Shift work and the assessment and management of shift work disorder (SWD)

Differences between fixed day shift nurses and rotating and irregular shift nurses in work-related musculoskeletal disorders: A literature review and meta-analysis

OBJECTIVES

Work-related musculoskeletal disorders (WMSDs) are common occupational injuries for nurses. Furthermore, rotating and irregular shift work may exacerbate muscle tension and pain in nurses. The objective of this study was to examine the differences between fixed day shift (FDS) nurses and rotating and irregular shift (RS + IS) nurses in WMSDs using a systematic literature review and meta-analysis.

METHODS

Databases including PubMed, CINAHL, Cochrane Library, EBSCOhost, and Google Scholar were searched for relevant studies published between 2010 and 2020 using the target keywords.

RESULTS

This study obtained data on a total of 18 199 nurses, among which 12 786 comprised the RS + IS group and 5413 constituted the FDS group. The result of the heterogeneity test was Q = 79.27 (P < .001) and I squared = 57.11%, indicating that heterogeneity existed among the studies. Subgroup analyses were also conducted with four groups: neck pain (n = 1818), shoulder and upper limb pain (n = 2525), back pain (n = 11 962), and hip and lower limb pain (n = 1894). Significant differences were found between the RS + IS group and the FDS group with regard to back pain, with the forest plot presenting an odds ratio equaling 1.40 (95% CI: 1.19-1.64, P < .001).

CONCLUSIONS

This meta-analysis indicated that RS + IS nurses are more likely to experience back pain associated with WMSD than are FDS nurses. The results can serve as a reference to the clinical management for work improvement and thereby reduce or prevent the adverse effects of rotating and irregular shift work on back pain experienced by nurses.

Body fat indicators for cardiometabolic risk screening among shift workers

BACKGROUND

In view of the costly methods currently available for the assessment of body adiposity, anthropometric obesity indicators have proven effective in predicting cardiovascular risk.

OBJECTIVE

To investigate the discriminatory power of body fat indicators for cardiovascular risk screening among shift workers.

METHODS

Cross-sectional study with male employees of an iron ore extraction company. The predictive power of body fat indicators relative to cardiovascular risk was analyzed based on the Framingham risk score and metabolic syndrome by means of receiver operating characteristic curves, sensitivity, specificity, positive and negative predictive values, area under the receiver operating characteristic curve and Youden's index.

RESULTS

The prevalence of cardiovascular risk was 14.2% in the metabolic syndrome risk model. According to the Framingham score, 95.0%, 4.1% and 0.9% of the participants exhibited low, moderate and high risk, respectively. All the analyzed body fat indicators exhibited satisfactory discriminatory power for the tested cardiovascular risk models.

CONCLUSION

Waist-height ratio exhibited the highest ability to predict cardiometabolic risk in both risk models.

The Development of a Sleep Intervention for Firefighters: The FIT-IN (Firefighter's Therapy for Insomnia and Nightmares) Study

Background: Firefighters are vulnerable to irregular sleep patterns and sleep disturbance due to work characteristics such as shift work and frequent dispatch. However, there are few studies investigating intervention targeting sleep for firefighters. This preliminary study aimed to develop and test a sleep intervention, namely FIT-IN (Firefighter’s Therapy for Insomnia and Nightmares), which was based on existing evidence-based treatment tailored to firefighters in consideration of their occupational characteristics. Methods: This study implemented a single-group pre-post study design, utilizing an intervention developed based on brief behavior therapy for insomnia with imagery rehearsal therapy components. FIT-IN consisted of a total of three sessions (two face-to-face group sessions and one telephone session). Participants were recruited from Korean fire stations, and a total of 39 firefighters participated. Participants completed a sleep diary for two weeks, as well as the following questionnaires to assess their sleep and psychological factors: insomnia severity index (ISI), disturbing dream and nightmare severity index (DDNSI), Epworth sleepiness scale (ESS), depressive symptom inventory-suicidality subscale (DSI), and Patient Health Questionnaire-9 (PHQ-9). These questionnaires were administered before the first session and at the end of the second session. Results: The FIT-IN program produced improvements in sleep indices. There was a significant increase in sleep efficiency (p < 0.01), and a decrease in sleep onset latency, number of awakenings, and time in bed (p < 0.05), as derived from weekly sleep diaries. In addition, significant decreases were shown for insomnia (p < 0.001) and nightmare severity (p < 0.01). Conclusion: There were significant improvements in sleep and other clinical indices (depression, PTSD scores) when comparing pre-and post-intervention scores. FIT-IN may be a feasible and practical option in alleviating sleep disturbance in this population. Further studies will be needed to ascertain FIT-IN’s effectiveness.

Regulation of Olfactory Associative Memory by the Circadian Clock Output Signal Pigment-Dispersing Factor (PDF)

Dissociation between the output of the circadian clock and external environmental cues is a major cause of human cognitive dysfunction. While the effects of ablation of the molecular clock on memory have been studied in many systems, little has been done to test the role of specific clock circuit output signals. To address this gap, we examined the effects of mutations of Pigment-dispersing factor (Pdf) and its receptor, Pdfr, on associative memory in male and female Drosophila Loss of PDF signaling significantly decreases the ability to form associative memory. Appetitive short-term memory (STM), which in wild-type (WT) is time-of-day (TOD) independent, is decreased across the day by mutation of Pdf or Pdfr, but more substantially in the morning than in the evening. This defect is because of PDFR expression in adult neurons outside the core clock circuit and the mushroom body (MB) Kenyon cells (KCs). The acquisition of a TOD difference in mutants implies the existence of multiple oscillators that act to normalize memory formation across the day for appetitive processes. Interestingly, aversive STM requires PDF but not PDFR, suggesting that there are valence-specific pathways downstream of PDF that regulate memory formation. These data argue that the circadian clock uses circuit-specific and molecularly diverse output pathways to enhance the ability of animals to optimize responses to changing conditions.SIGNIFICANCE STATEMENT From humans to invertebrates, cognitive processes are influenced by organisms' internal circadian clocks, the pace of which is linked to the solar cycle. Disruption of this link is increasingly common (e.g., jetlag, social jetlag disorders) and causes cognitive impairments that are costly and long lasting. A detailed understanding of how the internal clock regulates cognition is critical for the development of therapeutic methods. Here, we show for the first time that olfactory associative memory in Drosophila requires signaling by Pigment-dispersing factor (PDF), a neuromodulatory signaling peptide produced only by circadian clock circuit neurons. We also find a novel role for the clock circuit in stabilizing appetitive sucrose/odor memory across the day.

Association for combined exposure to job strain, shift work on mental health among Chinese railway workers: a cross-sectional study

OBJECTIVES

The aim of this study was to assess the effects of coexposure to job strain and shift work on mental health in railway workers.

DESIGN

Cross-sectional study.

SETTING

One Railway Bureau Group in China.

PARTICIPANTS

A total of 1270 front-line railway workers.

OUTCOME MEASURES

The Symptom Checklist-90-Revised questionnaire was used to measure general mental health. Job strain variables were derived from the Job Content Questionnaire. Based on the records of the work schedule 3 months prior to the survey, the following three shift types were identified: fixed day, fixed night and rotating night shifts. Risks associated with mental health were assessed by carrying out logistic regression analysis which was adjusted for age, job tenure, smoking and exercise. Additionally, a crossover analysis was employed for the combined effects.

