Night shift work, chemical coexposures and risk of female breast cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort: a prospectively recruited case-cohort study

OBJECTIVES

This study examined the association between night shift work and risk of breast cancer, overall and by hormone receptor subtype, among females in the Norwegian Offshore Petroleum Workers (NOPW) cohort. We also examined the association of coexposure (chlorinated degreasers and benzene) and breast cancer risk, and possible interaction with work schedule.

DESIGN

Prospectively recruited case-cohort study within the NOPW cohort.

SETTING

Female offshore petroleum workers active on the Norwegian continental shelf.

PARTICIPANTS

600 female workers (86 cases and 514 non-cases) were included in the study. We excluded workers that died or emigrated before start of follow-up, had missing work history, were diagnosed with breast cancer or other prior malignancy (except non-melanoma skin cancer) before start of follow-up.

RESULTS

No overall association was found between breast cancer risk and work schedule (HR 0.87, 95% CI 0.52 to 1.46 for work schedule involving night shift vs day shift only). There was no significant association between work schedule and risk of any breast cancer subtype. No significant interactions were found between work schedule and chemical coexposures (breast cancer overall P_{interaction chlorinated degreasers}=0.725 and P_{interaction benzene}=0.175).

CONCLUSIONS

Our results did not provide supporting evidence that work schedule involving night shift affects breast cancer risk in female offshore petroleum workers, but should be considered cautiously due to few cases. Further studies with larger sample sizes are warranted.

Shift and night work during pregnancy and preterm birth-a cohort study of Swedish health care employees

BACKGROUND

Previous studies of preterm birth (PTB) concerning night work have been inconclusive and partly limited by imprecise data on working schedules. This study investigated the risk of PTB in relation to detailed, registry-based data on working hours.

METHODS

In a register-based prospective cohort study, we identified 4970 singleton births with information on PTB from the Swedish Medical Birth Register of health care employees in Stockholm. Day-by-day information on working hours 2008-16 was obtained from a computerized employee register. Odds ratios (ORs) of PTB according to work hour characteristics were analysed by logistic regression adjusted for mother's age, stature, body mass index (BMI), parity, smoking habits, education, profession and country of birth.

RESULTS

There was an increased risk of PTB among those who frequently worked night shifts (>25 times) [OR, 1.62; 95% confidence interval (CI), 1.03-2.53] and who ever worked ≥3 consecutive night shifts (OR, 1.43; 95% CI, 1.03-1.99) during the first trimester. Frequently (> 8 times) working 3 or more consecutive nights, and frequently (>18 times) having quick returns from night shifts (<28 h) during the first trimester showed 3-4 fold increased risk of PTB. Moreover, working frequent (>20 times) long shifts (≥10 h) (OR 1.63; 95% CI, 1.07-2.49) during the first trimester and working any Week >40 h (OR 2.05; 95% CI, 1.31-3.22) during the third trimester were associated with PTB.

CONCLUSIONS

In this cohort of Swedish health care employees with registry-based data on working hours, night work, especially working frequent consecutive nights, and quick returns from night shifts during the first trimester were associated with increased risk of PTB among pregnant women.

Effects of a modified shift work organization and traffic load on air traffic controllers' sleep and alertness during work and non-work activities

A 'compressed' shift schedule (substitution of a rest day by a shift, shortening the duration of work breaks) was introduced for a better fit with aircraft traffic load. Thereafter, the company asked for a survey assessing the effects of the compressed shift system. Air traffic controllers (ATCOs) completed retrospectively a specific questionnaire assessing the effects of shift schedule (modified vs. initial) and of traffic load on fatigue, alertness (on-shift, upon awakening, during daily non-work activities), and sleep (duration, satisfaction). Work organization had marginal and unexpected effects, which might indicate ATCOs' disapproval of the intervention. Traffic load affected sleep satisfaction and alertness during work and non-work activities. Specific effects of shift included reduced sleep time prior to morning shifts compared to night shifts, whereas alertness and fatigue were rated at comparable levels for both shifts. Results suggest that shiftwork features which favor sleep loss across a work cycle have deleterious consequences on alertness and increase the need for recovery, which are further enhanced by traffic load.

Predictive Biomathematical Modeling Compared to Objective Sleep During COVID-19 Humanitarian Flights

BACKGROUND: Biomathematical modeling software like the Sleep, Activity, Fatigue, and Task Effectiveness (SAFTE) model and Fatigue Avoidance Scheduling Tool (FAST) help carriers predict fatigue risk for planned rosters. The ability of a biomathematical model to accurately estimate fatigue risk during unprecedented operations, such as COVID-19 humanitarian ultra-long-range flights, is unknown. Azul Cargo Express organized and conducted five separate humanitarian missions to China between May and July 2020. Prior to conducting the missions, a sleep-prediction algorithm (AutoSleep) within SAFTE-FAST was used to predict in-flight sleep duration and pilot effectiveness. Here we compare AutoSleep predictions against pilots' sleep diary and a sleep-tracking actigraphy device (Zulu watch, Institutes for Behavior Resources) from Azul's COVID-19 humanitarian missions.METHODS: Pilots wore Zulu watches throughout the mission period and reported sleep duration for their in-flight rest periods using a sleep diary. Agreement between AutoSleep, diary, and Zulu watch measures was compared using intraclass correlation coefficients (ICC). Goodness-of-fit between predicted effectiveness distribution between scenarios was evaluated using the R² statistic.RESULTS: A total of 20 (N = 20) pilots flying across 5 humanitarian missions provided sleep diary and actigraphy data. ICC and R² values were >0.90, indicating excellent agreement between sleep measures and predicted effectiveness distribution, respectively.DISCUSSION: Biomathematical predictions of in-flight sleep during unprecedented humanitarian missions were in agreement with actual sleep patterns during flights. These findings indicate that biomathematical models may retain accuracy even under extreme circumstances. Pilots may overestimate the amount of sleep that they receive during extreme flight-duty periods, which could constitute a fatigue risk.Devine JK, Garcia CR, Simoes AS, Guelere MR, de Godoy B, Silva DS, Pacheco PC, Choynowski J, Hursh SR. Predictive biomathematical modeling compared to objective sleep during COVID-19 humanitarian flights. Aerosp Med Hum Perform. 2022; 93(1):4-12.

Sleep quality, personal and work variables and life habits of hospital nurses

OBJECTIVE

to identify the possible associations between sleep quality, personal and work variables and the life habits of hospital nurses.

METHOD

a cross-sectional, exploratory, correlational and quantitative study, carried out from October to December 2019. The data were collected with the application of a questionnaire that addressed the respondents' personal characteristics, life habits and working conditions. The Pittsburgh Sleep Quality Index (PSQI), Brazilian Portuguese version, was used to assess sleep quality.

RESULTS

the participants were 42 professionals: 31 (73.8%) women, aged between 26 and 66 years old (mean of 40.2); 61.9% worked overtime; 26.2% had two employment contracts and 40.5% had absences from work. Sleep quality was considered good by 9.5% of the participants, poor by 64.3% and categorized as with sleep disorders by 26.2%. In the population that worked rotating shifts, this quality was identified as poor by 26.2%. The worst results were found in the age group from 30 to 39 years old and there was a statistical significance in the "living with a partner" variable.

CONCLUSION

there was impairment in the nurses' sleep quality and there is a need to monitor these workers, particularly those who work in shifts, in order to provide preventive measures to mitigate the harms to their health.

Rotating night shift work, sleep duration and elevated gamma-glutamyl transpeptidase among steelworkers: cross-sectional analyses from a Chinese occupational cohort

OBJECTIVES

This study aimed to evaluate the separate and combined effects of rotating night shift work and lifestyle factors with elevated gamma-glutamyl transpeptidase (GGT) among steelworkers.

DESIGN, SETTING AND PARTICIPANTS

This cross-sectional study used the baseline information from a Chinese occupational cohort. The in-service workers of the production department of Tangsteel Company who participated in the occupational health examination in Tangshan from February to June 2017 were selected as the research objects.

