Chronotypes in middle-aged women with polycystic ovary syndrome: A population-based study.

INTRODUCTION: Circadian rhythm disruption has been associated with the risk of polycystic ovary syndrome (PCOS), as the evening chronotype (EC) shares several traits with PCOS, including metabolic disorders, cardiovascular diseases, and psychiatric disorders. It has been suggested that the biological clock could be targeted with new, preventive, and therapeutic strategies for PCOS in women with biorhythm disorders. We evaluated inner circadian rhythmicity in middle-aged women with PCOS in a population-based setting, focusing on whether women with PCOS and an EC have a specific subtype in relation to their clinical characteristics. MATERIAL AND METHODS: The data derived from the Northern Finland Birth Cohort, a population-based longitudinal birth cohort of 12 058 individuals born in 1966. We compared the circadian phenotype between 314 women with PCOS (according to the Rotterdam criteria) and 1248 women without PCOS at age 46 years using the validated Finnish shortened 6-item Morningness-Eveningness Questionnaire (sMEQ) and the single-item self-assessed morningness-eveningness question. RESULTS: PCOS was not associated with the EC by the sMEQ (p = 0.495) or self-assessment (p = 0.303). The self-assessed morningness-eveningness values differed from the sMEQ chronotype distribution (p < 0.001), nevertheless, the most frequent chronotype was the intermediate chronotype (IC) determined by both chronotyping methods (sMEQ PCOS 47.7% vs. 45.2% non-PCOS; self-assessment PCOS 66.5% vs. 68.4% non-PCOS). The hyperandrogenic PCOS phenotypes A-C did not differ from the non-hyperandrogenic phenotype D as for the chronotype (p = 0.271). The EC was associated in both groups with depressive and anxiety symptoms (PCOS p = 0.012, non-PCOS p < 0.001) and the use of sleep medication (PCOS p = 0.017, non-PCOS p < 0.001). CONCLUSIONS: The EC was not over-represented in middle-aged women with PCOS or in the hyperandrogenic PCOS phenotypes A-C in our study. This does not support the need for chronotyping in the comprehensive assessment of women with PCOS. However, as chronotypes tend to change with aging, cross-sectional studies in different age groups are warranted to draw conclusions on the role of chronotypes in PCOS and the associated metabolic risks.

Comparison of chronotype and learning motivation in medical university students.

BACKGROUND: People differ in their preferred time for intellectual activities. Morningness-eveningness preferences describe the preferred time for performing daily activities and are determined by chronotype. Chronotype reflects circadian preference in humans and is divided into morning, intermediate, and evening types. Learning motivation is a key predictor of student success and may influence learning and study, academic performance, intention to continue medical research, and well-being. Helping students develop learning motivation may improve their educational achievement and health. There are opposing studies regarding chronotype and academic achievement. We hypothesized that chronotype affects the learning motivation of medical school students. METHODS: We used the reduced Morningness-Eveningness Questionnaire (rMEQ), and the Motivated Strategies for Learning Questionnaire (MSLQ) for Russian, Polish, Japanese, and Australian students in the first and second years of medical university. A total of 540 medical students answered the questionnaires. The MSLQ contains six subscales: intrinsic goal orientation, extrinsic goal orientation, self-efficacy for learning and performance, control of learning beliefs, task value, and test anxiety. RESULTS: The rMEQ was used to classify the students into three types, which were morning (26.7%), intermediate (60.5%), or evening chronotypes (12.7%) based on their scores. The learning motivation scores for the intrinsic and extrinsic goal orientations, task value, and self-efficacy were lower in evening chronotypes. CONCLUSIONS: Our findings suggest that the evening chronotype had a lower learning motivation than the morning chronotype. Evening-oriented students may need a more flexible schedule, and a shift of the most important courses in the university to the afternoon may help them to attain higher motivation for learning medicine.

Dependence of Cerebral Oxygenation and Task Performance on Coloured Light Exposure and Chronotype: Blue and Red Do Not Have the Same Effects on the Prefrontal Cortex.