RESULTS

High levels of job strain were linked to a higher risk of poor mental health (OR=1.53, 95% CI: 1.10 to 2.11). After adjusting for confounding factors, night shifts and rotating night shifts were significant risk factors for mental health (OR=2.21, 95% CI: 1.60 to 3.07; OR=2.36, 95% CI: 1.73 to 3.22). Compared with participants who experienced a low level of job strain and day shifts, those with a high level of job strain and who worked rotating shifts were at the highest risk of poor mental health (OR=4.68, 95% CI: 2.91 to 8.04), whereas the influence of a low level of job strain and rotating night shifts was not statistically significant.

CONCLUSION

Job strain and night shifts among workers were associated, both independently and in combination, with an increased risk of poor mental health. Our data suggest that job strain contributes to the risk of poor mental health by means of a combined effect with shift work.

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.

Night shift work and immune response to the meningococcal conjugate vaccine in healthy workers: a proof of concept study

BACKGROUND

It is well-established that sleep regulates immune functions. Immunological functions are dependent on circadian rhythms and regular sleep as both have an impact on the magnitude of immune responses following antigenic challenge (eg, in vaccination). Here we investigated whether nocturnal shift work can influence post-vaccination response.

METHODS

Thirty-four healthy workers (23 females) working either nocturnal or diurnal shifts (17 in each group) received the meningococcal C meningitis vaccine. Sleep was recorded polysomnographically (PSG) and with actigraphy. Humoral and cellular responses were assessed after vaccination.

RESULTS

Night workers showed decreased N3 stage and REM sleep duration, increased inflammatory mediators (TNF-α and IL-6 levels), and a weak specific humoral response to vaccination associated with reduced CD4 T lymphocytes, reduced plasmacytoid dendritic cells, reduced prolactin levels, increased T_Reg and increased IL-10 levels. In addition, the decrease in total sleep time and circadian rhythm alterations were associated with a reduced humoral response post-vaccination.

CONCLUSIONS

Our findings provide novel evidence concerning immune alterations of shift work on workers' health based on real-life circumstances. In association with circadian components, sufficient sleep time and rhythm synchronization were important for the development of the Ag-specific immune response, suggesting that the humoral response to vaccination may be impaired in individuals with chronic sleep restriction and circadian misalignment.

Dose-response association of sleep quality with anxiety symptoms in Chinese rural population: the Henan rural cohort

BACKGROUND

The epidemiological evidence on the association of sleep quality on anxiety symptoms has been inconclusive. This study aimed to explore the association between sleep quality and anxiety symptoms in rural Chinese population and investigate whether age, lifestyles, and chronic diseases modified this association.

METHODS

A total of 27,911 participants aged 18-79 years from the Henan Rural Cohort Study were included in the study. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) scale. Poor sleep quality was defined as PSQI ≥6. Anxiety symptoms were evaluated with the two-item generalized anxiety disorder scale (GAD-2). Individual with score ≥ 3 was viewed as having anxiety symptoms. Logistic regression and restricted cubic spline were conducted to examine the association of sleep quality with anxiety symptoms.

RESULTS

Altogether, 6087 (21.80%) participants were poor sleepers and 1557 (5.58%) had anxiety symptoms. The odds of anxiety were increased with increment of PSQI score after fitting restricted cubic splines. The poor sleep quality was associated with a higher possibility of anxiety symptoms [odd ratio (OR): 4.60, 95% confidence interval (CI): 3.70-5.72] in men, and (OR: 3.56, 95% CI: 3.10-4.09) in women for multivariable analysis. Further, stratified analyses showed that the effect of sleep quality on anxiety symptoms could be modified by age, marital status, smoking status, drinking status, hypertension, and type 2 diabetes mellitus.

CONCLUSIONS

A dose-response association between PSQI score and anxiety symptoms was found. In addition, the relationship between poor sleep quality and greater anxiety symptoms was observed in this rural population, especially in participants aged ≥60 years and those with unhealthy habits or had a chronic disease.

TRIAL REGISTRATION

The trial was prospectively registered on July 6, 2015 and available online at ClinicalTrials.gov ID: ChiCTR-OOC-15006699 .

Analyzing the effect of social interaction on job demands and health in the example of flexible shiftwork

In the literature, shiftwork-related stress is often connected with health complaints. However, it has been shown that these are not equally distributed. Further reasons must exist as to why stress resulting from shiftwork only affects health in some cases. In a study with 653 employees working in highly flexible shiftwork conditions, an examination was made of the factors affecting the relationship between job demands and health status. The results show that satisfaction with leadership influences whether unevenly distributed work and time pressure have a significant impact on health. The factor of other people living in the household significantly influences whether time pressure and emotional stress lead to health complaints. The study concluded that the impact of social interaction as a resource is not limited to the workplace. Social interaction, as a personal resource, can be helpful in both the professional and private spheres.

Improving fatigue risk management in healthcare: A scoping review of sleep-related/ fatigue-management interventions for nurses and midwives (reprint)

BACKGROUND

Nurses and midwives make up almost 50% of the global healthcare shift working workforce. Shift work interferes with sleep and causes fatigue with adverse effects for nurses' and midwives' health, as well as on patient safety and care. Where other safety-critical sectors have developed Fatigue Risk Management Systems, healthcare is behind the curve; with published literature only focussing on the evaluation of discreet sleep-related/fatigue-management interventions. Little is known, however, about which interventions have been evaluated for nurses and midwives. Our review is a critical first step to building the evidence-base for healthcare organisations seeking to address this important operational issue.

OBJECTIVES

We address two questions: (1) what sleep-related/fatigue-management interventions have been assessed in nurses and midwives and what is their evidence-base? and (2) what measures are used by researchers to assess intervention effectiveness?

DESIGN AND DATA SOURCES

The following databases were searched in November, 2018 with no limit on publication dates: MEDLINE, PsychINFO and CINAHL.

REVIEW METHODS

We included: (1) studies conducted in adult samples of nurses and/or midwives that had evaluated a sleep-related/fatigue-management intervention; and (2) studies that reported intervention effects on fatigue, sleep, or performance at work, and on measures of attention or cognitive performance (as they relate to the impact of shift working on patient safety/care).

RESULTS

The search identified 798 potentially relevant articles, out of which 32 met our inclusion criteria. There were 8619 participants across the included studies and all were nurses (88.6% female). We did not find any studies conducted in midwives nor any studies conducted in the UK, with most studies conducted in the US, Italy and Taiwan. There was heterogeneity both in terms of the interventions evaluated and the measures used to assess effectiveness. Napping could be beneficial but there was wide variation regarding nap duration and timing, and we need to understand more about barriers to implementation. Longer shifts, shift patterns including nights, and inadequate recovery time between shifts (quick returns) were associated with poorer sleep, increased sleepiness and increased levels of fatigue. Light exposure and/or light attenuation interventions showed promise but the literature was dominated by small, potentially unrepresentative samples.

CONCLUSIONS

The literature related to sleep-related/fatigue-management interventions for nurses and midwives is fragmented and lacks cohesion. Further empirical work is warranted with a view to developing comprehensive Fatigue Risk Management Systems to protect against fatigue in nurses, midwives, and other shift working healthcare staff.

Shift Work Sleep Disorder and Night Shift Work Significantly Impair Erectile Function

OBJECTIVES

Here we examine the association between shift work sleep disorder (SWSD) and erectile dysfunction (ED) in shift workers.

