Journal of Occupational Health
Online ISSN : 1348-9585
Print ISSN : 1341-9145
ISSN-L : 1341-9145
Current issue
Displaying 1-27 of 27 articles from this issue
Issue Information
Original Articles
  • Anli Yue Zhou, Mark Hann, Maria Panagioti, Mumtaz Patel, Raymond Agius ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12311
    Published: 2022
    Released on J-STAGE: March 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: This study aims to develop a comprehensive list of stressors relevant to junior doctors and will also report findings exploring the associations between burnout and stressors, which include work and non-work-related stressors as well as pandemic-related stressors.

    Methods: An anonymous online questionnaire was sent to 1000 randomly selected junior doctors in the North-West of England. The questionnaire included 37 questions on general and pandemic-specific stressors, and the Maslach Burnout Inventory Health Services Survey. The main outcomes of interest were junior doctor ratings of stressors and scores for burnout (emotional exhaustion [EE], depersonalisation [DP], and personal accomplishment [PA]). Stepwise regression analysis was undertaken to assess associations between stressors and burnout.

    Results: In total, 326 responses were collected (response rate = 33%). Of the top 10 stressors rated by junior doctors, 60% were related to the pandemic. Multiple stressors were found to be associated with the burnout dimensions. Fatigue (β = .43), pandemic-related workload increase (β = .33), and feeling isolated (β = .24) had the strongest associations with EE, whereas fatigue (β = .21), uncertainty around COVID-19 information (β = .22) and doing unproductive tasks (β = .17) had the strongest associations with DP. Working beyond normal scope due to COVID-19 (β = −.26), not confident in own ability (β = −.24) and not feeling valued (β = −.20) were found to have the strongest associations with PA.

    Conclusions: Junior doctors experience a combination of general stressors and additional stressors emerging from the pandemic which significantly impact burnout. Monitoring these stressors and targeting them as part of interventions could help mitigating burnout in junior doctors.

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  • Takashi Sunami, Ryuhei So, Hironobu Ishii, Eiji Sadashima, Takefumi Ue ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12312
    Published: 2022
    Released on J-STAGE: March 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: To assess the effectiveness of a web-based brief intervention (BI) program to record daily drinking among people with problem drinking in workplace settings.

    Methods: A two-armed, parallel-group, randomized controlled trial were conducted at six workplaces in Japan. After obtaining written consent to participate in the study, workers with an Alcohol Use Disorders Identification Test (AUDIT) score of 8 or higher were randomly assigned into two groups. The participants allocated to the intervention group recorded their daily alcohol consumption for 4 weeks using the program, while those allocated to the control group received no intervention. Outcome measures included the amount of alcohol consumption in past 7 days using the Timeline Follow-Back method in the program at baseline, 8th week, and 12th week and written AUDIT score at baseline and 12th week.

    Results: Hundred participants were assigned to either the intervention group (n = 50) or control group (n = 50). The results of two-way repeated measures ANOVA showed a statistically significant interaction between the group and the week factors in the two primary outcomes (number of alcohol-free days, total drinks) and secondary outcomes (AUDIT score) (p = .04, .02, and .03, respectively). The between-group effect sizes (Hedges' g; 95% CI) of the outcomes at 12th week were 0.53; 0.13-0.93 (total drinks), 0.44; 0.04-0.84 (AUDIT score), 0.43; 0.03-0.83 (number of alcohol-free days).

    Conclusions: The web-based BI program for problem drinking was considered to be effective in reducing alcohol consumption and the AUDIT score in workplace settings.

    Editor's pick

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  • Makoto Okawara, Tomohiro Ishimaru, Seiichiro Tateishi, Ayako Hino, May ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12313
    Published: 2022
    Released on J-STAGE: March 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: This study examined the relationship between interruption to routine medical care during the coronavirus disease 2019 pandemic and sickness presenteeism among workers in Japan.

    Methods: A cross-sectional study using data obtained from an internet monitor questionnaire was conducted. Interruption to medical care was defined based on the response “I have not been able to go to the hospital or receive treatment as scheduled.” The fraction of sickness presenteeism days in the past 30 days was employed as the primary outcome. A fractional logit model was used for analysis to treat bounded data.

    Results: Of the 27 036 participants, 17 526 (65%) were workers who did not require routine medical care, 8451 (31%) were using medical care as scheduled, and 1059 (4%) experienced interrupted medical care. The adjusted odds ratio (aOR) of sickness presenteeism was significantly higher among workers who experienced interrupted medical care (3.44; 95% confidence interval [CI]: 3.04-3.89) than those who did not require routine medical care. In terms of symptoms, the highest aOR was observed among workers with mental health symptoms (aOR: 5.59, 95% CI: 5.04-6.20).

    Conclusions: This study suggests the importance of continuing necessary treatment during a pandemic to prevent presenteeism.

