Journal of Occupational Health
Online ISSN : 1348-9585
Print ISSN : 1341-9145
ISSN-L : 1341-9145
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Review Articles
  • Frederieke G. Schaafsma, Gerben Hulsegge, Merel A. Jong, Joyce Overvli ...
    Type: REVIEW ARTICLE
    2021 Volume 63 Issue 1 e12189
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: Workplace-based selective prevention of mental health problems currently relies on subjective evaluation of stress complaints. Hair cortisol captures chronic stress responses and could be a promising biomarker for the early identification of mental health problems. The objective was to provide an overview of the state-of-the-art knowledge on the practical value of hair cortisol in the occupational setting.

    Methods: We performed a scoping review of cross-sectional and longitudinal studies in PubMed, Embase, and PsycINFO up to November 2019 assessing the relations of hair cortisol with work-related stressors, perceived stress, and mental health outcomes in healthy workers.

    Results: We found five longitudinal studies, of which two observed an increase in work-related stressors to be associated with higher hair cortisol, one found a relation with lower hair cortisol and one did not find a relationship. Findings of cross-sectional studies were also mixed. The one available longitudinal study regarding mental health showed that hair cortisol was not related to depressive symptoms.

    Conclusions: Hair cortisol measurement within occupational health research is still in its early stage and more longitudinal studies are urgently needed to clarify its relationship with work-related stressors and perceived stress before hair cortisol can be used to identify workers at risk for mental health problems.

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Brief Reports
  • Kate Hayman, Jesse McLaren, Dezi Ahuja, Carolina Jimenez Vanegas, Hasa ...
    Type: BRIEF REPORT
    2021 Volume 63 Issue 1 e12195
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Introduction: Emergency physicians frequently provide care for patients who are experiencing viral illnesses and may be asked to provide verification of the patient's illness (a sick note) for time missed from work. Exclusion from work can be a powerful public health measure during epidemics; both legislation and physician advice contribute to patients’ decisions to recover at home.

    Methods: We surveyed Canadian Association of Emergency Physicians members to determine what impacts sick notes have on patients and the system, the duration of time off work that physicians recommend, and what training and policies are in place to help providers. Descriptive statistics from the survey are reported.

    Results: A total of 182 of 1524 physicians responded to the survey; 51.1% practice in Ontario. 76.4% of physicians write at least one sick note per day, with 4.2% writing 5 or more sick notes per day. Thirteen percentage of physicians charge for a sick note (mean cost $22.50). Patients advised to stay home for a median of 4 days with influenza and 2 days with gastroenteritis and upper respiratory tract infections. 82.8% of physicians believe that most of the time, patients can determine when to return to work. Advice varied widely between respondents. 61% of respondents were unfamiliar with sick leave legislation in their province and only 2% had received formal training about illness verification.

    Conclusions: Providing sick notes is a common practice of Canadian Emergency Physicians; return-to-work guidance is variable. Improved physician education about public health recommendations and provincial legislation may strengthen physician advice to patients.

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Original Articles
  • Meng-Ting Tsou, Tsung-Ping Pai, Te-Ming Chiang, Wei-Hsin Huang, Hsiu-M ...
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12188
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: The cross-sectional study aimed to analyze the association between burnout, work-related factors, and metabolic syndrome (Mets) in nurses from several departments of a tertiary hospital in Taiwan. Exploring biomarkers could provide for prevention.

    Methods: Demographic data were obtained through a written questionnaire and include the following information: gender, age, education level, psychosocial and work situations, such as departments, working hours, work shift, depression, and sleep time. Burnout was evaluated according to the Chinese Burnout inventory, Mets was evaluated according to the criteria of the National Cholesterol Education Program of Taiwan-Treatment Panel for Adults III (NCEP-ATP III).

    Results: A total of 1758 nurses participated with a median age of 35.2 years. The prevalence of burnout and Mets was 6.4% and 13.84%, respectively. The results showed that burnout induced higher risk of Mets, odds ratio (OR) 1.70 (95% confidence interval, 1.04-3.05). Other factors, such as out-patient nurses, seniority (4-10 and >10 years), working hours (51-59 h/wk), nigh shift, Brief Symptom Rating Scale-5 (score 10-14 and ≧15), poor self-rated health status, and inadequate sleep time, led to higher risk of Mets. Biomarkers research showed that Glycated hemoglobin (Hba1c) was significantly associated with burnout nurses (OR = 24.72, P < .001), but thyroid-stimulating hormone and free thyroxin were not.

    Conclusions: Results suggested positive associations between burnout and Mets in nurses. For nurses with higher seniority, long hours of work, night shifts, poor physical and mental conditions, and poor lifestyle habits in different departments, strategies are needed to prevent burnout and Mets.

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  • Yuko Kachi, Takeo Fujiwara, Hisashi Eguchi, Akiomi Inoue, Sachiko Baba ...
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12196
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: Maternity harassment, known in English as pregnancy discrimination, remains prevalent in developed countries. However, research examining the mental health effects of maternity harassment is lacking. We aimed to examine the association between maternity harassment and depression during pregnancy in Japan.

