Sex differences in noise-induced hearing loss: a cross-sectional study in China

The curvature quantification of wave I in auditory brainstem responses detects cochlear synaptopathy in human beings

PURPOSE

Patients with age-related hearing loss complain often about reduced speech perception in adverse listening environment. Studies on animals have suggested that cochlear synaptopathy may be one of the primary mechanisms responsible for this phenomenon. A decreased wave I amplitude in supra-threshold auditory brainstem response (ABR) can diagnose this pathology non-invasively. However, the interpretation of the wave I amplitude in humans remains controversial. Recent studies in mice have established a robust and reliable mathematic algorithm, i.e., curve curvature quantification, for detecting cochlear synaptopathy. This study aimed to determine whether the curve curvature has sufficient test-retest reliability to detect cochlear synaptopathy in aging humans.

METHODS

Healthy participants were recruited into this prospective study. All subjects underwent an audiogram examination with standard and extended high frequencies ranging from 0.125 to 16 kHz and an ABR with a stimulus of 80 dB nHL click. The peak amplitude, peak latency, curvature at the peak, and the area under the curve of wave I were calculated and analyzed.

RESULTS

A total of 80 individuals with normal hearing, aged 18 to 61 years, participated in this study, with a mean age of 26.4 years. Pearson correlation analysis showed a significant negative correlation between curvature and age, as well as between curvature and extended high frequency (EHF) threshold (10-16 kHz). Additionally, the same correlation was observed between age and area as well as age and EHF threshold. The model comparison demonstrated that the curvature at the peak of wave I is the best metric to correlate with EHF threshold.

CONCLUSION

The curvature at the peak of wave I is the most sensitive metric for detecting cochlear synaptopathy in humans  and may be applied in routine diagnostics to detect early degenerations of the auditory nerve.

Exploring the Prevalence of Tinnitus and Ear-Related Symptoms in China After the COVID-19 Pandemic: Online Cross-Sectional Survey

BACKGROUND

Tinnitus is a complex and heterogeneous disease that has been identified as a common manifestation of COVID-19. To gain a comprehensive understanding of tinnitus symptoms in individuals following COVID-19 infection, we conducted an online survey called the China Ear Nose and Throat Symptom Survey in the COVID-19 Pandemic (CENTSS) among the Chinese population.

OBJECTIVE

Our objective was to investigate tinnitus and ear-related symptoms after COVID-19 infection in the Chinese population, with the aim of providing a solid empirical foundation for improved health care. The findings from CENTSS can contribute to the development of enhanced management strategies for tinnitus in the context of long COVID. By gaining a better understanding of the factors contributing to tinnitus in individuals with COVID-19, health care providers can tailor interventions to address the specific needs of affected patients. Furthermore, this study serves as a basis for research on the long-term consequences of COVID-19 infection and its associated tinnitus symptoms.

METHODS

A quantitative, online, cross-sectional survey study design was used to explore the impact of the COVID-19 pandemic on experiences with tinnitus in China. Data were collected through an online questionnaire designed to identify the presence of tinnitus and its impacts. Descriptive statistics were used to analyze individuals' demographic characteristics, COVID-19 infection-related ear symptoms, and the cognitive and emotional implications of tinnitus. Univariable and multivariable logistic regression analyses were used to model the cross-sectional baseline associations between demographic characteristics, noise exposure, educational level, health and lifestyle factors, and the occurrence of tinnitus.

RESULTS

Between December 19, 2022, and February 1, 2023, we obtained responses from 1262 Chinese participants representing 24 regions, with an average age of 37 years. Among them, 540 patients (42.8%) reported experiencing ear-related symptoms after COVID-19 infection. Only 114 (9%) of these patients sought medical attention specifically for their ear symptoms, while 426 (33.8%) did not seek hospital care. Tinnitus emerged as the most prevalent and impactful symptom among all ear-related symptoms experienced after COVID-19 infection. Of the respondents, female participants (688/888, 77.78%), younger individuals (<30 years), individuals with lower education levels, participants residing in western China, and those with a history of otolaryngology diseases were more likely to develop tinnitus following COVID-19 infection.

CONCLUSIONS

In summary, tinnitus was identified as the most common ear-related symptom during COVID-19 infection. Individuals experiencing tinnitus after COVID-19 infection were found to have poorer cognitive and emotional well-being. Different ear-related symptoms in patients post-COVID-19 infection may suggest viral invasion of various parts of the ear. It is therefore crucial to monitor and manage hearing-related changes resulting from COVID-19 as clinical services resume.

