Analyzing the characteristics and influencing factors of high frequency hearing loss among noise-exposed workers in an urban rail transit enterprise / 中国职业医学

{L-End}Objective To analyze the characteristics of hearing loss and the influencing factors of high-frequency hearing loss (HFHL) among noise-exposed workers in an urban rail transit enterprise over five consecutive years. {L-End}Methods A total of 1 268 noise-exposed workers, who exposed to the average noise intensity of <85.0 dB(A), in an urban rail transit enterprise was selected as the research subjects using a judgment sampling method. The pure-tone audiometry results from 2019 to 2023 were collected to analyze the result of hearing loss. The influencing factors of HFHL (average hearing threshold ≥40.0 dB at high frequencies in both ears) were analyzed using the generalized estimating equations (GEE). {L-End}Results The detection rates of threshold elevations at frequencies of 0.5-6.0 kHz increased with increasing frequency from 2019 to 2023 (all P<0.01), with the highest detection rate at 6.0 kHz. The detection rate of speech frequency hearing loss (hearing threshold weighted value≥26.0 dB in the better ear) was 0.1%, 0.0%, 0.4%, 0.2%, and 0.2%, respectively. The detection rate of HFHL from 2019 to 2023 was 2.4%, 2.8%, 2.8%, 2.1%, and 2.8%, respectively. The GEE analysis results showed that the risk of HFHL of the workers in 2022 and 2023 was lower than that in 2019 (all P<0.01), with the odds ratios and 95% confidence intervals ［OR (95%CI)］ of 0.57 (0.41-0.81) and 0.65 (0.48-0.87), respectively. The risk of HFHL was higher among vehicle maintenance worker than train drivers (P<0.05), with OR (95%CI) of 2.37 (1.18-4.77). The risk of HFHL increased with age and length of service among the workers (all P<0.05), with the OR (95%CI) of 2.05 (1.22-3.46) and 1.69 (1.12-2.54), respectively. No interaction was found between type of job and age, type of job and length of service, or age and length of service in the risk of HFHL among the research subjects(all P<0.05). {L-End}Conclusion Noise exposure below the national occupational exposure limits can lead to hearing loss in noise-exposed workers of urban rail transit enterprises, possibly affecting the hearing threshold at 6.0 kHz first. The influencing factors for HFHL in workers of rail transit are age, length of service, and type of job. There is a dose-effect relationship with age and length of service.

Effects of electroacupuncture treatment on cortisol and inflammatory cytokines in patients with occupational noise-induced deafness combined with depressive symptoms / 中国职业医学

OBJECTIVE: To explore the effect of electroacupuncture treatment on the levels of cortisol and immune factors in patients with occupational noise-induced deafness(ONID) combined with depressive symptoms. METHODS: A total of 78 ONID patients combined with depressive symptoms were randomly divided into control group(40 cases) and electroacupuncture group(38 cases) by a random number table method. The control group received routine therapy, while the electroacupuncture group was treated with routine therapy plus electroacupuncture on alternate days, 3 times a week for 4 consecutive weeks. The levels of salivary cortisol, as well as the serum levels of cortisol, tumor necrosis factor alpha(TNF-α), interleukin-6(IL-6) and C-reactive protein(CRP) of the two groups were observed and compared before and after treatment. RESULTS: Before treatment, the levels of saliva cortisol in the morning and night, and the serum levels of cortisol, IL-6, TNF-α and CRP in the two groups were compared, and the differences were not statistically significant(P>0.05). After treatment, the serum cortisol level of patients in electroacupuncture group reduced than that before treatment in the same group(P<0.05). However, there was no significant difference in the levels of salivary cortisol in the morning and night, and serum cortisol before and after treatment both in control group and electroacupuncture group(P>0.05). After treatment, the serum levels of IL-6 and TNF-α decreased in electroacupuncture group as compared with those before treatment and those after treatment in control group(P<0.01). CONCLUSION: Electroacupuncture treatment could reduce the levels of TNF-α and IL-6 in serum of ONID patients combined with depressive symptoms. The regulation of electroacupuncture on the inflammatory cytokines may be one of the mechanisms in treating ONID combined with depressive symptoms.

