Cardiovascular risk factors and primary selection into shift work

OBJECTIVES: This study examined differences between future shift workers and future day workers as regards cardiovascular risk factors before they began different work schedules and the differences that remained after control for sociodemographic factors and general self-efficacy. METHODS: Altogether 2870 newly educated social and health care workers filled out a questionnaire a few weeks before finishing their formal training and again 1 year after graduation. They answered questions on diabetes, hypertension, lifestyle habits, sociodemographic factors, and general self-efficacy. RESULTS: In the unadjusted analyses, baseline obesity was associated with fixed evening work at follow-up. Minimal or light-to-moderate leisure-time physical activity was associated with a decrease in the odds ratio (OR) for two or three shifts including night work. Smoking status was associated with fixed evening work, fixed night work, and two- or three- shift work including night work. After adjustment for sociodemographic factors and general self-efficacy, smoking was prospectively associated with fixed evening work [OR 1.56, 95% confidence interval (95% CI) 1.21-2.02] and fixed night work (OR 1.64, 95% CI 1.04-2.56). Being an ex-smoker was associated with two- or three-shift work including night work (OR 1.85, 95% CI 1.28-2.68). The association between two- and three-shift work and smoking was only of borderline significance (OR 1.37, 95% CI 1.00-1.87). CONCLUSIONS: Compared with future day workers, fixed evening or fixed night workers already smoked more before they began shift work. Being an ex-smoker was significantly associated with two- or three-shift work including night work. These results indicate that smoking status should not solely be treated as a mediator between some variants of shiftwork schedules and cardiovascular diseases but should also be considered a confounder.     

Atypical work schedules are associated with poor sleep quality and mental health in Taiwan female nurses

Purpose

To investigate the effects of shift work schedules on sleep quality and mental health in female nurses in south Taiwan.

Methods

This study recruited 1,360 female registered nurses in the Kaohsiung area for the first survey, and among them, 769 nurses had a rotation shift schedule. Among the 769 rotation shift work nurses, 407 completed another second survey 6–10?months later. Data collection included demographic variables, work status, shift work schedule, sleep quality (Pittsburgh Sleep Quality Index), and mental health (Chinese Health Questionnaire-12).

Results

Nurses on rotation shift had the poor sleep quality and mental health compared to nurses on day shift. The nurses on rotation shift had a relatively higher OR of reporting poor sleep quality and poor mental health (OR, 2.26; 95% CI, 1.57–3.28; and OR, 1.91; 95% CI, 1.39–2.63, respectively). Additionally, rotation shift nurses who had ≥2?days off after their most recent night shifts showed significantly improved sleep quality and mental health (PSQI decreased of 1.23 and CHQ-12 decreased of 0.86, respectively). Comparison of sleep quality between the first and second surveys showed aggravated sleep quality only in nurses who had an increased frequency of night shifts.

Conclusion

Female nurses who have a rotation shift work schedule tend to experience poor sleep quality and mental health, but their sleep quality and mental health improve if they have ≥2?days off after their most recent night shifts. This empirical information is useful for optimizing work schedules for nurses.     

Conflict between work and family roles and satisfaction among nurses in different shift systems in Croatia: a questionnaire survey

The objective of this study was to examine the perception of conflict between work and family roles and job, family, and life satisfaction among nurses in Croatia. One hundred and twenty-nine nurses (married mothers) working in hospitals in Zadar, ?ibenik, and Split were divided in four groups according to their worktime schedule. The participants completed a survey, which included a set of sociodemographic-type questions, questions about the level and allocation of family responsibilities between spouses, and scales measuring the perceived negative effects of worktime, psychological demands of the work, work-family conflict, and semantic differential scales for measuring the affective and cognitive-evaluative component of job, family, and life satisfaction. This was the first study in Croatia to deal with work-family conflict among nurses or workers with different shift systems.The results of this study indicate that nurses working morning shifts only experienced less conflict between work and family than other groups of nurses, who worked the morning, afternoon, and the night shift. The cognitive-evaluative component of job satisfaction was the highest among morning shift nurses and the lowest in nurses who worked 12-hour shifts, while the affective component of life satisfaction was the lowest in nurses working irregular and backward rotated shifts. These results confirm that shiftwork makes the work-family role conflict even worse. They also support the view that the type of shift rotation matters.     

