Mar 5, 2018

Promoting Hearing Health Across the Lifespan

Globally, one in three adults has some level of measurable hearing loss, and 1.1 billion young persons are at risk for hearing loss attributable to noise exposure. Although noisy occupations such as construction, mining, and manufacturing are primary causes of hearing loss in adults, nonoccupational noise also can damage hearing. Loud noises can cause permanent hearing loss through metabolic exhaustion or mechanical destruction of the sensory cells within the cochlea. Some of the sounds of daily life, including those made by lawn mowers, recreational vehicles, power tools, and music, might play a role in the decline in hearing health. Hearing loss as a disability largely depends on a person's communication needs and how hearing loss affects the ability to function in a job. The loss of critical middle and high frequencies can significantly impair communication in hearing-critical jobs (e.g., law enforcement and air traffic control).

Occupational Noise-Induced Hearing Loss
A recent analysis of 2011–2012 National Health and Nutrition Examination Survey (NHANES) data estimates that approximately 14% of U.S. adults aged 20–69 years (27.7 million persons) have hearing loss. After adjustments for age and sex, hearing impairment was nearly twice as prevalent in men as in women; age, sex, ethnicity, and firearm use were all important risk factors for hearing loss (1).

CDC's National Institute for Occupational Safety and Health (NIOSH) estimates that 22 million workers are exposed to hazardous levels of noise in their workplaces (2). The estimated prevalence of hearing loss among noise-exposed workers is 12%–25%, depending on type of industry. Reductions in workplace noise and increased use of hearing protection might have contributed to a decreased prevalence of hearing loss over time in some sectors, including agriculture, forestry, fishing, and hunting and transportation, warehousing, and utilities (3). The risk for incident hearing loss (i.e., the likelihood of observing a new case of hearing loss in a worker's longitudinal audiometric data) decreased by 46% from the periods 1986–1990 to 2006–2010 (3).

For high exposure levels such as firearm or aircraft noise above 140 decibels sound pressure level (dB SPL), engineering and administrative controls might not reduce noise exposures adequately. Such situations require hearing protection devices (HPDs) providing upwards of 30–40 dB of noise reduction when worn properly. Despite the existence of occupational regulations for hearing protection, many workers fail to achieve adequate protection because their earplugs or earmuffs do not fit properly. Hearing protector fit testing provides an opportunity to train workers to properly fit hearing protectors and to encourage effective use. The NIOSH HPD Well-Fit hearing protector fit-test system is a simple, portable solution for testing in quiet office spaces. Other fit-testing systems are commercially available (4).

Nonoccupational Noise-Induced Hearing Loss
Primary sources of nonoccupational hearing loss in the United States include noise exposure from recreational hunting or shooting, use of personal music players, overexposure at concerts and clubs, and certain hobbies (e.g., motorsports and woodworking with power tools). In 2016, CDC began initiatives to raise awareness about the risk for permanent hearing damage attributable to nonoccupational noise exposures, including the development of new communication tools about noise-induced hearing loss. An analysis of 2011–2012 NHANES audiometric data from 3,583 adults aged 20–69 years identified persons with high-frequency audiometric notches suggestive of noise-induced hearing loss (5). Persons with normal hearing can detect sounds equally soft at all frequencies. When hearing is damaged by noise, the hearing test will show a loss of acuity in a narrow range of middle to high frequencies (3–6 kHz) with better hearing at both lower and higher frequencies. Often, the earliest sign is a notched configuration in the audiogram

Read on at:
​​CDC Grand Rounds: Promoting Hearing Health Across the Lifespan
Weekly / March 2, 2018 / 67(8);243–246

William J. Murphy, PhD1; John Eichwald, MA2; Deanna K. Meinke, PhD3; Shelly Chadha, PhD4; John Iskander, MD5