Chronobiology International最新文献

Circadian rhythms regulate vital biological processes, including the sleep-wake cycle, and their disruption is associated with adverse health outcomes. This study evaluated circadian misalignment using the Composite Phase Deviation (CPD) derived from 14-day actigraphy and examined its associations with sleep regularity, light exposure, and circadian timing in college students. Forty-six students (70% male) wore wrist actigraphs continuously for two weeks and completed questionnaires (PSQI, MCTQ and MEQ). Chronotype was classified using actigraphy-derived corrected mid-sleep time on free days (aMSFsc), with participants categorized as morning (earliest 25%), intermediate, or evening (latest 25%). Higher CPD was associated with later rest onset (sL5, p < 0.001), lower interdaily stability (IS, p = 0.0016), and lower Sleep Regularity Index (SRI, p < 0.001). aMSFsc was also positively associated with worse sleep quality (PSQI, p = 0.047). Group comparisons showed that evening types exhibited higher CPD than intermediate and morning types and lower SRI than morning types. No group differences were observed for the Light Regularity Index (LRI), although CPD was negatively associated with LRI at lower light thresholds. These findings indicate that CPD is a robust marker of circadian disruption and suggest that evening chronotype students experience greater misalignment and sleep irregularity.

Daytime napping is a common compensatory behavior among university students experiencing irregular nocturnal sleep and heightened stress. We examined the associations between napping behavior, perceived stress, sleep quality, and daytime sleepiness in 757 undergraduate students (≥18 y) who completed an online questionnaire including sociodemographic data, the PSS-14, PSQI, and ESS. Chi-square, MANOVA, regression analyses and K-means clustering were applied (α = 5%). Women represented 68% of the sample and reported higher stress and daytime sleepiness and were more likely to nap (χ² = 11.991; p = 0.007). Higher proportion of women reported stress management as reason to nap (χ² = 8.84; p = 0.002). The frequency of napping was predicted by sex (OR = 0.65; CI = 0.48-0.87), PSS-14 (OR = 0.98; CI = 0.96-0.99), and Epworth sleepiness scores (OR = 1.12; CI = 1.09-1.16), while napping duration was predicted by age, Epworth sleepiness, PSQI sleep efficiency, and PSQI sleep disturbance scores (R2 = 0.03; p = 0.001). Three clusters emerged: Sleep disturbances (long sleep latency, higher stress, poorer sleep quality); Shorter naps (brief naps, better sleep quality, lower stress); and More naps (younger students with frequent naps and higher sleepiness). Despite limitations related to self-reported measures, online sampling, and the overrepresentation of students from health-related programs, our findings highlight the multidimensional role of napping in the regulation of stress and sleep.

This study compared screen time, circadian rhythm patterns, and sleep quality in adults diagnosed with attention-deficit/hyperactivity disorder (ADHD) and healthy controls, and examined the associations among these parameters. The sample included 100 adults with ADHD and 100 healthy controls. Participants were assessed using a sociodemographic data form, the Diagnostic Interview for ADHD in Adults (DIVA 2.0), the Structured Clinical Interview for DSM-5 Disorders (SCID-5-CV), the Adult ADHD Self-Report Scale (ASRS), the Biological Rhythm Interview of Assessment in Neuropsychiatry (BRIAN), the Pittsburgh Sleep Quality Index (PSQI), and the Screen Exposure Questionnaire. All instruments except the DIVA 2.0 were administered to controls. Adults with ADHD reported significantly longer total daily screen time than controls (p < 0.001) and exhibited higher ASRS, BRIAN, and PSQI scores (all p < 0.001) In both groups, screen time was positively correlated with BRIAN and PSQI scores. Hierarchical regression analysis indicated that biological rhythm disruption (BRIAN scores) was a stronger predictor of poor sleep quality (PSQI scores) than ADHD symptom severity or screen time (p < 0.001)). Overall, adults with ADHD demonstrated greater screen exposure, more disrupted circadian rhythms, and poorer sleep quality compared to controls. Across the full sample, biological rhythm disruption emerged as the most robust predictor of impaired sleep, underscoring its potential clinical relevance for addressing sleep disturbances in adults with ADHD.

