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Objective: We conducted a retrospective cohort study to explore the relationship between chronotype measured by the total Morningness-Eveningness Questionnaire (MEQ) score and incident cancer., Methods: We used clinical and provincial health administrative data on consecutive adults who underwent a Level 1 Polysomnography (PSG) and completed the MEQ between 2010 and 2015 in an academic hospital (Ontario, Canada) and were cancer-free at baseline. Cancer status was derived from the Ontario Cancer Registry. Individuals were followed until death or March 31, 2020. We used multivariable Cox cause-specific regressions to address the research objective., Results: Of 3,004 individuals, 1,781 were analyzed: a median age of 54 years (IQR: 40-64) and 838 (47.1%) men. The median total MEQ score was 63 (IQR: 55-69); 61 (3.4%) were classified as evening (≤41), 536 (30.1%) as intermediate (42-58), and 1,184 (66.5%) as morning chronotypes (≥59). Over a median of 7 years (IQR: 5-8), 120 (6.7%) developed cancer. A U-shape relationship was found between the total MEQ score and an increased hazard of incident cancer, controlling for PSG measures of sleep apnea severity and sleep architecture, demographics, and comorbidities. Compared to the median of 63.0, a total MEQ score greater or less than the median was associated with an increased hazard of incident cancer, with the largest effect for those with a total score ≥76 (e.g., HR of a MEQ total score of 78 vs. 63: 2.01, 95% CI: 1.09-3.71)., Conclusion: The U-shaped curve may reflect deviations from a standard circadian tendency, which may stress biological systems and influence malignancy risk., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Attention-deficit/hyperactivity disorder and an evening chronotype are both common among college students, and there is growing interest in understanding the possible link between attention-deficit/hyperactivity disorder and circadian function. However, mixed findings have been reported, and many of the existing studies have used small samples that were unable to examine chronotype across attention-deficit/hyperactivity disorder presentations. Participants were 4751 students (73% female; 80% White), aged 18-29 years (M = 19.28, SD = 1.50), from five universities who completed measures assessing attention-deficit/hyperactivity disorder, depressive and anxiety symptoms, as well as the Morningness-Eveningness Questionnaire to assess chronotype (categorical) and circadian preference (dimensional). Participants with either attention-deficit/hyperactivity disorder predominantly inattentive presentation or attention-deficit/hyperactivity disorder combined presentation had higher rates of being an evening type (47.2% and 41.5%, respectively) than participants without elevated attention-deficit/hyperactivity disorder (28.5%), and participants with attention-deficit/hyperactivity disorder predominantly inattentive presentation also had higher rates of being an evening type than participants with attention-deficit/hyperactivity disorder predominantly hyperactive-impulsive presentation (30.7%). Dimensional analyses indicated that attention-deficit/hyperactivity disorder inattentive symptoms were more strongly associated than hyperactive-impulsive symptoms with eveningness preference. Finally, greater eveningness preference strengthened the association between attention-deficit/hyperactivity disorder inattention and depressive symptoms but not anxiety symptoms. This is the largest study to document that college students with elevated attention-deficit/hyperactivity disorder symptoms are more likely to be evening types than other college students, and inattentive symptoms in particular are associated with later circadian preference., (© 2023 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

The aim of the present work was to compare two circadian questionnaires: the Preference Scale (PS) and the reduced version of the Morningness-Eveningness Questionnaire (rMEQ). A sample of 849 (35.10% men) university students, 421 of whom were Spanish (27.55% men; mean age 21.07  +  2.31) and 428 Italian (42.52% men; mean age 23.26  +  3.01), were administered both questionnaires. Gender (higher morningness in women) and nationality (higher eveningness in Spaniards) differences were replicated with rMEQ but not with PS, in which an inverse association between nationality and circadian preference was observed (i.e. higher morningness in Spaniards). Taking into account that the formulation of the rMEQ items, with its specific times, makes the answers less influenced by socio-cultural bias, we conclude that rMEQ is preferable to PS when evaluating circadian preference in young adults.

