Hearing loss as a predictor for hearing protection attenuation among miners.

OBJECTIVE

This study investigated risk factors for poor earplug fit, with a focus on the association between hearing loss and personal attenuation ratings (PARs).

METHODS

Earplug fit was assessed by obtaining PARs using a real ear at attenuation threshold (REAT) system. Hearing loss was assessed using the unoccluded hearing thresholds measured during the REAT testing and the results of a speech-in-noise test. Potential predictors of PARs were modelled using both simple and multiple linear regression. Hearing loss was the primary predictor of interest.

RESULTS

Data were collected from 200 workers at ten above-ground mining sites in the Midwestern USA. Workers reported wearing their hearing protection on average 73.9% of the time in a high noise environment (mean 8-hour time-weighted average noise exposure 85.5 dBA, range 65-103 dBA). One-quarter (26.7%) of workers were found to have a hearing loss (hearing threshold ≥25 dB across 1-4 kHz), and 42% reported symptoms of tinnitus. Workers with a hearing loss had a significantly lower PAR than those without a hearing loss (β=-5.1, SE=1.7).

CONCLUSIONS

The results of the adjusted regression models suggest that workers with hearing loss achieved significantly lower PARs than those without hearing loss. This association between hearing loss and hearing protection devices (HPD) fit brings into focus the potential benefit of fit checks to be included in hearing conservation programmes. Workers found to have hearing loss should be prioritised for fit testing, as their hearing impairment may be associated with poor HPD fit.