Risk Of Noise-induced Hearing Loss Research Articles

The Role of the Kurtosis Metric in Evaluating the Risk of Occupational Hearing Loss Associated with Complex Noise - Zhejiang Province, China, 2010-2019.

What is already known about this topic?Occupational noise-induced hearing loss (NIHL) has been the second most common occupational disease in China. Noise energy is the main risk factor for occupational NIHL. Evidence shows the temporal structure of noise (as indicated by kurtosis metric) contribute to the development of NIHL. However, the role of the kurtosis metric in evaluating the risk of occupational NIHL associated with complex noise has been rarely reported.What is added by this report?Noise temporal structure (as indicated by kurtosis) is an important risk factor for occupational NIHL in addition to noise energy. Kurtosis can be used to quantify complex noise exposure. A combination of noise kurtosis and noise energy can effectively evaluate the risk of occupational hearing loss associated with complex noise.What are the implications for public health practice?Considering the effect of noise temporal structure on occupational NIHL, the existing international noise exposure standards (e.g. measurement method and noise exposure limit) for complex noise should be modified based on noise temporal structure. More effort is needed to reduce noise exposure, improve health screening, and monitor occupational NIHL.

CARD8 polymorphism rs2043211 protects against noise-induced hearing loss by causing the dysfunction of CARD8 protein.

Inflammation is a complicated process and is considered to be responsible for the development of noise-induced hearing loss (NIHL). CARD8 is an important component of inflammasome that has been implicated in inflammation. To decide the relationship between the polymorphisms of CARD8 gene and NIHL risk and deduce the potential mechanism, three SNPs (rs2043211, rs1062808, and rs12459322) were genotyped in a Chinese population consisting of 610 NIHL cases and 612 normal hearing controls. The possible impacts of SNPs on CARD8 structure and function were assessed using a variety of bioinformatics tools. Plasmids expressing wild-type and/or mutated CARD8 were transfected into HEK293 cells to verify the effect of SNPs on CARD8 protein expression level by western blot. The results revealed that rs2043211 AA genotype and A allele were associated with decreased risk of NIHL. Stratified analysis found that the male, drinking and exposed to noise ≥ 92dB, subjects harboring rs2043211 A allele had a low risk of NIHL. The haplotype AGG (rs2043211-rs1062808-rs12459322) was significantly associated with a decreased risk of NIHL. SNP rs2043211 was predicted to be deleterious and affects CARD8 protein structure and stability. Furthermore, the functional experiment showed the mutant CARD8 could significantly decrease the CARD8 protein expression level. This study confirms that rs2043211 A allele may reduce NIHL risk by causing the loss of PPI combined with the decreased CARD8 expression level leading to CARD8 functional changes, and it may be one valuable genetic biomarker of NIHL susceptibility for Chinese noise-exposed workers.

New trends in the prevention of occupational noise-induced hearing loss.

Noise exposure during lifespan is one of the main causes of hearing loss. The highest risk of noise-induced hearing loss (NIHL) is related to exposures in the workplace, and affects about 7% of the population. Occupational NIHL is irreversible, thus its prevention must be considered a priority. Although current hearing conservation programs (HCPs) have proved to be very beneficial, the incidence of occupational NIHL is still high, reaching about 18% of overexposed workers. This paper reviews recent research on the effects of noise on hearing in pursuit of more effective methods for the prevention of occupational NIHL. The paper discusses the translational significance of noise-induced cochlear neuropathy, as recently shown in animals, and the concept of hidden hearing loss in relation to current NIHL damage risk criteria. The anticipated advantages of monitoring the incidents of the temporary threshold shift (TTS) in workers exposed to high levels of noise have been analyzed in regard to the preclinical diagnostics of NIHL, i.e., at the stage when hearing loss is still reversible. The challenges, such as introducing speech-in-noise audiometry and TTS computational predictive models into HCPs, have been discussed. Finally, the paper underscores the need to develop personalized medical guidelines for the prevention of NIHL and to account for several NIHL risk factors other than these included in the ISO 1999:2013 model. Implementing the steps mentioned above would presumably further reduce the incidence of occupational NIHL, as well as associated social costs. Int J Occup Med Environ Health. 2020;33(6):841-8.

