Abstract

Background.

Hearing loss has been associated with cognitive and functional decline in older adults and may be amenable to rehabilitative interventions, but national estimates of hearing loss prevalence and hearing aid use in older adults are unavailable.

Methods.

We analyzed data from the 2005–2006 cycle of the National Health and Nutritional Examination Survey, which is the first cycle to ever incorporate hearing assessment in adults aged 70 years and older. Audiometry was performed in 717 older adults, and data on hearing aid use, noise exposure, medical history, and demographics were obtained from interviews. Analyses incorporated sampling weights to account for the complex sampling design and yield results that are generalizable to the U.S. population.

Results.

The prevalence of hearing loss defined as a speech frequency pure tone average of more than 25 dB in the better ear was 63.1% (95% confidence interval: 57.4–68.8). Age, sex, and race were the factors most strongly associated with hearing loss after multivariate adjustment, with black race being substantially protective against hearing loss (odds ratio 0.32 compared with white participants [95% confidence interval: 0.19–0.53]). Hearing aids were used in 40.0% (95% confidence interval: 35.1–44.8) of adults with moderate hearing loss, but in only 3.4% (95% confidence interval: 0.8–6.0) of those with a mild hearing loss.

Conclusion.

Hearing loss is prevalent in nearly two thirds of adults aged 70 years and older in the U.S. population. Additional research is needed to determine the epidemiological and physiological basis for the protective effect of black race against hearing loss and to determine the role of hearing aids in those with a mild hearing loss.

HEARING loss in older adults is highly prevalent, and recent studies have demonstrated independent associations of hearing loss with incident dementia (1), driving ability (2), and walking difficulty (3). Other studies have shown associations between hearing loss and social isolation (4,5), cognition (6–8), functional decline (5,9), and falls (10). Various hypotheses have been proposed to explain the basis of these observed associations. One possibility is that poor hearing requires greater cognitive resources for auditory decoding leading to less cognitive resource capacity for other tasks (8,11). Another possibility is that poor hearing leads to communication impairments and progressive social isolation that may mediate downstream health and functional consequences (12,13). Finally, a common etiology, such as from progressive mitochondrial dysfunction, could underlie both hearing loss and cognitive decline (14,15). Importantly, none of these proposed pathways are mutually exclusive, and coexistent pathways could potentially lead to the same outcome.

Under the hypothesis that hearing loss directly or indirectly leads to cognitive and physical decline, it is reasonable to hypothesize that hearing aids or other aural rehabilitative devices could mitigate these outcomes. Indeed, one moderate-sized randomized controlled trial of hearing aids demonstrated positive effects of hearing aids on cognition and other functional domains (16). A larger trial has never been carried out to confirm these findings definitively.

Surprisingly, despite the potential impact of hearing loss on aging and the possibility of interventional modalities to treat hearing loss, national estimates of hearing loss prevalence and hearing aid use in older adults are unavailable. Previous studies of hearing loss in older adults have been in nonrepresentative cohorts (17–19), and these studies have resulted in different estimates of hearing loss prevalence even when the same definition of hearing loss was applied across studies (18).

In the current study, we utilize data from the 2005–2006 cycle of the National Health and Nutritional Examination Survey (NHANES) to study the epidemiology of hearing loss and derive prevalence estimates that are generalizable to adults aged 70 years and older in the U.S. population.

METHODS

Study Cohort

The NHANES is an ongoing program of studies designed to assess the health, functional, and nutritional status of the civilian noninstitutionalized U.S. population. Each sequential cross-sectional study uses a complex sampling design to survey a sample of the population, with selective oversampling of low-income individuals, racial minorities, and older adults (20). Sampling weights allow for analyses that account for the complex sampling survey and yield results that are generalizable to the U.S. population.

We used data from the 2005–2006 cycle when hearing loss was assessed in adults aged 70 years and older. Overall, 827 older adults participated in both the interview and medical examination, and of these, 110 did not undergo or had incomplete audiometric testing in the speech frequencies (0.5–4 kHz). Individuals with missing audiometric data were more likely to be older, women, and have less education than the 717 individuals who completed audiometric testing.

Audiometric Assessment

Audiometry was performed by a trained examiner according to established NHANES protocols (21). Briefly, air conduction hearing thresholds were conducted on both ears in a dedicated sound-isolating room in the mobile examination center. Testing was conducted according to a modified Hughson Westlake procedure using the automated testing mode of the audiometer (Interacoustics AD226, Interacoustics, Eden Prarie, MN) and/or manually per the testing protocol. Quality assurance and quality control were established through daily calibration of equipment and monitoring of ambient noise levels using a sound level meter. The audiometric test room met or exceeded ANSI S3.1-1991 guidelines for maximum permissible ambient noise levels. Air conduction stimuli were presented primarily through supraaural earphones (TDH 39P, Telephonics Corp, Farmingdale, NY). Insert earphones (ER3A, Etymotic Research, Inc., Elk Grove Village, IL) were reserved for cases of collapsing ear canals or for a retesting protocol in cases of asymmetric hearing loss (masking was not performed). As an additional quality measure, thresholds were measured twice at 1 kHz in both ears, and audiometry was repeated if there was more than 10 dB discrepancy between the threshold measurements.

We utilized hearing thresholds from 0.5 to 8 kHz, using the first threshold tested at 1 kHz and incorporating manual retest thresholds as needed. Pure tone averages (PTA) were calculated for standard PTA (0.5, 1, and 2 kHz), speech frequency PTA (0.5, 1, 2, and 4 kHz), and high-frequency PTA (3, 4, 6, and 8 kHz). Categories of hearing loss severity were based on American Speech-Language Hearing Association guidelines (22), but several of the categories were collapsed to simplify analyses (normal hearing ≤ 25 dB, mild loss >25 dB and ≤ 40 dB, moderate loss >40 dB and ≤70 dB, severe loss >70 dB). All hearing thresholds in this manuscript are reported as dB HL (American National Standards Institute, 2004).

