Background Hypertension is one of the chronic diseases with the highest prevalence in China, and a history of hypertension may potentially exacerbate hearing loss. Investigating the association between long-term blood pressure trends and hearing thresholds could contribute to hearing protection efforts for occupationally noise-exposed populations. Objective By investigating hearing thresholds and blood pressure levels among occupationally noise-exposed workers in an urban rail transit enterprise, and conducting a comprehensive analysis of the association between long-term blood pressure changes and hearing thresholds, to provide data references for health management strategies targeting occupationally noise-exposed workers. Methods Workers exposed to occupational noise at a rail transit enterprise were enrolled as study subjects and underwent pure-tone audiometry. Group-based trajectory modeling was employed to identify blood pressure trajectories. Categorical data were compared using chi-square tests, while normally distributed continuous variables were analyzed via t-tests and analysis of variance (ANOVA). Generalized linear mixed models (GLMMs) were subsequently applied toexamine associations between these trajectory groups and high-frequency hearing thresholds. Results Among 2 002 occupationally noise-exposed workers, the median (P₂₅, P₇₅) age was 32 (28, 35) years, with a median (P₂₅, P₇₅) working tenure of 7 (3, 10) years. In 2019, the positive hypertension rate was 9.04%, with a mean systolic blood pressure (SBP) of (122.97±11.60) mmHg and a mean diastolic blood pressure (DBP) of (76.37±9.02) mmHg. The hearing loss prevalence was 10.1%, showing bilateral high-frequency average hearing thresholds of (17.18±8.71) dB and speech-frequency average thresholds of (13.79±3.46) dB. Three distinct trajectory groups were identified for both SBP and DBP. Compared with other trajectory groups, the high-stable DBP group exhibited significantly higher hearing loss prevalence (χ²=6.34, P=0.042) and elevated high-frequency hearing thresholds (all Ps<0.05). Specifically, within the 30-39 age subgroup, the moderate-stable DBP group demonstrated 1.96 dB lower high-frequency thresholds than the high-stable group [β(95%CI): −1.96 (−3.61, −0.32), P=0.020]. Conclusion Among occupationally noise-exposed workers in a municipal rail transit enterprise, DBP trajectories demonstrated a positive association with high-frequency hearing thresholds. Notably, in young and middle-aged occupationally noise-exposed populations, DBP may exert a more critical influence than SBP on the progression of hearing loss.

ObjectiveTo establish a managing mode for illegal and irregular acts of occupational medical examination (OME) institutions to the requirements of the new situation. Methods The OME institutions from the “Guangdong Province Key Occupational Disease Monitoring and Management Platform” were selected as the study subjects using the judgment sampling method. The clues of suspected illegal and irregular acts of OME institutions were found and submitted to the local health commission for investigation and managed according to the case information monitoring and on-site quality assessment. The OME institutions found to have illegal and irregular acts were filed and investigated according to the national law after investigation and verification. A “follow-up inspection” was conducted on five OME institutions for closed loop management. Results A total of 12 OME institutions were found to have suspected illegal and irregular acts, including seven institutions that did not meet the filing requirements for effective personnel, five institutions that conducted projects beyond the scope without filing to the provincial health authorities within 15 work days from the start of the project, and two institutions that failed to fulfill the obligation of informing and reporting to the health authorities, employers, and workers as required. After submitting relevant clues and evidence to the local health commission for investigation and management, seven institutions were not given penalty, and five institutions were given administrative penalties including two institutions were fined and warned, and three institutions were warned. No illegal or irregular acts were found in the five institutions inspected during the “follow-up inspection”. Conclusion It is beneficial to explore the managing mode of “clue discovery, clue submission, investigation and disposal, follow-up inspection” for OME institutions suspected of illegal and irregular acts, which helps urge OME institutions to work in accordance with laws and regulations and effectively protect the legitimate rights and interests of workers' occupational health.