MAIN OUTCOME MEASURES

The separate and combined effects of rotating night shift work and lifestyle factors with elevated GGT among steelworkers.

RESULTS

The information of 7031 subjects from the production department of Tangsteel Company was analysed. Results showed that the current shift workers and the workers with the duration of night shifts>19 years, the cumulative number of night shifts>1774 nights, the average frequency of night shifts≤7 nights/month and the average frequency of night shifts>7 nights/month had elevated odds of elevated GGT, compared with those who never worked night shifts, and ORs, (95% CIs) were 1.39, (1.10 to 1.75), 1.46, (1.15 to 1.86), 1.46, (1.15 to 1.85), 1.34, (1.04 to 1.73) and 1.37, (1.09 to 1.74) after adjustment for potential confounders. The independent effect of shorter sleep duration (<7 hours/day) on elevated GGT was not statistically significant. Among workers who had shorter sleep duration, the association between rotating night shift work and elevated GGT was statistically significant, but no associations were found among workers with the sleep duration of ≥7 hours/day. In addition, other lifestyle factors affected the association between rotating night shift work and elevated GGT.

CONCLUSIONS

Rotating night shift work is associated with elevated GGT among steelworkers. In particular, the effect of rotating night shift work on elevated GGT was affected by sleep duration and other lifestyle factors.

Objective Assessment of Sleep Patterns among Night-Shift Workers: A Scoping Review

In this scoping review of the literature, we identified the types and the parameters of objective measurements to assess sleep patterns among night-shift workers. We conducted a literature search using electronic databases for studies published from 1991 to 2020 and charted and summarized key information. We included 32 studies in the review. Polysomnography was used in 6 studies and wearable sleep detection devices were utilized in 26 studies. The duration of sleep assessment using the wearable devices ranged from 1 day to ≥4 weeks, and more than half of the studies collected data for >2 weeks. The majority of the studies used subjective questionnaires, such as the Karolinska Sleepiness Scale, Epworth Sleepiness Scale, and Pittsburgh Sleep Quality Index, in addition to objective sleep measurements. Total sleep time was the most common parameter, followed by sleep efficiency, sleep onset latency, and time or frequency of being awake. As the utilization of wearable devices to assess the sleep patterns of night-shift workers is expected to increase, further evaluation of device accuracy and precision, optimal data collection period, and key parameters is warranted.

Effect of occupation on sleep duration among daytime Japanese workers: A cross-sectional study

Occupation is one of the factors contributing to the loss of sleep. Although many studies have investigated sleep loss due to irregular and nighttime shifts, the causes of sleep loss in daytime workers remain unknown. The aims of the present study were to determine whether occupation is a dependent factor for sleep duration and whether working status and lifestyle are related to sleep duration.We examined the health check results of 17,519 (9028 men and 8491 women) workers who had at least 1 health check between the fiscal years 2013 and 2019. We asked about the workers' occupation, bedtime, dinner time, overtime work, and commuting time, using a self-administered questionnaire at their health check. The occupations were classified into 4 categories: high white-collar, low white-collar, pink-collar, and blue-collar. We conducted a linear regression model and analysis of covariance to investigate the effect of occupation on sleep duration.As a result of linear regression analysis, bedtime, overtime work and occupation were significantly associated with decreased sleep duration in males, and bedtime, age, and occupation were significantly associated with decreased sleep duration in females. Analysis of covariance revealed that both male and female blue-collar tended to sleep for significantly shorter durations than those in the other occupations.The results of the current study indicate that sleep duration is affected by occupation. When determining the cause of loss of sleep, medical personnel should consider their patient's lifestyles and how they have been affected by their occupation.

Association between glycemic control and shift working among healthcare workers with diabetes, Dammam, Saudi Arabia: Five years' experience

OBJECTIVES

To delineate the relation between shift work and glycemic control among the healthcare workers (HCWs) with diabetes mellitus (DM) in the hospitals of Dammam, Saudi Arabia.

METHODS

A cross-sectional study was conducted among HCWs with DM working in 3 hospitals in Dammam, Saudi Arabia, from November 2018 to January 2019. The study participants answered a self-administered questionnaire related to sociodemographic data, work-related questions, diabetes-related questions, the latest hemoglobin A1C test outcome, and self-management activities. The Chi-square and t-test were used to determine the association between the risk factor of glycemic control and shift work.

RESULTS

The HCW's ages ranged from 24-60 years. The mean age of the employees in the day shift was 42.4±7.7 years and night shift was 42.1±7.3 years. The significant difference between daytime workers and shift workers was observed in terms of occupation, and obesity. Day shift employees reported being significantly more physically active than shift workers. The daily day shift led the employee to miss their routine clinic visits for DM. Shift workers had more weight gain due to unhealthy food intake, sleep deprivation, and improper physical activity when compared with daytime employees. Anti-clockwise shift rotation significantly demonstrated that 92.9% of employees developed uncontrolled DM.

CONCLUSION

Glycemic control was worsened among the shift worker with DM compared to daytime workers.

Association of Night Shift Work With Chronic Spontaneous Urticaria and Effect Modification by Circadian Dysfunction Among Workers

Purpose: Night shift work is common in the current working environment and is a risk factor for many diseases. The study aimed to explore the relationship between night shift work with chronic spontaneous urticaria (CSU), and the modification effect of circadian dysfunction on it. Methods: A cross-sectional survey was conducted among Chinese workers. Exposure was measured by night work history and duration. Circadian dysfunction was characterized by excessive daytime sleepiness (EDS). The diagnosis of CSU was made by dermatologists who were investigating on the spot. The effect size was expressed as odds ratios (ORs). Results: A total of 8,057 participants were recruited, and 7,411 (92%) with complete information were included in the final analyses. The prevalence rates of CSU for workers without night shift and those with night shift history were 0.73 and 1.28%, respectively. Compared with workers who never worked night shifts, the risk of CSU increased with the length of night shift work: OR = 1.55 (95% confidence interval [CI]: 0.78-3.06) for duration <5 years and OR = 1.91 (95% CI: 1.12-3.26) for duration ≥5 years. EDS s EDS has been shown to modify this combination. Among workers without EDS, there was no association between night shift and CSU (OR = 0.94; 95% CI: 0.49-1.79). Whereas, in participants with EDS, the correlation was significant (OR = 3.58; 95% CI: 1.14-11.20). However, the effect modification by sleep disturbance was not observed. Conclusions: Night shift work is a risk factor for CSU, and there is a dose-response relationship between night shift work hours and the risk of CSU. This connection may be modified by circadian dysfunction.

Sleep Disorders Among Commercial Airline Pilots

BACKGROUND: Over the next 20 yr, international market expansion will necessitate the production of new commercial airplanes and the recruitment of additional crewmembers and technicians. Research has proven that fatigue and lack of sleep are risk factors for impaired cognitive performance and human error. Pilots frequently report fatigue to their employers, which may be related to sleep disturbance. Airline pilots, in particular, often experience circadian desynchronization and other types of sleep disorders. Shift workers have been observed to be at higher risk of fatigue that affects their performance and alertness. In Saudi Arabia, sleep disorders among airline pilots are understudied and underreported. The primary objective of this study was to screen for and determine the risk of sleep disorders, fatigue, and depression among pilots.METHODS: A cross-sectional epidemiological study with national commercial pilots was conducted from March 2019 to March 2020 using validated questionnaires to screen for the risk of sleep disorders, fatigue, and depression.RESULTS: In total, 344 pilots participated in the study. Half the sample was at risk for insomnia and fatigue. Older and more experienced pilots were less likely to suffer impaired sleep quality, insomnia, sleepiness, fatigue, and depression. In total, 59 (17.2%) pilots were at high risk for sleep apnea.CONCLUSION: The current study found that pilots were at risk of developing sleep disorders. A more robust and objective assessment is warranted for screening.Alzehairi A, Alhejaili F, Wali S, Al Qassas I, Balkhyour M, Pandi-Perumal SR. Sleep disorders among commercial airline pilots. Aerosp Med Hum Perform. 2021; 92(12):937-944.

