Estimation of all-cause noise exposure for U.S. adults from national survey data

Noise Exposure History and Age-Related Changes to Hearing

Importance

Noise exposure is a major modifiable risk factor for hearing loss, yet it is not known whether it affects the rate of hearing decline in aging.

Objective

To determine the association of noise exposure history with the rate of pure-tone threshold change per year.

Design, Setting, and Participants

This longitudinal cohort study was conducted in the ongoing community-based Medical University of South Carolina Longitudinal Cohort Study of Age-Related Hearing Loss (1988 to present with the sample based in Charleston, South Carolina, and surrounding area). Following a comprehensive baseline examination, participants attended annual examinations, during which audiometric data were collected. Participants with audiometric data from at least 2 examinations and noise exposure history data were included in the study. Data were analyzed between September 2023 and July 2024.

Exposure

Noise exposure history, determined by a self-reported questionnaire and history of military service, was categorized as no/little, some, or high exposure.

Main Outcomes and Measures

Outcome measures were individual audiometric thresholds (0.25 kHz to 8.0 kHz) and pure-tone average (PTA) of thresholds at frequencies 0.5 kHz, 1.0 kHz, 2.0 kHz, and 4.0 kHz, averaged bilaterally. Linear mixed regression models were used to estimate the association of age (per every 1 additional year) with the rate of threshold change at each frequency and PTA, for each noise exposure category. The association of noise exposure with the rate of annual threshold change was determined by an interaction term of age (longitudinal time variable) and noise exposure in regression models.

Results

Of 1347 participants, the mean (SD) baseline age was 63 (14) years, and 772 (57%) were female. The mean (SD) follow-up time was 5.1 (5.7) years. Compared to the no/little noise exposure group, groups with some and high noise exposure had significantly higher baseline thresholds from 2.0 kHz to 8.0 kHz and PTA, and 1.0 kHz to 8.0 kHz and PTA, respectively. Those with high noise exposure (vs no/little) showed higher rates of threshold change per year at 1.0 kHz and 2.0 kHz. Participants with some and high noise exposure showed lower rates of change per year at 3.0 kHz to 8.0 kHz and 4.0 kHz to 8.0 kHz, respectively, where hearing loss had already occurred. The rate of PTA change per year did not differ across noise exposure groups.

Conclusions and Relevance

In this cohort study, noise exposure was associated with poorer baseline hearing and higher rates of annual decline at some midfrequencies. Noise exposure can have immediate and potentially long-term negative impacts on hearing.

Demographic and Audiological Characteristics of Candidates for Over-the-Counter Hearing Aids in the United States

OBJECTIVES

This report presents descriptive data on the demographic and audiological characteristics of US adults with perceived mild-to-moderate hearing loss, the primary candidates for over-the-counter (OTC) hearing aids.

DESIGN

The analyses are descriptive and present population-weighted responses for various self-reported demographic and audiological variables for adults with mild or moderate perceived hearing trouble. Results of pure-tone audiometry and immittance measures are also presented. Nationally representative datasets from the National Health and Nutrition Examination Surveys (NHANES) for 2011 to 2012, 2015 to 2016, and 2017 to 2020, the three most recent NHANES datasets with audiological information, were used.

RESULTS

The NHANES datasets indicated that there are 49.5 million adults in the United States with perceived mild-to-moderate hearing trouble. Results indicated that OTC hearing-aid candidates are most frequently 50 to 69 years of age, married, and identify as non-Hispanic White race/ethnicity. Most of these individuals graduated from high school, had several risk factors for hearing loss, had not had a hearing test in the past 5 years, and had never used hearing aids or assistive listening devices previously. The typical audiometric profile was a bilaterally symmetrical sloping hearing loss with slight to mild hearing loss above 2000 Hz. Group data showed normal immittance measures and absence of otoscopic abnormalities except for the presence of excessive (not impacted) cerumen in about 13% of the OTC hearing-aid candidates.

CONCLUSIONS

Tens of millions of US adults have perceived mild-to-moderate hearing trouble but have not pursued assistance, either through obtaining a hearing test or acquiring prescription hearing aids.

The prevalence of bilateral hearing loss in the United States in 2019: a small area estimation modelling approach for obtaining national, state, and county level estimates by demographic subgroup

Background

The goal of this study was to re-estimate rates of bilateral hearing loss Nationally, and create new estimates of hearing loss prevalence at the U.S. State and County levels.

Methods

We developed small area estimation models of mild, and moderate or worse bilateral hearing loss in the U.S. using data from the National Health and Nutrition Examination Survey (2001-2012, 2015-2018), the American Community Survey (2019), Census County Business Patterns (2019); Social Security Administration Data (2019); Medicare Fee-for-Service and Advantage claims data (2019); the Area Health Resources File (2019), and other sources. We defined hearing loss as mild (>25 dB through 40 dB), moderate or worse (>40 dB), or any (>25 dB) in the better hearing ear based on a 4-frequency pure-tone-average threshold, and created estimates by age group (0-4, 5-17, 18-34, 35-64, 65-74, 75+), gender, race and ethnicity, state, and county.

