Journal of Occupational Health
Online ISSN : 1348-9585
Print ISSN : 1341-9145
ISSN-L : 1341-9145
Volume 49, Issue 1
Displaying 1-10 of 10 articles from this issue
Original
  • Kuniyuki Niijima, Kazuhiko Enta, Hiroko Hori, Shunsuke Sashihara, Tets ...
    2007 Volume 49 Issue 1 Pages 1-8
    Published: 2007
    Released on J-STAGE: February 22, 2007
    JOURNAL FREE ACCESS
    Sleep Apnea Syndrome (SAS) is a condition characterized by sleep-disordered breathing resulting in health impairment and sleep problems. From the viewpoints of the prevention of health impairment, accidents at work and traffic accidents, active implementation of screening for SAS in workplaces is necessary. Using a portable pulse oximeter, we conducted SAS screening for workers, who applied for the screening or who were instructed to participate by occupational physicians based on their symptoms at the time of medical check-up, in order to evaluate the effectiveness of a portable pulse oximeter as a screening device in the workplace. During the 2-yr study period from April 2002 to March 2004, 380 workers underwent overnight pulse oximetry at home; data on 367 of them were considered valid and included in the analysis. We deemed screening-positive as oxygen desaturation of the peripheral artery of 4% or greater if 10 or more events were observed per hour (ODI4≥10); or oxygen desaturation of the peripheral artery of 3% or greater if 15 or more events were observed per hour (ODI3≥15). Eighty-three subjects were identified as screening-positive and 54 of them underwent polysomnography. All of them were diagnosed as having SAS with an apnea hypopnea index (AHI)≥5, of which continuous positive airway pressure (CPAP) therapy was indicated in 48 cases (88.9%) with AHI≥20. On the other hand, 11 of the 284 screening-negative subjects with mild sleep disordered breathing underwent polysomnography and all of them were diagnosed as having SAS with AHI≥5. However, CPAP therapy was indicated only for 5 with AHI≥20 of the 11. Therefore, in total, 65 subjects were diagnosed with SAS in this study and for 53 of them CPAP therapy was indicated. The simplicity of the SAS screening by pulse oximetry makes it easy to use for screening of workers, and this method was highly effective in detecting individuals with severe SAS for whom CPAP therapy was indicated.
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  • Rie Narai, Tsunehiro Oyama, Masanori Ogawa, Tetsunosuke Yamaguchi, Tsu ...
    2007 Volume 49 Issue 1 Pages 9-16
    Published: 2007
    Released on J-STAGE: February 22, 2007
    JOURNAL FREE ACCESS
    Around three million Japanese are persistently infected with HBV or HCV. Though most of them work in various industries, little is known about the actual conditions in their workplaces. To clarify the workplace conditions of workers with hepatitis, three kinds of questionnaire surveys, answered by occupational health physicians and workers with hepatitis, were carried out. The rates of workers recognized as workers with hepatitis B or C by occupational health physicians were 0.82% and 0.48% of 130,092 workers, respectively. About 30% of workers with hepatitis were engaged in "hazardous work". The percentage of workers engaged in various types of hazardous work among workers with hepatitis was nearly the same as that among all Japanese workers. About 30% of occupational health physicians witnessed exacerbation of hepatitis in the workers at their workplaces, and 22% of workers with hepatitis experienced exacerbation of hepatitis. The rate of workers with hepatitis who had experienced exacerbation was not significantly different between workers with and without hazardous work. Workers with hepatitis have strong concerns about the relationship between work and exacerbation. As causes of exacerbation, occupational health physicians cited "unknown", "drinking" and "quit treatment" while workers with hepatitis answered "work-related causes", besides "unknown" and "drinking."
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  • Emi Dote, Tomotaro Dote, Hiroyasu Shimizu, Yukari Shimbo, Michiko Fuji ...
