Objective:To investigate the fit of dust-exposed workers wearing KN95 masks in a city of Guangdong Province, and to discuss the intervention effect of nose pads and elastic adjustment clasps on the fit of KN95 masks.Methods:In January 2024, 145 dust-exposed workers from a stone processing enterprise in a city of Guangdong Province were selected as study subjects by convenience sampling, and 4 types of KN95 masks commonly used by dust-exposed workers were selected as test masks. The head and face dimensions of the study subjects were measured using a right-angle gauge and a curved-angle gauge, and the fit factor (FF) of the KN95 masks was tested using the quantitative fit test for respiratory protective equipment, and the intervention of adding nose pads or elastic adjustment clasps was given to those who failed the first fit test. The paired t-test was used to compare the changes of workers' FF before and after the intervention. Results:The coverage rate of the study population in the facial subsection of the Chinese Han population was 71.0% (103/145). Before intervention, the overall passing rate of the fit test of 4 types of KN95 masks was 16.6% (24/145), and the passing rate of 4 types of masks had statistical significance ( χ2=19.73, P<0.001). After intervention, the overall passing rate of the fit test of masks was 33.9% (41/121), and the geometric mean of the total FF after intervention increased from 15.9 to 62.7 ( t=-13.53, P<0.001), among which 88.4% (107/121) workers' FF improved after intervention, and 11.6% (14/121) of workers had reduced FF. Conclusion:Dust-exposed workers in a city of Guangdong Province have a low coverage rate of facial subsection among Chinese Han population, and the passing rate of KN95 mask fit test is low. Interventions using additional nose pads or elastic adjustment clasps can partially improve the fit of the mask, and it is still necessary to continue to explore interventions to improve the fit of mask wearers.

Objective:To understand the current status of the actual protective effect of respiratory protective equipment (RPE) for workers exposed to trichloroethylene (TCE), and to explore the factors affecting the actual protective effect.Methods:From July to December 2023, a total of 75 workers occupationally exposed to TCE from 21 hardware and electronics manufacturing facilities in a province were selected as research objects by convenient sampling method. Workplace protection factor (WPF) was used as an index to evaluate the actual protective effect of workers' RPE. The concentration of TCE inside and outside the RPE was detected to calculate WPE, and the temperature, humidity and wind speed near the working place were measured, as well as the forced vital capacity, respiratory rate, heart rate and other indicators of the worker were measured. The log-transformed WPF value (lgWPF) followed a normal distribution. One-sample t-test was used to compare the difference between the mean lgWPF and the log value of the assigned protection factor (APF) of the half mask (lgAPF=1). Multiple linear regression model was used to investigate the influencing factors of lgWPF. Results:The lgWPF of 75 TCE-exposed workers ranged from 0.40 to 1.32 (0.84±0.22). The mean of lgWPF was lower than that of lgAPF, and the difference was statistically significant ( t=-6.37, P<0.001). After adjusting for confounding factors, the results of multiple linear regression showed that humidity, forced vital capacity and respiratory rate were negatively correlated with lgWPF ( β=-0.008, -0.079, -0.021, P<0.05) . Conclusion:The actual protective efficacy of RPE among workers exposed to TCE is suboptimal. High humidity, elevated forced vital capacity, and increased respiratory rate may be contributing factors to the diminished protective performance of RPE.

Objective:To understand the occupational injury situation of front-line workers in metallurgical and shipbuilding and repairing industry, and explore the risk factors of occupational injury.Methods:From September 2023 to March 2024, using cluster sampling method, front-line workers from 2 metallurgical enterprises in Shaoguan and Jinan City and 2 shipbuilding and repairing enterprises in Jiangmen and Shenzhen City were selected as the investigation objects. 6248 questionnaires were distributed and collected, and 6178 were effective questionnaires, with a effective recovery rate of 98.88%. The basic information, living habits, working system, protection and occupational injury of workers were investigated, and the data of occupational injury in factories was collected. The types, jobs and main causes of occupational injuries in different industries were analyzed, and the influencing factors of occupational injuries were analyzed by univariate and multi-factor logistic regression.Results:The incidence of occupational injury was 3.13% (128/4086) in metallurgical industry and 4.02% (84/2092) in shipbuilding and repairing industry. The top three occupational injuries in the metallurgical industry were furnace worker (17.19%, 22/128), steel rolling worker (14.84%, 19/128), maintenance worker (10.16%, 13/128), and the top three injury types were mechanical injury (24.22%, 31/128), height fall (20.31%, 26/128) and object strikes (17.97%, 23/128). The top three occupational injuries in shipbuilding and repairing industry were welder (20.24%, 17/84), riveter (9.52%, 8/84) and crane (8.33%, 7/84). The top three injury types were hit by objects (34.52%, 29/84), hit by falling objects (22.62%, 19/84), and lifting injury (20.24%, 17/84). The injuries of workers in metallurgical industry and shipbuilding and repairing industry were mainly fractures, accounting for 32.03% (41/128) and 60.71% (51/84), respectively. The incidence of occupational injury was higher in males, with sleep disorder, high temperature exposure and chemical toxicity exposure ( P<0.05). There were significant differences in age, smoking degree, working age and emotional state between workers with occupational injury and those without occupational injury ( P<0.05). Multivariate analysis showed that male, age above 50 years old, moderate smoking, working years of 5-9 years, mild anxiety, poor health status and high temperature exposure were risk factors for occupational injury ( OR=25.57, 3.72, 14.27, 2.09, 1.50, 4.36, 0.66, P<0.05) . Conclusion:The incidence of occupational injury is higher in shipbuilding and repairing industry, and fracture is the main type of occupational injury. The occurrence of occupational injury is affected by gender, age, smoking, working age, emotional state, health status and high temperature exposure.

