Comparative outcomes of obese and non-obese patients with lumbar disc herniation receiving full endoscopic transforaminal discectomy: a systematic review and meta-analysis

OBJECTIVE

This study aimed to assess the impact of full endoscopic transforaminal discectomy (FETD) on clinical outcomes and complications in both obese and non-obese patients presenting with lumbar disc herniation (LDH).

METHODS

A systematic search of relevant literature was conducted across various primary databases until November 18, 2023. Operative time and hospitalization were evaluated. Clinical outcomes included preoperative and postoperative assessments of the Oswestry Disability Index (ODI) and visual analogue scale (VAS) scores, conducted to delineate improvements at 3 months postoperatively and during the final follow-up, respectively. Complications were also documented.

RESULTS

Four retrospective studies meeting inclusion criteria provided a collective cohort of 258 patients. Obese patients undergoing FETD experienced significantly longer operative times compared to non-obese counterparts (P = 0.0003). Conversely, no statistically significant differences (P > 0.05) were observed in hospitalization duration, improvement of VAS for back and leg pain scores at 3 months postoperatively and final follow-up, improvement of ODI at 3 months postoperatively and final follow-up. Furthermore, the overall rate of postoperative complications was higher in the obese group (P = 0.02). The obese group demonstrated a total incidence of complications of 17.17%, notably higher than the lower rate of 9.43% observed in the non-obese group.

CONCLUSION

The utilization of FETD for managing LDH in individuals with obesity is associated with prolonged operative times and a higher total complication rate compared to their non-obese counterparts. Nevertheless, it remains a safe and effective surgical intervention for treating herniated lumbar discs in the context of obesity.

[Baseline survey of psychosocial factors levels and their health effects in a cohort study of natural gas field workers]

Objective: To investigate the level of psychosocial factors in workplace and their health effects among workers in a natural gas field. Methods: A prospective and open cohort of natural gas field workers was established to study the level of workplace psychosocial factors and their health effects, with a follow-up every 5 years. In October 2018, a cluster sampling method was used to conduct a baseline survey of 1737 workers in a natural gas field, including a questionnaire survey on demographic characteristics, workplace psychosocial factors and mental health outcomes, physiological indicators such as height and weight, and biochemical indicators such as blood routine, urine routine, liver function and kidney function. The baseline data of the workers were statistically described and analyzed. The psychosocial factors and mental health outcomes were divided into high and low groups according to the mean score, and the physiological and biochemical indicators were divided into normal and abnormal groups according to the reference range of normal values. Results: The age of 1737 natural gas field workers was (41.8±8.0) years old, and the length of service was (21.0±9.7) years. There were 1470 male workers (84.6%). There were 773 (44.5%) high school (technical secondary school) and 827 (47.6%) college (junior college) graduates, 1490 (85.8%) married (including remarriage after divorce), 641 (36.9%) smokers and 835 (48.1%) drinkers. Among the psychosocial factors, the detection rates of high levels of resilience, self-efficacy, colleague support and positive emotion were all higher than 50%. Among the mental health outcomes evaluation indexes, the detection rates of high levels of sleep disorder, job satisfaction and daily stress were 41.82% (716/1712), 57.25% (960/1677) and 45.87% (794/1731), respectively. The detection rate of depressive symptoms was 22.77% (383/1682). The abnormal rates of body mass index (BMI), triglyceride and low density lipoprotein were 46.74% (810/1733), 36.50% (634/1737) and 27.98% (486/1737), respectively. The abnormal rates of systolic blood pressure, diastolic blood pressure, uric acid, total cholesterol and blood glucose were 21.64% (375/1733), 21.41% (371/1733), 20.67% (359/1737), 20.55% (357/1737) and 19.17% (333/1737), respectively. The prevalence rates of hypertension and diabetes were 11.23% (195/1737) and 3.45% (60/1737), respectively. Conclusion: The detection rates of high level psychosocial factors in natural gas field workers are high, and their effects on physical and mental health remain to be verified. The establishment of a cohort study of the levels and health effects of psychosocial factors provides an important resource for confirming the causal relationship between workplace psychosocial factors and health.

[A descriptive analysis of tea consumption in adult twins in China]

Objective: To describe the distribution characteristics of tea consumption in adult twins recruited in the Chinese National Twin Registry (CNTR) and provide clues to genetic and environmental influences on tea consumption. Methods: Enrolled in CNTR during 2010-2018, 25 264 twin pairs aged 18 years and above were included in subsequent analysis. Random effect models were used to estimate tea consumption in the population and regional distribution characteristics. The concordance rate of the behavior and difference in consumption volume of tea within pairs were also described. Results: The mean age of all subjects was (35.38±12.45) years old. The weekly tea consumers accounted for 17.0%, with an average tea consumption of (3.36±2.44) cups per day. The proportion of weekly tea consumers was higher among males, 50-59 years old, southern, urban, educated, and the first-born in the twin pair (P<0.05), and lower among unmarried individuals (P<0.001). Within-pair analysis showed that the concordance rate of tea consumption of monozygotic (MZ) twins was higher than that of dizygotic (DZ) twins and the overall heritability of tea consumption was 13.45% (11.38%-15.51%). Stratified by the characteristics mentioned above, only in males, the concordance rate of MZ showed a tendency to be greater than that of DZ (all P<0.05). The differences in consumption volume of tea within twin pairs were minor in MZ among males (P<0.05), while the differences were not significant in female twins. Conclusion: There were discrepancies in the distribution of tea consumption among twins of different demographic and regional characteristics. Tea consumption was mainly influenced by environmental factors and slightly influenced by genetic factors. The size of genetic factors varied with gender, age, and region, and gender was a potential modified factor.

[A case-control study on the relationship between DNA methylation and occupational noise hearing loss]

Objective: To explore the relationship between DNA methylation and occupational noise-induced hearing loss. Methods: A case-control study was conducted. People with hearing loss induced by occupational noise were recruited as the case group and those with normal hearing but still exposed to occupational noise were recruited as the control group. A total of 60 participants were included, of which 30 participants were in the case group and 30 in the control group. The methylation level was detected by 850k genome-wide DNA methylation chip technology. The significance of differential methylated position (DMP) was tested by R-packet 'Champ'. The differential methylated region (DMR) was analyzed by using Champ's Bumphunter algorithm. Cluster profiler was used to analyze the gene list for GO and KEGG pathway enrichment. Results: There was significant difference between two groups in binaural high-frequency average hearing threshold (P<0.05), but there was no significant difference in age, smoking, drinking, hypertension, physical exercise and cumulative noise exposure. The results of DMP and DMR analysis showed that 713875 sites were detected in the case group and the control group, and 439 methylation sites with significant difference, accounting for 0.06%; 650 regions were detected, and 72 methylation regions with significant differences, accounting for 11.08%. Compared with the control group, the results of GO enrichment analysis showed that the case group had statistically significant differences in four pathways: axogenesis of projection neurons in the central nervous system, neuronal development in the central nervous system, axogenesis of neurons in the central nervous system and neuronal differentiation in the central nervous system. KEGG enrichment analysis showed that there were significant differences in sphingolipid metabolism, aldosterone synthesis and secretion, primary bile acid biosynthesis pathway between the case group and the control group. Conclusion: The occurrence of occupational noise-induced hearing loss may be related to the regulation of gene expression related to axogenesis of projection neurons in the central nervous system, development of neurons in the central nervous system, axogenesis of neurons in the central nervous system, differentiation of neurons in the central nervous system, sphingolipid metabolism, aldosterone synthesis and secretion, primary bile acid biosynthesis and gene methylation related to metabolism.

[A descriptive analysis on coronary heart disease in adult twins in China]

Objective: To describe the distribution characteristics of coronary heart disease in adult twins recruited from Chinese Twin Registry (CNTR), and provide clues and evidence for the effect of genetic and environmental influences on coronary heart disease. Methods: By using the data of CNTR during 2010-2018, a total of 34 583 twin pairs aged ≥18 years who completed questionnaire survey and had related information were included in the current study to analyze the population and area distribution characteristics of coronary heart disease. Random effect models were used to compare the differences between groups. The concordane rate of coronary heart disease were calculated respectively in monozygotic (MZ) twin pairs and dizygotic (DZ) twin pairs to estimate the heritability. Results: The twin pairs included in this analysis were aged (34.2±12.4) years. The overall prevalence rate of coronary heart disease in twin pairs was 0.7%. Twin pairs who were women, older, obese and lived in northern China had higher prevalence of coronary heart disease (P<0.05). Intra-pair analysis in the same-sex twin pairs found that the concordane rate of coronary heart disease was higher in MZ twin pairs (25.3%) than in DZ twins (7.4%), and the difference was statistically significant (P<0.001). The overall heritability of coronary heart disease was 19.3% (95%CI: 11.8%-26.8%). Stratified by gender, age and area, the concordane rate was still higher in MZ twin pairs than in DZ pairs. Participants who were women, aged 18-30 years or ≥60 years and lived in northern China had a higher heritability of coronary heart disease. Conclusion: The distribution of coronary heart disease in twin pairs differed in populations and areas. The prevalence of coronary heart disease was affected by genetic factors, but the effect varied with age, gender and area.

[A descriptive analysis on type 2 diabetes in twins in China]

Objective: To describe the distribution characteristics of type 2 diabetes in twins in Chinese National Twin Registry (CNTR), provide clues and evidence for revealing the influence of genetic and environmental factors for type 2 diabetes. Methods: Of all twins registered in the CNTR during 2010-2018, a total 18 855 twin pairs aged ≥30 years with complete registration information were included in the analysis. The random effect model was used to describe the population and area distribution characteristics and concordance of type 2 diabetes in twin pairs. Results: The mean age of the subjects was (42.8±10.2) years, the study subjects included 10 339 monozygotic (MZ) twin pairs and 8 516 dizygotic (DZ) twin pairs. The self-reported prevalence rate of type 2 diabetes was 2.2% in total population and there was no sighificant difference between MZ and DZ. Intra-twin pairs analysis showed that the concordance rate of type 2 diabetes was 38.2% in MZ twin pairs, and 16.0% in DZ twin pairs, the difference was statistically significant (P<0.001). The concordance rate of type 2 diabetes in MZ twin parts was higher than that in DZ twin pairs in both men and women, in different age groups and in different areas (P<0.05). Further stratified analysis showed that in northern China, only MZ twin pairs less than 60 years old were found to have a higher concordance rate of type 2 diabetes compared with DZ twin pairs (P<0.05). In southern China, the co-prevalence rate in male MZ twin pairs aged ≥60 years was still higher than that in DZ twin pairs (P<0.05). Conclusion: The twin pairs in this study had a lower self-reported prevalence of type 2 diabetes than the general population. The study results suggested that genetic factors play a role in type 2 diabetes prevalence in both men and women, in different age groups and in different areas, however, the effect might vary.