BACKGROUND: In our previous studies, we investigated the right-left asymmetry (RLA) of cerebral tissue oxygenation (StO2) at rest in humans and the influence of the individual chronotype (i.e. individual chronobiological disposition) on StO2. The aim of the current study was to investigate (i) whether the RLA exists during a cognitive task and coloured light exposure (CLE), and (ii) how changes in StO2 induced by CLE and cognitive performance during a 2-back task are related to the subject's chronotype. METHODS: 36 healthy subjects (22 female, 14 male, age 26.3 ± 5.7 years) were studied twice on two different days. They were exposed to a sequence of blue followed by red light or vice versa in a randomised crossover study design. During CLE, subjects were asked to perform a 2-back task. We measured StO2 of the right and left prefrontal cortex (PFC) as well as the right and left visual cortex with functional near-infrared spectroscopy (fNIRS). At the behavioural level, we recorded the number of correct and incorrect answers given by the subjects. The chronotype was determined with the Horne and Östberg morningness-eveningness questionnaire. RESULTS: (i) We found that the blue and red light caused a RLA in the PFC. For red light exposure, the 2-back performance was negatively correlated with StO2 in the right PFC (r = -0.283, p = 0.016), and for blue light, exposure in the left PFC (r = -0.326, p = 0.005). (ii) 83% of subjects who performed the 2-back task at their optimal time of day according to their chronotype showed increased and higher changes in StO2 (ΔStO2 > 1%) compared to subjects who did not exercise at their optimal time of day. (iii) No correlation was found between chronotype and 2-back task performance (red: p = 0.38; blue: p = 0.42). CONCLUSIONS: We found for the first time that blue and red light exposure target different regions of the PFC during performance of a 2-back task, which can be explained by the approach and withdrawal model. These results illustrate that studying the subregions (i.e. right, left, and even centre) of the cortex provides a better understanding of the CLE effects in the human brain. Our study also shows that individual chronotype plays an important role in the individual changes in StO2 induced by CLE.

Validation of the English-language version of the Morningness-Eveningness-Stability-Scale-improved (MESSi), and comparison with a measure of sleep inertia.

The Morningness-Eveningness-Stability-Scale-improved (MESSi) assesses three components of circadian functioning: Morning Affect (time to fully awaken), Eveningness (orientation/preference for evening activity), and Distinctness (amplitude of diurnal variations in functioning). Following the original German version, translations of the MESSi (including Spanish, Turkish, and Chinese) have been validated, but validity evidence for the English-language version has been lacking. The current study tested the factor structure, internal consistency, and predicted correlations of the English-language MESSi. A sample of 600 adults from an online recruitment platform (aged 18-78, mean = 41.31, SD = 13.149) completed an online survey including the MESSi, reduced Morningness-Eveningness Questionnaire (rMEQ), Sleep Inertia Questionnaire (SIQ), and measures of personality and depressive symptoms. Exploratory factor analysis exactly reproduced the three-component structure of Morning Affect (MA), Eveningness, and Distinctness, with all items loading strongly on their respective component. Confirmatory factor analysis of this structure showed acceptable fit. The three subscales showed good internal consistency and replicated previously reported correlations with depressive symptoms, sleep inertia, sleep quality, and personality. Further factor analysis combining the items of the MESSi, rMEQ, and SIQ replicated a previously found seven-factor structure: Cognitive, Emotional, and Physiological sleep inertia (SI), Responses to SI (including one MA item); Duration of SI (one SIQ item, 3/5 MA items); Morningness-Eveningness (MESSi Eveningness items, plus 3/5 rMEQ items); Distinctness (5/5 MESSi items). In conclusion, the English-language MESSi shows sound psychometric properties, but Morning Affect may be more suitably characterised as a measure of sleep inertia duration, rather than morningness preference.

Anthropogenic noise and light pollution decrease the repeatability of activity patterns and dampen expression of chronotypes in a free-living songbird.