Changes of hemorheology and blood lipid index in patients with occupational hand-arm vibration disease / 中国职业医学

OBJECTIVE: To investigate the changes of hemorheology and blood lipid index in patients with occupational hand-arm vibration disease(OHAVD). METHODS: A total of 78 patients with OHAVD were selected as the OHAVD group, and 78 workers without hand transmitted vibration exposure were selected as control group by judgment sampling method. The hemorrheology and blood lipid indexes of the two groups were detected. RESULTS: The whole blood viscosities(low-, medium-and high-shear), hematocrit, erythrocyte aggregation index, and abnormal rate of whole blood viscosities(mid-and high-shear) in the OHAVD group were higher in the OHAVD group than that in the control group(P<0.05). The erythrocyte deformability index and erythrocyte electrophoresis index were lower in the OHAVD group than that of the control group(P<0.05). In the vibration-induced white finger(VWF) subgroup of the OHAVD group, the whole blood viscosity(low-, medium-and high-shear), hematocrit were increased(P<0.05), and the abnormal rate of whole blood viscosity(high-shear) was higher(P<0.017) than that of the control group.The whole blood viscosity(medium shear), hematocrit and erythrocyte aggregation index were increased in the non-VWF subgroup than that of the control group(P<0.017). The concentration of low density lipoprotein cholesterol in the OHAVD group and non-VWF subgroup was higher than that in the control group(P<0.05). The whole blood viscosity(low-, medium-and high-shear), hematocrit, erythrocyte deformability index, erythrocyte aggregation index and erythrocyte electrophoresis index were not correlated with the length of service and age in the OHAVD group(P>0.05). CONCLUSION: The changes of hemorheological properties and blood lipids in OHAVD patients may be associated with vibration vascular injury.

Occupational exposure limits of methyl t-butyl ether in workplace air / 中国职业医学

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.

The role of acoustic impedance test in the diagnosis for occupational noise induced deafness / 中华劳动卫生职业病杂志

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.

Effect of delayed pre-job occupational health examination on results of radiation exposed workers / 中国职业医学

OBJECTIVE: To explore the effect of delayed pre-job occupational health examination on occupational health surveillance by analyzing the results of pre-job occupational health examinations in radiation exposed workers. METHODS: A convenience sampling method was used to select 1 385 radiation workers as the research subjects in Guangdong Province in 2016 at a pre-job occupational health examination. Workers who did not engage in radiation work were selected as control group. Workers who engaged in radiation work but did not take pre-job occupational health examinations were selected as observation group. The difference of the results of occupational health examination between the two groups was analyzed. RESULTS: The proportion of the observation group was 55. 8%(773/1 385). The abnormal rates of the white blood cell( WBC) count,“double + ring”rate and lens in the observation group were higher than those in the control group(9. 3% vs 5. 7%,6. 0% vs 3. 6%,6. 2% vs 3. 6%,P < 0. 05),respectively. The WBC count in the observation group was lower than that in the control group [(6. 1 ± 1. 5) × 10~9/L vs(6. 7 ± 1. 5) × 10~9/L,P < 0. 01]. The contents of the thyroid stimulating hormone and triiodothyronine in the observation group were higher than those in the control group[(1. 3 ± 0. 4) m U/L vs(1. 2 ± 0. 3) m U/L,(1. 8 ± 0. 4) nmol/L vs(1. 7 ± 0. 5) nmol/L,P < 0. 01]. The tetraiodothyronine level in the observation group was lower than that in the control group [( 110. 8 ± 22. 4) nmol/L vs(113. 8 ± 23. 2) nmol/L,P < 0. 05]. CONCLUSION: The delay of pre-job occupational health examination of radiation exposed workers affects the examination results and the accuracy of basic health records.

Trend predication on incidence of occupational noise-induced deafness by ARIMA model / 中国职业医学

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.

Study the impacts of diagnosis on occupational noise-induced deafness after bring into the different high frequency hearing threshold weighted value / 中华劳动卫生职业病杂志

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.

Value of DNA content in comet tail in predicting changes in blood cell counts in workers exposed to benzene / 中华劳动卫生职业病杂志

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.