Association of noise exposure, plasma microRNAs with metabolic syndrome and its components among Chinese adults

AIMS

We aimed to evaluate the association of occupational noise with metabolic syndrome (MetS) and its components, and to assess the potential role of miRNAs in occupational noise-associated MetS.

METHODS

A total of 854 participants were enrolled in our study. Cumulative noise exposure (CNE) was estimated in conjunction with workplace noise test records and research participants' employment histories. Logistic regression models adjusted for potential confounders were used to assess the association of CNE and miRNAs with MetS and its components.

RESULTS

We observed linear positive dose-response associations between occupational noise exposure and the prevalence of MetS (OR: 1.031; 95 % CI: 1.008, 1.055). And linear and nonlinear relationship were also found for the association of occupational noise exposure with high blood pressure (OR: 1.024; 95 % CI: 1.007, 1.041) and reduced high-density lipoprotein (OR: 1.051; 95 % CI: 1.031, 1.072), respectively. MiR-200a-3p, miR-92a-3p and miR-21-5p were inversely associated with CNE, or the prevalence of MetS and its components (all P < 0.05). However, we did not find any statistically significant mediation effect of miRNAs in the associations of CNE with MetS. Furthermore, the prevalence of bilateral hearing loss in high-frequency increased (OR: 1.036; 95 % CI: 1.008, 1.067) with CNE level rising, and participants with bilateral hearing loss in high-frequency had a significantly higher risk of MetS (OR: 1.727; 95 % CI: 1.048, 2.819).

CONCLUSION

Our study suggests that occupational noise exposure is associated with MetS and its components, and the role of miRNAs in noise-induced increasing MetS risk needs to be confirmed in future studies.

Impact of occupational noise exposure on the hearing level in hospital staffs: a longitudinal study

The study aimed to evaluate the impact of occupational noise on hearing loss among healthcare workers using audiometry. A longitudinal study was conducted with a six-month follow-up period in a hospital with 21 participants, divided into high-noise-exposure (HNE) and low-noise-exposure (LNE) groups. Mean noise levels were higher in the HNE group (70.4 ± 4.5 dBA), and hearing loss was measured using pure-tone audiometry at baseline and follow-up. The HNE group had significantly higher mean threshold levels at frequencies of 0.25 kHz, 0.5 kHz, 4.0 kHz, and an average of 0.5, 1, 2, and 4 kHz (all p-values < 0.05) after the follow-up period. After adjusting for confounding factors, the HNE group had significantly higher hearing loss levels at 0.25 kHz, 0.5 kHz, and average frequencies of 0.5, 1, 2, and 4 kHz compared to the LNE group at the second measurement. Occupational noise levels above 65 dBA over six months were found to cause significant threshold changes at frequencies of 0.25 kHz, 0.5 kHz, and an average of 0.5-4.0 kHz. This study highlights the risk of noise-induced hearing loss among healthcare workers and emphasizes the importance of implementing effective hearing conservation programs in the workplace. Regular monitoring and assessment of noise levels and hearing ability, along with proper use of personal protective equipment, are crucial steps in mitigating the impact of occupational noise exposure on the hearing health of healthcare workers.

Alterations of resting-state functional network connectivity in patients with noise-induced hearing loss: A study based on independent component analysis

Functional reorganization is a response to auditory deficits or deprivation, and less is known about the overall brain network alterations involving resting-state networks (RSNs) and multiple functional networks in patients with occupational noise-induced hearing loss (NIHL). So this study evaluated resting-state functional network connectivity (FNC) alterations in occupational NIHL using an independent component analysis (ICA). In total, 79 mild NIHL patients (MP), 32 relatively severe NIHL patients (RSP), and 84 age- and education- matched healthy controls (HC) were recruited. All subjects were tested using the Mini-mental State Examination scale, the tinnitus Handicap Inventory scale, the Hamilton Anxiety scale (HAMA) and scanned by T1-3DFSPGR, resting-state functional magnetic resonance imaging sequence in 3.0 T and analysed by the ICA. Seven RSNs were identified, compared with the HC, the MP showed increased FNC within the executive control network (ECN) and enhanced FNC within the default mode network (DMN) and the visual network (VN); compared with the HC, the RSP showed decreased FNC within the ECN and auditory network (AUN), DMN and VN; no significant changes in FNC were found in the MP compared with the RSP. Furthermore, the correlation analysis between the noise exposure time and hearing loss level, HAMA were both negative, and there were no significant correlations between the abnormal RSNs and the hearing level, noise exposure time and HAMA. These findings indicate that different degrees of NIHL involve different alterations in RSNs connectivity and may reveal the neural mechanisms related to emotion-related features and functional abnormalities following long-term NIHL.