Objective:To evaluate the current situation of the protective effect of hearing protection device (HPD) worn by manufacturing workers and discuss their possible influencing factors.Methods:A total of 3634 noisy workers were surveyed and tested. The study conducted surveys of workers on the use of HPD. The 3M TM E-A-R Fit TM binaural verification system was used to measure the personal attenuation device (PAR) of workers wearing HPD. Results:The M ( Q1, Q3) of baseline PAR obtained by 3634 workers was 12 (2, 19) dB. There was a statistically significant difference in baseline PAR among the three types of HPDs ( H=336.39, P<0.01) . After pairwise comparison, it was found that the baseline PAR of workers wearing foam earplugs and earmuffs was higher than that of pre-molded earplugs ( P<0.01) . There were differences in baseline PAR among workers in different industries ( Z=359.73, P<0.01) . Education level, age of using HPD, types of HPDs, noise exposure intensity, with or without knowledge of correct methods, and comfort evaluation were the main factors affecting baseline PAR ( P<0.05) . There were 1536 workers (43.4%) failed the baseline PAR test. After the intervention, the median PAR increased significantly from 1 (0, 6) dB (baseline) to 18 (14, 22) dB (after the intervention) ( P<0.01) . The follow-up test found that the follow-up PAR of 328 workers was higher than the baseline PAR of the initial test, and the follow-up PAR was higher than the post-intervention PAR of the initial test ( P<0.01) . Conclusion:Under the conditions of this study, the protective effect of HPD was affected by factors such as incorrect understanding of wearing methods, exposure to high-intensity noise, low education level, a short period of time of HPD use and low comfort of hearing protectors. The protective effect could be improved through training, optimizing the wearing of hearing protector models, and follow-up interventions. Enterprises should use suitability verification to ensure the correct selection and wearing of noisy workers.

BackgroundModified electroconvulsive therapy （MECT） is a common front-line strategy widely used in psychiatric practice， and the optimal first stimulus dosage in MECT is usually estimated clinically based on the factors influencing the patient's initial seizure threshold （IST）. However， previous studies on the influencing factors of IST have mostly suffered from limitations such as small sample sizes and single-dimensional research perspectives. ObjectiveTo explore the factors influencing IST in MECT for patients with mental disorders， so as to provide references for stimulus dosing strategies in MECT for the patients. MethodsA retrospective study was used to include 1 446 inpatients fulfilling the diagnostic criteria for any specific mental disorder listed in the ICD-10 and receiving MECT at Shandong Daizhuang Hospital from January 1， 2021 to August 1， 2023. Their general and clinical data were collected， including IST， psychiatric diagnostic categories， gender， ethnicity， age， body weight， body mass index （BMI）， course of disease， family history of psychiatric disorders， first episode status， use of antiepileptic drugs the day before treatment， use of benzodiazepines the day before treatment， and previous MECT treatment history. Pearson correlation analysis was utilized to test the correlation of IST with age， height， body weight， BMI， and course of disease， and stepwise multivariate linear regression analysis was performed to identify the factors affecting IST. ResultsIST yielded statistical difference among patients in terms of gender， first episode status， use of antiepileptic drugs the day before treatment， and use of benzodiazepines the day before treatment （t=2.256， -3.059， -2.136， -3.006， P<0.05 or 0.01）. IST in patients of different ages and psychiatric diagnostic categories also demonstrated statistical difference （F=913.120， 6.212， P<0.01）. Within young population， IST varied significantly based on the psychiatric diagnostic categories （F=2.986， P<0.05）. Correlation analysis indicated that IST was positively correlated with age， body weight， BMI and course of disease （r=0.886， 0.055， 0.184， 0.456， P<0.05 or 0.01）， and negatively correlated with height （r=-0.183， P<0.01）. Stepwise multivariate linear regression analysis revealed that age， gender， and body weight were influencing factors of IST （β=0.888， -0.049， -0.035， P<0.01）. ConclusionsAge， gender and body weight may be factors influencing IST in MECT for patients with mental disorders. ［Funded by Key R&D Plan Projects of Jining City in 2024 (number, 2024YXNS202）］