[Workplace Fatigue, Metabolic Syndrome, and Cardiovascular Disease Risks: A Study of Long-Term Night Shift Nurses]

BACKGROUND

Night-shift work affects the physical and mental health of employees. Early identification of relevant high-risk groups may be referenced in health promotion, job analysis, and job design.

PURPOSE

To explore the differences in workplace fatigue, physiological index of metabolic syndrome, and risk of cardiovascular disease between long-term and non-long-term night-time working nursing staff.

METHODS

The health examination data of 91 long-term and 119 non-long-term night-shift nurses were collected. A sub-data analysis approach was used and t-test, chi-square, Pearson`s correlation, and hierarchical multiple regression were used to conduct statistical analysis.

RESULTS

A positive correlation between cardiovascular risk and workplace fatigue was found in the long-term night-shift working group. Moreover, a lower average duration of sleep was found in the non-long-term night-shift working group. Finally, the participants with workplace fatigue and metabolic syndrome were found to have higher levels of cardiovascular risk.

CONCLUSIONS / IMPLICATIONS FOR PRACTICE

Nursing staff who work night shifts for long-term and non-long-term periods should all receive regular health check-ups and practice healthy eating, exercise, and sleep habits. Employers should provide regular health checkups to their nursing staff and implement measures to identify health hazards in accordance with laws on labor standards, occupational safety, and health and labor health protection regulations, and then adopt appropriate plans and necessary safety and health measures to achieve a mutually beneficial result for both employers and employees in the healthcare industry.

Effects of 2-hour nighttime nap on melatonin concentration and alertness during 12-hour simulated night work

A nighttime nap is expected to mitigate melatonin suppression during night work by blocking light input to the retina, but it is unclear. In the present study, we investigated the effects of a nap break on melatonin level, subjective sleepiness, and vigilance performance during simulated night work. Eleven healthy young males (mean ± SD age: 22.2 ± 4.1 years) participated in counterbalanced crossover design experiments with two conditions (nap vs. no nap). The subjects performed 12-hour simulated night work from 21:00 to 09:00 h (illuminance: ~500 lx). Subjects with a nap condition took a nap for 2 hours in a dark room from 03:00, while subjects with a no nap condition continued the simulated night work. The results showed that immediately after the 2-h nap break, the melatonin level at 05:00 h temporarily recovered from light-induced melatonin suppression during the simulated night work but significantly suppressed again at 07:00 and 09:00 h. Subjective alertness and vigilance performance were impaired immediately after the nap break but subsequently enhanced. The results suggest that a single nap break for 2 hours could be a strategy to enhance alertness during the last part of night shift but inadequate for mitigating melatonin suppression.

Content Validation of a Chrononutrition Questionnaire for the General and Shift Work Populations: A Delphi Study

Unusual meal timing has been associated with a higher prevalence of chronic disease. Those at greater risk include shift workers and evening chronotypes. This study aimed to validate the content of a Chrononutrition Questionnaire for shift and non-shift workers to identify temporal patterns of eating in relation to chronotype. Content validity was determined using a Delphi study of three rounds. Experts rated the relevance of, and provided feedback on, 46 items across seven outcomes: meal regularity, times of first eating occasion, last eating occasion, largest meal, main meals/snacks, wake, and sleep, which were edited in response. Items with greater than 70% consensus of relevance were accepted. Rounds one, two, and three had 28, 26, and 24 experts, respectively. Across three rounds, no outcomes were irrelevant, but seven were merged into three for ease of usage, and two sections were added for experts to rate and comment on. In the final round, all but one of 29 items achieved greater than 70% consensus of relevance with no further changes. The Chrononutrition Questionnaire was deemed relevant to experts in circadian biology and chrononutrition, and could represent a convenient tool to assess temporal patterns of eating in relation to chronotype in future studies.

Night Shift and Decreased Brain Activity of ICU Nurses: A Near-Infrared Spectroscopy Study

Background: Shift working is associated with a profound desynchronization of circadian rhythm and in particular, night-shift work disrupts normal circadian physiology. Sleep deprivation affects the functioning of certain brain areas and thus impairs cognitive performance. The purpose of this study was to investigate the effects of the night shift on cognitive performance and cerebral oxygenation/haemodynamics. Methods: A prospective, observational, comparative, randomized and cross-over study was carried out. A total of 74 intensive care unit nurses in Spain were included in the study. The following variables were measured: sociodemographic, burnout, anxiety, baseline cerebral oxygenation levels on night and day shift using a near-infrared spectroscopy system and cognitive task performance during a verbal fluency task to evaluate the alterations in the prefrontal cortex, assessed as changes in regional saturation index. Results: The average regional saturation index decreased significantly in the night shift (r = 0.560, p < 0.001). The ICU nurses showed a significant decrease in the verbal fluency test on average (8.53 ± 8.49, p < 0.001) and, in general, there was also a significant increase in anxiety score (3.17 ± 7.56, p = 0.001). Conclusions: Sleep deprivation during the night shift was considered to be related to decreased dorsolateral PFC reactivity. After the night shift, the nurses showed a decrease in prefrontal cortex activity and in cognitive performance.

Guiding principles for determining work shift duration and addressing the effects of work shift duration on performance, safety, and health: guidance from the American Academy of Sleep Medicine and the Sleep Research Society

CITATION

Risks associated with fatigue that accumulates during work shifts have historically been managed through working time arrangements that specify fixed maximum durations of work shifts and minimum durations of time off. By themselves, such arrangements are not sufficient to curb risks to performance, safety, and health caused by misalignment between work schedules and the biological regulation of waking alertness and sleep. Science-based approaches for determining shift duration and mitigating associated risks, while addressing operational needs, require: (1) a recognition of the factors contributing to fatigue and fatigue-related risks; (2) an understanding of evidence-based countermeasures that may reduce fatigue and/or fatigue-related risks; and (3) an informed approach to selecting workplace-specific strategies for managing work hours. We propose a series of guiding principles to assist stakeholders with designing a shift duration decision-making process that effectively balances the need to meet operational demands with the need to manage fatigue-related risks.

Estimation of Surgical Resident Duty Hours and Workload in Real Time Using Electronic Health Record Data

OBJECTIVE

To explore the use of electronic health record (EHR) data to estimate surgery resident duty hours and monitor real time workload.

DESIGN

Retrospective analysis of resident duty hours logged using a voluntary global positioning system (GPS)-based smartphone application compared to duty hour estimates by an EHR-based algorithm. The algorithm estimated duty hours using EHR activity data and operating room logs. A dashboard was developed through Plan-Do-Study-Act cycles for real-time monitoring of workload.

SETTING

Single tertiary/quaternary medical center general surgery residency program with approximately 90 categorical, preliminary, and integrated residents at eight clinical sites.

PARTICIPANTS

Categorical, preliminary, and integrated surgery residents of all clinical years who volunteered to pilot a GPS application to track duty hours.

RESULTS

Of 2,623 work periods by 59 residents were logged with both methods. EHR-estimated work periods started later than GPS logs (median 0.3 hours, interquartile range [IQR] -0.1 - 0.3); EHR-estimated work periods ended earlier than GPS logs (median 0.1 hours, IQR -0.7 - 0.3); and EHR-estimated duty hour totals were less than totals logged by GPS (median -0.3 hours, IQR -0.8 - +0.1). Overall correlation between weekly duty hours logged by EHR and GPS was 0.79. Correlations between the 2 systems stratified from PGY-1 through PGY-5 were 0.76, 0.64, 0.82, 0.87, and 0.83, respectively. The algorithm identified six 80-hour workweek violations (averaged over 4 weeks), while GPS logs identified 8. EHR-based duty hours and operational data were integrated into a dashboard to enable real time monitoring of resident workloads.

CONCLUSIONS

EHR-based estimation of surgical resident duty hours has good correlation with GPS-based assessment of duty hours and identifies most workweek duty hour violations. This approach allows for dynamic workload monitoring and may be combined with operational data to anticipate and prevent duty hour violations, thereby optimizing learning.