[Application and prospect of multiomics techniques in susceptibility to occupational noise hearing loss]

With the continuous innovation of technology, genomics and other omics techniques, such as transcriptomics, proteomics, and metabolomics, are increasingly becoming an important basis for precision medicine. Current research on susceptibility to occupational noise hearing loss (ONHL) has focused on genomics. Building the future of precision medicine is the focus of current ONHL research. Compared to single-omics studies, the use of multi-omics analysis can provide an integrated flow of information on ONHL susceptibility. This paper outlines the advantages and limitations of different histological techniques and the application of each histology in the disease, and focuses on the feasibility of applying multi-omics techniques in ONHL susceptibility research. The analysis of multi-omics techniques can better guide the comprehensive understanding of the disease in clinical research.

[Effect of occupational stress on depression in gas field workers]

Objective: To explore the occurrence level of depressive symptoms and it's influencing factors among gas field workers. Methods: In October 2018, a cross-sectional study was conducted in 1726 gas field workers from a gas field by using cluster sampling method. Questionaire was used to evaluate the individual factors, depressive symptoms, occupational stress factors and stress regulatory factors. The correlation between depressive symptoms and occupational stress was analyzed. Multivariate logistic regression was used to analyze the influencing factors of depressive symptoms. Results: The depressive symptoms score of gas field workers was 12.00 (7.00, 19.00) point. Correlation analysis revealed that depressive symptoms score was positively related to sleep disorders (r=0.598) , effort (r=0.186) , daily tension (r=0.478) , negative affectivity (r=0.565) , social support (r=0.446) and monotony of work (r=0.484) (P<0.01) . And it was negatively related to reward (r=-0.386) , work stability (r=-0.294) , promotion opportunities (r=-0.258) , positive affectivity (r= -0.310) , self-efficacy (r=-0.312) , contral strategy (r=-0.268) , support strategy (r=-0.209) and job satisfaction (r=-0.398) (P<0.01) . Multivariate logistic regression analysis revealed that sleep disorder, high negative affectivity, low support from colleagues, low support from family, high monotony of work and high daily tension were the risk factors for depressive symptoms of gas field worker (OR=3.423, 95%CI: 2.644-4.397; OR=2.847, 95%CI: 2.200-3.683; OR=1.646, 95%CI: 1.215-2.116; OR=1.496, 95%CI: 1.164-1.923; OR=1.578, 95%CI: 1.227-2.303; OR=1.903, 95%CI: 1.480-2.440; P<0.01) . High work stability, high self-efficacy and high job satisfaction were protective factors for depressive symptoms of gas field workers (OR=0.752, 95%CI: 0.591-0.958; OR=0.590, 95%CI: 0.465-0.749; OR=0.718, 95%CI: 0.516-0.999; P<0.05) . Conclusion: Occupational stress factors have a great influence on the depressive symptoms of gas field workers. Increased work stability, self-efficacy and job satisfaction could reduce the risk of depressive symptoms.

[Correlation between social support and occupational stress among gas production workers in the field]

Objective: To investigate the level of social support and its correlation with occupational stress among gas production workers in the field. Methods: In October 2018, the cluster sampling method was used to perform a cross-sectional survey for 1726 gas production workers in the field, and related data of these workers were collected, including age, education level, marital status, level of social support, and related factors for occupational stress. A Spearman's rank correlation analysis was used to investigate the correlation between social support and occupational stress, and the levels of occupational stress-related factors were compared between the groups with different social support scores. Results: The gas production workers in the field had a median (25th percentile, 75th percentile) social support score of 24.00 (19.00, 28.00) , and there was a significant difference in social support score between the workers with different posts or work shifts (P<0.01) . Social support score was positively correlated with effort, daily stress, negative emotion, and job routinization (P<0.05) and was negatively correlated with job satisfaction, reward, working stability, and promotion opportunity (P<0.05) . The group with a high social support score had significantly higher scores of effort, job routinization, sleep disorders, and daily stress than the other two groups (P<0.01) , and the group with a low social support score had significantly higher scores of reward, self-efficacy, positive affection, and job satisfaction than the other two groups (P<0.01) . Conclusion: High-level social support plays an important role in alleviating occupational stress and protecting mental health among gas production workers in the field.

[Interaction of shift work and psychological capital on abnormal glucose and lipid metabolism among natural gas field workers]

Objective: To explore the interaction between shift work and psychological capital on abnormal glucose and lipid metabolism. Methods: A convenient sampling survey of demographics characteristics, shift work and psychological capital was conducted on 1 415 natural gas field workers by questionnaire in October 2018,and their physiological and biochemical indexes were measured according to standard norms. Multivariate logistic regression model was used to analyze the interaction between shift work and psychological capital on abnormal glucose and lipid metabolism. Results: For 1 415 subjectsthe prevalence of abnormal blood glucose was 21.2%, the prevalence of diabetes was 8.3%.The prevalence of abnormal total cholesterol was 40.4%, the prevalence of hypercholesterolemia was 11.3%.The prevalence of abnormal triglyceride was 41.6%, the prevalence of hypertriglyceridemia was 24.7%.The detection rate of Low-density Lipoprotein was 17.3%, the detection rate of Low-density Lipoprotein was 4.0%, and the detection rate of high-density Lipoprotein was 1.3%. Multiple logistic regression model analysis showed that shift work, the low level of self-efficacy and the low level of optimism was positively associated with abnormal blood glucose, respectively (P<0.05). Shift work was positively associated with abnormal triglyceride (P<0.05). However, there was no interaction between shift work, low self-efficacy, low hope, low resilience, and low optimism on abnormal glucose and lipid metabolism. Conclusion: Shift work was a risk factor of abnormal blood glucose and triglyceride, self-efficacy and optimism were protective factors of abnormal blood glucose. There was no multiplicative interaction between shift work and psychological capital on abnormal glucose and lipid metabolism in the study population.

[A preliminary study on establishment of the Core Occupational Stress Scale (COSS) norms for manufacturing and medical workers in China]

Objective: To establish the Core Occupational Stress Scale (COSS) norm values for manufacturing and medical workers. Methods: A total of 10 316 manufacturing workers of 20 companies from 7 provincial capital cities and 5 031 medical workers of 19 hospitals from 4 provincial capital cities were investigated using a stratified sampling method. Questionnaire information including occupational stress was collected. Norms of mean, percentile and T scores were calculated for COSS total and sub-dimension scores by different demographic characteristics. Based on the normal distribution, cut points of x¯+0.5s, x¯+s, x¯+1.5s of COSS total scores were calculated to classify the degree of occupational stress. Results: The COSS total scores were (45.48±8.16) and (45.71±8.46). The 50th percentiles were both 46, and T score ranges were (15-92) and (16-91), respectively, for manufacturing and medical workers. When the total score was<50, 50-53, 54-57, and >57 for manufacturing worker, or<50, 50-54, 55-58, and >58 for medical workers, occupational stress would be classified into none, mild, moderate, and severe levels. Conclusion: Compatible with the national condition of China, as well as the principles of psychological measurement, these norm values for manufacturing and medical workers could provide theoretical support and practical guideline on occupational mental health promotion.

[Development of the Core Occupational Stress Scale for occupational populations in China]

Objective: To develop the Core Occupational Stress Scale (COSS) for key occupational populations, and to assess the reliability and validity of COSS in China. Methods: According to the literature review, in-depth interview and expert evaluation, the item pool of COSS was established. A total of 20 981 employees (3 703 employees from 2018 and 17 178 employees from 2019) of manufacturing, medical, and traffic polices, etc. from Beijing, Tianjin, Shanghai, Chongqing, Jiangsu, Shandong, Zhejiang, Hunan, Guangdong and Hubei were investigated using convenient sampling of those participating in general or occupational health examination of the day. Item differential test and exploratory factor analysis (EFA) were used to screen items from the item pool; confirmatory factor analysis (CFA) was used to test structure validity; criterion and convergent validity were tested by Pearson correlation. Cronbach's α coefficient was used to test the reliability of the scale. Results: The EFA suggested a four-factor structure for a 17-item version of COSS, which were social support, organization and reward, demand and effort, and control. It explained 62.06% of the total variance and factor loadings ranged from 0.447 to 0.918. The CFA confirmed the hypothesized four-factor model (GFI=0.904, CFI=0.912, RMSEA=0.079). The COSS scores were positively correlated with burnout, depressive symptoms, and effort-reward imbalance scores with r ranging from 0.357 to 0.567 (P<0.05). The total COSS and each dimension of Cronbach's α coefficients were 0.772-0.896. Conclusions: The COSS has good reliability and validity and can be used as an occupation stress assessment for occupational populations in China.

[Correlation of job monotony and social support on daily hassle: a cross-sectional study based on natural gas field workers]

Objective: To explore the correlation of job monotony and social support on daily hassle. Methods: A convenient sampling survey of demographics characteristics, job monotony, social support and daily hassle was conducted on 1 466 natural gas field workers by questionnaire in October; 2018. Multivariate logistic regression model was used to analyze the correlation of job monotony and social support on daily hassle. Results: The age of 1 466 subjects was (44.47±8.0) years and the length of service was (20.46±5.77) years. There were 258(17.6%), 173(11.8%), 799(54.5%), 120(8.2%) and 116(7.9%) subjects from production and marketing department, processing plant, branch, maintenance department and emergency center respectively. There were 374(25.5%) and 1 092(74.5%) subjects with high and low level of job monotony, and 398(27.1%), 648(44.2%) and 420(28.6%) subjects with high, middle and low level of social support. There were 464(31.7%) and 1 002(68.3%) subjects with high and low daily tension respectively. Compared with the low level of job monotony, the high level of job monotony had a higher risk of daily hassle(OR=4.83,P<0.001), and compared with the high level of social support, the middle and low level of social support had a higher risk of daily hassle(OR=1.25, 2.24,P<0.05). Conclusion: Job monotony and social support were associated with daily hassle.

