Biomarkers of Systemic Inflammation and Risk of Incident Hearing Loss

Environmental Risk Factors, Protective Factors, and Biomarkers for Hearing Loss: An Umbrella Review

OBJECTIVE

We aimed to investigate the potential environmental risk factors, protective factors, and biomarkers of hearing loss (HL), and establish a hierarchy of evidence.

DATA SOURCES

Embase, PubMed, Cochrane Library, and Web of Science electronic database from inception to June 1, 2023.

REVIEW METHODS

We included meta-analyses of observational studies of associations between HL and environmental risk factors, protective factors, or biomarkers. We calculated summary effect estimates, 95% confidence interval, heterogeneity I2 statistic, 95% prediction interval, small study effects, and excess significance biases.

RESULTS

Of the 9211 articles retrieved, 60 eligible articles were included. The 60 eligible articles identified 47 potential environmental risk and protective factors (N = 4,123,803) and 46 potential biomarkers (N = 173,701). Evidence of association was convincing (class I) for rheumatoid arthritis (RA) and every 1 cm increase in height. Evidence of association was highly suggestive (class II) for human immunodeficiency virus (HIV), diabetes, cumulative noise exposure (CNE), smoking, congenital cytomegalovirus (CMV) infection, combined exposure to organic solvents and noise, non-Gaussian noise exposure, each 1 kg increase in birth weight, noise exposure, and alopecia areata (AA).

CONCLUSION

In this umbrella review, RA, every 1 cm increase in height, HIV, diabetes, CNE, smoking, congenital CMV infection, combined exposure to organic solvents and noise, non-Gaussian noise exposure, each 1 kg increase in birth weight, noise exposure, and AA were strongly associated with HL.

The inflammatory and metabolic status of patients with sudden-onset sensorineural hearing loss

Introduction

Sudden sensorineural hearing loss (SSNHL) is a common emergency symptom in otolaryngology that requires immediate diagnosis and treatment. SSNHL has a multifactorial etiology, and its pathophysiologic mechanisms may be associated with inflammatory and metabolic changes that may affect the cochlear microenvironment or its nervous component, thus triggering the process or hindering hearing recovery. Therefore, the aim of this study was to assess metabolic and inflammatory changes to identify systemic parameters that could serve as prognostic factors for hearing recovery in patients with SSNHL.

Materials and methods

Thirty patients with a sudden hearing loss of at least 30 dB in three contiguous frequencies were enrolled in this study. Patients were followed up for 4 months and peripheral blood samples were collected at 7 days (V1), 30 days (V2) and 120 days (V3). Interleukins (IL)-1F7, IL-2, IL-4, IL-5, IL-6, IL-10, interferon γ (IFN-γ), tumor necrosis factor α (TNF-α) and adiponectin were quantified in serum. In addition, lipid and glycemic profiles as well as concentration of creatinine, uric acid, fructosamine, peroxide, total proteins and albumin were analyzed. Patients underwent weekly ear-specific hearing tests with standard pure tone thresholds for frequencies of 250-8,000 Hz, speech recognition threshold and word recognition score.

Results

Patients with SSNHL were divided into a group of patients who did not achieve hearing recovery (n = 14) and another group who achieved complete and significant recovery (n = 16). Most serologic parameters showed no significant changes or values indicating clinical changes. However, IFN-γ levels decreased by 36.3% between V1 and V2. The cytokine TNF-α showed a statistically significant decrease from V1 to V3 (from 22.91 to 10.34 pg./mL). Adiponectin showed a decrease from 553.7 ng/mL in V1 to 454.4 ng/mL in V3.

Discussion

Our results show that serologic cytokine levels change in the acute phase of manifestation of SSNHL and establish a parallel between systemic changes and improvements in hearing, especially TNF-α, which showed differences in hearing recovery. The use of IFN-γ, TNF-α and adiponectin may elucidate the clinical improvement in these patients.