The prevalence of night shifts is extensive in hospital settings, particularly among nursing staff. The increasing importance of night shift work in meeting the demands of modern social care services underscores the urgent need for research into the impact of these schedules on nurses' health. This study aimed to examine the relationship between night shifts and the physical and mental well-being of nurses. Data were collected through questionnaires to obtain general demographic information and responses to the Chinese Psychosomatic Health Scale (CPSHS). The data were initially entered into Excel 2018 for verification of accuracy before being analyzed using IBM SPSS 26.0 software. The findings indicated that nurses engaged in night shift work exhibited a higher susceptibility to symptoms associated with the digestive system, reproductive endocrine system, depression, and anxiety compared to their day shift counterparts. Furthermore, a significant correlation was observed between the frequency of night shifts and increased symptom scores for digestive issues and depression. Specifically, nurses who engaged in night shifts exceeding eight instances per month demonstrated significantly higher scores in comparison to those working night shifts between five to eight times per month or fewer than four times per month. A prominent finding from the data analysis revealed that nurses undertaking night shifts more than eight times monthly exhibited a markedly higher incidence of somatic symptom disorder. The study implies that the engagement in night shift work is correlated with the physical and mental health of nurses, with the frequency of night shifts exceeding eight times per month identified as a risk factor for physical disorders among this population.

Sleep quality plays a critical role in maintaining both mental and physical health. Circadian rhythm and sleep disorders involve disruptions in the alignment between internal biological rhythms and environmental or social cues. This study aims to investigate the relationship between circadian rhythm/sleep disturbances and neurodegenerative markers in shift-working healthcare professionals. This study was conducted at Harran University Medical Faculty Hospital and included 30 night-shift healthcare workers (subject group) and 29 daytime workers (control group). Data were collected via a 25-item questionnaire on sociodemographic characteristics and work conditions, administered through face-to-face interviews. Participants also completed the Pittsburgh Sleep Quality Index (PSQI) and the Morningness-Eveningness Questionnaire (MEQ). Single morning blood samples were analyzed for neurodegenerative biomarkers (a calcium-binding protein called S100B and neuron-specific enolase, NSE), and melatonin levels were assessed from a single morning blood plasma sample. Between-group comparisons were made for questionnaire scores and biomarker levels. In the subject group, pre- and post-shift biomarker levels were also compared. The relationship between sleep quality and biomarker levels was examined. The subject group included 14 females (46.7%) and 16 males (53.3%); the control group included 15 females (51.7%) and 14 males (48.3%). The median duration of shift work was 12 h (range: 8-24). Compared to the control group, the shift workers had significantly higher PSQI scores (p = 0.002), lower MEQ scores (p = 0.003), elevated S100B levels (p = 0.003), and reduced melatonin levels (p = 0.037). Within the subject group, NSE levels were significantly higher after the shift compared to pre-shift values (p = 0.010). This study suggests that post-shift insomnia in night-shift healthcare workers is associated with elevated NSE levels, while chronic shift work is linked to increased S100B and decreased melatonin. These findings support a potential association between circadian rhythm/sleep disturbances and neurodegenerative markers.

Working memory (WM) is a cognitive system comprising multiple components, including simultaneous storage and processing of information, updating mental representations, and binding elements into coherent structures. While various studies investigated whether WM performance varies throughout the day, their findings are inconsistent. These discrepancies have been partly attributed to methodological differences, such as variations in participant chronotypes and experimental protocols. Some evidence suggested that WM components may exhibit independent diurnal variations and thus may also contribute to these inconsistent findings. Considering this, we examined whether tasks targeting distinct WM dimensions present independent diurnal fluctuations. Participants completed complex spans, updating, and binding tasks at different time-of-day (ToD): morning, midday, afternoon, and evening. A composite score was also computed to evaluate ToD effects on general WM performance. Our findings indicated that not all aspects of WM are equally affected by ToD: tasks involving simultaneous processing and storage, particularly within the visuospatial domain, showed greater diurnal variability than updating and binding tasks. Composite RTs were faster in the morning. These findings imply that task selection could have contributed to the mixed results in prior research. Future investigations should consider using multiple paradigms targeting diverse WM dimensions to better understand how ToD influences WM performance.