Objective To analyze the problems found in the on-site quality assessment of occupational medical examination (OME) institutions in Guangdong Province. Methods A total of 150 OME institutions were selected as the research subjects from Guangdong Province in 2023 using a random number table method. The on-site quality assessment was conducted by listening to reports, meeting discussion, on-site inspection, data review and human-machine assessment. The relevant assessment results were analyzed. Results Occupational disease prevention and treatment institutes (institutes, centers) and disease control and prevention centers (hereinafter referred to as "occupational prevention institutions"), public hospitals, and private institutions accounted for 8.7%, 51.3%, and 40.0% respectively. The top three categories of registered inspections were physical factors, chemical factors and dust, accounted for 98.0%, 96.7% and 96.0%, respectively, among the 150 OME institutions. A total of 1 063 rectification items were identified, and the average number of rectification items identified per occupational prevention institutions, public hospitals and private institutions was four, six and nine, respectively. The rectification rates of the four modules of quality assessment from high to low were OME work quality control, quality management system, organizational structure, and OME information reporting, accounted for 53.2%, 23.3%, 13.7% and 9.7%, respectively. The coincidence rate from high to low of occupational reporting of noise-exposure, dust-exposure, and other hazard-exposure was 92.5%, 91.1%, and 93.4%, respectively. The on-site failure rate of quality control director, technical director, chief physician, pneumoconiosis film reader, audiometry reader and pulmonary function examination operator accounted for 15.3%, 12.7%, 8.0%, 6.7%, 6.0% and 2.7%, respectively. Institutions capable of conducting registered and partially registered OME accounted for 90.7% and 6.0%, respectively. The five institutions that were unable to conduct registered OME were private institutions. A total of five private institutions were found to be suspected of illegal and irregular activities. Conclusion The problems of OME in the on-site quality assessment of OME institutions in Guangdong Province were mainly quality control. Private institutions had more prominent problems in various aspects. It is necessary to strengthen the training of key personnel such as technical directors, quality control directors, and chief physicians.

As the management system of Occupational Medical Examination (OME) institutions is moving to a record-filing model, the traditional management approach might not fulfill the current policy requirements. There is a pressing need for development of high-quality occupational health management system. In this context, the Guangdong Provincial Occupational Health Examination Quality Control Center (hereinafter referred to as the "Provincial Quality Control Center") pioneered the integration of the Performance Excellence Model (PEM) framework into the macro-quality management of OME institutions in Guangdong Province. In light of the current research gaps in the field of macro-quality management for OME institutions, the Provincial Quality Control Center, based on the core principles and standards of PEM, has closely aligned with the professional characteristics of occupational health examinations. The established macro-quality management innovation in OME institutions in Guangdong Province consists of seven dimensions: strategic direction, leadership development, identification of key management subjects, data analysis and management, human resources allocation, process optimization, and the application of quality control outcomes. This system has provided a robust impetus for the ongoing improvement of quality control efforts. The initial implementation of PEM demonstrated notable improvements in macro-quality management for OME institutions. Moving forward, the Provincial Quality Control Center will continue to strengthen the development of key technical personnel, innovate training models, harness the advantages of big data technology, restate and upgrade the system continuously, and refine the macro-quality management mechanisms of OME institutions to ensure that the health rights and interests of workers and employers are effectively safeguarded and enhanced.

OBJECTIVE: To establish the occupational exposure limits for methyl t-butyl ether(MTBE) in the air of workplace in China. METHODS: According to the GBZ/T 210.1-2008 Guide for Establishing Occupational Health Standards--Part 1: Occupational Exposure Limits for Airborne Chemicals in the Workplace, we collected and analyzed data on physical and chemical properties, toxicology, occupational epidemiology and foreign occupational exposure limits related to MTBE by literature search. A total of 180 occupational workers exposed to MTBE were selected as exposure group, and 155 workers and administrative logistics personnel without exposure to MTBE were selected as the control group. Occupational hygiene investigation and occupational physical examination were carried out. We deduced the occupational exposure limits for MTBE in workplace air in China by combining literature data. RESULTS: The time-weighted average(TWA) of MTBE in the workplace air developed by the United States of America and Britain is 180.00 mg/m~3. The short-term exposure limit(STEL) of MTBE in the workplace air developed by Australia and New Zealand is 270.00 mg/m~3. The concentration of TWA(C_(TWA)) of MTBE in the exposure group was less than 0.08-4.90 mg/m~3. The concentration of short term exposure was less than 0.10-14.28 mg/m~3, and the C_(TWA) was less than 0.02-83.66 mg/m~3, in parts of workplaces. There was no statistically significant difference on the self-conscious discomfort and the abnormality in physical examination between these two groups(P>0.05). CONCLUSION: It's recommended that the permissible concentration-TWA of MTBE should be set at 180.00 mg/m~3, and the permissible concentration-STEL should be set at 270.00 mg/m~3 in China.

