Biological Rhythm and Chronotype: New Perspectives in Health

Associations between sleep duration, depression status, and cognitive function among Chinese elderly: A community-based study

BACKGROUND

The associations of sleep duration and depressive status on cognitive function among the elderly remain controversial. This study aimed to investigate the associative effects and mediating mechanisms between sleep duration and depressive status on cognitive function in elderly adults.

METHODS

Participants were recruited from cross-sectional and cohort surveys of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). We identified thresholds for sleep duration and depression and used logistic regression to explore their independent and joint effects on cognitive impairment. Further, we analyze the mediating effects of depressive status on the association between sleep duration and cognitive function.

RESULTS

Of 13840 elderly (median age: 84 years, female: 54.6 %), 2835 (20.5 %) had cognitive impairment. Compared with those who slept 6-8 h, the ORs (95%CIs) for those who slept < 6 h and > 8 h were 0.98 (0.85, 1.12) and 1.48 (1.32, 1.66). Compared with non-depressed, the OR (95%CI) for the depressed participants was 1.74 (1.53, 1.98). Compared with those with sleep 6-8 h and none-depression, those with sleep > 8 h and depression had the highest odds of cognitive impairment (OR = 2.40, 95%CI: 1.88-3.07). Additionally, Compared with those who slept 6-8 h, the associations between depression-mediated short and long sleep and cognitive impairment were 51.1 % and 6.5 %, respectively.

LIMITATIONS

Cross-sectional studies require caution in the interpretation of causal associations.

CONCLUSIONS

Long sleep and depression were independently and jointly associated with higher odds of cognitive impairment among the Chinese elderly, and short sleep increased the risk of cognitive impairment by promoting the prevalence of depression.

Nutraceutical composition (yeast β-glucan, prebiotics, minerals, and silymarin) predicts improvement of sleep quality and metabolic parameters: A randomized pilot study

BACKGROUND & AIMS

The search for integrative and natural therapies that favor homeostasis to boost sleep and diet quality took place for young adult populations as a non-pharmacological strategy for long-term good quality of life. Thus, the present pilot study aims to investigate the effects of 90-day consumption of a nutraceutical composition on the neuro-immune-endocrine axis, providing better sleep quality and health improvement.

METHODS

For this, from March 2021 to June 2021, twenty-two Brazilian young adult volunteers (women and men) with BMI between 18.5 and 34.9 kg/m2 were divided into three distinct supplementation groups: NSupple; NSupple plus_S, and NSupple plus. Briefly, the supplement compositions included yeast β-glucan, prebiotics, and minerals in different concentrations associated or not with the herbal medicine silymarin. Neither nutritional nor physical activity interventions were performed during this pilot study period. The anthropometrics measures, questionnaires answer data, and harvest blood for metabolic, inflammatory, and hormonal tests were collected at baseline time (day zero-T0) and day 90 (T90) post-supplementation.

RESULTS

Our results highlight that the supplementation reduced body mass index (BMI), Waist-to-height ratio (WHtR), waist circumference, AST/ALT ratio, alkaline phosphatase, and HbA1c. Post-supplementation the IL-6 and IL-10 levels and the sleep, humor, and quality of life scores were suggested to improve. Sleep quality improvement seems to predict the reduction of adiposity-related body measures.

CONCLUSION

In sum, the nutraceutical supplementation might be related to anthropometric, metabolic, and endocrine parameters after 90 days reflecting on perception of humor, sleep, and life quality enhancement. However, it is important to recognize the limitation of the data presented considering that this was a pilot study.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT04810572 registered on 20th February 2021.

Bipolar disorder is characterized by chronotype instability: A longitudinal investigation of circadian typology and mood

BACKGROUND

Chronotype is associated with circadian rhythmicity, a core etiological factor underlying bipolar disorder (BD). Given converging evidence linking late chronotype with poor mental health, the goal of the present study was to examine chronotype (in)stability and its relation to mood symptoms over time.

METHODS

Participants with BD I (n = 271), BD II (n = 88), and healthy controls (n = 217) were included (follow-upM=10 years, Range=5-15) from the Prechter Longitudinal Study. Chronotype category and midpoint of sleep, corrected for weekend sleep-debt (MSFsc), were measured with the Munich Chronotype Questionnaire administered every 12 months alongside clinician-rated mood and medication usage. Self-reported mood was measured bi-monthly. Mixed effects models tested whether mood was associated with (in)stability of chronotype category and MSFsc covarying for age, sex, age, and medication.

RESULTS

Compared to HC, individuals with BD self-reported having a later chronotype that significantly fluctuated over time. Individuals with BDI showed significantly less stability in MSFsc than HC. Anticonvulsant use was associated with more stability in MSFsc whereas antidepressant use was associated with less stability in MSFsc.

CONCLUSIONS

In a large longitudinal cohort, individuals with BD displayed significant instability in circadian typology. Psychopharmacology in BD may have differential impacts on circadian timing that is important to monitor.

Association between chronotype, social jetlag, sleep quality, and academic burnout among nursing students: A cross-sectional study

Academic burnout in nursing students is a serious problem worldwide that results in emotional exhaustion, cynicism and low professional efficacy. The aim of the current study was to examine the association between sleep quality and circadian rhythm indicators and academic burnout among Iranian nursing students. This cross-sectional study was conducted on 325 undergraduate nursing students studying at Qazvin University of Medical Sciences between November and February 2023. Data collection was carried out using self-report questionnaires including demographic characteristics, The Pittsburgh Sleep Quality Index (PSQI), reduced-Morningness-Eveningness Questionnaire (r-MEQ), and the Maslach Burnout Inventory-Student Survey (MBI-SS). Social jetlag (SJL) was defined as the absolute value of the difference between the midpoint of sleep on free days (MSF) and the midpoint of sleep on workdays (MSW). Data were analyzed using univariate and multivariate linear regression models. About 31.4% of participants had evening chronotype and almost half of them suffered from poor sleep quality. About 47.7% of the participants had SJL ≥ 2 h. In the multivariate linear regression model, students with evening chronotype compared to morning chronotype experienced more academic burnout in emotional exhaustion, cynicism and professional efficacy. PSQI score was only correlated with emotional exhaustion and cynicism subscales. Increased SJL was a predictor on all three subscales of academic burnout. The findings suggested that evening chronotype, poor sleep quality, and high SJL were associated with increased likelihood of academic burnout in nursing students. Assessment of circadian preference and sleep quality is beneficial for timely identification and prevention of academic burnout in nursing students.

High levels of anxiety and depression in women farmers from Ecuador: A cross-section study in Coastal and Highlands regions

BACKGROUND

Previous studies have shown that women farmers are particularly vulnerable to mental health disorders such as depression and anxiety.

AIMS

This study aimed to investigate the prevalence of anxiety and depression in women farmers from Ecuador Coastal and Highlands regions.

METHOD

General Anxiety Disorder‑7 (GAD‑7) and Patient Health Questionnaire‑9 (PHQ‑9) were applied. In addition, self-reported number of children, days off, hours of work, pesticide use, sleep habits and years of work in agriculture, were also collected. This cross-sectional study occurred during 2023 with 443 women, for Coastal (197) and Highlands (246), respectively. Multivariable binary logistic regression models were performed to obtained adjusted odds ratios (aOR) and their 95% confidence intervals (95% CI).

RESULTS

34.5% of Coastal women had depression, while 27.2% of Highlands women had depression. 20.3% of coastal women farmers had anxiety, while in the Highlands 24.8% had anxiety. Coastal mestizo and montubio women exhibited lower probability of depression, but this was not significant in the Highlands. Coastal women farmers that did not have children showed lower odds of depression (aOR 0.05, 95% CI [0.01, 0.34]). A lower likelihood of depression was observed in coastal women that worked more than 8 hours (aOR 0.22, 95% CI [0.07, 0.72]). Women from the Highlands that had shortened sleep duration exhibited lower odds of depression and anxiety.

CONCLUSIONS

A higher proportion of depressed women farmers was observed in the Coast region and slightly higher numbers of anxiety cases in the Highlands. The number of children may cause workload and is correlated with depression in Coastal women.

The Mixed Role of Sleep and Time of Day in Working Memory Performance of Older Adults with Mild Cognitive Impairment

The importance of night sleep for maintaining good physical and cognitive health is well documented as well as its negative changes during aging. Since Mild Cognitive Impairment (MCI) patients bear additional disturbances in their sleep, this study aimed at examining whether there are potential mixed effects of sleep and afternoon time of day (ToD) on the storage, processing, and updating components of working memory (WM) capacity in older adults with MCI. In particular, the study compared patients' performance in the three working memory components, in two-time conditions: "early in the morning and after night sleep", and "in the afternoon and after many hours since night sleep". The Working Memory Capacity & Updating Task from the R4Alz battery was administered twice to 50 older adults diagnosed with MCI. The repeated measures analysis showed statistically significant higher performance in the morning condition for the working memory updating component (p < 0.001). Based on the findings, it seems that the afternoon ToD condition negatively affects tasks with high cognitive demands such as the WM updating task in MCI patients. These findings could determine the optimal timing for cognitive rehabilitation programs for MCI patients and the necessary sleep duration when they are engaged in cognitively demanding daily activities.

