Journal of Occupational Health
Online ISSN : 1348-9585
Print ISSN : 1341-9145
ISSN-L : 1341-9145
Volume 44, Issue 5
Displaying 1-13 of 13 articles from this issue
Rapid Communication
  • Seigo YAMAMOTO, Tatsuya KASAI, Michiharu MATSUMOTO, Tomoshi NISHIZAWA, ...
    Article type: Rapid Communication
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 283-293
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    A bioassay study of carcinogenicity and chronic toxicity of chloroform was undertaken by inhalation exposures of groups of 50 F344 rats and 50 BDF1 mice of both sexes to chloroform for 6 h/d × 5 d/wk × 104 wk. The exposure concentration was 0 (control), 10, 30 or 90 ppm for rats and 0, 5, 30 or 90 ppm for mice. Combined incidences of renal cell adenomas and carcinomas, and of hepatocellular adenomas and carcinomas increased in the exposed male and female mice, respectively. Incidences of atypical tubule hyperplasia, cytoplasmic basophilia and nuclear enlargement in the kidneys and fatty change in the liver increased in the exposed male mice. Increased incidence of altered cell foci in the exposed female mice was causally related to the hepatocellular adenomas and carcinomas. No significantly increased incidence of the kidney or liver tumors was observed in the exposed rats of either sex. Increased incidences of nuclear enlargement and dilatation of tubular lumen were found in the kidneys of exposed rats. No-observed-adverse-effect-levels (NOAELs) for the biologically significant endpoint were determined from the dose-response relationships of the present datasets. The NOAEL for the histopathological endpoint of the kidneys resulted in 5 ppm for mice and 10 ppm for rats. An occupational exposure limit for chloroform was discussed in light of the NOAELs.
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Originals
  • Ching-Chang LEE, Mei-Ru CHEN, Tung-Sheng SHIH, Perng-Jy TSAI, Ching-Hu ...
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 294-300
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    The present study was set out to assess the exposure levels of volatile organic compounds (VOCs) for tollway station workers via direct and indirect approaches. For direct approach, personal samplings were conducted on 25, 30 and 31 booth attendants of a tollway station during the dayshift (08:00 AM-16:00 PM), nightshift (16:00 PM-24:00 AM), and late-nightshift (24:00 AM-08:00 AM), respectively. For each collected sample, five target VOCs including benzene, toluene, xylene, ethylbenzene and methyl tertiary-butyl ether (MTBE) were analyzed. Results show that at least four of the exposure profiles of the five target VOCs for the booth attendants on any given workshift were long-normally distributed. The above results suggest that the booth attendants on any given workshift can be regarded as a similar exposure group (SEG). The exposure levels for both the dayshift and the nightshift booth attendants were quite similar, but were significantly higher than those for the late-nightshift booth attendants. A similar tend was found in the vehicle flow rates. The above results indicate that the difference in VOC exposure levels for the booth attendants on the three workshifts could be due to the intrinsic difference in the vehicle flow rates. After conducting linear regression analyses, we found that the vehicle flowrates were able to explain the variation in VOC exposure levels up to 40%-52%. It is concluded that the vehicle flow rates can be used as an indirect indicator for predicting the booth attendants’ VOC exposure levels.
