Presbycusis or age-related hearing loss is a bilaterally symmetric sensorineural hearing loss associated exclusively with age, excluding any other causes of hearing loss. Presbycusis is very relevant because of its high prevalence, and its consequences (e.g., alterations in communication, social isolation, depression, dementia), and the economic impact. This paper reports the first attempt to estimate the prevalence of presbycusis in an otologically normal population, i.e., without previous ear disease, exposure to noise, or potentially ototoxic substances, or familial hearing loss.
MethodsA total of 4290 subjects from 5 to 90 years old were included in the study.
ResultsNo statistically significant differences were found between right and left ear, nor between males and females, in any of the age groups. Presbycusis was detected over 60 years following the WHO classification; although the results vary depending on the classification used. Moderate hearing loss (≥ 41dB) was detected in the population over 72 years. None of the subjects had severe or profound hearing impairment. The prevalence of presbycusis increased with age, being 100% in individuals aged 80 years and older. The prevalence of presbycusis is highly variable depending on the pure-tone averaged frequencies and the classification system used; therefore, a common classification system should be used.
ConclusionsAn otologically normal population is needed to establish the prevalence of presbycusis as in non-screened populations it is the hearing level including all types of hearing loss that is measured, but not presbycusis itself.
La presbiacusia o pérdida auditiva relacionada con la edad, es una hipoacusia neurosensorial bilateral y simétrica asociada exclusivamente a la edad. La presbiacusia es muy relevante debido a su alta prevalencia y sus consecuencias (alteraciones en la comunicación, aislamiento social, depresión, demencia) y el impacto económico. Este es el primer trabajo que aporta datos sobre la prevalencia de la presbiacusia en una población otológicamente normal, es decir, sin enfermedad auditiva previa, exposición a ruido o sustancias potencialmente ototóxicas o pérdida de audición familiar.
Material y métodosUn total de 4.290 sujetos de 5 a 90 años de edad fueron incluidos en el estudio.
ResultadosNo se encontraron diferencias entre el oído derecho y el izquierdo, ni entre varones y mujeres. La presbiacusia se detectó a partir de los 60 años siguiendo la clasificación de la OMS, aunque los resultados varían dependiendo de la clasificación utilizada. Se detectó hipoacusia moderada (≥41dB) en la población mayor de 72 años. Ninguno de los sujetos tenía hipoacusia grave o profunda. La prevalencia de presbiacusia aumentó con la edad, siendo del 100% en individuos de 80 años o más. La prevalencia de la presbiacusia es altamente variable dependiendo de las frecuencias promediadas y del sistema de clasificación utilizado; por lo tanto, debería utilizarse un sistema de clasificación común.
ConclusionesPara establecer la prevalencia de la presbiacusia se necesita una población otológicamente normal ya que, si la población no está cribada, lo que se mide es la hipoacusia que incluye todos los tipos de pérdida auditiva, pero no la presbiacusia de forma aislada.
Presbycusis, also known as age-related hearing loss (ARHL), is defined as a gradual bilaterally symmetric sensorineural hearing loss associated with ageing that is due to progressive degeneration of the cochlea and auditory pathways.
Presbycusis is one of the most prevalent chronic pathologies in subjects over 65 years; and is the leading cause of acquired hearing loss in the adult population followed by noise-induced hearing loss. Presbycusis of a moderate or greater degree affects communication and can contribute to social isolation,1 depression and dementia.2–5
There has been an increase in the percentage of the population aged 65 years or over. In Europe, 19.2% of the population is over 65 years old.6 With this population change, the prevalence of presbycusis is expected to be increased considerably. Roth et al.7 performed a review in order to determine the prevalence of ARHL in Europe. Most studies have been conducted in the northern Europe, and only two studies in the southern Europe, Italy.8,9 Among these studies there was great variability between age groups, the way they measured hearing loss, and how the population was selected. Thus, the prevalence of presbycusis in Europe has not been established yet.
This paper reports the results of the first attempt to estimate the prevalence of age-related hearing loss in Spain. The recommended selection and classification criteria have been followed.
Material and methodsData was collected from a total of 4290 subjects recruited from healthy volunteers living in the Madrid region (Spain), which encompasses a geographical area representative of the Spanish population. Their ages ranged from 5 to 90 years old; and they were divided into age groups at 5-year and 10-year intervals. The study was conducted between 2015 and 2017.
Inclusion criteria for participation in the study include those contained in the ISO 7029 for otologically normal persons10: person in a normal state of health who is free from all signs or symptoms of ear disease and from obstructing wax in the ear canal and who has no history of undue exposure to noise, exposure to potentially ototoxic substances or familial hearing loss.
All the subjects’ suitability for inclusion was evaluated through interview and physical examination in the otolaryngology clinic in accordance with ISO 389-9.11
The study was approved by the institutional ethics committee and was conducted in accordance with the Helsinki Declaration. Informed consent was obtained from all patients.
