Epidemiology of occupational noise-induced hearing loss (ONIHL) in Poland

Noise-induced hearing loss is a major health risk worldwide. In Europe about 35 million people are exposed to detrimental noise levels (> 85 dB-A) in industrial plants, and occupational deafness is a leading occupational compensible disease in the all countries; it is an insidious slow process that develops over a period of approximately 10 to 20 years. Accordingly to the latest estimations, more than 650,000 workers (of a total 5 million employed in industry) are put at risk in Poland. Despite progress in engineering approaches for reducing noise in the work environment and in improving hearing conservation programs (both the technical and medical) the ONIHL still remains a common and costly disability. The aim of this study is presentation of the most recent data on the incidence of ONIHL in Poland in the years 1992-2002 considered to be a base for implementing the effective prophylactic activities. The analysed data were derived from the central state register which collects all cases of occupational diseases recognized in the country. The highest incidence was found in such key industrial branches as coal mining, iron and steel, metallurgical and transport equipment; majority of cases were observed in southern and western provinces, mainly in the Silesian district, known from the significant concentration of noisy enterprises. The most affected were those workers aged 50-59 years and exposed to noise for over 20 years. More than 30 new cases of ONIHL were identified in the years 1992-1998 annually per 100,000 employees, and with beginning 1999 the rate was significantly decreased to 10 cases in 2002. One may presume that it results from the set up of national program of hearing preservation introduced in 1999 with obligatory pre-employment and follow-up pure-tone audiometry, as well as with hearing screening by means of the otoacoustic emissions.