SURVEILLANCE OF NOISE-INDUCED HEARING-LOSS IN TAIWAN, ROC - A REPORT OF THE PRESS-NIHL RESULTS

Background. To understand the extent of noise-induced hearing loss (NI HL) among noise-exposed workers, an ongoing public health surveillance system (Program to Reduce Exposure by Surveillance System or PRESS-NI HL) was established in Taiwan in 1995 to monitor the prevalence of NIH L. Methods. A total of 9,535 noise-exposed (> 85 dBA) workers were rec ruited into PRESS-NIHL from January to June 1995. Each received a peri odic annual audiometric examination at 1 of 73 well-qualified audiomet ric examination rooms in accredited hospitals, Among those examined, 9 ,463 audiograms were acceptable for evaluation to determine the severi ty of NIHL at 4K Hz. Results. The mean hearing threshold at 4K Hz was 36.8 dB among male workers and 29.7 dB among female workers. The mean hearing loss at 4K Hz of male workers was higher than that of female w orkers. Among both men and women, hearing ability was found to decreas e with increasing age. A total of 3,216 (34.0%) workers were found to have NIHL, with a hearing threshold higher than 40 dB (NIHL) in either one or both ears. Among these workers, 1,886 (19.9%) had mild NIHL (h earing threshold between 40 and 55 dB) and 1,330 (14.1%) had severe NI HL (hearing threshold above 55 dB) in either one or both ears, The pro portion of severe NIHL was higher in certain industries, including con struction (38.6%), ship building/repairing (19.2%), and weapon manufac turing (13.6%). Conclusion. This surveillance system for NIHL is one o f the first surveillance systems in the world established to monitor a nd control NIHL in the setting of industrial hygiene and occupational disease prevention, Our finding of a high prevalence of NIHL in certai n industries will trigger immediate actions to control noise hazard, w hich in turn will provide better protection for noise-exposed workers. (C) 1998 Academic Press.