Adapting shift work schedules for sleep quality, sleep duration, and sleepiness in shift workers.

BACKGROUND: Shift work is associated with insufficient sleep, which can compromise worker alertness with ultimate effects on occupational health and safety. Adapting shift work schedules may reduce adverse occupational outcomes. OBJECTIVES: To assess the effects of shift schedule adaptation on sleep quality, sleep duration, and sleepiness among shift workers. SEARCH METHODS: We searched CENTRAL, PubMed, Embase, and eight other databases on 13 December 2020, and again on 20 April 2022, applying no language restrictions. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and non-RCTs, including controlled before-after (CBA) trials, interrupted time series, and cross-over trials. Eligible trials evaluated any of the following shift schedule components. • Permanency of shifts • Regularity of shift changes • Direction of shift rotation • Speed of rotation • Shift duration • Timing of start of shifts • Distribution of shift schedule • Time off between shifts • Split shifts • Protected sleep • Worker participation We included studies that assessed sleep quality off-shift, sleep duration off-shift, or sleepiness during shifts. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the titles and abstracts of the records recovered by the search, read through the full-text articles of potentially eligible studies, and extracted data. We assessed the risk of bias of included studies using the Cochrane risk of bias tool, with specific additional domains for non-randomised and cluster-randomised studies. For all stages, we resolved any disagreements by consulting a third review author. We presented the results by study design and combined clinically homogeneous studies in meta-analyses using random-effects models. We assessed the certainty of the evidence with GRADE. MAIN RESULTS: We included 11 studies with a total of 2125 participants. One study was conducted in a laboratory setting and was not considered for drawing conclusions on intervention effects. The included studies investigated different and often multiple changes to shift schedule, and were heterogeneous with respect to outcome measurement. Forward versus backward rotation Three CBA trials (561 participants) investigated the effects of forward rotation versus backward rotation. Only one CBA trial provided sufficient data for the quantitative analysis; it provided very low-certainty evidence that forward rotation compared with backward rotation did not affect sleep quality measured with the Basic Nordic Sleep Questionnaire (BNSQ; mean difference (MD) -0.20 points, 95% confidence interval (CI) -2.28 to 1.89; 62 participants) or sleep duration off-shift (MD -0.21 hours, 95% CI -3.29 to 2.88; 62 participants). However, there was also very low-certainty evidence that forward rotation reduced sleepiness during shifts measured with the BNSQ (MD -1.24 points, 95% CI -2.24 to -0.24; 62 participants). Faster versus slower rotation Two CBA trials and one non-randomised cross-over trial (341 participants) evaluated faster versus slower shift rotation. We were able to meta-analyse data from two studies. There was low-certainty evidence of no difference in sleep quality off-shift (standardised mean difference (SMD) -0.01, 95% CI -0.26 to 0.23) and very low-certainty evidence that faster shift rotation reduced sleep duration off-shift (SMD -0.26, 95% CI -0.51 to -0.01; 2 studies, 282 participants). The SMD for sleep duration translated to an MD of 0.38 hours' less sleep per day (95% CI -0.74 to -0.01). One study provided very low-certainty evidence that faster rotations decreased sleepiness during shifts measured with the BNSQ (MD -1.24 points, 95% CI -2.24 to -0.24; 62 participants). Limited shift duration (16 hours) versus unlimited shift duration Two RCTs (760 participants) evaluated 80-hour workweeks with maximum daily shift duration of 16 hours versus workweeks without any daily shift duration limits. There was low-certainty evidence that the 16-hour limit increased sleep duration off-shift (SMD 0.50, 95% CI 0.21 to 0.78; which translated to an MD of 0.73 hours' more sleep per day, 95% CI 0.30 to 1.13; 2 RCTs, 760 participants) and moderate-certainty evidence that the 16-hour limit reduced sleepiness during shifts, measured with the Karolinska Sleepiness Scale (SMD -0.29, 95% CI -0.44 to -0.14; which translated to an MD of 0.37 fewer points, 95% CI -0.55 to -0.17; 2 RCTs, 716 participants). Shorter versus longer shifts One RCT, one CBA trial, and one non-randomised cross-over trial (692 participants) evaluated shorter shift duration (eight to 10 hours) versus longer shift duration (two to three hours longer). There was very low-certainty evidence of no difference in sleep quality (SMD -0.23, 95% CI -0.61 to 0.15; which translated to an MD of 0.13 points lower on a scale of 1 to 5; 2 studies, 111 participants) or sleep duration off-shift (SMD 0.18, 95% CI -0.17 to 0.54; which translated to an MD of 0.26 hours' less sleep per day; 2 studies, 121 participants). The RCT and the non-randomised cross-over study found that shorter shifts reduced sleepiness during shifts, while the CBA study found no effect on sleepiness. More compressed versus more spread out shift schedules One RCT and one CBA trial (346 participants) evaluated more compressed versus more spread out shift schedules. The CBA trial provided very low-certainty evidence of no difference between the groups in sleep quality off-shift (MD 0.31 points, 95% CI -0.53 to 1.15) and sleep duration off-shift (MD 0.52 hours, 95% CI -0.52 to 1.56). AUTHORS' CONCLUSIONS: Forward and faster rotation may reduce sleepiness during shifts, and may make no difference to sleep quality, but the evidence is very uncertain. Very low-certainty evidence indicated that sleep duration off-shift decreases with faster rotation. Low-certainty evidence indicated that on-duty workweeks with shift duration limited to 16 hours increases sleep duration, with moderate-certainty evidence for minimal reductions in sleepiness. Changes in shift duration and compression of workweeks had no effect on sleep or sleepiness, but the evidence was of very low-certainty. No evidence is available for other shift schedule changes. There is a need for more high-quality studies (preferably RCTs) for all shift schedule interventions to draw conclusions on the effects of shift schedule adaptations on sleep and sleepiness in shift workers.

