Estimated sleep debt and work stress in Japanese white-collar workers

Subjective Symptoms Linked to Sleep Duration: An Analysis from Japanese National Statistics

BACKGROUND

There is a high prevalence of sleep disorders in Japan, and they are a factor in a decreased quality of life. The main objective of this study was to clarify the background factors of sleep disorders that affect sleep duration, such as subjective symptoms and working hours.

METHODS

We performed a cross-sectional study on the Japanese national statistics data. Answers from a household questionnaire were used to analyze risk factors for decreases in sleep duration. The subjects were a total of 3972 men and women aged 40-59 years, the age group that forms the core of the working population. For the analysis, a univariate analysis (contingency table) between sleep duration (two groups: sleep duration ≥ 6 h and <6 h) and 42 subjective symptoms was carried out. A multivariate analysis (binomial logistic regression) was conducted using sleep duration and subjective health assessment as objective variables, and odds ratios (ORs) adjusted for sex, working hours, and other factors were obtained.

RESULTS

The univariate analysis by subjective symptom showed significant ORs for eight symptoms, including poor sleep quality (OR: 2.24), constipation (OR: 2.24), and dizziness (OR: 1.77). In the multivariate analysis, the model with sleep duration as the objective variable showed significantly adjusted ORs for four variables, including constipation (1.72) and poor sleep quality (1.66). The model with subjective health assessment as the objective variable showed significantly adjusted ORs for eight variables, including dizziness (4.18), while poor sleep quality (1.45) was not significant.

CONCLUSIONS

The present results suggest the presence of subjective symptoms that may be inferred to be related to decreases in sleep duration.

Changes in work patterns during COVID-19 lockdown and its impact on the eyes and body

CLINICAL RELEVANCE

Greater usage of digital devices and change of work pattern as working from home have created an impact on both visual and musculoskeletal systems. Developing an understanding of these changes could assist in providing appropriate care.

BACKGROUND

The current study aims to elicit the changes in work patterns due to COVID-19 lockdown and understand the impact of the usage of digital devices on the visual system and musculoskeletal system.

METHODS

A survey was designed using Delphi technique and circulated through electronic communication sources using Google form to the working population and students across India, who consented to participate. The survey had components designed to develop an understanding of work patterns, digital device usage, associated visual/ocular symptoms, work-related musculoskeletal disorder (WRMSD) symptoms, and relevant information on psychological factors, and practice of yoga/exercises.

RESULTS

There were 1302 valid responses. Mean age of respondents was 24 (IQR 11) years and 548 (42.1%) were male. A total of 1231 (94.5%) reported having one or many visual and ocular symptoms associated with the use of digital devices and 1140 (87.6%) responses indicated WRMSD symptoms. Of the symptomatic respondents, 561 (43.1%) had reported visual/ocular symptoms and 586 (45%) WRMSD symptoms during lockdown, which they did not experience during regular work. Risk factors for visual/ocular symptoms and WRMSD were females, spending more than 6 h on digital devices, taking breaks from digital devices after 2 h, inability to maintain a fair sleep schedule, and inability to make ergonomic modifications at home.

CONCLUSIONS

A high prevalence of both visual/ocular symptoms (43.1%) and WRMSD symptoms (45%) was encountered during COVID-19 lockdown.

Relationship between long work hours and self-reported sleep disorders of non-shift daytime wage workers in South Korea: data from the 5th Korean Working Conditions Survey

Background

Studies have investigated the relationship between long work hours and sleep disorders; however, they have focused on shift workers or specific workers who are at high risk of industrial accidents rather than wage workers in general. The purpose of this study is to investigate the effects of long work hours on sleep disorders among non-shift daytime wage workers.

Methods

We conducted a secondary analysis of data from the 5th Korean Working Conditions Survey. From the 50,205 total participants, we included 26,522 non-shift daytime wage workers after excluding self-employed people, business owners, unpaid family employees, and wage workers who work nights and shifts. Sleep disorders were categorized into “difficulty in falling asleep,” “frequent waking,” and “waking up with fatigue.” Logistic regression analysis was used to evaluate the influence of long work hours on sleep disorders, and the odds ratios (ORs) were calculated.

Results

The OR of working > 52 hours per week was 1.183 (95% confidence interval [CI]: 1.002–1.394) for the risk of developing insomnia compared with working ≤ 40 hours per week. The OR of waking up with fatigue was 1.531 (95% CI: 1.302–1.801). Long work hours showed no significant relationship with difficulty in falling asleep or with frequent waking.

