Chronobiology International最新文献

This study investigated the impact of age on morningness-eveningness (ME) and its inter-individual variability, with a focus on sex-specific patterns. A sample of 2890 participants aged 12-94 years (55.85% female) completed the Composite Scale of Morningness. Multiple linear regression analyses revealed a significant Age × Sex interaction, indicating distinct age-dependent patterns for males and females in both ME and its inter-individual variability. We conducted segmented regression analyses to explore these dynamics further and identify breakpoints. Eveningness increased across adolescence, with both males and females reaching peak lateness at 20 years. Morningness increased thereafter until 64.94 years for females and until 59 years for males. Following these sex-specific breakpoints, morningness remained constant for females and increased at a reduced rate for males. After the age of 48, males exhibited greater morningness than females. Inter-individual variability in ME (VME) changed with age, increasing until 33 years for men and 36.80 years for women, followed by a decrease for both sexes. From 50.30 years onward, females showed greater VME compared to men. This study suggests that ME and VME shift across age, and differences between sexes were observed from middle age onwards. Diurnal preferences are likely influenced by internal and environmental variables.

Physical inactivity may exacerbate the adverse health effects associated with shift work. We investigated the association of shift work with leisure-time physical inactivity (LTPI). A cross-sectional analysis included 33 983 adults from National Health Interview Survey who self-reported their work schedule and leisure-time physical activity. Participants were classified in to two groups as either (a) inactive or (b) insufficiently/sufficiently. Prevalence ratios were derived using SUDAAN. Analyses were stratified by sex. In this sample of U.S. workers, 27% were shift workers, 26% were physically inactive, and 47% did not meet recommended levels of leisure-time physical activity. Inactivity level was 23% higher in women than in men among shift workers but did not differ by sex among daytime workers (PR = 1.02, 95% CI: 0.96-1.07). Evening or night work was associated with higher LTPI among women but not men. LTPI was 17% higher in women working the night shift, and 24% higher in those on the evening shift compared to those working the daytime shift. These findings suggest that shift work may contribute to increased LTPI, with effects that may be particularly pronounced in women. Interventions addressing LTPI among shift workers may help mitigate the adverse health effects that have been linked to shift work in prior studies.

Numerous studies have shown the influence of the moon cycle on biological functions in farm animals, suggesting that predicting calving distribution could enhance survival rates by improving management practices in animal production. This study builds on previous research by examining the impact of the lunar cycle on calving frequency, gestation length, birth weight, and calf sex in artificially inseminated cows. We analyzed 121,276 records from dual-purpose crossbred cows across 36 farms along the western margin of Lake Maracaibo basin, Venezuela. The lunar cycle was divided into 30 periods of 0.984 days each and further categorized into four phases: 1) 1.97 days around the new moon; 2) 12.8 days during the crescent phase; 3) 1.97 days around the full moon; and 4) 12.8 days during the waning phase. Data were analyzed using a logistic regression and the general linear model in SAS, comparing proportions and means with contrast and general linear model tests, respectively. There was no association between the lunar cycle and the sex of calves. However, calvings distribution across the lunar month showed notable peaks 2 days around both the new and full moons, a pattern consistent regardless of the number of calvings or gestation lengths. In addition, significant differences were observed between the days surrounding the new (1) and full (3) moons compared to the other lunar phases (2 and 4). Moon cycle also influenced gestation length and calf birth weight. This study expands previous findings and demonstrates that the lunar cycle consistently affects certain reproductive traits in inseminated dual-purpose cows, including gestation length, calf birth weight, and calving distribution, with practical implications for cattle operations.

The present study explores the effect of differential food treatment on the migratory phenology of redheaded bunting (Emberiza bruniceps). Birds were divided into four groups (N = 10 each) on the basis of the food provided. Group I was fed with seeds of Setaria italica (kakuni), while group II was provided with protein-rich diet (combination of; 3 parts egg white and 1 part kakuni seeds). Likewise, group III birds received fat-rich food (i.e. 3 parts sesame seeds and 1 part kakuni seeds). Birds in group IV were provided with all three food items mentioned above separately. The experiment continued until the appearance of 7 cycles of zugunruhe. The results reveal a significant impact of food on locomotor activity and food intake behavior of birds, although the physiological response as demonstrated by a gain in body mass, fat score, and gonadal recrudescence was mainly influenced by the LHS. Besides the behavioral and physiological responses, the hypothalamic expression of neuropeptide Y (NPY) in infundibular complex (INc) was significantly high for group IV, highlighting the importance of "variety" in food intake. Thus, the present study suggests a significant role of food in influencing seasonal responses via hypothalamic NPY stimulation.

