Noise-induced hearing loss in randomly selected New York dairy farmers

To understand better the effects of noise levels associated with dairy farming, we randomly selected 49 full-time dairy farmers from an established cohort. Medical and occupational histories were taken and standard audiometric testing was done. Forty-six males (94%) and three females (6%) with a mean age of 43.5 (+/- 13) years and an average of 29.4 (+/- 14) years in farming were tested. Pure Tone Average thresholds (PTA4) at 0.5, 1.0, 2.0, and 3.0 kHz plus High Frequency Average thresholds (HFA3) at 3.0, 4.0, and 6.0 kHz were calculated. Subjects with a loss of greater than or equal to 20 db in either ear were considered abnormal. Eighteen subjects (37%) had abnormal PTA4S and 32 (65%) abnormal HFA3S. The left ear was more severely affected in both groups (p less than or equal to .05, t-test). Significant associations were found between hearing loss and years worked (odds ratio 4.1, r = .53) and age (odds ratio 4.1, r = .59). No association could be found between hearing loss and measles; mumps; previous ear infections; or use of power tools, guns, motorcycles, snowmobiles, or stereo headphones. Our data suggest that among farmers, substantial hearing loss occurs especially in the high-frequency ranges. Presbycusis is an important confounding variable.     

Noise-induced hearing loss,nationality, and blood pressure

Noise exposure has been associated with increased catecholamine production and blood pressure elevation in laboratory studies and in human volunteers. Epidemiologic studies have given conflicting results. In order to determine whether noise-induced hearing loss predicts a rise in blood pressure, we reviewed occupational medicine records in an occupational health center serving three companies where noise exposure is commonly found. Height, weight, blood pressure, and screening audiometry are obtained as par of routine occupational health screening, and the results of the screening visit are abstracted from written clinical records. The results of pure tone screening audiometry are reported in nonstandardized fashion (Normal, WNL, NAD, for example, for normal). We reviewed records from 1990 and 1991 inclusive. One investigator, blind to blood pressure status, assigned each record to “no hearing loss,” “not codable,” or “hearing loss assumed to be due to noise” on the basis of the written audiometry report. Hearing loss due to causes other than noise was considered not codable. No attempt was made to quantify severity of hearing loss. Two hundred and sixteen charts were excluded as “not codable,” 1,535 were classified as having no hearing loss, and 610 had some degree of hearing loss, most probably due to noise exposure. To adjust for confounding covariates, multiple regression analysis was used and indicated that hearing status improves the regression model for predicting diastolic blood pressure (p = 0.04), following age, nationality, body mass index (BMI), and month of testing, although the effect is small. Stratification by age and BMI revealed increased diastolic pressure in the group with hearing loss under age 45, regardless of obesity. Only age and BMI significantly improved the regression model for systolic blood pressure for the group as a whole. However, when large national groupings were evaluated independently, noise-induced hearing loss was associated with higher systolic and diastolic readings among Asians (n = 539) and Sub-Saharan Africans (n = 75), with correlation coefficients ranging from 0.18 to 0.32. Noise-induced hearing loss failed to improve the blood pressure regression model for Europeans/North Americans (n = 150), Arabs (n = 1020), or North Africans (n = 352). In this study, hearing loss attributed to industrial noise exposure appears to be associated with elevated resting blood pressure only within certain ethnic groups.     

Occupational hearing loss in New York dairy farmers.

A study of 49 randomly selected, full-time dairy farmers was performed to assess the prevalence and nature of hearing loss in this population. An age- and sex-matched group of rural, non-farmers was also studied. Medical, occupational, and recreational histories were taken and standard audiometric testing was administered. Sixty-five percent of farmers had hearing loss in the higher frequencies and 37% had losses in the mid-frequency range as compared to 37% and 12% of non-farmers respectively (p less than .01). Farmers' left ears were more severely affected. The age of the subjects and the number of years spent farming were highly correlated with hearing loss. Correlation and regression analyses supported the hypothesis that the difference in the prevalence of hearing loss between the dairy farmers and the non-farmers was due to occupational noise exposure on the farm.     

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.     

