Total and cause-specific mortality of U.S. nurses working rotating night shifts

Night Shift Work Associates with All-Cause and Cause-Specific Mortality: A Large Prospective Cohort Study

BACKGROUND

Health problems associated with shift work and night shift work are gaining increasing public attention.

OBJECTIVE

To investigate the association between night shift work and the hazard of mortality.

DESIGN

Prospective cohort study.

PARTICIPANTS

A total of 283,579 individuals with paid employment or self-employment aged 37-73 years were included from the UK Biobank with a median follow-up period of 14.0 years.

MAIN MEASURES

Participants were divided into day workers and shift workers, including the frequency of night shifts, to evaluate the association between baseline work schedules and all-cause and cause-specific mortality using the Cox proportional hazards model. Additionally, 75,760 participants with work histories were assessed for the association between average frequency and cumulative years of exposure to night shift work and all-cause and cause-specific mortality.

KEY RESULTS

Compared with that of day workers, the adjusted hazard of all-cause mortality was increased by 12.0% (hazard ratio [HR], 1.12; 95% confidence interval [CI], 1.07-1.18) in shift workers, particularly in those with no or rare night shifts (approximately 16.1%; HR, 1.16; 95% CI, 1.08-1.25) and those with irregular night shifts (approximately 9.2%; HR, 1.09; 95% CI, 1.00-1.19). Moreover, a non-linear relationship was identified between cumulative night shift years and all-cause and cause-specific mortality. Only individuals who worked night shifts for 20-30 years exhibited a substantially increased hazard of all-cause (HR, 1.52; 95% CI, 1.15-2.00) and cardiovascular disease (CVD; HR, 2.08; 95% CI, 1.16-3.71) mortality.

CONCLUSIONS

Shift workers, particularly those with rare or irregular night shifts, exhibited an increased hazard of mortality. Additionally, participants who worked night shifts for 20-30 years exhibited a substantially increased hazard of all-cause and CVD mortality.

Circadian misalignment disrupts biomarkers of cardiovascular disease risk and promotes a hypercoagulable state

The circadian system regulates 24-h time-of-day patterns of cardiovascular physiology, with circadian misalignment resulting in adverse cardiovascular risk. Although many proteins in the coagulation-fibrinolysis axis show 24-h time-of-day patterns, it is not understood if these temporal patterns are regulated by circadian or behavioral (e.g., sleep and food intake) cycles, or how circadian misalignment influences these patterns. Thus, we utilized a night shiftwork protocol to analyze circadian versus behavioral cycle regulation of 238 plasma proteins linked to cardiovascular physiology. Six healthy men aged 26.2 ± 5.6 years (mean ± SD) completed the protocol involving two baseline days with 8-h nighttime sleep opportunities (circadian alignment), a transition to shiftwork day, followed by 2 days of simulated night shiftwork with 8-h daytime sleep opportunities (circadian misalignment). Plasma was collected for proteomics every 4 h across 24 h during baseline and during daytime sleep and the second night shift. Cosinor analyses identified proteins with circadian or behavioral cycle-regulated 24-h time-of-day patterns. Five proteins were circadian regulated (plasminogen activator inhibitor-1, angiopoietin-2, insulin-like growth factor binding protein-4, follistatin-related protein-3, and endoplasmic reticulum resident protein-29). No cardiovascular-related proteins showed regulation by behavioral cycles. Within the coagulation pathway, circadian misalignment decreased tissue factor pathway inhibitor, increased tissue factor, and induced a 24-h time-of-day pattern in coagulation factor VII (all FDR < 0.10). Such changes in protein abundance are consistent with changes observed in hypercoagulable states. Our analyses identify circadian regulation of proteins involved in cardiovascular physiology and indicate that acute circadian misalignment could promote a hypercoagulable state, possibly contributing to elevated cardiovascular disease risk among shift workers.

Temporal changes in cumulative mortality risks of cancer, by occupation, in the working population of Japan from 1995 to 2020: a benchmark for radiation risk comparison

The purpose of this study was to provide benchmark data for discussing the tolerability of cancer risk associated with occupational radiation exposure. It focused on differences in cancer mortality risk by occupation among Japan's working population and examined baseline cancer mortality risks and its variations from 1995 through 2020. Data were collected every five years from national vital statistics sources. By focusing on the same types of cancer among radiation induced effects, cumulative mortality risks were calculated for colorectal, lung, and breast cancer (females only) for those aged 15-74. The average cumulative mortality risk for the working population in Japan has decreased by 30%-60% over the past 25 years. Service workers and male managers were at an average risk, among all workers, while clerical workers and transportation and manufacturing workers had about half the average risk. The risks were higher for professionals and female managers, about 1.5-2 times the average for professionals and up to 5 times the average for female managers. The decrease in the average cancer mortality risk in the working population as a baseline suggests that risk tolerance in society might have changed over time. Since differences in mortality by occupation were confirmed, the usefulness of occupational data as a benchmark needs further investigation, as high-risk/low-risk occupations vary by country and region. The results of this study contribute to put radiation risks into perspective with the background risk of cancer.

Night shift work was associated with functional outcomes in acute ischemic stroke patients treated with endovascular thrombectomy

Objective

This study aimed to explore the impact of late night shift work on the functional outcomes of patients with acute ischemic stroke (AIS) treated with endovascular thrombectomy (EVT).

Methods

Consecutive AIS patients who underwent EVT between June 2019 and June 2021 were enrolled and divided into non-night shift work and night shift work groups based on their occupational histories. The primary outcome was the modified Rankin Scale score defined 3-month functional outcome. The secondary outcomes were 3-month mortality, symptomatic intracerebral hemorrhage (sICH), ICH and early recanalization.

Results

A total of 285 patients were enrolled, 35 patients (12.3%) were night shift workers, who were younger (P < 0.001) and had a significantly higher prevalence of smoking (P < 0.001), hyperlipidemia (P = 0.002), coronary heart disease (P = 0.031), and atrial fibrillation (P < 0.001). The 3-month favorable outcomes were achieved in 44.8% and 25.7% of patients in the non-night shift work and night shift work groups, respectively (adjusted odds ratio [OR]: 0.24, 95% CI: 0.10-0.57; adjusted P = 0.001). No difference was found in 3-month mortality (adjusted OR: 0.43; 95% CI: 0.14-1.25, adjusted P = 0.121), rates of ICH (adjusted OR: 0.73; 95% CI: 0.33-1.60; adjusted P = 0.430), sICH (adjusted OR: 0.75; 95% CI: 0.34-1.67; adjusted P = 0.487), or early successful recanalization (adjusted OR: 0.42; 95% CI: 0.12-1.56; adjusted P = 0.197). These results were consistent after PSM analysis.

Conclusion

Our findings suggest that late night shift work is significantly associated with unfavorable outcomes in patients with AIS after EVT.

Circadian immunity from bench to bedside: a practical guide

The immune system is built to counteract unpredictable threats, yet it relies on predictable cycles of activity to function properly. Daily rhythms in immune function are an expanding area of study, and many originate from a genetically based timekeeping mechanism known as the circadian clock. The challenge is how to harness these biological rhythms to improve medical interventions. Here, we review recent literature documenting how circadian clocks organize fundamental innate and adaptive immune activities, the immunologic consequences of circadian rhythm and sleep disruption, and persisting knowledge gaps in the field. We then consider the evidence linking circadian rhythms to vaccination, an important clinical realization of immune function. Finally, we discuss practical steps to translate circadian immunity to the patient's bedside.

