The Prevalence of Hearing Loss and Provision With Hearing Aids in the Gutenberg Health Study

Background: Hearing is a basic ability that is needed for participation in daily life. Hearing loss often greatly reduces a person’s quality of life. Nevertheless, epidemiological data on the prevalence of hearing disorders in Germany are sparse. This study investigated the prevalence of hearing disorders and the actual provision with hearing aids.

Methods: The Gutenberg Health Study (GHS) is a representative cohort study carried out at the Department of Medicine of Mainz University to investigate the health of the population of the city of Mainz and the neighboring Mainz-Bingen district. The GHS participants underwent pure-tone audiometry of each ear independently.

Results: Tone audiometry data from a total of 5024 participants were evaluated. The prevalence of hearing loss—regardless of severity—in at least one ear was 40.6% in this study population. The hearing loss was mild in 22.5% of the participants, moderate in 8.3%. Some 2.8% had severe hearing loss. In this group, the women had better hearing than the men (by a mean 4.3 dB). The prevalence of hearing disorders rose with increasing age. The minimum tone audiometry conditions for bilateral hearing aid provision—as defined in the relevant German guideline—were met in 47.7% of the participants. Only 7.7% of the participants already had hearing aids for both ears. The discrepancy between the prevalence of hearing loss and the indication for provision with hearing aids arises from differences in how hearing loss was ascertained and the indications set.

Conclusion: The prevalence of hearing loss was high, at 40.6%. Regular hearing tests should be recommended for the general German population, starting at no later than 60 years of age.

Estimates put the number of people affected by hearing loss at approximately 1.5 billion (1). Moreover, due to demographic change, one must assume that the number of hearing disorders will continue to steadily rise. Hearing is a basic ability required for participation in daily life. Loss of hearing is associated not only with a significant reduction in quality of life but also impairs everyday functioning, particularly in terms of participation, and leads to isolation and stress (2, 3, 4). There is only a limited number of epidemiological studies on the prevalence of hearing disorders in adults and the prevalence of hearing aid provision in Germany.

Although an inadequately treated hearing disorder can result in particular in the social isolation of older individuals (5, 6), only a sparse number of national studies are available. The 2019 review article by Löhler et al. found six studies relating to data on hearing disorders in Germany. A broad range was seen here in the reporting of hearing loss prevalence (between 16% and 25%) with no standardized definition of hearing loss (7). Only two studies provided data on hearing aid provision. According to epidemiological studies on hearing status in northwest Germany (HÖRSTAT), the prevalence of hearing loss, as defined by the World Health Organization classification, was estimated to be 16% when extrapolated to the national level (8). The percentage of participants with hearing aids was 6.5%. In the investigation conducted by Sohn and Jörgenshaus (9), 19% had a hearing level (HL) > 40 dB). Only 2% of respondents had a hearing aid and only 57% of these used their devices. It is believed that only 37% of people with a hearing disorder in Germany wear a hearing aid (10).

The aim of this study was to determine the prevalence of hearing disorders and the provision (or underprovision) of hearing aids in a large population-based and randomly selected cohort. It is one of the largest studies using pure-tone audiometry data in Germany.

Methods

The Gutenberg Health Survey (GHS) is a large, ongoing population-based study that was conceived as a monocentric, prospective cohort study. It was initiated in 2007 at the Department of Medicine of Mainz University, Germany. The study aimed to investigate the population of the city of Mainz and the neighboring Mainz‒Bingen district. Approval has been granted by the Ethics Committee of the Rhineland-Palatinate Medical Association (Ref. No. 837.020.07). The population sample was randomly selected from data held at the residents’ registration office and classified according to place of residence for each age decade. Exclusion criteria included physical and mental disabilities that could prevent participants from attending the study center. Residents with insufficient knowledge of the German language were also excluded. In accordance with the Declaration of Helsinki, written informed consent was obtained from all subjects prior to their participation in the study. During the period 2017–2020 (10-year follow-up [10-FU]), extensive otological examinations were included in the broadly diverse and interdisciplinary investigations. A detailed description of the study design has already been published elsewhere (11).

The validity of audiological examinations was ensured by implementing a standard operating procedure (SOP). All study contacts and examinations of participants took place on the premises of the Department of Medicine of Mainz University. The supervising study assistants received (further) training from certified audiologists in the Ear, Nose, and Throat (ENT) Department focusing on communication disorders at Mainz Medical University.

Participants were asked about otological symptoms. Otoscopy followed by pure-tone audiometry for both air and bone conduction were carried out separately for each ear. A detailed description can be found in the eMethods.