A scoping review of sleep education and training for nurses.

BACKGROUND: Shift work and resulting sleep impairment among nurses can increase their risk for poor health outcomes, occupational injuries, and errors due to sleep deficiencies. While sleep education and training for nurses has been recommended as part of a larger fatigue risk management system, little is known about training programs designed specifically for nurses. OBJECTIVE: Investigate the literature for current sleep education or training programs specifically for shift working nurses, with intent to assess training content, delivery characteristics, and outcome measures. DESIGN: A scoping review conducted October 2020 through September 2021. METHODS: The bibliographic databases Cumulative Index of Nursing and Allied Health (CINAHL), Scopus, PubMed, and NIOSHTIC-2 were searched using words such as "nurse," "sleep hygiene," "shift work," and "education". Studies were included if they: 1) were original research; 2) discussed sleep education, training, or sleep hygiene interventions; 3) included a study population of nurses engaging in shift work; 4) focused on sleep as a primary study measure; 5) were written in English language; and 6) were published in 2000 or later. RESULTS: Search results included 17,237 articles. After duplicates were removed, 14,620 articles were screened. Nine articles were found to meet established criteria. All studies included sleep hygiene content in the training programs, with five studies adding psychological and/or behavior change motivation training to support change in nurse sleep habits. Three studies added specific training for nurses and for managers. Delivery modes included in-person training of various lengths and frequency, mobile phone application with daily engagement, an online self-guided presentation, and daily reading material coupled with audio training. Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale were the outcome measures most frequently used. Although studies demonstrated improved sleep measures, most were pilot studies testing feasibility. CONCLUSION: Although there is a paucity of studies focused on sleep education and training for shift working nurses, we found the inclusion of sleep hygiene content was the only common characteristic of all nine studies. The variability in training content, delivery methods, and outcome measures suggests further research is needed on what constitutes effective sleep education and training for nurses.

Working hours, sleep, and fatigue in the public safety sector: A scoping review of the research.

