Reference data for evaluation of occupationally noise-induced hearing loss.

Relevant reference data are required in order to determine the effect from occupational noise exposure on hearing. Pure-tone averages (PTA) of hearing threshold levels simplify the evaluation for audiometric frequencies typically affected by noise. The present study provides reference data of high frequency (HF) PTA over 3, 4 and 6 kHz for a general adult population, aged from 20 to 79 years, not exposed to hazardous occupational noise. The results are presented as statistical distributions of HF PTA values as functions of age, and as prevalence of different degree of HF PTA in the age groups 20-29, 30-39, 40-49, 50-59, 60-69 and 70-79 years.