To investigate the prevalence of hearing impairment in the greater Mainz area, percentage hearing loss was determined on the basis of the pure-tone audiogram according to Röser’s four-frequency table, which was developed in 1973 and is commonly used in Germany (12). Percentage hearing loss is obtained by adding up the four subcomponents:

• 0–19%: Normal hearing
• 20–39%: Mild hearing loss
• 40–59%: Moderate hearing loss
• 60–79%: Severe hearing loss
• 80–99%: Profound hearing los
• 100%: Deafness.

A corresponding hearing aid indication was defined for the study—in accordance with the guidelines of the German Federal Joint Committee on the prescription of medical aids—in the case of hearing loss on pure-tone audiometry of at least 30 dB in at least one of the test frequencies between 500 and 4000 Hz. Additional comprehension rates based on speech audiometry using the Freiburg monosyllabic test were not available.

Socioeconomic status was calculated according to Lampert and Kroll (13). The total score ranges between 3 and 21 and is made up of the attributes “highest educational level,” “household income,” and “occupational position held.”

Means were compared using the t-test and medians using the Mann–Whitney U test. Influencing factors were determined with logistic regression models. Dichotomous variables were investigated using Pearson’s Chi-squared test.

All statistical analyses were performed using R version 3.6.1 (2019–07–05).

Results

In 2017, 10,000 people were invited for the 10-FU of the Gutenberg Health Study. Of these, 8731 took part. It was not possible to record ENT data in 3614 participants due to staff shortages. Likewise, 93 participants lacking data in the 0.5-kHz, 1-kHz, 2-kHz, or 4-kHz frequencies were also excluded from the study. Overall, complete data on pure-tone audiometry were available for 5024 subjects, of which 2433 were female (48.4 %) and 2591 (51.6%) male. There were no significant differences with regard to age (p = 0.86), sex (p = 0.2), and socioeconomic status (p = 0.57) between participants and non-participants. A total of 4990 individuals had received information on hearing aid provision.

Prevalence of hearing loss according to Röser, 1973 (12)

The overall mean prevalence of hearing loss—irrespective of severity—in the study population was 34.5% (age as mean and standard deviation: 61.2 ± 13.4 years; minimum and maximum: 25–86 years). Hearing loss in at least one ear was found in 40.6% of participants and bilateral hearing loss in 28.5%. On average, women had significantly better hearing compared to men (mean of 4.3 dB as well as 2.6% less hearing loss according to Röser [12]; U test: p < 0.0001).

In the total population, 22.5% had mild hearing loss on the right side. A total of 8.3% of study participants were in the moderate hearing loss range. Severe hearing loss was diagnosed in 2.8% of individuals. Profound hearing loss was found in 0.9% and deafness in 0.1% of participants. There were no significant differences to the left side (paired t-test: p = 0.59). The full results are given in Table 1. A graphical representation of auditory thresholds is provided in Figure 1. The prevalence of tinnitus in this study population was 25.5% (1230/5024). Distress due to tinnitus was reported to be low by 35.1% of individuals (n = 302), slight by 30.3% (n = 261), moderate by 16.7% (n = 144), noticeable by 10.6% (n = 91), high by 4.8% (n = 41), and extreme by 2.4% (n = 21).

Figure 1

Pure-tone audiogram across the main cohort

Table 1

Prevalence of hearing impairment/hearing loss by weighting characteristics and sex

Prevalence of hearing loss according to Röser, 1973 (12) and age

The prevalence of hearing disorders rose with increasing age. In the cohort of study participants aged between 55 and 59 years, 16.7% were found to have hearing loss. In the 75- to 79-year-old cohort, 71.1% were hard of hearing. Table 2 shows the precise age distribution of hearing loss. The effect of age on hearing loss was modeled with linear regression. As part of this, an interaction term was included in the model at the age of 58 years, thereby enabling an adjustment for the change in slope from this point (p < 0.0001; Figure 2). Figure 3 shows the frequency distribution for the prevalence of hearing loss (according to Röser [12] of more than 20%) by age. Prevalence according to the WHO is given in the eMethods Section.

Figure 2

Mean hearing loss in percent by age

Figure 3

Frequency distribution for the prevalence of hearing loss by age

Table 2

Prevalence of hearing impairment/hearing loss according to Röser with age distribution

Hearing aids and hearing aid indication

The reported prevalence of bilateral hearing aid provision in the study population was 7.7% (383/4990). Pure-tone audiometric hearing loss in one ear of at least 30 dB in at least one test frequency between 500 and 4000 Hz was found in 53.9% (2708 /5024) of study participants in the right ear and in 57.1% (2870/5024) of study participants in the left. In all, 47.4% (2383/5024) of individuals met the minimum requirements regarding pure-tone audiometric hearing loss for bilateral hearing aid provision. The association between bilateral hearing loss and sex (logistic regression model: females; p < 0.0026) as well as age (p < 0.0001) was significant.