Other Study Variables

Data on demographic variables, history of noise exposure, and medical history were obtained from interviews. Race/ethnicity was grouped as Mexican-American or other Hispanic, non-Hispanic white, non-Hispanic black, or other race. Education and household income were collapsed into a 3 and 4 level variable, respectively. Noise exposure history incorporated assessment (yes/no) of firearm use (use of firearms for target shooting, hunting, or other purposes), occupational noise (exposure to loud noise for ≥5 hours a week), and leisure noise (exposure to steady loud noise or music for ≥5 hours a week). Hearing aid use was based on whether an individual had used a hearing aid for ≥5 hours a week in the past 12 months. Variables related to medical history included diabetes (based on self-reported diagnosis and/or current use of insulin or other diabetic medications), smoking (current/former/never), hypertension (told by physician on two or more visits about hypertension diagnosis), and stroke (self-reported history).

Statistical Methodology

We accounted for the complex sampling design in all analyses by using sample weights according to National Center for Health Statistics guidelines (23). The population prevalence of hearing loss using different definitions of hearing loss was calculated with 95% confidence intervals (95% CI). Regression analyses were used to determine the association between hearing loss or hearing aid use with studied covariates. When considering hearing loss or hearing aid use as a dichotomous variable, logistic regression models were utilized to calculate odds ratios. When examining hearing loss as a continuous variable, linear regression models were used to obtain β coefficients. The β coefficient is interpreted as the average change in hearing threshold (in dB, positive values indicate greater hearing loss, negative values indicate less hearing loss) per unit change in the studied covariate. Per National Center for Health Statistics guidelines, age standardization was performed utilizing the 2000 Census population, and the Taylor Series Linearization method was used for variance estimation (23). Missing nonaudiometric data comprised less than 2% of the data in any analysis, and these individuals were excluded. All analyses were conducted using STATA 11.0 (StataCorp, College Station, TX), and p < .05 were considered statistically significant.

RESULTS

Variability in Hearing Loss Prevalence by Case Definition

The prevalence of hearing loss in older adults varies substantially depending on the tonal frequencies utilized to calculate the PTA, the audiometric threshold defining hearing loss, and whether hearing loss is being considered in the better or worse hearing ear (Table 1). Hearing loss prevalence rates ranged from 16.5% (95% CI: 13.2–19.9) when hearing loss was defined using a standard PTA (0.5, 1, and 2 kHz) with a 40 dB threshold in the better hearing ear to 99.7% (95% CI: 99.1–100) when using a high-frequency PTA (3, 4, 6, and 8 kHz) with a 15 dB threshold in the worse ear. Most prior reports of hearing loss prevalence in adults have used a 25 dB threshold, standard or speech frequency PTA, and either the worse or better ear. However, even with this more limited definition, hearing loss prevalence rates still range from 44.8% (standard PTA in the better ear) to 75.1% (speech frequency PTA in the worse ear).

Table 1.

Prevalence of Hearing Loss in Adults Aged 70 Years and Older According to Varying Definitions of Hearing Loss, National Health and Nutritional Examination Survey 2005–2006

 Prevalence (95% CI)*
 
 15 dB Threshold 25 dB Threshold 40 dB Threshold 
Standard PTA (0.5, 1, 2 kHz)    
    Unilateral† 13.2 (10.4–15.9) 16.1(11.9–20.3) 11.7 (9.1–14.4) 
    Bilateral/better ear 75.6 (73.0–78.2) 44.8 (40.4–49.2) 16.5 (13.2–19.9) 
    Worse ear 88.6 (85.1–92.2) 60.7 (54.3–67.1) 28.2 (23.9–32.4) 
Speech frequency PTA (0.5, 1, 2, 4 kHz)    
    Unilateral† 7.0 (4.0–10.0) 12.1 (9.0–15.3) 13.5 (10.4–16.5) 
    Bilateral/better ear 87.9 (84.2–91.7) 63.1 (57.4–68.8) 26.5 (22.9 -30.2) 
    Worse ear 94.9 (93.0–96.7) 75.1 (69.7–80.5) 39.9 (36.5–43.3) 
High-frequency PTA (3, 4, 6, 8 kHz)    
    Unilateral† 2.0 (0.9–3.0) 4.4 (2.4–6.4) 10.2 (5.9–14.5) 
    Bilateral/better ear 97.8 (96.6–98.9) 90.9 (88.2–93.6) 74.1 (67.2–80.9) 
    Worse ear 99.7 (99.1–100) 95.2 (92.8–97.6) 84.0 (79.6–88.5) 
 Prevalence (95% CI)*
 
 15 dB Threshold 25 dB Threshold 40 dB Threshold 
Standard PTA (0.5, 1, 2 kHz)    
    Unilateral† 13.2 (10.4–15.9) 16.1(11.9–20.3) 11.7 (9.1–14.4) 
    Bilateral/better ear 75.6 (73.0–78.2) 44.8 (40.4–49.2) 16.5 (13.2–19.9) 
    Worse ear 88.6 (85.1–92.2) 60.7 (54.3–67.1) 28.2 (23.9–32.4) 
Speech frequency PTA (0.5, 1, 2, 4 kHz)    
    Unilateral† 7.0 (4.0–10.0) 12.1 (9.0–15.3) 13.5 (10.4–16.5) 
    Bilateral/better ear 87.9 (84.2–91.7) 63.1 (57.4–68.8) 26.5 (22.9 -30.2) 
    Worse ear 94.9 (93.0–96.7) 75.1 (69.7–80.5) 39.9 (36.5–43.3) 
High-frequency PTA (3, 4, 6, 8 kHz)    
    Unilateral† 2.0 (0.9–3.0) 4.4 (2.4–6.4) 10.2 (5.9–14.5) 
    Bilateral/better ear 97.8 (96.6–98.9) 90.9 (88.2–93.6) 74.1 (67.2–80.9) 
    Worse ear 99.7 (99.1–100) 95.2 (92.8–97.6) 84.0 (79.6–88.5) 

Notes: CI = confidence interval; PTA = pure tone average.

*

Prevalence values represent the weighted percentage of older adults with pure tone averages (standard, speech frequency, or high frequency) above the designated threshold.

Definitions of hearing loss based on the “better hearing ear” or “bilateral loss” are identical. Hearing loss defined by the better hearing ear/bilateral loss is mutually exclusive from unilateral loss. Using the worse hearing ear to define hearing loss incorporates cases defined by the better hearing ear/bilateral loss and cases defined by unilateral loss.

