Journal of Occupational Health最新文献

Recently, the incidence of pneumoconiosis has decreased due to strict dust control measures and environmental improvements in the workplace. The significance of other occupational diseases has relatively increased. Occupational hypersensitivity pneumonitis (OHP) is mainly caused by allergic reactions to antigens in the workplace. Therefore, the presence of subtle amounts of harmful substances in the environment can increase the risk of developing OHP. Not only organic substances but also inorganic substances can cause OHP. OHP is caused by a specific antibody reaction (type III allergy) or sensitized lymphocytes (type IV allergy) to a specific antigen. Based on the clinical course, OHP is classified into acute and chronic hypersensitivity pneumonitis (HP). Acute HP forms granulomas and is classified as a granulomatous lung disease (nonfibrotic HP), whereas chronic HP rarely forms granulomas and progresses to fibrosis (fibrotic HP). Differentiation between chronic HP and idiopathic or collagen vascular disease-related interstitial pneumonia is challenging. Additionally, the genetic background of each patient influences the onset, leading to diverse onset patterns. Antigens and modes of onset are diverse in the workplace. Therefore, diagnosis is difficult, and many patients may be misdiagnosed. Chronic HP with advanced fibrosis due to delayed antigen identification has a poor prognosis. This study aimed to present an overview of the causative antigens, diagnosis, prevention, and treatment of OHP to provide appropriate and timely medical attention.

Background: Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death worldwide, responsible for 3.5 million deaths in 2021. Effective preventive measures are needed. Forest bathing has been reported to have positive effects on the immune system. In addition, the clean air, mild climate, phytoncides, high oxygen concentration, and other elements of forests are expected to have benefits for respiratory diseases such as COPD. Based on the above background, this study used a randomized crossover design to examine the improving effects of forest bathing on inflammatory markers and subjective symptoms related to COPD.

Methods: Thirty male subjects aged 63.1 ± 7.5 years were recruited after obtaining informed consent. These subjects participated in day trips to a Japanese cypress forest park and to a city area of Nagano Prefecture as a control in June 2024. Blood samples were taken in the afternoon of each day before and after the walks. Concentrations of α1-antitrypsin (α1-AT), C-reactive protein (CRP), fibrinogen, and interleukin 6 (IL-6) in blood were measured. Percutaneous oxygen saturation (SpO2), the profile of mood states (POMS), and questionnaires for subjective fatigue and respiratory symptoms and sleep quality were carried out before and after each trip.

Results: Forest bathing significantly decreased the concentrations of blood CRP, α1-AT, IL-6, and fibrinogen, significantly increased SpO2, reduced subjective fatigue and respiratory symptoms, improved sleep and the scores of positive feelings, and reduced the scores for negative emotions in POMS.

Conclusions: Forest bathing may improve inflammatory markers, SpO2, and subjective symptoms related to COPD.

Objectives A simple method to evaluate clinically the sweating rate and the salt loss rate via sweating would enable the early detection of heat-related illness in workers. We measured K+ concentration in sweat and calculated the Na+/K+ ratio to evaluate its utility for estimating sweating rate and salt loss rate. We hypothesized that compared with single electrolyte concentrations, the Na+/K+ ratio would be less affected by the rapid evaporation of sweat. Methods Thirteen healthy males exercised on a bicycle ergometer in an artificial climate room, and their sweating rates and Na+ and K+ concentrations in sweat were measured. We also compared sealed and open methods of sweat collection, which respectively prevent or permit evaporation of sweat from the collection area. Results When sweating rate increased, Na+ concentration increased, and K+ concentration decreased. Na+ concentration and the Na+/K+ ratio were significantly lower among habitual exercisers. Sweating rate was more strongly associated with the Na+/K+ ratio than with Na+ concentration. Similarly, the calculated NaCl loss rate was more strongly correlated with the Na+/K+ ratio than with Na+ concentration. The open sweat collection method reliably demonstrated individual variation in the Na+/K+ ratio. Conclusions The Na+/K+ ratio is more accurate than Na+ concentration for predicting sweating rate and the calculated NaCl loss rate because it accounts for individual sweat variation. The Na+/K+ ratio is not influenced by sweat evaporation, and samples can be practically obtained by briefly applying absorbent paper to the skin surface.

Objectives: This study examines the cross-sectional association between relatively lower-intensity physical activity (LIPA) during leisure time and presenteeism, accounting for relatively higher-intensity physical activity (HIPA) during leisure time.