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  • Stijn Keyaerts, Lode Godderis, Ellen Delvaux, Liesbeth Daenen
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12314
    Published: 2022
    Released on J-STAGE: March 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: Knowledge is lacking on the interaction between fear of movement (FOM) and work-related physical and psychosocial factors in the development and persistence of musculoskeletal disorders (MSDs).

    Methods: In this cross-sectional study, 305 healthcare workers from several Belgian hospitals filled out a questionnaire including sociodemographic factors, work-related factors (social support, autonomy at work, workload, and physical job demands), FOM, and MSDs for different body regions during the past year. Path analysis was performed to investigate (1) the association between the work-related factors, FOM and MSDs, and (2) the moderating role of FOM on the association between the work-related factors and MSDs among healthcare workers.

    Results: Complaints were most frequently located at the neck-shoulder region (79.5%) and lower back (72.4%). Physical job demands (odds ratio [OR] 2.38 and 95% confidence interval [CI] 1.52-3.74), autonomy at work (OR 1.64 CI [1.07-2.49]) and FOM (OR 1.07 CI [1.01-1.14] and OR 1.12 CI [1.06-1.19]) were positively associated with MSDs. Healthcare workers who experienced high social support at work (OR 0.61 CI [0.39-0.94]) were less likely to have MSDs. Fear of movement interacted negatively with workload (OR 0.92 CI [0.87-0.97]) and autonomy at work (OR 0.94 CI [0.88-1.00]) on MSDs.

    Conclusions: Work-related physical and psychosocial factors as well as FOM are related to MSDs in healthcare workers. FOM is an important moderator of this relationship and should be assessed in healthcare workers in addition to work-related physical and psychosocial factors to prevent or address MSDs.

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  • Sami Salo, Heidi Hurri, Toni Rikkonen, Reijo Sund, Heikki Kröger, Joon ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12316
    Published: 2022
    Released on J-STAGE: March 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: Occupational physical loading has been reported to be associated with intervertebral disc degeneration. However, previous literature reports inconsistent results for different vertebral levels. The aim of our study was to investigate the association between lumbar disc degeneration (LDD) at different vertebral levels and the self-reported physical loading of occupation.

    Methods: The study population consisted of 1,022 postmenopausal women and was based on the prospective Kuopio Osteoporosis Risk Factor and Prevention (OSTPRE) study cohort. The severity of LDD was graded from T2-weighted MRI images using the five-grade Pfirrmann classification. Five intervertebral levels (L1-L2 to L5-S1) were studied (total 5110 discs). The self-rated occupational physical loading contained four groups: sedentary, light, moderate, and heavy.

    Results: The heavy occupational physical loading group had higher odds for severe LDD at the L5-S1 vertebral level (OR 1.86, 95% CI: 1.19-2.92, = .006) in comparison with the sedentary work group. A clear trend of increasing disc degeneration with heavier occupational loading was also observed at the L5-S1 level. Age, smoking, and higher body mass index (BMI) were associated with more severe LDD. Leisure-time physical activity at the age of 11-17 years was associated with less severe LDD. Controlling for confounding factors did not alter the results.

    Conclusions: There appears to be an association between occupational physical loading and severe disc degeneration at the lower lumbar spine in postmenopausal women. Individuals in occupations with heavy physical loading may have an increased risk for work-related disability due to more severe disc degeneration.

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Brief Reports
  • Tomohisa Nagata, Masako Nagata, Ayako Hino, Seiichiro Tateishi, Akira ...
    Article type: BRIEF REPORT
    2022 Volume 64 Issue 1 Article ID: e12317
    Published: 2022
    Released on J-STAGE: March 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: The purpose of this study was to investigate the relationships of workers being diagnosed with coronavirus disease 2019 (COVID-19) and being identified as close contacts of infected persons with unemployment in Japan.

    Methods: This was a prospective cohort study using questionnaires about COVID-19 administered to Japanese workers. A baseline survey conducted on December 22-25, 2020, was used to determine history of being diagnosed with COVID-19 or being identified as a close contact of an infected person. Unemployment since the baseline survey was ascertained with a follow-up survey on February 18 and 19, 2021. The odds ratios (ORs) of unemployment were estimated using a multilevel logistic model with adjusted covariates nested in prefecture of residence.

    Results: Women (n = 8771) accounted for 44% of the total sample (n = 19 941), and the mean age was 48.0 years. In terms of unemployment because of negative reasons, the multivariate analysis showed that the OR of unemployment associated with being diagnosed with COVID-19 was 2.40 (95% CI: 1.15-5.01) and that the OR associated with being identified as a close contact was 0.98 (95% CI: 0.31-3.11).

    Conclusions: There is an association between workers being diagnosed with COVID-19 and unemployment. The reason is not clear, but if the unemployment is unwanted by the individual, workplace adjustment may help prevent unwilling unemployment.