[Using the experience of industrilized countries for reference to promote the prevention and control of occupational stress from research to practice]

Occupational stress is one of the major occupational health problems in industrialized countries. In Europe, the United States, Japan, and other countries, occupational stress has been included in the prevention and control of occupational hazards in the workplace. This problem has also become a major risk factor affecting the physical and mental health of the working population in China. Over the last three decades, China had carried out a lot of research on occupational stress and made significant progress, but there is still a big gap between China and industrialized countries in terms of theoretical research on occupational stress, development of measurement tools, research topics and methods, formulation of regulations and standards, and practice of prevention and control. Articles in this key issue report the research on the core scale of occupational stress measurement for the Chinese working population, the scale scoring norm of manufacturing and medical personnel, the research on the relationship between positive psychology variables, and occupational stress and its role in the relationship between occupational stress and health outcomes.

[Airway parameters and reference value range of high-resolution CT reconstruction in general population]

Objective: To investigate the measurement of small airways by high-resolution CT and image post-processing software. Screen and analyze the reconstructed airway parameters in order to find the best imaging biomarker parameters of small airway changes and calculate the reference value range; meanwhile, explore its influencing factors. Methods: From a water plant and a medical school, 169 cases of the general population aged 20 to 60 were selected as research objects, and questionnaire surveys and CT tests were performed, and CT data were reconstructed with image post-processing software. The reference value range of the general population was evaluated, and a linear mixed effect model was used to adjust the age, gender, height, BMI, and smoking status, and analyze the influencing factors of airway parameters. Results: The ratio of sixth-grade tracheal wall area to total tracheal area in the Left B1+2 to carina was (53.01±13.35) %, Left B9 to carina was (50.44±12.98) %, Right B1 to carina was (52.73±12.22) %, and Right B9 to carina was (52.93±11.85) %. The ratio of nineth-grade tracheal wall area to total tracheal area in the Left B1+2 to carina was (44.08±14.66) %, Left B9 to carina was (42.44±15.89) %, Right B1 to carina was (46.51±14.03) %, and Right B9 to carina is (43.54±15.87) %. BMI affect the area of the tracheal wall, all p value<0.05. Conclusion: High-resolution CT small airway morphology can make a preliminary assessment of the susceptible population of small airway-related diseases based on a range of reference values, and prevent and control it in combination with influencing factors.

[Application of an occupational health risk assessment method in dioctyl phthalate producing enterprise]

Objective: To find the risk assessment model of [di (2-ethylhexyl) phthalate, DEHP] fitting well for producing companies. Methods: The Cluster Sampling method was used in selecting a DEHP producing company in the occupational health and workplace environment monitoring study conducted between July and August in 2017. Data was collected by site evaluating and workplace environment monitoring. According to GBZ/T 298-2017《Technical Guidelines for Occupational Health Risk Assessment of Chemical Hazards in the Workplace》, a qualitative assessment method and a semi-quantitative comprehensive index method were chosen as the models and were compared. Results: The occupational health risk of the two methods rated 4 (high risk) and 2 (negligible risk) . Conclusion: The semi-quantitative comprehensive index method is more comprehensive and accurate when used to assess the occupational health risk caused by DEHP.

[Analysis on the effect of sound insulation reconstruction in operation room of steel rolling production line in a steel plant]

Objective: To investigate the effect of sound insulation improvement on the noise exposure of workers in the operation room of hot rolling line for wide and heavy plate. Methods: From September 2019 to September 2017, based on the occupational health Survey, the data of 25 fixed operation rooms and workers in operation rooms of a steel rolling production line were collected retrospectively, the noise exposure levels before and after the improvement of sound insulation were statistically analyzed. Results: The noise exposure value of the workers, the qualified rate of 0 Grade 8 hours equivalent noise (L(EX, 8 h)) ≤85 dB (A) and the qualified rate of the design limit value of the operation room were all higher than those before the modification, the difference was statistically significant (P<0.01) , after the renovation, the Class II and above noise hazards were eliminated, the equivalent continuous a sound level (L(Aeq, 8 h)) >75 dB (A) of the workers in the operation room was 8h, and the noise level in the operation room still did not meet the Ergonomics limit standard. Conclusion: The improvement of sound insulation can effectively improve the working environment of noise workplace operating room and reduce the workers'noise exposure level.

[Prediction of KCNQ4gene polymorphism varies with CNE or noise exposure duration on the Risk of NIHL-Cox model analysis based on cohort study]

Objective: The purpose of this study was to explore the association between gene in the potassium recycling pathway 4 (KCNQ4) polymorphisms and the susceptibility to noise-induced hearing loss (NIHL) , and analysis the effect of cumulative noise exposure (CNE) and noise exposure duration on this association. Methods: A nested case-control study with 1∶1 matched was used based on the cohort of noise exposure in a steel factory. A total of 286 cases were selected as the group of hearing loss and 286 controls were chosen according to the matching standards of same gender, same type of work, age difference ≤ 5 years, noise exposure duration ≤ 2 years. The single nucleotide polymorphisms (SNPs) of rs4660468, rs4660470, rs34287852 in KCNQ4 were genotyped by SNPscan(TM) method. The codominant, dominant and recessive models were established to study KCNQ4 polymorphisms and the susceptibility to NIHL by single-factor conditional logistic regression analysis. The COX regression analysis was used to analyze the risk of developing NIHL in individuals with different genotypes along with the extending of noise exposure duration or CNE. Results: In the case of CNE≤96 dB (A) ·year, the risk of developing NIHL in individuals with TA genotype of rs4660470 was 2.197 times than individuals with TT genotypes (95%CI: 1.032~4.677) , and those with TA+AA and TT genotypes (HR=2.467, 95%CI: 1.025~5.934) With the increase of noise exposure duration, in rs4660470, individuals with TA genotype had a higher risk of suffering NIHL than those with TT genotype (HR=1.461, 95%CI: 1.061~2.011) , individuals with TA and/or AA genotype had a earlier risk of suffering NIHL than those with TT genotype. Conclusion: The mutant allele A of rs4660470 in KCNQ4 may be a risk factor for developing NIHL, CNE≤100 dB (A) ·year or the increase of noise exposure duration may further increase the risk of NIHL.

[Association between PON2 gene polymorphisms and susceptibility to noise-induced hearing loss]

Objective: To investigate the relationship between SNP and noise-induced hearing loss (NIHL) susceptibility in occupational noise exposure population in China. Methods: From 6297 for a certain steel works in contact with noise, contact length of 3 years or more and workplace noise exposure intensity of 80 dB (A) , ears or high frequency (3 000, 4 000, 6 000 Hz) average of hearing acuity 40 dB (HL) , or high frequency loss in both ears, on the basis of single whisper frequency (500, 1, 000, 2 000 Hz) average threshold of 26 dB (HL) or object as case group. A case-control study was designed with 1:1 matching. Subjects with the same gender, the same type of work, age ±5 years old, and working age ±2 years after noise exposure were selected as the control group. Subjects with any whisper frequency (500, 1, 000, 2, 000 Hz) whose hearing threshold in any frequency band was ≤25 dB (A) and whose average high-frequency hearing threshold in pure tone hearing test was <35 dB (A) were selected as the control group. Four sites of PON2 gene were genotyped by medium-and high-throughput SNP genotyping. Univariate logistic regression was used to analyze the relationship between single SNP polymorphism and NIHL. Results: A total of 286 case-control pairs were included. Smoking was statistically significant difference between cases and controls (P<0.001) . Conclusion: No statistical difference has been found between single SNP polymorphism and NIHL. At the level of greater than 92 dB of high noise exposure, rs7785846 (CT+TT) genotype is a risk factor for occupational noise deafness, and its OR is 2.74 (95%CI: 1.09-6.89) compared with wild homozygous type (CC) . Conclusion. The rs7785846 (CT+TT) genotype carriers of PON2 gene are more susceptible to hearing impairment when exposed to high noise intensity.

[Association between GSTP1 gene polymorphisms and susceptibility to noise-induced hearing loss]

Objective: To investigate the association between the single nucleotide polymorphisms (SNPS) at rs1695 and rs6591256 in glutathione S-transferase P1 (GSTP1) gene and susceptibility to noise-induced hearing loss in Chinese Han workers exposed to noise. Methods: Using the 1: 1 nested case-control study and taking 6297 workers exposed to noise in a steel plant in Henan province as the cohort study population in July 2019, we screened those who have been exposed to noise for ≥3 years and whose binaural high frequency (3000, 4000, 6000 Hz) average hearing threshold is ≥40 dB (A) into the case group. The control group was selected according to the matching criteria of the same sex, same type of work, and the age difference was not more than 5 years old, and the working age difference was not more than 2 years. 276 subjects were selected into the case group and the control group respectively. The medium and high throughout single nucleotide polymorphism typing technology (SNPscanTM technology) was used to detect the polymorphism of three nucleotide sites of GSR gene, and conditional logistic regression was used to analyze the relationship between single nucleotide polymorphism (SNP) and NIHL, and the relationship between different polymorphic sites and the risk of NIHL after adjusting covariates. After stratification with different cumulative noise exposure (CNE) , Conditional logistic regression analysis was used to analysis the risk of NIHL at different loci. Results: The mean and standard deviation of age of the selected subjects was (40.28±8.00) , the mean and standard deviation of noise-exposed working years was (18.7±8.92) years. The range of noise exposure levels and comulative noise exposure were 80.05-93.35dB (A) and 86.83-107.92 dB (A) ·year, respectively. Compared with the control group, there were no statistically significant differences in age, noise-exposured working years, intensity of noise exposure, CNE, gender, drinking, hypertension prevalence and noise exposure level in the hearing loss group (P>0.05) , while there were statistically difference in smoking, binaural high-frequency average hearing threshold and binaural speech frequency (P<0.05) . After adjusting for smoking, drinking, hypertension and other factors, in the co-dominant model, compared with GGgenotype, the risk of NIHL was higher in rs1002149 GT genotype and rs2251780 GA genotype (OR=1.558, 95%CI: 1.028-2.361; OR=1.550, 95%CI: 1.020-2.355, P<0.05) ; compared with TT/GT genotype, the rs1002149 TT genotype has a higher risk of developing NIHL (OR=1.494, 95%CI: 1.002-2.228, P<0.05) , while rs3779647 genotype had no relationship with the risk of NIHL (P>0.05) . In the equivalent sound level (L(Aeq)) of noise >85 dB (A) stratification, compared with GG genotype, carrying rs1002149 GT genotype and rs2251780 GT genotype has higher risk of nihl (OR=1.801, 95%CI: 1.093-2.967; OR=1.720, 95%CI: 1.050-2.817, P<0.05) . Haplotype analysis of two sites, rs1002149 and rs2251780, was not found to be related to NIIHL susceptibility. Conclusion: The allele G of rs1695 and rs6591256 may be risk factors of NIHL.