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  • Takero KAIDO, Yasushi HONDA, Kuniaki KITAMURA
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 301-306
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    This cohort study investigated the association between liver dysfunction and two types of impaired glucose metabolism, i.e., hyperglycemia (HG) and quasidiabetes mellitus (quasi-DM)(quasi-DM was treated as a subset of HG). Accordingly, the study consists of a quasi-DM study and an HG study. Study subjects were middle-aged male workers at printing and paper-making plants who participated in both 1993 and 1997 annual health checkups. In the quasi-DM study, the number of subjects was 1, 422. A logistic regression model revealed that live dysfunction (AST>40IU/l and/or ALT>40IU/l and/or GGT>80IU/l) and obesity (BMI>=25 kg/m2) in 1993 were associated with an increased risk of having quasi-DM in 1997 (odds ratio (OR) for liver dysfunction = 2.1, 95% confidence interval (CI): 1.1-4.1; OR for obesity = 2.0, 95%CI: 1.0-4.0). For alcohol intake, the relationship was positive for former drinkers and negative for current drinkers (for former drinkers, OR=2.7, 95%CI: 0.86-8.6, and for current drinkers, OR=0.39, 95%CI:0.19-0.81). Age and smoking status did not show a meaningful association. In the HG study, the number of subjects was 1, 254. In an analysis identical to that of the quasi-DM study, we found that liver dysfunction and obesity in 1993 was associated with an increased risk of having HG in 1997 (for liver dysfunction, OR=1.8, 95%CI: 1.2-2.7, and for obesity OR=1.6, 95%CI: 1.0-2.4). These analyses suggest that liver dysfunction can be a predictor of impaired glucose metabolism.
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  • Masayuki TATEMICHI, Tsutahiro HAMAGUCHI, Munetaka HASHIRA, Takeshi HAY ...
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 307-314
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    We undertook a prospective study to assess the long-term compliance of Japanese male workers with drug treatment for hypercholesterolemia. In workers who accepted treatment with simvastatin, an HMG-CoA reductase inhibitor, compliance was monitored every 6 months with an interview. Factors affecting compliance were identified by using the background characteristics of subjects and a self-administered questionnaire on their type of job, job style, private lifestyle and psychological status at work. Mean (SD) follow-up periods were 21.5 (10.6) months for 640 workers, and 240 noncompliant (<75% of prescription) subjects were found. Of these 240, 23 (9.6%) were restored to be finally compliant at the last follow-up (re-compliant). We assessed the time-course rate of compliant subjects and factors affecting drug compliance using Cox proportional hazard model by setting occurrence of a noncompliant attitude to an endpoint. The cumulative compliance rate at 36 months was 0.508 when excluding 23 re-compliant subjects and 0.529 when considering them as compliant. Multivariate analysis showed that age and present medical illness with hypertension (HT) in background characteristics of subjects and the habit of having breakfast daily in factors related to private-lifestyle were significantly associated with compliance. Baseline lipid profiles and work related issues were not associated with compliance. The occurrence rate of side effects did was similar in compliant and noncompliant workers. In this study, even though considering the re-compliant subjects, the rate of compliant subjects over a 3-yr period was considerably low (around 50%). The factors related to compliance were age, present illness with HT and the habit of having breakfast daily.
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  • Masaiwa INOUE, Noriaki HARADA
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 315-320
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    Whether smoking is associated with musculoskeletal disorders is still debatable. To determine the prevalence of musculoskeletal disorders among smoking and non-smoking employees doing strenuous physical work, we conducted a survey by means of a questionnaire that was distributed as a part of the annual health examination in a pulp and paper mill. The questions included smoking habit and musculoskeletal symptoms in the neck, arms, shoulders, back and low back. The analysis was performed on 905 male employees working in the manufacturing plant. For most age groups and regions, the percentage of smokers was greater among subjects with symptoms than among subjects without symptoms. Particularly among subjects in their 20s and 50s, there were significant differences in the percentage of smokers with symptoms and the percentage of smokers without symptoms (P<0.01 for both age groups). Although the percentage of ex-smokers was greater among subjects without symptoms than among subjects with symptoms, the difference was not significant except among subjects in their 50s (P=0.023). The percentages of ex-smokers in their 50s were greatest among subjects without symptoms for all 5 musculoskeletal regions. When the percentages of current smokers were analyzed according to the number of regions in which musculoskeletal symptoms were present, the number of regions tended to increase with the percentage of smokers but not significantly. Our study supports an association between habitual smoking and musculoskeletal symptoms with a proposal for an educational campaign aimed at helping individuals quit smoking.
