Hearing status among Norwegian train drivers and train conductors

Background: There is a general perception that train drivers and conductors may be at increased risk of developing noise-induced hearing loss. Aims: To study job-related hearing loss among train drivers and train conductors. Methods: Audiograms from train drivers and train conductors were obtained from the medical records of the occupational health service of the major Norwegian railway company. The results were compared with audiograms from an internal control group of railway workers and an external reference group of people not occupationally exposed to noise. The monaural hearing threshold level at 4kHz, the mean binaural value at 3, 4 and 6kHz and the prevalence of audiometric notches (≥25 dB at 4kHz) were used for comparison. Results: Audiograms were available for 1567 drivers, 1565 conductors, 4029 railway worker controls and 15 012 people not occupationally exposed to noise. No difference in hearing level or prevalence of audiometric notches was found between study groups after adjusting for age and gender. Conclusions: Norwegian train drivers and conductors have normal hearing threshold levels comparable with those in non-exposed groups.