中低剂量稳态噪声对工人高频听力损伤的影响

本文在１２０名接触中低剂量稳态噪声、未出现语频听力损伤的工人中发现高频听力损伤４２人（经年龄性别较正，患病率３５．０％），累积噪声暴露量由＜７５ｄＢ（Ａ）增加至＞９５ｄＢ（Ａ）时高频听力损伤患病率由６．３％上升至５３．３％。用Ｌｏｇｉｓｔｉｃ回归模型进一步观察到累积噪声暴露量增加１ｄＢ（Ａ）时调整后的ＯｄｄｓＲａｔｉｏ为１．１３６（Ｐ＝０．００１），证实中低剂量稳态噪声暴露与高频听力损伤之间仍存在剂量——反应关系。同时，这一规律与过去在中高剂量噪声暴露的人群中观察到高频听力损伤的剂量——反应关系互相衔接。作者认为长期接触中低剂量稳态噪声仍可以在一定程度上引起高频听力损伤，对这一部分人群的防护也应予以注意。     

接触非稳态噪声与听力损伤的剂量-反应关系研究

目的为评价接触非稳态噪声与听力损伤的剂量-反应关系和探索非稳态噪声接触剂量的描述指标提供科学依据。方法通过问卷调查收集调查对象的基本信息,用个人噪声剂量计记录噪声接触水平,并对调查对象进行纯音听力测试。结果204名机械作业工人接触噪声符合非稳态特征,LAeq.8h为80.6～112.3dB(A);语频听力损伤患病率为17.2%,高频听力损伤患病率为59.3%。接触非稳态噪声与高频、语频听力损伤患病率均呈现剂量-反应关系(趋势卡方检验P<0.01)。Logistic回归分析显示,SLAeq.2s、RLAeq.2s、四分位数间距LAeq.2s与高频损伤,SLAeq.2s指标存在统计学关联(P<0.01),而RLAeq.2s、四分位数间距LAeq.2s与高频听力损伤无关联(P>0.01)。结论接触非稳态噪声较稳态噪声对语频听力损伤更为敏感;累计噪声接触量指标同样适用于非稳态噪声,用于评价噪声接触、预测听力损伤水平;今后研究中可以尝试采用SLAeq.2s作为描述不同性质的非稳态噪声波动性指标。     

中低剂量噪声暴露与工人高频听力损伤的剂量-反应关系

本文在１２０名接触中低剂量噪声，未出现语频听损的工人中发现高频听力损作４２人，累积噪声暴露量由〈７５ｄＢ增加至〉９５ｄＢ时，高频听力损伤患病率由６．３％上升至５３．３％。用Ｌｏｇｉｓｔｉｃ回归模型进一步观察到累积噪声暴露量增加１ｄＢ（Ａ）时，调整后的Ｏｄｄｓ Ｒａｔｉｏ为１．１３６，证实中低剂量噪声暴露与高频听力损伤存在剂量－反应关系，长期中低剂量噪声可在一定程度上引起高频听力损伤。     

中低剂量噪声暴露与工人高频听力损伤的剂量－反应关系

本文在１２０名接触中低剂量噪声、未出现语频听损的工人中发现高频听力损伤４２人（经年龄性别校正，患病率３５．０％），累积噪声暴露量由＜７５ｄＢ（Ａ）增加至＞９５ｄＢ（Ａ）时，高频听力损伤患病率由６．３％上升至５３．３％。用Ｌｏｇｉｓｔｉｃ回归模型进一步观察到累积噪声暴露量增加１ｄＢ（Ａ）时，调整后的ＯｄｄｓＲａｔｉｏ为１．１３６（Ｐ＝０．００１），证实中低剂量噪声暴露与高频听力损伤之间存在剂量－反应关系，长期接触中低剂量噪声可在一定程度上引起高频听力损伤。     

两种测量方法评价稳态噪声暴露与高频听力损伤的剂量-反应关系

目的 比较环境噪声水平、个体噪声暴露和累积噪声暴露量评价稳 态噪声所致听力损伤剂量－反应关系的优劣。方法 用个体计量仪采集8小时工作期间挡车工的噪声暴露数据,并将数据传输至微机存储和分析。选择细砂、布机车间使用不同类型机器的4组工人作为观察对象,每组选择3－5人,分别在早、中、晚班各测量1个班次的个体噪声暴露数据;用网格法和普通声级计测量每组工人工作环境的噪声水平,同时对该纺织厂接触稳态噪声的163名工人进行了问卷和听力检查。结果 经年龄、性别校正后的高频听力损伤患病率为64．4％;语频听力损伤患病率为2．5％,其中高频听力损伤患病率随噪声暴露的剂量增大而升高,呈现典型的剂量－反应关系。经趋势卡方检验和和Logistic回归模型拟合,累积噪声暴露量评价剂量－反应关系的效果优于噪声级,个体噪声暴露的效果优于环境噪声水平。结论 个体噪声暴露和累积噪声暴露量是评价稳态噪声暴露与高频听力损伤剂量－反应关系最好的暴露评价指标。     