Pure-tone hearing threshold levels (0.125–8kHz) were determined by using an Interacoustics Clinical Audiometer AC40 (Interacoustics A/S, Denmark) with Telephonics TDH-39P supra-aural earphones (Telephonics Co., Farmingdale, USA). All audiometric testing equipment was calibrated according to ISO 389-5.12 All tests were performed in a soundproof chamber meeting the ISO 8253-1.13 Thresholds were determined according to the ascending method13 using a 5-dB step size. Thresholds are given as decibel Hearing Level (dB HL).
Hearing impairment was classified according to the pure-tone average (PTA) of hearing threshold levels at 0.5, 1, 2 and 4kHz according to the World Health Organisation (WHO),14 the European (EU) Working Group on Genetics and Hearing Impairment,15 the Bureau International d’Audiophonologíe (BIAP),16 and the Global Burden of Disease (GBD)17 classifications; and PTA at 0.5, 1, and 2kHz according to the American Speech-Language-Hearing Association (ASHA) classification18 (Table 1).
Grades of hearing impairment according to the World Health Organisation (WHO), the European (EU) Working Group on Genetics and Hearing Impairment, the Bureau International d’Audiophonologíe (BIAP), the Global Burden of Disease (GBD), and the American Speech-Language-Hearing Association (ASHA) classifications. The values are the pure tone averages at 0.5, 1, 2 and 4kHz (PTA0.5,1,2kHz in the ASHA classification), and are in dB Hearing Level (dB HL).
| Categorization | WHO | EU | BIAP | GBD | ASHA |
|---|---|---|---|---|---|
| Normal | ≤25 | ≤20 | ≤20 | ≤15 | |
| Slight | 16–25 | ||||
| Mild | 26–40 | 21–39 | 21–40 | 20–34 | 26–40 |
| Moderate | 41–60 | 40–69 | 1st degree 41–55 | 35–49 | 41–55 |
| Moderately severe | 2nd degree 56–70 | 50–64 | 56–70 | ||
| Severe | 61–80 | 70–94 | 1st degree 71–80 | 65–79 | 71–90 |
| 2nd degree 81–90 | |||||
| Profound | ≥81 | ≥95 | Very severe:1st degree 91–100 | 80–94 | ≥91 |
| 2nd degree 101–110 | |||||
| 3rd degree 111–119 | |||||
| Total hearing loss (cofosis) | 120+ |
Data was analysed using the Statistical Package for Social Science (SPSS), version 15.0. The statistical analysis was carried out using the ANOVA test and Tukey test for multiple group comparisons. The comparison between age and gender variables was evaluated using the χ2 test. A three-way ANOVA test was applied with gender, age, and frequency as independent variables, and thresholds as the dependent variable. A p-value of <0.05 was accepted as the statistical significance level.
ResultsA total of 4290 subjects met the inclusion criteria. There were 2130 males (49.65%), and 2160 females (50.35%). The group composition was: 5–14 year group (n=561); 15–24 year group (n=948); 25–34 year group (n=1130); 35–44 year group (n=703); 45–54 year group (n=309); 55–64 year group (n=291); 65–74 year group (n=210); 75–84 year group (n=126); 85–90 year group (n=12) (Table 2). The older age groups were also divided in 5-year intervals (Fig. 1). As the age group was older, the sample size was smaller, due to the difficulty in meeting the selection criteria.
Prevalence of age-related hearing loss. The values are the pure tone averages at 0.5, 1, 2 and 4kHz (PTA0.5,1,2kHz in the ASHA classification), and are in dB Hearing Level (dB HL).
| Aye group, years (no.) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Categorization | 5–14(N=561) | 15–24(N=948) | 25–34(N=1130) | 35–44(N=703) | 45–54(N=309) | 55–64(N=291) | 65–74(N=210) | 75–84(N=126) | 85–90(N=12) |
| 16–20dB HL | |||||||||
| PTA0.5,1,2,4kHz | 5.9% (33) | 1.2% (12) | 1.8% (21) | 2.5% (18) | 19% (60) | 25.8% (75) | 25.7% (54) | 11.9% (15) | |
| PTA0.5,1,2kHz | 8% (45) | 1% (9) | 0.8% (9) | 2.1% (15) | 20% (63) | 16.5% (48) | 21.5% (45) | 21.4% (27) | |
| 21–25dB HL | |||||||||
| PTA0.5,1,2,4kHz | 0.5% (3) | 6.8% (21) | 12.4% (36) | 17.1% (36) | 4.7% (6) | ||||
| PTA0.5,1,2kHz | 5.8% (18) | 9.3% (27) | 24.3% (51) | 19% (24) | |||||
| 26–40dB HL | |||||||||
| PTA0.5,1,2,4kHz | 6.2% (18) | 31.4% (66) | 54.7% (69) | 75% (9) | |||||
| PTA0.5,1,2kHz | 4.1% (12) | 14.3% (30) | 38.1% (48) | 75% (9) | |||||
| 41–55dB HL | |||||||||
| PTA0.5,1,2,4kHz | 2.8% (6) | 16.5% (21) | 25% (3) | ||||||
| PTA0.5,1,2kHz | 7.1% (9) | 25% (3) | |||||||
No statistically significant differences were found between right and left ear, nor between males and females, in any of the age groups.
