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Objectives. Associations between shift-work, musculoskeletal symptoms and absenteeism are poorly investigated in the manufacturing industry. This study aimed to investigate associations between working schedule, musculoskeletal symptoms and days of absenteeism among pulp and paper industry workers. Methods. Musculoskeletal symptoms of 904 workers were assessed through the Nordic Musculoskeletal Questionnaire. χ2 tests assessed associations between being a day-worker or shift-worker, the prevalence of musculoskeletal symptoms and days of absenteeism. Results. A significant association was found between working schedule and symptoms in the lower back in the last 12 months, with shift-workers presenting higher prevalence than day-workers (p = 0.022). Significant associations were also found between days of absenteeism and symptoms in the shoulders (p = 0.002), which mostly led to absenteeism of 100–365 days; elbows (p < 0.001), wrists/hands (p = 0.045) and ankles/feet (p = 0.042), which produced absenteeism mostly of 25–99 days; and dorsal region (p = 0.001), which mainly led to absenteeism of 10–24 days. No associations were found between working schedule and days of absenteeism (p = 0.265). Conclusion. Shift-work is associated with increased prevalence of lower back symptoms, but seems not to influence days of absenteeism. Shoulders seem to be the region leading to higher days of absenteeism, followed by elbows, wrists/hands, ankles/feet and the dorsal region. [ABSTRACT FROM AUTHOR]

Background: Missed care is defined as the omission or delay of necessary patient care and is internationally reported by nurses as a significant safety risk. Nurses working at night also report high levels of occupational fatigue that, coupled with inadequate staffing and practice environment support, may impede a nurse's ability to carry out the nursing process and lead to more missed care. Objective: The study's objective was to examine the interrelationships among organizational and nurse characteristics, occupational fatigue, and missed care among nurses working at night. Methods: A cross-sectional design was used. Participants included registered nurses (RNs) who worked at night in New Jersey acute care hospitals. Multiple linear regression and simple moderation analyses were performed to examine the associations. Results: Nurses reported missing necessary care at night. Unsupportive practice environments, high RN workloads, high patient–RN ratios, high chronic fatigue levels, and low intershift recovery were individually associated with missed care at night. High patient-to-RN ratios and chronic fatigue were independently associated with missed care. However, patient-to-registered-staffing levels had the most considerable effect on missed care at night. Nurses' years of experience and the number of hours of sleep between shifts were significant moderators of the relationship between occupational fatigue states and missed care. Discussion: This study is the first to examine the interrelationship between occupational fatigue levels, organizational and nurse characteristics, and missed care at night. There is an urgent need to implement strategies in hospital organizations that foster work schedules and adequate staffing patterns that lessen nurses' occupational fatigue levels to ensure our workforce's and patients' safety. [ABSTRACT FROM AUTHOR]

That disruptions of the body's internal clockwork can lead to negative health consequences, including cancer, is a plausible hypothesis. Yet, despite strong mechanistic and animal support, the International Agency for Research on Cancer (IARC) experts considered epidemiological evidence as limited regarding the carcinogenicity of "shift-work involving circadian disruption" (2007) and "night shift work" (2019). We use directed acyclic graphs (DAGs) to outline a concept of circadian causes that discloses challenges when choosing appropriate exposure variables. On this basis, we propose to move beyond shift-work alone as a direct cause of disease. Instead, quantifying chronodisruption as individual doses can lead to interpretable circadian epidemiology. The hypothesis is that doses of chronodisruption cause disrupted circadian organisation by leading to desynchronization of circadian rhythms. Chronodisruption can be conceptualized as the split physiological nexus of internal and external times. Biological (or internal) night – an individual's intrinsically favoured sleep time window – could be the backbone of circadian epidemiology. In practice, individual doses that cause disrupted circadian organisation are derived from the intersection of time intervals of being awake and an individual's biological night. After numerous studies counted work shifts, chronobiology may now advance circadian epidemiology with more specific dose estimation – albeit with greater challenges in measurement (time-dependent individual data) and analysis (time-dependent confounding). [ABSTRACT FROM AUTHOR]

Abstract Background There exists a great diversity of schedules concerning the way shift work is organized and implemented with ample agreement regarding recommendable features of a shift system. In order to adapt the shift schedule of a metropolitan police department to current recommendations, a remodelled shift schedule was introduced in 2015. The aim of this study was to evaluate the potential associations between the remodelled shift schedule and work ability, quality of life and self-rated health after one and five years. Methods A controlled before-and- after study was conducted during the piloting phase (2015–2016) as well as a 5-year follow-up using paper questionnaires. Outcome parameters included work ability, quality of life and self-rated health. Results Work ability, quality of life and self-rated health improved after the first year of the newly implemented shift schedule among police officers working in the piloting police stations compared to those working according to the former schedule. In 5-year follow-up differences between indicators diminished. Conclusions The implementation of a remodelled shift schedule including more 12-h shifts accompanied by more days off and a coherent weekend off duty was not associated with detrimental effects to work ability, quality of life or self-reported health among police officers.