Findings

We estimated that 37.9 million (95% Uncertainty Interval [U.I.] 36.6-39.1) Americans experienced any bilateral hearing loss; 24.9 million (95% U.I. 23.6-26.0) with mild and 13.0 million (95% U.I. 12.1-13.9) with moderate or worse. The prevalence rate of any hearing loss was 11.6% (95% U.I. 11.2%-12.0%). Hearing loss increased with age. Men were more likely to have hearing loss than women after age 35, and non-Hispanic Whites had higher rates of hearing loss than other races and ethnicities. Higher hearing loss prevalence was associated with smaller population size. West Virginia, Alaska, Wyoming, Oklahoma, and Arkansas had the highest standardised rate of bilateral hearing loss, and Washington D.C., New Jersey, New York, Maryland, and Connecticut had the lowest.

Interpretation

Bilateral Hearing loss varies by State and County, with variation associated with population age, race and ethnicity, and population size. Geographic estimates can be used to raise local awareness of hearing loss as a problem, to prioritize areas for hearing loss prevention, identification, and treatment, and to guide future research on the hearing loss risk factors that contribute to these differences.

Funding

CDC's National Center for Chronic Disease Prevention and Health Promotion, Division of Population Health.

Easy as 1-2-3: Development and Evaluation of a Simple yet Valid Audiogram-Classification System

Almost since the inception of the modern-day electroacoustic audiometer a century ago the results of pure-tone audiometry have been characterized by an audiogram. For almost as many years, clinicians and researchers have sought ways to distill the volume and complexity of information on the audiogram. Commonly used approaches have made use of pure-tone averages (PTAs) for various frequency ranges with the PTA for 500, 1000, 2000 and 4000 Hz (PTA4) being the most widely used for the categorization of hearing loss severity. Here, a three-digit triad is proposed as a single-number summary of not only the severity, but also the configuration and bilateral symmetry of the hearing loss. Each digit in the triad ranges from 0 to 9, increasing as the level of the pure-tone hearing threshold level (HTL) increases from a range of optimal hearing (< 10 dB Hearing Level; HL) to complete hearing loss (≥ 90 dB HL). Each digit also represents a different frequency region of the audiogram proceeding from left to right as: (Low, L) PTA for 500, 1000, and 2000 Hz; (Center, C) PTA for 3000, 4000 and 6000 Hz; and (High, H) HTL at 8000 Hz. This LCH Triad audiogram-classification system is evaluated using a large United States (U.S.) national dataset (N = 8,795) from adults 20 to 80 + years of age and two large clinical datasets totaling 8,254 adults covering a similar age range. Its ability to capture variations in hearing function was found to be superior to that of the widely used PTA4.

Hearing thresholds for "otologically normal" adults from the National Health and Nutrition Examination Surveys 2011-12 and 2015-16

Hearing threshold levels (HTLs) get worse with advancing age in adults. Publications of nationally representative data from U.S. adults have been confined to HTLs from unscreened individuals. ISO 7029:2017 provides equations for the hearing loss of adults of various ages. Equations were generated from a synthesis of international studies of HTLs for "otologically normal" or screened adults. No nationally representative data for screened U.S. adults were included in the ISO synthesis. This study investigated three different levels of screening rigor, referred to here as Screened, Screened+, and Screened++. Median HTLs are provided for Screened (N = 1545) and Screened++ (N = 795) groups from the National Health and Nutrition Examination Surveys for 2011-12 and 2015-16, the two most recent surveys of adults from 20 to 69 years of age with audiograms. Median HTLs from the Screened and Screened++ groups differed slightly between the sexes, were not affected by race/ethnicity, and increased substantially with age. For young adults, there were no differences in HTLs between screened (any level) and unscreened adults, but such differences in HTLs increased with advancing age, especially at higher frequencies. The default power-function model from ISO 7029:2017 did not provide a good description of the median age-associated HTLs from screened U.S. adults.

Noise-induced hearing disorders: Clinical and investigational tools

A series of articles discussing advanced diagnostics that can be used to assess noise injury and associated noise-induced hearing disorders (NIHD) was developed under the umbrella of the United States Department of Defense Hearing Center of Excellence Pharmaceutical Interventions for Hearing Loss working group. The overarching goals of the current series were to provide insight into (1) well-established and more recently developed metrics that are sensitive for detection of cochlear pathology or diagnosis of NIHD, and (2) the tools that are available for characterizing individual noise hazard as personal exposure will vary based on distance to the sound source and placement of hearing protection devices. In addition to discussing the utility of advanced diagnostics in patient care settings, the current articles discuss the selection of outcomes and end points that can be considered for use in clinical trials investigating hearing loss prevention and hearing rehabilitation.