Toyoshima et al, Health Promotion Perspectives, 2020, 11(1), 87-96
doi: 10.34172/hpp.2021.12

TUOMS
PRESS

https://hpp.tbzmed.ac.ir

Original Article

Understanding the process for developing sleep disorders among
Japanese workers: a qualitative study
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Ayako Toyoshima , Michiko Moriyama , Hidehisa Yamashita, Md Moshiur Rahman* , KATM Ehsanul Huq , Yasmin
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Jahan , Kana Kazawa
Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan

ARTICLE INFO
Article History:
Received: 27 June 2020
Accepted: 4 Nov. 2020
ePublished: 7 Feb. 2021
Keywords:
Sleep disorders, Workers,
Psychosocial factors,
Occupational health*Corresponding Author:
Md Moshiur Rahman,
Email: moshiur@hiroshima-u.
ac.jp

Abstract
Background: Sleep disorders have an enormous impact on occupational health and arecounterproductive from an economic perspective. However, the processes of causing sleep
disorders from psychosocial aspects have not yet been known. The purpose of this study was
to describe how sleep disorders develop among workers with respect to different psychosocial
conditions.
Methods: A conventional qualitative content analysis was conducted with a semi-structured
interview among twenty-seven workers (14 males and 13 females) who were diagnosed withsleep disorders or had a self-reported history of sleep difficulties. Study participants wererecruited from a specialized clinic and communities using snowball sampling. This paper
adhered to the Standards for Reporting Qualitative Research (SRQR) checklist.
Results: The results showed that there were four steps involved in the sleep disorders
development process. Firstly, participants with sleep disorders developed ‘early warning signs’
with 11 categories of triggers; secondly, ‘aggravating factors’ on top of these early warning
signs; thirdly, workers tried to ‘cope with’ their sleep disorders in the ways they thought would
be effective. Finally, when coping failed to improve the quality of sleep, it led to the onset ofsleep disorders.
Conclusion: The development of sleep disorders and triggers of psychosocial factors wererevealed. An occupational health nurse can bring these findings in practice for preventing
worker’s sleep disorders.

Introduction
The global prevalence of sleep disorders was recorded
from countries ranging from 1.6% to 56.0%.1 Sleep
disorders have been associated with reduced working
performance,2 negative physical and mental healthoutcomes and increased incidence of adverse safety
outcomes.3 Among the Organization for Economic Cooperation and Development (OECD) countries, economic
loss due to sleep disorders is estimated to be between 1.4
to 2.3% of the gross domestic product (GDP).4 For thesereasons, sleep disorders are considered as an important
issue in occupational health.
Several occupational factors are known to interferewith sleep. Studies reported the main factors such as
shift work, rest-duration, loneliness, workplace violence,
psychosocial stress,5 poor discretionary power over theirown work hours,6 and harassment7 were altering thequantity and quality of sleep and the consequences, andsuggested health promotion measures.5-7
In Japan, particularly long working hours,8 highconsumption of alcohol, and the shortest sleep time

among 10 countries have been reported the increase inhigher health risk of workers including sleep disorders.9
A cohort study among Japanese employees from various
occupations notified that there was an association
between workaholism and poor sleep quality in terms of
sleep latency and daytime dysfunction.10
Even though health professionals in occupational healthsettings have highlighted the importance of providing
information about sleep,11,12 specific guidelines on how toprevent sleep disorders among workers are yet to be fully
developed. A combination of various practices and habitsof sleep hygiene is essential to ensure the quality of a goodnight’s sleep and full daytime attentiveness.13 Workplacebased employees’ health interventions also suggested
yoga, physical activities and cognitive-behavioral therapy
for insomnia interventions.14 However, until now, sleep
hygiene is the major intervention at a workplace for the
management of sleep disorders.15
Moreover, we can easily understand that there areseveral factors other than occupational environment
affecting sleep disorders such as personal issues of© 2021 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (http://
creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original
work is properly cited.