    2007 Volume 49 Issue 1 Pages 17-24
    Published: 2007
    Released on J-STAGE: February 22, 2007
    JOURNAL FREE ACCESS
    Cadmium nitrate Cd(NO3)2 (CdN) is commonly used in Ni-Cd battery factories. The possibility of accidental exposure to CdN is great. CdN is very soluble in water compared to other Cd compounds. Therefore, acute toxicity would be expected to be quick due to rapid absorption after exposure. However, the mechanisms of CdN toxicity have not been fully elucidated. We investigated the acute lethal toxicity and harmful systemic effects of acute exposure to large doses of CdN. The lethal dose and dose-response study of the liver and kidney were determined after intravenous administration of CdN in rats. The LD50 of CdN was determined to be 5.5 mg/kg. Doses of 2.1, 4.2, 6.3 mg/kg were selected for the dose-response study. Liver injury was induced at doses greater than 4.2 mg/kg. Severe hepatic injury occurred in the 6.3 mg/kg group, which would have been caused by acute exposure to the high concentration of Cd that exceeded the critical concentration in hepatic tissue. A remarkable decrease in urine volume in the 6.3 mg/kg group indicated acute renal failure. A decrease in creatinine clearance suggested acute glomerular dysfunction at doses greater than 4.2 mg/kg. Increases in urinary N-acetyl-β-D-glucosaminidase/creatinine, β2-microglobulin and glucose in the 6.3 mg/kg group indicated proximal tubular injury. Secretion of K ion was also severely affected by proximal tubular injury and severe decreases in urine volume, and an increase in serum K ion was identified at doses greater than 4.2 mg/kg. Thus severe hyperkalemia might be associated with the cardiac-derived lethal toxicity of CdN.
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  • Donguk Park, Kuwon Chin, Hunseok Kwag, Kanwoo Youn, Sangjun Choi, Kwon ...
    2007 Volume 49 Issue 1 Pages 25-31
    Published: 2007
    Released on J-STAGE: February 22, 2007
    JOURNAL FREE ACCESS
    Exposure to metalworking fluids (MWF) mist and cross-shift decrements in peak expiratory flow (PEF) were evaluated and their relationship was analyzed using several statistical methods. The objective of this study was to assess workers, exposure to MWF mineral mist and to find the MWF mist level for predicting cross-shift decrements in PEF. A total of 158 workers handling water-soluble MWF had MWF mist exposures with an arithmetic mean (AM) of 0.4 mg/m3 (range: LOD-13.5 mg/m3), and 9.2% of workers (219) showed a cross-shift decline greater than 10% in PEF. MWF mist exposure and cross-shift decrements in PEF that were matched (n=113) were linearly significantly associated (R2=0.036, p=0.045) although the correlation was quite weak (r=0.189). We found a slight increase in cross-shift decrements in PEF with increased exposure to MWF aerosol mass concentration. The MWF mist exposure level was categorized into two or three groups by the cutoffs of either the National Institute for Occupational Safety and Health's Recommended Exposure Level (NIOSH REL: 0.5 mg/m3) or the American Conference of Governmental Industrial Hygienists Notice of Intended Change (ACGIH NIC: 0.2 mg/m3). The cross-shift decrement in PEF observed from workers exposed to ≥0.2 mg/m3 was slightly higher than that of the exposure level of ≤0.2 mg/m3 at p=0.207 while significant differences among categorized exposure groups (2 categories, <0.5 and ≥0.5 mg/m3, or 3 categories, <0.2, 0.2-0.5 and ≥0.5 mg/m3) were not detected. In order to find out whether there is a specific level that allows us to predict cross-shift decrements in PEF, several statistical models were constructed. Logistic regression showed that the MWF concentration, whether treated as a continuous variable or a categorical variable, was not significantly associated with cross-shift decrements dichotomized by a cutoff of either 10% or 15% in PEF. We couldn't find evidence of a significant PEF decrement increase with increasing exposure category. Thus, we concluded that PEF decrements measured in workers exposed to MWF mist concentrations greater than either 0.2 mg/m3 or 0.5 mg/m3 was not significantly different from those found in workers exposed to lower MWF mist concentrations. Further study is needed to establish the level of MWF mineral mist predicting non-malignant respiratory health effects.