Longitudinal urinary neopterin is associated with hearing threshold change over time in independent older adults

Low-grade chronic inflammation is associated with many age-related conditions. Non-invasive methods to monitor low-grade chronic inflammation may improve the management of older people at risk of poorer outcomes. This longitudinal cohort study has determined baseline inflammation using neopterin volatility in monthly urine samples of 45 independent older adults (aged 65-75 years). Measurement of neopterin, an inflammatory metabolite, enabled stratification of individuals into risk categories based on how often in a 12-month period their neopterin level was raised. Hearing was measured (pure-tone audiometry) at baseline, 1 year and 3 years of the study. Results show that those in the highest risk category (neopterin raised greater than 50% of the time) saw greater deterioration, particularly in high-frequency, hearing. A one-way Welch's ANOVA showed a significant difference between the risk categories for change in high-frequency hearing (W (3, 19.6) = 9.164, p = 0.0005). Despite the study size and duration individuals in the highest risk category were more than twice as likely to have an additional age-related morbidity than those in the lowest risk category. We conclude that volatility of neopterin in urine may enable stratification of those at greatest risk of progression of hearing loss.

Plasma Levels of Interleukin 2 (IL-2) Associated with Hearing Loss Evaluation in the Elderly

CONTEXT

Presbycusis can be mediated by the effects of inflammatory processes on the auditory system, and these aging biological mechanisms remain poorly studied.

AIMS

The aim of this study was to determine whether plasma biomarkers are associated with hearing disorders caused by aging in the elderly.

SETTINGS AND DESIGN

Cross-sectional study with 106 participants in the Active Aging Project, 93 (88%) females and 13 (12%) males, with an average age of 70 years.

METHODS AND MATERIAL

Audiological evaluation was performed with pure tone audiometry and collection of peripheral blood for the measurement of plasma levels of interleukins 2, 4, 6, and 10, tumor necrosis factor-α, and interferon-γ by means of flow cytometry.

STATISTICAL ANALYSIS USED

The SPSS (v.0, SPSS Inc., Chicago, USA) was used for the analysis of the data obtained. For all data analyzed, the significance level adopted was P < 0.05 and 95% confidence interval.

RESULTS

There were statistically significant correlations between male and IL-2 (P = 0.031; rs = 0.210), mean II of the right ear (P = 0.004; rs = 0.279), longer in years (P = 0.002; rs = 0.307) and in hours (P = 0.004; rs = 0.281) of noise exposure also in males.

CONCLUSIONS

In the present study, there was an association between the male gender and higher plasma levels of IL-2, an increase in the average hearing in the right ear, and greater time in years and hours of exposure to noise. There was a predominance of mild sensorineural hearing loss and worsening of hearing related to age, characteristics of presbycusis.

Plasma Levels of Interferon Gamma associated with Hearing Loss and Hearing Loss Sensation through the Handicap Questionnaire Inventory for the Elderly Screening Version

OBJECTIVE

The aim of this study was to verify the association between the auditory handicap found in the Hearing Handicap Inventory for the Elderly-Screening Version (HHIE-S) questionnaire and hearing loss and the plasma levels of inflammatory biomarkers.

MATERIALS AND METHODS

Cross-sectional study with 76 participants, 67 (88%) females and 9 (12%) males, with a mean age of 70 years. Tonal threshold audiometry and self-assessment with HHIE-S questionnaire were performed to measure the plasma levels of interleukin-2 (IL-2), IL-4, IL-6, and IL-10; tumor necrosis factor alpha; and interferon gamma (IFN-γ) flow cytometry method. For all data analyzed, the significance level adopted was P < 0.05 and 95% confidence interval.

RESULTS

An inverse correlation was observed between the increase in plasma levels of IFN-γ and normal auditory handicap (P = 0.015; rs = -0.280). The severe handicap group showed an increase in the averages I (P = 0.005; rs = 0.350) and II (P = 0.016; rs = 0.368) in the right ear and the light/moderate handicap group increased the means I (P = 0.027; rs = 0.350) and II (P = 0.046; rs = 0.310) of the left ear. A statistically significant association was found between the speech recognition threshold (SRT) test results of the right ear and the severe handicap group (P = 0.002; rs = 0.271).

