Costs and effectiveness of hearing conservation programs at 14 US metal manufacturing facilities.
Stephanie K Sayler, Peter M Rabinowitz, Linda F Cantley and 2 others
PMID 29216778WHAT IT FOUND
Total hearing conservation spending did not predict hearing loss rates.
However, sites that paid for fit-testing had lower rates of standard threshold shifts. Spending on certification and hearing protection devices was associated with higher reported hearing loss, likely because these costs rise when problems are detected.
Key findings
01Total cost per person for hearing conservation programs was not a significant predictor of any hearing health outcome.
02Expenditures on fit-testing were a significant predictor of lower rates of non-age-corrected standard threshold shifts, even after statistical corrections.
03Facilities with higher spending on hearing protection devices and technician certification had higher rates of hearing impairment and standard threshold shifts.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study included only 14 facilities from a single company in one industry, limiting generalizability. The sample size was too small to control for important variables like employee age or baseline noise levels in the statistical models. Costs for noise controls and insurance premiums were not included in the analysis. The association between higher spending on hearing protection and worse hearing outcomes may be due to reverse causality (spending increases after problems arise), which the study cannot definitively rule out.
Declared interests
The study was supported by the National Institute for Occupational Safety and Health (NIOSH) and involved a research and data sharing relationship with the company whose facilities were studied.
The easy way to misread this
Do not conclude that buying more hearing protection devices causes hearing loss. The association between high equipment spending and poor hearing outcomes likely reflects facilities reacting to existing problems by purchasing more gear, not the gear itself being harmful.