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  • Kui-Cheng Zheng, Makoto Ariizumi
    2007 Volume 49 Issue 1 Pages 32-38
    Published: 2007
    Released on J-STAGE: February 22, 2007
    JOURNAL FREE ACCESS
    Noise has long been realized as an environmental stress causing physiological, psychological and behavioral changes in humans. The aim of the present study was to determine the effect of acute or chronic noise stress on both cellular and humoral immune responses and oxidative status. BALB/c mice were exposed to 90 dB (A) white noise 5 h per day for either 3 d or 4 wk. Hormone levels, splenic lymphocyte proliferation, lymphocyte subsets in spleen and thymus, serum antibody and oxidative status were determined. A 3-d exposure to noise stress resulted in increased hormone levels, splenic lymphoproliferation and serum IgM. On the other hand, a 4-wk exposure to noise stress caused a reduction of splenic lymphoproliferation, splenic CD4+ cells and serum IgG, but hormone levels and urinary 8-hydroxy-2'deoxyguanosine (8-OHdG) were increased. These results imply that acute exposure to noise stress may enhance immune responses, whereas chronic exposure to noise stress may suppress both cellular and humoral immune functions. The effect of noise stress on immune functions may be related to neuroendocrine modulation and oxidative imbalance as well.
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  • Yoshihiro Takashima, Narufumi Suganuma, Hirofumi Sakurazawa, Harumi It ...
    2007 Volume 49 Issue 1 Pages 39-45
    Published: 2007
    Released on J-STAGE: February 22, 2007
    JOURNAL FREE ACCESS
    Storage phosphor computed radiography (SR) and flat-panel detector (FPD) radiography are two types of digital X-ray utilizing different techniques. We compared these two techniques with conventional analogue chest radiograph (AR) among pneumoconiotic patients and healthy controls. Thirty individuals consisting of 20 silica-exposed ex-workers and 10 healthy controls without occupational exposure to any mineral dust were examined with chest X-ray by AR, SR and FPD. Three occupational physicians, including one NIOSH B reader, assessed the digital and conventional radiographs by the side-by-side method according to the ILO 2000 International Classification of Radiograph of Pneumoconioses (ILO/ICRP). No significant difference was shown between the subjective film qualities by AR and FPD. Inter-reader agreement of the profusion of small opacities on radiographs was high in the order of SR (κ=0.64), FPD (κ=0.62), and AR (κ=0.55). The profusions of small opacity for AR and FPD by the 12-point scaled profusion of ILO/ICRP did not show a statistically significant difference, but those for AR and SR showed a significant difference. The areas under the receiver operator curves (ROC) using clinical diagnosis by a pulmonologist as the reference showed no statistically significant difference among the three radiographic techniques. FPD gives image quality as good as that of AR, and it has acceptable agreement with AR in small profusion categories, which consequently assures its application to pneumoconiosis screening. SR showed less profusion than FPD and AR, which can be fixed with image modification.
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  • Masanori Ohta, Tetsuya Mizoue, Norio Mishima, Masaharu Ikeda
    2007 Volume 49 Issue 1 Pages 46-52
    Published: 2007
    Released on J-STAGE: February 22, 2007
    JOURNAL FREE ACCESS
    Although some evidence suggests that exercise may improve mental health status, information regarding the intensity and duration of exercise is incomplete. The purpose of this study was to elucidate the association between physical activities in both leisure time and commuting to work and mental health. A questionnaire survey was conducted at three municipal offices in Japan. A total of 670 men and women completed the questionnaire. Mental health status was assessed by the 28-item General Health Questionnaire (GHQ). Respondents were asked about weekly hours of leisure-time exercise for four levels of exercise, and the volume of exercise was assessed using a metabolic equivalent task index. Information about commuting to work on foot or by bicycle was also obtained. The mean GHQ scores were calculated according to physical activity levels using analysis of covariance with adjustment of potential confounders including job stress. In men, the GHQ score decreased steadily with increasing levels of leisure-time exercise, and an inverse association was evident even for mild intensity exercise. Moreover, the GHQ score decreased according to increasing duration of time on commuting to work by either walking or cycling in men, but not in women. These relations did not materially change after adjustment for potential confounding factors. In women, there was no significant association between any of the indices of physical activity. In conclusion, leisure-time exercise and walking or cycling during commuting to work may be associated with better mental health in men.
