Job Stress and Mental Health among Permanent Night Workers: Yoshihisa FUJINO, et al. Department of Clinical Epidemiology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health—Shift work, including rotating shift night work, and permanent night work, causes mental health problems. In addition to the shift work system, job stress and individual background factors also relate to the mental health of workers, but details of job stress and mental health problems among permanent night workers are still unclear. The purpose of this study is to examine the amount of job stress and the mental health problems among permanent night workers, and also to examine what factors should determine the mental health condition of the permanent night worker. The study group consisted of 435 garbage workers, and 384 workers completed the questionnaire, which included the NIOSH generic job stress questionnaire and 30 items of the General Health Questionnaire (GHQ). Workers with a GHQ score of 7 or more were defined as having psychiatric disturbance. Multiple logistic regression was performed to estimate the odds ratios (ORs) for psychiatric disturbance, including age, type of work, working year, marital status, and some scales of the NIOSH generic job stress questionnaire. The married workers were less likely to have mental health problems than single workers (OR=0.49, 95% CI=0.29-0.85). The mental health of the workers with lower job control was better than the workers with higher job control (OR=0.46, 95% CI=0.26-0.79). The workers with a higher workload were more likely to have mental health problems (OR=2.86, 95% CI=1.76-4.67). This study showed that person with a high workload, high job control, and who were single had increased ORs for psychiatric disturbance among permanent night workers. (J Occup Health 2001; 43: 301-306)

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Trans-Cranial Doppler and Peripheral Sensory Threshold Tests for Carbon Disulfide Poisoning: Eunil LEE, et al. Department of Preventive Medicine, School of Medicine, Korea University—Trans-cranial doppler (TCD) and sensory threshold (vibration, pain and discrimination) tests, which are safe and inexpensive techniques, were applied to detect cerebral vasoreactivity or neuropathic changes between carbon disulfide (CS₂) poisoning cases and two control groups respectively. The cases were 31 male CS₂ poisoning workers, and the first control group for the TCD test consisted of eight healthy men, and the second group for the threshold test were 21 healthy male workers. In the TCD test, the blood flow velocity in both middle cerebral arteries and the CO₂ content of expired air were measured to evaluate CO₂ reactivity. The vibration and pain perception threshold were measured on both the 2nd and 5th fingers. The CS₂ poisoning cases showed higher rates of abnormal CO₂ reactivity above the cut-off value than healthy controls (80.0-81.8% vs 0%). Among the threshold tests, the proportions of abnormal pain threshold of both the 2nd and 5th fingers were higher in poisoning cases than in the controls (77.8%-88.9% vs 11.1-33.3%) among over 45 yr old subjects. CO₂ reactivity and pain threshold test showed the possibility to detect changes in cerebral vessels and the sensory threshold in CS₂ exposure cases, but there should be further study to apply these tests to workers exposed to CS₂ before the development of CS₂ poisoning, with large number of control subjects. (J Occup Health 2001; 43: 307-313)

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Four—Week Inhalation Toxicity Study of 2, 2—Dichloro—1, 1, 1—trifluoroethane (HCFC-123) in Guinea Pigs: Isamu KABE, et al. Department of Preventive Medicine and Public Health, School of Medicine, Keio University—Groups of eight male Hartley guinea pigs were exposed to 30, 100 or 300 ppm 2, 2—dichloro—1, 1, 1—trifluoroethane (HCFC—123) by inhalation for 6 hours a day for 4 wk. All the animals were sacrificed 48 h postexposure. Guinea pigs exposed to 300 ppm HCFC—123 had significantly lower body weight and the weight gain than controls, but there was no significant difference and no tendency in absolute and relative organ weight. ICDH, ALT and AST, which were the most sensitive indicators of halothane-induced liver injury, did not differ significantly between exposed groups and controls. In the 100 ppm group, a few vacuolar fatty changes in the portal area (zone I) were identified. In the 300 ppm group, severe fatty degeneration was observed in the portal and intermediate areas, partly centrilobule, and the incidence increased significantly compared to the controls. On the other hand, there was no histopathological change in the control or 30 ppm groups. No increase in any of the liver peroxisomal enzymes (AOX, PT, catalase) was seen in male guinea pigs exposed to HCFC—123. The activity of hepatic ALDH was significantly decreased in the 300 ppm exposed group, suggesting that HCFC—123 or its metabolite inhibited ALDH activity. In conclusion, inhalation exposure to 100 ppm or more of HCFC—123 for 4 wk produced nonfatal liver change in guinea pigs, namely hepatic fatty changes predominantly in the portal area (zone I) without any increase in AST, ALT or ICDH. The o—observed—adverse—effect level (NOAEL) of HCFC—1 23 for four wk in guinea pigs may be 30 ppm. Peroxisome proliferation, which may result in hepatocellular tumor induction, was not observed in guinea pigs exposed to HCFC—123. (J Occup Health 2001; 43: 314-320)