[Relationship research among CDH23 gene and the risk of noise-induced hearing loss]

Objective: To explore the relationship among CDH23 gene variation and the risk of noise-induced hearing loss (NIHL) . Methods: The nested case-control study was performed and this study followed a cohort of 6297 noise-exposed workers in a steel factory of Henan province in China from January 1, 2006 to December 31, 2015. In July 2019, subjects whose average hearing threshold were more than 40 dB in high frequency were defined as the case group, and subjects whose average hearing threshold were less than 35 dB in high frequency and less than 25 dB in speech frequency were defined as the control group. A nested case-control study which included 572 subjects was carried out, in which subjects consisted of 286 cases and 286 controls. 18 single nucleotide polymorphisms (SNPs) in CDH23 were selected and genotyped, then we analyzed the association among SNPs in CDH23, haplotypes in CDH23 and NIHL risk. Logistic regression was performed to analyze the main effects of SNPs and the interactions between CNE and SNPs adjusting cumulative noise exposure (CNE) , smoking, drinking, physical exercise and hypertension. Moreover, the association between haplotypes in CDH23 and NIHL risk were also analyzed. We ananlyzed the relationship amongst different SNP groups and NIHL risk using the generalized multifactor dimensionality reduction (GMDR) method. Results: The results suggested that significant associations were observed for rs3802711, rs3752751, rs3752752, rs11592462, rs10762480, rs3747867 for NIHL overall and/or various CNE strata by adjusting CNE, smoking, drinking, physical exercise and blood pressure. For rs3802711, workers exposure to noise carrying the AA/GA genotype of rs3802711 increased risk of NIHL than those carrying GG genotype (OR=3.121; 95%CI:1.054-9.239, P=0.035) in overall; In the stratified analysis of CNE (>97 dB (A) ·year at rs3802711 locus, workers exposure to noise carrying GA genotype (OR=2.056; 95%CI:1.226~3.448, P=0.006) and GA+AA/GA genotype (OR=2.221; 95%CI:1.340~3.681, P=0.002) increased NIHL risk. For rs11592462, workers exposure to noise carrying the GG genotype of rs11592462 increased risk of NIHL than those carrying CC genotype in overall (OR=3.951; 95%CI:1.104-14.137, P=0.04) ; workers exposure to noise carrying the GG genotype of rs11592462 increased risk of NIHL than those carrying CG+CC genotype in overall (OR=4.06; 95%CI:1.145-14.391, P=0.03) . After adjusting CNE, smoking, drinking, physical exercise and blood pressure, the haplotypes of CDH23 rs1227049, rs10999947, rs3752752, rs3752751, rs10762480, rs3802711, rs11592462, rs10466026, rs4747194, rs4747195 were not associated with the risk of NIHL. GMDR analysis showed no association between SNP combination and NIHL risk after adjusting CNE, smoking, drinking, physical exercise and blood pressure. Conclusion: Gene polymorphisms in CDH23 might associate significantly with the risk of NIHL.

[Association between GPX1 gene polymorphisms and noise-induced hearing loss]

Objective: To identify association between genetic polymorphism in the Glutathione peroxidase 1 gene (GPX1) and noise-induced hearing loss (NIHL) . Methods: A nested case control study was conducted based on a cohort of noise-exposed subjects. 392 cases were selected from the steel factory in Henan Province, 392 matched control subjects for each case were designated on the basis of the matched criterion including same gender, age (±5years) and duration of exposure to noise (±2years) . Two single nucleotide polymorphisms (SNPs) of GPX1 were genotyped by SNPscanTM multiplex SNP genotyping kit. Hardy-Weinberg equilibrium (HWE) tests were performed using Pearson's χ(2) for each SNP among control group, effects of genotypes of GPX1 on NIHL were analyzed by logistic regression. Results: All two SNPs were in HWE. After adjustment for covariates including smoking status, rs1987628 polymorphism was statistically significantly associated with the NIHL risk under codominant and Dominant inheritance models; In the subjects carrying rs1987628 GA genotype had a higher NIHL risk than those carrying the GG genotype, the adjusted OR value was 1.803 (95%CI 1.215-2.676, P=0.003) . And meanwhile, rs1987628 GA+AA genotype had a higher NIHL risk than those carrying the GG genotype, the adjusted OR value was 1.762 (95%CI 1.197-2.593, P=0.004) . Conclusion: It was suggested that genetic polymorphism in the GPX1 gene might be the genetic susceptible factor for NIHL.

[Association between GSTP1 gave polymorphisms and susceptibility to noise-induced hearing loss]

Objective: To investigate the association between the single nucleotide polymorphisms (SNPS) at rs1695 and rs6591256 in glutathione S-transferase P1 (GSTP1) gene and susceptibility to noise-induced hearing loss in Chinese Han workers exposed to noise. Methods: A 1: 2 matched nested case-control study was performed, which based on the cohort of 6297 workers exposed to noise in an iron and steel plant in Henan, China, who were followed up from January 1, 2006 to December 31, 2015. According to the criteria of binaural average high-frequency hearing threshold ≥40 dB, a total of 292 workers were enrolled as hearing loss group; after the adjustment for sex, type of work, age (difference≤5 years) , and working years of noise exposure (difference≤2 years) , according to the criteria of binaural average high-frequency hearing threshold <35 dB, and the speech frequency hearing threshold of any ear at any frequency band ≤25 dB, a total of 584 workers were enrolled as control group. The single nucleotide polymorphisms (SNPs) of rs1695 and rs6591256 in GSTP1 were genotyped by high throughput SNP genotyping assay. Hardy-Weinberg equilibrium of control group was checked. The association between the SNPs at the two loci and susceptibility to NIHL was analyzed. Results: The L(Aeq, 8 h) range of workers exposed to noise was 80.2-98.8 dB (A) . The risk of NIHL in individuals with allele G of rs1695 was 1.291 times of those with allele A (95%CI: 1.042-1.598, P<0.05) . The risk of NIHL in individuals with allele G of rs6591256 was 1.390 times of those with allele A (95%CI: 1.119-1.728, P<0.05) . The risk of NIHL in individuals with AG and GG genotypes of rs6591256 was 1.437 times of those with AA genotype (95%CI: 1.057-1.952, P<0.05) . With the increase of noise exposure duration, individuals with AG and GG genotypes of rs6591256 had a higher risk of NIHL than those with AA genotype (HR=1.273, 95%CI: 1.002-1.616, P<0.05) . Conclusion: The allele G of rs1695 and rs6591256 may be risk factors of NIHL.

[Determination of nitrogen oxides in the air of workplace by ion chromatography]

Objective: Improvement the method of nitrogen oxide sampling, analysis and detection in workplace air. Methods: Absorption and collection with sodium carbonate-sodium bicarbonate buffer solution, analysised by ion chromatography, anion column AS23, column temperature 30 ℃. Results: The linearity of the nitrite ion in the corresponding mass concentration range 0~90.0 μg/ml was good (Nitrogen dioxide in 0~120.0 mg/m(3)) , correlation coefficient>0.999 5. The detection limit was 0.16 μg/ml, The minimum detection concentration was 0.11 mg/m(3) with the sampling volume 7.5 L. Conclusion: The method has good accuracy, high sensitivity, with directing injection and no pre-treatment, and can popularize in general laboratories, and can satisfy the determination of nitrogen oxides in the air of workplace.

[Study on safety of adjuvant radiotherapy concurrent with weekly chemotherapy for stage ⅡB-ⅣA esophageal carcinoma after radical resection]

Objective: To evaluate the tolerability and short-term efficacy of chemo-radiotherapy in 125 patients with stage ⅡB-ⅣA esophageal carcinoma after radical resection. Methods: We retrospectively evaluated the rate of completion, toxicity and survival of patients undergoing adjuvant concurrent chemo-radiotherapy after radical resection of esophageal carcinoma from January 2004 to December 2014 in our institution. The survival rate was determined by the Kaplan-Meier method and analyzed using the log-rank test. Multivariate prognostic analysis was performed using the Cox proportional hazard model. Results: 122 patients received more than 50 Gy dose (97.6%). A total of 52 patients received more than 5 weeks chemo-radiotherapy (41.6%), while 73 patients underwent only 1-4 weeks (58.4%). The median following up was 48.4 months. 8 patients lost follow up (6.4%). The 1-year and 3-year overall survival rate were 91.6% and 57.0%, respectively, with a median survival time of 64.4 months. The 1-year and 3-year disease free survival rate were 73.2% and 54.3%, respectively, with a median disease free survival time of 59.1 months. The most common acute complications associated with chemo-radiotherapy were myelosuppression, radiation esophagitis and radiation dermatitis, the majority of which were Grade 1-2. Of the 125 patients, there were 59 cases of recurrence, including 23 cases with local regional recurrence, 26 cases with hematogenous metastasis, and 8 cases with mixed recurrence. Univariate analysis showed that the numbers of concurrent chemotherapy was associated with the overall survival (P=0.006). But receiving more than 5 weeks was not the prognostic factor compared to 1 to 4 weeks chemotherapy (P=0.231). Multivariate analysis showed that only the numbers of concurrent chemotherapy was an independent prognostic factor (P=0.010). Conclusions: Postoperative radiotherapy concurrent with weekly chemotherapy could improve the overall survival and decrease the recurrence for stage ⅡB-ⅣA esophageal carcinoma after radical resection. However, the completion rate of chemotherapy was low, so it was necessary to explore reasonable regimens to improve the completion rate and carry out prospective randomized controlled trial.