This systematic review focuses on factors associated with occupational road crashes among professional drivers of commercial vehicles, e.g. trucks, buses and taxis. PubMed, MEDLINE and Google Scholar were searched, and quality assessment followed guidelines developed by the British Sociological Association medical sociological group. Sixty-six cross-sectional studies and one cohort study were included, of which 18, 45 and 3 studies were categorised as high-, moderate- and low-quality studies, respectively. Twenty-seven significant risk factors for road crashes were divided into six domains: (1) organisational, (2) individual driver characteristics, (3) qualifications, (4) driver conditions, (5) driving behaviour, and (6) external. The most frequently investigated factors were age (individual driver characteristics domain), sleepiness and substance use (driver conditions), driving duration and time of driving (organisational). More recently studied risk factors were management support (organisational), years of experience (qualifications), health parameters (driver conditions), vehicle speed and distracting activities, e.g. use of phone or navigation tools while driving (driving behaviour). The review identified overall risk factor domains and occupation-specific risk factors suitable for targeting and prioritising organisational preventive safety efforts. To obtain a more in-depth understanding of the antecedents of road crashes, future prospective studies are encouraged that evaluate preventive strategies for occupational road crashes. [ABSTRACT FROM AUTHOR]

Exposure of mice to a 24 h light:dark:light:dark (LDLD) cycle with dimly illuminated nights induces the circadian timing system to program two intervals of activity and two intervals of rest per 24 h cycle and subsequently allows entrainment to a variety of extraordinary light regimens including 30 h LDLD cycles. Little is known about critical lighting requirements to induce and maintain this non-standard entrainment pattern, termed "bifurcation," and to enhance the range of apparent entrainment. The current study determined the necessary duration of the photophase for animals to bifurcate and assessed whether requirements for maintenance differed from those for induction. An objective index of bifurcated entrainment varied with length of the photophase over 4-10 h durations, with highest values at 8 h. To assess photic requirements for the maintenance of bifurcation, mice from each group were subsequently exposed to the LDLD cycle with 4 h photophases. While insufficient to induce bifurcation, this photoperiod maintained bifurcation in mice transferred from inductive LDLD cycles. Entrainment to 30 h LDLD cycles also varied with photoperiod duration. These studies characterize non-invasive tools that reveal latent flexibility in the circadian control of rest/activity cycles with important translational potential for addressing needs of human shift-workers.

Background: There exists a great diversity of schedules concerning the way shift work is organized and implemented with ample agreement regarding recommendable features of a shift system. In order to adapt the shift schedule of a metropolitan police department to current recommendations, a remodelled shift schedule was introduced in 2015. The aim of this study was to evaluate the potential associations between the remodelled shift schedule and work ability, quality of life and self-rated health after one and five years.Methods: A controlled before-and- after study was conducted during the piloting phase (2015-2016) as well as a 5-year follow-up using paper questionnaires. Outcome parameters included work ability, quality of life and self-rated health.Results: Work ability, quality of life and self-rated health improved after the first year of the newly implemented shift schedule among police officers working in the piloting police stations compared to those working according to the former schedule. In 5-year follow-up differences between indicators diminished.Conclusions: The implementation of a remodelled shift schedule including more 12-h shifts accompanied by more days off and a coherent weekend off duty was not associated with detrimental effects to work ability, quality of life or self-reported health among police officers. [ABSTRACT FROM AUTHOR]

Shift work (work outside of standard daylight hours) is common throughout the Western world. However, there are notable health consequences to shift work, including increased prevalence of mental health and sleep disorders in shift worker populations. Therefore, the health and wellbeing of shift workers is a public health concern that needs to be addressed. Here we investigate the effects of two separate light induced shift work-like patterns on male and female mouse behaviour (anxiety-like, exploration, marble burying, startle reflex and circadian rhythms). After 6 weeks of shift-like disruptions patterns, animals displayed no behavioral differences in exploration, marble burying and startle reflex. Interestingly however, we identified sex specific and disruption specific effects in light aversion and wheel running activities. Notably, analysis of the activity patterns of animals in disruptive conditions demonstrated that they maintained a degree of rhythmicity through the disruption period, which may explain the lack of behavioral differences in most behavioral tests.

Prolonged exposure to chronic sleep restriction (CSR) and shiftwork are both associated with incident hypertension and cardiovascular disease. We hypothesized that the combination of CSR and shiftwork’s rotating sleep schedule (causing recurrent circadian disruption, RCD) would increase blood pressure, renal sodium retention, potassium excretion, and aldosterone excretion. Seventeen healthy participants were studied during a 32-day inpatient protocol that included 20-h “days” with associated scheduled sleep/wake and eating behaviors. Participants were randomly assigned to restricted (1:3.3 sleep:wake, CSR group) or standard (1:2 sleep:wake, Control group) ratios of sleep:wake duration. Systolic blood pressure during circadian misalignment was ∼6% higher in CSR conditions. Renal sodium and potassium excretion showed robust circadian patterns; potassium excretion also displayed some influence of the scheduled behaviors (sleep/wake, fasting during sleep so made parallel fasting/feeding). In contrast, the timing of renal aldosterone excretion was affected predominately by scheduled behaviors. Per 20-h “day,” total sodium excretion increased, and total potassium excretion decreased during RCD without a change in total aldosterone excretion. Lastly, a reduced total renal sodium excretion was found despite constant oral sodium consumption and total aldosterone excretion, suggesting a positive total body sodium balance independent of aldosterone excretion. These findings may provide mechanistic insight into the observed adverse cardiovascular and renal effects of shiftwork. [ABSTRACT FROM AUTHOR]

Prolonged exposure to chronic sleep restriction (CSR) and shiftwork are both associated with incident hypertension and cardiovascular disease. We hypothesized that the combination of CSR and shiftwork’s rotating sleep schedule (causing recurrent circadian disruption, RCD) would increase blood pressure, renal sodium retention, potassium excretion, and aldosterone excretion. Seventeen healthy participants were studied during a 32-day inpatient protocol that included 20-h “days” with associated scheduled sleep/wake and eating behaviors. Participants were randomly assigned to restricted (1:3.3 sleep:wake, CSR group) or standard (1:2 sleep:wake, Control group) ratios of sleep:wake duration. Systolic blood pressure during circadian misalignment was ∼6% higher in CSR conditions. Renal sodium and potassium excretion showed robust circadian patterns; potassium excretion also displayed some influence of the scheduled behaviors (sleep/wake, fasting during sleep so made parallel fasting/feeding). In contrast, the timing of renal aldosterone excretion was affected predominately by scheduled behaviors. Per 20-h “day,” total sodium excretion increased, and total potassium excretion decreased during RCD without a change in total aldosterone excretion. Lastly, a reduced total renal sodium excretion was found despite constant oral sodium consumption and total aldosterone excretion, suggesting a positive total body sodium balance independent of aldosterone excretion. These findings may provide mechanistic insight into the observed adverse cardiovascular and renal effects of shiftwork.

