Predictors of shift work disorder among nurses: a longitudinal study

BackgroundShift work is associated with sleep problems and impaired health. The main aim of the present study was to explore predictors of developing shift work disorder (SWD) among Norwegian nurses using a longitudinal design.MethodsA total of 1533 nurses participating in a survey on shift work, sleep and health responded to questionnaires at baseline and at follow-up about two years later. SWD was defined as problems of excessive sleepiness and/or complaints of insomnia related to the work schedule.Results and ConclusionsThere was a significant reduction (p < 0.001) in the prevalence of SWD from baseline to follow-up, from 35.7% to 28.6%. Logistic regression analyses showed significant risks of having SWD at follow-up and the following variables measured at baseline: number of nights worked the last year (OR = 1.01, 95% CI = 1.01–1.02), having SWD (OR = 5.19, 95% CI = 3.74–7.20), composite score on the Epworth Sleepiness Scale (OR = 1.08, 95% CI = 1.04–1.13), use of melatonin (OR = 4.20, 95% CI = 1.33–13.33), use of bright light therapy (OR = 3.10, 95% CI 1.14–8.39), and symptoms of depression measured by the Hospital Anxiety and Depression Scale (OR = 1.07, 95% CI = 1.00–1.14). In addition, leaving night work between baseline and follow-up was associated with a significantly reduced risk of SWD at follow-up (OR = 0.12, 95% CI = 0.07–0.22).     

The impact of the shift system on health and quality of life of sleep technicians

BackgroundSleep technicians are at high risk of shift work sleep disorders. We therefore aimed to identify the optimal shift system for sleep technicians.MethodsWe performed a nationwide survey of the work schedules, health and quality of life of sleep technicians using e-mail questionnaires including the Insomnia Severity Index (ISI), Epworth Sleep Scale (ESS), Functional Outcomes of Sleep Questionnaire-10 (FOSQ-10), Short Form-12 Health Survey (SF-12), and Hospital Anxiety and Depression Scale (HADS) in Korea. A multivariate general linear model was used to assess the effect of shift schedules on health and quality of life.ResultsFifty-four technicians from 30 sleep laboratories participated. Their work schedules were classified as fixed night (F) (n = 18), slow rotation alternating from a night-only to a day-only schedule with a 3-months to one-year interval (S) (n = 20), rapid rotation within a week (R) (n = 5), night once a week (D+) (n = 5) and day (D) (n = 6). The adjusted ISI and HADS-anxiety scores were higher in F, S, and R than D and D+. Among night shift-dominant schedules, a less favorable profile was observed for R followed by F, and S regarding the ISI, FOSQ-10, mental SF-12 and HADS-depression. The physical SF-12 was lower in the order of R, S and F. The HADS-anxiety score was higher in the order of F, R and S.ConclusionsThe S system appears to have the least negative effect on health and quality of life among night shift-dominant systems. The development of consensus guidelines for scheduling shifts in sleep laboratories is urged.     

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

BackgroundShift 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.MethodsA 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.ResultsIn 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.ConclusionsThese 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.     

Regional gray matter changes in shift workers: a voxel-based morphometry study

ObjectivePrevious neuroimaging studies have shown subtle structural changes of the brain in various sleep disorders, suggesting detrimental effects of disrupted sleep–wake cycle on brain structures. We aimed to identify structural changes in shift workers relative to day workers. We hypothesized that brain structures belonging to sleep–wake modulation may be altered in shift workers.MethodsNineteen male shift workers (median age, 21 years) and 19 male day workers (median age, 21 years) voluntarily participated in the current study. Sleep questionnaires were obtained from all participants and compared between the groups. Voxel-based morphometry was used to compare regional gray matter volume between shift workers and day workers (corrected p < 0.05 with small volume correction). Separate correlation analyses were performed between regional gray matter volume change and scores of Epworth Sleepiness Scale and Pittsburgh Sleep Quality Index (Pearson's correlation, p < 0.05).ResultsCompared to day workers, shift workers had higher scores of Beck Depression Inventory-II, Epworth Sleepiness Scale, and Pittsburgh Sleep Quality Index. Compared to day workers, shift workers had a significant gray matter volume reduction in the pontomesencephalic tegmentum. Regional volume of the pontomesencephalic tegmentum negatively correlated with Pittsburgh Sleep Quality Index global score.ConclusionsWe observed that pontomesencephalic tegmentum volume was reduced in shift workers compared to day workers and that the smaller pontomesencephalic tegmentum volume was related to the poorer sleep quality. Our preliminary findings may be related to chronic disruption of circadian rhythm or decreased exposure to bright light in shift workers.     