Comparison of Operative Experiences of PGY-1 and PGY-2 General Surgery Residents During Night-Float vs. 24-Hour Call Systems

OBJECTIVE

We aimed to specifically compare the impact of a night-float system vs. a 24-hour call system on the number and types of cases performed by PGY-1 and PGY-2 general surgery residents to determine if both of these schedules could meet the ACGME first two-year 250 case minimum requirement, and if so, which schedule provided the best operative experience for PGY-1 and PGY-2 residents.

DESIGN

This is a retrospective review of call schedules and operative case logs of PGY-1 and PGY-2 general surgery residents. Residents were separated into two groups based on type of call schedule: 24-hour vs. night-float. The case logs of PGY-1 and PGY-2 residents were obtained from the ACGME Case Log System and data analysis was performed between the two groups.

SETTING

This study was performed at a general surgery residency at a hybrid academic center.

PARTICIPANTS

Forty-three residents met inclusion criteria. Twenty-three were part of the night-float system and 20 were part of the 24-hour call system.

RESULTS

Total cases and major cases for PGY-1 and PGY-2 years were compared between the two groups. The 24-hour call group had a significantly higher total number of cases than the night-float group (646.0 ± 181.5 vs. 504.8 ±148.9, p = 0.008). Major cases were also significantly higher in the 24-hour call group than the night-float group (418.5 ± 99.6 vs. 355 ± 99.5, p = 0.043).

CONCLUSIONS

Both the 24-hour call and night-float systems were able to meet the ACGME first two year 250 case minimum requirement as well as follow work-hour guidelines. The 24-hour call system was associated with PGY-1 and PGY-2 residents having a better operative experience than the night-float system.

ACGME 2011 Duty Hours Restrictions and Their Effects on Surgical Residency Training and Patients Outcomes: A Systematic Review

OBJECTIVE

The ACGME instituted the 2011 residency duty-hour restrictions (DHR) to increase resident well-being and patient safety. However, its eventual remodeling came after patient care was deemed unaffected. We aimed to identify the effects of the ACGME 2011-DHR on (1) patient outcomes, (2) surgical resident case volume, and (3) surgical resident quality of life.

DESIGN

Literature search using Google Scholar, PubMed, Cochrane, and Embase for publications between 2010 and 2020, on the 2011-DHR effects on resident and patient outcomes. Studies containing the number of cases performed during training, quality of life, and surgical patients' outcomes were included.

RESULTS

Fifteen studies met inclusion criteria. There was no difference in complication rates for surgical patients post 2011-DHR (p = 0.561). 2011-DHR caused surgical caseload shifts from interns to senior residents reflected by decreased operative cases for interns (p = 0.005) with significantly more total cases performed by chief residents (p = 0.0006). Pre-2011-DHR had more work flexibility that led to higher resident well-being (p = 0.01). Only 25% of residents approved of the 2011-DHR while 87% felt these restrictions would have adverse effects.

CONCLUSION

Current literature supports that the 2011-DHR did not improve patient outcomes, decreased surgical experience for junior residents and shifted clinical responsibilities to senior residents. System wide regulations such as the 2011-DHR may unintentionally create professional and personal life imbalance and introduce stress over resident inability to perform clinical responsibilities. Future systemic interventions to address resident well-being should be made with caution and not solely limited to the number of hours they work in a single week or in a single shift.

An investigation of the effects of different shift schedules on the fatigue and sleepiness of officers on oil tankers during cargo handling operations

Cargo handling is an operation, which requires a high level of performance from the officer of the watch (OOW). This study aimed to investigate the effect of different shift schedules on sleep quality, cognitive performance, and sleepiness of 139 OOWs on oil tankers with 4on-8off shifts, during the first shift of cargo handling. Sleep quality (Pittsburgh Sleep Quality Index (PSQI)), level of sleepiness (the Karolinska Sleepiness Scale (KSS)), Psychomotor Vigilance Task (PVT), and Arrow Flanker task performance were examined. The results showed that OOWs with (00:00-04:00, 12:00-16:00) and (04:00-08:00, 16:00-20:00) shifts had impaired cognitive performance and higher sleepiness during the cargo handling operation, and they also experienced impaired sleep quality. The results demonstrated that the circadian rhythm and homeostatic sleep drive have a greater impact on cognitive performance and sleepiness than time on shifts. These results suggest that allocating rest hours immediately before the cargo handling operation may reduce the risk of fatigue. Practitioner Summary: To the best of our knowledge, this maritime field study shows for the first time the prevalence of seafarers' sleepiness and cognitive performance while on duty during cargo handling, using a pre-post shift comparison between three different shifts. The results show the negative effects of keeping watch at night on sleep quality, sleepiness, and the impaired cognitive performance both in the day and the night shifts.

Biomathematical Modeling Predicts Fatigue Risk in General Surgery Residents

OBJECTIVE

To assess resident fatigue risk using objective and predicted sleep data in a biomathematical model of fatigue.

DESIGN

8-weeks of sleep data and shift schedules from 2019 for 24 surgical residents were assessed with a biomathematical model to predict performance ("effectiveness").

SETTING

Greater Washington, DC area hospitals RESULTS: As shift lengths increased, effectiveness scores decreased and the time spent below criterion increased. Additionally, 11.13% of time on shift was below the effectiveness criterion and 42.7% of shifts carried excess sleep debt. Sleep prediction was similar to actual sleep, and both predicted similar performance (p ≤ 0.001).

CONCLUSIONS

Surgical resident sleep and shift patterns may create fatigue risk. Biomathematical modeling can aid the prediction of resident sleep patterns and performance. This approach provides an important tool to help educators in creating work-schedules that minimize fatigue risk.

Improving health and economic security by reducing work schedule uncertainty

Work schedules in the service sector are routinely unstable and unpredictable, and this unpredictability may have harmful effects on health and economic insecurity. However, because schedule unpredictability often coincides with low wages and other dimensions of poor job quality, the causal effects of unpredictable work schedules are uncertain. Seattle's Secure Scheduling ordinance, enacted in 2017, mandated greater schedule predictability, providing an opportunity to examine the causal relationship between work scheduling and worker health and economic security. We draw on pre- and postintervention survey data from workers in Seattle and comparison cities to estimate the impacts of this law using a difference-in-differences approach. We find that the law had positive impacts on workers' schedule predictability and stability and led to increases in workers' subjective well-being, sleep quality, and economic security. Using the Seattle law as an instrumental variable, we also estimate causal effects of schedule predictability on well-being outcomes. We show that uncertainty about work time has a substantial effect on workers' well-being, particularly their sleep quality and economic security.

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.

Working hours - tracking the current and future trends

It is important to track the trends of future working hours, since working hours have strong associations to everyday life and work-life interaction, but also to health. In this paper we aim to track the current and future trends in working hours. We discuss the trends through the key dimensions of working hours: the length, timing, tempo and autonomy. We also consider the role of current trends of spatial changes of work. Changes in working time patterns are fostered by several driving factors: globalization and business restructuring challenging the current work organizations, new information technologies, demographic and climate change and the current and future pandemics. The past and current tremendous changes in working hours indicate that changes in working hours will continue. The contemporary trends in future working hours pose risks for personal, family and social life, material well-being and health. At its best, however, the new post-industrial working time regime may provide more autonomy and time for recovery to employees as new technologies and changes in business structures release opportunities for greater individual autonomy over how, where, and for how long paid work is performed.

Sleep and Alertness Among Interns in Intensive Care Compared to General Medicine Rotations: A Secondary Analysis of the iCOMPARE Trial

BACKGROUND

Medical interns are at risk for sleep deprivation from long and often rotating work schedules. However, the effects of specific rotations on sleep are less clear.

OBJECTIVE

To examine differences in sleep duration and alertness among internal medicine interns during inpatient intensive care unit (ICU) compared to general medicine (GM) rotations.