Antecedents and consequences of work-family conflict: a prospective cohort study

This study examined both risk factors for the onset of work-family conflict and consequences in terms of need for recovery and prolonged fatigue for men and women separately. Two-year follow-up data from the Maastricht Cohort Study on "Fatigue at Work" (n = 12,095) were used. At baseline, the prevalence of work-family conflict was 10.8% (9.0% in women; 11.1% in men), the cumulative incidence at 1 year follow-up was 5.1%. For men, several work-related demands, shift work, job insecurity, conflicts with coworkers or supervisor, having full responsibility for housekeeping, and having to care for a chronically ill child or other family member at home were risk factors for the onset of work-family conflict, whereas decision latitude and coworker and supervisor social support protected against work-family conflict. In women, physical demands, overtime work, commuting time to work, and having dependent children were risk factors for work-family conflict, whereas domestic help protected against work-family conflict at 1 year follow-up. Work-family conflict was further shown to be a strong risk factor for the onset of elevated need for recovery from work and fatigue.     

Do weekly and fast-rotating shiftwork schedules differentially affect duration and quality of sleep?

 Characteristics of shiftwork schedules can have distinct impacts on workers’ sleep. This report presents comparisons of the effects of two different shiftwork schedules on duration and quality of the main sleep episodes in comparable worker populations at two different petrochemical plants. No significant differences were found for sleep duration in comparing the two plants. However, within each plant’s shift cycles, morning and night shifts showed shorter sleep durations than all other workdays and days off. Quality of sleep was perceived as lowest for night shifts of both plant schedules, and of lesser quality for weekly than for fast-rotating shifts. These results support recommendations for reducing the number of consecutive nights of shiftwork. However, before recommending any optimal shift schedule, interactions of sleep duration and quality with shift schedules need much further evaluation. Received: 18 December 1995/Accepted: 18 July 1996     

Shiftwork: what health care managers need to know

Shiftwork is one of health care worker's oldest problems and is known to have important implications on health. Health risks are compounded with age and the amount of cumulated shiftwork. No shift system is clearly advantaged, yet the worker's ability to choose the shift system seems to maximize adaptation to shiftwork. When designing a work schedule, it is important to take into consideration the shift pattern, length of the shift, and the number of consecutive days worked. A poorly designed work schedule can impact the quality of care, the personal and professional outcomes for health care workers, patient satisfaction, length of stay, unplanned absenteeism, cost effectiveness, and productivity. Long-term studies of shiftworkers may disproportionately represent workers who have adapted to shiftwork. Self-scheduling is an interesting alternative in the quest for a more responsive work environment and is a strategy for retention among new, mid-career, and senior nurses. Planned on-site napping may be a useful tool to combat the pernicious effects of sleep debt on performance. Guidelines must be developed and initiatives implemented and evaluated to protect health care workers, especially older female shiftworkers, from the negative impact of shiftwork as they represent a precious resource in a shrinking supply.     

Rescheduling a three shift system at a steel rolling mill: effects of a one hour delay of shift starting times on sleep and alertness in younger and older workers.

OBJECTIVE: To evaluate a new work schedule at a Finnish steel mill with special attention to effects on older workers. The schedule was designed to improve sleep before the morning shift, and alertness during the morning shift, by delaying shift start and end times. METHODS: Evaluation was by a shiftwork health and safety questionnaire, recordings of work-rest-sleep cycles with activity monitors worn on the wrist, daily diaries, and on site computerised testing of fatigue and alertness by the NIOSH fatigue test battery. RESULTS: The one hour delay in shift starting times improved sleep before the morning shift, and improved waking fatigue, sleepiness, and performance during the morning shift. Evening and night shift sleep and fatigue or sleepiness, however, were affected negatively by the new work schedule, but the results for those shifts were less consistent across the various measures. Despite the improvements, most workers were not satisfied with the new schedule because of social concerns. Few interactions of age with the new work schedule were found, suggesting that the effects of the work schedule were uniform across age groups. CONCLUSION: A change of as little as one hour in shift starting times can improve morning shift sleep and alertness, but there are trade offs from these improvements in terms of night shift effects and social considerations. It seems, then, that optimal shift start and end times for an entire organisation are difficult to institute on a wide scale. Tailoring shift schedules to subgroups within an organisation is suggested.     

Questionnaire survey of masters, mates, and pilots of a State Ferries System on health, social, and performance indices relevant to shift work.