Herein, we adopt the definition of hearing loss adjudicated by the World Health Organization (speech frequency PTA in the better ear with a 25 dB threshold) (24). Using this definition, the prevalence of hearing loss in adults aged 70 years and older was 63.1% (95% CI: 57.4–68.8).

Prevalence and Correlates of Hearing Loss

In multivariate models adjusting for all confounders (Table 2), the odds of hearing loss were significantly associated with increasing age (p < .001 for all age categories) and male sex (odds ratio [OR] 1.67 [95% CI: 1.09–2.55]), whereas black race was strongly protective against hearing loss (OR = 0.32 [95% CI: 0.19–0.53]). Across 5-year age groupings, acceleration in hearing loss prevalence was greatest between 70–74 years and 75–79 years (45.6%–67.6%), with tapering increases in prevalence thereafter (78.2% in 80–84 years and 80.6% in >85 years). The prevalence of hearing loss in black participants (43.3%, [95% CI: 31.1–55.5]) was significantly lower than in white participants (64.4% [95% CI: 58.1–70.8]) (p = .003). We found no significant association between history of noise exposure or medical conditions with hearing loss.

Table 2.

Prevalence and Correlates of Hearing Loss in Adults Aged 70 Years and Older, National Health and Nutritional Examination Survey 2005–2006

 Hearing Loss >25 db in Speech Frequency PTA†
 
Multivariate Analyses With Hearing Loss as a Continuous Variable†,‡
 
 Prevalence§(95% CI) Univariate OR‖(95% CI) Multivariate OR¶ (95% CI) Standard PTA (0.5–2 kHz),β (95% CI)# Speech Frequency PTA(0.5–4 kHz), β (95% CI)# High-Frequency PTA(3–8 kHz), β (95% CI)# 
Demographic       
    Age (y)       
        70–74 45.6 (39.3–51.8) Reference Reference Reference Reference Reference 
        75–79 67.6 (58.8–76.3) 2.49*** (1.79–-3.46) 2.65*** (1.86–3.78) 6.84*** (4.23–9.45) 7.37*** (5.13–9.61) 8.61*** (4.95–12.3) 
        80–84 78.2 (73.0–83.4) 4.28*** (3.36–5.45) 4.30*** (3.06–6.03) 9.84*** (7.48–12.2) 10.8*** (8.26–13.3) 13.2*** (9.68–16.6) 
        ≥85 80.6 (72.6–88.7) 4.97*** (2.69–9.20) 5.44*** (2.74–10.8) 16.6*** (12.5–20.7) 16.1*** (12.7–19.5) 15.4*** (11.8–19.1) 
    Sex       
        Female 58.2 (50.7–65.6) Reference Reference Reference Reference Reference 
        Male 69.8 (63.6–75.9) 1.66** (1.20–2.30) 1.67* (1.09–2.55) — 4.23* (0.90–7.56) 11.5*** (7.50–15.5) 
    Race       
        Non-Hispanic white 64.4 (58.1–70.8) Reference Reference Reference Reference Reference 
        Non-Hispanic black 43.3 (31.1–55.5) 0.42** (0.25–0.71) 0.32*** (0.19–0.53) -3.49* (−6.60 to −0.38) −5.84*** (−8.58 to −3.10) −11.1*** (−13.9 to −8.23) 
        Mexican or other Hispanic 65.1 (50.0–80.2) 1.03 (0.51–2.07) — — — — 
        Other 74.6 (46.1–100) 1.62 (0.32–8.14) — — — — 
       Education       
        < 12th grade 70.1 (62.0–78.2) Reference Reference Reference Reference Reference 
        High school graduate 62.3 (52.5–72.1) 0.70 (0.44–1.13) — — — −3.07* (−6.00 to −0.14) 
        Some college or more 58.5 (52.3–64.6) 0.60* (0.38–0.94) — — −2.22* (−4.39 to −0.06) −5.06** (−8.39 to −1.74) 
    Household income       
        <$20 K/y 69.2 (62.5–76.0) Reference Reference Reference Reference Reference 
        $20K to <$45K 64.8 (57.7–71.9) 0.82 (0.57–1.17) — — — — 
        ≥$45K 57.1 (48.3–66.0) 0.59* (0.39–0.91) — −2.92* (−5.48 to −0.36) −2.43* (−4.62 to −0.23) — 
        Refused/don’t know 47.5 (23.6–71.3) 0.40 (0.15–1.11) 0.38* (0.15–0.98) — — — 
Noise exposure       
    Firearm use       
        Yes 68.2 (60.9–75.5) 1.44* (1.01–2.05) — — — 2.65* (0.12–5.19) 
        No 59.9 (53.1–66.7) Reference Reference Reference Reference Reference 
    Occupational exposure       
        Yes 72.2 (65.0–79.4) 1.87* (1.07–3.28) — — — — 
        No 58.2 (49.4–66.9) Reference Reference Reference Reference Reference 
    Leisure exposure       
        Yes 72.6 (66.6–78.6) 1.65** (1.19–2.29) — — — 3.87* (0.81–6.93) 
        No 61.6 (55.6–67.7) Reference Reference Reference Reference Reference 
Medical history       
    Diabetes       
        Yes 64.9 (56.6–73.1) 1.10 (0.71–1.70) — — — — 
        No 62.7 (56.1–69.3) Reference Reference Reference Reference Reference 
    Smoking       
        Never 62.6 (54.2–71.1) Reference Reference Reference Reference Reference 
        Former 64.4 (58.0–70.8) 1.08 (0.69–1.68) — — — — 
        Current 58.2 (43.0–73.3) 0.83 (0.47–1.45) — — — — 
    Hypertension       
        Yes 60.4 (54.6–66.2) 0.79 (0.57–1.11) — — — — 
        No 65.7 (57.9–73.6) Reference Reference Reference Reference Reference 
    Stroke       
        Yes 69.2 (53.2–85.2) 1.34 (0.69–2.59) — — — — 
        No 62.7 (57.4–67.9) Reference Reference Reference Reference Reference 
 Hearing Loss >25 db in Speech Frequency PTA†
 