Toyoshima et alfamily and human relationships. Balancing childbearing,housework, and caregiving along with work are known asstressful situations worldwide.16 Japan is ranked as one of
the lowest countries in terms of home-task sharing.17
Occupational health nursing is responsible for theprevention of diseases related to the work environment
and to promote employees’ health.18 It also can help
employees solve the problems affecting their sleep
disorders, when the distinctive physical, psychosocial,and environmental situations are specified. In fact,
there has been no qualitative discussion on how sleep
disorders develop among workers. If different situations
under which workers suffering from sleep disorders were
described, it might help to establish strategic ways forpreventing these sleep disorders from developing in theoccupational health field. The processes of developing
sleep disorders from psycho-social aspects have not yet
been known. Therefore, it is necessary to figure out thosefactors and timings of prevention. The purpose of thisstudy was to explore the process of developing the sleep
disorders among the Japanese workers and to identify
various factors behind these disorders.

further information was needed. To maintain privacy, theinterviews were conducted in a clinic or in an independent
PR’s office. Researchers stopped recruiting participants
when all the different patterns of sleep disorders
among patients [reference related to the internationalclassification of sleep disorders-3 (ICSD-3)] and all causesof their sleep difficulties were saturated.
A total of 27 participants (14 males and 13 females; age
between 20 to 60 years) were recruited from the hospitaland the communities. The pattern of sleep disorders
among the participants was explained in Table 1.

Materials and Methods
Study design and study setting
Between September and December 2015, we carried out
a conventional qualitative content analysis with a semistructured interview to investigate sleep disorders among
the Japanese workers in Hiroshima city, Japan. This
study adhered to the Standards for Reporting Qualitative
Research (SRQR, Appendix 1).19 The present qualitative
study was designed to identify the important andappropriate research questions focused on revealing thewho (Japanese workers), what (sleep disorders), why, andhow they developed sleep disorders, and receiving insightsfrom informants regarding an unclear phenomenon.
Participants and procedures
Participants were full-and part-time workers, selfemployed or employed by private/public organizations,aged ≥20 years. The inclusion criteria for participants
were having a diagnosis and receiving treatment for sleep
disorders, or a self-reported history of sleep difficulties.
Students and the unemployed were excluded from thisstudy.
Participants were recruited from a specialized hospital
outpatient clinic and communities. In the hospital, thepsychiatrist in charge of sleep disorders introduced theparticipants to the first author [the principal researcher(PR)] who was a nursing graduate student specializedin occupational health. In the communities, a snowball
sampling method was used20 in which the PR found two
informants who met the inclusion criteria and asked themto introduce other workers through their networks. The
PR conducted individual face-to-face in-depth and semistructured interviews lasting approximately 60 minutes,
and these were conducted either once or twice when
88

Health Promot Perspect, 2021, Volume 11, Issue 1

Data collection tool
Participants were asked to reflect on the experience of
their sleep disorders. They were asked to answer thefollowing questions: (1) How did you perceive yourphysical and mental health when you began to have a
Table 1. Characteristics of participants
Age
Gender Occupation/Job type
category

Types of sleep disorders

40's

Male

Office work

Insomnia

50's

Male

Office work

Insomnia

40's

Male

Factory work

Insomnia

60's

FemaleNurse (no shift work)

Insomnia

60's

FemaleElementary school teacher

Insomnia

40's

Male

Agriculture

Insomnia

60's

FemaleDelivery work

Central hypersomnia

40's

Male

Office work

Insomnia

60's

Male

Office work

Parasomnias

40's

Male

Office work

Insomnia

50's

Male

Technologist

Insomnia, sleep apnea
syndrome

30's

FemaleOffice work

Central hypersomnia

30'sFemaleNurse (no shift work)

Insomnia

50's

FemaleUniversity faculty

Insomnia

30's

FemaleNurse (no shift work)

Insomnia, sleep related
movement disorders

60's

Male

Office work

Insomnia

30's

FemaleNurse (no shift work)

Insomnia, circadianrhythm disorder

40's

Male

Office work

Insomnia

40's

Male

Manager

Insomnia

40's

FemaleNurse (no shift work)

Insomnia, sleep apnea
syndrome

40's

FemaleProfessional

Insomnia

30's

FemaleNurse (shift work)

Insomnia

50's

Male

Technician

Insomnia

20'sFemaleNurse (childcare leave)

Insomnia

60's

FemaleHigh school teacher

Insomnia

60's

Male

Office work

Sleep apnea syndrome

50's

Male

Medical technician (withnight shift)

