Objective To evaluate auditory dysfunction in workers exposed to low doses of solvent mixtures.
Methods 77 workers exposed to solvents as well as a control group of 84 non-exposed individuals were studied. Fourteen solvents were measured, including toluene, xylene, and n-hexane. Pure tone audiometries were performed at 125 Hz to 8 KHz, as well as brainstem evoked response.
Results In the exposed group, subjects’ hearing decreased in the measured frequencies, in both ears. Robust multiple linear regression models for frequency means between 125 Hz and 8 KHz, for the left ear R2 = 33.3%, exposed β = 4.1 (p<0.001) and for the right ear R2 = 38%, exposed β = 4.8 (p<0.001), adjusted by age, chronic pathologies and environmental noise exposure. There was major latency in waves III and V and in intervals I-V and I-III (p<0.05), in both ears, adjusted for age and chronic pathologies.
Conclusions It is likely that low exposures to solvent mixtures affect hearing and their central pathways. It is important to elucidate whether this affection could indicate incipient ototoxicity and neurotoxicity.