    Methods: A cross-sectional Internet survey was conducted on 359 pregnant employees (including women who were working at the time their pregnancy was confirmed) from May 22 to May 31, 2020, during which time a COVID-19 state of emergency was declared. Maternity harassment was defined as being subjected to any of the 16 adverse treatments prohibited by national guidelines. Depression was defined as a score of ≥9 on the Edinburgh Postnatal Depression Scale (Japanese version). Logistic regression analysis was performed.

    Results: Overall, 24.8% of the pregnant employees had experienced maternity harassment by supervisors and/or colleagues. After adjusting for demographics, pregnancy status, work status, and fear of COVID-19, pregnant employees who experienced maternity harassment were more likely to have depression than those who did not (odds ratio 2.48, 95% confidential interval 1.34-4.60). This association was not influenced by whether they were teleworking or not as a COVID-19 measure.

    Conclusions: One quarter of pregnant employees experienced maternity harassment and had a higher prevalence of depression than those who did not. Being physically away from the office through teleworking may not reduce the effect of maternal harassment on depression. To protect the mental health and employment of pregnant women, employers should comply with the laws and take measures to prevent maternity harassment.

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Field Studies
  • Tomohisa Nagata, Daisuke Ito, Masako Nagata, Ayumi Fujimoto, Ryotaro I ...
    Type: FIELD STUDY
    2021 Volume 63 Issue 1 e12198
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: The health effects of telework, which was introduced extensively in the immediate context of the COVID-19 pandemic crisis in Japan, on teleworkers, their families, and non-teleworkers, are unknown. Accordingly, we developed a rapid health impact assessment (HIA) to evaluate positive and negative health effects of telework on these groups and recommended easily implementable countermeasures.

    Methods: Immediately after an emergency was declared in Japan, we implemented a rapid, five-step HIA. We screened and categorized health effects of telework for the three above-mentioned groups, extracting their content, directionality, and likelihood. Following a scoping exercise to determine the HIA’s overall implementation, five experienced occupational health physicians appraised and prioritized the screened items and added new items. We outlined specific countermeasures and disseminated the results on our website. A short-term evaluation was conducted by three external occupational health physicians and three nurses.

    Results: Following screening and appraisal, 59, 29, and 27 items were listed for teleworkers, non-teleworkers, and family members of teleworkers, respectively, covering work, lifestyle, disease and medical care, and home and community. Targeted countermeasures focused on the work environment, business management, communications, and lifestyles for teleworkers; safety and medical guidelines, work prioritization, and regular communication for non-teleworkers; and shared responsibilities within families and communication outside families for family members of teleworkers.

    Conclusion: The HIA’s validity and the countermeasures’ practical applicability were confirmed by the external evaluators. They can be easily applied and adapted across diverse industries to mitigate the wider negative effects of telework and enhance its positive effects.

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Case Studies
  • Naomichi Tani, Fumiko Ichikawa, Risa Mitani, Junichi Akatsu, Susumu Od ...
    Type: CASE STUDY
    2021 Volume 63 Issue 1 e12201
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Background: A 45-year-old Japanese male pharmacist developed a stroke in December 2018; hence, he had left-sided hemiplegia due to the after-effects of cerebral stroke. This paper reports the return-to-work (RTW) and after RTW support for poststroke patients from a combined ergonomic and rehabilitation perspective.

    Methods: From April 2019 to July 2020, we visited hospitals and workplaces multiple times, making various preparations for workplace accommodation and exchanging information as follows: allowing staggered working hours; securing the flow routes in the back room; equipping a cane holder on his working desk; and adjusting the position of the work tablet. In August 2020, after RTW, we conducted a brief evaluation of residual motor function and an on-site task analysis, and we subsequently made a support tool.

    Results: In July 2020, his RTW was eventually realized. Moreover, as a result of introducing the tailor-made support tool, the duration of certain tasks that he had been claiming to be difficult was reduced when compared to that before support-tool use, and the average task duration before and after support-tool use was 32.8 s and 10 s, respectively (reduced by approximately 69.5%).

    Conclusion: To augment our efforts, hospital staff, support staff in his workplace, and his employer collaborated to make various workplace accommodations for the smooth realization of RTW before and after RTW. In the present case, the ergonomic and rehabilitation approach after RTW might have contributed to ease of task, work efficiency, and the potential for future job retention.

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Original Articles
  • Tomoaki Matsuo, Rina So
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12187
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: This survey aims to investigate consciousness regarding habitual exercise among workers in urban areas and to analyze the associations of workers’ socioeconomic status with their habitual exercise and cardiorespiratory fitness (CRF).

    Methods: Ten thousand participants, who worked in the Tokyo area of Japan, were recruited for the questionnaire-based survey. The questionnaire elicited participant's characteristics, socioeconomic status (eg, employment status and annual income), habitual exercise status, and consciousness regarding exercising. After the data-cleaning procedure, 9406 participants were selected for analyses. CRF was estimated by a validated equation model.

    Results: Some (32.9%) participants had an exercise habit, and 93% recognized that exercise is good for health. Of the nonexercise habit group (n = 6308), 73% wanted to develop an exercise habit, and “spare time (40%)” and “financial capability (16%)” were the two most necessary conditions for habituating exercise. As socioeconomic statuses increased, the odds ratios (ORs) for engaging in habitual exercise increased among full-time (1.22) versus part-time (reference) employees and those having high (1.76) versus low (reference) incomes, whereas the ORs for low CRF risk decreased among full-time (0.78) versus part-time (reference) employees and those having high (0.53) versus low (reference) incomes.