Sleep apnea syndrome,
sleep related movement
disordersToyoshima et al

trouble in sleeping? (2) How was your social situation atthat time? (3) Did you have any subjective symptoms? If
your answer is ‘yes’, what were the symptoms and what
were they like? (4) Did your sleeping difficulties affectyour business? If your answer is ‘yes’, how did it affect yourbusiness? If your answer is ‘no’, please tell us how you wereable to manage your business without being affected byyour sleep disorders. (5) Why and how did you cope withsleeping difficulties?
Participants’ characteristics such as gender, age,occupation, past medical history, and current medical
condition were also collected. A digital voice recorder wasused to record the interviews after obtaining consent fromthe participants.
Data analysis
The principal researcher performed a conventional content
analysis for this study. (1) The contents of the interviews
were documented and used for analysis. The analysis
findings were extracted, and categorized responses related
to the sleep disorders development process, (2) the reasonsfor developing or not developing a coping behavior, and(3) assessed the impact of sleep disorders had on work.
We used ICSD-321 to categorize major sleep disorders
such as insomnia, sleep-related breathing disorders,
central disorders of hypersomnolence, circadian rhythm
sleep-wake disorders, parasomnias, sleep-related
movement disorders, and other sleep disorders. Whenthe participants in the community had no diagnosis by aspecialist, on the basis of the Algorithm for the Evaluationof Chronic Insomnia,22 we evaluated the conditions of thepatients’ sleep disorders. We asked the participants about
their sleep-wake timing patterns, snoring, and restlessleg symptoms, etc., and categorized these patterns for the
purpose of our study.
Ensuring trustworthiness and credibility
All the data were carefully analyzed on the meaning of
the contents, were coded, and categorized by researchers
who specialize in occupational health, chronic care andqualitative analysis. In addition, collaborators who werepsychiatric specialists and sleep experts at the hospitalconfirmed the validity of the analysis contents. Data werealso checked by the research participants, and they wererequested to confirm the consistency and credibility of thecontents.
Results
Process of sleep disorders development
Participants were requested to state what they thought
triggered the development of their sleep disorders andwhat they did to overcome it. Four steps were generated
for developing sleep disorders. First, they developed ‘early
warning signs’ before starting to experience sleeping
difficulties. Secondly, ‘aggravating factors’ were added tothese ‘early warning signs’. Thirdly, workers tried to ‘copewith’ sleeping difficulties. Lastly, when the coping strategy

failed to resolve their sleep difficulties, this led to the onset(‘impact on work’) of their sleep disorders. However, they
did not develop a sleep disorder when the coping strategy
was effective because it made them sleep well (Figure 1).
Early warning signs
The main category (phase) of ‘early warning signs’
was generated and consisted of 11 categories and 27
subcategories (Table 2).
Early warning signs, which were triggering factors,
consisted of physical, psychosocial, and environmental,
behavioral, and combined factors along with holding
excessive beliefs about sleep that the participants wereexperiencing or had developed before they began
experiencing sleep deterioration or deprivation.
The categories include: (1) ‘Insufficient sleeping hours
due to work environment’ and (2) ‘Lack of support
resources’. Physical and environmental factors symbolize
work culture in Japan characterized by long-commuting
distance, long working hours, and the custom of drinking
alcohol after work, leading to a lack of sleep. A participant
mentioned, “Every day, I work until 1am or 2am. If I can goback on the last train, I am lucky. It is the same for everybody.”
Another person explained, “On weekends, I have to attend
my children’s events and housework that cannot be done on
weekdays. My husband just orders me. My parents’ home isfar, I cannot ask for help.” Lack of support was often related
to a lack of workload management. At home, genderbeliefs regarding housework, and long working hours at
the company and side jobs, due to economic conditions
had an influence on this. (3) ‘Jet lag and social jet lag’is physically produced circadian rhythm imbalance byworkers’ frequent overseas business trips, shiftwork, andwide differences between workdays and off days sleepingtime.
(4) ‘Disease symptoms’ such as uncontrolled itchinessand (5) ‘Pregnancy/Breast feeding’ as a physical factor thatdeprived them of a good night’s sleep. (6) ‘Caregiving’ and(7) ‘Ill family members’ were physical and psychologicalfactors that also disturbed sleep. A participant stated,“My father-in-law hurt me by bad words. I struggle, should
I take care of him? It sticks my heart and cannot sleep.”
Another participant spoke, “After my father’s health got
worse, I was worried whether he was alive at night, so I
woke up and went to check on him many times. It lasted formonths.” Caregiving at home generates a physical burden
and can cause conflict with the carer. Negative emotions
such as anger and worry often disturb their sleep over a

Figure 1. Process of developing sleep disorders

Health Promot Perspect, 2021, Volume 11, Issue 1

89Toyoshima et al
Table 2. Onset of early warning signs for sleep disorders
Category

Subcategory

CodeLong hours labor

Workplace habits of working until midnight
Insufficient sleeping hours
due to work environment