As the global burden of chronic kidney disease (CKD) continues to rise, it is important to identify factors that may support preservation of kidney function with age. Circadian rhythmicity declines with age, and evidence suggests that circadian rhythms influence renal physiology, yet their role in long-term kidney health remains underexplored. We tested the hypothesis that lower circadian rhythmicity would be associated with an elevated risk of kidney function decline. About 1315 older adults participating in the Rush Memory and Aging Project, a prospective community-based cohort study of the chronic conditions of aging, were studied. The median age of participants was 81.5 years [IQR: 71.8-91.2], 76.3% were female, and 93.7% identified as Caucasian. The stability of the circadian activity rhythm was quantified from up to 10 consecutive days of wrist activity using interdaily stability (IS) metric. Lower baseline IS was associated with lower eGFR (estimate = -1.9 ml/min/1.73 m² per 1SD lower IS, SE 0.4, p = 5.0 × 10^-6). Among those without baseline CKD (eGFR < 60 ml/min/1.73 m²), lower IS was associated with a ~ 25% higher future risk of developing CKD (HR 1.26, 95% CI 1.11-1.43) over a 5-years period, approaching the increased hazard associated with diabetes (HR 1.37). Effects were independent of known CKD risk factors including age, sex, obesity, hypertension, and diabetes, as well as multiple measures of sleep quality. Reduced circadian rhythmicity may therefore represent a novel modifiable risk factor for age-related decline in kidney function and CKD.

Modern societal factors frequently impede the attainment of good sleep quality by many healthy adults. We investigated the chronotype-specific predictors of changes in subjective sleep quality following the relaxation of social time pressure during COVID-19 pandemic social restrictions in Japan. One thousand two hundred and fifty-two Japanese participants were surveyed during the initial COVID-19 social restrictions. Logistic regression analyses were used to assess changes under modified social time pressure in sleep quality by chronotype group (early, intermediate, or late) from changes in patterns of daily behaviors. During social restrictions, subjective sleep quality deteriorated with delays in sleep timing across all chronotypes. Early and intermediate chronotypes' reduction in sleep quality was associated with decreased sleep duration, whereas improved subjective sleep quality was associated with increased sleep duration and minimal sleep timing delay in the early and intermediate chronotypes. In late chronotypes, improved sleep quality was also associated with longer outdoor light exposure. These findings indicate that the determinants of changes in subjective sleep quality under modified social time pressure are at least partially chronotype-specific. Maintaining sleep timing may universally enhance subjective sleep quality during perturbations of social schedules. Moreover, in late chronotypes, the exposure to daylight may improve sleep quality, regardless of changes in sleep behaviors. These insights may contribute to the development of effective strategies for promoting better sleep quality in modern societies where insufficient sleep is becoming increasingly widespread.

Recent studies have linked nighttime eating to increased body weight and metabolic risk, but evidence among adolescents remains limited. To assess the association between late-eating patterns and overweight among adolescents. This cross-sectional study used data from 7,377 Brazilian adolescents (10-19 y) from the 2008-2009 Family Budgets Survey to examine associations between late-eating patterns and overweight. Chrononutrition variables - timing of the first and last meal, eating duration, fasting duration, caloric midpoint, and eating midpoint - were estimated from two-day food diaries and categorized into tertiles. Weight status was determined by BMI-for-age z-scores. Multiple regressions models assessed associations between meal timing and overweight. Adolescents in the highest third tertile of eating duration had greater odds of excess weight (OR = 1.2, 95% CI 1.0-1.5, p = 0.04) while those in the middle tertile of night-fasting had lower odds (OR = 0.7, 95% CI 0.6-0.9, p = 0.02). Consuming a higher proportion of calories after 20:00 h was also associated with overweight (OR = 1.3, 95% CI 1.0-1.6, p = 0.03). Later timing of the last meal, caloric midpoint and longer eating duration were linked to higher total energy intake (p < 0.005). In conclusion, late eating is associated with excess weight and increased caloric intake among adolescents, underscoring meal timing as a modifiable target for obesity prevention.