Objective: The Japanese government established the Pneumoconiosis Law in 1960 to protect health and promote the welfare of workers engaged in dust-exposed works. This article describes Japanese practice in workplace health management as regulated by the Pneumoconiosis Law to reduce pneumoconiosis in Japan. Methods: We collected information addressing pneumoconiosis and the health care of dust-exposed workers. We included all types of scientific papers found through a PubMed search as well as official reports, guidelines, and relevant laws published by the Ministry of Health, Labour and Welfare (MHLW) of Japan and other academic institutions. Results: In the past, pneumoconiosis has been a major cause of mortality and morbidity for Japanese workers engaged in dust-exposed work. The Pneumoconiosis Law introduced a system of pneumoconiosis health examination and health supervision to protect workers' health. According to the periodic pneumoconiosis health examination reports in Japan, the prevalence of pneumoconiosis fell from the highest reported figure of 17.4% in 1982, where 265,720 examinations were conducted, to 1% in 2013 in which 243,740 workers were examined. The number of new cases of pneumoconiosis dropped from 6,842 cases in 1980 to 227 cases in 2013. One hundred and seventy two workers were diagnosed as having pneumoconiosis complications in 1980; however, the number fell to five in 2013. Conclusion: After reaching its peak in the 1980s, pneumoconiosis and its complications fell each year. The achievement of Japanese pneumoconiosis prevention can be credited to a comprehensive provision for worker health, regulated by a thorough legal framework.
Objectives: Allyl nitrile (3-butenenitrile) occurs naturally in the environment, in particular, in cruciferous vegetables, indicating a possible daily intake of the compound. There is no report on actual health effects of allyl nitrile in humans, although it is possible that individuals in the environment are at a risk of exposure to allyl nitrile. However, little is known about its quantitative assessment for the environment and bioactivity in the body. This study provides a review of previous accumulated studies on allyl nitrile. Methods: Published literature on allyl nitrile was examined for findings on toxicity, metabolism, risk of various cancers, generation, intake estimates, and low-dose effects in the body. Results: High doses of allyl nitrile produce toxicity characterized by behavioral abnormalities, which are considered to be produced by an active metabolite, 3,4-epoxybutyronitrile. Cruciferous vegetables have been shown to have a potential role in reducing various cancers. Hydrolysis of the glucosinolate sinigrin, rich in cruciferous vegetables, results in the generation of allyl nitrile. An intake of allyl nitrile is estimated at 0.12 μmol/kg body weight in Japan. Repeated exposure to low doses of allyl nitrile upregulates antioxidant/phase II enzymes in various tissues; this may contribute to a reduction in neurotoxicity and skin inflammation. These high and low doses are far more than the intake estimate. Conclusion: Allyl nitrile in the environment is a compound with diverse bioactivities in the body, characterized by inducing behavioral abnormalities at high doses and some antioxidant/phase II enzymes at low doses.
Objectives: In this study, we focused on the qualitative and quantitative differences of the lung lesions induced by single or multiple intratracheal administration of nickel oxide nanoparticles (NiO). Methods: Male rats were randomized into groups receiving intratracheal administrations in a single dose or two to four divided doses of 2 mg/kg/bw. Bronchoalveolar lavage fluid (BALF) analyses were performed at 3 and 28 d post-dose. Histopathological analyses were performed at 28 and 91 d post-dose. Results: BALF analyses revealed pulmonary injury, inflammation, and increases in the parameters indicating processing the foreign material in all the NiO-treated groups. Histopathological analyses showed the phagocytosis of NiO by alveolar macrophages, degeneration and necrosis of alveolar macrophages, and inflammatory responses. In the comparison between single and multiple administrations, the trend for stronger toxicity effects was observed after multiple application at 3 d post-dose, while the obvious toxicity effects were also seen in case of single administration. No particular differences of lung lesions depending on the frequency of administration at 28 and 91 d post-dose were evident. Conclusion: Intratracheal NiO administration induced strong toxic response thoroughly even by single administration. Therefore, single administration was concluded to be applicable to assess the inhalation toxicity of nanomaterials and can be used in the screening test.