Introduction The link between sleep and cognitive processes, such as memory and learning, continues to be one of the most intriguing and perplexing theories. Undergraduate medical students in their first year are particularly vulnerable to sleep disturbances. Academic achievement and learning have been linked to sleep patterns, which include not only the quantity and quality of sleep but also the timing of sleep in relation to the natural sleep onsets, or chronotypes. There have been conflicting reports on the outcomes of sleep and relatively fewer researches focused on the impact of chronotypes on learning and academic achievement among medical students. The current study thus sought to determine the chronotypes of medical students, evaluate the quantity and quality of sleep, and determine the impact of these factors on learning and academic performance. Methods The study was conducted in the Department of Physiology, All India Institute of Medical Sciences (AIIMS) Gorakhpur, India. Sleep health was assessed in 167 first-year medical students using the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), morningness-eveningness questionnaire (MEQ), and sleep log books. Learning and memory assessment was performed using Raven's progressive matrices test. Grade point average (GPA) was used to assess their academic performance. The relationship of sleep scores with GPA and RPM scores were obtained by linear regression analysis. One-way analysis of variance (ANOVA) and unpaired t-test were used to investigate other comparisons among categories of chronotypes and those of mean GPA. A p-value of <0.05 was considered as significant. Results The mean GPA and RPM scores obtained in the groups with PSQI ≥ 5 (2.67 ± 1.1, 49.51 ± 6.24, respectively) and PSQI < 5 (3.15 ± 0.59, 54.73 ± 4.01, respectively) and those in the group with ESS ≥ 10 (2.72 ± 1.17, 50.97 ± 5.92, respectively) and ESS < 10 (3.15 ± 0.6, 54.18 ± 3.91, respectively) varied with statistically significant differences (p < 0.05). Statistically significant R-squared values for the relationship of PSQI and ESS scores with RPM and GPA scores were obtained. No correlation between academic grades and chronotype was found. Poor GPA scores were found to be associated with reduced mean sleep duration for one week before the exams. Conclusion Learning and academic performance are negatively impacted by poor sleep quality and daytime sleep dysfunction. No definite evidence for the association of sleep chronotypes with the learning and memory could be attained. Higher test performance is more closely linked to the average sleep length over a duration of time preceding the exams., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Gupta et al.)

The aim of this study was to detect whether the COVID-19 pandemic has caused changes in the sleep cycle (subjective sleep shifts) of high school students divided into a sample of young women - W ( n  = 1999, age = 17.65 ± 2.39 y) and young men - M ( n  = 1094, age = 17.49 ± 1.74 y) in Slovakia depending on circadian preference in comparison with the term before COVID-19. The present cross-sectional study employed a self-reported standardized questionnaire (Morningness-Eveningness Questionnaire) to study circadian preference, which was complemented by a question focused on subjective sleep shifts before and during the pandemic. The results revealed significant strong dependence between circadian preference and subjective sleep shift in both W ( χ 2 (8)  = 153.1, p  < .01, Cramer's V = .20, p  < .01) and M ( χ 2 (8)  = 98.3, p  < .01, Cramer's V =.21, p  < .01). The delay of the sleep cycle has mainly become apparent in the case of definite evening types (W: 75.7%; M: 71.8%) and moderate evening types (W: 83.1%; M: 70.3%). The delay also prevailed in the intermediate types (W: 61.9%; M: 53.8%). Subjective sleep shifts were not confirmed (W: 93.8%; M: 35.3%) in the definite morning type. The sleep cycle was changed to earlier hours of definite morning types (W: 6.3%; M: 52.9%). It is necessary to focus on definite and moderate evening types and regulate the unsuitable state to time shift of the sleep cycle.

