Incidence of presbycusis of Korean populations in Seoul, Kyunggi and Kangwon provinces

Immunoinflammatory and vascular inflammatory factors can be potential disease biomarkers of age-related hearing loss

Objectives: The relationship between age-related diseases and chronic inflammation associated with aging has recently been investigated. This study aimed to investigate how chronic inflammation is associated with age-related hearing loss (ARHL). Methods: Twenty ARHL patients aged ≥65 years were prospectively enrolled from July 1 to 31 December 2015. Audiological tests and serological tests, such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), immunoglobulin G (IgG), interleukin 6 (IL-6), white blood cell (WBC) counts, neutrophil counts, lymphocyte counts, and platelet counts, were performed. The patients were divided into two groups: mild hearing loss group (n = 7) and moderate to profound hearing loss group (n = 13). Results: Immunoinflammatory biomarkers, such as CRP, ESR, and IL-6, and vascular inflammatory biomarkers, such as neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio, were higher in the moderate to profound hearing loss group. IgG, WBC counts, and neutrophil counts were similar in both groups. Conclusion: The present preliminary pilot study demonstrated that high levels of inflammatory biomarkers may be associated with ARHL. The results suggest a possible association between chronic inflammation and ARHL. Further well-designed studies of ARHL, based on a new perspective of chronic inflammation, should be performed.

The effective screening tools for detecting hearing loss in elderly population: HHIE-ST Versus TSQ

Background

Globally increasing number of elders is concerned. Hearing loss process in older adults cannot be avoided. An effective screening tool for hearing loss is essential for proper diagnosis and rehabilitation, which can improve QOL in older adults.

Methods

This prospective-diagnostic test study evaluates the diagnostic value of Thai version of the Hearing Handicap Inventory for Elderly Screening (HHIE-ST) and the Thai Single Question (TSQ) surveys in screening hearing disability in 1109 Thai participants aged 60 years and older in communities in four provinces in Thailand. The HHIE-ST consisted of 10 selected questions from the validated HHIE-Thai version. A TSQ survey was developed to have the same meaning as an English Single Question survey. The participants answered both questionnaires, and a standard audiometry test assessed with air conduction from 250 to 8000 Hz was included as a gold standard.

Results

The prevalence of hearing disability was 38.34%. The HHIE-ST achieved a sensitivity of 88.96% (95% CI 85.77–91.64) and specificity of 52.19% (95% CI 48.24–56.13) for diagnosis hearing disability in Thai older adults, whereas the TSQ yielded a sensitivity of 88.73% and a specificity of 55.93%. A combined test including the HHIE-ST and TSQ achieved better performance with sensitivity of 85.29% and specificity of 60.13%.

Conclusions

Either the HHIE-ST or the TSQ is a sensitive and useful tool for screening hearing disability in Thai older adults. Using the HHIE-ST together with the TSQ resulted in a better screening tool for detecting moderate hearing loss older adults who will benefit and recommended for hearing rehabilitation.

Trial registration

The study is registered with the following number in the Thai Clinical Trials Registry: TCTR20151015003. Date of registration October 14, 2015.

Quantitative criteria for age-related hearing loss using audiometric configuration analysis

OBJECTIVES

To suggest the most adaptable criteria of age-related hearing loss (ARHL) using prevalence matching with population-based data.

METHODS

We chose 30, 25, 20, and 15 dB as gap ranges of cutoff values of the descending type of hearing loss, between an average of low (500 Hz, 1 kHz) and high (4 kHz, 6 kHz) frequencies. Interaural difference was defined as 10 or 15 dB. Hearing loss was defined over 25 dB. We compared the prevalence results of the cross-matching criteria. We used population-based data from the Korea National Health and Nutrition Examination Survey. We assumed that the prevalence of ARHL ranged from 25 to 35%, and this prevalence will increase gradually with age.

RESULTS

Among the eight possible criteria, age ≥ 65 years, average of all frequencies > 25 dB at the each sides, gap between low- and high frequencies ≥ 20 dB, and interaural difference ≤ 10 dB were the most suitable criteria to suggest a quantitative definition of ARHL audiometrically.

CONCLUSION

In the current study, we recommend the new, quantitative ARHL criteria. The suggested criteria for ARHL might be easily accessed by other researchers to demonstrate their own hypotheses.

Hearing threshold levels among steel industry workers in Samut Prakan, Thailand

Background

Industrial noise is generally considered from the perspective of environmental health and safety, with requirements for reduced occupational noise exposure, strict standards for hearing protection, and public health awareness campaigns.

Materials and methods

This cross-sectional study aimed to identify the hearing threshold levels (HTLs) among steel industry workers exposed to hazardous noises in Samut Prakan Province, Thailand, and investigate the associations between hearing loss and age and length of employment in the industry. Audiometric data for 93 participants were collected at the Samut Prakan Provincial Hospital. Qualified technicians performed audiometric screening using an audiometer in a quiet environment. Tests were conducted after participants had completely rested for ≥14 hours after the last exposure to workplace noise.

