Background High-speed train engineers' lower extremities are constrained by compulsive vigilance pedal tasks and limited space beneath the control console during driving. Shifts in alertness triggered by running route observation may share the same mental resource required by moderate-to-low physical exertion. Current research on improving cab design and maintaining optimal on-duty attention allocation remains limited. Objective To examine variations in lower extremity muscle load, gaze-tracking behavior, and driving performance under various combinations of vigilance pedal positions and route scenarios during simulated high-speed train tasks. To identify optimal working condition combinations that promote level and variety of physical activity and facilitate rational attention allocation. Methods A 4×2 within-subjects design were employed (4 vigilance pedal position profiles: knee front, side, and any; 2 route scenarios: monotonous and complex). Nine male college volunteers were recruited as simulated drivers to perform designated interval driving tasks. Surface electromyography and eye tracking were used to assess leg muscle load and gaze behavior respectively. Task performance and subjective fatigue were recorded. Results In all simulation driving tasks, skeletal muscle loads were low with the percentage of maximum voluntary contraction (%MVC) at approximately 4%. No fatigue tendencies were observed within single trial blocks (7 min), and the subjective fatigue ratings remained relatively low. While the activation of the dominant-side tibialis anterior was higher for the knee pedal than for the front (%MVC: 3.7% ± 3.13% vs. 1.08% ± 0.72%) or the side pedals (%MVC: 3.7% ± 3.13% vs. 1.4% ± 0.77%). The activation level of the dominant-side gastrocnemius was higher for the knee pedal than for the other three pedal profiles. For the any pedal condition, the intercept of the instantaneous median frequency curve for the dominant-side rectus femoris was lower in the monotonous route than in the complex route [(111.18 ± 35.78) Hz vs. (153.33 ± 39.12) Hz]. Among eye-tracking metrics, total fixations were higher during knee-level pedaling than side pedaling, while more saccades were recorded in monotonous routes than in complex ones. Regarding task performance, the any pedal yielded fewer missed signals than the front pedal, with 2/3 and 1/3 of participants preferring the front and knee pedals, respectively. The activation levels of the dominant tibialis anterior and dominant gastrocnemius muscles during the knee pedal × complex route combination were higher than any combination involving the front pedal. No statistically significant effect of pedal position or route scenario was found on other indicators. Conclusion The combination of knee pedal and complex route provides an optimal working setting for maximizing leg muscle mobility without compromising attention allocation or driving performance. It is recommended that train engineers modulate attention during monotonous routes to avoid emotional tension and increased muscle strain caused by over-monitoring. Given the ergonomic characteristics of high cognitive load, low physical exertion levels, and highly restricted lower limb mobility among high-speed train engineers, future cab designs should consider incorporating knee-level vigilance pedal and adjust safety alertness rules to allow reset via either front or knee pedal.

Background High-speed train engineers' lower extremities are constrained by compulsive vigilance pedal tasks and limited space beneath the control console during driving. Shifts in alertness triggered by running route observation may share the same mental resource required by moderate-to-low physical exertion. Current research on improving cab design and maintaining optimal on-duty attention allocation remains limited. Objective To examine variations in lower extremity muscle load, gaze-tracking behavior, and driving performance under various combinations of vigilance pedal positions and route scenarios during simulated high-speed train tasks. To identify optimal working condition combinations that promote level and variety of physical activity and facilitate rational attention allocation. Methods A 4×2 within-subjects design were employed (4 vigilance pedal position profiles: knee front, side, and any; 2 route scenarios: monotonous and complex). Nine male college volunteers were recruited as simulated drivers to perform designated interval driving tasks. Surface electromyography and eye tracking were used to assess leg muscle load and gaze behavior respectively. Task performance and subjective fatigue were recorded. Results In all simulation driving tasks, skeletal muscle loads were low with the percentage of maximum voluntary contraction (%MVC) at approximately 4%. No fatigue tendencies were observed within single trial blocks (7 min), and the subjective fatigue ratings remained relatively low. While the activation of the dominant-side tibialis anterior was higher for the knee pedal than for the front (%MVC: 3.7% ± 3.13% vs. 1.08% ± 0.72%) or the side pedals (%MVC: 3.7% ± 3.13% vs. 1.4% ± 0.77%). The activation level of the dominant-side gastrocnemius was higher for the knee pedal than for the other three pedal profiles. For the any pedal condition, the intercept of the instantaneous median frequency curve for the dominant-side rectus femoris was lower in the monotonous route than in the complex route [(111.18 ± 35.78) Hz vs. (153.33 ± 39.12) Hz]. Among eye-tracking metrics, total fixations were higher during knee-level pedaling than side pedaling, while more saccades were recorded in monotonous routes than in complex ones. Regarding task performance, the any pedal yielded fewer missed signals than the front pedal, with 2/3 and 1/3 of participants preferring the front and knee pedals, respectively. The activation levels of the dominant tibialis anterior and dominant gastrocnemius muscles during the knee pedal × complex route combination were higher than any combination involving the front pedal. No statistically significant effect of pedal position or route scenario was found on other indicators. Conclusion The combination of knee pedal and complex route provides an optimal working setting for maximizing leg muscle mobility without compromising attention allocation or driving performance. It is recommended that train engineers modulate attention during monotonous routes to avoid emotional tension and increased muscle strain caused by over-monitoring. Given the ergonomic characteristics of high cognitive load, low physical exertion levels, and highly restricted lower limb mobility among high-speed train engineers, future cab designs should consider incorporating knee-level vigilance pedal and adjust safety alertness rules to allow reset via either front or knee pedal.