Background: Perinatal depression (PND) is a severe complication of pregnancy, but there are no established risk factors predicting the disease. Evening chronotype has been associated with unhealthy lifestyle habits and adverse outcomes during pregnancy. In this study, we aimed to clarify whether chronotype can predict symptoms and/or occurrence of PND., Methods: Two hundred ninety-nine women were followed-up from the first trimester of pregnancy until 6 months postpartum. Chronotype was assessed at baseline using the MEQ, while mood was repeatedly assessed by depression rating scales (EPDS, HDRS, MADRS). The influence of time and chronotype on EPDS, HDRS and MADRS, was estimated by constructing multilevel linear mixed regression models. A Cox proportional-hazard regression model was built to evaluate the association between chronotype and incidence of depression., Results: Chronotype modulated PND symptom severity depending on time of assessment, with evening chronotypes having a higher risk for developing PND symptoms, as assessed by EPDS, at postpartum visits V4 (5-12 days) and V5 (19-26 days). These also had less healthy lifestyle habits and were more likely to suffer from gestational diabetes mellitus and undergo cesarean delivery as compared to other chronotypes., Limitations: Only a minority of women were classified as evening chronotypes. The long follow-up phase of the study led to missing data., Conclusions: Pregnant evening chronotypes show unhealthy lifestyle habits and sociodemographic characteristics commonly associated with a higher risk for PND. They also have a higher risk of developing PND symptoms in the first month after delivery. Chronotype should therefore be routinely assessed during pregnancy to identify women potentially at risk for developing PND., Competing Interests: Conflict of interest None., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Objective: To investigate the circadian rhythms of patients with major depressive disorder (MDD) pre-treatment and post-treatment to analyse possible influencing factors., Methods: In this study, we recruited 154 patients in the acute phase of MDD from 10 psychiatric centers in the province. The patients were divided into a morning chronotype group (16-41 points), an intermediate chronotype group (42-58 points) and an evening chronotype group (59-86 points), according to the total scores obtained from the morningness-eveningness questionnaire (MEQ). They were treated randomly with antidepressants, either selective serotonin reuptake inhibitors or agomelatine, for 12 weeks and were evaluated using the MEQ, the 17-item Hamilton Depression Rating Scale (HAMD-17), the Hamilton anxiety scale, the Snaith-Hamilton pleasure scale (SHAPS), the multidimensional fatigue inventory (MFI-20) and the Pittsburgh sleep quality index at the baseline and then at 2, 4, 8 and 12 weeks. The results were analysed by Logistic regression analysis and repeated-measures analysis of variance., Results: The baseline detection rates for the evening, intermediate and morning types were 14.93%, 56.5% and 28.57%, respectively. HAMD-17 scores were significantly lower at weeks 2, 4, 8, and 12 after treatment in patients with different concurrent phenotypes compared with those before treatment (P<0.05). There were significant differences in gender, age, body mass index, whether depression was first-episode, type of medication, baseline-MEQ and baseline-SHAPS in the chronotype change group compared with the post-treatment chronotype unchanged group (p<0.05). Logistic regression analysis showed that medication type (P=0.047), baseline MEQ (P=0.001) and baseline SHAPS (P=0.001) were risk factors for improvement in circadian rhythm after treatment for depression., Conclusion: Circadian rhythm disturbances can be adjusted to a normal pattern with effective antidepressant therapy. The medication type, baseline MEQ and baseline SHAPS scores were the influencing factors for the recovery of circadian rhythm disorders., Competing Interests: The authors report no conflicts of interest in this work., (© 2022 Guo et al.)

