PT  - JOURNAL ARTICLE
AU  - Arve Lie
AU  - Marit Skogstad
AU  - Torstein Seip Johnsen
AU  - Bo Engdahl
AU  - Kristian Tambs
TI  - A cross-sectional study of hearing thresholds among 4627 Norwegian train and track maintenance workers
AID  - 10.1136/bmjopen-2014-005529
DP  - 2014 Oct 01
TA  - BMJ Open
PG  - e005529
VI  - 4
IP  - 10
4099  - http://bmjopen.bmj.com/content/4/10/e005529.short
4100  - http://bmjopen.bmj.com/content/4/10/e005529.full
SO  - BMJ Open2014 Oct 01; 4
AB  - Objective Railway workers performing maintenance work of trains and tracks could be at risk of developing noise-induced hearing loss, since they are exposed to noise levels of 75–90 dB(A) with peak exposures of 130–140 dB(C). The objective was to make a risk assessment by comparing the hearing thresholds among train and track maintenance workers with a reference group not exposed to noise and reference values from the ISO 1999. Design Cross-sectional. Setting A major Norwegian railway company. Participants 1897 and 2730 male train and track maintenance workers, respectively, all exposed to noise, and 2872 male railway traffic controllers and office workers not exposed to noise. Outcome measures The primary outcome was the hearing threshold (pure tone audiometry, frequencies from 0.5 to 8 kHz), and the secondary outcome was the prevalence of audiometric notches (Coles notch) of the most recent audiogram. Results Train and track maintenance workers aged 45 years or older had a small mean hearing loss in the 3–6 kHz area of 3–5 dB. The hearing loss was less among workers younger than 45 years. Audiometric notches were slightly more prevalent among the noise exposed (59–64%) group compared with controls (49%) for all age groups. They may therefore be a sensitive measure in disclosing an early hearing loss at a group level. Conclusions Train and track maintenance workers aged 45 years or older, on average, have a slightly greater hearing loss and more audiometric notches compared with reference groups not exposed to noise. Younger (<45 years) workers have hearing thresholds comparable to the controls.