Objective:To investigate the fit of dust-exposed workers wearing KN95 masks in a city of Guangdong Province, and to discuss the intervention effect of nose pads and elastic adjustment clasps on the fit of KN95 masks.Methods:In January 2024, 145 dust-exposed workers from a stone processing enterprise in a city of Guangdong Province were selected as study subjects by convenience sampling, and 4 types of KN95 masks commonly used by dust-exposed workers were selected as test masks. The head and face dimensions of the study subjects were measured using a right-angle gauge and a curved-angle gauge, and the fit factor (FF) of the KN95 masks was tested using the quantitative fit test for respiratory protective equipment, and the intervention of adding nose pads or elastic adjustment clasps was given to those who failed the first fit test. The paired t-test was used to compare the changes of workers' FF before and after the intervention. Results:The coverage rate of the study population in the facial subsection of the Chinese Han population was 71.0% (103/145). Before intervention, the overall passing rate of the fit test of 4 types of KN95 masks was 16.6% (24/145), and the passing rate of 4 types of masks had statistical significance ( χ2=19.73, P<0.001). After intervention, the overall passing rate of the fit test of masks was 33.9% (41/121), and the geometric mean of the total FF after intervention increased from 15.9 to 62.7 ( t=-13.53, P<0.001), among which 88.4% (107/121) workers' FF improved after intervention, and 11.6% (14/121) of workers had reduced FF. Conclusion:Dust-exposed workers in a city of Guangdong Province have a low coverage rate of facial subsection among Chinese Han population, and the passing rate of KN95 mask fit test is low. Interventions using additional nose pads or elastic adjustment clasps can partially improve the fit of the mask, and it is still necessary to continue to explore interventions to improve the fit of mask wearers.

Objective:To understand the current status of the actual protective effect of respiratory protective equipment (RPE) for workers exposed to trichloroethylene (TCE), and to explore the factors affecting the actual protective effect.Methods:From July to December 2023, a total of 75 workers occupationally exposed to TCE from 21 hardware and electronics manufacturing facilities in a province were selected as research objects by convenient sampling method. Workplace protection factor (WPF) was used as an index to evaluate the actual protective effect of workers' RPE. The concentration of TCE inside and outside the RPE was detected to calculate WPE, and the temperature, humidity and wind speed near the working place were measured, as well as the forced vital capacity, respiratory rate, heart rate and other indicators of the worker were measured. The log-transformed WPF value (lgWPF) followed a normal distribution. One-sample t-test was used to compare the difference between the mean lgWPF and the log value of the assigned protection factor (APF) of the half mask (lgAPF=1). Multiple linear regression model was used to investigate the influencing factors of lgWPF. Results:The lgWPF of 75 TCE-exposed workers ranged from 0.40 to 1.32 (0.84±0.22). The mean of lgWPF was lower than that of lgAPF, and the difference was statistically significant ( t=-6.37, P<0.001). After adjusting for confounding factors, the results of multiple linear regression showed that humidity, forced vital capacity and respiratory rate were negatively correlated with lgWPF ( β=-0.008, -0.079, -0.021, P<0.05) . Conclusion:The actual protective efficacy of RPE among workers exposed to TCE is suboptimal. High humidity, elevated forced vital capacity, and increased respiratory rate may be contributing factors to the diminished protective performance of RPE.