Results

The results showed that all participants had been employed in a work zone with a noise hazard for >1 year. Participants’ age ranged from 19 to 59 years and their work experience from 1 to 39 years. Average mean hearing thresholds in the right ear at 4, 6, and 8 kHz were 31.34, 29.62, and 25.64 dB, respectively. Mean hearing thresholds in the left ear at 4, 6, and 8 kHz were 40.15, 32.20, and 25.48 dB, respectively. Hearing loss related to work experience was greater than that attributable to age and work station. Duration of noise exposure ranged from 1 to 39 years, and more than half of the participants (60.2%) were exposed to hazardous noises from 6 to 25 years.

Conclusion

These findings show that participants’ age and experience were significantly associated with hearing loss at all levels. HTLs among industrial workers should be regularly assessed. At the health policy level, these workers need to start being protected when they begin working.

Self-Reported Hearing/Visual Loss and Mortality in Middle-Aged and Older Adults: Findings From the Komo-Ise Cohort, Japan

Background

The association of sensory loss with mortality remains unclear. We aimed to explore the associations of hearing loss (HL), visual loss (VL), and dual sensory loss (DSL) with survival.

Methods

Data came from the Komo-Ise study cohort in Gunma Prefecture, Japan, where the community-dwelling residents aged 40–69 years were followed up from 1993 to 2010. We analyzed 9,522 individuals who answered the follow-up questionnaires in 2000 (average age 64 [range, 47 to 77] years in 2000). The primary exposures were “HL only,” “VL only,” or “DSL”, with “no HL/VL” as the reference. These sensory loss statuses were assessed by asking the difficulty in hearing conversation or reading newspaper even with aids in the follow-up questionnaires in 2000. All-cause and cause-specific mortality were ascertained from linkage to death certificate data. Cox proportional hazards models adjusting for confounders, including demographic factors, socioeconomic status, and health status, were used. Potential mediators (depression, walking disability, and social participation) were additionally adjusted for.

Results

There were 1,105 deaths over the 10-year follow-up. After adjustment for the potential confounders, HL and DSL were associated with increased all-cause mortality (hazard ratios of 1.74 [95% CI, 1.18–2.57] and 1.63 [95% CI, 1.09–2.42], respectively). Potential mediators explained a modest portion of the association. As for cause-specific mortality, HL was associated with increased cancer mortality, while VL and DSL were associated with increased cardiovascular disease mortality.

Conclusions

Self-reported HL and DSL may be risk factors of mortality among middle-aged or elderly Japanese populations.

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

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.

Age- and Gender-Related Mean Hearing Threshold in a Highly-Screened Population: The Korean National Health and Nutrition Examination Survey 2010-2012

Background

In evaluating hearing disability in medicolegal work, the apportionment of age- and gender-related sensorineural hearing loss should be considered as a prior factor, especially for the elderly. However, in the literature written in the English language no studies have reported on the age- and gender-related mean hearing threshold for the South Korean population.

Objective

This study aimed to identify the mean hearing thresholds in the South Korean population to establish reference data and to identify the age- and gender-related characteristics.

Methods

This study is based on the Korea National Health and Nutrition Examination Survey (KNHANES) 2010–2012, which was conducted by the Korean government, the data of which was disclosed to the public. A total of 15,606 participants (unweighted) representing 33,011,778 Koreans (weighted) with normal tympanic membrane and no history of regular or occupational noise exposure were selected and analyzed in this study. The relationship between the hearing threshold level and frequency, age, and gender was investigated and analyzed in a highly-screened population by considering the sample weights of a complex survey design.

Results

A gender ratio difference was found between the unweighted and the weighted designs: male:female, 41.0%: 59.0% (unweighted, participants) vs. 47.2%:52.8% (weighted, representing population). As age increased, the hearing threshold increased for all frequencies. Hearing thresholds of 3 kHz, 4 kHz, and 6 kHz showed a statistical difference between both genders for people older than 30, with the 4 kHz frequency showing the largest difference. This paper presents details about the mean hearing threshold based on age and gender.

Conclusions

The data from KNHANES 2010–2012 showed gender differences at hearing thresholds of 3 kHz, 4 kHz, and 6 kHz in a highly-screened population. The most significant gender difference in relation to hearing threshold was observed at 4 kHz. The hearing thresholds at all of the tested frequencies worsened with increasing age. The mean hearing thresholds suggested in this study will be useful for the formulation of healthcare-related hearing policies and used as reference data for disability ratings for hearing loss due to various causes.