METHODS

This secondary analysis compared interns during a GM or ICU rotation from a randomized trial (2015-2016) of 12 internal medicine residency programs assigned to different work hour limit policies (standard 16-hour shifts or no shift-length limits). The primary outcome was sleep duration/24-hour using continuous wrist actigraphy over a 13-day period. Secondary outcomes assessed each morning during the concomitant actigraphy period were sleepiness (Karolinska Sleepiness Scale [KSS]), alertness (number of Brief Psychomotor Vigilance Test [PVT-B] lapses), and self-report of excessive sleepiness over past 24 hours. Linear mixed-effect models with random program intercept determined associations between each outcome by rotation, controlling for age, sex, and work hour policy followed.

RESULTS

Of 398 interns, 386 were included (n = 261 GM, n = 125 ICU). Average sleep duration was 7.00±0.08h and 6.84±0.10h, and number of PVT lapses were 5.5±0.5 and 5.7±0.7 for GM and ICU, respectively (all P > .05). KSS was 4.8±0.1 for both rotations. Compared to GM, ICU interns reported more days of excessive sleepiness from 12am-6am (2.6 vs 1.7, P < .001) and 6am-12pm (2.6 vs 1.9, P = .013) and had higher percent of days with sleep duration < 6 hours (27.6% vs 23.4%, P < .001). GM interns reported more days with no excessive sleepiness (5.3 vs 3.7, P < .001).

CONCLUSIONS

Despite ICU interns reporting more excessive sleepiness in morning hours and more days of insufficient sleep (<6 hours), overall sleep duration and alertness did not significantly differ between rotations.

Mitigating Drowsy Driving Risk for Night Shift Nurses

Preventive measures range from napping to installing driver monitoring systems in cars.

Short and Long Haul Pilots Rosters, Stress, Sleep Problems, Fatigue, Mental Health, and Well-Being

OBJECTIVE: This research was conducted to compare short haul (SH) and long haul (LH) pilots regarding sleep restrictions and fatigue risks on flight duty, stress, sleep problems, fatigue severity, well-being, and mental health. METHOD: There were 406 international SH and LH pilots who completed the cross-sectional online survey. Pilots sleep restrictions and fatigue-risk profiles (e.g., time pressure, late arrivals, minimum rest), sleep problems, fatigue severity, well-being, and symptoms of depression, anxiety, and common mental disorders (CMD) were measured and compared for SH and LH pilots. RESULTS: Although SH and LH pilots were scheduled for only 51.465.4% of the legally allowed duty and flight hours, 44.8% of SH pilots reported severe fatigue (FSS 4 to 4.9), and an additional 31.7% high fatigue (FSS 5), compared with 34.7% and 37.3% LH pilots. Considerable sleep problems in 8 nights/mo were reported by 24.6% SH vs. 23.5% LH pilots. Positive depression screenings were reported by 18.1% SH and 19.3% LH pilots. Positive anxiety screenings were reported by 9.6% SH and 5% LH pilots. Of all investigated pilots, 20% reported significant symptoms of depression or anxiety, and 7.23% had positive depression and anxiety screenings. LH pilots reported significantly better well-being than SH pilots. CONCLUSIONS: Our results show that even far less duty and flight hours than legally allowed according to flight time limitations lead to high levels of fatigue, sleep problems, and significant mental health issues among pilots. SH pilots were even more affected than LH pilots. Pilots fatigue should be considered an immediate threat to aviation safety and pilots fitness to fly by promoting fatigue and burnout. Venus M, grosse Holtforth M. Short and long haul pilots rosters, stress, sleep problems, fatigue, mental health, and well-being. Aerosp Med Hum Perform. 2021; 92(10):786797.

Workability, quality of life and cardiovascular risk markers in aging nightshift workers: a pilot study

Background

In aging healthcare professionals, multiple stressors such as night work may affect life and work satisfaction and risk for chronic diseases (e.g. cardiovascular disease [CVD]). In this pilot study we compared workability, quality of life (QoL), and CVD risk markers between night shift and day workers.

Methods

We included 70 hospital employees (mean age 52 ± 4 years, 91.4% female): 32 rotating night shift workers (> 3 nights/month) and 38 permanent day workers. In addition to sociodemographic, lifestyle, and sleep characteristics, we assessed i) workability index (WAI), ii) QoL (World Health Organization Quality of Life [WHOQOL-Bref]) and iii) CVD risk markers, i.e. carotid ultrasound measurements, and biomarkers (NTproBNP, CRP, IL‑6, LDL, ferritin, copper, zinc, and selenium). WAI, QoL, and CVD risk markers were compared between night and day workers. In a subgroup of participants (N = 38) with complete data, we used quantile regression analysis to estimate age and multivariate adjusted differences in biomarker levels.

Results

We found no differences in the domains of QoL (physical health, psychological, social relationships, and environment) and WAI scores between night and day workers. Night shift workers were less likely to report excellent workability than day workers, although differences were not statistically significant. Night shift workers reported more sleep problems (73.1% vs. 55.6%) and tended to have lower zinc levels and higher inflammatory markers (CRP, IL‑6, ferritin), but differences were not significant after adjusting for potential confounders.

Conclusions

Workability, QoL and CVD markers did not significantly differ between rotating night shift and day workers in this small pilot study. Sleep problems and inflammatory marker levels carry implications for occupational health.

Supplementary Information

The online version of this article (10.1007/s00508-021-01928-6) contains supplementary material, which is available to authorized users.

Mental illness and suicide among physicians

The COVID-19 pandemic has heightened interest in how physician mental health can be protected and optimised, but uncertainty and misinformation remain about some key issues. In this Review, we discuss the current literature, which shows that despite what might be inferred during training, physicians are not immune to mental illness, with between a quarter and a third reporting increased symptoms of mental ill health. Physicians, particularly female physicians, are at an increased risk of suicide. An emerging consensus exists that some aspects of physician training, working conditions, and organisational support are unacceptable. Changes in medical training and health systems, and the additional strain of working through a pandemic, might have amplified these problems. A new evidence-informed framework for how individual and organisational interventions can be used in an integrated manner in medical schools, in health-care settings, and by professional colleagues is proposed. New initiatives are required at each of these levels, with an urgent need for organisational-level interventions, to better protect the mental health and wellbeing of physicians.

Impact of night shifts on sleeping patterns, psychosocial and physical well-being among healthcare professionals: a cross-sectional study in a tertiary hospital in Saudi Arabia

BACKGROUND

Shift work and night shifts are very common in healthcare organisations worldwide. However, healthcare professionals doing shift work and night shifts are exposed to several stressors with psychological, social, physical and sleeping consequences. This study aimed to evaluate the effect of night shifts on the psychosocial, physical well-being and sleeping patterns of healthcare professionals in Saudi Arabia.

METHODS

We conducted an observational cross-sectional study from July to September 2019 at King Abdulaziz Medical City, Jeddah, Saudi Arabia. Convenience sampling technique was used to recruit healthcare providers to participate in the study. The outcomes measured included the effect of working hours of healthcare workers on psychosocial and physical health, substance use, and sleep quality and patterns. Pearson's χ² test was used to compare proportions, and Student's t-test/Analysis of variance (ANOVA) was used to examine the mean differences among different demographic groups.

RESULTS

A total of 352 healthcare providers were involved in the study, of whom only 272 were night shift workers. The mean level of job satisfaction was higher among day shift workers than night shift workers: the mean scores were 3.82 (SD=0.93) and 3.48 (SD=1.04), respectively, p=0.007. Moreover, social life was more adversely affected among night shift workers compared with day shift workers: 3.95 (SD=1.11) and 3.61 (SD=1.25), respectively, p<0.030. Likewise, family life was more adversely affected among night shift workers than day shift workers, with a mean of 3.92 (SD=1.10) and 3.50 (SD=1.21), respectively, p<0.006. Around 71% of night shift workers reported having poor-quality sleep compared with 50% of day shift workers (p=0.001).

CONCLUSION

Quality of life is poor among night shift workers than day shift workers, particularly concerning sleep and social and physical outcomes. Further research is needed to investigate factors associated with the quality of sleep and the psychosocial and physical well-being of healthcare professionals working night shifts.