Background: Previous studies showed that some dietary indexes are the most important reasons to increase the incidence and spread of mental health disorders and circadian rhythm. We aimed to assess the association between the phytochemical index with circadian rhythm and mental health disorders in obese and overweight women., Methods: Participants were selected from different health centers by a multistage cluster random sampling method. Dietary intake was assessed by a semi-quantitative food frequency questionnaire (FFQ) with 147 items. Dietary phytochemical index (DPI) was estimated using the following formula: (daily energy derived from phytochemical-rich foods (kcal)/total daily energy intake (kcal)) × 100. Symptoms of mental health disorders were assessed using a validated depression, anxiety, stress scales (DASS) questionnaire with 21-items. The Circadian rhythm was assessed by the morningness-eveningness questionnaire (MEQ)., Results: The mean age and BMI of our participants were 35.19 and 30.48, kg/m2 respectively. After controlling for potential confounders, women in the highest tertile of phytochemical index (PI) had a lower prevalence of depression (P = 0.023) and would be rarely morning type (OR = 1.044, 95% CI 1-1.090) compared with those in the lowest tertile of the PI. In contrast, there was no association between PI and anxiety (OR = 1.001, 95% CI 0.945-1.060) and stress (OR = 0.992, 95% CI 0.940-1.046)., Conclusion: We found that high adherence to PI can decrease depression and increase MEQ score. Moreover, there was a relationship between adherence to PI and circadian rhythm. However, there was no association between a high level of PI and other mental problems., Competing Interests: Declaration of competing interest None., (Copyright © 2022. Published by Elsevier Ltd.)

Background: Chronotype influences several physiological systems, including the immune system and the hypothalamus-pituitary-adrenal (HPA)-axis. Previous research has shown that evening chronotype is associated with adverse metabolic health outcomes and obesity. However, the exact mechanisms underlying the observed differences in metabolic function between "morning" and "evening" types remain to be explored., Objective: To investigate the relationship of chronotype with inflammatory and neuroendocrine stress markers and to explore their mediating and moderating roles in the association between chronotype and body mass index (BMI)., Methods: Twenty-eight healthy young adults (50% women), mean age 23.8 ± 3.3 (SD) years, underwent a standardized laboratory stress test (Trier Social Stress Test, TSST). Concentrations of plasma C-reactive protein (CRP) at baseline and of salivary cortisol before and after the onset of the stressor were analyzed. Heart rate was measured continuously. Chronotype was assessed with the Morningness-Eveningness Questionnaire (MEQ)., Results: Lower MEQ scores (i.e. evening tendency) were associated with higher BMI (r = -.40, p < .05), elevated CRP concentrations (r = -.42, p < .05) and higher cortisol responses to acute stress (r = -.53, p < .01). The relationship between MEQ score and BMI was mediated by CRP concentrations (b = -0.03, CI 95%: -0.08 to -0.007, p < .05). In addition, we observed a moderating effect of the cortisol stress response on this mediated relationship (b = 0.005, CI 95%: 0.0002 to 0.01, p < .05), such that the mediated relationship was stronger in individuals with a higher cortisol response., Conclusion: Enhanced pro-inflammatory state and a higher cortisol response to stress may underlie the effect of evening chronotype on obesity risk and adverse metabolic health outcomes., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Previous studies indicate that circadian preference is associated with various energy metabolism and metabolic disorders. However, little is known about the associations between a circadian rhythm and blood lipid levels, especially in humans., Objective: The aim of the study was to investigate whether the circadian rhythm affects serum lipid levels in Korean adults., Methods: We designed a cross-sectional study to evaluate the associations between circadian preference and blood lipid levels in Korean adults. A total of 1984 participants (range of age 19-81 years) were included in this study. Propensity scores were calculated using logistic regression with age, sex, and body mass index. A total of 435 subjects were evaluated by propensity score matching analysis, equally distributed into morningness, intermediate, and eveningness groups, each with 145 subjects. Circadian preference was evaluated by the Morningness-Eveningness Questionnaire., Results: Participants with the evening preference had significantly higher levels of total cholesterol, triglyceride, low-density lipoprotein cholesterol, and non-high-density lipoprotein cholesterol (non-HDL-C) when compared with those with morning or intermediate preference, after adjusting for confounding variables. Regarding other lipid parameters, both total cholesterol/HDL-C and low-density lipoprotein cholesterol/HDL-C in the evening preference are significantly higher than those of other circadian preferences. Evening preference was also significantly associated with a higher atherogenic index of plasma., Conclusion: Our study demonstrates that there is a significant association between circadian preference and blood lipid levels. Our findings suggest that individuals with evening preference could have a greater risk of atherosclerotic cardiovascular diseases., (Copyright © 2019 National Lipid Association. Published by Elsevier Inc. All rights reserved.)

