Examining Exposure Assessment in Shift Work Research: A Study on Depression Among Nurses

Sleep regulation and host genetics

Due to the multifactorial and complex nature of rest, we focus on phenotypes related to sleep. Sleep regulation is a multifactorial process. In this chapter, we focus on those phenotypes inherent to sleep that are highly prevalent in the population, and that can be modulated by lifestyle, such as sleep quality and duration, insomnia, restless leg syndrome and daytime sleepiness. We, therefore, leave in the background those phenotypes that constitute infrequent pathologies or for which the current level of scientific evidence does not favour the implementation of practical approaches of this type. Similarly, the regulation of sleep quality is intimately linked to the regulation of the circadian rhythm. Although this relationship is discussed in the sections that require it, the in-depth study of circadian rhythm regulation at the molecular level deserves a separate chapter, and this is how it is dealt with in this volume.

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.

Shift Work Domains and their Interactions with Empty Calorie Food/Beverage Consumption: A 14-day Intensive Longitudinal Study

BACKGROUND/OBJECTIVES

Shift work has been linked to unhealthy eating behaviors such as imbalanced diet, or increased empty calorie food/beverage consumption. However, most research has focused on the impact of shift timing. The concept of shift work is complex, and it contains several domains such as shift timing, intensity, and speed. Previous studies have suggested that greater shift intensity and quicker shift speed may contribute to adverse health effects. However, evidence regarding associations between other domains of shift work and empty calorie food/beverage consumption has been relatively lacking. Therefore, the purpose of this study was to evaluate how other shift work domains related to empty calorie food/beverage consumption and whether different shift work domains interacted to influence the intake of foods or beverages.

DESIGN

A 14-day intensive longitudinal study employing ecological momentary assessment.

SETTINGS AND PARTICIPANTS

Eighty registered nurses working in 24 accredited Taiwanese hospitals (i.e., 9 medical centers, 12 regional hospitals, and 3 district hospitals) were recruited.

METHODS

During the study period, a convenience sample of 77 participants completed 2444 momentary surveys about empty calorie food/beverage consumption on a smartphone. Three shift work domains (shift timing, intensity, and speed) were evaluated based on registry-based work schedules. To study how these shift work domains influenced empty calorie food/beverage consumption, we employed three-level mixed-effects regression models for data analyses.

RESULTS

Findings suggested that greater night shift intensity increased the likelihood of sugar-sweetened beverage intake (odds ratio = 1.64, 95% confidence interval [1.01, 2.68]). The impacts of work shift intensity and shift timing on sugar-sweetened beverage consumption varied by shift speed. Among participants assigned a schedule with either medium or rapid shift speed, higher work shift intensity was associated with a higher probability of sugar-sweetened beverage consumption. Compared to day shifts, those who were assigned a quicker shift speed on evening shifts were more likely to consume sugar-sweetened beverages. However, associations between night shift intensity and sugar-sweetened beverage intake did not change by shift speed. Furthermore, shift intensity and shift timing did not interact to affect empty calorie food/beverage consumption.

CONCLUSIONS

This study demonstrated assignments of shift schedules (i.e., high night shift intensity, more changes in shift timings) might influence workers' consumption of empty calorie foods/beverages. Therefore, identifying and mitigating hazardous shift schedules may help to improve shift workers' eating behaviors and benefit their overall health.

Association between rotating night shift work and carotid intima-media thickness among Chinese steelworkers: a cross-sectional survey

OBJECTIVE

This study aimed to examine the association between rotating night shift work and subclinical athero-sclerosis among Chinese steelworkers.

METHODS

We evaluated 3582 steelworkers who participated in the legally required health examination in 2017. Carotid intima-media thickness (CIMT) was measured using ultrasonography. Different exposure metrics of night shifts collected by face-to-face personal interviews were used to examine the relationship between night shift work and the mean CIMT.

RESULTS

The mean CIMT values were 0.66 (standard deviation 0.22) mm in the study population. Current shift workers shown higher mean CIMT compared to day workers. There were no significant associations between the current shift status, the duration of night shifts, the cumulative number of night shifts, the average frequency of night shifts, and the mean CIMT after all confounding factors adjusted both in male and female.

CONCLUSIONS

Rotating night shift work is not associated with subclinical atherosclerosis among steelworkers. Further large-scale prospective longitudinal studies are warranted to confirm our findings.

The influence of workplace stress and coping on depressive symptoms among registered nurses in Bangladesh

Background

Nurses report high levels of workplace stress, which has been linked to an increased risk for experiencing depressive symptoms. Nurses' workplace stress is also linked to increased absenteeism and decreased job satisfaction.