BACKGROUND: The public safety sector includes law enforcement officers (LEO), corrections officers (CO), firefighter service (FF), wildland firefighting (WFF), and emergency medical services (EMS), as defined in the National Occupational Research Agenda (NORA) of the National Institute for Occupational Safety and Health (NIOSH). Across these occupations, shiftwork, long-duration shifts, and excessive overtime are common. Our objective was to identify research gaps related to working hours, sleep, and fatigue among these workers. METHODS: We used a scoping review study design that included searches of MEDLINE, Embase, CAB Abstracts, Global Health, PsychInfo, CINAHL, Scopus, Academic Search Complete, Agricultural and Environmental Science Collection, ProQuest Central, Cochrane Library, Safety Lit, Homeland Security Digital Library, and Sociological Abstracts using a range of occupational search terms and terms related to working hours, sleep, and fatigue. RESULTS: Out of 3415 articles returned from our database search, 202 met all inclusion criteria. Six common outcomes related to working hours, sleep, and fatigue emerged: sleep, fatigue, work performance, injury, psychosocial stress, and chronic disease. Nearly two-thirds (59%, n = 120) of the studies were observational, of which 64% (n = 77) were cross sectional and 9% were (n = 11) longitudinal; 14% (n = 30) of the studies were reviews; and 19% (n = 39) were experimental or quasi-experimental studies. Only 25 of the 202 articles described mitigation strategies or interventions. FFs, LEOs, EMS, and WFFs were the most studied, followed by COs. CONCLUSIONS: In general, more longitudinal and experimental studies are needed to enrich the knowledge base on the consequences of long working hours, poor sleep, and fatigue in the public safety sector. Few experimental studies have tested novel approaches to fatigue mitigation in diverse sectors of public safety. This gap in research limits the decisions that may be made by employers to address fatigue as a threat to public-safety worker health and safety.

Describing economic benefits and costs of nonstandard work hours: A scoping review.

BACKGROUND: The benefits of nonstandard work hours include increased production time and the number of jobs. While for some sectors, such as emergency services, around-the-clock work is a necessary and critical societal obligation, work outside of traditional daytime schedules has been associated with many occupational safety and health hazards and their associated costs. Thus, organizational- and policy-level decisions on nonstandard work hours can be difficult and are based on several factors including economic evaluation. However, there is a lack of systematic knowledge of economic benefits and costs associated with these schedules. METHODS: We conducted a scoping review of the methodology and data used to examine the economic benefits and costs of nonstandard work hours and related interventions to mitigate risks. RESULTS: Ten studies met all our inclusion criteria. Most studies used aggregation and analysis of national and other large datasets. Costs estimated include health-related expenses, productivity losses, and projections of future loss of earnings. Cost analyses of interventions were provided for an obstructive sleep apnea screening program, implementation of an employer-based educational program, and increased staffing to cover overtime hours. CONCLUSIONS: A paucity of studies assess nonstandard work hours using economic terms. Future studies are needed to expand economic evaluations beyond the employer level to include those at the societal level because impacts of nonstandard work go beyond the workplace and are important for policy analysis and formulation. We pose the opportunity for researchers and employers to share data and resources in the development of more analyses that fill these research gaps.

How effective are Fatigue Risk Management Systems (FRMS)? A review.

OBJECTIVE: Fatigue Risk Management Systems (FRMS) are a data-driven set of management practices for identifying and managing fatigue-related safety risks. This approach also considers sleep and work time, and is based on ongoing risk assessment and monitoring. This narrative review addresses the effectiveness of FRMS, as well as barriers and enablers in the implementation of FRMS. Furthermore, this review draws on the literature to provide evidence-based policy guidance regarding FRMS implementation. METHODS: Seven databases were drawn on to identify relevant peer-reviewed literature. Relevant grey literature was also reviewed based on the authors' experience in the area. In total, 2129 records were screened based on the search strategy, with 231 included in the final review. RESULTS: Few studies provide an evidence-base for the effectiveness of FRMS as a whole. However, FRMS components (e.g., bio-mathematical models, self-report measures, performance monitoring) have improved key safety and fatigue metrics. This suggests FRMS as a whole are likely to have positive safety outcomes. Key enablers of successful implementation of FRMS include organisational and worker commitment, workplace culture, and training. CONCLUSIONS: While FRMS are likely to be effective, in organisations where safety cultures are insufficiently mature and resources are less available, these systems may be challenging to implement successfully. We propose regulatory bodies consider a hybrid model of FRMS, where organisations could choose to align with tight hours of work (compliance) controls. Alternatively, where organisational flexibility is desired, a risk-based approach to fatigue management could be implemented.