Quantitative levels of noise exposure and 20-year hearing decline: findings from a prospective cohort study (the HUNT Study)

OBJECTIVE

We aimed to assess the association between occupational noise exposure and long-term hearing decline.

DESIGN

This prospective cohort study used linear regression to investigate the association between occupational noise exposure and 20-year hearing decline, adjusted for important confounders.

STUDY SAMPLE

The Norwegian cohort (N = 4,448) participated in two population-based health studies with pure-tone audiometry; HUNT2 1996-1998 and HUNT4 2017-2019. Exposure assessments included a quantitative job exposure matrix (JEM) and questionnaires.

RESULTS

The participants (40.2% men, 20-39 years at baseline) had a mean 20-year decline (3-6 kHz) of 11.3 ± 9.8 decibels (dB). There was a positive association between 20-year logarithmic average noise level (JEM-based, LEX,20y) and 20-year hearing decline among men. Compared with no exposure ≥80 dB during follow-up, minimum 5 years of exposure ≥85 dB (JEM-based) predicted 2.6 dB (95% CI: 0.2-5.0) larger 20-year decline for workers aged 30-39 years at baseline, and -0.2 dB (95% CI: -2.2 to 1.7) for workers aged 20-29 years. Combining JEM information with self-reported noise exposure data resulted in stronger associations.

CONCLUSION

This large longitudinal study shows an association between JEM-based noise exposure level and increased 20-year hearing decline among men. Contrary to expectations, the associations were weaker among younger workers, which might reflect a latency period.

Voluntary wheel exercise ameliorates cognitive impairment, hippocampal neurodegeneration and microglial abnormalities preceded by demyelination in a male mouse model of noise-induced hearing loss

Acquired peripheral hearing loss (APHL) in midlife has been identified as the greatest modifiable risk factor for dementia; however, the pathophysiological neural mechanisms linking APHL with an increased risk of dementia remain to be elucidated. Here, in an adult male mouse model of noise-induced hearing loss (NIHL), one of the most common forms of APHL, we demonstrated accelerated age-related cognitive decline and hippocampal neurodegeneration during a 6-month follow-up period, accompanied by progressive hippocampal microglial aberrations preceded by immediate-onset transient elevation in serum glucocorticoids and delayed-onset sustained myelin disruption in the hippocampus. Pretreatment with the glucocorticoid receptor antagonist RU486 before stressful noise exposure partially mitigated the early activation of hippocampal microglia, which were present at 7 days post noise exposure (7DPN), but had no impact on later microglial aberrations, hippocampal neurodegeneration, or cognitive decline exhibited at 1 month post noise exposure (1MPN). One month of voluntary wheel exercise following noise exposure barely affected either the hearing threshold shift or hippocampal myelin changes but effectively countered cognitive impairment and the decline in hippocampal neurogenesis in NIHL mice at 1MPN, paralleled by the normalization of microglial morphology, which coincided with a reduction in microglial myelin inclusions and a restoration of microglial hypoxia-inducible factor-1α (HIF1α) expression. Our results indicated that accelerated cognitive deterioration and hippocampal neuroplastic decline following NIHL are most likely driven by the maladaptive response of hippocampal microglia to myelin damage secondary to hearing loss, and we also demonstrated the potential of voluntary physical exercise as a promising and cost-effective strategy to alleviate the detrimental impact of APHL on cognitive function and thus curtail the high and continuously increasing global burden of dementia. Furthermore, the findings of the present study highlight the contribution of myelin debris overload to microglial malfunction and identify the microglial HIF1α-related pathway as an attractive candidate for future comprehensive investigation to obtain a more definitive picture of the underlying mechanisms linking APHL and dementia.

The development and evaluation of an online hearing loss prevention program

Recent studies underline the need for research on approaches to encouraging healthy listening habits. This study aims to develop and evaluate an online hearing loss prevention program; and examine its influence on the participants' use of hearing protection, hearing loss prevention knowledge, attitude towards noise, and program useability and adherence. The study was conducted in the county of Västra Götaland, Sweden, from March through October 2021. The program included four modules focused on hearing and hearing loss prevention and was accessible to the participants for four weeks. In total, 75 participants completed the program which was evaluated using the Youth Attitude to Noise Scale and four additional self-designed questionnaires. The questionnaires were deployed before and immediately after program completion. The findings indicate that the program may influence the participants' attitudes toward noise and the use of hearing protection. The participants who completed the program perceived high useability and increased hearing loss prevention knowledge. This program is most needed to promote healthy hearing. Future studies should target specific groups with this program and evaluate its long-term effects.

