature circadian rhythm on the immune response, from molecular pathways to diseases. The origin of CRBT and physiological changes in body temperature will be mentioned. We further review the immune biological effects of temperature rhythmicity in hosts, vectors, and pathogens. Finally, we discuss the relationship between circadian disruption of the body temperature and diseases and highlight the emerging evidence that CRBT monitoring would be an easy tool to predict outcomes and guide future studies in chronotherapy.

Exacerbation of circadian rhythms of core body temperature and sepsis in trauma patients.

PURPOSE: This study aimed to describe by mathematical modeling an accurate course of core body temperature (CBT) in severe trauma patients and its relation to sepsis. METHODS: In a cohort of severe trauma, the CBT measurements were collected for 24 h on day 2 after admission and rhythmicity assessed by Fourier transform and Cosinor analysis to describe circadian features (frequency and amplitude). CBT was compared between patients who developed sepsis or not during the early ICU stay. RESULTS: 33 patients were included in this analysis. 24 patients (73%) had a predominant rhythm of 24 h (period). The main period was lower in the 9 remaining patients (6 of 12 h, 1 of 8 h, and 2 of 6 h). Other significant frequencies of oscillation (second and third frequencies) were found, which showed an association of several well-marked rhythms. Patients with sepsis (n = 12) had a significantly higher level of CBT, but also more intense rhythms and higher amplitudes of CBT. CONCLUSION: Trauma patients exhibit complex temperature circadian rhythms. Early exacerbation of the temperature rhythmicity (in frequency and amplitude) is associated with the development of sepsis. This observation accentuates the concept of circadian disruption and sepsis in ICU patients.

Adverse effects of circadian desynchrony on the male reproductive system: an epidemiological and experimental study.

STUDY QUESTION: Is circadian desynchrony a risk factor of male reproductive damage in semen parameters and/or reproductive hormones? SUMMARY ANSWER: Circadian desynchrony correlates with decrease of sperm count, which was improved when circadian desynchrony was attenuated. WHAT IS KNOWN ALREADY: Circadian desynchrony caused by work (shift work) and non-work-related reasons is prevalent worldwide and has been found to be associated with decreased female fertility, but whether it harms male reproductive health is unclear. STUDY DESIGN, SIZE, DURATION: A hybrid research was conducted. (i) A cross-sectional study of 1346 Chinese men in 2007 was used to analyze the association between semen/hormone biomarkers and work-related circadian desynchrony, which was divided into rotating shift work and permanent shift work against non-shift work. (ii) A cohort of 796 Chinese undergraduates from 2013 to 2014 was used to analyzed the association between semen/hormone biomarkers and non-work-related circadian desynchrony (between school days and days off). (iii) The biomarker identified simultaneously in both populations was further validated in male C57BL/6J mice housed under conditions simulating circadian desynchrony. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 17 semen/hormone biomarkers were compared among rotating shift workers and permanent shift workers against non-shift workers in the 1346 reproductive-age Chinese men. A total of 14 semen/hormone biomarker was analyzed in the undergraduate cohort for correlation with non-work-related circadian desynchrony (measured by Munich Chronotype Questionnaire) in 2013 and 2014 and compared between the 2 years. Photoperiod-shifting method was used to establish the mouse model, in which the biomarker was examined and molecular mechanism was explored by apoptosis analysis, DNA content analysis, transcriptome sequencing, real-time PCR and western blotting. MAIN RESULTS AND THE ROLE OF CHANCE: Among the semen/hormone biomarkers, sperm count was found to be lower in rotating shift workers, who had a higher risk of low sperm count defined by Chinese Ministry of Health (total sperm/ejaculate < 120 × 106) than non-shift workers (odds ratio = 1.26, 95% CI 1.05-1.52). This biomarker was replicated in the undergraduate cohort, where each hour of circadian desynchrony was associated with 1.16 (95% CI 1.02-1.31) fold odds of low sperm count, and sperm count increased during 2014 in men who reduced circadian desynchrony after 2013. A decrease of sperm count with circadian desynchrony and its recovery after removal of circadian desynchrony was also observed in the mouse model. During asynchrony, increased apoptosis was found in seminiferous tubules and the marker genes of post-spermatocyte stage cells were down-regulated. The most enriched functional pathway was homologous recombination, which happened during meiosis. LIMITATIONS, REASONS FOR CAUTION: The study of human beings was observational while the animal study has potential difference in circadian desynchrony exposure and species susceptibility. Further researches are needed to clarify the causal relationship in men. WIDER IMPLICATIONS OF THE FINDINGS: These findings provide novel insight to the effect of circadian desynchrony on male reproductive health and a potential strategy for prevention of reproductive damage. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by the National Key R&D Program of China [2017YFC1002001] and National Natural Science Foundation of China [81871208]. There are no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: NA.