Conclusions

Working for extended hours was associated with increased fatigue upon waking in non-shift daytime wage workers.

Long working hours and psychiatric treatment: A Danish follow-up study

Objective:

This study aimed to estimate prospective associations between long working hours and (i) redeemed prescriptions for psychotropic drugs and (ii) psychiatric hospital treatment due to mood, anxiety or stress-related disease, among full-time employees in Denmark.

Methods:

Full-time employees who participated in the Danish Labor Force Survey sometime in the period 2000–2013 (N=131 321] were followed for up to five years in national registers for redeemed prescriptions for psychotropic drugs and psychiatric hospital treatment due to mood, anxiety or stress-related disease. Rate ratios (RR) were estimated for 41–48 versus 32–40 and >48 versus 32–40 working hours a week. The analyses were controlled for sex, age, night shift work, calendar time of the interview and socioeconomic status (SES). Prevalent cases were excluded in primary analyses.

Results:

The RR for psychotropic drugs were estimated at 0.94 [99% confidence interval (CI) 0.88–1.01] for 41–48 versus 32–40 working hours a week and 1.08 (99% CI 0.99–1.18) for >48 versus 32–40 working hours a week. The corresponding RR for psychiatric hospital treatments were estimated at 0.90 (95% CI 0.75–1.08) and 0.96 (95% CI 0.76–1.21). We did not find any statistically significant interaction between weekly working hours and age, sex, SES or night shift work.

Conclusion:

Long working hours as they occur in in the general working population of Denmark are not an important predictor of mental ill health.

Prospective Associations Between Working Time Arrangements and Psychiatric Treatment in Denmark: Protocol for a Cohort Study

BACKGROUND

The burden of mental ill health in working-age populations has prompted research on possible links between work-related factors and mental ill health. Long working hours and night shift work are some of the factors that have been studied in relation to the risk of developing mental ill health. Yet, previous studies have not generated conclusive evidence, and further studies of high quality are needed.

OBJECTIVE

This study aims to investigate the prospective association between working time arrangements and mental health in terms of psychotropic drug usage or psychiatric hospital treatment in the general working population of Denmark.

METHODS

Data on total weekly working hours in any job and night shift work from the Danish Labor Force Survey 2000-2013 will be linked to data from the Psychiatric Central Research Register (expected 2400 cases during 700,000 person years at risk) and National Prescription Registry (expected 17,400 cases during 600,000 person years at risk). Participants will be followed for up to 5 years. We will use Poisson regression to separately analyze incidence rates of redeemed prescriptions for psychotropic medicine and incidence rates of psychiatric hospital treatment due to mood disorders, anxiety disorders, or stress-related disorders as a function of weekly working hours and night shift work. The analyses will be controlled for sex, age, calendar time of the interview, and socioeconomic status.

RESULTS

This is a study protocol. Power calculations indicate that the study has sufficient statistical power to detect relatively small differences in risks and minor interactions (eg, ~90% power to detect a rate ratio of 1.1 for psychoactive medication use). We expect the analyses to be completed by the end of 2020 and the results to be published in 2021.

CONCLUSIONS

In this study protocol, all hypotheses and statistical models of the project have been completely defined before we link the exposure data to the outcome data. The results of the project will indicate to what extent and in what direction the national burden of mental ill health in Denmark has been influenced by long working hours and night shift work.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/18236.

Subjective measures of work-related fatigue in automobile factory employees

BACKGROUND

Work-related fatigue is common among automobile factory employees.

OBJECTIVES

The purpose of this study was to assess fatigue of employees at a Chinese automobile factory.

METHODS

238 employees (119 engineers and 119 workers) participated in this study. The following questionnaires were completed: demographic survey questionnaire, working condition questionnaire (WCQ), functional assessment of chronic illness therapy-fatigue (FACIT-F), subscales of multidimensional fatigue inventory (MFI), and Pittsburgh sleep quality index (PSQI).

RESULTS

Both engineers and workers experienced fatigue. The workers (35.6 years old, SD = 6.7) generally felt more fatigue than engineers (42.6 years old, SD = 6.4). The engineers claimed to be more satisfied with the working conditions than workers. The WCQ showed good properties for assessing work-related factors, which were significantly correlated with fatigue (r = 0.568 for engineers and r = 0.639 for workers). For engineers, general fatigue was observed regularly and frequently, and for workers, physical fatigue usually had a long duration.