Multivariate Analyses With Hearing Loss as a Continuous Variable†,‡
 
 Prevalence§(95% CI) Univariate OR‖(95% CI) Multivariate OR¶ (95% CI) Standard PTA (0.5–2 kHz),β (95% CI)# Speech Frequency PTA(0.5–4 kHz), β (95% CI)# High-Frequency PTA(3–8 kHz), β (95% CI)# 
Demographic       
    Age (y)       
        70–74 45.6 (39.3–51.8) Reference Reference Reference Reference Reference 
        75–79 67.6 (58.8–76.3) 2.49*** (1.79–-3.46) 2.65*** (1.86–3.78) 6.84*** (4.23–9.45) 7.37*** (5.13–9.61) 8.61*** (4.95–12.3) 
        80–84 78.2 (73.0–83.4) 4.28*** (3.36–5.45) 4.30*** (3.06–6.03) 9.84*** (7.48–12.2) 10.8*** (8.26–13.3) 13.2*** (9.68–16.6) 
        ≥85 80.6 (72.6–88.7) 4.97*** (2.69–9.20) 5.44*** (2.74–10.8) 16.6*** (12.5–20.7) 16.1*** (12.7–19.5) 15.4*** (11.8–19.1) 
    Sex       
        Female 58.2 (50.7–65.6) Reference Reference Reference Reference Reference 
        Male 69.8 (63.6–75.9) 1.66** (1.20–2.30) 1.67* (1.09–2.55) — 4.23* (0.90–7.56) 11.5*** (7.50–15.5) 
    Race       
        Non-Hispanic white 64.4 (58.1–70.8) Reference Reference Reference Reference Reference 
        Non-Hispanic black 43.3 (31.1–55.5) 0.42** (0.25–0.71) 0.32*** (0.19–0.53) -3.49* (−6.60 to −0.38) −5.84*** (−8.58 to −3.10) −11.1*** (−13.9 to −8.23) 
        Mexican or other Hispanic 65.1 (50.0–80.2) 1.03 (0.51–2.07) — — — — 
        Other 74.6 (46.1–100) 1.62 (0.32–8.14) — — — — 
       Education       
        < 12th grade 70.1 (62.0–78.2) Reference Reference Reference Reference Reference 
        High school graduate 62.3 (52.5–72.1) 0.70 (0.44–1.13) — — — −3.07* (−6.00 to −0.14) 
        Some college or more 58.5 (52.3–64.6) 0.60* (0.38–0.94) — — −2.22* (−4.39 to −0.06) −5.06** (−8.39 to −1.74) 
    Household income       
        <$20 K/y 69.2 (62.5–76.0) Reference Reference Reference Reference Reference 
        $20K to <$45K 64.8 (57.7–71.9) 0.82 (0.57–1.17) — — — — 
        ≥$45K 57.1 (48.3–66.0) 0.59* (0.39–0.91) — −2.92* (−5.48 to −0.36) −2.43* (−4.62 to −0.23) — 
        Refused/don’t know 47.5 (23.6–71.3) 0.40 (0.15–1.11) 0.38* (0.15–0.98) — — — 
Noise exposure       
    Firearm use       
        Yes 68.2 (60.9–75.5) 1.44* (1.01–2.05) — — — 2.65* (0.12–5.19) 
        No 59.9 (53.1–66.7) Reference Reference Reference Reference Reference 
    Occupational exposure       
        Yes 72.2 (65.0–79.4) 1.87* (1.07–3.28) — — — — 
        No 58.2 (49.4–66.9) Reference Reference Reference Reference Reference 
    Leisure exposure       
        Yes 72.6 (66.6–78.6) 1.65** (1.19–2.29) — — — 3.87* (0.81–6.93) 
        No 61.6 (55.6–67.7) Reference Reference Reference Reference Reference 
Medical history       
    Diabetes       
        Yes 64.9 (56.6–73.1) 1.10 (0.71–1.70) — — — — 
        No 62.7 (56.1–69.3) Reference Reference Reference Reference Reference 
    Smoking       
        Never 62.6 (54.2–71.1) Reference Reference Reference Reference Reference 
        Former 64.4 (58.0–70.8) 1.08 (0.69–1.68) — — — — 
        Current 58.2 (43.0–73.3) 0.83 (0.47–1.45) — — — — 
    Hypertension       
        Yes 60.4 (54.6–66.2) 0.79 (0.57–1.11) — — — — 
        No 65.7 (57.9–73.6) Reference Reference Reference Reference Reference 
    Stroke       
        Yes 69.2 (53.2–85.2) 1.34 (0.69–2.59) — — — — 
        No 62.7 (57.4–67.9) Reference Reference Reference Reference Reference 

Notes: CI = confidence interval; PTA = pure tone average.

Asterisks denote level of statistical significance: *p < .05; **p < .01; ***p < .001; — not significant.

Multivariate linear regression was used to examine the association of various factors with hearing levels (speech frequency PTA in the better ear treated as a continuous dependent variable) after adjustment for all covariates in Table 2.

§

Prevalence values indicate the weighted percentage of adults with hearing loss (speech frequency PTA >25 dB in the better ear).

Univariate odds ratios indicate the odds of hearing loss relative to the designated reference group.

Multivariate odds ratios indicate the odds of hearing loss relative to the designated reference group after adjusting for all covariates in Table 2.

#

β coefficients indicate the expected change in hearing levels (in dB) for the factor relative to the designated reference group. Positive β coefficients indicate worse (greater) hearing loss associated with the studied factor, whereas negative βs indicate better hearing.

