STRENGTHS AND LIMITATIONS OF THIS STUDY

Given that the studied sample is from an under-researched population and is of an adequate size, the findings are pertinent to the growing literature on extended high-frequency hearing.

The audiometry testing and questionnaires applied to the population were performed by experts in the audiology and otology fields, and the application of these instruments was standardised.

The cross-sectional design of this study can prove association but not causality between the variables.

There is heterogeneity in the literature about the definition of a standardised threshold of normal hearing in young populations which may have affected the interpretation of this study.

Introduction

Hearing loss in younger populations can lead to reduced physical health, quality of life and academic performance.1 The WHO has stated that up to 60% of childhood hearing loss can be attributed to preventable causes.2 A meta-analysis reported a prevalence of hearing loss due to social noise exposure in standard frequencies (0.25–8 kHz) ranging from 11.5% to 15.8% in adolescents aged 10–19 years.3 Evidence has displayed disparities between low-income and high-income communities with regards to the prevalence, early diagnosis and treatment of hearing loss.4 5 McDaid et al estimated a global economic cost of hearing loss that exceeded US$981 billion, with up to 57% of this burden falling on low-income and middle-income countries. Moreover, 6.5% of these costs were attributed to children aged 0–14 years.6 Social determinants associated with hearing loss among school-age children and adolescents include low socioeconomic level, household income, education level and low maternal education level.7 Health interventions for the prevention, diagnosis and early treatment of hearing loss in young populations are cost-effective compared with the substantial long-term costs related to quality of life deterioration, poor school performance and disability-adjusted life years.8 Furthermore, early treatment of hearing loss significantly improves the aural rehabilitation process and quality of life in these populations.8

The gold standard test for diagnosis of hearing loss is conventional pure-tone audiometry which assesses hearing sensitivity at the standard frequencies of 0.25–8 kHz; these frequencies are essential for communication and speech intelligibility.9 Extended high frequency audiometry (EHFA) assesses hearing thresholds at frequencies between 9 kHz and 20 kHz.10 Prior studies report that EHFA may allow the detection of hearing loss due to middle ear diseases and ototoxicity.11 12 Additional risk factors for high-frequency hearing loss include ageing,13 obesity,14 environment15 and recreational noise exposure (ie, headphones, personal devices).16 Moreover, several studies suggest that EHFA allows the detection of subclinical hearing loss prior to speech frequencies deterioration.11 17 18 Extended high frequency (EHF) hearing may be particularly important in young populations for the development and acquisition of speech and language.19 20 Therefore, current evidence emphasises that conventional audiometry should be complemented by EHFA in childhood.10 21

In Colombia, a study among adolescent rural populations described prevalence of hearing loss of 3.83% assessed through conventional pure-tone audiometry, and of 14.21% assessed through EHFA.4 However, the factors associated with hearing loss in this study did not allow a distinction between the factors associated with conventional pure-tone hearing loss and EHF hearing loss. Therefore, studies focusing on the factors associated with EHF hearing loss in young rural populations are needed. Moreover, the study concluded that hearing loss is already widespread in young rural populations and the authors hypothesised that factors associated with hearing loss could be affected by clinical, environmental and cultural differences. For instance, environmental conditions and some cultural activities may increase or reduce noise exposure in young populations leading to a higher risk of developing hearing loss.4 Studies that provide evidence in different cultural backgrounds and test this hypothesis are needed. To date, research on hearing loss within young rural populations is scarce and has methodological discrepancies such as heterogeneity in hearing normalcy parameters, and differences in the EHF hearing thresholds depending on the audiometry equipment.22 23

Isla Barú is a low-income Afro-descendant community with 8177 inhabitants located on the Colombian north coast and most of its population lives in small rural settlements with inadequate hygiene services, no sewage system infrastructure, no access to drinking water and only one healthcare centre for the entire population.24 25 Similar barriers to healthcare access have been previously described in rural populations from high-income countries, and these disparities have hindered the implementation of hearing screening programmes.26 This study focused on a low-income Afro-descendant population of Colombia, a low-income/middle-income country with healthcare system inequalities related to the socioeconomic and geographical characteristics of the population.27 To date, there are no hearing screening programmes available for any rural population in Colombia, and implementing an initial audiology diagnostic approach for the Isla Barú population would provide crucial information about their current hearing health. In addition, current research emphasises the importance of representing different ethnic populations in science.28 29 The main aim of this study was to determine the prevalence of acquired hearing loss through conventional pure-tone audiometry and EHFA testing within an adolescent population (aged 13–17 years) in Barú (Colombia) in 2021. As a secondary aim, we also assessed the main sociodemographic and clinical factors associated with EHF hearing loss.