轨枕厂噪声作业工人听力水平的调查研究

目的 了解铁路轨迹厂噪声作业对工人听力水平的影响，为采取防护措施提供依据。方法 对现场作业进行噪声测试，对工人进行听力损伤测试。结果 噪声作业工人的高频和语频听力损伤率明显高于对照组，高频和语频听力损伤率均随累积接触噪声剂量的增加而升高，呈明显的剂量-反应关系。听力曲线为“V”型，高频“V”凹陷谷点以6kHz为主，占68.45%。结论 轨枕厂的高强度噪声对作业工人听觉系统有明显的损害。     

深圳龙岗区职业性噪声与听力损失的流行病学研究

目的 对调查深圳市龙岗区噪声企业工人听力损失的评价指标进行探讨。方法 采用横断面流行病学调查方法，对深圳市龙岗区6家企业的稳态噪声作业环境进行调查，对386名接触噪声人员进行职业卫生学调查和听力测定，听力测定参照《职业性听力损伤诊断标准》（GBZ49—2002），并计算累积噪声暴露量（CNE）。结果 386名噪声作业人员高频听力损伤发生率为74．09％，语频听力损伤发生率为50．52％；随CNE增加，听力损伤发生率有增高趋势（P〈0．05）；Logistic回归分析表明，高频、语频听损发生率与CNE呈显著相关，而与工龄的相关性不明显。结论 在特区经济模式下CNE作为听力健康的评价指标比工龄史敏感。     

噪声对汽车制造工人听力的影响

目的了解噪声对汽车制造工人听力的影响,旨在探讨听力保护措施与筛查重点防护人群。方法依据相关规范标准对393名汽车制造企业接触噪声作业工人听力损伤进行调查分析,并与不接触噪声的对照组工人进行对比分析。结果接触平均噪声89．8dB（A）工人听力损伤（耳）检出率为35．1％,显著高于对照组,检出率随工龄增长而增加,并且脉冲噪声接触工人听力损伤（耳）检出率高达57．1％,高于稳态噪声接触组。结论该人群听力损伤检出率较高,噪声危害应采取治理、个体防护、加强监护的综合措施,调试工因工作原因不能佩戴耳塞防护,是噪声监护的重点人群。     

稳态噪声与非稳态噪声所致工人听力损害的对比研究

目的评价两种不同性质的噪声对工人听力损害的差异方法对35家企业的稳态噪声接触1年以上工人共1421人,非稳态噪声(除脉冲噪声之外)接触1年以上冲压工人共957人进行纯音听力测试,并对35家接触噪声企业进行职业卫生学调查。结果在1421名稳态噪声组检出观察对象131例,患病率为9.2%,职业性噪声聋98人,患病率为6.8%;在957名非稳态噪声组检出观察对象74例,患病率为7.7%,职业性噪声聋60人,患病率为6.3%。两组比较差异无统计学意义(P0.05)。两组高频和语频听力损失的患病率随累积噪声暴露量的增大而增大,呈剂量-反应关系。结论在累积噪声暴露量接触水平一致的情况下,稳态噪声与非稳态噪声(除脉冲噪声之外)对引起的听力损失差异无统计学意义。     

北京市朝阳区电子企业噪声作业工人990例健康状况调查

目的探讨电机电器噪声对相关作业人员健康状况的影响。方法选择北京市朝阳区6个电子企业接触噪声作业工人990名和非接触噪声工人（对照组）775名进行健康检查,测定计算每组的语频、高频听力损伤值,进行统计学分析。结果噪声接触组高频听力损伤、神经衰弱、语频听损、心电图异常和高血压的检出率均高于对照组（P〈0.05）。结论长期接触工业噪声对听觉系统、神经系统及心血管系统有一定影响。     

噪声作业对生产工人听力影响的调查与分析

本文对1083 名稳态噪声作业、135名脉冲噪声作业及467 名非噪声作业职工进行了听力检查,结果表明: 稳态噪声、脉冲噪声作业职工听力损伤发生率分别是47.8% 、65.9% , 听损检出率显著高于对照组 (8.1% ), P< 0.01; 脉冲组听损检出率显著高于稳态组(P< 0.01)。听力损伤检出率随噪声暴露水平、累积噪声暴露量及接噪工龄的增长而增高, 均表现为正相关关系 (r= 0.9211～0.9874, P< 0.05), 呈明显的剂量反应关系     