BRCA1 and BRCA2 Gene Expression: Diurnal Variability and Influence of Shift Work

BRCA1 and BRCA2 genes are involved in DNA double-strand break repair and related to breast cancer. Shift work is associated with biological clock alterations and with a higher risk of breast cancer. The aim of this study was to investigate the variability of expression of BRCA genes through the day in healthy subjects and to measure BRCA expression levels in shift workers. The study was approached in two ways. First, we examined diurnal variation of BRCA1 and BRCA2 genes in lymphocytes of 15 volunteers over a 24-hour period. Second, we measured the expression of these genes in lymphocytes from a group of shift and daytime workers. The change in 24-hour expression levels of BRCA1 and BRCA2 genes was statistically significant, decreasing from the peak at midday to the lowest level at midnight. Lower levels for both genes were found in shift workers compared to daytime workers. Diurnal variability of BRCA1 and BRCA2 expression suggests a relation of DNA double-strand break repair system with biological clock. Lower levels of BRCA1 and BRCA2 found in shift workers may be one of the potential factors related to the higher risk of breast cancer.

Working against the biological clock: a review for the Occupational Physician.

The master clock of the biological rhythm, located in the suprachiasmatic nucleus of the anterior hypothalamus, synchronizes the molecular biological clock found in every cell of most peripheral tissues. The human circadian rhythm is largely based on the light-dark cycle. In night shift workers, alteration of the cycle and inversion of the sleep-wake rhythm can result in disruption of the biological clock and induce adverse health effects. This paper offers an overview of the main physiological mechanisms that regulate the circadian rhythm and of the health risks that are associated with its perturbation in shift and night workers. The Occupational Physician should screen shift and night workers for clinical symptoms related to the perturbation of the biological clock and consider preventive strategies to reduce the associated health risks.

Seasonality, morningness-eveningness, and sleep in common non - communicable medical conditions and chronic diseases in a population.

The seasonal pattern for mood and behaviour, the behavioural trait of morningness-eveningness, and sleep are interconnected features, that may serve as etiological factors in the development or exacerbation of medical conditions. Methods: The study was based on a random sample of inhabitants aged 25 to 74 years living in Finland. As part of the national FINRISK 2012 study participants were invited (n=9905) and asked whether the doctor had diagnosed or treated them during the past 12 months for chronic diseases. Results: A total of 6424 participants filled in the first set of questionnaires and 5826 attended the physical health status examination, after which the second set of questionnaires were filled. Regression models were built in which each condition was explained by the seasonal, diurnal and sleep features, after controlling for a range of background factors. Of the chronic diseases, depressive disorder was associated with longer total sleep duration (p<.0001) and poor sleep quality (p<.0001). Of the measurements for health status assessment, none associated with sleep features, but systolic blood pressure yielded significant (p<.0001) associations with both seasonal and diurnal features at large. Conclusion: Sleep quality was the most sensitive probe in yielding associations with chronic diseases in this population-based study. The seasonal variations in mood and social activity, and the ease in getting up and tiredness in the morning were the most sensitive probes in yielding associations with blood pressure and waist circumference. Assessment of sleep quality, seasonal and diurnal features provides thus added value for health surveys of the general population.

The significance of circadian rhythms and dysrhythmias in critical illness.