Objectives

The objectives of this study were to examine: (1) the incidence of depressive symptoms among hospital-based registered nurses in Bangladesh; (2) common sources of workplace stress and their relationships to individual characteristics and depressive symptom scores; and (3) the potential mediating roles of coping strategies in the relationship between workplace stress and depressive symptoms.

Methods

A cross-sectional study design involved three hundred and fifty-two registered nurses. Data were collected using a demographic questionnaire and three standardized tools measuring sources of nurses' workplace stress, coping strategies, and depressive symptoms.

Results

More than half of the participants scored ≥ 16 on the CES-D, which was associated with a major depression episode. Total NSS scores had a small but significant influence on scores on the depression scale. Coping strategies had no mediated effect on the relationship between workplace stress and scores on the depression scale. Low-reliability coefficients for subscales of two of the standardized tools highlight the challenge for researchers in developing countries to address contextual differences that may influence the meanings attached to individual items.

Conclusion

Findings suggest that the mental health of registered nurses in Bangladesh requires immediate attention in part by attending to workplace stressors. Further research should focus on a deeper understanding of Bangladeshi registered nurses' work experiences and the unique contribution that workplace stressors have on their physical and mental health.

Association between rotating night shift work and carotid atherosclerosis among Chinese steelworkers: a cross-sectional survey

This study aimed to examine the association between rotating night shift work and carotid atherosclerosis in Chinese steelworkers. A total of 3582 subjects were included in this study. Different exposure metrics of night shifts, including current shift status, duration of night shifts (years), the cumulative number of night shifts (nights), cumulative length of night shifts (hours) and average frequency of night shifts (nights/month), were used to examine the relationship between night shift work and carotid atherosclerosis, including carotid plaque and carotid plaque scores. The prevalence of carotid plaque was 29.9% in the study population. Compared with day workers, significantly increased odds of carotid plaque were observed among shift workers in each quartile of the duration of night shifts after adjusting for potential confounders, especially in the third and fourth quartiles: odds ratio (OR) = 1.91, 95% confidence interval (CI): 1.46 to 2.49, in the third quartiles; OR = 1.69, 95% CI: 1.30 to 2.20, in the fourth quartiles. Positive associations of different exposure metrics of night shifts (continuous) with the odds of carotid plaque and the carotid plaque score were observed in the restricted cubic spline (RCS) models. No significant association was found in female workers between night shift work and carotid plaque. Rotating night shift work is associated with elevated odds of carotid atherosclerosis in male steelworkers.

Depressive symptoms in helping professions: a systematic review of prevalence rates and work-related risk factors

OBJECTIVE

The aim of this study is twofold. Our first aim is to provide an overview of the prevalence rate of depression in a wide array of helping professions. Our second aim is to identify work organization conditions that seem to be associated with this depression risk.

METHODS

Four databases were searched (CINAHL, PsycInfo, PubMed, and Web of Science) yielding 87,626 records in total. We were interested in identifying depression prevalence rates and work-related variables that have been found to contribute to depression in helping professions.

RESULTS

In total, this systematic review included 17,437 workers in more than 29 countries. Depression prevalence rate varied between 2.5% and 91.30%. The two most frequently reported professions were nurses and doctors with 73.83% and 30.84% of studies including nurses and doctors in their sample. Work factors contributing to depression included: skill utilization, decision authority, psychological demands, physical demands, number of hours worked, work schedule (irregular or regular), work schedule (daytime or night time), social support from coworkers, social support from supervisor and the family, job insecurity, recognition, job promotion, and bullying.

CONCLUSION

The results of this study highlight alarmingly high rates of depression in helping professions and should serve as a reminder to pay close attention to the mental health of those workers. Investing in employees' mental health by preventing and reducing depression risk could prove to be a valuable investment from an employer's point of view, as it is likely to increase productivity and reduce absenteeism among a host of other positive outcomes.

The association between mental health and shift work: Findings from the Atlantic PATH study

We evaluated the relationship between mental health and shift work in the Atlantic Partnership for Tomorrow's Health (PATH) cohort study. In a matched study with 12,413 participants, including 4155 shift workers and 8258 non-shift workers, we utilized general linear models and logistic regression models to assess the differences in depression, anxiety, and self-rated health. Shift workers reported higher levels of each of the mental health-related domains compared to non-shift workers. There was a significant increased risk of depression (OR = 1.13, 95% CI, 1.00-1.27) and poor self-rated health (OR = 1.13, 95% CI, 1.14-1.55) among shift workers compared to non-shift workers. Shift workers were more likely to have increased rates of depression and poor self-rated health, as well as depressive and anxiety symptom scores compared to non-shift workers. As a result, shift workers may be at increased risk of comorbidity, poor quality of life, missed work, and early retirement.