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  • Mitsuyasu WATANABE, Kaori SHIBATA, Mitsushi OKADA, Yuichiro KUDO, Masa ...
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 321-328
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    Alveolar macrophages are thought to play a major role in the pathophysiology of lung diseases caused by exposure to various kinds of pathogens and particles. In the present study, the cytotoxic effect of potassium octatitanate whisker(PT) on macrophages was evaluated by means of magnetometry, lactate dehydrogenase (LDH) release measurement, apoptosis measurement and morphological observations. Alveolar macrophages obtained from Fischer rats (F344/N Slc) by bronchoalveolar lavage were incubated in vitro for 18 h with Fe3O4 as a magnetometric indicator, and PTs as test materials. In the control group and the group exposed to 10 μg/ml of PT, rapid attenuation of the remanent magnetic field (RMF), so called “relaxation, ” was observed immediately after cessation of the external magnetic field. In comparison, a delay of relaxation was observed in alveolar macrophages exposed to 20 and 40 μg/ml of PT. The decay constants, which are calculated from decreasing RMF for the first 2 min, in the groups exposed to 20 and 40 μg/ml of PT had significantly lower values than the control. LDH release induced by exposure to 20 and 40 μg/ml of PT increased significantly in a concentration dependent manner in PT-exposed macrophages, whereas only negligible LDH release was observed in control groups. The level of PT affecting alveolar macrophages was at the same concentration, and in a dose-dependent manner among relaxation, decay constant and LDH measurement. A DNA ladder detection method and morphological observations detected no apoptosis in PT-exposed macrophages. Electron microscopic examination revealed vacuolar changes and cell membrane damage in PT-exposed macrophages, but no significant changes in control macrophages. The results of magnetometry, LDH release, apoptosis measurement and electron microscopic observations suggest concentration dependent cytotoxicity caused by exposure of alveolar macrophages to PT.
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  • Jian-Nan WANG, Shih-Bin SU, How-Ran GUO
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 329-333
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    Many high-tech industries do some manufacturing processes in clean-rooms to ensure high quality and yield. To prevent contamination, workers need to put on special clothing and go through certain cleaning procedures before entry. Therefore, some workers may limit their water intake and try not to go the bathroom, which are both risk factors of urinary tract infection (UTI). To assess the prevalence and risk factors of UTI among the workers, we conducted a study in an industrial park. We recruited workers who came to the clinic in the park for an annual health examination between September 1 and December 31, 2000. From each participant we collected a urine sample and obtained related information through a questionnaire. All the 1, 054 qualified workers, including 416 men and 638 women, participated, and 693 (65.7%) were clean-room workers. Most clean-room workers were women (71.3%), and they tended to be younger and had lower frequencies of drinking water and going to the bathroom during the shift. A higher prevalence of UTI (6.2% vs. 2.5%, p=0.008) was observed among clean-room workers. After adjusting for age, frequency of drinking water, and working in clean-rooms, female gender was a significant risk factor (odds ratio [OR]=18.3, 95% confidence interval [CI]: 4.1 to 82.1) and going to the bathroom three times or more during a shift was a protective factor (OR=1.3, 95% CI: 0.1 to 1.0). In conclusion, UTI is prevalent among clean-room workers, and frequent voiding is recommended for prevention of the disease.
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  • Hiromi AIKOH, Chie TAGAWA, Takashi SHIBAHARA
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 334-336
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    Urinary excretion of mercury was determined in mice exposed to mercury vapor by using the incomplete cubane-type sulfur-bridged molybdenum complex [Mo3S4(Hnta)3]2-(referred to as the NTA complex). Mice exposed to metallic mercury vapor quickly excreted the mercury in their urine after being given the NTA complex solution. The cumulative amount of mercury in the urine of these mice was 1.3 times higher than that in mice that had received L-cysteine and 1.8 times higher than that in mice that had received water. The study revealed that the NTA complex is capable of promoting extra-corporeal excretion of mercury that had been bodily absorbed by mice.