Hearing Threshold, Loss, Noise Levels and Worker's Profiles of an Open Cast Chromite Mines in Odisha, India

OBJECTIVES

The aims of the study were to describe the noise levels at an open cast chromite mine in Odisha, India, and the hearing threshold of its workers and to associate their hearing loss with their age, work station and length of employment at the mine.

METHODS

We performed a cross-sectional study of the hearing threshold of chromite mine workers. Audiometric data from 500 subjects was collected at the mines' hospital in the Sukinda Valley of Jajpur, Odisha, India. The latest audiometry data available for the period 2002 to 2008 was used in the analysis. Audiometric screening was performed using an audiometer (TRIVENI TAM-25 6025A) in a quiet environment by qualified technicians, audiologists or physicians. Tests were conducted on the subjects after they had completely rested for 16 hours or more after their day shift.

RESULTS

A maximum of 262 subjects (52.4%) were employed in the work zone area and a minimum of 2 subjects (0.4%) had less than 5 years working experience. The age of the subjects ranged from 29 to 59 years and their working experience ranged from 4 to 37 years. The subjects' average mean hearing thresholds at 4, 6 and 8 kHz were 21.53 dBA, 23.40 dBA and 21.90 dBA, respectively. The maximum Leq and L90 levels exceeded the prescribed limits for commercial, residential and silence zones. The maximum Leq levels exceeded 95 dBA for large and medium heavy earth moving machineries (HEMMs), both outside and at the operator's position. Hearing loss due to the subjects' work experience was found to be greater than that attributable to age and workstation.

CONCLUSION

In our study population, the maximum noise levels for large and medium HEMMs and inside the cabins of HEMMs were found to be more than 95 dBA. This indicates that operators in this particular chromite mine at Odisha, India were exposed to noise levels exceeding 95 dBA for more than 10% of the monitoring time. The subjects' hearing loss was also found to increase for every 10-year age interval and that for every 5 years of work experience at high fence. The subjects' age and experience are significantly associated with hearing loss at all levels for frequencies of 4.0, 6.0, and 8.0 kHz, with older and more experienced workers having a higher incidence of hearing loss.

Prevalence and risk factors of hearing loss using the korean working conditions survey

Background and Objectives

The hearing loss of workers can occur when they are affected by age, otologic disease, and work-related risks such as noise and chemicals. Based on the Korean Working Conditions Survey (KWCS) in 2010, this research aimed to estimate the prevalence rate of hearing loss and to identify the risk factors affecting its occurrence.

Subjects and Methods

The subjects were 10019 employees who completed an interview conducted as part of KWCS in 2010. The prevalence rate of hearing loss according to sex, age, education, income, smoking, drinking, hypertension, industrial type, occupations, employment status, working period, and hazards at the workplace were assessed. The factors that could affect the occurrence of hearing loss were investigated based on a logistic regression analysis.

Results

The prevalence rate of hearing loss was 2.7%. In a logistic multivariate analysis, sex, age, occupations, working period, noise, and exposure to chemicals showed statistically significant correlations to the occurrence of hearing loss. The adjusted odd ratios were as follows: 1.74 [95% confidence interval (CI), 1.03-2.96] for males, 2.11 (95% CI, 1.14-3.89) for those in their 40s, 2.24 (95% CI, 1.19-4.20) for those in their 50s, 2.21 (95% CI, 1.18-4.15) for manage/professional works, 2.73 (95% CI, 1.69-4.41) for manufacturing, 2.07 (95% CI, 1.36-3.15) for those who have worked for more than 20 years, 1.72 (95% CI, 1.14-2.58) for noise exposure, 1.53 (95% CI, 1.02-2.30) for vibration exposure and 1.58 (95% CI, 1.11-2.24) for chemical exposure.

Conclusions

The overall occupational and non-occupational risk factors related to employees' hearing loss were reviewed. In addition to the exposure to noise, occupational risks of hearing loss, such as isolated exposure to vibration and chemicals, and combined exposure to noise and these hazards, were identified. Multiple exposure to hazards, along with prolonged noise exposure increased the risk of hearing loss.

Sex Differences in a Cross Sectional Study of Age-related Hearing Loss in Korean

Objectives

The purpose of this study was to obtain sex- and age-specific reference level for hearing threshold of normal aging in Korean and to determine if the rate of change in pure-tone hearing thresholds differed by sex.

Methods

Subjects were clients who visited the Health Promotion Center, Daegu Fatima Hospital, Daegu, Korea, from January 2004 to September 2005. Pure-tone audiometric measures were obtained from 3,470 subjects who also completed a hearing questionnaire. The slope of a linear regression was used to estimate the rate of change in pure-tone thresholds at 0.25 to 8 kHz for each ear in 214 men and 902 women without past history of otorrhea, usage of ototoxic drugs, head injury, job in noisy environment, and military service.

