Chronobiology International最新文献

This study explores the relationship between loneliness, sleep chronotype (SC), and depressive symptoms (DS) in Chinese college students, with a focus on SC's mediating role. A cross-sectional survey was conducted with 1,079 college students, using validated instruments to assess loneliness, SC, and DS. Pearson correlation analysis revealed a significant positive correlation between loneliness and DS (r = 0.549, p < 0.01) and a negative correlation between SC and both loneliness (r = -0.177, p < 0.01) and DS (r = -0.206, p < 0.01). Structural equation modeling (SEM) indicated that SC partially mediated the relationship between loneliness and DS, with a significant indirect effect (β = 0.016, 95% CI: 0.003-0.035, p = 0.013). The findings suggest that college students with higher loneliness are more likely to have an evening-type sleep pattern, which exacerbates depressive symptoms. This study emphasizes the role of sleep-wake preference as a potential target for interventions to alleviate the effects of loneliness on adolescent depression, contributing to mental health prevention and treatment strategies.

β-Sitosterol (BS) is a phytosterol that may contribute to circadian and metabolic regulation through multiple predicted mechanisms. Using network pharmacology, gene expression profiling, and microbiome analysis, this study suggests that BS could interact with nuclear receptors (PPARγ, PPARα, RORα, RORγ) and potentially influence CLOCK:BMAL1 transcriptional rhythms in peripheral tissues. BS was also predicted to be associated with PER2-related feedback and the synchronization of gluconeogenic and lipogenic pathways with the light-dark cycle. In addition, computational and preclinical evidence indicates that BS may influence the gut microbiome, supporting short-chain fatty acid-producing bacteria, intestinal barrier integrity, and inflammatory balance. Limited preclinical findings further suggest a potential role for BS in mitigating circadian misalignment and insulin resistance, with possible implications for lipid homeostasis. Future clinical studies are warranted to investigate BS supplementation across different chronotypes and dietary conditions in order to evaluate its chronotherapeutic potential. While the findings are promising, they remain preliminary, and human validation is essential to determine dosing strategies and therapeutic relevance. This study, therefore, highlights BS as a candidate compound with potential relevance to circadian disruptions and metabolic disorders, pending further experimental confirmation.

Shift work, particularly night shifts, disrupts circadian rhythms and contributes to various adverse health outcomes. However, the degree of individual adaptability varies considerably, suggesting complex interactions between genetic factors, such as chronotype, and shift work exposure. To explore these interactions, we conducted a bidirectional Mendelian randomization (MR) analysis using genome-wide association study (GWAS) data from European populations. We examined causal associations between chronotype and shift work patterns (limited, intermittent, regular). A significant inverse causal effect was identified for intermittent shift work influencing morning chronotype (IVW: β =-0.0032, SE = 0.0013, p = 0.0114; weighted median: β = -0.0041, SE = 0.0018, p = 0.0213). This suggests that intermittent shift work may impact circadian preferences genetically linked to chronotype. Conversely, genetic predisposition toward morningness exhibited a notable but statistically non-significant inverse relationship with regular shift work. Our findings highlight that shift work and chronotype interact bidirectionally, potentially via circadian disruption and melatonin dysregulation. These insights could inform targeted health protection strategies for shift workers. Further studies should confirm these genetic interactions across diverse populations and clarify the underlying chronobiological mechanisms to enhance occupational health policies.

Modern lifestyles increasingly involve indoor activities, which entails considerations for ensuring sufficient light exposure for circadian entrainment and overall well-being. At higher latitudes, where daylight hours are limited in winter, environmental factors such as snow cover may enhance light exposure through its high reflectance. This study investigates the potential effects of snow cover on human biology and behavior in an urban population in Uppsala (59.9° North), Sweden between December and February. Forty-five individuals were monitored for 1 week when there was snow cover and another week without snow cover by using actigraphy, diaries, and collection of morning saliva melatonin samples. Our findings suggest that indoor dwellers at northern latitudes struggle to obtain adequate natural light exposure to sustain mood and alertness during December and January. However, snow cover increases morning light exposure, lowers melatonin levels, and enhances alertness and activity throughout the day. On the other hand, snow cover had minimal influence on sleep-wake cycles, sleep quality, and daytime mood ratings.

Light pollution has become a potential health risk factor worldwide. It exerts its effect by disrupting the circadian rhythms, which is linked to adverse health outcomes, including mood disturbances. Caffeine can influence alertness and sleep patterns, while probiotics may affect circadian regulation through the gut-brain axis. Consequently, this study aimed to investigate the potential role of caffeine (30 mg/kg) and probiotics (1 billion colony forming units (CFUs) per day) in alleviating biochemical alterations associated with depression following constant light exposure. Neurotransmitters, glutathione (GSH), malondialdehyde (MDA), and melatonin (MEL) were estimated in the cerebral cortex and the hypothalamus. Hormonal levels of MEL and corticosterone (CORT) were measured in serum samples. LL exposure reduced serotonin (5-HT) levels. It also induced alteration in MEL and CORT rhythmicity. However, caffeine enhanced 5-HT and MEL content and modulated the temporal profile of MEL. Probiotics restored corticosterone and melatonin level to a temporal pattern like controls. Additionally, both treatments reduced MDA levels and enhanced GSH content. Coadministration of caffeine and probiotics reduced 5-HT levels. In conclusion, caffeine and probiotics could modulate biochemical alterations caused by constant light exposure, which is known to disrupt circadian rhythm in rodents, making them apropriate antidepressants.

