Shift work disorder among oil rig workers in the North Sea

Effects of sleep and circadian rest-activity rhythms on daily pain severity in women with temporomandibular disorders

ABSTRACT

Although a robust connection between sleep and pain is established, the extent to which circadian rest-activity rhythms contribute toward unique variations in pain, beyond what is elucidated by sleep, remains uncertain. Furthermore, it is largely unknown whether sleep and circadian rest-activity rhythms have interactive effects on daily pain severity. Using wrist actigraphy and daily pain diaries, data from 140 women with temporomandibular disorders and insomnia symptoms were analyzed over a 14-day period. Sleep duration and continuity were quantified by using total sleep time (TST) and wake after sleep onset (WASO), and circadian rest-activity rhythms were characterized with the Relative Amplitude (indicating strength/robustness of rest-activity rhythm) and Intradaily Variability metrics (representing rhythm fragmentation). Linear mixed-effects modeling revealed that both TST (b = -0.11, P = 0.006) and WASO (b = 0.18, P = 0.006) from the previous night, along with Relative Amplitude (b = -2.56, P = 0.001) from the past 24 hours, predicted next-day pain severity. Among the 4 interaction effects tested, both Intradaily Variability (b = 1.52, P = 0.034) and Relative Amplitude (b = -1.52, P = 0.003) moderated the relationship between WASO and next-day pain severity; on days characterized by less robustness (lower Relative Amplitude) or greater fragmentation (higher Intradaily Variability) in the circadian rest-activity rhythm, the positive association between previous night WASO and next-day pain severity intensified. These findings highlight the complex interplay among sleep, circadian rest-activity rhythms, and pain. While preliminary, our findings indicate that interventions aimed at improving both sleep and restoring circadian rhythms may provide enhanced benefits for managing chronic pain.

Assessment of sleep quality, fatigue and its association with occupational injuries among shift workers in an electronic industrial environment

Objectives. This study explores the association between sleep quality, cumulative fatigue and occupational injuries among shift workers in Pakistan's manufacturing industries. Methods. The study surveyed 200 shift workers using a self-administered questionnaire. Sleep quality was assessed with the Pittsburgh sleep quality index (PSQI), and fatigue with the standard shiftwork index (SSI). Statistical analyses included t tests, χ2 tests and logistic regression. Results. Night shift employees had higher odds of occupational injuries (odds ratio [OR] 3.591, 95% confidence interval [CI] [1.079, 11.944], p = 0.037) compared to day shift workers. Cumulative fatigue (OR 3.044, 95% CI [1.145, 8.089], p = 0.026) and PSQI global score (OR 1.249, 95% CI [1.002, 1.556], p = 0.048) also indicated an increased injury risk. Conclusion. Night shift workers experienced poorer sleep quality, higher fatigue and increased injuries than day shift workers. Employers should implement artificial intelligence to detect and manage fatigue, set strategic shift schedules for maximum sleep opportunities and train workers to improve sleep quality.

The moderating role of protective factors in shift work disorder and health outcomes: A cross-sectional study

This study investigated whether sleep-specific (e.g. chronotype) and traditional (e.g. resilience) protective factors were associated with reduced shift work disorder (SWD) risk and explored their role as moderators in the relationship between SWD risk and health. Shift workers (n = 126) participated in a cross-sectional study evaluating SWD risk (i.e. low vs. high; SWD-screening Questionnaire), mental health (Patient Health Questionnaire-9; Generalized Anxiety Disorder Questionnaire-7), physical health (Subjective Health Complaints Inventory), sleep (Pittsburgh Sleep Quality Index; Insomnia Severity Index; Epworth Sleepiness Scale), and protective factors (Resilience Scale; Social Provisions Scale; Survey of Perceived Organizational Support; Short Impulsive Behavior Scale; Circadian Type Inventory; reduced-Morningness-Eveningness Questionnaire). Logistic regressions revealed lower sleep languidity was associated with reduced odds (OR = 0.88 [0.79,0.96]) for having high SWD risk. Multiple regression analyses showed in shift workers with high social support or morningness, having high SWD risk was not associated with increased depression symptoms, or insomnia severity and poor sleep quality, respectively. Finally, in those with high or medium levels of perceived organizational support, high SWD risk was not associated with increased gastrointestinal and allergy complaints. Longitudinal research with larger samples is needed to confirm the moderating role of protective factors in the relationship between SWD risk and health.

A latent profile analysis of shift work tolerance among Chinese male sailors during a prolonged non-24-h rotating shift schedule at sea

Shift work tolerance (SWT) refers to the ability to adapt to shift work without significant adverse consequences. The present study aimed to examine the individual differences in SWT and their predictors and outcomes. Latent profile analyses were conducted using cross-sectional data collected form 448 Chinese male sailors who experienced a prolonged (>30 d) non-24-h rotating shift schedule at sea. Depression, anxiety, sleep disturbance, fatigue, domestic disruption, job satisfaction, work engagement, digestive and cardiovascular symptoms were included as indicators of SWT. The results showed that there existed 2 latent profiles of SWT named as High SWT group and Low SWT group. High SWT group was characterized by low levels on all negative bio-psycho-social outcomes but high levels of work engagement and job satisfaction, while Low SWT group exhibited completely opposite characteristics compared to High SWT group. The level of hardiness could predict profile membership that those with higher level of hardiness were more likely to belong to High SWT group. However, there were no significant differences observed in job performance between two groups. In conclusion, hardiness can serve as a predictor of personnel selection for shift work and hardiness-based intervention programs should be encouraged among the shift workers.

Dysfunction of large-scale brain networks underlying cognitive impairments in shift work disorder

It has been demonstrated that shift work can affect cognitive functions. Several neuroimaging studies have revealed altered brain function and structure for patients with shift work disorder (SWD). However, knowledge on the dysfunction of large-scale brain networks underlying cognitive impairments in shift work disorder is limited. This study aims to identify altered functional networks associated with cognitive declines in shift work disorder, and to assess their potential diagnostic value. Thirty-four patients with shift work disorder and 36 healthy controls (HCs) were recruited to perform the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and resting-state functional scans. After surface-based preprocessing, we calculated within- and between-network functional connectivity (FC) using the Dosenbach atlas. Moreover, correlation analysis was done between altered functional connectivity of large-scale brain networks and scores of cognitive assessments in patients with shift work disorder. Finally, we established a classification model to provide features for patients with shift work disorder concerning the disrupted large-scale networks. Compared with healthy controls, increased functional connectivity within-networks across the seven brain networks, and between-networks involving ventral attention network (VAN)-subcortical network (SCN), SCN-frontoparietal network (FPN), and somatosensory network (SMN)-SCN were observed in shift work disorder. Decreased functional connectivity between brain networks was found in shift work disorder compared with healthy controls, including visual network (VN)-FPN, VN-default mode network (DMN), SMN-DMN, dorsal attention network (DAN)-DMN, VAN-DMN, and FPN-DMN. Furthermore, the altered functional connectivity of large-scale brain networks was significantly correlated with scores of immediate memory, visuospatial, and delayed memory in patients with shift work disorder, respectively. Abnormal functional connectivity of large-scale brain networks may play critical roles in cognitive dysfunction in shift work disorder. Our findings provide new evidence to interpret the underlying neural mechanisms of cognitive impairments in shift work disorder.

More than sleep problems? Testing five key health behaviors as reasons for quality of life issues among shift workers

BACKGROUND

The shift work schedule is a common work arrangement that can disrupt typical sleep-wake rhythms and lead to negative health consequences. The present study aims to examine the effect of shift work on health-related quality of life (QoL) and explore potential behaviorial mediators (i.e., sleep, eating, exercise, smoking, drinking).

METHODS

A cross-sectional survey was conducted among 4,449 petroleum workers in southwest China. Data on shift work status, health behaviors, and physical and mental health QoL were collected. We tested our model using path analysis and the Monte Carlo approach among 2,129 included participants.

RESULTS

After adjusting for covariates, shift work did not exhibit a significant direct association with QoL. However, shift work indirectly related to poorer physical health quality of life via less frequent healthy food consumption; shift work also indirectly related to poorer mental health QoL via both less frequent healthy food consumption and physical exercise. No significant indirect effects were found via sleeping, smoking, or drinking.

CONCLUSIONS

Results suggest that shift work presents a challenge for QoL among Chinese petroleum workers due to their lesser engagement in two specific health behaviors: healthy eating and physical exercise. Healthy eating and exercise may present an even more prominent threat to shift workers' QoL than sleep and substance use. Strategies targeting shift work schedule as well as eating and exercise behaviors may help protect against poor QoL and adverse physical and mental health outcomes in this vulnerable group.

The effect of cumulative night shift duties on insomnia, fatigue, and mental health in intensive care unit

Background

Night shift duties are crucial in the ICU to ensure care continuity, where critically ill patients require round-the-clock care. However, cumulative night shift duties may disturb circadian rhythm, insomnia, fatigue, and depression, and require further elucidation.

Objectives

This study aims to examine the negative consequences of various night shift patterns on insomnia, fatigue, and mental health of ICU Workers.