Abstract Background The International Agency for Research on Cancer (IARC) has classified shift work as a possible human carcinogen. The results of systematic on this topic is contradictory. This systematic review and meta-analysis, therefore, aimed to update the current evidence regarding the relationship between night-shift work duration and breast cancer risk. Methods PubMed, Web of Science, and Scopus as well as reference list of included studies were searched until December 19, 2020. Observational case–control or cohort studies investigating the relationship between the duration of night-shift work and breast cancer in women were included, which all quantified night-shift work exposure. All statistical analyses were done by Stata version 11.2. Results Our literature search was resulted in retrieval of 4854 publications from which 26 eligible studies with 1,313,348 participants were included in the meta-analyses. The pooled relative risk (RR) and 95% confidence intervals (CIs) of breast cancer for short-term night-shift workers (

Insomnia remains the most prevalent sleep disorder worldwide, and its pathophysiology suggests an interface with circadian rhythm sleep-wake disorders (CRSWDs). Some epidemiological studies have linked insomnia and circadian misalignment with adverse cardiometabolic outcomes, but the mechanisms underlying this relationship are still unclear. The autonomic nervous system (ANS) has been pointed out as a crucial/key mediator that triggers cardiometabolic risk. Therefore, a critical review of the literature focused on the past ten years was conducted to highlight the relationship between insomnia, circadian misalignment and cardiometabolic risk, with particular emphasis on the influence of the ANS. Shift work, as a model of circadian misalignment, was shown to increase both cardiovascular and metabolic risk and so may integrate a proof of concept on this link. Furthermore, there is good evidence from previous studies supporting that cardiac autonomic dysfunction is indeed a possible mechanism that potentiates cardiometabolic risk in insomniacs and individuals with a misalignment of the circadian timing system (e.g., shift workers), via changes in autonomic variables. Further research is however required in order to definitively establish this interactive relationship.

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Shift-work can alter the nurses' lifestyle behaviors, which negatively influence health. This study is purposed to assess the relationship between shift-work and selected lifestyle behaviors including, dietary habits, physical activity, and nicotine dependence among Jordanian nurses who work at the emergency department. A cross-sectional, descriptive correlational design was used. A total of 275 Jordanian nurses from the emergency department of Jordanian hospitals participated in the questionnaire. The results showed that 50.2% of the nurses suffered from poor dietary habits, 81.8% of them were physically inactive, and 65.1% had nicotine dependence. There was a positive correlation between shift-work, dietary habits, physical activity, and nicotine dependence. Therefore, the effects of shift-work should be considered when planning and developing interventional programs to enhance nurses' health and promote healthy behaviors among nurses workforce during shift-work. [ABSTRACT FROM AUTHOR]

Sleep is essential for preventing fatigue in occupations that require sustained vigilance. We conducted a scoping review to synthesize knowledge about sleep, fatigue, and performance in pilots, commercial truck drivers, and astronauts. We found 28 studies where researchers objectively or subjectively measured sleep, fatigue, and performance. The research included laboratory-based (simulator) and field-based studies (i.e. real-world missions and a variety of shift-work schedules). Most researchers used actigraphy to measure sleep, and they found that ~6 hrs of sleep was common. The research also demonstrated how sleep duration and quality were negatively affected by schedule irregularity, early-morning start times, and high-risk missions (e.g. extravehicular activities in space). Collectively, the data demonstrated how shorter sleep durations, short off-duty time, and early-morning start times were associated with slower reaction times, more lapses in attention, and premature responses on psychomotor vigilance tests. Considering that few studies included polysomnography and circadian rhythm biomarkers, there remains limited knowledge about the effects of sleep microstructure and circadian rhythm alterations on performance abilities in these occupations. Future neurobiological and mechanistic discoveries will be important for enhancing vigilance, health, and safety for people working in the skies, on the roads, and in space. [ABSTRACT FROM AUTHOR]

Summary: Cardiovascular diseases cause >4 million deaths each year in Europe alone. Preventive approaches that do not only consider individual risk factors but their interaction, such as the Systematic COronary Risk Evaluation (SCORE), are recommended by European guidelines. Increased cardiovascular risk is associated with shift‐work, surely interacting with the concurrent conditions: disruption of sleep, unhealthy behaviours, and circadian misalignment. Social jetlag (SJL) has been proposed as a way to quantify circadian misalignment. We therefore investigated the association between SJL and cardiovascular health in a cross‐sectional observational study involving blue‐collar workers, who either worked permanent morning, evening, or night shifts. Sociodemographic, health and productivity data were collected through questionnaires. Blood pressure and cholesterol were measured and the cardiovascular risk was estimated according to the relative risk SCORE chart. Bivariate analysis was performed according to the cardiovascular risk and the relationship between SJL and high cardiovascular risk was analysed through logistic regression. Cumulative models were performed, adjusted for various confounding factors. After 49 exclusions, the final sample comprised 301 workers (56% males; aged <40 years, 73%). Mean standard deviation (SD) SJL was 1:57 (1:38) hr (59.4% ≤2 hr). Cardiovascular risk was high in 20% of the sample. Multivariate analysis revealed SJL to be an independent risk factor for high cardiovascular risk. Each additional hour of SJL increased this risk by >30% (odds ratio 1.31, 95% confidence interval 1.02–1.68). This is the first study indicating that SJL potentially increases cardiovascular risk, and suggests that sleep and individual circadian qualities are critical in preventing negative health impacts of shift‐work. [ABSTRACT FROM AUTHOR]