CONCLUSIONS

The fatigue was significantly correlated with work-related factors, especially working environment and monotony. For workers, the duration of the work day also affected their fatigue. Some improvements to the working condition in this automobile factory should be considered.

Long weekly working hours and ischaemic heart disease: a follow-up study among 145 861 randomly selected workers in Denmark

OBJECTIVES

The aim of the present study was to test if incidences of ischaemic heart disease (IHD) and usage of antihypertensive drugs are independent of weekly working hours (WWH) among full-time employees in Denmark.

DESIGN AND PARTICIPANTS

Data on WWH from participants of the Danish labour force surveys, 1999-2013, were linked on an individual level to national registers with data on socioeconomic status (SES), industry, emigrations, redeemed prescriptions, hospital contacts and deaths. Participants were followed until the end of 2014 (on average 7.7 years). Poisson regression was used to model incidence rates as a function of WWH. The analyses were controlled for calendar time, time passed since start of follow-up, employment in the healthcare industry, age, sex, SES and night work.

RESULTS

In total, we found 3635 cases of IHD and 20 648 cases of antihypertensive drug usage. The rate ratio of IHD was 0.95 (95% CI 0.85 to 1.06) for 41-48 compared with 32-40 WWH and 1.07 (0.94 to 1.21) for >48 compared with 32-40 WWH. The corresponding rate ratios for antihypertensive drug usage were 0.99 (0.95 to 1.04) and 1.02 (0.97 to 1.08). No statistically significant interactions between WWH and sex, SES and night work, respectively, were found.

CONCLUSION

In this Danish sample, we did not find any statistically significant association between WWH and IHD or antihypertensive drug usage.

Long working hours and subsequent use of psychotropic medicine: a study protocol

BACKGROUND

Mental ill health is the most frequent cause of long-term sickness absence and disability retirement in Denmark. Some instances of mental ill health might be due to long working hours. A recent large cross-sectional study of a general working population in Norway found that not only "very much overtime", but also "moderate overtime" (41-48 work hours/week) was significantly associated with increased levels of both anxiety and depression. These findings have not been sufficiently confirmed in longitudinal studies.

OBJECTIVE

The objective of the study is to give a detailed plan for a research project aimed at investigating the possibility of a prospective association between weekly working hours and use of psychotropic medicine in the general working population of Denmark.

METHODS

People from the general working population of Denmark have been surveyed, at various occasions in the time period 1995-2010, and interviewed about their work environment. The present study will link interview data from these surveys to national registers covering all inhabitants of Denmark. The participants will be followed for the first occurrence of redeemed prescriptions for psychotropic medicine. Poisson regression will be used to analyze incidence rates as a function of weekly working hours (32-40; 41-48; > 48 hours/week). The analyses will be controlled for gender, age, sample, shift work, and socioeconomic status. According to our feasibility studies, the statistical power is sufficient and the exposure is stable enough to make the study worth the while.

RESULTS

The publication of the present study protocol ends the design phase of the project. In the next phase, the questionnaire data will be forwarded to Statistics Denmark where they will be linked to data on deaths, migrations, socioeconomic status, and redeemed prescriptions for psychotropic medication. We expect the analysis to be completed by the end of 2014 and the results to be published mid 2015.

CONCLUSIONS

The proposed project will be free from hindsight bias, since all hypotheses and statistical models are completely defined, peer-reviewed, and published before we link the exposure data to the outcome data. The results of the project will indicate to what extent and in what direction the national burden of mental ill health in Denmark has been influenced by long working hours.

Scale-free fluctuations in behavioral performance: delineating changes in spontaneous behavior of humans with induced sleep deficiency

The timing and dynamics of many diverse behaviors of mammals, e.g., patterns of animal foraging or human communication in social networks exhibit complex self-similar properties reproducible over multiple time scales. In this paper, we analyze spontaneous locomotor activity of healthy individuals recorded in two different conditions: during a week of regular sleep and a week of chronic partial sleep deprivation. After separating activity from rest with a pre-defined activity threshold, we have detected distinct statistical features of duration times of these two states. The cumulative distributions of activity periods follow a stretched exponential shape, and remain similar for both control and sleep deprived individuals. In contrast, rest periods, which follow power-law statistics over two orders of magnitude, have significantly distinct distributions for these two groups and the difference emerges already after the first night of shortened sleep. We have found steeper distributions for sleep deprived individuals, which indicates fewer long rest periods and more turbulent behavior. This separation of power-law exponents is the main result of our investigations, and might constitute an objective measure demonstrating the severity of sleep deprivation and the effects of sleep disorders.

