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Objective: Shift work is associated with impaired health and safety but there is a lack of systematic knowledge of shift workers attitude to their shift systems. This may be important for the ability to retain valuable personnel in the company/organization, and to attract new employees. The purpose of the present study was to investigate: the prevalence of shift characteristics (nights, long shifts, short rest, etc.) in traditional shift systems, the workers' attitude to their shift systems, if combinations of problematic shift characteristics are associated with the workers' attitude, and if work stress and poor sleep, fatigue, or social difficulties are associated with attitudes to shift systems. Methods: A representative sample of 3,500 individuals with non-day work in the general population of Sweden were asked to participate in the study. A total of 1965 workers remained after drop-outs. The material was analyzed by Chi2 analysis and hierarchical multiple regression. Results: The results showed that traditional shift systems included many more shift characteristics than those constituting the core of the systems. All included day work, for example. 90.2% of those with roster work had shifts > 10 h at least once a month. 66.9% of those with roster work without nights had < 11 h rest between shifts at least once a month. Less than 25% of the respondents had a rather or very negative attitude to their shift system, with the lowest level for those who work either fixed days or nights (7.6 and 5.7%, respectively) and highest for three-shift work (21.2%) and roster work without night work (24.4%). Shiftwork or roster work with nights had highest levels (> 50%) of sleep problems and fatigue. The difference across shift systems was significant at p <.001 in all cases. Combinations of the most problematic shift characteristics were associated with some increase in negative attitude to the shift schedule. Among schedule characteristics, only long weeks turned out significant in the multivariable regression. The strongest predictor of negative attitude to work hours were social difficulties due to work schedule [ß = 4.98 (95% Confidence interval (Ci) = 3.41, 7.27; p <.001], fatigue caused by schedule (ß = 3.20 Ci = 2.03, 5.05; p <.001), sleep problems caused by schedule (ß = 2.10 Ci = 1.46, 3.01; p =.01), and stressful work (ß = 1.52 Ci = 1.10, 2.11; p <.05). Conclusion: It was concluded that shift systems often included many different shift characteristics, that night shift systems had a large proportion of long shifts, and that split shifts mainly occurred in roster day work. Furthermore, it was concluded that the attitude to the worker's present shift systems seems to be positive for the majority, with the highest level for those who work either fixed days or nights, compared to those who work alternating shifts (including night shifts). Negative attitude to shift systems was more linked to social difficulties, fatigue or sleep problems due to the shift schedule, than to schedule characteristics per se. [ABSTRACT FROM AUTHOR]

Objectives This discussion paper aims to provide scientifically based recommendations on night shift schedules, including consecutive shifts, shift intervals and duration of shifts, which may reduce health and safety risks. Short-term physiological effects in terms of circadian disruption, inadequate sleep duration and quality, and fatigue were considered as possible links between night shift work and selected health and safety risks, namely, cancer, cardio-metabolic disease, injuries, and pregnancy-related outcomes. Method In early 2020, 15 experienced shift work researchers participated in a workshop where they identified relevant scientific literature within their main research area. Results Knowledge gaps and possible recommendations were discussed based on the current evidence. The consensus was that schedules which reduce circadian disruption may reduce cancer risk, particularly for breast cancer, and schedules that optimize sleep and reduce fatigue may reduce the occurrence of injuries. This is generally achieved with fewer consecutive night shifts, sufficient shift intervals, and shorter night shift duration. Conclusions Based on the limited, existing literature, we recommend that in order to reduce the risk of injuries and possibly breast cancer, night shift schedules have: (i) ≤3 consecutive night shifts; (ii) shift intervals of ≥11 hours; and (iii) ≤9 hours shift duration. In special cases - eg, oil rigs and other isolated workplaces with better possibilities to adapt to daytime sleep - additional or other recommendations may apply. Finally, to reduce risk of miscarriage, pregnant women should not work more than one night shift in a week. [ABSTRACT FROM AUTHOR]