MethodsStudy design

This was an observational, cross-sectional, analytical study conducted during February-March 2021 in which conventional pure-tone audiometry (0.25–8 kHz) and EHFA (9–20 kHz) were performed in Afro-Colombian adolescents aged 13–17 years from Isla Barú, Colombia. Sociodemographic and risk factor questionnaires were applied to assess probable factors associated with acquired EHF hearing loss. Informed assent was obtained from all the participants and informed consent was obtained from their parents.

Participants

The sample was selected through random probabilistic sampling from a list of all pupils attending the ‘Institución Educativa Santa Ana’ who fulfilled the inclusion criteria of the study; this list was provided by the high school administration. This school is one of three high school institutions in Santa Ana, Isla de Barú, and the only institution with high school grades certified by the Colombian Ministry of National Education.24 There is no information in the municipality reports about the percentage of adolescents that attend high school education in Isla Barú.24 As suggested by Kim and Shin,30 randomisation was performed by assigning a number to each student and using the Excel function to randomise a sample without stratification. The sample size was determined as follows: (1) The high school administration reported a population of 291 schoolchildren 13–17 years old; (2) A prior study that estimated a prevalence of 26.1% of mild hearing loss,31 and (3) The following formula:32 33

where d was the error of estimation and p was the prevalence. This formula was adjusted adding an expected loss rate of 5% (due to non-response and/or incomplete data). A minimum sample size of 189 adolescents was planned. The inclusion criteria were: (1) Adolescents aged 13–17 years, (2) Who attended the ‘Institución Educativa Santa Ana’ high school in Isla Barú in February-March 2021, (3) Who have signed the assent with the school psychologist and had their parents’ consent to participate in the study. While the planned minimum sample size was based on the population size provided by the school administration, new students enrolled in the school during the fieldwork of this research. As the researchers were providing a first-time otological care approach to an underserved population, the recruitment continued despite reaching the planned sample size. After meeting the target sample size, a consecutive sampling without replacement, using a negative coordination method, was conducted by recruiting newly enrolled students to achieve a uniform, independent sample selection.34

Adolescents who reported a prior history of cognitive impairment, head trauma, congenital sensorineural hearing loss, middle ear disease (such as chronic otitis media), or any chronic comorbidity that would limit their ability to participate were excluded from the study. Middle ear diseases were excluded due to the potential ear discharge, which is considered a contraindication for audiometry testing.35 36 These clinical conditions were initially identified through either parental or participant self-report. However, since our intervention was the first audiology and otology diagnostic approach for most of the adolescents, any exclusion criterion identified during the clinical assessments resulted in the exclusion of the adolescent’s data from the analysis. Adolescents were excluded from the study if the otologist diagnosed conditions such as: impacted earwax that could not be removed, dermatological diseases of the ear canal; otitis externa; keratosis obturans; prior radiation therapy affecting the ear; obstructive exostoses, neoplasms of the ear canal; previous tympanoplasty/myringoplasty, canal wall down mastoidectomy, or any prior surgery affecting the ear canal.37 Moreover, those adolescents who declined to participate or did not attend the informed assent session were also excluded. Before obtaining informed assent, a cognitive level assessment was conducted by the school psychologist for each potential participant using the Mini-Mental State Examination Standardised Questionnaire.38 If the Mini-Mental State Examination Standardised Questionnaire results indicated cognitive impairment that would limit their ability to solve the questionnaires, the participants were excluded from the study.

