The association of age, flying time, and aircraft type with hearing loss of aircrew in the Israeli Air Force.
Exposure to aircraft (A/C) noise is considered to be one of the factors which causes permanent hearing threshold shifts among military aircrew. Consequently most studies, dealing with this field of evaluation, fail to focus on the contribution of other elements, especially biological (physiological) ones. We, therefore, decided to evaluate the effect of the subject's age on this process. Audiometric records of 777 aircrew members within the Israeli Air Force were examined. The average age was 27.2 +/- 5.2 years. The individual files were composed of all yearly audiograms from time of recruitment to present, personal information, recorded flight time and type of A/C flown (i.e., rotary-wing and fighter, transport and light fixed-wing aircraft). Hearing loss was studied using two criteria (a. USAF criteria; b. acoustic trauma criteria we devised). The significance of each of the factors was analysed by using uni- and multivariate analysis (Pearson correlation and stepwise multiple regression). A progressive linear correlation between age and hearing loss was exhibited (p less than 0.001). The results suggest that the age of the subject is strongly correlated with values of hearing threshold shift, while A/C type and accumulated time played a minor role.
D000293:Adolescent; D000328:Adult; D000337:Aerospace Medicine; D000367:Age Factors; D000401:Aircraft; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D006317:Hearing Loss, Noise-Induced / Q000209:etiology*; D006801:Humans; D007557:Israel; D008297:Male; D009784:Occupational Diseases / Q000209:etiology*; D013997:Time Factors