Hearing aid provision and socioeconomic status

Across all participants, the prevalence of hearing loss was significantly higher in low socioeconomic status (SES) (p < 0.001). Figure 4 shows mean hearing loss according to Röser (12) in percent for the respective socioeconomic status. As SES increases, the indication for a hearing aid significantly decreases, that is to say, the minimum requirement in terms of pure-tone audiometric hearing loss for hearing aid provision is significantly less frequently met with higher SES (p < 0.001). There is no significant association between actual hearing aid provision and socioeconomic status (logistic regression model: p = 0.26; Figure 5).

Figure 4

Moderate hearing loss according to Röser, 1973 (12) in percent

Figure 5

Hearing aid indication and provision

Discussion

According to the WHO’s 2021 “World Report on Hearing,” hearing disorders are among the third most frequent quality of life-impairing disorders in industrialized countries (1). Despite this, data on the prevalence of hearing disorders in Germany are sparse. Thus, this study investigated the prevalence of hearing disorders as well as actual provision with hearing aids.

The overall mean prevalence of hearing loss was 34.5%. Hearing loss in at least one ear was found in 40.6% of participants. As expected, the prevalence of hearing disorders rises with increasing age.

In Germany, hearing loss in old age has been hitherto insufficiently diagnosed and treated (14). Already back in 2019, Löhler et al. called for screening by all physicians and subsequent further specialist diagnostic evaluation. Early diagnosis is also important with regard to improving the acceptance of hearing aids. Successful hearing aid fitting is challenging in the case of a long history of untreated hearing loss. The assumption here is that the ability to perceive and process speech in the brain is progressively reduced in the absence of stimulation (late onset deprivation) (5).

In line with the guidelines of the Federal Joint Committee on the prescription of medical aids, 47.4% of participants met the minimum requirement in terms of pure-tone audiometric hearing loss for bilateral hearing aid provision. However, only 7.7% had actually been fitted with bilateral hearing aids. Although a rate of speech intelligibility in speech audiometry was not available to evaluate the indication for a hearing aid, the pure-tone audiometry data suggest massive underprovision. The discrepancy between the indication/minimum requirement for hearing aids and the reported prevalence of hearing loss is striking. However, this relation, which appears to be paradoxical at first glance, can be explained by the varying calculations. While for a hearing aid indication a hearing loss of at least 30 dB is defined as an absolute number in one of the corresponding frequencies, the percentage hearing loss according to Röser (12) is determined as the sum value of hearing loss between 0.5 and 4 kHz with different weighting.

The 2015 study conducted by Emmett et al. showed an association between hearing loss and low educational attainment, low income, and unemployment (15). The literature discusses noise in the workplace and during recreation, varying lifestyles, and substances that are harmful to hearing as causative in this regard. Likewise in this study, low socioeconomic status is associated with a significantly higher prevalence of hearing loss (p < 0.001).

Previous data on the prevalence of hearing disorders in Germany are sparse. In 2019, Löhler et al. published a systematic review on the prevalence of hearing loss (7). In the 2012 German Health Update study (Gesundheit in Deutschland aktuell 2012, GEDA 2012) carried out by the Robert Koch Institute, over 20% of men and women reported suffering from hearing loss (16). The study was conducted as a telephone survey. One must assume that there is a discrepancy between reported hearing disorders and those confirmed on pure tone-audiometry, since hearing disorders are often underestimated by the affected individuals themselves. In their epidemiological studies, von Gablenz et al. found a prevalence of hearing loss of approximately 16% in adults according to previous WHO criteria (8, 17). For these studies, they collected tone audiometry data, whereby 8% of participants were tested in private rooms. In 2008, Neubauer and Gmeiner determined a prevalence of more than 10% in the over 70-year-old age group according to the International Statistical Classification of Diseases and Related Health Problems (ICD). In the data we collected, the prevalence of hearing loss was higher, whereby the mean age was 61.2 years—with a larger number of study participants in the over 50-year-old age cohorts. A marked increase in hearing loss could be seen from the age of 58 years. Since the younger age cohorts are underrepresented in the study population, the data are not representative of the whole of Germany without weighting. In the study conducted by Didczuneit-Sandhop et al. in 2021, the mean age was 74.4 years and 97% of participants (181/186) suffered from hearing loss (18). Of those with hearing loss, 77% did not own a hearing aid, and underprovision was significantly higher if there was no audiologist or ENT physician in the local area. An international comparison reveals that the prevalence found in our study was higher than in the US, where—according to reports from 2016—hearing loss directly affects 23% of Americans (19). In India, the range in reported figures was also broad, with the prevalence put at 6–26.9% (20).