Anthropogenic environmental change is introducing a suite of novel disturbance factors, which can have wide-ranging effects on mean behavior and behavioral repeatability. For example, exposure to sensory pollutants, such as anthropogenic noise and artificial light at night (ALAN), may affect consistent and repeatable individual-level timing of daily activity, which is referred to as chronotypes. Although chronotypes have been increasingly documented in wild animal populations and may affect fitness, evidence for long-term stability across life-history stages and seasons is notably lacking. Furthermore, how multiple anthropogenic stressors may interact to erode or magnify the expression of chronotypes remains unclear. We tested for existence of chronotypes across life-history stages and seasons in suburban female great tits (Parus major), using emergence time from nest boxes in the morning as a proxy for activity onset. We then examined joint effects of noise pollution and ALAN on expression of chronotypes, and tested for effects of noise, ALAN, and weather conditions on mean emergence time. We found repeatability of daily activity patterns (emergence times) across life-history stages and seasons, providing evidence of chronotypes, as well as interactive effects of anthropogenic disturbance factors and weather conditions on population mean behavior. Furthermore, across-season repeatability of emergence times was approximately double in magnitude in low light and low noise conditions, relative to in conditions with higher light and/or noise pollution. Thus, joint exposure to these sensory pollutants tends to erode expression of chronotypes. This effect was driven by higher among-individual variance in the relatively undisturbed environment and collapse of this variance in the more disturbed environments. Decreased repeatability in environments with high disturbance levels may reduce potential for behavioral traits, such as chronotype, to be the target of selection and limit adaptability.

Irregular breakfast eating in type 2 diabetes mellitus is associated with greater social jetlag and poorer metabolic health.

Circadian disruption, arising from conflict between internal circadian time and behavioural sleep-wake and fasting-feeding rhythms, may contribute to the prevalence of type 2 diabetes mellitus and disease severity. Previous studies have demonstrated a link between irregular breakfast eating and poorer metabolic health. We aimed to further explore the relationships between breakfast habits, circadian misalignment (social jetlag), and metabolic parameters in a cohort of adult participants with type 2 diabetes mellitus. A total of 330 adult participants with type 2 diabetes mellitus attending for routine clinical review completed structured questionnaires to assess habitual sleep timing, chronotype, and social jetlag. Statistical analysis was via inferential groupwise approaches and path analysis to establish interdependencies of effects of social jetlag, chronotype, and breakfast eating regularity on HbA1c. 22.7% of the participants reported eating breakfast five times or fewer a week, and were categorised as irregular breakfast eaters. Compared with those who ate breakfast six or seven times a week, irregular breakfast eaters had significantly higher HbA1c and diastolic blood pressure, were younger and had greater social jetlag. In the path analysis, irregular breakfast eating exerted a direct effect on HbA1c, whilst social jetlag exerted only an indirect effect on HbA1c through breakfast eating regularity. Chronotype did not exert any effect on HbA1c, but did exert an indirect effect on breakfast eating regularity via social jetlag. Our results showed that adult participants with type 2 diabetes mellitus, who ate breakfast irregularly had poorer metabolic health and greater social jetlag. The relationship between social jetlag and glycaemic control appears to be mediated through breakfast eating habits.

Validity and Reliability of the Korean Version of Reduced Morningness-Eveningness Questionnaire: Results From a General Population-Based Sample.

BACKGROUND: Chronotype refers to individual variations in diurnal preferences that manifest as everyday behaviors, including sleep patterns. Traditionally, the Horne & Östberg Morningness-Eveningness Questionnaire (MEQ), which comprises of 19 items, has been the standard for determining chronotype. However, its length makes it cumbersome for widespread application. To address this issue, the reduced MEQ (rMEQ), a concise version containing only five items from the MEQ, was developed for a more practical approach to chronotype assessment. This study aimed to evaluate the validity and reliability of Korean version of rMEQ in a sample from the general Korean population. METHODS: The Korean version of the rMEQ comprises of items 1, 7, 10, 18, and 19 of the original MEQ. The validity of the rMEQ was assessed by correlating its scores with those of the MEQ and Munich Chronotype Questionnaire (MCTQ). Its reliability was determined by calculating internal consistency. RESULTS: A total of 3,030 individuals participated in the study, yielding an average rMEQ score of 14.0 ± 3.4. There was a substantial positive correlation between the rMEQ and MEQ scores (r = 0.859, P < 0.001). Furthermore, the rMEQ scores were significantly negatively correlated with the midpoint of sleep on free days corrected for sleep debt as measured by the MCTQ (r = -0.388, P < 0.001), indicating a robust association with chronotype. The internal consistency of rMEQ, measured using Cronbach's alpha, was 0.609. CONCLUSION: This study finds the Korean version of the rMEQ to be a valid and reliable instrument for assessing chronotype in the general population.