The time of dim light melatonin onset (DLMO) is the gold standard for circadian phase assessment in humans, but collection of samples for DLMO is time and resource‐intensive. Numerous studies have attempted to estimate circadian phase from actigraphy data, but most of these studies have involved individuals on controlled and stable sleep‐wake schedules, with mean errors reported between 0.5 and 1 hour. We found that such algorithms are less successful in estimating DLMO in a population of college students with more irregular schedules: Mean errors in estimating the time of DLMO are approximately 1.5‐1.6 hours. We reframed the problem as a classification problem and estimated whether an individual's current phase was before or after DLMO. Using a neural network, we found high classification accuracy of about 90%, which decreased the mean error in DLMO estimation—identifying the time at which the switch in classification occurs—to approximately 1.3 hours. To test whether this classification approach was valid when activity and circadian rhythms are decoupled, we applied the same neural network to data from inpatient forced desynchrony studies in which participants are scheduled to sleep and wake at all circadian phases (rather than their habitual schedules). In participants on forced desynchrony protocols, overall classification accuracy dropped to 55%‐65% with a range of 20%‐80% for a given day; this accuracy was highly dependent upon the phase angle (ie, time) between DLMO and sleep onset, with the highest accuracy at phase angles associated with nighttime sleep. Circadian patterns in activity, therefore, should be included when developing and testing actigraphy‐based approaches to circadian phase estimation. Our novel algorithm may be a promising approach for estimating the onset of melatonin in some conditions and could be generalized to other hormones. [ABSTRACT FROM AUTHOR]

Background The aim of this study was to assess the prevalence of insomnia among the employees of a zinc smelter in Miasteczko Śląskie using the Athens Insomnia Scale . Material and Methods The examined group of plant employees and the control group were asked to fill in a questionnaire composed of the AIS and questions relating to the place and nature of their work, accidents over the last year, medications, diseases and conditions, sleep, naps and sleepiness during the day. Results The result leading to a diagnosis of insomnia as indicated by the AIS was found in significantly more instances in the test group than in the control group (29.5% vs. 8.4%). While comparing the test subgroup, which was not employed in shift-work, with the control group did not result in a statistically significant difference, slightly more respondents from the day-work test subgroup obtained the result of ≥ 8 pts. Conclusions The prevalence of insomnia assessed by means of the AIS in the group of employees of a zinc smelter is significantly higher than in the control group. Based on the AIS, the highest percentage of individuals with insomnia occurred in the subgroup employed in shift-work. Med Pr. 2019;70(5):611–6

The penetration of plug-in electric vehicles (PEVs) has greatly increased over the past few years. By using vehicle-to-grid (V2G) technology, PEVs can be used as “mobile batteries” in a microgrid. Here, we aim to coordinate the V2G dispatch with traditional energy management in a corporate energy system (CES). To do so, a two-stage robust optimization (RO) model is built with respect to uncertainties in the CES, e.g., photovoltaic (PV) power. Particularly, relationships between the working time schedule and PEVs are investigated and analyzed for the first time, and a novel PEV aggregator model, i.e., shift-working V2G, is presented. The shift-working V2G model provides beneficial characteristics, like weakened randomness and stable storage capacity. A quantitative method to evaluate the V2G capacity is then presented. An analytical solution methodology is also proposed, which can equivalently convert the robust “min-max-min” model to a single-level mixed-integer linear programming (MILP) model. Case studies are conducted for an iron and steel company in Shanghai, China, with almost 40 000 PEVs. The results show that V2G integration can significantly improve the load-tracking ability of CES and help reduce the energy cost, although the V2G cost is considered. The computational efficiency is also improved compared with the existing methods. Note to Practitioners—This article is motivated by the problem of using the battery storage capacities of plug-in electric vehicles (PEVs) in a corporate energy system (CES) such as an iron and steel plant, aiming at minimizing the energy cost. In existing studies, behaviors of PEVs (e.g., arriving or leaving time) have usually been elusive since they are directly decided by drivers, and thus, it is difficult to determine how much storage capacity PEVs can provide. However, in a CES where a shift-work regulation is implemented, employees should arrive or leave punctually during each shift, and the same is true of their PEVs. Based on this fact, PEVs within one shift could show weakened randomness and stable storage capacities. In this article, the influences of the shift-work regulation on the PEVs are fully analyzed, and the shift-working V2G provides an easy way to integrate PEVs into the CES. In practice, the shift-working V2G model can be applied to any energy system that also implements a shift-work regulation, such as a fire station. [ABSTRACT FROM AUTHOR]

Background: The International Agency for Research on Cancer (IARC) has classified shift work as a possible human carcinogen. The results of systematic on this topic is contradictory. This systematic review and meta-analysis, therefore, aimed to update the current evidence regarding the relationship between night-shift work duration and breast cancer risk.Methods: PubMed, Web of Science, and Scopus as well as reference list of included studies were searched until December 19, 2020. Observational case-control or cohort studies investigating the relationship between the duration of night-shift work and breast cancer in women were included, which all quantified night-shift work exposure. All statistical analyses were done by Stata version 11.2.Results: Our literature search was resulted in retrieval of 4854 publications from which 26 eligible studies with 1,313,348 participants were included in the meta-analyses. The pooled relative risk (RR) and 95% confidence intervals (CIs) of breast cancer for short-term night-shift workers (< 10 years) was 1.13 (95% CI 1.03-1.24, p = 0.008, I2 = 71.3%), and for long-term night-shift workers (≥ 10 years) was 1.08 (95% CI 0.99-1.17, p = 0.09, I2 = 42.2%), with moderate to substantial statistical heterogeneity observed in both analyses. The results of subgroup analysis showed that flight attendants with long overnight flights were at an elevated risk of breast cancer, but unmeasured confounders limited these results. The risk of breast cancer in case control studies, adjusted for reproductive factors and family history of breast cancer as well as studies with high quality was increased in both short term and long term night-shift workers.Conclusions: This systematic review found a positive statistical relationship between night work and breast cancer risk in short-term night-shift workers but no increase was observed in the long-term night-shift workers. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to explore the knowledge and performance of sleep hygiene among nurses with shift work schedules and examine the influence on sleep disturbance. Methods: A total of 199 shift-work nurses from a tertiary hospital were included in the study. To examine the knowledge and performance of sleep hygiene, the participants were asked to respond to a self-reported survey. To assess sleep disturbance, the General Sleep Disturbance Scale was used. Descriptive statistics and multiple linear regression were applied using the SPSS/WIN 21.0 program to analyze the data. Results: Both the knowledge and performance of sleep hygiene among nurses with shift work schedules were measured at a moderate level. Nurses’ knowledge and the performance of sleep hygiene was not significantly associated with sleep disturbance, whereas age, experience with shift-working, and perceived health status were significantly associated. Conclusion: Strategies for providing more accurate information and motivating better sleep hygiene would help to enhance sleep hygiene in nurses with shift work schedules. Further studies examining the association [ABSTRACT FROM AUTHOR]