METHODS

Men presenting to a single andrology clinic between January 2014 and July 2017 completed validated questionnaires: International Index of Erectile Function (IIEF), Patient Health Questionnaire-9 (PHQ-9), and the nonvalidated SWSD Questionnaire. Men were also asked about shift work schedule, comorbidities, phosphodiesterase 5 (PDE5) inhibitor use, and testosterone use. Serum total testosterone values were determined for each visit. Linear regression was performed controlling for testosterone use, testosterone levels, PDE5 inhibitor use, age, and comorbidities to determine the effect of SWSD on ED as assessed using the IIEF.

RESULTS

Of the 754 men completing questionnaires, 204 reported nonstandard shift work (begins before 7 am or after 6 pm, regularly extends out of that frame, or rotates frequently) and 48 were found to have SWSD using a screening questionnaire. Nonstandard shift work alone did not result in worse IIEF-EF scores (P = .31), but those who worked nonstandard shifts and had SWSD demonstrated IIEF-EF scores 2.8 points lower than men without SWSD (P < .01). When assessing for the type of shift work performed, men who worked night shifts had IIEF-EF scores 7.6 points lower than men who worked during the day or evening (P < .01). Testosterone use improved IIEF-EF scores for men with SWSD by 2.9 points, ameliorating the effect of SWSD on ED. However, baseline testosterone levels were not associated with worse erectile function in this cohort.

CONCLUSION

Men with SWSD have worse erectile function, with men who work night shifts having even poorer erectile function. These findings suggest that circadian rhythm disturbance may significantly impact erectile function. While testosterone therapy may partly reverse the effects of SWSD, shift work is a potential risk factor for ED and should be assessed for as part of the evaluation of men with ED. Rodriguez KM, Kohn TP, Kohn JR, et al. Shift Work Sleep Disorder and Night Shift Work Significantly Impair Erectile Function. J Sex Med 2020;17:1687-1693.

Are prolonged sitting and sleep restriction a dual curse for the modern workforce? a randomised controlled trial protocol

INTRODUCTION

Prolonged sitting and inadequate sleep are a growing concern in society and are associated with impairments to cardiometabolic health and cognitive performance. However, the combined effect of prolonged sitting and inadequate sleep on measures of health and cognitive performance are unknown. In addition, the circadian disruption caused by shiftwork may further impact workers' cardiometabolic health and cognitive performance. This protocol paper outlines the methodology for exploring the impact of simultaneous exposure to prolonged sitting, sleep restriction and circadian disruption on cardiometabolic and cognitive performance outcomes.

METHODS AND ANALYSIS

This between-subjects study will recruit 208 males and females to complete a 7-day in-laboratory experimental protocol (1 Adaptation Day, 5 Experimental Days and 1 Recovery Day). Participants will be allocated to one of eight conditions that include all possible combinations of the following: dayshift or nightshift, sitting or breaking up sitting and 5 hour or 9 hour sleep opportunity. On arrival to the laboratory, participants will be provided with a 9 hour baseline sleep opportunity (22:00 to 07:00) and complete five simulated work shifts (09:00 to 17:30 in the dayshift condition and 22:00 to 06:30 in the nightshift condition) followed by a 9 hour recovery sleep opportunity (22:00 to 07:00). During the work shifts participants in the sitting condition will remain seated, while participants in the breaking up sitting condition will complete 3-min bouts of light-intensity walking every 30 mins on a motorised treadmill. Sleep opportunities will be 9 hour or 5 hour. Primary outcome measures include continuously measured interstitial blood glucose, heart rate and blood pressure, and a cognitive performance and self-perceived capacity testing battery completed five times per shift. Analyses will be conducted using linear mixed models.

ETHICS AND DISSEMINATION

The CQUniversity Human Ethics Committee has approved this study (0000021914). All participants who have already completed the protocol have provided informed consent. Study findings will be disseminated via scientific publications and conference presentations.

TRIAL REGISTRATION DETAILS

This study has been registered on Australian New Zealand Clinical Trials Registry (12619001516178) and is currently in the pre-results stage.

A High-Protein Meal during a Night Shift Does Not Improve Postprandial Metabolic Response the Following Breakfast: A Randomized Crossover Study with Night Workers

The aim of this study was to compare the acute effect of a high-protein/moderate carbohydrate (HP-MCHO) versus low-protein/high-carbohydrate (LP-HCHO) meal served at night on the postprandial metabolic response of male night workers the following breakfast. A randomized crossover study was performed with 14 male night workers (40.9 ± 8.9 years old; 29.1 ± 5.3 kg/m²). Participants underwent two different isocaloric dietary conditions at 1:00 h of the night shift: HP-MCHO (45 en% carbohydrate, 35 en% protein and 20 en% fat) and LP-HCHO (65 en% carbohydrate, 15 en% protein and 20 en% fat). Postprandial capillary glucose levels were determined immediately before the intake of the test meal and 30, 60, 90 and 120 min after the end of the meal. At the end of the work shift (6:30 h), participants received a standard breakfast and postprandial levels of glucose, insulin and triglycerides were determined immediately before and then every 30 min for 2 h (30, 60, 90 and 120 min). Higher values of capillary glucose were found after the LP-HCHO condition compared to the HP-MCHO condition (area under the curve (AUC) = 119.46 ± 1.49 mg/dL × min and 102.95 ± 1.28 mg/dL × min, respectively; p < 0.001). For the metabolic response to standard breakfast as the following meal, no significant differences in glucose, insulin, triglyceride, and HOMA-IR levels were found between interventions. A night meal with a higher percentage of protein and a lower percentage of carbohydrate led to minor postprandial glucose levels during the night shift but exerted no effect on the metabolic response of the following meal. This trial was registered at ClinicalTrials.gov as NCT03456219.

Pregnancy disorders in female workers at the industrial area of Sidoarjo, Indonesia

Background: The number of female workers in Indonesia has increased and female workers have been discovered to be very vulnerable to several hazards and health problems in the workplace environment linked to their menstrual cycle and pregnancy. Therefore, this study was conducted to analyze risk factors associated with pregnancy disorders in female workers. Design and Methods: The research was conducted through the use of a cross-sectional design with 307 female workers using simple random sampling. Furthermore, a descriptive analysis was conducted to describe the conditions of the respondents during pregnancy to childbirth process. Results: The results showed 45% of respondents had pregnancy disorders, 16% had miscarriages, and despite the fact most of the prenatal care processes was assisted by doctors or midwives, 2.6% of the respondents consulted Traditional Birth Attendants, who were also recorded and was found to account for 2.9% of the deliveries. Moreover, the risk factors associated with pregnancy disorders include vibrations (P=0.004), irritants (P=0.002) and repetitive works (P=0.009). Conclusions: It is recommended that companies should provide maternal and child health protection and control for any risk associated with female workers.