    Editor's pick

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Original Articles
  • Dong-Hee Koh, Ju-Hyun Park, Sang-Gil Lee, Hwan-Cheol Kim, Hyejung Jung ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12318
    Published: 2022
    Released on J-STAGE: March 25, 2022
    JOURNAL OPEN ACCESS

    Objective: Exposure to ultraviolet (UV) radiation from sunlight induces the production of essential vitamin D, whereas overexposure to sunlight leads to skin cancer. Sunlight exposure has been measured using questionnaires, dosimeters, and vitamin D levels. Several studies have measured vitamin D in the working population; however, these studies were limited to certain occupations such as farmers and construction workers. In the present study, we evaluated sunlight exposure using blood vitamin D as an exposure surrogate across industries and occupations.

    Methods: The Korea National Health and Nutrition Examination Survey (KNHANES) is a nationwide study representing the Korean population. We analyzed data from KNHANES between 2008 and 2009. We examined the association between vitamin D levels and pertinent personal, seasonal, residential, and occupational factors. Furthermore, we developed a multiple regression model with factors other than occupational factors (industry and occupation) and obtained residual values. We computed the third quartile (Q3) of the residuals and then calculated the fractions exceeding the Q3 level for each combination of industry and occupation.

    Results: Age, sex, body mass index, year, season, latitude, living area, living in an apartment, industry, and occupation were significantly associated with vitamin D levels. Based on the exceeding fraction, the armed forces showed the highest exceeding fraction level of 0.71.

    Conclusions: Our results present the high exposure groups to sunlight across industries and occupations. Our results may provide a source for prioritizing occupational groups with a high risk of adverse health effects from sunlight exposure.

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  • Natsu Sasaki, Takahiro Tabuchi, Ryo Okubo, Tomohiro Ishimaru, Mayumi K ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12319
    Published: 2022
    Released on J-STAGE: March 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: Association between employment contract (temporary vs. permanent) and suicidal ideation (persistent suicidal ideation [i.e., with onset before COVID-19] or newly developed under COVID-19 pandemic) was examined using a nationally representative cross-sectional study in Japan.

    Methods: An Internet survey was conducted from August to September 2020. The participants’ inclusion criteria for this study were as follows: (i) 20-65 years old, (ii) employees (excluding self-employed, students, retired, housewives, and unemployed). The associations of suicidal ideation with the employees’ factors were analyzed using the multinomial logistic regression model, adjusting for covariates (sex, age, marital status, education, company size, industries, and a history of psychiatric disease).

    Results: Of total 12 249 participants, 72.4% were permanent and 27.6% were temporary employees. The prevalence was 8.5% for persistent suicidal ideation and 3.2% for newly developed suicidal ideation in the COVID-19 pandemic. Temporary employment was significantly associated with persistent suicidal ideation (adjusted odds ratio [aOR] = 1.36 [95% confidence interval, CI: 1.16-1.59]; P < .001), but not associated with newly developed suicidal ideation (aOR = 1.10 [0.85-1.42]; P = .457) after adjusting the covariates. Sensitivity analysis showed temporary employment was significantly associated with persistent suicidal ideation only in women. Newly developed suicidal ideation was significantly higher among participants of a young age, employees in drinking/eating/hotel business industry, and those having a history of psychiatric disease than among the counterparts.

    Conclusions: Working on a temporary employment contract was associated with persistent suicidal ideation under conditions of COVID-19 outbreaks in Japan. However, the result showed no significant difference in newly developed suicidal ideation. Further longitudinal study will be needed to examine the risk of being employed on an unstable occupational contract in the prolonged pandemic.

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Occupational Health and Safety In The World
  • Ángel Arturo López-González, Zoe Manzanero, Hilda María González San M ...
    Article type: OCCUPATIONAL HEALTH AND SAFETY IN THE WORLD
    2022 Volume 64 Issue 1 Article ID: e12320
    Published: 2022
    Released on J-STAGE: May 25, 2022
    JOURNAL OPEN ACCESS

    Background and objective: Cardiovascular diseases are the leading cause of morbidity and mortality worldwide, with a greater incidence in the most disadvantaged social classes. In this study, we aimed to evaluate the level of cardiovascular risk in cleaning workers.

    Methods: This was a descriptive, cross-sectional study in 46.632 cleaning workers (40.169 women and 6.463 men). Thirty-one different scales related to cardiovascular risk were studied (14 assessing overweight and obesity, 5 determining the risk of nonalcoholic fatty liver disease, 5 scales of cardiovascular risk, 4 atherogenic indices, and 3 scales of metabolic syndrome, among others). The results obtained were divided between personnel who perform their cleaning tasks in the hotel and catering industry and those in other sectors.

    Results: The prevalence of obesity and arterial hypertension in cleaning workers was over 20% in both sexes. A similar amount was observed in moderate or high values on the REGICOR (Registre GIroní del COR) scale. More than 15% presented metabolic syndrome according to the NCEP ATPIII (National Cholesterol Education Program-Adult Treatment Program III) criteria, while over 10% of women and 20% of men had a high risk of nonalcoholic fatty liver disease assessed with the fatty liver index.

    Conclusion: Cardiovascular risk is higher, in both sexes, in the group of cleaning workers who work in companies other than hotels.