Association Between the Frequency of Tooth Brushing and the Risk of Cardiovascular Disease: A Systematic Review and Meta-analysis

Several epidemiological studies suggested that frequency of tooth brushing may be associated with cardiovascular disease (CVD) risk, but the results remain inconclusive. Therefore, the aim of this study was to synthesize frequency of tooth brushing and CVD risk using meta-analysis. Science Direct, PubMed, CINAHL, and OVID were searched through October 15, 2022. The random-effects model was used to quantitatively assess the combined risk estimation. In addition, we performed the sensitivity analysis to evaluate the robustness of the study results by excluding the included studies one by one. A total of 9 cohort studies containing 10 reports with 803,019 individuals were included in the meta-analysis. Pooled results showed that compared with the lowest brushing frequency, the highest brushing frequency (relative risk = 0.85, 95% confidence interval: 0.80-0.90) significantly reduced the risk of cardiovascular disease. There was moderate heterogeneity among included studies (P = .002, I2 = 65.4%). The exclusion of any one study did not materially change the combined risk estimates. Our meta-analysis supported the hypothesis that higher frequency of tooth brushing can reduce the risk of CVD, which may have important implications for conducting research on the prevention strategies of CVD.

Examining Nurses' Perception of Shift Work and Evaluating Supportive Interventions

BACKGROUND

Health care requires a delicate equilibrium of nurse health safety and patient safety outcomes. Shift work can disrupt this balance, resulting in poor outcomes for staff and patients.

PROBLEM

Limited evidence exists on nurses' perceptions of shift work, fatigue countermeasures use, and interest in risk-mitigating interventions.

METHODS

An online survey of nurses was conducted. Survey questions assessed perceptions of shift work, use of fatigue countermeasures, and potential interventions.

RESULTS

The participants perceived multiple differences between day and night shifts when asked about their ability to complete both work- and life-oriented tasks. Use of fatigue countermeasures was more common while working night shift. Potential interventions included the use of blackout curtains, an on-site exercise facility, consulting a nutritionist, and block scheduling.

CONCLUSIONS

Health care leaders should consider nurses' perceptions and interests when incorporating initiatives to mitigate the negative effects of shift work.

Night shift work characteristics and risk of incident coronary heart disease among health care workers: national cohort study

BACKGROUND

Night work has been associated with coronary heart disease. The present study examined exposure-response relations between quantitative night work characteristics and coronary heart disease (angina pectoris or myocardial infarction) with the aim to contribute to evidence-based recommendations for low-risk night work schedules.

METHODS

We followed 100 149 night workers (80% women) and 153 882 day workers (78% women), all health care workers in Denmark with day by day payroll information on night shifts from 2007 to 2015. We analysed data with Poisson regression stratified by sex and adjusted for age, calendar year, diabetes, family history of cardiovascular disease, educational level, occupation, indicators for obesity, hypercholesterolaemia, and hypertension.

RESULTS

Female and male night workers worked on average 1.7 and 1.8 night shifts per month for an average duration of less than 4 years. During follow-up, 1198 night and 2128 day workers were hospitalized with first-time coronary heart disease. When compared with day workers, the overall incidence rate ratios for female and male night workers were 1.06 [95% confidence interval (CI): 0.97, 1.17] and 1.22 (95% CI 1.07, 1.39). Highest risks were observed in top exposure categories for several night work characteristics. However, no consistent exposure-response relations by number of monthly night shifts, cumulative night shifts, years with rotating night shifts, years with any night shift and consecutive night shifts were observed among the night workers of either sex.

CONCLUSIONS

This study of a population with low exposure to night work does not indicate that reducing extent of monthly night shifts, cumulative night shifts, years with rotating night shifts, years with any night shift and consecutive night shifts would reduce the risk of coronary heart disease.

The mediation of health-promoting lifestyle on self-perceived health status and quality of life among nurses: a cross-sectional study

BACKGROUND

Nurses with busy workloads lack the time to maintain health, leading to a decline in physical and mental health and quality of life. It is widely accepted that self-perception of health triggers health-promoting behaviors and impacts the quality of life; however, the relationship between these factors among nurses is unclear. The purpose of this study was to investigate the ability of a health-promoting lifestyle to mediate the relationship between self-perceived health and quality of life among nurses.

METHODS

A cross-sectional survey was conducted in four regional Taiwanese teaching hospitals with over 500 beds. The survey used stratified random sampling of 600 nurses who had worked for more than six months. The Self-Perceived Health Questionnaire, the Health-Promoting Lifestyle Profile, and the World Health Organization Quality of Life Scale were used to measure nurses' self-perceived health (SPH), health-promoting lifestyle (HPL), and quality of life (QoL). A Hayes PROCESS analysis and bootstrapping method were used for the mediation analysis.

RESULTS

A total of 518 nurses' data was included in the analysis. Nurses perceived their health status as less favorable than their colleagues, but frequently adopted health promotion behaviors. Nurses reported a moderate QoL. QoL and SPH were correlated (r = .33) and a high correlation between QoL and HPL (r = .64) was found. SPH and HPL both affect QoL (B = 0.077 and 0.070). SPH and HPL explained 42.6% of the variation in QoL. HPL played a partial mediation role.

CONCLUSIONS

The study confirmed that HPL has an important role in mediating nurses' SPH and QoL. Nurse administrators are advised to encourage nurses to monitor their health status and provide health promotion mechanisms to improve their quality of life.

Circadian Clock Dysregulation and Prostate Cancer: A Molecular and Clinical Overview

Circadian clock dysregulation has been implicated in various types of cancer and represents an area of growing research. However, the role of the circadian clock in prostate cancer has been relatively unexplored. This literature review will highlight the potential role of circadian clock dysregulation in prostate cancer by examining molecular, epidemiologic, and clinical data. The influence of melatonin, light, night shift work, chronotherapy, and androgen independence are discussed as they relate to the existing literature on their role in prostate cancer.

Circadian regulation of liver metabolism: experimental approaches in human, rodent, and cellular models

Circadian rhythms are endogenous oscillations with approximately a 24-h period that allow organisms to anticipate the change between day and night. Disruptions that desynchronize or misalign circadian rhythms are associated with an increased risk of cardiometabolic disease. This review focuses on the liver circadian clock as relevant to the risk of developing metabolic diseases including nonalcoholic fatty liver disease (NAFLD), insulin resistance, and type 2 diabetes (T2D). Many liver functions exhibit rhythmicity. Approximately 40% of the hepatic transcriptome exhibits 24-h rhythms, along with rhythms in protein levels, posttranslational modification, and various metabolites. The liver circadian clock is critical for maintaining glucose and lipid homeostasis. Most of the attention in the metabolic field has been directed toward diet, exercise, and rather little to modifiable risks due to circadian misalignment or disruption. Therefore, the aim of this review is to systematically analyze the various approaches that study liver circadian pathways, targeting metabolic liver diseases, such as diabetes, nonalcoholic fatty liver disease, using human, rodent, and cell biology models.NEW & NOTEWORTHY Over the past decade, there has been an increased interest in understanding the intricate relationship between circadian rhythm and liver metabolism. In this review, we have systematically searched the literature to analyze the various experimental approaches utilizing human, rodent, and in vitro cellular approaches to dissect the link between liver circadian rhythms and metabolic disease.

Wake-up Call: Night Shifts Adversely Affect Nurse Health and Retention, Patient and Public Safety, and Costs

The purpose of this mini review is to (1) summarize the findings on the impact of night shift on nurses' health and wellness, patient and public safety, and implications on organizational costs and (2) provide strategies to promote night shift nurses' health and improve organizational costs. The night shift, compared with day shift, results in poorer physical and mental health through its adverse effects on sleep, circadian rhythms, and dietary and beverage consumption, along with impaired cognitive function that increases nurse errors. Nurse administrators and health care organizations have opportunities to improve nurse and patient safety on night shifts. Low-, moderate-, and higher-cost measures that promote night nurses' health and well-being can help mitigate these negative outcomes. The provided individual and organizational recommendations and innovations support night shift nurses' health, patient and public safety, and organizational success.