Methods

A cross-sectional study examined how cumulative night shift duty affects insomnia, fatigue, and mental health in critical care providers (CCPs).

Results

A total of 1006 participants completed this study between June 2022 and March 2023, including 54.5 % males. About 35 % were between 20 and 30 years of age, and Respiratory Therapists accounted for approximately 46.5 % of the entire sample. Most of our respondents (476; 47 %) reported working night shifts, with a monthly range of 8-15 nights. The prevalence rates for moderate to severe clinical insomnia, fatigue, and moderate to severe depression were 42 %, 48 %, and 32 %, respectively. CCPs working 8-15 nights had a 2-fold risk of clinical insomnia than those working fewer than eight nights with (AOR) and 95 % (CI) of 2.12 and 1.41-3.20, while those working ≥16 nights per month had a greater incidence of clinical insomnia compared to those working <8 nights per month, AOR (CI): 3.09 (1.90-5.03). Only those working ≥16-night shifts per month had a substantially higher fatigue risk compared to those working < 8-night shifts per month, with an AOR (CI) of 1.92 (1.19-3.08). Working 8-15-night shifts per month increases depression risks by 34 % compared to the <8-night shifts group, AOR (CI): 1.34 (0.87-2.08). Those working ≥16-night shifts per month showed a higher depression risk than those working <8-night shifts, AOR (CI): 2.53 (1.53-4.19).

Conclusion

A cumulative night shift above eight nights per month is linked with an increased risk of insomnia, fatigue, and depression. The risk of these conditions was significantly directly proportional to the number of night shifts performed per month.

Shift Work Sleep Disorder and Mental Health: An Integrative Review of Neurobiological, Sociological, and Psychological Perspectives With Public Policy Implications

Shift workers support critical 24-hr operations; their health can be impaired by disrupted circadian rhythms and dysfunctional sleep. Shift work sleep disorder (SWSD) is a prevalent condition with significant psychological consequences. Nurse leaders have not yet implemented effective policies to prevent SWSD and optimize shift workers' mental health. The purpose of this integrative review was to examine research about SWSD within the context of neurobiological, sociological, and psychological perspectives that can inform policy changes. The Centers for Disease Control and Prevention Policy Analytic Framework was used to determine the priority recommendations. A search of three databases provided 19 research articles about SWSD and mental health, which illustrated how SWSD is common around the world in many occupations. Backward-rotating schedules and quick returns were risk factors for SWSD. In addition, SWSD was associated with circadian languidity, sleep reactivity, depressive symptoms, and anxiety. Collectively, the studies lacked objective measures of sleep and circadian rhythms, which has hindered the ability to devise interventions that will target the neurobiological causes of SWSD. The research also lacked attention to important sociological factors, such as workers' pay and benefits. Using these findings, nurse leaders can contribute to public policy reforms that increase funding for more rigorous SWSD research. Lawmakers should be advised by nurse leaders to enforce new regulations that provide incentives for employers to create healthier workplaces, such as prohibiting the overuse of schedules that make employees vulnerable to SWSD and providing funds for interventions to prevent SWSD and support mental health.

Differences in shift and work-related patterns between metropolitan and regional/rural healthcare shift workers and the occupational health and safety risks

OBJECTIVES

To explore if there are differences in shift patterns and work-related factors between metropolitan and regional/rural healthcare shift workers and their risk of poor sleep and mental health. Furthermore, explore whether these factors impact on medical errors, workplace and car/near car accidents.

DESIGN

A cross-sectional study.

SETTING

An anonymous online survey of healthcare shift workers in Australia.

PARTICIPANTS

A total of 403 nurses, midwives and paramedics completed the survey.

MAIN OUTCOME MEASURES

Sample characteristics, employment location, shift work-related features, sleep and mental health measurements, workplace accidents, medical errors and car/near car accident post shift.

RESULTS

Regional/rural healthcare shift workers were significantly older, had more years' experience, worked more nights, on-call and hours per week. Those in metropolitan areas took significantly longer (minutes) to travel to work, had higher levels of anxiety, increased risk of shift work disorder, reported significantly more workplace accidents and were more likely to have a car/near car accident when commuting home post shift. Both groups reported ~25% having a medical error in the past year. Workplace accidents were related to more on-call shifts and poor sleep quality. Medical errors were associated with fewer years' experience, more evening shifts and increased stress. Car accidents were associated with metropolitan location and increased depression.

CONCLUSION

Differences in work-related factors between metropolitan and regional/rural healthcare shift workers were observed. Some of these factors contributed to occupational health and safety risks. Further exploration is needed to understand how to reduce occupational health and safety risks, and improve employee and patient safety both in both regional/rural and metropolitan areas.

Shiftwork sleep disorder and associated factors among nurses working at public hospitals in Harari Regional state and Dire Dawa Administration, Eastern Ethiopia: a cross-sectional study

BACKGROUND

Shiftwork sleep disorder is one of the most common health-related effects of Shiftwork, particularly among healthcare workers. It is a chronic condition that is directly related to a person's work schedule. In Ethiopia, although a mental health strategy is in place, little attention is given to studies that focus on shiftwork sleep disorders among nurses. This study aimed to determine the magnitude of shiftwork sleep disorder and associated factors among nurses working at public hospitals in Harari Regional State and the Dire Dawa Administration.

METHODS

Institutional based cross-sectional study was conducted from June 1-30, 2021 among 392 nurses selected by a simple random sampling technique. A structured interviewer-guided self-administered questionnaire was used for data collection. The International Classification of Sleep Disorders 3rd edition (ICSD-3), Bargen Insomnia Scale (BIS) and Epworth Sleepiness Scale were used to assess shift-work sleep disorder. The data were entered into EpiData and exported to SPSS for analysis. Bivariable logistic regression was used to see the association between the outcome and the explanatory variables. Bivariate and Multivariate analyses were performed, and AOR with 95% CI was used to measure the strength of the association. Those variables with a p-values of < 0.05 were considered as statistically significant.

RESULTS

In this study, the magnitude of shiftwork sleep disorder among nurses was 30.4% (95% CI: 25.4-34.5). Being female (AOR = 2.4, 95% CI: 1.3, 4.2), working an average number of nights > 11 per month in the last 12 months (AOR = 2.5, 95% CI: 1.3, 3.8), and khat use in the last 12 months (AOR = 4.9, 95% CI: 2.9, 8.7) were significantly associated with the shiftwork sleep disorder.

CONCLUSIONS

The study revealed that about one-third of the nurses had a shiftwork sleep disorder implying a high burden of the problem among nurses in the study setting, which endangers nurses, patients, and the healthcare system. Being female, working an average number of nights > 11 per month in the last 12 months, and khat use showed statistically significantly associated with the shiftwork sleep disorder. Early detection of shiftwork sleep disorder, having a policy on khat use and considering rest/recovery while scheduling work time should be addressed to prevent shiftwork sleep disorder.

A scoping review of the evidence for the impact of pharmacological and non-pharmacological interventions on shift work related sleep disturbance in an occupational setting

Background: Shift work is essential in society but can be detrimental to health and quality of life and is associated with decreased productivity and increased risk of accidents. Interventions to reduce these consequences are needed, but the extent and range of trial evidence for interventions for those most affected by their shift-work schedules is unclear. We therefore carried out a scoping review to assess the availability of evidence to inform the development and evaluation of future interventions. Methods: We aimed to identify clinical trials of any intervention for shift work-related sleep disturbance that included a comparator group, where the intervention was delivered in an occupational setting. We searched Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, CINAHL, EMBASE, Medline and Science Citation Index from inception to 30 th March 2020 for relevant citations. Citations were screened by two independent reviewers, a third reviewer resolved disagreements. Data were extracted by two independent reviewers. Results: From 1250 unique citations, 14 studies met inclusion criteria for comparative trials of treatment in an occupational setting. There were five trials of hypnotics, five trials of stimulants, and four trials of non-pharmacological therapies (cognitive behavioural therapy, light therapy, aromatherapy and herbal medicine). Outcomes included sleep parameters, day-time sleepiness, and quality of life. There were no consistently reported outcomes across trials. Conclusions: Interventions fell into three distinct groups investigated in distinct time periods without progression from efficacy trials to wider-scale interventions. The lack of consistent patient-reported outcome measures limits synthesising findings. Some trials focussed on optimising sleep, others on reducing wake-time sleepiness. Adequately powered trials of existing interventions are needed, with the development and testing of novel combination treatments in patients with well-defined shift work sleep disorder. A core set of clinically relevant outcomes will develop and standardise the evidence-base for shift work sleep disorder.

Do holidays change subjective sleep length or sleep debt in shift work disorder?