Otoscopic assessment

The otoscopic examination was performed using a Welch-Allyn otoscope by a medical doctor and an otologist before the audiological testing to identify contraindications to testing, such as impacted earwax, and guarantee a free passage to the eardrum. We followed the American Academy of Otolaryngology-Head and Neck Surgery recommendations for earwax management.37 Considering the importance of watchful follow-up and surveillance in these contexts, the parents were guided to schedule a follow-up appointment with their otolaryngologist through their health insurance plan. Additionally, we educated the adolescents on proper ear hygiene to help prevent impacted earwax.

The main otoscopic findings were classified by the otologist into six previously established categories as follows:39 normal tympanic membrane, perforated eardrum with discharge, inactive squamous epithelium (retraction, atelectasis, epidermolysis), dry perforated eardrum, squamous epithelium (cholesteatoma), and healed chronic otitis media (neotympanum, intact tympanic membrane, tympanosclerosis).

Audiometry testing

Audiometry was conducted using international standardised protocols (ISO:8253–1) to measure the quietest intensity in decibels hearing level (dB HL) at which a tone could be heard by the individuals at a specific frequency.40 41 Air and bone conduction thresholds were measured using an R37a (resonance) diagnostic audiometer that was calibrated following the American National Standards Institute (ANSI) 3.6 guidelines, 2018 edition.42 The audiometry tests were performed in a double-walled soundproof booth (Amplivox) following the criteria of maximum permissible ambient noise levels for audiometry test rooms (ANSI/ASA (Acoustical Society of America) S3.1–1999 (R2013) standard guidelines).42 The audiologists used Radioear DD-45 supra-aural headphones to assess the hearing at conventional frequencies, Sennheiser HDA (High Definition Audio) 300 circumaural headphones for the EHFA range and a B71W transducer to assess bone conduction. A professional audiologist with wide clinical experience performed the audiometry testing. The audiometric frequencies assessed in the test were conventional frequencies (0.25 kHz, 0.5 kHz, 1 kHz, 2 kHz, 3 kHz, 4 kHz, 6 kHz, 8 kHz) and EHFs (9 kHz, 10 kHz, 11 kHz, 12 kHz, 14 kHz, 16 kHz, 18 kHz, 20 kHz). Tympanometry was not performed in the study due to budget limitations.

Sociodemographic and clinical questionnaires

Sociodemographic and clinical written questionnaires were applied by trained medical doctors and researchers to the adolescents, under the supervision of their parents or legal tutors, and the completion time of these questionnaires was controlled. The sociodemographic questionnaire included questions about age, number of people living in the household and number of rooms in the home. The clinical questionnaire was designed by the authors based on previously reported risk factors for hearing loss.4 10 43–45 The clinical questionnaire included questions about childbirth mode (caesarean vs vaginal delivery); breast feeding in infancy (yes/no); moderate alcohol consumption (defined as more than two times a week: consumption of two drinks per day of one beer (350 mL, 4.5% alcohol) or one glass of wine (148 mL, 12%–16% alcohol) or more than two shots of Colombian schnapps (90 mL, 30% alcohol));46 cigarette smoking (more than 1–5 days per month);43 high volume use of recreational headphones or personal devices for more than 2 hours per day;44 duration of recreational headphones or personal devices in hours;44 number of times attending ‘picó’ (a social gathering event that exceeds 120 dB (A)); number of times attending a bar/pub/disco in the last month; exposure to loud environmental noises at home (traffic, building constructions near home); number of hours of exposure to high volumes of noise;45 prior self-reported hearing difficulties or hearing loss; previous hearing loss-related noises: ringing, whistling, clicking, roaring (tinnitus);47 constantly telling people to repeat messages or to speak louder to understand what they say; concentration difficulties due to noise.48 Finally, height and weight were directly measured by the medical doctors following clinical guidelines to ensure the accuracy and reliability of childhood growth measurement equipment and using previously calibrated weights and rods.49

Statistical analysis

Statistical analysis was performed using Stata V.16MP software. For qualitative variables, absolute and relative frequencies were calculated. For quantitative variables, measures of central tendency (mean, median) and dispersion (SD or IQR) were assessed. Body mass index was classified considering the international categories established by WHO.50 The Household Crowding Index was calculated based on the WHO Housing and Health guidelines as the total number of people in the household divided by the total number of rooms (excluding kitchen and bathrooms).51 The normal hearing threshold for air conduction in children and adolescents is expected to be at or below 15 dB.21 Therefore, we applied this parameter to the pure-tone average (PTA) across either the conventional frequencies (0.25 kHz, 0.5 kHz, 1 kHz, 2 kHz, 3 kHz, 4 kHz, 6 kHz, 8 kHz) or EHFs (9 kHz, 10 kHz, 11 kHz, 12 kHz, 14 kHz, 16 kHz, 18 kHz, 20 kHz) range, to determine the prevalence of hearing loss in this population. As previously stated, congenital hearing loss and middle ear diseases were excluded from the analyses.