BACKGROUND: Shift work has been associated with poor health, sleep and fatigue problems and low satisfaction with working hours. However, one type of shift working, namely split shifts, have received little attention. OBJECTIVE: This study examined stress, health and psychosocial aspects of split-shift schedules among bus drivers in urban transport. METHODS: A questionnaire was distributed to drivers working more than 70% of full time which 235 drivers in total answered. RESULTS: In general, drivers working split-shift schedules (n = 146) did not differ from drivers not working such shifts (n = 83) as regards any of the outcome variables that were studied. However, when individual perceptions towards split-shift schedules were taken into account, a different picture appeared. Bus drivers who reported problems working split shifts (36%) reported poorer health, higher perceived stress, working hours interfering with social life, lower sleep quality, more persistent fatigue and lower general work satisfaction than those who did not view split shifts as a problem. Moreover, drivers who reported problems with split shifts also perceived lower possibilities to influence working hours, indicating lower work time control. CONCLUSIONS: This study indicates that split shifts were not associated with increased stress, poorer health and adverse psychosocial work factors for the entire study sample. However, the results showed that individual differences were important and approximately one third of the drivers reported problems with split shifts, which in turn was associated with stress, poor health and negative psychosocial work conditions. More research is needed to understand the individual and organizational determinants of tolerance to split shifts. [ABSTRACT FROM AUTHOR]

The purpose was to investigate which detailed characteristics of shift schedules that are seen as problems to those exposed. A representative national sample of non-day workers (N = 2031) in Sweden was asked whether they had each of a number of particular work schedule characteristics and, if yes, to what extent this constituted a "big problem in life". It was also inquired whether the individual's work schedules had negative consequences for fatigue, sleep and social life. The characteristic with the highest percentage reporting a big problem was "short notice (<1 month) of a new work schedule" (30.5%), <11 h off between shifts (27.8%), and split duty (>1.5 h break at mid-shift, 27.2%). Overtime (>10 h/week), night work, morning work, day/night shifts showed lower prevalences of being a "big problem". Women indicated more problems in general. Short notice was mainly related to negative social effects, while <11 h off between shifts was related to disturbed sleep, fatigue and social difficulties. It was concluded that schedules involving unpredictable working hours (short notice), short daily rest between shifts, and split duty shifts constitute big problems. The results challenge current views of what aspects of shift work need improvement, and negative social consequences seem more important than those related to health. [ABSTRACT FROM AUTHOR]

Purpose: The aim is to study the influence of change in work-time control (WTC) on work-home interference (WHI) while adjusting for other work-related factors, demographics, changes at work and WHI at baseline among women and men. An additional aim was to explore sex differences in the relation between change in WTC and WHI. Methods: The study included working participants of the Swedish Longitudinal Occupational Survey of Health (SLOSH) study of the third (2010) and fourth (2012) waves ( n = 5440). Based on a seven-item index, four groups of WTC were formed: stable high (40 %), stable low (42 %), increasing (9 %), or decreasing (9 %) WTC over the 2 years. WHI was measured by four items and individuals were categorised in whether suffering or not suffering of WHI. Sex-stratified logistic regression analyses with 95 % confidence intervals (CI) were used to estimate the odds of experiencing WHI by change in WTC. Results: Controlling for demographics and work-related factors, women with stable low (OR = 1.46; 95 % CI 1.14-1.88) and women and men with decreasing WTC (women OR = 1.99; 95 % CI 1.38-2.85; men OR = 1.80; 95 % CI 1.18-2.73) had higher odds of WHI than those with a stable high WTC. Additionally, adjusting for changes at work and WHI at baseline did not alter the results substantially. Interaction analysis did not reveal any significant sex difference in the relation between WTC and WHI. Conclusions: For both women and men decreased and for women only, low control over working hours resulted in WHI also after adjusting for work-related factors and demographics. [ABSTRACT FROM AUTHOR]