Cardiocerebrovascular risk in sensorineural hearing loss: results from the National Health and Nutrition Examination Survey 2015 to 2018

Objective

This study aims to determine whether the risks of cardiocerebrovascular disease are relevant to sensorineural hearing loss (SNHL) based on a national database.

Methods

A total of 1,321 participants aged from 18 to 69 with complete data including medical history and audiometry from the NHANES database (2015-2018) were analyzed. All included participants had available hearing data and the average thresholds of the hearing data were measured and calculated as low-frequency pure-tone average (LFPTA; 500, 1,000, and 2,000 Hz) and high-frequency pure-tone average (HFPTA; 3,000, 4,000, 6,000, and 8,000 kHz). SNHL was defined as an average pure tone of more than or equal to 20 dB in at least one better ear. Multivariable models to assess the association between cardiocerebrovascular risks and SNHL were used in this study.

Results

The prevalence of stroke was 1.6% in individuals with SNHL and 0.4% in individuals without SNHL (p = 0.023). A higher cardiovascular risk score was observed in SNHL patients compared to participants without SNHL (1.58 vs. 0.90, p < 0.001). Stroke was associated with a 3.67-fold increase in the risk of SNHL (95% CI: 1.12-12.00, p = 0.032) in univariable logistic regression, and the association (OR = 4.22, 95%CI = 1.28-13.93, p = 0.020) remained significant after adjusting for several covariates. Multivariable logistic regression models indicated a positive correlation between cardiovascular risk and SNHL (OR = 1.66, 95% CI = 1.40-1.96, p < 0.001), but no significant relationship was shown with all covariates adjusted. However, significant associations were found between SNHL and both age and sex in both univariable and multivariable logistic regression models.

Conclusion

Our findings suggested that a higher cardiocerebrovascular risk burden was associated with an increased risk of SNHL, and the relationship may be influenced by age and sex. Future longitudinal studies are needed to investigate the mechanistic and pathologic vascular hypothesis of SNHL.

Sex and Race Representation in Temporal Bone Histopathology Studies in the United States: A Systematic Review

OBJECTIVES

The author's objective was to evaluate sex and race representation in temporal bone histopathology studies.

DESIGN

PubMed, Embase, Cochrane, Web of Science, and Scopus were searched for studies written in English examining temporal bone histopathology specimens from U.S.-based institutions from January 1, 1947, to September 1, 2021. Two authors then performed "snowballing" by reviewing references from the initial search and included the studies that fulfilled the inclusion criteria. For each study, the following information was collected: publication details, study design, funding, institution from where temporal bone specimens were procured, number of study specimens, and donor demographical information.

RESULTS

The authors found that out of 300 studies, 166 (55%) report sex while only 15 (5%) reported race information. Over the past 70 years, the ratio of studies reporting sex to those that do not has increased from 1.00 to 2.19 and the number of female temporal bone histopathology subjects relative to male has increased from 0.67 to 0.75. Over 90% of studies that do report this information feature participant racial compositions that do not reflect the diversity of the U.S. population.

CONCLUSIONS

Studies of temporal bone histopathology often do not report participant sex or race. The reporting of participant sex and the inclusion of specimens from female donors have both increased over time. However, temporal bone histopathology study cohorts are not representative of the racial diversity of the U.S. population. The otolaryngology community must strive to build temporal bone histopathology libraries that are representative of the diverse U.S. population.

Sex differences and the effect of female sex hormones on auditory function: a systematic review

Aims

First, to discuss sex differences in auditory function between women and men, and whether cyclic fluctuations in levels of female sex hormones (i.e., estradiol and progesterone) affect auditory function in pre-menopausal and post-menopausal women. Second, to systematically review the literature concerning the discussed patterns in order to give an overview of the methodologies used in research. Last, to identify the gap in knowledge and to make recommendations for future work.

Methods for the systematic review

Population, Exposure, Control, Outcome and Study design (PECOS) criteria were used in developing the review questions. The review protocol follows the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was pre-registered in the Prospective Register of Systematic Reviews (PROSPERO; CRD42020201480). Data Sources: EMBASE, PubMed, MEDLINE (Ovid), PsycINFO, ComDisDome, CINAHL, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL) via Cochrane Library, and scanning reference lists of relevant studies, and internet resources (i.e., Mendeley) were used. Only studies published between 1999 and 2022, in English, or in English translation, were included. The quality of evidence was assessed using the Newcastle-Ottawa Scale (NOS).