We performed additional analyses to further explore the association of age, sex, and race with hearing loss by using hearing loss as a continuous (rather than dichotomous) variable and applying different PTA frequency ranges (standard PTA [0.5–2 kHz], speech frequency PTA [0.5–4 kHz], high-frequency PTA [3–8 kHz]). Regardless of the analytic approach, age and race remained significantly associated with hearing loss. There appeared to be a gradient in the degree of hearing protection associated with black race and the studied frequency range. Compared with white participants, black participants on average had hearing thresholds that were better by −3.5 dB (95% CI: −6.6 to −0.4), −5.8 (95% CI: −8.6 to −3.1), and −11.1 (95% CI: −13.9 to −8.2) dB at standard, speech frequency, and high-frequency PTA, respectively. A similar pattern was also seen with male sex. Male sex was not associated with hearing loss at standard PTA but was associated with greater hearing loss at speech frequency (+4.2 dB [95% CI: 0.9–7.6]) and high-frequency PTA (+11.5 dB [95% CI: 7.5–15.5]). Education and noise exposure (firearm use, leisure exposure) were primarily only significantly associated with high-frequency PTA. Medical covariates including diabetes, smoking history, hypertension, and stroke were not associated with standard, speech frequency, or high-frequency PTA. The variance in hearing loss that could be explained by the covariates (R2) in each model was 0.20, 0.24, and 0.33 for standard, speech frequency, and high-frequency PTAs.

Hearing Loss and Race

We explored whether the observed protective association between black race and hearing loss could be explained by other factors. The age distributions of the black and white subcohorts were substantially different with the black cohort being younger (data not shown). To account for this potential bias, we calculated age-adjusted prevalence rates using 5-year age groups standardized against the 2000 U.S. census standard population. The age-standardized prevalence of hearing loss >25 db using the speech frequency PTA in the better ear in black participants is 44.7% (95% CI: 32.1–57.4) versus 65.6 % (95% CI: 60.6–70.6) in white participants. These prevalence rates are similar to the unadjusted prevalence rates (Table 2).

Prevalence estimates according to categories of hearing loss severity and stratified by race and sex demonstrate that black participants are more likely to have normal to mild hearing loss than white participants (Figure 1). Overall, black men had a hearing loss prevalence of 48.3% (95% CI: 36.3–60.3) versus 71.5% (95% CI: 64.8–78.3) in white men (p = .002). Similarly, the prevalence of hearing loss in black women is 39.8% (95% CI: 20.6–59.1) versus 59.0% (95% CI: 51.3–66.8) in white women (p = .03).

Figure 1.

Prevalence of hearing loss severity by sex and race using speech frequency pure tone averages in the better hearing ear in adults aged 70 years and older, National Health and Nutritional Examination Survey 2005–2006. *There were no cases of severe hearing loss in women.

Figure 1.

Prevalence of hearing loss severity by sex and race using speech frequency pure tone averages in the better hearing ear in adults aged 70 years and older, National Health and Nutritional Examination Survey 2005–2006. *There were no cases of severe hearing loss in women.

Hearing Aid Use

The overall prevalence of hearing aid use of 5 hours or more per week for individuals with hearing loss was 19.1% (95% CI: 16.2–22.0). There were substantial differences in rates of hearing aid use according to hearing loss severity (Table 3). For individuals with mild hearing loss, hearing aids were used in 3.4% (95% CI: 0.8–6.0) compared with 40.0% (95% CI: 35.1–44.8) and 76.6% (95% CI: 44.9–100) in those with moderate and severe hearing loss, respectively. In multivariate models, increased rates of hearing aid were associated with increasing hearing loss severity, higher education, and leisure noise exposure. There was no association of hearing aid use with age, sex, race, or income, but there was a nonsignificant trend between increased hearing aid use and higher income (data not shown).

Table 3.

Prevalence and Correlates of Current Hearing Aid Use for 5 hours or more per week in Individuals With Speech Frequency Pure Tone Average Greater Than 25 dB in the Better Hearing Ear, National Health and Nutritional Examination Survey 2005–2006

 Prevalence of Hearing Aid Use* (95% CI) Univariate OR†,‡ (95% CI) Multivariate OR†,§ (95% CI) 
Hearing level    
    Mild 3.4 (0.8–6.0) Reference Reference 
    Moderate 40.0 (35.1–44.8) 18.9*** (8.6–41.7) 23.0*** (9.43–56.1) 
    Severe 76.6 (44.9–100) 93.3*** (11.8–735) 95.1*** (16.3–555) 
Demographic    
    Age (y)    
        70–74 11.2 (4.2–18.2) Reference Reference 
        75–79 22.1 (11.9–32.2) 2.24 (0.72–6.96) — 
        80–84 19.5 (15.1–24.0) 1.92 (0.86–4.30) — 
        ≥85 26.5 (16.9–36.1) 2.86* (1.27–6.40) — 
    Sex    
        Female 15.1 (12.2–18.1) Reference Reference 
        Male 23.6 (18.2–29.1) 1.74* (1.14–2.64) — 
    Race    
        Non-Hispanic white 19.9 (17.1–22.7) Reference Reference 
        Non-Hispanic black 8.3 (0.6–15.9) 0.36 (0.13–1.01) — 
        Mexican or other Hispanic 12.9 (0.5–25.2) 0.59 (0.19–1.85) — 
        Other 24.4 (0–59.2) 1.30 (0.21–8.11) — 
    Education    
        <12th grade 16.2 (11.6–20.9) Reference Reference 
        High school graduate 11.9 (3.7–20.0) 0.69 (0.30–1.61) — 
        Some college or more 28.2 (19.6–36.7) 2.02* (1.17–3.49) 1.90* (1.01–3.60) 
    Household Income    
        < $20K/y 12.5 (6.7–18.3) Reference Reference 
        $20K to <$45K 19.6 (12.3–27.0) 1.70 (0.72–4.02) — 
        ≥ $45K 22.9 (13.8–32.1) 2.08 (0.96–4.49) — 
        Refused/don’t know 49.9 (1.2–98.5) 6.95 (0.91–53.0) — 
Noise exposure    
    Firearm use    
        Yes 23.6 (16.9–30.2) 1.62* (1.01–2.60) — 
        No 16.0 (13.0–19.0) Reference Reference 
    Occupational exposure    
        Yes 21.5 (14.5–28.4) 1.28 (0.77–2.15) — 
        No 17.6 (14.5–20.6) Reference Reference 
    Leisure exposure    
        Yes 29.7 (20.2–39.3) 2.03* (1.15–3.55) 2.35* (1.29–4.29) 
        No 17.3 (13.8–20.8) Reference Reference 
 Prevalence of Hearing Aid Use* (95% CI) Univariate OR†,‡ (95% CI) Multivariate OR†,§ (95% CI) 
Hearing level    
    Mild 3.4 (0.8–6.0) Reference Reference 
    Moderate 40.0 (35.1–44.8) 18.9*** (8.6–41.7) 23.0*** (9.43–56.1) 
    Severe 76.6 (44.9–100) 93.3*** (11.8–735) 95.1*** (16.3–555) 
Demographic    
    Age (y)    
        70–74 11.2 (4.2–18.2) Reference Reference 
        75–79 22.1 (11.9–32.2) 2.24 (0.72–6.96) — 
        80–84 19.5 (15.1–24.0) 1.92 (0.86–4.30) — 
        ≥85 26.5 (16.9–36.1) 2.86* (1.27–6.40) — 
    Sex    
        Female 15.1 (12.2–18.1) Reference Reference 
        Male 23.6 (18.2–29.1) 1.74* (1.14–2.64) — 
    Race    
        Non-Hispanic white 19.9 (17.1–22.7) Reference Reference 
        Non-Hispanic black 8.3 (0.6–15.9) 0.36 (0.13–1.01) — 
        Mexican or other Hispanic 12.9 (0.5–25.2) 0.59 (0.19–1.85) — 
        Other 24.4 (0–59.2) 1.30 (0.21–8.11) — 
    Education    
        <12th grade 16.2 (11.6–20.9) Reference Reference 
        High school graduate 11.9 (3.7–20.0) 0.69 (0.30–1.61) — 
        Some college or more 28.2 (19.6–36.7) 2.02* (1.17–3.49) 1.90* (1.01–3.60) 
    Household Income    
        < $20K/y 12.5 (6.7–18.3) Reference Reference 
        $20K to <$45K 19.6 (12.3–27.0) 1.70 (0.72–4.02) — 
        ≥ $45K 22.9 (13.8–32.1) 2.08 (0.96–4.49) — 
        Refused/don’t know 49.9 (1.2–98.5) 6.95 (0.91–53.0) — 
Noise exposure    
    Firearm use    
        Yes 23.6 (16.9–30.2) 1.62* (1.01–2.60) — 
        No 16.0 (13.0–19.0) Reference Reference 
    Occupational exposure    
        Yes 21.5 (14.5–28.4) 1.28 (0.77–2.15) — 
        No 17.6 (14.5–20.6) Reference Reference 
    Leisure exposure    
        Yes 29.7 (20.2–39.3) 2.03* (1.15–3.55) 2.35* (1.29–4.29) 
        No 17.3 (13.8–20.8) Reference Reference 