Aim: This study was designed to clarify the effects of active rest, with a focus on the practice of short-time group exercise by workplace units, on personal relationships, mental health, physical activity, and work ability among workers. Methods: Fifty-nine white-collar workers (40 males and 19 females) performed our active rest (short-time exercise) program, which consists of warm-up, cognitive functional training, aerobic exercise, resistance training and cool-down for 10 minutes per day, 3 times per week during their lunch breaks for 10 weeks. Participants from a workplace unit were randomly allocated to the intervention (five workplaces, n=29) or control groups (six workplaces, n=30). The participants' anthropometric measurements, and their Profile of Mood States (POMS) 2, Brief Job Stress Questionnaire (BJSQ), physical activity levels and Work Ability Index were examined at the baseline and after the 10-week intervention. Results: After 10 weeks, physical activity levels, especially the time spent in moderate and vigorous intensity, increased in the intervention group (p<0.05). The items of "vigor-activity" and "friendliness" improved in POMS 2, while "vigor," "interpersonal stress," "support from superiors, colleagues, and family/friends," and "job satisfaction" improved in BJSQ in the intervention group (p<0.05). In the intervention group, the number of exercise participation was positively correlated with the change in "vigor-activity" in POMS 2 (r=0.467, p=0.011). Conclusions: These results suggest that the practice of active rest by workplace units is important for improving personal relationships, mental health, and physical activity among workers.
Objectives: The purpose of this study was to investigate the permeation of the low-volatile solvent limonene through different disposable, unlined, unsupported, nitrile exam whole gloves (blue, purple, sterling, and lavender, from Kimberly-Clark). Methods: This study utilized a moving and static dextrous robot hand as part of a novel dynamic permeation system that allowed sampling at specific times. Quantitation of limonene in samples was based on capillary gas chromatography-mass spectrometry and the internal standard method (4-bromophenol). Results: The average post-permeation thicknesses (before reconditioning) for all gloves for both the moving and static hand were more than 10% of the pre-permeation ones (P≤0.05), although this was not so on reconditioning. The standardized breakthrough times and steady-state permeation periods were similar for the blue, purple, and sterling gloves. Both methods had similar sensitivity. The lavender glove showed a higher permeation rate (0.490±0.031 μg/cm2/min) for the moving robotic hand compared to the non-moving hand (P≤0.05), this being ascribed to a thickness threshold. Conclusions: Permeation parameters for the static and dynamic robot hand models indicate that both methods have similar sensitivity in detecting the analyte during permeation and the blue, purple, and sterling gloves behave similarly during the permeation process whether moving or non-moving.
Objectives: Sleep disturbances are related to somatic and mental disorders, industrial accidents, absenteeism, and retirement because of disability. We aimed to identify health-related behaviors associated with subjective sleep insufficiency in Japanese workers. Methods: This cross-sectional study included 5,297 employees (mean age: 43.6±11.3 years; 4,039 men). Multiple logistic regression analysis was used to identify health-related behaviors associated with subjective sleep insufficiency. Results: Overall, 28.2% of participants experienced subjective sleep insufficiency. There was a significant difference between the genders in the proportion of participants with subjective sleep insufficiency (male: 26.4%; female: 34.3%; p<0.001). Multiple logistic regression analysis revealed that being a female or ≥40 years, experiencing a weight change of ≥3 kg during the preceding year, not exercising regularly, not walking quickly, and eating a late-evening or fourth meal were associated with subjective sleep insufficiency. After stratifying by gender, age ≥40 years, not exercising regularly, and eating a late-evening or fourth meal were significantly associated with subjective sleep insufficiency in both genders. Not walking quickly, experiencing a weight change, and eating quickly were positively associated with subjective sleep insufficiency only for males. Females who did not engage in physical activity were more likely to have experienced subjective sleep insufficiency, but this relationship was not observed in males. Conclusions: The results indicated that certain health-related behaviors, specifically not exercising regularly and nocturnal eating habits, were associated with subjective sleep insufficiency in a group of Japanese workers.
