Investigation on health condition of female telephone operators exposure to speech frequency noise

  Objective  To evaluate health conditions of female telephone operators answering hotline in a state-owned enterprise and offer targeted protective suggestion.

  Methods  From 2017 to 2019, the noise level in the workshop for answering the hotline of a state-owned enterprise was measured. Totally 60 female telephone operators answering for hotline and 60 female office clerks without any occupational exposure to hazards in the same company were examined.

  Results  The noise level(L_{ex, 8 h}) in this workshop was 55.3-78.6 dB(A), mainly concentrated in 500-3 000 Hz; the noise level inside the earphone of female operators was 62.7-88.9 dB (A), mainly concentrated in 500-2 000 Hz, which belonged to the non-steady speech frequency noise. The prevalence of self-reported fatigue, memory loss, loss of appetite, body aches, difficulty in sleeping, amblyacousia, and menstrual disorder among these female operators was significantly higher than that of office clerks respectively (P < 0.01 or P < 0.05). Both high and speech frequency hearing thresholds of female operators increased significantly and the abnormality of hearing loss was higher(P < 0.01). Prevalence of ECG abnormality in total, sinus bradycardia, sinus arrhythmia and inadequate myocardial blood supply of operators was increased significantly compared with that of the office clerks respectively(P < 0.01 or P < 0.05). The prevalence of hypotension, dysarteriotony, increased serum triglyceride and total cholesterol, and dyslipidemia among female operators was significantly higher (P < 0.01 or P < 0.05). The abnormality of hearing loss and hypotension of female operators increased gradually with increment of working time(P < 0.05).

  Conclusions  Long-term exposure to speech frequency noise could induced hearing loss mainly characterized by high frequency hearing threshold increase, subjective symptoms mainly characterized by neurasthenic syndrome, and abnormality of ECG, blood pressure and blood lipids. Female telephone operators occupationally exposed to speech frequency noise should be strengthened the personal protection.