Combined exposure of toluene and noise exacerbate hearing loss in male workers
WANG Lu;JIAO Jian-dong;MA Qian-qian;Wuxi Municipal Center for Disease Control and Prevention;
Objective To investigate the risk of hearing loss among workers exposed to toluene and noise at the same time. Methods 167 workers who were simultaneously exposed to toluene and noise were selected as experimental group,153 workers exposed to noise only as control group Ⅰ,and 160 administrative personnnels of the same company as control group Ⅱ. Individual sampling techniques were performed to measure toluene and noise exposure levels in the survey. Interview and questionnaire methods were used to obtain demographic and working history information,besides general physical examinations,pure tone air conduction threshold audiometry between 0. 5 to 6 kHz was performed as well. Hearing loss effects of noise and toluene and their combination were evaluated. Results The prevalence of high-frequency hearing loss in experimental group( 50. 30%) was much greater than that of control group Ⅰ( 37. 25%) and control group Ⅱ( 11. 25%),the prevalence of speech-frequency hearing loss was 4. 79% which was no significantly different( P 0. 05) with that of control group Ⅰ( 2. 61%). The mean hearing thresholds shift in experimental group and control group Ⅰ started to increases at 3 kHz,especially at higher frequencies,and reached the maximum at 6 kHz,the difference was significant( t = 5. 54,P 0. 01). Multivariate logistic regression analysis showed that the control groap I and the experimental group had an esimated risk 3. 96 times and 7. 48 times than control group Ⅱ,respectively. The OR values in each group increased evenly( χ2= 0. 06,P = 0. 81),and job seniority( OR = 1. 11) was an independent risk factor of high-frequency hearing loss. Conclusion The results suggested that combined exposure of noise and toluence can exacerbate high frequency hearing loss in male workers,but there seems no significant effect on speech frequency hearing loss.