Association between single nucleotides polymorphism of catalase gene and susceptibility to noise-induced hearing loss in occupational population

To investigate the relationship between single nucleotides polymorphism of catalase(CAT) gene and susceptibility to noise-induced hearing loss(NIHL) in occupational noise exposed population. A case-control study of 1∶1 was conducted to select 286 workers with binaural high frequency average hearing threshold ≥40 dB(HL), from 2006 to 2015 in a cohort study of occupational noise exposure workers in Henan Province. According to the type of work, the age difference was not more than 5 years and the length of exposure to noise was not more than 2 years. The polymorphism of 8 single nucleotides in CAT gene was detected by medium SNPscanTM, and the relationship between 8 single nucleotides polymorphism of CAT gene and NIHL susceptibility was analyzed by multivariate conditional logistic regression. Under the dominant model of rs208679 locus of CAT gene [(GA GG)/AA], the risk of NIHL in individuals carrying GA or GG genotype was 1. 431 times higher than that in individuals carrying AA genotype(95%CI 1. 020-2. 009), and P=0. 038. G, a mutant at rs208679 site of CAT gene, may be one of the risk factors for NIHL susceptibility.

Application of Big Data to Support Evidence-Based Public Health Policy Decision-Making for Hearing.

Ideally, public health policies are formulated from scientific data; however, policy-specific data are often unavailable. Big data can generate ecologically-valid, high-quality scientific evidence, and therefore has the potential to change how public health policies are formulated. Here, we discuss the use of big data for developing evidence-based hearing health policies, using data collected and analyzed with a research prototype of a data repository known as EVOTION (EVidence-based management of hearing impairments: public health pOlicy-making based on fusing big data analytics and simulaTION), to illustrate our points. Data in the repository consist of audiometric clinical data, prospective real-world data collected from hearing aids and an app, and responses to questionnaires collected for research purposes. To date, we have used the platform and a synthetic dataset to model the estimated risk of noise-induced hearing loss and have shown novel evidence of ways in which external factors influence hearing aid usage patterns. We contend that this research prototype data repository illustrates the value of using big data for policy-making by providing high-quality evidence that could be used to formulate and evaluate the impact of hearing health care policies.

Combined effect of noise and hand-transmitted vibration on noise-induced hearing loss in the automobile manufacturing industry

Objective: To investigate the combined effect of noise and hand-transmitted vibration on noise-induced hearing loss (NIHL) in the automobile manufacturing industry. Methods: From September 2018 to January 2019, cluster sampling was used to select 998 workers in an automobile factory as study subjects, among whom 352 workers exposed to noise alone were enrolled as noise group, 342 workers exposed to noise and hand-transmitted vibration were enrolled as combined effect group, and 304 workers without exposure to occupational hazardous factors were enrolled as control group. A questionnaire survey and pure tone audiometry were performed for all study subjects. An analysis of variance was used for comparison of continuous data between groups, and the chi-square test was used for comparison of categorical data between groups; a ordinal polytomous logistic regression analysis was used to investigate the influencing factors for NIHL (with 0.05 as the inclusion criteria and 0.10 as the exclusion criteria for independent variables) . Results: There was a significant difference in L(Aeq, 8 h) between groups (P<0.05) ; the noise group and the combined effect group had a significantly higher L(Aeq, 8 h) than the control group (P<0.05) , while there was no significant difference in L(Aeq, 8 h) between the noise group and the combined effect group (P>0.05) . The control group had a significantly lower detection rate of hearing loss than the noise group and the combined effect group (P<0.0125) , and the combined effect group had a significantly higher detection rate of hearing loss than the noise group (P<0.0125) . The ordinal polytomous logistic regression analysis showed that after adjustment for confounding factors such as age, working years, sex, smoking, and drinking, both noise exposure and exposure to both noise and hand-transmitted vibration had an influence on workers' hearing (P<0.05) , and the workers exposed to both noise and hand-transmitted vibration had a higher risk of hearing loss than those exposed to noise alone. Conclusion: There may be a combined effect of noise and hand-transmitted vibration in the automobile manufacturing industry, which can increase the risk of NIHL in workers.