Background: During 24‐hour on‐call shifts medical residents are exposed to diverse circumstances such as sleep deprivation and stress. Objective: Our aim is to assess the effect of 24‐hour on‐call shifts on medical residents' headache‐related disability. Methods: The Migraine Disability Assessment Scale (MIDAS), the Headache Impact Test (HIT–6), the Pittsburgh Sleep Quality Index (PSQI), and the Hospital Anxiety and Depression Scale (HADS) questionnaires were administered to medical residents who had never performed on‐call shifts at baseline and 6 months after beginning 24‐hour on‐call shifts. Scores were compared. Results: About 66 medical residents completed this study. About 21.2% (n = 14) had history of migraine, 42.4% (n = 28) had a history of tension‐type headache (TTH) and 12.1% (n = 8) had a history of both migraine and TTH. Among medical residents with migraine, the median MIDAS score was significantly higher after starting 24‐hour on‐call shifts than at a baseline (4.0 vs 8.0; Wilcoxon, P =.001), meaning that, on average, disability increased from little or no disability, to moderate disability. No difference in HIT‐6 scores was found. The median score of PSQI and HADS was higher at 6 months (PSQI: 7.0 vs 8.0; P =.003), (HADS: 5.0 vs 8.0; P <.001) for the general group. Conclusions: In medical residents with migraine, migraine‐related disability increased after starting 24‐hour on‐call shifts. We also found a worsening in depression and anxiety symptoms and self‐reported sleep quality in medical residents with and without headache history. [ABSTRACT FROM AUTHOR]

Circadian rhythms are generated by the circadian clock, a self-sustained internal timing system that exhibits 24-h rhythms in the body. In mammals, circadian rhythms are driven by a central clock located in suprachiasmatic nucleus and various peripheral clocks located in different tissues and organs of the body. Many cellular, behavioral, and physiological processes are regulated by the circadian clock in coordination with environmental cues. The process of metabolism is also under circadian regulation. Loss of synchronization between the internal clock and environmental zeitgebers results in disruption of the circadian rhythms that seriously impacts metabolic homeostasis leading to changed eating behavior, altered glucose and lipid metabolism, and weight gain. This in turn augments the risk of having various cardio-metabolic disorders such as obesity, diabetes, metabolic syndrome, and cardiovascular disease. This review sheds light on circadian rhythms and their role in metabolism with the identification of gaps in the current knowledge that remain to be explored in these fields. In this review, the molecular mechanisms underlying circadian rhythms have been elaborated first. Then, the focus has been kept on explaining the physiological significance of circadian rhythms in regulating metabolism. Finally, the implications for metabolism when these rhythms are disrupted due to genetic mutations or social and occupational needs enforced by modern lifestyle have been discussed. [ABSTRACT FROM AUTHOR]

Background: Shift-workers commonly suffer from insomnia. This study evaluates different domains of insomnia. Aim: This study was aimed to study sleep and insomnia in rotating shift-workers and compare with day-workers. Materials and Methods: This was case–control study. The sleep of rotating shift-workers is compared with day workers using Athens Insomnia Scale. Results: Rotating shift-workers had significantly higher scores on Athens insomnia scale on domains of initial, intermediate and terminal insomnia than day workers. Duration and quality of sleep and sense of well-being are lower in rotating shift-workers. Rotating shift-workers also experienced more day-time sleepiness than day workers. However, there was no difference in perceived physical and mental functioning between the two groups. Conclusion: Individuals working in rotating shifts for more than 15 days have significantly higher prevalence of insomnia than day-workers.

Epidemiological studies indicate that shift-workers have an increased risk of type 2 diabetes mellitus (T2DM). Glucose tolerance and insulin sensitivity both are dependent on the circadian timing system (i.e., the time-of-day) and fasting duration, in rodents as well as humans. Therefore, question is whether manipulation of the circadian timing system, for example by changing the timing of feeding and fasting, is a potential preventive treatment for T2DM. Time-restricted feeding (TRF) is well-known to have profound effects on various metabolic measures, including glucose metabolism. However, experiments that directly measure the effects of TRF on glucose tolerance and/or insulin sensitivity at different time points throughout the 24 h cycle are lacking. Here we show, in rats, that TRF in line with the circadian timing system (i.e., feeding during the active phase) improves glucose tolerance during intravenous glucose tolerance tests (ivGTT) in the active phase, as lower insulin levels were observed with similar levels of glucose clearance. However, this was not the case during the inactive phase in which more insulin was released but only a slightly faster glucose clearance was observed. Contrasting, TRF out of sync with the circadian timing system (i.e., feeding during the inactive phase) worsened glucose tolerance, although only marginally, likely because of adaptation to the 4 week TRF regimen. Our results show that TRF can improve glucose metabolism, but strict adherence to the time-restricted feeding period is necessary, as outside the regular eating hours glucose tolerance is worsened.