Background The neck, shoulders, and lower back are the primary affected areas of work-related musculoskeletal disorders. In manual tasks, combinations of hand functional height (defined as working height below the waist), awkward postures, and cognitive load are common risk factors. However, there is limited literature documenting how these factors specifically alter biomechanical load on the neck, shoulders, and lower back when working at hand functional height. Objective To explore quantitative differences in biomechanical load on the neck, shoulders, and lower back of workers performing manual tasks at hand functional height under different postures and cognitive load combinations. Methods A 3x2 within-subject design was implemented, with three postures (squat, kneeling, and stoop) and two levels of cognitive load (with cognitive load induced by a 2back task and without cognitive load). Ten male university students were recruited to perform a predetermined assembly task (a sequence of loosening and tightening screws) at hand functional height. Surface electromyography (sEMG) and 3D motion capture system were employed to assess the participants’ trunk biomechanical load in executing the tasks. Additionally, subjective perception, including fatigue, muscle pain, and cognitive load, were evaluated using scales. Results Significant variations in biomechanical load were observed across the three postures (P<0.05). The stoop posture exhibited the lowest muscle activation in most target muscles, except for the sternocleidomastoid, and showed the fastest decline in instantaneous median frequency (IMF) of the erector spinae, with a rate of (-0.050±0.008) Hz per unit time (0.128 s), and the greatest trunk flexion angle (35.14°±4.40°). Performing the task by squatting resulted in the highest muscle activation, especially in the upper trapezius, where maximum voluntary contraction percentage reached 20.07%±1.26%. In addition, the squatting posture also resulted in larger joint angles in the sagittal plane for the neck (−7.03°±2.70°), shoulders (60.20°±7.89°), and lower back (34.42°±4.20°). The kneeling posture showed intermediate muscle activation, the slowest IMF decline for the erector spinae in the lower back (−0.005±0.008) Hz per unit time (0.128s), and the joint angles were closest to neutral. The task performance results were also superior in the kneeling posture. Regarding cognitive load, no significant differences were found for most biomechanical indicators, except for subjective cognitive load scores, neck flexion, and shoulder external rotation angles. Conclusion In assembly tasks performed at hand functional height, kneeling results in moderate biomechanical load on the neck, shoulders, and lower back while also improves task performance compared to squatting and forward bending. Additionally, no significant effects of cognitive load under the 2back condition on biomechanical load are observed.