Regulations to reduce risk of hearing damage in concert venues.

In 2015, the World Health Organization (WHO) convened a group of researchers and industry experts to tackle the risk of noise-induced hearing loss from loud music exposure because of personal listening devices and entertainment venues...

Associations of Genetic Variation in Glyceraldehyde 3-Phosphate Dehydrogenase Gene with Noise-Induced Hearing Loss in a Chinese Population: A Case-Control Study.

Objective: The purpose of this paper was to clarify the association between genetic variation in the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene and the risk of noise-induced hearing loss (NIHL). Methods: A case-control study (633 cases and 625 controls) was conducted in this study. Logistic regression was used to analyze the relationships between environmental and individual factors and NIHL. Gene expression levels were compared among each GAPDH rs6489721 genotype and between the case and control groups based on real-time fluorescence quantitative Polymerase Chain Reaction (PCR). Results: The T allele of GADPH rs6489721 was significantly associated with NIHL (odds ratio (OR) = 1.262, 95% confidence interval (CI) (1.066, 1.493), p = 0.006) and showed strong associations in the codominant and dominant models (TT vs. CC: OR = 1.586, 95% CI (1.131, 2.225), p = 0.008; TT vs. TC/CC: OR = 1.391, 95% CI (1.073, 1.804), p = 0.013). The expression level of the TT genotype was significantly higher than that of the CC genotype (p = 0.012), and the expression of the case group was also higher than that of the control group (p = 0.013). Conclusions: The homozygous risk allele (TT) of rs6489721 was associated with an enhanced GAPDH expression, resulting in the development of NIHL in a Chinese population.

Variations in the potassium voltage-gated channel subfamily E regulatory subunit 1 gene associated with noise-induced hearing loss in the Chinese population.

Noise-induced hearing loss (NIHL) is one of the most common occupational health risks in industrialized countries. It has been recognized to result from interactions between genetic and environmental factors. This study investigated the influence of genetic mutations in the potassium voltage-gated channel subfamily E regulatory subunit 1 (KCNE1) gene on susceptibility to NIHL. A total of 2689 industrial workers in eastern China were recruited to participate. Three single-nucleotide polymorphisms (SNPs) of KCNE1 were genotyped in noise-exposed workers who were classified into 589 cases and 639 control individuals. Then, main effects of the genotypes and their interactions with environmental factors were evaluated. Results showed that the rs3453 C allele located in KCNE1 3'-UTR region and the rs1805127 G allele in the encoding region were associated with increased risk of NIHL in the Chinese population. There is an association between TAA, TAG, and other (CAA/CGA) haplotypes (rs3453-rs11702354-rs1805127) and increased risk of NIHL with OR = 1.33, 1.43, and 2.93 (P = 0.022, 0.017, and 0.001 respectively) compared with CGG group. Results also showed a significant interaction between rs3453, rs1805127, and high-temperature exposure (P = 0.0002, adjusted OR = 1.85). The cellular evidence indicated that polymorphisms rs3453 and rs1805127 may play key roles in hearing loss through affecting KCNE1 expressions by the way of microRNA and protein respectively. The further animal study is still needed to confirm these mechanisms. KCNE1 rs3453 and rs1805127 may have a potential as biomarkers for screening the susceptibility to 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.

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.

Single-Nucleotide Polymorphisms in XPO5 are Associated with Noise-Induced Hearing Loss in a Chinese Population.