A questionnaire survey of health, social, and performance indices related to shiftwork among masters, mates, and pilots of a State Ferries System was performed in response to a joint request from labor and management. The questionnaire results for the group as a whole resembled those reported for other groups of shiftworkers. Significantly more sick days, dissatisfaction with work schedules, poor sleep patterns, physician consultations for insomnia, and reports of errors of judgement and near misses attributed to fatigue were reported on the ferry run with one of the most erratic schedules compared to all other runs, suggesting the need for further study.     

What do petrochemical workers, healthcare workers, and truck drivers have in common? Evaluation of sleep and alertness in Brazilian shiftworkers

The article reports briefly on some effects of shiftwork and the work environment on health and wellbeing of shiftworkers. Studies of Brazilian shiftworkers (healthcare workers, petrochemical workers, and truck drivers) are described. A similar methodology was used to evaluate sleep and alertness in all these studies. The evaluation of sleep duration and quality and alertness showed similar results in the three studies. Although the workers were in different work settings, performing different jobs, the results are similar: daytime sleep is reduced and perceived as having worse quality than nighttime sleep; alertness decreases as the night work progresses. The study highlights the importance of shiftwork schedules' features and work organization for workers' health, wellbeing, and safety.     

Prevalence of common infections among employees in different work schedules

This study examined the prevalence of common infections among employees in different work schedules. Self-administered questionnaire data from the Maastricht Cohort Study on "Fatigue at Work" (n = 12,140) were used. Job title was used as a matching variable between day and shift workers to control for their different work environment. We used a multilevel analysis of a two-level structure, in which the individual employees (level 1) were nested within job titles (level 2), adjusted for demographics, longstanding disease, health behavior, work-related factors, fatigue and sleep quality. Results from the multilevel analyses showed that, compared to day work, shift work was associated with a higher risk for common infections, with the highest risk in three-shift workers. Compared to day work, shift work was further associated with differences in health, health behavior, sleep, fatigue and perceived job characteristics, factors that may influence the occurrence of infections and should be taken into account in future studies as well.     

Comparison of sleep-related cardiac autonomic function between rotating-shift and permanent night-shift workers

The purpose of this study was to explore whether sleep-related cardiac sympathetic activity is significantly lower in rotating shift workers than in permanent night shift workers, in order to evaluate whether shift work is preferable to permanent night work. Our sample comprised of twelve permanent night shift nurses and twelve rotating three-shift nurses. All female nurses slept in their dormitories, where they were allowed to sleep and wake spontaneously. All sleep parameters were recorded and analyzed using an ambulatory polysomnographic recorder. No significant differences were identified between permanent night shift (PNS) nurses and rotating three-shift (RTS) nurses in terms of basic demographics and sleep patterns. The low frequency (LF) of PNS nurses was significantly higher than that of RTS nurses during both daytime sleep and wakefulness, as was the low-to-high frequency ratio (LF/HF) during both nighttime sleep and wakefulness. PNS nurses also exhibited significantly higher LF and LF/HF during the first to third episode of non-rapid eye movement (NREM1-3) sleep, and the first episode of rapid-eye movement (REM1) sleep. PNS nurses had higher sympathetic activity during nighttime and daytime sleep than did RTS nurses. These results suggest that a rotating three-shift schedule may be preferable to permanent night work in terms of cardiac autonomic regulation.     

Workers' sleep quality as determined by shift system and demographic factors

The present paper is based on the results of a study conducted to examine whether there are any differences in sleep quality between permanent day workers and rotating shift workers working under two- and three-shift systems. Influences of demographic variables such as subjects' age and experience on sleep were also explored. The subjects studied consisted of 125 permanent day workers, 125 fortnightly rotating two-shift workers, and 50 weekly rotating three-shift workers. The method of data collection was that of field study through questionnaire. The results show that, compared to the permanent day workers, sleep quality is poorer for the rotating shift workers and, between the two groups of shift workers, it is poorer for the three-shift workers. These findings imply that a discontinuous two-shift system (without night work) is more convenient than a continuous three-shift system (including night work).     

