Distortion product otoacoustic emission sensitivity to different solvents in a population of industrial painters

Abstract

Objective: To evaluate the ototoxic effect of the exposure to different organic solvents and noise using distortion product otoacoustic emissions (DPOAEs).

Design: The exposure to different solvents was evaluated by measuring, before and at the end of the work-shift, the urinary concentrations of solvent metabolites used as dose biomarkers. The urinary concentrations of DNA and RNA oxidation products were also measured as biomarkers of oxidative damage. The simultaneous exposure to noise was also evaluated. DPOAEs and pure tone audiometry (PTA) were used as outcome variables, and were correlated to the exposure variables using mixed effect linear regression models.

Study sample: Seventeen industrial painters exposed to a solvent mixture in a naval industry. A sample size of 15 was estimated from previous studies as sufficient for discriminating small hearing level and DPOAE level differences (5 dB and 2 dB, respectively) at a 95% confidence level.

Results: Statistically significant associations were found between the DPOAE level and the urinary dose biomarkers and the oxidative damage biomarkers. DPOAE level and the logarithm of the metabolite concentration showed a significant negative correlation.

Conclusions: DPOAE are sensitive biomarkers of exposure to ototoxic substances and can be effectively used for the early detection of hearing dysfunction.

Keywords:

• Organic solvents
• metabolites
• otoacoustic emissions
• noise

Acknowledgments

The authors are grateful to the local sanitary authority (ASL Marche) for having permitted this study, and to the exposed workers who volunteered in this research.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Grant [BRiC ID17 PAR 2016 – 2018] from the Italian National Institute for Insurance against Accidents at Work.