The Role of the Circadian Rhythm in Dyslipidaemia and Vascular Inflammation Leading to Atherosclerosis

Cardiovascular diseases (CVD) are among the leading causes of death worldwide. Many lines of evidence suggest that the disturbances in circadian rhythm are responsible for the development of CVDs; however, circadian misalignment is not yet a treatable trait in clinical practice. The circadian rhythm is controlled by the central clock located in the suprachiasmatic nucleus and clock genes (molecular clock) located in all cells. Dyslipidaemia and vascular inflammation are two hallmarks of atherosclerosis and numerous experimental studies conclude that they are under direct influence by both central and molecular clocks. This review will summarise the results of experimental studies on lipid metabolism, vascular inflammation and circadian rhythm, and translate them into the pathophysiology of atherosclerosis and cardiovascular disease. We discuss the effect of time-respected administration of medications in cardiovascular medicine. We review the evidence on the effect of bright light and melatonin on cardiovascular health, lipid metabolism and vascular inflammation. Finally, we suggest an agenda for future research and recommend on clinical practice.

Effects of Unconventional Work and Shift Work on the Human Gut Microbiota and the Potential of Probiotics to Restore Dysbiosis

The work environment is a factor that can significantly influence the composition and functionality of the gut microbiota of workers, in many cases leading to gut dysbiosis that will result in serious health problems. The aim of this paper was to provide a compilation of the different studies that have examined the influence of jobs with unconventional work schedules and environments on the gut microbiota of workers performing such work. As a possible solution, probiotic supplements, via modulation of the gut microbiota, can moderate the effects of sleep disturbance on the immune system, as well as restore the dysbiosis produced. Rotating shift work has been found to be associated with an increase in the risk of various metabolic diseases, such as obesity, metabolic syndrome, and type 2 diabetes. Sleep disturbance or lack of sleep due to night work is also associated with metabolic diseases. In addition, sleep disturbance induces a stress response, both physiologically and psychologically, and disrupts the healthy functioning of the gut microbiota, thus triggering an inflammatory state. Other workers, including military, healthcare, or metallurgy workers, as well as livestock farmers or long-travel seamen, work in environments and schedules that can significantly affect their gut microbiota.

Effects of nurses' schedule characteristics on fatigue: An integrative review

An integrative review of 21 studies found mixed results on the associations of work schedule and nurse fatigue. Suggestions for nurse leaders include monitoring fatigue in shift workers, ensuring supportive work design, promoting a healthy lifestyle, and implementing scheduling interventions.

The Relationship between Working Night Shifts and Depression among Nurses: A Systematic Review and Meta-Analysis

BACKGROUND

For many years, occupational physicians have debated whether there is a link between working the night shift and depression and other co-occurring mental health issues, with an emphasis on work-related, biological, individual, and environmental factors. We performed this systematic review and meta-analysis to estimate the overall association between sleep deprivation and depression among nurses working night shifts.

METHODS

A systematic search was carried out across the electronic databases PubMed, Scopus, and Web of Science from inception to 30 September 2022, for studies that reported a relationship between estimated night shift work and depression in nurses. The outcomes were measured using the odds ratio (OR) and matching 95% confidence interval (CI). The I² statistic was used to assess heterogeneity. The Grading of Recommendations Assessment, Development and Evaluation technique was used to evaluate the quality of the evidence, and the Newcastle-Ottawa Scale was utilized to assess the methodological quality of each of the included studies. We determined the overall relationship between working nights and the onset of depression.

RESULTS

A total of 20 studies were included in the systematic review. Furthermore, 8 studies were included in the meta-analysis due to their common use of the OR as an effect measure. The 8 studies gave an overall estimate indicating a statistically significant association between night shift work and depression among nurses (OR = 1.49 95% CI: 1.26, 1.76). The prediction interval for the overall estimate was (0.995, 2.231). This implies that the true OR in a future study would most likely fall within this range, with a 95% certainty.

CONCLUSIONS

The outcome of this systematic review and meta-analysis showed a significant association between night shift work, the circadian and sleep disruption it causes, and the risk of depression in nurses. This demonstrates that nurses who work night shifts are at risk of developing depression.

Occupational Cancers among Employed Women: A Narrative Review

The facts that occupational cancer in women is under-investigated, with few in-depth analyses are well known. In recent decades the workforce has changed, with an increasing number of women employed. Therefore, the inclusion of women in occupational cancer studies has become more urgent and feasible than in the past decades. The difficulties to evaluate occupational causes of female gynecologic tumors in most past cohorts and the potential variation in outcome responses between men and women must be taken into consideration. This narrative review discusses women's occupational cancer as a current area of research, focusing on three groups of workers characterized by peculiar exposure to occupational carcinogens and where women are often employed: beauticians and hairdressers; farmers; and healthcare workers. We discuss the most relevant cancers in each working category, with a particular focus on female breast cancer. In the three industries reviewed in detail, there are some risk factors which may affect primarily women, inducing breast cancer and cervical cancer, as well as risk factors that are carcinogenic in both genders, but whose effects are less well known in women.

Addressing Surgeon Burnout Through a Multi-level Approach: A National Call to Action

Purpose of Review

Physician burnout is an epidemic and there are unique aspects of surgery that dictate rates of burnout among general surgeons and surgical trainees. This review characterizes the scope of burnout and its drivers within the field of surgery and advocates for strategies to address burnout at the individual, institutional, and national levels.

Recent Findings

Rates of burnout in surgery are increasing with higher numbers of young and female surgeons affected. Contributing factors are generally related to work-life balance, longer hours, and mistreatment in the workplace. Attempts have been made at implementing structured initiatives in an effort to combat work dissatisfaction and emotional exhaustion. Still, rates of burnout continue to increase.

Summary

General surgeons and trainees are at high risk for burnout with resulting attrition, depression, and suicidal ideation. The solution to burnout must be addressed at individual, institutional, and national levels. Further research into the factors leading to surgeon burnout and enactment of effective strategies to mitigate burnout must be pursued.

Mobile app for personalized sleep–wake management for shift workers: A user testing trial

Objective

Development of personalized sleep–wake management tools is critical to improving sleep and functional outcomes for shift workers. The objective of the current study was to test the performance, engagement and usability of a mobile app ( SleepSync) for personalized sleep–wake management in shift workers that aid behavioural change and provide practical advice by providing personalized sleep scheduling recommendations and education.

Methods

Shift workers ( n = 27; 20 healthcare and 7 from other industries) trialled the mobile app for two weeks to determine performance, engagement and usability. Primary outcomes were self-reported total sleep time, ability to fall asleep, sleep quality and perception of overall recovery on days off. Secondary performance outcomes included sleep disturbances (insomnia and sleep hygiene symptoms, and sleep-related impairments) and mood (anxiety, stress and depression) pre- and post-app use. Satisfaction with schedule management, integration into daily routine and influence on behaviour were used to determine engagement, while the usability was assessed for functionality and ease of use of features.

Results

Total sleep time ( P = .04), ability to fall asleep ( P < .001), quality of sleep ( P = .001), insomnia ( P = .02), sleep hygiene ( P = .01), sleep-related impairments ( P = .001), anxiety ( P = .001), and stress ( P = .006) were all improved, with non-significant improvements in recovery on days off ( P = .19) and depression ( P = .07). All measures of engagement and usability were scored positively by the majority of users.

Conclusions

This pilot trial provides preliminary evidence of the positive impact of the SleepSync app in improving sleep and mood outcomes in shift workers, and warrants confirmation in a larger controlled trial.

