Association between occupational noise exposure level and pure-tone audiometry abnormalities among Metropolitan Manila Development Authority employees: A cross-sectional study

Abstract

Traffic enforcers are exposed to various occupational health and safety hazards, including noise pollution, which may lead to occupational hearing loss. This cross-sectional study aimed to estimate the prevalence of hearing loss and to assess the relationship between occupational noise exposure level (ONEL) and abnormalities in air conduction thresholds among Metropolitan Manila Development Authority (MMDA) employees along Epifanio delos Santos Avenue, Philippines. Eight-hour ONELs were measured among 108 participants working with greater than 5 years of service. Participants had hearing evaluations using pure tone audiometry (PTA) to calculate the prevalence of hearing loss. Generalized linear models with a Poisson distribution were fitted to estimate the association between ONEL and audiologic abnormalities, controlling for confounding factors. Approximately 16% of employees had hearing loss. The prevalence of hearing loss was higher with ONEL exposures greater than 85 A-weighted decibels (dBA), with traffic enforcers exposed to higher ONELs than office workers. ONELs greater than 85 dBA were related to audiologic abnormalities at different frequencies in PTA. The prevalence of audiologic abnormalities at 4000 Hz and 6000 Hz was 48% higher (adjusted prevalence ratio [aPR], 1.48; 95% CI, 1.12–1.96) and 25% higher (aPR, 1.25; 95% CI, 1.00–1.55), respectively, among participants with ONELs greater than 85 dBA than with ONELs less than or equal to 85 dBA. Participants exposed to ONELs greater than 85 dBA, more likely traffic enforcers, may have increased risk of audiologic abnormalities. Regular ONEL monitoring is warranted for occupational risk assessment of traffic enforcers. A hearing conservation program may need to be considered for this population. Additional studies are needed to determine trends in hearing deterioration among traffic enforcers.

Keywords:

• Noise pollution
• occupational hearing loss
• occupational hazard
• road traffic noise
• traffic enforcement
• traffic safety

Acknowledgments

We thank the MMDA for allowing us to conduct this study. Special thanks to the following individuals for their assistance in this project: MMDA Chairman Atty. Romando S. Artes, Atty. Victor Maria Nunez, Mr. Jeffrey Torres, Dr. Annabelle R. Ombina, Ms. Marielle M. Santos, and Ms. Kate Ivy T. Guda of the MMDA for their assistance in coordination and logistics; Mr. Melvin Keir D. Lamela and Mr. Francis Arlan Mauricio, who assisted with noise exposure level monitoring; Dr. Ma. Leah Tantoco, Ms. Symonette Patrimonio, Ms. Lianne Reveche, and Ms. Dee Alojado, who performed the audiologic assessment on the MMDA employees; UP Manila, through the UP-PGH Ear Unit, for allowing us to borrow audiologic equipment necessary to carry out the study; Ms. Carolyn Paet, for her participation in the determination of corrective factors for audiologic testing; and Mr. Aaron Pontillas, for his assistance in graphic presentations.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The participants of this study did not give written consent for their individual participant-level data to be shared publicly.

Additional information

Funding

The University of the Philippines National Institutes of Health Faculty Grant 2022 provided the funding for the study [NIH-2022-012].