The Association Between Shift Work And Affective Disorders: A Systematic Review

Monitoring Daily Sleep, Mood, and Affect Using Digital Technologies and Wearables: A Systematic Review

Background: Sleep and affective states are closely intertwined. Nevertheless, previous methods to evaluate sleep-affect associations have been limited by poor ecological validity, with a few studies examining temporal or dynamic interactions in naturalistic settings. Objectives: First, to update and integrate evidence from studies investigating the reciprocal relationship between daily sleep and affective phenomena (mood, affect, and emotions) through ambulatory and prospective monitoring. Second, to evaluate differential patterns based on age, affective disorder diagnosis (bipolar, depression, and anxiety), and shift work patterns on day-to-day sleep-emotion dyads. Third, to summarise the use of wearables, actigraphy, and digital tools in assessing longitudinal sleep-affect associations. Method: A comprehensive PRISMA-compliant systematic review was conducted through the EMBASE, Ovid MEDLINE(R), PsycINFO, and Scopus databases. Results: Of the 3024 records screened, 121 studies were included. Bidirectionality of sleep-affect associations was found (in general) across affective disorders (bipolar, depression, and anxiety), shift workers, and healthy participants representing a range of age groups. However, findings were influenced by the sleep indices and affective dimensions operationalised, sampling resolution, time of day effects, and diagnostic status. Conclusions: Sleep disturbances, especially poorer sleep quality and truncated sleep duration, were consistently found to influence positive and negative affective experiences. Sleep was more often a stronger predictor of subsequent daytime affect than vice versa. The strength and magnitude of sleep-affect associations were more robust for subjective (self-reported) sleep parameters compared to objective (actigraphic) sleep parameters.

Circadian misalignment impairs oligodendrocyte myelination via Bmal1 overexpression leading to anxiety and depression-like behaviors

Circadian misalignment (CM) caused by shift work can increase the risk of mood impairment. However, the pathological mechanisms underlying these deficits remain unclear. In the present study, we used long-term variable photoperiod (L-VP) in wild-type mice to better simulate real-life shift patterns and study its effects on the prefrontal cortex (PFC) and hippocampus, which are closely related to mood function. The results showed that exposure to L-VP altered the activity/rest rhythms of mice, by eliciting phase delay and decreased amplitude of the rhythms. Mice with CM developed anxiety and depression-like manifestations and the number of mature oligodendrocytes (OL) was reduced in the medial prefrontal cortex and hippocampal CA1 regions. Mood impairment and OL reduction worsened with increased exposure time to L-VP, while normal photoperiod restoration had no effect. Mechanistically, we identified upregulation of Bmal1 in the PFC and hippocampal regions of CM mice at night, when genes related to mature OL and myelination should be highly expressed. CM mice exhibited significant inhibition of the protein kinase B (AKT)/mTOR signaling pathway, which is directly associated to OL differentiation and maturation. Furthermore, we demonstrated in the OL precursor cell line Oli-Neu that overexpression of Bmal1 inhibits AKT/mTOR pathway and reduces the expression of genes OL differentiation. In conclusion, BMAL1 might play a critical role in CM, providing strong research evidence for BMAL1 as a potential target for CM therapy.

The unfixed light pattern contributes to depressive-like behaviors in male mice

Light pollution is now associated with an increased incidence of mental disorders in humans, and the unfixed light pattern (ULP) is a common light pollution that occurs in such as rotating shift work. However, how much contribution the ULP has to depression and its potential mechanism are yet unknown. Our study aimed to investigate the effect of the ULP on depressive-like behaviors in mice and to explore the links to the circadian-orexinergic system. Male C57BL/6 J mice were exposed to the ULP by subjecting them to an alternating light pattern every 6 days for 54 days. The tail suspension test (TST) and forced swimming test (FST) were conducted to assess depressive-like behaviors. The rhythm of locomotor activity and the circadian expression of cFOS in the suprachiasmatic nucleus (SCN), clock genes in the liver, and corticosterone (CORT) in serum were detected to observe changes in the circadian system. The circadian expression of orexin-A (OX-A) in the lateral hypothalamus area (LHA) and dorsal raphe nucleus (DRN) and serotonin (5-HT) in the DRN were measured to determine alterations in the orexinergic system. The results showed that mice exposed to the ULP exhibited increased immobility time in the TST and FST. The ULP significantly disrupted the circadian rhythm of locomotor activity, clock genes in the liver, and CORT in the serum. Importantly, when exposed to the ULP, cFOS expression in the SCN showed decreased amplitude. Its projection area, the LHA, had a lower mesor of OX-A expression. OX-A projection to the DRN and 5-HT expression in the DRN were reduced in mesor. Our research suggests that the ULP contributes to depressive-like behaviors in mice, which might be related to the reduced amplitude of circadian oscillation in the SCN and hypoactivity of the orexinergic system. These findings may provide novel insights into rotating shift work-related depression.

