Hearing loss risk from exposure to shooting impulses in workers exposed to occupational noise

Abstract

The effect of shooting impulses on hearing was analysed in 150 professional forest workers exposed to noise from chain saws. The exposure to shooting impulses (Lesi) was designed to take into account the peak levels of shooting impulses, their number and use of hearing protectors. Hearing loss was dependent on Lesi even after allowing for the age of subjects and their exposure to chain saw noise. Hearing threshold levels were compared between pairwise matched groups with high and low Lesi. Proper matching was achieved for age, chain saw noise, salicylate consumption, blood pressure, cholesterol, smoking and vibration-induced white finger symptoms. The workers with high Lesi had 9 dB greater hearing loss at 4 kHz and 10 dB greater hearing loss at 8 kHz than those with low Lesi, the difference being significant at P < 0.05 level. In evaluation of noise-induced hearing loss the exposure to shooting impulses from different calibre weapons should be determined since they increase the extent of hearing loss. The present study describes the Lesi method which more accurately evaluates the harmful effects of shooting noise impulses on hearing.

Prolonged exposure to gunfire noise among professional soldiers.

“…With all types of noise, the adverse effects on hear- the total energy of noise (27), and the equ al ene rgy principle has been proposed also for the risk assessment of weapon impulses (17). Damage risk cr iteria proposed for weapon impulses are based on the duration and numb er of impul se s ( 13,26) and also on the hear ing protection employe d (6,23) .…”

“…On the other hand, there are only a few studies on the qualities and accumulated numbers of different shots fired by men during their mandatory milit ary serv ice or career ( 11,12). In addition, the estimation of ex posure to shooting impulses has be en difficult since onl y few feas ible sugg es tions ha ve been introduced to assess the co mplex expo sure to shooting impulses from weapons of different calibe r (13,14). ------------Impulse noise appears to have a detrimental effec t on hearing after a fairl y short period of exp osure , and hearing loss increases rapidly during the fir st few years (3, II ).…”

“…Th e ex pos ure to shooting impulses , in addition to the exposure to stea dy noi se, has been recently studied in a gro up of fores t work ers (13). In this study a multivari ate mod el was introduced for estim ating exposure to shooting impul ses (13).…”

“…Th e ex pos ure to shooting impulses , in addition to the exposure to stea dy noi se, has been recently studied in a gro up of fores t work ers (13). In this study a multivari ate mod el was introduced for estim ating exposure to shooting impul ses (13). On the oth er hand, no recent study exists in which a sys tematic collection of long-term exposure data has been combined with audiometric data to evaluate aud itory hazards in a larger population of profe ssion al so ldiers.…”

“…The attenuation of earplug-type hearing protectors was estimated on the basis of earl ier studies to be 10 dB for large-caliber weapons, 15 dB for assault rifles and pistols , and 20 dB for leisure-time shooting. The attenuation of earmuffs was estim ated to be 5, 20, and 25 dB, respectively (6,7,10,13,17,(23)(24)(25)(26). All officers rated thei r habits of wearing hearing protectors using the following four-grade index: 1 = practically never; 2 = occasionally; 3 = frequentl y; 4 =constantl y.…”