Table 1

Background data

Train driverTrain conductorBus driverTrain maintenanceTrack maintenanceTraffic controllerOthersTotal
Number
 First audiometry156813197131506213255418489640
 Last audiometry145412547121339193665922839640
Age, mean (years)
 First audiometry37.133.044.139.538.238.040.238.3
 Last audiometry47.843.750.850.150.649.749.248.8
Sex (% men)
 First audiometry96.665.093.896.398.677.382.788.7
 Last audiometry95.465.093.896.498.579.785.788.7
 Daily noise exposure, dB(A)
LAEq, 8h70–8070–8570–7585–8685–86<70unknown
Better ear HTL346, dB (SD)
 First audiometry10.2 (9.8)8.0 (7.6)16.8 (13.1)14.5 (12.1)12.7 (11.6)10.3 (9.9)13.6 (11.5)12.3 (11.2)
 Last audiometry17.3 (14.1)14.1 (12.5)22.0 (15.1)22.3 (15.8)22.0 (15.9)17.5 (13.6)19.3 (14.5)19.3 (14.9)
Better ear HTL 0.5124, dB (SD)
 First audiometry6.7 (5.8)5.7 (4.9)11.1 (7.2)9.7 (7.1)8.3 (6.6)6.9 (5.8)8.9 (6.3)8.1 (6.5)
 Last audiometry9.6 (7.5)8.3 (7.2)13.2 (8.3)13.2 (8.8)12.2 (8.9)9.7 (7.7)11.3 (7.7)11.1 (8.2)
  • Sex, age, occupational noise exposure and hearing by occupation (mean 3, 4 and 6 kHz and mean 0.5, 1, 2 and 4 kHz, better ear).

  • HTL, hearing threshold.