Trends in Hearing · 1 author, 1 centre
This summary was generated by AI from a single paper. It has not been reviewed by a clinician and is not clinical advice. Verify against the source before acting on it.
This study provides updated hearing threshold norms for U.S. adults using NHANES data from 2011–2012, 2015–2016, and 2017–2020. Compared to the current ISO 1999 standard, median thresholds were slightly better (2–8 dB) at several frequencies, especially for older males. These findings support updating ISO 1999 Annex B to reflect more recent population hearing levels.
**Background** Hearing loss is a common condition affecting U.S. adults, and accurate population-based hearing threshold norms are essential for clinical assessment, research, and public policy. Prior U.S. norms were derived from NHANES 1999–2006 data and incorporated into ISO 1999 (2013) Annex B. However, more recent data suggest that hearing thresholds may have improved over time. This study analyzes the most recent NHANES audiometric data (2011–2012, 2015–2016, and 2017–2020) to provide updated hearing threshold levels (HTLs) for unscreened U.S. adults aged 20 years and older.
**Methods** Data were obtained from three NHANES cycles: 2011–2012, 2015–2016, and 2017–2020 (the latter combining 2017–2018 and partial 2019–2020 data). The total sample included 35,287 participants across all cycles, of whom 11,504 had complete audiograms and 8,795 were adults aged 20 years or older. Audiometric testing was conducted in mobile examination centers using standardized protocols with pulsed-tone stimuli at frequencies 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz. The “better ear” was defined on a frequency-by-frequency basis (PTminLR). Population-weighted median HTLs and percentiles (10th, 25th, 50th, 75th, 90th) were calculated using SAS 9.4 with appropriate survey weights and design variables. Cubic polynomial equations were fitted to median HTLs as a function of age for each sex and frequency.
**Key Results** Median HTLs increased with age and were consistently worse for males than females. For example, at 4000 Hz, median HTLs for males aged 20–29 years were 4.2 dB HL, rising to 35.8 dB HL at age 60–69 and 50.9 dB HL at age 70–79. For females, corresponding values were 1.8, 18.9, and 35.3 dB HL. Compared to ISO 1999 (2013) Table B.3, the current NHANES medians were generally better (lower) by 2–5 dB at 500 Hz for both sexes and by 2–8 dB at 4000 and 6000 Hz for males. Differences were largest for older age groups (e.g., at 4000 Hz for males aged 65–74 years, the ISO value was 9.8 dB worse). Cubic polynomial fits had r² > 0.97 for all sex-frequency combinations. Race/ethnicity effects were also observed: Non-Hispanic Black adults had better (lower) HTLs than Non-Hispanic White adults, especially at higher frequencies and older ages.
**Clinical Implications** These updated norms provide more accurate reference values for interpreting individual audiograms in U.S. adults. The cubic polynomial equations allow estimation of median HTLs for any age between 25 and 85 years. The data support revising ISO 1999 Annex B to reflect contemporary hearing levels. Clinicians should be aware that current ISO norms may overestimate hearing loss by 2–8 dB in certain subgroups, particularly older males. The inclusion of race/ethnicity-specific differences underscores the need for demographic considerations in hearing assessment.