Context: Hearing loss (HL) is a major health concern among military personnel due to noise from shooting, blasts, military vehicles, and noisy training environments. Nevertheless, one's exposure can be partially reduced by using personal protective equipment (PPE). The aim of this study is to estimate the prevalence of HL among military personnel, to analyse associations between HL and self-reported occupational and leisure noise exposure, and use of PPEs.
Materials and methods: A cross-sectional study was conducted among 150 military personnel during their routine medical examinations. First, all participants filled in a questionnaire about their exposure to noise and later the respondents went through an audiometric test. The diagnostic criteria for slight, moderate, and severe HL was HL of 25-40, 41-60, and >60 dB at 4 and 6 kHz, respectively. The associations between noise exposure and HL were studied with multinomial logistic regression analysis.
Results: The prevalence of slight to severe HL in high frequencies (4 and 6 kHz) among study participants was 62.7%. Nevertheless, the majority of it was slight, as the prevalence of severe HL was 9.3%. The prevalence of any kind of HL was highest in the Navy and the prevalence of severe HL was highest in the Central Command Units. The relative risk ratios (RRRs) for HL were higher among those who had been working for a long time in a noisy environment, working with noise-producing equipment, driving in a PASI or a Bandvagn or had been shooting with blanks at least once per week. It also appeared that military personnel who had HL, reported tinnitus more often. Respondents' previous health problems, music-listening habits, and amount of exposure to loud noise in non-military environments were not independently associated with HL, but in several cases it increased the RRRs together with military exposure. We also found significantly more frequent HL among those never using PPEs.
Conclusion: HL loss was more prevalent among personnel who are more often exposed to military noise, especially among those who never use PPEs. The effect was enhanced by leisure time noise, but it was not independently associated to HL.
Keywords: Active service; audiometry; hearing protection; noise exposure.