Measuring individual vulnerability to sleep loss--the CHICa scale

The aim of this project was to construct a psychometrically satisfying scale to describe subjective reactions to sleep deprivation. First, on the basis of a literature review, a list of items was generated which reflected the negatively affected mood and reduced wellbeing associated with sleep loss. Additionally, psychology students were asked to describe their cognitive and emotional symptoms following a night with curtailed sleep. As a result, 69 items were included in the experimental set. University students (n = 102, females, mean age 22.5 ± 1.9 years) completed the form several times during 1 week in June (while preparing for examinations) and on a free day in September; a total of 460 forms were collected. The final, 26-item version of the scale was validated in a sleep deficit experiment lasting 1 week, conducted with 25 female participants (mean age 23.4 ± 1.9 years). Factor analysis showed 71.7% of total variance explained by four components: impaired thermoregulation (C for cold), disrupted appetite (H for hunger), affective problems (I for irritability) and lowered level of cognitive functioning (Ca for cognitive attenuation). A Polish version of the CHICa scale showed satisfactory psychometric properties. Cronbach's alpha of the subscales were between 0.90 and 0.95. All four subscales exhibited a significant increase with an experimental 3-h daily sleep restriction over a period of 1 week; cognitive attenuation was the most symptomatic. Cognitive problems (reduced concentration, comprehension and accuracy) and a lack of energy seem to be the most specific subjective manifestations of the chronic sleep deficit state. CHICa may be helpful in research on inter-and intra-individual differences and on the efficacy of various counteractive treatments for the consequences of sleep deprivation.

Bedtime and sleep duration in relation to depressive symptoms among Japanese workers

OBJECTIVES

While bedtime may influence circadian rhythms, potentially leading to depression, epidemiological data on this issue are limited. We cross-section-ally investigated the association between bedtime and depressive symptoms in Japanese workers, taking sleep duration into consideration.

METHODS

The participants were 1,197 workers who participated in a health survey during a periodic checkup and had no history of psychiatric disease. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Usual bedtime and wake time were inquired about using a self-administered questionnaire, and sleep duration was calculated based on the difference between these two values. Multiple logistic regression was used to estimate the odds ratio of depressive symptoms for bedtime or sleep duration categories.

RESULTS

Short sleep duration (<6 hours) was significantly associated with an increased prevalence of depressive symptoms. Late bedtime was also significantly associated with an increased prevalence of depressive symptoms (CES-D score of £19); the multi-variable-adjusted odds ratio of depressive symptoms for a bedtime of 1:00 or later versus 23:00 to 23:59 was 1.90 (95% confidence interval, 1.16-3.12). After additional adjustment for sleep duration, however, the association was largely attenuated (odds ratio, 1.17; 95% confidence interval, 0.66-2.06).

CONCLUSIONS

Late bedtime was associated with increased prevalence of depressive symptoms, but this association could be largely accounted for by short sleep duration. Avoiding a late bedtime and obtaining a sufficient sleep duration may prevent depressive mood among workers.

A cross-sectional study of the association between working hours and sleep duration among the Japanese working population

OBJECTIVES

This study aimed to clarify the association between long working hours and short sleep duration among Japanese workers.

METHODS

We selected 4,000 households from across Japan by stratified random sampling and conducted an interview survey of a total of 662 participants (372 men; 290 women) in November 2009. Logistic regression analyses were performed using "sleep duration <6 hours per day" as a dependent variable to examine the association between working hours/overtime hours and short sleep duration.

RESULTS

When male participants who worked for ≥7 but <9 hours per day were used as a reference, the odds ratio (OR) for short sleep duration in those who worked for ≥ 11 hours was 8.62 (95% confidence interval [CI]: 3.94-18.86). With regard to overtime hours among men, when participants without overtime were used as a reference, the OR for those whose period of overtime was ≥ 3 hours but <4 hours was 3.59 (95% CI: 1.42-9.08). For both men and women, those with long weekday working hours tended to have a short sleep duration during weekdays and holidays.

CONCLUSIONS

It is essential to avoid working long hours in order to prevent short sleep duration.

