Noise exposure and hearing conservation practices in an industry with high incidence of workers' compensation claims for hearing loss

BACKGROUND: Washington State has experienced a striking increase in workers' compensation claims for hearing loss. METHODS: This cross-sectional study examined noise exposures and hearing conservation practices in one industry with a high rate of hearing loss claims. We evaluated 10 representative foundries with personal noise dosimetry, management interviews, employee interviews, and existing audiometry. RESULTS: Noise levels routinely exceeded 85 dBA. All companies were out of compliance with hearing conservation regulations. Most employees with important findings on audiograms were not aware of their findings. There was a significant positive correlation between management-interview scores and worksite-average employee-interview scores (r = 0.70, P = 0.02). CONCLUSIONS: Companies where more effort is put into hearing conservation program activities can achieve a greater positive impact on employee awareness. However, there were broad deficiencies even in the better programs in this sample, suggesting that workers in this industry probably face a continuing substantial risk of occupational hearing loss.     

Audiometric notch as a sign of noise induced hearing loss

OBJECTIVES—To investigate the relation between different types of exposure to noise and a classic sign of noise induced hearing loss (NIHL), the audiometric notch.METHODS—The study sample had exposure to both continuous and impulse noise and was drawn from a population of electrical transmission workers. Audiograms, taken as part of a hearing conservation programme, were read by three clinicians experienced in the assessment of NIHL. Working independently and using their clinical judgment, they were asked to identify localised increases in the threshold of hearing (audiometric notches) which they would attribute to noise, had a suitable history of exposure been elicited. Prevalent cases of NIHL were identified by the presence of a notch in either ear. Risk factors for NIHL were assessed by a questionnaire which sought information about exposure to air blast circuit breaker noise; firearms; explosions, and continuous noise. The odds of exposure to these factors in those with and without hearing loss were calculated, and odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated by logistic regression.RESULTS—Of the 648 questionnaires sent out 357 were returned, a response rate of 55%. Of these, at least two out of the three assessors identified 175 (49%) people with a notch at any audiometric frequency. There was no association between these cases and the NIHL risk factors identified by the questionnaire, but a further frequency specific analysis showed a small proportion of people (15 (4%)) with notches at 4 kHz who had the expected associations with exposure to noise and a significant OR for firearms of 4.25 (95% CI 1.28 to 14.1). The much larger proportion of people with 6 kHz notches (110 (31%)) did not show these associations.CONCLUSIONS—To diagnose NIHL it is important to elicit a detailed and accurate history of exposure to noise: although the notch at 4 kHz is a well established clinical sign and may be valuable in confirming the diagnosis, the 6 kHz notch is variable and of limited importance.     

Occupational noise exposure and hearing loss: A study of knowledge,attitude and practice among Tanzanian iron and steel workers

Abstract

We assessed Knowledge Attitude and Practice (KAP) regarding occupational noise exposure, Noise-induced hearing loss, audiometry and use of hearing protection devices among iron and steel factory workers exposed to high noise level. A modified, validated, structured questionnaire was used to collect information from 253 male workers randomly selected from the four factories. The sum scores for each domain of KAP were computed. Scores above 75% were defined as good knowledge and positive attitude. For practice, scores of >50% were defined as good. Independent samples t-test and Chi-squared test were used to analyze association between KAP and continuous/categorical variables respectively. Majority of workers displayed poor knowledge and poor practice (94%), but 76% displayed a positive attitude. Most of the workers (86%) had never been provided with hearing protection devices. The mean scores for attitude and practice differed significantly between the four factories (one-way ANOVA, p?<?0.001). Implementation of hearing conservation program with provision of hearing protection devices are suggested.     