Many physiological and cellular processes cycle with time, with the period between one peak and the next being roughly equal to 24 h. These circadian rhythms underlie 'permissive homeostasis', whereby anticipation of periods of increased energy demand or stress may enhance the function of individual cells, organ systems or whole organisms. Many physiological variables related to survival during critical illness have a circadian rhythm, including the sleep/wake cycle, haemodynamic and respiratory indices, immunity and coagulation, but their clinical significance remains underappreciated. Critically ill patients suffer from circadian dysrhythmia, manifesting overtly as sleep disturbance and delirium, but with widespread covert effects on cellular and organ function. Environmental and pharmacological strategies that ameliorate or prevent circadian dysrhythmia have demonstrated clinical benefit. Harnessing these important biological phenomena to match metabolic supply to demand and bolster cell defenses at the apposite time may be a future therapeutic strategy in the intensive care unit.

Effects of sevoflurane on expression of Egr-1 and Egr-2 in suprachiasmatic nuclei of sleep-deprived rats / 中华麻醉学杂志

Objective To evaluate the effects of sevoflurane on the expression of early growth response gene 1 (Egr-1) and Egr-2 in the suprachiasmatic nuclei (SCN) of sleep-deprived rats.Methods Forty-eight pathogen-free healthy male Sprague-Dawley rats,were divided into 4 groups (n =12 each) using a random number table:control group (group C),sleep deprivation group (group SD),sevoflurane group (group SEV) and sleep deprivation plus sevoflurane group (group SD+SEV).The rats were subjected to sleep deprivation for 96 h in group SD.The rats inhaled 2.5％ sevoflurane for 3 h in group SEV.The rats inhaled 2.5％ sevoflurane for 3 h after being subjected to sleep deprivation for 96 h in group SD+SEV.The mechanical paw withdrawal threshold (MWT) was measured at 12 h,3 days and 7 days after emergence from anesthesia (T1-3).The animals were sacrificed after blood samples were obtained from the external carotid artery,and the cerebral SCN was removed for determination of Egr-1 and Egr-2 expression by Western blot.Results Compared with group C,the MWT was significantly decreased at T1-3 in SD,SEV and SD+SEV groups,the expression of Egr-1 and Egr-2 in SCN was significantly up-regulated at T1-3 in SD and SD+SEV groups,and the expression of Egr-1 in SCN was significantly up-regulated at T1-3,and the expression of Egr-2 in SCN was up-regulated at T1 in group SEV (P＜0.05).Compared with SD and SEV groups,the MWT was significantly decreased at T1-3 in group SD+SEV,and the expression of Egr-1 and Egr-2 in SCN was significantly up-regulated at T1-3 in group SD+SEV (P＜0.05).Conclusion The mechanism by which sevoflurane aggravates hyperalgesia is related to up-regulation of Egr-1 and Egr-2 expression in SCN of sleepdeprived rats.

The relation between chronotype and treatment outcome with light therapy on a fixed time schedule.

BACKGROUND: Seasonal affective disorder (SAD) is characterized by recurrent episodes of major depression in a seasonal pattern. The therapy of choice is light therapy (LT). It is suggested that LT should be administered relative to the chronotype of the patient, with the optimal timing earlier for morning than for evening types. This study aims to retrospectively investigate the relation between chronotype and the effect of LT on a fixed time in the morning in a population of SAD patients. METHODS: Data from four different studies conducted at the University Center of Psychiatry in Groningen, the Netherlands was used. Data from 132 patients was used (103 women). Depression score was determined by a structured interview (SIGH-SAD) prior to LT and after LT. Prior to LT morningness/eveningness preference of the patient was determined by the 'Morningness/Eveningness Questionnaire' (MEQ). All patients received LT at 8:00 AM at the clinic, independent of chronotype. RESULTS: Patients had an average MEQ score of 51.5±8.2. There was no significant relationship between MEQ score and therapy success as measured with the SIGH-SAD (F2,129=0.05, ns). When patients were divided by chronotype (ranging from definite morning to moderate evening) no significant relation between MEQ score and therapy success was found (F2,129=0.02, ns). LIMITATIONS: Retrospective design. CONCLUSIONS: The lack of a significant relationship between chronotype, as measured with the MEQ, and therapy success with LT at a fixed timepoint may indicate that the anti-depressive effect of morning light in SAD patients is not explained by a phase shift of the biological clock.