用个体暴露评价脉冲噪声与稳态噪声所致高频听力损失的关系

目的用个体噪声暴露测量数据比较工业脉冲噪声与稳态噪声所致高频听力损失剂量反应关系的异同。方法1998至1999年,以32名接触脉冲噪声的机械制造工人和163名接触稳态噪声的纺织工人为观察对象,用噪声剂量计采集8h工作期间的噪声暴露数据,计算8h等效声级(LAeq.8h),并按等能量原理将LAeq.8h和噪声作业工龄合并为累积噪声暴露量(CNE)。用常规方法测量工人左右耳气导听阈,按GBZ492002对听阈做年龄性别校正,并诊断是否为高频听力损失。结果脉冲噪声组的CNE[(103.2±4.2)dB(A)·年]明显低于稳态噪声组[(110.6±6.0)dB(A)·年],脉冲噪声组高频听力损失患病率(68.8%)与稳态噪声组(65.0%)相似,分层分析和趋势卡方检验证实,两组CNE与高频听力损失患病率间均存在典型的剂量反应关系,差异有统计学意义;脉冲噪声100～104和105～109dB(A)·年两组的高频听力损失患病率(76.9%和90.9%)高出稳态噪声组(30.4%和50.0%)约1倍。logistic回归模型显示,脉冲噪声组CNE与高频听力损失患病率的剂量反应关系曲线与稳态噪声组相比出现曲线左移,斜率增大。结论采用个体噪声暴露数据计算时,在能量相同的情况下,脉冲噪声所致高频听力损失的危害大于稳态噪声。     

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.     

谷胱甘肽硫转移酶M1和T1基因多态性与噪声性听力损失易感性的关系研究

目的探讨谷胱甘肽硫转移酶M1和T1(GSTM1和GSTT1)的基因多态性与噪声性听力损失易感性之间的关系。方法采用横断面流行病学研究方法,对194名噪声暴露作业工人进行调查和听力测试,按听力学评价的结果将其分为听力损失组和听力正常组。用多重PCR方法检测其GSTM1和GSTT1的存在空白基因多态性。结果GSTM1和GSTT1的存在空白基因型分布在93名噪声性听力损失与101名听力正常工人之间差异无显著性(P>0.05)。采用多元Logistic回归分析对两组间年龄、性别、吸烟状况、爆震史和累积噪声暴露量等因素进行校正后,发现GSTT1空白基因型组与GSTT1存在基因型组相比噪声性听力损失的危险度显著性升高(P<0.05),调整OR值为1.952(95%可信区间为1.017～3.746);GSTM1存在与空白基因型之间发生噪声性听力损失的相对危险度差异无显著性(P>0.05)。结论谷胱甘肽硫转移酶T1基因多态性可能在噪声性听力损失的发病过程中起一定作用,携带GSTT1空白基因型的个体对噪声性听力损失的易感性升高。     

Air blast circuit breaker noise and hearing loss: a multifactorial model for risk assessment

The assessment of the risk to hearing from impulse noise exposure may be a problem for the occupational physician because existing legislative and international noise exposure standards deal primarily with continuous noise, and are not valid in excess of the peak exposure limit of 200 pa (140 dB). Noise exposure in excess of this level, for example that due to firearms, is frequently perceived as harmful, but this is not necessarily the case, as impulse noise standards do, in fact, allow exposure with a maximum in the order of 6.3 kPa (170 dB). To illustrate this, a cross-sectional group of electrical transmission workers have been studied who were exposed to significant levels of impulse noise from air blast circuit breakers and firearms. Important hearing loss factors have been identified by means of a specially designed questionnaire. Using the Health & Safety Executive definition, the risk of hearing loss was determined by calculating prevalence odds ratios (ORs) for exposure to these factors. The OR for those with fewer than eight unprotected air blast circuit breaker exposures was 2.27 (95% confidence interval (CI), 1.01-5.08), whilst for those with more than eight exposures the OR was 2.10 (95% CI, 0.97-4.54). For firearm exposure, ORs of 1.61 (95% CI, 0.95-2.74) were noted in the medium exposure group and 2.05 (95% CI, 1.08-3.86) in the high exposure group. When all the factors were included in the model, the most significant factor was age. The study gives support to the impulse noise exposure criteria, confirming the borderline risk from air blast circuit breaker noise exposure and the relative safety of moderate gunfire exposure.     

