Journal of Occupational Health最新文献

N,N-Dimethylacetamide (DMAC), which is widely used as an industrial solvent, can be absorbed via the respiratory tract and skin of humans exposed to DMAC. Hepatotoxicity is a main health risk of DMAC exposure in humans, and the relevant cases and epidemiological studies are reviewed herein. No hepatotoxicity was identified in workers exposed to approx. 3-ppm DMAC, and among workers exposed to > 9-ppm DMAC the DMAC exposure was not observed to contribute significantly to the liver damage. However, a case of liver damage was identified in which the calculated 8-hour weighted average was 12.8 mg/m3 (3.6 ppm). The skin absorption notation for DMAC is indicated based on human volunteer studies. The evidence regarding DMAC's potential carcinogenicity in humans is not sufficient, and our literature search identified no report of DMAC as a reproductive toxicant in humans. Further case reports and epidemiological studies are necessary to determine the acceptable DMAC exposure limit for workers and thus protect them from DMAC's toxicity.

N,N-Dimethylacetamide (DMAC), which is widely used as an industrial solvent, can be absorbed via the respiratory tract and skin of humans exposed to it. Hepatotoxicity is a main health risk of DMAC exposure in humans, and the relevant cases and epidemiological studies are reviewed herein. No hepatotoxicity was identified in workers exposed to ~3 ppm DMAC, and among workers exposed to >9 ppm DMAC the DMAC exposure was not observed to contribute significantly to liver damage. However, a case of liver damage was identified in which the calculated 8-hour weighted average was 12.8 mg/m³ (3.6 ppm). The skin absorption notation for DMAC is indicated based on human volunteer studies. The evidence regarding DMAC's potential carcinogenicity in humans is not sufficient, and our literature search identified no report of DMAC as a reproductive toxicant in humans. Further case reports and epidemiological studies are necessary to determine the acceptable DMAC exposure limit for workers and thus protect them from DMAC's toxicity.

Objectives: The objective of the current study was to elucidate the relationship between blood cadmium (Cd-B) levels and proximal tubular dysfunction using urinary β2-microglobulin (B2M-U) as an indicator among workers in nickel-cadmium battery plants in Japan.

Methods: Medical check-up data from 338 workers exposed to cadmium at 2 plants were collected from 1997 through 2020. Workers with at least 2 check-ups were included, excluding those with other renal dysfunctions. Proximal tubular dysfunction was defined as a B2M-U of 300 μg/g creatinine or higher in 2 or more consecutive check-ups. A multivariable Cox proportional-hazards regression model with time-dependent covariates was performed to analyze the relationship between Cd-B levels and the time to onset of proximal tubular dysfunction, adjusting for age, sex, and smoking history.

Results: Of the 338 workers, 238 met the study eligibility criteria for the analyses. The geometric mean of Cd-B was 1.97 μg/L. The Cox proportional hazards analysis demonstrated that higher time-dependent Cd-B levels were significantly associated with an increased risk of proximal tubular dysfunction, with a hazard ratio of 1.17 (95% CI: 1.06-1.29).

Conclusions: Higher Cd-B levels are associated with an increased risk of proximal tubular dysfunction in workers exposed to cadmium, indicating an increased risk of renal disease under the current industrial health management in Japan. Continuous monitoring and improved management of cadmium exposure are necessary to protect workers' health even in developed countries such as Japan.

Objectives: Our aim was to report integrative evidence for the health risk assessment of ortho-toluidine (OT) in bladder cancer in a mini-review of the recent studies of humans, experimental animals, and OT skin permeability.

Methods: Bladder cancer cases were identified in workers in Japan who were occupationally exposed in 2014-2017 to aromatic amines, primarily to the human carcinogen OT.