    Conclusions: Although most workers recognized the benefits of exercise, many were unable to develop exercise habits and believed that they could develop exercise habits if they had the time and financial capabilities. The survey suggests that workers with a higher socioeconomic status more likely to obtain favorable physical fitness, indicating a health disparity among workers in urban areas.

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Review Articles
  • Stefania Curti, Stefano Mattioli, Roberta Bonfiglioli, Andrea Farioli, ...
    Type: REVIEW ARTICLE
    2021 Volume 63 Issue 1 e12186
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: To evaluate the evidence of an association between occupational and non-occupational exposure to biomechanical risk factors and lateral elbow tendinopathy, medial elbow tendinopathy, and olecranon bursitis.

    Methods: We carried out a systematic review of the literature. We searched MEDLINE (up to November 2019) and checked the reference lists of relevant articles/reviews. We aimed to include studies where (a) the diagnosis was based on physical examination (symptoms plus clinical signs) and imaging data (if any); and (b) the exposure was evaluated with video analysis and/or direct measurements. A quality assessment of the included studies was performed along with an evaluation of the level of evidence of a causal relationship.

    Results: We included four studies in the qualitative synthesis: two prospective cohorts and two cross-sectional studies. All the included studies investigated “lateral/medial epicondylitis”, albeit the diagnosis was not supported by imaging techniques.

    Two cohort studies suggested that a combination of biomechanical risk factors for wrist/forearm is associated with increased risk of “lateral epicondylitis”. This association was not observed in the two included cross-sectional studies. The cohort studies suggested that a Strain Index score higher than 5 or 6.1 could double the risk of “lateral epicondylitis”. No association with increased risk of “medial epicondylitis” was observed.

    Conclusions: There is limited evidence of a causal relationship between occupational exposure to biomechanical risk factors and lateral elbow tendinopathy. For medial elbow tendinopathy, the evidence is insufficient to support this causal relationship. No studies on olecranon bursitis and biomechanical overload were identified.

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Original Articles
  • Kiyomasa Nakatsuka, Yamato Tsuboi, Maho Okumura, Shunsuke Murata, Tsun ...
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12194
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: Our study aimed to investigate the association between comprehensive workstations and neck and upper-limb pain (NUP) among office workers.

    Methods: This cross-sectional study included 307 office workers (median age, 39 years; 88% men). Workstations (presence of armrest, armrest position, number of monitors used, mouse position, mouse usage, keyboard usage, and keyboard position) were investigated in terms of 17 items and judged as “adequate” or “inadequate.” NUP was assessed using a numerical rating scale. NUP locations included the neck, shoulder, elbow, and wrist. In the statistical analysis, outcome variables were the presence of pain in each part, while explanatory variables were the number of inadequate workstations. Logistic regression analyses were conducted with adjustment for age, gender, working duration, and exercise habit.

    Results: The prevalence of neck pain was 47% (n = 143), shoulder pain was 50% (n = 153), elbow pain was 7.2% (n = 22), and wrist pain was 13% (n = 40). In the adjusted model, the number of inadequate workstations had significant positive associations with elbow pain (odds ratio [OR], 1.39; 95% confidence interval [CI], 1.06.1.81) and wrist pain (OR, 1.80; 95% CI, 1.17.2.26). However, the number of inadequate workstations was not significantly associated with neck pain or shoulder pain.

    Conclusions: Workstation-related factors (presence of armrest, armrest position, mouse usage, and keyboard usage) were significantly associated with elbow and wrist pain. Our findings suggest that workstations can contribute to elbow and wrist pain in office workers.

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  • Akira Ono, Hyogo Horiguchi
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12202
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: The present study investigated the quantitative relationship between blood lead (Pb-B) and urinary δ⁻aminolevulinic acid (ALA-U) in lead workers, and examined the Pb-B level that induces increases in ALA-U and the corresponding ALA-U.

    Methods: We collected 10 562 data sets on Pb-B, ALA-U, age, and smoking habits from 808 workers (771 males and 37 females) who underwent multiple lead poisoning medical examinations at a lead-acid battery and lead smelting plant in Japan between 1995 and 2018. Females were excluded, and data collected in 169 subjects prior to engaging in lead work were used as the control. Pb-B and ALA-U levels were measured by graphite furnace atomic absorption spectrophotometry and high-performance liquid chromatography respectively.

    Results: A significant dose-response relationship was observed between Pb-B and ALA-U based on Pb-B-classified observations of increases in ALA-U values and the prevalence of over-reference ALA-U as well as regression analyses independent of smoking habits. The results obtained revealed that the threshold of Pb-B to increase ALA-U was 25.1-35.0 µg/dL based on the significant elevation point of the prevalence of over-reference ALA-U and 16.2-22.3 µg/dL from a 3rd degree regression equation.

    Conclusions: We proposed a threshold of Pb-B to increase ALA-U of 20 µg/dL and a biologically acceptable value of ALA-U of 1 mg/L, corresponding to the threshold.