Development and pilot test of hearing conservation training for construction workers

BACKGROUND: Hearing conservation efforts in construction frequently rely on use of hearing protection devices (HPDs): however, training on HPDs is often not provided, and usage rates remain low. In this study, a hearing conservation training program was developed and pilot tested. METHODS: A theoretical model was selected as the basis for the program, and program contents and delivery methods were selected to optimize the effectiveness and flexibility of the training. Two evaluation measures were selected to assess training-related changes in self-reported HPD use. The first was a validated method using concurrent work-shift noise dosimetry, and the second was a survey concerning workers beliefs and attitudes towards HPDs and HPD use. RESULTS: The training program was pilot tested on a single construction site. Complete assessment data were available for 23 workers. The percent of time when hearing protection was used during noise levels above 85 dBA nearly doubled post-training, and the change was statistically significant. CONCLUSIONS: Pre- and post-training data from participating workers demonstrated that HPD use can be increased significantly with basic model-based training, even in industries with complex noise exposures such as construction.     

电厂噪声作业工人累积接噪量与听力损害关系

目的　了解电厂噪声作业工人的听力损失发生状况以及与噪声累积暴露量的关系。方法　采用横断面研究方法 ,研究对象为参加噪声作业一年以上的无耳疾患史的 35 6名工人 ,调查年龄、性别、噪声作业的工龄、听力损失情况和作业场所噪声强度。结果　作业工人听力损失的发生率为 31.74%(按人数计 )。听力损失发生率在男、女性别上的分布差别无显著意义。听力损失发生率随累积接触量的增加而增加 ,存在典型的剂量 -反应关系 ,呈明显正相关 (r =0 .9916 ,P <0 .0 5 )。结论　累积接噪量能较全面反映噪声作业工人噪声接触水平 ,是评价噪声暴露与听力损害剂量 -反应关系最好的暴露评价指标。     

Joint effects of smoking, noise exposure and age on hearing loss

BACKGROUND: Smoking has been shown to have adverse effects on hearing, but it's unclear whether smoking interacts with known causes of hearing loss such as noise exposure and ageing. AIMS: To examine the hypothesis that smoking, noise and age jointly affect hearing acuity. METHODS: This cross-sectional study was carried out in 535 male adult workers of a metal processing factory. Pure-tone audiometric tests were utilized to assess hearing loss. Noise exposure assessment was based on a job exposure matrix constructed with industrial hygienist scoring and job titles. Each participant answered questionnaires about socio-demographic, life-style, occupational and health-related data. Analysis of the possible underlying biological model was undertaken assessing departures from additivity using measures of the size of the interaction present. RESULTS: Age and occupational noise exposures were, separately, positively associated with hearing loss. For all the factors combined the estimated effect on hearing loss was higher than the sum of the effects from each isolated variable, especially for smoking and noise among those 20-40 years of age, and for smoking and age among those non-exposed to occupational noise. CONCLUSIONS: The synergistic effect of smoking, noise exposure and age on hearing loss, found in this study, is consistent with the biological interaction. Furthermore, it is possible that distinct ototoxic substances in the chemical composition of mainstream smoke may synergistically affect hearing when in combination with noise exposure, which needs to be examined in future studies.     

Predictors of hearing loss in New York farmers.

BACKGROUND: Data from the telephone interview portion of the New York Farm Family Health and Hazard Surveillance were used to study self-reported hearing loss in New York farmers. METHODS: One thousand six hundred and twenty-two persons completed the hearing loss and noise exposure interview. Hearing loss was defined as at least some trouble hearing in one or both ears. Predictors of hearing loss were determined using logistic regression. RESULTS: Twenty-two percent of participants reported hearing loss. From the logistic regression, significant confounders are age (P = 0.0001), gender (P = 0.0001), being from a livestock farm (P = 0.012), and loss of consciousness due to head trauma (P = 0.04). Significant noise exposures are more hours of lifetime exposure to noisy farm equipment (P = 0.001) and having had a noisy non-farm job (with some hearing protection P = 0.002, without any hearing protection P = 0.0001). CONCLUSIONS: Farm noise exposure is a serious risk to the hearing of this population. Although use of hearing protection should be encouraged, replacing and modifying farm equipment to decrease noise at the source should be the first priority.     