Aims: Past research has often neglected the sub-dimensions of work time control (WTC). Moreover, differences in levels of WTC with respect to work and demographic characteristics have not yet been examined in a representative sample. We investigated these matters in a recent sample of the Swedish working population. Methods: The study was based on the 2014 data collection of the Swedish Longitudinal Occupational Survey of Health. We assessed the structure of the WTC measure using exploratory and confirmatory factor analysis. Differences in WTC by work and demographic characteristics were examined with independent sample t-tests, one-way ANOVAs and gender-stratified logistic regressions. Results: Best model fit was found for a two-factor structure that distinguished between control over daily hours and control over time off (root mean square error of approximation = 0.06; 95% CI 0.04 to 0.09; Comparative Fit Index (CFI) = 0.99). Women, shift and public-sector workers reported lower control in relation to both factors. Age showed small associations with WTC, while a stronger link was suggested for civil status and family situation. Night, roster and rotating shift work seemed to be the most influential factors on reporting low control over daily hours and time off. Conclusions: Our data confirm the two-dimensional structure underlying WTC, namely the components ‘control over daily hours’ and ‘control over time off’. Women, public-sector and shift workers reported lower levels of control. Future research should examine the public health implications of WTC, in particular whether increased control over daily hours and time off can reduce health problems associated with difficult working-time arrangements. [ABSTRACT FROM AUTHOR]

Seafarer sleepiness jeopardizes safety at sea and has been documented as a direct or contributing factor in many maritime accidents. This study investigates sleep, sleepiness, and neurobehavioral performance in a simulated 4 h on/8 h off watch system as well as the effects of a single free watch disturbance, simulating a condition of overtime work, resulting in 16 h of work in a row and a missed sleep opportunity. Thirty bridge officers (age 30 ± 6 yrs; 29 men) participated in bridge simulator trials on an identical 1-wk voyage in the North Sea and English Channel. The three watch teams started respectively with the 00-04, the 04-08, and the 08-12 watches. Participants rated their sleepiness every hour (Karolinska Sleepiness Scale [KSS]) and carried out a 5-min psychomotor vigilance test (PVT) test at the start and end of every watch. Polysomnography (PSG) was recorded during 6 watches in the first and the second half of the week. KSS was higher during the first (mean ± SD: 4.0 ± 0.2) compared with the second (3.3 ± 0.2) watch of the day ( p < 0.001). In addition, it increased with hours on watch ( p < 0.001), peaking at the end of watch (4.1 ± 0.2). The free watch disturbance increased KSS profoundly ( p < 0.001): from 4.2 ± 0.2 to 6.5 ± 0.3. PVT reaction times were slower during the first (290 ± 6 ms) compared with the second (280 ± 6 ms) watch of the day ( p < 0.001) as well as at the end of the watch (289 ± 6 ms) compared with the start (281 ± 6 ms; p = 0.001). The free watch disturbance increased reaction times ( p < 0.001) from 283 ± 5 to 306 ± 7 ms. Similar effects were observed for PVT lapses. One third of all participants slept during at least one of the PSG watches. Sleep on watch was most abundant in the team working 00-04 and it increased following the free watch disturbance. This study reveals that-within a 4 h on/8 h off shift system-subjective and objective sleepiness peak during the night and early morning watches, coinciding with a time frame in which relatively many maritime accidents occur. In addition, we showed that overtime work strongly increases sleepiness. Finally, a striking amount of participants fell asleep while on duty. [ABSTRACT FROM AUTHOR]

This dedicated issue of Chronobiology International is devoted to the selected proceedings of the 20th International Symposium on Shift Work and Working Time held in Stockholm, Sweden, 28 June to 1 July 2011. It constitutes the fifth such issue of the journal since 2004 dedicated to the selected proceedings to the meetings of the Working Time Society. The key theme of the 20th Symposium was 'Biological Mechanisms, Recovery, and Risk Management in the 24-h Society.' The collection of papers of this dedicated issue represents the best of contemporary research on the effects of night and rotating shift schedules on worker health and safety. The contents cover such topics as sleep restriction, injuries, health, and performance of night work and rotating shiftwork, plus light treatment as a countermeasure against the circadian disruption of shiftwork. The majority of the papers are observational field studies, including some of large sample size, and three studies are well-designed laboratory experiments. (Author correspondence: ) [ABSTRACT FROM AUTHOR]

The article focuses on a survey to find the role of night work, fatigue and sleepiness in traffic accidents. As mentioned, the survey was conducted on traffic and local police officers as well as prosecutors. It informs that the aim of survey was to understand the law which is applicable to prohibit fatigued driving. It also mentions that shift workers including police officers break the law while driving home after a night shift.