Epidemiological studies indicate that shift-workers have an increased risk of type 2 diabetes mellitus (T2DM). Glucose tolerance and insulin sensitivity both are dependent on the circadian timing system (i.e., the time-of-day) and fasting duration, in rodents as well as humans. Therefore, question is whether manipulation of the circadian timing system, for example by changing the timing of feeding and fasting, is a potential preventive treatment for T2DM. Time-restricted feeding (TRF) is well-known to have profound effects on various metabolic measures, including glucose metabolism. However, experiments that directly measure the effects of TRF on glucose tolerance and/or insulin sensitivity at different time points throughout the 24 h cycle are lacking. Here we show, in rats, that TRF in line with the circadian timing system (i.e., feeding during the active phase) improves glucose tolerance during intravenous glucose tolerance tests (ivGTT) in the active phase, as lower insulin levels were observed with similar levels of glucose clearance. However, this was not the case during the inactive phase in which more insulin was released but only a slightly faster glucose clearance was observed. Contrasting, TRF out of sync with the circadian timing system (i.e., feeding during the inactive phase) worsened glucose tolerance, although only marginally, likely because of adaptation to the 4 week TRF regimen. Our results show that TRF can improve glucose metabolism, but strict adherence to the time-restricted feeding period is necessary, as outside the regular eating hours glucose tolerance is worsened. [ABSTRACT FROM AUTHOR]

BACKGROUND: Extensive research has demonstrated that shift-work and time of day affect one's ability to maintain alertness and vigilance. Research has also sought to determine ways to increase alertness and decrease the effects of fatigue in high vigilance environments, such as air traffic control. This study was designed to assess the effectiveness of video game play as a fatigue countermeasure in air traffic controllers. METHODS: We tested 22 military air traffic controllers to ascertain whether video game play prior to time in the air traffic control room heightened their alertness during their shift. An oculometer, which is an objective measure of physiological arousal and visual alertness, was used to measure pupillary diameter, amplitude, latency, and velocity. Perceived alertness was assessed using the Stanford Sleepiness Scale. Over a 4-wk period, the air traffic controllers participated in a counterbalanced, within-subjects design study with experimental (video gaming prior to control room) and control (no video gaming prior to control) conditions. RESULTS: We used a within-subjects, repeated measures MANOVA to compare differences in physiological and perceived alertness of individuals in the two conditions. Results indicated that video game play significantly increased physiological alertness in air traffic controllers, especially pupil diameter and velocity, and this effect was sustained for at least 30 min after they stopped playing. Perceived alertness was also increased by video game play. DISCUSSION: These results indicate that video game play could be an effective fatigue countermeasure in high vigilance occupatiorvs such as air traffic control. [ABSTRACT FROM AUTHOR]

Abstract Sleep loss is one of the most common causes of accidents and errors in operational environments. Currently, no single method satisfies all of the requisite criteria of an effective system for assessing the risk of injury prior to safety being compromised. Research has concentrated towards the development of a biomarker for individualized assessment of sleepiness-related deficits in neurobehavioral alertness, with salivary alpha-amylase (sAA) recently reported as a potential biomarker during acute total sleep deprivation. The present study extends on previous research by investigating the association between sAA and neurobehavioral alertness during simulated night-shift work, during individuals are required to work at night when biological processes are strongly promoting sleep and sleep during the day when endogenous processes are promoting wakefulness. In a laboratory-controlled environment, 10 healthy non-shift working males aged 24.7 ± 5.3 years (mean ± SD) underwent four consecutive nights of simulated night-shift work. Between 17:30–04:30 h participants provided saliva samples and completed a 3 min psychomotor vigilance test (PVT-B), 40 min simulated driving task, and 3 min digit symbol substitution test (DSST). Higher sAA levels were associated with faster response speed on the PVT-B, reduced lane variability on the simulated driving task, and improved information processing speed on the DSST during the first night-shift. There were no associations between sAA levels and performance outcomes during subsequent night-shifts. Findings indicate that the usability of sAA to assess the risk of neurobehavioral deficits during shift-work operations is limited. However, the robust circadian rhythm exhibited by sAA during the protocol of circadian misalignment suggests that sAA could serve as a potential circadian marker. Highlights • Salivary alpha-amylase levels predict alertness during total sleep deprivation • Salivary alpha-amylase levels do not predict alertness during night-shift work. • Circadian rhythm of salivary alpha-amylase is robust. • Salivary levels of alpha-amylase may serve as an adjunct circadian marker [ABSTRACT FROM AUTHOR]

The circadian system drives the temporal organization of body physiology in relation to the changing daily environment. Shift-work (SW) disrupts this temporal order and is associated with the loss of homeostasis and metabolic syndrome. In a rodent model of SW based on forced activity in the rest phase for 4 weeks, we describe the occurrence of circadian desynchrony, as well as metabolic and liver dysfunction. To provide better evidence for the impact of altered timing of activity, this study explored how long it takes to recover metabolic rhythms and behavior. Rats were submitted to experimental SW for 4 weeks and then were left to recover for one week. Daily locomotor activity, food intake patterns, serum glucose and triglycerides, and the expression levels of hepatic Pparα, Srebp-1c, Pepck, Bmal1 and Per2 were assessed during the recovery period and were compared with expected data according to a control condition. SW triggered the circadian desynchronization of all of the analyzed parameters. A difference in the time required for realignment was observed among parameters. Locomotor activity achieved the expected phase on day 2, whereas the nocturnal feeding pattern was restored on the sixth recovery day. Daily rhythms of plasma glucose and triglycerides and of Pparα, Pepck and Bmal1 expression in the liver resynchronized on the seventh day, whereas Srebp-1c and Per2 persisted arrhythmic for the entire recovery week. SW does not equally affect behavior and metabolic rhythms, leading to internal desynchrony during the recovery phase. [ABSTRACT FROM AUTHOR]