In shift work disorder (SWD), disturbed sleep acutely impairs employees' recovery, but little attention has been paid to sleep during longer recovery periods. We examined how holidays affect self-estimated sleep length, sleep debt, and recovery in cases of SWD. Twenty-one shift workers with questionnaire-based SWD and nine reference cases without SWD symptoms completed a questionnaire on recovery and sleep need. They also reported sleep length on two separate occasions: during a work period and after ≥ 2 weeks of holidays. Sleep debt was calculated by subtracting sleep length from sleep need. We used parametric tests to compare the groups and the periods. The groups reported shorter sleep on workdays than during holidays (median difference: SWD group 1.7 h, p<0.001; reference group 1.5 h; p<0.05). The SWD group's self-estimated sleep during holidays increased less above the sleep need (median 0.0 h) than the reference group's sleep (1.0 h, p<0.05). In addition, the SWD group reported good recovery from irregular working hours less often (14%) than the reference group (100%, p<0.001). Although holidays were generally associated with longer sleep estimates than workdays, employees with SWD experienced consistently less efficient recovery than those without SWD.

US research needs related to fatigue, sleep, and working hours among oil and gas extraction workers

BACKGROUND

During 2003-2013, 1189 US oil and gas extraction (OGE) workers died while working, resulting in an average annual workplace fatality rate seven times that for all US workers. OGE work commonly involves long hours, shiftwork, irregular schedules, and long commutes, but effects of these factors on fatigue, occupational injury, and illness in OGE are largely unknown.

METHODS

A scoping review of relevant OGE research during 2000-2019 was completed and supplemented by input from a NIOSH-sponsored Forum.

RESULTS

Seventy-eight papers were identified; 76% reported only offshore research. Five themes for research needs emerged: build knowledge about the impacts of fatigue; explore interactions between on- and off-the-job risk factors; identify and evaluate interventions; assess effectiveness of technology; and increase the diffusion of fatigue risk management information.

CONCLUSIONS

Further collaboration between researchers and OGE operators and contractors can lead to action-oriented recommendations to mitigate the effects of fatigue, inadequate sleep, and shiftwork.

National strategy on the integration of sleep and circadian rhythms into public health research and policies: Report from the Canadian Sleep and Circadian Network

Scientists in sleep and circadian rhythms, public health experts, healthcare providers, partners, and stakeholders convened in 2020 for a 2-day meeting organized by the Canadian Sleep and Circadian Network to develop a national strategy for the integration of sleep and circadian rhythms into public health and policies in Canada. The objective of this paper is to present the national strategy that emerged from this meeting of 60 participants from across Canada. The meeting focused on 4 key target priorities: (1) atypical working schedules, (2) sleep and circadian rhythms of children and adolescents, (3) insomnia, and (4) impact of sleep apnea on health. Following constructive discussions over 2 days, it was decided that the following 4 strategic objectives should be prioritized to accelerate the integration of sleep and circadian rhythms into public health policies in Canada: (1) Increase public health sleep and circadian rhythm research, (2) Increase public health education and knowledge mobilization on sleep, (3) Inform and support public health sleep interventions and policies, and (4) Promote sleep health training. The participants recommended that research and public health efforts should address the needs along the continuum of sleep health. The committee noted that strategies and interventions could differ across contexts, settings, sectors, and jurisdictions. The national strategy also identified high-priority research questions in public health and recommended mechanisms to build research capacity, providing a path forward for the integration of sleep and circadian rhythms into public health research and policies.

The association between shift work disorder and turnover intention among nurses

Background

Shift work disorder (SWD) is highly prevalent among shift-working nurses and has multiple negative health-related effects. There is a dearth of insight into career-related decisions made by nurses suffering from SWD, for instance in terms of their intention to quit work (turnover intention). In this study, we aimed to investigate the association between SWD and turnover intention among nurses, and the individual and work-related correlates of turnover intention.

Method

Data were derived from the ongoing longitudinal cohort study “SUrvey of Shift work, Sleep and Health (SUSSH)” among Norwegian nurses. An annual survey was initiated in 2008/2009 (N = 2965). The present study used data collected in year 2015 (wave 7) and 2016 (wave 8). Nurses were included if: 1) they were working as nurses in both 2015 and 2016, and 2) had completed a three-item scale adapted from the Michigan Organizational Assessment Questionnaire assessing turnover intention (in wave 8), and 3) did not only work day-shifts. SWD was measured in wave 7 with three questions based on the minimal criteria from the third edition of the International Classification of Sleep Disorders. Job demands, decision latitude, and social support at the workplace were measured with subscales of the Swedish Demand-Control-Support Questionnaire.

Results

Eight Hundred eighty-nine nurses were included. The results from the hierarchical linear regression showed that SWD predicted turnover intention one year later, i.e. from 2015 to 2016 (F_1,835 = 6.00, p < 0.05; β = 0.084, p = 0.015). The findings remained significant when controlling for age, sex, organizational tenure, number of nights worked, shift work schedule and workplace social support, job demands and decision latitude.

Conclusion

This study showed that SWD is associated with turnover intention, even when controlling for individual and work-related variables.

Health-promoting work schedules: protocol for a large-scale cluster randomised controlled trial on the effects of a work schedule without quick returns on sickness absence among healthcare workers

INTRODUCTION

In shift work, quick returns refer to transitions between two shifts with less than 11 hours available rest time. Twenty-three per cent of employees in European countries reported having quick returns. Quick returns are related to short sleep duration, fatigue, sleepiness, work-related accidents and sickness absence. The present study is the first randomised controlled trial (RCT) to investigate the effect of a work schedule without quick returns for 6 months, compared with a work schedule that maintains quick returns during the same time frame.

METHODS AND ANALYSIS

A parallel-group cluster RCT in a target sample of more than 4000 healthcare workers at Haukeland University Hospital in Norway will be conducted. More than 70 hospital units will be assessed for eligibility and randomised to a work schedule without quick returns for 6 months or continue with a schedule that maintains quick returns. The primary outcome is objective records of sickness absence; secondary outcomes are questionnaire data (n≈4000 invited) on sleep and functioning, physical and psychological health, work-related accidents and turnover intention. For a subsample, sleep diaries and objective sleep registrations with radar technology (n≈ 50) will be collected.

ETHICS AND DISSEMINATION

The study protocol was approved by the Regional Committee for Medical and Health Research Ethics in Western Norway (2020/200386). Findings from the trial will be disseminated in peer-reviewed journals and presented at national and international conferences. Exploratory analyses of potential mediators and moderators will be reported. User-friendly outputs will be disseminated to relevant stakeholders, unions and other relevant societal groups.

TRIAL REGISTRATION NUMBER

NCT04693182.

Impact of sleep timing on attention, sleepiness, and sleep quality among real-life night shift workers with shift work disorder: a cross-over clinical trial

STUDY OBJECTIVES

To examine the effect of sleep timing intervention on sleep quality, attention, and sleepiness at work among night shift workers with shift work disorder.

METHODS

We recruited 60 real-life night shift workers through advertisements to participate this cross-over clinical trial. Shift work disorder was confirmed with interview and sleep log. Participants were designated to follow evening sleep (15:00-23:00) and morning sleep (09:00-17:00) schedules in a randomized order. Chronotype was confirmed by the Munich Chronotype Questionnaire. Sleep behaviors and light exposure were recorded using actigraphy. Outcome measures were sleepiness evaluated by the Karolinska Sleepiness Scale, sleep quality evaluated by the Pittsburgh Sleep Quality Index, and attention performance assessed with psychomotor vigilance test. Differences in outcome between the morning and evening sleep schedules were compared using repeated measures ANOVA.

RESULTS

The participants slept for longer durations during evening sleep schedules compared with morning sleep schedules. Lower sleepiness scores, higher sleep quality, and shorter reaction times and less lapse numbers in the psychomotor vigilance test were observed for participants during evening sleep schedules than morning sleep schedules after adjustment for light exposure and sleep duration. Significant interaction effects were observed for reaction time and lapse number between chronotype and sleep schedule, where the differences between sleep schedules were most prominent among those with late chronotypes.

CONCLUSIONS

It is recommended that night shift workers with shift work disorder arrange to sleep in the evening instead of the morning for better sleep and attention performance, especially those with late chronotypes.

TRIAL REGISTRATION

Sleep Schedule Intervention Study Among Night Shift Workers, https://clinicaltrials.gov/ct2/show/NCT04160572, ClinicalTrials.gov Identifier: NTC04160572.

The effectiveness of an individualized sleep and shift work education and coaching program to manage shift work disorder in nurses: a randomized controlled trial

STUDY OBJECTIVES

While insomnia and sleepiness symptoms are common in shift workers, 20%-30% experience more severe symptoms and meet the criteria for shift work disorder (SWD). SWD can lead to impairments in cognitive function, physical and mental health, and reduced productivity and increased risk of workplace injury. The aim of this study was to deliver and evaluate a shift work individual management coaching program, focusing on sleep education, promoting good sleep hygiene, and providing individualized behavioral strategies to cope with shift schedules.

METHODS

A clustered randomized controlled trial of sleep education and sleep disorders screening was undertaken, based on hospital wards at a tertiary hospital in Melbourne, Australia. Participants identified as high risk for SWD underwent one of two 8-week programs, a shift work individualized management program, or an active control. The primary outcome was ward-based sick leave. Secondary outcomes were SWD risk, sleep hygiene, insomnia, depression, and anxiety. A total of 149 nurses, across 16 wards (96% female, 34.66 ± 11.99 years) completed both baseline and follow-up questionnaires (23.9% were high risk SWD).

