Masaya Takahashi

National Institute of Occupational Safety and Health JAPAN

Objectives: The prevalence of work-related low back pain (LBP) is high among care workers and can negatively affect quality of work life (QWL). To improve workplace satisfaction, this study aimed to identify factors influencing QWL among seniors' care workers with severe LBP. Methods: A questionnaire survey including items on demographics, quali...

Objectives: This study examines the mediating and moderating effects of psychological detachment (PD) based on the stressor-detachment model long term. Methods: Two waves of web-based surveys, 28 months apart, yielded 3,556 responses from Japanese workers. Comparisons between models that included mediating and moderating effects of PD, and rever...

職業性のばく露による労働者の負担を減らすためには，ばく露の時間的な側面を考慮した検討が必要である．そこで本研究では，職場における様々な出来事の特に年単位の長期的なばく露に着目し，高ストレスとの関連を検証した．職場における出来事については，精神障害の労災認定基準にある 36 の具体的出来事を対象とした．労働者を対象に WEB 追跡調査を行った．参加者は個人属性に加え，職場での各出来事の過去 1 年の経験と職業性ストレス簡易調査票に回答した．2016 年 11 月と 2019 年 2 月に調査を行い，11 ,729 名の初回調査参加者から 3 ,556 名が追跡できた．初回調査で高ストレス判定だった者を除き，3 ,071 名を解析対象とした．高ストレス判定を従属変数，出来事の経験回答パターン（経...

Background Although various work-related adverse events affect workers’ mental health, the association between long working hours and mental disorders remains unclear. We investigated the characteristics of overtime work and work-related adverse events among all cases of compensated work-related suicide in Japan to empirically reveal the context of...

Purpose We aimed to examine the prospective associations of monthly working hours measured in a month, the 6-month averaged hours, and the frequency of long working hours (≥ 205 h/month) during the past 6 months with health indicators. Methods This study included 6,806 Japanese company workers (response rate = 86.6%). Data on the workers’ monthly...

Objectives: This study examined the characteristics of occupational mental disorders among those involved in the transport and postal activities in the trucking industry. Method: We examined 237 out of 3517 cases of occupational mental disorders, compensated between the fiscal years 2010 and 2017. An assessment was made for sex, "life-or-death"...

Objective A sufficient duration of time off after work is necessary to ensure workers’ health. Better quality of off-job time can also facilitate recovery from fatigue, but its quantitative influence is largely unknown. We aimed to examine how off-job time quality (as measured by the frequency of emailing after work), and off-job duration is associ...

Using a patient lift to assist in transfer can alleviate physical burden and reduce the risk of lower back disorders. However, it requires more time than applying manual transfer techniques, often resulting in caregivers opting out of its use. This study used two experiments to examine the lifting and lowering velocities experienced by caregivers a...

How work burden affects physical and mental health has already been studied extensively; however, many issues have remained unexamined. In 2017, we commenced a prospective cohort study of workers at companies in Japan, with a follow-up period of 5–10 years, in order to investigate the current situation of overwork-related health outcomes. From 2017...

Objective: The shortage of caregivers in care facilities has become a problem in Japan. Building a comfortable workplace and improving the quality of working life (QWL) of caregivers are essential. However, the factors of QWL that should be prioritized remain unclear. The purpose of this study was to identify the major factors currently affecting...

The daily rest period (DRP) is the daily inter-work interval and can include a sleep opportunity, leisure time, and other non-work time. A longer DRP may allow workers to increase time in bed (TIB) and adjust sleep timing, and that may reduce sleep problems such as short sleep duration, sleep debt, social jetlag, and poor sleep quality. The present...

Purpose We aimed to cross-sectionally investigate how work and sleep conditions could be associated with excessive fatigue symptoms as an early sign of Karoshi (overwork-related cerebrovascular and cardiovascular diseases; CCVDs). Methods We distributed a questionnaire regarding work, sleep, and excessive fatigue symptoms to 5410 truck drivers, as...

Long working hours are considered to be associated with increases in cerebrovascular and cardiovascular diseases such as stroke and coronary heart disease, and are also important factors for karoshi. To maintain the health of workers and reduce karoshi, it is necessary to clarify the cardiovascular burden caused by long working hours. In recent yea...

A no-lift policy, which states that care recipients should not be lifted using human power but rather using care equipment, has been spreading since about 2014 in Japan. The purpose of this study is to examine whether severe low-back pain (LBP) risk factors changed between 2014 and 2018. Questionnaires for administrators and caregivers were distrib...