Understanding the determinants of circadian health disparities and cardiovascular disease

Emerging research suggests that sleep contributes to racial disparities in cardiovascular disease (CVD). Racial/ethnic minorities are disproportionately affected by poor cardiovascular outcomes including obesity, hypertension and diabetes. Although circadian rhythms affect sleep patterns, few studies have examined disparities in circadian health or the contribution of circadian disparities to CVD. In this paper, we provide an overview of the relation between circadian health and CVD in the context of health disparities. We discuss (1) the current knowledge on racial disparities in circadian health; (2) social and environmental determinants of circadian health disparities; (3) the cardiovascular consequences of circadian disparities; and (4) future opportunities to advance the field of circadian disparities. In brief, our findings demonstrated that among a small literature, racial minorities (mainly African American) were more likely to have a shorter circadian period, delayed phase shifts, and were more likely to be shift workers, which are associated with CVD risk factors. Given racial minorities are disproportionately affected by CVD and CVD risk factors, it is important to further understand circadian health as an intervention target and support more research among racial minorities to understand circadian health in these populations.

Shift work is significantly and positively associated with dementia: A meta-analysis study

Background

Shift work may disrupt the sleep and wake cycles and negatively affect physical and mental health. Dementia is a neurodegenerative disorder with progressively declining cognition that is receiving increasing attention. Studies on the association between shift work and dementia are rare. Herein, we conducted a meta-analysis to investigate the association between shift work and dementia.

Materials and methods

This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched the PubMed, Embase, and Web of Science databases using a related set of keywords. The inclusion criteria were as follows: (1) adult employees working in a factory, company, or organization; (2) exposure to shift work/non-shift work; and (3) outcome of dementia based on examination or assessment. A meta-analysis using a fixed-effects model was performed. The hazard ratio of dementia was compared between shift workers and non-shift workers.

Results

Five studies were included in the quantitative synthesis, and two were selected for further meta-analysis. A random-effects model showed a modest association between shift work and an increase in dementia cases (pooled hazard ratio = 1.13; 95% confidence interval: 1.04-1.23; p = 0.04). This association also occurred in night workers for more than 1 year.

Conclusion

Shift work and long-term night work were modestly associated with a higher risk of developing dementia. Avoiding long-term night shifts may be effective in reducing dementia risk. Further studies are required to confirm this hypothesis.

Sequence analysis of the combinations of work shifts and absences in health care - comparison of two years of administrative data

BACKGROUND

In health care, the shift work is arranged as irregular work shifts to provide operational hours for 24/7 care. We aimed to investigate working hour trends and turnover in health care via identification of time-related sequences of work shifts and absences among health care employees. The transitions between the work shifts (i.e., morning, day, evening, and night shifts), and absences (days off and other leaves) over time were analyzed and the predictors of change in irregular shift work were quantified.

METHODS

A longitudinal cohort study was conducted using employer-owned payroll-based register data of objective and day-to-day working hours and absences of one hospital district in Finland from 2014 to 2019 (n = 4931 employees). The working hour data included start and end of work shifts, any kind of absence from work (days off, sickness absence, parental leave), and employee's age, and sex. Daily work shifts and absences in 2014 and 2019 were used in sequence analysis. Generalized linear model was used to estimate how each identified sequence cluster was associated with sex and age.

RESULTS

We identified four sequence clusters: "Morning" (60% in 2014 and 56% in 2019), "Varying shift types" (22% both in 2014 and 2019), "Employee turnover" (13% in 2014 and 3% in 2019), and "Unstable employment (5% in 2014 and 19% in 2019). The analysis of transitions from one cluster to another between 2014 and 2019 indicated that most employees stayed in the same clusters, and most often in the "Varying shift types" (60%) and "Morning" (72%) clusters. The majority of those who moved, moved to the cluster "Morning" in 2019 from "Employee turnover" (43%), "Unstable employment" (46%) or "Varying shift types" (21%). Women were more often than men in the clusters "Employee turnover" and "Unstable employment", whereas older employees were more often in "Morning" and less often in the other cluster groups.

CONCLUSION

Four clusters with different combinations of work shifts and absences were identified. The transition rates between work shifts and absences with five years in between indicated that most employees stayed in the same clusters. The likelihood of a working hour pattern characterized by "Morning" seems to increase with age.

Sleep Traits, Night Shift Work and Lung Cancer Risk among Women: Results from a Population-Based Case-Control Study in France (The WELCA Study)

Circadian rhythm disruption due to night shift work and/or sleep disorders is associated with negative health outcomes including cancer. There is only scant evidence of an association with lung cancer, unlike breast and prostate cancer. We explore the role of sleep disorders and night shift work in lung cancer risk among women in a population-based case-control study, including 716 lung cancer cases and 758 controls. Multivariable logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) associated with sleep duration per day (<7 h, 7−7.9 h, ≥8 h), a summary index of sleep disorders, chronotype, and night shift work exposure metrics. When compared to women with an average sleep duration of 7−7.9 h per day, the OR was 1.39 (95% CI 1.04−1.86) in long sleepers (≥8 h) and 1.16 (95% CI 0.86−1.56) in short sleepers (<7 h). Overall, lung cancer was not associated with the sleep disorder index, nor with night shift work, regardless of the duration of night work or the frequency of night shifts. However, elevated OR associated with the sleep disorder index were found in the subgroup of current smokers. The U-shaped association of lung cancer with sleep duration was more particularly pronounced among women who worked at night ≥5 years. Our findings suggested that sleep patterns are associated with lung cancer risk in women with a potential modifying effect by night shift work duration or tobacco smoking.

Scheduling practices for pregnant emergency medicine residents

Background

Night shift work is associated with adverse pathophysiologic effects on maternal and fetal well-being. Although emergency medicine (EM) residents work frequent night shifts, there is no existing guidance for residency program directors (PDs) regarding scheduling pregnant residents. Our study assessed scheduling practices for pregnant EM residents, differences based on program and PD characteristics, barriers and attitudes toward implementing a formal scheduling policy, and PDs' awareness of literature describing adverse effects of night shifts on maternal-fetal outcomes.

Methods

We conducted an anonymous, web-based survey of U.S. EM residencies (N = 276). Quantitative data were summarized; chi-square analysis and logistic regression were used to assess relationships between program and PD characteristics and schedule accommodations. Qualitative description was used to analyze an open-ended question, organizing findings into major and minor themes.

Results

Of the 167 completed surveys (response rate 61%), 67% of programs reported no formal policy for scheduling pregnant residents but made adjustments on an individual basis including block changes (85%), decreased (46%) or no night shifts (34%), and working shifts earlier in pregnancy to cover later shifts (20%). Barriers to adjustments included staffing constraints (60%), equity concerns (45%), or impact on wellness (41%) among all residents and privacy (28%). PDs endorsed scheduling adjustments as important (mean 8.1, 0-10 scale) and reported guidance from graduate medical education governance would be useful (60%). Larger program size, but not PD gender or proportion of female residents, was associated with an increased likelihood of scheduling modifications. Twenty-five percent of PDs reported little knowledge of literature regarding night shift work and pregnancy. Qualitative themes supported quantitative findings.

Conclusions

Most EM residency programs do not have formal scheduling policies for pregnant residents, but most PDs support making adjustments and do so informally. More education and guidance for PDs are needed to promote the development of formal policies.

Potential role of melatonin in prevention and treatment of lung cancer

Lung cancer is the second most common cancer and the most lethal cancer worldwide. Melatonin, an indoleamine produced in the pineal gland, shows anticancer effects on a variety of cancers, especially lung cancer. Herein, we clarify the pathophysiology of lung cancer, the association of circadian rhythm with lung, and the relationship between shift work and the incidence of lung cancer. Special focus is placed on the role of melatonin receptors in lung cancer, the relationship between inflammation and lung cancer, control of cell proliferation, apoptosis, autophagy, and immunomodulation in lung cancer by melatonin. A review of the drug synergy of melatonin with other anticancer drugs suggests its usefulness in combination therapy. In summary, the information compiled may serve as a comprehensive reference for the various mechanisms of action of melatonin against lung cancer, as a guide for the design of future experimental research and for advancing melatonin as a therapeutic agent for lung cancer.

