A survey of hearing loss in Army aircrew.

Military aircrew are exposed to excessive noise at work, with the concurrent risks of acquiring Noise Induced Hearing Loss (NIHL). Past studies have related aircrew NIHL to a variety of factors; however, no clear causal relationship has been shown. The difficulty of establishing NIHL due to flying remains when many other confounders are present, especially age and exposure to firearms noise in the military environment. A cross sectional prevalence study of hearing loss in Army Air Corps aircrew has been undertaken. One hundred and twenty one aircrew who had more than ten years flying experience were studied and the results show that there appears to be a threshold shift in excess of that expected from the ISO levels for otologically normal males of the same age. The hearing threshold shift was found to correlate with the number of years flying and aircrew age, with the number of flying hours being less significant.