Sleep parameters assessed by actigraphy in Fabry's disease patients: a proof-of-concept

BackgroundIn a previous study developed by our group, we identified a phase inversion in 6-sulfatoxymelatonin – melatonin metabolite in urine – daily profile in Fabry's disease patients. Since melatonin is an endogenous marker, it could also be accompanied by behavioral changes in sleep-wake cycle, which impairs the overall patient's life quality.ObjectiveIn this study, we evaluated sleep-wake cycle in Fabry disease patients. We hypothesized that patients would have increased daytime naps, given our previous results for urinary 6-sulfatoxymelatonin.Patients/methodsThis was a cross-sectional and case–control study, performed between October 2016 and May 2017. Volunteers recorded activity and rest rhythm by actigraphy and answered Pittsburgh Sleep Quality Index (PSQI). From actigraphy data, we calculated sleep parameters: sleep latency, wake after sleep onset, sleep (WASO) efficiency, awakenings index (PSQI), and the amount and duration of daytime naps. We included 16 Fabry disease patients with biochemical and molecular diagnosis and 10 control individuals matched by age and gender.ResultsWe did not observe significant differences for any of the parameters analyzed (p > 0.05). However, evaluating the magnitude of the effect, we found that patients dozed, on average, about 42 min longer (d = 0.9 - large effect size) than control group.ConclusionsThis is a preliminary study, a proof-of-concept, and our results indicate that changes in melatonin secretion phase may have behavioral consequences in sleep-wake cycle, with longer duration of daytime naps.     

Sleep and circadian alterations in people at risk for bipolar disorder: A systematic review

BackgroundSleep and circadian abnormalities have been mostly demonstrated in bipolar patients. However, it is not clear whether these alterations are present in population at high risk for bipolar disorder (BD), indicating a possible risk factor for this condition.ObjectiveThis systematic review aims to define current evidence about sleep and rhythm alterations in people at risk for BD and to evaluate sleep and circadian disorders as risk factor for BD.MethodsThe systematic review included all articles about the topic until February 2016. Two researchers performed an electronic search of PubMed and Cochrane Library. Keywords used were ‘sleep’ or ‘rhythm’ or ‘circadian’ AND ‘bipolar disorder’ or ‘mania’ or ‘bipolar depression’ AND ‘high-risk’ or ‘risk’.ResultsThirty articles were analyzed (7451 participants at risk for BD). Sleep disturbances are frequent in studies using both subjective measures and actigraphy. High-risk individuals reported irregularity of sleep/wake times, poor sleep and circadian rhythm disruption. Poor sleep quality, nighttime awakenings, and inadequate sleep are possible predictive factors for BD. A unique study suggested that irregular rhythms increase risk of conversion. People at risk for BD showed high cortisol levels in different times of day. Studies about anatomopathology, melatonin levels, inflammatory cytokines and oxidative stress were not identified. The most important limitations were differences in sleep and rhythm measures, heterogeneity of study designs, and lack of consistency in the definition of population at risk.ConclusionSleep and circadian disturbances are common in people at risk for BD. However, the pathophysiology of these alterations and the impact on BD onset are still unclear.     

Predictors of long-term work disability in Major Depressive Disorder: a prospective study

OBJECTIVE: Major Depressive Disorder (MDD) is a major cause of long-term work disability. However, factors predicting this are not well known. METHOD: In the Vantaa Depression Study, predictors for being granted a disability pension during an 18-month follow-up were examined among the 186 psychiatric MDD in- and out-patients belonging to the labour force at baseline. RESULTS: The 21 patients (11.3%) granted a disability pension were significantly older, more hopeless, had worse social and occupational functioning, and spent more time depressed during follow-up. After adjusting for these predictors, being on sick leave at baseline still strongly predicted disability pension during follow-up. CONCLUSION: Disability pension is predicted by multiple sociodemographic and clinical factors. Baseline level of functioning and duration of depressive episodes are key clinical predictors. The positive and negative consequences of sick leave warrant closer attention.     