The Morningness-Eveningness Questionnaire (MEQ) is among the most commonly used scales to measure chronotype. We aimed to evaluate psychometric properties and clinical correlates of MEQ in bipolar disorder. Patients with a clinical diagnosis of bipolar disorder (n = 53) answered questionnaires for chronotype (MEQ), mood (Quick Inventory of Depressive Symptoms-16, Altman Self-Rating Mania Scale), insomnia (Athens Insomnia Scale, AIS), and sleepiness (Epworth Sleepiness Scale). Mood was evaluated using Montgomery-Åsberg Depression Rating Scale and Young Mania Rating Scale. The MEQ showed high internal consistency with Cronbach's alpha of .85. Lower MEQ scores (eveningness) correlated with insomnia (AIS) (r = -.34, p = .013). The estimate for eveningness (13/53, 24.5%) in our study was higher than in comparable studies in the general population. Patients on lithium exhibited a higher mean MEQ score (56.0 on lithium vs 46.9 with no lithium, p = .007), whereas this score was lower for patients on an antidepressant (46.0 on antidepressants vs 52.6 with no antidepressants, p = .023). We conclude that the MEQ score is psychometrically reliable. However, future studies should further evaluate the association of medication with chronotype. Validation of categorical cut-offs for MEQ in a larger sample of bipolar patients is needed to increase clinical utility., (Copyright © 2018 Elsevier B.V. All rights reserved.)

"Morningness" and "Eveningness" represent lifestyle patterns including sleep-wake patterns. Although previous studies described a relationship between the morningness-eveningness trait and glycemic control in patients with type 2 diabetes mellitus (T2DM), the mechanism underlying this association remains unknown. The study participants comprised 725 Japanese T2DM outpatients free of history of cardiovascular diseases. Various lifestyles were analyzed using self-reported questionnaires, including morningness-eveningness questionnaire (MEQ). The relationships between morningness-eveningness trait and various biochemical parameters were investigated by linear regression analysis and logistic regression analysis. We classified the study patients into three groups, morning type (n=117), neither type (n=424) and evening type (n=184). Subjects of the evening type had high levels of alanine aminotransferase, triglyceride, fasting blood glucose and HbA1c and low high-density lipoprotein-cholesterol level in a model adjusted for age and gender. Furthermore, multivariate analysis showed that the evening type was associated with high HbA1c and estimated glomerular filtration rate even after adjustment for other lifestyle factors known to affect metabolic control. The results suggest that T2DM patients with eveningness trait are under inadequate metabolic control independent of other lifestyle factors. Thus, the evening trait of T2DM patients represents an important target for intervention to ensure appropriate metabolic function.

Aims/introduction: 'Morningness' and 'eveningness' represent the sleep-wake patterns of the circadian rhythm might also affect glycemic control in patients with type 2 diabetes. The aim of this study was to examine the relationship between the morningness-eveningness trait and metabolic parameters., Materials and Methods: The study participants comprised 101 Japanese male workers with type 2 diabetes treated in an outpatient clinic. Blood samples were obtained, and a morningness-eveningness questionnaire (MEQ), where a high score represents morningness; and the Pittsburg Sleep Quality Index (PSQI), where the higher the score the worse the sleep quality, were carried out., Results: MEQ correlated positively with age, and high-density lipoprotein cholesterol (HDL-C), and negatively with glycated hemoglobin (HbA1c) and PSQI. Multivariate regression analysis showed that MEQ was significantly associated with HbA1c and HDL-C. In addition, we classified the study patients into three groups: 'morning type', 'neither type' and 'evening type' according to the sum of the MEQ score, and analyzed the difference between morning type (n = 32) and evening type (n = 11). We found that HbA1c, low-density lipoprotein cholesterol and PSQI of the morning type group were significantly lower than those of the evening type group., Conclusions: The present study suggests that 'eveningness' type male Japanese workers with type 2 diabetes suffer inadequate glycemic control.