Objective:To understand the occupational injury situation of front-line workers in metallurgical and shipbuilding and repairing industry, and explore the risk factors of occupational injury.Methods:From September 2023 to March 2024, using cluster sampling method, front-line workers from 2 metallurgical enterprises in Shaoguan and Jinan City and 2 shipbuilding and repairing enterprises in Jiangmen and Shenzhen City were selected as the investigation objects. 6248 questionnaires were distributed and collected, and 6178 were effective questionnaires, with a effective recovery rate of 98.88%. The basic information, living habits, working system, protection and occupational injury of workers were investigated, and the data of occupational injury in factories was collected. The types, jobs and main causes of occupational injuries in different industries were analyzed, and the influencing factors of occupational injuries were analyzed by univariate and multi-factor logistic regression.Results:The incidence of occupational injury was 3.13% (128/4086) in metallurgical industry and 4.02% (84/2092) in shipbuilding and repairing industry. The top three occupational injuries in the metallurgical industry were furnace worker (17.19%, 22/128), steel rolling worker (14.84%, 19/128), maintenance worker (10.16%, 13/128), and the top three injury types were mechanical injury (24.22%, 31/128), height fall (20.31%, 26/128) and object strikes (17.97%, 23/128). The top three occupational injuries in shipbuilding and repairing industry were welder (20.24%, 17/84), riveter (9.52%, 8/84) and crane (8.33%, 7/84). The top three injury types were hit by objects (34.52%, 29/84), hit by falling objects (22.62%, 19/84), and lifting injury (20.24%, 17/84). The injuries of workers in metallurgical industry and shipbuilding and repairing industry were mainly fractures, accounting for 32.03% (41/128) and 60.71% (51/84), respectively. The incidence of occupational injury was higher in males, with sleep disorder, high temperature exposure and chemical toxicity exposure ( P<0.05). There were significant differences in age, smoking degree, working age and emotional state between workers with occupational injury and those without occupational injury ( P<0.05). Multivariate analysis showed that male, age above 50 years old, moderate smoking, working years of 5-9 years, mild anxiety, poor health status and high temperature exposure were risk factors for occupational injury ( OR=25.57, 3.72, 14.27, 2.09, 1.50, 4.36, 0.66, P<0.05) . Conclusion:The incidence of occupational injury is higher in shipbuilding and repairing industry, and fracture is the main type of occupational injury. The occurrence of occupational injury is affected by gender, age, smoking, working age, emotional state, health status and high temperature exposure.

Objective:To evaluate the current situation of the protective effect of hearing protection device (HPD) worn by manufacturing workers and discuss their possible influencing factors.Methods:A total of 3634 noisy workers were surveyed and tested. The study conducted surveys of workers on the use of HPD. The 3M TM E-A-R Fit TM binaural verification system was used to measure the personal attenuation device (PAR) of workers wearing HPD. Results:The M ( Q1, Q3) of baseline PAR obtained by 3634 workers was 12 (2, 19) dB. There was a statistically significant difference in baseline PAR among the three types of HPDs ( H=336.39, P<0.01) . After pairwise comparison, it was found that the baseline PAR of workers wearing foam earplugs and earmuffs was higher than that of pre-molded earplugs ( P<0.01) . There were differences in baseline PAR among workers in different industries ( Z=359.73, P<0.01) . Education level, age of using HPD, types of HPDs, noise exposure intensity, with or without knowledge of correct methods, and comfort evaluation were the main factors affecting baseline PAR ( P<0.05) . There were 1536 workers (43.4%) failed the baseline PAR test. After the intervention, the median PAR increased significantly from 1 (0, 6) dB (baseline) to 18 (14, 22) dB (after the intervention) ( P<0.01) . The follow-up test found that the follow-up PAR of 328 workers was higher than the baseline PAR of the initial test, and the follow-up PAR was higher than the post-intervention PAR of the initial test ( P<0.01) . Conclusion:Under the conditions of this study, the protective effect of HPD was affected by factors such as incorrect understanding of wearing methods, exposure to high-intensity noise, low education level, a short period of time of HPD use and low comfort of hearing protectors. The protective effect could be improved through training, optimizing the wearing of hearing protector models, and follow-up interventions. Enterprises should use suitability verification to ensure the correct selection and wearing of noisy workers.

Objective:To assess the efficacy of silicone earplugs in protecting workers exposed to noise in a typical manufacturing environment, and to provide training interventions for workers who do not achieve the anticipated noise reduction levels, as well as examining the spectral characteristics of earplug attenuation.Methods:From June to August 2022, a total of 294 noise-exposed workers in two manufacturing enterprises equipped with the same type of earplug were studied by cluster sampling method, by conducting questionnaire surveys, collecting data, fitting tests, and providing trainings, the current noise exposure levels of workers in the industry as well as the perception about the earplug were understood. Additionally, the attenuation before and after intervention in workplace were measured, the spectral characteristics of noise reduction were were described and compared.Results:The percentage of workers with Personal Attenuation Rating (PAR) of 0 is 32.7% (96/294), and the baseline pass rates are all below 60%. There were no significant differences in pass rates based on gender, age, noise exposure, education level, or cognition of earplug effectiveness. After adjusting the way that earplugs are worn or changing the type of earplugs, all workers were able to meet their noise reduction requirements. The median PAR improvement for both companies is above 10 dB. The noise attenuation of the earplug vary with frequency, with lower attenuation at 4 000 Hz and higher attenuation at 8 000 Hz, showing some deviation from the nominal values.Conclusion:The difference between the actual sound attenuation value of earplugs and the nominal value is related to the noise frequency. When using silicone earplugs, attention should be paid to the spectral composition of the noise in the workplace.