Evaluation of noise-induced hearing loss by reference to the upper limit of hearing

We have defined the upper limit of hearing as the maximum audible frequency measured with fixed intensity and changing frequency. We have previously established the standard upper limit ageing curves from the normal age variation in the upper limit of hearing. In the present study, we sought to clarify the effects of occupational noise on the upper limit of hearing. We measured the upper limit of hearing in 239 healthy male workers (478 ears) exposed to intensive occupational noise. Their age variation in the upper limit of hearing was compared with the standard upper limit ageing curves in males. There were statistically significant deteriorations. Even if the ears that had normal hearing levels (35 dB or less) were selected, deterioration in the upper limit of hearing was noticeable. The upper limit of hearing may serve as clinically useful information on the hearing impairment that precedes noticeable hearing impairment in conventional audiometry for workers exposed to intensive occupational noise.     

噪声所致工人听力损失与高血压的关系

目的研究某钢铁企业工人噪声暴露与高血压的关系。方法选择2014年1~7月底参加职业体检单纯接触噪声工人2061例,按照高频听力损失严重程度分组,即在4000 Hz或者6000 Hz,低听力损失组平均听力损失值(HLVs)15 d B(A)660例,噪声40 h等效声级为(74.69±11.97)d B(A);中听力损失组,15 d B(A)≤HLVs30 d B(A)741例,噪声40 h等效声级为(84.38±11.57)d B(A);高听力损失组,HLVs≥30 d B(A)660例,噪声40 h等效声级为(88.03±14.08)d B(A)。比较三组高血压患病率的差异。结果工人4000 Hz和6000 Hz时,左、右和两耳平均的HLVs值与平均噪声暴露水平显著相关(P0.05)。高血压患病率中听力损失组(29.5%)和高听力损失组(36.1%)明显高于低听力损失组(23.8%)(P0.05)。多因素Logistic回归分析显示,在调整了年龄、心率(HR)、甘油三酯(TG)、噪声40 h等效声级、糖尿病、吸烟、饮酒、体育锻炼等影响因素后,中听力损失组和高听力损失组患高血压的风险较高,其OR值分别为2.14(1.21~3.79)、2.58(1.44~4.62)。结论钢铁企业工人高频噪声引起的听力损失与患高血压的风险有关。     

某矿山开采企业爆破、掘进和采矿作业工人听力损失的情况

目的减少矿山开采企业噪声对机体听觉损伤的危害,使工人听力损失率逐年下降。方法随机调查某矿山开采企业389名作业工人,询问工人的职业接触史、既往史、耳毒药物史、家族史、自觉症状等,并进行耳鼻喉科检查。对389人的气导纯音听阈测试结果进行评级。结果调查对象单耳或双耳听力异常337人,异常检出率为86．63％。单纯高频段听力损失286人,检出率为73．52％。语言频段合并高频段听力损失（包括单纯语言频段听力损失）51人,检出率为13．11％。经统计分析,采矿、爆破、掘进工种的听力异常检出率之间差异无统计学意义（P〉0．05）。语言频段听力损失异常检出率为13．11％。高频段（3、4．6kHz）听力损失依次加重,听力曲线呈斜坡下降型,符合噪声性听力损失特点。爆破组第50百分位数（P50）依次为25,32．5和40dBHL,掘进组为25,32．5和37．5dBHL。结论该企业作业工人听力异常检出率偏高,为此,用人单位不仅要重视职业健康和安全管理工作,坚持开展职业健康监护工作,更要监督指导工人正确使用个人防护用品。特别是对于从事爆破、掘进工作的矿业工人。     

个体噪声防护的职业接触人群听力损失的剂量-反应关系研究

目的准确评价工作场所中使用个体听力防护的噪声接触人群的听力损失。方法对50家企业的3 432名接触噪声工人进行纯音听力测试并对50家接触噪声企业进行职业卫生调查。结果50家噪声接触企业进行职业流行病调查显示噪声强度(92.1±4.9)dB,累积噪声暴露量(CNE)为(103.43±6.66)dB(A).年;在3 432名接触噪声作业人员的听阈检查中,高频损失1 272人(37.06%),语频损失133人(3.88%);高频和语频损失的发生率随累积噪声强度的增大而增大,其发生率与CNE存在剂量-反应关系(P<0.01)。结论高频和语频的发生率随累积噪声强度的增大而增大,呈剂量-反应关系。