In Europe, until half a century ago, shift work was used almost exclusively to provide essential services such as health, transport, communications and public safety or to facilitate particular technological processes in the steel and chemical industries. Today, following the globalization of products and services and the need for competitiveness among companies there has been a change in working hours, in order to guarantee continuous work cycles for 24 hours. The disruption of circadian rhythms related to shift and night work may favor the onset of the "shift work sleep disorder", a disease characterized by insomnia and excessive sleepiness. These alterations represent, in turn, a risk factor for other health issues, injuries, accidents, lower productivity. EU and national legislations on occupational health and safety provide for a series of protection measures of shift workers including risk assessment, information and training, health surveillance and health promotion. Moreover, occupational health promotion assumes a strategic value for companies, especially if it is linked to the reduction of additive or synergistic effects on the health of both occupational and lifestyle risks. The integration of economic sciences, life sciences and ergonomics in the organization of shift systems is an emerging need for companies. The literature provides evidence that strategic health promotion interventions in the workplace lead to a return on investment. Therefore, in the context of the future of work, the organization of shifts according to ergonomic criteria must be seen by the companies more as an opportunity than as a cost. [ABSTRACT FROM AUTHOR]

Circadian disruption (CD) was implicated in chains of cancer causation when the International Agency for Research on Cancer classified shift-work involving circadian disruption as probably carcinogenic in 2007. In the following decade, epidemiological studies into causal concepts associated with circadian disruption were inconclusive. Unappreciated complexity with an exclusive focus on shift-work, light-at-night, sleep, and melatonin in regard to circadian disruption may be accountable. With compelling non-epidemiological evidence, we posit that ubiquitous circadian disruption causes cancer and, moreover, that this is unexplored epidemiologically. This hypothesis offers a novel explanation why numerous studies in shift-workers evince inconsistent results: If circadian disruption is a ubiquitous causal phenomenon, confining assessments to the workplace, ignoring circadian disruption at play, and potential misclassification of 'who' is 'when' and 'how much' exposed to circadian disruption may disallow detecting the existence and magnitude of cancer risks. The rationale herein provides plausible explanations for previous observations and makes falsifiable predictions. [ABSTRACT FROM AUTHOR]

This paper is an approach to the impact of shift work on economic performance and size of the production series. The presented methodology has a significant impact on improving the quality of economic performance in terms of reducing the cost per unit of output in serial production. The paper is illustrated with a concrete example of the analysis and application of the methodology discussed with the software support.

Abstract Adult Nothobranchius furzeri of the MZM-04/10 strain were individually kept and subjected to a "5 + 2" shifting lighting schedule (SHIFT) for 8 weeks in order to evaluate the desynchronizing effects of a simulated human-like shift-work schedule on the functioning of the circadian system (CS). With this aim, sixteen 21-week-old N. furzeri were placed into a Morning, Night and Evening schedule (lights on from 08:00 to 16:00, 00:00 to 08:00 and 16:00 to 00:00 h, respectively) and fed once a day in the middle of the corresponding photophase (12:00, 04:00 and 20:00 h, respectively). Then, in the weekends (2 days), fish were always returned to the Morning shift. As controls, 16 fish were maintained under a non-shifting LD cycle condition (CONTROL) throughout the whole experiment, with lights on from 08:00 to 16:00 h. Rest-activity rhythm (RAR) of fish subjected to SHIFT showed several symptoms of chronodisruption, such as a decrease in the percentage of diurnal activity and a reduction of the relative amplitude and the circadian function index with time. When a periodogram analysis was performed, RAR of N. furzeri under SHIFT conditions showed up to three separate circadian components: one longer than 24 h (26.5 h) that followed the weekly 8 h delays; a short-period component (~23 h) that was related to the weekend's phase advances, and finally, a 24 h component. The shifting LD schedule also affected fish CS at a molecular level, with several significant differences in the expression of core genes of the molecular clock (bmal1 , clock , rorα , rev - erbα) between SHIFT and CONTROL animals. RAR impairment along with changes in clock gene expression could be associated with high stress and accelerated aging in these fish. Highlights • This study proposes for the first time the use of a "5+2" shifting light-dark schedule on a diurnal vertebrate model; • Rest-activity rhythm of fish subjected to a shifting light-dark schedule showed several symptoms of chronodisruption; • The shifting light-dark schedule affected fish circadian system at a molecular level; • We found several differences in the expression of core genes of the molecular clock between control and shift animals. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to identify associations among the sleep disturbance, fatigue, job stress, and blood and body fluid (BBF) exposure of shift-work nurses. Methods: A total of 299 shift-work nurses from two tertiary hospitals were enrolled in this study. We used the Insomnia Severity Index (ISI), and the Fatigue Severity Scale (FSS), and the Korean Occupational Stress Scale-Short Form (KOSS-SF) to evaluate sleep disturbance, fatigue, and job stress, respectively. The data were analyzed using t-test or chi-squared test and Logistic regression analysis using the SPSS 23.0 program. Results: We found that 43.8% of participants reported BBF exposure over the past year. Splash or exposure to broken skin of BBF were most frequent (56.9%), and followed by needlestick injuries (30.4%) and sharp injuries (12.8%). Age, hospital, working period, level of stress, sleep disturbance (ISI≥15), fatigue (FSS score≥4), job demand and organizational climate subset in KOSS-SF were significantly associated with BBF exposure in shift-work nurses. In multivariate analysis after adjusting age and hospital, the risk factors of BBF exposure in shift-work nurses were the level of stress and fatigue (FSS score≥4). Conclusion: Fatigue and job stress were related to BBF exposure in shift-work nurses. Our results suggest that management of sleep disturbance, fatigue, and high job stress in shift-work nurses is needed to reduce risk of BBF exposure. [ABSTRACT FROM AUTHOR]