Mild hearing loss was detected in population over 60 years according to the WHO classification; 44 years according to EU, BIAP and GBD classifications; and 59 years of age according to the ASHA classification.
Moderate hearing loss was detected in population over 72 years according to the WHO, EU, BIAP, and ASHA classifications; and 68 years according to GBD classification. Moderate hearing loss was the highest hearing loss detected (55dB HL at PTA 0.5,1,2,4kHz; and 48dB HL at PTA 0.5,1,2kHz). None of the subjects had severe or profound hearing impairment.
We found that 8% of subjects between 5 and 14 years of age had a slight hearing loss based on the ASHA criteria (16–25dB). This percentage was less than 1% between 15 and 35 years, and gradually increases over 35 years.
One way to compare all classifications would be by dividing the degrees of hearing loss into 16–20dB; 21–25dB; 26–40dB; and 41–55dB HL (Table 2). The prevalence of presbycusis is highly variable depending on the pure-tone averaged frequencies (PTA0.5,1,2,4kHz, or PTA0.5,1,2kHz). In addition, it will also depend on the classification used.
Fig. 1 shows the prevalence of presbycusis, in 5-year age groups, according to WHO criteria. The prevalence of ARHL increases with age, being 100% in individuals aged 80 years and older (Fig. 1).
DiscussionA large number of classification systems are used to categorise hearing loss severity. International classification systems such as those of the WHO, the EU Working Group, the BIAP, the GBD, and the ASHA differ considerably (Table 1). These differing systems make it difficult for a meaningful comparison, and using one or another classification can make our data vary considerably. Roth et al.7 support the need for standardised collection of epidemiological data on hearing loss. In this paper we have mainly exposed the data based on the WHO classification, which is the one proposed by Roth7 with whom we agree.
It should be noted that no classification takes into account frequencies above 4kHz. Nevertheless, frequencies up to 6kHz, and even 8kHz may have importance in understanding words, especially in background noise environments.19–21
Presbycusis is defined as a progressive bilateral and symmetrical sensorineural hearing loss associated with ageing. If the hearing loss does not meet these criteria, it may be another type of hearing loss different from presbycusis.
Large cohorts seeking to establish the prevalence of ARHL, like the Framingham Heart Study Cohort,22,23 the Epidemiology of Hearing Loss Study in Beaverdam,24 and the Rotterdam Study,25 included an unscreened older population. In non-screened populations we are measuring the hearing level in the general population, including all types of hearing loss, but not presbycusis itself. In addition, it would be necessary to include younger population groups; as we have seen in the present study we have observed an audiometric profile similar to that of presbycusis may appear at a young age.
Many other studies attempt to establish the prevalence of presbycusis in different populations. To avoid repetition, we refer to the review carried out by Roth et al.,7 which included 19+7 studies. In most of these studies there are many biases, both in the selection of patients and inclusion criteria, and in the population groups considered.
Many of these studies present a substantial amount of asymmetric hearing loss, and the worst ear was used to calculate the prevalence of ARHL. Presbycusis is considered a bilaterally symmetric sensorineural hearing loss. Therefore, following the inclusion criteria in this study, if there is an asymmetry in the hearing, it cannot be considered as ARHL. Moreover, if the hearing loss is not sensorineural, it cannot be considered as ARHL either.
Sex does not seem to be a significant factor in the present study and other like Quaranta et al.9 However, most studies find differences in hearing threshold between men and women. This may be because they have considered an unscreened population. As Homans et al.25 explains, a clear difference at 4kHz is found, and this may be due to an occupational or recreational noise exposure.
The use of a screened population could justify that we have not found subjects with severe or profound hearing impairment as well.
We found a slight hearing loss in the younger age group (5–14 years) according to the ASHA classification. This could be attributed to an environmental exposure (sociacusis) such as personal music player use as proposed by Le Prell et al.26 Some studies indicate that hearing thresholds improve from infancy up to the age of 8–12 years old.27 Other authors attribute this effect either to possible problems of concentration, to earphone fitting problems, to general developmental changes, or to difference in the length and volume of the ear canal (the influence of ear canal resonance).28,29
Most studies measuring prevalence of ARHL were made in the northern and western of Europe,7 and two studies in southern Europe.8,9 Although no geographic-related pattern can be derived from Roth et al.7 study, we contributed our epidemiological data for this geographic area (Mediterranean/southern Europe).
ConclusionsThe prevalence of presbycusis increases with age. Mild hearing loss may be detected over 60 years old, moderate hearing loss over 72 years old, and all subjects older than 80 years have presbycusis; although the results vary depending on the classification system used. Therefore a common classification system should be used.
An otologically normal (screened) population is needed to establish the prevalence of presbycusis as the hearing level including all types of hearing loss is measured in non-screened populations, but not presbycusis itself.
Ethical approvalAll procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments.
Financial disclosureThere are no financial conflicts of interest to disclose.
Conflict of interestAuthors declare that they have no conflict of interest.
Informed consentInformed consent was obtained from all individual participants included in the study.