Association of Rotating Night Shift Work with Body Fat Percentage and Fat Mass Index among Female Steelworkers in North China

The aim of this study was to evaluate the associations of rotating night shift work with body fat percentage (BF%) and fat mass index (FMI). A cross-sectional study was conducted among 435 female steelworkers, aged 26-57 years in Tangshan, China. BF% was assessed via bioelectrical impedance analysis and FMI was calculated. Different exposure metrics of night shift work were used to examine the effects of night shift work on BF% and FMI. The duration (years), cumulative number (nights), and cumulative length of night shifts (hours) were positively correlated with FMI and BF%, and these relationships were independent of body mass index (BMI). Compared with day workers, night shift workers with an average frequency of night shifts >7 nights/month (odds ratio (OR) 2.50, 95% confidence interval (CI) 1.17 to 5.35) and percentage of hours on night shifts >30% (OR 2.55, 95% CI 1.21 to 5.39) had elevated odds of obesity (BF% ≥ 35.0%). Nonobese night shift workers by the BMI criterion should also be alert to the risk of the excess accumulation of body fat, which is actually responsible for most obesity-associated adverse health consequences. Health interventions for related populations need to be improved, which is currently more focused on overall weight control.

[Ethnicity and immigration status: How are they associated with work and depressive symptoms?]

BACKGROUND

The purpose of this research is to determine whether, in the Canadian workforce, cultural identity traits, particularly ethnicity and immigrant status, might modify the association of work with depressive symptoms.

METHOD

Data were derived from the nine cycles of the National Population Health Survey (NPHS) conducted by Statistics Canada. Based on a sample of 6477 workers, multilevel regression models were brought into being. Analyses were adjusted for family-related factors, non-work social support, and personal characteristics.

RESULTS

After accounting for potential confounders, ethnicity and work-related factors were distinctly and directly associated with depressive symptoms. Workers belonging to visible minorities had significantly fewer depressive symptoms than their Caucasian counterparts. Unlike Caucasians, they were more often overqualified, less in a position to use their skills, and largely without decision-making authority. On the other hand, all analyses having to do with immigrant status led to inconclusive results.

CONCLUSION

Ethnicity seems to have some bearing on the association of work with depressive symptoms among members of the Canadian workforce. It might be beneficial to carry out targeted interventions aimed at improving working conditions according to ethnicity and situations involving professional overqualification.

Are depressive disorders caused by psychosocial stressors at work? A systematic review with metaanalysis

In the last decade, many studies have examined associations between poor psychosocial work environment and depression. We aimed to assess the evidence for a causal association between psychosocial factors at work and depressive disorders. We conducted a systematic literature search from 1980 to March 2019. For all exposures other than night and shift work and long working hours, we limited our selection of studies to those with a longitudinal design. We extracted available risk estimates for each of 19 psychosocial exposures, from which we calculated summary risk estimates with 95% confidence intervals (PROSPERO, identifier CRD42019130266). 54 studies were included, addressing 19 exposures and 11 different measures of depression. Only data on depressive episodes were sufficient for evaluation. Heterogeneity of exposure definitions and ascertainment, outcome measures, risk parameterization and effect contrasts limited the validity of meta-analyses. Summary risk estimates were above unity for all but one exposure, and below 1.60 for all but another. Outcome measures were liable to high rates of false positives, control of relevant confounding was mostly inadequate, and common method bias was likely in a large proportion of studies. The combination of resulting biases is likely to have inflated observed effect estimates. When statistical uncertainties and the potential for bias and confounding are taken into account, it is not possible to conclude with confidence that any of the psychosocial exposures at work included in this review is either likely or unlikely to cause depressive episodes or recurrent depressive disorders.

Different exposure metrics of rotating night shift work and hyperhomocysteinaemia among Chinese steelworkers: a cross-sectional study

OBJECTIVE

To examine the associations of rotating night shift work with hyperhomocysteinaemia (HHcy) odds by different exposure metrics.

DESIGN

Cross-sectional study.

SETTING

Occupational physical examination centre for steel production workers, Tangshan, China.

PARTICIPANTS

A total of 6846 steelworkers, aged 22-60 years, from the baseline survey of a Chinese occupational cohort.

PRIMARY AND SECONDARY OUTCOME MEASURES

Different exposure metrics of night shift work, including current shift status, duration of night shifts (years), cumulative number of night shifts (nights), cumulative length of night shifts (hours), average frequency of night shifts (nights/month), average length of night shifts (hours/night) and percentage of hours on night shifts, were used to examine the effects of past and current night shift work on HHcy odds. The total homocysteine concentration in the plasma above 15 µmol/L was defined as HHcy.