RESULTS

There was no significant reduction in sick leave between intervention and control wards (mean difference = 1.2 days, P = .063). Improvements were seen in insomnia (P < .0001) and depression (intervention, P ≤ .0001, control, P = .023) in both groups, but were not significantly different between programs. Anxiety (P = .001. control P = .079) and Functional Outcomes of Sleep Questionnaire 10 (P = .001 control P = .056) improved only for the intervention.

CONCLUSIONS

This SWD intervention trial did not reduce sick leave compared to the active control but there was an improvement. Improvements in sleep hygiene, insomnia, depression, and anxiety severity were seen for both groups. Future intervention trials should consider including both sleep and mental health interventions, strategies to avoid between group contamination and the duration of programs for optimal behavioral modification.

CLINICAL TRIAL REGISTRATION

Registry: Australian New Zealand Clinical Trials Registry; Name: Sleep Health Management for Healthcare Workers; URL: https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12616000369426; Identifier: ACTRN12616000369426.

CITATION

Booker LA, Sletten TL, Barnes M, et al. The effectiveness of an individualized sleep and shift work education and coaching program to manage shift work disorder in nurses: a randomized controlled trial. J Clin Sleep Med. 2022;18(4):1035-1045.

The Adverse Environmental Impact Factors Analysis on Fly-In-Fly-Out Personnel at Industrial Enterprises

(1) Background: the research purpose is to identify and describe the general and different factors of adverse environmental impact on FIFO personnel at industrial enterprises at different levels of differential analysis of professional activity. (2) Methods: The research involved 359 employees of industrial enterprises with FIFO work organization. The study was carried out using a questionnaire, including a subjective assessment of the discomfort of three groups of negative environment impact factors to the FIFO personnel: climatic-geographical, industrial and social. (3) Results: The relationship between the increase in the degree of discomfort of production factors due to the in-fluence of climatic, geographical and social conditions has been established. With a various location of objects, the greatest discomfort is felt from the action of climatic and production factors; with varying degrees of group isolation and the shift period duration—all three groups, with the greatest influence of domestic and social; in various industries and enterprises—all three groups. (4) Conclusions: The differential analysis of the professional activities of FIFO personnel of industrial enterprises should be carried out at the following levels: the location of an industrial facility, the degree of group isolation, the duration of the shift period, the industry, the type of enterprise and the professional group.

Predictors of Shift Work Sleep Disorder Among Nurses During the COVID-19 Pandemic: A Multicenter Cross-Sectional Study

Background: Nurses have a high incidence of shift work sleep disorder, which places their health and patient safety in danger. Thus, exploring the factors associated with shift work sleep disorder in nurses is of great significance in improving their sleep health, nursing personnel staffing, and scheduling during the COVID-19 pandemic.

Objectives: The purpose of this study was to investigate the incidence of shift work sleep disorder during the COVID-19 pandemic and explore the factors associated with shift work sleep disorder in Chinese nurses.

Methods: This was a multicenter cross-sectional study using an online survey. Stratified cluster sampling was used to include 4,275 nurses from 14 hospitals in Shandong, China from December 2020 to June 2021. Stepwise multivariate logistic regression analysis and random forest were used to identify the factors associated with shift work sleep disorder.

Results: The prevalence of shift work sleep disorder in the sampled shift nurses was 48.5% during the COVID-19 pandemic. Physical fatigue, psychological stress, shift work more than 6 months per year, busyness during night shift, working more than 40 h per week, working more than four night shifts per month, sleeping more than 8 h before night shift, using sleep medication, irregular meals, and high-intensity physical activity were associated with increased odds of shift work sleep disorder. Good social support, good work-family balance, napping two or three times per week, resting more than one day after shifts, intervals of 8 days or more between shifts, and taking turns to rest during the night shift were associated with decreased odds of shift work sleep disorder.

Conclusions: Shift work sleep disorder may be associated with scheduling strategies and personal behavior during the COVID-19 pandemic. To reduce the incidence of shift work sleep disorders in nurses, nursing managers should increase night shift staffing, extend rest days after shift, increase night shift spacing, and reduce overtime, and nurses need to seek more family and social support and control their sleep schedules and diet.

Sleep medication and melatonin use among Norwegian nurses - A cross-sectional study

Aim

To estimate the prevalence of sleep medication and melatonin use among nurses and to assess if factors related to work, sleep or mental health, were associated with such use.

Design

A cross‐sectional study.

Methods

A questionnaire survey including 2,798 Norwegian nurses. Associations were estimated using a modified Poisson regression model.

Results

In total, 7.5%, 4.6% and 2.0% of the nurses included in the present study reported prescribed sleep medication, over‐the‐counter sleep medication or melatonin use in the last year, respectively. Short sleep duration, sleep problems and psychological conditions were strongly associated with both prescribed and over‐the‐counter sleep medication use. Nurses who worked more than 60 night shifts in the last year were at increased risk of sleep medication use.

Health and well-being of rotation workers in the mining, offshore oil and gas, and construction industry: a systematic review

Introduction

Rotation work, characterised by travelling long distances to work in isolated areas where workers typically rotate consecutive days working and living on-site with periods at home, is increasingly used in the resources and construction sectors globally. Such employment practices may have an impact on workers’ health and well-being. This systematic review explores the impact rotation work has on mental and physical outcomes in rotation workers in the resources and construction sectors.

Method

The PubMed, Medline, EMBASE, CINAHL, PsycINFO, and Scopus databases were systematically searched on 1 May 2020 to identify quantitative, qualitative and mixed-method studies addressing the health of rotation workers published in peer-reviewed journals. Findings from the studies were summarised narratively.

Results

Of 6268 studies retrieved, 90 studies were included in the review. Studies suggested higher prevalence of psychological distress in onshore rotation workers and higher overweight/obesity rates among rotation workers as compared with the general population. We found more sleep problems and higher levels of smoking during work periods compared with off-site days; and higher alcohol intake during off-site days compared with on-site days. Workers generally perceived their physical health status as good. High-perceived job demands (such as workload, repetitive work) were associated with mental distress and exhaustion, sleep problems and perceived poor physical health status, while high-perceived job resources (such as job clarity/control, support) were associated with low mental distress and exhaustion, less smoking and alcohol intake, and better sleep.

Conclusion

Rotation work is associated with several poorer health behaviours and outcomes, such as sleep problems, smoking, alcohol consumption and overweight/obesity. Interventions needed to improve rotation workers’ health should include maximising available job resources and reducing job demands. Further longitudinal studies are needed to explore the long-term health effects of rotation work and the short-term contextual effects of the different aspects of rotation work.

A scoping review of the evidence for the impact of pharmacological and non-pharmacological interventions on shift work related sleep disturbance in an occupational setting

Background: Shift work is essential in society but can be detrimental to health and quality of life and is associated with decreased productivity and increased risk of accidents. Interventions to reduce these consequences are needed, but the extent and range of trial evidence for interventions for those most affected by their shift-work schedules is unclear. We therefore carried out a scoping review to assess the availability of evidence to inform the development and evaluation of future interventions. Methods: We aimed to identify clinical trials of any intervention for shift work-related sleep disturbance that included a comparator group, where the intervention was delivered in an occupational setting. We searched Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, CINAHL, EMBASE, Medline and Science Citation Index from inception to 30th March 2020 for relevant citations. Citations were screened by two independent reviewers, a third reviewer resolved disagreements. Data were extracted by two independent reviewers. Results: From 1250 unique citations, 14 studies met inclusion criteria for comparative trials of treatment in an occupational setting. There were five trials of hypnotics, five trials of stimulants, and four trials of non-pharmacological therapies (cognitive behavioural therapy, light therapy, aromatherapy and herbal medicine). Outcomes included sleep parameters, day-time sleepiness, and quality of life. There were no consistently reported outcomes across trials. Conclusions: Interventions fell into three distinct groups investigated in distinct time periods without progression from efficacy trials to wider-scale interventions. The lack of consistent patient-reported outcome measures limits synthesising findings. Some trials focussed on optimising sleep, others on reducing wake-time sleepiness. Adequately powered trials of existing interventions are needed, with the development and testing of novel combination treatments in patients with well-defined shift work sleep disorder. A core set of clinically relevant outcomes will develop and standardise the evidence-base for shift work sleep disorder.

Prevalence of Insomnia in Various Industries and Associated Demographic Factors in Night-Shift Workers Using Workers' Specific Health Examination Data

This study aimed to investigate the prevalence of insomnia in various industries and the associated demographic factors. We searched the nationwide night-shift Workers’ Specific Health Examination (nsWSHE) data extracted in 2015 information on factors associated with insomnia, including sex, age, and the number of workers in the workplace. The prevalence of moderate insomnia in the total industry was 4.6%. Industries with a high prevalence of insomnia included the arts, sports, and recreation-related services industry, followed by the activities of household as employers industry, financial and insurance activities industry, human health and social welfare industry, and accommodation and food services activities industry. The prevalence of insomnia was higher in women. Age was a significant factor. In general, insomnia was highest among those aged ≥60 years. Insomnia was highest in small-sized companies with fewer than five employees compared to large enterprises with more than 1000 employees. This study is the first to analyze the prevalence of insomnia among night-shift workers who participated in the WSHEs. The findings of this study can be used to prioritize intervention policies for insomnia among night-shift workers.