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  • Ali NASERMOADDELI, Michikazu SEKINE, Shimako HAMANISHI, Sadanobu KAGAM ...
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 337-342
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    The combination of poor sleep quality and high job strain may provoke poor health status. Meanwhile, a sense of coherence (SOC), composed of comprehensibility, manageability and meaningfulness has been associated with adoptive measures in responding to life stress. In this study we investigated the impact of job strain on the sleep quality in civil servants and the extent to which SOC affects their sleep quality. In this cross-sectional study we evaluated 1682 civil servants working in departments related to the municipality of T city in Toyama prefecture, Japan, in the spring of 2001. Using the validated Japanese versions of Pittsburgh sleep quality index (PSQI-J), SOC-13 and a self-reported questionnaire providing information on psychosocial stress in the workplace, we conducted logistic regression analysis to assess the impact of low and high SOC (differentiating by the median score) on sleep quality in different levels of job strain. Using a cut-off point of 5.5 in the PSQI-J global score, high job strain subjects were less likely to have good sleep quality (Odds ratio=0.62; 95% confidence interval: 0.44-0.86) compared with those with lower levels of strain at the workplace after adjusting for potential confounders. Compared with high job strain/low SOC subjects, high job strain/high SOC civil servants were likely to have better sleep quality (Odds ratio=2.12; 95%Cl: 1.08-4.19) after adjusting for age, sex, employment category, level of education and negative affectivity. Increasing psychological stress at the workplace may decrease sleep quality in Japanese civil servants, but a high sense of coherence may attenuate the adverse impact of job strain on sleep quality.
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  • Kazuhito HATANAKA, AKira FUJINAMI, Yoshihiro NISHIMOTO, Nobuhiko ITO, ...
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 343-347
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    Objective—Premature ventricular contractions (PVCs) were observed among patients with heart diseases. It has been suggested that the sporadic left bundle branch block (LBBB) pattern of PVCs observed in healthy subjects has no relevance to heart diseases and the presence of this type of PVC was not associated with a poor prognosis. The aim of this study is to present and evaluate the relationship between PVC patterns on routine electrocardiography (ECG) and heart diseases. Methods: The subjects examined were 201 employees from one company (male 192, female 9) with PVCs (Lown grading classification 0 or 1). The patterns of PVCs were classified into the following four categories regarding the bundle branch block pattern and electrical axis deviation: 1) the LBBB pattern without axis deviation (135 subjects), 2) the LBBB pattern with left axis deviation (29 subjects), 3) the right bundle branch block (RBBB) pattern without axis deviation (22 subjects) and 4) the RBBB pattern with left axis deviation (15 subjects). Results—The presence of subjective symptoms was not significant in each category. Prevalence of heart disease was 1) 14 (10.4%), 2) 10 (34.5%), 3) 9 (40.9%) and 4) 7 (46.7%). The subjects with the LBBB pattern without axis deviation had a lower incidence of having heart disease than subjects with other PVC patterns (p<0.05). In addition, similar findings applied to the observations in asymptomatic subjects. Conclusion—It is suggested that the population without heart disease primarily has the PVCs of the LBBB pattern without axis deviation and the analysis of the PVC patterns (bundle branch block pattern) and of electrical axis deviation in routine ECG at a routine health examination is useful for diagnosing heart disease.