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  • Constanze Leineweber, Claudia Bernhard-Oettel, Constanze Eib, Paraskev ...
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12203
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: Earlier studies suggest that imbalance between effort and reward at work associates with exhaustion. Others have found that exhaustion increases turnover intentions; an important precursor of actual turnover that also associates with counterproductive work behaviors. Few, however, have studied the associations between effort-reward imbalance (ERI) and employees’ intentions to leave their current employment, and whether exhaustion is underpinning that relationship. Here, we investigate the mediating role of exhaustion in the effort-reward imbalance - turnover intentions relationship.

    Methods: Data from three waves covering a time span of four years from the Swedish Longitudinal Occupational Survey of Health (SLOSH) were analysed using structural equation modeling. Cross-lagged mediation analyses were conducted to estimate if associations from ERI to subsequent turnover intentions were mediated by exhaustion. Other causal directions (direct and reversed direct effects, reversed mediation) were also examined.

    Results: A direct path from ERI T1 to turnover intentions T2 was found, but not from ERI T2 to turnover intentions T3. Additionally, results showed that ERI at time points T1/T2 associated significantly with exhaustion two years later (T2/T3). Also, exhaustion at T1 showed a small but statistically significant direct association with turnover intentions at T2 (no association was found between exhaustion T2 and turnover intentions T3). A small, but statistically significant indirect effect from ERI to turnover intentions was found (estimate 0.005; 95% CI 0.002-0.010).

    Conclusions: Providing a good balance between effort and reward for workers is essential to protect employee health and help retain employees in the organization.

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  • Wanhyung Lee, Jongin Lee, Hyoung-Ryoul Kim, Yu Min Lee, Dong-Wook Lee, ...
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12204
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: We examined whether the effect of long working hours on the risk of developing cardiovascular disease (CVD) differs depending on individual risk factors.

    Methods: Seven-year follow-up data were extracted from the 2009 to 2016 waves of the Korea Health Panel Survey. Physician's diagnosis or medication for hypertension, diabetes, dyslipidemia, and obesity were included as chronic disease status. Smoking, drinking alcohol, and exercise levels were considered as lifestyle behavior. Hazard ratios were calculated using the Cox regression models to evaluate the risk of CVD related to chronic diseases and unhealthy behavior, based on working hour groups, after adjusting for other covariates. The interactive effects of long working hours with or without chronic diseases and unhealthy behavior on CVD were assessed using the relative excess risk due to interaction and attributable proportion measures.

    Results: There was a statistically significant interaction between long working hours and chronic diseases within the population, especially among male participants (P-value for interaction <.01 and .03, respectively). There were no significant interactions between unhealthy behavior and long working hours.

    Conclusions: Long working hours and chronic disease have a synergistic negative effect on the risk of CVD.

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  • Hirosuke Takahashi, Masako Nagata, Tomohisa Nagata, Koji Mori
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12205
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: The working-age population is rapidly declining in Japan, so the government has adopted “health and productivity management” (HPM). This policy initiative aims to encourage corporations to view health promotion activities as an investment in their employees’ health. The objective of this study was to examine the association between organizational factors and knowledge of the organization's effectiveness and program participation levels, and to understand the factors that affect effectiveness of corporations’ activities.

    Methods: We used data from all corporations that completed the HPM Survey Sheets in 2018 (n = 1800). The explanatory variables were organizational factors: written company-wide policy, agenda item at management-level meetings, regular education for managers, and full-time occupational health staff. The outcome variables were knowledge of the corporation's status on the effectiveness indicators (employees’ exercise habits, risk for high blood pressure, visiting hospital after a health examination, and long-term sickness absences) and rates of participation in four areas (health education, exercise program, dietary program, and influenza vaccination). The associations between organizational factors and knowledge on effectiveness indicators and rates of program participation were analyzed using multiple logistic regression analysis.

    Results: All the organizational factors were related to knowledge of effectiveness indicators, but only some were associated with the program participation indicators in the model, including all explanatory variables.

    Conclusion: Enhancing organizational factors may lead to improvement of HPM programs and higher program participation among employees in corporations.

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  • SukhDev Mishra, Kamalesh Sarkar
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12200
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: Ergonomic hazards account for a substantial proportion of work-related diseases and injuries among hairdressers. Awkward posture during work, repetitive movements, prolonged standing, and long working periods to carry out work activities cause mechanical load on the joints and work-related musculoskeletal disorders (WMSDs). This study investigated the musculoskeletal problems among urban hairdressers and associated risk factors.

    Methods: This study investigates the prevalence of WMSDs among 768 study subjects (384 hairdressers and control subjects each) from Ahmedabad and New Delhi metropolis in India. Univariate statistical analysis was carried out along with 95% confidence interval for effect estimates.

    Results: Findings reveal that the nearly half of the hairdressers suffered from knee and foot pain (49.5%), followed by lower back pain (39.8%) and upper back pain (38.8%). The neck pain and shoulder pain were reported by more than 25% hairdressers. The odds of developing neck pain (OR = 2.04; 95% CI 1.37-3.06) and shoulder pain (OR = 1.85; 95% CI 1.25-2.73) were significantly higher than control. The female hairdressers were more likely to experience work-related musculoskeletal disorder (OR = 2.63; 95% CI 1.18-5.86) than male counterparts. Hairdressers within the age of 18-35 years had significantly higher occurrence of musculoskeletal disorders with longer duration of working hours at the workplace. Longer daily work hours (>12 hours) posed significantly higher risk (OR = 2.47; 95% CI 1.39-4.38) of experiencing MSD for hairdressers.