The prevalence of hearing loss through conventional frequency and EHF audiometry was calculated along with its CI based on sampling weights of a random sampling process. A Fisher’s test or χ2 test was conducted to determine associations between qualitative variables. The Student’s t-test or Mann-Whitney test were also performed to evaluate the associations between quantitative and qualitative variables according to data distribution. The measures used to address the study aims for conventional audiometry and EHFA included mean hearing thresholds and SD. Median hearing thresholds (p50) and IQR (P25–P75) for air conduction were also calculated for each participant’s ear.

Furthermore, a robust cluster logistic regression analysis was conducted to determine the adjusted effects of the variables associated with EHF hearing loss. Bivariate and multivariate analyses were employed to assess the associations (prevalence ratios: PRs) between the factors associated with EHF hearing loss. These variables were selected based on biological plausibility and prior research findings regarding hearing loss.4 7 10 The model assumptions were validated through a linearity test, the Pearson test, an estimation of deviance residuals, Cook’s values, and a comparison between the crude and the adjusted models. The criterion for statistical significance was set at p<0.05.

Patient and public involvement

The school principal and teachers were involved in setting the fieldwork methodology, the design and the implementation of the study. Moreover, with the support of community alumni and teachers from the high school, the researchers organised a meeting with the parents of the school students. The researchers made a commitment to the community to provide otolaryngology care for students who did not meet the inclusion criteria but presented with conditions that required medical assessment. If hearing loss was identified in any participant, their parents were informed and educated about the importance of therapeutic intervention and the need to follow-up with an otolaryngologist in the nearest urban city, Cartagena. The follow-up of these students was also supported by the school’s psychologist. The researchers performed an additional visit to the community 6 months after the fieldwork to share the anonymised findings with the participants during a meeting with the school principal and staff. We shared the anonymised findings with the school principal, the participants in the study, their families, and the community. An education campaign on hearing care and hearing loss prevention was also performed in the community, and informative hearing care flyers were designed and provided to teachers, parents and the community (online supplemental file 1).

Results

A total of 237 adolescents were invited to participate in the study: the first 189 were recruited via random sampling and the remaining 48 were newly enrolled students who were recruited consecutively. Of the 237 adolescents invited, 6 (2.52%) were excluded due to meeting the exclusion criteria: 1 congenital hearing loss (0.42%), 1 cognitive impairment (0.42%), 4 middle ear diseases (1.22%). Of the remaining 231 adolescents, 1 declined to take part in the study (0.42%). Therefore, 230 adolescents were included in the study analysis (response rate 99.57%), of which 133 (57.83%) were female. The mean age was 15.22 years (SD=1.66). Table 1 describes the sociodemographic characteristics of the population.

Table 1

Sociodemographic characteristics

Half of the adolescents reported using headphones or personal devices for more than 2 hours per day, and 42.6% of the sample reported being exposed to high volume for more than 2 hours per day. Up to 86.52% reported engaging in noisy social gathering activities two or more times per month (ie, ‘picó’ exceeds 120 dB (A)). Moreover, 93.04% of participants reported visiting bars/pubs/discos at least twice a month, and 51.30% reported being exposed to noisy environments within their homes. Table 2 describes the hearing habits, otoscopic findings and air conduction PTA in the sample.