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Relationships between Lifestyle—Related Factors and Immune Parameters in Middle-Aged Male Workers: Yumiko NAKANO et al. Division of Industrial Health, Osaka Prefectural Institute of Public Health—Recent studies have demonstrated that unhealthy lifestyles and stress act as risk factors for various cardiovascular diseases, cerebrovascular disorders and cancer. The present study was carried out to investigate the effect of individual lifestyle and comprehensive lifestyle practices on T cell function in peripheral blood lymphocytes in 291 middle—aged male workers belonged to 4 occupational groups: selfemployed men (I), employees of a television station (II), local civil servants (III) and workers in a manufacturing factory (IV). The proliferative responsiveness of the lymphocytes to phytohemagglutinin (PHA) was measured by the incorporation of radiolabeled thymidine by stimulated lymphocytes in vitro. Interferon—γ(IFN—γ, T helper type 1 cytokine) and interleukin-4 (IL—4; T helper type 2 cytokine) production from the stimulated lymphocytes were measured by quantitative sandwich enzyme immunoassay. Interviews by means of questionnaires including 19 items related to lifestyles, work stress, life event and health condition were performed. Subjects were classified into groups reporting healthy and unhealthy lifestyles according to their responses to the individual questionnaire. Then, the relationships between these lifestyle practices and the immune parameters were analyzed at the level of the occupational groups and the pooled subjects. The average number of unhealthy practices differed significantly among occupational groups, i.e., higher in the order of I, II, III and IV. Significantly negative correlations were observed between the number of unhealthy lifestyle practices and the PHA responses both at the level of the occupational groups and the pooled subjects. In contrast, there was no significant difference in IFN—γ production among occupational groups, though the group I showed a somewhat low tendency. The levels of IL—4 in group I were noticeably higher than that in the other groups. It may be possible that severe suppression of cell—mediated immunity changes the balance of T cell subsets from T helper type 1 to T helper type 2. For each lifestyle practice, subjects reporting “healthy” practices on 7 items showed significantly greater proliferative response to PHA than those reporting unhealthy practices. Subjects reporting “healthy” practices on two items showed significantly lower levels of IL-4 compared with those reporting unhealthy practices. A 1.5—yr follow up study performed in the subjects with low PHA responses showed that the reduction of unhealthy lifestyle practices significantly improved the PHA responses. Consequently, the present study suggests that the individual unhealthy lifestyle practices may act on the immune system cumulatively, and the measurement of PHA response may be used to evaluate the lifestyle practices of middle—aged male workers at both the individual and the occupational group level. (J Occup Health 2001; 43: 321-330)

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Perfluoroisobutylene-Induced Acute Lung Injury and Mortality are Heralded by Neutrophil Sequestration and Accumulation: Hemei WANG, et al. Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences—Perfluoroisobutylene (PFIB) is a highly toxic and potentially life—threatening pneumoedematogenic agent that is usually encountered in case of fire or industrial accidents. The mechanisms by which the toxicity of PFIB are mediated remain unclear. To investigate the role of neutrophil⁄ polymorphonuclear leukocytes (PMN) in the pathogenesis of PFIB-induced acute lung injury (ALI), mice and rats were exposed to a sublethal concentration of PFIB (130 mg/m3 and 140 mg/m3, respectively) for 5 min in a flow-past whole—body chamber. The general pattern for the time-course of the increase in lung PMN infiltration as measured by lung myeloperoxidase (MPO) assay was shown to be rather similar to that of the lung injury indexed by both the total protein increase in the bronchoalveolar lavage fluid (BALF) and lung wet—to—dry weight ratio, except for the earlier start and the maximal time-point of the increase in lung PMN infiltration. When neutropenia was obtained by cyclophosphamide pretreatment, death of the mice induced by an over—LCt50 dose of PFIB (at 190 mg⁄m3 for 5min) dropped dramatically, and this was very well supported by observations in the BALF total protein analysis, histopathological as well as ultrastructural studies. These results confirmed that PFIB inhalation—induced ALI and mortality are heralded by the influx of PMNs into the lung. (J Occup Health 2001; 43: 331-338)