The cortisol awakening response: a pilot study on the effects of shift work, morningness and sleep duration

This study concerned the possible influence of experimental shift work, morningness and sleep length on the cortisol awakening response (CAR). Eight morning-oriented (MT) and eight evening-oriented (ET) healthy young men (19-27 years) slept after three consecutive day shifts during the night and after three consecutive night shifts during the day in the laboratory. Salivary cortisol concentrations were ascertained after each sleep period upon awakening and half an hour later, half-hourly during work shifts, and hourly during two 24-h periods, after the three day shift/night sleep sequences and after the three night shift/day sleep sequences. Statistical analyses considered the temporal position of sleep (night, day), the succession of sleep periods, the diurnal type and the polysomnographically verified total sleep time. The CAR was significantly smaller after day than after night sleep and increased significantly with total sleep time in ET. MT had moderately higher cortisol concentrations upon awakening than ET probably because they wake up at a later time of their circadian rhythm. But neither the CARs nor the cortisol concentrations during the following work shifts or during the 24h profiles were different in both diurnal types. The cortisol concentrations during work shifts correlated significantly with the previous post-awakening concentrations in MT but not in ET. Due to the small samples further studies are needed.     

Sleep disturbances,work stress and work hours: a cross-sectional study

OBJECTIVE: The study examined the multivariate relationship between disturbed sleep and different work-related and background/life style factors. METHODS: 5720 healthy employed men and women living in the greater Stockholm area participated. A factor analysis of eight items provided one main factor: "disturbed sleep." The data were analyzed using a multiple logistic regression analysis against the index disturbed sleep as well as the separate items "not well rested" and "difficulties awakening." RESULTS: The results showed that high work demands [odds ratio (OR) = 2.15] and physical effort at work (OR = 1.94) are risk indicators for disturbed sleep, while high social support is associated with reduced risk (OR = 0.44). In addition, higher age (45+), female gender, a high body mass index (BMI) and lack of exercise are background/life style risk indicators. Introducing into the model an item representing inability to stop thinking about work during free time yielded the highest OR (3.20) and forced work demands out of the regression. With regard to not feeling well rested, the same significant predictors, except physical effort, were obtained, as well as for having night work and being married. In addition, the age effect was reversed--high age predicted reduced risk of not feeling well rested. Difficulties awakening was predicted by high work demands, low social support, being male, low age and smoking. It is notable that, whereas subjective sleep quality decreased with age, the difficulties awakening and feelings of not being well rested after sleep increased with age. CONCLUSION: It was concluded that stress and the social situation at work are strongly linked to disturbed sleep and impaired awakening, that gender and, even more so, age may modify this and that the inability to stop worrying about work during free time may be an important link in the relation between stress and sleep.     

Obstructive sleep apnea,shift work and cardiometabolic risk

Obstructive Sleep Apnea (OSA) is one of the most common sleep disorders, and invokes numerous negative health-related outcomes and physiopathological processes. Understanding the mechanisms by which OSA potentiates cardiometabolic risk of patients remains a current challenge. Sleep disruption is highly prevalent among shift workers and shift work (SW) is an important modulator of circadian rhythms, with health consequences intimately related to cardiometabolic health. Since the circadian timing system (CTS) interacts with the normal functioning of the ANS, CTS impact on OSA patients should be closely assessed. This review raises the question of whether SW-induced circadian misalignment potentiates the cardiometabolic risk of OSA patients, providing a novel perspective on the role of autonomic modulation as a key downstream mechanism linking cardiometabolic risk with both OSA and CTS misalignment.     

Altered sleep rhythm: A patient with a 10 to 15 day cycle

Summary A severely brain-damaged boy of 12 years had a prolonged sleep-wakefulness cycle of 10–15 days' duration. His body temperature followed a circadian rhythm, suggesting that some normal circadian oscillators were intact. The long sleep-wakefulness cycle could not be influenced by either methylphenidate administration or enforced wakefulness, which suggests that the cycle did not have the same properties as other rhythms, and the 10–15-day periods of sleep-wakefulness were probably controlled by mechanisms different from those operating in normal state. The case shows that there are multiple oscillating mechanisms in the control of different rhythms in humans.