The causal relationship between sleep characteristics and multi-site pain perception: a two-sample Mendelian randomization study

Objective

This Mendelian Randomization (MR) study aims to explore the potential causal relationships between four sleep traits and pain in 10 different body sites.

Materials and methods

The study utilizes exposure and outcome data from the GWAS database, employing the Inverse Variance Weighting Method (IVW) for primary causal estimates. Cochran Q and Rücker Q heterogeneity tests are conducted using IVW and MR-Egger methods, with the Egger-intercept method for pleiotropy testing, leave-one-out sensitivity analysis, and calculation of F-statistics to assess the presence of weak instrument bias.

Results

The study reveals that genetically predicted insomnia significantly increases the risk of unspecified pain, chest pain, gum pain, upper abdominal pain, and lower abdominal pain occurrence. Daytime napping is associated with a moderate reduction in the likelihood of joint pain but may concomitantly elevate the risk of chest pain, upper abdominal pain, and generalized abdominal pain. Neither sleep chronotype nor sleep duration demonstrated a definitive causal relationship with pain perception.

Conclusion

This study elucidates the causal relationships between four sleep characteristics and pain across 10 different body regions. Overall, the contribution of insomnia and sleep deficiency to pain in multiple body regions is more pronounced. Conversely, the association between adequate sleep and the likelihood of somatic pain is relatively lower and less significant.

Social Jetlag on Obesity-Related Outcomes in Spanish Adolescents: Cross-Sectional Evidence from the EHDLA Study

PURPOSE

This study aimed to investigate the association between social jetlag (SJL) and obesity-related outcomes among adolescents from Valle de Ricote (Region of Murcia, Spain). We explored the relationship between SJL and body mass index (BMI) z-score, waist circumference, and body fat percentage, as well as the odds of having excess weight, obesity, and abdominal obesity in a sample of Spanish adolescents.

METHODS

A cross-sectional study was conducted using data from the Eating Healthy and Daily Life Activities (EHDLA) project, which included 847 Spanish adolescents aged 12-17 years. SJL was assessed based on the differences in sleep patterns between weekdays and weekends. Obesity-related indicators such as BMI z-score, waist circumference, body fat percentage, excess weight, obesity, and abdominal obesity were measured. Generalized linear models with a Gaussian or binomial distribution were used to analyze the associations between SJL and obesity-related outcomes, adjusting for potential confounders.

RESULTS

The analysis revealed significant associations between SJL and BMI z-score (unstandardized beta coefficient [B] = 0.15, 95% CI: 0.05 to 0.25, p = 0.003), waist circumference (B = 1.03, 95% CI: 0.39 to 1.67, p = 0.002), and body fat percentage (B = 0.83, 95% CI: 0.31 to 1.43, p = 0.008). Additionally, the odds ratios (ORs) for excess weight (OR = 1.35, 95% CI: 1.16 to 1.57; p < 0.001), obesity (OR = 1.59, 95% CI: 1.26 to 2.00; p < 0.001), and abdominal obesity (OR = 1.46, 95% CI: 1.23 to 1.72; p < 0.001) increased significantly with each 60 min increment in SJL.

CONCLUSIONS

This study pointed out that the misalignment of sleeping times during weekdays and weekends (SJL) is significantly associated with higher BMI z-scores, waist circumference, body fat percentage, and higher odds of excess weight, obesity, and abdominal obesity among adolescents, being more significant in boys than in girls. These findings highlight the importance of addressing circadian misalignment in the prevention and management of obesity and its related metabolic disorders in this population.

Exploring the associations between chronotype, meal frequency, and physical activity: A population-based study in adults

Chronotype is an established concept designed to capture the internal clock's phase in real-life conditions. It is vital in many aspects of daily life and can interfere considerably with numerous factors in a given population. Recognizing nonmodifiable and modifiable factors is crucial for identifying covariates of interest when studying the link between chronotype and health status. To date, chronotype and its related factors have not been extensively investigated. The present study aimed to explore the association of chronotypes with meal frequency, physical activity, and demographic factors among the Saudi population. This cross-sectional web-based questionnaire involved 1369 adults (aged 18 years and above) from the general public in Saudi Arabia and was conducted between March and May 2019. Chronotype was assessed using the reduced version of the original Horne and Ostberg morningness-eveningness questionnaire (MEQ). Meal frequencies and demographics data (age, gender, marital status, place of residence, educational level, employment status, income) were obtained. Physical activity level was also obtained using the international physical activity questionnaire. The MEQ scores group individuals into three categories: morning-type, neither-type, and evening-type. The neither-type individuals represented 41.6% (95% confidence interval [CI], 37.5% - 45.6%) of the study population, followed by the morning-type (34.1%; 95% [CI], 29.8% - 38.4%), then the evening-type (24.3%, 95% [CI], 19.6% - 28.9%). Chronotype was significantly associated with age, marital status, employment status and monthly income (All p < 0.05). Significant associations between chronotype with meal frequencies (number of meals per day, breakfast frequency, lunch frequency, and dinner frequency) and physical activity were also observed (All p < 0.05). This study highlights that meal frequencies and physical activity levels are associated with chronotype distribution. Furthermore, demographics, including age, marital status, employment status, and income, were associated with chronotype distribution.

Sleep and lucid dreaming in adolescent athletes and non-athletes

During lucid dreaming (LD), dreamers are aware of experiencing a dream and may consciously influence its content. This study used an online questionnaire to investigate the LD frequency and applications in 193 adolescent athletes and non-athletes (17.40 ± 2.09 years; 46% athletes, 54% controls). Given the critical role that sleep plays in adolescent health, development, and performance, associations of LD with various sleep parameters were also explored. LD is prominent in adolescents (67.4% experienced it at least once, 30.0% once a month or more, 12.9% at least once a week), but similar in terms of frequency and uses between athletes and non-athletes. A higher proportion of those who practiced sports/dance during LD reported improved waking self-efficacy (57.1%) over sport performance (42.9%). There was no indication that chronotype preference may influence LD nor that LD may be detrimental to adolescent sleep. Athletes and controls had similar sleep durations, daytime sleepiness, and sleep disturbances frequency, but athletes reported higher sleep quality. Despite, on average, meeting the minimum sleep recommendation guidelines for their age, a relatively large proportion of adolescents did not attain sufficient sleep, particularly on weeknights (47.4% 14-17 years; 20.0% 18-21 years), suggesting that restricted sleep remains prevalent in adolescent populations.

Impact of lifestyle moderate-to-vigorous physical activity timing on glycemic control in sedentary adults with overweight/obesity and metabolic impairments

OBJECTIVE

Moderate-to-vigorous physical activity (MVPA) improves glucose levels; however, whether its timing affects daily glycemic control remains unclear. This study aims to investigate the impact of lifestyle MVPA timing on daily glycemic control in sedentary adults with overweight/obesity and metabolic impairments.

METHODS

A total of 186 adults (50% women; age, 46.8 [SD 6.2] years) with overweight/obesity (BMI, 32.9 [SD 3.5] kg/m2) and at least one metabolic impairment participated in this cross-sectional study. MVPA and glucose patterns were simultaneously monitored over a 14-day period using a triaxial accelerometer worn on the nondominant wrist and a continuous glucose-monitoring device, respectively. Each day was classified as "inactive" if no MVPA was accumulated; as "morning," "afternoon," or "evening" if >50% of the MVPA minutes for that day were accumulated between 0600 and 1200, 1200 and 1800, or 1800 and 0000 hours, respectively; or as "mixed" if none of the defined time windows accounted for >50% of the MVPA for that day.

RESULTS

Accumulating >50% of total MVPA during the evening was associated with lower 24-h (mean difference [95% CI], -1.26 mg/dL [95% CI: -2.2 to -0.4]), diurnal (-1.10 mg/dL [95% CI: -2.0 to -0.2]), and nocturnal mean glucose levels (-2.16 mg/dL [95% CI: -3.5 to -0.8]) compared with being inactive. This association was stronger in those participants with impaired glucose regulation. The pattern of these associations was similar in both men and women.

CONCLUSIONS

These findings suggest that timing of lifestyle MVPA is significant. Specifically, accumulating more MVPA during the evening appears to have a beneficial effect on glucose homeostasis in sedentary adults with overweight/obesity and metabolic impairments.

Melatonin in Human Milk: A Scoping Review

Melatonin is vital in human circadian rhythm and infant development. This scoping review summarized the current knowledge about melatonin's presence and effects in human milk to promote better understanding of its secretion pattern and clinical advancement of maternal-infant health. The review followed the Joanna Briggs Institute guideline and answered the question: What is the current knowledge about melatonin hormone in human milk? The databases searched were PubMed, CINAHL, SCOPUS, Web of Science, LILACS, Scielo, EMBASE, Science Direct, Eric, Cochrane, in addition to grey literature and reference lists of included sources. Research papers included English, Spanish, or Portuguese languages, regardless of study type or publication date. The study selection and data extraction involved two independent reviewers. Twenty-nine studies met inclusion criteria. The studies, conducted between 1993 and 2023, employed diverse designs, with cross-sectional studies being the most prevalent. Melatonin concentration exhibited a consistent pattern, being higher at night, and elevated in colostrum. The analysis methods for melatonin concentration evolved, with recent advancements contributing to more accurate measurements. Factors influencing melatonin levels, such as delivery type, maternal age, and health conditions, demonstrated a complex relationship, potentially impacting the health and development of infants. The dynamic nature of melatonin in human milk calls for continued interdisciplinary research, bridging gaps between clinical, biochemical, and epidemiological perspectives. Standardizing melatonin analysis methods are needed. Nurses should assess factors influencing melatonin levels in milk to promote interventions and guidance aimed at enhancing the regulation of the circadian cycle during the perinatal period and its benefits.