Cognitive functions of shift workers: paramedics and firefighters - an electroencephalography study

Introduction. Working shifts has a negative impact on employee health and cognitive efficiency. The purpose of this study was to investigate the impact of shift work on cognitive functions - attention and working memory - using both behavioural and electrophysiological measures. Methods. The study was carried out on a group of 34 shift employees (18 paramedics, 16 firefighters) and on 17 day workers. Participants performed the attention network test and the N-back task with two conditions (1-back, 2-back) while the electroencephalography signal was recorded. Results. Observations included a higher amplitude of the P200 potential in paramedics (compared to the control group), a higher amplitude of the P300 potential after work than on a day off and the lowest increase in power in the θ band after the night shift. In firefighters, lower α desynchronization and lower synchronization in the α/β band were observed after a 24-h shift. Paramedics and firefighters had longer reaction times (N-back task). Conclusions. The results suggest that paramedics experience problems with sustained attention. Paramedics process visual stimuli in a different way; after a night shift, performing the tasks required more engagement of cognitive resources. For firefighters, a decrease in visual attention functions and cognitive inhibition was observed.

Cognitive behavioural therapy interventions for insomnia among shift workers: RCT in an occupational health setting

INTRODUCTION

The aim of the study was to compare the effectiveness of cognitive behavioural therapy interventions for insomnia (CBT-I) to that of a sleep hygiene intervention in a randomized controlled design among shift workers. We also studied whether the features of shift work disorder (SWD) affected the results.

METHODS

A total of 83 shift workers with insomnia disorder were partially randomized into a group-based CBT-I, self-help CBT-I, or sleep hygiene control intervention. The outcomes were assessed before and after the interventions and at 6-month follow-up using questionnaires, a sleep diary, and actigraphy.

RESULTS

Perceived severity of insomnia, sleep-related dysfunctional beliefs, burnout symptoms, restedness, recovery after a shift, and actigraphy-based total sleep time improved after the interventions, but we found no significant differences between the interventions. Mood symptoms improved only among the group-based CBT-I intervention participants. Non-SWD participants had more mental diseases and symptoms, used more sleep-promoting medication, and had pronounced insomnia severity and more dysfunctional beliefs than those with SWD. After the interventions, non-SWD participants showed more prominent improvements than those with SWD.

CONCLUSIONS

Our results showed no significant differences between the sleep improvements of the shift workers in the CBT-I interventions and of those in the sleep hygiene control intervention. Alleviation of mood symptoms seemed to be the main added value of the group-based CBT-I intervention compared to the control intervention. The clinical condition of the non-SWD participants was more severe and these participants benefitted more from the interventions than the SWD participants did.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02523079.

The Influence of Shift Work on the Quality of Sleep and Executive Functions

Shift work is an inconsistent and atypical work schedule. This study aimed to investigate the influence of shift work on the Quality of Sleep (QOS) and Executive Functions (EF). Thirty shift workers and thirty day workers first completed a demographic questionnaire. They then were tested using the Pittsburgh Sleep Quality Index (PSQI) and EF tests, including the Corsi Block-Tapping Task (CBTT), Berg's Card Sorting Task (BCST), and the Continuous Performance Task (CPT). Results were subjected to non-parametric Chi-Square Tests, the Mann-Whitney U Test, and Independent T-Tests. Shift workers had significantly poorer sleep quality than day workers, which was shown in PSQI global scale (p = 0.001), sleep duration (p = 0.042), habitual sleep efficiency (p = 0.021), and sleep disturbance (p = 0.021). Concerning EF tests, shift workers performed significantly poorer on CBTT (p = 0.019) and BCST (p = 0.015, 0.047) compared with day workers. Significant differences were also observed between shift workers and day workers in terms of variables of omission errors (p = 0.037) and commission errors (p = 0.041) on CPT, but no significant difference was found between shift workers and day workers in reaction time (p = 0.561). Shift work impaired EF. These findings are related to shift workers' poorer sleep and its detrimental effects on areas of the brain, which are critical for EF, such as the prefrontal area. Our results suggest the evaluation and implication of practices and policies to assuage the consequences of working in shifts.

Association between maternal shift work and infant neurodevelopmental outcomes: results from the Taiwan Birth Cohort Study with propensity-score-matching analysis

BACKGROUND

Maternal shift work is associated with preterm delivery, small-for-gestational-age new-borns, childhood obesity and future behavioural problems. However, the adverse effects on and interactions of maternal shift work with infant neurodevelopment remain uncertain. Therefore, we examined the associations between maternal-shift-work status and infant neurodevelopmental parameters.

METHODS

The Taiwan Birth Cohort Study is a nationwide birth cohort study following representatively sampled mother-infant pairs in 2005. The participants' development and exposure conditions were assessed by home interviews with structured questionnaires at 6 and 18 months of age. Propensity scores were calculated with predefined covariates for 1:1 matching. Multivariate conditional logistic regression and the Cox proportional-hazards model were used to examine the association between maternal-shift-work status and infant neurodevelopmental-milestone-achievement status.

RESULTS

In this study, 5637 term singletons were included, with 2098 cases selected in the propensity-score-matched subpopulation. Persistent maternal shift work was associated with increased risks of delays in gross-motor neurodevelopmental milestones [aOR = 1.36, 95% confidence interval (CI) = 1.06-1.76 for walking steadily], fine-motor neurodevelopmental milestones (aOR = 1.39, 95% CI = 1.07-1.80 for scribbling) and social neurodevelopmental milestones (aOR = 1.35, 95% CI = 1.03-1.76 for coming when called upon). Moreover, delayed gross-motor and social development were identified in the propensity-score-matched sub-cohort.

CONCLUSIONS

This study shows negative associations between maternal shift work and delayed neurodevelopmental-milestone achievement in the gross-motor, fine-motor and social domains at 18 months. Future research is necessary to elucidate the possible underlying mechanisms and long-term health effects.

Sleep Improvement Effect on Sexual Life Quality Among Rotating Female Shift Workers: A Randomized Controlled Trial

BACKGROUND

Poor sleep quality consequences among shift working nurses are well recognized.

AIM

To investigate the impact of sleep improvement on sexual quality of life.

METHODS

The study was a parallel randomized controlled trial, conducted among 120 female nurses in 2 educational hospitals in the Northeast of Iran, Shahroud. Using random blocks of four, 120 eligible participants were randomly assigned to study groups. Data collecting tools included a demographic data questionnaire, Pittsburgh Sleep Quality Index to assess sleep quality, and the survey of sexual quality of life-female and Sexual Self-Efficacy Questionnaire to evaluate level of sexual quality of life and sexual self-efficacy, respectively. The intervention consisted of 3 weekly sleep intervention sessions that lasted from 90 to 120 minutes.

OUTCOMES

The study's primary and secondary outcomes were sleep quality, and the level of sexual self-efficacy and sexual quality of life, respectively.

RESULTS

By 3-month follow-up, the loss to follow-up rate was 5.9%. The mean sleep quality score was 7.61 ± 2.26 in the recruited participants. Following the intervention, the sleep quality score showed statistically significant differences compared to the control group [mean difference (CI 99.98%), -1.89 (-2.40, -1.38)]. Participants in the intervention group showed modest increases in both measures; sexual self-efficacy [mean difference (CI 99.98%), 8.82 (6.83, 10.81)] and sexual quality of life [mean difference (CI 99.98%), 19.64 (18.08, 21.20)].

CLINICAL IMPLICATIONS

These findings suggest that sleep improvement could promote the sexual quality of life among shift working nurses.

STRENGTHS & LIMITATIONS

Strengths of this study include the use of a validated outcome measure. Focusing the study on female nurses and the small size of the study population are the limitations.