Table 2

Hearing habits and clinical characteristics of the study population

Prevalence of hearing loss

An average hearing threshold of ≤15 dB was considered as normal hearing parameter for the analysis. Average hearing thresholds per ear and frequency are shown in table 3. All thresholds could be measured at every frequency in both ears (n=230). The frequency of acquired hearing loss in the right ear assessed through conventional audiometry was 20%, and through EHFA was 16.09%. Likewise, the frequency of acquired hearing loss in the left ear assessed through pure-tone audiometry was 15.65% and assessed through EHF 18.70%. Overall, the prevalence of acquired hearing loss in at least one ear assessed with pure-tone audiometry was 21.3% (95% CI 16.45% to 27.17%) and through EHFA was 14.78% (95% CI 16.45% to 27.17%).

Table 3

Conventional frequency and EHF air conduction audiometry results categorised by ear

Finally, about acquired EHF hearing loss in different frequency ranges, the prevalence of EHF hearing loss was distributed as follows:

9–14 kHz hearing loss (PTA >15 dB): right ear 9.57% (n=22), left ear 10.87% (n=25), bilateral 3.48% (n=8).

16–20 kHz hearing loss (PTA >15 dB): right ear 10.87% (n=25), left ear 8.26% (n=19), bilateral 5.22% (n=12).

Figure 1 shows the density curves (distribution) of the median hearing thresholds (dB HL) of the participants with presumed acquired hearing loss (excluding middle ear diseases) for both, conventional pure-tone audiometry and EHFA combined for both ears. The wider sections of the violin plot indicate higher density of data points at those values, providing information about the distribution and concentration of data across different value ranges. This suggests that more observations are clustered around these values. Although the mean remains under the normal hearing threshold parameter (ie, ≤15 dB HL), some atypical data exceeded that threshold. Regarding EHF in the right ear, some results can be classified as moderate hearing loss, while for the left ear some data can be classified as severe hearing loss.

Figure 1

Violin plot that shows the density curves of the median pure-tone audiometry and EHFA results of adolescents with hearing loss for both ears combined. The wider sections of the violin plot indicate higher density of data points at those values, providing information about the distribution and concentration of data across different value ranges. This suggests that more observations are clustered around these values. EHFA, extended high frequency audiometry.

Factors associated with acquired EHF hearing loss

Table 4 describes the model to assess the factors associated with hearing loss in the population. A total of 460 ears were included in the association model. The main factors associated with EHF hearing loss in the reduced model included: older age (PR: 1.45; 95% CI 1.16 to 1.80), attending the ‘Picó’ four or more times a month (PR: 6.63; 95% CI 2.16 to 20.30), attending bars more than three times a month (PR: 1.14; 95% CI 1.03 to 1.59), and self-reported hearing difficulties (PR: 1.24; 95% CI 1.22 to 4.05). No collinearity problems were found in the reduced model using the linearity and the goodness-of-fit tests. The goodness of fit of the Pearson test showed good model specifications (p=0.97). A total of 22 influential values were found for the residuals and leverage values. When comparing logistic regression with and without these values, no important changes were observed in the coefficient estimation in terms of the direction of the association, hence, these values were not removed from the analysis. Finally, the relationship between age, sex and EHF hearing loss is illustrated in online supplemental file 2.

Table 4

Robust logistic regression model of the factors associated with acquired EHF hearing loss (excluding middle ear diseases)

Discussion

This study aimed to determine the prevalence of acquired hearing loss through conventional pure-tone audiometry (0.25–8 kHz) and EHFA (9–20 kHz) among adolescents aged 13–17 years from a deprived and rural Afro-descendent area in Colombia. The prevalence of acquired hearing loss in the sample in at least one ear, as assessed with conventional pure-tone audiometry, was 21.3%, and with EHFA was 14.78%. Likewise, a study in the USA of children aged 4–19 years with clinically normal hearing reported that EHF hearing impairment is common and can occur without a history of otitis media.52 A prior study in low-income rural Colombian adolescent populations described a prevalence of hearing loss with pure-tone audiometry of 3.56% and with EHFA of 10.14%.4 Despite the similarity in methodology and the inclusion of low-income rural adolescents in both studies, a higher prevalence of both conventional and EHF hearing loss was observed in Barú. These differences could be attributed to noise exposure and the frequent engagement in noisy social gathering activities, which hold cultural relevance in these populations, such as picó. However, further studies are needed to test this hypothesis. Other authors have suggested that rural populations may have lower exposure to environmental noise,53 and healthy young populations are assumed to have the most sensitive hearing compared with other age groups.54 However, our findings suggest that hearing loss is frequent in this young rural population. We emphasise that half of the adolescents reported using headphones for more than 2 hours per day, and 42.17% used these headphones at high volumes for recreational purposes. Furthermore, up to 51.30% also reported being exposed to noisy environments in their homes. This scenario, along with the frequent exposure to loud (≥120 dB (A)) social gathering activities exceeding the maximum recommended daily dose of noise exposure (85 dB for 8 hours per day), may be comparable to noise exposure in urban populations.16 Overall, noise exposure in this population may lead to an increased risk of hearing loss, which may be mirrored in the high prevalence of hearing loss reported in this study.