Abstract: Previous studies indicate that the effect of a given shift schedule may depend on individual factors. The aim of the present study was to investigate whether a misfit between individual preferences and actual working hours affected the association between working hours and self-reported indicators of health and well-being. The study population consisted of 173 female eldercare workers who mainly worked day or evening shifts. We combined self-reported questionnaire data on preferences with actual work schedules during a four-week period. The study showed that a misfit between preferences on one hand and “non-day work”, “weekend work” or “only a few consecutive days off” on the other hand was associated with an increased dissatisfaction with working hours and/or an increase in the intention to leave the workplace due to one''s working hours. [Copyright &y& Elsevier]

Very little is known about the effects on sleep and sleepiness of entering or exiting shiftwork. The present study used a longitudinal database (n = 3637). Participants completed a questionnaire on work hours, sleep, and work environment at the start and end of a 5-yr period. Changes in shift/day work status were related to change in a number of subjective sleep variables using logistic regression analysis. The analyses were adjusted for age, sex, and differences in socioeconomic status, work demands, work control, physical workload, marriage status, and number of children. In comparison with constant day work, entering shiftwork (with or without night shifts) from day work increased the risk of difficulties in falling asleep, and leaving shiftwork reduced this risk (odds ratio [OR] = 2.8 [confidence interval, CI = 1.8–4.5]). Also falling asleep at work showed a consistent pattern; an increased risk of falling asleep for those with shiftwork on both occasions, and for those with night work on both occasions. Also entering night work was associated with a strongly increased risk of falling asleep at work (OR = 2.9 [CI = 1.3–6.7]). These results suggest that entering and leaving shiftwork has a considerable impact on sleep and alertness. However, there is a need for large and more extended longitudinal studies to support our findings. (Author correspondence: ) [ABSTRACT FROM AUTHOR]

In this narrative review, we examined what level of research evidence is available that shift workers' sleep-wake disturbances can be minimized through ergonomic shift scheduling. We classified the pertinent studies conducted on real shift workers in field conditions by the type of shift system and study design (ie, whether the shift systems were modified or not - "treatment" versus "no treatment"). The results of the observational studies in which no changes to the shift system were made (ie, no treatment) showed that, irrespective of the shift system, night and early-morning shifts and quick returns are associated with short sleep and increases in sleepiness. The same is true for very long shifts (>16 hours) and extremely long weekly working hours (>55 hours). For all categories of shift systems, there were a lack of controlled intervention studies, limiting the possibility to provide solution-focused recommendations for shift scheduling. Most of the controlled intervention studies had been conducted on workers under regular 3-shift systems. These studies suggested that a change from slowly backward-rotating shifts to rapidly forward-rotating shifts is advantageous for alertness and, to some degree, sleep. We also found that a change from an 8- to 12-hour shift system does not necessarily result in impairments in the sleep-wake pattern. The level of research evidence was affected by many of the studies' frequent methodological limitations in measuring sleep and sleepiness. In all, to have reliable and solution-focused recommendations for shift scheduling, methodologically sound controlled intervention studies are required in different categories of shift systems. [ABSTRACT FROM AUTHOR]

The article discusses various reports published within the issue including one by Beate Pesch and colleagues on the correlation between long-term night work and increase risk of breast cancer, one by Yasushi Suwazono and team on the effects of shift work which reveal five percent increase in blood cholesterol levels in Japanese workers aged 21 years old and above, and one by Anders Knutsson and Henrik Bøggild on the correlation of shift work on peptic ulcer diseases.

