Table 1.
Age, gender, exposure to noise and hearing loss in train drivers (n = 1567) and conductors (n = 1565) compared with non-exposed railway workers (n = 4029)
| Internal reference | Train drivers | Train conductors | P | |
|---|---|---|---|---|
| n | 4029 | 1567 | 1565 | – |
| Gender (% females) | 29 | 8 | 40 | <0.001a |
| Age, years: mean (SD) | ||||
| Males | 45.8 (8.11) | 46.1 (3.12) | 40.5 (7.11) | <0.001b |
| Females | 38.5 (1.11) | 38.6 (3.11) | 34.2 (2.10) | <0.001b |
| Occupational noise exposure (dBA) | <70 | 70–80+ peak | 70–85+ peak | – |
| Hearing loss (mean 3, 4 and 6kHz binaural, dB) | ||||
| Males | 20.4 | 20.8 | 17.2 | <0.001b |
| Females | 12.1 | 11.5 | 10.3 | <0.001b |
| Adjusted hearing loss (mean 3, 4 and 6kHz binaural, dB)c | 17.5 | 17.7 | 18.0 | NSc |
| Adjusted hearing loss (4kHz, right ear, dB)c | 16.3 | 16.4 | 16.3 | NSc |
| Adjusted hearing loss (4kHz, left ear, dB)c | 17.9 | 18.4 | 18.0 | NSc |
| Prevalence audiometric notch (≥25 dB at 4kHz) (%) | 9.4 | 12.5 | 7.7 | <0.001a |
| Audiometric notch, OR (95% CI)d | 1.0 (Ref) | 1.09 (0.91–1.32) | 1.10 (0.88–1.37) | NSd |
OR, odds ratio; CI, confidence interval; SD, standard deviation; NS, not significant.
aχ2 test.
bAnalysis of variation.
cAnalysis of variation, adjusted for age and gender.
dBinary logistic regression adjusted for age and gender.