Prior studies have stated that higher frequencies are lost before speech frequencies.55 56 Moreover, a current study in a paediatric population from the USA described that EHF impairment can be associated with poorer speech-in-noise recognition and preclinical cochlear deficits in the lower frequencies where hearing thresholds are normal.52 However, these clinical findings need further studies as in our study population, a higher prevalence of hearing loss in conventional pure-tone frequencies was found compared with EHF (see figure 1). We highlight that environmental noise during testing met international standard requirements (ISO:8253–1).41 Thus, these findings are unlikely to be related to technical issues. A total of 41.8% of participants with hearing impairment exclusively in the conventional frequencies (ie, no EHF involvement) had a sloping audiometric configuration; 36.6% had a U-shaped audiogram at 4–6 kHz; 8.2% had a flat configuration; and 4.4% had a tent-shaped configuration; and 9% had other types of audiogram configurations (ie, rising). However, since tympanometry was not performed, some conductive pathologies may have been undiagnosed, and this variable may also explain these findings. These findings could be also explained by population variations or differences in noise exposure frequencies (ie, ‘picó’ during long periods). Early exposure since childhood to this risk factor could lead to a rapid deterioration of speech frequencies. The intensity of the acoustic signal and the length of exposure are essential for assessing the probability of developing hearing loss.4 However, these findings were not specifically documented, and we were not able to determine this variable in the study. Thus, additional research studies to assess these findings are needed.

Regarding the factors associated with acquired EHF hearing loss in this study population, the probability of having this condition was higher in older adolescents (PR: 1.45; 95% CI 1.16 to 1.80). This finding is similar to that of a prior study in a Colombian adolescent population that found that older age increased the risk for hearing loss (OR: 1.36; 95% CI 1.13 to 1.64).4 This association between ageing and hearing loss has been previously attributed to multiple factors: genetic predisposition, physiological stressors (ie, metabolic diseases), environmental noise exposure and modifiable lifestyle behaviours.57 58 Moreover, this finding has biological plausibility, since prior literature has stated that ageing leads to EHF deterioration.54 59 60 Additional factors that increased the probability of EHF hearing loss in this study population were attending ‘Picó’ four or more times per month (PR: 6.63; 95% CI 2.16 to 20.30) and attending bars more than three times per month (PR: 1.14; 95% CI 1.03 to 1.59). These findings are supported by prior studies suggesting that loud recreational noise can potentially impact higher frequencies.61 However, the evidence for these associations remains contradictory, and further studies are needed.20 62 Additionally, a large CI was found for the association between EHF HL and attending ‘Picó’ at least four times a month, which may be related to the small sample size (4.35%) of the population that practised this cultural habit. Finally, another factor that increased the probability of EHF hearing loss in this study population was self-reported hearing difficulties (PR: 1.24; 95% CI 1.22 to 4.05). This factor has been previously described as a risk factor for hearing loss in paediatric and adult populations,63 64 which supports the use of questionnaires as cost-effective screening tools.