Results

Sex differences: Women had more sensitive hearing (measured at the level of peripheral and central auditory system) than men. Cyclic fluctuations: Auditory function in women fluctuated during the menstrual cycle, while no such fluctuations in men over the same time period were reported. Hearing sensitivity improved in women during the late follicular phase, and decrease during the luteal phase, implying an effect of female sex hormones, although the specific effects of estradiol and progesterone fluctuations on the central auditory system remain unclear. Hearing sensitivity in women declined rapidly at the onset of menopause.

Conclusion

The review has shown the following. Consistent sex differences exist in auditory function across the auditory pathway with pre-menopausal women often showing better function than age-matched men. Moreover, pre-menopausal women show fluctuations in hearing function across the menstrual cycle with a better function during the peak of estradiol or when the ratio of estradiol to progesterone is high. Third, menopause marks the onset of hearing loss in women, characterized by a rapid decline in hearing sensitivity and a more pronounced loss than in age-matched men. Finally, the systematic review highlights the need for well-designed and -controlled studies to evaluate the influence of estradiol and progesterone on hearing by consistently including control groups (e.g., age-matched man), using objective tests to measure hormonal levels (e.g., in saliva or blood), and by testing participants at different points across the menstrual cycle.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020201480, identifier CRD42020201480.

Noise-induced Hearing Loss among Patients Requiring Pure Tone Audiometry Evaluation in a Tertiary Care Centre: A Descriptive Cross-sectional Study

INTRODUCTION

Noise-induced hearing loss is a type of sensorineural hearing loss caused by long-term exposure to loud noise. This study provides insight into hearing loss problems the general population faces. The study aimed to find out the prevalence of noise-induced hearing loss among patients needing pure tone audiometry evaluation in a tertiary care centre.

METHODS

A descriptive cross-sectional study was conducted from 1 January 2021 to 30 July 2021 among patients requiring pure tone audiometry evaluation in the outpatient Department of Otorhinolaryngology in a tertiary care centre. The study was conducted after ethical approval from Institutional Review Committee (Reference number: 2812202001). Pure tone audiometry was used to diagnose noise-induced hearing loss. Convenience sampling was done. Point estimate and 95% Confidence Interval were calculated.

RESULTS

Out of 690 patients, 14 (2.02%) (0.97-3.06, 95% Confidence Interval) were diagnosed with noise-induced hearing loss.

CONCLUSIONS

The prevalence of noise-induced hearing loss among patients requiring pure tone audiometry evaluation was similar to other studies conducted in similar settings.

KEYWORDS

audiometry; noise-induced hearing loss; tinnitus.

Alcohol as a risk factor for hearing loss: A systematic review and meta-analysis

OBJECTIVE

Growing evidence suggests that alcohol consumption is a risk factor for hearing loss; however, the evidence has been inconsistent. This systematic review and meta-analysis aimed to evaluate the effect of alcohol consumption on hearing loss.

METHODS

We searched several databases up to November 2021, for published articles using the keywords "alcohol drinking" and "hearing loss". Two investigators independently conducted the study selection and data extraction. Based on the results of the heterogeneity analysis (Q statistic and I2 statistic), a fixed- or random-effects model was used to calculate the pooled odds ratios (ORs). Subgroup and sensitivity analyses were performed to assess the potential sources of heterogeneity and robustness of the pooled estimation. Publication bias in the literature was evaluated using Egger's test.

RESULTS

In total, 18 (9 cross-sectional, 5 case-control, and 4 cohort) observational studies were identified in this search; 27,849 participants were included. Compared with non-drinkers, the pooled OR of drinkers was 1.22 (95% confidence interval: 1.09-1.35).

CONCLUSION

Evidence suggests a positive association between alcohol consumption and hearing loss. Drinkers were at a higher risk than non-drinkers. Drinking limitations may be useful for preventing hearing loss.

Sex-Linked Biology and Gender-Related Research Is Essential to Advancing Hearing Health

There is robust evidence that sex (biological) and gender (behavioral/social) differences influence hearing loss risk and outcomes. These differences are noted for animals and humans-in the occurrence of hearing loss, hearing loss progression, and response to interventions. Nevertheless, many studies have not reported or disaggregated data by sex or gender. This article describes the influence of sex-linked biology (specifically sex-linked hormones) and gender on hearing and hearing interventions, including the role of sex-linked biology and gender in modifying the association between risk factors and hearing loss, and the effects of hearing loss on quality of life and functioning. Most prevalence studies indicate that hearing loss begins earlier and is more common and severe among men than women. Intrinsic sex-linked biological differences in the auditory system may account, in part, for the predominance of hearing loss in males. Sex- and gender-related differences in the effects of noise exposure or cardiovascular disease on the auditory system may help explain some of these differences in the prevalence of hearing loss. Further still, differences in hearing aid use and uptake, and the effects of hearing loss on health may also vary by sex and gender. Recognizing that sex-linked biology and gender are key determinants of hearing health, the present review concludes by emphasizing the importance of a well-developed research platform that proactively measures and assesses sex- and gender-related differences in hearing, including in understudied populations. Such research focus is necessary to advance the field of hearing science and benefit all members of society.

