Audiometric findings of printing press workers exposed to noise and organic solvents

Abstract

Objective

To determine if exposure to organic solvents and noise is associated with audiometric results among workers from a printing press in Mexico City.

Design

Cross-sectional study.

Study sample

One hundred and seventy-six male workers at a printing press in Mexico City exposed to noise and organic solvents, including xylene, and 103 non-exposed male workers as reference group. Hearing thresholds were assessed with pure-tone audiometry.

Results

Poorer hearing thresholds were observed among printing workers than non-exposed controls, particularly among groups with over 5 years of exposure. Hearing thresholds differences were observed in the frequencies above 500 Hz, especially in 4000 Hz in all exposure groups compared to the reference. Adjusted models for age and previous exposure to noise and organic solvents showed worse hearing thresholds as years of seniority increased –β coefficients (95% CI): ≤5 years: 3.06 dB (0.01, 6.10); >5–10 years: 4.51 dB (1.13, 7.89); >10 years: 4.58 dB (1.20, 7.96). Further analyses showed no interaction between noise and organic solvents on hearing thresholds, considering both current and previous occupational exposures.

Conclusion

Exposure to noise levels that were below recommended exposure limits and organic solvents were associated with poorer hearing thresholds than those observed among non-exposed study participants. This suggests that workers exposed to solvents should be included in hearing conservation programmes, even when noise exposures are below 85 dB. If only noise levels were taken into consideration in the risk assessment of this worker population, the risk of hearing effects could have been overlooked.

Keywords:

• Hearing loss
• occupational exposure
• organic chemicals
• environment and public health
• occupational noise
• xylene

Acknowledgments

The authors thank Dr. Ignacio García Flores, from the printing press medical staff, for his support during our visits to the printing facility.

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

This work was supported by Mexico’s Consejo Nacional de Ciencia y Tecnología under Grant [S0008-FONSEC-02SSA/IMSS/ISSSTE-233661].