CONCLUSION

Improved sleep showed an impact on sexual quality of life among rotating female shift workers. Khastar H, Mirrezaie SM, Chashmi NA, et al. Sleep Improvement Effect on Sexual Life Quality Among Rotating Female Shift Workers: A Randomized Controlled Trial. J Sex Med 2020;17:1467-1475.

Night work and risk of ischaemic heart disease and anti-hypertensive drug use: a cohort study of 145 861 Danish employees

Background

Ischaemic heart disease (IHD) and hypertension are leading causes of mortality and night work has been suspected as a risk factor. Meta-analyses and previous studies are often limited by power and various definitions of exposure and outcomes. This study aimed to investigate if night work increases the risk of IHD or anti-hypertensive drug usage in a large cohort of Danish employees.

Methods

Individual participant data on night work were drawn from the Danish Labour Force Survey (1999–2013). We included 145 861 participants (53% men) 21–59 years of age working 32 h or more per week. Participants with diagnosis or drug use in the year prior to baseline were excluded. Data on outcomes were obtained from nationwide health registers. Using Poisson regression we analyzed incidence rates of the outcomes as functions of night work adjusted for relevant covariates.

Results

We observed 3635 cases of IHD and 20 648 cases used anti-hypertensive drugs. When examining main effects the association of night work with drug use was estimated at rate ratio (RR): 1.05 (95% CI: 1.01–1.09). A sensitivity analysis suggested a dose-response association. The association of night work with IHD was estimated at RR: 1.08 (95% CI: 0.98–1.19). Overall likelihood ratio test showed no statistically significant associations between night work and IHD or drug use when including interactions with sex and socioeconomic status.

Conclusions

Night work was associated with an increased risk of anti-hypertensive drug use. Small estimates suggested a dose-response association. No statistically significant association between night work and IHD were found.

Sleep disturbance and cognitive functioning among firefighters

Firefighters are at risk for chronic sleep disruption due to their rotating 24-hour on and 48-hour off work schedule and hazardous work conditions. Forty-five firefighters were assessed to determine the impact of their shift schedule on sleep duration, sleep quality, processing speed, sustained attention, vigilance, and mental health. Assessments were conducted at the start and end of shift. Firefighters endorsed sleeping 5 hours 21 minutes at work, and the results suggest that even minimal sleep disruption affected cognitive functioning (e.g. processing speed, visual-motor coordination, and reaction time), increasing the likelihood of poor work performance or injury.

Wearable technologies for developing sleep and circadian biomarkers: a summary of workshop discussions

The "International Biomarkers Workshop on Wearables in Sleep and Circadian Science" was held at the 2018 SLEEP Meeting of the Associated Professional Sleep Societies. The workshop brought together experts in consumer sleep technologies and medical devices, sleep and circadian physiology, clinical translational research, and clinical practice. The goals of the workshop were: (1) characterize the term "wearable" for use in sleep and circadian science and identify relevant sleep and circadian metrics for wearables to measure; (2) assess the current use of wearables in sleep and circadian science; (3) identify current barriers for applying wearables to sleep and circadian science; and (4) identify goals and opportunities for wearables to advance sleep and circadian science. For the purposes of biomarker development in the sleep and circadian fields, the workshop included the terms "wearables," "nearables," and "ingestibles." Given the state of the current science and technology, the limited validation of wearable devices against gold standard measurements is the primary factor limiting large-scale use of wearable technologies for sleep and circadian research. As such, the workshop committee proposed a set of best practices for validation studies and guidelines regarding how to choose a wearable device for research and clinical use. To complement validation studies, the workshop committee recommends the development of a public data repository for wearable data. Finally, sleep and circadian scientists must actively engage in the development and use of wearable devices to maintain the rigor of scientific findings and public health messages based on wearable technology.

International Nursing: A Study of Sleep Quality Among Nurses and Its Correlation With Cognitive Factors

The objective of this study was to evaluate sleep quality and its relationship to cognitive factors among nurses. Sleep quality among nurses is an important issue, which requires more extensive study. Its correlation with cognitive ability has not been sufficiently considered. Five hundred forty nurses (66.3% female) working in 6 hospitals were selected as the sample of the study. Results show that nurses do not experience good quality of sleep. That is, 77.4% of the sample population of nurses have a poor quality of sleep, and nurses working the night shift have more sleep problems than other nurses. The results show that there is a relationship between dysfunctional beliefs and attitudes about sleep and metacognitive process and the quality of sleep, and that these variables can predict sleep quality. Based on the results of the study, it can be said that cognitive and metacognitive processes play an important role in sleep quality. Lack of sufficient sleep can create numerous problems for nurses and patients. Attention to the role of cognitive and metacognitive processes can help improve the sleep quality of nurses.

Rotating Nightshift Work and Hematopoietic Cancer Risk in US Female Nurses

Background

Nightshift work is a plausible risk factor for hematologic cancer, but epidemiological evidence remains sparse, especially for individual subtypes. We prospectively examined the association of rotating nightshift work with hematopoietic cancer risk.

Methods

This cohort study included US women from the Nurses’ Health Study (NHS: n = 76 846, 1988–2012) and Nurses’ Health Study II (NHSII: n = 113 087, 1989–2013). Rotating nightshift work duration was assessed at baseline (both cohorts) and cumulatively updated (NHSII). Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for overall hematopoietic cancer and specific histologic subtypes. All statistical tests were two-sided.

Results

We documented 1405 (NHS) and 505 (NHSII) incident hematopoietic cancer cases during follow-up. In NHS, compared with women who never worked rotating nightshifts, longer rotating nightshift work duration was associated with an increased risk of overall hematopoietic cancer (HR_1–14y = 0.93, 95% CI = 0.83 to 1.04; HR_≥15y = 1.28, 95% CI = 1.06 to 1.55; P_trend = .009). In NHSII, results were similar though not statistically significant (HR_1–14y = 0.99, 95% CI = 0.82 to 1.21; HR_≥15y = 1.41, 95% CI = 0.88 to 2.26; P_trend = .47). In the subtype analyses in the NHS, the association of history of rotating nightshift work with risk of diffuse large B-cell lymphoma varied by duration (HR_1–14y = 0.71, 95% CI = 0.51 to 0.98; HR_≥15y = 1.69, 95% CI = 1.07 to 2.67; P_trend = .01) compared with those who never worked rotating nightshifts. Women reporting a longer history of rotating nightshifts also had suggestive (statistically nonsignificant) increased risks of overall non-Hodgkin lymphoma (HR_≥15y = 1.19, 95% CI = 0.95 to 1.49), Hodgkin lymphoma (HR_≥15y = 1.32, 95% CI = 0.43 to 4.06), and multiple myeloma (HR_≥15y = 1.42, 95% CI = 0.85 to 2.39).

Conclusions

Longer duration (≥15 years) of rotating nightshift work was associated with increased risks of overall and several subtypes of hematopoietic cancer.

Evaluating the Effects of Different Sleep Supplement Modes in Attenuating Metabolic Consequences of Night Shift Work Using Rat Model

PURPOSE

To study the effects of chronic-simulated night shift work using the rat model and examines if a particular sleep supplement mode could be better in alleviating the effects.