Sleep disturbances and depressive symptoms of shift workers: Effects of shift schedules

This study explored sleep disturbances and depression among various types of shift workers (SWs) and non-SWs, focusing on work schedule diversity. We enrolled 6,654 adults (4,561 SWs, 2,093 non-SWs). Based on self-report questionnaires on work schedules, the participants were classified according to shift work type: non-shift work; and fixed evening, fixed night, regularly rotating, irregularly rotating, casual, and flexible shift work. All completed the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Insomnia Severity Index (ISI), and short-term Center for Epidemiologic Studies-Depression scale (CES-D). SWs reported higher PSQI, ESS, ISI, and CES-D than non-SWs. Fixed SWs (fixed evenings and fixed nights) and true SWs (regularly and irregularly rotating SWs) scored higher on the PSQI, ISI, and CES-D than non-SWs. True SWs scored higher on the ESS than fixed SWs and non-SWs. Among fixed SWs, fixed night SWs scored higher on the PSQI and ISI than fixed evening SWs. Among true SWs, irregular SWs (irregularly rotating and casual SWs) scored higher on the PSQI, ISI, and CES-D compared to regularly rotating SWs. The PSQI, ESS, and ISI independently were associated with the CES-D of all SWs. We found an interaction between the ESS and the work schedule on the one hand, and the CES-D on the other, which was stronger in SWs than non-SWs. Fixed night and irregular shifts were linked with sleep disturbances. The depressive symptoms of SWs are associated with sleep problems. The effects of sleepiness on depression were more prominent in SWs than non-SWs.

Impact of atypical working hours on sleep and mood among healthcare workers

BACKGROUND

Atypical working hours have raised serious concerns about health effects, such as sleep disorders and psychological repercussions. These schedules are frequent among health professionals having the obligation to ensure the permanence of health services.

OBJECTIVE

To assess the impact of atypical working hours on sleep, sleepiness, and mood among health personnel (HP).

METHODS

Comparative descriptive cross-sectional study was carried out among HP of a regional hospital in Southern Tunisia from December 2019 to May 2020. Two groups were defined according to their work schedule: group A had a fixed-day work and group B had atypical working hours. The assessment of sleep, sleepiness, and mood was based respectively on the Spiegel questionnaire, the Epworth Sleepiness Scale, and the Hospital Anxiety and Disorder scale.

RESULTS

A total of 101 HP in group A and 135 in group B were included. We found signs of pathological sleep in group B: greater delay in falling asleep (78.1% Vs 53.5%; p = 0.002), altered sleep quality (88.1% Vs 56.4%; p = 0.039), and more frequent occurrence of dreams (37% Vs 31.7%; p = 0.033). The quality of sleep was associated with the professional seniority (p = 0.01), the workplace (p = 0.02), and having dependent children (p = 0.04). The mean score of depression was higher in group B (p = 0.02). Depression was associated with the workplace (p = 0.04) and the quality of sleep (p = 0.01).

CONCLUSION

The results of this study indicate that atypical working hours generate both sleep and mood disorders in HP. It is vital to encourage the occupational physicians to estimate sleep and mood disorders in HP.

