The National Institute for Occupational Safety and Health released a study last month in its Morbidity and Mortality Weekly Report on hearing impairment among noise-exposed workers in the United States from 2003 to 2012.
This study found a prevalence of 13 percent hearing loss (mild to complete) among 1.4 million audiograms studied. This study confirms and quantifies the prevalence of hearing loss among employees of nine major industry sectors.
The mining, construction, and manufacturing industries had the highest prevalence of workers with any hearing impairment or moderate to severe hearing impairment. Occupational hearing loss, primarily caused by high noise exposure, is the most common U.S. work-related illness.
NIOSH estimates that 22 million U.S. workers are exposed to hazardous occupational noise.
The NIOSH Occupational Hearing Loss Surveillance Project collects de-identified audiograms for U.S. workers who were tested to comply with regulatory requirements because of high occupational noise exposure, defined as ≥85 decibels on the A-scale (dBA).
Audiometric service providers and others that perform worker testing agreed to share these data with NIOSH. A cross-sectional retrospective cohort analysis was conducted using the last audiogram completed for each worker during 2003–2012. Audiograms missing necessary fields or with other quality issues, having hearing threshold values that suggested testing errors, or displaying attributes unlikely to be primarily caused by occupational exposures, were excluded. Industries were classified using the 2007 North American Industry Classification System.
Approximately 78% of the healthy years lost were attributable to mild or moderate hearing impairment. Preventing any occupational hearing loss is the best way to reduce worker hearing impairment over a lifetime because even mild-to-moderate impairment during working years can culminate in more healthy years lost during retirement.
Prevention also has short-term benefits; persons with even mild hearing loss experience reduced audibility (loudness), reduced dynamic range of hearing (the difference between the softest and loudest perceptible sounds), and increased listening fatigue.