Objective: To investigate the characteristics of acoustic impedance test and its diagnostic role for occupational noise induced deafness, in order to provide an objective basis for the differential diagnosis of occupational noise induced deafness. Methods: A retrospective study was conducted to investigate the cases on the diagnosis of occupational noise-induced deafness in Guangdong province hospital for occupational disease prevention and treatment from January 2016 to January 2017. A total of 198 cases (396 ears) were divided into occupation disease group and non occupation disease group based on the diagnostic criteria of occupational noise deafness in 2014 edition, acoustic conductivity test results of two groups were compared including tympanograms types, external auditory canal volume, tympanic pressure, static compliance and slope. Results: In the occupational disease group, 204 ears were found to have 187 ears (91.67%) of type A, which were significantly higher than those in the non occupational disease group 143/192 (74.48%) , the difference was statistically significant (χ²=21.038, P<0.01). Detection of Ad or As type, occupation disease group in other type were 16/204 (7.84%) , 3/204 (1.47%) , were lower than Ad or As type of occupation disease group (15.63%) , other type (9.38%) , the differences were statistically significant[ (χ²=5.834, P<0.05) , (χ²=12.306, P<0.01) ]. Occupation disease group canal volume average (1.68±0.39) ml higher than that of non occupation disease group (1.57±0.47) ml, the difference was statistically significant (t=2.756, P<0.01) ; occupation disease group mean static compliance (1.06±0.82) ml higher than that of non occupation disease group (0.89±0.64) ml. The difference was statistically singificant (t=2.59, P<0.01) . Conclusion We observed that acoustic impedance test had obvious auxiliary function in the differential diagnosis of occupational noise induced deafness, More than 90% of the confirmed cases showed an A-form tympanograms, it is one of the objective examination methods which can be used in the differential diagnosis of pseudo deafness.

OBJECTIVE: To explore the application of the autoregressive integrated moving average model( ARIMA model)in predicting incidence of occupational noise-induced deafness( ONID). METHODS: The ARIMA model was established and validated based on the number of new onset ONID cases in Guangdong Province from 2006 to 2015. Then the ARIMA model was used to predict the trend of new onset ONID cases from 2016 to 2020. RESULTS: The number of new ONID cases in Guangdong Province from 2006 to 2015 showed an exponential growth trend. The optimal model fitted with the number of new onset ONID cases from 2006 to 2015 was the ARIMA( 2,2,2) model,which better match the number of new onset ONID cases from 2008 to 2015. According to the ARIMA( 2,2,2) model,the number of new onset ONID cases in Guangdong Province will continue to have a rapidly increasing trend from 2016 to 2020. CONCLUSION: The ARIMA model based on time series matches the time trend of ONID onset,and it can be used for the prediction of ONID incidence trend.

Objective: To investigate the value of DNA content in comet tail (TailDNA) in predicting the changes in peripheral blood cell counts in workers exposed to benzene. Methods: In 2011, cluster sampling was used to select 150 male workers exposed to benzene in a petrochemical factory. Cubital venous blood and urine samples were collected for routine blood rest, comet assay, and measurement of s-phenylmercapturic acid (SPMA) and urine creatinine. The population was divided into groups according to urinary SPMA or TailDNA, and routine blood test results within 3 years were collected to analyze the changes in blood cell counts. Results: The low-SPMA group had significantly higher white blood cell and neutrophilcounts in all years than the high-SPMA group (P<0.05) . The low-Tail DNA group had a significant increase in platelet count from 2012 to 2014 (P<0.05) , while the high-Tail DNA group had no significant change (P>0.05) . During the 4-year period, the high-TailDNA group had a significantly lower red blood cell count than the low-TailDNA group (P<0.05) . The high-TailDNA group showed a gradual reduction in white blood cell count over time (β=-0.113, P<0.05) , and the low-TailDNA group showed no trend of the reduction in white blood cell count (P>0.05) . Conclusion TailDNA can be used to predict the changes in blood cell counts in workers exposed to benzene.