CONCLUSIONS

There was an association between the increase in plasma levels of IFN-γ and normal auditory handicap. Additionally, statistically significant associations were observed between the mild/moderate and severe handicap groups with the increase in hearing means and an increase in SRT associated with the severe handicap group.

Association between hearing loss and high-sensitivity C-reactive protein: the Kangbuk Samsung Cohort Study

Background

Hearing loss (HL) is linked to an elevated risk of cardiovascular diseases (CVDs). The pathogeneses of HL and CVD commonly involve inflammatory responses. Previous studies investigated elevated levels of inflammatory biomarkers in subjects with HL, however, their findings did not demonstrate statistical significance. In our cross-sectional and longitudinal study, we investigated the correlation between HL and increased high-sensitivity C-reactive protein (hsCRP) levels to determine how HL is associated with CVDs.

Methods

We conducted a cross-sectional study with workers aged over 18 years who underwent health check-ups at our institution between 2012 and 2018 (n = 566,507), followed by conducting a longitudinal study of workers aged > 18 who underwent health checkups at least twice at our institution between 2012 and 2018 (n = 173,794). The definition of HL was as an average threshold of ≥ 20 dB in pure-tone air conduction at 0.5, 1.0, and 2.0 kHz in both ears. The incidence of increased hsCRP levels throughout the follow-up period was defined as a level exceeding 3 mg/L. Logistic regression and generalized estimating equations were performed to estimate the risk of increased hsCRP levels according to the occurrence of HL in groups stratified by age.

Results

In the cross-sectional study, the multivariate-adjusted odds ratio (OR) was 1.17 (95% confidence interval [CI]: 1.02-1.34); the OR was 0.99 (95% CI: 0.80-1.22) in those under 40 and 1.28 (1.08-1.53) in those over 40. In the longitudinal study, the multivariable-adjusted OR was 1.05 (95% CI: 0.92-1.19); the OR was 1.10 (95% CI: 0.90-1.35) in those under 40 and 1.20 (1.01-1.43) in those over 40.

Conclusions

This cross-sectional and longitudinal study identified an association between HL and increased hsCRP levels in workers aged over 40 years.

Hearing Impairment and Allostatic Load in Older Adults

Importance

Allostatic load, the cumulative strain that results from the chronic stress response, is associated with poor health outcomes. Increased cognitive load and impaired communication associated with hearing loss could potentially be associated with higher allostatic load, but few studies to date have quantified this association.

Objective

To investigate if audiometric hearing loss is associated with allostatic load and evaluate if the association varies by demographic factors.

Design, Setting, Participants

This cross-sectional survey used nationally representative data from the National Health and Nutrition Examination Survey. Audiometric testing was conducted from 2003 to 2004 (ages 20-69 years) and 2009 to 2010 (70 years or older). The study was restricted to participants aged 50 years or older, and the analysis was stratified based on cycle. The data were analyzed between October 2021 and October 2022.

Exposure

A 4-frequency (0.5-4.0 kHz) pure tone average was calculated in the better-hearing ear and modeled continuously and categorically (<25 dB hearing level [dB HL], no hearing loss; 26-40 dB HL, mild hearing loss; ≥41 dB HL, moderate or greater hearing loss).

Main Outcome and Measures

Allostatic load score (ALS) was defined using laboratory measurements of 8 biomarkers (systolic/diastolic blood pressure, body mass index [calculated as weight in kilograms divided by height in meters squared], and total serum and high-density lipoprotein cholesterol, glycohemoglobin, albumin, and C-reactive protein levels). Each biomarker was assigned a point if it was in the highest risk quartile based on statistical distribution and then summed to yield the ALS (range, 0-8). Linear regression models adjusted for demographic and clinical covariates. Sensitivity analysis included using clinical cut points for ALS and subgroup stratification.