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Original Articles
  • Xin Liu, Weimin Dang, Hui Liu, Yao Song, Ying Li, Weixian Xu
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12321
    Published: 2022
    Released on J-STAGE: May 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: Plasma chromogranin A (CgA) may play a critical role on linking work stress to health outcomes. The aim of our study was to investigate the associations between work stress and plasma CgA levels in healthy workers without chronic diseases.

    Methods: The study included 260 healthy workers from EHOP study. Work stressors were assessed by the Chinese version of the 23-item ERI-Q questionnaire. Plasma CgA and catestatin levels were measured by ELISA kits. The demographic characteristics were collected from medical records.

    Results: Among the final 260 subjects including 173 males (66.5%) and 87 females (33.5%), the average age was 37.6 ± 10.6 years old. Effort, overcommitment, and ERI were positively associated with plasma CgA level, respectively (r = 0.267, 0.319, and 0.304, all p < .001), while reward was negatively associated with CgA level (r = −0.237, p < .001). The workers with high effort, overcommitment, or ERI had significantly higher plasma CgA levels, while the workers with high rewards had significantly lower plasma CgA levels. The workers with both high overcommitment and high ERI had highest plasma CgA levels. In the linear regression analysis, after adjustment for confounders, effort, overcommitment, and ERI were respectively positively related to plasma CgA, while reward negatively related to plasma CgA. The associations between work stress and plasma catestatin was not significant. The ratio of CgA and catestatin was associated with work stress.

    Conclusions: Work stress is associated with plasma CgA which may be play a crucial role on the pathway from chronic work stress to cardiovascular diseases.

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Brief Reports
  • Annina Ropponen, Aki Koskinen, Sampsa Puttonen, Jenni Ervasti, Mika Ki ...
    Article type: BRIEF REPORT
    2022 Volume 64 Issue 1 Article ID: e12322
    Published: 2022
    Released on J-STAGE: May 25, 2022
    JOURNAL OPEN ACCESS

    Objective: To investigate the association of hospital physicians’ working hours and on-call shifts with the risk of occupational injuries.

    Methods: In this nested cohort study of 556 Finnish hospital physicians, we linked electronic records from working-hour and on-call duty payroll data to occupational injury data obtained from the Finnish Workers’ Compensation Center for the period 2005-2019. We used a case-crossover design with matched intervals for a 7-day ‘case window’ immediately prior to occupational injury and a ‘control window’ 7 days prior to the beginning of the case window, and analyzed their associations using conditional logistic regression models.

    Results: We noted 556 occupational injuries, 281 at the workplace and 275 while commuting. Having three to four long (>12 h) work shifts on the preceding 7 days was associated with a higher probability of an occupational injury (odds ratio [OR] 2.14, 95% confidence interval [CI] 1.11, 4.09), and the OR for three to four on-call shifts was 3.54 (95%CI 2.11, 5.92) in comparison to having none of these work shift types. A higher number of several consecutive working days was associated with a higher probability of injury in a dose-response manner. Moreover, increasing weekly working hours was associated with an increased likelihood of injury (OR 1.03, 95%CI 1.01, 1.04), whereas the number of normal (≤12 h) work shifts reduced this likelihood (OR 0.79, 95%CI 0.64, 0.98).

    Conclusions: Our findings suggest that accumulated working-hour load, as opposed to single, very long (>24 h) work shifts, may increase the risk of occupational injury among hospital physicians.

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Original Articles
  • Joonho Ahn, Jongin Lee, Hyoung-Ryoul Kim, Yu Min Lee, Tae-Won Jang, Do ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12326
    Published: 2022
    Released on J-STAGE: May 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: Several studies have reported health or safety risk of temporary agency workers (TAW). Since most of the studies are just cross-sectional studies, we intended to identify the risk of occupational injury in TAW, using longitudinal study design.

    Methods: The Korea Health Panel 2009-2018 data were used in the study. For the statistical analysis of this study, we used a panel logit model to identify the risk of occupational injury in TAW compared to direct contract workers (DCW).

    Results: There was no significant difference in risk of occupational injury between TAW and DCW among the overall population (adjusted OR 0.920, 95% CI 0.600-1.411). However, there was a significant increase in occupational injury in women (adjusted OR 2.134, 95% CI 1.092-4.170) and the “19-34” age group (adjusted OR 2.744, 95% CI 1.103-6.825) of TAW.

    Conclusions: This study provides evidence for vulnerable groups such as women and younger age groups in the relationship between TAW and occupational injury.

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  • Keisuke Suzuki, Madoka Okamura, Yasuo Haruyama, Shiho Suzuki, Tomohiko ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12328
    Published: 2022
    Released on J-STAGE: May 25, 2022
    JOURNAL OPEN ACCESS

    Objective: Multiple chemical sensitivity (MCS) is a form of chemical intolerance in which various systemic symptoms are triggered by exposure to a variety of chemical substances. Although migraine has been associated with central sensitivity syndrome, the relationship between MCS and migraine has not been studied. We assessed the frequency of MCS and its related factors in patients with migraine.