Noise exposures of rail workers at a North American chemical facility

BACKGROUND: Both continuous and impact noise exposures of rail yards and railways have been historically understudied. We summarize noise exposures to rail workers at a large chemical facility in North America. METHODS: Rail workers were surveyed over the course of three 12-hr shifts. Personal noise dosimeters were used to derive a 12-hr time-weighted average (L(AVG)), an 8-hr time-weighted average (L(TWA)), and a percent dose. Peak and maximum sound levels were also recorded during each sampling period. Six workers were sampled on three separate days for a total of 18 full-shift noise samples. RESULTS: Full-shift noise exposures were all below the Occupational Safety and Health Administration's (OSHA) permissible exposure limit (PEL) and action level for a 12-hr workday. Peak impact sound levels exceeded 140 dB in 17 of 18 samples (94%) with a mean peak sound level of 143.9 dB. Maximum continuous sound levels were greater than 115 dBA in 4 of 18 samples (22%) with a mean maximum sound level of 113.1 dBA. The source of peak impact sound levels was a daily exposure to a concussion caused by a sudden break in a freight airline. CONCLUSIONS: Rail workers at this facility are at risk of noise induced hearing loss from high impact noise exposures. Peak impact and maximum continuous sound levels can be attenuated through the use of hearing protection or by increasing distances from railroad noise sources.     

Risks of developing noise-induced hearing loss in employees of urban music clubs

Noise-induced hearing loss has previously been reported among rock musicians. This study sought to determine whether a hazard of noise-induced hearing loss exists for music club employees other than musicians themselves. Sound levels at eight live-music clubs were measured and symptoms of noise exposure in 31 music club employees were assessed by questionnaire. The average sound level at the various clubs during performances ranged from 94.9 to 106.7 dBA. The overall sound level average, including both performance and ambient levels, ranged from 91.9 to 99.8 dBA. Symptoms of noise exposure, such as tinnitus and subjective hearing loss, correlated with sound intensity. Only 16% reported regular use of hearing protection. We conclude that employees of music clubs are at substantial risk of developing Noise-Induced Hearing Loss, due to chronic noise exposure which consistently exceeded safe levels. Hearing protection is used much too infrequently. The development of hearing conservation programs for this large group of workers is essential. Am. J. Ind. Med. 31:75–79 © 1997 Wiley-Liss, Inc.     

Five-year follow-up study of hearing loss at several locations within a large automobile company

This longitudinal epidemiologic study was designed to investigate hearing loss over a 5-year period among noise-exposed employees of a large automobile company and to assess effectiveness of hearing conservation programs at locations representing the spectrum of operations (assembly, light manufacturing, heavy manufacturing and machining, metal fabrication, and founding). Based on computerized audiometric test data, the study summarizes methodology developed for measuring occupational hearing loss and its application in evaluating programs at these locations, which had maximal 8-hr time-weighted average (TWA) noise exposures ranging from 104 to 110 dB(A). Methods presented here provide for consideration of age and hearing level of study subjects at baseline audiogram and clearly demonstrate the extent of hearing loss during the study period. Among five study locations, the average hearing loss at 2,000–4,000 Hz in the worst-loss ear ranged from 3.4 to 6.2 dB over the follow-up period; after adjustment for presbycusis, the loss was less than 2 dB at all but one location, which showed a loss of nearly 4 dB. In comparison to a control group of nonnoise-exposed employees, hearing conservation programs at four of the five locations were judged to be effective. One location, a metal fabrication plant with a large percentage of employees having an 8-hr TWA noise exposure over 90 dB(A), was particularly noted for the effectiveness of its program. © 1993 Wiley-Liss, Inc.     

Noise-induced hearing loss and hearing conservation in mining

BACKGROUND: Noise exposure is prevalent in mining, and as the prevalence of noise-induced hearing loss has not changed much in the past two decades, hearing conservation is an important issue. OBJECTIVES: To review the literature and highlight important developments in the field. METHODS: A review of the literature using OVID as the primary search engine, using the search terms as: noise, occupational; hearing loss, noise induced; ear protective devices; and mining. RESULTS: A total of 66 articles were found, but only 11 were in the English language and few were published in the past 10 years. This is disappointing, because neither noise exposure nor the consequent risk of noise-induced hearing loss seems to have changed much in the past 20 years. Noise is, however, a generic hazard, and this article reviews current best practice in prevention.     

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.     