Exploring the Causal Association between Morning Diurnal Preference and Psychiatric Disorders: A Bidirectional Two-Sample Mendelian Randomization Analysis.

BACKGROUND: The causal connection between morning diurnal preference and psychiatric disorders remains enigmatic. Using bidirectional two-sample Mendelian randomization (MR), we aim to explore the potential causal associations between morning diurnal preference and seven prominent psychiatric disorders. METHODS: MR is a genetic epidemiological method that leverages genetic variants as instrumental variables to infer causal associations between exposures and outcomes. We obtained morning diurnal preference data from genome-wide association study (GWAS) datasets and identified 252,287 individuals as morning people. Psychiatric disorder data were sourced from the FinnGen consortium R9 dataset. Our primary analysis used the inverse-variance weighted (IVW) approach to evaluate the overall causal effect by combining the estimates from each genetic variant. Addition analyses, including weighted median, MR-Egger regression, weighted mode, and simple mode techniques were conducted to ensure robustness. RESULTS: Being a morning person is related to reduced odds of multiple psychiatric disorders, including depression or dysthymia (OR: 0.93, 95% CI: 0.88, 0.999), anxiety disorders (OR: 0.90, 95% CI: 0.84, 0.96), self-harming behaviors (OR: 0.87, 95% CI: 0.76, 0.99), substance-use disorders (OR: 0.81, 95% CI: 0.71, 0.93), alcohol dependence (OR: 0.82, 95% CI: 0.73, 0.92), alcohol use disorders (OR: 0.85, 95% CI: 0.76, 0.94), acute alcohol intoxication (OR: 0.86, 95% CI: 0.76, 0.96), schizophrenia (OR: 0.77, 95% CI: 0.65, 0.92), and schizophrenia or delusion (OR: 0.80, 95% CI: 0.70, 0.92). Alcohol dependence (OR: 0.97, 95% CI: 0.94, 0.999) and alcohol use disorders (OR: 0.96, 95% CI: 0.94, 0.99) were also related to a lower morning diurnal preference. CONCLUSIONS: Our study provides evidence that being a morning person is a protective factor for various psychiatric disorders from a genetic perspective. The results provide insights for potential targeted interventions to improve mental wellbeing.

Associations Between Physical Activity Patterns and Cardiovascular Events and Risk Factors: Cross-Sectional and Prospective Studies.

Background: Moderate-intensity physical activity (PA) is recommended for health benefits, but optimal PA timing regarding cardiovascular disease (CVD) is debated. Objectives: The authors assessed the impact of differing PA patterns on CVD risk factors and outcomes. Methods: Data from 2 surveys (S1 and S2) of the CoLaus-PsyCoLaus study (2,465 and 1,692 participants, respectively; 55.3% [54.3%] females; mean age 61.2 ± 9.7 years [64.4 ± 9.5]), conducted in Lausanne, Switzerland. PA was assessed using a wrist-worn accelerometer, and PA patterns were assessed using K-means clustering. Results: Morning PA was positively associated with hypertension (multivariable-adjusted OR: 1.36 [95% CI: 1.00-1.84]) in S1, similar trend in S2. No significant association was found between PA clusters and total, HDL-, and LDL-cholesterol or triglycerides. Morning PA was positively associated with hypolipidemic drug treatment: 1.88 (1.07-3.30) in S2. Evenly distributed daily PA was positively associated with diabetes: 1.82 (95% CI: 1.06-3.12) in S2, with a similar trend in S1. In the outcome analysis, the early morning PA cluster (7 am-12 am) and the evenly distributed daily PA cluster led to a higher risk of CVD events (HR: 3.33 [95% CI: 1.08-10.3] and 3.16 [95% CI: 1.04-9.57], respectively). Conclusions: In a population-based study, we observed a higher risk for cardiovascular events in participants whose daily PA occurred predominantly in the early morning (7 am-12 am) or was evenly distributed throughout the day. No PA pattern was consistently associated with hypertension, blood lipids, or diabetes markers.

The relationship between chronotype video game addiction and sleep quality in school-age children: A structural equation modeling approach.