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  • Jonguk Won, Yeonsoon Ahn, Jaesuk Song, Donghee Koh, Jaehoon Roh
    2007 Volume 49 Issue 1 Pages 53-60
    Published: 2007
    Released on J-STAGE: February 22, 2007
    JOURNAL FREE ACCESS
    This study was performed to determine the differences in occupational injuries and illnesses between white-collar and blue-collar workers and to estimate the magnitude of the underreporting of these injuries and illnesses in Korea. Two datasets were used. One was a cohort established in the Gyeongin area with workers who underwent mandated health examinations, and the other was the National Health Insurance (NHI) data of claims submitted by workers employed between 1999 and 2001. Workers were classified into two groups-white-collar and blue-collar workers-according to their job types and the type of health examination they received. Injury rates were calculated for white-collar and blue-collar workers. The differences in the incidences of musculoskeletal diseases or injury and poisoning between the two groups were regarded as unreported occupational injuries or illnesses. Thereafter, work-related injury rates were estimated. With regard to medical treatment for musculoskeletal diseases or injuries and poisonings covered by the NHI, blue-collar workers had 3.47 more cases per 100 person-years than white-collar workers. This translates into a rate of between 12.57 and 18.1 injured workers per million working hours. The injury rate was 2.74 to 3.29 injured workers and the incidence rate was 3.62 to 5.44 injuries and illnesses per hundred workers. The estimated occupational injury and illness rates in this study were likely to be two to three times higher than those officially reported. However, the limitations of the study should also be considered.
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Field Study
  • Karen Belkic, Olesja Nedic
    2007 Volume 49 Issue 1 Pages 61-71
    Published: 2007
    Released on J-STAGE: February 22, 2007
    JOURNAL FREE ACCESS
    This study examined the relationship between work stressors and lifestyle-related cancer risk factors (LRCRF): smoking, obesity, sedentariness and alcohol consumption, among 112 female physicians in Novi Sad, a region of high LRCRF prevalence. The participation rate was 92.6%. Participants completed the physician-specific version of the Occupational Stress Index (OSI). Self-reported data concerning LRCRF and working conditions were cross-validated with medical records, as well as with worksite measurements and expert observations. A total of 35 (31.3%) of the physicians were current smokers and 10 (8.9%) were heavy smokers (>20 cigarettes/day); 23 (20.5%) had a body mass index (BMI) of 28 or more, and 11 (9.8%) were obese (BMI≥30). Only 27 (24.1%) regularly engaged in recreational physical activity (PA). Slightly over 5% consumed alcohol daily. Altogether 15 (13.4%) had a low lifestyle-related cancer risk profile (not a current smoker, BMI<28, regular recreational PA and no daily alcohol consumption). Total OSI and several OSI aspects, particularly threat avoidance alone or in combination, showed significant multivariate associations with LRCRF, as did individual OSI elements. The latter included long work hours, restricted problem-solving strategy, insufficient help with clinical difficulties and supervisory responsibility (obesity and/or sedentariness) and problems hampering patient care (smoking). There is an urgent need to lower the LRCRF among female physicians in this high risk region. Our findings suggest that diminishing the work stressor burden should be considered when developing intervention strategies aimed at these risk factors.
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Occupational Health/Safety in the World
  • Donald J Wilson, Ken Takahashi, Sonoko Sakuragi, Masako Yoshino, Tsuto ...
    2007 Volume 49 Issue 1 Pages 72-79
    Published: 2007
    Released on J-STAGE: February 22, 2007
    JOURNAL FREE ACCESS
    The aim of this study was to assess the relationship between the ratification status of occupational safety and health (OSH)-related ILO conventions and reported occupational fatality rates of ILO member countries, while controlling for possible confounding factors. ILO member states were divided into 4 levels of income status, based on the gross national income per capita. Seventeen conventions designated as OSH-related were examined. Reported country occupational fatality rates were compared according to the ratification status of these 17 conventions and multiple regression analyses were conducted to assess the relationship between the fatality rates, ratification status, income level and length of ILO membership. Fatality rates were inversely and significantly related to income levels. In general, non-ratifying countries had higher work-related fatality rates than ratifying countries. A statistical model for identifying predictors of fatal injury rates showed that a larger number of conventions ratified was significantly associated with lower fatality rates. The fact that non-ratifying countries generally have higher fatality rates than ratifying ones supports the notion that all countries should promote ratification of ILO conventions aimed at improving OSH conditions.
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