Very little is known about differences in sleep between day and shift workers in representative samples of the population. This study compared a national representative sample (N=3400) of shift (with night shifts) and day workers regarding the different types of sleep disturbances and also the level of sleep symptoms with that of insomnia patients. The results showed very few differences between shift and day workers; only “too little sleep” and “nodding off at work” were marginally higher among shift workers. The results also showed that the complaints of insomnia patients for most sleep disturbances corresponded to the 2nd-16th percentile of the shift workers' levels of complaints. The results suggest, at least with the present questionnaire methodology, that shift work does not appear to be a major source of sleep disturbances and that their complaint levels bear no resemblance to those seen in insomniac patients. [ABSTRACT FROM AUTHOR]

The article focuses on a study addressing the effects of flexible shift system based on self-determined work hours with respect to sleep/wake complaints and subjective health in police officers. The secondary aim was to analyze the relation between work hour characteristics indicating compressed or difficult rosters and subjective sleep and sleepiness within the flexible shift system group. Results showed that the group did not differ with respect to sleep/wake complaints and subjective health.

Shift work increases the risk for developing cardiovascular disease. There is, however, little knowledge of what aspects of shift scheduling that are detrimental and what characteristics promote good health. The aim of the present study was to evaluate whether coronary risk factors deteriorate after a hard work period and whether recovery, in the form of a week off, was sufficient to improve them. A total of 19 women worked an extremely rapidly rotating and clockwise shift schedule at a paper and pulp factory. They underwent two health examinations, one at the end of the work period and one after the week off. In addition, the women were divided into a tolerant and a vulnerable group, depending on their satisfaction with their work hours. Most risk factors did not change, but total cholesterol and low‐density lipoprotein (LDL)‐cholesterol were lower after the working period than after the week‐off. In addition, vulnerable women had higher levels of total cholesterol and a higher ratio of total cholesterol/high‐density lipoprotein (HDL) than tolerant ones. In conclusion, the finding that a week‐off worsens cholesterol levels was against our hypothesis and suggests further studies on how activities/responsibilities outside the workplace affect shift‐working women. It was also shown that susceptible shift workers had worse lipid profiles. [ABSTRACT FROM AUTHOR]

The present study aimed to provide subject-specific estimates of the relation between subjective sleepiness measured with the Karolinska Sleepiness Scale (KSS) and blink duration (BLINKD) and lane drifting calculated as the standard deviation of the lateral position (SDLAT) in a high-fidelity moving base driving simulator. Five male and five female shift workers were recruited to participate in a 2-h drive (08:00–10:00 hours) after a normal night sleep and after working a night shift. Subjective sleepiness was rated on the KSS in 5-min intervals during the drive, electro-occulogram (EOG) was measured continuously to calculate BLINKD, and SDLAT was collected from the simulator. A mixed modelanova showed a significant ( P < 0.001) effect of the KSS for both dependent variables. A test for a quadratic trend suggests a curvilinear effect with a steeper increase at high KSS levels for both SDLAT ( P < 0.001) and BLINKD ( P = 0.003). Large individual differences were observed for the intercept ( P < 0.001), suggesting that subjects differed in their overall driving performance and blink duration independent of sleepiness levels. The results have implications for any application that needs prediction at the subject level (e.g. driver fatigue warning systems) as well as for research design and the interpretation of group average data. [ABSTRACT FROM AUTHOR]

The present study aimed to experimentally evaluate the effect of early morning shifts on sleep and sleepiness of train drivers during normal working conditions. A total of 17 experienced train drivers were studied during a 4.5 h drive in two directions with a 2.5 h break in between on three different shifts: an early shift that started at 05:49 h (train left at 06:18 h) and ended at 17:41 h, a day shift (07:49–19:41 h), and an evening shift (09:49–21:41 h). Retrospective (since the last stop) ratings of mean sleepiness and peak sleepiness (Karolinska Sleepiness Scale—KSS: 1 = very alert, 9 = very sleepy, fighting sleep, difficulty staying awake) were assessed at each stop during the drive. The results showed that sleep length was reduced (p < 0.001) by 1 h and 2 h, respectively, by the early shift compared to the day and evening shifts. The prevalence of severe sleepiness (KSS ≥ 7) was high, especially during the early shift when 14 (82%) subjects reported at least one event during the drive. Application of the Generalized Linear Mixed Models (GLMM) to the sleepiness data showed that there was an increased risk for severe sleepiness during the early shift (OR = 4.9) that increased further with the length of the drive between stops (OR = 1.9, 15 min), suggesting an interaction between early morning shift and monotony. The findings have practical implications in risk assessment. Long drives without stops and other monotonous situations should have a higher risk rating for severe sleepiness in shifts with an early start before 06:00 h, compared to shifts that begin 2 h later. [ABSTRACT FROM AUTHOR]