Results: A key epidemiological study of 98 aromatic amine-exposed workers in Japan showed a clear OT exposure-response relationship with a standardized incidence ratio. A rat model experimental study also indicated that OT and acetoaceto-o-toluidine are potent bladder carcinogens. Multiple mechanisms of OT-related bladder cancer have been proposed: metabolic activation to reactive metabolites that bind DNA and proteins, mutagenicity, oxidative DNA damage, chromosomal damage, and cytotoxicity by OT. Recent comprehensive analyses of DNA adducts in rats identified a number of common oxidative DNA adducts, including 8-OHdG, in the rat urothelium and indicated that oxidative stress may play a crucial role in the development of urinary cancer caused by OT. The skin permeability of 6 aromatic amines (o-toluidine, aniline, p-toluidine, o-anisidine, 2,4-dimethylaniline, and o-chloroaniline) was examined with the use of a 3-dimensional (3D) reconstructed human skin model; ~70%-80% of the 6 aromatic amines had permeated through the 3D skin within 8 hours. Genotoxic potency testing in a human urothelial cell line using γ-H2AX, a marker of DNA damage, suggested that OT exhibited strong γ-H2AX generation.

Conclusions: Prolonged dermal exposure to OT along with other genotoxic aromatic amines over many years may contribute to the development of bladder cancer.

Objectives: This study aimed to investigate the impact of perceived workplace health support (PWHS) on absenteeism and presenteeism among Japanese workers to determine the significance of health and productivity management in improving labor productivity.

Methods: This prospective cohort study, using data from the Work Systems & Health Internet Research (WSHIR) study, involved 1879 Japanese workers aged 20-69 years. The intensity of PWHS was assessed using self-administered questionnaires. The participants were followed up from October 2021 to October 2022 to evaluate the incidence of absenteeism and presenteeism based on the level of PWHS.

Results: The study findings revealed that higher PWHS significantly correlated with lower presenteeism, indicating better work productivity. Conversely, the relationship between PWHS and absenteeism was less clear, with no consistent trend observed across different levels of PWHS intensity.

Conclusions: Enhanced PWHS was associated with reduced presenteeism among Japanese workers, underscoring the importance of workplace health support for improving employee productivity. This finding emphasizes the need for companies to focus on health promotion activities and recognize the potential of PWHS as a performance indicator in corporate health management.

Objectives: Previous research has indicated that shift workers exhibit fewer healthy behaviors than those working regular daytime hours. Although health literacy influences health behaviors, studies comparing health literacy levels between shift and fixed-day workers and investigating whether differences in health behaviors between these 2 groups are mediated by health literacy are lacking.

Methods: This cross-sectional study used a self-administered questionnaire in a large-scale manufacturing company. Overall, 2152 manual workers aged 18-64 years were enrolled in this study (961 and 1191 fixed-day and shift workers, respectively). Logistic regression structural equation models were used for analyzing the mediating role of health literacy in the relationship between shift work and health behaviors.

Results: Shift and fixed-day workers did not show differences in age-adjusted health literacy. Compared with fixed-day workers, the odds ratios of shift workers for leisure time exercise, not currently smoking, having breakfast, brushing their teeth, and eating green and yellow vegetables were 0.85 (95% CI, 0.70-1.02), 0.68 (95% CI, 0.56-0.80), 0.63 (95% CI, 0.52-0.76), 0.79 (95% CI, 0.65-0.95), and 0.58 (95% CI, 0.48-0.70), respectively. Mediation analysis showed that the odds ratios of the direct effects of shift work on favorable habits were almost the same as the total effect.

Conclusions: This study observed that health literacy did not mediate health behavior and shift work. Further research is needed to clarify the causes of these differences.

Objectives: To examine the utility of the FIB-3 index as a secondary screening tool for liver fibrosis in workplace-based health checkups, by comparing its concordance and negative predictive values (NPVs) with those of the FIB-4 index.

Methods: This cross-sectional study included 12 622 workers from the Hitachi Cohort Study who underwent workplace-based health checkups between April 2021 and March 2022. FIB-4 was calculated using age, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and platelet count, whereas FIB-3 used the same components except age. To evaluate the utility of FIB-3 in excluding liver fibrosis, NPVs were calculated using FIB-4 thresholds (1.30, 2.01, and 2.67) as references. Concordance between FIB-3 and FIB-4 was examined across different age groups. In addition, multivariate logistic regression analysis was conducted to identify factors associated with false-positive FIB-3 results.