    Methods: We performed a cross-sectional study that included 95 patients (14 M/81 F; age, 45.4 ± 12.4 years) out of 100 consecutive patients with migraine from our outpatient headache clinic. MCS was defined as having a combination of Q1 ≥ 30, Q3 ≥ 13, and Q5 ≥ 17 on the quick environment exposure sensitivity inventory (QEESI; Japanese version). Central sensitization inventory-A scores >40 were considered an indication of central sensitization. Headache-related disability and psychological distress were evaluated with the Migraine Disability Assessment score (MIDAS) and Kessler Psychological Distress Scale (K6), respectively.

    Results: MCS was identified in 20% of patients with migraine; however, none had previously been diagnosed with MCS. The MCS-positive group had higher rates of photophobia, osmophobia, visual aura, sensory aura, and central sensitization and higher MIDAS and K6 scores than the MCS-negative group. A logistic regression analysis showed that osmophobia, sensory aura, and central sensitization were significant contributors to MCS.

    Conclusion: We showed that MCS was observed in 20% of patients with migraine, and our study results may indicate a possible association of MCS with central sensitization and hypersensitivity-related symptoms in patients with migraine.

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Corrigendum
Original Articles
  • Kimiyo Mori, Chikage Nagano, Kimie Fukuzawa, Natsuko Hoshuyama, Riho T ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12323
    Published: 2022
    Released on J-STAGE: May 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: This study examined whether a fan-attached jacket (FAJ) may mitigate the heat strain in hot or humid environment.

    Methods: Nine healthy men engaged in 60-min sessions on a bicycle ergometer (4 metabolic equivalents [METs] workload) in hot-dry (40°C and 30% relative humidity) and warm-humid (30°C and 85% relative humidity) environments. Both are equivalent to an approximately 29°C wet-bulb globe temperature. The experiment was repeated-once wearing an ordinal jacket (control condition) and once wearing a long-sleeve FAJ that transfers ambient air at a flow rate of 12 L/s (FAJ condition)-in both environments.

    Results: Increases in core temperatures in hot-dry environment were not statistically different between control and FAJ; however, that in the warm-humid environment were significantly different between control and FAJ (0.96 ± 0.10°C and 0.71 ± 0.11°C in rectal temperature, P < .0001; and 0.94 ± 0.09°C and 0.61 ± 0.09°C in esophageal temperature, P < .0001). Changes in heart rate were different between control and FAJ in both environments (62 ± 3 bpm and 47 ± 7 bpm, P < .0001 in hot-dry environment; and 61 ± 3 bpm and 46 ± 5 bpm, P < .0001 in the warm-humid environment) and decrease of %weight change was different in hot-dry environment (1.59 ± 0.12% and 1.25 ± 0.05%, P = .0039), but not in the warm-humid environment.

    Conclusions: Wearing a FAJ may mitigate heat strain both in hot or humid environments.

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  • Sihao Lin, Cheng Chung Tsai, Xudong Liu, Zhenyi Wu, Xianzhe Zeng
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12330
    Published: 2022
    Released on J-STAGE: May 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: This study is to evaluate the efficacy of participatory ergonomic (PE) intervention on musculoskeletal disorders (MSDs) and work ability among young dental professionals in China.

    Methods: A cluster randomized controlled trail was conducted during 2015-2016. Twenty-nine departments from five hospitals in the South of China were randomized into intervention (14 departments) and control (15 departments), with individuals of 125 and 138 dental professionals, respectively. Main participatory ergonomic interventions involved work posture, repetitive motions, tool usage, work break relaxation and work time re-arrangement with total 235 ergonomic changes in the trail. Individual ergonomic risk exposure was assessed by investigator's observation using quick exposure check (QEC). Work ability index (WAI) and MSDs were collected by questionnaires at baseline, and every 3 months during the 1-year follow-up.

    Results: Follow-up rate was 91% and 96% for the intervention and control group, respectively. Significant reductions in ergonomic risk exposure and MSD prevalence on six anatomic sites were found in the PE group during the different follow-up stages. WAI scores improved by 1.1 (95% CI 0.43, 1.89) after the 9-month intervention. Compared to the control, the PE participants significantly reduced MSDs on neck (OR = 2.93, 95% CI: 1.25, 4.03) and wrists/hands (OR = 2.33, 95% CI: 1.08, 4.21), marginally increased WAI scores by 0.53 (95% CI: −0.02, 1.56) due to the interventions.

    Conclusion: PE intervention is effective in reducing ergonomic risk exposure and MSDs on neck and wrists/hands among young dental professionals. PE ought to be offered in the early dental career for preventing MSDs.

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  • Michael Rosander, Morten Birkeland Nielsen
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12327
    Published: 2022
    Released on J-STAGE: May 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: To prospectively investigate the reciprocal associations between tiredness at work (TAW) and exposure to bullying behaviors and to determine the role of conflict management climate (CMC) as a moderator of these associations.