ObjectivesThe purpose of this study was to investigate the correlation between single-nucleotide polymorphism (SNP) in 3′UTR of XPO5 gene and the occurrence of noise-induced hearing loss (NIHL), and to further explore the regulatory mechanism of miRNAs in NIHL on XPO5 gene and the occurrence of noise-induced hearing loss (NIHL), and to further explore the regulatory mechanism of miRNAs in NIHL on MethodsWe conducted a case-control study involving 1040 cases and 1060 controls. The effects of SNPs on XPO5 gene and the occurrence of noise-induced hearing loss (NIHL), and to further explore the regulatory mechanism of miRNAs in NIHL on ResultsWe genotyped four SNPs (rs2257082, rs11077, rs7755135, and rs1106841) in the XPO5 gene and the occurrence of noise-induced hearing loss (NIHL), and to further explore the regulatory mechanism of miRNAs in NIHL on XPO5 gene and the occurrence of noise-induced hearing loss (NIHL), and to further explore the regulatory mechanism of miRNAs in NIHL on XPO5 gene and the occurrence of noise-induced hearing loss (NIHL), and to further explore the regulatory mechanism of miRNAs in NIHL on XPO5. Conclusion. The genetic polymorphism, rs11077, within XPO5 is associated with the risk of noise-induced hearing loss in a Chinese population.XPO5 gene and the occurrence of noise-induced hearing loss (NIHL), and to further explore the regulatory mechanism of miRNAs in NIHL on

No Shortage of Decibels in Music City: Evaluation of Noise Exposure in Urban Music Venues

To measure and report noise exposure at urban music venues and assess the risk of noise-induced hearing loss by comparing these measures to the National Institute of Occupations Safety and Health (NIOSH) guidelines. Observational study. A commercially available smartphone and external calibrated microphone were used to measure sound levels at urban music venues. The maximum sound level, equivalent continuous sound level, and statistical noise levels (L10, L50, L75, L90) were recorded. The average equivalent continuous sound level was 112.0 (±4.9) dBA, and the average maximum sound level was 127.0 (±3.2) dBA. The L90 average (sound levels at or above this loudness for 90% of measured exposure time) was 101.1 (±5.5) dBA, and the L10 average was 115.2 (±5.0) dBA. Based off of NIOSH guidelines, noise exposure duration at the L10 average should not exceed 28 seconds, and those at the L90 average should not exceed 12 minutes. Smartphone applications using external calibrated microphones can provide useful sound measurements. Data show that randomly sampled music venues may have noise levels that place patrons without hearing protection at risk for noise-induced hearing loss with prolonged exposure. NA Laryngoscope, 131:25-27, 2021.

Association between Smoking and Noise-Induced Hearing Loss: A Meta-Analysis of Observational Studies.

The purpose of this study was to synthesize the results of previously published observational studies through meta-analysis to clarify the association between smoking and noise-induced hearing loss (NIHL). We searched several databases as of October 2019. Based on the results of heterogeneity analysis (Q statistic and I2 statistic), a fixed effect model (for no heterogeneity; Q test P > 0.1 and I2 ≤ 50%) or a random effects model (for heterogeneity) was used to calculate the pooled odds ratios (ORs). We explored the potential dose-response relationship between smoking and NIHL as well. In total, 27 studies involving 30,465 participants were included. Compared with non-smokers, the pooled OR of current smokers was 2.05 (95% Confidence interval (CI): 1.71–2.46), and of former smokers was 1.11 (95% CI: 1.05–1.18). We found a curve linear association between an increasing number of pack-years (packages/day × smoking years) and risk of NIHL. The dose-response meta-analysis suggested that when the number of pack-years was less than fifteen, the risk of NIHL was increasing, and the highest combined OR was 5.25 (95% CI: 2.30–11.96) for pack-years of fifteen. After fifteen pack-years, the pooled OR had a slow decline. Our study indicated that smoking is a risk factor for NIHL. Current smokers have a higher risk than former smokers, and there is a positive dose-response relationship between smoking and NIHL.