The aim of the study was to examine the relationship between sleep problems and objective driving behaviors of short-haul commercial truck drivers in Japan. One hundred and ten male short-haul commercial truck drivers’ sleep duration, sleep quality (Pittsburgh Sleep Quality Index), and frequency of sleepiness at the wheel were measured by survey in...

Objectives: The number of part-time staff is increasing every year, and they are becoming very essential in completing the workforce. Healthcare and assurance for part-timers will be an important issue in the future. The purpose of our study was to collect recent data and examine the status of health management for part-time employees in workplace...

This study aimed to examine the actual situation and background factors associated with overwork-related disorders, such as cerebrovascular/cardiovascular disease (CCVD) and mental disorders, among teachers/workers in education/school services. Eighty-two eligible cases involving compensation for CCVD and mental disorders of the teachers/workers in...

While a number of work-related events have been proposed as risk factors for depression, a majority of studies have focused only on a few events in a single study. Therefore, we conducted a web-based longitudinal study to comprehensively investigate the impact of various work-related events on depressive symptoms. Ten thousand Japanese workers repr...

PurposeStep test protocols are typically based on the heart rate (HR) measured either during exercise or during recovery. This study developed a new step test protocol to estimate maximal oxygen consumption (\(\dot{\text{{V}}}{{\text{O}}}_{\text{2max}}\)) based on HRs measured during and after exercise, assessed the criterion validity of the model,...

Table 3 of the above paper appeared incorrectly in print. Percentage figures on the table were inadvertently listed as negative values. These errors were corrected in online versions of this paper, as shown below.

This study examines how working parents’ work attitudes (i.e., workaholism and work engagement) are associated with their child’s psychological well-being. Based on the Spillover-Crossover model (SCM), we hypothesize that (a) work-to-family spillover (i.e., work-to-family conflict and facilitation) and (b) employee happiness will sequentially media...

Objectives We examined the association of workplace social capital (WSC), including structural and cognitive dimensions, with refraining from seeking medical care (RSMC) among Japanese employees. Design One-year prospective cohort study. Setting and participants We surveyed 8770 employees (6881 men and 1889 women) aged 18–70 years from 12 firms i...

Objectives The association between near-misses/minor injuries and moderate/severe injuries has yet to be investigated longitudinally. This study aimed to examine the longitudinal association between near-misses/minor injuries and moderate/severe injuries by the presence/absence of depressive symptoms using 1-year follow-up data obtained from a nati...

The relationship between overwork and health-related issues among systems engineers (SEs) and programmers (PGs) has been recently gaining attention, as the working environment continues to change rapidly due to the information technology revolution. This study elucidated the actual conditions and characteristics of SEs and PGs who were approved for...

This study aimed to examine the status of depression symptoms and occupational stress factors that triggered these symptoms among workers in medical and welfare industries. Web-based surveys were conducted in 2016 and 2019 among research company survey respondents regarding their work, life and health. This study extracted data for medical services...

Objectives: The work interval duration between the end of one workday and the start of the following workday is referred to as the daily rest period (DRP). The present study examined whether DRP – a proxy for sleep opportunity between work shifts – is associated with indicators of sleep debt and social jetlag among daytime workers. Methods: We used...

Background: Sedentary behavior (SB) and cardiorespiratory fitness (CRF) are important issues in occupational health. Developing a questionnaire to concurrently assess workers' SB and CRF could fundamentally improve epidemiological research. The Worker's Living Activity-time Questionnaire (WLAQ) was developed previously to assess workers' sitting t...

Objectives: Karoshi problems (overwork-related deaths and disorders caused by cerebrovascular and cardiovascular diseases) still occur in Japan. Truck drivers, who are in one of the riskiest occupations, are reported to show an increased prevalence of hypertension, obesity, hyperlipidemia, and diabetes, which are characteristic of Karoshi. Their h...

This cross-sectional study aimed to explore work and rest conditions associated with overfatigue in truck drivers. A total of 1,911 male truck drivers participated in a questionnaire survey regarding their employment conditions, work habits, rest habits, sleep habits, health status, and subjective fatigue. Compared to local drivers who worked durin...

This study examined the association between occupational sedentary behavior (SB) and health-related parameters.We assessed 119 Japanese workers (age: 44.6±7.7 years) using by the Worker’s Living Activity-time Questionnaire(WLAQ) to determine occupational sitting time. Cardiorespiratory fitness (VO2max), blood values by health checkup within 1-year,...

We investigated the association between the period of exposure and changes in urinary excretion of chromium and nickel among rotating shift workers in a stainless-steel plant. The study participants were composed of two groups: the workers who were occupationally exposed to metals (“exposed group”) and those who were not occupationally exposed to m...