The present study aimed to examine whether and how perceived stress mediates the association between chronotype and eating disorder symptoms (ED symptoms), using both cross-sectional and three-wave longitudinal data. A total of 7,892 college students completed three online surveys over one year: 17-29 October 2023 (Time 1, T1),15-24 April 2024 (Time 2, T2), and 16-29 October 2024 (Time 3, T3). Participants completed the reduced version of the Morningness-Eveningness Questionnaire, the 10-item Perceived Stress Scale, the short form of the Eating Disorder Examination Questionnaire, the three items in the Youth Self-Rating Insomnia Scale, and a self-developed demographic questionnaire. Cross-sectional analyses showed that T1 perceived stress partially mediated the relationship between T1 chronotype and T1 ED symptoms, after controlling for demographics and T1 insomnia symptoms. Prospective analyses indicated that T1 chronotype predicted T3 ED symptoms through T2 perceived stress, after controlling for demographics, T1 insomnia symptoms, T1 perceived stress, and T1 ED symptoms. This study highlights perceived stress as a mediator linking chronotype to ED symptoms, suggesting that early identification of evening chronotype and stress-reduction interventions may help prevent ED symptoms in college students.

We aimed to examine the effects of main and side dishes at given at different time on metabolic parameters in older adults. This randomized controlled trial included, conducted June through October 2023, 43 older adults, aged 65 years and older, who were randomly divided into four groups: control (n = 8), morning (n = 12, 0700 h to 0900 h), lunch (n = 11, 1100 to 1300 h), and dinner (n = 12, 1700 to 1900 h). The participants in the control group maintained their usual dietary habits for 12 weeks. The morning, lunch, and dinner groups were each asked to consume the test meal, consisting of one main and four side dishes, once a day at a specific time for 12 consecutive weeks. Blood parameters and body composition were evaluated in the fasting state before and after the intervention. The HbA1c levels after the intervention in the morning and dinner groups were significantly lower than those at baseline (morning, p = 0.031; dinner, p = 0.016). Additionally, the body weight (BW) and BMIs after the intervention in the dinner group were significantly lower than those at baseline (BW, p = 0.002; BMI, p = 0.001). These findings indicate that the timing of main and side dishes intake may influence changes in glucose tolerance and BMI without decreasing nutritional intake.

This study examined the role of biological rhythms and sleep quality on the impact of depression on functionality in bipolar disorder (BD) and compared these factors between euthymic bipolar patients and healthy controls. Ninety-eight patients with BD were included in the study and recategorized as euthymic or depressive based on their Hamilton Depression Rating Scale scores, along with ninety-six healthy controls. Biological rhythms, functionality, and sleep quality were evaluated utilizing the Biological Rhythms Assessment in Neuropsychiatry, Functioning Assessment Short Test, and Pittsburgh Sleep Quality Index. Biological rhythms and sleep were more disrupted in bipolar depression, with no differences between euthymic patients and controls. Positive correlations were found among depression, functionality, sleep quality, and biological rhythms. Mediation analysis revealed that biological rhythm disturbances partially mediate the link between depression and functionality, while sleep quality does not. Interventions addressing both depression and biological rhythms may improve functionality in BD.

Circadian rhythm of melatonin secretion disturbance is common in patients in the intensive care unit (ICU) and may contribute to poor patient prognoses. The aim of this study was to explore the melatonin secretion rhythm in critically ill patients and to identify factors influencing the melatonin secretion rhythm. This was a prospective cohort study conducted in the surgical ICU of a tertiary hospital in Shanghai, China, between February 2022 and December 2022. Patients were enrolled if they were conscious, > 18years, had an expected ICU stay longer than 24 h, and were postoperative. Patient observations started on the first day of admission. ICU light and noise level, baseline characteristics, average night-time interruptions, pain level, use of analgesics and sedation, feeding, duration of mechanical ventilation, leukocyte and procalcitonin (PCT) level, surgical procedures and disease information were observed. We defined melatonin rhythmicity by calculating melatonin acrophase and amplitude. Serum melatonin was collected at 3:00, 8:00, and 16:00 on the first three days after admission. There were 190 ICU patients included in this study. The melatonin acrophase was abnormal in 100 (52.6%) patients. Use of analgesics (p = 0.002) and average night-time interruptions (p = 0.011) were independently related to the melatonin acrophase. Melatonin amplitude was associated with age and average night-time interruptions (p = 0.018 and p = 0.048, respectively). Clinical staff should routinely assess patients' pain levels using validated assessment tools and implement a combination of non-pharmacological and pharmacological pain control interventions. To optimize the ICU environment at night, non-urgent medical procedures should be limited to only those necessary. These approaches may help ICU patients maintain their circadian rhythm and potentially improve their overall recovery.