Changes in Sleep Quality, Sleep Duration, and Sickness Absence: A Longitudinal Study with Repeated Measures

BACKGROUND

Sickness absence has been linked to short and long, as well as poor, sleep in a few studies. Such studies have started from a baseline measurement and followed up on subsequent sickness absence. In the present study, however, we focused on the change in biennial reports of sickness absence and sleep measures (using work-related variables as possible modifiers). We also searched for an interaction between predictors and gender since women report more sleep problems.

METHODS

A total of 5377 individuals (random sample from the Swedish working population) participated across five biennial points of measurement. Data were analyzed using mixed-model logistic regression.

RESULTS

The multivariable analysis of variation across the five time points showed that the significant sleep-related predictors of sickness absence (at least one occurrence during the preceding year) were sleep duration during days off (OR = 1.16, 95% Cl = 1.08;1.24) and sleep problems (OR = 1.42, 95% CI = 1.33;1.51). These also remained significant after the addition of psychosocial work factors. Sensitivity analyses indicated that a 9 h sleep duration during days off may represent a critical level in terms of increased sickness absence and that late rising contributed to the association between sickness absence and long sleep duration during days off. Women reported a higher sickness absence than men (OR = 2.16, 95% CI = 1.74;2.68) and had a higher probability of sickness absence for long sleep during days off and during the workweek than men.

CONCLUSIONS

It was concluded that increases in sleep problems and sleep duration during days off are longitudinally associated with changes in sickness absence and that women have a closer link between the two. This suggests that treatment for sleep problems may reduce the risk of sickness absence.

Chronotype as a predictor of athletic performance in youth with mild intellectual disabilities

Aim

This study aimed to explore the influence of circadian rhythms on athletic performance in individuals with mild intellectual disabilities (ID), with a specific focus on elucidating the association between chronotype and various performance metrics.

Methods

The study was a cross-sectional study consisting of 30 male participants aged between 11 and 19 years and diagnosed with mild ID. The chronotypes of all participants were assessed using the Childhood Chronotype Questionnaire (CCQ). Performance assessments were divided into three groups. Group A tests [sit and reach, medicine ball throw (MBT), plank], group B tests [handgrip strength (HGS), standing long jump (SLJ), 20-m sprint (20 ms)] and group C tests [vertical jump (VJ), hanging with bent arm (HBA), Illinois agility test) in order to ensure adequate rest periods between tests and not to affect the results. These group tests were performed 48 h apart, between 09:00-10:00 and 17:00-18:00, after a dynamic warm-up session.

Results

Significant variations were observed in the sit-and-reach test (t = -4.154, d = -0.75, p < .001), HGS (t = -2.484, d = -0.45, p = .019), SLJ (t = -2.117, d = -0.38, p = .043), VJ (t = -5.004, d = -0.91, p < .001), and plank duration (t = -4.653, d = -0.84, p < .001). Evening performances showed improvement in MBT, HBA, 20 ms, and the Illinois agility test, although these differences were not statistically significant (p > .05). Notably, positive correlations were identified between participants' chronotypes and their performance in HBA (morning/evening; r = .693, p = .026; r = .656, p = .039, respectively) and the plank (evening; r = .717, p = .020), with negative correlations noted in the 20 ms (morning/evening; r = -.703, p = .023; r = -.710, p = .021, respectively).

Conclusion

The findings suggest that individuals with mild ID exhibit enhanced athletic performance during evening hours. These insights underscore the importance of considering chronotype in tailoring exercise interventions for this population to optimize outcomes.

Moderating effects of PER3 gene DNA methylation on the association between problematic mobile phone use and chronotype among Chinese young adults: Focus on gender differences

Objective

To investigate the rates of problematic mobile phone use (PMPU) and chronotypes in young adults, and examine the associations of PMPU with chronotypes, as well as its gender differences. Furthermore, we explored the moderating role of PER3 gene DNA methylation on the associations.

Methods

From April to May 2019, a total of 1,179 young adults were selected from 2 universities in Anhui and Jiangxi provinces. The Self-rating Questionnaire for Adolescent Problematic Mobile Phone Use (SQAPMPU) and reduced Morningness-Eveningness Questionnaire (rMEQ) were adopted to investigate PMPU and chronotypes in young adults, respectively. Moreover, 744 blood samples were collected to measure PER3 gene DNA methylation. Multivariate logistic regression models were established to analyze the associations between PMPU and chronotypes. Moderating analysis was used to determine whether PER3 gene DNA methylation moderated the relationships between PMPU and chronotypes.

Results

The prevalence of PMPU, morning chronotypes (M-types), neutral chronotypes (N-types), and evening chronotypes (E-types) of young adults were 24.6%, 18.4%, 71.1%, and 10.5%, respectively. Multivariate logistic regression results indicated that PMPU was positively correlated with E-types (OR = 3.53, 95%CI: 2.08-6.00), and the association was observed only in females after stratified by gender (OR = 5.36, 95%CI: 2.70-10.67). Furthermore, PER3 gene DNA methylation has a negative moderating role between PMPU and chronotypes and has a sex-based difference.

Conclusions

This study can provide valuable information for the prevention and control of circadian rhythm disturbance among young adults from the perspective of epidemiology and biological etiology.

Insomnia and short sleep duration, but not chronotype, is associated with chronic widespread pain: Mendelian randomization study

OBJECTIVES

Sleep disturbance has been associated with chronic widespread pain (CWP), but their causal relationship remains unclear. We aimed to examine the causal relationship and direction between CWP and sleep traits, namely insomnia, sleep duration and chronotype, using Mendelian Randomization.

METHOD

We used genetic association data from ~0.5 million individuals and up to 1.8 million controls from the UK Biobank (UKB). All traits were defined predominantly by self-report. Short sleep duration was defined as average ≤6 hours per 24 hours. Chronotype refers to the inclination to sleep at certain times where some wake and go to bed early ('morning' person), and others wake and go to sleep later ('evening' person). To permit use of the largest available genetic association data, we used the Causal Analysis Using Summary Effect estimates (CAUSE) method, which allows for sample overlap.

RESULTS

Insomnia (OR 1.009, 95% credible interval 1.005, 1.014; p = 0.018 that the causal model is a better fit than non-causal model) and short sleep duration (OR 1.060, 95%CrI 1.038, 1.083; p = 0.040) were causally associated with increased risk of CWP, with limited evidence for reverse causation. There was no evidence in support of long sleep duration or chronotype being associated with CWP.

CONCLUSIONS

This study suggest that insomnia and short sleep duration (≤6 hours) are associated with an increased risk of CWP. Improving short sleep duration and insomnia, rather than chronotype, may be effective in reducing the risk of CWP, although these results should be replicated in epidemiological and interventional studies.

Chronophysiology of domestic animals

This review highlights recent findings on biological rhythms and discusses their implications for the management and production of domestic animals. Biological rhythms provide temporal coordination between organs and tissues in order to anticipate environmental changes, orchestrating biochemical, physiological and behavioural processes as the right process may occur at the right time. This allows animals to adapt their internal physiological functions, such as sleep-wake cycles, body temperature, hormone secretion, food intake and regulation of physical performance to environmental stimuli that constantly change. The study and evaluation of biological rhythms of various physiological parameters allows the assessment of the welfare status of animals. Alteration of biological rhythms represents an imbalance of the state of homeostasis that can be found in different management conditions.

Thyroid Function and Sleep Patterns: A Systematic Review

Hypothyroidism, defined as a low metabolic function of the thyroid gland that results in low thyroid hormone levels, and insomnia, a condition with the inability to sleep, are two distinct conditions with little overlap that have been extensively established. Both conditions have been studied independently in terms of epidemiology, pathophysiology, diagnosis, and management. The exact causal relationship between the two conditions has yet to be elucidated, and a direct underlying pathophysiology has not been pinpointed. To gain further insight into the relationship between hypothyroidism and insomnia, we performed a systematic review to explore this relationship using predetermined guidelines. Out of 59 studies assessed, four studies evaluated the mechanisms of these two potentially comorbid conditions. Our findings suggest that hypothyroidism and insomnia may have a bidirectional relationship, with symptomatic overlap that is tied to increased metabolic comorbidities and hormonal dysregulation. These findings warrant further research to verify these early findings and gain further insight into the relationship between these conditions. A better understanding of the pathophysiology of overlap between these two conditions will help improve diagnosis and target treatment more effectively.

