Effects of concurrent noise and jet fuel exposure on hearing loss

We sought to examine the effects of occupational exposure to jet fuel on hearing in military workers. METHODS: Noise-exposed subjects, with or without jet fuel exposure, underwent hearing tests. Work histories, recreational exposures, protective equipment, medical histories, alcohol, smoking, and demographics were collected by questionnaire. Jet fuel, solvent, and noise exposure data were collected from records. Fuel exposure estimates were less than 34% of the OSHA Threshold Limit Values. RESULTS: Subjects with 3 years of jet fuel exposure had a 70% increase in adjusted odds of hearing loss (OR = 1.7; 95% CI = 1.14-2.53) and the odds increased to 2.41 (95% CI = 1.04-5.57) for 12 years of noise and fuel exposure. CONCLUSIONS: These findings suggest that jet fuel has a toxic affect on the auditory system.     

听力损伤的累积噪声暴露阈值研究

目的根据不同累积噪声暴露量与工人语频听力损伤发生率间的关系,探讨和评价引起职业性听力损失的临界累积噪声暴露阈值.方法应用Logistic回归模型分析1 435名不同累积噪声暴露强度的听阈数据.结果语频损伤和高频损失发生率随暴露水平而增高;累积噪声暴露量与语频损伤发生率的Logistic回归分析显示,听阈水平随累积噪声暴露量增高而上升并有明显相关性;预测模型显示语频损伤的临界累积噪声暴露阈值为100dB(A).结论听力损伤的临界累积噪声暴露阈值100dB(A)与我国现执行的噪声卫生标准具有一致性,可探讨作为对个体职业噪声暴露危害程度警告的阈值指标.     

高水平苯乙烯接触加重噪声对听力影响的研究

目的 探讨高水平苯乙烯接触和噪声协同作用对职业人群纯音听力结果的影响。
方法 选择某运动器材企业同时接触高水平苯乙烯和噪声的114名生产工人为观察组,单纯接触噪声的97名工人为对照组。分析研究对象不同苯乙烯接触水平下的听力检查结果。
结果 观察组空气中苯乙烯的时间加权平均浓度为（402.81±52.25）mg/m3,合格率为16.67%;对照组的空气中苯乙烯的时间加权平均浓度为未检出。观察组噪声接触水平的8 h等效声级均值为（87.1±1.1）dB（A）,对照组噪声接触水平的8 h等效声级均值为（86.7±1.0）dB（A）,两组接触水平差异无统计学意义（P>0.05）。观察组的听力损失检出率为19.2%,对照组的听力结果异常率为8.2%;观察组和对照组的高频平均听阈分别为（28.3±9.0）dB、（25.0±2.7）dB,观察组的高频听力损失检出率高于对照组,而且随着苯乙烯接触浓度（< 213 mg/m3、213~426 mg/m3、>426 mg/m3）递增,高频听力损失检出率分别为6.5%、25.0%、47.6%。
结论 高浓度的苯乙烯增加听力损伤的风险,可能与噪声具有一定的协同作用,影响职业人群的听力神经系统。应把同时接触噪声和高水平苯乙烯的接触人群列为重点健康监护对象,实施以无毒或低毒物质替代苯乙烯和减少噪声接触时间等多种防治措施,保护工人听力系统的健康。
     

Sensory-neural hearing loss during combined noise and vibration exposure

Summary A detailed analysis of risk factors for the development of sensory-neural hearing loss (SNHL) was carried out on 122 forest workers. These forest workers were selected from a larger group (n = 217) by restricting the age range to 30–55 years. The hearing threshold of the left ear at 4000 Hz was measured and the effect of age, exposure, systolic and diastolic blood pressure (DBP), presence of vibration-induced white finger (VWF), tobacco smoking and use of earmuffs were evaluated in multiple linear regression analysis. Robinson's nonlinear model was used to evaluate the rate of hearing loss. Aging was the major risk factor and it explained 15.4% of the variance of the SNHL. The presence of VWF was the second most important single risk factor and explained a further 5.2% of the SNHL. Elevation of DBP correlated significantly with SNHL and explained an additional 4.1% of the SNHL. These main factors were able to explain about 26% of the spread of SNHL. Additional factors in the analysis, e.g. smoking, systolic blood pressure, did not significantly contribute to the genesis of SNHL. When Robinson's model was applied to the SNHL data, on a group basis, we did not observe any exaggerated risk of hearing loss due to combination of noise and vibration. In combined exposure subjects with VWF as well as subjects with enhanced DBP will run a higher risk for SNHL.     