Lack of support resources

Working environment to work until midnight
Unable to finish work duty within working hours

Long commuting hours

Commuting time reduces sleeping time

Workplace with habit of drinking and eating out
after work

Drinking and eating out after work leads to going home later

Poor surrounding support resources
Overseas business trip

Workplace drinking party customs
No one to help with the job and consult sleep difficulties in the workplace
No one to help with housework and childcare
Using sleeping pills to adjust to the time difference when traveling abroadNight work

Jet lag and social jet lag

Shift work or time difference work

Inconsistent waking time because the schedule depends on the workload
Sleeping on weekends

Disease symptoms

Pregnancy/Breast feeding

Caregiving

Ill Family members

Uncontrolled symptoms
Breast feeding

Delayed sleep-phase due to sleeping in
Uncontrollable symptoms such as itchiness by atopic dermatitis, pain, coughdue to asthma
Children crying throughout the night
Breast feeding at night
Morning sickness

Physical and Mental fatigue

Worries about family members with dementia wandering around and often
need to go and find her/him
Frequent trips to the toilet during the night

Conflict with a carer

A carer throws/shouts unpleasant words. Cannot allow it.

Beliefs about use of social resources

Taking care of family member is family’s task. Cannot ask for help. Use ofsocial resources is not accepted.

Prolonged anxiety and nervousness (tension) for
anticipating changes in family’s situation

Anger, inferiority complex for families
Families conflict

Worried about whether the family is alive
Nervousness due to unstable family condition (take care of the family at
bedside, and so nervous)
Anxiety about living after family dies
Inferiority complex that a family business cannot be inherited
Loneliness in the home, suppression of anger

The pace of my life is disturbed by adjusting time
to fit in with the lives of others

Always adjusted my time to family time

Keeping complaints inside/unable to solve
problems directly

Too much stress at work/human relationships, but cannot tell anybody,cannot ask for help/ cannot resolve the problem

Unfinished business

Unfinished developmental tasks Unmarried / pregnancy age limit

Bad handling of emotions

Cannot handle emotions well. Anger and complaints inside.

Excessive commitment to sleeping time
Misbelief about sleep

Weekends used to catch up on sleep missed on weekdays

Pregnancy

Anticipatory grief

Personal conflict

Do not know how to adjust one’s biorhythms during night shift

Commitment to bedtime routine
Commitment to total sleeping hours

Obsession/misunderstanding about their sleep
pattern

Cannot sleep well since a child. I am a bad sleeper. It takes a long time forme to fall asleep.

Wrong knowledge about sleep

Once missed the chance to fall asleep, cannot sleep anymore.
Thinking deeply in bed

Thinking in bed

Reflecting on the day in bed and arranging tomorrow’s business. Also, deep
regrets about the day and cannot sleep.
Internet, smart phone in bed

Habits of behavior

Coping behavior to relief stress

Drinking alcohol before bedtime
Eating late at night and before bedtime

90

Exposure to information until just before bedtime

Checking the latest information on the bed

Difference of sleep pressure peak and living
conditions

Allowing them to sleep when they most want to sleep (Sleep in daytime/ rightafter coming home/ after dinner, so cannot sleep at night).