Results

Hearing thresholds were elevated with age in all test frequencies. Significant sex differences were found in pure-tone thresholds at 4 and 8 kHz after adjusting for age using analysis of covariance. In those high frequencies, hearing was worse in men than in women. The average rate of change in threshold was 0.28 and 0.24 dB per year at 0.25 kHz, increasing gradually to 1.27 and 1.05 dB per year at 8 kHz for men and women, respectively. Men had significantly faster rates of threshold increase at 4 and 8 kHz than women.

Conclusion

These cross-sectional measures of hearing levels and rate of threshold increases at 4 and 8 kHz showed significant sex differences in Korean men and women with little evidence of noise-induced hearing loss.

[Molecular mechanism of age-related hearing loss: toward its prevention]

Mitochondrial DNA (mtDNA) mutations/deletions and decline of mitochondrial function are considered to be associated with the development of age-related hearing loss (AHL). First, we examined age-related changes in gene expression profile in the cochlea of DBA/2J mouse. This mouse exhibited mild hearing loss at 2 months of age and became deaf by 8 months. Comprehensive gene expression analysis identified significant expression changes correlated with AHL in over 4000 cochlear genes. When compared to 2 month old mice, approximately 2,200 genes were downregulated and approximately 1,900 genes were upregulated in the cochlea of 8 month old mice. AHL-correlated genes in the cochlea of 8-month-old DBA/2J mice were statistically associated with 15 mitochondrial process categories, suggesting that AHL is associated with profound down-regulation of genes involved in the mitochondrial function in the cochlea of aged DBA/2J mice. Next, we assessed the role of accumulation of mtDNA mutations in the development of AHL using Polg (D257A) knock-in mouse, which exhibited increased spontaneous mtDNA mutation rates during aging and showed accelerated aging. They exhibited moderate hearing loss and degeneration and apoptosis in the cochlea by 9 month of age, while wild-type animals did not. MtDNA mutations were associated with transcriptional alterations consistent with impairment of energy metabolism, induction of apoptosis, and hearing dysfunction in the cochlea of aged mitochondrial mutator mice. Lastly, we examined if 26% calorie restriction (CR) could prevent AHL in C57BL/6 mice. CR mice retained normal hearing and showed no cochlear degeneration by 15 months of age, whereas control mice developed moderate hearing loss and cochlear degeneration due to increased apoptosis at 15 months of age. CR mice also showed a significant reduction in the number of TUNEL-positive cells and cleaved caspase-3-positive cells. Microarray analysis revealed that CR upregulated the expression of genes involved in mitochondrial and hearing function and downregulated that of apoptotic genes. Taken together, these findings suggest that accumulation of mtDNA mutations during aging leads to mitochondrial dysfunction and induces an apoptotic program, thereby causing AHL.

Age-dependent changes of gap detection in the Mongolian gerbil (Meriones unguiculatus)

Gap detection using broadband noise was characterized in a group of young gerbils from the breeding colony of the University of Regensburg (RB gerbils), old RB gerbils, and old gerbils from the breeding colony of the University of South Carolina (SC gerbils). Data from old RB and old SC gerbils were not significantly different and were subsequently combined for a comparison with data from the group of young RB gerbils. Level dependence of gap-detection thresholds in young and old domesticated gerbils resembled the typical mammalian pattern of level dependence. Gap-detection thresholds of old gerbils were significantly elevated at 30 dB SL and 50 dB SPL as compared with young gerbils. Compared with young gerbils tested at 30 dB SL and 50 dB SPL, the distribution of gap-detection thresholds in old gerbils was broader with a spread to higher gap-detection thresholds. Some old animals retained excellent temporal resolution, while some showed impaired gap detection. The gap-detection data collected in young and old gerbils resemble previously published data from humans of different age and confirm that gerbils are a useful model to study age-dependent changes in temporal processing.

Behavioral and evoked-potential thresholds in young and old Mongolian gerbils (Meriones unguiculatus)

Age-dependent hearing loss has been well documented in gerbils exceeding 2 years of age using physiological methods (e.g. [Mills et al. (1990) Hear. Res. 46, 201-210]). We determined behavioral thresholds for broad-band noise and pure-tone pulses in gerbils as a function of age. Contrary to expectations based on previously published physiological data, we found no significant (broad-band noise and 10 kHz) or only a very small hearing loss (7 dB at 2 kHz) in 30-36-month-old animals. In animals over 3 years of age we observed an increased spread of thresholds and threshold shifts exceeding 20 dB in some individuals. Behavioral thresholds of old gerbils from two breeding colonies (University of Regensburg and Medical University of South Carolina) were similar. Data from individual animals where thresholds were determined physiologically and behaviorally indicate that results from auditory brainstem response measurements show no shift at 18 months while subsequent measurements at 28-29 months revealed age-dependent threshold shifts of 10-15 dB. In contrast, thresholds determined by behavioral methods in these same individuals at 31-33 months of age remained stable.