One major strength of our study is the high number of participants. As part of the Gutenberg Health Study, it was possible to obtain representative results with 5024 individuals in all age cohorts. Furthermore, the pure-tone audiometry described here enabled high-quality data to be gathered. Examinations were carried out by personnel that had received intensive training.

In addition, a comorbidity index was developed based on the total score for nine variables: chronic obstructive pulmonary disease (COPD), diabetes, hypertension, myocardial infarction, stroke, cancer, depression module PHQ-9, generalized anxiety disorder, and chronic kidney disease. On average, subjects had a comorbidity index of 0.93 ± 0.90. In the non-responder analysis, there was no significant difference between responders and non-responders. The regression models were adjusted with the index. This adjustment had no influence on other effects.

One limitation of the study is that speech audiometry—performed separately for each ear—is required in order to precisely establish a possible hearing aid indication, meaning that in this study, only the minimum requirement with regard to hearing loss on pure-tone audiometry was obtained and the possible hearing aid indication was estimated. Likewise, no data were gathered on the causes of the already known hearing disorders, and no information was included regarding risk factors such as noise pollution. Despite the abovementioned weaknesses, this is the first study to date of this size in Germany using standardized pure-tone audiometry data.

Hearing loss is associated not only with a loss of communication, education, and social interaction—a link between hearing loss and dementia has already been demonstrated by a number of studies. In the 2020 report published by the Lancet Commission, hearing impairment is given as the greatest modifiable risk for dementia in middle-aged people compared to people without a hearing impairment (21). It is believed that the wearing of a hearing aid is able to counteract the decline in cognitive abilities. Hearing disorders are also associated with a higher risk for the development of depression (22, 23). Moreover, patients with severe hearing loss exhibit more pronounced cognitive deficits (24). In older individuals, hearing loss is linked to a significantly higher probability of falls (25). Hearing aids appear to improve spatiotemporal orientation in older adults (26). These findings represent additional reasons why greater emphasis should be placed on screening for hearing disorders in Germany.

Practical conclusion

Screening for hearing disorders is of immense importance. The prevalence of hearing loss is greatly underestimated. Too little attention is currently paid to the need for early detection and treatment. Regular hearing tests should urgently be carried out for the general German population as part of preventive care, starting at no later than 60 years of age.

Funding

The Gutenberg Health Study (GHS) is funded by the of Rhineland-Palatinate government (Stiftung Rheinland-Pfalz für Innovation [Rhineland-Palatinate Foundation for Innovation]; contract No. 961–386261/733), the research program “Wissen schafft Zukunft” (Knowledge Builds the Future), and the Research Center for Translational Vascular Biology (CTVB) of the Johannes Gutenberg University Mainz, as well as through a contract with Boehringer Ingelheim and PHILIPS Medical Systems, including an unrestricted grant for the GHS.

Conflict of interest statement

Frau Bohnert is an honorary member of the board of the BIAP (Bureau Internationale d’Audiophonologie) and the advisory board of the German Audiological Society (Deutsche Gesellschaft für Audiologie, DGA). She is a member of the Pediatric Advisory Board of Sonova, Switzerland, and received third-party funding for research purposes from this company.

Prof. Rader is honorary chairman and secretary of the specialist society “Arbeitsgemeinschaft Deutschsprachiger Audiologen, Neurootologen und Otologen (ADANO)” (Working Group of German-speaking Audiologists, Neurootologists, and Otologists). He received study funding from Cochlear Deutschland and MED-EL Deutschland.

Prof. Wild received funding from the German Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung; BMBF 01EO1003 and 01EO1503). He is Principle Investigator at the German Center for Cardiovascular Research (Deutsches Zentrum für Herz-Kreislauf-Forschung, DZHK) and head of the DIASyM research core (BMBF 161L0219). He received a consultancy fee from Boehringer Ingelheim.

Prof. Münzel is Principal Investigator at the German Center for Cardiovascular Research (DZHK).

The remaining authors declare that no conflict of interest exists.

Manuscript received on 25 April 2022, revised version accepted on 18 November 2022.

Translated from the original German by Christine Rye.

Corresponding author
Dr. med. Katharina Bahr

Hals-, Nasen-, Ohrenklinik und Poliklinik, Universitätsmedizin Mainz

Langenbeckstr. 1, 55131 Mainz, Germany

Cite this as:
Döge J, Hackenberg B, O‘Brien K, Bohnert A, Rader T, Beutel ME, Münzel T, Pfeiffer N, Nagler M, Schmidtmann I, Wild PS, Matthias C, Bahr K: The prevalence of hearing loss and provision with hearing aids in the Gutenberg Health Study. Dtsch Arztebl Int 2023; 120: 99–106. DOI: 10.3238/arztebl.m2022.0385

►Supplementary material

eMethods:
www.aerzteblatt-international.de/m2022.0385

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