噪声累积暴露对不同频率纯音气导听阈的影响

本研究以LEX,w=80.3 (78.9,82.1)dB(A)为暴露水平,探讨不同频率纯音气导听阈的改变特征和噪声性听力损失(NIHL)的时间累积效应.结果 显示,噪声累积暴露与高频听力损伤存在剂量-反应关系,对语频听阈的影响有待进一步探索;NIHL呈双侧性和对称性特征,以6000 Hz听阈受损为主.     

Transient shift in hearing threshold in simultaneous exposure to noise and postural activities

Experimental results indicate that work posture--conditioned loads in exposure to broadband and narrow-band noise (L = 85 dB [A]) modify the amount of the noise-induced TTS2.     

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.     

Combined exposure to noise and vibration and its effects on workers' hearing

OBJECTIVE: To assess the exposure of bus drivers to noise and whole-body vibration (WBV) and to examine the possibility of an association between these risk factors for noise-induced hearing loss. METHODS: A cross-sectional study was carried out among 141 bus drivers who underwent an audiometry test. This group was classified and internally stratified in subgroups of "exposed" and "controls" according to cumulative working time as bus drivers. Their exposure to noise and vibration was assessed. The association between noise-induced hearing loss (NIHL) and the set of explanatory variables was analyzed through logistic regression. RESULTS: The average (+/- standard deviation) weekly noise exposure of front-engine bus drivers was 83.6 +/- 1.9 dB(A), while rear-engine bus drivers were exposed to 77.0 +/- 1.1 dB(A). The weighted average of vibration acceleration was 0.85/m(2). In the best adjusted model, the multivariable analysis showed that age (>44; OR=2.54; 95% CI=1.15-5.62), diabetes (OR=5.46; 95% CI=0.95-31.4), and the level of noise emission [>86.8 dB(A); OR=2.76; 95% CI=1.24-6.15] were risk factors for NIHL. In another model studied, WBV exposure was significant in determining NIHL. CONCLUSIONS: Bus drivers were exposed to significant WBV levels. The noise exposure was more pronounced in front engine than in rear-engine vehicles. No association between WBV exposure and NIHL was observed and no interaction was found between WBV and noise exposure. Further studies are required as other model indicated an association between WBV and NIHL.     

饮酒与职业噪声暴露对听力损失的联合作用

目的 探讨饮酒与听力损失的关系以及饮酒和职业性噪声对听力损失的联合作用.方法 利用回顾性队列研究,选择广州市某大型空调生产企业连续性噪声作业人员2.44名男性饮酒者为饮酒组,在相同的噪声暴露环境中选择140名男性不饮酒者为对照组,两组间除饮酒外,其他均均衡可比.按照<作业场所噪声测量规范>(WS/T 69-1996)要求对噪声暴露作业场所进行测点选择和噪声强度测量[dB(A)],并计算累积噪声暴露量(CNE).按GB7583-87要求,对工人进行左、右耳500～6000Hz内6个频率的纯音气导听阈测试,并问卷调查其一般情况、个人生活史、职业史、噪声暴露史、家族性耳聋史以及耳毒性药物使用史等.利用t检验、有序多分类logistic回归分析、卡方检验分析噪声和饮酒对听力的影响以及两者的联合作用.结果 同一噪声暴露环境下,在4 000 Hz频段,饮酒组左、右耳听阈位移分别为(29.9±12.9)dB和(30.0±13.5)dB;6000Hz听闻位移为(26.9±11.8)dB和(27.3±15.3)dB,均高于对照组(P<0.05).饮酒组听力损失的发生率为21.7%,对照组为10.7%,两组比较差异有统计学意义(P<0.01),年饮酒量达32L及以上听力损失发生的相对危险度是不饮酒的2.632倍(P<0.05).累积噪声量达80 dB(A)及以上时,饮酒和职业噪声听力损失的RR值分别为3.353和4.643,饮酒与职业噪声联合作用的RR值(9.662)大于两个变量独立作用之和.结论 大量饮酒可导致听力损失发生率增高,在高强度噪声暴露情况下,饮酒和职业噪声暴露对听力损失存在协同作用.     