Predicting and classifyng hearing loss in sailors working on speed vessels using neural networks: a field study

Background: Noise-induced hearing loss (NIHL) is one of the main risk factors affecting people''s health and wellbe-ing in the workplace. Analysing NIHL and consequently controlling the causing factors can significantly affect the improvement of working environments. Methods: One hundred and twelve male sailors participated in this study. They were classified into three groups depending on occupational noise exposure: (A) none, i.e., sound pressure level (SPL) lower than 70dBA, (B) exposed to SPL in the range of70-85dBA, and (C) exposed to SPL exceeding 80dBA. In a first phase, hearing loss shaping risk factors were identified and analysed, including hearing loss in different frequencies, age, work experience, sound pressure level (SPL), marital status, and systolic and diastolic blood pressure. Then, neural networks were trained to predict the hearing loss changes of personnel and used to determine the weight ofhearing loss factors. Finally, the accuracy of predicting models was calculated relying on Bayesian statistics. Results and conclusion: In the present study using neural networks, five models were developed. Their accuracy ranged from 92% to 100%. The frequencies of4000Hz and 2000Hz showed the strongest association with the hearing loss of the sailors. Also, including systolic and diastolic blood pressure did not have any impact on predicted hearing loss, indicating that SPL was poorly correlated with extra-auditory effects.     

噪声作业工人血糖水平与噪声性听力损失的关系

目的 探究血糖与性别之间的交互作用对噪声性听力损失(noise-included hearing loss, NIHL)的影响。方法 采用病例对照研究,询问调查噪声作业工人一般资料、职业史、既往史等资料以及职业健康监护资料,进行单因素分析,然后采用logistic回归模型分析NIHL的影响因素,再进行乘法交互作用分析。结果 调查的1 628例噪声作业工人NIHL 616人(37.84%),NIHL的危险因素有血糖偏高(OR=1.960,95%CI:1.345～2.855)、男性(OR=4.346,95%CI:2.866～6.590)、高环境噪声强度(OR=1.036,95%CI:1.016～1.056)、单核细胞计数偏高(OR=8.522,95%CI:3.054～23.776)、血小板偏低(OR=0.997,95%CI:0.994～0.999)。血糖偏高人员的NIHL风险是血糖正常的1.960倍(P<0.01),男性NIHL的风险是女性的4.346倍(P<0.01),环境噪声强度每增加一个单位,NIHL风险提高1.036倍。血糖偏高与男性对NIHL的加法交互作用有统计学意义...     

CASP3和CASP7基因多态性与噪声性听力损失易感性关系

目的 探讨细胞凋亡通路相关基因CASP3和CASP7多态性与中国汉族人群噪声性听力损失（NIHL）易感性之间的关联。方法 研究对象来自2014年杭州市1 549名噪声接触工人听力损失的横断面调查,采用1：1配对病例对照研究,病例组为电测听双耳高频平均听阈>25 dB（A）的工人,对照组为性别、年龄、接噪工龄、工作岗位与病例匹配且双耳所有频段听阈均≤25 dB（A）的工人,共272对。PCR-LDR法检测2个SNP位点的基因型。采用多因素条件logistic回归模型分析SNP位点与NIHL的关联,并以叉生分析计算基因-环境交互作用。结果 χ²检验分析发现,CASP3基因rs1049216等位基因（C、T）频率组间分布有统计学差异（OR=0.68,95%CI=0.50~0.93）,而基因型频率组间差异无统计学意义（P>0.05）;CASP7基因rs10787498等位基因及基因型频率组间分布均无统计学意义（P>0.05）;多因素条件logistic回归显示,CASP3基因rs1049216中,与野生基因型CC相比,突变基因型（CT+TT）为NIHL的保护因素（调整OR=0.65,95%CI=0.43~0.97）;叉生分析表明rs1049216位点与文化程度、睡眠时间存在交互作用（P≤0.001）,NIHL的危险性降低（OR值变小）。结论 CASP3基因rs1049216位点可能与中国汉族人群NIHL易感性有关,且可能与文化程度、睡眠时间存在交互作用。     