METHODS

The male Wistar rats were randomly divided into the control (CTL: 8 rats) and night shift work (NW: 24 rats) groups of rats. Based on the sleep supplement strategy, the NW group was further segregated into three subgroups (8 rats each); late sleep supplement group (LSS), early sleep supplement group (ESS), and intermittent sleep supplement group (ISS). Sleep deprivation was achieved using the standard small-platform-over water method. Parameters such as animal body weight and food intake were measured daily. The intraperitoneal glucose tolerance test, fasting plasma insulin concentration, insulin resistance index and insulin sensitivity were measured twice, in the 4th and 8th weeks of the study. Plasma corticosterone concentration and pathological changes in islets (insulitis) were measured at the end of the 8th week.

RESULTS

In NW group, night work resulted in a gain of body weight and albeit lower than that of the CTL group. NW rats also had higher food intake, showed impaired glucose metabolism and higher plasma corticosterone concentration. The sleep supplement experiments suggested that compared to the other modes, intermittent sleep supplement had significantly low changes in the body weight, glucose metabolism and the islet cells.

CONCLUSION

Similar to previous studies, we also found that night shift work adversely impacts the body weight and glucose metabolism in rats. However, upon evaluating different sleep supplement strategies, we found the intermittent sleep supplement strategy to be most effective.

Improving fatigue risk management in healthcare: A systematic scoping review of sleep-related/fatigue-management interventions for nurses and midwives

BACKGROUND

Nurses and midwives make up almost 50% of the global healthcare shift working workforce. Shift work interferes with sleep and causes fatigue with adverse effects for nurses' and midwives' health, as well as on patient safety and care. Where other safety-critical sectors have developed Fatigue Risk Management Systems, healthcare is behind the curve; with published literature only focussing on the evaluation of discreet sleep-related/fatigue-management interventions. Little is known, however, about which interventions have been evaluated for nurses and midwives. Our review is a critical first step to building the evidence-base for healthcare organisations seeking to address this important operational issue.

OBJECTIVES

We address two questions: (1) what sleep-related/fatigue-management interventions have been assessed in nurses and midwives and what is their evidence-base? and (2) what measures are used by researchers to assess intervention effectiveness?

DESIGN AND DATA SOURCES

The following databases were searched in November, 2018 with no limit on publication dates: MEDLINE, PsychINFO and CINAHL.

REVIEW METHODS

We included: (1) studies conducted in adult samples of nurses and/or midwives that had evaluated a sleep-related/fatigue-management intervention; and (2) studies that reported intervention effects on fatigue, sleep, or performance at work, and on measures of attention or cognitive performance (as they relate to the impact of shift working on patient safety/care).

RESULTS

The search identified 798 potentially relevant articles, out of which 32 met our inclusion criteria. There were 8619 participants across the included studies and all were nurses (88.6% female). We did not find any studies conducted in midwives nor any studies conducted in the UK, with most studies conducted in the US, Italy and Taiwan. There was heterogeneity both in terms of the interventions evaluated and the measures used to assess effectiveness. Napping could be beneficial but there was wide variation regarding nap duration and timing, and we need to understand more about barriers to implementation. Longer shifts, shift patterns including nights, and inadequate recovery time between shifts (quick returns) were associated with poorer sleep, increased sleepiness and increased levels of fatigue. Light exposure and/or light attenuation interventions showed promise but the literature was dominated by small, potentially unrepresentative samples.

CONCLUSIONS

The literature related to sleep-related/fatigue-management interventions for nurses and midwives is fragmented and lacks cohesion. Further empirical work is warranted with a view to developing comprehensive Fatigue Risk Management Systems to protect against fatigue in nurses, midwives, and other shift working healthcare staff.

Improving Resident Well-Being During Shiftwork: Are Casino Shifts the Answer?

PURPOSE

The objective of this study is to quantitatively evaluate the well-being of residents doing casino shifts compared with those doing standard overnight shifts while working in an academic pediatric emergency department.

METHODS

A randomized prospective survey study was performed over a period of 1 year on all residents who were scheduled to complete a 28-day block. Each block (28-day period) within the year was designated as either a "standard" or "casino" block. The standard overnight shifts were scheduled from midnight to 0800 hours, and casino shifts occurred from either 2000 to 0400 hours (casino A) and 0400 to 1200 hours (casino B). Participating residents were asked to complete both a preblock and postblock survey. The primary outcome was defined as differences in resident well-being as assessed by the brief resident wellness profile (BRWP). A mood faces graphical rating item to assess overall mood was used as a secondary outcome measures as well as a 10-item survey based on World Health Organization domains for quality of life and adapted to reflect completion of shiftwork.

RESULTS

A total of 124 (90%) of 138 residents completed the study and were included in the analysis. No significant difference in resident well-being measured by BRWP between those in the standard and casino shift groups (17 ± 2.5 for preblock standard and 16.9 ± 2.8 for casino, P = 0.904; 17.1 ± 2.7 for postblock standard and 17.2 ± 3.1 for casino, P = 0.817), or in the relative change of the BRWP preblock and postblock between the 2 groups (standard, 0.35 ± 2.7; casino, 0.29 ± 3.0; P = 0.926). No significant difference in the mood faces rating scale scores or the 10-item postblock survey was found.

CONCLUSIONS

In the first study examining the effects of casino shifts on trainees, we found no effect of standard overnight versus casino shifts on their well-being. This counters the benefits previously seen in emergency department consultant staff and highlights the need for more studies specifically in trainees.

Exploring the Physical and Mental Health Challenges Associated with Emergency Service Call-Taking and Dispatching: A Review of the Literature

INTRODUCTION

Emergency service (ambulance, police, fire) call-takers and dispatchers are often exposed to duty-related trauma, placing them at increased risk for developing mental health challenges like stress, anxiety, depression, and posttraumatic stress disorder (PTSD). Their unique working environment also puts them at-risk for physical health issues like obesity, headache, backache, and insomnia. Along with the stress associated with being on the receiving end of difficult calls, call-takers and dispatchers also deal with the pressure and demand of following protocol despite dealing with the variability of complex and stressful situations.

METHODS

A systematic literature review was conducted using the MEDLINE, PubMed, CINAHL, and PsychInfo databases.

RESULTS

A total of 25 publications were retrieved by the search strategy. The majority of studies (n = 13; 52%) reported a quantitative methodology, while nine (36%) reported the use of a qualitative research methodology. One study reported a mixed-methods methodology, one reported an evaluability assessment with semi-structured interviews, one reported on a case study, and one was a systematic review with a narrative synthesis.

DISCUSSION

Challenges to physical health included: shift-work leading to lack of physical activity, poor nutrition, and obesity; outdated and ergonomically ill-fitted equipment, and physically confining and isolating work spaces leading to physical injuries; inadequate breaks leading to fatigue; and high noise levels and poor lighting being correlated with higher cortisol levels. Challenges to mental health included: being exposed to traumatic calls; working in high-pressure environments with little downtime in between stressful calls; inadequate debriefing after stressful calls; inappropriate training for mental-health-related calls; and being exposed to verbally aggressive callers. Lack of support from leadership was an additional source of stress.

CONCLUSION

Emergency service call-takers and dispatchers experience both physical and mental health challenges as a result of their work, which appears to be related to a range of both operational and support-based issues. Future research should explore the long-term effects of these physical and mental health challenges.