Objectives: Work ability is a crucial occupational health issue in health care settings where a high physical and psychosocial work capacity is required and a high risk of disabling injuries and illnesses is predictable. This study aims to examine the association between the work ability index (WAI) and individual characterizations, workload, fatigue, and diseases among intensive care units' (ICUs') nurses. Methods: The study sample included 214 nurses selected by a random sampling method from a target population consisting of 321 registered nurses working in eight ICUs. Multiple linear regression analysis was used to test the association between WAI scores and each of the independent variables. Results: Results of multivariate analysis revealed a strong and negative association between WAI scores and diseases (B=-5.82, 95% CI=-7.16, -4.48, P<0.001). Among the studied individual characterizations, body mass index (BMI) was significantly and inversely associated with WAI scores. A significant and negative association was also found between WAI scores and dimensions of MFI-20, such as general fatigue (B=-0.31, 95% CI=-0.53, -0.09, P=0.005) and physical fatigue (B=-0.44, 95% CI=-0.65, -0.23, P<0.001). From dimensions of workload, frustration (B=-0.04, 95% CI=-0.07, -0.02, P<0.001) and temporary demand (B=-0.04, 95% CI=-0.08, -0.0001, P=0.04) showed a negative and significant association with WAI scores, while performance showed a positive and significant association (B=0.04, 95% CI=0.01, 0.07, P=0.005). Conclusions: Based on the study findings, development of health care programs with the aim of setting up a healthy work environment characterized by a well-structured preventive attitude toward controlling diseases, and a well-designed organizational framework toward increasing the level of performance and motivation, reducing the level of fatigue, as well as reducing the workload, is necessary to promote work ability among ICUs' nurses.
Objectives: To examine whether disaster-related variables, in addition to known work-related risk factors, influence burnout and its subscales (exhaustion, cynicism, and lack of professional efficacy) among public servants who experienced a major disaster. Methods: Cross-sectional studies were conducted among public servants of Miyagi prefecture at 2 and 16 months after the Great East Japan Earthquake (n=3,533, response rate 66.8%); burnout was assessed at 16 months using the Japanese version of the Maslach Burnout Inventory-General Survey. We examined the relationships between burnout and its subscales with disaster-related variables at 2 months after the disaster, while controlling for age, gender, and work-related variables at 16 months after the disaster. Results: After controlling for age, gender, and work-related variables, a significant risk factor of burnout was having severe house damage. For the each subscale of burnout, living someplace other than their own house increased the risk of both exhaustion and cynicism, while handling residents' complaints did so only for exhaustion. Notably, workers from health and welfare departments showed an increased risk of burnout, exhaustion, and cynicism, but not lack of professional efficacy. Conclusions: The findings suggest that special attention is needed for workers with severe house damage to prevent burnout, as well as those who lived someplace other than their own house to prevent exhaustion and cynicism after a major disaster. Interventions directed at workers of the health and welfare department should focus more on limiting exhaustion and cynicism, rather than promoting professional efficacy.