Health Promot Perspect, 2021, Volume 11, Issue 1

Toyoshima et allong period of time. (8) ‘Family conflict’ and (9) ‘Personal
conflict’ were psychological factors displaying negative
feelings towards family member(s) and/or his/herself
and were difficult to control. A participant stated, “I was
always told to take over the family business, but I did nothave the qualification. I always suffered from an inferiority
complex.” Another participant mentioned, “My child cameback to my house with her children. Younger ones have theirown time. I got to sleep late at night too, but I have to wakeup first and wake everyone up.” We observed the feelingof inferiority complex among family member(s), worries
concerning unfinished business, an uncontrollable timeschedule for family members and feeling of anger. The
presence of long-term personal conflict also deprived
them of sleep.
Stereotypes regarding sleeping time and false knowledgeof drowsiness were categorized as (10) ‘Misbeliefs about
sleep’. Some participants obsessively attached highimportance to their bedtime routine, i.e. “I am a person
who cannot sleep before 12 midnight.” “I need 7 hours sleep,
but when I couldn’t then I really get upset.” As a behavioral
factor, (11) ‘Habits of behavior’ were extracted. This
includes thinking about or checking the Internet in bed,
drinking alcohol before bed, sleeping during the daytime,and so forth.
Nobody stated about their physical environment such as
noise, lightning, temperature, bed or mattress, which was
related to the exacerbation.
Aggravating factors
An aggravating factor is another main category generated
from the interviews. As early warning signs were notresolved and persisted, several factors have been attributed
to as factors aggravating sleep conditions. From 19
subcategories, 8 categories were generated. They included(1) ‘Accumulation of fatigue’ in which people continued tosleep for short hours, a hyperactive condition continued,
and some reported a drop in their physical strength. (2)‘Feeling of urgency’ comes from continuous intensive
work and upset them. (3) ‘Crisis of social survival’ iswhen they felt fear of losing their position and caught up
in feelings of defeat amid the competitive environment
at work. (4) ‘Life events and loss’ included loss of family
members, someone close to the participant, familiar
workplace, work position, and meaning of work. (5)‘Changes in work’ refers to changes in working shifts
and being unable to adjust to new tasks. (4) or (5) could
be a trigger itself, but in this intervention these factors
appeared after the warning signs. (6) ‘Guilt for absence’refers to increased feeling of guilt because they needed to
be absent due to their physical condition. (7) ‘Aggravationof physical condition’ is an aggravation of tachycardia;
these physical conditions made their concerns worse. (8)‘Economical anxiety’ results from a combination of age,
single status (being unmarried), health conditions, and an
obsessive for survival, all escalating their anxiety.
The balance between physical ability and amount ofwork became worse because of a decline in physical ability
and insufficient sleeping time to recover from fatigue. The
participants felt pressured in the workplace and at homefrom deadlines or when responding to emergencies. Thesefeelings aggravated their sleeping difficulties.
They became worried that they would lose their job,
and they had an inferiority complex with colleagues or
worried that they might lose their role at the workplacebecause of their low performance evaluation. This leads toinsomnia as they have difficulty adapting to the changes
in new context or different working hours. In particular,
bereavement and change of workplace make them more
vulnerable and cause grief as they feel loneliness andseparated from their family.
Coping strategies
The third main category generated from the interviewsis ‘coping strategies’. It consisted of 2 categories i.e. (1)‘getting support for solving their problems’, which includes
support from private such as family and friends, andofficial services such as harassment consultation, nursing
services, and medical support. (2) ‘Personal efforts for
self-care’, which includes taking sleep aid supplement,
relaxation, maintaining sleep hygiene behavior, andlifestyle changes. Some participants did not ask for help
because of reluctance to visit a psychiatry clinic, taking
medication, fear of retaliation after appealing to public
services, and obsessive thoughts about mother/caregiverand being unable to request for aid.
Impact on work
The fourth main category generated from the interviews
is ‘impact on work’ as a result of all processes. The
consequences of sleep disorders on work were categorized
into two; one was the ‘negative impact on work’, and theother one was the ‘able to do routine work’ with no impact
on work. In the negative impact, participants reported
that insomnia symptoms such as declining concentration
or strong drowsiness had a negative impacted on
their business. On the other hand, some could do theroutine work despite having insomnia symptoms. They
felt they could do their job without making mistakes
or causing troubles when they did the routine work.
Sleep disorders other than insomnia and circadian rhythm
disorders
In this study, sleep apnea, central hypersomnia,
parasomnia, and sleep-related movement disorderwere found the different processes from insomnia andcircadian rhythm disorders. We did not observe any
early warning signs or aggravating factors. Awareness ofmental and physical disorders due to drowsiness during
the daytime was recognized but because of minimum
knowledge about these sleep disorders, nobody perceived
any threat or necessity to seek treatment. Therefore, thefactors that triggered them to take action were: when theirfamily brought these factors under their notice, or at theirHealth Promot Perspect, 2021, Volume 11, Issue 1