How Do Nurses Cope with Shift Work? A Qualitative Analysis of Open-Ended Responses from a Survey of Nurses

Nurses are frequently required to engage in shift work given the 24/7 nature of modern healthcare provision. Despite the health and wellbeing costs associated with shift work, little is known about the types of coping strategies employed by nurses. It may be important for nurses to adopt strategies to cope with shift work in order to prevent burnout, maintain wellbeing, and ensure high quality care to patients. This paper explores common strategies employed by nurses to cope with shift work. A workforce survey was completed by 449 shift working nurses that were recruited from a major metropolitan health service in Melbourne, Australia. Responses to open-ended questions about coping strategies were analysed using the framework approach to thematic analysis. Four interconnected main themes emerged from the data: (i) health practices, (ii) social and leisure, (iii) cognitive coping strategies, and (iv) work-related coping strategies. Although a range of coping strategies were identified, sleep difficulties often hindered the effective use of coping strategies, potentially exacerbating poor health outcomes. Findings suggest that in addition to improving nurses' abilities to employ effective coping strategies on an individual level, workplaces also play an important role in facilitating nurses' wellbeing.

The psychological and physiological health effects of fatigue

Background

The issue of employee fatigue is becoming increasingly prominent, particularly in safety-critical industries.

Aims

To produce an in-depth review collating the known psychological and physiological health and work effects of fatigue to guide mitigation strategies in safety-critical industries.

Methods

Literature searches were conducted via scientific databases using appropriate filters and keywords. The available results were collated into a review and commentary.

Results

Decreased sleep duration and chronodisruption have been shown to cause both significant morbidity and mortality. There is a large body of evidence showing strong associations between fatigue, reduced cognition and occupational accidents, as well as increased metabolic and reproductive health sequelae, some forms of cancer and mortality. Additional evidence links fatigue with mental, gastrointestinal, neurological and chronic pain sequelae.

Conclusions

Fatigue risk mitigation strategies should be implemented, not only to reduce these short- and long-term health risks in employees of safety-critical industries, but also to create more efficient, productive and effective workplace personnel with longer and more fulfilling careers. This requires improved acute fatigue mitigation, as well as the prevention of cumulative fatigue build-up and the formation of acute-on-chronic fatigue. The health recommendations for fatigue mitigation outlined in this paper are pertinent to all professions where employees have high rates of both acute and chronic fatigue.

Sleep, Sleep Disorders, and Sexual Dysfunction

Good sleep is necessary for good health. Sleep health is increasingly recognized as important for physical and mental health by both the medical profession and the general public, and there is great interest in how to avoid and treat sleep disorders and problems. Recent research indicates that insufficient sleep, disrupted sleep, and sleep disorders affect many aspects of human health including sexual function. In fact, patients with urological disorders or erectile dysfunction (ED) may have a sleep disorder that contributes to their urological or sexual dysfunction. Obstructive sleep apnea, insomnia, shift work disorder, and restless legs syndrome are all common sleep disorders and are associated with ED and/or other urological disorders. Therefore, careful attention should be paid to the diagnosis and treatment of concomitant sleep disorders in patients with sexual dysfunction. In this review, we provide an overview of what sleep is and how it is assessed in the clinic or laboratory; our current understanding of the functions of sleep and sleep health; a description of common sleep disorders, as well as how they are diagnosed and treated; and how sleep and its disorders are associated with male sexual dysfunction. Sleep is considered to be a 'third pillar of health', along with diet and exercise. With an understanding of common sleep disorders and how they can impact male sexual function, the urologist can ensure that sleep disorders are considered as a contributor to sexual dysfunction in their patients in order to provide them with the optimal treatment for overall health.

Cognitive Impairments during the Transition to Working at Night and on Subsequent Night Shifts

Demands of modern society force many work operations into the night when the internal circadian timekeeping system is promoting sleep. The combination of disturbed daytime sleep and circadian misalignment, which is common in overnight shift work, decreases cognitive performance, yet how performance may differ across multiple consecutive nights of shift work is not fully understood. Therefore, the primary aim of this study was to use a simulated night-shift protocol to examine the cognitive performance and ratings of sleepiness and clear-headedness across the hours of a typical daytime shift, a first night shift with an afternoon nap and extended wakefulness, and 2 subsequent overnight shifts. We tested the hypothesis that cognitive performance would be worse on the first night shift as compared with the baseline and subsequent nighttime shifts and that performance during nighttime shifts would be reduced as compared with the baseline daytime shift. Fifteen healthy adults (6 men) were studied in the 6-day in-laboratory protocol. Results showed that working during the night increased subjective sleepiness and decreased clear-headedness and performance on the Psychomotor Vigilance Task (i.e., slower median, fastest and slowest reaction times, and increased attentional lapses), Stroop color word task (decreased number of correct responses and slower median reaction time), and calculation addition performance task (decreased number attempted and correct). Furthermore, we observed limited evidence of sleepiness, clear-headedness, or performance adaptation across subsequent nights of simulated night work. Our findings demonstrate that night-shift work, regardless of whether it is the first night shift with a nap and extended wakefulness or subsequent night shifts, decreases performance and clear-headedness as compared with the day shift.

Decreased psychomotor vigilance of female shift workers after working night shifts

Background

We compared psychomotor vigilance in female shift workers of the Bergmannsheil University Hospital in Bochum, Germany (N = 74, 94% nurses) after day and night shifts.

Methods

Participants performed a 3-minute Psychomotor Vigilance Task (PVT) test bout at the end of two consecutive day and three consecutive night shifts, respectively. Psychomotor vigilance was analyzed with respect to mean reaction time, percentage of lapses and false starts, and throughput as an overall performance score, combining reaction time and error frequencies. We also determined the reaction time coefficient of variation (RTCV) to assess relative reaction time variability after day and night shifts. Further, we examined the influence of shift type (night vs. day) by mixed linear models with associated 95% confidence intervals (CI), adjusted for age, chronotype, study day, season, and the presence of obstructive sleep apnea (OSA).

Results

At the end of a night shift, reaction times were increased (β = 7.64; 95% CI 0.94; 14.35) and the number of lapses higher compared to day shifts (exp(β) = 1.55; 95% CI 1.16–2.08). By contrast, we did not observe differences in the number of false starts between day and night shifts. Throughput was reduced after night shifts (β = -15.52; 95% CI -27.49; -3.46). Reaction times improved across consecutive day and night shifts, whereas the frequency of lapses decreased after the third night. RTCV remained unaffected by both, night shifts and consecutive shift blocks.

Discussion

Our results add to the growing body of literature demonstrating that night-shift work is associated with decreased psychomotor vigilance. As the analysis of RTCV suggests, performance deficits may selectively be driven by few slow reactions at the lower end of the reaction time distribution function. Comparing intra-individual PVT-performances over three consecutive night and two consecutive day shifts, we observed performance improvements after the third night shift. Although a training effect cannot be ruled out, this finding may suggest better adaptation to the night schedule if avoiding fast-changing shift schedules.

Does My Emergency Department Doctor Sleep? The Trouble With Recovery From Night Shift

BACKGROUND

Previous research has shown that emergency physicians have an increased risk of shift work sleep disorder, potentially compromising their health, wellness, and effectiveness as a physician.

OBJECTIVES

This study explores the effect of shift work on sleep in emergency doctors. The hypothesis of the evaluation is that daytime sleep onset would lead to the poorest sleep, implying poor recovery after a night shift.

METHODS

Sleep patterns were examined in emergency physicians in an academic emergency department. Twenty-seven individuals completed data collection, wearing wrist actigraphy devices over 3 months. Time of sleep onset was categorized as falling into 1 of 3 ranges: interval 1-day sleepers (6:00 am-2:00 pm), interval 2-evening sleepers (2:00 pm-10:00 pm), or interval 3-night sleepers (10:00 pm-6:00 am). Data from each interval were analyzed for median duration, sleep latency, and night-time interruptions.