Influence of circadian rhythm and sleep schedules on depressive symptoms among adolescents in China

Circadian rhythm (24-hour period of physiological and behavioral changes) is the basis of the overall health, including mood and health. This study aimed to explore the influence of circadian rhythm and sleep schedules on depressive symptoms in Chinese adolescents. In this cross-sectional study, 841 middle school students were recruited and divided into two groups (depressive group, DG, n = 210, and control group, n = 631) depending on the total score of The Center for Epidemiological Studies Depression Scale for Children (CES-DC). The circadian rhythm and sleep quality among adolescents were evaluated by using the Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN) and Self-rating scale of Sleep (SRSS) scales. Furthermore, correlation analysis and logistic regression analysis were used to determine the effects of demographic factors, sleeping arrangement, sleep quality, and circadian rhythm on depressive symptoms. The DG group's CES-DC, BRIAN and SRSS scores were significantly higher than the control group's. Higher scores of BRIAN and SRSS were risk factors for depressive symptoms in Chinese adolescents. Attending a day school and waking up later on weekends may be weak protective factors. Our results suggest that circadian rhythm disturbance, sleep quality, and sleeping arrangement have a significant influence on depressive symptoms among adolescents in China.

Factors associated with the fragmentation and stability of the rest-activity rhythm in adults and older adults

This cross-sectional study aimed to identify factors related to the fragmentation and stability of the rest-activity rhythm (RAR) in adults and older adults. It is part of a larger research project investigating aspects concerning sleep duration, quality, and disorders in a representative subsample of the population. Sociodemographic data, lifestyle, health habits and subjective sleep variables were obtained; RAR records were collected by means of actigraphy and analyzed using non-parametric variables (IS, IV, M10, L5, RA, sL5, and sM10). Study participants were 313 individuals with complete actigraphy records. There was a prevalence of older adults (50.2%) and females (51.1%). Females, individuals with 4-8 y of education, and those who used alcohol abusively exhibited lower RAR fragmentation. Higher fragmentation was observed in individuals who napped and those reporting poor sleep quality. Greater rhythm stability was evident in females, older adults, those with 4-8 y of education, and those who had a partner. Smokers demonstrated lower RAR stability. These findings may contribute valuable insights for decision-making aimed at preventing and treating issues related to fragmentation and instability of the rhythm and its possible consequences to health.

Psychometric properties of the Turkish reduced morningness and eveningness questionnaire

The aim of this study was to examine the psychometric properties of the 5-item Turkish Reduced Morningness-Eveningness Questionnaire (rMEQ) for the first time. The study involved 875 university students in an adaptation and validation study. Participants completed the rMEQ, MEQ, Depression Anxiety Stress Scale-21 (DASS-21), Insomnia Severity Index (ISI), Barratt Impulsiveness Scale Short Form (BIS-SF), and Oxford Happiness Questionnaire Short Form (OHQ-SF). The factor structure, convergent validity, internal consistency, sensitivity, and specificity of the rMEQ were examined. The confirmatory factor analysis showed that the rMEQ had a one-dimensional structure with good fit indices (χ2/df = 2.94, CFI = 0.990, TLI = 0.979, RMSEA = 0.047, and SRMR = 0.019). There was a significantly strong correlation between rMEQ and MEQ. In addition, we found a significantly weak correlation between rMEQ and DASS-21, ISI, BIS-SF, and OHQ-SF. The internal consistency coefficients of rMEQ were Cronbach's α = 0.706 and McDonald's ω = 0.740. The sensitivity and specificity of rMEQ were 83.3%-92.7% for morning types and 86.3%-87.3% for evening types. The Turkish rMEQ has adequate psychometric properties and can be used to assess an individual's chronotype.

Chronotype changes after sex hormone use: A prospective cohort study in transgender users of gender-affirming hormones

Chronotype, an individual's preferred sleep-wake timing, is influenced by sex and age. Men sometimes report a later chronotype than women and older age is associated with earlier chronotype. The sex-related changes in chronotype coincide with puberty and menopause. However, the effects of sex hormones on human chronotype remain unclear. To examine the impact of 3 months of gender-affirming hormone therapy (GAHT) on chronotype in transgender persons, this study used data from 93 participants from the prospective RESTED cohort, including 49 transmasculine (TM) participants starting testosterone and 44 transfeminine (TF) participants starting estrogens and antiandrogens. Midpoint of sleep and sleep duration were measured using the ultra-short Munich ChronoType Questionnaire (µMCTQ). After 3 months of GAHT, TM participants' midpoint of sleep increased by 24 minutes (95% CI: 3 to 45), whereas TF participants' midpoint of sleep decreased by 21 minutes (95% CI: -38 to -4). Total sleep duration did not change significantly in either group. This study provides the first prospective assessment of sex hormone use and chronotype in transgender persons, showing that GAHT can change chronotype in line with cisgender sex differences. These findings provide a basis for future studies on biological mechanisms and clinical consequences of chronotype changes.

Association of genetically determined chronotype with circulating testosterone: a Mendelian randomization study

Low testosterone levels in men have been linked to decreased physical and mental function, as well as a reduced quality of life. Previous prospective observational studies have suggested an association between testosterone and sleep traits, but the causality of this relationship remains unclear. We aimed to explore the potential causal link between genetically determined sleep traits and testosterone levels in men using Mendelian randomization (MR) analysis from the UK Biobank dataset. Our exposures were genetic variants associated with sleep traits (chronotype and sleep duration), whereas our outcomes were traits of sex steroid hormones (total testosterone, TT; bioavailable testosterone, BAT; and sex hormone-binding globulin, SHBG). We employed inverse variance weighted (IVW) and weighted median (WM) methods to assess the causal associations. The IVW method offers a robust estimate of causality, whereas the WM method provides reliable results even when some genetic variants are invalid instruments. Our main analysis involving sex steroid hormones and chronotype identified 155 chronotype-related variants. The primary findings from the analysis, which used chronotype as the exposure and sex steroid hormones as the outcomes, showed that a genetically predicted chronotype score was significantly associated with an increased levels of TT (association coefficient β, 0.08; 95% confidence interval [CI], 0.02-0.14; P = 0.008) and BAT (β, 0.08; 95% CI, 0.02-0.14; P = 0.007), whereas there was no significant association with SHBG (β, 0.01; 95% CI, -0.02-0.03; P = 0.64). Meanwhile, MR analysis of sex steroid hormones and sleep duration was performed, and 69 variants associated with sleep duration were extracted. There were no significant association between sleep duration and sex steroid hormones (TT, P = 0.91; BAT, P = 0.82; and SHBG, P = 0.95). Our data support a causal association between chronotype and circulating testosterone levels in men. These findings underscore a potential causal relationship between chronotype and testosterone levels in men, suggesting that lifestyle adjustments are crucial for men's health. Recognizing factors that influence testosterone is essential. One limitation of this study is the use of one-sample MR, which can introduce potential bias due to non-independence of genetic associations for exposure and outcome. In conclusion, our findings indicate that a morning preference is correlated with circulating testosterone levels, emphasizing the potential impact of lifestyle habits on testosterone levels in men.

Social jetlag and body mass index among shift-working nurses in Korea: A cross-sectional study

PURPOSE

Shift-working nurses must function against their natural circadian system and are, thus, bound to be detrimentally affected by social jetlag. Circadian rhythms play a crucial role in regulating homeostasis, and social jetlag may increase one's risk for obesity. Therefore, this study aimed to identify associations between social jetlag and obesity among shift-working nurses.

METHODS

This cross-sectional study included 183 nurses working rotating shifts in South Korea. Chronotype and social jetlag were measured using the Morningness-Eveningness Questionnaire and the Munich Chronotype Questionnaire for Shift-Workers, respectively. Obesity was defined as a body mass index of 25.0 or higher, which was calculated using self-reported height and weight data. The associations between chronotype, social jetlag, and obesity were investigated using multiple logistic regression analysis.

FINDINGS

A total of 183 nurses were included in the analysis (81.4% women and 80.3% single, median age = 27.00 years). Majority of the participants' (95.1%) chronotypes were moderate evening or intermediate type. The mean overall social jetlag was 3 h and 31 min. The odds for obesity were 8.44 times higher among shift-working nurses whose social jetlag was over 3 h and 31 min (95% confidence interval: 1.66-42.99) while controlling for chronotype, exercise time, and eating habits.

CONCLUSIONS

Social jetlag may increase the likelihood of obesity among rotating shift-working nurses.

IMPLICATIONS FOR NURSING PRACTICE

To achieve positive outcomes for promoting nurses' health, upper nursing management should consider individual nurses' social jetlag when scheduling shifts. In addition, nursing managers should have the responsibility to educate nurses involved in shift work about the adverse effects of social jetlag.

Associations between chronotype and physical activity and well-being in adults

Circadian rhythms influence a preference for people's time of activity and sleep time during the day and the hours of best performance. The aim of the study was to assess the associations between chronotype, physical activity, and well-being in adults aged 20-50. The chronotype, physical activity and well-being scores were determined based on the Composite Scale of Morningness (CSM) questionnaire, the International Physical Activity Questionnaire (IPAQ) and the Well-Being Index (WHO-5) questionnaire, respectively. Study data consisted of the answers of 213 respondents (including 64 men) who took part in an online survey. The Spearman rank correlation coefficient and the matrix scatter plots were used to check the correlations between the CSM score and quality of life parameters' values. General linear models (GLMs) were performed to find differences in quality-of-life parameters between different combinations of sex and chronotype. Morning types showed the highest value of well-being score (mean = 13.48) while evening types the lowest one (mean = 8.35). Evening types spent the most time sitting compared to other chronotypes. Results of this study revealed the significant effect of chronotype on well-being and physical activity among adults. These findings suggest that chronotype is an important factor that psychologists and personal trainers should take into account.

