高强度低频电磁辐射暴露人群外毛细胞功能评价及其影响因素分析

Analysis on outer hair cells hazards from occupational exposure to low frequency electric and magnetic fields and magnetic fields and its related factors

目的:了解高强度低频电磁辐射作业环境中作业人群的职业暴露现状和内耳功能变化及其影响因素。方法:以某高强度低频电磁辐射作业环境中的502例作业人员为调研对象。应用电磁辐射场强仪和噪声分析仪对作业现场不同工作岗位的作业环境进行电磁辐射强度测试和噪音测试,观察作业环境的电磁污染和噪声污染现状;对调研对象进行问卷调查和畸变产物耳声发射(DPOAE)、纯音测听(PTA)检测,从总体样本人群中筛选出DPOAE检测中2个或2个以上频率未通过的100例作为观察组,DPOAE检测完全通过者100例作为对照组。对纯音测听检测中连续两个频率纯音听阈>20 dB HL进行ABR检测。采用非条件logistic回归分析方法进行DPOAE影响因素筛选。结果:作业场所的电场强度在21～38 KV/m,超出国家标准。噪音强度在52～65 dB HL范围内,在安全范围内。问卷调查结果提示观察组中头痛、失眠、耳鸣的发生率明显高于对照组。DPOAE检测显示观察组的通过率和幅值低于对照组,提示该频段电磁辐射暴露可能会引起外毛细胞轻度、散在的改变。多因素logistic回归分析显示,DPOAE未通过发生的促进因素是接触电磁辐射(OR=40.22)、日辐射暴露时间长(OR=27.05)、工龄长(OR=1.67)。保护因素是使用电磁辐射防护措施(OR=0.388)。结论:该人群暴露于超标的电磁辐射环境中,DPOAE的未通过率以及其幅值下降远高于正常人群,接触辐射、工作时间、每日工作时间可能是导致DPOAE未通过发生的重要危险因素,而使用电磁辐射防护措施是保护因素。

Objective：To explore the function of outer hair cells and its influencing factors in the workers of occupational exposure to 10w frequency electric and magnetic fields. Method： 502 high-strength LF EMFs-exposed workers were taken as the study subjects. The field intensity indicator and noise analyzer were employed for the examination of the electromagnetic energy intensity and noise value at the working sites. Self-administered ques- tionnaires were adopted. Universal hearing screening by distortion product otoacoustic emission （DPOAE） and pure tone audiometry（PTA） were done. 100 workers who had abnormal POAE were taken as the observation group and 100 workers who had normal DPOAE were taken as the control group. The workers need be confirmed with ABR testing when the pure tone threshold of two consecutive frequencies were above 20 dB HL or DPOAE detection in any frequency did not pass. Multiple factor analysis with logistic regression was performed for the risk factors. Resuit：The average electric power density in job locations was 21-38 KV/m, which was higher than na- tional standard（〈5 kv/m）. Average n0ise-level in job locations was 52-65 dBHL, which was within the standard （〈85 dB（A）. Questionnaire presented that low frequency electric and magnetic fields might increase the incidence of headache, insomnia and tinnitus in the observed group. The incidence of abnormal DPOAE was higher in the subjects of the observed group（P〈0.01）. At 676, 933, 3 616, 5 130, 7 253 Hz, the DPOAE amplitudes of the observed group workers were significantly lower than the control group. Multivariate analysis showed that the risk factors of abnormal DPOAE included exposure of EMF, length of service, daily exposure time, conservatory meas- ures might be protective factors. Conclusion：The changes of DPOAE indicated that the exposure to low frequency electric and magnetic fields had a subtle, discreet and localized impairing effects on outer hair cells. Exposure oflow frequency electric and magnetic fields, length of service, daily exposure time might be risk factors, conservato- ry measures might be protective factors.