This study aimed to investigate the relationship between chronotype, video game addiction, and sleep quality in school-age children using structural equation modeling. It was performed using structural equation modeling, with 545 secondary school students in northern Turkey meeting the inclusion criteria. Data were collected through face-to-face interviews utilizing the Personal Information Form, the Morningness Eveningness Scale for Children (MESC), the Video Game Addiction Scale for Children (VASC), and the Sleep Quality Scale. The findings revealed that the average video game addiction score of children was 55.22, which was associated with poor sleep quality and efficiency. Additionally, chronotype was found to mediate the relationship between video game addiction and both sleep quality (ß = 0.024; p < 0.001) and sleep efficiency (ß = -0.068; p < 0.001). The model was found to be close to acceptable levels for the variables according to the fit indices.

A Longitudinal Examination between Chronotype and Insomnia in Youths: A Cross-Lagged Panel Analysis.

Adolescence and young adulthood are transitional periods associated with significant changes and challenges, leading to a heightened vulnerability to sleep disturbances and mental health difficulties. This stage is often associated with an increased preference for eveningness, manifested as a later chronotype. The current study aimed to investigate the directionality of the association between chronotype, based on an individual's sleep-wake behaviour, and insomnia in young people using a two-wave panel design with a 12-month interval. A total of 370 participants aged 15-24 (mean age: 21.0 ± 2.0, 72.7% female) were recruited from local secondary schools and universities. Insomnia symptoms were assessed using the Insomnia Severity Index, while chronotype was measured using the Munich Chronotype Questionnaire. Temporal associations were analysed using a series of cross-lagged panel models. The best fitting and most parsimonious model indicated that a later chronotype at baseline predicts more severe insomnia symptoms at the 12-month follow-up after accounting for autoregressive effects. However, the opposite causal model, where baseline insomnia symptoms predicted the chronotype at the 12-month follow-up, was not supported. These findings suggest that a late chronotype may be a potential risk factor for the development of insomnia in young people, emphasising the importance of considering circadian factors in the prevention and treatment of sleep disturbances among this population.

Sleep Matters in Chronotype and Mental Health Association: Evidence from the UK and Germany.

BACKGROUND: There is considerable evidence supporting the elevated risk of mental health problems in individuals with evening chronotype relative to those with morning or intermediate chronotypes. Recent data, however, suggest that this risk may be explained, at least partially, by poor sleep quality. METHODS: This study aimed to further clarify the roles of chronotype and sleep quality in mental health outcomes (depression, anxiety, stress) in young individuals (18-40 years) living in the UK (n = 185) or Germany (n = 209). RESULTS: Consistent with our recent observations in a comparable North Indian sample, we found that poor quality of sleep had significantly positive associations with adverse mental health outcomes both in the UK and Germany-based samples. Significant associations between evening chronotype and poor mental health were also evident, but these associations were fully mediated by poor quality of sleep in both samples. CONCLUSIONS: These observations suggest that efforts to identify sleep disruption in a timely manner and promotion of good sleep may prevent mental health problems, especially in individuals with evening chronotype and other known risks for mental disorders.

New Insights into Health Conditions Related to Malfunctions in Clock Genes.

Chronotypes play a crucial role in regulating sleep-wake cycles and overall health. The aim of this study was to investigate chronotype, sleep quality, polymorphisms of clock genes and the level of leptin in serum. We used standardized questionnaires to assess chronotype and sleep quality. Genetic analysis was performed to determine the selected clock gene polymorphism. Serum leptin level was measured by the Elisa method. The results showed that serum leptin concentration was elevated in women, as well as in men who had a high waist-to-hip ratio (WHR) and body mass index (BMI). The evidence indicated that younger students (<22 years old) were most likely to experience poor sleep quality. Nevertheless, our multivariate analysis revealed that young age and a morning-oriented chronotype were associated with better sleep quality. We noted that clock gene polymorphisms were present in 28.6% of the participants. Moreover, polymorphisms of PER1 c.2247C>T (rs2735611) and PER2 c.-12C>G (rs2304672) genes were associated with serum leptin level and chronotype, respectively. These findings provide insights into the relationships between chronotype, sleep quality, clock gene polymorphisms and obesity risk in biomedical students. Understanding these factors can contribute to better sleep management and potential interventions to improve health outcomes in humans.