Network structure of insomnia and depressive symptoms among shift workers in China

A bidirectional relationship between insomnia and depression has been observed. However, few studies have used network analysis to explore the interaction patterns in that association at the symptom level. This study aimed to estimate network structures of insomnia and depressive symptoms among shift workers, as well as to compare the differences in network properties between individuals without and with insomnia symptoms and/or at risk of depression. A total of 1883 shift workers were included in our study. Insomnia symptoms were evaluated by three items based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders, and depressive symptoms were assessed by the Center for Epidemiologic Studies Depression Scale. Network analyses were used for the statistical analysis. "Difficulty initiating sleep", "Hard to get started", and "Depressed mood" with higher expected influence (EI) values were identified as the most central symptoms within the insomnia-depressive networks among shift workers. The significant differences between individuals without and with insomnia symptoms and/or at risk of depression were observed in symptoms of "Difficulty initiating sleep" and "Hard to get started". "Depressed mood", "Difficulty initiating sleep", or "Hard to get started" were the most key symptoms that trigger and sustain the structure of insomnia and depressive symptom among shift workers. Hence, timely intervention for the above three symptoms in future research or clinical practice (e.g., cognitive behavioral therapy for insomnia) may be crucial in alleviating insomnia and depressive symptoms among shift workers.

The Effect of Employee-Oriented Flexible Work on Mental Health: A Systematic Review

The effect of flexible work on mental health is not well known. The aim of this systematic review was to assess the effects of employee-oriented flexible work on mental health problems and associated disability. Literature searches were conducted in the PubMed, Scopus, Web of Sciences, Cochrane Library, PsycINFO, ProQuest and EconPapers databases from their inception through October-November 2020. Sixteen studies on the associations of worktime control, working from home, or flexible working arrangements with mental health related outcomes were included in the review: one cluster randomized controlled trial, two non-randomized controlled trials, two cross-over studies, and 11 prospective cohort studies. Three reviewers independently assessed the met-hodological quality of the included studies and extracted the data. The included studies differed in design, intervention/exposure, and outcome, so meta-analysis was not carried out and qualitative results were reported. A few prospective cohort studies found that low employees’ control over worktime increases the risk of depressive symptoms, psychological distress, burnout, and accumulated fatigue. One cross-over and a few cohort studies found small beneficial effects of working partly from home on depressive symptoms, stress, and emotional exhaustion. A small number of controlled trials, cross-over or cohort studies found that flexible working arrangements increase employees’ control over working hours, but have only modest beneficial effects on psychological distress, burnout, and emotional exhaustion. This systematic review suggests that employee-oriented flexible work may have small beneficial effects on mental health. However, randomized controlled trials and quasi-experimental studies are needed to identify the health effects of flexible work.

Analysis of Factors Influencing Safety Attitudes of Operating Room Nurses and Their Cognition and Attitudes toward Adverse Event Reporting

Operating room nurses play a critical role in patient safety. The evaluation of safety attitudes of operating room nurses reflects their awareness and belief of patient safety. Currently, however, the research on the safety attitudes of operating room nurses is hard to track in the existing literature in China. Therefore, this paper was conducted to explore the factors influencing the safety attitudes of operating room nurses and their cognition and attitudes toward adverse event reporting. A total of 711 operating room nurses from 16 tertiary hospitals in Sichuan Province from March 1, 2018, to 2019 were selected. The general information of operating room nurses, such as age, gender, and years of service in the operating room, was obtained through the basic information questionnaire. The Chinese version of the Safety Attitudes Questionnaire (C-SAQ) was used to evaluate the safety attitude of operating room nurses, and the cognition and attitude of the subjects to adverse event reports were assessed through the questionnaire of cognition and attitude toward adverse event reporting. The average score of safety attitudes of operating room nurses was 4.20 ± 0.49. The two dimensions with a lower positive reaction rate of the safety attitudes of operating room nurses were stress recognition and working conditions. The main factors affecting the safety attitude of operating room nurses were night shifts, as well as cognition and attitudes toward adverse event reporting. There was a positive correlation between the total score of C-SAQ and the total score of cognition and attitudes toward adverse event reporting (P < 0.01, r = 0.445). The safety attitude of operating room nurses is at the upper-middle level, but the stress recognition and working conditions need to be improved. Through the allocation of nursing human resources, the strengthening of hospital logistics support, and the establishment of nonpunitive nursing adverse event reporting system, the operating room safety can be significantly enhanced.

