Normative Hearing Threshold Levels in Koreans with Normal Tympanic Membranes and Estimated Prevalence of Hearing Loss

Abstract

Objectives We investigated the normative data on the hearing threshold levels of Koreans with normal tympanic membranes and the prevalence of hearing loss (HL) and nonserviceable hearing using the data from the Korea National Health and Nutrition Examination Surveys (KNHANES) during 2010–2012.Methods Data obtained from 16,673 participants ≥12-year-of-age with normal tympanic membranes who completed audiometric testing. We defined HL as the pure tone average (PTA) >25 dB hearing level at 500, 1,000, 2,000, and 3,000 Hz and non-serviceable hearing as PTA >40 dB hearing level.Results The hearing levels at some frequencies (0.5, 3, and 6 kHz) did not differ in between the 10’s and 20’s, but the hearing thresholds at all frequencies increased gradually from the 30’s. The hearing thresholds were higher in men than in women at high frequencies (3, 4, and 6 kHz) in the 30’s and older. The prevalence of HL in either ear was 16.5% (estimates of 5.9 million), from 2.4% in the 10’s up to 75.4% in the 70’s and older. The prevalence of nonserviceable hearing in either ear was 6.8% (estimates of 2.5 million) and that of bilateral nonserviceable hearing was 2.5% (estimates of 0.9 million).Conclusion Hearing loss aggravated from the 30’s at all frequencies and men showed poorer hearing levels than women at high frequencies. Hearing loss was a common condition and the prevalence of non-serviceable hearing in either ear, which needs hearing rehabilitation to help social communication, was 6.8%. Normative pure tone thresholds at each frequency can be used as referent values when counseling patients complaining of hearing loss.

Longitudinal Pure‐Tone Threshold Changes in the Same Subjects: Analysis of Factors Affecting Hearing

“…Numerous studies investigating a pathophysiology and treatment for HL are being published and reported with increasing prevalence of HL. However, many of the studies had limitations to estimate the degree of HL for a certain period or to determine what characteristics affected hearing . It is meaningful that this study was designed with a longitudinal scheme, and the data was obtained from general population.…”

“…The increase of patients with HL is widely thought to result from the increase of an older population due to the extension of an individual's lifespan. A recent study using the Korean National Health and Nutrition Examination Survey from 2010 to 2012 suggested that the prevalence of HL in the 60s and 70s age groups was 49% and 75%, respectively . However, the prevalence of patients with HL has increased even in the relatively younger generation, especially in the 40s age group (Table ).…”

“…However, many of the studies had limitations to estimate the degree of HL for a certain period or to determine what characteristics affected hearing. [1][2][3] It is meaningful that this study was designed with a longitudinal scheme, and the data was obtained from general population.…”

“…A study with cross‐sectional design is advisable when determining the prevalence of this impairment. Although cross‐sectional studies have been performed in past decades, they had some limitations. In a cross‐sectional study, the measurement of degree of pure‐tone threshold changes for a certain period was infeasible, thus it was difficult to identify risk factors associated with the threshold changes.…”

Pure Tone Audiometry Threshold Changes for 10 Years in the Same Individuals of General Population: A Retrospective Cohort Study

“…Cross-sectional studies on ARHL have been conducted in Korea; however, these studies had a tangible limitation in that it was infeasible to identify changes in hearing ability in a single individual over a specific period. 3,4 To overcome this limitation, qualified longitudinal studies were conducted. Nevertheless, those investigations also had shortcomings; (1) some were performed only on subjects in particular occupations 9-12 ; (2) subjects’ hearing levels were assessed by self-reporting, not PTA 12 ; (3) some focused on risk factors other than aging, such as smoking, central adiposity, and poorly controlled DM in the Beaver Dam Eye Study 8 ; and (4) most studies were published quite a long time ago and did not reflect changes in people’s environment and lifestyle, for instance, the decrease of occupational noise exposure and the increase of vulnerability to other sound sources including music concerts, film theaters, and portable audio devices.…”