Chronotype

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...

BACKGROUND: Better understanding apathy in late-life depression (LLD) would help predicting poor prognosis of the disease such as dementia. Actimetry provides an objective and ecological measure of apathy from patients' daily motor activity. We aimed to determine if patterns of motor activity were associated with apathy and brain connectivity in networks underlying goal-directed behaviors. METHODS: Resting-state functional MRI and diffusion MRI were collected from 38 non-demented LLD subjects...

We aim to examine the association of sleep duration, sleep quality, late chronotype and circadian misalignment with glycemic control and risk of complications in young adults with youth-onset type 2 diabetes followed in the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study. Self-reported sleep duration, quality, timing, and circadian misalignment were assessed via a modified Pittsburgh Sleep Quality Index (PSQI) questionnaire, and chronotype was assessed via the Morningness-Eveningness Questionnaire (MEQ)...

Later chronotypes may be associated with lower diet quality and later timing of energy intake in paediatric age. Period of data collection of these variables may affect these parameters and inter-relationship. We aimed to assess the cross-sectional association of chronotype with a diet quality score (HEI) and caloric midpoint (time of achieving 50% of total daily energy intake), considering summer holidays, using data from the National Food, Nutrition and Physical Activity Survey 2015-2016 for 578 participants (6-14 years of age)...

PURPOSE: Glycemic response to the same meal depends on daytime and alignment of consumption with the inner clock, which has not been examined by individual chronotype yet. This study examined whether the 2-h postprandial and 24-h glycemic response to a meal with high glycemic index (GI) differ when consumed early or late in the day among students with early or late chronotype. METHODS: From a screening of 327 students aged 18-25 years, those with early (n = 22) or late (n = 23) chronotype participated in a 7-day randomized controlled cross-over intervention study...

OBJECTIVE: The purpose of this study was to evaluate the psychometric properties of the Couples' Sleep Conflict Scale, a new measure designed to identify the extent of conflict around sleep in romantic relationships. METHODS: Data from an individual sample (N = 158) and dyadic sample (N = 143 mixed-gender couples) in romantic relationships were used to examine the psychometric properties of the Couples' Sleep Conflict Scale, including internal consistency, convergent and divergent validity, and whether the factor structure differed between couples with concordant and discordant chronotypes...

OBJECTIVE: This study assesses whether chronotype is related to COVID-19 infection and whether there is an interaction with shift work. METHODS: Cross-sectional survey of 19,821 U.S. adults. RESULTS: COVID-19 infection occurred in 40% of participants, 32.6% morning and 17.2% evening chronotypes. After adjusting for demographic and socioeconomic factors, shift/remote work, sleep duration and comorbidities, morning chronotype was associated with a higher (aOR: 1...

BACKGROUND: Insomnia and eveningness are common and often comorbid conditions in youths. While cognitive behavioural therapy for insomnia (CBT-I) has been suggested as a promising intervention, it remains unclear whether it is sufficient to also address circadian issues in youths. In addition, despite that light has been shown to be effective in phase-shifting one's circadian rhythm, there has been limited data on the effects of bright light therapy and its combination with CBT-I on sleep and circadian outcomes in youths...

Phenomenon : Educational activities for students are typically arranged without consideration of their preferences or peak performance hours. Students might prefer to study at different times based on their chronotype, aiming to optimize their performance. While face-to-face activities during the academic schedule do not offer flexibility and cannot reflect students' natural learning rhythm, asynchronous e-learning facilitates studying at one's preferred time. Given their ubiquitous accessibility, students can use e-learning resources according to their individual needs and preferences...

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...

Introduction: Emerging evidence has been explored to determine the factors affecting the development of infant circadian rhythm. While fetal programming happens during the pregnancy period, external environmental cues and infant nutritional programming can have substantial effects on the infant circadian rhythm. Understanding prenatal and postnatal factors determining infant circadian rhythm can improve future interventions in optimizing maternal and infant health. Methods: This is a prospective observational cohort study, targeting 216 pregnant women from government maternity clinics in Kuala Lumpur, Malaysia...