Finally, we highlight that no associations were found between acquired EHF hearing loss and high-volume recreational headphone use for more than 2 hours/day or environmental noise exposure. This scenario may be attributed to the approach of exposure length used in the questionnaire, which only captured noise exposure habits within the previous month. Prior literature states that hearing thresholds in EHF might be affected by noise exposure from earlier periods,55 56 which may imply that EHFA can be useful to identify individuals with subclinical hearing loss not apparent in conventional audiometry. However, a study that explored leisure noise exposure and EHF hearing threshold shift displayed contradictory findings.62

Overall, this study supports that hearing loss among this young rural population is already widespread, which highlights the need for hearing health intervention policies for rural and low-income populations. According to prior literature, health education strategies should focus on factors that may trigger hearing loss, hearing protection, audiometry testing and noise regulations.55 Previous hearing health policies and educational campaigns in high-income countries have shown high efficacy rates in reducing these risk behaviours related to hearing loss.65 66 However, there is a shortage of resources to prevent and treat hearing loss in low-income and middle-income countries,67 and these strategies should be adapted to reach low-income populations. Rural populations may be vulnerable to hearing loss, and research is needed to address the barriers to hearing care and expand access for these populations.

Among the strengths of this study, we highlight that the studied sample is from an under-researched population and is of an adequate size. Therefore, the findings are pertinent to the growing literature on EHF hearing. No significant differences are expected between the population that attended the educational institution included in the study and the remainder adolescent population in the municipality of Barú. Moreover, data collection was performed by trained medical doctors and researchers, and the completion time of the questionnaires was controlled. The questionnaires applied to the population were designed by experts in the audiology and otology fields, and the application of these instruments was standardised.

Finally, regarding the limitations of the study, we highlight its cross-sectional design since it cannot prove causality between the variables.68 The heterogeneity in the definition of a normal hearing parameter in young populations is also a limitation that may have affected the interpretation of this study:4 some authors recommend using thresholds of 25 dB as ‘normal hearing parameter’,69 others suggest using 20 dB,70 and a prior study recommended using 15 dB.21 Standardised thresholds that allow homogeneous comparisons in terms of hearing loss in young populations are needed. Moreover, we highlight that further studies comparing the prevalence of EHF hearing loss in rural and urban populations are needed to assess the benefit of EHF audiometry in the screening process (early identification of hearing loss).

Conclusions

Using 15 dB as the normal hearing threshold parameter to assess the prevalence of hearing loss, a prevalence of 21.30% was found using conventional pure-tone audiometry and 14.78% using EHFA. Among the young, low-income, rural study population, the factors associated with a higher probability of acquired EHF hearing loss were older age (PR: 1.45; 95% CI 1.16 to 1.80), attending ‘Picó’ four or more times a month (PR: 6.63; 95% CI 2.16 to 20.30), attending bars more than three times a month (PR: 1.14; 95% CI 1.03 to 1.59) and self-reported hearing difficulties (PR: 1.24; 95% CI 1.22 to 4.05). Considering the limited access to healthcare in these populations, further research is needed to address the barriers to hearing care.

Data availability statement

Data are available upon reasonable request. Most of the data generated or analysed during this study are included in this published article. Full anonymised data set and code can be shared with researchers on request to the corresponding author.

Ethics statementsPatient consent for publication

Consent obtained from parent(s)/guardian(s)

Ethics approval

This study involves human participants. The Ethical Committee of the Fundación Santa Fe de Bogotá (CCEI-11663-2020) and the Universidad de Los Andes (Act No. 1255 of 2020) approved and audited this study according to the Declaration of Helsinki. Participants gave informed consent to participate in the study before taking part.

Acknowledgments

The authors thank Maria José Suetta-Lugo and Dellys Castro for their logistical support in the fieldwork of this study. The authors also thank Augusto César Rodríguez Maturana, the school principal of the Institución Educativa Santa Ana Barú – IESA and all the school teachers and staff that supported this work. The authors also thank the Fundación Amor por Barú for their support in the fieldwork. The authors thank the Vicerrectoría de Investigación y Creación and the School of Medicine of the Universidad de Los Andes, and the Subdirección de Estudios Clínicos y Epidemiología of the Fundación Santa Fe de Bogotá for their funding support to for this manuscript. Part of the findings reported here were presented by LCP-H as oral presentation in the 2022 Pan-American Congress of Otolaryngology-Head and Neck Surgery in Orlando, Florida, USA. A poster of these findings was also presented at the Congress of the American Academy of Otolaryngology-Head and Neck Surgery 2022, and an abstract of this poster will be published in the Journal of the American Academy: Otolaryngology–Head and Neck Surgery.