The Impact of Shift Work on Occupational Health Indicators among Professionally Active Adults: A Comparative Study

The analysis of the impact of shift work on occupational health still needs further contributions. Therefore, we developed this research with the purpose of assessing the impact of shift work on occupational health indicators, namely burnout, work-engagement, occupational self-efficacy, and mental health functioning (symptoms of depression and anxiety), by comparing workers who did shift work (44.2% of participants) with workers who did not (55.8% of participants). A total of 695 Portuguese professionally active adults between 18 and 73 years of age (M_age = 37.71; SD = 12.64) participated in this study and completed a survey containing a sociodemographic questionnaire and four occupational health measures: The Burnout Assessment Tool, The Work-Engagement questionnaire (UWES), The Occupational Self-Efficacy Questionnaire, and the BSI-18 for mental health symptoms. Results showed statistically significant differences (p < 0.05) for all indicators, demonstrating that participants who worked shifts presented lower scores of work-engagement and occupational self-efficacy, and higher scores of burnout, depression, and anxiety when compared to participants who did not work shifts. Linear regressions showed that shift work explained significant but low percentages of anxiety symptoms, low work-engagement, depression symptoms, low occupational self-efficacy, and burnout. We concluded that non-standard working hours (by shifts) are detrimental to employee occupational health, by increasing the risk of anxiety and depression levels, and burnout, and by reducing work-engagement (as a well-being indicator) and occupational self-efficacy perceptions.

A Longitudinal Study of the Relationship between Shift Work and Prostate-Specific Antigen in Healthy Male Workers

As shift work has become prevalent globally, it is important to evaluate the health effects of shift work on employees. Several studies have demonstrated a positive association between shift work and prostate cancer. Therefore, we aimed to further examine the relationship between shift work and elevated prostate-specific antigen (PSA). Our study collected data from 66,817 male participants at baseline and followed up for about 6 years. We categorized shift worker status and shift schedule types. To evaluate the risk of elevated PSA on shift workers, we estimated hazard ratios using the Cox proportional hazards regression analyses. During a median follow-up of 4.1 years, 1030 participants developed elevated PSA. The multivariable-adjusted hazard ratio (HR) of elevated PSA for shift workers compared with daytime workers was 1.37 (1.04-1.80). Among shift workers, rotating shift workers (HR = 1.47, 95% CI 1.06-2.03) showed a significantly increased risk of elevated PSA compared with daytime workers. Our longitudinal study provides evidence for an association between shift work, especially rotating shift work, and elevations of PSA.

Cortisol, chronotype, and coping styles as determinants of tolerance of nursing staff to rotating shift work

Hypothalamo-pituitary-adrenal axis activity and cortisol patterns are likely to play a role in shift work tolerance, i.e., ability to adapt to shift work without suffering stress-related consequences. Yet, the evidence is scanty. Here, salivary cortisol output during night shifts and leisure days was assessed in fast-forward rotating shift work nursing staff (N = 30), and possible links with a series of variables - gender (30% male), age (M = 39.6, SEM = 1.57 y), years of service (M = 12.43, SEM = 1.48 y), BMI (M = 23.29, SEM = 0.66 Kg/m²), self-rated chronotype, sleep quality, and psycho-behavioral factors - were investigated. Main results show that cortisol output during night shifts: i) is larger in morning-oriented chronotypes, thus affected by the circadian misalignment between biological and working rhythms; ii) associates with dysfunctional coping styles at work; iii) positively correlates with diurnal cortisol secretion on leisure days, i.e., individuals with larger cortisol output during shifts display higher cortisol secretion on non-working days. Chronotype and psycho-behavioral factors explain most of the correlational weight linking cortisol output during the night shift and off-days. In conclusion, we confirm salivary cortisol testing as a suitable objective marker of occupational stress and propose it as a valuable index for monitoring shift work tolerance, in combination with chronotype. Moreover, we emphasize the importance of evaluating psycho-behavioral factors in professional settings, because these modifiable variables can be addressed with tailored psychological interventions to ameliorate poor job satisfaction, reduce work-related distress, and avoid chronic cortisol excess experienced by shift workers.