Sleep complaints in middle-aged women and men: the contribution of working conditions and work-family conflicts

This study aimed to examine how physical working conditions, psychosocial working conditions and work-family conflicts are associated with sleep complaints, and whether health behaviours explain these associations. We used pooled postal questionnaire surveys collected in 2001-2002 among 40-60-year-old employees of the City of Helsinki (n = 5819, response rate 66%). Participants were classified as having sleep complaints if they reported sleep complaints at least once a week on average (24% of women and 20% of men). Independent variables included environmental work exposures, physical workload, computer work, Karasek's job strain and work-family conflicts. Age, marital status, occupational class, work arrangements, health behaviours and obesity were adjusted for. Most working conditions were associated strongly with sleep complaints after adjustment for age only. After adjustment for work-family conflicts, the associations somewhat attenuated. Work-family conflicts were also associated strongly with women's [odds ratio (OR) 5.90; confidence interval (CI) 4.16-8.38] and men's sleep (OR 2.56; CI 1.34-4.87). The associations remained robust even after controlling for unhealthy behaviours, obesity, health status, depression and medications. Physically strenuous working conditions, psychosocial job strain and work-family conflicts may increase sleep complaints. Efforts to support employees to cope with psychosocial stress and reach a better balance between paid work and family life might reduce sleep complaints. Sleep complaints need to be taken into account in worksite health promotion and occupational health care in order to reduce the burden of poor sleep.

Job stress factors, stress response, and social support in association with insomnia of Japanese male workers

The aim of the present study was to examine the relation of insomnia with job stress factors, stress response, and social support. A self-completed questionnaire survey was conducted in 212 male Japanese workers at a synthetic fiber plant. With regard to insomnia, subjects were asked the first 5 of the 8 questions on the Athens Insomnia Scale (AIS). Job stress factors, stress response and social support were assessed using the Job Stress Questionnaire. Multiple regression analyses showed that psychological job stress factors of poor appropriateness of work and high qualitative workload were associated with insomnia. The psychological stress response of depression and physical stress responses were also related with insomnia. Depression was also related to appropriateness of work. The present results showed that insomnia was closely related with the psychological job stress factor of appropriateness of work and the psychological response of depression. These mutual relationships between insomnia and poor mental health need be investigated further.

Fatigue and Mood Correlates of Sleep Length in Three Age‐Social Groups: School Children, Students, and Employees

The aim of the study was to trace the consequences of insufficient sleep, in terms of chronic sleep reduction rather than acute sleep deprivation, on fatigue, mood, cognitive performance self-estimations, and daytime sleepiness in different age-social groups. The age group of the subjects reflects their social situation and their working time organization: adolescents (n = 191) obeyed the strict school schedules with starting times often before 08:00 h; university students (n = 115) had more flexible timetables; young employees (n = 126) were engaged in regular morning schedules or irregular daytime hours or day and night shifts. A questionnaire study determined the declared need of sleep, self-reported sleep length, chronic fatigue (using a scale comprised of eight fatigue symptoms and four mood and three cognitive items), and daytime sleepiness (Epworth Sleepiness Scale). The declared need for sleep decreased in subsequent age groups from 9 h 23 min in school children to 8 h 22 min in university students and to 7 h 37 min in young employees. Consequently, the discrepancy between preferred and real sleep length (sleep deficit) was the largest in adolescents: 106 min. Females showed a greater need of sleep than males (p = .025) and significantly more fatigue, mood, and cognitive problems; they also exhibited higher level of daytime sleepiness (p < .000). The sleep index (reported sleep length related to requirements) correlated significantly with all health issues in women (p < .000), while only with fatigue symptoms in men (p = .013). Actual sleep length was unrelated to mood and fatigue issues; the declared individual need of sleep and sleep index showed significant associations, especially in the group of adolescents. The most frequent complaints of adolescents included tiredness on awakening (46%), nervousness, and general weakness; university students reported excessive drowsiness (50%), tension, and nervousness; employees suffered mostly from negative moods, such as tension (49%), nervousness, and irritability. The findings of the study indicate that chronic sleep loss seems to affect females more severely than males. The associations of fatigue and mood with sleep need and sleep index were more pronounced in younger subjects. Surprisingly, fatigue symptoms in school children and university students were as frequent as in hard-working adults. Because the problem of insufficient sleep is already present in youngsters, their work time organization needs more attention.

Long working hours and sleep disturbances: the Whitehall II prospective cohort study

STUDY OBJECTIVE

To examine whether exposure to long working hours predicts various forms of sleep disturbance; short sleep, difficulty falling asleep, frequent waking, early waking and waking without feeling refreshed.