The LD50 and Chronic Toxicity of Reactor Terphenyls

Acute ingestion of reactor coolant terphenyls (HB-40) revealed LD₅₀ values of 17,500 mg/kg rat and 12,500 mg/kg mouse for nonirradiated coolant and 6,000 mg/kg mouse or rat for irradiated coolant. Chronic ingestion of the mixtures by mice produced mitochondrial changes in epithelial cells of proximal tubules, and at high doses these cells became necrotic as interstitial nephritis and scarring developed. The nephritis was irreversible and followed 16 weeks’ ingestion of 1,200 mg/kg nonirradiated HB-40 or 600 mg/kg irradiated coolant. Hepatic changes were observed only at the ultrastructural level where abundant smooth endoplasmic reticulum was seen. It appears that organic terphenyl coolants are potentially toxic when ingested in high doses. This could only occur as a result of chronic exposure at a level greatly in excess of that currently observed in the reactor working environment.     

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。     

Noise induced hearing loss and other hearing complaints among musicians of symphony orchestras

Objectives  An investigation of the hearing status of musicians of professional symphony orchestras. Main questions are: (1) Should musicians be treated as a special group with regard to hearing, noise, and noise related hearing problems (2) Do patterns of hearing damage differ for different instrument types (3) Do OAE have an added value in the diagnosis of noise induced hearing loss (NIHL) in musicians. Methods  241 professional musicians, aged between 23–64 participated. A brief medical history and the subjective judgment of their hearing and hearing problems were assessed. Musicians were subjected to an extensive audiological test battery, which contained testing of audiometric thresholds, loudness perception, diplacusis, tinnitus, speech perception in noise, and otoacoustic emissions. Results  Most musicians could be categorized as normal hearing, but their audiograms show notches at 6 kHz, a frequency that is associated with NIHL. Musicians often complained about tinnitus and hyperacusis, while diplacusis was generally not reported as a problem. Tinnitus was most often localized utmost left and this could not be related to the instrument. It was usually perceived in high frequency areas, associated with NIHL. In general, musicians scored very well on the speech-in-noise test. The results of the loudness perception test were within normal limits. Otoacoustic emissions were more intense with better pure-tone thresholds, but due to large individual differences it can still not be used as an objective test for early detection of NIHL. Conclusions  Musicians show more noise induced hearing loss than could be expected on the basis of age and gender. Other indicators, such as complaints and prevalence of tinnitus, complaints about hyperacusis and prevalence of diplacusis suggest that musicians’ ears are at risk. Continuing education about the risks of intensive sound exposure to musicians, with the emphasis on the possible development of tinnitus and hyperacusis and the need for good hearing protection is warranted.     

Surveillance for work-related hearing loss in the UK: OSSA and OPRA 1997-2000

Surveillance data on occupational audiological disorders have been collected by the Occupational Surveillance Scheme for Audiological Physicians (OSSA) since October 1997 and by the Occupational Physicians Reporting Activity (OPRA) from January 1996. During the 3 years ending in September 2000, a total of 1620 new cases were received from consultant audiological physicians; 988 new cases were estimated from reports by occupational physicians in the period from October 1997 to September 2000. The annual incidence of occupational noise-induced hearing loss (NIHL) was 1.94 and 1.23 per 100 000 workers for the OSSA and OPRA schemes, respectively. The median age at diagnosis with NIHL was 59 years in OSSA reports and 50 years in OPRA; nearly all cases were seen in men (95.6 and 92.5% male cases for OSSA and OPRA, respectively). High incidence rates based on OSSA reports were seen in foundry labourers (64.0 per 100 000 employed), coal gas and coke oven furnace workers (54.6), workers in transport and communication (43.1), metal workers (31.3), and members of the armed forces (28.3). Data from occupational physicians point to high rates in sawyers and woodworking machinists, metal furnace workers, coach and carriage builders, maintenance fitters, and engineering labourers. Among workers aged < or =45 years, those in manufacturing and the armed forces were prominent. The long latency of occupational hearing loss makes surveillance difficult, but consistent patterns in occupational risk suggest targets for preventive efforts.     

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.     

Occupational noise-induced hearing loss

Occupational noise-induced hearing loss is, at least in theory,preventable. One way to assess the problem and whether preventativemeasures are effective is to assess employees' hearing. In orderto minimize cost and time off work this can be carried out effectivelyin the workplace as long as certain conditions are met.     

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.