Background The Belt and Road Initiative is promoting the growth of the cross-border population, and there is still a lack of study on modifiable factors associated with health-related preventive behaviors among resident aliens in China. Public health events may highlight the relevant factors. Objective To conduct a pilot study to preliminarily identify potential modifiable factors associated with preventive behaviors among resident aliens in China, and to explore possible mediating effects of positivity and self-efficacy on the relationship between satisfaction of health services and preventive behaviors, aiming to provide ideas for further research in this direction. Methods A cross-sectional survey was conducted among foreigners in a city of East China by using snowball sampling in July 2023. Based on the protection motivation theory, the Self-Efficacy Scale, Positivity Scale, Preventive Behaviors Scale, and Satisfaction of Health Services Scale were adopted in the survey. Cronbach's α coefficient was used to evaluate scale reliability. A structural equation model was constructed for validity test and path analysis. Maximum likelihood method was used for parameter estimation, and bias-corrected percentile Bootstrap method was used to verify mediating effect. Results A total of 187 resident aliens were approached and 180 of them returned valid questionnaires. The Cronbach's α coefficients of the Self-Efficacy Scale, Positivity Scale, and Preventive Behaviors Scale were 0.904, 0.784, and 0.821, respectively. The M (P₂₅, P₇₅) scores of self-efficacy, positivity, preventive behaviors, and satisfaction of health services were 32 (27, 35), 29 (25, 30), 17 (14, 20), and 4 (3, 5), respectively. Statistically significant differences in the scores of preventive behaviors were identified among the participants by religious belief, geographical location, and economy (P<0.05). The results of path analysis showed that satisfaction of health services, positivity, and self-efficacy had direct positive effects on preventive behaviors (P<0.05), and positivity and self-efficacy played multiple mediation roles in the relationship between satisfaction of health services and preventive behaviors. The results of mediating effect test showed that the indirect effects of the three identified paths mediated by positivity and self-efficacy were statistically significant, and the total size of indirect effect was 0.316 (95%CI: 0.180, 0.466) that accounted for 61.2% of the total effect size. The strongest mediating path was satisfaction of health services→positivity→preventive behaviors, with an indirect effect size of 0.167 (95%CI: 0.046, 0.335) that accounted for 32.4% of the total effect size. Conclusion Future studies and policy formulation on preventive behaviors of foreigners in China should focus on the social demographic factors such as geographical location of home country, religious belief, and cultural customs. At the same time, the study of path relationship of preventive behaviors should embrace environmental factors, emotional factors, and cognitive factors.

Background The development of railways has a long history, but there is limited research on the health of railway workers at home and abroad. China's high-speed railway development has attracted worldwide attention in recent years, and it is of great significance to study how to promote the health of this occupational population to ensure the safety of railway transportation. Objective To identify development trends and hotspots in the field of railway workers' health at home and abroad. Methods The research literature related to the health of railroad workers dated from January 1, 1973 to December 31, 2022 was searched using the China Knowledge Network Infrastructure (CNKI) and Web of Science Core Collection (WoS) databases. After screening and cleaning, the included literature was subjected to bibliometric analysis by applying CiteSpace 6.1R6 software to visualize and analyze literature co-citation, keyword emergence, and keyword timeline graphs, and by VOSviewer 1.6.19 to visualize and analyze country/region collaboration, keyword co-occurrence, and keyword clustering. Results During the period from 1973 until 2022, a total of 273 Chinese literature and 165 English literature were found to report studies related to the health of railway workers. The Chinese literature began to grow rapidly in 2009 and peaked in 2015, and the number of English literature published in a relatively flat state over the studied period. The country with the most papers indexed by Science Citation Index (SCI) was the United States (58 papers), which also presented the richest international collaborations. The document with the highest domestic citation frequency was published in the Chinese Journal of Mental Health in 1994, and the document with the highest SCI citation frequency was published in the American Journal of Epidemiology in 1994. The keyword co-occurrence analysis showed that the included Chinese literature mainly focused on health checkups, health management, hypertension, mental health, and chronic diseases and their prevalence; the included English literature focused on mortality, lung cancer, epidemiology, and diesel engine exhaust and its exposure. The analysis of emergent words showed that health management, frontline workers, and occupational stress were the topics of interest in Chinese literature in the last five years, while occupational stress, diesel exhaust emissions, and noise exposure were the topics of interest in English literature in the last ten years. The results of the timeline graph analysis suggested that the recent research directions in Chinese literature were health intervention, humanistic care, staff canteens, etc. There were few English-language articles related to this area after 2010. Conclusion The research hotspots of railroad practitioners' health will keep changing with the development of high-speed railways in countries around the world. The outstanding rise of Chinese literature issued in the last decade has been in striking contrast to the slow progress and decreasing of English literature. The Chinese literature has gradually expanded the hotspots from chronic diseases to health management, occupational stress, and sleep disorders.