Objectives: This study aims to determine (1) total dialkylphosphate (ΣDAP) levels, occupational knowledge and practice, DNA damage, AChE activity, and health symptoms in rice, corn, and double-crop farmers; (2) the association of health symptoms with ΣDAP levels, occupational knowledge and practice, DNA damage, and AChE activity in farmers; and (3) the prevalence of health symptoms between farmers and non-farmers. Methods: A cross-sectional study was conducted by interviewing as well as analyzing urine and blood samples during July to August 2014. Results: There were no differences in ΣDAP levels, AChE activity, and occupational knowledge and practice scores among all farmer groups. In terms of health symptoms related to ΣDAP, AChE activity, DNA damage, and occupational knowledge and practice, pesticide-related symptoms were determined, including breathlessness, chest pain, dry throat, numbness, muscle weakness, cramp, headache, dizziness, eye irritation, white/red rash, and white/red pimple, which were classified as respiratory, muscle, nervous, and epithelial symptoms. A remarkable finding was that farmers had a significantly higher prevalence of muscle weakness (odds ratio (OR)=3.79) and numbness (OR=3.45) as compared with non-farmers. Conclusion: Our findings, therefore, suggest that a long-term low-level exposure to organophosphates (OPs) may be associated with an increasing prevalence of muscle symptoms. However, a further cohort study incorporating sensitive health outcomes and measurement of multiple pesticides monitoring on a larger scale is warranted.
Objectives: The main objective of this study is to examine the relationship between indicators of non-standard work arrangements, including precarious contract, long working hours, multiple jobs, shift work, and work-related accident absence, using a representative Belgian sample and considering several socio-demographic and work characteristics. Methods: This study was based on the data of the fifth European Working Conditions Survey (EWCS). For the analysis, the sample was restricted to 3343 respondents from Belgium who were all employed workers. The associations between non-standard work arrangements and work-related accident absence were studied with multivariate logistic regression modeling techniques while adjusting for several confounders. Results: During the last 12 months, about 11.7% of workers were absent from work because of work-related accident. A multivariate regression model showed an increased injury risk for those performing shift work (OR 1.546, 95% CI 1.074-2.224). The relationship between contract type and occupational injuries was not significant (OR 1.163, 95% CI 0.739-1.831). Furthermore, no statistically significant differences were observed for those performing long working hours (OR 1.217, 95% CI 0.638-2.321) and those performing multiple jobs (OR 1.361, 95% CI 0.827-2.240) in relation to work-related accident absence. Those who rated their health as bad, low educated workers, workers from the construction sector, and those exposed to biomechanical exposure (BM) were more frequent victims of work-related accident absence. No significant gender difference was observed. Conclusion: Indicators of non-standard work arrangements under this study, except shift work, were not significantly associated with work-related accident absence. To reduce the burden of occupational injuries, not only risk reduction strategies and interventions are needed but also policy efforts are to be undertaken to limit shift work. In general, preventive measures and more training on the job are needed to ensure the safety and well-being of all workers.
Objectives: We conducted a 6-year cohort study to evaluate the relationship between carbon disulfide (CS2) exposure and reductions in the motor and sensory nerve conduction velocity (MCV and SCV) of the median nerve. Methods: Study subjects at baseline included 432 exposed workers and 402 unexposed workers. Among the exposed workers, 145 workers terminated CS2 exposure during the follow-up period (ex-exposed workers). MCV and SCV were measured at baseline and followed up. CS2 personal exposure concentration was measured two times a year during a 6-year follow-up period and mean (range) CS2 exposure concentrations (ppm) were 5.96 (0.8-16.0) and 3.93 (0.6-9.9) in the exposed and ex-exposed workers, respectively. Results: Reductions in MCV during the follow-up period did not differ among the exposed, ex-exposed, and unexposed workers. Reduction in SCV (m/s) of the exposed workers (-4.47±3.94) was significantly larger than that of the unexposed (-3.38±3.97) and ex-exposed workers (-3.26±3.79). For SCV reduction, a partial multiple regression coefficient of (ex-exposed workers) / (unexposed workers) was significantly positive (+0.915, p < 0.01) after adjustment for confounding variables. Conclusions: This cohort study showed that 6-year CS2 exposure around a mean level of 6 ppm did not affect MCV reduction but induced significant SCV reduction beyond the influence of aging. The effect of CS2 on SCV around a mean exposure level of 4 ppm may be reversible, since it disappeared in the ex-exposed workers after CS2 exposure cessation for a mean period of 4.1 years.
