Journal of Occupational Health最新文献

Objectives: The natural fibrous mineral, asbestos, has been useful in industry for many centuries. In the 1960s, epidemiology recognized the association between asbestos exposure and mesothelioma, and in 1987 the International Agency for Research on Cancer designated all kinds of asbestos as Group 1 carcinogens. However, various scientific enigmas remained regarding the molecular mechanisms of asbestos-induced mesothelial carcinogenesis. This review article was undertaken to reveal and summarize recent discoveries to resolve those enigmas.

Methods: We collected recent important findings from our own laboratory and others to explain why mesothelial cells are the target for asbestos-induced carcinogenesis and what are the key molecular mechanisms.

Results: The long incubation period of 30-40 years for mesothelial carcinogenesis after asbestos exposure allows the asbestos fibers to go through the pulmonary parenchyma from the central to peripheral portions and ultimately reach the parietal mesothelium by piercing visceral pleura. Asbestos fibers have affinity for hemoglobin and histones, thus accumulating iron on the surface while traveling through the lung. Mesothelial cells are phagocytic cells, engulfing iron-coated asbestos fibers. Accordingly, homozygous deletion of the p16INK4a tumor suppressor gene, a signature of excess iron-induced carcinogenesis, is acquired through oxidative DNA damage. Recently, exosome-dependent iron transfer from asbestos-fed macrophages to mesothelial cells was reported. Similar molecular mechanisms are observed with multiwalled carbon nanotubes of ~50-nm diameter.

Conclusions: Physical dimensions, biopersistence, and affinity to iron/histones are essential for fibrous material to be carcinogenic to mesothelial cells. Therefore, local iron reduction may be a strategy to prevent mesothelial carcinogenesis.

Objectives: Firefighters are frequently exposed to psychologically and physically stressful experiences. This volatile occupational environment is thought to contribute to the risk of firefighter musculoskeletal disorders (MSDs). However, investigations of firefighter MSDs are limited, and to our knowledge, have not been collectively examined. The purpose of this novel systematic review was to systematically identify, critically appraise, and synthesize evidence regarding the relationship between MSDs and personal, physical, and psychosocial factors among career firefighters to guide future study directions.

Methods: Five electronic databases (MEDLINE, CINAHL, SPORTDiscus, APA PsychInfo, PubMed) were searched from inception to December 12, 2024, which yielded 741 results. This review followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 guidelines and used the AXIS (Assess the Quality of Cross-Sectional Studies) tool.

Results: The final review included 20 cross-sectional studies (AXIS scores 12-18). Of those, 19 examined physical factor(s), and 16 examined psychosocial factor(s). The overall evidence suggests a positive relationship between firefighter MSD reports and body mass index (BMI), occupational stress, and depression. A negative relationship to physical activity engagement was consistently observed.

Conclusions: Body mass index , physical activity, and occupational stress were the most consistently examined factors related to firefighter MSDs. Odds of MSD occurrences were positively related to occupational stress and BMI, and negatively related to physical activity engagement; therefore, future investigations can focus primarily on these factors in relation to MSD risk. The establishment of reliable and culturally appropriate MSD report forms among firefighters is warranted as data collected were heterogeneous and not directly comparable. Finally, this report suggests that prospective examinations of both physical and psychosocial factors related to firefighter MSDs are needed.

Objectives: Innovative technology at work can lead to stress and has been linked with adverse work and health consequences. This study aimed to examine the association of techno-insecurity and techno-strain with mental well-being in different age and occupational groups.

Methods: We used a nationally representative survey of the working population and restricted our analyses to 2814 employees who reported being engaged with new technology. Techno-insecurity and techno-strain were evaluated by a single question each. Mental health status was assessed by a 5-item scale, and burnout status was assessed by the Copenhagen Burnout Inventory. We used logistic regression analysis to examine the association of techno-insecurity and techno-strain with mental well-being, adjusting for job control, psychological demands, job insecurity, and workplace violence. We further stratified study participants by age and occupational group and examined the association in each group.

Results: One-fifth of the study participants reported having techno-insecurity and techno-strain. Techno-insecurity was associated with a 1.8-fold increased risk of poor mental health and high burnout, whereas techno-strain was associated with a 2.2-fold increased risk of having poor mental health and high burnout. The associations between techno-insecurity or techno-strain and poor mental health were most profound among middle-aged workers. Among all occupational groups, the associations between techno-insecurity or techno-strain and burnout were most profound among manual workers.

Conclusions: Techno-strain and techno-insecurity are emerging occupational mental health threats, particularly among middle-aged and manual workers. To promote mental health, resources provided by the organization are needed to help employees cope and work with technology.

