Hypoacusis among the Polar Eskimos of northwest Greenland

Audiological tests were conducted on 188 Polar Eskimos (75 males and 43 females) in small, remote, nonindustrialized settlements of Northwest Greenland. Most males of this small Eskimo tribe hunt regularly for food using rifles and shotguns. The means of the pure tone hearing thresholds indicated that 77% of the males in the population sample had a hearing loss (greater than 25 dB HL) in the high frequency range (above 2,000 Hz), in one or both ears. Also, 73% of the males had bilateral hearing losses (greater than 25 dB HL), and 73% had hearing thresholds greater than or equal to dB in one or both ears. A high frequency hearing loss was found in 46% of the males of the younger age groups (less than or equal to 40 years), mainly in the 3,000 to 8,000 Hz range, with the mean loss gradually extending to 2,000 and 1,000 Hz, and increasing in severity with age. The mean pure tone thresholds of 6- to 60-year-old female Polar Eskimos (who do not hunt with firearms) were generally within normal limits over the entire audiometric frequency range for the younger groups, and increased with age to the mild hearing loss range. Among the females, 35% had a hearing loss (less than 25dB HL) in the high frequency range (above 2,000 Hz) in one or both ears, and 21% had thresholds of greater than or equal to 50 dB in one or both ears. Conductive hearing losses in the low frequency range were not widespread among the males or females of this survey. The findings of this study suggest: (1) The high incidence of age-related hearing loss among the Polar Eskimo males is the result of frequent exposure to high intensity, impulse firearm noise, which is the major source of noise for this population, in an otherwise "noise-free" environment. (2) The primary noise-induced permanent threshold shift among Polar Eskimo hunters occurs in the age range of 10-40 years, and increases slowly thereafter, mainly as a result of continual noise exposure and presbyacusis. It is recommended that ear protectors and a comprehensive hearing conservation/rehabilitation program be provided for the Polar Eskimo population at once in order to prevent further hearing impairment and to rehabilitate those persons presently suffering from hearing loss.