Hearing loss and handicap of professional soldiers exposed to gunfire noise

The aim of the study was to investigate the prevalence and degree of hearing loss and other disabling consequences of noise among professional soldiers.

A cross-sectional audiometric survey was combined with a questionnaire study on disabilities in a stratified random sample of 699 army officers (mean age 39.8 years) with long-term exposure to gunfire noise.

In 224 (32%) officers, the hearing threshold was found to be 20 dB or less at all of the frequencies measured (0.5, 1, 2, 3, 4, 6, and 8 kHz). Most of the 475 (68%) subjects with hearing loss belonged to older age categories, but more than one-fourth (26%) of the officers under 30 years of age had a hearing loss. Low frequencies were deteriorated in 110 (16%) subjects. The average of the hearing threshold levels of the frequencies 2 and 4 kHz exceeded 20 dB in 229 (33%) officers. For 347 (49.6%) subjects hearing was normal for their age. The degree of age-corrected hearing loss, especially at low frequencies, correlated highly significantly with exposure. Altogether 220 (32%) men experienced tinnitus, 118 (17%) of them continuously. Tinnitus was the most common among the men with severe or disabling hearing loss. Twenty-four (3.4%) of 699 officers needed sound amplification in noisy environments.

The prevalence of hearing loss in the Finnish Defence Forces seems to have decreased, but a fairly large number of younger men still suffer considerable hearing loss and disabling tinnitus, although the use of hearing protectors has substantially increased during the past 15 years. Most of the subjects experienced communication difficulties in noisy environments.