Association between work characteristics and epigenetic age acceleration: cross-sectional results from UK - Understanding Society study

Occupation-related stress and work characteristics are possible determinants of social inequalities in epigenetic aging but have been little investigated. Here, we investigate the association of several work characteristics with epigenetic age acceleration (AA) biomarkers. The study population included employed and unemployed men and women (n = 631) from the UK Understanding Society study. We evaluated the association of employment and work characteristics related to job type, job stability; job schedule; autonomy and influence at work; occupational physical activity; and feelings regarding the job with four epigenetic age acceleration biomarkers (Hannum, Horvath, PhenoAge, GrimAge) and pace of aging (DunedinPoAm, DunedinPACE). We fitted linear regression models, unadjusted and adjusted for established risk factors, and found the following associations for unemployment (years of acceleration): HorvathAA (1.51, 95% CI 0.08, 2.95), GrimAgeAA (1.53, 95% CI 0.16, 2.90) and 3.21 years for PhenoAA (95% CI 0.89, 5.33). Job insecurity increased PhenoAA (1.83, 95% CI 0.003, 3.67), while working at night was associated with an increase of 2.12 years in GrimAgeAA (95% CI 0.69, 3.55). We found effects of unemployment to be stronger in men and effects of night shift work to be stronger in women. These results provide evidence of associations between unemployment with accelerated ageing and suggest that insecure employment and night work may also increase age acceleration. Our findings have implications for policies relating to current changes in working conditions and highlight the utility of biological age biomarkers in studies in younger populations without long-term health information.

Police officers' work-life balance, job satisfaction and quality of life: longitudinal effects after changing the shift schedule

OBJECTIVES

To evaluate mental health-related outcomes of police officers 5.5 years after implementing a new alternating shift schedule which was supposed to improve their health and work-life balance.

DESIGN

Pre-post study design with a baseline survey at the beginning of the piloting of the new shift schedule in 2015 and another survey 5.5 years later in 2020.

SETTING

Police departments of a German metropolitan police force piloting the new shift schedule.

PARTICIPANTS

116 shift-working police officers out of a population of 1673 police officers at the follow-up date.

INTERVENTIONS

New shift schedule based on occupational health recommendations.

OUTCOMES MEASURES

Work-life balance, job satisfaction and quality of life.

METHODS

Mixed analyses of variances were used to test the hypotheses of within-subject and between-subject differences regarding time and gender.

RESULTS

We found partly significant differences between the baseline and follow-up survey for work-life balance (F(1, 114) = 6.168, p=0.014, ηp² = 0.051), job satisfaction (F(1, 114) = 9.921, p=0.002, ηp² = 0.080) and quality of life (F(1, 114) = 0.593, p=0.443, ηp² = 0.005). Neither significant differences between male and female police officers nor interaction effects of time and gender were found.

CONCLUSION

An increase was found for each of the three outcomes 5.5 years after implementing the new shift schedule. The results contribute to the current state of research on mental health-related outcomes of working conditions in shift work. On this basis, recommendations for designing shift schedules can be deduced to promote mental health and job satisfaction for employees in shift work.

Shift Work and the Risk of Cardiometabolic Multimorbidity Among Patients With Hypertension: A Prospective Cohort Study of UK Biobank

Background Although the association between shift work and individual cardiometabolic diseases has been well studied, its role in the progression to cardiometabolic multimorbidity (CMM) remains unclear. In this study, we investigate the association between shift work and the incidence of CMM in patients with hypertension. Methods and Results This study is a population-based and prospective cohort study on 36 939 UK Biobank participants. We used competing risk models to examine the association between shift work and the risk of CMM, which was defined as coexistence of hypertension and diabetes, coronary heart disease, or stroke in our study. We also investigated the association between the frequency and duration of shift work and CMM risks. In addition, we conducted a cross-classification analysis with the combination of frequency and duration of shift work, chronotype and sleep duration as the exposure metrics. During a median follow-up of 11.6 years, a total of 5935 participants developed CMM. We found that usually/always night shift workers were associated with a 16% higher risk of CMM compared with day workers (hazard ratio [HR], 1.16 [95% CI, 1.02-1.31]). We also found that a higher frequency of night shifts (>10/month) was associated with increased risk of CMM (HR, 1.19 [95% CI, 1.06-1.34]) that was more pronounced for >10/month in combination with a morning chronotype or <7 hours or >8 hours of sleep duration (HR, 1.26 [95% CI, 1.02-1.56]; HR, 1.43 [95% CI, 1.19-1.72], respectively). Conclusions We find that night shift work is associated with higher CMM risk in patients with hypertension.

Comparison of adult shift and non-shift workers’ physical activity and sleep behaviours: cross-sectional analysis from the Household Income and Labour Dynamics of Australia (HILDA) cohort

Aim

This study compares the pattern of physical activity and sleep between shift and non-shift workers using a novel physical activity–sleep index. By drawing from a diverse occupational population, this research aims to reduce any occupational specific biases which are prevalent in shift-work research.

Subject and methods

Current data included 7607 workers (shift workers n = 832) from the Household Income and Labour Dynamics of Australia cohort study. The combined physical activity–sleep index comprised three physical activity components and three sleep health components: achieving moderate (1pt) or high (2pts) IPAQ classification; accruing ≥30% of physical activity as vigorous intensity (1pt); meeting sleep duration recommendations on a work night (1pt); and non-work night (1pt); and reporting no insomnia symptoms (1pt) (higher score = healthy behaviour, max. 6). Generalised linear modelling was used to compare behaviours of shift and non-shift workers.

Results

Findings showed shift workers reported significantly lower activity–sleep scores (3.59 vs 3.73, p < 0.001), lower sleep behaviour sub-score (2.01 vs. 2.22, p < 0.001) and were more likely to report insomnia symptoms (p < 0.001) compared to non-shift workers. No difference was reported for overall physical activity (shift = 1.58 vs. non-shift = 1.51, p = 0.383).

Conclusion

When viewed in conjunction using the combined activity–sleep index, shift workers displayed significantly poorer combined behaviours when compared to non-shift workers.

Work Conditions of Italian Nurses and Their Related Risk Factors: A Cohort Investigatory Study

(1) Background: Nursing is a satisfying employment pathway, as nurses preserve lives, but it is also considered one of the most stressful care professions. Nursing is a lifesaving and highly satisfying profession, yet it is considered one of the most stressful occupations. This study aimed to assess differences in anxiety, depression and stress states among nurses according to gender, work history, shift and body mass index (BMI) characteristics. (2) Methods: An online questionnaire was addressed to all Italian nurses during May 2022, investigating anxiety, depression and stress conditions according to the Depression, Anxiety and Stress Scale-21 Items (DASS-21) and sampling characteristics, such as sex, work experience, shift and BMI values. (3) Results: A total of 408 Italian nurses answered the questionnaire. Significant differences between the following were reported: anxiety levels and work experience, since nurses employed over 6 years reported higher anxiety levels than their younger colleagues (p = 0.035); depression levels and sex (p = 0.017), as females reported higher depression levels than males; and also between depression levels and BMI levels (p = 0.003), as 5.90% of overweight and 2.50% of obese participants reported extremely severe depression. By considering stress levels according to sampling characteristics, significant differences were registered according to BMI levels (p < 0.001), as overweight subjects reported higher stress levels (7.40%) than the other subgroups. Finally, significant associations were recorded between anxiety, depression and stress conditions with sex, work experience, shift and BMI. (4) Conclusions: The data were in agreement with the current literature, indicating that nurses might take care not only of their patients but also of themselves, in both the physical and mental aspects.