Daylight Saving Time preferences in Norway: Do individual chronotype and home address' latitude and longitude matter?

Daylight Saving Time is highly debated and associated with several health risks. Health experts recommend terminating adjusting the clock time, and to keep permanent standard (winter) time year around. The aims of the study were to investigate preferences for keeping or terminating this biannual adjustment of clock times and for permanent standard or summer time, in the general Norwegian population. Furthermore, we aimed to investigate whether such preferences depended on individual chronotype and home address' latitude/longitude. The online survey included 47,194 participants. Chronotype was measured with the Composite Scale of Morningness (morning types, intermediate types, evening types). Results showed that 78.2% preferred to terminate adjusting the clock time. Summer time year around was preferred by 61.5% whereas 29.1% preferred standard time year around, and 9.4% did not have any preference. Preferences for terminating adjustment of clock times and summer time year around were found in all chronotypes and regardless of living south (latitude 58-59°N), north (latitude 69-71°N), west (longitude 5-6°E) or east (longitude 19-31°E). However, a relatively larger proportion of evening chronotypes preferred to terminate adjusting the clock time compared to morning chronotypes, and relatively more people living north or east preferred termination than people living south or west, respectively. Permanent standard time was more strongly preferred by extreme morning types in comparison with the other chronotypes. In conclusion, nearly four out of five participants reported to prefer to terminate adjusting the clock time, in line with recommendations. However, in contrast to advice from health experts, permanent summer time was preferred by twice as many as permanent standard time. Both chronotype and home address' latitude and longitude mattered in regard to such preferences, but only to a small degree.

The role of sleep hygiene in the risk of Shift Work Disorder in nurses

A high proportion (20%-30%) of shift workers experience Shift Work Disorder (SWD), characterized by chronic sleepiness and/or insomnia associated with work schedules. The reasons for individual variation in shift work tolerance are not well understood, however. The aim of this study was to identify individual factors that contribute to the risk of SWD. Nurses (n = 202) were categorized as low or high risk of SWD based on the Shift Work Disorder Questionnaire. Participants provided demographic and lifestyle information and completed the Sleep Hygiene Index (SHI) and Morningness-Eveningness Questionnaire (MEQ). High risk of SWD was associated with poorer sleep hygiene (SHI, 35.41 ± 6.19 vs. 31.49 ± 7.08, p < .0001) and greater eveningness (MEQ, 34.73 ± 6.13 vs. 37.49 ± 6.45, p = .005) compared to low risk. No other factors, including body mass index, marital status, having children, or caffeine or alcohol intake were significant. Logistic regression showed that SHI was the most significant contributing factor to SWD risk (odds ratio [OR] = 1.09, 95% confidence interval [CI] = 1.04 to 1.14). Standardized odds ratio further revealed that with every unit increase on the SHI score, the odds of being at high risk of SWD increased by 80% (OR = 1.84). Most individuals at high risk of SWD reported "always" or "frequently" going to bed at different times (79%) and waking at different times (83%; compared to 58%, p = .017, and 61%, p = .002, respectively for the low-risk group), as well as going to bed stressed/angry (67% vs. 41%, p < .0001) and/or planning/worrying in bed (54% vs. 22%, p < .0001). Interventions aimed at improving sleep hygiene practices and psychological health of shift workers may help reduce the risk of SWD.

Prevalence of Shift Work Disorder: A Systematic Review and Meta-Analysis

Objectives: No systematic review or meta-analysis concerning the prevalence of shift work disorder (SWD) has been conducted so far. The aim was thus to review prevalence studies of SWD, to calculate an overall prevalence by a random effects meta-analysis approach and investigate correlates of SWD prevalence using a random-effects meta-regression.

Methods: Systematic searches were conducted in ISI Web of Science, PsycNET, PubMed, and Google Scholar using the search terms “shift work disorder” and “shift work sleep disorder.” No restrictions in terms of time frame were used. Included studies had to present original data on the prevalence of SWD in an occupational sample published in English. A total of 349 unique hits were made. In all, 29 studies were finally included from which two authors independently extracted data using predefined data fields. The meta-regression included four predictors (diagnostic criteria, study country, type of workers, and sample size).

Results: The overall prevalence of SWD was 26.5% (95% confidence interval = 21.0–32.8). Cochran Q was 1,845.4 (df = 28, p < 0.001), and the I² was 98.5%, indicating very high heterogeneity across the observed prevalence estimates. Diagnostic criteria (International Classification of Sleep Disorders-2 = 0, International Classification of Sleep Disorders-3 = 1) and sample size were inversely related to SWD prevalence.

Conclusions: The prevalence of SWD was high across the included studies. The between-study disparity was large and was partly explained by diagnostic criteria and sample size. In order to facilitate comparative research on SWD, there is a need for validation and standardization of assessment methodology as well as agreement in terms of sample restrictions.

Changes in work schedule affect the prevalence of shift work disorder among Norwegian nurses - a two year follow-up study

This study aimed to explore how changes in the work schedule would affect the prevalence of Shift Work Disorder (SWD) over time. Two-year follow-up data from 1076 nurses participating in the longitudinal SUrvey of Shift work, Sleep and Health among Norwegian nurses (SUSSH) were included in the study. The questionnaires included measures of work-related factors, i.e., work schedule and numbers of night shifts and quick returns (QRs) worked the last year, as well as questions related to SWD according to the ICSD-3 diagnostic criteria at both baseline and at 2-year follow-up. Data were analyzed with paired samples t-tests, chi-square tests, and logistic regression analyses adjusting for sex and age. Terminating night work was the strongest predictor for recovering from SWD from baseline to follow-up (OR 10.91, 95% CI 6.11-19.46). Additionally, changing the work schedule from day work to night work from baseline to follow-up was the strongest predictor for developing SWD in the same period (OR 4.75, 95% CI 2.39-9.47). Reductions in number of nights (more than 10) and QRs (more than 10) worked the last year were associated with recovering from SWD between baseline and follow-up. Nurses who recovered from SWD had significantly reduced the mean number of night shifts worked the last year from 32.3 at baseline to 20.4 at follow-up (p = .001). Furthermore, an increase of more than 10 nights or more than 10 QRs worked the last year between baseline and follow-up predicted developing SWD. Nurses developing SWD between baseline and follow-up had significantly increased the mean number of nights worked the last year from 25.8 at baseline to 31.0 at follow-up (p =-.043). Changes in night work exposure were the strongest predictors for both recovering from or developing SWD from baseline to follow-up. Reducing exposure to night work and QRs were associated with recovering from SWD and increasing exposure to night work and QRs were associated with developing SWD. The results imply that unfavorable work schedules play a role in the development of sleep problems among nurses. These results may be useful when designing healthy working schedules.

Shift Work Disorder, Insomnia, and Depression among Offshore Oil Rig Workers

Objective: Numerous offshore jobs require 24-hour tasks, such as in industrial workplaces (eg, oil rigs). The purpose of this study was to assess shift work disorder (SWD), insomnia, daytime sleepiness, and depression among Iranian offshore oil rig workers in different shift schedules. Method : This cross-sectional study was conducted on Iranian offshore oil workers at the Persian Gulf. A questionnaire package consisted of Epworth Sleepiness Scale (ESS), Insomnia Severity Index (ISI), Beck Depression Inventory (BDI- II), and SWD filled. The scores were calculated among different groups of shift schedules (fixed-day, fixed-night, swing and standby shift workers). ISI, BDI-II, and ESS scores were also compared between individuals with or without SWD. Results: A total of 188 participants were recruited in the study, and all were male. The mean age was 37.06 ± 9.2 years. Among different shift schedules, the highest and lowest ISI and ESS scores were related to fixed-night shifts workers and fixed-day shift workers, respectively. ISI, ESS, and BDI mean scores in different shift schedules were not significantly different (p values = 0.14, 0.57, and 0.93, respectively). SWD was diagnosed in 57 (30.3%) of studied shift workers. The difference between SWD prevalence was not significant between different shift schedules (P value =0.13). Workers with SWD had higher ISI, ESS, and BDI-II score (P values <0.0001, <0.0001, and <0.0001, respectively) and workers without SWD had higher job satisfaction (p value = 0.04). Conclusion: SWD is considered as a serious health-related issue in Persian Gulf oil rig shift workers. Insomnia, daytime sleepiness, and depression are associated with SWD.

Shift work disorder and related influential factors among shift workers in China

BACKGROUND

Shift work may cause insomnia and sleepiness in individuals. The present study aimed to exam shift work disorder (SWD), and to investigate their associations with individual characteristics.