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.

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.

Aberrant light/dark (LD) cycles are prevalent in modern society due to electric light usage, leading to mood disorders from circadian disruption or misalignment. However, research on the physiological and behavioral effects of LD variations on brain neurotransmitters is limited. We investigated the effects of extreme LD cycles on body weight (BW), core body temperature (T_core), locomotor activity (ACT), emotional behaviors, and monoamine levels (noradrenaline [NA], dopamine [DA], and serotonin [5-HT]) in male Wistar rats that were exposed to 1 month of either long light phase (20 L:4D), long dark phase (4 L:20D), or normal (12 L:12D) LD cycles. The 20 L:4D rats exhibited blunted rhythms, with decreased amplitude and advanced/delayed acrophase in T_core and ACT, alongside increased BW. The 4 L:20D rats showed circadian misalignment, with increased/decreased amplitude in T_core or ACT and delayed acrophase in T_core and ACT, also gaining BW. In the 20 L:4D group, NA and 5-HT levels decreased in the suprachiasmatic nucleus and amygdala, respectively, while the 4 L:20D group had increased DA and 5-HT levels in the caudate putamen and dorsomedial hypothalamus, respectively. Open field and social interaction tests indicated anxiety-like behaviors in both test groups. Overall, each extreme LD cycle affected T_core, ACT amplitude, acrophase, and monoamine levels differently, inducing anxiogenic responses.

One of the main challenges in translating chronobiology research into clinical practice is represented by differences in how basic scientists and clinicians evaluate evidence. The workshop "Assessing Evidence in Translational Chronobiology," which was held at the University of Surrey in June 2023, addressed this issue by bringing together basic scientists and clinicians to evaluate evidence on two specific topics: the impact of Daylight Saving Time (DST) on road traffic accidents and the relationship between delayed school start times (SSTs) and sleep duration in high school students. A comprehensive literature search was conducted for discussions during the workshop, which is presented in this review. The studies on both topics were analyzed from varying perspectives, including that of a chronobiologist and a transportation engineer for the DST-centered question, and that of a chronobiologist and an evidence-based medicine expert for the SSTs-centered question. The workshop audience, acting as a Delphi panel, attempted to produce statements/recommendations. It was concluded that most studies suggest that sleep duration benefits from delayed SSTs in high school, while less obvious results were obtained regarding the effect of DST on road safety.

Circadian rhythm-related individual differences such as chronotypes (morningness/eveningness) are associated with mental health though not elucidated in circadian-disrupted populations such as flight attendants. International flight attendants (n = 288) aged 21 to 55 (70.8% female, 76.4% white) completed an online survey assessing chronotypes, attachment, depression, and anxiety to investigate the associations between these variables. Results showed a prevalence of intermediate (41.6%) and evening types (40.6%). Evening chronotype was associated with and significantly predicted depression but not anxiety. Individuals who scored higher in attachment anxiety or avoidance had higher levels of depression and anxiety. Exploratory mediation showed that attachment avoidance partially mediated the relationship between anxiety and depression. Overall, chronotypes and attachment are implied as transdiagnostic factors for mental health outcomes and highlighted using a Chrono-Attachment Health Model. Further research is needed to confirm these findings among flight attendants and shift workers.

This study investigated the quality and duration of sleep among shift-working nurses. In this cross-sectional survey, nurses from eight units across two tertiary hospitals in South Korea's capital region participated. We collected data on sleep quality and duration from 117 nurses. We used the Mann-Whitney test, analysis of variance, or the Kruskal-Wallis test to analyze differences in sleep quality and duration across different shifts. The nurses generally reported low sleep quality, with sleep disturbances being the most common issue. The worst subjective sleep quality was associated with the night shift, while the shortest sleep duration was reported for the day shift. Nurses working two consecutive night shifts reported the poorest sleep quality and shortest sleep duration. The quality and duration of sleep for shift-working nurses varied depending on the shift type. There were also differences based on the arrangement of multiple consecutive shifts. The findings of this study suggest that planning for nurses' shift work should consider sleep quality and duration. Specifically, nurses working the night shift reported poor sleep quality and duration, indicating a need for strategies to ensure they get sufficient rest after their shifts.