Meal timing and its role in obesity and associated diseases

Meal timing emerges as a crucial factor influencing metabolic health that can be explained by the tight interaction between the endogenous circadian clock and metabolic homeostasis. Mistimed food intake, such as delayed or nighttime consumption, leads to desynchronization of the internal circadian clock and is associated with an increased risk for obesity and associated metabolic disturbances such as type 2 diabetes and cardiovascular diseases. Conversely, meal timing aligned with cellular rhythms can optimize the performance of tissues and organs. In this review, we provide an overview of the metabolic effects of meal timing and discuss the underlying mechanisms. Additionally, we explore factors influencing meal timing, including internal determinants such as chronotype and genetics, as well as external influences like social factors, cultural aspects, and work schedules. This review could contribute to defining meal-timing-based recommendations for public health initiatives and developing guidelines for effective lifestyle modifications targeting the prevention and treatment of obesity and associated metabolic diseases. Furthermore, it sheds light on crucial factors that must be considered in the design of future food timing intervention trials.

Association of the timing of evening eating with BMI Z-score and waist-to-height ratio among preschool-aged children in Finland

Later timing of eating has been associated with higher adiposity among adults and children in several studies, but not all. Moreover, studies in younger children are scarce. Hence, this study investigated the associations of the timing of evening eating with BMI Z-score and waist-to-height ratio (WHtR), and whether these associations were moderated by chronotype among 627 preschoolers (3-6-year-olds) from the cross-sectional DAGIS survey in Finland. Food intake was measured with 3-d food records, and sleep was measured with hip-worn actigraphy. Three variables were formed to describe the timing of evening eating: (1) clock time of the last eating occasion (EO); (2) time between the last EO and sleep onset; and (3) percentage of total daily energy intake (%TDEI) consumed 2 h before sleep onset or later. Chronotype was assessed as a sleep debt-corrected midpoint of sleep on the weekend (actigraphy data). The data were analysed with adjusted linear mixed effects models. After adjusting for several confounders, the last EO occurring closer to sleep onset (estimate = -0·006, 95 % CI (-0·010, -0·001)) and higher %TDEI consumed before sleep onset (estimate = 0·0004, 95 % CI (0·00003, 0·0007)) were associated with higher WHtR. No associations with BMI Z-score were found after adjustments. Clock time of the last EO was not significantly associated with the outcomes, and no interactions with chronotype emerged. The results highlight the importance of studying the timing of eating relative to sleep timing instead of only as clock time.

Chrononutrition in traditional European medicine-Ideal meal timing for cardiometabolic health promotion

Meal timing plays a crucial role for cardiometabolic health, given the circadian regulation of cardiometabolic function. However, to the best of our knowledge, no concept of meal timing exists in traditional European medicine (TEM). Therefore, in this narrative review, we aim to define the optimal time slot for energy intake and optimal energy distribution throughout the day in a context of TEM and explore further implications. By reviewing literature published between 2002 and 2022, we found that optimal timing for energy intake may be between 06:00 and 09:00, 12:00 and 14:00, and between 15:00 and 18:00, with high energy breakfast, medium energy lunch and low energy dinner and possibly further adjustments according to one's chronotype and genetics. Also, timing and distribution of energy intake may serve as a novel therapeutic strategy to optimize coction, a concept describing digestion and metabolism in TEM. Please cite this article as: Eberli NS, Colas L, Gimalac A. Chrononutrition in traditional European medicine-Ideal meal timing for cardiometabolic health promotion. J Integr Med. 2024; 22(2);115-125.

Personalized laboratory medicine in the digital health era: recent developments and future challenges

Interpretation of laboratory data is a comparative procedure and requires reliable reference data, which are mostly derived from population data but used for individuals in conventional laboratory medicine. Using population data as a "reference" for individuals has generated several problems related to diagnosing, monitoring, and treating single individuals. This issue can be resolved by using data from individuals' repeated samples, as their personal reference, thus needing that laboratory data be personalized. The modern laboratory information system (LIS) can store the results of repeated measurements from millions of individuals. These data can then be analyzed to generate a variety of personalized reference data sets for numerous comparisons. In this manuscript, we redefine the term "personalized laboratory medicine" as the practices based on individual-specific samples and data. These reflect their unique biological characteristics, encompassing omics data, clinical chemistry, endocrinology, hematology, coagulation, and within-person biological variation of all laboratory data. It also includes information about individuals' health behavior, chronotypes, and all statistical algorithms used to make precise decisions. This approach facilitates more accurate diagnosis, monitoring, and treatment of diseases for each individual. Furthermore, we explore recent advancements and future challenges of personalized laboratory medicine in the context of the digital health era.

Association of sleep traits with male fertility: a two-sample Mendelian randomization study

Background: Previous observational studies have investigated the association between sleep-related traits and male fertility; however, conclusive evidence of a causal connection is lacking. This study aimed to explore the causal relationship between sleep and male fertility using Mendelian randomisation. Methods: Eight sleep-related traits (chronotype, sleep duration, insomnia, snoring, dozing, daytime nap, oversleeping, and undersleeping) and three descriptors representing male fertility (male infertility, abnormal sperm, and bioavailable testosterone levels) were selected from published Genome-Wide Association Studies. The causal relationship between sleep-related traits and male fertility was evaluated using multiple methods, including inverse variance weighting (IVW), weighted median, Mendelian randomisation-Egger, weighted model, and simple model through two-sample Mendelian randomisation analysis. Mendelian randomisation-Egger regression was used to assess pleiotropy, Cochrane's Q test was employed to detect heterogeneity, and a leave-one-out sensitivity analysis was conducted. Results: Genetically-predicted chronotype (IVW,OR = 1.07; 95%CL = 1.04-1.12; p = 0.0002) was suggestively associated with bioavailable testosterone levels. However, using the IVW method, we found no evidence of a causal association between other sleep traits and male fertility. Conclusion: This study found that chronotype affects testosterone secretion levels. However, further studies are needed to explain this mechanism.

Chronopharmacology of diuresis via metabolic profiling and key biomarker discovery of the traditional Chinese prescription Ji-Ming-San using tandem mass spectrometry in rat models

BACKGROUND

Ji-Ming-Shan (JMS) is a traditional prescription used for patients with rheumatism, tendons swelling, relief of foot pain, athlete's foot, diuresis, gout. Although many studies have investigated the active compounds in each herb, the functional mechanism behind its therapeutic effect remains unclear.

STUDY DESIGN

Metabolic cages for sample collection. The serum components obtained from the experimental animals were analyzed using LC-MS/MS. Furthermore, cross-analysis using the software MetaboAnalyst and Venn diagrams were used to investigate chronopharmacology of JMS in the animal models.

PURPOSE

The aim of this study is to analyze the diuretic effects of JMS and to explore their chronopharmacology involved in organ regulation through four-quarter periods from serum samples of rat models.

METHODS

Metabolic cages were used for collecting the urine samples and PocketChem UA PU-4010, Fuji DRI-CHEM 800 were used to examine the urine biochemical parameters. The serum components were identified through ultra-performance liquid chromatography-quadrupole time-of-flight (UPLC-Q-TOF) with a new developed method. Cross analysis, Venn diagram, MetaboAnalyst were used to investigate the key biomarker and major metabolism route with the oral administration of the drug.

RESULT

JMS significantly changed the 6 h urine volume with no observed kidney toxicity. Urine pH value ranges from 7.0 to 7.5. The chronopharmacology of JMS diuresis activity were 0-6 and 6-12 groups. UPLC-Q-TOF analyses identified 243 metabolites which were determined in positive mode and negative mode respectively. With cross analysis in the Venn diagram, one key biomarker naringenin-7-O-glucoside has been identified. Major metabolic pathways such as 1: Glycerophospholipid metabolism, 2: Primary bile acid biosynthesis, 3: Sphingolipid metabolism, 4: Riboflavin metabolism, 5: Linoleic acid metabolism, 6: Butanoate metabolism.

CONCLUSION

JMS significantly changed the urine output of animals in the 0-6 and 6-12 groups. No change in urine pH was observed and also kidney toxicity. A new UPLC-Q-TOF method was developed for the detection of the metabolites of JMS after oral administration. The cross analysis with Venn diagram and identified the key biomarker of JMS namely naringenin-7-O-glucoside. The results showed that six major pathways are involved in the gastrointestinal system and the liver. This study demonstrated the capability of JMS prescription in the regulation of diuresis and identified a key biomarker that is responsible for its therapeutic effect.