    Conclusion: A very large proportion of hairdressers suffered with work-related musculoskeletal disorders. The long daily working hours and gender of the hairdresser are associated with increased risk of developing WMSDs.

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  • Nishiyama Yoko, Yamato Hiroshi, Jiang Ying
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12199
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: Suppression of postprandial hyperglycemia may aid in preventing lifestyle-related diseases in working people. The present study aimed to identify the types and timings of exercises that can be performed by working people during a 60-minute lunch break that are effective in attenuating postprandial increases in blood glucose levels.

    Methods: Healthy working people aged 20 years and older were subjected to aerobic (AER) or resistance (RES) exercise before (Pre) and after (Post) lunch, assuming a 60-minute lunch break, with fixed 20-minute lunch and rest periods. These exercise sessions of 4 different patterns were performed by each participant. Serial measurements of blood glucose levels were obtained every 15 minute using a Flash Glucose Monitoring System.

    Results: Data were analyzed for 11 participants who completed the protocol. Our incremental area under the curve (IAUC) analysis indicated that the AER-Post condition was associated with the most significant hypoglycemic effect, followed by the AER-Pre condition. Although the RES-Post showed no significant difference, a decrease in the IAUC comparison is apparent. However, the RES-Pre condition exerted no acute effect on blood glucose levels.

    Conclusions: Workers may benefit from a 20-minute aerobic exercise period, following a 20-minute lunch and a 20-minute rest period, as this may help prevent progression to diabetes. Furthermore, performing 20-minute aerobic exercises prior to lunch may also attenuate postprandial increases in blood glucose levels. Therefore, if the lunch breaks are short, aerobic exercises are recommended before lunch.

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Brief Reports
  • Miyuki Hirata, Makiko Nakano, Akiyo Tanaka, Kazuyuki Omae
    Type: BRIEF REPORT
    2021 Volume 63 Issue 1 e12207
    Published: 2021
    Released: March 25, 2021
    JOURNALS OPEN ACCESS

    Objective: To clarify whether indium in serum (In-S) is an appropriate parameter for assessing accumulated indium concentration in the lungs (In-L).

    Methods: During our approximately 15-year Japanese cohort follow-up, five male indium-tin oxide (ITO) or/and indium trioxide-exposed workers underwent lung surgical procedures to treat lung diseases or to confirm a diagnosis of lung impairments. We measured In-L of these Cases 1-5 and were able to assess the relationship between In-L and the most recent In-S. Another 1 Japanese case (Case 6) exposed to indium trioxide and indium hydroxide was referred from an article.

    Results: Cases 1 and 3 had lung cancer, Case 2 suffered from recurrent pneumothorax, and Case 4 had interstitial pneumonia with mild emphysema. Case 5 had severe emphysema with pulmonary hypertension and underwent bilateral lung transplantation. In Cases 1-5, In-L and In-S ranged from 3.4 to 161.2 µg/g wet weight and 0.7 to 60.4 ng/mL, respectively, and In-L/In-S ratios ranged from 2484 to 4857. The slope of the single regression equation with zero intercept was 2767 and the correlation coefficient was 0.995. In contrast, Case 6 was extraordinarily outlying, but the reason is unclear.

    Conclusions: In-S is an excellent predictor for assessing indium load in the lungs in ITO or/and indium trioxide-exposed workers. However, number of cases was only five and not enough to authorize definite conclusion. It is desirable to add more cases to confirm our conclusion.

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  • Shinobu Tsurugano, Mariko Nishikitani, Mariko Inoue, Eiji Yano
    Type: BRIEF REPORT
    2021 Volume 63 Issue 1 e12209
    Published: 2021
    Released: May 25, 2021
    JOURNALS OPEN ACCESS

    Objective: The COVID-19 pandemic has caused devastating damage to employment globally, particularly among the non-standard workforce. The objective of this study was to identify the effects of the pandemic on the employment status and lives of working students in Japan.

    Methods: The Labour Force Survey (January 2019 to May 2020) was used to examine changes in students’ work situations. In addition, to investigate the economic and health conditions of university students during the pandemic, the Student Lifestyle Survey was conducted in late May 2020. This survey asked students at a national university in Tokyo about recent changes in their studies, work, and lives.

    Results: The number of working students reported in the Labour Force Survey has declined sharply since March 2020, falling by 780,000 (46%) in April. According to a survey of university students’ living conditions, 37% were concerned about living expenses and tuition fees, and a higher percentage of students who were aware of financial insecurity had poor self-rated health.

    Conclusion: Nearly half of working students have lost their jobs during the pandemic in Japan, which has affected their lives, studies, and health. There is a need to monitor the impact of economic insecurity on students’ studies and health over time, and to expand the safety net for disadvantaged students.