The Effect of Blue-enriched White Light on Cognitive Performances and Sleepiness of Simulated Shift Workers: A Randomized Controlled Trial

BACKGROUND

Shift work is associated with reduced performance and efficiency, the current study aimed at investigating whether blue-enriched white light could improve workers' performance.

METHODS

The study, which adopted a randomized controlled trial, was conducted among 48 simulated shift workers. The participants performed sustained attention task, working memory task, and sleepiness task during night shift work. The data was analyzed using two-way repeated measure ANOVA.

RESULTS

The results indicated that, compared to conventional light, participants' correct responses of the sustained attention significantly increased when they were exposed to blue-enriched white light, correspondingly, the commission errors and omission errors declined. Furthermore, the blue-enriched white light had a significant effect on the decrease of sleepiness. However, the working memory was not significantly affected.

CONCLUSION

Exposing to blue-enriched white light can improve sustained attention and reduce sleepiness.

The impact of 7-hour and 11-hour rest breaks between shifts on heavy vehicle truck drivers' sleep, alertness and naturalistic driving performance

BACKGROUND

An inadequate rest break between shifts may contribute to driver sleepiness. This study assessed whether extending the major rest break between shifts from 7-hours (Australian industry standard) to 11-hours, improved drivers' sleep, alertness and naturalistic driving performance.

METHODS

17 heavy vehicle drivers (16 male) were recruited to complete two conditions. Each condition comprised two 13-hour shifts, separated by either a 7- or 11-hour rest break. The initial 13-hour shift was the drivers' regular work. The rest break and following 13-hour shift were simulated. The simulated shift included 5-hours of naturalistic driving with measures of subjective sleepiness, physiological alertness (ocular and electroencephalogram) and performance (steering and lane departures).

RESULTS

13 drivers provided useable data. Total sleep during the rest break was greater in the 11-hour than the 7-hour condition (median hours [25^th to 75^th percentile] 6.59 [6.23, 7.23] vs. 5.07 [4.46, 5.38], p = 0.008). During the simulated shift subjective sleepiness was marginally better for the 11-hour condition (mean Karolinska Sleepiness Scale [95^th CI] = 4.52 [3.98, 5.07] vs. 5.12 [4.56, 5.68], p = 0.009). During the drive, ocular and vehicle metrics were improved for the 11-hour condition (p<0.05). Contrary to expectations, mean lane departures p/hour were increased during the 11-hour condition (1.34 [-0.38,3.07] vs. 0.63 [-0.2,1.47], p = 0.027).

CONCLUSIONS

Extending the major rest between shifts substantially increases sleep duration and has a modest positive impact on driver alertness and performance. Future work should replicate the study in a larger sample size to improve generalisability and assess the impact of consecutive 7-hour major rest breaks.

Longer Work Shifts, Faster Forward Rotation-More Sleep and More Alert in Aircraft Inspection

The purpose of this intervention study is to compare sleep, alertness, and work ability among aircraft inspectors working under two different shift schedules. The original schedule was forward rotating: MMM – – EEE – NNN – – – (M = morning, E = evening, N = night, – = day off). The new schedule was fast forward rotating: MEN – – with 10-h shifts. The baseline data were collected before the schedule changed, and the follow-up data 12 months (n = 10, Group A) or 5 months (n = 13, Group B) after the change. Three of subjects were women and average age was 46.6 years (range 31–58). The surveys included questions on sleep quantity, sleep quality, severe sleepiness, alertness, perceived stress, current work ability, and satisfaction with the shift schedule. The results indicated that in the new schedule, the sleeping times were longer and sleep loss was less. Moreover, shift specific severe sleepiness decreased, and alertness during shifts improved. Compared to baseline, perceived stress was lower and work ability was better. Satisfaction with the shift system had also improved. To conclude, the quickly forward rotating shift system might be beneficial in terms of increased sleep length and improved alertness and overall well-being especially among older aircraft inspectors.

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

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

Surgeons Maintain Better Focus Working 12-Hour Shifts Compared to 24-Hour Calls

BACKGROUND

In this quality improvement project, we analyzed surgeon focus and attention utilizing a visual tracking device. We hypothesized that surgeons maintained better focus working 12-hour shifts compared to 24-hour calls.

MATERIALS AND METHODS

A prospective, quality improvement project was performed on surgery residents, medical students, and attending physicians working at a busy, tertiary referral, safety-net hospital with Level 1 trauma and burn centers. A visual tracking system was used to measure visual attention before and after a 12-hour, in-house shift and a 24-hour, surgical in-house call. A pupil tracker was utilized to measure attention impairment. Individual performance was rated on a scale of 0 to 6: Severely Impaired- 0; Impaired- 1; Low Average- 2; Average- 3; Above Average- 4; High Average- 5; Superior- 6. Data were analyzed for homogeneity. The Wilcoxon Ranked Sum was used to assess for statistically significant differences between focus scores in the same group of individuals before and after shifts and/or calls. The Mann-Whitney U test was used to compare differences in focus between 12 and 24 hour in-house shifts and/or calls.

RESULTS

A total of 21 surgeons provided a total of 61 visual tracking tests for analysis. Results were found to be nonhomogeneous. The project population was 46% men with a median age of 31 years IQR (28-33). General surgery residents accounted for 48 tests, medical students for 2, and attending surgeons for 11. Average hours of self-reported sleep before the shift/call was 6 (IQR; 6-7). There was almost no overall change in focus in individuals before and after a 12-hour, in-house shift -0.06 (SD 1.9), while after a 24- hour, in-house call, focus decreased by almost 2 full grades -1.8 (SD 1.6) (p = 0.013). There was no statistically significant difference in focus found between 12-hour day shift and 12-hour night shift.

CONCLUSIONS

Twelve-hour shifts appear to preserve focus in surgeons better compared with 24- hour, in-house calls. More research is needed to establish the optimal time of surgeon focus maintenance and shift duration.

Impact of shift work on sleep and fatigue in Maritime pilots

This study examined how objective measures of sleep change across shift-cycles, and the impact of this on sleep quality and fatigue. Forty maritime pilots were recruited from Australian ports. Sleep wake-behaviour (timing and length), and self-reported sleep quality and fatigue, were assessed to determine any impact of roster status and 'on-call' status. On-roster pilots experienced reduced night time sleep duration compared to those off-roster (57 ± 8.8 min), while working on-call also diminished night time sleep duration (126 ± 11.3 min) and quality, compared to workers not on-call. Fatigue scores indicated that participants were not fully recovered prior to commencing rostered night shift, while sleep quality was significantly worse following sleep that occurred after a night shift, compared to after a day shift. These findings potentially support workplace negotiations to change future shift cycles, and to adopt monitoring systems that may mitigate the risk of fatigue-related accidents and chronic health outcomes. Practitioner summary: Long and irregular work hours of maritime pilotage can compromise worker performance and safety. This observational study found that on-roster pilots experience reduced sleep duration compared to those off-roster, while working on-call further diminishes sleep duration and quality. Future workload/fatigue monitoring systems may mitigate fatigue-related accidents and adverse chronic health outcomes. Abbreviations: ANOVA: analysis of variance; ANCOVA: analysis of covariance; BMI: body mass index; CVD: cardiovascular disease; h: hours; mins: minutes; SE: standard error of the mean; SD: standard deviation; SO: sleep opportunities; TST: total sleep time; WASO: wake after sleep onset.

Trends in Strategic Napping in Surgical Residents by Gender, Postgraduate Year, Work Schedule, and Clinical Rotation

OBJECTIVE

To identify surgical resident and clinical rotation attributes which predict on-shift napping through objectively measured sleep patterns and work schedules over a 2-month period.

DESIGN

In a cross-sectional study, participants provided schedules, completed the Epworth Sleepiness Scale (ESS), and wore sleep-tracking devices (Zulu watch) continuously for 8 weeks. Multiple linear regression predicted percent days with on-shift napping from resident and rotation characteristics.

SETTING

Greater Washington, DC area hospitals.