DESIGN

Prospective study with 2 measurements of working hours (phase 3, 1991-1994 and phase 5, 1997-1999) and 2 measurements of subjective sleep disturbances (phase 5 and phase 7, 2002-2004).

SETTING

The Whitehall II study of British civil servants.

PARTICIPANTS

Full time workers free of sleep disturbances at phase 5 and employed at phases 5 and 7 (n = 937-1594) or at phases 3, 5, and 7 (n = 886-1510).

MEASUREMENTS AND RESULTS

Working more than 55 hours a week, compared with working 35-40 hours a week, was related to incident sleep disturbances; demographics-adjusted odds ratio (95% CI) 1.98 (1.05, 3.76) for shortened sleeping hours, 3.68 (1.58, 8.58) for difficulty falling asleep; and 1.98 (1.04, 3.77) for waking without feeling refreshed. Repeat exposure to long working hours was associated with odds ratio 3.24 (1.45, 7.27) for shortened sleep, 6.66 (2.64, 16.83) for difficulty falling asleep, and 2.23 (1.16, 4.31) for early morning awakenings. Some associations were attenuated after adjustment for other risk factors. To a great extent, similar results were obtained using working hours as a continuous variable. Imputation of missing values supported the findings on shortened sleep and difficulty in falling asleep.

CONCLUSION

Working long hours appears to be a risk factor for the development of shortened sleeping hours and difficulty falling asleep.

[Relationship between employees' management factor of visual display terminal (VDT) work time and 28-item General Health Questionnaire (GHQ-28) at one Japanese IT company's computer worksite]

OBJECTIVES

We studied 1365 male workers at a Japanese computer worksite in 2004 to determine the relationship between employees' time management factor of visual display terminal (VDT) work and General Health Questionnaire (GHQ) score.

METHODS

We developed questionnaires concerning age, management factor of VDT work time (total daily VDT work time, duration of continuous work), other work-related conditions (commuting time, job rank, type of job, hours of monthly overtime), lifestyle (smoking, alcohol consumption, exercise, having breakfast, sleeping hours), and the Japanese version of 28-item General Health Questionnaire (GHQ). Multivariate logistic regression analyses were performed to estimate the odds ratios (ORs) of the high-GHQ groups (>6.0) associated with age and the time management factor of VDT work.

RESULTS

Multivariate logistic regression analyses indicated lower ORs for certain groups: workers older than 50 years old had significantly a lower OR than those younger than 30 years old; workers sleeping less than 6 h showed a lower OR than those sleeping more than 6 h. In contrast, significantly higher ORs were shown for workers with continuous work durations of more than 3 h compared with those with less than 1 h, those with more than 25 h/mo overtime compared with those with less, those doing VDT work of more than 7.5 h/day compared with those doing less than 4.5 h/day, and those with more than 25 h/mo of overtime compared with those with less.

CONCLUSION

Male Japanese computer workers' GHQ scores are significantly associated with time management factors of VDT work.

An Investigation of the Role of Non–Work-Time Behavior in Buffering the Effects of Work Strain

OBJECTIVE

In this exploratory study, we investigated the extent to which common leisure time behaviors, which generate positive feelings of fulfillment and personal reward, are significant in alleviating work-induced stress between successive work periods. We tested the hypotheses that such activities increase recovery from stress directly, and also by improving sleep quality, thereby alleviating maladaptive outcomes from work strain.

METHOD

An on-line survey study was completed by a heterogeneous sample of 314 workers in diverse occupations, in good health.

RESULTS

Non-work-time behaviors play a significant role in mediating maladaptive outcomes from work strain. Multivariate analysis of these relationships indicates both direct and indirect effects, the latter being associated with mediating sleep quality. Respondents reporting higher levels of active leisure activities, exercise, and creative (hobby) and social activity, reported significantly better sleep, recovery between work periods, and lower chronic maladaptive fatigue symptomology.

CONCLUSION

Active and fulfilling non-work-time behaviors are more significant in maximizing recovery from work strain than is commonly recognized. This effect is arguably due to the downregulation of stress-induced brain arousal, and stimulation of the pleasure-reward brain neurophysiology. Consistent recovery from work strain between work periods may represent a crucial factor in avoiding work-related "loss spirals" leading to maladaptive health outcomes, which can be particularly relevant to workers in inherently stressful occupations.