Work Exposures and Development of Cardiovascular Diseases: A Systematic Review

INTRODUCTION

Cardiovascular diseases (CVDs) are the number one cause of death, and there is evidence that work exposures could be associated with their development. This study aimed to systematically review observational studies of adults exposed to job strain, effort-reward imbalance, long working hours, job insecurity, shift work, and occupational noise, and assess the association of those work exposures with CVDs.

METHODS

The Navigation Guide framework was applied. The population were adults of working age (18-65), and cohort and case-control studies were included. The work exposures were job strain, effort-reward imbalance, long working hours, job insecurity, shift work, and occupational noise. The outcomes were cerebrovascular diseases, ischaemic heart disease, and hypertensive diseases. The selection, data extraction, risk of bias assessment, and quality assessment were carried out by two reviewers independently and disagreements were solved by a third reviewer or by consensus. The synthesis of the results was done by applying the 'vote counting based on direction' method, and the results were summarized in an effect direction plot. The strength of the evidence for every risk factor and CVD was defined by consensus.

RESULTS

A total of 17 643 papers were initially identified in the literature search, but after applying the filters by title and abstract, and full text, 86 studies were finally included. From the included studies, sufficient evidence was found of the harmfulness of job strain for cerebrovascular disease and ischemic heart disease. Furthermore, there was sufficient evidence of the harmfulness of shift work for ischemic heart disease. Evidence of no relationship was found between long working hours and shift work with ischaemic heart disease and hypertensive disease, respectively. The other associations of work exposures and CVDs had limited or inadequate evidence of harmfulness.

CONCLUSIONS

In this comprehensive review, there was sufficient evidence of a harmful relationship between job strain, shift work, and CVDs. For the other work exposures, more high-quality studies are needed. In order to improve current prevention strategies for CVDs, the findings of this review imply that job strain and shift work are work exposures that constitute additional risk factors that could be approached as targets for worksite interventions.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020179972.

Rotating Night Shift Work and Healthy Aging After 24 Years of Follow-up in the Nurses' Health Study

Importance

Rotating night shift work is associated with higher mortality. Whether it is also associated with overall health among those who survive to older ages remains unclear.

Objective

To examine whether rotating night shift work is associated with healthy aging after 24 years of follow-up in the Nurses' Health Study, a cohort study among registered female nurses.

Design, Setting, and Participants

For this cohort study, a composite healthy aging phenotype was ascertained among 46 318 participants who were aged 46 to 68 years and free of major chronic diseases in 1988 when the history of night shift work was assessed. In a secondary analysis in which cognitive function decline was considered in the healthy aging definition, 14 273 nurses were involved. Data were analyzed from March 1 to September 30, 2021.

Exposures

Duration of rotating night shift work.

Main Outcomes and Measures

Healthy aging was defined as reaching at least 70 years of age and being free of 11 major chronic diseases, memory impairment, physical limitation, or deteriorated mental health.

Results

Of 46 318 female nurses (mean [SD] age at baseline, 55.4 [6.1] years), 3695 (8.0%) achieved healthy aging after 24 years of follow-up. After adjusting for established and potential confounders, compared with women who never worked rotating night shifts, the odds of achieving healthy aging decreased significantly with increasing duration of night shift work. The odds ratios were 0.96 (95% CI, 0.89-1.03) for 1 to 5 years, 0.92 (95% CI, 0.79-1.07) for 6 to 9 years, and 0.79 (95% CI, 0.69-0.91) for 10 or more years of night shift work (P = .001 for trend). This association did not differ substantially by age and lifestyles and was consistent for 4 individual dimensions of healthy aging. Results were similar in a secondary analysis, with an odds ratio of 0.73 (95% CI, 0.60-0.89; P < .001 for trend) comparing 10 or more years of night shift work vs no night shift work.

Conclusions and Relevance

In this cohort study, rotating night shift work was associated with decreased probability of healthy aging among US female nurses. These data support the notion that excess night shift work is a significant health concern that may also lead to deteriorated overall health among older individuals.

Impact of Rotating Shifts on Lifestyle Patterns and Perceived Stress among Nurses: A Cross-Sectional Study

Although rotating shifts have a negative health impact, their association with hospital nurses’ health risks remains controversial due to incomplete adjustment in lifestyle patterns and heterogeneity of work schedules. However, whether work schedule characteristics are associated with lifestyle patterns and perceived stress remains undetermined. We assessed the correlations of work schedule characteristics, lifestyle patterns, and perceived stress among hospital nurses. This cross-sectional study included 340 nurses from two hospitals. Final data from 329 nurses regarding work schedule characteristics, lifestyle patterns (physical activity, dietary behavior, and sleep pattern), and perceived stress were analyzed via linear regression models. Fixed-day-shift nurses had reduced perceived stress (β = 0.15, p = 0.007) compared with rotating-shift nurses. Additionally, among rotating-shift nurses, fixed-evening- and fixed-night-shift nurses had longer sleep duration (β = 0.27, p < 0.001; β = 0.25, p < 0.001) compared to non-fixed-rotating-shift nurses. Longer rotating-shift work was associated with healthier dietary behaviors (β = 0.15, p = 0.008), better sleep quality (β = −0.17, p = 0.003), lower perceived stress (β = −0.24, p < 0.001), and shorter sleep duration (β = −0.17, p = 0.003). Hospital nurses’ work schedule characteristics were associated with lifestyle patterns, dietary behavior, sleep pattern, and perceived stress. Fixed-shifts were beneficial for lifestyle and lower perceived stress. Longer rotating shifts could help nurses adjust their lifestyles accordingly.

The Role of Race, Sex, and Age in Circadian Disruption and Metabolic Disorders

Circadian rhythms are 24-hour internal biological cycles that play an important role in metabolism, and their disruption has been implicated in the development of diseases such as diabetes mellitus type 2, obesity, coronary artery disease, hypertension, and metabolic syndrome. This phenomenon is illustrated by increased rates of risk factors for cardiovascular disease in night shift workers. Race, sex, and age are factors that play a role in circadian rhythms and metabolic disorders. The focus of this review article is to assess the link between circadian rhythm physiology and metabolic disorders from a race, sex, and age perspective. Black Americans were noted to have shorter free-running circadian periods, or tau, increased cortisol levels, and poorer sleep habits compared to white Americans, possibly contributing to increased rates of obesity, hypertension, and hyperlipidemia. Women were also noted to have shorter tau, increased levels of proinflammatory gut bacteria, and reduced sleep quality compared to men, possibly leading to higher rates of obesity, metabolic syndrome, hypertension (in postmenopausal women), and nonalcoholic fatty liver disease. Older people were noted to have decreased expression of anti-inflammatory clock genes compared to younger people, possibly leading to increased rates of obesity, diabetes, hyperlipidemia, and hypertension. Groups that are at a higher risk for metabolic disorders such as black Americans, women, and the elderly may have internal time keeping systems that place them at a higher risk for developing abnormal hormonal and/or inflammatory pathways.

Lack of food intake during shift work alters the heart transcriptome and leads to cardiac tissue fibrosis and inflammation in rats

Background

Many epidemiological studies revealed that shift work is associated with an increased risk of a number of pathologies, including cardiovascular diseases. An experimental model of shift work in rats has additionally been shown to recapitulate aspects of metabolic disorders observed in human shift workers, including increased fat content and impaired glucose tolerance, and used to demonstrate that restricting food consumption outside working hours prevents shift work-associated obesity and metabolic disturbance. However, the way distinct shift work parameters, such as type of work, quantity, and duration, affect cardiovascular function and the underlying mechanisms, remains poorly understood. Here, we used the rat as a model to characterize the effects of shift work in the heart and determine whether they can be modulated by restricting food intake during the normal active phase.