Circadian Rhythms, Chrononutrition, Physical Training, and Redox Homeostasis-Molecular Mechanisms in Human Health

A multitude of physiological processes, human behavioral patterns, and social interactions are intricately governed by the complex interplay between external circumstances and endogenous circadian rhythms. This multidimensional regulatory framework is susceptible to disruptions, and in contemporary society, there is a prevalent occurrence of misalignments between the circadian system and environmental cues, a phenomenon frequently associated with adverse health consequences. The onset of most prevalent current chronic diseases is intimately connected with alterations in human lifestyle practices under various facets, including the following: reduced physical activity, the exposure to artificial light, also acknowledged as light pollution, sedentary behavior coupled with consuming energy-dense nutriments, irregular eating frameworks, disruptions in sleep patterns (inadequate quality and duration), engagement in shift work, and the phenomenon known as social jetlag. The rapid evolution of contemporary life and domestic routines has significantly outpaced the rate of genetic adaptation. Consequently, the underlying circadian rhythms are exposed to multiple shifts, thereby elevating the susceptibility to disease predisposition. This comprehensive review endeavors to synthesize existing empirical evidence that substantiates the conceptual integration of the circadian clock, biochemical molecular homeostasis, oxidative stress, and the stimuli imparted by physical exercise, sleep, and nutrition.

The association between chronotype profile and temporomandibular disorders among college students

BACKGROUND

Temporomandibular joint disorders (TMDs) are common in young adults, and the link between chronotype profile and TMDs is unclear.

OBJECTIVE

This study examined TMD prevalence and chronotype distribution and explored the relationship between chronotype and TMDs in young adults.

MATERIALS AND METHODS

A total of 663 students from Sichuan University completed questionnaires. Chronotype profiles were assessed using the Morningness-Eveningness Questionnaire, and TMDs were screened using the Fonseca Memory Index. To validate the findings, 68 TMD patients and 136 controls were enrolled.

RESULTS

The prevalence of TMDs was 69.7%, with significant differences among chronotype profiles. The intermediate profile was the most common chronotype. Eveningness profile was associated with higher TMDs prevalence and severity. Muscle pain and side movement difficulty scores were higher in eveningness and intermediate profiles. Female gender (OR 2.345; 95% CI 1.668-3.297) was a TMD risk factor, while morningness profile (OR 0.537; 95% CI 0.297-0.970) was protective. Validation with TMD patients and controls supported these findings, showing higher eveningness profile prevalence in the TMD groups.

CONCLUSIONS

TMDs have a high prevalence in college students, chronotype profiles shown to be associated with TMDs. Morningness is the protection factor in TMDs and PT, eveningness is a risk factor for IT.

Eveningness is associated with coronary artery calcification in a middle-aged Swedish population

Coronary artery calcification (CAC) is an established imaging biomarker of subclinical atherosclerosis, but its relationship to diurnal preference is not well studied. We investigated the association between chronotype and CAC in the Swedish CArdioPulmonary bioImage Study (SCAPIS) pilot cohort. Participants aged 50-64 years were randomly recruited and underwent extensive examination including imaging and accelerometry-assessed physical activity. 771 participants (47.3 % male, 57.6 ± 4.4 years) were included in this cross-sectional analysis. CAC was assessed by non-contrast computed tomography, and a CAC score > 10 was considered significant calcification. Self-assessed chronotype was classified as extreme morning, moderate morning, intermediate, moderate evening, or extreme evening. 10-year risk of first-onset cardiovascular disease was estimated by the Systemic Coronary Risk Evaluation 2 (SCORE2). Significant CAC was present in 29 % of the cohort. CAC prevalence increased from extreme morning to extreme evening type (22 %, 28 %, 29 %, 27 %, 41 % respectively, p = 0.018). In a multivariate logistic regression model controlling for confounders, extreme evening chronotype was independently associated with increased CAC prevalence compared to extreme morning type (OR 1.90, [95%CI 1.04-3.46], p = 0.037). When stratified by SCORE2 risk category (low: <5 %; moderate: 5 to <10 %; high: ≥10 %), significant CAC was most prevalent among extreme evening chronotypes in the low and moderate-risk groups, while chronotype seemed less important in the high-risk group (p = 0.011, p = 0.023, p = 0.86, respectively). Our findings suggest circadian factors may play an important role in atherosclerosis and should be considered in early cardiovascular prevention.

Evening Chronotype and Suicide: Exploring Neuroinflammation and Psychopathological Dimensions as Possible Bridging Factors-A Narrative Review

A chronotype is generally defined as the variability of the phase angle of entrainment, while the latter reflects the relationship between the timing of a certain rhythm (e.g., the sleep-wake cycle) and the timing of an external temporal cue. Individuals can be placed on a spectrum from "morning types" (M types) to "evening types" (E types). E-chronotype has been proposed as a transdiagnostic risk factor for psychiatric conditions, and it has been associated with psychopathological dimensions. Eveningness seems to be correlated with both suicidal ideation (SI) and suicidal behavior (SB) through several possible mediating factors. Immunological alterations have also been linked to later chronotypes and SI/SB. This narrative review aims to summarize the evidence supporting the possible association between chronotypes and suicide and the eventual mediating role of neuroinflammation and several psychopathological dimensions. A search of the literature (2003-2023) was conducted using various databases: PUBMED, EMBASE, Scopus, UpToDate, PsycINFO, and Cochrane Library. English-language articles were collected and screened for eligibility. Despite the apparent absence of a direct correlation between E-chronotype and suicidality, E-chronotype promotes a chain of effects that could be involved in an increased risk of SB, in which with neuroinflammation possibly plays an intriguing role and some psychopathological dimensions may stand out.

The Causal Relationship between the Morning Chronotype and the Gut Microbiota: A Bidirectional Two-Sample Mendelian Randomization Study

BACKGROUND

Numerous observational studies have documented an association between the circadian rhythm and the composition of the gut microbiota. However, the bidirectional causal effect of the morning chronotype on the gut microbiota is unknown.

METHODS

A two-sample Mendelian randomization study was performed, using the summary statistics of the morning chronotype from the European Consortium and those of the gut microbiota from the largest available genome-wide association study meta-analysis, conducted by the MiBioGen consortium. The inverse variance-weighted (IVW), weighted mode, weighted median, MR-Egger regression, and simple mode methods were used to examine the causal association between the morning chronotype and the gut microbiota. A reverse Mendelian randomization analysis was conducted on the gut microbiota, which was identified as causally linked to the morning chronotype in the initial Mendelian randomization analysis. Cochran's Q statistics were employed to assess the heterogeneity of the instrumental variables.

RESULTS

Inverse variance-weighted estimates suggested that the morning chronotype had a protective effect on Family Bacteroidaceae (β = -0.072; 95% CI: -0.143, -0.001; p = 0.047), Genus Parabacteroides (β = -0.112; 95% CI: -0.184, -0.039; p = 0.002), and Genus Bacteroides (β = -0.072; 95% CI: -0.143, -0.001; p = 0.047). In addition, the gut microbiota (Family Bacteroidaceae (OR = 0.925; 95% CI: 0.857, 0.999; p = 0.047), Genus Parabacteroides (OR = 0.915; 95% CI: 0.858, 0.975; p = 0.007), and Genus Bacteroides (OR = 0.925; 95% CI: 0.857, 0.999; p = 0.047)) demonstrated positive effects on the morning chronotype. No significant heterogeneity in the instrumental variables, or in horizontal pleiotropy, was found.

CONCLUSION

This two-sample Mendelian randomization study found that Family Bacteroidaceae, Genus Parabacteroides, and Genus Bacteroides were causally associated with the morning chronotype. Further randomized controlled trials are needed to clarify the effects of the gut microbiota on the morning chronotype, as well as their specific protective mechanisms.

Functional Connectivity Between Default Mode and Ventral Attention Networks Mediates the Effects of Chronotype on Daily Physical Activity

Daily physical activity (dPA) is closely related to circadian rhythm and chronotype. The functional connectivity (FC) within or between the default mode (DMN) and ventral attention network (vAN) were associated with dPA and chronotype. DMN-vAN FC was investigated for its role in chronotype and dPA. 153 participants completed the reduced version of the Morningness-Eveningness Questionnaire (rMEQ), dPA was measured via actigraphy (5-day), and then resting-state fMRI scans were performed. rMEQ scores and steps recorded by the actigraphic devices (with each hour as the time window to calculate steps for five consecutive days per hour, subsequently yielding the maximum number of steps and its corresponding time, ie, SM and SMT) represent chronotype and dPA respectively. The results found that the rMEQ scores were significantly negatively correlated with SMT. The positive correlation between the rMEQ scores and the DMN-vAN FC was significant. There were also significant positive correlations between SMT and DMN-vAN FC. Further analysis revealed that DMN-vAN mediates the relationship between chronotype and SMT. The FC of DMN-vAN may be the underlying neural mechanism through which chronotype influences dPA. These findings could support the development of reasonable activity schedules or specific intervention programs to improve physical health.

Association of nocturnal sleep duration and sleep midpoint with osteoporosis risk in rural adults: a large-scale cross-sectional study

BACKGROUND

Evidence has suggested the linkage between sleep habits and several metabolic diseases, but the association of sleep factors with bone health remains unclear, especially in regions with low economic levels. Thus, this study aimed to investigate the relationship of nocturnal sleep duration and sleep midpoint with the osteoporosis risk in a rural population.