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Review Articles
  • Wen-Pei Chang, Yu-Xuan Peng
    Type: REVIEW ARTICLE
    2021 Volume 63 Issue 1 e12208
    Published: 2021
    Released: May 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: Work-related musculoskeletal disorders (WMSDs) are common occupational injuries for nurses. Furthermore, rotating and irregular shift work may exacerbate muscle tension and pain in nurses. The objective of this study was to examine the differences between fixed day shift (FDS) nurses and rotating and irregular shift (RS + IS) nurses in WMSDs using a systematic literature review and meta-analysis.

    Methods: Databases including PubMed, CINAHL, Cochrane Library, EBSCOhost, and Google Scholar were searched for relevant studies published between 2010 and 2020 using the target keywords.

    Results: This study obtained data on a total of 18 199 nurses, among which 12 786 comprised the RS + IS group and 5413 constituted the FDS group. The result of the heterogeneity test was Q = 79.27 (P < .001) and I squared = 57.11%, indicating that heterogeneity existed among the studies. Subgroup analyses were also conducted with four groups: neck pain (n = 1818), shoulder and upper limb pain (n = 2525), back pain (n = 11 962), and hip and lower limb pain (n = 1894). Significant differences were found between the RS + IS group and the FDS group with regard to back pain, with the forest plot presenting an odds ratio equaling 1.40 (95% CI: 1.19-1.64, P < .001).

    Conclusions: This meta-analysis indicated that RS + IS nurses are more likely to experience back pain associated with WMSD than are FDS nurses. The results can serve as a reference to the clinical management for work improvement and thereby reduce or prevent the adverse effects of rotating and irregular shift work on back pain experienced by nurses.

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Original Articles
  • Tomohiro Ishimaru, Yoshihisa Fujino
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12211
    Published: 2021
    Released: May 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: To address ongoing problems concerning population aging and labor shortages in Japan, employers have sought to improve work efficiency and labor productivity. However, it is unclear how presenteeism is affected by working styles in line with current corporate initiatives, such as reduced working hours, varied employment status, and flexible work arrangements. The purpose of this article was to investigate the association between work style and presenteeism.

    Methods: This cross-sectional study extracted data from employee profiles, employee attendance records, and a questionnaire in a large service sector company. Multiple linear regression was conducted to estimate the contributions of work style variables to the Work Limitations Questionnaire (WLQ) index score.

    Results: In total, 21 500 participants were eligible for analysis. The WLQ index was lower for those working < 35 h/week (adjusted regression coefficient [ARC]:−0.35%; 95% CI: −0.48 to − 0.21) and higher for those working 40-44 h/week or ≥ 45 h/week, compared with those working 35-39 h/week. The position of team manager was positively associated with the WLQ index, whereas senior manager (ARC: −1.44%; 95% CI: −1.71 to − 1.17) and part-time staff (ARC: −1.75%; 95% CI: −1.98 to − 1.52) positions were negatively associated with the WLQ index, compared with non-managers. Those who worked remotely had significantly lower WLQ index scores (ARC: −0.61%; 95% CI: −0.95 to − 0.27).

    Conclusions: Reduced working hours and flexible work arrangements were associated with lower work limitations, which imply presenteeism, although additional research is necessary to verify these results.

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  • Noritoshi Fukushima, Masaki Machida, Hiroyuki Kikuchi, Shiho Amagasa, ...
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12212
    Published: 2021
    Released: May 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: To compare physical activity (PA) and sedentary behavior (SB) levels during work time between those who work from home (WFH) and at workplaces (no WFH), and by WFH subgroups.

    Methods: This cross-sectional internet-based survey included 1239 workers (mean age [standard deviation], 44.7 [13.7] years; 59.2% men) living in the Tokyo Metropolitan Area. Time spent sitting (SB), standing (light-intensity PA; LPA), walking, and engaging in heavy labor (moderate-to-vigorous PA; MVPA) during work time was measured using the Work-related Physical Activity Questionnaire. Workers reported weekly WFH percentages (eg, 0% implies no WFH and 100% implies full WFH), and WFH percentages were categorized into no WFH (0% WFH) and WFH (1%-100% WFH) groups. The WFH group was further subcategorized into 1%-25%, 26%-50%, 51%-75%, and 76%-100% subgroups.

    Results: Overall, 494 workers (39.9%) worked from home. During working hours, SB time was longer in the WFH group than in the no WFH group (mean minutes [% working-time SB]: 335.7 vs 224.7 min [74% vs 50%]). Significantly shorter LPA and MVPA times (%) were reported in the WFH group than in the no WFH group (LPA, 59.6 vs 122.9 min [14% vs 29%]; MVPA, 55.3 vs 91.9 min [13% vs 22%], all P < .001). Among the WFH subgroups, longer SB time and shorter LPA and MVPA times were observed in the highest WFH group (WFH 76%-100%) than in the WFH 1%-25% and 26%-50% subgroups.

    Conclusions: Workers who telecommuted were less physically active and had longer sedentary during work time than those who worked at the workplaces.

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  • Sintaroo Watanabe, Yun-Shan Li, Yuya Kawasaki, Yuko Ootsuyama, Kazuaki ...
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12210
    Published: 2021
    Released: May 25, 2021
    JOURNALS OPEN ACCESS

    Objective: Oxidative stress is considered to cause lifestyle-related diseases, including cancer. Urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) is widely analyzed as an oxidative stress marker. We extensively scrutinized the relationships between 8-OHdG levels and lifestyle choices as carcinogenic factors.