Experimentally Elevated Levels of Testosterone Advance Daily Onset of Activity in Short-Day Housed Male House Sparrows (Passer domesticus).

Seasonal changes in sleep/wake cycles and behaviors related to reproduction often co-occur with seasonal fluctuations in sex hormones. Experimental studies have established that fluctuations in circulating testosterone mediate circadian rhythms. However, most studies are performed under constant lighting conditions and fail to investigate the effects of testosterone on the phenotypic output of circadian rhythms, that is, chronotype (daily activity patterns under light:dark cycles). Here, we experimentally elevated testosterone with implants during short nonbreeding daylengths in male house sparrows (Passer domesticus) to test if observed seasonal changes in chronotype are directly in response to photoperiod or to testosterone. We fitted individuals with accelerometers to track activity across treatment periods. Birds experienced three treatments periods: short day photoperiods before manipulation (SD), followed by testosterone implants while still on short days (SD + T). Implants were then removed. After a decrease in cloacal protuberance size, an indicator of low testosterone levels, birds were then photostimulated on long days (LD). Blood samples were collected at night, when testosterone peaks, to compare testosterone levels to daily onset/offset activity for experimental periods. Our results indicate that experimentally elevated testosterone under short nonbreeding photoperiods significantly advanced daily onset of activity and total daily activity relative to daylength. This suggests that testosterone, independent of photoperiod, is responsible for seasonal shifts in chronotypes and daily activity rhythms. These findings suggest that sex steroid hormone actions regulate timing of daily behaviors, likely coordinating expression of reproductive behaviors to appropriate times of the day.

How Late Nights Influence Brain Cortical Structures: Distinct Neuroanatomical Measures Associated With Late Chronotype in Young Adults.

Chronotype is an inherent physiological trait reflecting an individual's subjective preference for their sleep awakening time, exerting a substantial influence on both physical and mental well-being. While existing research has established a close relationship between chronotype and individual brain structure, prior studies have predominantly focused on individual measurements of brain structural scales, thereby limiting the exploration of the underlying mechanisms of structural changes. This study seeks to validate previous research findings and enhance our understanding of the correlation between circadian rhythm preference and diverse cortical indicators in healthy young individuals. Magnetic resonance imaging (MRI) scans and chronotype assessments were conducted once for all participants, comprising 49 late chronotype (LC) young adults and 49 matched early chronotype young adults. The Chronotype Questionnaire was utilized to assess morningness and eveningness preferences. Surface-based analysis of structural MRI data revealed that LC young adults exhibited thinner cortical thickness of left pars orbitalis and lower cortical mean curve of right paracentral gyrus. Overall, this study represents a significant advancement in elucidating the connection between brain structure and function within the context of chronotypes.

The relationship between chronotype characteristics and fear of missing out, phubbing, sleep quality and social jetlag in medical students.

Chronotype is the temporal behavior of an organism. Social jetlag, fear of missing out (FoMO), and phubbing have received increasing attention recently and are closely related to sleep quality. This study aimed to explore the relationship between chronotype and these factors and their effects on sleep quality among medical students. The FoMO scale, phubbing behavior assessment scale, morning-evening questionnaire, Pittsburgh sleep quality index, social jetlag questionnaire, and online sociodemographic data form were filled out by 537 students participating in the study. The average age of participants was 21.34 ± 1.38 years; 43.2% were male, and 56.8% were female. The majority (66.7%) had an intermediate chronotype, 20.9% an evening type, and 12.5% a morning type. Evening chronotypes exhibited the highest levels of social jetlag, daily internet/phone use, and the poorest sleep quality and daily functioning. Women reported significantly higher levels of FoMO (p < 0.001), phubbing (p = 0.020), and daytime dysfunction (p = 0.005). Multiple regression analysis showed poor sleep quality was associated with high FoMO, high phubbing, high levels of social jetlag, and evening chronotype. Additionally, daytime dysfunction was associated with female gender, poor sleep quality, high FoMO, and high levels of phubbing (p < 0.001, F = 16.128, R2 = 0.221). These results suggest that individuals with an evening type may be susceptible to social interaction, social media use, and sleep patterns, which may negatively affect sleep quality. It has also been determined that females may be at greater risk for FoMO and phubbing. Evaluation of individuals' chronotypes will be an essential step in treating behavioral addictions such as social media, screen, and smartphone addiction.