Sleep disturbances and disability following work-related injury and illness: Examining longitudinal relationships across three follow-up waves.

Despite the high burden of sleep disturbances among the general population, there is limited information on prevalence and impact of poor sleep among injured workers. This study: (a) estimated the prevalence of sleep disturbance following work-related injury; and (b) examined the longitudinal association between sleep disturbances and disability/functioning, accounting for reciprocal relationships and mental illness. Longitudinal survey data were collected from workers' compensation claimants with a time-loss claim in Victoria, Australia (N = 700). Surveys were conducted at baseline, 6 months and 12 months. Sleep disturbance was measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) questionnaire. Disability/functioning was based on self-reported activity limitations, participation restrictions and emotional functioning. Path models examined the association between disability/functioning and sleep. Mean sleep disturbance T-scores were 55.2 (SD 11.4) at 6 months, with 36.4% of the sample having a T-score of 60+. Longitudinal relationships were observed between disability (specifically, emotional functioning) and sleep disturbances across successive follow-up waves. For example, each unit increase in T2 emotional functioning (five-point scale) was associated with a 1.1 unit increase in T3 sleep disturbance (approximately 29-76 scale). Cross-lagged path models found evidence of a reciprocal relationship between disability and sleep, although adjustment for mental illness attenuated the estimates to the null. In conclusion, sleep disturbances are common among workers' compensation claimants with work injuries/illnesses. Given the links between some dimensions of disability, mental health and sleep disturbances, the findings have implications for the development of interventions that target the high prevalence of sleep problems among working populations.

Working Time Society consensus statements: A multi-level approach to managing occupational sleep-related fatigue.

A substantial body of literature indicates that shift workers have a significantly higher risk of workplace accidents and injuries, compared to workers in regular daytime schedules. This can be attributed to work during nights which require workers to stay awake during normal sleeping hours and sleep during natural waking hours, leading to circadian desynchronization, sleep disruption and cognitive impairment. A fatigue-risk trajectory model developed by Dawson and McCulloch has been used to describe the series of events which may precede fatigue-related incidents. This includes insufficient sleep opportunities, impaired sleep, fatigue-behavioral symptoms, and fatigue-related errors. The purpose of this paper is to provide examples of control measures along each level of the fatigue-risk trajectory, which include: (i) work scheduling strategies to include breaks for adequate sleep opportunities; (ii) training and educational programs to help workers make best use of recovery times for quality sleep; (iii) fatigue-detection devices to alert workers and safety managers of fatigue-related behaviors and errors. A brief introduction to Fatigue-Risk Management systems is also included as a long-term sustainable strategy to maintain shift worker health and safety. The key statements in this paper represent a consensus among the Working Time Society regarding a multi-level approach to managing occupational sleep-related fatigue.

Risk of work injury among adolescent students from single and partnered parent families.

BACKGROUND: Parental involvement in keeping their children safe at work has been examined in a handful of studies, with mixed results. Evidence has suggested that non-work injury risk is higher among children from single-parent families, but little is known about their risk for work-related injuries. METHODS: Five survey cycles of the Canadian Community Health Survey were pooled to create a nationally representative sample of employed 15-19-year old students (N = 16,620). Multivariable logistic regression estimated the association between family status and work injury. RESULTS: Risk of work-related repetitive strains (OR:1.24, 95%CI: 0.69-2.22) did not differ by family type. However, children of single parents were less likely to sustain a work injury receiving immediate medical care (OR:0.43, 95%CI: 0.19-0.96). CONCLUSION: Despite advantages and disadvantages related to family types, there is no evidence that work-related injury risk among adolescents from single parent families is greater than that of partnered-parent families. Am. J. Ind. Med. 60:285-294, 2017. © 2017 Wiley Periodicals, Inc.