电焊烟尘与噪声联合作用对作业工人听力损伤的调查

目的 了解电焊烟尘与噪声联合接触对工人听觉系统的影响.方法 检测纯音听闻及血液指标.结果 联合接触组听力损伤检出率明显高于噪声接触组(P<0.05).结论 电焊烟尘与噪声等有害因素联合接触可加重工人听觉系统的损伤.     

Effect of exposure to a mixture of solvents and noise on hearing and balance in aircraft maintenance workers

Aircraft maintenance workers are exposed to a mixture of solvents in the presence of intermittent noise. For this study these workers exposed to solvent mix and noise, were compared with mill workers exposed to noise alone, printed circuit board operatives exposed to solvents alone and those exposed to none who acted as controls. Tympanometry, acoustic reflex thresholds, transient and distortion product otoacoustic emissions, auditory brainstem potentials, nystagmography and posturography were examined. There was a significant effect on pure tone thresholds for both noise and solvents+noise. The distortion product otoacoustic emissions declined with frequency and exhibited lower DP amplitude with noise compared to solvents and noise group. The transient emissions showed a similar effect. Over 32% of subjects with solvent and noise exposure had abnormalities of the auditory brainstem responses in terms of interwave interval prolongation. The mean acoustic reflex thresholds showed a pattern of differences which differentiate noise from solvent and noise groups. The contralateral pathway appears to be differentially affected by solvent exposure. 32% of subjects in the solvents and noise group had an abnormal posturographic finding. In the solvents and noise group 74% had abnormalities of saccades, 56% of pursuit and 45% of optokinetic nystagmus.     

甲苯与职业性噪声接触对听力损失的联合作用

目的 探讨甲苯与噪声联合接触对听力损失的影响。 方法 选择珠海市两家企业中同时接触甲苯和噪声人员78例为混合接触组,单纯接触噪声人员75例为噪声接触组,不接触职业病危害因素的办公室和后勤人员90例为对照组,进行现场甲苯浓度和噪声强度检测,对三组研究对象进行纯音测听检查,并对结果进行统计学分析。 结果 接触组各作业点甲苯浓度、噪声强度均超过国家职业接触限值。混合接触组与噪声接触组在高频段(3.0 kHz、4.0 kHz、6.0 kHz)听阈值差异有统计学意义(P均<0.05)。混合接触组与对照组比较,各频段听力差异均有统计学意义(P均<0.05)。混合接触组、噪声接触组的语频听力异常检出率(25.6%、22.7%)均高于对照组(2.2%),差异均有统计学意义(P<0.05/3);混合接触组的高频听力异常检出率(51.3%)均大于噪声组(24.0%)和对照组(7.8%),差异有统计学意义(P<0.05/3)。工龄≥ 5年者,混合接触组与噪声接触组听力损害发生率差异有统计学意义(P<0.05)。 结论 甲苯与噪声联合接触对听力损害有协同作用,应充分考虑联合接触因素的职业安全防护。     

IV. Extra-auditory effects in long-term exposure to aircraft and traffic noise

Summary 12 male Ss were exposed for 3 h to aircraft noise (peak value: 89–100 dB(A)) or traffic noise (Leq : 73.2 dB(A)); a mental task had to be carried out for 8 min at the end of each hour. Exposure to traffic noise caused decrease of systolic blood pressure, increase of diastolic blood pressure, decrease of pulse pressure, heart rate and quotient of heart rate and respiratory rate and increase of respiratory rate. Aircraft noise effects tended to go into the same direction, but were only significant for diastolic blood pressure (increase) and pulse pressure (decrease). Binary choice capacity was impaired only in case of exposure to aircraft noise.In the course of the 3 hours exposure to aircraft noise and also traffic noise there was a further increase of diastolic blood pressure. The other parameters were not affected by duration of exposure.These results strongly suggest that long-term exposure to noise is a risk factor for cardiovascular disease in daily living and working conditions.     

