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CDC Issues Report on Hearing Impairment among Noise-Exposed Workers in the United States, 2003–2012

Release Date: April 29, 2016

Occupational hearing loss, which is mainly caused by exposure to high noise levels, is the most common occupational illness in the United States (U.S.). Approximately 22 million U.S. workers are exposed to hazardous noise in the workplace.

In a new report published in the April 22, 2016 issue of Morbidity and Mortality Weekly Report (MMWR), the Centers for Disease Control and Prevention (CDC) compared the prevalence (a statistic describing the number of existing cases) of hearing impairment within nine U.S. industry sectors using 1,413,789 noise-exposed worker audiograms completed during the years 2003 to 2012. The data came from CDC’s National Institute for Occupational Safety and Health (NIOSH) Occupational Hearing Loss Surveillance Project. This is the first known study to quantify the healthy years lost due to hearing impairment for noise-exposed U.S. workers and to estimate the prevalence at varying levels of hearing impairment by industry sector.

The NIOSH Occupational Hearing Loss Surveillance Project collects audiograms (without identity) for U.S. workers who were exposed to noise greater than or equal to 85 decibels on the A-scale (dBA) and who were tested, primarily to comply with hearing conservation-related regulations. Audiometric service providers and others that perform worker testing agreed to share the data with NIOSH. CDC estimated the prevalence at six hearing impairment levels measured in the better ear, and the impact on quality of life expressed as annual disability-adjusted life years (DALYs), based on the information and methodology utilized by the World Health Organization’s in its 2013 Global Burden of Disease Study.

Some of the significant findings of the study include:

The CDC notes several limitations regarding the study, such as those relating to the sample selection and the methods used for estimation. In addition, not all noise-exposed workers are tested in the U. S., especially in industries with high proportions of mobile or temporary workers, such as the construction and agriculture sectors. In the absence of other medical records in addition to the audiograms, hearing impairment caused by occupational exposures can only be inferred.

Despite the limitations, the study highlights the high prevalence of hearing loss within the noise-exposed working population and the need for continued prevention efforts, especially in the mining, construction, and manufacturing sectors. 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, early detection, and intervention to preclude additional hearing loss are essential to reducing worker disability caused by hearing impairment. In addition to prevention efforts, early detection of hearing loss by consistent annual audiometric testing and intervention to preclude further loss (e.g., refitting hearing protection, training) are critical.

The full report, “Hearing Impairment Among Noise-Exposed Workers — United States, 2003–2012,” written by NIOSH researchers E. A. Masterson, P. T. Bushnell, C.L. Themann, and T. C. Morata, can be accessed at It contains additional discussion and tables.

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COPYRIGHT ©2016, ISO Services, Inc.