Results: The FIB-3 index demonstrated high NPVs for excluding liver fibrosis, with values of 99.9% at FIB-4 ≥ 1.30 and 98.2% at FIB-4 ≥ 2.67. Strong concordance between FIB-3 and FIB-4 was observed consistently across different age groups. Among participants with elevated ALT (>30 IU/L), FIB-3 consistently ruled out fibrosis, whereas FIB-4 positivity increased with advancing age. Multivariate analysis indicated that higher AST levels and increased alcohol intake were significantly associated with false-positive FIB-3 results.

Conclusions: The FIB-3 index demonstrated stable performance across age groups while maintaining high concordance and NPV relative to FIB-4. These findings suggest that FIB-3 may serve as a practical screening tool in routine workplace-based health checkups, particularly in mitigating age-related overestimation observed with the FIB-4 index.

Objectives: This study aimed to clarify the primary preventive effects of physical activity interventions delivered through digital health technology (DHT) on workers' mental health symptoms, and to examine the conditions of attrition and adherence in these interventions.

Methods: We examined randomized controlled trials (RCTs) that analyzed the effects of physical activity interventions delivered through DHT on workers' health outcomes. We included RCTs published in English or Japanese since 2010 and excluded studies that targeted specific diseases or secondary and tertiary prevention. We conducted the search on July 25, 2023, using Cochrane CENTRAL, Embase, PsycINFO, PubMed, and Ichushi-Web, and citation searches. We assessed risk of bias using the Cochrane Risk of Bias Tool version 2, and data were integrated using a random-effects model. Attrition rates were averaged, and adherence was qualitatively reviewed.

Results: Eight studies were included in the systematic review, and 5 in the meta-analysis. Pooled effect sizes immediately after intervention were as follows: Cohen d = -0.51 (95% CI, -0.75 to -0.27) for depression and negative affect, and -0.36 (95% CI, -0.60 to -0.05) for perceived stress. The attrition rate was 16.8% and 12.4% for the control and intervention groups, with only 2 studies providing details on adherence.

Conclusions: Physical activity interventions delivered through DHT may moderately improve depression and negative affect, and slightly reduce perceived stress among workers. However, these findings should be interpreted with caution due to the limited number of studies and low evidence certainty. Future studies should explore long-term effects, additional mental health outcomes, and factors affecting adherence.

Objectives: This study explored the relationship between fear of future workplace violence (FFWV) and burnout, and the moderating effect of psychological resilience on this relationship.

Methods: We recruited 413 pediatricians from 26 specialized and general hospitals in China's Shandong provinces and Ningxia Hui Autonomous Region from August 2021 to April 2022. Fear of future workplace violence was measured using the Fear of Future Violence at Work Scale. Burnout was assessed using the Maslach Burnout Inventory. Psychological resilience was measured using the 10-item Connor-Davidson Resilience Scale. A multiple linear regression analysis was used to investigate the relationship between FFWV and burnout. The SPSS PROCESS macro was used to examine the moderating effect of psychological resilience on this relationship.

Results: About 85.7% of pediatricians experienced a medium or high level of fear. Fear of future workplace violence was significantly and positively associated with emotional exhaustion, depersonalization, and personal accomplishment (B = 0.23, SE = 0.39, P < .001; B = 0.06, SE = 0.13, P < .001; B = 0.17, SE = 0.03, P < .001, respectively, where B denotes the unstandardized regression coefficient). The interaction effects of FFWV and psychological resilience on emotional exhaustion (B = -0.008; 95% CI, -0.01 to -0.004) and depersonalization (B = -0.003; 95% CI, -0.005 to -0.001) were statistically significant. The protective effect conforms to the "protective-stabilizing" model.

Conclusions: Psychological resilience training may be beneficial for pediatricians in preventing high levels of emotional exhaustion and cynicism resulting from FFWV.