Methods: Data were derived from 11 438 workers from 6 worksites of large companies in Japan, which participated in a questionnaire survey conducted between fiscal years 2018 and 2020. Frequency and duration per occasion were assessed for leisure-time physical activities at 3 intensities as determined by shortness of breath. LIPA was defined as activity not causing shortness of breath. The participants were divided into 3 groups according to LIPA volume (none, <60 min/wk, or ≥60 min/wk) and into 2 groups according to HIPA volume (none or engaged). A single question assessed the participants' presenteeism through self-ratings of their work performance. A multivariable Poisson regression model with a robust variance estimator estimated prevalence ratios (PRs) of presenteeism and their 95% CIs across the categories for both LIPA and HIPA.

Results: The prevalence of presenteeism tended to decrease with increasing amounts of LIPA and HIPA (P for trend <.001). Among those who did not engage in HIPA, a significantly lower prevalence of presenteeism was observed among individuals who engaged in LIPA for ≥60 min/wk compared with those who did not (adjusted PR = 0.74; 95% CI = 0.68-0.81).

Conclusions: This study supports the protective role of LIPA during leisure time that does not cause shortness of breath against presenteeism among workers who do not engage in HIPA during leisure time.

Bromopropane was introduced commercially as an alternative to ozone-depleting and global-warming solvents. The identification of 1-bromopropane neurotoxicity in animal experiments was followed by reports of human cases of 1-bromopropane toxicity. In humans, the most common clinical features of 1-bromopropane neurotoxicity are decreased sensation, weakness in extremities, and walking difficulties. Moreover, decreased cognition, abnormal findings on brain magnetic resonance imaging, urinary incontinence, and numbness in the perineal area have also been described in workers exposed to 1-bromopropane. Murine histological studies showed that exposure to 1-bromopropane reduced the density of brain noradrenergic axons. Furthermore, proteome studies demonstrated 1-bromopropane-induced changes in the expression of proteins in the hippocampus of rats, similar to the changes seen in mice exposed to acrylamide, suggesting a common mechanism of electrophile-induced neurotoxicity. In addition to its neurotoxicity, 1-bromopropane also induces male reproductive toxicity in rats, although the targeted areas in the reproductive system differ from those affected by 2-bromopropane. However, exposure to high levels of 1-bromopropane was reported to induce spermatogenic cell degeneration, similar to that caused by 2-bromopropane, suggesting common mechanism(s) underlying 1- and 2-bromopropane-induced male reproductive toxicity. Plural approaches, including human, animal, and mechanistic studies, are useful for identification of 1-bromopropane neurotoxicity. The International Agency for Research on Cancer summarized that 1-bromopropane as well as 2-bromopropane share several key characteristics of carcinogens. Plural approaches can establish evidence-based preventive medicine by modification of the conventional evidence-based medicine (EBM), which has been developed for therapeutic medicine and is represented by the EBM pyramid.

In 2012, a social issue arose concerning a high incidence of cholangiocarcinoma (bile duct cancer) among printing workers. The cause was prolonged exposure to high concentrations of 1,2-dichloropropane that was included in the ink cleaning agent. Until then, it was not known that this substance could cause cancer in humans. The author was involved in this incident from the beginning. This article describes the course from the start of the investigation to the recognition of cholangiocarcinoma as an occupational disease. Furthermore, the article presents the pathological characteristics of occupational cholangiocarcinoma, as well as epidemiological analysis results.

Background: Shift work is associated with irregular dietary habits and poor nutritional intake, increasing the risk of chronic diseases. This study aimed to assess dietary quality and nutritional intake according to shift work status among Korean adult workers.

Methods: Data from 15 121 adult workers aged ≥20 years from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted between 2013 and 2021 were analyzed. Dietary quality was evaluated using the Korean Healthy Eating Index (KHEI), and shift work status was determined by self-reported working hours. Associations between shift work and dietary quality were assessed using multivariable logistic regression, accounting for the complex survey design. Stratified analyses by gender were also conducted.

Results: Shift workers showed no significant difference in overall dietary quality compared with day workers (odds ratio [OR] = 0.91; 95% CI, 0.80-1.04). However, shift workers more frequently skipped breakfast (OR = 0.78; 95% CI, 0.68-0.89) and consumed fewer fresh fruits (OR = 0.86; 95% CI, 0.75-0.98), vegetables excluding kimchi/pickles (OR = 0.89; 95% CI, 0.79-0.99), and protein-rich foods (OR = 0.87; 95% CI, 0.77-0.99). Conversely, shift workers had better adherence to recommended sodium intake (OR = 1.19; 95% CI, 1.06-1.34). Gender-stratified analysis revealed lower fruit intake among male shift workers and more frequent breakfast skipping and lower fruit/protein intake among female shift workers.