Results

In 1412 participants (mean [SD] age, 59.7 [5.9] years; 293 women [51.9%]; 130 [23.0%] Hispanic, 89 [15.8%] non-Hispanic Black, and 318 [55.3%] non-Hispanic White individuals), a modest association was suggested between hearing loss and ALS (ages 50-69 years: β = 0.19 [95% CI, 0.02-0.36] per 10 dB HL; 70 years or older: β = 0.10 [95% CI, 0.02-0.18] per 10 dB HL) among non-hearing aid users. Results were not clearly reflected in the sensitivity analysis with clinical cut points for ALS or modeling hearing loss categorically. Sex-based stratifications identified a stronger association among male individuals (men 70 years or older: β = 0.22 [95% CI, 0.12-0.32] per 10 dB HL; women: β = 0.08 [95% CI, -0.04 to 0.20] per 10 dB HL).

Conclusion and Relevance

The study findings did not clearly support an association between hearing loss and ALS. While hearing loss has been shown to be associated with increased risk for numerous health comorbidities, its association with the chronic stress response and allostasis may be less than that of other health conditions.

Association of inflammatory markers with hearing loss in young adults

OBJECTIVES

To assess the correlation between inflammatory markers (IM) and hearing loss (HL) in a large cohort of apparently healthy individuals.

DESIGN

A cross sectional study.

SETTING

Tel-Aviv Medical Center (a tertiary referral center) Inflammatory Survey Participants Individuals who attended the Tel-Aviv Medical Center Inflammatory Survey (TAMCIS) for a routine annual health check.

RESULTS

Out of 2,500 individuals included in the final study cohort, 1,170 (47.3%) had some hearing impairment. Those with a hearing loss in 1 or both ears had significantly higher levels of neutrophils, lymphocytes, neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, and red blood cell counts. There was a difference between low- and high- frequencies losses associated with the inflammatory status.

CONCLUSIONS

IM levels were associated with the presence of a HL, supporting a link between inflammatory changes and hearing loss.

Analysis of Serum Inflammatory Markers in Infants Under 6 Months of Age with Non-Syndromic Moderate and Severe Hearing Loss Associated with GJB2 Gene Mutations

BACKGROUND The GJB2 gene is reported to be the main hereditary factor responsible for non-syndromic hearing impairment in infants. Several kinds of hearing loss have been linked to elevated inflammatory markers. This study aimed to evaluate serum levels of IL-2, IL-4, IL-6, IL-10, IL-17, alpha-TNF, and γ-IFN and the severity of hearing loss. MATERIAL AND METHODS Ninety newborns were divided into 3 groups: severe hearing impairment (31 infants), moderate hearing impairment (30 infants), and normal hearing (29 infants). Hearing screening was performed using otoacoustic emissions test. Mutations of the GJB2 gene were detected with Sanger sequencing. The patients had DNFB1 mutation. Seven blood inflammatory markers were tested using Cytometric Bead Array. We performed the t test to examine differences in expression of 7 inflammatory markers between sexes in the groups. The correlation between indicators within groups was studied using the Pearson correlation test. Correlation of different indicators among groups was studied using the Spearman correlation test. RESULTS When compared among the 3 groups (severe, moderate hearing impairment, and normal hearing group), we found that IL-10 had a positive correlation with the severity of GJB2-associated hearing loss, which was statistically significant (P<0.05). CONCLUSIONS This research aimed to assess the relationship of 7 serum inflammatory markers with GJB2-associated hearing loss in infants. Inflammatory marker IL-10 had a positive correlation with the severity of GJB2-associated infant hearing loss, and it might have the potential to become a future therapeutic target.

Relationship of hearing impairment, social participation and depressive symptoms to the incidence of frailty in a community cohort

BACKGROUND

The mediating effect of social participation and depressive symptoms on the relationship between hearing impairment and frailty remains unclear.