METHODS

A total of 1833 shift workers were assessed using the Pittsburg Sleep Quality Index, Epworth Sleepiness Scale (ESS), Composite Scale of Morningness (CSM), Circadian Type Inventory (CTI), Center for Epidemiologic Studies-Depression Scale (CES-D), Beck Anxiety Inventory (BAI) and other self-compiled socio-demographic questionnaires.

RESULTS

In the current sample, 17.1% shift workers have experienced insomnia symptoms, 20.9% were tested for daytime sleepiness, and 19.9% were categorized as having SWD. Logistics regressions revealed that history of mental disorders (OR = 2.04, 95% CI = 1.30-3.21), chronic physical illness (OR = 1.53, 95% CI = 1.17-1.99), CES-D scores (OR = 1.03, 95% CI = 1.02-1.05), BAI scores (OR = 1.04, 95% CI = 1.03-1.06), languid/vigorous tendencies (OR = 1.06, 95% CI = 1.03-1.10) were positively associated with the onset of SWD, while morningness (OR = 0.97, 95% CI = 0.94-0.99) decreased the odds of SWD onset.

CONCLUSIONS

These findings suggested that attention should be drawn to individuals with mental and chronic diseases in when scheduling work shifts. While SWD and its associates should be considered when providing psychological services to shift workers.

Differential DNA methylation in recovery from shift work disorder

The human DNA methylome is responsive to our environment, but its dynamics remain underexplored. We investigated the temporal changes to DNA methylation (DNAme) in relation to recovery from a shift work disorder (SWD) by performing a paired epigenome-wide analysis in an occupational cohort of 32 shift workers (25 men, age = 43.8 ± 8.8 years, 21 SWD cases). We found that the effect of vacation on DNAme was more prominent in the SWD-group as compared to controls, with respect to the amount of significantly differentially methylated positions (DMPs; P_unadj < 0.05) 6.5 vs 3.7%, respectively. The vast majority (78%) of these DMPs were hypomethylated in SWD but not in controls (27%) during the work period. The Gene Ontology Cellular component "NMDA glutamate receptor" (P_FDR < 0.05) was identified in a pathway analysis of the top 30 genes in SWD. In-depth pathway analyses revealed that the Reactome pathway "CREB phosphorylation through the activation of CaMKII" might underlie the recovery. Furthermore, three DMPs from this pathway, corresponding to GRIN2C, CREB1, and CAMK2B, correlated with the degree of recovery (P_unadj < 0.05). Our findings provide evidence for the dynamic nature of DNAme in relation to the recovery process from a circadian disorder, with biological relevance of the emerging pathways.

Prevalence of Probable Shift Work Disorder in Non-Standard Work Schedules and Associations with Sleep, Health and Safety Outcomes: A Cross-Sectional Analysis

PURPOSE

We aimed to estimate the prevalence of probable shift work disorder (pSWD) in a representative sample of Australian workers and identify sleep, health and safety correlates.

PATIENTS AND METHODS

In 2019, data were collected from working respondents as part of a cross-sectional national sleep health survey conducted online (n=964 total; n=448 individuals on non-standard work schedules). We established the prevalence of pSWD according to International Classification of Sleep Disorders criteria (ICSD-R, ICSD-2 and ICSD-3). Poisson regression was used to determine crude and adjusted prevalence association (prevalence ratio, PR) of pSWD with sleep, health and safety outcomes.

RESULTS

Overall prevalence of pSWD in workers on non-standard work schedules was 10.5%, ranging from 9.6% in early morning workers to 12.7% in rotating shift workers. In adjusted models, workers who met the criteria for pSWD were 1.8 times more likely to report both depression/bipolar disorder, and anxiety/panic disorder, and 1.7 times more likely to report work errors due to a sleep problem.

CONCLUSION

The prevalence of pSWD in employees engaged in non-standard work schedules is influenced by selection of factors used to quantify pSWD, including sleep/wake patterns. Higher likelihoods of mental health problems and workplace errors in those with pSWD highlight the importance of intervention and management of this under-recognised sleep disorder.

Health Risks and Potential Predictors of Fatigue and Sleepiness in Airline Cabin Crew

Background: Aviation pilots and cabin crew regularly undertake shift work, and may experience circadian disruption, restricted sleep, sleepiness and impaired health. Research on aviation fatigue and sleepiness has focused on pilots, with less being known about cabin crew. This study aimed to identify likely predictors of fatigue, sleepiness, shift work disorder (SWD) and depression in cabin crew. Methods: An online anonymous survey was distributed to active cabin crew around the world. It measured sleepiness, fatigue, and screened for insomnia, depression and SWD. Information on individuals’ habits and work schedules were collected. Results: 930 valid responses were analysed. 63.5% of the sample had abnormal levels of fatigue and 46.9% experienced excessive daytime sleepiness. 68.0% were at risk for SWD, 57.7% screened positive for insomnia, and 40.0% for depression. Caffeine and use of alcohol and drugs for sleep were independently associated with insomnia and SWD (p < 0.05), whereas, type of route (international, domestic, both) and number of duty days per week predicted fatigue (p < 0.05). Conclusions: Cabin crew had a high prevalence of fatigue, sleepiness and elevated risk for SWD, insomnia and depression. Many cabin crew engaged in behaviours detrimental to good sleep hygiene, highlighting targets for future interventional studies.

Self-reported seasonality is strongly associated with chronotype and weakly associated with latitude

The aim of this study was to investigate the association between self-reported seasonality, i.e., seasonal variations in mood and related behavior, and chronotype, and between self-reported seasonality and home address' latitude. Data were collected from an online questionnaire with 45,338 participants. Seasonality and chronotype were measured with the Global Seasonality Score (GSS) and the Composite Scale of Morningness, respectively. The participants were categorized into extreme morning types, moderate morning types, intermediate types, moderate evening types, and extreme evening types. Furthermore, participants were categorized depending on home address' latitude. Data were analyzed with chi-square tests and logistic regression analyses adjusting for sex, age, marital status, level of education, and children living at home. Results showed that high seasonality (GSS 11+) was found in 20.9%. The prevalence dose-dependency ranged from 12.2% in extreme morning types to 42.6% in extreme evening types (adjusted OR = 4.21, CI = 3.27-5.41). The prevalence was higher in participants living in North-Norway (latitude from 65 to 71⁰N) versus South-Norway (latitude from 58 to 65⁰N) (23.8% versus 20.7%; adjusted OR = 1.18, CI = 1.08-1.28). When comparing the northernmost (69-71⁰N) to the southernmost (58-59⁰N) counties of Norway, the association was stronger (24.9% versus 18.7%; adjusted OR = 1.37, CI = 1.20-1.56). Among the adjusting variables, high seasonality was associated with female sex, younger age, being unmarried, low level of education, and not having children living at home. In conclusion, about one in five Norwegians reported high seasonality. High seasonality was strongly associated with late chronotype (being an evening type) and weakly associated with living in the north (high latitude).

The effects of bright light treatment on subjective and objective sleepiness during three consecutive night shifts among hospital nurses - a counter-balanced placebo-controlled crossover study

Objectives The objective was to investigate effects of timed bright light treatment on subjective and objective measures of sleepiness during three consecutive night shifts among hospital nurses. Methods Thirty-five nurses were exposed to bright light (10,000 lux) and red dim light (100 lux) during three consecutive night shifts in a counter-balanced crossover trial lasting nine days, which included three days before and three days after the three night shifts. Light exposure for 30 minutes was scheduled between 02:00-03:00 hours on night 1, and thereafter delayed by one hour per night in order to delay the circadian rhythm. Subjective sleepiness was measured daily (heavy eyelids, reduced performance) and every second hour while awake (Karolinska Sleepiness Scale, KSS). Objective sleepiness (Psychomotor Vigilance Task, PVT) was measured at 05:00 hours during each night shift. Beyond nocturnal light exposure on the night shifts, no behavioral restrictions or recommendations were given at or off work. Results Bright light treatment significantly reduced heavy eyelids during night shifts. However, results on KSS and PVT were unaffected by bright light. There were no differences in subjective sleepiness during the three days following the night shifts. Conclusions This bright light treatment protocol did not convincingly reduce sleepiness among nurses during three consecutive night shifts. Nor did bright light impede the readaptation back to a day-oriented rhythm following the night shift period. Too few consecutive night shifts, inappropriate timing of light, and possible use of other countermeasures are among the explanations for the limited effects of bright light in the present study.