Notes: CI = confidence interval; OR = odds ratio.

*

Prevalence values indicate the weighted percentage of adults reporting hearing aid use > 5 hours/week.

Asterisks denote level of statistical significance level: *p < .05; **p < .01; ***p < .001; — Not significant.

Univariate odds ratios indicate the odds of hearing aid use relative to the designated reference group.

§

Multivariate odds ratios indicate the odds of hearing aid use relative to the designated reference group after adjusting for all covariates in Table 3.

Hearing level determined by speech frequency pure tone average in the better hearing ear (mild loss > 25 dB and ≤ 40 dB, moderate loss > 40 dB and ≤ 70 dB, severe loss > 70 dB).

DISCUSSION

Using a definition of hearing loss adjudicated by the World Health Organization (24), we estimated that 63.1% (95% CI: 57.4–68.8) of adults aged 70 years and older in the U.S. population are affected by hearing loss. Age, sex, and race were the principal factors associated with hearing loss, with black individuals having a hearing loss prevalence two thirds of that of white individuals in both crude and age-standardized estimates. Among individuals with hearing loss, only 19.1% reported using a hearing aid.

Our estimates of hearing loss prevalence in older adults differ somewhat from results observed in other studies. Prevalence rates reported have been 29% (>26 dB in the standard PTA in the better ear, participants >60 years), 73% (>25 dB in the speech frequency PTA in the worse ear, participants >70 years), and 60% (>25 dB in the standard PTA in the worse ear, participants 73–84 years) in the Framingham (19), Beaver Dam (17), and HealthABC (18) studies, respectively. Using similar definitions of hearing loss, prevalence from the current NHANES study would be 45%, 75%, and 61%, respectively. However, comparing prevalence estimates across different studies is difficult even when applying the same definition of hearing loss given the different demographic characteristics across cohorts particularly with regard to age and race. For example, both the Framingham cohort and Beaver Dam cohorts included few black individuals, but the HealthABC cohort included 36.3% black individuals. Age distributions and ranges also varied across these study cohorts. A strength of our study is that by applying the NHANES sample weights, our reported prevalence rates are generalizable to the entire civilian noninstitutionalized U.S. population.

Consistent with other studies, we found that age, sex, and black race were associated with hearing loss (17,18,25–27). Increasing age was associated with hearing loss across all frequency definitions of PTA but with greater hearing loss changes seen at the higher frequencies. Sex differences were also most apparent at higher frequencies consistent with other prior studies (18,26). Similarly, we found that black race was strongly associated with lower odds of hearing loss across all frequency definitions of PTA but with greater protective associations seen at higher frequency ranges.

The association of black race with lower odds of hearing loss has been well described in both epidemiological (18,28–31) and in clinical research studies (32). Current hypotheses focus on the possible protective effect of melanin in the stria vascularis (33), but experimental animal studies studying skin pigmentation and hearing loss have been inconclusive (34,35). There have not been any studies examining whether residual confounding associated with racial disparities or a potential genetic etiology could explain the protective association of black race with hearing loss. However, the role of residual confounding associated with racial disparities (e.g. higher risk of poverty, hypertensive disease in blacks) would likely bias our results toward an underestimate of the protective effect of hearing loss observed in blacks rather than toward the null hypothesis.

We did not observe significant associations of hearing loss with other cardiovascular risk factors (hypertension, smoking, diabetes, stroke) even when multiple different frequency ranges of hearing loss were considered, and hearing loss was used as a continuous variable (providing for more statistical power). Results from other large representative cohorts of older adults have also demonstrated equivocal results with regard to these risk factors (18,27,36–38). For example, diabetes mellitus was found to be positively associated with hearing loss in the HealthABC study (18) but not in the Framingham (36) and Beaver Dam studies (37). One likely explanation for these inconsistent results is that cardiovascular risk factors are only weakly associated with hearing loss, and their effects may be masked by stronger risk factors (eg, age) particularly in cohorts comprising older adults.