METHODS

A total of 3981 participants from three waves of the China Health and Retirement Longitudinal Study (CHARLS) were included. The outcome was incidental frailty. Hearing impairment, social participation, and depressive symptoms were the main variables. Cox regression models and structural equation models were adopted to examine the relationship between hearing impairment, social participation, depressive symptoms, and the incidence of frailty, with adjustments for demographic characteristics and lifestyle variables at baseline.

RESULTS

Hearing impairment (hazard ratio [HR] 1.31, 95% confidence interval [CI] 1.12, 1.74), social participation (HR 0.72, 95% CI 0.55, 0.94), and depressive symptoms (HR 1.78, 95% CI 1.37, 2.30) were associated with the incidence of frailty. Hearing impairment was associated with frailty not only through social participation (β = 0.015, 95% CI 0.003, 0.037) and depressive symptoms (β = 0.070, 95% CI 0.037, 0.116) separately but also through social participation and depressive symptoms sequentially (β = 0.002, 95% CI 0.001, 0.004). Furthermore, the effect of social participation on frailty occurred in participants with hearing impairment, while the effect of depressive symptoms on frailty occurred in participants with normal hearing status.

CONCLUSIONS

Hearing impairment is associated with frailty, in which social participation and depressive symptoms partly mediate the association. The effect of social participation and depressive symptoms on frailty varies across hearing statuses. Integrated and comprehensive intervention measures, including hearing screenings, promoting social participation, and improving depressive symptoms, are suggested to prevent frailty.

Allostatic load and risk of hearing impairment

Background

Methods

Results

Conclusions

•

Allostatic load captures cumulative physiological stress which has consequence for subsequent hearing function.

•

Prolonged high allostatic load was associated with risk of objectively measured hearing impairment.

•

This association is shown in nationally representative longitudinal ageing study.

Extracellular Biomarkers of Inner Ear Disease and Their Potential for Point-of-Care Diagnostics

Rapid diagnostic testing has become a mainstay of patient care, using easily obtained samples such as blood or urine to facilitate sample analysis at the point-of-care. These tests rely on the detection of disease or organ-specific biomarkers that have been well characterized for a particular disorder. Currently, there is no rapid diagnostic test for hearing loss, which is one of the most prevalent sensory disorders in the world. In this review, potential biomarkers for inner ear-related disorders, their detection, and quantification in bodily fluids are described. The authors discuss lesion-specific changes in cell-free deoxyribonucleic acids (DNAs), micro-ribonucleic acids (microRNAs), proteins, and metabolites, in addition to recent biosensor advances that may facilitate rapid and precise detection of these molecules. Ultimately, these biomarkers may be used to provide accurate diagnostics regarding the site of damage in the inner ear, providing practical information for individualized therapy and assessment of treatment efficacy in the future.

The Inverted-U Relationship Between Dietary Inflammatory Potential and Hearing Loss Among Adults Aged 20 Years and Over in the United States: A Cross-Sectional Study

Purpose

The purpose of this study was to examine the relationship between dietary inflammatory index and objective hearing loss (HL).

Materials and Methods

A cross-sectional analysis of a nationally representative sample of participants was performed based on data in National Health and Nutrition Examination Survey (NHANES) (2009-2016). HL was defined as pure tone averages >25 dB at 500, 1000, and 2000 Hz (low frequency); 3000, 4000, 6000, and 8000 Hz (high frequency) in either ear. The energy-adjusted dietary inflammatory index (E-DII) score was calculated for each participant based on two 24-h dietary recalls to assess diet-associated inflammation. Multivariable logistic regression was used to examine the linear relationship between HL and E-DII score or E-DII quartiles. Restricted cubic spline was applied to identify any non-linear associations of the E-DII score with hearing loss. Subgroup analyses were performed by age and gender to explore the moderating roles of these factors. Akaike's Information Criterion (AIC) values were used to select the better-fitted model among linear and non-linear models.

Results

An inverted-U shaped relationship with low-frequency hearing loss (LFHL) was identified for the E-DII score (P-nonlinear =0.023) after adjustment for potential confounders. But significant linear or nonlinear association between E-DII score and high-frequency hearing loss (HFHL) was not found.