Employees with shift work disorder experience excessive sleepiness also on non-work days: a cross-sectional survey linked to working hours register in Finnish hospitals

A considerable proportion of shift workers have work schedule-related insomnia and/or excessive sleepiness, a phenomenon described as shift work disorder (SWD). There is yet a lack of evidence on whether or not employees recover from symptoms of SWD between work shifts. We studied whether SWD and its subtypes are associated with insomnia and excessive sleepiness during weekly non-work days and with 24-h sleep time. Hospital employees answered a survey on SWD, insomnia and excessive sleepiness on weekly non-work days, and 24-h sleep. To identify shift workers with night shifts (n=2,900, 18% with SWD) and SWD, we linked survey responses to employers' register on working hours. SWD included three subtypes: insomnia only (SWD-I, 4%, n=102), excessive sleepiness only (SWD-Es, 8%, n=244), and both insomnia and excessive sleepiness (SWD-IEs, 6%, n=183). Based on regression analyses, SWD was associated with excessive sleepiness on non-work days (OR: 1.42, 95% CI: 1.07-1.88) and with insomnia on non-work days (0.53, 0.31-0.91). SWD-I was associated with excessive sleepiness on non-work days (2.25, 1.31-3.87) and with shorter sleep (7-7.5 h: 1.96, 1.06-3.63; ≤6.5h: 2.39, 1.24-4.59; reference: ≥8 h). The results suggest that especially employees with SWD-I may need longer time to overcome excessive sleepiness than allowed by their roster.

Sleep quality, occupational factors, and psychomotor vigilance performance in the U.S. Navy sailors

Study Objectives

This field study (a) assessed sleep quality of sailors on the U.S. Navy (USN) ships while underway, (b) investigated whether the Pittsburgh Sleep Quality Index (PSQI) scores were affected by occupational factors and sleep attributes, and (c) assessed whether the PSQI could predict impaired psychomotor vigilance performance.

Methods

Longitudinal field assessment of fit-for-duty USN sailors performing their underway duties (N = 944, 79.0% males, median age 26 years). Participants completed questionnaires, wore actigraphs, completed logs, and performed the wrist-worn 3-min Psychomotor Vigilance Task (PVT).

Results

Sailors slept on average 6.60 ± 1.01 h/day with 86.9% splitting their sleep into more than one episode/day. The median PSQI Global score was 8 (interquartile range [IQR] = 5); 80.4% of the population were classified as “poor sleepers” with PSQI scores &gt;5. PSQI scores were affected by sailor occupational group, rank, daily sleep duration, and number of sleep episodes/day. Sleep quality showed a U-shape association with daily sleep duration due to the confounding effect of split sleep. Sailors with PSQI scores &gt;9 had 21.1% slower reaction times (p &lt; 0.001) and 32.8%–61.5% more lapses combined with false starts (all p &lt; 0.001) than sailors with PSQI scores ≤9. Compared to males and officers, females and enlisted personnel had 86% and 23% higher risk, respectively, of having PSQI scores &gt;9. Sailors in the PSQI &gt; 9 group had more pronounced split sleep.

Conclusions

Working on Navy ships is associated with elevated PSQI scores, a high incidence of poor sleep, and degraded psychomotor vigilance performance. The widely used PSQI score&gt;5 criterion should be further validated in active-duty service member populations.

Evaluating the quality and duration of sleep using actigraphy in petroleum industry shift workers

INTRODUCTION

Increased use of shift work has led to more and more people working outside a traditional daytime schedule. Currently, approximately 20% of the labor force in developed countries is shift workers. Shift work can have devastating effects on employees' quality of life and sleep, leading to negative consequences for individuals and their families. This study evaluates the effect of different shift schedules (seven days/seven nights, fixed-day or fixed-night, and stand-by shift) on the sleep of oil rig shift workers.

PARTICIPANTS AND METHODS

In this cross-sectional study, 43 offshore workers from the National Iranian Drilling Company were enrolled. Subjects were asked to complete a questionnaire package consisting of the Epworth Sleepiness scale and Pittsburgh Sleep Quality Index (PSQI). Changes in sleep patterns were measured using actigraphy for different shift schedules.

RESULTS

The mean age of the participants was 35.9 ± 7.9 years and the mean tenure with the drilling company was 10 ± 6.8 years. The mean total sleep time was 353 ± 58 min. The seven day/seven night shift workers had less total sleep time than the other three groups of shift workers. The mean PSQI and Epworth Sleepiness scale scores were 6.77 ± 3.1 and 7.49 ± 4.3, respectively. Twelve shift workers (27%) were diagnosed with shift work disorder in the current study and 31 participants had poor sleep quality according to PSQI score (≥5).

CONCLUSION

Poor sleep quality is common in oil rig shift workers. Further research is needed to evaluate sleep problems in oil rig shift workers.

Are cognitive variables that maintain insomnia also involved in shift work disorder?

OBJECTIVE

Shift Work Disorder (SWD) is explained mainly by a misalignment between the sleep schedule and the circadian rhythm. However, the possible role of cognitive variables in maintaining SWD remains unknown. Therefore, the objective of this study is to evaluate whether cognitive variables known to maintain insomnia in day workers might also be involved in perpetuating SWD.

DESIGN

Cross-sectional.

SETTING

Sleep laboratory.

PARTICIPANTS

Twenty-five shift workers diagnosed with SWD (84% females; mean age = 35.9) and 22 shift workers who are good sleepers (91% females; mean age = 34.1).

MEASUREMENTS

The participants completed a sleep diary for two weeks, answered questionnaires, and underwent the Harvey's semistructured interview and the catastrophizing procedure. Data from the catastrophizing procedure underwent a content analysis.

RESULTS

Compared with good sleepers, shift workers with SWD reported experiencing more thoughts that keep them awake, more presleep cognitive arousal, more dysfunctional beliefs related to worries and helplessness, and more selective attention toward worries and noises. However, the two groups did not differ on the tendency to catastrophize about difficulties falling asleep. Furthermore, 12 catastrophizing themes were identified in the entire sample, the most frequently endorsed being "sleepiness and energy" and "performance at work."

CONCLUSIONS

The results suggest that cognitive variables may play a role in maintaining SWD. Finally, worries that interfere with sleep in shift workers are related to their work context.

Shift work sleep disorders and associated factors among nurses at federal government hospitals in Ethiopia: a cross-sectional study

OBJECTIVE

The current study was conducted to assess the prevalence and associated factors of shift work sleep disorder among nurses working at Ethiopian federal government hospitals in Addis Ababa.

METHODS

An institutional-based, cross-sectional study was conducted from April to June 2018 using self-administered structured questionnaires. Computer-generated simple random sampling technique was used to select a total of 422 nurses as study participants. The International Classification of Sleep Disorders - Third Edition, Bargen Insomnia Scale and/or Epworth Sleepiness Scale were used to measure the outcome shift work sleep disorder. Descriptive statistics and bivariate and multivariate binary logistic regression were used. OR with 95% CI was used to measure the strength of association, and a p value <0.05 was considered statistically significant in multivariate analysis.

RESULTS

About a quarter (25.6%) of the study participants have shift work sleep disorder. The average number of nights per month for the last 1 year (adjusted OR=6.3, 95% CI 3.513 to 12.35) and working in three-shift rotation (adjusted OR=3.1, 95% CI 1.68 to 5.83) were significantly associated with shift work sleep disorder.

CONCLUSION

A quarter of shift worker nurses are suffering from shift work sleep disorder. The number of nights on average per month for the last 1 year and working in three-shift rotation were significantly associated with shift work sleep disorder. Shift working conditions should be improved to provide less stressful conditions for nurses, ensuring at the same time an appropriate quality of care over a 24-hour period. More studies are necessary to better highlight the burden of shift work on the health and well-being of both nurses and patients.

Prevalence of shift work disorder among hospital personnel: A cross-sectional study using objective working hour data

The prevalence of shift work disorder (SWD) has been studied using self-reported data and the International Classification of Sleep Disorders, Second Edition (ICSD-2) criteria. We examined the prevalence in relation to ICSD-2 and ICSD-3 criteria, work schedules and the number of non-day shifts (work outside 06:00-18:00 hours) using objective working-hours data. Secondly, we explored a minimum cut-off for the occurrence of SWD symptoms. Hospital shift workers without (n = 1,813) and with night shifts (n = 2,917) and permanent night workers (n = 84) answered a survey (response rate 69%) on SWD and fatigue on days off. The prevalence of SWD was calculated for groups with ≥1, ≥3, ≥5 and ≥7 monthly non-day shifts utilizing the working hours registry. ICSD-3-based SWD prevalence was 2.5%-3.7% (shift workers without nights), 2.6%-9.5% (shift workers with nights) and 6.0% (permanent night workers), depending on the cut-off of non-day shifts (≥7-1/month, respectively). The ICSD-2-based prevalence was higher: 7.1%-9.2%, 5.6%-33.5% and 16.7%, respectively. The prevalence was significantly higher among shift workers with than those without nights (p-values <.001) when using the cut-offs of ≥1-3 non-day shifts. Shift workers with nights who had ≥3 days with ICSD-3-based SWD symptoms/month more commonly had fatigue on days off (49.3%) than those below the cut-off (35.8%, p < .05). The ICSD-3 criteria provided lower estimates for SWD prevalence than ISCD-2 criteria, similarly to exclusion of employees with the fewest non-day shifts. The results suggest that a plausible cut-off for days with ICSD-3-based SWD symptoms is ≥3/month, resulting in 3%-6% prevalence of SWD.

