Prevalence and Pattern of Noise-induced Hearing Loss in Tile and Ceramic Industry

Noise-induced hearing loss is considered as one of the most common occupational problems. Audiometric pattern of NIHL is different in various workplaces. This study was designed to find the prevalence and pattern of hearing loss in tile and ceramic industry. This was a cross-sectional study conducted on 853 tile and ceramic workers in Yazd, Iran. Plants were selected by simple random sampling from all tile and ceramic plants in Yazd. Hearing thresholds were recorded at 500, 1000, 2000, 3000, 4000, 6000, and 8000Hz. Hearing loss at each frequency was defined as hearing threshold higher than15 dB-HL. Data were analyzed by SPSS (ver. 20) using Student’s -test, chi-square test, and ANOVA. The audiometric frequency mostly affected by noise in both ears was 6000 Hz, followed by 4000 Hz and 3000 Hz. Prevalence of unilateral notch in one of the frequencies (3000, 4000, or 6000 Hz) was 18.6% and bilateral notch was observed in 3.9% of the subjects. Mean (±SD) hearing threshold at high frequencies (3000, 4000, and 6000 Hz) in right and left ears was 17.23 (±0.48) and 16.81 (±0.48) dB-HL, respectively and the difference was not significant (P>0.05). Most of the subjects suffered from slight high-frequency hearing loss. NIHL was common in tile and ceramic workers, although most workers suffer from slight and mild hearing loss. Audiometric notch was not frequent in this industry.