    Methods: In this study, we investigated health examination results and working conditions affecting urinary 8-OHdG levels in 503 male workers.

    Results: The urinary 8-OHdG level was positively associated with high blood sugar and leanness in smokers. In addition, urinary 8-OHdG tended to increase with organic solvent or hydrochloric acid exposure, as well as long working hours. On the other hand, the urinary 8-OHdG level was negatively associated with high plasma LDL-cholesterol levels in non-smokers and anemia.

    Conclusion: According to the results, anemia decreased the oxidative stress, regardless of smoking status, while leanness or high blood sugar increased the oxidative stress in smokers, and the presence of plasma cholesterol contributed to the lower oxidative stress in non-smokers. Certain types of occupational exposure may cause oxidative stress. The measurement of urinary 8-OHdG at annual health checks may be a useful biomarker for preventing lifestyle- and work-related diseases.

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  • Chiung-Yu Peng, Hui-Min Hsieh, Meng-Yun Li, Lih-Jiun Liaw, Chao-Ling W ...
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12214
    Published: 2021
    Released: May 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: Occupational characteristics in the food and beverage service industry (FBSI) have been found to be associated with musculoskeletal disorders (MSDs). This study aimed to examine gender and site-specific incident risks of MSDs among FBSI workers in Taiwan using a national population-based database.

    Methods: We conducted a 15-year population-based cohort study among 224 506 FBSI workers in Taiwan using data from five large nationwide databases to estimate direct standardized incidence ratios (SIRs) for identifying specific MSDs related to overexertion and repetitiveness during work. Overall, MSDs risks were also investigated by gender, sub-industrial categories, and certificate types.

    Results: We found SIRs for overall MSDs for male and female workers of 1.706 (95% CI, 1.688-1.724) and 2.198 (95% CI, 2.177-2.219), respectively. Our findings indicate significantly increased WMSD risk for both men and women, including median/ulnar nerve disorders (ICD-9 354.0-354.2); spondylosis and allied disorders (ICD-9 721); intervertebral disc disorders (ICD-9 722); disorders of the back (ICD-9 724); peripheral enthesopathies and allied syndromes (ICD-9 726); synovium, tendon, and bursa disorders (ICD-9 727); and soft tissues of the peripheral system disorders (ICD-9 729). Food stall workers and workers with Chinese cuisine or baking licenses were at higher risk among sub-industrial categories and certificate types.

    Conclusion: This large-scale study revealed that FBSI workers were at higher risk for several MSDs than the general population. This information could help prioritize MSD problems and identify a high-risk population. Relevant policy and ergonomic improvements and interventions could be implemented for health promotion in this industry.

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  • Karin Nomasa, Naoko Oya, Yuki Ito, Takehito Terajima, Takahiro Nishino ...
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12218
    Published: 2021
    Released: May 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: The comprehensive detection of environmental chemicals in biospecimens, an indispensable task in exposome research, is advancing. This study aimed to develop an exposomic approach to identify urinary metabolites of organophosphate (OP) pesticides, specifically cadusafos and prothiofos metabolites, as an example chemical group, using an original metabolome dataset generated from animal experiments.

    Methods: Urine samples from 73 university students were analyzed using liquid chromatography-high-resolution mass spectrometry. The metabolome data, including the exact masses, retention time (tR), and tandem mass spectra obtained from the human samples, were compared with the existing reference databases and with our original metabolome dataset for cadusafos and prothiofos, which was produced from mice to whom two doses of these OPs were orally administered.

    Results: Using the existing databases, one chromatographic peak was annotated as 2,4-dichlorophenol, which could be a prothiofos metabolite. Using our original dataset, one peak was annotated as a putative cadusafos metabolite and three peaks as putative prothiofos metabolites. Of these, all three peaks suggestive of prothiofos metabolites, 2,4-dichlorophenol, 3,4,5-trihydroxy-6-(2,4-dichlorophenoxy) oxane-2-carboxylic acid, and (2,4-dichlorophenyl) hydrogen sulfate were confirmed as authentic compounds by comparing their peak data with both the original dataset and peak data of the standard reagents. The putative cadusafos metabolite was identified as a level C compound (metabolite candidate with limited plausibility).

    Conclusions: Our developed method successfully identified prothiofos metabolites that are usually not a target of biomonitoring studies. Our approach is extensively applicable to various environmental contaminants beyond OP pesticides.

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Review Articles
  • Somkene Igboanugo, Philip L. Bigelow, John G. Mielke
    Type: REVIEW ARTICLE
    2021 Volume 63 Issue 1 e12219
    Published: 2021
    Released: May 25, 2021
    JOURNALS OPEN ACCESS

    Background and Objectives: Much of the research surrounding firefighter health has concerned the hazards intuitively associated with the occupation, such as physical, thermal, and chemical risks. However, an additional aspect of their work environment, psychosocial stressors, has begun to attract a growing level of attention. Work-related psychosocial stress may best be described as mental and emotional strain caused by a combination of workplace events and characteristics, and the objective of our review was to identify the health outcomes associated with these stressors in firefighters.