Conclusions: Among Korean adult workers, shift work was associated with unfavorable dietary patterns, characterized by increased breakfast skipping and lower intake of fruits, vegetables, and protein-rich foods. Tailored strategies to improve meal regularity and dietary balance are recommended for managing the health of shift workers.

Objectives: This systematic review aimed to synthesize the effectiveness of work ability interventions on productivity outcomes.

Methods: This systematic review was registered in PROSPERO (CRD42024541404) and conducted in accordance with PRISMA guidelines. In December 2024, a systematic search from 2000 onward was conducted using databases including EBSCO, ProQuest, Scopus, Web of Science, and PubMed. Two reviewers independently screened articles, assessed quality using risk-of-bias tools, and extracted data, with a third reviewer resolving any disagreements. The eligibility criteria were defined using population, intervention, comparison, outcomes, and study design (PICOS) elements.

Results: Of the 55 articles that underwent quality assessment, 26 were excluded due to high risk of bias. Among the remaining 29 articles, 24 were randomized controlled trials, of which 5 conducted economic evaluation, and 5 were nonrandomized controlled trials, collectively conducting 33 interventions. The results of the original studies showed that 5 work ability interventions had a statistically significant effect on productivity. Four interventions effectively reduced absenteeism, and 1 intervention increased the risk of absenteeism. One intervention indicated that the cost of absenteeism was reduced, and another showed that the intervention was more effective and less costly than usual occupational care.

Conclusions: Our analysis of work ability interventions showed that 28 interventions did not have an effect on productivity and only 5 interventions affected productivity. This systematic review highlights the limited evidence regarding evidence-based work ability interventions that affect productivity. Despite the importance of the topic, it remains understudied, and there is insufficient evidence to support decision-makers aiming to enhance productivity.

Objectives: Passenger rail drivers' physical behaviors contribute to individual, organizational, and community risks. As work tasks are theorized to determine physical behaviors performed during work hours, there is a need to clarify how work tasks determine passenger rail drivers' physical behaviors to inform improved work design. The aim of this study was to describe the physical behaviors of passenger train drivers across their work tasks and breaks, and explore what potential influences create variations in physical behaviors within tasks.

Methods: An exploratory observational field study was conducted with passenger train drivers in South Australia. Across a shift drivers were observed directly, and a hierarchical task analysis was conducted to identify their main work tasks and sub-tasks, with simultaneous accelerometry to quantify the physical behaviors.

Results: Ten male passenger train drivers, median age of 53 years, were observed. The hierarchical task analysis identified seven main tasks: Pre-Service, Set-Up, Driving, Switching Ends, Pack-Up, Waiting Time, and Breaks. Driving was almost all sitting (99%), whereas Set-Up and Switching Ends involved considerable moderate/vigorous physical activity (24% and 21%, respectively). Physical behaviors varied within tasks due to worker characteristics (eg, individual motivation), uncontrolled work elements (eg, weather), and structural work elements (eg, timetables).

Conclusions: Passenger train drivers' physical behaviors at work were largely determined by their work tasks, but varied with worker characteristics, as well as uncontrolled and structural work elements. These findings may be used to inform future job redesigns to promote passenger train drivers' health through their physical behaviors at work.

Objectives: Japan faces the need for occupational health management based on an understanding of workers' health and its impact on work productivity. Given a paucity of comprehensive studies, we conducted this study to investigate work productivity by diseases among workers of various occupations in Japan, by using a large-scale database.

Methods: This retrospective, descriptive study used pre-existing data derived from health insurance claims and 2 surveys conducted in 2021. The analysis included the data of ≥19-year-old current workers with response data to the questions regarding Work Productivity and Activity Impairment (WPAI). The WPAI of the target diseases, defined by claims diagnosis codes, was plotted against the 1-year prevalence of each disease. The cost of lost productivity was estimated based on the response data regarding the WPAI.

Results: Overall, 31 540 individuals participated, and the analysis showed that psychiatric disorders, headache, epilepsy, and insomnia had a high percentage of participants reporting any level of WPAI, although the prevalence of these diseases was low. We also explored the cost of lost productivity to supplement the interpretation of the overall impact of health problems; however, no clear trend was observed.

Conclusions: Many Japanese workers with psychiatric disorders, headaches, epilepsy, and insomnia have impaired work productivity and daily activities.