Combined effects of multiple metals on hearing loss: A Bayesian kernel machine regression approach

BACKGROUND

Exposure to heavy elements is considered one of the risks of hearing loss. The combined effect of multiple metals on different hearing losses has not been extensively studied.

METHODS

This study deals with the association between different metals (Ba, Cd, Co, Cs, Mo, Pb, Mn, Sn, Sb, Tl, W) and hearing loss in the 2013-2018 National Health and Nutrition Examination Survey (NHANES). Associations were estimated by a generalized linear regression model (GLM) adjusting for age, gender, race/ethnicity, educational level, marital status, drinking status, hypertension, diabetes, smoking status, noise exposure, body mass index, and income-poverty ratio. The joint effects of mixed exposure were assessed by weighted quantile sum (WQS) model and Bayesian kernel machine regression (BKMR). The effect of multiple metals on speech-frequency hearing loss (SFHL) and high-frequency hearing loss (HFHL) was further calculated. The odds ratio (OR) indicates the risk of every metal exposure.

RESULTS

A total of 2205 adult participants were enrolled from NHANES. Cd, Pb, Sb and Sn had significant effects on total hearing loss. The WQS model found that mixed exposure to heavy elements was significantly positively associated with total hearing loss (OR: 1.136; 95% CI: 1.031, 1.253) after adjusting for various covariates. The ORs of mixed exposure in the SFHL and HFHL groups were 1.066 (95% CI: 0.994, 1.143) and 1.102 (95% CI: 1.013, 1.199), respectively. BKMR found a significant positive association between multiple metals and hearing loss. The results showed that there may be potential interactions between Cd, Pb and other metals.

CONCLUSIONS

Multiple metals have joint effects on hearing loss in the United States. The findings provide practitioners with important scientific evidence for possible interventions.

Should data on gender and ethnicity inform ergonomics interventions? Lessons from four case studies

Ergonomists intervene to improve work for all workers and adapt jobs to a range of worker characteristics. But their mandate rarely includes explicit attention to the distribution of worker demographics, to divisions among workers, or to discrimination on the basis of sex/gender or racialisation. A decades-long collaboration between ergonomists and the women's committees of three union confederations in Québec, Canada led to several instances where ergonomists had to confront situations involving sexism or racism, not foreseen during their training. This article will explore four problematic situations and suggest solutions, including paying more attention to teamwork, considering gender during ergonomics training, and developing a code of practice for ergonomics interventions.Practitioner summary: Workplace inequities related to sex/gender, racialisation and other sources of social inequity can affect job performance and workers' health. As such, do ergonomists need to consider them during an intervention? How? We analyse four situations encountered during interventions and suggest more attention to understanding workplace dynamics and promoting team function.

Galectin-3 protects auditory function in female mice

Sex differences in the development of sensorineural hearing loss have been recognized in various inner ear disorders, but the molecular basis for such differences is poorly understood. Autosomal genes have been shown to cause sex differences in disease susceptibility, but many genes exerting sex-dependent effects on auditory function remain to be identified. Galectin-3 (Gal-3), a protein encoded by the autosomal gene Lgals3, is a member of the β-galactoside-binding protein family, and has been linked to multiple biological processes, including immune responses, apoptosis, and cell adhesion. Here, we investigated auditory function and hair cell integrity in Gal-3 knockout (KO, Lgals3^-/-) and wild-type (WT, Lgals3^+/+) mice from age 1 to 6 months. KO mice show a more rapid age-related increase in ABR thresholds compared to WT mice. Noticeably, the threshold deterioration in female KO mice is significantly greater than in the male KO and WT mice. The ABR threshold elevation manifests over a broad frequency range in female KO mice, whereas the threshold elevations are confined to high frequencies in the male KO and WT mice. Moreover, DPOAE input/output functions reveal a similar pattern of auditory dysfunction, with the female KO mice displaying a significantly greater reduction in DPOAE amplitudes than male KO mice and WT mice of both sexes. Finally, age-related outer hair cell loss is greater for female KO mice compared to male KO mice and WT mice of both sexes. Together, these results indicate that Gal-3 deficiency exacerbates age-related cochlear degeneration and auditory dysfunction in female mice. Our study identifies Gal-3 as a sex-dependent molecule for maintaining female cochlear integrity.