    Methods: A systematic review was performed of studies reporting on the psychosocial stressors and the associated health outcomes experienced by firefighters. Data sources included the MEDLINE, PsychInfo, and CINAHL databases.

    Results: Twenty-nine studies met the inclusion criteria. Upon analysis, we found that firefighters experienced a range of psychosocial stressors (including interpersonal conflict and concerns over organizational fairness) and observed that these stressors were associated with a number of health-related outcomes that could be arranged into six areas: depression-suicidality, non-depressive mental health problems, burnout, alcohol use disorders, sleep quality, and physiological parameters and somatic disorders.

    Conclusion: Our findings strongly suggest that work-related psychosocial stressors can affect the health and well-being of those in the fire service, and highlight that interventions meant to address these psychosocial risk factors should focus upon promoting self-esteem, enhancing self-efficacy, and strengthening social support.

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Letters To The Editor
Review Articles
  • Milad Abbasi, Behnaz Pourrajab, Mohammad Osman Tokhi
    Type: REVIEW ARTICLE
    2021 Volume 63 Issue 1 e12217
    Published: 2021
    Released: May 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: Occupational noise-induced hearing loss (NIHL) due to industrial, military, and other job -related noise exposure can cause harmful health issues to occupied workers, but may also be potentially preventable. Vitamins/antioxidant have been studied as therapeutic strategies to prevent and/or delay the risks of human diseases as well as NIHL .So, this study was conducted to systematically review the protective effects of vitamins/antioxidants on occupational NIHL.

    Methods: Online databases including PubMed/Medline, Scopus, Web of Science, EMBASE, Science Direct, and Google Scholar were systematically searched up to 12 January 2021. Based on 6336 potentially relevant records identified through the initial search in the databases, 12 full-text publications were retrieved, one of which can be viewed as two separate trials, because it has studied the effects of two different antioxidants (ginseng and NAC) on NIHL, separately.

    Results: A review of the studies shows that vitamin B12, folic acid, and N-acetylcysteine (NAC) have a considerable protective effect on NIHL. However, these protective effects are not yet specified in different frequencies. The findings regarding the protective effects of other antioxidants are inconsistent in this field.

    Conclusion: Vitamin B12, folic acid, and NAC may have a protective effect as an antioxidant on reducing occupational hearing loss. For a conclusive evidence of vitamin/antioxidant protective therapies, future studies with precise criteria for noise exposure and similar outcome parameters are required.

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Editorial
Original Articles
  • Satoru Kanamori, Naoki Kondo, Tomoko Takamiya, Hiroyuki Kikuchi, Shige ...
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12216
    Published: 2021
    Released: May 25, 2021
    JOURNALS OPEN ACCESS

    Objectives: The purpose of this study was to examine the relationship between social participation (type/pattern) and mortality according to company size of the longest-held job among older men in Japan who have worked in the company.

    Methods: Longitudinal data from the Japan Gerontological Evaluation Study were used in this study. Functionally independent individuals aged 65 years and older in Japan were surveyed. Work and community organizations (local community, hobbies, and sports) were used as social participation. A Cox proportional hazards model was used to calculate mortality hazard ratios.

    Results: Analysis was carried out on 19 260 participants. A total of 2870 deaths occurred during the 6-year follow-up period. Those in companies with 49 or fewer employees had the highest prevalence of work participation and the lowest participation in any community organization. Regardless of company size, the mortality risk was significantly lower for participants in any social participation (eg, the hazard ratio for participation in a hobby organization among those with a company size of 49 employees or fewer was 0.74, 95% CI: 0.65-0.85) compared to nonparticipants whose company size was 49 or fewer employees.

    Conclusions: In Japan, although older men who have worked for small companies may have fewer benefits, their social participation may reduce their mortality risks. To avoid increasing health inequalities, it is necessary to create an environment in which they are more likely to participate in social activities.

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  • Bibha Dhungel, Tomoe Murakami, Koji Wada, Stuart Gilmour
    Type: ORIGINAL ARTICLE
    2021 Volume 63 Issue 1 e12215
    Published: 2021
    Released: May 25, 2021
    JOURNALS OPEN ACCESS

    Objective: We aimed to analyse age-standardised mortality trends in Japan among blue- and white-collar male workers aged 25-64 years, by major causes of mortality from 1980 to 2015.

    Methods: Five-yearly mortality data were extracted from occupation-specific vital statistics maintained by the Japanese Ministry of Health, Labour and Welfare. A time series study was conducted among employed men aged 25-64 years. Age-standardised mortality trends by occupational category were calculated separately for all cancers, ischaemic heart disease, cerebrovascular disease and suicide. Poisson regression analysis was performed to analyse mortality trends by occupational category for each cause.

    Results: Mortality rates for all cancers and ischaemic heart disease were higher among white-collar workers than blue-collar workers throughout the 35-year study period. The gap in the mortality rates for all four causes of death among blue- and white-collar workers widened in 2000 after Japan's economic bubble burst in the late 1990s. Simultaneously, suicide mortality rates among white-collar workers increased sharply and have remained higher than among blue-collar workers.

    Conclusions: White-collar male workers in Japan have a higher risk of mortality than male blue-collar workers. However, despite substantial differences, significant progress has been made in recent years in reducing mortality across all occupations in Japan.

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