Objectives: A new desorption method was investigated, which does not require toxic organic solvents. Efficient desorption of organic solvents from activated carbon was achieved with an ananionic surfactant solution, focusing on its washing and emulsion action. Methods: Isopropyl alcohol (IPA) and methyl ethyl ketone (MEK) were used as test solvents. Lauryl benzene sulfonic acid sodium salt (LAS) and sodium dodecyl sulfate (SDS) were used as the surfactant. Activated carbon (100 mg) was placed in a vial and a predetermined amount of organic solvent was added. After leaving for about 24 h, a predetermined amount of the surfactant solution was added. After leaving for another 72 h, the vial was heated in an incubator at 60°C for a predetermined time. The organic vapor concentration was then determined with a frame ionization detector (FID)-gas chromatograph and the desorption efficiency was calculated. Results: A high desorption efficiency was obtained with a 10% surfactant solution (LAS 8%, SDS 2%), 5 ml desorption solution, 60°C desorption temperature, and desorption time of over 24 h, and the desorption efficiency was 72% for IPA and 9% for MEK. Under identical conditions, the desorption efficiencies for another five organic solvents were investigated, which were 36%, 3%, 32%, 2%, and 3% for acetone, ethyl acetate, dichloromethane, toluene, and m-xylene, respectively. Conclusions: A combination of two anionic surfactants exhibited a relatively high desorption efficiency for IPA. For toluene, the desorption efficiency was low due to poor detergency and emulsification power.
Objective: To examine the effects of a new wearable type of lumbosacral support on low back pain. Methods: A total of 121 healthcare workers participated in this study. They were randomly allocated into the experimental and control groups and the former wore the support with signals of compression on the back by poor posture for the first 3 months. The control group remained on a waiting list for the first 3 months. Medical history, musculoskeletal symptoms, feeling in good posture, sleep habits, psychological distress, Roland-Morris Disability Questionnaire, and Somatosensory Amplification Scale (SSAS) were evaluated. The range of motion (ROM) in the shoulder and hip joints as well as spinal alignment were evaluated. Our primary concern was the difference in the change of low back pain measured by visual analog scale (VAS) between the two groups. Results: A total of 54 participants in the experimental and 53 participants in the control groups were analyzed. VAS and SSAS scores as well as lumbar spinal ROM in the experimental group significantly decreased. Low back pain (OR=0.401, 95% CI=0.168-0.954) and neck pain in the experimental group (OR=0.198, 95% CI=0.052-0.748) significantly decreased. Conclusions: The new lumbar support reduced VAS and SSAS scores, lumbar spinal ROM, low back pain, and neck pain. This new type of lumbar support reduced low back pain among healthcare workers.
Objectives: In a job site, a portable fan is often used to ventilate a confined space. When a portable fan is applied to such a space, the actual ventilation flow rate must be accurately estimated in advance because the safety level of contaminant and oxygen concentrations in the space will determine the ventilation requirements. When a portable fan is used with a flexible duct, the actual flow rate of the fan decreases due to the friction and duct bending loss of the duct. Intending to show the decline of a fan performance, the author conducted laboratory experiments and reported the quantitative effect of the friction and duct bending loss of a flexible duct to the flow rate of a portable fan. Methods: Four commercial portable fans of different specifications were procured for the experiments, and the decline of the performance of each portable fan due to the friction loss etc. of a connected flexible duct was investigated by measuring actual flow rate. Results: The flow rate showed an obvious decrease from the rated flow rate when a flexible duct was connected. Connection of a straight polyester flexible duct and a straight aluminum flexible duct reduced the flow rates to 81.2 - 52.9% and less than 50%, respectively. The flow rate decreased with an increase of the bend angle of the flexible duct. Conclusion: It is recommended that flow rate check of a portable fan should be diligently carried out in every job site.