Most studies have shown a link between chronotypes and mental health and have identified evening chronotypes (E-types) as a potential risk for depressive symptoms. However, the mechanisms behind this association remain unknown. Abnormal expression of the PER1 gene was not only associated with circadian rhythm disturbance, but also closely related to mental illness. Therefore, this study aimed to examine the association of chronotype with depressive symptoms, and further explore the moderating effects of the PER1 gene DNA methylation on chronotypes and depressive symptoms in Chinese university students...

Mosquitoes occupy a wide range of habitats where they experience various environmental conditions. The ability of some species, such as the tiger mosquito, Aedes albopictus , to adapt to local conditions certainly contributes to their invasive success. Among traits that remain to be examined, mosquitoes' ability to time their activity with that of the local host population has been suggested to be of significant epidemiological importance. However, whether different populations display heritable differences in their chronotype has not been examined...

This cross-sectional study was carried out to determine the relationship between nutrition according to chronotype and the Mediterranean diet and environmental footprints. "Morningness Eveningness Questionnaire" was used to determine the chronotype classification, and "Mediterranean Diet Adherence Screener" was used to evaluate adherence to the Mediterranean diet. In addition, the food consumption record of the participants was taken and the carbon and water footprints were calculated. A total of 472 adults with a mean age of 22...

The COVID-19 pandemic had a profound impact on the physical and mental health of healthcare professionals. The present study explored the relationship between sleep disorders, stress, coping strategies and neurobehavioral aspects among young physicians during the second wave of the COVID-19 pandemic. Through a multi-assessment approach, this cross-sectional study collected sociodemographic and occupational data from first-year resident doctors in southern Italy. Subjective sleep quality, chronotype, work-related stress, coping approach and mood state were assessed by administering validated questionnaires during face-to-face interviews...

Chronotype is a proxy sleep measure that has been associated with neuropsychiatric disorders. By investigating how chronotype influences risk for neuropsychiatric disorders and vice versa, we may identify modifiable risk factors for each phenotype. Here we used Mendelian randomization (MR), to explore causal effects by (1) studying the causal relationships between neuropsychiatric disorders and chronotype and (2) characterizing the genetic components of these phenotypes. Firstly, we investigated if a causal role exists between five neuropsychiatric disorders and chronotype using the largest genome-wide association studies (GWAS) available...

Copy number variants (CNVs) are among the largest genetic variants, yet CNVs have not been effectively ascertained in most genetic association studies. Here we ascertained protein-altering CNVs from UK Biobank whole-exome sequencing data (n = 468,570) using haplotype-informed methods capable of detecting subexonic CNVs and variation within segmental duplications. Incorporating CNVs into analyses of rare variants predicted to cause gene loss of function (LOF) identified 100 associations of predicted LOF variants with 41 quantitative traits...

PURPOSE: Misalignment between sleep opportunity and chronotype preference during adolescence may affect sleep and mental health. The aim of this study was to objectively evaluate sleep duration and social jetlag (SJL) to observe if there is a relationship with anxiety, depression, or chronotype. METHODS: Community based cohort study (n = 65) was conducted in Northern Europe. Participants recorded their sleep during the regular school schedule for 3 school nights and 2 free nights with FDA-cleared/EU Medical Device Directive (CE-02862) compliant home sleep test...

Since the discovery of the genetic origin of the circadian clock in Drosophila melanogaster by Konopka and Benzer in 1971, most of the research about the regulation of the molecular circadian clock relies on laboratory models. Additional models such as Cyanobacteria, Neurospora crassa, Arabidopsis and rodents helped chronobiologists to describe the species-specific molecular clocks and their regulation. However, the lack of tools and the difficulty to access biological samples somehow excluded human from this research landscape outside behavioural research...

Sleep timing is controlled by intrinsic homeostatic and circadian components. The circadian component controls the chronotype, which is defined by the propensity to sleep at a particular clock time. However, sleep timing can be significantly affected by external factors such as the morning alarm clock. In this study, we analysed the timing of deep and REM sleep as well as the composition of REM sleep using Fitbit sleep staging in young healthy adults ( n = 59) under real-life conditions. Sleep stage percentiles were correlated with the timing of total sleep in time after sleep onset for the homeostatic component and in clock time for the circadian component...