Despite results linking shift work with ill health, only a few studies have addressed its relation with mortality. The purpose of the present study was to examine the hypothesis that shift work is a predictor of mortality. The study involved a sample of 22,411 individuals of the Swedish population. Data were obtained through annual phone interviews done between 1979 and 2000. Cox regression analysis was used to assess the association between shift work/day work as the independent variable and death/survival during the subsequent years as the dependent variable. Separate analyses were carried out for female and male white- and blue-collar workers, respectively. The results were adjusted for age, stress, physical work load, disease at the outset of the study, and smoking. Mortality was significantly increased for female white-collar workers, with a Hazard Ratio of 2.61 and a 95% confidence interval of 1.26–5.41. No other significant effects were found. It is concluded that blue-collar shift work is not related to mortality, but that risk of death is increased for women white-collar shift workers compared to women white-collar day workers. [ABSTRACT FROM AUTHOR]

Objectives. There is limited knowledge as to why some individuals tolerate shift work and others do not. As a consequence of their intolerance, many individuals develop dissatisfaction with their shift schedule. To evaluate if dissatisfaction with one’s shift system was related to alterations of the daily pattern of sleep and sleepiness, we followed two groups of shift workers that were either highly satisfied or dissatisfied with their shift schedule, during an entire shift cycle. Methods. Thirty-six male and 20 female shift workers were selected according to their satisfaction with their shift schedule. The shift cycle included seven work periods (“triads” of shifts; night shift—afternoon shift—morning shift), with only 8–9 hours off (quick returns) between shifts, but followed by a day off. Results. Sleep length was reduced after night shifts (4.8 h) and afternoon shifts (5.4 h). Sleepiness was increased during all shifts, particularly night shifts. Sleepiness did not accumulate across the shift cycle even though sleepiness was slightly increased directly after the last triad of shifts. There were few significant gender differences. Dissatisfied shift workers reached much higher levels of sleepiness and reported less sufficient sleep, but not objectively poorer or shorter sleep. Amongst dissatisfied workers, this resulted in an increase of sleepiness problems across shifts within the triad of shifts. Dissatisfied workers also had more performance lapses at the end of the night shift. Conclusions. Satisfaction with the shift schedule seems to reflect how well the shift workers were coping with the schedule. It is suggested that the increase of sleep/wake problems within the work period for the dissatisfied shift workers is related to increased sensitivity to curtailed and displaced sleep. [ABSTRACT FROM AUTHOR]

Compares satisfied and dissatisfied shift workers with respect to major anabolic and catabolic hormones. Lower morning testosterone levels of dissatisfied shift workers than satisfied ones; Association of low testosterone levels with greater sleep need, distirbed sleep and increased need for recovery after the work period.

In this cross-sectional study associations were examined between eight shift schedule characteristics with shift-specific sleep complaints and need for recovery and generic health and performance measures. It was hypothesized that shift schedule characteristics meeting ergonomic recommendations are associated with better sleep, need for recovery, health and performance. Questionnaire data were collected from 491 shift workers of 18 companies with 9 regular (semi)-continuous shift schedules. The shift schedule characteristics were analyzed separately and combined using multilevel linear regression models. The hypothesis was largely not confirmed. Relatively few associations were found, of which the majority was in the direction as expected. In particular early starts of morning shifts and many consecutive shifts seem to be avoided. The healthy worker effect, limited variation between included schedules and the cross-sectional design might explain the paucity of significant results. [ABSTRACT FROM AUTHOR]