    Methods: A two-wave national probability sample of employees in Sweden (18 months between waves, 921 participated at both waves) measuring TAW, workplace bullying, and CMC. Structural equation modelling was used to test four hypotheses about the longitudinal associations between feeling tired at work and bullying, and CMC as a moderator for the two directions.

    Results: In the analyses of cross-lagged effects, tiredness was significantly associated with an increase in subsequent bullying (β = 0.08, P = .01). Exposure to bullying was not associated with changes in tiredness. CMC moderated the association between tiredness and subsequent bullying (β = −0.13, 95% CI [−0.19, −0.08]), showing an increased risk of exposure to bullying behaviors following tiredness when CMC was low and decreased risk when CMC was high.

    Conclusions: TAW is a risk factor for subsequent bullying. Finding ways to help employees to reduce tiredness not only will help them perform better at work but also reduce the risk of them becoming targets of bullying. A strong CMC can act as a buffer if a tired person provoke aggression from co-workers.

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  • Ryutaro Matsugaki, Tomohiro Ishimaru, Ayako Hino, Keiji Muramatsu, Tom ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12329
    Published: 2022
    Released on J-STAGE: May 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: This study examined the relationship between frequency of working from home and low back pain (LBP), considering the quality of work environment.

    Methods: The study was based on a cross-sectional internet-based survey. Of 33 302 respondents, data from 12 774 desk workers were retained for analysis. We used a 0-10 numerical rating scale to assess LBP. Work environment was assessed using five subjective questions. Mixed-effects logistic regression nested by city level was used to analyze the relationship between frequency of working from home and LBP, stratified by work environment condition.

    Results: The prevalence of LBP was 21.0%. Among those reporting a poor work environment, as opposed to almost never working from home, the multivariate odds ratio (OR) of LBP were as follows: working from home less than 1 day per week: OR = 1.25, 95% CI: 0.89-1.76, p = .190; 2-3 days per week: OR = 1.58, 95% CI: 1.16-2.16, p = .004; and 4 or more days per week: OR = 1.82, 95% CI: 1.38-2.40, p < .001. By contrast, among those reporting a good work environment, the OR of LBP did not increase as the frequency of working from home increased.

    Conclusions: The relationship between LBP and frequency of working from home was found to vary with the quality of the work environment; more specifically, LBP was associated with frequency of teleworking in a poor work environment. This study suggests that employers should give more support to their employees in promoting a good work environment to prevent LBP. (Words: 240/250).

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  • Kanami Tsuno, Akihito Shimazu, Katerine Osatuke, Kyoko Shimada, Emiko ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12332
    Published: 2022
    Released on J-STAGE: May 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: This study aimed to examine the reliability and validity of the Japanese version of the eight-item CREW Civility Scale which measures workplace civility norms and compare the civility scores among various occupations.

    Methods: A longitudinal study included all employees in a social care organization (N = 658) and a cross-sectional study included all civil servants in one city (N = 3242) in Japan. Structural validity was tested through confirmatory factor analyses (CFA). Construct validity was assessed through Pearson's correlations of civility with other variables. Internal consistency was assessed by Cronbach's alpha and 1-year test-retest reliability was assessed by the Intraclass Correlation Coefficient (ICC).

    Results: The results of CFA showed an acceptable level of model fit (TLI =0.929; CFI =0.949; and SRMR =0.034). CREW Civility Scale scores were significantly positively correlated with supervisor support, co-worker support, and work engagement, while significantly negatively correlated with incivility, workplace bullying, intention to leave, and psychological distress, which were consistent with our hypotheses. Cronbach's alpha coefficient was 0.93 and ICC was 0.52. Younger, high-educated, and managerial employees and, childminder/nursery staff reported higher civility. High school graduates and respondents who did not graduate from high school, part-time employees, nurses, paramedical staff, and care workers reported lower civility.

    Conclusions: The Japanese version of the CREW Civility scale is a reliable, valid measure of civility, appropriate for Japanese workplaces as well as for use in multi-national studies alongside other existing versions of this scale in English, Portuguese and Farsi.

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Brief Reports
  • Naoko Inoue, Mitsutoshi Takaya
    Article type: BRIEF REPORT
    2022 Volume 64 Issue 1 Article ID: e12333
    Published: 2022
    Released on J-STAGE: May 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: A simple check test method was designed to confirm whether a 2,4-dinitrophenylhydrazine (DNPH) filter for formaldehyde can be used to measure other compounds.

    Methods: Sample mixtures containing the same concentrations of formaldehyde, acetaldehyde, and acetone were spiked to the DNPH-filter, extracted, and then measured using high performance liquid chromatography with photodiode array detector (HPLC-PDA). The amounts of DNPH-derivatives versus the amounts of spiked samples were then plotted.

    Results: When the amount of DNPH << the total amount of spiked samples, the amount of DNPH-derivatives was formaldehyde > acetaldehyde >> acetone. This order corresponded to the relative rate constants for the reaction. Therefore, this study confirmed that acetone was not collected at the formaldehyde sampling rate.

