Objectives: To test the reliability of the procedures (described in a previous article) for estimation of biological occupational exposure limits (BOELs). Methods: Data on four organic solvents (styrene, ethyl benzene, isopropyl alcohol and tetrachloroethylene) were obtained from recent publications and added to previously cited data for 10 organic solvents. Regression analysis was used for statistical evaluation. Results and Discussion: The previously reported results obtained using 10 solvents were reproduced by the analysis with 14 solvents. Repeated randomized division of the 14 sets into two subgroups of equal size followed by statistical comparisons did not show a significant difference between two regression lines. This reproducibility suggests that the procedures used to estimate BOELs may be applicable across many solvents, and this may be of particular benefit for protecting the health of workers who work with skin-penetrating solvents.
Objectives: This study investigated potential associations between having a person in need of nursing care at home and psychological distress amongst the Japanese working population, using a nationally representative sample. Methods: We extracted data from the 2013 Comprehensive Survey of Living Conditions conducted by the Ministry of Health, Labour and Welfare of Japan. The original survey was conducted amongst 295,367 households in 5,530 randomly selected municipalities. We analyzed participants aged 25-65 years who headed a household. The original questionnaire included questions about the specific qualifications required to receive long-term care insurance benefits, about psychological distress (measured using the K6 scale), and other covariates. If a family contained a member in need of nursing care at home, the person who headed that household was recognized as the participant who had a person in need of nursing care at home. Multiple logistic regression analysis was conducted to investigate the association between having a person in need of nursing care at home and psychological distress. Results: A total of 36,193 men and 2,765 women were included in the analysis, 2.9% of whom had a person in need of nursing care at home. Statistical analysis revealed an association between having a care-requiring older relative at home and psychological distress (odds ratio: 1.40, 95% confidence interval: 1.01-1.93). Conclusions: Having a person in need of nursing care at home appears to be positively correlated with worsening mental health of working populations in Japan.
Objectives: Shift workers are at an increased risk of diet-related chronic conditions. We aimed to investigate dietary intake and dinner timing among shift workers. Methods: A questionnaire survey was administered to the employees of 43 companies in Japan between December 2013 and February 2014. The dietary intake of workers was assessed through a validated food frequency questionnaire (FFQ). Nutrient intake was evaluated by adjusting the total energy intake using a nutrient residual model. Analysis of covariance was used to obtain the means of total energy and nutrient intake by the work schedule (shift or daytime), and the means of total energy and nutrient intake by dinner timing (regular or irregular). Results: Valid responses were obtained from 2,062 daytime and 302 shift workers. A valid response rate to the FFQ was slightly but significantly lower among shift workers than among daytime workers (87.1% and 91.8 %). When compared to daytime workers, shift workers were more likely to eat dinner at irregular times (46.7% vs. 3.6%). Shift work was associated with a higher mean body mass index (23.4 kg/m2 vs. 22.3 kg/m2), a higher proportion of being overweight (27.7% and 18.8%), higher total energy intake, and lower intakes of dietary fiber, vitamin B2, folic acid, vitamin C, potassium, calcium, magnesium and iron. Moreover, irregular dinner timing was associated with lower intakes of protein, folic acid, and zinc in daytime workers, and lower intakes of carbohydrate and copper in shift workers. Conclusions: These findings indicate a need to improve the diet of shift workers.
Objective: The current study investigated the additive effect of oral lead (Pb) exposure and dietary iron (Fe) deficiency on intestinal lactobacilli, E. coli, and yeast in SD rats. Methods: Weanling rats were fed on control diet (CD) or iron deficient diet (ID) for 4 weeks, followed by oral Pb exposure for another 4 weeks. Lead exposure was withdrawn for 2 weeks, and then resumed after 2 weeks. Blood samples were collected to determine haemoglobin (Hb), serum iron, blood Pb and δ-Aminolevulenic acid dehydratase (ALAD) activity. Fecal samples were collected to enumerate the lactobacilli, E. coli and yeast population on selective agar media and determine Pb levels. Results: Hb and serum Fe levels decreased significantly in iron deficient rats. Pb exposed rats had a significant increase in blood Pb levels and decreased ALAD activity. The lactobacilli population was significantly decreased (p<0.05) in ID rats compared to the CD group. Further, a significant decrease in the lactobacilli population was observed in Pb exposed rats irrespective of the dietary regimen. Upon withdrawal of Pb exposure, lactobacilli increased significantly in both the CD+Pb and ID+Pb groups, whereas re-exposure to Pb decreased lactobacilli population. The E. coli and yeast populations were inconsistent among both the ID and Pb exposed rats compared to controls. Fecal Pb levels increased significantly in Pb exposed rats irrespective of diet. Conclusion: An additive effect of dietary Fe deficiency and oral Pb exposure resulted in greater reductions in the intestinal lactobacilli population compared to either treatment alone. In addition, transient withdrawal of Pb exposure led to improved lactobacilli population irrespective of Fe status.