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Toyoshima et al

workplace, they were recommended to go for a medical
examination, and found out, when they were exhibiting
physical symptoms or diseases such as obesity, diabetes,and depression. They responded that they did not knowwhom they should consult, did not feel the necessity
to undergo examination or treatment, interruption of
medical treatment, and they could not lose weight in caseof obesity.
Discussion
This study aimed to find out the process of developing
sleep disorders and identified underlying factors andits impact on work. We believe a holistic approachis necessary with respect to occupational nursing
perspective, paying attention to not merely on working
environment and sleep hygiene, but also, emphasis on
psychosocial factors to intervene. Nursing is a medical
profession, and it is important to strengthen the services
and inter-professional co-operation in healthcare. This
study revealed that Japanese cultural practices of longworking hours, drinking customs after the work, andburden of housework reduce the total sleep duration
which influenced to initiate the early warning signs of
sleep disorders. Sleep patterns differ among countries
influenced by sociodemographic and cultural status.23 In
our study, we found that sleep disorders were related tophysical, psychosocial, environmental, behavioral, andcombined factors. Similar findings were observed thatsleep disorders increased with medical and psychologicalcomorbidities.24 Another study documented that sleep
disturbance has a significant association with physical,
psychosocial, and environmental factors.25 This study also
described the types of features as participants’ personal,
family and working environment can influence to develop
sleep disorders.
Sleep has a vital role on various body systems including
brain functions. Our results indicated that occupational
health services, like sleep hygiene education or personalcounseling might be effective for improving the quality ofworkers’ sleep when they displayed some early warning
signs and aggravating factors. Many occupational factors
may interfere with sleep which may cause significantly
short and long-term effects on health and safety.26 In
Japan, occupational factors such as higher work demands,
longer working hours, shift work, etc. are individuallyassociated with sleep disturbance.27 Similarly, someother Asian countries such as South Korea documented
that violence, discrimination, work-life imbalance,
job dissatisfaction, high work demands and intensity,and job insecurity are the common responsible factors
for sleep disturbance.28 The current study identified
some responsible factors on how workers develop sleep
disorders like long working hours, caregiving practice,housework, nurturing baby, jet lag, social jet lag, somedisease conditions (i.e. itching, pain), family or personal
conflict and behavioral habits. Several studies found that
jet travel and night work resulted in a huge change at the92

Health Promot Perspect, 2021, Volume 11, Issue 1time for sleep and wake, a large phase shift, producing
circadian misalignment between sleep, work, meals andthe internal circadian rhythms.29,30 The high job demands
and overtime are important factors for long working
hours that have been associated with sleep disturbances.27
However, long working hours and sleep complaints might
be partially accounted for behavioral correlates like ahigher level of Internet addiction, alcohol consumption
and activities tended to have poorer sleep quality.31
The negative psychological and physiological impacts
of inadequate sleep also have been well-documented,
including emotional incidents,32 and increased risks ofparticipating in hazardous behaviors (e.g., tobacco and/or
alcohol consumption, driving while under the influenceof insufficient sleep).33 Based on the aforementioned
discussion, studies recommended developing a policy forscheduled naps and providing a quiet room for rest breaks
and naps can be a countermeasure to reduce fatigue,
which can provide benefits to the workers.34
In this study, we described categories of early warning
signs and aggravating factors and how workers develop
sleep disorders. Some aggravating factors such as
accumulation of fatigue, urgency, and feelings of guilt forbeing absent from work due to chronic diseases were related
to work-life balance. The most common aggravating factor
was fatigue for workers, especially those who were doinga shifting duty. Shifting duties of the workers reduced thequality and quantity of sleep that negatively interrupted
their quality of life and health including social activities.35
This study indicates psychological stress due to caregiving(taking care of ill family members) and housework without
surrounding supports can also cause fatigue. There are two
key contributors to develop fatigue, insufficient sleep anddisruptions in the normal sleep cycle cause to circadianmisalignment. Tanaka et al. reported that alterationsin the biological rhythm increased circadian biologicaldysfunctions, such as energy metabolism, autonomic
activity, endocrine, and neurocognitive dysfunctions.36
It is well documented that chronic illness such as
cardiovascular disease, diabetes, rheumatoid diseases,
and respiratory disorders are associated with reduced
health-related work performance and poor quality ofworking life after the disease onset.37,38 Similarly, lack ofquality sleep can negatively impact work performance,
attention to tasks, and decision-making factors that may
increase workload and work-related stress.39 In addition,
discrimination and prejudice at the workplace which havebeen associated with emotional stress disproportionallyaffect workers with chronic diseases.40 These results
suggest the need to promote proper working hours and theneed for workers to have time to refresh. These findings
also demonstrate the importance of a good balance
between the treatment of chronic diseases and working.
From the above discussion, it appears that individuals
would be benefited from those aggravating factors by amulti-disciplinary approach that helping the integration
process that encompasses the physical, emotional,

