Evaluation of noise effects on standard threshold shift employees of technical and professional organization according to the audiogram and sound overall level measurement in Ilam: A cross-sectional study

Abstract

Background: Noise is one of the most prevalent physically harmful factors in working environment which can cause many problems that one of them is hearing loss. Therefore, the aim of this study was to assess occupational exposure with sound (noise) in training workshops of Technical and Vocational Organization of Ilam and to determine the rate of change in hearing threshold of people working in these workshops. Materials and Methods: A cross-sectional study was carried out on 60 people which working in 8 workshops of Technical and Vocational Organization of Ilam which are selected by census report. Demographic data of studied people are collected using a researcher-made checklist and measuring the overall balance of sound level meter set model 450 is used. Changes in hearing threshold of people are assessed using audiometer. Finally, data are analyzed using SPSS 20 by conduct Spearman correlation and Pearson's correlation statistical tests in asignificant level of 0.05. Results: The results show that there have been 8.62 dB change in hearing threshold of the left ear, 8.73 dB in right ear, and 6.74 dB in both ears of studied people averagely. The highest level of sound pressure balance is related to cutting-wood workshop, and the Equivalent exposure level (Leq) is more than national standard level (85 dB) in mosaic, lapidary, and welding workshops. Spearman correlation test shows a significant relationship between the highest level of sound balance in welding workshop (112 dB) and the average total loss (8.15 dB) for both ears (P