Hearing Assessment of Dental Personnel: A Cross-sectional Exploratory Study.

ABSTRACTAim:Dental professionals are prone to have hearing impairment due to prolonged exposure of noise in dental college. The aim of the study was to assess the hearing ability of dental personnel working in Yenepoya Deemed to be University, Mangaluru, Karnataka, India.Materials and Methods:A cross-sectional exploratory study was conducted on 60 subjects (30 male and 30 female). Audiometric analysis was carried out using pure-tone audiometry (PTA) and otoacoustic emission test (OAE).Statistical Analysis:Data were calculated and analyzed using two-way analysis of variance and Tukey’s honestly significant difference test.Results:No statistically significant difference was observed between hearing loss and its association with age, gender, working experience, mean daily working time, and specialization. PTA results showed a statistically significant hearing loss in the left ear, showing a dip at frequency of 4000 Hz among working experience group of 11–15 years and at 6000 Hz for 21–25 years. Also, a statistically significant hearing loss was observed in the left ear at 6000 and 8000 Hz for the age-group of 51–55 years. OAE results were consistent with PTA findings.Conclusion:Dentists and dental personnel are at a higher risk of noise-induced hearing loss. As the working experience increases, the threshold shift is seen to shift from 4000 to 6000 Hz, which is indicative of sensorineural hearing loss due to noise-induced dental environment.

Prevalence, Awareness, and Factors Associated with Noise-induced Hearing Loss in Occupational Motorcyclists in Southwestern Nigeria.

Background:There is generally a lack of awareness among professional motorcycle riders on the risk of noise-induced hearing loss; due to a variety of factors, they are exposed to by the nature of their job. This study, therefore, aimed to determine the prevalence, awareness, and factors associated with noise-induced hearing loss among motorcycle riders in Ido-Ekiti, Ekiti State, Nigeria.Methodology:A cross-sectional descriptive study was conducted between February and March 2019 among 420 motorcycle riders in Ido-Ekiti, Ekiti State, Southwestern Nigeria. Data analyses were performed using the SPSS software version 20. P ≤ 0.05 was considered as statistically significant. Three hundred and sixty of the total of 420 consented for pure-tone audiometry which was done to assess their hearing thresholds.Results:Majority of the respondents had at least a secondary level of education. About 14.5% of the total study population had hearing loss, among which 15% also reported an accompanying ear discharge. All of the respondents did not have any history of hearing loss before they started the occupation. More than half of the study population was aware of noise-induced hearing loss and was able to link it to their profession. None of the study participants used a hearing aid, but 17.9% reported using ear mufflers and 16.2% used earphones while riding.Conclusion:Majority of our respondents had secondary school education and 14.5% of the total study population reported hearing loss, among which 15% also reported an accompanying ear discharge. Furthermore, more than half of the study population was aware of noise-induced hearing loss and was able to link it to their profession, whereas 50% agreed that their occupation placed them at risk of hearing loss.

Frequency of Noise Induced Hearing Loss Among Traffic Wardens of Lahore

Background: Noise-induced hearing loss (NIHL) is a major cause of disability throughout the world. It is the most common irreversible job-related hazard in the world with a higher burden in the developing regions of the world. Certain occupations are at high risk for NIHL. Traffic wardens could be considered highly vulnerable group as they are exposed to long hours of traffic noise. The objective of this study was to determine the frequency of noise induced hearing loss among traffic wardens of Lahore city.Material and Methods: It was a cross-sectional, descriptive study, carried out from 1st December 2018 to 31st May 2019, in which 329 traffic wardens appointed in 34 beats/sectors of Lahore city were included. Data was collected through a structured questionnaire, followed by Pure Tone Audiometry (PTA) of all the subjects.Results: A total of 329 traffic wardens were selected for this study. Mean age of the traffic wardens was 35.35 ± 1.21 years. NIHL was present in 174 (52.9%) traffic wardens, out of which, 138 (79.3%) had mild, 32 (18.4%) moderate, and 4 (2.3%) had moderately severe degree of hearing loss. Among the 329 traffic wardens, 165 (50.2%) had exposure to noise between 7am to 3pm (morning shift) and 42 (12.8%) had some problem with their hearing. Only 12 (3.6%) had ringing in the ears or tinnitus, 140 (42.6%) wore any hearing protection during duty hours and 42 (12.8%) said they had difficulty in hearing and frequently asked people to repeat themselves.Conclusion: In this study a high frequency of noise induced hearing loss was reported among traffic wardens of Lahore city with most of them having mild to moderate degree of hearing loss.