[Expression and clinical significance of SSH1 in gastrointestinal stromal tumors]

Objective: To investigate the correlations between the expression of the slingshot-1(SSH1) and the general clinicopathological factors in gastrointestinal stromal tumor (GIST) patients. Methods: Immunohistochemical staining was used to detect the expression of SSH1 protein in 96 gastrointestinal stromal tumors, and the correlations between expression level of SSH1 and general clinicopathological factors were analyzed. Results: Totally, there were 96 cases of GIST patients (49 males and 47 males), with a mean age of (55.80±12.33) years. The tumors were located in different organs: 62 cases (64.6%) in the stomach, 29 cases (30.2%) in the intestine, and 5 cases (5.2%) in other organs, with a mean tumor size of (5.11±3.73) cm. The low risk group contained 57 cases (59.4%), 18 cases (18.8%) in middle risk group and 21 cases (21.9%) in high risk group. The pathological examination showed that the positive expression rate of CD117, CD34, DOG-1, Ki-67, SMA, S-100 and Desmin was 85.4%, 84.4%, 86.5%, 90.6%, 10.4%, 3.1% and 2.1%, respectively. In 96 cases of GIST, 37 cases (38.5%) had high expression of SSH1, and SSH1 expression level was correlated with the tumor invasion depth, risk classification, tumor mitotic figure count, CD34(+) (P<0.05). Conclusions: SSH1 plays an important role in the development of GIST. High expression of SSH1 is closely related to the invasion depth, risk classification and tumor mitosis of GIST.

[Self-esteem and Occupational Stress Relationship Analysis of 1413 Train Drivers in a Railway Bureau]

Objective: To investigate self-esteem status of train drivers. Methods: By using cluster sampling method, a cross-sectional study was conducted in 1 413 train drivers (including passenger train drivers 301, freight train drivers683, passenger shunting train drivers350, and high speed train drivers79) from a railway bureau. The occupational stressors, strains, self-esteem and personalities were measured using occupational stress instruments and effort-reward imbalance questionnaire. Results: The level of self-esteem is medium ofthe train drivers. Sself-esteem scores among different among different job category (job title) , marry status, age, length of service groups were statistical significance (P<0.01) . Differences of self-esteem among different educational level, exercise, smoking and drinking groups weren't statistical significance (P>0.05) . Correlation analysis revealed that self-esteem score was related positively to job satisfaction (r=0.300) , reward (r=0.842) , working stability (r=0.243) , promotion opportunities (r=0.493) , positive affectivity (r=0.216) , responsibility for human beings (r=0.112) and responsibility for things scores (r=0.108) (P<0.01) , negatively to sleep quality (r=-0.103) , social support (r=-0.212) , role conflict (r=-0.007) , role ambiguity (r=-0.169) , physiological needs (r=-0.115) , daily stress (r=-0.150) , negative affectivity (r=-0.252) , depressive symptoms scores (r=-0.215) (P<0.01) . Nonparametric test found that train drivers of group with low self-esteem score reported higher scores for physiological need, role conflict, role ambiguity, social sleep quality, depressive symptoms, negative affectivity, social support and daily stress scores than the medium and higher groups (P<0.01 or<0.05) . But reword, job satisfaction, positive affectivity, copping stratgy, working stability and promotion opportunities scores were lower than the group of medium and higher groups (P<0.01) . Inter-group conflict scores were insignificance (P>0.05) . Multivariate logistic regression analysis revealed that low low self-esteem for drivers occured the risk of job dissatisfaction about 1.5 times as high as that of drivers with higher self-esteem (OR=1.476) Conclusion: Different types of locomotive drivers get different level of self-esteem. Self-esteem was affected by occupational stress largely.

[Determination of p-Anisidine in workplace air by HPLC]

Objective: To establish an HPLC method for determining p-Anisidine in workplace air. Methods: An C(18) capillary column was used with the detection wavelength of 240 nm, the methanol solution (v/v=62:38) as mobile phase, the flow rate was 0.9 ml/min, and the injection volume was 20 μl. Results: The linear range (μg/ml) for p-Anisidine was 0~100; correlation coefficient was 0.999 7; the detection limit was 0.15 μg/ml; the average precision of RSD was 4.4%. The sampling efficiency was more than 95% using silicone tube as sampling filter. Sample can be stored at room temperature for more than 7 d. Conclusion: the method appered to be accurate, simple, sensitive and reliable, also have a high sampling efficiency, and can be usd to determine p-anisidine in workplace air simultaneously.

[Sleep quality and occupational stress relationship analysis of 1413 train drivers in a railway bureau]

Objective: To investigate sleep quality status of train drivers. Methods: By using cluster sampling method, a cross-sectional study was conducted in 1413 train drivers (including passenger train drivers 301, freight train drivers 683, passenger shunting train drivers 350, and high speed train drivers 79) from a railway bureau. The occupational stressors, strains, personalities and sleep quality were measured using occupational stress instruments and effort-reward imbalance questionnaire. Results: The train drivers of poor sleep quality was 48.34%. Sleep quality scores among different among different job category (job title) , exercise, smoking and drinking were statistical significance (P<0.01) . Differences of sleep quality among different educational level, marry status, age, length of service groups weren't statistical significance (P>0.05) . Correlation: analysis revealed that sleep quality score was related negatively to job satisfaction, reward, working stability, promotion opportunities, positive affectivity, esteem and self-esteem scores (r: -0.454, -0.207, -0.329,-0.170, -0.291, -0.103, -0.139, P<0.01 or P<0.05) , positively to social support, effort, role conflict, conflict between groups, conflict in groups, responsibility for person, responsibility for thing, psychological needs, physiological needs, daily stress, negative affectivity, depressive symptoms scores (r: 0.338, 0.524, 0.226, 0.094, 0.182, 0.210, 0.247, 0.190, 0.615, 0.550, 0.345, 0.570, P<0.01) . Nonparametric test found that train drivers of group with high sleep quality score reported higher scores for physiological need, psychological need, effort, role conflict, conflict between groups, social support, daily stress, depressive symptoms, responsibility for person, responsibility for thing, negative affectivity and coping scores than the group of lower sleep quality score (P<0.01) . But reword, job satisfaction, positive affectivity, self-esteem working stability and Promotion opportunities scores were lower than the group of lower sleep quality score (P<0.01) . Multivariate logistic regression analysis revealed the risk for more physiological needs, more effort, more depressive symptoms and more daily stress for drivers occured the risk of poor sleep quality were more than two times as high as that of drivers with less physiological needs, less effort, less depressive symptoms and less daily stress (OR=2.905~2.005) . Conclusions Different types of locomotive drivers get different level of sleep quality. Sleep quality was affected by occupational stress largely. Reducing the occupational stress may contribute to improve the sleep quality of train drivers.

[Change of occupational stress from 1996 to 2012 among train engine drivers]

Objective: To analyze the change of level of occupational stress between 1996 and 2012 among train engine drivers. Methods: the cross-section investigation was conducted by using cluster sampling method, subjects included 1 116 and 1 002 passenger train engine drivers and freight train engine drivers respectively in 1996 and in 2012;occupational stressors, strains, personalities, buffering factors and individual factors were investigated by using Occupational Stress Instruments. Unconditional logistic regression analyses were performed to estimate the associations between job stressors, personalities, buffering factors and individual factors and strains. Multivariate OR(95%CI) were derived from the logistic regression models. Results: From 1996 to 2012, for the passenger train engine drivers the scores of role ambiguity (17.67±5.30 vs.14.11±4.66) increased 25.32%, mental load (10.41±3.56 vs. 16.29±2.08) and physical environment (3.61±2.18 vs. 7.03±1.65) scores decreased 36.10% and 48.64% respectively, sleep disorders (18.04±9.20 vs. 13.35±4.00) and negative affectivity (2.76±1.86 vs. 2.14±1.86) scores increased 33.14% and 28.97% respectively, the differences were statistical significant (P<0.001) . For the freight train engine drivers the scores of sleep disorders (20.33±8.17 vs. 12.47±4.12) and negative affectivity (2.95±1.70 vs. 1.87±1.81) scores increased 57.75% and 60.03% respectively, positive affectivity (2.17±1.60 vs. 2.91±1.50) score decreased 25.43%, the differences were statistical significant (P<0.001) . In general, scores varies in factors related to occupational stress among freight train engine drivers were larger than those among passenger train engine drivers. The risk factor of job dissatisfaction among passenger train drivers in 1996 was insufficient superior support (OR=3.77, 95%CI: 2.23-6.37) , the risk factors in 2012 were insufficient superior support (OR=3.35, 95%CI:1.56-7.17) , poor physical environment (OR=3.61, 95%CI: 1.91-6.80), and fewer positive affectivity (OR=3.47, 95%CI: 1.75-6.82). The risk factor of job dissatisfaction among freight train drivers in 1996 and in 2012 were insufficient superior support (OR (95%CI) were 3.11 (2.31-4.19), 2.59 (1.84-3.65) , respectively). Conclusion: The level of occupational stress among train engine drivers in 2012 was larger than that in 1996, the level of occupational stress among freight train drivers was larger than passenger train drivers, the interventions aimed at reducing occupational stress in the Chinese train engine drivers should take into account promotion for design of job organization and contents and organization management style.

[Current status of hearing loss and related influencing factors in workers with noise exposure in refining and chemical industry]

Objective: To investigate the current status of hearing loss and related influencing factors in workers with noise exposure in refining and chemical industry. Methods: From August 2015 to March 2016, the investigation method of collecting the data of past occupational health examinations and measuring noise in working environment was used to enroll 8 672 male workers. Results: Of all workers, 11.6% were diagnosed with hearing loss. There were significant differences in the distribution of hearing impairment among workers exposed to noise at different ages, device types and types of work (χ(2)=17.80, 77.80 and 30.53, all P<0.05) . The level of noise exposure≥85 dB (A) (OR=5.79, 95%CI 3.70-8.81) , working years with noise exposure (OR=1.57, 95%CI 1.05-2.43) , and 25 years (OR=3.29, 95%CI 2.08-5.71) were risk factors for hearing loss in workers with noise exposure in refining and chemical industry. Conclusion: The level of noise exposure and working years with noise exposure are main influencing factors for hearing loss in workers with noise exposure in refining and chemical industry.