Noise exposure assessment among groundskeepers in a university setting: A pilot study

Approximately 870,000 U.S. workers are employed as landscaping and groundskeeping workers who perform various tasks and use a variety of tools that expose them to high noise levels, increasing their risk to noise-induced hearing loss (NIHL). Several studies on noise exposure and NIHL in other job sectors have been published, but those on groundskeepers are very limited. This study aims to characterize the noise exposure of groundskeepers. Participants were monitored over their entire work shift for personal noise exposure by wearing noise dosimeters at shoulder level, 4 in from the ear. Using two different dosimeter settings (OSHA and NIOSH), the time-weighted averages (TWAs) and 1-min averages of noise exposure levels in decibels (dBA) were obtained. The participants were also asked to fill out an activity card daily to document their tasks, tools used, location and noise perception. Sound pressure levels (SPLs) produced by various groundskeeping equipment and tools were measured at full throttle near the ear of the operator using a sound level meter. These measurements were used to assess worker noise exposure profiles, particularly the contributing source of noise. The overall mean OSHA and NIOSH TWA noise exposures were 82.2±9.2 (range of 50.9–100 dBA) and 87.8±6.6 dBA (range of 67.2–102.9 dBA), respectively. Approximately 46% of the OSHA TWAs exceeded the OSHA action limit of 85 dBA. About 76% of the NIOSH TWAs exceeded 85 dBA, and 42% exceeded 90 dBA. The SPLs of equipment and tools measured ranged from 75– 106 dBA, most of which were at above 85 dBA and within the 90–100 dBA range. Hand-held power tools and ride-on equipment without enclosed cab may have contributed significantly to worker noise exposure. This study demonstrates that groundskeepers may be routinely exposed to noise levels above the OSHA and NIOSH exposure limits, and that the implementation of effective hearing conservation programs is necessary to reduce their risk to NIHL.     

Follow-up of hearing thresholds among forge hammering workers

Hearing threshold was reexamined in a group of forge hammering workers investigated 8 years ago with consideration of the age effect and of auditory symptoms. Workers were exposed to impact noise that ranged from 112 to 139 dB(A)—at an irregular rate of 20 to 50 drop/minute—and a continuous background noise that ranged from 90 to 94 dB(A). Similar to what was observed 8 years ago, the present permanent threshold shift (PTS) showed a maximum notch at the frequency of 6 kHz and considerable elevations at the frequencies of 0.25–1 kHz. The age-corrected PTS and the postexposure hearing threshold were significantly higher than the corresponding previous values at the frequencies 0.25, 0.5, 1, and 8 kHz only. The rise was more evident at the low than at the high frequencies. Temporary threshold shift (TTS) values were significantly less than those 8 years ago. Contrary to the previous TTS, the present TTS were higher at low than at high frequencies. Although progression of PTS at the frequencies 0.25 and 0.5 kHz was continuous throughout the observed durations of exposure, progression at higher frequencies occurred essentially in the first 10 to 15 years of exposure. Thereafter, it followed a much slower rate. Tinnitus was significantly associated with difficulty in hearing the human voice and with elevation of PTS at all the tested frequencies, while acoustic after-image was significantly associated with increment of PTS at the frequencies 0.25–2 kHz. No relation between PTS and smoking was found. PTS at low frequencies may provide an indication of progression of hearing damage when the sensitivity at 6 and 4 kHz diminishes after prolonged years of exposure. Tinnitus and acoustic after-image are related to the auditory effect of forge hammering noise.     

外周血淋巴细胞热休克蛋白60和70表达水平与工人噪声性听力损失的联系

目的探讨职业性噪声暴露工人外周血淋巴细胞热休克蛋白60（Hsp60）和70（Hsp70）表达水平与噪声性听力损失的关系。方法采用横断面流行病学研究,选取117名噪声暴露作业工人进行听力测试,分为听力损失组和听力正常组;运用Western Blot法检测2组外周血淋巴细胞Hsp60和Hsp70水平。结果与正常组相比,高频段和低频段噪声性听力损失组的淋巴细胞Hsp60和Hsp70表达水平差异均无统计学意义（P〉0.05）;校正年龄、性别、吸烟状况、爆震史和累积噪声暴露量等因素后,得到了同样结果;Hsp70的表达水平与累积噪声暴露量呈临界负相关（r=-0.179,P=0.058）;Hsp70与Hsp60水平之间呈显著正相关（r=0.224,P=0.017）。结论外周血淋巴细胞Hsp70和Hsp60的表达水平与高频段或低频段噪声性听力损失无相关;外周血淋巴细胞Hsp70的表达水平可能反映了机体的累积噪声负荷情况;未发现外周血淋巴细胞Hsp60的表达水平与机体的累积噪声负荷有相关性。