Hearing loss in divers: a 6-year prospective study

Abstract

Occupational diving is associated with hearing loss, but the cause is disputed. Our aim was to follow a cohort of divers through the first 6 years of their career in order to look for evidence of permanent threshold shift associated with diving activity, occupational noise exposure or acute injuries. Hearing was measured by pure tone audiometry in 67 participants at a basic course for working divers. Hearing thresholds were adjusted for age (ISO 7029). The subjects were examined and interviewed by an otologist. Additional medical and exposure data were recorded in questionnaires and personal logbooks. The procedure was repeated after 3 and 6 years. None of the subjects suffered inner ear barotrauma or inner ear decompression sickness during follow-up. Middle ear barotrauma was common. The prevalence of subjective hearing difficulties increased during follow-up, and there was a significant threshold shift at 4 kHz (mean 2.6 dB, 95% confidence interval 0.9-4.3 dB). Both subjective and objective hearing loss was associated with occupational noise exposure, but not with diving frequency or with a history of middle ear barotrauma. In the absence of manifest inner ear barotrauma or inner ear decompression sickness, noise seems to be the most important cause of long-term hearing loss in occupational divers. This study did not find evidence of long-term hearing loss caused by uneventful diving per se.

Prevalence and Risk Factors for Hearing Loss in Chilean Shellfish Divers

“…In contrast to the generally assumed negative impact of smoking on hearing [2728], we found an inverse relationship. A similar relationship was discovered in a prospective study among European sport divers [10]. One might argue that, at least in our study, smokers were younger and thus, the impact of age on hearing loss is reflected also in the association between smoking and hearing loss.…”

“…These similarities suggest that long-term exposure to risk factors in the work environment of shellfish divers can have a great influence on sensorineural hearing loss. Whether this hearing loss might is a result of the noise in the diver’s working environment or the diving itself has been discussed in several studies [6101112]. In contrast to the generally assumed negative impact of smoking on hearing [2728], we found an inverse relationship.…”

“…These conditions were adequate for an audiometric screening, considering that the purpose of this study was not to calculate the percentage of hearing loss. Other factors not included in this study were possible noise exposure in motorboats and the presence of chronic diseases that can affect the inner ear [10122529].…”

“…Likewise, decompression sickness of the inner ear, caused by nitrogen bubbles that obstruct blood vessels supplying the inner ear, might cause hearing loss [789]. Furthermore, noise-induced hearing loss due to motor noise has been described mainly among Scuba divers [101112]. Overall, only a few studies have investigated the association between diving and hearing loss, and the results have been inconclusive [1011121314].…”

“…Furthermore, noise-induced hearing loss due to motor noise has been described mainly among Scuba divers [101112]. Overall, only a few studies have investigated the association between diving and hearing loss, and the results have been inconclusive [1011121314]. None of the studies were carried out among artisanal shellfish divers using Hookah technique.…”