[Association between single nucleotide polymorphismsin human heat shock protein 70 gene and susceptibility to noise-induced hearing loss]

Objective: To investigate the association between the single nucleotide polymorphisms (SNPs) at rs1043618, rs2075800, and rs2763979 in human heat shock protein 70 (HSP70) gene and susceptibility to noise-induced hearing loss (NIHL) . Methods: A case-control study was performed, and 5 934 workers exposed to noise in an iron and steel plant in Henan, China, who underwent physical examination from 2006 to 2015, were enrolled as study subjects. According to the criteria of binaural average high - frequency (3000, 4000, and 6000 Hz) hearing threshold≥40 dB (HL) and monauralaverage speech-frequency (500, 1000, 2000 Hz) hearing threshold≥26 dB (HL) on the basis of binauralhigh frequency loss measured by pure tone audiometry, as well as the exclusion of NIHL, a total of 286 workers were enrolled as hearing loss group; after the adjustment for sex, type of work, age (difference≤5 years) , and working years of noise exposure (difference ≤2 years) , 286 workers were enrolled as control group. A 2 ml blood genomic DNA extraction kit was used to perform DNA extraction for the peripheral blood samples, and a multiple SNP typing kit was used to determine the genotypes at the three loci in 572 samples. The association between the SNPs at the three loci and susceptibility to NIHL was analyzed. Results: In all workers, the equivalent sound level (L(Aeq)) of noise was 75.0~96.8 dB (A) . The hearing loss group had a significantly higher binauralhigh - frequencyhearing threshold than the control group (t=56.908, P<0.05) . With CC+TC genotype as control, TT genotype at rs2763979 in HSP70 gene was associated with the susceptibility to NIHL (OR=1.731, 95%CI 1.021-2.935) . In the group with cumulative noise exposure of 96 dB (A) ·year, TT genotype at rs2763979was associated with the susceptibility to NIHL (OR=5.694, 95%CI 1.256-25.817) . The rs1043618 and rs2075800 loci of HSP70 were not associated with the susceptibility to NIHL (both P>0.05) . After the adjustment for confounding factors including smoking and drinking, haplotype CCT was associated with the susceptibility to NIHL (OR=1.425, 95%CI 1.035-1.961) . Conclusion: TT genotype at rs2763979 of HSP70 gene and haplotype CCT are risk factors for NIHL.

[Association of etheno-DNA adduct and DNA methylation level among workers exposed to diesel engine exhaust]

Objective: To investigate the association between etheno-DNA adduct and the promoter of DNA methylation levels of cyclin dependent kinase inhibitor 2A (P16), Ras association domain family 1 (RASSF1A) and O-6-methylguanine-DNA methyltransferase (MGMT) in workers with occupational exposure to diesel engine exhaust (DEE). Methods: We recruited 124 diesel engine testing workers as DEE exposure group and 112 water pump operator in the same area as control group in Henan province in 2012 using cluster sampling. The demographic data were obtained by questionnaire survey; urine after work and venous blood samples were collected from each subject. The urinary etheno-DNA adducts were detected using UPLC-MS/MS, including 1,N6-etheno-2'-deoxyadenosine (εdA) and 3,N4-etheno-2'-deoxycytidine(εdC). The DNA methylation levels of P16, RASSF1A, and MGMT were evaluated using bisulfite-pyrosequencing assay. The percentage of methylation was expressed as the 5-methylcytosine (5mC) over the sum of cytosines (%5mC). Spearman correlation and multiple linear regression were applied to analyze the association between etheno-DNA adducts and DNA methylation of P16, RASSF1A, and MGMT. Results: The median (P(25)-P(75)) of urinary εdA level was 230.00 (98.04-470.91) pmol/g creatinine in DEE exposure group, and 102.10 (49.95-194.48) creatinine in control group. The level of εdA was higher in DEE exposure group than control group (P<0.001). DNA methylation levels of P16, RASSF1A and MGMT were 2.04±0.41, 2.19 (1.94-2.51), 2.22 (1.94-2.46)%5mC in exposure group, and 2.19±0.40, 2.41 (2.11-2.67), 2.44 (2.15-2.91)%5mC in control group. DNA methylation levels were lower in exposure group (P values were 0.005, 0.002 and 0.001, respectively). Spearman correlation analysis showed that DNA methylation levels of P16, RASSF1A, and MGMT were negative associated with urinary εdA level (r values were -0.155, -0.137, and -0.198, respectively, P<0.05). No significant correlation was observed between the εdC level and any measured DNA methylation levels (P>0.05) . Multiple linear regression confirmed the negative correlation between εdA and DNA methylation levels of P16, RASSF1A, and MGMT in non-smoking group (β (95%CI) was -0.068 (-0.132--0.003), -0.082 (-0.159--0.004) and -0.048 (-0.090--0.007), P values were 0.039, 0.039 and 0.024, respectively). Moreover, εdC was negative associated with DNA methylation level of MGMT in non-smoking group (β (95%CI) was -0.094 (-0.179--0.008), P=0.032). Conclusion: DEE exposure could induce the increased of εdA and decreased of DNA methylation levels of P16, RASSF1A and MGMT.

[A cohort study on occupational noise induced hearing loss in workers at an iron and steel plant]

Objective: To analyze the incidence rate of occupational noise-induced hearing loss in noise-exposed workers in an iron and steel plant from 2006 to 2015. Methods: Using a cohort study method, workers exposed to occupational noise from Jan 1, 2006 to Dec 12, 2015 were followed up and the pure tone hearing test was conducted. In total, 6 297 subjects completed two or more physical checks and the pure tone hearing test and were included in the analysis. The noise exposure level at the workplace and the equivalent continuous A-weighted sound pressure level for workers was monitored and the cumulative noise exposure dose was evaluated. The subjects were divided into low, middle and high exposure groups according to the noise exposure level, and the equivalent continuous A-weighted sound pressure level for 8 hours for each group was 80.6-85.0, 85.1-90.0 and 90.1-103.4 dB (A), respectively. While the RR and 95% CI were derived from unconditional logistic regression models. In logistic regression analysis, confounding factors such as age, gender, smoking habit, drinking habit, high temperature exposure and chemical hazards exposure level were controlled. Results: During the follow-up period, 392 cases of occupational noise-induced hearing loss were diagnosed among the 6 297 subjects, with an incidence rate of 6.23%; 318 cases of high-frequency hearing loss were diagnosed, with an incidence rate of 5.05%; and 74 cases of occupational noise-induced deafness were diagnosed, with an incidence rate of 1.18% . The incidence rates of hearing loss among the high, medium and low exposure groups were 9.22% (158/1 737), 6.49% (204/3 142) and 2.08% (30/1 442), respectively; the rates of high-frequency hearing loss were 7.41% (127/1 737), 5.25% (165/3 142) and 1.80% (26/1 442), respectively; and the rates of occupational noise-induced deafness were 1.81% (31/1 737), 1.24% (39/3 142) and 0.28% (4/1 442), respectively. For the groups corresponding to cumulative noise exposure doses of ≤84.99, 85.00- 87.99, 88.00- 90.99, 91.00- 93.99, 94.00- 96.99, 97.00- 100.99, 101.00- 102.99 and ≥103.00 dB (A) · year, the incidence rates of hearing loss were 0 (0/185), 1.22% (2/164), 2.52% (17/674), 3.83% (35/913), 5.80% (106/1 827), 6.02% (67/1 113), 9.20% (95/1 003) and 18.04% (70/388), respectively. Compared with the low exposure group, the RR of hearing loss, high-frequency hearing loss and occupational noise-induced deafness for the high exposure group were 4.78 (95% CI: 3.22- 7.11), 4.36 (95% CI: 2.84- 6.69) and 6.63 (95% CI: 2.33- 18.82), respectively; and for the medium exposure group were 3.27 (95% CI: 2.22-4.82), 3.02 (95% CI: 1.99-4.59) and 4.52 (95% CI: 1.61-12.67), respectively. Conclusion: The incidence rate of hearing loss for workers exposed to noise in an iron and steel plant was related to the cumulative noise exposure dose, gender, age, educational level, smoking habits, drinking habits and exposure to high temperature.

[Effects of simvastatin on the proliferation, invasion and radiosensitivity in Lewis lung cancer cell line]

Objective: To investigate the effects of simvastatin on proliferation, invasion and radiosensitivity of mouse Lewis lung cancer cell line in vitro. Methods: The inhibitory effects of simvastatin on proliferation of Lewis lung cancer cells were detected by MTT assay. Matrigel invasion and migration assay was used to determine the invasion and motility ability of the Lewis cells. P38 activity was measured by p38 activity detection kit, and the expressions of p-p38, MKP-1, RhoA and MMP-2 were analyzed by Western blot. Lung cancer xenograft model was established in C57BL/6 mice. The mice were randomly divided into control group, simvastatin group, radiotherapy alone group and combined treatment group. The mice were killed 27 days after inoculation. The tumor mass, volume and lung metastatic nodules in the mice were compared. Results: The cell proliferation rates of 0 μmol/L, 10 μmol/L, 20 μmol/L and 30 μmol/L simvastatin groups were 100%, (87.0±9.0)%, (76.5±8.1)% and (67.0±7.3)%, respectively (P<0.05). Invasive cell numbers of the above groups were 298±30, 251±26, 207±20 and 132±19 per field, respectively (P<0.05). The intracellular p38 activities were 100%, (83.1±8.8)%, (70.2±8.2)% and (59.0±6.4)%, respectively. The relative expressions of p-p38 were 100%, (76.2±6.7)%, (56.4±5.4)% and (36.5±3.2)%, respectively. The expressions of RhoA were 100%, (80.1±5.3)%, (55.3±6.2)% and (38.6±4.8)%, respectively. The expressions of MMP-2 were 100%, (89.6±8.6)%, (51.9±4.7)% and (42.7±3.1)%, respectively, while the expressions of MKP-1 were 100%, (136.5±12.2)%, (168.8±15.3)% and (187.7±13.4)%, respectively (all P<0.05). Lung metastatic nodules and mass in the control, simvastatin, radiotherapy group and combined treatment groups were 6.24±1.09, 3.07±0.71 g, 5.09±1.16, 2.43±0.53 g, 3.12±0.68, 1.96±0.62 g and 2.65±0.38, 1.12±0.43 g, respectively (all P<0.05). The tumor inhibition rates were 39.0%, 48.1% and 26.5%, respectively, in the radiotherapy alone, combined treatment and simvastatin groups (all P<0.05). Conclusions: Simvastatin inhibits the proliferation of Lewis cell line by inhibiting the activity of p38 and expression of p-p38. Meanwhile, simvastatin reduces the invasion and motility of Lewis cell line through down-regulating the expression of RhoA and MMP-2. When combined with radiotherapy, simvastatin can inhibit tumor growth and metastasis, and improve the treatment efficacy of radiotherapy synergistically.

