The effect of simultaneous exposure to organic solvents and noise on high frequency hearing loss in tire manufacturing company workers

Based on the results of some studies, concurrent exposure to organic solvents and noise in industrial areas can accelerate the amount of hearing loss. The aim of this study was to assess the effect of concurrent exposure to organic solvents and noise on high frequency hearing loss.
This was a cross-sectional analytic study conducted on 1029 tire manufacturing company workers in 2013. After coordination with the factory authorities, required data including demographic, occupational and medical data and also audiometric records were derived from workers medical profile. Finally all gathered data were analyzed using SPSS version 13 software.
After applying inclusion and exclusion criteria, 914 workers entered the study. The results of this study showed that, the workers including group 4 (workers exposed to impermissible levels of noise and organic solvents) had more severe high frequency hearing loss in comparison to group 1 (workers with no exposure to impermissible levels of noise and organic solvents) (OR= 1.74, 95% CI: 1.15-2.63) and the hearing loss was significant even after modification by logistic regression analysis.
Our study showed that the workers exposed to impermissible levels of noise and organic solvents had higher levels of high frequency hearing loss in comparison to workers with no exposure to impermissible levels of noise and organic solvents, thus we propose that workers with co-exposure to impermissible levels of organic solvents and noise may be benefited from shortening the interval between periodic audiometric evaluation.