Development and initial validation of the Chinese Version of the Noise Exposure Questionnaire (C-NEQ)

BACKGROUND

With a high prevalence of noise-induced hearing loss (NIHL), the noise survey tools for identifying individuals with high risk of NIHL are still limited. This study was aimed to translate and develop a Chinese version of noise exposure questionnaire (C-NEQ), and validate its reliability and reproducibility.

METHODS

This study was conducted from May 2020 to March 2021 in China. The questionnaire was translated from the original NEQ and adapted into Chinese culture using the method according to the International Test Committee. Content validity was evaluated by our expert group. Construct validity and reliability of the C-NEQ was determined through estimating the confirmatory factor analysis and Cronbach's alpha in a cross-sectional analysis among 641 Chinese speaking adults, respectively. The retest reproducibility of the C-NEQ was analyzed by using the intra-group correlation coefficient (ICC) in a follow-up analysis among 151 participants.

RESULTS

The C-NEQ comprises ten items covering four domains: occupational, housework, transport and recreational noise exposure. The annual noise exposure (ANE) was calculated as the protocol of original NEQ. A total of 641 adult participants (aged 26.9 ± 10.1 years, 53.4% males) completed the C-NEQ. The average time for completing the C-NEQ was 4.4 ± 3.0 min. Content validity indicated high relevance of the C-NEQ. The confirmatory factor analysis indices illustrated that the items of the C-NEQ were suitable with the data in the study. For the internal reliability, the Cronbach's α coefficients of the total items and four domains (occupational, housework, transport, and recreational noise exposure) were 0.799, 0.959, 0.837, 0.825, and 0.803, respectively. Among them, 151 participants (aged 36.1 ± 11.1 years, 65.6% males) completed the retest of the C-NEQ 1 month after the first test. The ICC value of total ANEs between the first test and the second test was 0.911 (P < 0.001).

CONCLUSIONS

In this study, we have validated the C-NEQ with adequate reliability and reproducibility for quantifying an individual's annual daily noise exposure, which provides an effective fast-screen tool for researches and clinics to identify those individuals with high risks of NIHL within the short time duration (no more than five minutes) among Chinese population.

Sex Differences in the Triad of Acquired Sensorineural Hearing Loss

The triad of noise-generated, drug-induced, and age-related hearing loss is the major cause of acquired sensorineural hearing loss (ASNHL) in modern society. Although these three forms of hearing loss display similar underlying mechanisms, detailed studies have revealed the presence of sex differences in the auditory system both in human and animal models of ASNHL. However, the sexual dimorphism of hearing varies among noise-induced hearing loss (NIHL), ototoxicity, and age-related hearing loss (ARHL). Importantly, estrogen may play an essential role in modulating the pathophysiological mechanisms in the cochlea and several reports have shown that the effects of hormone replacement therapy on hearing loss are complex. This review will summarize the clinical features of sex differences in ASNHL, compare the animal investigations of cochlear sexual dimorphism in response to the three insults, and address how estrogen affects the auditory organ at molecular levels.

Dose-Dependent Pattern of Cochlear Synaptic Degeneration in C57BL/6J Mice Induced by Repeated Noise Exposure

It is widely accepted that even a single acute noise exposure at moderate intensity that induces temporary threshold shift (TTS) can result in permanent loss of ribbon synapses between inner hair cells and afferents. However, effects of repeated or chronic noise exposures on the cochlear synapses especially medial olivocochlear (MOC) efferent synapses remain elusive. Based on a weeklong repeated exposure model of bandwidth noise over 2-20 kHz for 2 hours at seven intensities (88 to 106 dB SPL with 3 dB increment per gradient) on C57BL/6J mice, we attempted to explore the dose-response mechanism of prolonged noise-induced audiological dysfunction and cochlear synaptic degeneration. In our results, mice repeatedly exposed to relatively low-intensity noise (88, 91, and 94 dB SPL) showed few changes on auditory brainstem response (ABR), ribbon synapses, or MOC efferent synapses. Notably, repeated moderate-intensity noise exposures (97 and 100 dB SPL) not only caused hearing threshold shifts and the inner hair cell ribbon synaptopathy but also impaired MOC efferent synapses, which might contribute to complex patterns of damages on cochlear function and morphology. However, repeated high-intensity (103 and 106 dB SPL) noise exposures induced PTSs mainly accompanied by damages on cochlear amplifier function of outer hair cells and the inner hair cell ribbon synaptopathy, rather than the MOC efferent synaptic degeneration. Moreover, we observed a frequency-dependent vulnerability of the repeated acoustic trauma-induced cochlear synaptic degeneration. This study provides a sight into the hypothesis that noise-induced cochlear synaptic degeneration involves both afferent (ribbon synapses) and efferent (MOC terminals) pathology. The pattern of dose-dependent pathological changes induced by repeated noise exposure at various intensities provides a possible explanation for the complicated cochlear synaptic degeneration in humans. The underlying mechanisms remain to be studied in the future.