Objectives This study aimed to clarify haemodynamic responses of different age groups to simulated long working hours. Methods Men of three age groups participated in this study (16 in their 30s (mean 33.9±2.7 years old), 15 in their 40s (45.5±2.9) and 16 in their 50s (54.1±2.7)). All participants conducted 12 45-min personal computer-based tasks...

Long working hours and a lack of sleep have been suggested to negatively affect the safety of workers. Here, we examined the association between long working hours/sleep-related problems and near-misses/injuries in industrial settings using a nationally representative sample of workers in Japan. Based on the composition ratio of workers by industry...

Objectives The incidence of occupational low back pain (LBP) is high among caregivers. The use of care equipment and training about care methods could prevent LBP among caregivers. However, in care facilities in Japan, these measures are not adequately employed. Moreover, the care facilities have faced issues regarding poor staffing in recent years...

The majority of patients with non-specific low back pain (LBP) suffer from chronic pain. Psychosocial factors play an important role in the chronicity of LBP. To explore the risk factors for chronic disabling LBP in detail, we assessed its various risk factors in Japanese workers, using data from the Cultural and Psychosocial Influences on Disabili...

This study aimed to examine hemodynamic responses and the necessity of breaks under long working hours. Thirty-eight healthy males conducted PC-based work from 9:10 to 22:00. Nine 10-minute short breaks and two long breaks (a 1-hour break and a 50-minute break) were provided, and hemodynamic responses were measured regularly during this period. The...

Background: The European Union's Working Time Directive stipulates recovery periods as "Eleven consecutive hour daily rest periods (DRPs) between working days." In Japan, adopting this regulation has been discussed. Objective: To examine the association between weekday DRPs and recovery from fatigue by conducting a one-month observational study usi...

Objectives The present study examined hemodynamic responses of normotensive and untreated hypertensive participants under simulated long working hours (LWH) - 13 hours - in an experimental laboratory study. Methods Thirty-five men participated in this study. Twenty-two of these participants were categorized into the normotensive group (systolic blo...

Many care workers at elderly care facilities in Japan suffer occupational low back pain (LBP) despite the utilization of welfare equipment. When introducing welfare equipment such as hoists and sliding boards, education on appropriate care methods using welfare equipment is usually conducted, but the effect of education diminishes with time. This i...

Introduction Quality of Sleep has been linked to poor health. While work-family spillover is associated with health problems and impaired work performance of workers, previous findings were inconsistent on, the association between work-family spillover and sleep quality. No study was conducted in non-western countries. The objective of this study w...

Introduction Quality of Sleep has been linked to poor health. While work-family spillover is associated with health problems and impaired work performance of workers, previous findings were inconsistent on, the association between work-family spillover and sleep quality. No study was conducted in non-western countries. The objective of this study w...

This session aims to discuss about off-job experiences, health, and well-being by focusing on daily rest periods and leisure crafting Dr. Masaya Takahashi¹, Dr. Jessica de Bloom², Dr. Sara Arphorn³ ¹National Institute of Occupational Safety and Health, Kawasaki, Japan ²University of Tampere, Tampere, Finland ³Mahidol University, Bangkok, Thailand

This study examined the association between health-related risks and sitting time in three different domains covering a worker’s typical life. We investigated the beneficial effect of replacing sitting time with standing/walking time in the workplace using the isotemporal substitution model (ISM). The survey was administered through the Internet. W...

Objective: This study aimed to clarify whether work-related adverse events in cases involving compensation for mental disorders and suicide differ by sex and industry using a database containing all relevant cases reported from 2010 to 2014 in Japan. Methods: A total of 1,362 eligible cases involving compensation for mental disorders (422 female...

Objectives: This study aimed to describe the sleep quantity, sleep quality, and daily rest periods (DRPs) of Japanese permanent daytime workers. Methods: Information about the usual DRP, sleep quantity, and sleep quality (Japanese version of the Pittsburgh Sleep Quality Index: PSQI-J) of 3867 permanent daytime workers in Japan was gathered throu...

The present study examined the influences of long working hours on hemodynamic responses in order to provide evidence for examining precautions against Karoshi, which was defined as death from overwork. Thirty-nine healthy male participants conducted 12 hours of PC-based mental work in a laboratory. Hemodynamic responses were measured regularly fro...

Objective: We aimed to examine the effects of the daily rest period (DRP) on resting blood pressure (BP) and fatigue and determine the optimal DRP for daytime workers. Methods: Fifty-four daytime employees participated in a 1-month observational study. BP was measured thrice at the workplace. Employees underwent a pre- and post-survey to determi...

Background This study examined the prospective association of workplace social capital (WSC) with major depressive episode (MDE) among Japanese employees. Methods A 3-year prospective cohort study was conducted among 1058 employees from a private think-tank company who participated in a baseline survey; after excluding those with MDE in the past 1...