Correlation between GADD45 mRNA expression and exposure dose in peripheral blood of radiation workers / 中国职业医学

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.

Comparative study on the diagnostic criteria of occupational noise-induced deafness between version 2014 and version 2007 / 中国职业医学

OBJECTIVE: To analyze the impact of GBZ 49-2014 Diagnosis of Occupational Noise-induced Deafness and GBZ49-2007 Diagnostic Criteria of Occupational Noise-induced Deafness on the diagnosis of occupational noise-induced deafness( ONID). METHODS: A total of 84 individuals,who were workers exposed to noise and diagnosed as observation subjects by GBZ 49-2007 were selected as the subjects of study by judgment sampling. They were diagnosed based on the criteria of GBZ 49-2014 and GBZ 49-2007. The impact of different diagnostic audiometry,different age and gender correction methods and the inclusion of a weighting of 0. 1 high-frequency 4. 0 k Hz hearing threshold of GBZ 49-2014 on the diagnosis of ONID was analyzed. RESULTS: The binaural high frequency threshold average( BHFTA) calculated by GBZ 49-2014 were lower than that of GBZ 49-2007 [( 52. 1 ± 10. 3) vs( 52. 8 ± 10. 1) d B,P < 0. 05 ],but monaural threshold of weighted value( MTWV) of the good ear calculated by GBZ 49-2014 were higher than speech frequency threshold average( SPTA) of the good ear of GBZ 49-2007 [( 23. 2 ± 4. 1) vs( 19. 3 ± 4. 8) d B,P < 0. 01]. All of the 84 patients had BHFTA ≥40 d B and SPTA < 26 d B when diagnosed by GBZ 49-2007,and could not be diagnosed as ONID. A total of33. 3% patients had BHFTA ≥40 d B and MTWV ≥26 d B when diagnosed by GBZ 49-2014 which could be diagnosed as mild ONID. The detection rate of ONID was 21. 4% to 34. 5%( P < 0. 01) when the threshold of 4. 0 k Hz was used as the weighting diagnostic threshold of hearing in the case of using different diagnostic audiograms and different age and sex correction methods. CONCLUSION: A high-frequency hearing threshold of 4. 0 k Hz with a weighting of 0. 1 was included in GBZ 49-2014 as a diagnostic threshold,which reduced the diagnostic threshold of ONID.

The application of low-dose multi spiral CT chest scan in pneumoconiosis / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To apply low-dose multi spiral computed tomography (MSCT) chest scans in the early diagnosis and differential diagnosis of pneumoconiosis.</p><p><b>METHODS</b>One hundred and twenty dust-exposed volunteers were examined by MSCT chest scans at conventional dose and low dose, and the results of conventional-dose scans were set as the gold standard. Comparative analysis was performed on the major CT findings and quality of post-processing images, including 1.5 mm and 5.0∼10.0 mm thick high -resolution reconstructed images, multiplanar reformat images, and maximum intensity projection images.</p><p><b>RESULTS</b>One hundred and twenty cases of small circular shadows, 36 cases of ribbon shadows in pulmonary parenchyma, 1 case of honeycombing shadow, and 13 cases of big shadows were all showed on low -dose MSCT. But 94 (95.9%) of 98 cases of interlobular septal thickening shadows and 98 (93.3%) of 105 cases of short branched shadows were detected on low-dose MSCT. There were no significant differences in display of the mentioned large and small shadows between low-dose scans and conventional-dose scans (P > 0.05). Eighty-five cases of small airway disease, 8 cases of pulmonary inflammatory lesions, and 47 cases of hilar and mediastinal lymph node swelling were all detected by MSCT. As for the 46 cases of emphysema, 38 (82.6%) were shown. The low-dose MSCT images of 1.5 mm thickness had more artifacts than those of other thickness. The radiation dose of low-dose MSCT was about 1/3-1/5 of that in the conventional-dose MSCT.</p><p><b>CONCLUSION</b>There is no difference in display of pneumoconiosis between low-dose and conventional-dose MSCT chest scans. With lower radiation dose, low-dose MSCT can be applied in the diagnosis of pneumoconiosis.</p>