The relationship between chronotype and mental toughness in adolescents: Is resilience a mediator?

OBJECTIVE: This study was designed to examine the mediator role of resilience in the relationship between chronotype and mental toughness in adolescents. METHODS: The descriptive correlational study was completed with 342 high school students from one school in Türkiye (mean age 17.25±1.11 years). Data were collected with the Morningness-Eveningness Scale for Children, Child and Youth Resilience Measure, and Mental Toughness Scale for Adolescents. Hierarchical regression analyses with PROCESS Model 4 were used to evaluate the mediator effect. RESULTS: It was observed that the morning chronotype tendency increased resilience (p < 0.001) mental toughness (p < 0.001). Higher resilience led to increased mental toughness. When the mediation effect was examined, resilience was a full mediator in the relationship between chronotype characteristics and mental toughness (ß=0.396; p = 0.000). CONCLUSIONS: According to these results, a morning chronotype tendency in adolescents increases their resilience and, therefore, mental toughness. These results suggest that effective methods for enhancing mental toughness in adolescents should be multifaceted. Additionally, it highlights the importance of identifying and regulating chronotype tendencies among adolescents, while also emphasizing the need to increase resilience in this demographic.

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.

Investigating the interplay of chronotypes, neuropsychiatric dimensions, demographic and clinical characteristics and disability in migraine patients: A cross-sectional assessment.

The study investigated associations between chronotypes (Morning [M], Neither [N], Evening [E]), sociodemographic characteristics, body mass index (BMI), smoking habits, years with migraines, sleep quality (PSQI), anxiety (HADS-A), depression (HADS-D), migraine disability (MIDAS), headache frequency, and pain intensity (VAS) in 80 individuals with migraine. Significant age differences emerged (p < 0.001), with M-types being the oldest. BMI also varied, with M-types presenting the highest median BMI (p = 0.005). While migraine duration and headache frequency showed no significant variance, sleep quality did, with E-types reporting the poorest sleep (p = 0.030). Anxiety and depression were significantly worse in E-types (HADS-A: p = 0.002; HADS-D: p = 0.010). Differences in MIDAS levels were notable (p = 0.038); however, differences in MIDAS scores were not significant (p = 0.115). Pain intensity varied, with E-types experiencing the most severe pain (p = 0.009). Post-hoc analysis showed higher MIDAS scores in E-types compared to N-types (χ2 = 6.56, p = 0.038, ε2 = 0.0831). The findings highlight the need for thorough patient evaluations and tailored care, considering the complex interplay of factors affecting migraine severity, particularly among different chronotypes.

Chronotype and lifestyle in the transition to adulthood: Exploring the role of sleep health and circadian misalignment.

OBJECTIVES: The present study aimed at exploring the association between eveningness and lifestyle-related variables, that is, body mass index, alcohol, and cigarette consumption, in adults (18-40years), focusing on the possible moderator effect of age and the role of sleep disturbances and circadian misalignment (social jetlag). METHODS: A web-based survey was administered to 437 participants, covering demographics, lifestyle-related variables, chronotype, sleep quality, and daytime sleepiness. A subset of 206 participants wore a wrist actigraph for a week, allowing the creation of a sleep health index within the RU-SATED framework. Regression analysis was used to investigate the associations between chronotype and lifestyle-related outcomes, accounting for social jetlag and sleep health; and to explore the lifestyle trajectories over time. RESULTS: Evening chronotypes showed higher body mass index levels, consumed more alcohol, and smoked more cigarettes than other circadian typologies, in particular after 25 years of age. Poor sleep health and social jetlag significantly contribute to explaining evening types smoking behavior, while not affecting body mass index levels. Social jetlag plays a more important role compared to sleep disturbances and eveningness in predicting more detrimental drinking and smoking behavior. CONCLUSIONS: Participants who maintain the evening trait past the age of 25years are more prone to adopt an unhealthy lifestyle, especially if experiencing poor sleep health and circadian misalignment. Circadian preferences and sleep health should be considered when planning interventions aimed at promoting healthy lifestyles in adults aged 18-40years. Further investigations should explore the effect of modifications in lifestyle in the prevention of noncommunicable diseases.