Exploring the associations between shift work disorder, depression, anxiety and sick leave taken amongst nurses

This study aimed to evaluate the association between shift work disorder and mental health in hospital-based nurses. Staff completed an online survey comprising demographic questions, the Shift Work Disorder Questionnaire, Patient Health-9 and the General Anxiety Disorder-7 scale. Sick leave data were collected from archival records from the Human Resources Department. Two hundred and two nurses (95% female; age M = 35.28 years ± SD = 12) participated (42% of eligible staff). Those at high risk of shift work disorder had higher depression (M = 7.54 ± SD = 4.28 vs. M = 3.78 ± SD = 3.24; p < 0.001) and anxiety (M = 5.66 ± SD = 3.82 vs. M = 2.83 ± SD = 3.33, p < 0.001) compared to those at low risk. Linear regression models showed that being at high risk of shift work disorder was the most significant predictor of depression, explaining 18.8% of the variance in depression (R²  = 0.188, adjusted R²  = 0.184, F(1, 200) = 46.20, p < 0.001). Shift work disorder combined with the number of night shifts and alcoholic drinks on non-work days accounted for 49.7% of the variance in anxiety scores (R²  = 0.497, adjusted R²  = 0.453, F(3, 35) = 11.51, p < 0.001). Mean sick leave in those with high risk of shift work disorder was 136.17 hr (SD = 113.11) versus 103.98 hr (SD = 94.46) in others (p = 0.057). Depression and years of shift work accounted for 18.9% of the variance in sick leave taken (R²  = 0.189, adjusted R²  = 0.180, F(2, 175) = 20.36, p < 0.001). Shift work disorder is strongly associated with depression and anxiety, providing a potential target to improve mental health in shift workers. Depression, in turn, is a significant contributing factor to sick leave.

Working Time Society consensus statements: Psychosocial stressors relevant to the health and wellbeing of night and shift workers

This consensus report summarizes the negative impact of work-related psychosocial factors and job stressors on the health and wellbeing of shift workers. Psychosocial factors may (a) directly affect work schedules or (b) mediate or moderate relationships between work schedules, circadian factors, and health. In this paper, prominent psychosocial models (e.g. Job Strain and Effort-Reward Imbalance) are used to help assess detrimental effects, including pathophysiologic outcomes. Several studies indicate the psychosocial environment can be more problematic for shift workers compared to regular day workers. This is likely due to shift worker's experiencing greater risks of low job control, high physical work demands, lower support from supervisors, and greater levels of over-commitment. Workplace violence is another frequently encountered psychosocial stressor for shift workers more likely to be in regular contact with the general public, such as police officers, security personnel, professional drivers, and other service employees being at elevated risk. A large body of literature confirms night and irregular shift schedules increase risk for injury. Non-diurnal schedules can trigger and worsen such incidents, especially under unsafe conditions. The problem of workplace violence for shift workers, in terms of severity and consequences, is probably underestimated, especially when present among other occupational stressors. Practical considerations and recommendations for action to mitigate the detrimental effects of psychosocial stressors on night and shift workers are presented.

A distinctive DNA methylation pattern in insufficient sleep

Short sleep duration or insomnia may lead to an increased risk of various psychiatric and cardio-metabolic conditions. Since DNA methylation plays a critical role in the regulation of gene expression, studies of differentially methylated positions (DMPs) might be valuable for understanding the mechanisms underlying insomnia. We performed a cross-sectional genome-wide analysis of DNA methylation in relation to self-reported insufficient sleep in individuals from a community-based sample (79 men, aged 39.3 ± 7.3), and in relation to shift work disorder in an occupational cohort (26 men, aged 44.9 ± 9.0). The analysis of DNA methylation data revealed that genes corresponding to selected DMPs form a distinctive pathway: "Nervous System Development" (FDR P value < 0.05). We found that 78% of the DMPs were hypomethylated in cases in both cohorts, suggesting that insufficient sleep may be associated with loss of DNA methylation. A karyoplot revealed clusters of DMPs at various chromosomal regions, including 12 DMPs on chromosome 17, previously associated with Smith-Magenis syndrome, a rare condition comprising disturbed sleep and inverse circadian rhythm. Our findings give novel insights into the DNA methylation patterns associated with sleep loss, possibly modifying processes related to neuroplasticity and neurodegeneration. Future prospective studies are needed to confirm the observed associations.

Sleep and alertness in shift work disorder: findings of a field study

Purpose

Although shift work disorder (SWD) affects a major part of the shift working population, little is known about its manifestation in real life. This observational field study aimed to provide a detailed picture of sleep and alertness among shift workers with a questionnaire-based SWD, by comparing them to shift workers without SWD during work shifts and free time.

Methods

SWD was determined by a questionnaire. Questionnaires and 3-week field monitoring, including sleep diaries, actigraphy, the Karolinska Sleepiness Scale (KSS), EEG-based sleep recordings, and Psychomotor Vigilance Tasks (PVT), were used to study 22 SWD cases and 9 non-SWD workers.

Results

The SWD group had a shorter subjective total sleep time and greater sleep debt before morning shifts than the non-SWD group. Unlike the non-SWD group, the SWD group showed little compensatory sleep on days off. The SWD group had lower objective sleep efficiency and longer sleep latency on most days, and reported poorer relaxation at bedtime and sleep quality across all days than the non-SWD group. The SWD group’s average KSS-sleepiness was higher than the non-SWD group’s sleepiness at the beginning and end of morning shifts and at the end of night shifts. The SWD group also had more lapses in PVT at the beginning of night shifts than the non-SWD group.

Conclusions

The results indicate that SWD is related to disturbed sleep and alertness in association with both morning and night shifts, and to less compensatory sleep on days off. SWD seems to particularly associate with the quality of sleep.

Electronic supplementary material

The online version of this article (10.1007/s00420-018-1386-4) contains supplementary material, which is available to authorized users.

Migraine, tension-type headache and medication-overuse headache in a large population of shift working nurses: a cross-sectional study in Norway

OBJECTIVES

To investigate associations between different types of headaches and shift work.

DESIGN, PARTICIPANTS AND OUTCOME MEASURES

Nurses with different work schedules (day work, two-shift rotation, night work, three-shift rotation) participated in a cohort study with annual surveys that started in 2008/2009. In 2014 (wave 6), a comprehensive headache instrument was included in the survey, in which 1585 nurses participated. Headaches were assessed according to the International Classification of Headache Disorders IIIb. Frequent headache (≥1 day per month), migraine, tension-type headache, chronic headache (headache >14 days per month) and medication-overuse headache (chronic headache + acute headache medication ≥10 days last month) comprised the dependent variables. Adjusted (for sex, age, percentage of full-time equivalent, marital status, children living at home) logistic regression analyses were conducted with work schedule, number of night shifts worked last year, number of quick returns (<11 hours in-between shifts) last year, shift work disorder and insomnia disorder as predictors.

RESULTS

Frequent headache, migraine and chronic headache were associated with shift work disorder (OR 2.04, 95% CI 1.62 to 2.59; 1.60, 1.21 to 2.12; 2.45, 1.25 to 4.80, respectively) and insomnia disorder (OR 1.79, 95% CI 1.43 to 2.23; 1.55, 1.18 to 2.02; 3.03, 1.54 to 5.95, respectively), but not with work schedule, number of night shifts or number of quick returns. Tension-type headache was only associated with >20 night shifts last year (OR 1.41, 95% CI 1.07 to 1.86). Medication-overuse headache was only associated with insomnia disorder (OR 7.62, 95% CI 2.48 to 23.41).

CONCLUSIONS

We did not find any association between different types of headaches and work schedule. However, tension-type headache was associated with high number of night shifts. Nurses with sleep disorders (insomnia disorder and shift work disorder) reported higher prevalence of frequent headaches, migraine, chronic headache and medication-overuse headache (only insomnia) compared with nurses not having insomnia disorder and shift work disorder, respectively.

Individual vulnerability to insomnia, excessive sleepiness and shift work disorder amongst healthcare shift workers. A systematic review

Shift workers often experience reduced sleep quality, duration and/or excessive sleepiness due to the imposed conflict between work and their circadian system. About 20-30% of shift workers experience prominent insomnia symptoms and excessive daytime sleepiness consistent with the circadian rhythm sleep disorder known as shift work disorder. Individual factors may influence this vulnerability to shift work disorder or sleep-related impairment associated with shift work. This paper was registered with Prospero and was conducted using recommended standards for systematic reviews and meta-analyses. Published literature that measured sleep-related impairment associated with shift work including reduced sleep quality and duration and increased daytime sleepiness amongst healthcare shift workers and explored characteristics associated with individual variability were reviewed. Fifty-eight studies were included. Older age, morning-type, circadian flexibility, being married or having children, increased caffeine intake, higher scores on neuroticism and lower on hardiness were related to a higher risk of sleep-related impairment in response to shift work, whereas physical activity was a protective factor. The review highlights the diverse range of measurement tools used to evaluate the impact of shift work on sleep. Use of standardised and validated tools would enable cross-study comparisons. Longitudinal studies are required to establish causal relationships between individual factors and the development of shift work disorder.