Chronobiology International最新文献

Actigraphy provides a unique method for objectively measuring sleep activity patterns, but confusion remains about how to use actigraphy data to determine chronotype. To determine the most suitable parameter, this study made a systematic comparison of actigraphy-derived parameters: the average midpoint of sleep of all record days (aMS-acti), cosine parameter (Bathyphase), and non-parametric parameter (L5-mid) in terms of the consistency with subjective chronotype parameters, test-retest reliability, and external validity. More importantly, we proposed multiple Munich Chronotype Questionnaire (MCTQ)-based actigraphy parameters: considering the difference between weekday (MSW-acti) with weekends (MSF-acti) and the sleep debt (MSFsc-acti). The study collected 5 days of actigraphy and scale data from 1,055 young adults, 138 of whom participated in the retest 2 years later. The results showed that, in terms of consistency with subjective chronotype, aMS-acti generally performed better than other actigraphy parameters. In addition, aMS-acti had the highest test-retest reliability and was more closely related to the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and Self-Rating Depression Scale (SDS). The results suggest that the simplest parameter (aMS-acti) is superior to traditional cosine and non-parametric parameters and MCTQ-derived parameters for short-term assessment of chronotype.

Plasma glucose spikes affect cardiac autonomic modulation resulting in a decrease of heart rate variability (HRV). We hypothesize that a later chronotype or a higher morning plasma melatonin level is associated with larger decreases of HRV following an early high glycaemic index (GI) breakfast. In persons with an early (n = 21) or a late (n = 15) chronotype who consumed a high GI breakfast at 7 a.m. glucose data were continuously monitored. Time domain HRV parameters were calculated from blood volume pulses derived by wireless wrist worn multisensor. HRV changes (values after minus values before breakfast) were associated with chronotype by multivariable linear regression adjusted for age, sex and baseline levels. Morning plasma melatonin levels were determined from samples drawn on the run-in day. Time domain parameters indicate a higher HRV before high GI breakfast in both chronotypes. A later chronotype tended to be associated with smaller decreases of mean interbeat intervals (p = 0.08) only; no associations were seen with morning melatonin levels. This exploratory analysis in a small sample provides a first indication that in young healthy adults later chronotype might be associated with reduced ANS activation following a high GI breakfast. Future studies should elucidate whether this indicates parasympathetic or sympathetic inhibition.

Temporal patterns of eating and diet composition are influenced by factors including circadian preference (chronotype) and work schedule, yet their combined influence is unknown. We investigated relationships between chronotype, temporal eating patterns (duration of eating window (DEW), time of first (FEO) and last (LEO) eating occasions), and diet composition on workdays (WD) and work-free days (FD). Non-shift workers (n = 39) completed the Chrononutrition Questionnaire (CNQ) (age: 38.8 ± 17.2 years, BMI: 24.8 ± 4.78 kg/m², 82% female) that captures chronotype and temporal eating patterns, and returned work diaries (work schedule) and 7-day food diaries (diet composition) after 2 weeks. Twenty-nine participants provided dietary data for at least two work and work-free days. Later chronotype was associated with later FEO on FD (r_s = 0.45, p = 0.004), later LEO on FD (r_s = 0.60, p < 0.001) and WD (r_s = 0.61, p < 0.001), and longer DEW on WD (r_s = 0.37, p = 0.024). Relationships between chronotype and diet composition were small. Later FEO was associated with higher % energy from fat (r_s = 0.39, p = 0.043) and lower fibre intake (r_s = -0.69, p < 0.001) on WD. Later chronotypes had shorter and later eating windows on FD than WD. Our findings suggest that relationships between chronotype, temporal eating patterns, and diet composition differ by day type. Further investigation may inform dietary strategies that are day-specific.

Models of shift work and health suggest that individual differences in circadian rhythm characteristics may moderate the relationship between night shift work and injury, but this argument has not been directly tested. In this study, we tested the efficacy of two circadian rhythm characteristics-vigour and flexibility-as moderators of the path between shift work and injury. In addition, we aimed to replicate the association between vigour, flexibility, and alertness by time of day, and the measurement properties of the Circadian Type Inventory. We recruited 401 healthcare workers from Australia and Great Britain. After controlling for confounding variables, the results showed that vigour moderated the association between shift work and injury. Participants with values of vigour at the mean (β = 0.5120, p < 0.0013, 95% CI = [0.2018, 0.8223) and one standard deviation below the mean (β = 0.9048, p < 0.0001, 95% CI = [0.4648, 1.3447] reported significantly more injuries. No moderation was found for flexibility. Significant differences in alertness by time of day were observed in participants with higher levels of vigour compared to lower levels of vigour. No differences in alertness were observed for the flexibility scale. These results indicate that vigour may be a robust indicator of shift work tolerance. We replicated the posited two-factor structure of the Circadian Type Inventory, found the scales to have good reliability, and established for the first time, criterion-related validity for the vigour scale.

Anxiety is being increasingly linked to circadian rhythms, including chronotype, in addition to its intricate links with sleep quality. Emotional competence is thought to be a strong predictor of wellbeing and mental health. This study aimed to examine whether a combination of chronotype, sleep quality, and intrapersonal emotional competence can predict anxiety in emerging adults (aged 18-29), who have the greatest prevalence of adult anxiety. One hundred and seventeen participants completed self-report measures of chronotype, sleep quality, emotional competence, and anxiety. A multiple linear regression, with anxiety as the criterion variable, showed that while all predictors were significant, sleep quality was the strongest predictor of anxiety. A later chronotype, poorer sleep quality and lower intrapersonal emotional competence were related to higher anxiety. Thus, integrating intrapersonal emotional competence and chronotype considerations into interventions may address the interplay between sleep quality and anxiety in emerging adults more effectively.