Health and performance factors in health care shift workers

OBJECTIVES: To assess the impact of shift work on health care workers. SUBJECTS AND METHODS: A cross-sectional study assessed health and performance markers of 188 day and night shift nonphysician health care workers. RESULTS: Night-shift workers were more likely to report difficulty with routine orders, lower energy levels, unpredictable work schedules, and sleep disturbance but no difference with injuries or motor vehicle crashes. A classification of day shift, night shift without unpredictable schedule or sleep problems, and night shift with unpredictable schedule or sleep problems revealed a trend of increased difficulty with routine orders, suggesting a "dose response effect." CONCLUSIONS: Findings suggest an association with night shift health care workers and adverse health and performance markers. A "higher-risk" subgroup may benefit from targeted interventions to reduce potential adverse effects from shift work and improve health care delivery.     

Anxiety about starting three-shift work among female workers: findings from the Female Shift Workers' Health Study

In 1999, the Japanese Law on Equal Employment Opportunity and Conditions was amended and the previous prohibition of the assignment of female workers to night work was abolished. Subsequently, the number of female shift workers has been increasing in Japan, necessitating greater attention to the health care of this population. The aim of the current study is to evaluate the relationship between anxiety expressed about starting three-shift work and background characteristics among female workers who were being assigned to three-shift work for the first time. The subjects were 38 middle-aged female workers (age range: 44 to 59 years) who were working at a chemical plant. The women completed a self-administered questionnaire before starting three-shift work. Levels of anxiety about starting three-shift work were assessed by the question 'Do you feel anxious about starting three-shift work?' The available responses were: 'Very agree', 'Considerably agree', 'Rather agree', 'Slightly agree' and 'Not agree at all', and 63% of the subjects gave one of the first two answers, which were defined as indicating anxiety. We also acquired information regarding lifestyle and occupation for each subject, including the following factors: frequency of breakfast consumption, subjective sleep insufficiency, previous experience of similar work before beginning shift work, previous experience of two-shift work, and responsibility for household duties. In the study, we found a marginally statistically significant trend association between frequent breakfast consumption and anxiety about starting three-shift work (P(trend) = 0.09). Anxiety was also high among subjects with sleep disorders, especially those suffering from subjective sleep insufficiency (P = 0.08). Due to the small study population, these results should be interpreted with caution and confirmed by future studies.     

Health effects of transitions in work schedule, workhours and overtime in a prospective cohort study

OBJECTIVES: The aim of this study was to examine the longitudinal relationship between transitions in work schedules, workhours and overtime and changes in several self-reported health outcomes (general health, fatigue, need for recovery, and psychological distress). METHODS: Three-year follow-up data from the Maastricht Cohort Study on fatigue at work were used. Gender-stratified logistic regression analyses using generalized estimating equations were conducted for each of the dichotomized health outcomes, with control for a range of possible confounding factors. RESULTS: In this study, transitions in worktime arrangements were prospectively related to changes in several self-reported health outcomes. Substantial and significant associations were found for transitions in work schedule and the incidence of prolonged fatigue and for the need for recovery among men. Moreover, transitions in workhours affected the need for recovery among men, while they influenced general health and psychological distress among women. Finally, transitions in overtime were significantly associated with the incidence of the need for recovery among both men and women and with the incidence of psychological distress among men only. CONCLUSIONS: Transitions in worktime arrangements are related to changes in health, and studying transitions might be an important means of gaining insight into a possible causal relationship between employment and health. Given the considerable impact of worktime arrangements on the individual worker, employers, and society and the high frequency in which transitions within worktime arrangements can occur, these findings underline the need for interventions addressing worktime arrangements in order to reduce or prevent their impact on employee health.     

Effects of shift work on quality of sleep among retired workers]

To examine the relationship between shiftwork experience and quality of sleep after retirement, we carried out a self-reported questionnaire survey on 777 retired workers of a manufacturing company. Questionnaire items included past illness, current health status, dietary habit, alcohol drinking, smoking, regular exercise, sleep, working condition (job, shift work experience, shift work periods and side job), current working status, social activity, educational background, sex, age and number of years since retirement. Present health status (adjusted odds ratio 4.318, 95% CI 2.475-7.534), shift work experience (2.190, 1.211-3.953), present working status (1.913, 1.155-3.167) and dietary habit (1.653, 1.055-2.591) were significantly related to sleep disturbance after retirement by multiple logistic regression analysis. To prevent sleep disturbance after retirement, people should keep a regular lifestyle and good health status, especially ex-shift workers.     

