This study described the average rate of threshold and PTA change per year in a diverse community-based sample of adults across the adult lifespan, overall and stratified by sex, race, and baseline age group. In this sample, the rate of threshold change ranged from 0.42 to 1.44 dB per year, and findings suggest that hearing declines across the entire adult lifespan. Key findings from stratified analyses include: i) average rates of hearing declines differed by sex; these differences were observed across most individual thresholds, but not PTA, ii) Black/African American participants had a lower rate of threshold and PTA change per year as compared to white participants, and iii) in general, hearing declined across the adult lifespan, although older (versus younger) age groups had higher rates of threshold and PTA declines per year.
To compare our results to those from other studies, it is first necessary to highlight important differences in study methodologies and sample compositions, in terms of age, sex, and race, which can influence the comparability of results. The rates of threshold change per year reported in this study (0.42 to 1.44 dB) are similar to results from an earlier study conducted in 188 participants from the same cohort, which reported the rates of change to be 0.7 to 1.2 dB per year across frequencies14. The slight discrepancies in estimates can likely be explained by the present study having a larger sample size with more follow-up time, a wider age range, and more Minority (namely, Black/African American) participants. Studies conducted in other cohorts have also reported rates of threshold change that are generally consistent with findings from this study. For example, a study conducted in males aged 20 to 95 years and with 11 years of follow up reported rates of threshold change as 0.7 to 1.7 dB per year12. Next, a study in younger adults (31 to 50 years) reported the 5-year rates of threshold change as 0 to 2.5 dB across frequencies15, which are similar to the estimates presented for 18- to 40-year-olds in this study if estimated over 5 years. Two studies conducted in 60 to 80+ and <30 to 80+ year old adults reported the rates of threshold change to be 1 to 15 dB in 6 years and 0 to 18 dB in 10 years, respectively12,13. As compared to the present study, those studies reported greater rates of change in the high frequencies. Differences in the rates of high-frequency threshold change may be explained by differences in sample composition, namely that other samples did not include a substantial proportion of Minority participants. In addition to demographic differences in sample composition, there may be cohort differences in exposures to risk factors for hearing loss, such as excessive noise or cardiovascular or metabolic ill-health, which would contribute to differences in estimated rates of change33,34,35,36. There may also be birth cohort (generational) differences across cohorts, which would likely influence rates of hearing decline19. To facilitate comparison of results from this study with those from the previous studies described above, we assessed differences in rate of hearing change by demographic factors, but did not assess other risk factors for hearing loss. This point will be discussed later.
Previous studies have consistently shown hearing loss prevalence and incidence is higher in males1,2,8,9, and that hearing loss onset in men occurs earlier than it does in females9. In this study, there were clear sex differences in rates of threshold change per year, in that females had higher rates of change in the higher frequencies, but men had higher rates of change in some lower frequencies. This is likely because hearing in males has already declined and the thresholds in males are closer to the limits of hearing, particularly for the high frequencies, where hearing loss often presents first37. This is supported by the results showing males have higher baseline thresholds at higher frequencies than females (Table 2) and that this trend exists across all age groups (Supplementary Table 2). In general, this notion is also supported by the results shown in Supplementary Fig. 1. That is, males aged 18 to 39 years at baseline showed significantly (6000 Hz) or non-significantly higher rates of threshold change than females. The pattern where females had higher rates of change in the higher frequencies emerges in the 60- to 69-year baseline age group. Among 60- to 69-year-olds at baseline, females show significantly higher threshold change at 4000 to 8000 Hz, and among 70+ year olds at baseline, females show significantly higher threshold change at 3000 and 4000 Hz, suggesting that changes to hearing among females progress to the lower frequencies as baseline age increases. Studies conducted in other cohorts similarly reported rates of decline are higher for females than males, particularly in the higher frequencies10,13,14. In this study, sex differences were not observed for rate of PTA change. This suggests that using an average, such as PTA, may mask the sex differences in rate of change observed at individual frequencies.
In this study, white participants showed higher rates of threshold change than Black/African American participants across all frequencies and PTA and had higher average baseline thresholds overall and at most frequencies across each group. Results are consistent with research showing Black/African American individuals have better pure-tone thresholds and a lower prevalence of hearing loss23,24,38. To our knowledge, this is the first study to report racial differences in rates of hearing change in a sample of the general population. Our analyses focused on racial differences were limited to white and Black/African American participants given low sample sizes of participants of other races. Previous research indicates there are differences in the prevalence of hearing loss among other racial and ethnic groups, including non-white Hispanic and Asian individuals22,23,24,38,39,40,41. There is a need for future epidemiological hearing research, including how hearing changes over time, to be conducted in diverse samples of the general population.