Background Immigrant health is an key node in achieving the goal of universal health coverage proposed by 2030 Agenda for Sustainable Development. The shock of severe public health emergency may exacerbate the original health-related contradictions of this group and bring more negative health effects. Objective To identify academic research hotspots and directions of immigrant health, and to examine trends in research hotspots before and after the public health emergency, so as to provide references to study immigrant health and response to public health emergency in the future. Methods Articles (document type) included in Web of Science core collection from 2017-01-01 to 2022-12-31 were retrieved. Microsoft Excel 2019 was used for descriptive analysis of included papers. VOSviewer 1.6.19 and CiteSpace 6.1.R6 were combined to draw cooperation maps of authors, institutions, and countries/areas to understand their cooperation and communication, and to draw keywords co-occurrence map, keywords clusters map, and keywords burst map to examine the hotspots and trends of immigrant health research before and after public health emergency. Results A total of 5997 papers pertaining to immigrant health from 2017 to 2022 were included, and the number of publications every year were overall on the rise generating a group of productive core authors. Institutions from the United States, Canada, and Northern Europe not only tightly cooperated within their countries/areas, but also cooperated frequently among countries/areas, forming an international cooperation network with the United States as its core. The keywords co-occurrence map showed that from 2017 to 2022, the research hotspots of immigrant health mainly focused on target groups of women, children, and refugees, and the study topics of mental health, acculturation, and care. The results of cluster analysis and further extraction found that the research topics in this field were divided into five categories: maternal and child health care, acculturation and mental health, health services, health equity, and chronic disease. The keywords burst map revealed that the research hotspots shifted from ethnic group, risk behavior, and sexes to COVID-19, health equity, social isolation, and victimization under the impact of public health emergency. Conclusion The cooperation and communication among study teams, institutions, and countries/areas have promoted the development of immigrant health study. Public health emergency has exacerbated the existing vulnerability of immigrants, and the topics related to health equity and social isolation of immigrants have raised attention becoming the research forefront. It is suggested that under the impact of public health emergency, corresponding public health policies are needed to mitigate health inequities and social support is also required for immigrants to ensure their physical and mental health.

Background As traditional chemical and physical hazards as well as associated adverse health outcomes in workplace were wildly controlled in the past half century, the prevalence and disease burden of low back pain (LBP) have drawn more and more attention and become one of the important public health problems in the world. Objective To analyze the health loss and attributable disease burden of ergonomic risk factors for LBP in two major categories of occupations in China, aiming to provide evidence for formulating effective prevention and control policies of LBP in the workplace. Methods Based on the methodological framework of the Global Burden of Disease Study (GBD), a meta-analysis was firstly applied to summarize relevant literature results and estimate the prevalence of LBP in two occupational groups (including technicians and associate professionals and machine operators and assemblers) by different age groups in China. Then important epidemiologic parameters (including disability weight, remission rate, and incidence) from GBD 2019 were used to estimate mean duration of disease and age at onset using DisMod II software, and to calculate health loss indexes in the selected occupational groups in China in 2013, such as years lived with disability (YLD) and disability-adjusted life year (DALY) of LBP and its attributable fractions by ergonomic risk factors, which were compared to the outcome of GBD 2013. Results After the adjustment by DisMod II, the prevalence rate of LBP was 13.00% in technicians and associate professionals (11.25% for males and 14.84% for females) and 14.80% in machine operators and assemblers (13.56% for males and 16.10% for females) in 2013, which increased with age. The DALY rate of LBP was 8.02‰ in technicians and associate professionals (7.68‰ for males and 8.33‰ for females) and 10.34‰ in machine operators and assemblers (10.30‰ for males and 10.44‰ for females), which also showed an overall increasing trend with age. In 2013, the population attributable fraction (PAF) of ergonomic risk factors to LBP was 11.42% in technicians and associate professionals and 29.17% in machine operators and assemblers. The DALY of LBP attributable to ergonomics risk factors was 4498 person-years (2108 person-years for males), with the highest DALY in the 45-49 year group (951 person-years), and the attributable DALY rate was 0.92‰ in technicians and associate professionals. The DALY of LBP attributable to ergonomics risk factors was 48529 person-years (33046 person-years for males), with the highest DALY in the 40-44 year group (10852 person-years), and the attributable DALY rate was 3.02‰ in machine operators and assemblers. Regarding LBP-associated DALY rate, in the 20 years of age and above group, both occupational groups (technicians and associate professionals: 8.06‰, machine operators and assemblers: 10.66‰) showed higher values than the general population (3.55‰). In the 20 years of age and above group, the DALY rates attributable to ergonomic risk factors with the order from high to low were machine operators and assemblers (3.11‰), general population (1.10‰) and technicians and associate professionals (0.92‰). Conclusion The LBP-associated disease burden is heavier in the two Chinese occupational groups than in general population. Reducing the disease burden of LBP by interventions targeting ergonomic risk factors in machine operators and assemblers is more effective than that in technicians and associate professionals as the results of attributable burden of disease suggest.

