Zhao Jing, Sun Jianjun, Jia Zhonghong, Diao Mingfang, Liu Yang, Tian Fangjie
Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi. 2013 Nov;27(22):1247-51.
To explore the function of outer hair cells and its influencing factors in the workers of occupational exposure to low frequency electric and magnetic fields.
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 questionnaires 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.
The average electric power density in job locations was 21-38 KV/m, which was higher than national standard (< 5 kv/m). Average noise-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, 3616, 5 130, 7253 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 measures might be protective factors.
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 of low frequency electric and magnetic fields, length of service, daily exposure time might be risk factors, conservatory measures might be protective factors.
探讨职业性接触低频电场和磁场的工人中外毛细胞的功能及其影响因素。
选取502名高强度低频电磁场暴露工人作为研究对象。使用场强仪和噪声分析仪检测工作场所的电磁能强度和噪声值。采用自填式问卷。通过畸变产物耳声发射（DPOAE）和纯音听力测试（PTA）进行普遍听力筛查。将100名DPOAE异常的工人作为观察组，100名DPOAE正常的工人作为对照组。当两个连续频率的纯音阈值高于20 dB HL或任何频率的DPOAE检测未通过时，工人需进行听性脑干反应（ABR）测试确认。对危险因素进行logistic回归多因素分析。
工作场所的平均电功率密度为21 - 38 KV/m，高于国家标准（< 5 kv/m）。工作场所的平均噪声水平为52 - 65 dBHL，在标准范围内（< 85 dB(A)）。问卷调查显示，低频电场和磁场可能增加观察组头痛、失眠和耳鸣的发生率。观察组受试者中DPOAE异常的发生率更高（P < 0.01）。在676、933、3616、5130、7253 Hz时，观察组工人的DPOAE幅值明显低于对照组。多因素分析表明，DPOAE异常的危险因素包括电磁场暴露、工龄、每日暴露时间，防护措施可能是保护因素。
DPOAE的变化表明，暴露于低频电场和磁场对外毛细胞有细微、隐匿和局部的损害作用。低频电场和磁场暴露、工龄、每日暴露时间可能是危险因素，防护措施可能是保护因素。