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  • Takashi SHIMIZU, Masanori HIRO, Norio MISHIMA, Shoji NAGATA
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 348-354
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    The present study investigated job stress and the factors influencing job stress among Japanese full-time occupational physicians(OPs). In 2000 we mailed self-administrated questionnaires to 716 full-time OPs who were members of “Sanyu-kai”, an organization of Japanese full-time occupational physicians in enterprises. The questionnaires included gender, marital status, age, main type of company work, the number of full-time OPs, the number of employees served, duration of work, tenure in the present company, and job stress questions. The job stress questions consisted of 15 items which were decided after discussion among 10 experienced full-time OPs. Three hundred and thirty-three (47%) of the OPs returned sufficiently complete questionnaires for analysis. Factor analysis of the job stress questions extracted three components; low understanding of occupational health services, conflicts between OPs and their partners, and discrepancies between their routine work and occupational health services. Multiple logistic regression was performed to estimate the odds ratio (ORs) for high job stress associated with age, gender, marital status, main type of work, duration of work, tenure and the number of employees. Males had less stress than females (OR=0.37, 95%CI=0.19-0.70). The 20-39-yr-old OPs had more stress than over 59-yr-old OPs (OR=2.8, 95%CI=1.5-5.6). Compared with those serving over 5, 000 employees, the OPs serving 2, 500 employees or fewer had less stress (ORs=0.43-0.52, ps<0.05). Our results indicated that job stress among Japanese full-time OPs was influenced by gender, age and the number of employees served.
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  • How-Ran GUO
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 355-359
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    Occupational and environmental regulatory standards are usually determined on the basis of data from high-dose exposures, either in humans or animals. Risk assessment models are applied to identify the level below which the risks are considered as acceptable. Even when the basis is human data, the validity of extrapolation is often questionable because the number of cases actually observed in the low-dose region is usually small, if any. Validation of the risk assessment model by using data on populations with low-dose exposures is desirable, but the lack of study power is the major concern in most cases. A meta-analysis combining data from more than one study may solve the problem, especially when a model overestimates risks associated with low-dose exposures. A maximum contaminant level (MCL) of arsenic in drinking water at 0.05 mg/l published by the US Environmental Protection Agency (EPA) was used as an example to demonstrate such a scenario. Because this MCL was derived by using data from a study on skin cancer in Taiwan, a validation was conducted by using data on Taiwanese with low-dose exposures. In comparison with the number of cases observed in four studies, the model was more likely to be invalid than to be valid at exposure levels below 0.17 ppm and overestimated the number of cases (11.08 vs. 5). Whereas the EPA has published a new MCL recently on the basis of new risk assessments on urinary bladder and lung cancers, re-visiting the validity of the old standard still provides insights for validating regulatory standards in the future.
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  • Kayoko INOUE, Iwao HIROSAWA, Miki YATSUDUKA, Takeo YOSHINAGA, Akio KOI ...
    Article type: Original
    Subject area: Others
    2002 Volume 44 Issue 5 Pages 360-372
    Published: 2002
    Released on J-STAGE: March 28, 2003
    JOURNAL FREE ACCESS
    Adverse events in hospitals are a world-wide concern. To develop a tool for quantitative risk assessment of medical error, human reliability analysis was applied to incident reports from a prospective cohort study in a hospital. 374 nurses in a tertiary-care hospital of 670 beds joined this study. Numbers of tasks, classified into 170 items, were actually measured by nurses during three weekdays and one weekend. The total number of tasks per year was found to be about 13.2 million. 1, 030 incidents were reported over a year. The gross failure rate for tasks was estimated to be −10-4. The relative risk for failure rates in midnight and night shifts was 2-4 times greater than in dayshifts. When the failure rate for a patient category of ages 15 and 64 yr old was taken as a standard, the relative risk of failure was about 200 times greater in a patient category of problematic behavior and 90 times greater in patient categories of clouding of consciousness and postsurgical conditions. Failure rates for individual tasks were in the range of 10-5 to 10-3: the tasks with the highest failure rate were prevention of problematic behavior (2.32×10-3), safeguards against falls (1.47×10-3), intramuscular injection (1.30×10-3) and subcutaneous injection of insulin (9.82×10-4). The present study revealed two potential risks: occasional tasks with high failure rates and patient categories with small numbers of patients with high failure rates. The present protocol enabled us to conduct quantitative risk assessment on occupational health for medical workers.
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