Objectives: To review empirical research on adverse health and pregnancy outcomes associated with physiotherapists' occupational exposure to radiofrequency electromagnetic fields (RF EMFs) from shortwave (SWD) and microwave (MWD) diathermy devices. Methods: A systematic review of peer reviewed literature published from 1990 to 2010 in the English language searched in eight online bibliographic databases: CINAHL, EBSCOhost, ISI Web of Knowledge, Medline, OSH UPDATE, PubMed Central, ScienceDirect, and Scopus. Results: Findings suggest that physiotherapists' occupational exposure to SWD was statistically significantly associated with delayed time to pregnancy (>6 months), still birth, altered gender ratio (low ratio of boys to girls), congenital malformations and low birth weight (<2,500 g) among physiotherapists' offspring. Physiotherapists' exposure to MWD was also found to be statistically significantly associated with spontaneous abortion. However, causal mechanisms for these statistical associations are unknown. The present systematic review has found these adverse reproductive outcomes and health effects associations with RF EMFs from therapeutic diathermy devices to be inconsistent. Conclusions: A number of studies did not find statistically significant results to replicate associations with such adverse outcomes, and therefore further research, preferably prospective studies of cohorts of physiotherapists, is warranted.(J Occup Health 2014; 56: 323-331)
Objective: This study aimed to identify chemicals used by printing workers with cholangiocarcinoma, as well as the levels of exposure to the chemicals. Methods: Information necessary to identify chemicals used by printing workers with cholangiocarcinoma and to estimate chemical exposure concentrations was obtained from the Ministry of Health, Labour and Welfare, Japan. Working environment concentrations of the chemicals in the printing rooms were estimated using a well-mixed model, and exposure concentrations during the ink removal operation were estimated using a near-field and far-field model. Shift time- weighted averages (TWA) of exposure concentrations were also calculated. Results: Two workers from each of three small printing plants examined suffered from cholangiocarcinoma, and all six of these workers had been exposed to 1,2-dichloropropane (1,2-DCP) for 10–16 years. The estimated working environment concentrations of 1,2-DCP in the printing rooms were 17–180 ppm and estimated exposure concentrations during the ink removal operation were 150–620 ppm. Shift TWA values were estimated to be 62–240 ppm. Four of the six workers had also been exposed to dichloromethane (DCM) at estimated working environment concentrations of 0–98 ppm and estimated exposure concentrations during the ink removal operation of 0–560 ppm. Shift TWA values were estimated to be 0–180 ppm. Other chlorinated organic solvents (1,1,1-trichloroethane, 1,1-dichloro-1-fluoroethane) and petroleum solvents (gasoline, naphtha, mineral spirit, mineral oil, kerosene) were also used in the ink removal operation. Conclusions: All six printing workers with cholangiocarcinoma were exposed to very high levels of 1,2-DCP for a long term.(J Occup Health 2014; 56: 332-338)
Objectives: The aim of this study was to examine whether the association between employment contract and self-rated health differs by household structure in a representative sample of employees in Japan. Methods: The participants were 81,441 male and 64,471 female employees aged 18–59 years who had participated in the 2010 Comprehensive Survey of Living Conditions. We assessed the interactive effect of employment contract (permanent or precarious) and household structure (couple only, couple with children, single parent, single person, or other multi-person) on fair/poor health, adjusting for covariates by using logistic regression. We then calculated the relative poverty rate by employment contract and household structure. Results: The interaction effect was significant for women (p<0.001) but not for men (p=0.413). A higher percentage of female precarious workers who lived in single-parent households (20.2%) reported fair/poor health compared with those in other types of households (10.4–13.2%), although the prevalence of fair/poor health did not differ substantially by household structure among female permanent workers. The relative poverty rates of female precarious workers who lived in single-parent households were higher compared with those of other female workers. Conclusions: Our results suggest that female precarious workers are not a homogeneous group and that those living in single-parent households suffer from poor health due to low income and insufficient coverage by insurance firms and family-based safety nets.(J Occup Health 2014; 56: 339-346)