Results

We show that experimental shift work reprograms the heart cycling transcriptome independently of food consumption. While phases of rhythmic gene expression are distributed across the 24-h day in control rats, they are clustered towards discrete times in shift workers. Additionally, preventing food intake during shift work affects the expression level of hundreds of genes in the heart, including genes encoding components of the extracellular matrix and inflammatory markers found in transcriptional signatures associated with pressure overload and cardiac hypertrophy. Consistent with this, the heart of shift worker rats not eating during work hours, but having access to food outside of shift work, exhibits increased collagen 1 deposition and displays increased infiltration by immune cells. While maintaining food access during shift work has less effects on gene expression, genes found in transcriptional signatures of cardiac hypertrophy remain affected, and the heart of shift worker rats exhibits fibrosis without inflammation.

Conclusions

Together, our findings unraveled differential effects of food consumption on remodeled transcriptional profiles of the heart in shift worker rats. They also provide insights into how shift work affects cardiac function and suggest that some interventions aiming at mitigating metabolic disorders in shift workers may have adverse effects on cardiovascular diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-022-01256-9.

Night shift work and lymphoma: results from an Italian multicentre case-control study

BACKGROUND

Night shift work can disrupt circadian rhythm and cause chronic sleep deprivation, which might increase the risk of lymphoma through immunosuppression and oxidative stress.

MATERIAL AND METHODS

We investigated the association between night shift work and risk of lymphoma subtypes in 867 incident cases and 774 controls, who participated in a multicentre Italian study between 2011 and 2017. Based on questionnaire information, occupational experts assessed the lifetime probability of night shift work, the total number of night shifts and years of night shift work among study participants. OR and 95% CI for lymphoma and its major subtypes associated with night shift work was calculated with logistic regression, adjusting by age, gender, education, study area, marital status and family history of haemolymphatic cancer.

RESULTS

Ever working night shifts was associated with an increase in the risk of chronic lymphocytic leukaemia (CLL) (OR 1.9, 95% CI 1.14 to 3.32), which was highest after a 15-34 years latency. However, there was not a linear increase in risk by probability of exposure, years of night shift work, nor lifetime number of night shifts whether under rotating or permanent work schedules. Risk of lymphoma overall, B cell lymphoma (BCL), its major subtypes other than CLL, and other less prevalent BCL subtypes combined did not show an association.

CONCLUSIONS

We found conflicting evidence of an association between night shift work and the risk of CLL. We did not observe an association with other lymphoma subtypes.

Potential effects of shift work on skin autoimmune diseases

Shift work is associated with systemic chronic inflammation, impaired host and tumor defense and dysregulated immune responses to harmless antigens such as allergens or auto-antigens. Thus, shift workers are at higher risk to develop a systemic autoimmune disease and circadian disruption with sleep impairment seem to be the key underlying mechanisms. Presumably, disturbances of the sleep-wake cycle also drive skin-specific autoimmune diseases, but epidemiological and experimental evidence so far is scarce. This review summarizes the effects of shift work, circadian misalignment, poor sleep, and the effect of potential hormonal mediators such as stress mediators or melatonin on skin barrier functions and on innate and adaptive skin immunity. Human studies as well as animal models were considered. We will also address advantages and potential pitfalls in animal models of shift work, and possible confounders that could drive skin autoimmune diseases in shift workers such as adverse lifestyle habits and psychosocial influences. Finally, we will outline feasible countermeasures that may reduce the risk of systemic and skin autoimmunity in shift workers, as well as treatment options and highlight outstanding questions that should be addressed in future studies.

Night-shift work, breast cancer incidence, and all-cause mortality: an updated meta-analysis of prospective cohort studies

OBJECTIVES

Night-shift work exposure is proposed to link to a wide range of health issues, especially cancer incidence, cancer-specific death, and all-cause death. However, the epidemiological associations among night-shift work exposure, breast cancer, breast cancer-specific death, and all-cause mortality remain inconclusive.

METHODS

We performed an updated systematic review and meta-analysis to confirm potential associations among night-shift work exposure, breast cancer, and all-cause mortality.

RESULTS

A total of 31 prospective cohort studies, involving 9.3 million participants, 31,244 incident breast cancer cases, 12,728 cancer-related deaths, 7882 cardiovascular deaths, and 30,807 all-cause mortalities were included. Overall, the summary RR of incident breast cancer in females for an increase of night-shift work was 1.029 (95% CI 1.003-1.055). Compared with standard day workers, night-shift workers had a statistically significantly increased RR (1.086, 95% CI 1.032-1.142) for breast cancer incidence in the subgroup of > 10 years exposure. Furthermore, a positive association was revealed in subgroup studies of rotating night-shift work (RR = 1.053, 95% CI 1.018-1.090). A significant increased risk of cardiovascular mortality was demonstrated in the night-shift work group (RR = 1.031; 95% CI 1.006-1.057).

CONCLUSION

Our systematic review and meta-analysis provided convincing evidence supporting positive associations among night-shift work exposure, breast cancer incidence, and cardiovascular mortality. Taken together, night-shift work exposure significantly increased the risk of breast cancer morbidity by 2.9% for total, 8.6% for the subgroup of more than 10 years night-shift work, and 5.3% for rotating night-shift work. In addition, night-shift work increased the risk of cardiovascular mortality by 3.1%.

Long-term night shift work is associated with the risk of atrial fibrillation and coronary heart disease

AIMS

The aim of this study was to test whether current and past night shift work was associated with incident atrial fibrillation (AF) and whether this association was modified by genetic vulnerability. Its associations with coronary heart disease (CHD), stroke, and heart failure (HF) were measured as a secondary aim.

METHODS AND RESULTS

This cohort study included 283 657 participants in paid employment or self-employed without AF and 276 009 participants free of CHD, stroke, and HF at baseline in the UK Biobank. Current and lifetime night shift work information was obtained. Cox proportional hazard models were used. Weighted genetic risk score for AF was calculated. During a median follow-up of 10.4 years, 5777 incident AF cases were documented. From 'day workers', 'shift but never/rarely night shifts', and 'some night shifts' to 'usual/permanent night shifts', there was a significant increasing trend in the risk of incident AF (P for trend 0.013). Usual or permanent night shifts were associated with the highest risk [hazard ratio (HR) 1.16, 95% confidence interval (CI) 1.02-1.32]. Considering a person's lifetime work schedule and compared with shift workers never working nights, participants with a duration over 10 years and an average 3-8 nights/month frequency of night shift work exposure possessed higher AF risk (HR 1.18, 95% CI 0.99-1.40 and HR 1.22, 95% CI 1.02-1.45, respectively). These associations between current and lifetime night shifts and AF were not modified by genetic predisposition to AF. Usual/permanent current night shifts, ≥10 years and 3-8 nights/month of lifetime night shifts were significantly associated with a higher risk of incident CHD (HR 1.22, 95% CI 1.11-1.35, HR 1.37, 95% CI 1.20-1.58 and HR 1.35, 95% CI 1.18-1.55, respectively). These associations in stroke and HF were not significant.

CONCLUSION

Both current and lifetime night shift exposures were associated with increased AF risk, regardless of genetic AF risk. Night shift exposure also increased the risk of CHD but not stroke or HF. Whether decreasing night shift work frequency and duration might represent another avenue to improve heart health during working life and beyond warrants further study.

Can Night Shift Work Affect Biological Age? Hints from a Cross-Sectional Study on Hospital Female Nurses

Disruption of age-related processes seems to play a relevant role in health effects related to night shift (NS) work. We aim to verify whether NS work can influence biological age (BA), estimated through Zbieć-Piekarska's epigenetic signature, based on methylation of five CpG sites in ELOVL2, C1orf132/MIR29B2C, TRIM59, KLF14, and FHL2. Forty-six female nurses working in NS were matched by age and length of employment with 51 female colleagues not working in NS. Each subject filled in a questionnaire (including the Effort Reward Imbalance (ERI) index to assess job stress) and gave a blood sample. Age acceleration (AA) was estimated by regressing BA on chronological age and taking the residuals. Multivariate linear regression models were applied. BA was not associated with NS. However, we did observe an increase in AA per each year in NS in subjects with overweight/obesity (β = 0.46, 95% CI: 0.05; 0.87, p = 0.03), experiencing work-related stress (β = 0.58, 95% CI: 0.10; 1.06, p = 0.018), or both (β = 0.66, 95% CI: 0.03; 1.29, p = 0.041). Although based on a small sample size, our findings suggest an increased BA only among hypersusceptible subjects and is worth further investigation, also in light of recent results suggesting a higher breast cancer risk in women with increased AA.