Objective: Study of the results and the degree on occupational noise-induced deafness in-to the different high frequency hearing threshold weighted value, in order to provide theoretical basis for the re-vision of diagnostic criteria on occupational noise-induced deafness. Methods: A retrospective study was con-ducted to investigate the cases on the diagnosis of occupational noise-induced deafness in Guangdong province hospital for occupational disease prevention and treatment from January 2016 to January 2017. Based on the re-sults of the 3 hearing test for each test interval greater than 3 days in the hospital, the best threshold of each frequency was obtained, and based on the diagnostic criteria of occupational noise deafness in 2007 edition, Chi square test, t test and variance analysis were used to measure SPSS21.0 data, their differences are tested among the means of speech frequency and the high frequency weighted value into different age group, noise ex-posure group, and diagnostic classification between different dimensions. Results: 1. There were totally 168 cases in accordance with the study plan, male 154 cases, female 14 cases, the average age was 41.18 ±6.07 years old. 2. The diagnosis rate was increased into the weighted value of different high frequency than the mean value of pure speech frequency, the weighted 4 kHz frequency increased by 13.69% (χ²=9.880, P=0.002) , 6 kHz increased by 15.47% (χ²=9.985, P=0.002) and 4 kHz+6 kHz increased by15.47% (χ²=9.985, P=0.002) , the difference was statistically significant. The diagnostic rate of different high threshold had no obvious differ-ence between the genders. 3. The age groups were divided into less than or equal to 40years old group (A group) and 40-50 years old group (group B) , there were higher the diagnostic rate between high frequency weighted 4 kHz (A group χ²=3.380, P=0.050; B group χ²=4.054, P=0.032) , weighted 6 kHz (A group χ²=6.362, P=0.012; B group χ²=4.054, P=0.032) , high frequency weighted 4 kHz+6 kHz (A group χ²=6.362, P=0.012; B group χ²=4.054, P=0.032) than those of speech frequency average value in the same group on oc-cupational noise-induced deafness diagnosis rate, the difference was statistically significant. There was no sig-nificant difference between age groups (χ²=2.265, P=0.944) . 4. The better ear's mean value of pure speech fre-quency and the weighted values into different high frequency of working years on each group were compared, working years more than 10 years group was significantly higher than that of average thresholds of each frequen-cy band in 3-5 group (F=2.271, P=0.001) , 6-10 group (F=1.563, P=0.046) , the difference was statistically significant. The different high frequency weighted values were higher than those of the mean value of pure speech frequency, and the high frequency weighted 4 kHz+6 kHz had the highest frequency difference, with an average increase of 2.83 dB. 5. The diagnostic rate into weighted different high frequency was higher in the mild, moderate and severe grades than in the pure speech frequency. In the comparison of diagnosis for mild occupational noise-induced deafness, in addition to the weighted 3 kHz high frequency (χ²=3.117, P=0.077) had no significant difference, the weighted 4 kHz (χ²=10.835, P=0.001) , 6 kHz (χ²=9.985, P=0.002) , 3 kHz+4 kHz (χ²=6.315, P=0.012) , 3 kHz+6 kHz (χ²=6.315, P=0.012) , 4 kHz+6 kHz (χ²=9.985, P=0.002) , 3 kHz+4 kHz+6 kHz (χ²=7.667, P=0.002) were significantly higher than the diagnosis rate of the mean value of pure speech frequency. There was no significant difference between the two groups in the moderate and se-vere grades (P>0.05) . Conclusion Bring into different high frequency hearing threshold weighted value in-creases the diagnostic rate of occupational noise-induced deafness, the weighted 4 kHz, 6 kHz and 4 kHz+ 6 kHz high frequency value affects the result greatly, and the weighted 4 kHz+6 kHz high frequency hearing threshold value is maximum the effect on occupational noise-induced deafness diagnosis.

OBJECTIVE: To analyze the growth arrest and DNA damage gene 45( GADD45) mRNA expression in peripheral blood of radiation workers,and its relationship with exposure dose. METHODS: Using a typical sampling method,97 radiation workers from a hospital of Guangdong were selected as radiation group,48 hospital administrative staff without exposure to radiation and other occupational hazard factors were selected as control group. The real-time quantitative polymerase chain reaction was used to detect GADD45 mRNA expression of two groups. With the use of thermoluminescence dosimetry,we detected and collected personal dose data of radiation group over the past year. RESULTS: The GADD45 mRNA relative expression of the radiation group was higher than that of the control group( P < 0. 01).There was no correlation between GADD45 mRNA relative expression and factors such as personal dose,sex,age,length of service,smoking,and alcohol drinking( P > 0. 05). CONCLUSION: The ionizing radiation can lead to up-regulation of GADD45 mRNA expression in peripheral blood of radiation workers,but there was no linear relationship between GADD45 mRNA expression and its personal dose.