Industrial Health
Online ISSN : 1880-8026
Print ISSN : 0019-8366
ISSN-L : 0019-8366
Volume 59, Issue 4
Displaying 1-8 of 8 articles from this issue
Original Article
  • Gurmail S PADDAN, Michael C LOWER
    2021 Volume 59 Issue 4 Pages 204-219
    Published: March 11, 2021
    Released on J-STAGE: September 09, 2021
    Advance online publication: March 11, 2021

    The insertion losses of four pairs of earmuffs, including one noise-excluding headset, were measured in one-third octave bands in a diffuse broadband noise field using a head-like acoustic test fixture. The acoustic test fixture contained realistic ear simulators with microphones at the eardrum positions. The insertion losses were measured (i) with the earmuffs on their own, (ii) with the earmuffs worn over an anti-flash hood, and (iii) for one earmuff, with the earmuff worn under the hood. The other three earmuffs could not be fitted under the hood. The insertion loss of the anti-flash hood on its own was also measured. Wearing an anti-flash hood under the earmuffs greatly reduced the protection against noise, by 20–23 dB at high frequencies, by 17–20 dB at middle frequencies, by 12–16 dB at low frequencies, and by 16–20 dB overall. Only one earmuff was slim enough to fit under an anti-flash hood. Wearing an anti-flash hood over this earmuff had only a marginal effect on the earmuff insertion loss, of the order of 1 dB. If anti-flash hoods could be designed to fit over other types of earmuffs and headsets, the protection of these earmuffs and headsets would be virtually maintained.

    Download PDF (2407K)
    2021 Volume 59 Issue 4 Pages 220-228
    Published: March 10, 2021
    Released on J-STAGE: September 09, 2021
    Advance online publication: March 10, 2021

    The present study focuses on social stressors at work and the development of physical symptoms in social workers on a daily basis. In a seven-day diary study it was anticipated that daily rumination functions as a mediator, linked to additional daily physical symptoms in individuals. Before and after work, 81 social workers completed daily questions on social stressors, rumination, and physical symptoms. Multilevel analyses of up to 391 daily measurements revealed that more intense social stressors predicted more rumination, as well as physical symptoms. Rumination anteceded higher physical symptoms. A test of the indirect effects showed a significant indirect path from social stressors at work via rumination to physical symptoms. Hence, it was found that social stressors and rumination contribute to the ongoing health crisis in the social work profession. These findings advance our understanding of the stress mechanisms in social work, as well as point to individual and organizational aspects that occupational health prevention programs should consider.

    Download PDF (1255K)
  • Kuniyoshi TOYOSHIMA, Takeshi INOUE, Akiyoshi SHIMURA, Jiro MASUYA, Yot ...
    2021 Volume 59 Issue 4 Pages 229-238
    Published: July 14, 2021
    Released on J-STAGE: September 09, 2021
    Advance online publication: July 14, 2021

    Insomnia, job-related stress, and cognitive dysfunction affect the mental health of workers. However, the relationships among sleep reactivity, job-related stress, and subjective cognitive dysfunction in workers remains not fully understood. Therefore, this study seeks to investigate the relationships among these variables in Japanese adult workers. In total, 536 adult workers in Japan were evaluated using the Japanese version of Ford Insomnia Response to Stress Test, Brief Job Stress Questionnaire, and Cognitive Complaints in Bipolar Disorder Rating Assessment to assess sleep reactivity, job-related stress, and subjective cognitive function, respectively. Path analysis was also carried out. The results of the path analysis showed that sleep reactivity significantly influenced on subjective cognitive dysfunction directly and indirectly via job stressors and stress reaction. Our results may not be generalizable to underage workers because only adult workers were included, which is a limitation of this study. The results of the present study suggest that job-related stress mediates the effect of sleep reactivity on subjective cognitive dysfunction in Japanese adult workers. This underscores the need to evaluate the mediating effect of job-related stress in addressing the subjective cognitive dysfunction associated with insomnia in workers.

    Download PDF (1617K)
  • Yukiko FUETA, Mitsuo HINOUE, Hazuki NOGUCHI, Mizuki MATSUNO, Toru ISH ...
    2021 Volume 59 Issue 4 Pages 239-248
    Published: July 10, 2021
    Released on J-STAGE: September 09, 2021
    Advance online publication: July 13, 2021