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Zusammenfassung Ein zwölf Jahre alter Junge, der seit seinem achten Monat an Enzephalopathie litt, zeigte einen verlängerten Schlaf-Wach-Zyklus mit einer Dauer von 10–15 Tagen. Seine Körpertemperatur folgte dabei einem circadianen Rhythmus, aus dem geschlossen werden kann, daß einige normale circadianen Oszillatoren intakt waren.Dieser lange Schlaf-Wach-Zyklus konnte weder durch Gaben von Methylphenydat noch durch heftiges Wecken gestört werden, woraus man schließen kann, daß der Zyklus nicht dieselben Eigenschaften besitzt wie andere Rhythmen und die 10–15-tägige Periode des Schlafens und Wachens wahrscheinlich durch Mechanismen kontrolliert werden, die sich sehr von denen unterscheiden, welche das Verhalten im Normalzustand steuern.Das Datenmaterial belegt das Vorhandensein multipler Schwingungsrhythmen beim Menschen.

     

Feasibility of electronic sleep disorder screening in healthcare workers of a large healthcare system

Study objectivesMany healthcare workers live with sleep disorders and may be unaware of their condition. We aimed to ascertain sleep disorder symptoms including high-risk obstructive sleep apnea (hrOSA), significant insomnia, and excessive daytime sleepiness (EDS) by work shift in a sample of healthcare workers. We aim to inform the development of a mobile application for sleep disorder screening and electronically-delivered follow-up recommendations.MethodsAn initial survey, including the Epworth Sleepiness Scale (ESS) for EDS, Insomnia Severity Scale (ISI) for insomnia, and STOP questionnaire for hrOSA, was completed by healthcare workers at the Cleveland Clinic. A follow-up survey sent ∼3–6 months after screening assessed perceptions of the utility of screening and subsequent actions taken by those with abnormal scores.Results871 of 2851 (30.7%) workers who participated had abnormal ESS scores, with a significantly greater portion of night shift workers with abnormal scores compared to day or evening shift workers (p < 0.001). 27.5% of all workers had moderate to severe insomnia symptoms, with higher percentages of moderate or severe scores in evening and night shift workers (p < 0.001). 36.9% of workers had hrOSA, and of those previously diagnosed with obstructive sleep apnea (OSA) and using positive airway pressure therapy, over 90% reported treatment adherence (≥4 h per night). At follow-up, 92% of 484 respondents believed that sleep screening was valuable, with most taking some action after receiving abnormal results and over a quarter seeking sleep center treatment.ConclusionsMany healthcare workers, especially shift workers, experience sleep disorder symptoms, and our findings suggest that electronic sleep disorder symptom screening is feasible.     

Sleep quality and sleep disturbances among volunteer and professional French firefighters: FIRESLEEP study

BackgroundAlthough insufficient sleep among firefighters reduces work efficiency and increases the risk of injury, little is known about the sleep quality of French firefighters in the Loire department. The aim of the FIRESLEEP study was to evaluate sleep quality and sleep disturbances among professional and voluntary French firefighters.MethodsA cross-sectional observational study was conducted between November 2018 and May 2019. Firefighters were invited to complete a questionnaire on a secure platform including clinical questions and validated questionnaires (Pittsburgh Sleep Quality Index [PSQI], Epworth sleepiness scale [ESS], Insomnia Severity Index [ISI] and the STOP-Bang score) during their periodic medical examination.Results193 firefighters were included in this study, of which 29% were of professional status and 71% were volunteer firefighters. Among them, 26.9% had poor sleep quality, 27.7% showed excessive daytime sleepiness (EDS), 18.8% reported moderate-to-severe symptoms of insomnia, and 1.6% had moderate-to-high risk of obstructive sleep apnea. Subgroup analysis revealed that professional firefighters had poorer sleep quality and higher sleep disturbances than volunteer firefighters. The independent risk factors associated with poor sleep quality were known sleep disorder, treated anxiety/depression, night calls, and insomnia symptoms. Moreover, the independent risk factors associated with EDS were short sleep duration, taking a nap, and insomnia symptoms; while older age was a protective factor for EDS.ConclusionsPoor sleep quality and sleep disturbances are highly frequent in French firefighters and underdiagnosed. Prevention through education and systematic screening could limit the impact of sleep disturbances on firefighters' global health.     