Sleep quality, chronotype, and mood may be closely interconnected processes. Typically, such constructs are measured independently, leaving out important information regarding their intrinsic relationships. The Sleep, Circadian Rhythms, and Mood (SCRAM) questionnaire is a promising tool for measuring sleep, chronotype, understood as diurnal preference, and depressive symptomatology, and the interrelationships between them. Anxiety has also been linked to sleep quality, chronotype, and depression, but there is currently no scale that measures these constructs together. This study aims to validate a revised version of the SCRAM questionnaire (rSCRAM), incorporating items to measure anxious mood. 486 Italian participants were involved in two studies. In Study 1, principal component analysis (PCA) identified representative anxiety elements from validated questionnaires. In Study 2, after adding the anxiety elements, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) established a 4-factor, 16-item model. The rSCRAM demonstrated excellent psychometric properties: high internal consistency (α = 0.72-0.90) and a strong test-retest reliability of the scales over 2 weeks (r = 0.73-0.82), a high correlation for convergent validity, and low correlations for divergent validity. The rSCRAM questionnaire measures the constructs for which it was created and revised. Including the anxiety scale enhances its utility in assessing mental health constructs within a single instrument.

Melatonin is produced in the pineal gland under very tight control through the influences of light and the suprachiasmatic nucleus. As such, melatonin circulates in the blood at levels <3 pg/ml during the day and is only actively secreted at night reaching levels of approximately 100 pg/ml. As a consequence of binding to plasma proteins, free melatonin appears in saliva at approximately one third the plasma concentration. Measurement of melatonin is technically challenging because of these very low concentrations and while a number of commercial immunoassay kits are available and mass spectrometry assay methods have been published, not all are fit for purpose and can lead to unreliable conclusions. In this review I discuss the aspects of pineal melatonin production that saliva melatonin reflects, the factors influencing melatonin production or metabolism, saliva collection and analysis methods. Examples are provided of the appropriate use of saliva melatonin measurements; Dim Light Melatonin Onset (DLMO) assessment, impact of light on melatonin and the monitoring of rhythms prior to specific treatments. Examples of inappropriate use of saliva melatonin measurements are also provided including the use of poorly validated assays, morning saliva collections, attempts to stimulate melatonin, and linking specific illnesses to saliva melatonin levels.

During the COVID-19 pandemic, studies reported that restricted living conditions were associated with worse subjective sleep quality. This effect might have been caused by reduced light exposure during lockdowns. We investigated light exposure levels, subjective and objective sleep and physical activity levels in older adults during restricted and free-living conditions after the pandemic. Ninety-one participants (62.7 ± 8.4 years) recruited from the community using social media with 44 participants (63.4 ± 8.9 years) completed follow-up during free-living conditions. Participants wore an actigraphy device and completed sleep diaries for 7 days during each condition. Light values were extracted in hourly bins across the 24-h period and objective and subjective sleep were compared between the conditions. There was an increase in mean 24-h light exposure during restricted-living (1103.7 ± 1024.8 lux) compared to free-living (803.0 ± 803.6 lux; p < 0.001). This was partially related to participants spending 18 min more in bright light conditions (>1,000 lux) during wakefulness in restricted living (2.6 ± 1.9 h) compared to free-living (2.3 ± 2.0 h; p = 0.036). Despite differences in light exposure, there were no significant differences in objective and subjective sleep parameters between the two conditions. More research is required to better understand behaviours related to light exposure and how this may impact on sleep.

While links between certain chronotypes and poorer health outcomes have been well established in previous studies, few studies have examined the relationship between chronotype and cellular aging. Using data from the California Teachers Study (CTS), the present study evaluates the relationship between cellular aging and chronobiology through an analysis of leukocyte telomere length (LTL) and chronotype among 817 predominantly postmenopausal women with no history of cancer and occupations not associated with night-shift work. Unconditional logistic regression models were run to estimate odds ratios (ORs) for each chronotype category, adjusted for age, ethnicity, and smoking status. Analyses were then stratified by potential modifiers to assess whether results varied among specific subgroups within the sample. Women who reported being current evening types and evening types from teen years to now were significantly less likely to have short LTL compared to women who reported being current morning types or morning types from teen years to now (OR = 0.72; 95% CI = 0.53-0.98; OR = 0.57; 95% CI = 0.39-0.84). Our results suggest that women with no history of cancer who identify as evening chronotypes may undergo decreased cellular aging compared to women in the same population who identify as morning types. Further studies on populations of postmenopausal women are warranted.

Sleep is crucial for children's health and eating habits. The decline in family meals has raised concerns about its impact on children. Previous research indicated associations between family meals and psychological health and dietary habits, but their relationship with sleep behavior is less understood. This study examined the association between family meals (breakfast and dinner), sleep patterns, and quality of life among Japanese preschoolers and elementary school students (1^st to 3^rd grade). The cross-sectional study involved 6,177 children aged 3-8 years in Japan. Mothers completed an online survey on family meal habits, sleep patterns, and the KINDL-R questionnaire to assess quality of life. Results showed that family meals were associated with sleep behaviors and KINDL scores. Multiple regression analysis indicated that family breakfast was associated with earlier bedtime and wake-up time, shorter weekend sleep duration, reduced social jet lag, and a morning chronotype, as detected by the Munich ChronoType Questionnaire. Family dinners were linked to later sleep and wake-up times and an evening chronotype. Family breakfast and dinner were associated with higher KINDL scores, with dinner having a stronger positive impact. These findings underscore the significance of family meals in associating sleep patterns and quality of life among Japanese children.