PARTICIPANTS

Twenty-two (n = 22) surgical residents rotating in at least 1 of 5 different clinical rotation categories.

RESULTS

Residents slept 6 hours within a 24-hour period (370 ± 129 minutes) with normal sleep efficiency (sleep efficiency (SE): 87.13% ± 7.55%). Resident ESS scores indicated excessive daytime sleepiness (11.64 ± 4.03). Ninety-five percent (n = 21) of residents napped on-shift. Residents napped on-shift approximately 32% of their working days and were most likely to nap when working between 23:00 and 05:00 hours. Earlier shift start times predicted less on-shift napping (B = -0.08, SE = 0.04, β = -2.40, t = -2.09, p = 0.05) while working more night shifts (B = 1.55, SE = 0.44, β = 4.12, t = 3.52, p = 0.003) and shifts over 24 hours (B = 1.45, SE = 0.55, β = 1.96, t = 2.63, p = 0.01) predicted more frequent on-shift napping.

CONCLUSIONS

Residents are taking advantage of opportunities to nap on-shift. Working at night seems to drive on-shift napping. However, residents still exhibit insufficient sleep and daytime sleepiness which could reduce competency and represent a safety risk to themselves and/or patients. These findings will help inform intervention strategies which are tailored to surgical residents using a biomathematical model of fatigue.

[Consequences of sleep deprivation on healthcare workers]

Healthcare workers doing night shifts are at risk of lack of sleep or/and circadian rhythm disturbances. The ability to make complex rational decisions is reduced with sleep deprivation; thus, one should try to take the proper precautions. This can be done by reducing the complexity and decision speed as much as possible at nights. Furthermore, as suggested in this review, several individual and organisational measures can reduce the risk of circadian rhythm disorders and make the body ready for a new shift more quickly. Driving motor vehicles should be avoided after night shifts with insufficient sleep.

Prevalence of Insomnia in Various Industries and Associated Demographic Factors in Night-Shift Workers Using Workers' Specific Health Examination Data

This study aimed to investigate the prevalence of insomnia in various industries and the associated demographic factors. We searched the nationwide night-shift Workers’ Specific Health Examination (nsWSHE) data extracted in 2015 information on factors associated with insomnia, including sex, age, and the number of workers in the workplace. The prevalence of moderate insomnia in the total industry was 4.6%. Industries with a high prevalence of insomnia included the arts, sports, and recreation-related services industry, followed by the activities of household as employers industry, financial and insurance activities industry, human health and social welfare industry, and accommodation and food services activities industry. The prevalence of insomnia was higher in women. Age was a significant factor. In general, insomnia was highest among those aged ≥60 years. Insomnia was highest in small-sized companies with fewer than five employees compared to large enterprises with more than 1000 employees. This study is the first to analyze the prevalence of insomnia among night-shift workers who participated in the WSHEs. The findings of this study can be used to prioritize intervention policies for insomnia among night-shift workers.

Effects of Long Working Hours and Night Work on Subjective Well-Being Depending on Work Creativity and Task Variety, and Occupation: The Role of Working-Time Mismatch, Variability, Shift Work, and Autonomy

This study explored the effects of long working hours (LW) and night work (NW) on subjective well-being and the modifying effects of work creativity and task variety (WCTV) and occupation. In addition, we examined the influence of working time-related variables including working-time mismatch, variability, shift work, and autonomy on the effects of LW and NW. This study used data from the 5th Korean Working Conditions Survey on 50,205 workers. LW and NW were defined as 52–60 h (L1) or >60 h (L2) per week, and 1–10 days (N1) or >10 days (N2) of night work per month. Multiple logistic regression was used to examine the effects of LW and NW and the modifying influences of WCTV and occupation. Differences in ORs of LW and NW caused by working time-related variables were investigated, to determine effect sizes and directions. A high level of WCTV alleviated the risks of LW and NW. White-collar workers were more vulnerable to the risk associated with NW. Regarding working-time related variables, working-time mismatch and variability increased the risks of LW and NW, respectively, while shift work alleviated the risks of NW. In countries where flexible work systems are not well utilized, working-time autonomy might not be associated with the risk of LW or NW. This study showed that it is necessary to comprehensively consider the occupation and task characteristics of individual workers performing LW or NW. Further studies of the modifying effects of working time-related variables on LW and NW are needed.

Does rearranging meal times at night improve cardiovascular risk factors? An Australian pilot randomised trial in night shift workers

BACKGROUND AND AIMS

Shift workers face an increased risk of cardiovascular disease (CVD), type-2 diabetes and obesity. Eating during the night is a likely contributing factor, as it coincides with the time at which postprandial metabolism is least efficient. In this pilot randomised crossover trial, we examine the effects of a short overnight fast on CVD risk markers (primarily postprandial triglyceride and glucose response) of night shift workers.

METHODS AND RESULTS

Night shift workers with abdominal obesity underwent 4-week intervention and control periods, separated by ≥ 2 weeks washout. In the intervention period, an overnight fast (0100 h-0600 h) was implemented, by redistributing 24-h energy intake. Usual dietary habits were followed in the control period. Outcomes between intervention and control were compared using mixed effects linear regression models. Nineteen adults completed the trial [13 females, mean (±SD) age 41 ± 10 years, BMI 30.7 ± 5.7 kg/m²]. Postprandial triglyceride and glucose response post intervention were not different to post control. The overnight fast was well-tolerated by participants with an adherence rate of 95%, assessed by weekly 24-h dietary recalls. Exploratory analysis indicates lower mean body weight post intervention compared to post control (mean difference: -0.9 kg, 95% CI: -1.3 to -0.4).

CONCLUSIONS

Night shift workers who habitually ate during their night shifts were able to rearrange their meal times to maintain a small overnight fast, which may have promoted small weight changes. This warrants further investigation into the role of meal timing in mitigating the metabolic consequences of night shift work.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (http://anzctr.org.au/) registered on the 30th May 2017 (ACTRN12617000791336).

Shift Work Adaptation Among Police Officers: The BCOPS Study

Few studies have examined shiftwork adaptation among police officers or potential differences in disease biomarkers among adapted and maladapted shiftworkers. This study characterized shiftwork adaptation among 430 police officers from the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) study. Police officers working fixed night shifts with symptoms characteristic of adaptation and maladaptation were identified using latent class analysis (n = 242). Two approaches were applied, one with police-specific symptoms and another using more general symptoms as shiftwork adaptation indicators. Biomarkers of inflammation, heart rate variability, and cardiometabolic risk were then compared between shiftwork adaptation groups, and with officers working day shifts, after adjusting for confounding. When analyses included police-specific symptoms, maladapted shiftworkers (n = 73) had more self-reported stress, sleep disturbances, fatigue, and less social support than adapted shiftworkers (n = 169). Using more general symptoms, maladapted officers (n = 56) reported more stress and depression, and less social support than adapted officers (n = 186). In police-specific models, adjusted (least-squares) means (± standard error) of circulating interleukin-6 (IL-6) concentrations in maladapted officers (0.8 ± 0.1 ln[pg/ml]) were modestly elevated relative to adapted shiftworkers (0.7 ± 0.1 ln[pg/ml], p = .09) and relative to permanent day workers (0.5 ± 0.1 ln[pg/ml], p ≤ 0.01), and leptin levels in maladapted officers (9.6 ± 0.1 ln[pg/ml]) exceeded those in the adapted (9.4 ± 0.1 ln[pg/ml], p ≤ 0.01) and day shift groups (9.4 ± 0.1 ln[pg/ml], p = .03). In the general model, adjusted mean tumor necrosis factor-alpha (TNF-α) concentrations among maladapted officers (5.6 ± 0.23 pg/ml) exceeded the adapted (4.8 ± 0.2 pg/ml, p ≤ 0.01) and day workers (5.0 ± 0.2 pg/ml, p = .04), and insulin among maladapted officers was higher (2.4 ± 0.1 ln[uu/ml]) than the adapted group (1.8 ± 0.1 ln[uu/ml], p = .03). No differences were observed for the other biomarkers. The results suggest that maladaptation among police officers working fixed night shifts may lead to increases in leptin, insulin, IL-6, and TNF-α; however, the cross-sectional design and possible residual confounding preclude interpretation of cause and effect. Prospective studies are planned to further characterize the relationship between shiftwork maladaptation and biomarkers of chronic disease risk in this police officer cohort.