In general, rates of threshold and PTA change per year were higher in older age groups, which was rather consistent across all thresholds. However, in participants aged 70 years or older, the rates of change in the higher frequencies were lower and were similar to rates of change for participants aged 40 to 59 years. One explanation for this is that, as mentioned above, hearing at the higher frequencies among older people may have already declined and thresholds may be approaching the limits of hearing. This is reflected by the higher baseline thresholds for participants aged 70 or older, particularly at high frequencies (Table 3). Findings from analyses stratified by baseline age group indicate hearing declines across the adult lifespan. Furthermore, findings indicate older individuals experience high rates of threshold decline across the frequency range. These findings are consistent with other cohort studies that have shown older adults experience high rates of hearing declines10,11,12,13,14.
In this study, we present rates of hearing change adjusted for and stratified by demographic factors to understand rates of hearing change in the general population, regardless of the sample’s non-demographic risk factors. Considering only demographic factors is common in studies that describe changes to hearing over time5,8,9,10,11,12,13,14,15, and allows authors to comprehensively describe changes to hearing across demographic subgroups. Importantly, as described above, this study overcomes several critical limitations of previous studies that, for example, were conducted only in men11, in younger or older adults15,17, in individuals without risk factors for hearing loss, such as noise exposure11,12,16, and in samples of primarily white individuals10,11,12,13,15,16. Although there are some limitations to this cohort (discussed below), this is one of the only studies to comprehensively describe changes to hearing in a diverse sample of the general population from across the lifespan.
The goal of this study was to describe the rate of hearing decline across the adult lifespan, rather than to determine the reasons for decline. However, it is important to note that the observed demographic differences in the rate of hearing decline may, in part, capture differences in exposure to risk factors for hearing loss. That is, demographic factors may be surrogate measures for other risk factors for hearing loss. For example, white males are more likely to experience noise exposure than Black/African American males or females of any race42,43,44. Furthermore, there are sex, race, and age differences in other risk factors for hearing loss, including nutrition and metabolic and cardiovascular health45,46,47. Several other longitudinal studies have determined risk factors associated with hearing loss incidence or progression, such as noise exposure, nutrition, and factors related to metabolic and cardiovascular health, and have concluded that ARHL is at least partially preventable5,8,19,48,49. Future research should evaluate associations of modifiable risk factors with the rate of hearing decline. Such research is crucial to informing public health initiatives related to hearing loss prevention.
Data on the rate of hearing change in the general population, such as these, could provide a benchmark for the rate of hearing change that occurs in the general population. These data also have implications towards screening for ARHL in the general population. A recent report from the US Preventive Services Task Force concluded there was insufficient evidence to support screening for ARHL in asymptomatic adults aged 50 years and older50. However, some guidance related to screening for ARHL suggests that screening could begin at age 50 or age 65 years51,52. In the current study, the mean baseline PTAs of participants aged 40–59 and 60–69 years were 18 dB HL and 24 dB HL, respectively. Among participants aged 50–59 years (results not shown), the mean baseline PTA was 18 dB HL. Therefore, results from this study are consistent with guidance that screening for ARHL could begin at 50 years of age to detect early cases of hearing loss, and that screening at 65 years of age could detect more severe cases of hearing loss. Importantly, definitions of hearing loss vary across sources51,52, and there is ongoing discussion on how hearing loss should be defined53. Future research is needed to determine the appropriate age to begin screening using the definitions of hearing loss designated by the agencies recommending screening.
Strengths of this community-based cohort study spanning 35 years include its large and diverse sample and comprehensive measures of hearing, and its longitudinal design. This cohort study is similar to other epidemiological studies of ARHL in terms of age and audiometric hearing loss, which may enhance generalizability of study findings2,25,54. However, some limitations exist. Most participants in this study were white or Black/African American, so differences in the rate of hearing changes by other races could not be evaluated. Research suggests there are differences in the prevalence of hearing loss by race and ethnicity, which this study could not evaluate22,23,24,38,39,40,41. While this community-based sample is conducted in individuals from the general population, results may not be generalizable to the entire population, as participants reside in one geographic region and have relatively high socioeconomic position. It was not possible to evaluate sex- and race-specific rates of change by age group given sample size limitations.
This descriptive study conducted in a diverse, community-based sample of the general population from across the adult age range suggests that declines to hearing occur across the adult lifespan, and that the rate of decline varies by sex, race, and baseline age group. To the authors’ knowledge, this is the first study to document the rate of hearing change per year is lower in Black/African American individuals. Findings from this study highlight the need to prioritize the prevention and/or management of hearing loss in individuals across the adult lifespan and can provide a benchmark for comparing individual or population-level declines to hearing.
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