    Previously, we reported that prenatal exposure to 1-bromopropane (1-BP) causes the accumulation of bromide (Br-) in the brain of rat pups. Here, we aimed to investigate the effects of Br- accumulation in rat pups prenatally exposed to 1-BP vapor. Dam rats were exposed to 1-BP (400 or 700 ppm; 1-BP group) by inhalation, or to NaBr (20 mM; Br- group) in drinking water during gestation days 1–20. We also analyzed pentylenetetrazole (PTZ, 60 mg/kg, ip)-induced behavioral changes in pups prenatally exposed to 1-BP or Br- on postnatal day (PND) 14. PTZ-induced epileptic convulsions were inhibited in both 1-BP (700 ppm) and Br- groups. The inhibition of neuronal excitability induced by Br- was evaluated electrophysiologically using the hippocampal slices obtained from PND14–16 pups. PTZ (2 mM) failed to induce epileptiform discharge in the presence of 1.2 mM Br- in the slices obtained from the control group. However, it induced epileptiform discharge following the removal of Br-, by perfusing artificial cerebrospinal fluid into the slices obtained from the Br- group. Our results indicate that Br- accumulates in the brain of neonatal rat pups prenatally exposed to 1-BP vapor suppressed neuronal excitability.

    Download PDF (1898K)
  • Jungsun PARK, Yangho KIM
    2021 Volume 59 Issue 4 Pages 249-259
    Published: August 05, 2021
    Released on J-STAGE: September 09, 2021
    Advance online publication: August 05, 2021

    We examined the association of weekly working hours with poor psychological wellbeing in Korean workers and the moderating effect of employment status. This secondary analysis examined data from the fifth Korean Working Conditions Survey (2017). There were 30,108 waged employees and 14,459 self-employed individuals. The two groups were compared using a moderated regression model with Hayes’ PROCESS macro for SPSS. The self-employed had a greater mean age than the waged employees. Higher percentages of the self-employed had short weekly working hours (<40), excessively long weekly working hours (≥60), and poor psychological well-being. After controlling for age, gender, education, monthly income, and occupational class, the interaction between weekly working hours and employment status on psychological well-being was significant (p<0.001). Among the self-employed, the well-being score was lowest in the short working hour group (<40 h/week), highest in the long working hour (48–59 h/week) groups, and intermediate in the excessively long working hours (≥60 h/week) group. For waged employees, psychological wellbeing was the greatest in the short working hour group and decreased continuously as the number of weekly working hours increased. In conclusion, employment status (employee vs. self-employed) moderated the relationship between weekly working hours and psychological well-being.

    Download PDF (1185K)
Field Report
  • Kazuyuki IWAKIRI, Midori SOTOYAMA, Masaya TAKAHASHI, Xinxin LIU
    2021 Volume 59 Issue 4 Pages 260-271
    Published: April 03, 2021
    Released on J-STAGE: September 09, 2021
    Advance online publication: April 03, 2021

    In Japan, the practice of the no-lift policy, which states that care recipients should be lifted with care equipment rather than by human power, has been increasing since around 2014. The purpose of this study was to examine whether severe low back pain (LBP) risk factors in caregivers changed between 2014 and 2018. A questionnaire survey targeting administrators and caregivers working in care facilities for the elderly was conducted in 2014 and 2018. A total of 612 facilities and 2,712 caregivers responded to the questionnaires in 2014, and 504 facilities and 3,478 caregivers completed the questionnaires in 2018. The percentage of caregivers who experienced severe LBP did not differ significantly between 2014 (37.3%) and 2018 (38.3%). However, the number of facilities that introduced care equipment for transfer increased in 2018. Moreover, the number of participants who received training on care methods and using care equipment increased. Lifting a facility resident using human power and taking an unsuitable posture were associated with severe LBP in 2014, but only taking an unsuitable posture was associated with severe LBP in 2018. As taking an unsuitable posture remains to be a primary risk factor for severe LBP, it needs to be addressed in care facilities.

    Download PDF (1248K)
Country Report
    2021 Volume 59 Issue 4 Pages 272-282
    Published: March 02, 2021
    Released on J-STAGE: September 09, 2021
    Advance online publication: March 02, 2021

    To examine the fit testing of elastomeric half face-piece respirators (EHRs), a total of 41 candidates were randomly assigned into seven EHRs equipped with organic vapor (OV) cartridges which were commonly used in the Iranian industrial workplaces. The qualitative fitting into the facial dimensions was assessed using the Allegro Isoamyl Acetate fit test kit. While the studied EHRs showed very low passing fit testing rates, the 3M, AoSafety (Medium), and AoSafety (Large) had the highest passing rates with 22.0%, 14.60%, and 9.76%, respectively. The AoSafety (All sizes) delivered a higher passing fit test rate than the 3M brand (29.30 vs. 22.0%). The one size fits all respirators including the DUO and Climax showed lower proportions of passing fit tests compared with AoSafety three-size system brands (2.40% and 4.90% vs. 29.30%). Low fit test passing rates were determined among different respirators. The respirators with various sizes and styles had more opportunities for different wearers to pass the fit test than single size models. The initial and annual fit testing requirements shall be developed by local government. Also, the manufacturers are required to pay attention to respirator features and subject characteristics during the production to obtain satisfactory protection for the end-users.

    Download PDF (1942K)