Toyoshima et alsocial, vocational, and existential work of chronic illness
adjustment. Moreover, rehabilitative programs, healthpromotion programs and more involvement from healthprofessionals, particularly nurses, have been advocatedas potentially important services for adults with chronic
illness to learn to optimize life.41 Based on the above
results, addressing the causes of early warning signs andaggravating factors, it may become possible to constructa program to prevent the onset of sleep disorders for
employees who suffer in the occupational health field. In
occupational health settings, workers with sleep-related
support do not always require diagnosis at a medical
institution. It is necessary that a worker who has difficultyin sleeping, regardless of the presence or absence of asleep disorder-related diagnosis, should be provided withoccupational support in order to prevent developing sleep
disorders.
Furthermore, we explained why participants were
unsuccessful with coping strategies before developing
sleep disorders. Some participants did their best given theirown situation and tried to improve their lives such as byadapting to a new job or family environment. It confirmedthat non-pharmacologic management such as sleep
hygiene education, counseling, and introducing social
resources in occupational health would be helpful as aneffective coping strategy against sleep disorders. The highly
stressed workers may be more prone to sleep disturbance,nightmares, daytime malfunction, and lack of rest due tosleep deprivation. In this regard, appropriate stress coping
strategies can improve sleep disorders even in the mosthighly stressed individuals.42 Effective coping styles thatinvolve actively engaging problems, positively interpreting
situations, and using humor lead to faster resolution ofdifficulties and help maintaining the psychological healthof an individual during times of stress, thereby allowing agreater sense of safety and security. Coping could be either
problem-focused (e.g., by employing problem solving andtime management strategies) or emotion-focused (e.g.,through mindfulness, relaxation, and obtaining emotional
support from colleagues or friends).43 So, the appropriate
strategy should be implemented to reduce work stress andsleeping disorders from four main coping strategies whichhave been discussed elsewhere.44
Our findings revealed that workers with sleep disorders
are likely to have a negative impact of low performance atwork or be absent from work. This is in line with a previous
study corroborating that sleep disorders are costly healthproblems and resulting in the high estimated costs tosociety of leaving the most prevalent sleep disorders
untreated that would be incurred by providing effective
management.45
The study has several limitations. The participants
were recruited through a snowball sampling method in
the community, so selection bias is a concern. The study
participants were also selected from a single city in Japan
which can restrict the generalizability of the study. During
the data collection, some participants were asked to tell

the previous history related to their sleep disorders, sorecall bias is another concern.
Implications for occupational health nursing practice
In Japan, there is a major change in the labor force due toincreasing aged population. As a consequence, Japanese
occupational health nurses adopted dramatically inrecent years to handle new and changing risks among
workers.46 Recently, companies adopted a good work-life
environment such as short working hours for childbearing
women and stop caregiving for all workers. However, still
there are many issues to pay attention as an occupational
health nurse.
The findings of this study can be used for a program
to manage sleeping disorder for workers. We havedeveloped an educational program and booklet andapplied it to company workers, in which we listed all
factors generated from this study and added assessment
tools and instructions on how to deal with those factors
specifically. We also described the process of sleep
disorders development. In the booklet, we brought
attention to the early warning signs before the onset. As
an occupational health nurse, not only providing sleep
hygiene information, we can pay more attention to these
individuals and environmental factors and can facilitate
in case management and collaborate with companies todeal with the work conditions. The educational programand materials we developed based on this study could be
widely implemented nationally and internationally forfurther evaluation by the occupational health nurses.
Conclusion
Among the study participants, nobody had the knowledge
about the category of sleep disorders. There are a certain
number of participants who had no understanding of their
sleep difficulties such as SAS and other sleep disorders.
They could not recognize, did not ask for supports, did not
follow coping strategies, and tried to deal with disorders
by themselves. Therefore, routine screening system toevaluate workers’ sleep condition by using standard tools/
questionnaires, counseling and treatment are essential. It isalso important to know the types of sleep disorders whichallow accurate diagnosis, improved communication with asleep specialist, and standardization of management plan
to improve the quality of life. This study suggests a holistic
approach involving both workers and occupational healthnurses for the prevention and control of sleep disorders.
Acknowledgements
The authors would like to thank all participants who shared theirexperiences and perceptions in this study.
Funding
This study is carried out with funding of the Grants-in-Aid
for Scientific Research Program (KAKENHI), Japan (No.
15H05078).
Health Promot Perspect, 2021, Volume 11, Issue 1