    Conclusions: This check test easily measured the reaction rate order and can be used as a simple test to determine whether other samples can be measured by the analytical methods used for the specified sample.

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Original Articles
  • Shinya Yamaguchi, Miho Sato, Naomi Sumi, Yoichi M. Ito, Peter C. Winwo ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12325
    Published: 2022
    Released on J-STAGE: July 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: Shift-work nurses are at a higher risk of inadequate recovery from fatigue and developing maladaptive fatigue with significant health consequences. Therefore, it is necessary to monitor fatigue and recovery levels with a reliable scale. We investigated psychometric properties of the Japanese version of the Occupational Fatigue Exhaustion Recovery scale (OFER-J) for shift-work nurses.

    Methods: Japanese shift-work nurses responded to self-administered questionnaires at baseline (n = 942) and one month later (n = 334). The confirmatory factor analysis (CFA) and exploratory factor analysis (EFA) were conducted to verify the structural validity and the correlation analysis and one-way analysis of variance were conducted to test the construct and discriminative validity. Cronbach's alpha coefficient, intra-class correlation coefficient (ICC), and smallest detectable change (SDC) were calculated to assess reliability.

    Results: The CFA showed high correlations between the factors and whilst the goodness-of-fit of the three-factor model was suboptimal, it was in an acceptable range. Most modifications included the error covariance of the Acute Fatigue (AF) and Intershift Recovery (IR) items. The EFA showed that Chronic Fatigue (CF) and AF were not clearly separated, indicating that the two AF items dropped out. Construct and discriminative validity were also well indicated. Cronbach's alpha coefficients were 0.75-0.85. Only CF showed sufficient reproductivity (ICC = 0.74). The SDC for CF, AF, and IR was 14.0, 17.1, and 18.7, respectively.

    Conclusions: The validity and reliability of the OFER-J were verified as acceptable for shift-work nurses. The OFER-J could contribute to a data-based approach to fatigue management in nursing management practice.

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  • Chihiro Watanabe, Yusuke Konno, Ayako Hino, Masako Nagata, Keiji Muram ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12331
    Published: 2022
    Released on J-STAGE: July 25, 2022
    JOURNAL OPEN ACCESS

    Objective: This study examined the association between increased alcohol consumption and telecommuting, comparing employees who expressed a preference for telecommuting and those who did not.

    Methods: We conducted an internet monitor survey. Responses from 20 395 of the 33 302 participants were included in the final sample. Participants were asked about their desire for and frequency of telecommuting, and about changes in alcohol consumption under the COVID-19 pandemic. Data were analyzed by logistic regression analysis.

    Results: The ratio of increased drinking in those who telecommuted at least once a week was significantly different (OR = 1.29, 95% CI 1.16-1.43, p < .001). The ratio of increased drinking in participants for whom telecommuting was not preferred was significantly different (OR = 1.08, 95%CI 1.02-1.14, p = .002). Since the interaction term was significant in preliminary analysis, stratification was performed. Participants who telecommuted despite preferring not to do so reported significantly increased alcohol consumption, as revealed by a multivariate analysis (OR = 1.53, 95% CI 1.18-2.00, p < .001). Participants who expressed a preference for telecommuting showed no such increase (OR = 1.12, 95% CI 0.98-1.27, p = .074).

    Conclusions: Under the COVID-19 pandemic, telecommuting that involves a mismatch with employee preference for way of working may be a new risk factor for problematic drinking.

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Brief Reports
  • Shuhei Izawa, Nanako Nakamura-Taira, Toru Yoshikawa, Rie Akamatsu, Hir ...
    Article type: BRIEF REPORT
    2022 Volume 64 Issue 1 Article ID: e12334
    Published: 2022
    Released on J-STAGE: July 25, 2022
    JOURNAL OPEN ACCESS

    Objective: During the Coronavirus disease 2019 (COVID-19) pandemic, social isolation and impaired social interaction could be the factors that cause mental health problems. This study investigated the association between conversation time in daily life and mental health among Japanese employees.

    Methods: In August 2021, a web-based cross-sectional survey was conducted with 1000 Japanese employees. Weekly conversation time was assessed in four domains (family members, friends, someone in the workplace, and others), and mental health was assessed using the Japanese version of the Kessler Psychological Distress Scale (K6 scale). Weekly total conversation time was calculated, and participants were assigned to one of the four conversation time categories based on quantile values to investigate the associations with poor mental health (K6 ≥ 13).

    Results: The logistic regression analyses revealed that participants with short conversation times (<3.5 h per week) had poorer mental health compared to those with long conversation times (> 21.0 h per week), even after adjusting for confounders (OR = 2.48 [95% CI 1.31-4.71]). For the exploratory analyses of conversation time for each domain, the associations of short conversation time in the workplace with poor mental health was most robust (OR =2.02 [95% CI 1.13-3.63]).