Driving Safety Among Surgical Residents in the Era of Duty Hour Restrictions

OBJECTIVE

Fatigued driving is a known contributor to adverse motor vehicle events (AMVEs), defined as crashes and near misses. Surgical trainees work long and irregular hours; the safety of work-related driving since the introduction of work hour regulations has not yet been studied in this population. We aimed to assess the impact of fatigue on driving safety and explore perceptions of a funded rideshare program.

DESIGN

An electronic survey was delivered and inquired in retrospective fashion about fatigue and sleepiness while driving, occurrences of AMVEs, and projected use of a funded rideshare program as a potential solution to unsafe driving. Chi-square testing determined categorical differences between response choices.

SETTING

Yale University School of Medicine, Department of Surgery, New Haven, CT-a general surgery program with 4 urban clinical sites positioned along a roughly twenty mile stretch of interstate highway in Southeastern Connecticut.

PARTICIPANTS

General Surgery residents at the Yale University School of Medicine.

RESULTS

Of 58 respondents (81% response rate), 97% reported that fatigue compromised their safety while driving to or from work. Eighty-three percent reported falling nearly or completely asleep, and 22% reported AMVEs during work-related driving. Junior residents were more likely than Seniors to drive fatigued on a daily-to-weekly basis (69% vs 47%, p = 0.02) and twice as likely to fall asleep on a weekly-to-monthly basis (67% vs 33%, p = 0.02). Despite this, only 7% of residents had ever hired a ride service when fatigued, though 88%, would use a free rideshare service if provided.

CONCLUSIONS

Work-related fatigue impairs the driving safety of nearly all residents, contributing to frequent AMVEs. Currently, few residents hire rideshare services. Eliminating the cost barrier by funding a rideshare and encouraging its routine use may protect surgical trainees and other drivers.

How the Intensity of Night Shift Work Affects Breast Cancer Risk

Background-In 2019, the IARC concluded that "night shift work is probably carcinogenic to humans (Group 2A), based on limited evidence from human epidemiological studies and sufficient evidence of cancer and strong mechanistic evidence in experimental Animals." The negative health consequences of night shift work may depend on how the night shifts are scheduled. The aim of this study was to investigate how the characteristics of night work affect the risk of developing breast cancer. Methods-A case-control study was conducted in 2015-2019 in the Lodz region. The case group included 494 women with breast cancer, while the control group included 515 healthy women. Results-Night work was found to be the third most important factor regarding breast cancer after a high BMI and a short or no breastfeeding period and before factors such as early menstruation, late menopause, no pregnancy, and smoking. The harmful effects of night work were influenced by its intensity, frequency, rotation, and the number of night shift years worked. Night work increases the breast cancer risk by 2.34 times, and high-intensity night work increases the breast cancer risk by 2.66 times. Conclusions-Appropriate ergonomic recommendations for night shift work for employers should be considered.

The courses of objective physical activity and the association with sleepiness during a 2-week-on/2-week-off offshore shift rotation: an observational repeated-measures study

BACKGROUND

Offshore workers are assumed to have poor health behaviours, but no studies have yet examined physical activity (PA) during a full offshore shift rotation period, including both work and at home periods. Furthermore, the relationship of PA with sleepiness, a prevalent safety hazard offshore, is not known. This study aimed to examine (1) the courses of objectively measured PA in offshore workers during pre-, offshore and post-offshore periods, and (2) the association between PA and self-reported sleepiness.

METHODS

An observational repeated measures study was conducted among 36 offshore workers during a full 2-week on/2-week off offshore shift rotation. Objective PA was assessed using Daytime Activity Averages (DAA) from actigraph recordings. Sleepiness was assessed using next-morning Karolinska Sleepiness Scale (KSS) scores. The courses of PA over time were analysed with Linear Mixed Models (LMM). Parallel LMM were used to assess the longitudinal relationship between PA and sleepiness, both on a between-person and within-person level.

RESULTS

The courses of PA were not significantly different between the pre-, offshore, and post-offshore periods. In addition, between-person trends of PA and sleepiness were not associated (p ranges between 0.08─0.99) and PA did not affect next-morning sleepiness on a within-person level (p = 0.15).

CONCLUSIONS

PA levels during the offshore working period were not different from PA levels at home. Furthermore, PA was not associated with next-morning sleepiness. Further research should focus on different levels of PA including its intensity level.

Health Effects of Night and Irregular Shiftwork: A Longitudinal Cohort Study of US Workers

OBJECTIVES

Evidence suggests that shiftwork results in adverse occupational health outcomes. This paper contributes to the literature by estimating the separate health effects of night and irregular shiftwork on a longitudinal panel of US workers.

METHODS

Data from a 20-year panel of worker surveys from the 1979 National Longitudinal Survey of Youth were used to predict self-reported health limitations related to night and irregular shiftwork using a series of random effects logit models.

RESULTS

Separate and combined specifications of shiftwork as night and irregular effort significantly increase the odds of health limitations compared with working a regular daytime schedule, with more pronounced effects for irregular work (odds ratio [OR] = 1.09 to 1.52) over night shift (OR = 1.03 to 1.14).

CONCLUSIONS

The results suggest that both night and irregular shiftwork may have important negative implications on occupational health, with the deleterious effects particularly pronounced for irregularly scheduled work effort.

A nationally representative study of law enforcement shiftwork and health outcomes

The purpose of this study was to estimate the effect of past and current rotating shift assignments on U.S. law enforcement officers' health outcomes. In a nationally representative sample of 2,867 officers, with an oversample of female officers, we estimated models of sleep quality and fatigue, physical health outcomes, and psychological health outcomes. Further, we examined individual and agency-level factors associated with officers who reported currently working a rotating shift, to investigate what patterns there may be in shift assignments. A history of rotating shift assignments was positively associated with lower sleep quality, and with hypertension, diabetes, and high cholesterol, but not with gastrointestinal disorders, perceived stress, emotional well-being, or suicidality. The associations of shiftwork with health outcomes did not vary by gender. Demographic characteristics did not predict current rotating shift assignments, but a longer history of shiftwork and more working hours did predict a current shift assignment. Attention to mitigating shift system designs as well as the effect of cumulative years of working a rotating shift for the benefit of officer health outcomes is warranted.

Fatigue in the Indonesian rail industry: A study examining passenger train drivers

OBJECTIVE

The railway industry in Indonesia has grown substantially in the past five years, with greater network and tracks length that will double in 2030. There has been a growing concern, however, that fatigue among front-line personnel have not been addressed satisfactorily. This study aimed at evaluating the degree of fatigue among passenger train drivers and suggested practical recommendations to the Indonesian Railway Company.

METHOD

A total of 32 train drivers (driving for about 4 h during the morning or afternoon shifts) agreed to participate in the study. Subjective and objective measures of fatigue (and sleepiness) were obtained prior to, during, and immediately following the end of a duty. Fatigue and driving performance were also determined based on (off-line) analysis of continuous video recordings of the drivers performing the duty.

RESULTS

Fatigue generally increased as a function of time and, for some, 2 h of driving was sufficient in inducing substantial level of fatigue increase. Unlike the morning shift, the afternoon shift was characterized with increased undue fatigue and unacceptable level of performance decrements.

CONCLUSION

In general, fatigue was not found among train drivers working the morning shift. For these drivers, however, there were a couple of individuals with excessive levels of fatigue. The effects of fatigue were more apparent for the afternoon shift. This is possibly due to the degraded sleep quality as a result of split rest periods obtained prior to the duty. It is suggested in this study that the company pay a much closer attention to the work-sleep schedules, and to improve sleep quality by redesigning better sleeping arrangements.