Mediating pathways and gender differences between shift work and subjective cognitive function.

OBJECTIVES: Increased injury risk among shift workers is often attributed to cognitive function deficits that come about as a result of sleep disruptions. However, little is known about the intermediate influences of other factors (eg, work stress, health) which may affect this relationship. In addition, gender differences in these the complex relationships have not been fully explored. The purpose of this study is to (1) identify the extent to which work and non-work factors mediate the relationship between shift work, sleep and subsequent subjective cognitive function; and (2) determine if the mediating pathways differ for men and women. METHODS: Data from the 2010 National Population Health Survey was used to create a cross-sectional sample of 4255 employed Canadians. Using path modelling, we examined the direct and indirect relationships between shift work, sleep duration, sleep quality and subjective cognitive function. Multigroup analyses tested for significantly different pathways between men and women. Potential confounding effects of age and self-reported health and potential mediating effects of work stress were simultaneously examined. RESULTS: Work stress and sleep quality significantly mediated the effects of shift work on cognition. Age and health confounded the relationship between sleep quality and subjective cognition. No differences were found between men and women. CONCLUSIONS: Occupational health and safety programmes are needed to address stress and health factors, in addition to sleep hygiene, to effectively address cognitive function among shift workers.

Health and Occupational Outcomes Among Injured, Nonstandard Shift Workers.

OBJECTIVE: This study compares health and occupational outcomes following a work-related injury for nonstandard and day-shift workers. METHODS: National Population Health Survey data were used to explore outcomes 2 years post-work injury. Retrospective-matched cohort analyses examined main effects and interactions of shift schedule and work injury with changes in health, shift schedule, and labor force status. Models were adjusted for respondent characteristics, baseline health status, and occupational strength requirements. RESULTS: Injured nonstandard shift workers reported lower health utility index scores, compared with uninjured and injured daytime workers and uninjured nonstandard-shift workers. No significant interactions between shift and injury were found with schedule change and leaving the labor force. CONCLUSIONS: Injured nonstandard-shift workers are as likely to remain employed as other groups, but may be vulnerable in terms of diminished health.

For better or worse? Changing shift schedules and the risk of work injury among men and women.

OBJECTIVES: The aim of this study was to examine the risk of work injury associated with changes in shift schedules and identify whether work injury risks differ between men and women. METHODS: Longitudinal panels from the Survey of Labor and Income Dynamics were used to describe work schedule patterns over a 6-year period among a representative sample of Canadian workers (N=19 131). Cox regression was used to estimate the risk of work injury among workers who (i) switched from regular day to nonstandard shifts, (ii) switched from nonstandard to day shifts and (iii) remained in nonstandard shifts, compared with (iv) those who worked regular day shifts only. Gender differences were examined in separate stratified analyses. Adjustments were made for potential respondent and occupational confounders. RESULTS: Increased injury risk was observed among those who: switched from day to nonstandard shifts [hazard ratio (HR) 2.60, 95% confidence interval (95% CI) 1.79-3.77], switched from nonstandard to days (HR 2.36, 95% CI 1.62-3.49), and worked nonstandard shifts only (HR 1.44, 95% CI 1.23-1.70). For women, work injury risk was higher among those who switched shifts (days to nonstandard HR 3.10, 95% CI 1.76-5.46; nonstandard to days HR 2.31, 95% CI 1.36-3.91), or worked nonstandard shifts only (HR 1.85, 95% CI 1.44-2.37) compared to day schedules. However, for men the risk of injury was elevated only among those who switched shifts (days to nonstandard HR 2.18, 95% CI 1.35-3.51; nonstandard to days HR 2.38, 95% CI 1.41-3.95). The only significant difference between men and women were among nonstandard shift workers. CONCLUSIONS: Our results suggest that changing shift types may increase work injury risk among men and women, and that the risk remains increased among women who work nonstandard shifts for a prolonged period of time. This highlights the need for awareness and implementation of health and safety programs when workers initially change shift schedules and on a regular basis to maintain worker health.