[Mediating role of over-commitment in the relationship between effort, reward and burnout]

Objective: To explore the mediating role of over-commitment in the relationship between occupational stressors and job burnout, and to offer more specificevidence-based information in exploring the work related health effects of over-commitment. Methods: A total of 1994 samples from electronic manufacturing service industry were collected in Guangdong province based on self-rated questionnaire after written consent from June to July, 2015. The Effort-Reward Imbalance questionnaire and Maslach Burnout Invertory-General Survey were used for the measurement of occupational stress and job burnout. And hierarchical regression and Bootstrap test were conducted for data analysis. Results: High effort (0.28, 0.24-0.33) and low reward (-0.37, -0.42--0.33) were significantly associated with high over-commitment when gender, age and position had been controlled. Standardizedregression coefficient of effort to emotional exhaustion, depersonalization and personal accomplishment were 0.63 (95%CI: 0.54-0.71) 、0.18 (95%CI: 0.10-0.26) 、0.32 (95%CI: 0.21-0.43) , P<0.05; and standardized regression coefficient of reward to emotional exhaustion, depersonalization and personal accomplishment were-0.60 (95%CI: -0.68--0.52) 、-0.93 (95%CI: -1.01--0.86) 、-0.46 (95%CI: -0.35--0.58) , P<0.05. Bootstrap test indicated the mediation of over-commitment were statistically significant, and mediating effect ranges from 0.093 to 0.218 (P<0.05) . Conclusion: Over-commitment can mediate the relationship between occupational stressors (job effort and reward) and burnout, and the effect varies from different workingconditions.

[Social support and occupational stress relationship analysis of 1 413 train drivers in a railway bureau]

Objective: To investigate the social support status of train drivers. Methods: Using cluster sampling, a cross-sectional study was conducted in 1 413 male train drivers (including 301 passenger train drivers, 683 freight train drivers, 85 guest scheduling train drivers, 265 cargo adjustable drivers, and 79 high-speed train drivers) from a railway bureau depot. The survey included individual factors, social support, occupational stressors, strains, personalities, and coping strategy using occupational stress instruments and effort-reward imbalance questionnaire. We compared the difference in social support scores between different drivers, who were divided according to job type and age. Additionally, the correlation between social support score and job strain-related factors was analyzed. The influence of depressive symptoms and job satisfaction were analyzed using a non-conditional logistic multivariate model. Results: The overall average age P(50) (P(25),P(75)) of 1 413 train drivers was 33.92 (27.83,43.58) years. The overall average length of service 12.25 (5.25,22.75) years. A significant difference in social support scores was observed according to job type (H=23.23, P<0.001). The specific scores were passenger driver(27 (23,32)), freight train driver (26 (22,30)), guest scheduling driver (27 (24,30)), cargo adjustable driver (26 (22,31)), and high-speed train driver (30 (26,36)) (P(50)(P(25),P(75))). Additionally, social support scores among different age groups were significantly different (H=6.64, P=0.036). The specific scores were ≤30 years (26 (22,31)), 30-40 years (27 (23,33)), and >40 years (27 (22,31)). Correlation analysis revealed that the social support score was negatively associated with job satisfaction (r=-0.43), reward (r=-0.22), working stability (r=-0.23), promotion opportunities (r=-0.12), positive affectivity (r=-0.31), esteem (r=-0.21), and self-esteem (r=-0.20) scores (P<0.001). The social support score was positively associated with sleep disorders (r=0.33), external effort (r=0.21), pay within (r=0.12), role conflict (r=0.20), conflict between groups (r=0.17), conflict in groups (r=0.06), responsibility for the others (r=0.06), responsibility for things (r=0.08), physiological needs (r=0.39), psychological needs (r=0.19), daily stress (r=0.29), negative affectivity (r=0.23), and depressive symptoms (r=0.44) scores (P<0.05). Multivariate logistic regression analysis revealed social support had a great influence on depressive symptoms and low job satisfaction. Compared with high social support, low social support resulted in depressive symptoms (OR=4.12, 95% CI:3.19-5.33) and low job satisfaction (OR=2.18, 95%CI:1.65-2.88). Conclusion: Train drivers obtained various levels of social support. Social support greatly affected occupational stress. High social support was related to reduction in the occurrence of occupational stress, depressive symptoms, and low job satisfaction. Social support is related to mental health of train drivers.

[Influencing factors for job satisfaction in train drivers in a railway bureau: an analysis of 1413 cases]

Objective: To investigate the influencing factors for job satisfaction in train drivers. Methods: In March 2012, cluster sampling was used to conduct a cross-sectional survey in 1413 male train drivers (including 301 passenger train drivers, 683 freight train drivers, 350 passenger shunting train drivers, and 79 high-speed train drivers) from a locomotive depot of a railway bureau. The occupational stress instruments, job content questionnaire, and effort-reward imbalance questionnaire were used to analyze job satisfaction, occupational stress factors, stress reaction, individual characteristics, coping strategies, and social support. Results: There were significant differences in job satisfaction score between the drivers with different posts, working years, ages, smoking status, and drinking status (P<0.01). The correlation analysis revealed that job satisfaction score was positively correlated with reward, working stability, promotion opportunity, positive emotion, social support, self-esteem, and coping strategy scores (P<0.01) and negatively correlated with sleep disorders, effort, role conflict, intergroup conflict, responsibility for persons, responsibility for things, psychological needs, physiological needs, daily stress, negative emotion, and depressive symptom scores (P< 0.01). The analysis of variance showed that compared with the moderate and low job satisfaction groups, the high job satisfaction group had significantly higher reward, positive emotion, promotion opportunity, and role ambiguity scores (P<0.01) , as well as significantly lower scores of responsibility for persons and responsibility for things (P<0.01). Compared with the moderate and high job satisfaction groups the low job satisfaction group had significantly higher scores of psychological needs, effort, role conflict, sleep disorders, daily stress, depressive symptom, negative emotion, drug use, intragroup conflict, and social support (P<0.01) , and the moderate job satisfaction group had a significantly higher score of self-esteem than the other two groups (P<0.05). The logistic regression analysis showed that the risk of job dissatisfaction in the drivers with low so-cial support and high daily stress was more than 2 times that in those with high social support and low daily stress (OR=2.176 and 2.171) , and sleep disorders, effort, depressive symptom, low self-esteem, and role conflict were risk factors for job dissatisfaction (OR=1.48-1.625). Conclusion: Occupational stress, stress re-sponse, emotion, individual characteristics, and social support have great influence on job satisfaction. Im-proving social support, increasing positive emotion, and reducing occupational stress are main measures for increasing job satisfaction in train drivers.

[Investigation into the relationship between mitochondrial 12 S rRNA gene, tRNA gene and cytochrome oxidase Ⅱ gene variations and the risk of noise-induced hearing loss]

Objective: To explore the relationship between mitochondrial 12 S rRNA gene variation, tRNA gene variation and cytochrome oxidase Ⅱ gene point mutations and the risk of noise-induced hearing loss (NIHL). Methods: A nested case-control study was performed that followed a cohort of 7 445 noise-exposed workers in a steel factory in Henan province, China, from January 1, 2006 to December 31, 2015. Subjects whose average hearing threshold was more than 40 dB(A) in high frequency were defined as the case group, and subjects whose average hearing threshold was less than 35 dB(A) in high frequency and less than 25 dB (A) in speech frequency were defined as the control group. Subjects was recruited into the case group (n=286) and the control group (n=286) according to gender, age, job category and time of exposure to noise, and a 1∶1 case-control study was carried out. We genotyped eight single nucleotide polymorphisms in the mitochondrial 12 S rRNA gene, the mitochondrial tRNA gene and the mitochondrial cytochrome oxidase Ⅱ gene using SNPscan high-throughput genotyping technology from the recruited subjects. The relationship between polymorphic sites and NIHL, adjusted for covariates, was analyzed using conditional logistic regression analysis, as were the subgroup data. Results: The average age of the recruited subjects was (40.3±8.1) years and the length of service exposure to noise was (18.6±8.9) years. The range of noise exposed levels and cumulative noise exposure (CNE) was 80.1- 93.4 dB (A) and 86.8- 107.9 dB (A) · year, respectively. For workers exposed to noise at a CNE level<98 dB (A) · year, smokers showed an increased risk of NIHL of 1.88 (1.16-3.05) compared with non-smokers; for workers exposed to noise at a CNE level ≥98 dB(A) · year, smokers showed an increased risk of NIHL of 2.53 (1.49- 4.30) compared with non-smokers. For workers exposed to noise at a CNE level<98 dB (A) · year, the results of univariate analysis and multifactor analysis, adjusted by smoking and CNE, suggested that the risk of NIHL in workers exposed to noise carrying the GG genotype (G827A) was lower than that of NIHL workers exposed to noise carrying the AA genotype (G827A) [OR (95% CI) were 0.18 (0.04- 0.82) and 0.19 (0.04- 0.88), respectively]. Conclusion: Smoking increased the risk of NIHL in the present study. For workers subjected to a CNE<98 dB(A)·year, the mitochondrial genetic variant G827A was found to be significantly associated with the risk of NIHL.

Quasi mode-locking of coherent feedback random fiber laser

Mode-locking is a milestone in the history of lasers that allows the generation of short light pulses and stabilization of lasers. This phenomenon is known to occur only in standard ordered lasers for long time and until recently it is found that it also occurs in disordered random lasers formed by nanoscale particles. Here, we report the realization of a so-called quasi mode-locking of coherent feedback random fiber laser which consists of a partially disordered linear cavity formed between a point reflector and a random distributed fiber Bragg grating array with an inserted graphene saturable absorber. We show that multi-groups of regular light pulses/sub-pulses with different repetition frequencies are generated within the quasi mode-locking regime through the so-called collective resonances phenomenon in such a random fiber laser. This work may provide a platform to study mode locking as well as pulse dynamic regulation of random lasing emission of coherent feedback disordered structures and pave the way to the development of novel multi-frequency pulse fiber lasers with potentially wide frequency tuning range.