Research and Discussion on the Relationships between Noise-Induced Hearing Loss and ATP2B2 Gene Polymorphism

Long-term and continuous noise exposure can result in noise-induced hearing loss (NIHL), which is a worldwide problem resulting from the interaction of environmental and genetic factors. The ATP2B2 gene polymorphism can destroy cochlear hair cells and increase the risk of NIHL. A case-control study of 760 Chinese textile workers was conducted to investigate the relationship between ATP2B2 polymorphisms and NIHL susceptibility. Venous blood was collected and questionnaires were conducted by professional physicians. A case group and a control group which were typed by individuals' pure-tone audiometry test results were set. Three polymorphism sites of ATP2B2 were genotyped by using the PCR technique. Analysis results revealed that the C allele of rs3209637 (95%CI = 1.08–2.58, odds ratio (OR) = 1.67, P = 0.027) was a dangerous factor and could add to risks of NIHL in the Chinese employees. The data of stratified analysis revealed that individuals who are exposed to noise > 95 dB with the rs3209637 C genotype have a higher susceptibility to NIHL (OR = 1.34, 95%CI = 1.07–1.68). Multifactor dimensionality reduction analysis revealed that the interaction between rs14154 and rs3209637 is linked to increased NIHL risk, and for the interaction among rs14154, smoking and drinking had the same function (OR = 1.54 and 1.77, 95%CI = 1.15–2.07, 1.33–2.37, and P = 0.0037 and P < 0.0001, respectively). Our results suggest that genetic polymorphism rs3209637 C within ATP2B2 is a risk factor for NIHL among Chinese employees and rs3209637 C could be a potential biomarker for NIHL patients.

Analysis of Polymorphisms Associated with Base Excision Repair in Patients Susceptible and Resistant to Noise-Induced Hearing Loss.

Objective Noise-induced hearing loss (NIHL) is one of the most common occupational health risks in both developed and industrialized countries. It occurs as a result of interactions between genetic and environmental factors. Nevertheless, inherited genetic factors contributing to NIHL are not well understood. Therefore, we aim to investigate whether genetic mutations in three important base excision repair genes (OGG1, APEX1, and XRCC1) may influence susceptibility to NIHL. Methods Three SNPs in OGG1, APEX1, and XRCC1 were genotyped from 1170 noise-exposed workers and were classified into 117 most susceptible and 117 most resistant individuals. Results Results showed that the rs1799782 TT genotype located in the XRCC1 coding region and rs1130409 GG/GT in the APEX1 coding region were associated with increased risk for NIHL in a Chinese population. Compared to the rs1799782 C allele frequency, the T allele frequency was increased in the sensitive group (adjusted OR = 1.51, 95%CI = 1.01 to 2.26, P = 0.043). The rs1130409 G allele frequency was also increased in the sensitive group compared to the resistant group (adjusted OR = 1.59, 95%CI = 1.10 to 2.31, P = 0.015). Moreover, rs1130409 and drinking had a statistically significant interaction (P = 0.0002), while rs1799782, rs1130409, and smoking also had a statistically significant interaction (P < 0.0001). Conclusions XRCC1 rs1799782 and APEX1 rs1130409 may have potential as biomarkers for the screening of susceptibility to NIHL in workers exposed severe noise.