Objective: To investigate associations of work-related stressors and their changes over time with the risk of developing metabolic syndrome (MetS) among Japanese manufacturing workers. Methods: Participants were 1,040 employees aged 19 to 68 years who were free from MetS at baseline and completed the three year-interval follow-up survey. MetS was defined according to the Joint Interim Statement. Work-related stressors (job strain, job demands, job control, and worksite social support) were assessed based on the Job Content Questionnaire and were split into two categories (low and high) by the median value at each survey. Multivariable logistic regression was performed to investigate the associations of baseline work-related stressors and their changes over time with the incidence of MetS. Results: Three years later, 61 workers developed MetS. Higher job demands at baseline were significantly associated with a lower risk of MetS (adjusted odds ratio 0.46, 95% confidential interval: 0.24, 0.89). In the analyses of the changes in stressors over time, those whose job demands changed from low to high showed significantly higher risk of MetS (adjusted odds ratio 3.27, 95% confidential interval: 1.46, 7.34), compared with those who reported low job demands in both surveys. Conclusions: Results suggest that an increase in job demands over time, but not higher job demands at baseline, is associated with increased risk of MetS.
Objective: Occupational diseases (OD) are among the most significant issues of work life, with economic, medical, social, and ethical aspects. The majority of studies concerning OD focus on the causes or medical outcomes of OD. There are a limited number of studies investigating the social and economic impacts of being diagnosed with an OD. One of the important social aspects of OD is the employability of workers after an OD diagnosis. The aim of this study is to evaluate the changes in employment status after the OD diagnosis process. Methods: This is a cross sectional study. There were 204 eligible cases, and 198 (97%) completed the study. The study data were obtained from patient files, including OD Committee reports and questionnaires applied via telephone interview. Results: Among the 198 applicants, 170 (85.9%) were male and 146 (73.7%) were diagnosed with an OD. Of these workers, 106 (53.5%) had quit their current jobs. Of those workers, 89 out of 106 were in the OD group, and 17 were in the non-OD group. Diagnosis with OD (OR: 3.1 CI: 1.4-6.8) and non-union membership (OR: 11.1 CI: 5.2-23.5) increased the likelihood of quitting the job after an OD diagnosis. Conclusion: The short-term prognosis of OD was relatively poor. OD diagnosis or even referral to an outpatient clinic may cause quitting the job. Policies should account for the risk of unemployment after an OD diagnosis, and OD surveillance systems should obtain data on the employment status of workers following diagnosis.
Objectives: To clarify the priority given to periodical medical examination items among occupational physicians in Japan. Methods: Sixty-two occupational physicians who participated in this study selected statutory and non-statutory items within two types of budget plans: one lower (8,500 yen) than the total fee of statutory medical examinations (9,250 and 11,290 yen), and the other higher (12,000 yen) than the total fee. Medical fee points were used to set the cost of each medical examination item. A three round Delphi method was used from May to July 2016 to clarify the consensus opinion of occupational physicians. Results: The statutory items (selection rate: between 66 and 100%), except for waist circumference (15%) and sputum examination (0%), and serum creatinine (58%, non-statutory item) were included in the smaller budget plan (8,500 yen). In the larger budget plan (12,000 yen), the statutory items (selection rate: between 92 and 100%), except for waist circumference (39%) and sputum examination (0%), and some non-statutory items, namely serum creatinine (95%), leukocytes (92%), uric acid (89%), and fecal occult blood reaction (81%), had a selection rate over 80%. In addition, statutory items with higher accuracy were preferred, which included the following: air conduction pure-tone audiometry (92%), imaging diagnosis of thoracic X-ray examinations by a specialist (97%), glycated hemoglobin levels (98%), and electrocardiogram assessment by a specialist (100%). Conclusion: The statutory items, except for waist circumference and sputum examination, and some of the non-statutory items (e.g., serum creatinine) were given higher priority among occupational physicians in Japan.
Objective: We assessed the cancer risks resulting from the exposure to chromium, hexavalent chromium (Cr (VI) ), oxidic nickel (Ni), and soluble Ni in welding fumes during pipeline and shipyard construction and pressure container manufacturing in Taiwan. We also determined the roles of welding performance and demographic characteristics during the exposure to Cr and Ni. Methods: Personal air samples were collected for the analysis of Cr and Ni, and the concentrations of Cr (VI), oxidic Ni, and soluble Ni were quantified. We assessed cancer slope factors for Cr, Cr (VI), oxidic Ni, and soluble Ni, and we used the Incremental Lifetime Cancer Risk model proposed by the United States Environmental Protection Agency to calculate excess risk. Results: The risks of exposure to Cr and Cr (VI) in welding fumes exceeded the acceptable level of occupational exposure (10-3). We ranked the excess cancer risk in three industries in decreasing order as follows: pipeline construction, shipyard construction, and pressure container manufacturing. The most sensitive parameters for the risk assessment were Cr and Ni concentrations. Statistically significant determinants of Cr (VI), oxidic Ni, and soluble Ni concentrations were the following: stainless steel as the base metal and the filler metals of shielded metal arc welding (SMAW) and of gas tungsten arc welding (GTAW). Conclusion: The study revealed that welders belong to a high cancer-risk group. Furthermore, we demonstrated the roles of filler metals and stainless steel in exposure to Cr and Ni.