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Reduction of Worker Exposure to Solvents by means of an Occupational Health Program: An Experience at a Synthetic Leather Factory in Taiwan: Hsien—Wen Kuo, et al. Institute of Environmental Health, China Medical College—Objective-To assess the effects of an occupational health program which was to reduce synthetic leather workers' exposure to solvents (N, N-dimethylformamide (DMF), epichlorohydrin (ECH) and toluene). Methods—Worker exposure to these airborne solvents was measured in 1999 and compared with results obtained in 1997. Due to high solvent levels in the workplace, an occupational health program was implemented in 1997 to reduce worker exposure to solvents. Biological monitoring was conducted by measuring workers' urinary DMF, NMF (N—methylformamide) and formamide concentrations, and the factors influencing these indicators were investigated. NMF levels obtained in 1997 were compared with levels in 1999. Results-Airborne DMF, ECH and toluene concentrations were significantly reduced in all three workstations in the 1999 study (compared to the 1997 study). In 1997, the urinary NMF concentration was 3.31 mg/g cre. compared to 2.13 mg⁄g cre. in 1999, which represented a 35.6% decrease. Urinary DMF and formamide concentrations were 0.42 and 1.24 mg⁄g cre., respectively, in 1999. There was a positive correlation between urinary NMF concentration and environmental DMF (r=0.49 for area sampling, r=0.55 for personal sampling). For biological monitoring, the urinary NMF concentration was significantly correlated with formamide (r=0.79) and parent DMF (r=0.33). Multiple regressions showed that the factors affecting the concentration of the biological indicators (NMF, DMF and formamide) in urine were: airborne DMF concentration, duration of worker employment and alcohol consumption. Conclusion-The occupational health program implemented in 1997 was effective in quickly reducing airborne solvents, but urinary NMF levels were not as responsive. (J Occup Health 2001; 43: 339-345)

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Protective Effect of Clonidine against Toxicity of Organophosphorus Pesticides: Zhijun ZHOU, et al. Department of Occupational Health and Toxicology, School of Public Health, Fudan University—Aim: The purpose of this study was to check whether clonidine, a centrally active alpha—2 adrenergic agonist, could serve as an antagonist against the acute toxicity of generally used organophosphorus pesticides (OP) in laboratory animals. Methods: The tests of three factors, the dose level of pesticide, and the administration schedules for atropine and clonidine, were arranged for crosschecking according to three level orthogonal layouts. The latency of onset of apparent body tremor, loss of righting reflex and survival time was timed. Results: The survival time was longest in the treatments with 5 mg⁄kg atropine, 20 min pre OP injection or with 1 mg⁄ kg clonidine, 10 min pre—OP injection. The latency of onset of apparent body tremor and the loss of righting reflex were prolonged when clonidine or atropine was given before OP administration. Conclusion: These results indicated that the use of clonidine in the clinical treatment of intoxication by means of organophosphates is reasonable and acceptable. It is a recommendation of a new use of an old drug. Used cautiously, beneficial effects of clonidine could be expected, either separately or combined with atropine, in the treatment of organophosphate intoxication. (J Occup Health 2001; 43: 346-350)

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Association of Tooth Loss with Psychosocial Factors in Male Japanese Employees: Naoji HAYASHI, et al. Department of Preventive Dentistry, Graduate School of Dentistry, Osaka University—It would seem that good psychosocial conditions would have a positive effect on oral health, but few data exist regarding the association of psychosocial factors with tooth loss. The association between psychosocial factors and tooth loss was studied in male industrial workers in Japan. In an annual health checkup, tooth loss status was assessed by oral examination in 252 workers (age 20-59 yr). Information pertaining to psychosocial factors, lifestyle and oral health behavior was also obtained through a self-administered questionnaire. The mean tooth loss per worker showed a significant increasing trend with age. Mean tooth loss was 0.32 in the 20-29-yr-old group, 0.82 in the 30-39-yr-old group, 1.28 in the 40-49-yr-old group and 2.91 in the 50-59-yr-old group. Bivariate analyses revealed that age (P<0.01) and alexithymia (P<0.05) were significantly associated with tooth loss. In contrast, work stress, depression, type A behavior, job and life-satisfaction were not significantly associated with tooth loss. In multivariate analyses, the associations of age (P<0.02) and alexithymia (P<0.05) remained statistically significant after adjustment for oral health behavior and lifestyle variables. We suggest that an alexithymic personality may affect tooth loss status in male employees. (J Occup Health 2001; 43: 351-355)