Objectives: The purpose of this study was to develop a simple and cost-effective method for the determination of urinary 4,4′-methylenebis (2-chloroaniline) (MBOCA) by gas chromatography-electron capture detection (GC-ECD) for biological monitoring of occupational exposure to MBOCA. Methods: MBOCA was prepared by liquid-liquid extraction after alkaline hydrolysis, derivatized with N-methyl-bis (trifluoroacetamide) and then analyzed using GC-ECD. The proposed method was validated in accordance with the US Food and Drug Administration guidance. Results: The calibration curve showed linearity in the range 1–100 µg/l, with a correlation coefficient of >0.999. The limits of detection and quantification were 0.3 µg/l and 1 µg/l, respectively. The recovery was 94–99%. Intraday accuracy, expressed as the deviation from the nominal value, was 90.5–100.3%, and intraday precision, expressed as the relative standard deviation, was 0.3–2.4%. Interday accuracy and precision were 87.8–100.2% and 0.3–4.1%, respectively. Conclusions: The proposed method is a simple and cost-effective method suitable for routine analyses and could be useful for biological monitoring of occupational exposure to MBOCA.(J Occup Health 2014; 56: 347-350)
Objective: Workplace aerosol sampling is challenged by its influencing factors and methodological limitations. Some factors, including blank setting, electrostatic effect, sample mass gain, and limit of detection (LOD), were studied to characterize them further and thereby to improve the sampling method. Methods: Through a field sampling in two shipyards and by an analysis of a large amount of dust data from different industries, the influencing factors were comparatively studied with emphasis on their effect on the final result. Results: After calibration with field blanks, the concentrations of most sample types in the shipyards decreased significantly, varying by as much as −24.3% of the final measurements. After laboratory blank calibration, dust concentrations increased or decreased without a definite change trend. With a variation of −1.8%, only the measurements of Chinese “total dust” sampled with polypropylene filters were significantly influenced by the electrostatic effect. The LOD coincidence rate was only 17.3% for American respirable dust in different industries and 12.2% for respirable particles collected by normal flow rate samplers (FSP2) in the shipyards. The latter increased to 73.9% when high flow samplers (FSP10) were used. Conclusions: It was suggested that field blank calibration was the predominant influencing factor in comparison with electrostatic effect and laboratory blank adjustment. The LOD coincidence rate was too low for reliable sampling, and this might be improved by use of high flow samplers.(J Occup Health 2014; 56: 351-358)
Objectives: Although workers with poor sleep quality are reported to have problems with work performance, few studies have assessed the association between dietary factors and sleep quality using validated indexes. Here, we examined this association using information acquired from validated questionnaires. Methods: A total of 3,129 female workers aged 34 to 65 years were analyzed. Dietary intake was assessed using a self-administered diet history questionnaire (DHQ), and subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). The relationship between the intake of several food groups and nutrients and sleep quality was examined using multivariable logistic regression models. The effect of eating habits on sleep quality was also examined. Results: Poor sleep quality was associated with low intake of vegetables (p for trend 0.002) and fish (p for trend 0.04) and high intake of confectionary (p for trend 0.004) and noodles (p for trend 0.03) after adjustment for potential confounding factors (age, body mass index, physical activity, depression score, employment status, alcohol intake and smoking status). Poor sleep quality was also significantly and positively associated with consumption of energy drinks and sugar-sweetened beverages, skipping breakfast, and eating irregularly. In addition, poor sleep quality was significantly associated with high carbohydrate intake (p for trend 0.03). Conclusions: A low intake of vegetables and fish, high intake of confectionary and noodles and unhealthy eating habits were independently associated with poor sleep quality. Poor sleep quality was also associated with high carbohydrate intake in free-living Japanese middle-aged female workers.(J Occup Health 2014; 56: 359-368)
Background: A previous explorative record-linkage study suggested a putative role of employment in electrical manufacturing in increasing female breast cancer risk in the Province of Milan (Italy). We deepened the understanding of this possible association in a single large electrical manufacturing plant located in Lombardy in the Province of Milan. Methods: We carried out a nested case-control study within a cohort of women employed in a large electrical manufacturing plant. All incident cases during 2002 to 2009 of female breast cancer in individuals who worked at least a 1 year in the factory and resided in Lombardy, Italy, were selected. Controls were randomly sampled from all women who worked in the same plant and resided in Lombardy as of December 31, 2005. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated using multiple logistic regression models, taking into consideration only female workers as ever/never exposed to physical/chemical agents and their longest occupational period. ORs were adjusted for several potential confounders, namely, other known risk factors. Results: The ORs for female breast cancer were significantly increased for exposure to chlorinated solvents (OR 1.65, 95% CI 1.04–2.62), and there was a twofold increase (OR 2.10, 95% CI 1.21–3.66) among women exposed for at least 10 years. We found no other significantly increased OR by exposure or job title. Conclusions: Our results suggest an increased risk of breast cancer after exposure to chlorinated solvents among women employed in the electrical manufacturing industry.(J Occup Health 2014; 56: 369-378)
