Self-reported elevated blood pressure in army officers with hearing loss and gunfire noise exposure.

The association of noise-induced hearing loss from gunfire noise with the occurrence of elevated blood pressure was investigated with screening audiometric measurement results and a questionnaire in a randomly selected group of 699 army officers. After age correction, hearing was found to be deteriorated (i.e., more than 20 dB at all of the measured frequencies) in 352 (50.4%) subjects. Of the 699 officers, 535 (76.5%) reported normal and 164 (23.5%) reported elevated blood pressure. In 122 (17.5%), elevation was permanent and verified by a physician. The occurrence of elevated blood pressure showed a highly significant correlation with severity of hearing loss (chi-square = 25.4; p < 0.001), but not with exposure to gunfire noise. Self-reported hypertension seemed to be associated with severity of impulse noise-induced hearing loss, but not with the amount of gunfire noise exposure. Thus, the present study does not support the suggestion that there exists a simultaneous correlation between impulse noise exposure, noise-induced hearing loss, and self-reported elevated blood pressure.

Prolonged exposure to gunfire noise among professional soldiers.

OBJECTIVES: The aim of the study was a retrospective assessment of the exposure of professional soldiers to impulse noise from gunfire. METHODS: A questionnaire on noise exposure and use of hearing protectors was administered to a stratified random sample of 699 army officers (mean age 39.8 years) with an average of 18 years of exposure to shooting noise. For a comparison of the number of shots from different weapons, the peak sound pressure levels of shots were adjusted in relation to one pistol shot according to the equal energy principle. Total exposure time was estimated with the equal energy principle, the number of shots from different weapons, the energy levels of different shots, the effectiveness of hearing protection, and the distance from the noise source being taken into account. RESULTS: Rifles, shotguns, and pistols were the predominant exposure sources. Impulse noise exposure averaged 164,183 shots from different weapons. After adjustment to the energy level of one pistol shot, the average was 78,000 personally fired shots. The total shooting noise exposure averaged 218,000 adjusted shots. Translated into exposure to steady noise of 85 dB(A) for 40 h a week, the exposure to noise from personally fired shots equaled an exposure time of 22.0 years and the total exposure averaged 61.0 years. The heaviest exposure occurred during the first 10-15 years of the men's careers. CONCLUSIONS: Exposure to gunfire noise among professional soldiers is high enough to cause severe hearing deterioration already at early career stages if effective hearing protectors are not worn at all times on shooting occasions.

Hearing loss and handicap of professional soldiers exposed to gunfire noise.

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