Conclusion

E-DII score had inverted-U relationship with LFHL. Both pro-inflammatory diet and anti-inflammatory diet seemed to be associated with a decreased risk of LFHL compared to diet that was neither pro-inflammatory diet nor anti-inflammatory diet.

Diet Quality and the Risk of Impaired Speech Reception Threshold in Noise: The UK Biobank cohort

OBJECTIVE

Previous studies have examined the association between several diet quality indexes and risk of hearing loss, based on self-reported information or on audiometry test, with inconsistent results. However, the impact of healthy diets on the capacity to listening in noise, a proxy of disability due to hearing loss, is unknown. This research assessed the prospective association between five diet quality indexes and the speech reception threshold in noise in the UK Biobank study.

DESIGN

Prospective cohort with 105,592 participants aged ≥40 years. At baseline, adherence to the Mediterranean Diet Adherence Screener, the alternate Mediterranean Diet score, the Dietary Approaches to Stop Hypertension, the Alternate Healthy Eating Index-2010, and the healthful Plant-Based Diet Index were assessed. Functional auditory capacity was measured with a digit triplet test, and impairment was defined as a speech reception threshold in noise >-3.5 dB in any physical exam during the follow-up.

RESULTS

Over a median follow-up of 3.2 (SD: 2.1) years, 1704 participants showed impaired speech reception threshold in noise. After adjusting for potential confounders, the hazard ratios (95% confidence interval) of impairment per 1-SD increase in the Mediterranean Diet Adherence Screener, alternate Mediterranean Diet score, Dietary Approaches to Stop Hypertension, Alternate Healthy Eating Index-2010 and healthful Plant-Based Diet Index scores were, respectively, 0.98 (0.94 to 1.03), 1.01 (0.96 to 1.06), 1.02 (0.97 to 1.07), 1.01 (0.96 to 1.06), and 1.00 (0.96 to 1.05). Results were similar when analyses were restricted to those >60 years, with British ethnicity, without chronic disease, without tinnitus or with optimal cognitive function.

CONCLUSIONS

Adherence to a healthy diet did not show an association with the speech reception threshold in noise. More research is needed to identify the impact of individual foods or nutrients on this outcome.

The inflammatory potential of the diet is prospectively associated with subjective hearing loss

PURPOSE

We investigated the association between the inflammatory potential of the diet and hearing loss in the context of aging.

METHODS

We studied 3435 French adults enrolled in the SU.VI.MAX 2 (2007-2009) cohort. The inflammatory potential of the diet was estimated by the Dietary Inflammatory Index (DII^®) using ≥ 3 baseline 24-h dietary records. Subjective hearing loss was assessed after a mean of 12.5 ± 0.7 years by 3 individual items (ability to carry a conversation in a noisy setting, frequently asking for repetition, and need to increase the television/radio volume) and by a composite score, dichotomized for analyses. We fit sex-specific multivariable logistic regression models.

RESULTS

Compared with males, females had higher DII scores (i.e., more pro-inflammatory diet) and less subjective hearing loss. Among males, a significant positive association between DII (continuous scale) and inability to carry a conversation in a noisy setting was found (OR = 1.10; 95% CI 1.02, 1.18), while the opposite was seen among females (OR = 0.92; 95% CI 0.87, 0.98). Regarding the need to turn up the television/radio volume, a significant positive association with DII (continuous scale) was found only among males (OR = 1.09; 95% CI 1.01, 1.18). A significant association with the subjective hearing loss composite score was found among females (OR_{Q3 vs Q1} = 0.74; 95% CI 0.57, 0.97).

CONCLUSION

The findings among males supported the hypothesis that a pro-inflammatory diet could increase risk of hearing loss, whereas the findings among females were unexpected. This study could provide impetus for future research in sensory disability and aging.

TRIAL REGISTRATION

www.clinicaltrials.gov # NCT00272428.