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Vasomotor and Other Menopausal Symptoms Influenced by Menopausal Stage and Psychosocial Factors in Japanese Middle-Aged Women: Kuninori SHIWAKU, et al. Department of Environmental Medicine, Shimane Medical University—The relationship among menopausal symptoms, the menopausal stage and psychosocial factors in climacteric of Japanese women was investigated. Information on menopausal symptoms, the menstrual cycle and psychosocial factors were collected by means of a self-reported questionnaire in six rural communities. A general population sample of 2, 886 women (recovery rate of 75%) aged 40 to 69 yr completed a report on seventeen self-reported health symptoms over the preceding 12 months. The most bothersome complaints were aching/painful joints, weakness and headache that were reported by approximately half the population aged 40 to 69 yr, but less than 4% of the women were affected severely. One-third of the women were bothered by night sweats, cold hands and feet, nervousness and anxiety. Approximately one in five of the women complained of hot flushes, numbness, early waking, and sleeplessness. Four factors emerged from a factor analysis: general somatic symptoms, psychological symptoms, vasomotor symptoms and aging symptoms. Hot flushes, night sweats, numbness, early waking and sleeplessness were significantly higher in the perimenopausal and postmenopausal periods than in the premenopausal period of women aged 45 to 54 yr. The menopausal stages were significantly related to the vasomotor symptoms, but had little relationship to the other menopausal symptoms, in a logistic regression model. Japanese women characteristically have a lower incidence of vasomotor and other menopausal symptoms, and a lower utilization of medical treatment for menopausal symptoms. Vasomotor symptoms were clearly associated with menopause, but other menopausal symptoms in Japanese middle-aged women related to self-rated health, social support and occupation. (J Occup Health 2001; 43: 356-364)

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Asbestos-Related Pleural Abnormalities Detected by Chest X-Ray: Fair Agreement with Detection by Computed Tomography: Narufumi SUGANUMA, et al. Department of Environmental Health, Fukui Medical University School of Medicine, Fukui—The International Labour Office (ILO) 1980 International Classification of Radiograph for Pneumoconioses (ILO 1980) is used widely round the world for the evaluation of dust-exposed workers, whereas computed tomography (CT) has been introduced for more accurate diagnosis of pneumoconioses. This study is aimed to assess whether the chest X-ray can detect pleural abnormalities as accurately as CT in patients with asbestos-related lung diseases in the early stages. Eighty subjects with positive finding in 10 cm x 10 cm CXR were selected from 1178 ex-workers with asbestos exposure for the study. They underwent CXR and CT to be assessed by two ILO 1980 experts for CXR and a chest physician and a radiologist for CT films according to ILO 1980 and the CT criteria, respectively, which we developed. The CT and CXR readings were obtained independently. Scores of the extent of pleural abnormalities agreed on by two readers were compared in CT and CXR. Sensitivity and specificity of CXR for detecting pleural abnormalities by CT result as a gold standard were also calculated. Among the 80 subjects, there were 66 patients (83%) who had pleural abnormalities detected by CXR. Of these 66 persons, CT confirmed 61 subjects to have pleural plaque. The reading results of CXR and CT showed fair agreement with Cohen's weighted kappa of 0.53. Sensitivity and specificity of CXR and CT were 0.94 and 0.73, respectively. Fair agreement was seen between CXR and CT in detecting pleural plaque in terms of extent in dust-exposed workers. Such a standardised system as ILO 1980, CXR is still useful for the screening for pleural abnormalities in dust-exposed individuals. (J Occup Health 2001; 43: 365-370)

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Common Health-Care Units in Industrial Parks in Taiwan: Shih-Bin Su, et al. Graduate Institute of Environmental and Occupational Health, Medical College, National Cheng Kung University—In Taiwan, according to the Worker'' Health Protection Regulation (the Regulation), factories with more than 300 employees in total or more than 100 employees engaged in specific hazardous tasks are required to establish on-site health-care units. In addition to general primary care, these units should serve eight specific functions, including health education and promotion, diagnosis and treatment of occupational diseases, vaccination, job placement, health examination, study of occupational health and maintenance of records of occupational diseases and injuries, prevention of occupational diseases and improvement of work environments, and family planning. Factories in the same industrial park are allowed to establish a common health-care unit instead of individual health-care units in the factories. We conducted a nationwide survey of the industrial parks and, through site visits, collected data on the pattern of organization, manpower, and services of their common health-care units with a standard questionnaire. We also evaluated their functions as set forth by the Regulation. As a result, we found only 10 of the 65 (15.4%) industrial parks had common health-care units and obtained data on 8. The variations in the pattern of organization, manpower, and services were quite large, but most of the units did not carry out all the eight essential functions. Because the establishment of a common health-care unit can save cost, it is planned by many industrial parks under construction. The results of our survey showed that these units may not function well, which calls for more thoughtful planning and proper law enforcement. (J Occup Health 2001; 43: 382-387)

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