Hearing loss among Fasa sugar factory workers’, Fars Provincre, Iran (2016)

Background: Hearing loss induced by noise is one of the well-known and main health problems of occupational exposures. As a result, the current study sought to examine the association between age, working experience, and smoking status and hearing loss among sugar factory workers. Materials and Methods: This cross-sectional study was conducted in 2016 among 270 workers of a sugar factory in Fasa, Iran. Workplace noise was measured based on ISO 9612 by using Casella-Cel (model 450) sound level meter. Pure-tone audiometry test was performed by audiometry device (AC 40). Data were analyzed by SPSS software using independent two-sample t-test to compare the mean scores of hearing threshold in different age and work experience groups. Results: Out of 270 workers at the factory, 155 were exposed to noise exceeding 85 dB. Based on sound pressure level measurements, the major noise producing parts of the factory were steam boiler, furnace, turbine, drying, and welding sections. The results showed that the average hearing threshold at 4000 Hz in both ears was higher than other frequencies. This was followed by the hearing thresholds at frequencies of 8000 and 2000, 500, 1000 and 250 Hz, in that order. Noise had the strongest effect in the mentioned frequencies (P < 0.05). Conclusions: The results indicated that smokers and older people were at higher risk of hearing loss compared to non-smokers and younger workers. Thus, it is suggested that policy makers minimize hearing loss among workers by taking noise controlling measures in departments that are exposed to excessive noise, training workers, conducting regular periodic hearing tests, and establishing a regular work-rest cycle.