Studies on the combined effects of shift work and noise on permanent hearing loss

Combined exposure to shiftwork and noise was investigated with respect to its aural damaging effect. The investigations were carried out on 347 male and female noise-exposed textile workers working in single-shift and three-shift systems. The average hearing loss for the PTS at 3 kHz, 4 kHz, the total hearing loss at 0.5, 1, 2, 4, 6, 8 kHz and percentage of hearing loss according to Fowler/Sabine served as indicators. To fulfil this task an epidemiological cross-sectional study was performed. The results of the present study show lower average hearing loss values in the case of three-shift workers as compared with single-shift workers.     

Leisure-time physical activity levels and changes in relation to risk of hip fracture in men and women.

The authors prospectively studied the effect of leisure-time physical activity level on hip fracture risk along with the influence of within-subject changes in activity levels, while taking possible confounding by other health behaviors and poor health into account. Analyses were based on pooled data from three population studies conducted in Copenhagen, Denmark. Among 13,183 women and 17,045 men, 1,121 first hip fractures were identified during follow-up. In comparison with being sedentary, the relative risk (RR) of hip fracture associated with being moderately physically active 2-4 hours per week was 0.72 (95% confidence interval (CI): 0.59, 0.89) in women and 0.75 (95% CI: 0.55, 1.03) in men after adjustment for confounders. Being in the most active leisure activity category did not decrease the risk of hip fracture further. Adjustment for poor health affected the risk estimates only modestly. Subjects who, during follow-up, reduced their physical activity level from the highest or the intermediate activity level to a sedentary level had a higher risk of hip fracture than did those who remained moderately physically active at the intermediate level (multivariate adjusted RR = 2.19, 95% CI: 1.00, 4.84 and RR = 1.89, 95% CI: 1.21, 2.95, for reduction from the highest and intermediate levels, respectively). There was no evidence of a fracture-protective effect from increasing physical activity. In conclusion, moderate levels of physical activity appear to provide protection against later hip fracture. Decline in the physical activity level over time is an important risk factor for hip fracture.     

Effects of work-related factors and work-family conflict on depression among Japanese working women living with young children

Objective In a Japanese metropolis, we examined the effects of work-related factors and work-family conflict on depressive symptoms among working women living with young children. Methods Data was derived from women (n=501) who lived with at least one preschool child and worked for 20 hours or more per week. As work-related factors, we chose job pressure, skill underutilization, dissatisfaction with personal income, inflexible work schedule, job insecurity, and relationships in the workplace. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. The effects of work-related factors and work-family conflict on depressive symptoms were explored by hierarchical regression analysis. Results Work-related factors except job pressure were significantly correlated with depressive symptoms. Multiple regression analyses revealed that women who had more frequent work-family conflict and more work-related stressors such as bad relationships in the workplace, job insecurity, and underutilization of skills were likely to have more depressive symptoms. Conclusions Among women workers with young children, work-family conflict and various work-related factors such as perceived bad relationships at work, job insecurity, and underutilization of skills had a significant relationship with depressive symptoms. Much more research is needed to explore ways to support working mothers.     

Associations Between Employees’ Work Schedules and the Vocational Consequences of Workplace Injuries

Introduction This study examines the effect of long-hour work schedules and nonstandard shift work (e.g., night and evening shifts) on the ability of injured workers to maintain productive employment following a workplace injury. Methods Analyses were based on 13 years of data from the National Longitudinal Survey of Youth. Multivariate logistic regression analyses were performed with one of ten nonstandard schedules as the independent variable and a particular vocational consequences as the dependent variable. Vocational consequences included being unable to perform normal job duties, temporary job reassignment, working less than full time, filing a workers’ compensation claim, and quitting or being fired because of the injury. Covariates in the regression model included age, gender, occupation, industry, and region. Results The most prominent effects of working a nonstandard schedule were a increased risk of being fired (OR = 1.81; 1.15–2.90 CI 95%), quitting (OR = 1.68; 1.20–2.36 CI 95%), or being unable to work full time (OR = 1.33; 1.08–1.64 CI 95%) following an injury, compared to injured workers in conventional schedules. Schedules involving overtime and long working hours generally had a greater impact on vocational consequences following a workplace injury than did schedules involving night, evening, and other nonstandard shift work. Conclusions Occupational rehabilitation professionals need to consider the specific type of work schedule when developing effective return-to-work plans for injured workers. Special precautions need to be taken for workers returning to schedules that involve more than 12 h per day, 60 h per week, and long commutes.