Background Nursing staff are often exposed to a variety of occupational risk factors in the working environment, such as long working hours and heavy workload, which associated with adverse mental health outcomes. And these factors may not be randomly distributed across different levels. Objective To explore mental health risk factors of nursing staff by multilevel analysis. Methods A cross-sectional survey of nursing staff in Shanghai Municipality, Zhejiang Province, Guangxi Zhuang Autonomous Region, and Xinjiang Uygur Autonomous Region was conducted through convenience sampling from 2018 to 2021. Data were collected by self-report questionnaires. The mental component summaries of 12-Iitem Short Form Health Survey were used to evaluate the mental health status of nursing staff, and related factors were collected atindividual level, including gender, body mass index (BMI), smoking status, drinking status, working years, pain intensity of musculoskeletal disorders, and working hours per week, and at regional level, including gross domestic product (GDP) level of each province. A two-level model was established by incorporating both individual and regional factors, and deviance was used to test the goodness of fit of the model. A traditional generalized linear model was also established, and then compared with the multilevel model. Results A total of 567 nurses participated in this study, and the valid rate of questionnaire was 80.08%. The results of the multilevel model showed that the regional factor contributed 12.1% to the mental component summaries. As to the regional factor, GDP was negatively correlated with mental health of nursing staff, the adjusted OR (AOR) was −0.53 (95%CI: −0.66-−0.28). Among the factors at individual level, the mental component summaries of females were lower than those of males (AOR=−3.25, 95%CI: −4.73-−0.35); the longer the working years, the higher the mental health score (AOR=0.11, 95%CI: 0.06-0.20); working hours per week (AOR=−0.10, 95%CI: −0.14-−0.03) and pain intensity of musculoskeletal disorders (AOR=−0.05, 95%CI: −0.06-−0.03) were negatively correlated with mental component summaries. The results of the generalized linear model included the same factors as the multilevel model, but the 95%CIs of AOR of the factors in the multilevel model were narrower, and the deviation value of the multilevel model was the smallest, indicating that the goodness of fit of the multilevel model was better than that of the traditional linear model. Conclusion The mental health of nursing staff is not only affected by individual level factors, but also affected by regional level factors. It suggests that combining different levels of intervention measures can upscale the effect of improving mental health in nursing staff.

Radar uses electromagnetic waves to detect， track and locate objects at certain distances， which is widely used in military， meteorological， navigation and other fields. Radar emits electromagnetic waves outward and produces non-ionizing radiation， which may be considered as a physical occupational hazard. Epidemiological surveys found that long-term exposure to radar is associated with various adverse health effects， which may be correlated to transmitted power and frequency of radar， location of radar antenna， position of workers， and shielding effectiveness of cabins where work station is located. Based on radar frequency and electromagnetic radiation intensity， this study summarizes the health effects of radar on occupational population exposed to radar.

Background In recent years, road traffic injury (RTI) has become a serious public health problem in China, and the factors affecting deaths caused by RTI are also complicated. Objective This study is designed to identify factors of RTI fatality risk and establish a road user fatality risk prediction model. Methods The data of traffic accident casualties in Pudong New Area of Shanghai from 2010 to 2016 were collected retrospectively, and the related impact factors of RTI were collected. Logistic regression was used to screen the selected factors of RTI fatality risk. A nomogram of RTI fatality risk was established, the consistency and accuracy of the model was evaluated by C-index and bootstrap internal verification, and a sensitivity analysis was also conducted. Results A total of 3521 casualties in traffic accidents were included in the study. The logistic regression results showed that age of victims, medical rescue distance, road type, transport means, injured body part, time of accident, and weekday/weekend affected RTI death risk (P<0.05). The nomogram model for RTI death risk showed that the most affecting factors were injured body part (especially head and neck injury), followed by age, transportation means, medical rescue distance, road type, time of accident, and weekday/weekend. The C-index of the model was 0.790, indicating high prediction accuracy and good fitness. The nomogram model for RTI death risk of head and neck injury showed that the score scales of all included factors expanded, the most prominent (most affecting) one was age; the RTI fatality risk of different road types changed, where urban road became the most dangerous road type; in addition, walking was the transportation means with the greatest risk of RTI fatality from head and neck injury. The results of the sensitivity analysis on accidents with varied casualties confirmed the robustness of the model. Conclusion The road user fatality risk of RTI is affected by many factors. As a simple tool to predict fatality risk of RTI, the nomogram based on logistic regression has certain reference significance for road traffic safety.