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

BACKGROUND

Epidemiological 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.

METHODS

Embase, 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.

RESULTS

We 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.

CONCLUSION

Night 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.

Improving Diuretic Response in Heart Failure by Implementing a Patient-Tailored Variability and Chronotherapy-Guided Algorithm

Heart failure is a major public health problem, which is associated with significant mortality, morbidity, and healthcare expenditures. A substantial amount of the morbidity is attributed to volume overload, for which loop diuretics are a mandatory treatment. However, the variability in response to diuretics and development of diuretic resistance adversely affect the clinical outcomes. Morevoer, there exists a marked intra- and inter-patient variability in response to diuretics that affects the clinical course and related adverse outcomes. In the present article, we review the mechanisms underlying the development of diuretic resistance. The role of the autonomic nervous system and chronobiology in the pathogenesis of congestive heart failure and response to therapy are also discussed. Establishing a novel model for overcoming diuretic resistance is presented based on a patient-tailored variability and chronotherapy-guided machine learning algorithm that comprises clinical, laboratory, and sensor-derived inputs, including inputs from pulmonary artery measurements. Inter- and intra-patient signatures of variabilities, alterations of biological clock, and autonomic nervous system responses are embedded into the algorithm; thus, it may enable a tailored dose regimen in a continuous manner that accommodates the highly dynamic complex system.

Comparison of Psychological and Physiological Stress in NICU Nurses: Effects of Unit Design and Shift

BACKGROUND

Effects of unit design and shift worked on stress in neonatal intensive care unit (NICU) nurses have not been fully studied.

PURPOSE

To compare stress in NICU nurses who work in single-family room (SFR) or open bay (OBY) units and on nonrotating day or night shift.

METHODS

Full-time registered nurses (RNs) (n = 72) from a 42-bed SFR and a 131-bed OBY NICU participated in this comparative cross-sectional study. The Nurse Stress Scale (NSS) and within-shift repeated salivary cortisol levels were used to measure stress. The relationship between NSS score and salivary cortisol level was examined using multiple linear regression. Salivary cortisol levels of day versus night shift were compared with mixed-effects linear models.

RESULTS

NSS scores were similar for SFR and OBY units (P = .672) and day versus night shift (P = .606). Changes in cortisol level over time (P = .764) and final cortisol level (P = .883) for SFR versus OBY were not significantly different after controlling for shift. Salivary cortisol level of day-shift nurses decreased significantly over time compared with night-shift nurses (P < .001). The final cortisol level was significantly higher for night-shift compared with day-shift nurses (P < .001).

IMPLICATIONS FOR PRACTICE

Psychological (NSS) and physiologic (salivary cortisol) stress of NICU nurses is similar in established SFR and OBY units. Cortisol levels are higher at the end of shift in nurses who work night shift and may reflect increased physiologic stress.

IMPLICATIONS FOR RESEARCH

Strategies are needed for reducing stress in NICU nurses who work night shift.

The linkage "Body Mass Index-Insomnia Levels-Eating Disorder Flexibility" in Italian nurses during the Covid-19 outbreak: a psychoendocrinological employment disease

AIM

To evaluate differences between insomnia condition and flexibility attitude to eating in Italian nurses directly involved in the care of patients affected by Covid-19 according to sex, Body Mass Index, shift working condition and incidence of new Covid-19 cases in the region of participants. Moreover, any correlations between the insomnia condition and the flexible attitude to eat have been investigated.

METHODS

An online questionnaire was administered in October 2020, including the socio-demographic section, the insomnia condition assessment, and the behavioral flexibility evaluation to develop an eating disorder.

RESULTS

341 Italian nurses answered the questionnaire. Regarding the insomnia condition levels, nurses belonging to regions with a higher incidence rate of the Covid-19 pandemic recorded higher levels of insomnia than others (p=.004). Females and nurses belonging to areas with lower Covid-19 incidence rate recorded a significantly higher total eating flexibility attitude (p=.003; p<.001), also, in the Food and Exercise flexibility (p=.007; p<.001). As regards the flexible attitude for weight and shape, significant differences were recorded among nurses according to their BMI values (p<.001) and to their incidence rate of the belonging region (p<.001). The insomnia condition levels significantly correlated with the eat flexibility attitude both in its total score (p=.010), in the general score (p=.010), and the weight and shape score (p<.001). All correlations between the insomnia conditions and the flexibility to eat were significantly inverse except for the food and exercise dimension. All the eat flexibility sub-dimensions significantly correlated among them (p<.001).

CONCLUSION

There was a direct correlation among socio-demographic factors, BMI values, insomnia, and behavioral flexibility scores in Italian nurses. So, it could be assumed that the nursing profession is at risk of developing a metabolic syndrome condition. Therefore, it could be considered a psychoendocrinological employment disease during the Covid-19 outbreak.

The Impact of Stress Within and Across Generations: Neuroscientific and Epigenetic Considerations

The impact of stress and trauma on biological systems in humans can be substantial. They can result in epigenetic changes, accelerated brain development and sexual maturation, and predisposition to psychopathology. Such modifications may be accompanied by behavioral, emotional, and cognitive overtones during one's lifetime. Exposure during sensitive periods of neural development may lead to long-lasting effects that may not be affected by subsequent environmental interventions. The cumulative effects of life stressors in an individual may affect offspring's methylome makeup and epigenetic clocks, neurohormonal modulation and stress reactivity, and physiological and reproductive development. While offspring may suffer deleterious effects from parental stress and their own early-life adversity, these factors may also confer traits that prove beneficial and enhance fitness to their own environment. This article synthesizes the data on how stress shapes biological and behavioral dimensions, drawing from preclinical and human models. Advances in this field of knowledge should potentially allow for an improved understanding of how interventions may be increasingly tailored according to individual biomarkers and developmental history.

Subjective cognitive abilities correlate with poor sleep among day-shift and night-shift nurses

Experimental studies have shown that sleep deprivation may lead to worse performance on cognitive tests. However, few studies have considered how sleep is associated with perceived cognitive performance in the daily lives of hospital nurses who require high cognitive abilities to deliver high-quality patient care. The current study examined the relationship between sleep and subjective cognition in nurses, and whether the relationship differed by work shift and workdays. Sixty in patient nurses working full-time (M = 35 years; 39 day-shift nurses, 21 night-shift nurses) reported their sleep characteristics and daily subjective cognition using ecological momentary assessment for 14 days. Concurrently, objective sleep characteristics were measured with a sleep actigraphy device for 14 days. Using multilevel modelling, results indicated that at the within-person and between-person level, better sleep quality and higher sleep sufficiency were associated with better subjective cognition at the daily-level and on average. Moderation analyses indicated at the within-person level, better sleep quality and longer time in bed were associated with better next-day cognition; these associations were stronger for night-shift nurses compared with day-shift nurses. At the between-person level, better sleep quality and higher sleep sufficiency were also associated with better subjective cognition overall; these associations were significant for day-shift nurses, but not for night-shift nurses. The sleep-subjective cognition relationships were more apparent on workdays versus non-workdays. Findings suggest that sufficient sleep recovery is important for nurses' reports of daily and overall cognitive functioning. Night-shift nurses' subjective cognitive abilities may be more protected on days following better sleepquality and more sufficient sleep.