Work-injury absence and compensation among partnered and lone mothers and fathers.

BACKGROUND: The purpose of this study is to examine the risk of a work-injury absence and the likelihood of receiving compensation among partnered and lone mothers and fathers. METHODS: This study utilized data from an annual survey of Canadian residents. Logistic regression models examined the association between family status and the receipt of workers' compensation, and absences due to work-related injury or illnesses of 7 or more days. RESULTS: Being a lone mother was significantly associated with the risk of work-injury absence. Gender differences were observed for workers' compensation: mothers were half as likely as fathers to receive workers' compensation benefits, which may be attributed to differences in work experiences between men and women. CONCLUSIONS: Findings may help in understanding whether some parental situations are more vulnerable than others and may contribute to identifying policies that could help workers sustain employment or return to work following an injury.

Job strain and shift work influences on biomarkers and subclinical heart disease indicators: a pilot study.

This pilot study is one of the first to examine the impact of job strain and shift work on both the autonomic nervous system (ANS) and the hypothalamic-pituitary-adrenal (HPA) axis using two salivary stress biomarkers and two subclinical heart disease indicators. This study also tested the feasibility of a rigorous biological sampling protocol in a busy workplace setting. Paramedics (n = 21) self-collected five salivary samples over 1 rest and 2 workdays. Samples were analyzed for α-amylase and cortisol diurnal slopes and daily production. Heart rate variability (HRV) was logged over 2 workdays with the Polar RS800 Heart Rate monitors. Endothelial functioning was measured using fingertip peripheral arterial tonometry. Job strain was ascertained using a paramedic-specific survey. The effects of job strain and shift work were examined by comparing paramedic types (dispatchers vs. ambulance attendants) and shift types (daytime vs. rotating day/night). Over 90% of all expected samples were collected and fell within expected normal ranges. Workday samples were significantly different from rest day samples. Dispatchers reported higher job strain than ambulance paramedics and exhibited reduced daily alpha-amylase production, elevated daily cortisol production, and reduced endothelial function. In comparison with daytime-only workers, rotating shift workers reported higher job strain, exhibited flatter α-amylase and cortisol diurnal slopes, reduced daily α-amylase production, elevated daily cortisol production, and reduced HRV and endothelial functioning. Despite non-statistically significant differences between group comparisons, the consistency of the overall trend in subjective and objective measures suggests that exposure to work stressors may lead to dysregulation in neuroendocrine activity and, over the long-term, to early signs of heart disease. Results suggest that further study is warranted in this population. Power calculations based on effect sizes in the shift type comparison suggest a study size of n = 250 may result in significant differences at p = 0.05. High compliance among paramedics to complete the intensive protocol suggests this study will be feasible in a larger population.

Shift work trends and risk of work injury among Canadian workers.

OBJECTIVE: The aim of this study was to examine the risk of work injury across shift work types in a -representative sample of Canadian workers. METHODS: We used the Survey of Labour and Income Dynamics to investigate trends in work injury by shift type between 1996-2006. Work injury was defined by receipt of workers' compensation. Logistic regression was used to estimate the risk between shift type and worker injury after adjusting for potential confounders. RESULTS: The rate of work injury decreased overall between 1996-2006, but did not decline for night shift -workers. Night shift work was associated with work injury for women [odds ratio (OR) 2.04, 95% confidence interval (95% CI) 1.13-3.69] and men (OR 1.91, 95% CI 1.21-3.03), while rotating shift work was associated with work injury for women (OR 2.29, 95% CI 1.37-3.82). The excess risk of work injury attributed to shift work was 14.4% for women and 8.2% for men based on population attributable fraction estimates. CONCLUSIONS: Rotating and night shift workers appear to have a higher risk of work injury, particularly among women. Regulatory agencies and employers need to identify and mitigate factors that give rise to increased work injury among these types of shift workers.