Objectives: The aim of this study was estimation of DNA strand breaks in leukocytes of peripheral blood of staff in a nuclear medicine department. Methods: The exposed group consisted of 46 volunteers and the control group consisted of 40 volunteers. Samples consisting of 1 ml whole blood were collected by venepuncture. DNA damage in leukocytes was detected by alkaline comet assay. Results: There was no correlation between the effective dose measured by individual dosimeters and DNA damage and no differences between sexes. The mean level of damage to DNA in people exposed to ionizing radiation was significantly elevated compared with control individuals. The highest value for mean comet tail moment was noted in leukocytes of PET/CT and scintigraphy technicians (1.28 vs. 0.30 for control, p=0.013). The levels of DNA damage in leukocytes of workers in category B (effective dose may exceed 1 mSv/year) were significantly enhanced. The DNA migration of leukocytes in exposed smokers and nonsmokers was similar. In the control group the damage to DNA of leukocytes in smokers was markedly but not significantly higher compared with nonsmokers. Conclusions: Occupational exposure to ionizing radiation leads to enhanced levels of reversible DNA damage in leukocytes of nuclear medicine employees. The level of DNA damage depends on the kind of work. Cigarette smoking is related to the increase in DNA damage in unexposed individuals but not in nuclear medicine workers. Radiation seems to be a stronger inducer of DNA damage than smoking. Although most of the DNA damage detected by comet assay is repaired, further improvement of radiation safety should be taken under consideration.(J Occup Health 2014; 56: 379-386)
Objective: The aim of this study was to examine the usefulness of a portable Internet-enabled ECG recording system (iECG) in monitoring the heart health of Japanese individuals working abroad. Methods: This study included 24 male Japanese individuals working abroad, who had been found to have risks of cardiovascular diseases (CVDs) at periodic health checkups. The subjects were instructed to send ECG recordings obtained by the iECG via a personal computer from their countries of residence. Interpretations of the ECG results were shared with the participant and the participant's occupational physician via e-mail. Further, a questionnaire survey was conducted among the subjects to determine the usefulness of the iECG. Results: Only 21 subjects (53.7 ± 5.2 years) could send their ECG recordings from their countries of residence. During the monitoring period (average, 0.7 ± 0.3 years), 504 ECG recordings were obtained using the iECG. No new CVD events were observed. The iECG monitoring recorded ST-T abnormality in 4 subjects (19%), ST-T abnormality plus left bundle branch block in 1 subject (5%), bradycardia in 1 subject (5%), atrial fibrillation in 1 subject (5%), short PR interval in 1 subject (5%) and normal findings in 13 subjects (61%). The questionnaire results showed a 68% rating for satisfaction, 58% rating for comfort, 68% rating for device utility and 37% rating for lifestyle improvements brought about by device use. Conclusions: The iECG could serve as a useful support tool for monitoring heart health in Japanese workers residing abroad with risk factors of CVDs.(J Occup Health 2014; 56: 387-392)
Background and Objectives: Solvents used in production facility-affiliated private laboratories have been seldomly reported. This study was initiated to specify solvent use characteristics in private laboratories in comparison with the use in public research laboratories and on production floors. Elucidation of the applicability of conclusions from a public laboratory survey to private institutions is not only of scientific interest but also of practical importance. Materials: A survey on use of 47 legally stipulated organic solvents was conducted. The results were compiled for April 2011 to March 2013. Through sorting, data were available for 479 unit workplaces in private laboratories. Similar sorting for April 2012 to March 2013 was conducted for public research laboratories (e.g., national universities) and production floors (in private enterprises) to obtain 621 and 937 cases, respectively. Sampling of workroom air followed by capillary gas-chromatographic analyses for solvents was conducted in accordance with regulatory requirements. Results: More than one solvent was usually detected in the air of private laboratories. With regard to solvent types, acetone, methyl alcohol, chloroform and hexane were prevalently used in private laboratories, and this was similar to the case of public laboratories. Prevalent use of ethyl acetate was unique to private laboratories. Toluene use was less common both in private and public laboratories. The prevalence of administrative control class 1 (i.e., an adequately controlled environment) was higher in laboratories (both private and public) than production floors. Conclusions: Solvent use patterns are similar in private and public laboratories, except that the use of mixtures of solvents is substantially more popular in private laboratories than in public laboratories.(J Occup Health 2014; 56: 393-398)
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