Possible broad impacts of long work hours

The paper summarizes research linking long work hours to a wide range of risks to workers, families, employers, and the community. The risks are theorized to stem from less time to recover from work, longer exposure to workplace hazards, and less time to attend to non-work responsibilities. Risks to workers include sleep deprivation, poor recovery from work, decrements in neuro-cognitive and physiological functioning, illnesses, adverse reproductive outcomes, and injuries. Risks to families include delayed marriages and child bearing, and obesity in children. Risks to employers include reduced productivity and increases in workers errors. Mistakes by fatigued workers have broad reaching impacts to the community: medical errors, automobile crashes with other drivers on the road, and industrial disasters that damage the environment.

Influence of overtime work, sleep duration, and perceived job characteristics on the physical and mental status of software engineers

To investigate the impact of overtime work, sleep duration, and perceived job characteristics on physical and mental status, a cross-sectional study was conducted on 377 workers (average age; 28 years old) in an information-technology (IT) company, engaged in consultation, system integration solution, and data management relevant to IT system. The psychophysical outcomes of overtime work were assessed using the Hamilton Depression Scale (HDS), Profile of Mood Status (POMS), major physical symptoms, and overtime work data for the preceding three-months. Sleep duration was directly asked by a physician. A job strain index was defined as the ratio of job-demands to job-control scores evaluated using the Job Content Questionnaire (JCQ). In a univariate analysis, overtime work was significantly related with HDS scores, POMS anger-hostility scores, and the total physical symptom count in both sexes (all p < 0.05), but not in multiple regression models, after controlling for sleep duration and the job strain index. Sleep duration was negatively related to the symptom count in men and to POMS tension-anxiety scores in women (both p < 0.05); the job strain index was positively related to POMS anger-hostility scores in both sexes and to HDS scores and POMS tension-anxiety scores in men (all p < 0.05). Although overtime work was associated with physical and mental complaints, sleep duration and the job strain index seemed to be better indicators for physical and mental distress in overloaded workers.

Development and Validation of a Scale to Measure Work-Related Fatigue and Recovery: The Occupational Fatigue Exhaustion/Recovery Scale (OFER)

OBJECTIVE

Various empirical studies link persistent failure to recover from acute fatigue to the evolution of chronic fatigue. However, existing fatigue measurement scales do not tend to distinguish between acute and chronic fatigue elements well, and none include a measure of effective recovery from fatigue.

METHODS

The 15 item Occupational Fatigue Exhaustion Recovery (OFER) scale has been developed and validated in three study populations specifically to measure work-related fatigue.

RESULTS

The OFER scale possesses robust, gender-bias free psychometric characteristics. Its three subscales identify and distinguish between chronic work-related fatigue traits, acute end-of-shift states and effective fatigue recovery between shifts.

CONCLUSION

These studies confirm the mediating role of intershift-shift recovery in the evolution of adaptive end-of-shift fatigue states to maladaptive persistent fatigue traits. The OFER scale is suggested as a potentially valuable new tool for use in work-related fatigue research.

Associations of sleep problems and recent life events with smoking behaviors among female staff nurses in Japanese hospitals

For the purpose of examining the relation of sleep problems and other possible correlates with smoking among staff nurses in hospitals, the cross-sectional data of a self-administered questionnaire survey for 522 Japanese female staff nurses were reanalyzed. Registered nurses or licensed practical nurses were 82%, while nursing assistants were 18%. The prevalence of current smoking (PCS) was 29%, being higher than that in the general population of Japanese women. The current smokers exhibited a high tendency toward tobacco dependence. Multivariate analyses revealed that PCS was associated with recent frequent night shifts and a large amount of support from coworkers, while the association of a large amount of job control and a feeling of light overnight sleep with PCS was also suggested. The tobacco-dependent tendency was associated with recent life events and the presence of insomnia. It is possible that smoking is a countermeasure against sleepiness caused by the disadaptation to shift-work, or that tobacco-intake pharmacologically disturbs sleep. For decreasing PCS in staff nurses, further research should focus on the relation of smoking with their sleepiness and shift-working system, and also on the process in which major life events develop smoking behaviors.