[This corrects the article DOI: 10.1371/journal.pone.0148157.].

This study explored the effect of workplace psychosocial factors (job demand, job control, and workplace social support) on dual-earner couples in Japan having additional children, using a prospective study design. We conducted a 2-year prospective cohort study with 103 dual-earner couples with preschool children in Japan, as part of the Tokyo Work...

Objectives: This observational study aimed to determine how 1-year changes in work time control (WTC) have an impact upon objectively measured fatigue and sleep among employees. Methods: Thirty-nine employees were divided into two groups according to whether or not their WTC increased from baseline to 1 year later. Psychomotor vigilance task (PV...

Objective: The purpose of this study was to clarify the causes of low back pain among workers in care facilities for the elderly after the introduction of welfare equipment. Methods: We conducted anonymous questionnaire surveys among administrators and care workers in eight elderly care facilities. The questionnaires were designed to investigate...

The purpose of the study was to investigate the association between parental workaholism and child body mass index (BMI) among Japanese dual-income families. In 2011, 379 dual-income families from urban Tokyo with children aged 0–5 years were recruited for a baseline survey, and 160 (42.2%) were followed up in 2012. Demographics, workaholism, work...

Objective: This study investigated work engagement as a baseline predictor of onset of major depressive episode (MDE). Methods: The study used a prospective cohort design, conforming to the STROBE checklist. Participants were recruited from the employee population of a private think tank company (N = 4,270), and 1,058 (24.8%) of them completed a...

STROBE checklist of information to include when reporting a cohort studies. (DOC)

Katakori is a Japanese word, and there is no clear English translation. Katakori consists of two terms, Kata means neck and shoulder, kori means stiffness. Consequently, Katakori is defined as neck and shoulder discomfort or dull pain. Katakori is a major somatic complaint and has a large impact on workers. To examine the association between onset...

This study examined whether a higher level of psychological detachment during non-work time is associated with better employee mental health (Hypothesis 1), and examined whether psychological detachment has a curvilinear relation (inverted U-shaped pattern) with work engagement (Hypothesis 2). A large cross-sectional Internet survey was conducted a...

Objective: The aim of the present study is to demonstrate the distinctiveness of work engagement and workaholism by examining their relationships with sleep quality and job performance. Method: A total of 447 nurses from 3 hospitals in Japan were surveyed using a self-administrated questionnaire including Utrecht Work Engagement Scale (UWES), th...

We investigated how night shift duration and sleep problems were jointly associated with disabling low back pain (LBP) among workers in different occupations. An online-survey was conducted regarding work schedules, disabling LBP, sleep problems, and other relevant factors in 5,008 workers who were randomly selected from a market research panel. Mu...

Absence due to mental disease in the workplace has become a global public health problem. We aimed to evaluate the influence of presenteeism on depression and absence due to mental disease. A prospective study of 1831 Japanese employees from all areas of Japan was conducted. Presenteeism and depression were measured by the validated Japanese versio...

Objectives Sickness absence due to mental disease in the workplace has become a global public health problem. Previous studies report that sickness presenteeism is associated with sickness absence. We aimed to determine optimal cutoff scores for presenteeism in the screening of the future absences due to mental disease. Methods A prospective study...

Brain-derived neurotrophic factor (BDNF) is involved in the survival, development, and synaptic plasticity of neurons. BDNF is believed to be associated with the pathophysiology of psychiatric disorders. Several studies have suggested the relevance of DNA methylation in its promoter region with depression. Here, we report different methylation stat...

Shift work poses a significant threat to multiple aspects of working life. The present review addresses the health, safety/performance, and psychosocial issues associated with shift work. Recent studies have revealed that health disorders due to working in shifts are closely related to dysfunction of sleep and the circadian timing system. Safety an...

Occupational conditions, together with socioeconomic status, may modulate sleep. This study examined the association of occupational conditions and socioeconomic status with actigraphic measures of sleep in workers. Fifty-five employees (40 ± 12 years) wore a wrist actigraph during sleep for seven consecutive nights. Sleep variables addressed inclu...

Recent epidemiological research in Europe has reported that two groups of job demands, i.e., challenges and hindrances, are differently associated with work engagement. The purpose of the present study was to replicate the cross-sectional association of workload and time pressure (as a challenge) and role ambiguity (as a hindrance) with work engage...

Despite known beneficial effects of social support on cardiovascular health, the pathway through which sources of support (supervisor, coworkers, family/friends) influence inflammatory markers is not completely understood. We investigated the independent and moderating associations between social support and inflammatory markers. A total of 137 mal...