Among older adults with hearing loss, we estimate that approximately one fifth use a hearing aid, and this estimate is consistent with other national estimates of hearing aid use (19,39). Rates of hearing aid use differed substantially by hearing loss severity with only 3% of individuals with mild hearing loss reporting hearing aid use versus 41% in those with moderate or worse hearing loss. Interestingly, rates of hearing aid use in the United Kingdom where bilateral hearing aids are covered by the National Health Service are not higher (40), which suggests that access and affordability are not the only issues that limit hearing health care. These observations are likely indicative of general perceptions that undervalue the potential impact of hearing loss on health and functioning in aging.

There are limitations to our study. Approximately 13% of older adults who underwent the medical examination did not complete audiometric testing, and these individuals were generally older. Our prevalence estimates may, therefore, underestimate the true population prevalence of hearing loss. Our relatively modest cohort size also limited our statistical power to detect weaker associations or to explore potential interactions between race, sex, and other covariates.

Our results demonstrate that hearing loss is highly prevalent in older adults and that the nonmodifiable risk factors of age, sex, and race are the strongest determinants of hearing loss status. Although preventative strategies focused on noise exposure and other medical risk factors remain important, increasing emphasis needs to be placed on determining the genetic, epidemiological, and pathophysiological basis for the strong protective association conferred by black race. Other research focusing on clinical trials should further examine whether aural rehabilitative strategies, particularly among individuals with mild hearing loss where hearing aids are seldom used, can potentially mitigate the adverse health and functional effects associated with hearing loss in older adults.

Funding

This work was supported by the National Institute on Deafness and Other Communication Disorders (1K23DC011279 to F.L.) and a National Institute on Aging Pepper Older Americans Independence Center Research Career Development Award (F.L.).

All authors report no financial or personal conflicts of interest.

References

1.
Lin
FR
Metter
EJ
O’Brien
RJ
Resnick
SM
Zonderman
A
Ferrucci
L
Hearing loss and incident dementia
Arch Neurol
 , 
2011
 
In Press
2.
Hickson
L
Wood
J
Chaparro
A
Lacherez
P
Marszalek
R
Hearing impairment affects older people's ability to drive in the presence of distracters
J Am Geriatr Soc
 , 
2010
, vol. 
58
 (pg. 
1097
-
1103
)
3.
Viljanen
A
Kaprio
J
Pyykko
I
Sorri
M
Koskenvuo
M
Rantanen
T
Hearing acuity as a predictor of walking difficulties in older women
J Am Geriatr Soc
 , 
2009
, vol. 
57
 
12
(pg. 
2282
-
2286
)
4.
Kramer
SE
Kapteyn
TS
Kuik
DJ
Deeg
DJ
The association of hearing impairment and chronic diseases with psychosocial health status in older age
J Aging Health
 , 
2002
, vol. 
14
 
1
(pg. 
122
-
137
)
5.
Strawbridge
WJ
Wallhagen
MI
Shema
SJ
Kaplan
GA
Negative consequences of hearing impairment in old age: a longitudinal analysis
Gerontologist
 , 
2000
, vol. 
40
 
3
(pg. 
320
-
326
)
6.
Uhlmann
RF
Larson
EB
Rees
TS
Koepsell
TD
Duckert
LG
Relationship of hearing impairment to dementia and cognitive dysfunction in older adults
JAMA
 , 
1989
, vol. 
261
 
13
(pg. 
1916
-
1919
)
7.
Ives
DG
Bonino
P
Traven
ND
Kuller
LH
Characteristics and comorbidities of rural older adults with hearing impairment
J Am Geriatr Soc
 , 
1995
, vol. 
43
 
7
(pg. 
803
-
806
)
8.
Tun
PA
McCoy
S
Wingfield
A
Aging, hearing acuity, and the attentional costs of effortful listening
Psychol Aging
 , 
2009
, vol. 
24
 
3
(pg. 
761
-
766
)
9.
Dalton
DS
Cruickshanks
KJ
Klein
BE
Klein
R
Wiley
TL
Nondahl
DM
The impact of hearing loss on quality of life in older adults
Gerontologist
 , 
2003
, vol. 
43
 
5
(pg. 
661
-
668
)
10.
Viljanen
A
Kaprio
J
Pyykko
I
, et al.  . 
Hearing as a predictor of falls and postural balance in older female twins
J Gerontol A Biol Sci Med Sci
 , 
2009
, vol. 
64
 
2
(pg. 
312
-
317
)
11.
Baltes
PB
Lindenberger
U
Emergence of a powerful connection between sensory and cognitive functions across the adult life span: a new window to the study of cognitive aging?
Psychol Aging
 , 
1997
, vol. 
12
 
1
(pg. 
12
-
21
)
12.
Uchino
BN
Social support and health: a review of physiological processes potentially underlying links to disease outcomes
J Behav Med
 , 
2006
, vol. 
29
 
4
(pg. 
377
-
387
)
13.
Berkman
LF
Glass
T
Brissette
I
Seeman
TE
From social integration to health: Durkheim in the new millennium
Soc Sci Med
 , 
2000
, vol. 
51
 
6
(pg. 
843
-
857
)
14.
Lindenberger
U
Ghisletta
P
Cognitive and sensory declines in old age: gauging the evidence for a common cause
Psychol Aging
 , 
2009
, vol. 
24
 
1
(pg. 
1
-
16
)
15.
Van
EE
Van
CG
Van
LL
The complexity of age-related hearing impairment: contributing environmental and genetic factors
Audiol Neurootol
 , 
2007
, vol. 
12
 
6
(pg. 
345
-
358
)
16.
Mulrow
CD
Aguilar
C
Endicott
JE
, et al.  . 
Quality-of-life changes and hearing impairment. A randomized trial
Ann Intern Med
 , 
1990
, vol. 
113
 