An epidemiologic review on occupational sleep research among Japanese workers

Epidemiologic sleep research on Japanese workers has been increasing in recent years. It is timely to give an overview of the sleep issues facing the Japanese working population by reviewing the accumulated epidemiological evidence, which will contribute to the promotion of a sound occupational health policy and the development of occupational sleep research in epidemiology. This paper reviews 24 studies, 13 for non-shift and 11 for shift Japanese workers, identified by using MEDLINE and Japan Cetra Revuo Medicina. The results reviewed are as follows: 1) the prevalence of insomnia and other sleep problems is substantially varied, 5 to 45% for non-shift and 29 to 38% for shift workers, 2) poor sleep quality is related to health, occupational activities and personal relations, 3) the risk or associated factors are identified in pathophysiology (e.g., hypertension), lifestyle behaviors (e.g., diet, alcohol, tobacco), job-related conditions (e.g., job stress, social support, job dissatisfaction, workload, shift schedules) and psychopathology (e.g., depressed mood). The methodological limitations found in the studies and the strategies of future epidemiologic sleep research in workers are discussed.

[Development of the Brief Scales for Coping Profile (BSCP) for workers: basic information about its reliability and validity]

Coping profile of workers greatly affects the process where job stressors develop health problems, but most of the previously proposed questionnaires for the coping profile are too long to be applied to the program of occupational mental health. In the present study, the authors report the process of developing a new self-rating questionnaire for assessing workers' coping profile which includes only 18 questions. Based on the results of a preparatory study, the 18 questions which provide 6 scales about coping strategies were proposed as the Brief Scales for Coping Profile (BSCP). A self-administered questionnaire including BSCP, Brief Scales for Job Stress (BSJS), and a depression scale (CES-D) was applied to 394 workers in a company, and 328 (83%) responded. Their age was 40.1 +/- 10.0 yr (mean +/- SD), 78% were men, 75% were married, and most of them were white collar workers. Six factors extracted through factor analysis of BSCP closely agreed with the expected 6 scales and also with the results of previous studies. They were named "active solution", "seeking help for solution", "changing a point of view", "changing mood", "emotional expression involving others", and "avoidance and suppression". The Cronbach's reliability coefficients for the scales were from 0.66 to 0.75, showing sufficiently high internal consistency. None of them related to gender or age. Multiple regression analysis revealed that 38% of the variance of the depression score was explained by "workload", "problems in personal relationships", and "reward from work" scores in BSJS, and also with "active solution" and "avoidance and suppression" scores in BSCP. Interaction analysis revealed that the coping profile modifies the relationship between job stressors and depressive symptoms; the "active solution" score was inversely associated with the depression score, particularly for the workers with high "problems in personal relationships" scores and low "reward from work" scores, while "avoidance and suppression" scores were positively associated with the depression score particularly for the workers with high "problems in personal relationships" scores. These results support part of the reliability and validity of BSCP, and also support the feasibility of BSCP as a tool for self-management and health education concerning job stress in the field of occupational mental health. The test-retest reliability and concurrent validity of BSCP should be confirmed in a future study. It also should be confirmed in future whether the coping profile relates with gender, age, job type, or other outcome of job stress in other populations.

Gender differences in excessive daytime sleepiness among Japanese workers

Excessive daytime sleepiness (EDS) is serious concern in the workplace with respect to errors, accidents, absenteeism, reduced productivity and impaired personal or professional life. Previous community studies found a female preponderance of EDS, however, there is little research on EDS and gender in occupational settings. We examined the gender differences in prevalence and risk factors of EDS among employees working at a telecommunications company in the Tokyo metropolitan area. Our outcome measure of EDS was the Epworth Sleepiness Scale (ESS). A self-administered questionnaire on health and sleep including ESS was distributed to 5,571 workers between December 1999 and January 2000, and 5,072 responses were returned (91.0%). A total of 4,722 full-time, non-manual and non-shift employees aged 20-59 were used for analysis (3,909 men and 813 women). Chi-squared tests and multiple logistic regression analyses were applied for examining the gender differences in the prevalence and risk factors of EDS. The prevalence rates of EDS were 13.3% for women and 7.2% for men (P<0.001). We identified that deprived nocturnal sleep, an irregular sleep-wake schedule and depression were the risk factors of EDS for both genders, and being married worked as a protective factor against EDS for men alone. It is obvious that a ban on overtime work and a provision of mental health hygiene are the general strategies for reducing EDS at worksites. In the case of women, we suggest the formation of effective strategies for improving women's status at home and in the workplace must also be a solution for the prevention of EDS (e.g. promoting gender equality in the division of labor at home and strengthening family care policies for working women).