Abstract: Aims: Use of temporary nursing staff is contentious and expensive. Using e‐rostering data from 77 hospital units, this research investigates whether longer roster lead‐times reduce temporary staff usage. Background: It is commonly assumed that longer roster approval lead‐times, the time from when a roster is approved, to when it is worked, result in better, more cost‐effective rosters. Consequently, many hospitals target lead‐times of 6 weeks, a figure recommended for the UK National Health Service in a recent governmental review. This contrasts with the minimum lead‐time advocated by New South Wales Ministry of Health, which advises a shorter lead‐time of 2 weeks. Using data from 77 hospital units, this paper explores this assumed relationship. Design: Using data extracted from the e‐rostering system of an NHS Acute Foundation Trust, this study uses linear regression analysis to explore the relationship between roster approval lead‐time and temporary staff usage. The data were captured over a period of 9 months from 15 February 2016–23 October 2016, a total of 693 rosters. Results/Findings: This research suggests that late roster approval may contribute to as much as 37% of temporary staff usage, while approval 4–6 weeks prior to the roster being worked reduces this to approximately 15%. However, this is only relevant under specific conditions. Importantly, this should be considered before mandating lead‐times across all units. Conclusions: This research implies that the optimum approval lead‐time lies between 4–6 weeks; however, given other challenges, achieving this in practice may prove difficult. [ABSTRACT FROM AUTHOR]

The circadian disruption in shift-workers is suggested to be a risk factor to develop overweight and metabolic dysfunction. The conflicting time signals given by shifted activity, shifted food intake and exposure to light at night occurring in the shift-worker are proposed to be the cause for the loss of internal synchrony and the consequent adverse effects on body weight and metabolism. Because food elicited signals have proven to be potent entraining signals for peripheral oscillations, here we review the findings from experimental models of shift-work and verify whether they provide evidence about the causal association between shifted feeding schedules, circadian disruption and altered metabolism. We found mainly four experimental models that mimic the conditions of shift-work: protocols of forced sleep deprivation, of forced activity during the normal rest phase, exposure to light at night and shifted food timing. A big variability in the intensity and duration of the protocols was observed, which led to a diversity of effects. A common result was the disruption of temporal patterns of activity; however, not all studies explored the temporal patterns of food intake. According to studies that evaluate time of food intake as an experimental model of shift-work and studies that evaluate shifted food consumption, time of food intake may be a determining factor for the loss of balance at the circadian and metabolic level. [ABSTRACT FROM AUTHOR]

Introduction. Shift-work determinates irregular nutrition habits. The quality as well as the quantity of meals consumed by shift-workers can significantly affects their health. Objective. The aim of this study was to evaluate the dietary habits of people performing shift work in the Bogdanka mine. Material and Methods. The study was carried out in the Bogdanka mine in Leczna. The questionnaire, which was designed by the author of this dissertation, was conducted among 700 shift-workers, working underground. The results were subjected to statistical analysis based on STATISTICA v. 7.1 (StatSoft, Poland) software. Results. Nearly half of respondents reported regular consumption of meals (40.0%) Interviewees admitted having warm meals during the day (81.4%). The most frequently consumed meal during the day was the hot one (50.9%), three meals and more were consumed the least frequently (8.1%). Almost half of respondents considered their eating habits as inappropriate (46.3%). Among those, nearly half (68.2%) stated that shift – work is the reason for their nutrition habits. More than half of respondents (66.0%) admitted that shift work hampers regular consumption of meals. Conclusions. Shift work makes nourishment and regular consumption difficult. It contributes to the limited amount of warm meals eaten during the day. In order to maintain preventive health care and the improvement of quality of life, shift workers should be provided with an easier access to meals (including warm one) at specified times of the day.

This study examined the impact of eating during simulated night shift on performance and subjective complaints. Subjects were randomized to eating at night (n=5; 23.2 ± 5.5 y) or not eating at night (n=5; 26.2 ± 6.4 y). All participants were given one sleep opportunity of 8 h (22:00 h-06:00 h) before transitioning to the night shift protocol. During the four days of simulated night shift participants were awake from 16:00 h-10:00 h with a daytime sleep of 6 h (10:00 h-16:00 h). In the simulated night shift protocol, meals were provided at ≈0700 h, 1900 h and 0130 h (eating at night); or ≈0700 h, 0930 h, 1410 h and 1900 h (not eating at night). Subjects completed sleepiness, hunger and gastric complaint scales, a Digit Symbol Substitution Task and a 10-min Psychomotor Vigilance Task. Increased sleepiness and performance impairment was evident in both conditions at 0400 h (p<0.05). Performance impairment at 0400 h was exacerbated when eating at night. Not eating at night was associated with elevated hunger and a small but significant elevation in stomach upset across the night (p<0.026). Eating at night was associated with elevated bloating on night one, which decreased across the protocol. Restricting food intake may limit performance impairments at night. Dietary recommendations to improve night-shift performance must also consider worker comfort. [ABSTRACT FROM AUTHOR]

We examine the relationships between the working arrangements of mineworkers and behavioural issues in their children, using a large Australian matched-pair dataset of workers and their partners. The findings suggest both that workers’ work conditions, and aspects of safety and security influence aspects of child behaviour, reflecting not least the results of tiredness, emotional exhaustion and sleep interruption. In addition, it appears that child behaviour probably influences the pressure experienced by their parents and hence their attitudes towards aspects of work. [ABSTRACT FROM AUTHOR]

The author comments on a study published within the issue which investigated the prevalence of fatigue among anaesthetic junior doctors working in the National Health Service in Great Britain. Topics covered include the significance of having doctors take regular breaks to the delivery of safe, effective patient care, the cumulative effects of sleep deprivation especially among those who work night shifts, and the likely errors in care and judgment caused by fatigue.