METHOD

Eligible subjects were derived from the Henan Rural Cohort Study. The Pittsburgh Sleep Quality Index was applied to collect sleep information including sleep initiating time and wake-up time. The bone mineral density of the calcaneus was measured by the ultrasonic bone density apparatus. Multivariable logistic regression models and restricted cubic splines were utilized to evaluate the odds ratio (OR) and 95% confidence intervals (95% CI).

RESULTS

For 8033 participants, 1636 subjects suffered from osteoporosis. Compared with the reference group (7 ~ h group), the ORs and 95% CI of osteoporosis associated with duration of nocturnal sleep were 1.32 (1.10, 1.56), 1.59 (1.25, 2.01), and 1.82 (1.25, 2.65) in the 8 ~ h, 9 ~ h, and ≥ 10 h group, respectively. Additionally, the adjusted ORs and 95% CI were 1.20 (1.01, 1.44) in the early sleep midpoint group and 1.09 (0.92, 1.29) in the intermediate sleep midpoint, compared with the late. Furthermore, there was a joint effect of long duration of nocturnal sleep and the early sleep midpoint on osteoporosis.

CONCLUSION

Long duration of nocturnal sleep and early sleep midpoint were independently and jointly associated with higher risk of osteoporosis in rural areas.

TRIAL REGISTRATION

The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375.

Effects of sleep disturbances and circadian rhythms modifications on cognition in breast cancer women before and after adjuvant chemotherapy: the ICANSLEEP-1 protocol

BACKGROUND

Many patients treated for breast cancer (BC) complain about cognitive difficulties affecting their daily lives. Recently, sleep disturbances and circadian rhythm disruptions have been brought to the fore as potential contributors to cognitive difficulties in patients with BC. Yet, studies on these factors as well as their neural correlates are scarce. The purpose of the ICANSLEEP-1 (Impact of SLEEP disturbances in CANcer) study is to characterize sleep using polysomnography and its relationship with the evolution of cognitive functioning at both the behavioral and the neuroanatomical levels across treatment in BC patients treated or not with adjuvant chemotherapy.

METHODS

ICANSLEEP-1 is a longitudinal study including BC patients treated with adjuvant chemotherapy (n = 25) or not treated with adjuvant chemotherapy (n = 25) and healthy controls with no history of BC (n = 25) matched for age (45-65 years old) and education level. The evaluations will take place within 6 weeks after inclusion, before the initiation of chemotherapy (for BC patients who are candidates for chemotherapy) or before the first fraction of radiotherapy (for BC patients with no indication for chemotherapy) and 6 months later (corresponding to 2 weeks after the end of chemotherapy). Episodic memory, executive functions, psychological factors, and quality of life will be assessed with validated neuropsychological tests and self-questionnaires. Sleep quantity and quality will be assessed with polysomnography and circadian rhythms with both actigraphy and saliva cortisol. Grey and white matter volumes, as well as white matter microstructural integrity, will be compared across time between patients and controls and will serve to further investigate the relationship between sleep disturbances and cognitive decline.

DISCUSSION

Our results will help patients and clinicians to better understand sleep disturbances in BC and their relationship with cognitive functioning across treatment. This will aid the identification of more appropriate sleep therapeutic approaches adapted to BC patients. Improving sleep in BC would eventually help limit cognitive deficits and thus improve quality of life during and after treatments.

TRIAL REGISTRATION

NCT05414357, registered June 10, 2022.

PROTOCOL VERSION

Version 1.2 dated March 23, 2022.

Physical Activity Pattern of Adults With Metabolic Syndrome Risk Factors: Time-Series Cluster Analysis

Background

Physical activity plays a crucial role in maintaining a healthy lifestyle, and wrist-worn wearables, such as smartwatches and smart bands, have become popular tools for measuring activity levels in daily life. However, studies on physical activity using wearable devices have limitations; for example, these studies often rely on a single device model or use improper clustering methods to analyze the wearable data that are extracted from wearable devices.

Objective

This study aimed to identify methods suitable for analyzing wearable data and determining daily physical activity patterns. This study also explored the association between these physical activity patterns and health risk factors.

Methods

People aged >30 years who had metabolic syndrome risk factors and were using their own wrist-worn devices were included in this study. We collected personal health data through a web-based survey and measured physical activity levels using wrist-worn wearables over the course of 1 week. The Time-Series Anytime Density Peak (TADPole) clustering method, which is a novel time-series method proposed recently, was used to identify the physical activity patterns of study participants. Additionally, we defined physical activity pattern groups based on the similarity of physical activity patterns between weekdays and weekends. We used the χ2 or Fisher exact test for categorical variables and the 2-tailed t test for numerical variables to find significant differences between physical activity pattern groups. Logistic regression models were used to analyze the relationship between activity patterns and health risk factors.

Results

A total of 47 participants were included in the analysis, generating a total of 329 person-days of data. We identified 2 different types of physical activity patterns (early bird pattern and night owl pattern) for weekdays and weekends. The physical activity levels of early birds were less than that of night owls on both weekdays and weekends. Additionally, participants were categorized into stable and shifting groups based on the similarity of physical activity patterns between weekdays and weekends. The physical activity pattern groups showed significant differences depending on age (P=.004) and daily energy expenditure (P<.001 for weekdays; P=.003 for weekends). Logistic regression analysis revealed a significant association between older age (≥40 y) and shifting physical activity patterns (odds ratio 8.68, 95% CI 1.95-48.85; P=.007).

Conclusions

This study overcomes the limitations of previous studies by using various models of wrist-worn wearables and a novel time-series clustering method. Our findings suggested that age significantly influenced physical activity patterns. It also suggests a potential role of the TADPole clustering method in the analysis of large and multidimensional data, such as wearable data.

Effects of chronotype-tailored bright light intervention on post-treatment symptoms and quality of life in breast cancer survivors

PURPOSE

Bright light therapy holds promise for reducing common symptoms, e.g., fatigue, experienced by individuals with cancer. This study aimed to examine the effects of a chronotype-tailored bright light intervention on sleep disturbance, fatigue, depressive mood, cognitive dysfunction, and quality of life among post-treatment breast cancer survivors.

METHODS

In this two-group randomized controlled trial (NCT03304587), participants were randomized to receive 30-min daily bright blue-green light (12,000 lx) or dim red light (5 lx) either between 19:00 and 20:00 h or within 30 min of waking in the morning. Self-reported outcomes and in-lab overnight polysomnography sleep study were assessed before (pre-test) and after the 14-day light intervention (post-test).

RESULTS

The sample included 30 women 1-3 years post-completion of chemotherapy and/or radiation for stage I to III breast cancer (mean age = 52.5 ± 8.4 years). There were no significant between-group differences in any of the symptoms or quality of life (all p > 0.05). However, within each group, self-reported sleep disturbance, fatigue, depressive mood, cognitive dysfunction, and quality of life-related functioning showed significant improvements over time (all p < 0.05); the extent of improvement for fatigue and depressive mood was clinically relevant. Polysomnography sleep findings showed that a number of awakenings significantly decreased (p = 0.011) among participants who received bright light, while stage 2 sleep significantly increased (p = 0.015) among participants who received dim-red light.

CONCLUSION

The findings support using light therapy to manage post-treatment symptoms in breast cancer survivors. The unexpected symptom improvements among dim-red light controls remain unexplained and require further investigation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03304587, October 19, 2017.

Is evening chronotype associated with higher alcohol consumption? A systematic review and meta-analysis

A broader understanding of whether and to what extent chronotype should be considered a risk factor for alcohol consumption is needed. The aim of this systematic review was to summarize the evidence on the association between evening chronotype and alcohol consumption. A systematic search of observational studies on this association was conducted in the PubMed, Scopus, Web of Science, Cochrane Library and PsycINFO databases up to April 30th, 2023. Random-effect models estimated the pooled odds ratio (OR) of alcohol consumption according to chronotype. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Quality Assessment tool for Observational Cohorts and Cross-sectional Studies from the National Heart, Lung and Blood Institute were followed. A total of 33 studies involving 28 207 individuals (age range: 18-93 years) were included in this review. Overall, most studies indicated a higher volume and frequency of alcohol consumption in evening-type individuals than in individuals with different chronotypes. Additionally, a meta-analysis including 13 studies showed that evening-type individuals were 41% more likely to consume alcohol than those with other chronotypes (OR = 1.41, 95% confidence interval: 1.16-1.66; I2 = 38.0%). Limitations of the present findings are the predominance of cross-sectional studies and varied definitions of alcohol consumption. The available evidence supports an association between the evening chronotype and alcohol consumption. The evening-type population, especially young adults, is a specific target for educational interventions for preventing or reducing alcohol consumption.PROSPERO number: CRD42022343778.