    Conclusions: Japanese employees with conversation time of <3.5 h per week (i.e., 30 min per day) had poor mental health. During the COVID-19 pandemic, people have largely limited opportunities to have conversations with others, but a certain level of conversation time might be required to maintain mental health.

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  • Kazuhiro Watanabe, Akiomi Inoue, Hisashi Eguchi, Noboru Iwata, Yuko Od ...
    Article type: BRIEF REPORT
    2022 Volume 64 Issue 1 Article ID: e12335
    Published: 2022
    Released on J-STAGE: July 25, 2022
    JOURNAL OPEN ACCESS

    Objective: This study aimed to obtain suggestions for new organizational-level item pools that companies could utilize to accomplish management philosophy and mission statements in the context of survey and work environment improvements for the national Stress Check Program.

    Methods: A qualitative study was conducted using unsupervised learning. A large amount of text data related to management philosophy and mission statements were collected, that is, management messages described on the websites of all companies listed on the Tokyo Stock Exchange. For the main analysis, topic modeling was performed on the nouns from the management messages using Latent Dirichlet Allocation (LDA) to build a model consisting of 10 latent topics, each represented by a group of the 10 most frequently reoccurring nouns. Each group of nouns was qualitatively summarized based on the topic model.

    Results: In total, 22 524 nouns were extracted from the management messages of 3575 companies. A topic model consisting of 10 latent topics was constructed using the LDA. The suggestion for new item pools included new technologies, business plans/strategies, company shareholders, health/happiness/wealth, profits/sales, development of society, a sustainable society, safety and security, customer/consumer satisfaction, corporate social responsibility, fairness, transparency, and human rights.

    Conclusion: The suggestions for potential item pools were derived from management philosophy and mission statement that are not covered in the existing survey. The suggestions could be useful for motivating employers to implement work environment improvement. Future studies need to make definite items and investigate whether they correlate to job stressors and mental health among workers.

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Original Articles
  • Juho Sim, Byungyoon Yun, Jin-Ha Yoon, Jiho Lee, Juyeon Oh, Ara Cho, Su ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12336
    Published: 2022
    Released on J-STAGE: July 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: A rest time of less than 11 h taken by a shift worker between shifts is defined as quick return (QR). QR is shown to decrease sleep time by virtue of decreasing rest time, diminishing sleepiness and exhaustion, and increasing the number of sick days taken by employees. Therefore, in this multicenter retrospective study, the association between QR and the incidence of insomnia was established using the night-shift questionnaire from the Korean Workers Health Examination-Common Data Model.

    Methods: Three hospitals collected the night-shift profiles and baseline demographic data of 33 669 workers between January 2015 and December 2017. The most recent date of examination was used for participants who had been examined multiple times at the same institution. We used multiple logistic regression to calculate the odds ratios (ORs) and 95% confidence intervals (CIs). The pooled ORs were estimated using combined results from the three institutions.

    Results: The proportion of men was higher than that of women in the QR group at each institution. The pooled ORs were computed using combined data from the three institutions. Workers who reported a QR had the highest risk of sleeplessness (OR, 1.21; 95% CI, 1.12-1.31) compared to those workers who reported a slow return, after adjusting for possible confounders.

    Conclusions: A substantial correlation was established between QR and insomnia using the CDM approach and data from multiple centers. This study may serve as a foundation for developing guidelines to enhance the health of shift workers and prevent occupational accidents.

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  • Masayoshi Zaitsu, Takumi Takeuchi, Masaaki Zaitsu, Akiko Tonooka, Tosh ...
    Article type: ORIGINAL ARTICLE
    2022 Volume 64 Issue 1 Article ID: e12340
    Published: 2022
    Released on J-STAGE: July 25, 2022
    JOURNAL OPEN ACCESS

    Objectives: We sought to examine occupational disparities in tumor grade and cytosolic expression of high-mobility group box-1 (HMGB1) among renal cell cancer (RCC) patients.

    Methods: This retrospective study included 318 RCC patients with complete information on occupation and pathology in Kanagawa Cancer Registry (KCR). Longest-held occupations were grouped into manual workers (e.g., manufacturing, construction) versus “others.” Odds ratios (OR) and 95% confidence intervals (CI) for high-grade histology were estimated by logistic regression, adjusted for age and sex. We also examined a sub-sample of 74 low-grade RCC inpatients to estimate the OR for positive cytosolic HMGB1 expression in manual workers, adjusting for age, sex, and other available covariates.

    Results: High-grade tumors were more prevalent in manual workers compared to other occupations: 23.0% (14/61) versus 10.9% (28/257, p = .01) with an adjusted OR of 2.28 (95% CI, 1.11-4.69). In the sub-sample of low-grade RCCs, positive cytosolic HMGB1 expression was more prevalent in manual workers compared to other occupations: 71.4% (10/14) versus 38.3% (23/60, p = .03) with a sex- and age-adjusted OR of 3.76 (95% CI, 1.03-13.7).

    Conclusions: Manual workers are associated with increased risks of high-grade renal cell tumors and cytosolic HMGB1 expression.

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