3
(pg. 
188
-
194
)
17.
Cruickshanks
KJ
Wiley
TL
Tweed
TS
, et al.  . 
Prevalence of hearing loss in older adults in Beaver Dam, Wisconsin. The Epidemiology of Hearing Loss Study
Am J Epidemiol
 , 
1998
, vol. 
148
 
9
(pg. 
879
-
886
)
18.
Helzner
EP
Cauley
JA
Pratt
SR
, et al.  . 
Race and sex differences in age-related hearing loss: the Health, Aging and Body Composition Study
J Am Geriatr Soc
 , 
2005
, vol. 
53
 
12
(pg. 
2119
-
2127
)
19.
Gates
GA
Cooper
JC
Jr.
Kannel
WB
Miller
NJ
Hearing in the elderly: the Framingham cohort, 1983–1985. Part I. Basic audiometric test results
Ear Hear
 , 
1990
, vol. 
11
 
4
(pg. 
247
-
256
)
20.
Centers for Disease Control and Prevention
National Centers for Health Statistics. The National Health and Nutrition Examination Survey Questionnaire and Exam Protocol, 2010
 
21.
Centers for Disease Control and Prevention
National Centers for Health Statistics. The National Health and Nutrition Examination Survey. Audiometry manual 2005-2006, 2010
 
Web site: http://www.cdc.gov/nchs/data/nhanes/nhanes_05_06/AU.pdf. Accessed October 10, 2010
22.
Clark
JG
Uses and abuses of hearing loss classification
ASHA
 , 
1981
, vol. 
23
 
7
(pg. 
493
-
500
)
23.
Centers for Disease Control and Prevention
National Centers for Health Statistics. The National Health and Nutrition Examination Survey Analytic and Reporting Guidelines
  
24.
World Health Organization Prevention of Blindness and Deafness (PBD) Program
Prevention of Deafness and Hearing Impaired Grades of Hearing Impairment
 
25.
Cooper
JC
Jr.
Gates
GA
Hearing in the elderly—the Framingham cohort, 1983-1985. Part II: Prevalence of central auditory processing disorders
Ear Hear
 , 
1991
, vol. 
12
 
5
(pg. 
304
-
311
)
26.
Moscicki
EK
Elkins
EF
Baum
HM
McNamara
PM
Hearing loss in the elderly: an epidemiologic study of the Framingham Heart Study Cohort
Ear Hear
 , 
1985
, vol. 
6
 
4
(pg. 
184
-
190
)
27.
Brant
LJ
Gordon-Salant
S
Pearson
JD
, et al.  . 
Risk factors related to age-associated hearing loss in the speech frequencies
J Am Acad Audiol
 , 
1996
, vol. 
7
 
3
(pg. 
152
-
160
)
28.
Agrawal
Y
Platz
EA
Niparko
JK
Prevalence of hearing loss and differences by demographic characteristics among US adults: data from the National Health and Nutrition Examination Survey, 1999-2004
Arch Intern Med
 , 
2008
, vol. 
168
 
14
(pg. 
1522
-
1530
)
29.
Cooper
JC
Jr.
Health and Nutrition Examination Survey of 1971-75. Part I: Ear and race effects in hearing
J Am Acad Audiol
 , 
1994
, vol. 
5
 
1
(pg. 
30
-
36
)
30.
Jerger
J
Jerger
S
Pepe
P
Miller
R
Race difference in susceptibility to noise-induced hearing loss
Am J Otol
 , 
1986
, vol. 
7
 
6
(pg. 
425
-
429
)
31.
Ishii
EK
Talbott
EO
Race/ethnicity differences in the prevalence of noise-induced hearing loss in a group of metal fabricating workers
J Occup Environ Med
 , 
1998
, vol. 
40
 
8
(pg. 
661
-
666
)
32.
Garber
SR
Turner
CW
Creel
D
Witkop
CJ
Jr.
Auditory system abnormalities in human albinos
Ear Hear
 , 
1982
, vol. 
3
 
4
(pg. 
207
-
210
)
33.
Barrenas
ML
Axelsson
A
The development of melanin in the stria vascularis of the gerbil
Acta Otolaryngol
 , 
1992
, vol. 
112
 
1
(pg. 
50
-
58
)
34.
Bartels
S
Ito
S
Trune
DR
Nuttall
AL
Noise-induced hearing loss: the effect of melanin in the stria vascularis
Hear Res
 , 
2001
, vol. 
154
 
1–2
(pg. 
116
-
123
)
35.
Yanz
JL
Herr
LR
Townsend
DW
Witkop
CJ
Jr.
The questionable relation between cochlear pigmentation and noise-induced hearing loss
Audiology
 , 
1985
, vol. 
24
 
4
(pg. 
260
-
268
)
36.
Gates
GA
Cobb
JL
D’Agostino
RB
Wolf
PA
The relation of hearing in the elderly to the presence of cardiovascular disease and cardiovascular risk factors
Arch Otolaryngol Head Neck Surg
 , 
1993
, vol. 
119
 
2
(pg. 
156
-
161
)
37.
Dalton
DS
Cruickshanks
KJ
Klein
R
Klein
BE
Wiley
TL
Association of NIDDM and hearing loss
Diabetes Care
 , 
1998
, vol. 
21
 
9
(pg. 
1540
-
1544
)
38.
Cruickshanks
KJ
Klein
R
Klein
BE
Wiley
TL
Nondahl
DM
Tweed
TS
Cigarette smoking and hearing loss: the epidemiology of hearing loss study
JAMA
 , 
1998
, vol. 
279
 
21
(pg. 
1715
-
1719
)
39.
Popelka
MM
Cruickshanks
KJ
Wiley
TL
Tweed
TS
Klein
BE
Klein
R
Low prevalence of hearing aid use among older adults with hearing loss: the Epidemiology of Hearing Loss Study
J Am Geriatr Soc
 , 
1998
, vol. 
46
 
9
(pg. 
1075
-
1078
)
40.
Davis
A
Smith
P
Ferguson
M
Stephens
D
Gianopoulos
I
Acceptability, benefit and costs of early screening for hearing disability: a study of potential screening tests and models
Health Technol Assess
 , 
2007
, vol. 
11
 
42
(pg. 
1
-
294
)

Author notes

Decision Editor: Darryl Wieland, PhD, MPH