RESULTS

Compared with those who never worked night shifts, current night shift workers had elevated odds of HHcy (OR 1.23, 95% CI 1.06 to 1.44). Considering a person's lifetime work schedule and compared with individuals who never worked night shifts, duration of night shifts >28 years (OR 1.35, 95% CI 1.12 to 1.61), average frequency of night shifts >7 nights/month (OR 1.25, 95% CI 1.07 to 1.47) and percentage of hours on night shifts >30% (OR 1.23, 95% CI 1.05 to 1.43) were associated with higher HHcy odds. The duration of night shifts >20 years and the average frequency of night shifts >7 nights/month could significantly increase the odds of HHcy regardless of whether the average length of night shifts was greater than 8 hours/night. After stratification by sex, no significant association was found in female workers between different exposure metrics of night shift work and HHcy.

CONCLUSIONS

Long duration and high frequency of night shift work are associated with higher HHcy odds among male steelworkers.

A scoping review of the nursing workforce's changing demography: Supporting Baby-Boomer nurses

AIMS

This scoping review discusses two telecommuting options to advance scholarship regarding Baby-Boomer nurses' delayed retirement and to extend their contribution to bedside nursing.

BACKGROUND

Peer-reviewed studies published in the 15 years before COVID-19 indicate that Baby-Boomer nurses' retirement will increase the global nursing shortage. However, three international trends have affected Baby-Boomer nurses' decision to delay their retirement.

EVALUATION

This review observed the scoping review framework.

KEY ISSUES

COVID-19 further disrupts the current understanding of Baby-Boomer nurses' retirement as they recognize COVID-19's impact on health care systems and younger nurses. Technological advancements and the changing needs of health care delivery have made telecommuting a practical possibility.

CONCLUSION

Baby-Boomer nurses can leverage alternative work arrangements to meet their needs and to contribute to clinical practice through telecommuting. This approach extends Baby-Boomer nurses' careers and creates a resource for bedside nurses.

IMPLICATIONS FOR NURSING MANAGEMENT

Clinical experience matters at the bedside. Telecommuting maximizes the retention of Baby-Boomer nurses' clinical expertise to benefit patients and to socialize bedside nurses. Baby-Boomer nurses can contribute to patient monitoring as well as patient education and counselling through telehealth. They can also provide asynchronous and synchronous telementoring to bedside nurses.

Prevalence and Recent Trends in Exposure to Night Shiftwork in Canada

Objectives

Night shiftwork has been linked to various health outcomes. Knowing where and to what extent workers are exposed to this type of shiftwork can help prioritize areas for intervention and further study. This study describes recent estimates of exposure to night shiftwork in Canada for 2011, and temporal trends from 1997 to 2010.

Methods

Estimates by occupation, industry, province, and sex were calculated using data from the Survey of Labour and Income Dynamics (SLID) from 1996 to 2011. Workers who reported rotating or regular night shifts were classified as exposed to shiftwork involving nights, while those reporting other types of shiftwork, outside of regular daytime and evening shifts, were classified as possibly exposed. Results, with 97.5% confidence intervals (CIs), were summarized for three exposure categories: exposed workers, possibly exposed workers, and evening shift workers. Trends in 3-year rolling averages were described.

Results

In 2011, approximately 1.8 million Canadians (97.5% CI, 1.7–1.8 million), or 12% of the working population (97.5% CI, 11–12%), were exposed to night shiftwork; 45% were female. An additional 2.6 million were possibly exposed (97.5% CI, 2.5–2.7 million workers), and 745 000 worked evening shifts (97.5% CI, 701 000–792 000). This amounts to 17% (97.5% CI, 17–18%) and 4.9% (97.5% CI, 4.6–5.2%) of the labour force, respectively. Industries with the highest prevalence were accommodation and food services (20%; 97.5% CI, 18–22%), forestry, fishing, mining, oil, and gas (19%; 97.5% CI, 16–23%), and healthcare and social assistance (18%; 97.5% CI, 17–19%). By occupation, the highest prevalence of exposure was in occupations in protective services (37%; 97.5% CI, 32–42%), professional occupations in health (35%; 97.5% CI, 32–39%), and machine operators and assemblers in manufacturing (24%; 97.5% CI, 22–28%). The overall number of exposure workers increased by 29% from 1997 to 2010, but the overall proportion remained relatively the same (11% and 12%, respectively). The proportion of female workers exposed increased by 2%.

