Methods for evaluating temporal trends in noise exposure

Abstract

Objective: Hearing conservation programs have been mandatory in many US industries since 1983. Since then, three program elements (audiometric testing, hearing protection, and training) have been the focus of much research. By comparison, little has been done on noise exposure evaluation. Design: Temporal trends in time weighted average (TWA) exposures and the fraction of measurements exceeding 85 dBA were evaluated by facility, by exposure group within facility, and by individual worker within facility. Study sample: A large dataset (> 10 000 measurements over 20 years) from eight facilities operated by a multinational aluminum manufacturing company was studied. Results: Overall, exposures declined across locations over the study period. Several facilities demonstrated substantial reductions in exposure, and the results of mean noise levels and exceedance fractions generally showed good agreement. The results of analyses at the individual level diverged with analyses by facility and exposure group within facility, suggesting that individual-level analyses, while challenging, may provide important information not available from coarser levels of analysis. Conclusions: Validated metrics are needed to allow for assessment of temporal trends in noise exposure. Such metrics will improve our ability to characterize, in a standardized manner, efforts to reduce noise-induced hearing loss.

Key Words::

• Noise
• hearing conservation
• demographics/epidemiology
• psychoacoustics/hearing science

Note

Data sharing

As an alternative to providing a de-identified data set to the public domain, we allow access for the purpose of re-analyses or appropriate “follow-on” analyses by any qualified investigator willing to sign a contractual covenant with the host Institution limiting use of data to a specific agreed upon purpose and observing the same restrictions as are included in our contract with Alcoa, such as 60-day manuscript review for compliance purposes.

Acknowledgements

This research was funded by a grant from the National Institute for Occupational Safety and Health, R01OH01013202, and by Alcoa Inc. The authors are grateful to Alcoa Inc. for the company's cooperation with this study.

Declaration of interests: Galusha and Rabinowitz receive a portion of their compensation at Yale and Stanford through a long-standing contractual agreement with Alcoa, Inc. Dixon-Ernst is employed by Alcoa, Inc.