@article{ref1,
title="A cross-sectional study of hearing thresholds among 4627 Norwegian train and track maintenance workers",
journal="BMJ open",
year="2014",
author="Lie, Arve and Skogstad, Marit and Johnsen, Torstein Seip and Engdahl, Bo and Tambs, Kristian",
volume="4",
number="10",
pages="e005529-e005529",
abstract="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. <br><br>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. <br><br>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. <br><br>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.<p /> <p>Language: en</p>",
language="en",
issn="2044-6055",
doi="10.1136/bmjopen-2014-005529",
url="http://dx.doi.org/10.1136/bmjopen-2014-005529"
}