RESULTS

Daytime sleep sessions had a median total sleep duration of 5.3 ± 2 h, much less than 7.3 ± 1.8 h (interval 2-evening), and 7.0 ± 1.1 h (interval 3-night). Interval 2 sleepers experienced the highest number of nightly awakenings (1.5) and the longest sleep latency (36.5 min). Day sleepers (interval 1), assumed to be predominantly physicians recovering from night shifts, had significantly less sleep than both evening and night sleepers (p < 0.01), experiencing a 23.0% decrease in overall median sleep duration.

CONCLUSIONS

This study provides statistical findings that those working the night shift experience significantly less sleep than emergency physicians working other shifts.

Shift work of nursing professionals and blood pressure, burnout and common mental disorders

OBJECTIVE

To analyze the influence of shift work on blood pressure, the presence of burnout and common mental disorders in nursing professionals.

METHOD

A cross-sectional study. Burnout was assessed by the Maslach Burnout Inventory, and Common Mental Disorders by the Self-Reporting Questionnaire. Casual blood pressure measurement and Ambulatory Blood Pressure Monitoring (ABPM) were performed.

RESULTS

231 professionals participated. The majority (59.7%) worked in shifts, and this condition was associated (p≤0.05) with: higher weekly workload; doing the night shift; shorter training and work time at the institution; alcoholism; leisure activity; and alteration in ambulatory blood pressure monitoring of the sleep period. The professionals with common mental disorders and who worked in shifts had lower casual diastolic pressure levels (p = 0.039) and higher hypertension prevalence (p = 0.045). The presence of emotional exhaustion was associated with normal waking blood pressure and depersonalization with altered sleep blood pressure.

CONCLUSION

Shift work was associated with a higher prevalence of work-related negative factors, inadequate habits and lifestyles, and change in sleep blood pressure.

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.

A reductionist, in vitro model of environmental circadian disruption demonstrates SCN-independent and tissue-specific dysregulation of inflammatory responses

Environmental circadian disruption (ECD), characterized by repeated or long-term disruption in environmental timing cues which require the internal circadian clock to change its phase to resynchronize with the environment, is associated with numerous serious health issues in humans. While animal and isolated cell models exist to study the effects of destabilizing the relationship between the circadian system and the environment, neither approach provides an ideal solution. Here, we developed an in vitro model which incorporates both elements of a reductionist cellular model and disruption of the clock/environment relationship using temperature as an environmental cue, as occurs in vivo. Using this approach, we have demonstrated that some effects of in vivo ECD can be reproduced using only isolated peripheral oscillators. Specifically, we report exaggerated inflammatory responses to endotoxin following repeated environmental circadian disruption in explanted spleens. This effect requires a functional circadian clock but not the master brain clock, the suprachiasmatic nucleus (SCN). Further, we report that this is a result of cumulative, rather than acute, circadian disruption as has been previously observed in vivo. Finally, such effects appear to be tissue specific as it does not occur in lung, which is less sensitive to the temperature cycles employed to induce ECD. Taken together, the present study suggests that this model could be a valuable tool for dissecting the causes and effects of circadian disruption both in isolated components of physiological systems as well as the aggregated interactions of these systems that occur in vivo.

Associations between sleep disturbances, mental health outcomes and burnout in firefighters, and the mediating role of sleep during overnight work: A cross-sectional study

This study investigated whether sleep disorder risk and mental health outcomes in firefighters were associated with burnout, particularly emotional exhaustion, and examined the mediating role of sleep at work in these relationships. A secondary aim was to investigate associations between habitual sleep characteristics and burnout. North American firefighters (n = 6,307) completed the Maslach Burnout Inventory (emotional exhaustion, depersonalisation, personal accomplishment), and were screened for sleep disorders and self-reported current mental health conditions and sleep characteristics. Multiple logistic regression analyses examined associations between sleep, mental health outcomes and burnout. Firefighters screening positive for a sleep disorder, particularly insomnia, had increased risk of emotional exhaustion (adjusted odds ratio 3.78, 95% confidence interval 2.97-4.79). Firefighters self-reporting a current mental health condition were at greater risk of emotional exhaustion (adjusted odds ratio 3.45, 95% confidence interval 2.79-4.27). Sleep during overnight work mediated the impact of having a sleep disorder and mental health condition on high burnout. Sleepiness and sleep deficit (difference between required and actual sleep), even in firefighters without sleep disorder risk, were associated with depersonalisation (adjusted odds ratio 1.65, 95% confidence interval 1.34-2.03 and adjusted odds ratio 1.29, 95% confidence interval 1.06-1.57, respectively) and low personal accomplishment (adjusted odds ratio 1.25, 95% confidence interval 1.07-1.47 and adjusted odds ratio 1.17, 95% confidence interval 1.01-1.35, respectively). Sleep and mental health problems were associated with increased risk of burnout in firefighters, and sleep during overnight work mediated these relationships. The results suggest the need to examine the effectiveness of occupational interventions that improve the opportunity for sleep, together with screening for and treating sleep disorders, to reduce burnout risk.

Occupational fatigue and mental health complaints among 8-hour shift workers of petrochemical industries in Iran

BACKGROUND

Shift working is unavoidable in many industries with continual material processing such as petrochemical plants. So, the adverse effects of shift working on workers should be seriously considered.

OBJECTIVE

This cross-sectional study evaluated occupational fatigue and mental health complaints and their relationship in rotating 8-hour shift workers.

METHOD

In this study, 287 shift workers participated. The Multidimensional Fatigue Inventory (MFI-20) and General Health Questionnaire (GHQ-28) were used to evaluate the level of fatigue and mental health, respectively.

RESULT

A relatively high prevalence of mental health complaints (particularly social dysfunction) and fatigue (especially general fatigue) were found among the study population. In general, 43.4% of participants reported a mental health problem. A moderate correlation was found between fatigue and mental health (r = 0.58). The stepwise regression model revealed that fatigue was significantly related only to "anxiety and insomnia" and "severe depression".

CONCLUSION

This study revealed that the 8 h shift workers in studied areas are exposed to a considerable risk of mental health and fatigue. So, improving the ergonomics and health aspects of the workplace is recommended to reduce related risk factors.

Rotating Shifts Negatively Impacts Health and Wellness Among Intensive Care Nurses

The impact of shift work on sleep and health has been examined in the past, but most studies utilized cross-sectional designs relying on between-subject differences. The purpose this study was to examine the within-subject differences in self-report measures of health and wellness among a group of nurses engaged in rotating shifts. Patient-Reported Outcomes Measurement Information System (PROMIS) measures, collected post-day and post-night shift, were used to assess health, sleep disturbances and sleep-related impairment, fatigue, emotional distress (anger), satisfaction with social roles outside of work, and applied cognitive abilities. Among the sample of 23 White, mostly female (91.3%) nurses, all PROMIS measures were worse indicting lower health and wellness after working night shifts compare to after working day shifts ( p values from .167 to < .001). During both time points of assessment, sleep-related impairment was highly correlated with greater emotional distress, greater fatigue, and worse memory and concentration. Study findings support prior studies that shift work can negatively impact health and wellness.