Conclusions

These estimates characterize exposure to night shiftwork in Canada. Continued collection of shiftwork data, with greater detail on scheduling, workplace and personal factors, is needed for high-quality surveillance and investigations of shiftwork and health.

Rotating night shift work and non-alcoholic fatty liver disease among steelworkers in China: a cross-sectional survey

OBJECTIVES

In a 24/7 society, the negative metabolic effects of rotating night shift work have been increasingly explored. This study aimed to examine the association between rotating night shift work and non-alcoholic fatty liver disease (NAFLD) in steelworkers.

METHODS

A total of 6881 subjects was included in this study. Different exposure metrics of night shift work including current shift status, duration of night shifts (years), cumulative number of night shifts (nights), cumulative length of night shifts (hours), average frequency of night shifts (nights/month) and average length of night shifts (hours/night) were used to examine the relationship between night shift work and NAFLD.

RESULTS

Current night shift workers had elevated odds of NAFLD (OR, 1.23, 95% CI 1.02 to 1.48) compared with those who never worked night shifts after adjustment for potential confounders. Duration of night shifts, cumulative number of night shifts and cumulative length of night shifts were positively associated with NAFLD. Both the average frequency of night shifts (>7 nights/month vs ≤7 nights/month: OR, 1.24, 95% CI 1.06 to 1.45) and average length of night shifts (>8 hours/night vs ≤8 hours/night: OR, 1.27, 95% CI 1.08 to 1.51) were independently associated with overall NAFLD after mutually adjusting for the duration of night shifts and other potential confounders among night shift workers. No significant association was found in female workers between different exposure metrics of night shift work and NAFLD.

CONCLUSIONS

Rotating night shift work is associated with elevated odds of NAFLD in male steelworkers.

Effect of work schedule on prospective antidepressant prescriptions in Sweden: a 2-year sex-stratified analysis using national drug registry data

INTRODUCTION

Depression-related mood disorders affect millions of people worldwide and contribute to substantial morbidity and disability, yet little is known about the effects of work scheduling on depression. This study used a large Swedish survey to prospectively examine the effects of work schedule on registry-based antidepressant prescriptions in females and males over a 2-year period.

METHODS

The study was based on an approximately representative sample (n=3980 males, 4663 females) of gainfully employed participants in the Swedish Longitudinal Occupational Survey of Health. Sex-stratified analyses were conducted using logistic regression. For exposure, eight categories described work schedule in 2008: 'regular days' (three categories of night work history: none, ≤3 years, 4+ years), 'night shift work', 'regular shift work (no nights)', 'rostered work (no nights)', 'flexible/non-regulated hours' and 'other'. For the primary outcome measure, all prescriptions coded N06A according to the Anatomical Therapeutic Chemical System were obtained from the Swedish National Prescribed Drug Register and dichotomised into 'any' or 'no' prescriptions between 2008 and 2010. Estimates were adjusted for potential sociodemographic, health and work confounders, and for prior depressive symptoms.

RESULTS

In 2008, 22% of females versus 19% of males worked outside of regular daytime schedule. Registered antidepressant prescription rates in the postsurvey period were 11.4% for females versus 5.8% for males. In fully adjusted models, females in 'flexible/non-regulated' schedules showed an increased OR for prospective antidepressant prescriptions (OR=2.01, 95% CI=1.08 to 3.76). In males, odds ratios were most increased in those working 'other' schedules (OR=1.72, 95% CI=0.75 to 3.94) and 'Regular days with four or more years' history of night work' (OR=1.54, 95% CI=0.93 to 2.56).

CONCLUSIONS

This study's findings support a relationship between work schedule and prospective antidepressant prescriptions in the Swedish workforce. Future research should continue to assess sex-stratified relationships, using detailed shift work exposure categories and objective registry data where possible.

Rhythms of life: circadian disruption and brain disorders across the lifespan

Many processes in the human body - including brain function - are regulated over the 24-hour cycle, and there are strong associations between disrupted circadian rhythms (for example, sleep-wake cycles) and disorders of the CNS. Brain disorders such as autism, depression and Parkinson disease typically develop at certain stages of life, and circadian rhythms are important during each stage of life for the regulation of processes that may influence the development of these disorders. Here, we describe circadian disruptions observed in various brain disorders throughout the human lifespan and highlight emerging evidence suggesting these disruptions affect the brain. Currently, much of the evidence linking brain disorders and circadian dysfunction is correlational, and so whether and what kind of causal relationships might exist are unclear. We therefore identify remaining questions that may direct future research towards a better understanding of the links between circadian disruption and CNS disorders.