The novel properties and functions of nanomaterials have naturally alerted toxicologists to the fact that such materials may also have novel effects on the human body and other living organisms. In particular, materials with high stability or biopersistency have been shown to have a tendency to accumulate in the body, leading to chronic toxicity including carcinogenicity. However, in the early stages of toxicity research, the information is often limited to the effects of short-term exposure studies, and findings on chronic effects are very much delayed. In this context, it was exceptional that studies on multi-walled carbon nanotubes (MWCNTs) have started with the verification of their potential to induce mesothelioma. This toxicological endpoint was expected on the basis of existing knowledge of asbestos and asbestos-like fiber particles. This movement has led to the achievement of the original mission of "modern toxicology," which is "to achieve a win-win situation where both industrial promotion and safety assurance are ensured by communicating and sharing toxicity information to developers and consumers at a stage before mass production and consumption begins, that is, before massive exposure of the general public begins." Inaccurate toxicity assessments of asbestos in the 1980s and 1990s allowed its spread to our living environment, which is difficult to decontaminate, and the damage continues to this day. However, the case described here could be an example of realizing the proposition that "nanomaterials, the flagship of high technology, must not repeat the same mistakes."

Objectives: Performing chest compressions in high-temperature environments may increase the physiological strain on rescuers, potentially affecting the quality of cardiopulmonary resuscitation (CPR). This study aimed to examine the effects of environmental temperature on physiological responses, perceived exertion, and chest compression performance.

Methods: Twenty male participants performed 10 minutes of chest compressions under 2 temperature conditions: 35°C (HOT) and 25°C (CON). Physiological parameters, including rectal temperature (Tre), skin temperature, heart rate (HR), and rating of perceived exertion (RPE), were measured. The number of successful chest compressions was also recorded.

Results: The results indicated no significant differences in Tre, heart rate, or RPE during chest compressions between HOT and CON. However, Tre showed a tendency to increase continuously during the recovery phase at 35°C. HR decreased during recovery in both conditions but remained elevated at 35°C compared with resting levels. A significant interaction effect was observed in mean skin temperature, suggesting different thermoregulatory responses between HOT and CON.

Conclusions: These findings suggest that although subjective exertion and cardiovascular responses may not differ significantly, prolonged exposure to high temperatures could influence thermoregulation in rescuers. Future research should explore the long-term impact of heat stress on CPR performance and rescuer safety.

Background: To date, no studies have investigated the relationship between one's dominant hand and neck/shoulder pain. The aim of this prospective cohort study was to explore the relationship between one's dominant hand and the severity of neck/shoulder pain. We also examined the relationship between the dominant hand and the onset of neck/shoulder pain at follow-up among workers without neck/shoulder pain at baseline.

Methods: We conducted a prospective cohort study of 9451 workers. The dominant hand was measured by 10 items from the Japanese version of the Flanders Questionnaire at the baseline survey. We assessed neck/shoulder pain using a numeric rating scale. We calculated the unstandardized coefficient (B) using multiple regression analysis and the incidence rate ratio (IRR) for neck/shoulder pain using modified Poisson regression among workers who were free of neck/shoulder pain at baseline.

Results: Among the 9451 respondents for the baseline survey, 6156 responded to the follow-up survey (response rate: 65.1%). Mixed-handed workers reported a higher degree of neck/shoulder pain than right-handed workers (B, 0.33; 95% CI, 0.09-0.58). Among 2481 participants, mixed-handed workers also had a higher IRR for neck/shoulder pain (IRR, 1.27; 95% CI, 1.01-1.61). There was no difference in any of the left-handers compared with the right-handers.

Conclusions: The study found that mixed-handed workers had higher levels of neck/shoulder pain than right-handed workers, and the incidence rate was also higher among mixed-handed workers. Employers should consider these findings when designing work environments, managing tasks, and providing occupational health training to optimize worker comfort and safety.

Objectives: Use of commercially available mobile health (mHealth) applications in supporting lifestyle improvements has become popular in recent years. However, the effectiveness of advice promoting the use of such applications based on individual behavioral goals in a health guidance setting remains unclear. This study explored how guiding participants of the Specific Health Guidance (SHG) program, a Japanese public health initiative to prevent cardiovascular disease, to use commercially available mHealth applications impacted their application usage, lifestyle habits, and cardiovascular risk factors.

Methods: In this multicenter, randomized, open-label, parallel-group comparison study, 156 individuals with a history of SHG participation and who were engaged in the Motivational Health Guidance program (a type of SHG) in 2021 were assigned to intervention (n = 76) or control (n = 80) groups. Whereas both groups received standard guidance, the intervention group also received recommendations for mHealth applications based on their individual behavioral goals. The participants' application usage, behavioral changes, and body weight were assessed after 3 months, with health checkup data evaluated after 1 year.

Results: The proportion of mHealth application users after 3 months was significantly higher in the intervention group (68.4%) than in the control group (40.0%). The intervention group also reported a significantly greater weekly frequency of mHealth application usage. Moreover, the intervention group reported a significantly decreased change in triglyceride levels after 1 year compared with the control group.

Conclusions: Recommending commercially available mHealth applications in a health guidance setting significantly increased the number of mHealth application users and their frequency of use.

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.