[Influencing factors for hearing loss in workers exposed to noise in a cement plant]

Objective: To investigate the incidence of noise-induced hearing loss (NIHL) and related influencing factors in workers exposed to noise in a cement plant. Methods: In October 2015, cluster sampling was used for questionnaire investigation and health examination of workers exposed to noise in a cement plant in Henan Province, China. The association of demographic features, living habits, cumulative noise exposure (CNE) , hypertension, and hyperlipidemia with NIHL was analyzed. Results: There was mainly medium-or high-frequency noise in the working place of this cement plant. The prevalence rate of NIHL was 18.4%, and male workers had a significantly higher prevalence rate than female workers (χ(2)=28.09, P<0.01) . The prevalence rate of NIHL increased with the increasing age (χ(2trend)=25.54, P<0.01) and decreasedwith the increasing degree of education (χ(2trend)=8.55, P<0.01) . The workers who smoked had a significantly higher prevalence rate of NIHL than those who did not smoke (χ(2)=14.15, P<0.01) , and the workers with a drinking habit had a significantly higher prevalence rate of NIHL than those without such habit (χ(2)=7.95, P<0.01) . The workers who did not wear earplugs had a significantly higher prevalence rate of NIHL than those who wore earplugs (χ(2)=19.93, P<0.01) . The prevalence rate of NIHL increased with the increasing CNE (χ(2trend)=57.81, P<0.01) . The workers with hyperlipidemiahad a significantly higher prevalence rate of NIHL than those without hyperlipidemia (χ(2)=12.43, P<0.01) . The multivariate logistic regression analysis showed that male sex (OR=5.06, 95%CI 1.68-15.26) , age ≥50 years (OR=1.91, 95%CI 1.12-3.27) , CNE 97.01-103 dB (A) ·year (OR=16.10, 95%CI 4.65-55.69) , CNE 103.01-118.37dB (A) ·year (OR=20.27, 95%CI 5.14-79.92) , and hyperlipidemia (OR=2.83, 95%CI 1.25-6.43) were risk factors for NIHL, while high school education (OR=0.22, 95%CI 0.09-0.56) , junior college diploma (OR=0.16, 95%CI 0.41-0.59) , and use of earplugs (OR=0.36, 95%CI 0.19~0.71) were protective factors against NIHL. Conclusion: The workers in a cement plant have a high prevalence rate of NIHL, and CNE, sex, age, degree of education, use of earplugs, and hyperlipidemia may be influencing factors for NIHL.

[Association between CDH23 gene polymorphisms and susceptibility to noise-induced hearing loss in the Chinese population: a meta-analysis]

Objective: To investigate the association between cadherin-23 (CDH23) gene polymorphisms and susceptibility to noise-induced hearing loss (NIHL) in the Chinese population through a meta-analysis. Methods: In June 2016, CNKI, VIP, Wanfang Data, and PubMed were searched for studies on the association between CDH23 gene polymorphisms and susceptibility to NIHL in the Chinese population. The articles were screened according to inclusion and exclusion criteria and related data were extracted. RevMan 5.3 was used for the meta-analysis. Results: A total of three Chinese articles were included. For CDH23-rs1227049, the risk of NIHL in people with C allele was 0.82 times (95%CI 0.39-1.73) that in people with G allele, the risk of NIHL in people with CG+CC genotype in the dominant model was 0.70 times (95%CI 0.34-1.43) that in people with GG genotype, the risk of NIHL in people with CC genotype in the recessive model was 1.23 times (95%CI 0.28-5.43) that in people with CG+GG genotype, and the risk of NIHL in people with CC genotype in the additive model was 1.05 times (95%CI 0.20-5.44) that in people with GG genotype (all P>0.05) . For CDH23-rs1227051, the risk of NIHL in people with T allele was 0.98 times (95%CI 0.71-1.37) that in people with C allele, and the risk of NIHL in people with CT+CC genotype in the dominant model was 1.09 times (95%CI 0.75-1.57) that in patients with TT genotype (both P>0.05) . Conclusion: There is still no enough evidence for the determination of CDH23-rs1227049 and CDH23-rs1227051 to be the susceptibility gene loci of NIHL.

[Influence of occupational stress and 5-hydroxytryptamine 2A receptor gene polymorphisms on depression in workers in a thermal power plant]

Objective: To investigate the association of occupational stress and 5-hydroxytryptamine 2A (5-HT2A) receptor gene polymorphisms with depression. Methods: In November 2010, cluster sampling was used to select 589 workers in a thermal power plant as study subjects. Questionnaires were used to investigate demographic features and occupational stressors. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the genotypes of T102C and A-1438G in 5-HT2A receptor gene in 589 workers. Results: High-level daily hassles (OR=3.013, 95%CI 1.642~5.530) , more negative emotion (OR=4.808, 95% CI 2.662~8.681) , more body needs (OR=1.890, 95% CI 1.034~3.453) , and severe role conflict (OR=1.815, 95% CI 1.002~3.288) were risk factors for depression, while high rewards (OR=0.424, 95% CI 0.226~0.796) was the protective factor against depression (all P<0.05). There were no significant differences in T102C genotype and allele distributions between the groups with and without depression (P>0.05) ; there was a significant difference in A-1438G genotype distribution between the groups with and without depression (χ²= 9.573, P<0.05) , while there was no significant difference in A-1438G allele distribution between these groups (P>0.05). The risk of depression in the workers with high-level daily hassles who carried TC genotype (OR= 4.473, 95% CI 1.161~17.238) or CC genotype (OR=5.176, 95% CI 1.367~19.593) of T102C was 4.473 and 5.176 times that in those with low-level daily hassles who carried TT genotype, and the risk of depression in the workers with more negative emotions who carried TC genotype (OR=5.667, 95%CI 1.204~26.673) or CC genotype (OR=8.114, 95% CI 1.747~37.677) of T102C was 5.667 and 8.114 times that in those with less negative emotion who carried TT genotype. The risk of depression in the workers with high-level daily hassles who carried AG genotype (OR=4.505, 95% CI 2.215~9.162) or GG genotype (OR=6.484, 95% CI 2.562~ 16.414) of A-1438G was 4.505 and 6.484 times that in those with low-level daily hassles who carried AA genotype, and the risk of depression in the workers with more negative emotion who carried AG genotype (OR= 4.877, 95%CI 2.326~10.223) or GG genotype (OR=9.090, 95%CI 3.491~23.673) of A-1438G was 4.877 and 9.090 times that in those with less negative emotion who carried AA genotype. The risk of depression in the workers with higher rewards who carried AG genotype (OR=0.152, 95%CI 0.074~0.310) or GG genotype (OR= 0.384, 95% CI 0.153~0.964) of A-1438G was 0.152 and 0.384 times that in those with lower rewards who carried AA genotype. Conclusion: Occupational stress is associated with the development of depression and interacts with 5-HT2A receptor gene polymorphisms.

[Association between grainyhead-like 2 gene polymorphisms and noise-induced hearing loss]

OBJECTIVE

To investigate association between genetic polymorphism in the grainyhead-like 2 gene (GRHL2) and noise-induced hearing loss (NIHL) in the Chinese population.

METHODS

A matched case-control association study was employed, In which, 3 790 workers exposed to continuous and steady-state occupational noise in a steel factory participated. The questionnaires were adopted to collect individual features and audiometry tests performed. In the sstudy, 286 subjects were diagnosed as cases, Which were each designated on the basis of the matched criterion, and 286 paired samples were selected finally. Noise intensity was measured according to the standards given in 'Measurement of Noise in the Workplace'(Occupational Health Standard of the People's Republic of China, GBZ/T189.8-2007). Cumulative noise exposure (CNE) was calculated, according to monitoring data on A-weighed sound pressure level and employment time. Genomic DNA was obtained from peripheral blood samples using 2 mL DNA extraction Kit following the manufacturer's protocol. Five single nucleotide polymorphisms (SNPs) of GRHL2 were genotyped by multiplex SNP genotyping kit. The continuous variables and categorical variables were analyzed by t-test and chi-square test respectively. Multivariate Logistic regression was used to test the association between genetic frequency and disease status, with adjustments for the possible confounding variables. The haplotypes were established and their frequencies in the two groups were assessed by haploview and phase softwares.

RESULTS

All the five SNPs (rs3735713, rs3824090, rs3735714, rs3735715 and rs611419) were in Hardy-Weinberg equilibrium (HWE) (P>0.05). The subjects carrying rs3735715 GG genotype had a higher NIHL risk than those carrying the GA genotype under the co-dominant model (OR=0.644, 95% CI: 0.442-0.939, P=0.022) after adjustment for height, blood pressure, drinking status and smoking status. After being stratified by CNE, in the CNE ≥ 98 dB (A) group, rs3735715 polymorphism was associated with the NIHL under the co-dominant model (OR=0.509, 95% CI: 0.281-0.923, P=0.026) after adjustment for height, blood pressure, drinking status and smoking status as well. However, no statistical significant difference was found in variant genotypes of the other SNPs between the case and control subjects. Four-locus (rs3735713, rs3824090, rs3735714 and rs3735715) haplotypes were constructed, and no risk or protective haplotypes was identified.

CONCLUSION

It is suggested that GRHL2 polymorphisms may be associated with development of NIHL.

[Factors influencing electrocardiogram results in workers exposed to noise in steel-making and steel-rolling workshops of an iron and steel plant]

OBJECTIVE

To investigate the factors influencing the electrocardiogram results in the workers exposed to noise in steel-making and steel rolling workshops of an iron and steel plant.

METHODS

From September to December, 2013, cluster sampling was used to select 3 150 workers exposed to noise in the steel-making and steel-rolling workshops of an iron and steel plant, and a questionnaire survey and physical examinations were performed. The number of valid workers was 2 915, consisting of 1 606 workers in the steel-rolling workshop and 1 309 in the steel-making workshop. The electrocardiogram results of the workers in steel-making and steel-rolling workshops were analyzed.

RESULTS

The overall abnormal rate of electrocardiogram was 26.35%, and the workers in the steel-making workshop had a significantly higher abnormal rate of electrocardiogram than those in the steel-rolling workshop(32.24% vs 21.54%, P<0.05). Male workers had a significantly higher abnormal rate of electrocardiogram than female workers(27.59% vs 18.61%, P<0.05). The workers with a drinking habit had a significantly higher abnormal rate of electrocardiogram than those who did not drink(28.17% vs 23.75%, P<0.05). The workers exposed to high temperature had a significantly higher abnormal rate of electrocardiogram than those who were not exposed to high temperature(29.43% vs 20.14%, P<0.05). The abnormal rates of electrocardiogram in the workers with cumulative noise exposure levels of <90, 90~94, 95~99, 100~104, and 105~113 dB(A)·year were 21.21%, 21.76%, 26.50%, 27.27%, and 32.16%, respectively, with significant differences between any two groups(P<0.05). The multivariate logistic regression analysis showed that a cumulative noise exposure of 105-113 dB(A)·year(OR=1.36, 95% CI: 1.03~1.80), a drinking habit(OR=1.20, 95% CI: 1.01~1.43), and high temperature(OR=1.60, 95% CI: 1.32~1.92) were the risk factors for abnormal electrocardiogram results.

CONCLUSION

High cumulative noise exposure, alcohol consumption, and high temperature may affect the abnormal rate of electrocardiogram in the workers exposed to noise in steel-making and steel-rolling workshops.