93Toyoshima et alCompeting interests
The author(s) declared no potential conflicts of interest withrespect to the research, authorship, and/or publication of thisarticle.
Ethical approval
The study protocol and procedures were approved by the ethics
committee of Hiroshima University, Japan (E-80). Written
informed consent was obtained individually from all theparticipants.
Authors’ contributions
AT and MM were responsible for the conception and designof the study. AT involved in data collection. AT, MM, HY, and
KK worked on data analysis and interpretation. AT, EH and
YJ drafted the original manuscript. MM, HY, MMR and KK
critically revised and finalized the manuscript. All authors readand approved the final manuscript.
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Appendix 1. Standards for Reporting Qualitative Research (SRQR)
O’Brien B.C., Harris, I.B., Beckman, T.J., Reed, D.A., & Cook, D.A. (2014). Standards for reporting qualitative research: a synthesis of recommendations.
Academic Medicine, 89(9), 1245-1251.
No. Topic

Item

Title and abstract☑S1 Title →Title page

Concise description of the nature and topic of the study identifying the study as qualitative or
indicating the approach (e.g., ethnography, grounded theory) or data collection methods (e.g.,interview, focus group) is recommended→We used a qualitative study and described in the title.

☑S2 Abstract→P1 & 2

Summary of key elements of the study using the abstract format of the intended publication; typically
includes objective, methods, results, and conclusions

Introduction☑S3 Problem formulation →P3 & 4☑S4 Purpose or research question→P4

Description and significance of the problem/phenomenon studied; review of relevant theory andempirical work; problem statement
Purpose of the study and specific objectives or questions

Methods☑S5 Qualitative approach and research

Qualitative approach (e.g., ethnography, grounded theory, case study, phenomenology, narrative
research) and guiding theory if appropriate; identifying the research paradigm (e.g., positivist,
constructivist/interpretivist) is also recommended☑S6 Researcher characteristics and reflexivity

Researchers’ characteristics that may influence the research, including personal attributes,
qualifications/experience, relationship with participants, assumptions, or presuppositions; potential
or actual interaction between researchers’ characteristics and the research questions, approach,methods, results, or transferability

paradigm→P4→P5☑S7 Context →P4 & 5

Setting/site and salient contextual factors; rationalea☑S8 Sampling strategy →P5☑S9 Ethical issues pertaining to human subjects

How and why research participants, documents, or events were selected; criteria for deciding when
no further sampling was necessary (e.g., sampling saturation); rationalea☑S10 Data collection methods →P5 & 6

Types of data collected; details of data collection procedures including (as appropriate) start andstop dates of data collection and analysis, iterative process, triangulation of sources/methods, andmodification of procedures in response to evolving study findings; rationalea→P22☑S11 Data collection instruments andDocumentation of approval by an appropriate ethics review board and participant consent, or
explanation for lack thereof; other confidentiality and data security issues

technologies →P5 & 6

Description of instruments (e.g., interview guides, questionnaires) and devices (e.g., audio recorders)
used for data collection; if/how the instrument(s) changed over the course of the study☑S12 Units of study →P5-7

Number and relevant characteristics of participants, documents, or events included in the study;level of participation (could be reported in results)☑S13 Data processing →P6 & 7

Methods for processing data prior to and during analysis, including transcription, data entry,
data management and security, verification of data integrity, data coding, and anonymization/
deidentification of excerpts☑S14 Data analysis →P7

Process by which inferences, themes, etc., were identified and developed, including researchers
involved in data analysis; usually references a specific paradigm or approach; rationalea☑S15 Techniques to enhance trustworthiness →P8

Techniques to enhance trustworthiness and credibility of data analysis (e.g., member checking, audit
trail, triangulation); rationalea

Results/Findings☑S16 Synthesis and interpretation →P8-14

Main findings (e.g., interpretations, inferences, and themes); might include development of a theory
or model, or integration with prior research or theory☑S17 Links to empirical data →Table 1

Evidence (e.g., quotes, field notes, text excerpts, photographs) to substantiate analytic findings

Discussion☑S18 Integration with prior work, implications,transferability, and contribution(s) to the field→P14-21☑S19 Limitations →P20

Short summary of main findings; explanation of how findings and conclusions connect to, support,
elaborate on, or challenge conclusions of earlier scholarship; discussion of scope of application/
generalizability; identification of unique contribution(s) to scholarship in a discipline or field
Trustworthiness and limitations of findings

Other☑S20 Conflicts of interest →P22
☑S21 Funding →title page P22

Potential sources of influence or perceived influence on study conduct and conclusions; how thesewere managed
Sources of funding and other support; role of funders in data collection, interpretation, and reporting

The rationale should briefly discuss the justification for choosing that theory, approach, method, or technique rather than other options available, theassumptions and limitations implicit in those choices, and how those choices influence study conclusions and transferability. As appropriate, the rationale forseveral items might be discussed together.
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