II. Extra-auditory effects in short-term exposure to aircraft and traffic noise

Summary A series of human studies was performed in 12 young healthy male subjects to investigate extra-auditory effects of short-term (15 min) exposure to aircraft noise (84–91 dB(A)), to traffic noise (Leq 83.5 dB(A)), to mental load, and to combined load (noise + mental load). Exposure to noise caused increase of diastolic blood pressure and respiratory rate, decrease of pulse pressure and quotient of heart rate/respiratory rate and also decrease of performance in a mental task. Aircarft and traffic noise generally induce similar effects, which go into the same direction as induced by mental performance alone. Combined exposure induces a stronger (but not additive) effect on diastolic blood pressure and respiratory rate than each condition alone. There is suggestive evidence that exposure to noise and performance of an information processing task both induce simultaneous increase of sympathic and parasympathic tone.     

高温与噪声的联合作用对玻璃制瓶工听力的影响

选择4组组间基本均衡的现场进行噪声和高温测试,分析4组研究对象听力水平的差异。对68名不同高温噪声暴露时间的玻璃制瓶工进行听力水平比较。结果发现,对语频听阈和高频听阈,单纯高温组与对照组相比差异无显著性(P>0.05),噪声组、高温噪声组与对照组相比差异有显著性(P<0.01),高温噪声组明显高于噪声组(P<0.01)。语频听阈和高频听阈随高温噪声暴露时间的延长而增高(P<0.01)。提示高温本身对语频听阈和高频听阈没有影响,但高温与噪声的联合作用可加重噪声对听力的损害,且可能具有时间依赖性。     

Predictors of hearing threshold levels and distortion product otoacoustic emissions among noise exposed young adults

Aim: To examine the relations between noise exposure and other risk factors with hearing function as measured by audiometric thresholds and distortion product otoacoustic emissions.

Methods: A total of 456 subjects were studied (393 apprentices in construction trades and 63 graduate students). Hearing and peripheral auditory function were quantified using standard, automated threshold audiometry, tympanometry, and distortion product otoacoustic emissions (DPOAEs). The analysis addressed relations of noise exposure history and other risk factors with hearing threshold levels (HTLs) and DPOAEs at the baseline test for the cohort.

Results: The cohort had a mean age of 27 (7) years. The construction apprentices reported more noise exposure than students in both their occupational and non-occupational exposure histories. A strong effect of age and years of work in construction was observed at 4, 6, and 8 kHz for both HTLs and DPOAEs. Each year of construction work reported prior to baseline was associated with a 0.7 dB increase in HTL or 0.2 dB decrease DPOAE amplitude. Overall, there was a very similar pattern of effects between the HTLs and DPOAEs.

Conclusions: This analysis shows a relatively good correspondence between the associations of noise exposures and other risk factors with DPOAEs and the associations observed with pure-tone audiometric thresholds in a young adult working population. The results provide further evidence that DPOAEs can be used to assess damage to hearing from a variety of exposures including noise. Clarifying advantages of DPOAEs or HTLs in terms of sensitivity to early manifestations of noise insults, or their utility in predicting future loss in hearing will require longitudinal follow up.

     

Combined effects of hand-arm vibration and noise on temporary threshold shifts of hearing in healthy subjects

 Object: To investigate whether hand-arm vibration and noise have a combined effect on temporary threshold shift (TTS) of hearing among healthy subjects. Method and design: Nineteen healthy subjects with an average age of 25.7 (SD 7.7) years were exposed to vibration (30 m/s², 60 Hz), noise [90 dB(A)] and both, respectively. The subject’s right hand was placed on the plate of a vibrator and the right ear exposed to noise via headphones. Subjects were exposed to vibration and/or noise for 3 min and after a 1-min pause the exposure was repeated five times. Hearing thresholds at 1, 4 and 6 kHz were measured during the time periods before, between (during pauses) and after exposure. Results: Exposure to vibration alone caused almost no hearing threshold changes at every frequency tested. But exposure to noise or a combination of vibration and noise caused a significant increase in TTSs at 4 and 6 kHz. Moreover, exposure to a combination of vibration and noise caused significantly higher TTSs than exposure to noise at 4 and 6 kHz. Conclusion: The present results demonstrate the combined effects of hand-arm vibration and noise on hearing: simultaneous exposure to hand-arm vibration and noise can enhance the TTS of hearing more than noise exposure, though hand-arm vibration alone may hardly affect TTS. Received: 14 May 1996/Accepted: 20 September 1996