title: Does diving affect the hearing of Asian military divers? A study in the Republic of Singapore Navy.
abstract: OBJECTIVE
  This study examined whether military diving during a National Serviceman's two-year term of service affected his hearing threshold levels.
  
  
  METHODS
  A retrospective cohort study was designed to examine the hearing thresholds of divers (mean age 20.9 years) who enlisted between 2001 and 2010 (n = 748). Their pre-enlistment and pre-discharge audiograms were collected. All made dives using scuba dive sets, averaged 200 dives over two years and depths of 30 meters of sea water/msw or less.
  
  
  RESULTS
  The divers' hearing levels in the left ear were not affected except for a marginal decrease in hearing level at the 2kHz level. There was a marginal decrease in hearing level in 0.5, 1 and 2 kHz in the right ear. These changes are physiologically insignificant. There were more low-frequency (0.5, 1 and 2 kHz) changes compared to high-frequency (4 and 8 kHz) changes in both ears, with a larger number of changes noted in the right ear, as compared to the left. However, no diver had a hearing threshold increase greater than 20dB or exceeded the hearing threshold levels required of military divers.
  
  
  CONCLUSIONS
  There was no decrease of clinical significance in hearing function of the Republic of Singapore Navy national serviceman naval divers after diving for two years.
authors.forename: Jeremiah
authors.initials: J
authors.lastname: Chng
authors.forename: Gregory
authors.initials: G
authors.lastname: Chan
authors.forename: K C
authors.initials: KC
authors.lastname: Tang
mesh_terms: D001299:Audiometry; D001309:Auditory Threshold / Q000502:physiology*; D004242:Diving / Q000009:adverse effects* / Q000502:physiology / Q000706:statistics & numerical data; D006309:Hearing / Q000502:physiology*; D006311:Hearing Disorders / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008889:Military Personnel / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012846:Singapore; D055815:Young Adult