Chrononutrition behaviors, sugar-sweetened beverage consumption, sleep quality and the association with body mass index among Malaysian women

The present study aimed to determine the association between chrononutrition behaviors, sugar-sweetened beverage intake, and sleep quality among Malaysian women. A cross-sectional study using a validated, self-administered Chrononutrition Profile Questionnaire, Beverage Questionnaire and Sleep Quality Index were conducted among 934 Malaysian women. Multinomial logistic regression was performed to obtain odds ratios of being overweight/underweight and to test the association with poor sleep quality. 40% of Malaysian women were either overweight or obese and 65.4% had poor sleep quality. We found that breakfast skipping (OR: 4.101; CI: 2.378-7.070), poor evening eating (OR: 4.073; CI: 1.631-10.186), and eating the largest meal at night (OR: 6.970; CI: 1.944-24.994) increased the odds of being underweight. On the other hand, the daily consumption of 100% fruit juices (OR: 1.668; CI: 1.058-1.731), daily consumption of sweetened coffee or tea (OR: 1.707; CI: 1.162-2.508) and consumption of diet soft drinks by 6 times or fewer (OR: 1.484; CI: 1.066-2.064) are associated with increased odds of being overweight. However, when adjusted, only poor evening latency (AOR: 16.638; CI: 1.986-139.383) revealed an increased odd of being underweight. The highest odds predicting poor sleep quality were found for eating the largest meal during dinner (OR: 3.696; CI: 1.967-6.945) and (AOR: 2.194; CI: 1.119-4.304) when adjusted. Hence, the result indicates that multifactorial impacts on women's body weight and recommendations to adjust chrononutrition and sugar-sweetened beverages intake in lifestyle must be done carefully considering other parameters together.

The rest-activity rhythm, genetic susceptibility and risk of type 2 diabetes: A prospective study in UK Biobank

AIMS

This study aims to examine the association between the rest-activity rhythm (RAR) and the incidence of type 2 diabetes (T2D).

MATERIALS AND METHODS

In total, 97 503 participants without diabetes in the UK Biobank cohort were recruited. Wearable accelerometry was used to monitor circadian behaviour. The parameters of RAR including inter-daily stability, intra-daily variability, relative amplitude (RA), most active continuous 10 h period (M10), and least active continuous 5 h period (L5) were calculated to evaluate the robustness and regularity of the RAR. The weighted polygenic risk score for T2D (T2D-PRS) was calculated. Cox proportion hazards models were used to evaluate the survival relationship and the joint and interaction effects of RAR parameters and T2D-PRS on the occurrence of T2D.

RESULTS

During 692 257 person-years follow-ups, a total of 2434 participants were documented. After adjustment for potential confounders, compared with participants in the highest quartile of RA and M10, the participants in the lowest quartile had a greater risk of T2D (HRRA  = 2.06, 95% CI: 1.76-2.41; HRM10  = 1.33, 95% CI: 1.19-1.49). Meanwhile, the highest quartile of L5 was related to a higher risk of T2D (HR = 1.78, 95% CI: 1.55-2.24). The joint analysis showed that the high T2D-PRS with the lowest quartile of RA and M10, or highest quartile of L5 jointly increased the risk of T2D (HRRA  = 4.46, 95% CI: 3.36-6.42; HRM10  = 3.15, 95% CI: 2.29-4.32; HRL5  = 3.09, 95% CI: 2.40-3.99). No modification effects of T2D-PRS on the association between the RAR parameters and risk of T2D were observed (p > .05).

CONCLUSION

The unbalanced RAR are associated with a greater risk of T2D, which are independent of known risk factors of T2D.

The prevalence of temporomandibular disorder and temporomandibular morphology among diverse chronotype profiles

This study investigates the influence of chronotype on the prevalence of temporomandibular joint disorders (TMD) and the morphology of temporomandibular joint (TMJ). According to the Morningness-Eveningness Questionnaire-Self-Assessment, the participants were divided into morning group (n = 30), intermediate group (n = 83), and evening group (n = 30). Thirty participants were randomly selected from the intermediate group for subsequent examination and measurements. The morphology of TMJs was investigated using questionnaire and clinical examination form in Diagnostic Criteria for Temporomandibular Disorder. Meanwhile, the morphological results of TMJs were measured from cone-beam computed tomography images. The prevalence rate of TMD in the morning group (23%) was significantly lower than that in the intermediate group (56.7%), while there was no difference between the evening (53.4%) and intermediate groups. As to morphological measurements, there was no significant difference among three groups in mediolateral width of condylar process, anteroposterior width of condylar process, radius of condyle, medial joint space, lateral joint space, condylar stress angle, horizontal condylar inclination, width of glenoid fossa, depth of glenoid fossa, and posterior joint space, while there was a significant difference in horizontal condylar angle (p = 0.00490), articular eminence inclination (p < .0001), anterior joint space (p = 0.0163), and superior joint space (p = 0.0004). The morphology of TMJ in the morning group was better than that in the evening and intermediate groups. An association was found between TMD prevalence, temporomandibular morphology, and chronotype.

Exercise blood pressure and heart rate responses to graded exercise testing in intermediate versus morning chronotypes with obesity

Exaggerated exercise blood pressure (BP) is linked to cardiovascular disease (CVD). Although evening chronotypes have greater CVD risk than morning (Morn) types, it is unknown if exercise BP differs in intermediate (Int) types. Adults with obesity were classified as either Morn [n = 23 (18 females), Morning-Eveningness Questionnaire (MEQ) = 63.96 ± 1.0, 54.74 ± 1.4 yr, 33.7 ± 0.6 kg/m2] or Int [n = 23 (19 females), MEQ = 51.36 ± 1.1, 55.96 ± 1.8 yr, 37.2 ± 1.2 kg/m2] chronotype per MEQ. A graded, incremental treadmill test to maximal aerobic capacity (V̇o2max) was conducted. Systolic (SBP) and diastolic (DBP) blood pressure and mean arterial pressure (MAP), rate pressure product (RPP), heart rate (HR), and rate of perceived intensity (RPE) were determined at baseline, 4 min, 6 min, and maximal stages. HR recovery (HRR; maximum postexercise) was determined at 1 and 2 min postexercise. Preexercise fasted aortic waveforms (applanation tonometry), plasma leptin, nitrate/nitrite (nitric oxide bioavailability), and body composition (dual X-ray, DXA) were also collected. Int had lower V̇o2max and plasma nitrate (both P ≤ 0.02) than Morn. No difference in preexercise BP, aortic waveforms, or body composition were noted between groups, although higher plasma leptin was seen in Int compared with Morn (P = 0.04). Although Int had higher brachial DBP and MAP across exercise stages (both P ≤ 0.05) and higher HR, RPE, and RPP at 6 min of exercise (all P ≤ 0.05), covarying for V̇o2max nullified the BP, but not HR or RPE, difference. HRR was greater in Morn independent of V̇o2max (P = 0.046). Fasted leptin correlated with HR at exercise stage 4 (r = 0.421, P = 0.041) and 6 min (r = 0.593, P = 0.002). This observational study suggests that Int has exaggerated BP and HR responses to exercise compared with Morn, although fitness abolished BP differences.NEW & NOTEWORTHY This study compares blood pressure and heart rate responses with graded, incremental exercise between morning and intermediate chronotype adults with obesity. Herein, blood pressure responses to exercise were elevated in intermediate compared with morning chronotype, although V̇o2max abolished this observation. However, heart rate responses to exercise were higher in intermediate vs. morning chronotypes independent of fitness. Collectively, this exercise hemodynamic response among intermediate chronotype may be related to reduced aerobic fitness, altered nitric oxide metabolism, and/or elevated aortic waveforms.

Effects of Chronotype and Social Jet-Lag on Neurocognitive Functioning

The chronotype, which reflects the circadian rhythm preferences of individuals in their daily activities and sleep-wake cycles, can be considered on a dimension of extreme morningism and extreme eveningism. Individuals with extreme morning and extreme evening chronotypes face many physical and psychological dangers due to accumulated sleep debt, short total sleep time and insufficient sleep efficiency. In extreme chronotypes, especially in extreme evening people, the social jet-lag effect due to the mismatch between social and circadian clocks is thought to exacerbate these dangers. More recent studies have suggested that social jet-lag and chronotype have many negative effects on cognitive functioning. The aim of this article is to review the impact of social jet-lag and chronotype on cognitive functioning.

Sleep behavior and daily activity levels in people with metabolic syndrome: effect of 1 year of metformin treatment

Impaired sleep and low daily activity levels increase the risk of developing metabolic syndrome (MS). Metformin (MET), an insulin sensitizer drug, is effective in regressing MS and has been recently studied as an adjuvant agent for managing sleep disorders. The present study aimed to assess whether 1,700 mg/day of MET treatment modifies sleep and daily activity levels in people with MS evaluated by Rest-Activity circadian Rhythm (RAR), which is the expression of 24 h of spontaneous activity parameters. A total of 133 subjects with MS, randomized into the MET (n = 65) or placebo (PLA, n = 68) group, underwent a clinical/anthropometric examination and carried out a continuous 7-day actigraphic monitoring to investigate sleep and RAR parameters at baseline and after 1 year of intervention. After 1 year of intervention, 105 subjects were analyzed. The MET group showed greater anthropometric and metabolic improvements compared with placebo, with a significant reduction in weight (p = 0.01), body mass index (p = 0.01), waist circumference (p = 0.03), and glucose (p < 0.001). With regard to sleep parameters, the MET group showed a significant increase in actual sleep time (p = 0.01) and sleep efficiency (p = 0.04) compared with placebo. There were no significant changes reported in the RAR parameters. Our study suggests that MET might be used as an adjuvant treatment for sleep disorders in people with MS.