Associations of shift work and night work with risk of all-cause,cardiovascular and cancer mortality: a meta-analysis of cohort studies

BackgroundEpidemiological studies on the relationship of shift work or night work with risk of total and cause-specific mortality have given conflicting results. We aimed at conducting a meta-analysis to summarize the evidence from cohort studies.MethodsEmbase, PubMed, Web of Science and Scopus databases were searched for eligible studies up to Mar 2021. Cohort studies evaluating the associations of shift work or night work with risk of all-cause, cardiovascular or cancer mortality were reviewed. Study-specific risk estimates were pooled by fixed-effect models when the heterogeneity was not detected; otherwise, random-effect models were employed.ResultsWe identified seventeen eligible articles (sixteen cohorts). A total of 958,674 cohort participants were included, with 38,413 total deaths, 24,713 cardiovascular deaths and 10,219 cancer deaths during follow-up. According to the Newcastle–Ottawa Scale, fifteen studies were considered as relatively high quality with low risk of bias. Compared with regular daytime workers, the pooled relative risks for all-cause, cardiovascular and cancer mortality were 1.02 (95% CI: 0.99, 1.06), 1.18 (95% CI: 0.94, 1.47) and 1.05 (95% CI: 0.83, 1.34) for those ever exposing to shift work, respectively. Compared with daytime workers or those never exposing to night work, the pooled relative risks for all-cause, cardiovascular and cancer mortality were 1.06 (95% CI: 1.03, 1.08), 1.15 (95% CI: 1.03, 1.29) and 1.04 (95% CI: 1.00, 1.08) for those ever exposing to night work, respectively. Moderate to high level of heterogeneity across the studies was detected. Publication bias was not detected.ConclusionNight work may be associated with higher risk of all-cause, cardiovascular and cancer mortality, suggesting that night workers compared with daytime workers may be at higher risk of death, especially due to cardiovascular disease.     

A 5-year prospective study of predictors for disability pension among patients with major depressive disorder

Holma IAK, Holma KM, Melartin TK, Rytsälä HJ, Isometsä ET. A 5‐year prospective study of predictors for disability pension among patients with major depressive disorder. Objective: There is a scarcity of prospective long‐term studies on work disability caused by depression. We investigated predictors for disability pension among psychiatric patients with MDD. Method: The Vantaa Depression Study followed up prospectively 269 psychiatric in‐ and out‐patients with DSM‐IV MDD for 5 years with a life chart, including 230 (91.3%) patients belonging to labour force. Information on disability pensions was obtained from interviews, patient records and registers. Results: Within 5 years, 20% of the patients belonging to labour force at baseline were granted a disability pension. In multivariate analyses, the significant baseline predictors for granted disability pension were age ≥50 years (HR = 3.91, P < 0.001), subjective inability to work (HR = 2.14, P = 0.008) and introversion (HR = 1.08, P = 0.049). When follow‐up variables were included, the predictors were age more than 50 (OR = 6.25, P < 0.001), proportion of time spent depressed (OR = 14.6, P < 0.001), number of comorbid somatic disorders (OR = 1.47, P = 0.013) and lack of vocational education (OR = 2.38, P = 0.032). Conclusion: Of psychiatric patients with depression, one‐fifth were granted a disability pension within 5 years. Future disability pension can be predicted by baseline older age, personality factors, functional disability, lack of vocational education and comorbid somatic disorders. Longitudinally, accumulation of time spent depressed appears decisive for pensioning.     

曲唑酮治疗抑郁症患者睡眠障碍的交叉试验研究

目的：验证曲唑酮对抑郁症患者的睡眠改善作用。方法：以艾司唑仑为对照药，采用交叉试验。结果；随着治疗的进行，曲唑酮与艾司唑一样，明显改善了抑郁症患者的睡眠指标，且两药对大多数观察指标的影响无明显差异。结论：曲唑酮能较好地改善抑郁症患者的睡眠障碍，具有较好的应用前景。