A risk model and nomogram for high-frequency hearing loss in noise-exposed workers

Background

High-frequency hearing loss is a significant occupational health concern in many countries, and early identification can be effective for preventing hearing loss. The study aims to construct and validate a risk model for HFHL, and develop a nomogram for predicting the individual risk in noise-exposed workers.

Methods

The current research used archival data from the National Key Occupational Diseases Survey-Sichuan conducted in China from 2014 to 2017. A total of 32,121 noise-exposed workers completed the survey, of whom 80% workers (n = 25,732) comprised the training cohort for risk model development and 20% workers (n = 6389) constituted the validation cohort for model validation. The risk model and nomogram were constructed using binary logistic models. The effectiveness and calibration of the model were evaluated with the receiver operating characteristic curve and calibration plots, respectively.

Results

A total of 10.06% of noise-exposed workers had HFHL. Age (OR = 1.09, 95% CI: 1.083–1.104), male sex (OR = 3.25, 95% CI: 2.85–3.702), noise exposure duration (NED) (OR = 1.15, 95% CI: 1.093–1.201), and a history of working in manufacturing (OR = 1.50, 95% CI: 1.314–1.713), construction (OR = 2.29, 95% CI: 1.531–3.421), mining (OR = 2.63, 95% CI: 2.238–3.081), or for a private-owned enterprise (POE) (OR = 1.33, 95% CI: 1.202–1.476) were associated with an increased risk of HFHL (P < 0.05).

Conclusions

The risk model and nomogram for HFHL can be used in application-oriented research on the prevention and management of HFHL in workplaces with high levels of noise exposure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10730-y.

Acute Recreational Noise-Induced Cochlear Synaptic Dysfunction in Humans With Normal Hearing: A Prospective Cohort Study

Objectives

The objective of the study was to identify the acute high-intensity recreational noise-induced effects on auditory function, especially the cochlear synaptopathy-related audiological metrics, in humans with normal hearing.

Methods

This prospective cohort study enrolled 32 young adults (14 males and 18 females); the mean age was 24.1 ± 2.4 years (ranging from 20 to 29). All participants with normal hearing (audiometric thresholds ≤25 dB HL at frequencies of 0.25, 0.5, 1, 2, 3, 4, 6, and 8 kHz for both ears) had already decided to participate in the outdoor music festival. Participants were asked to measure the noise exposure dose and complete auditory examinations, including the air-conduction pure-tone audiometry (PTA), distortion product otoacoustic emission (DPOAE), contralateral suppression (CS) on transient evoked otoacoustic emission (TEOAE), auditory brainstem response (ABR) test and Mandarin Hearing in Noise Test (MHINT), at baseline and 1 day and 14 days after music festival noise exposure.

Results

The mean time of attending the music festival was 7.34 ± 0.63 h (ranging from 6.4 to 9.5), the mean time-weighted average (TWA) of noise exposure dose was 93.2 ± 2.39 dB(A) (ranging from 87.9 to 97.7). At neither 1 day nor 14 days post exposure, there were no statistically significant effects on PTA thresholds, DPOAE amplitudes, CS on TEOAEs, or MHINT signal-to-noise ratios (SNRs) of acute outdoor music festival noise exposure, regardless of sex. While the ABR wave I amplitudes significantly decreased at 1 day after exposure and recovered at 14 days after exposure, the exposed/unexposed ABR wave I amplitude ratio was significantly correlated with MHINT SNR change at 1 day after exposure, although it was not correlated with the noise exposure dose.

Conclusion

In young adults with normal hearing, we found the self-compared decrement of ABR wave I amplitudes at 1 day post acute recreational noise exposure at high intensity, which also contributes to the change in speech perceptual ability in noisy backgrounds. This study indicated that auditory electrophysiological metric changes might be a more sensitive and efficient indicator of noise-induced cochlear synaptic dysfunction in humans. More attention should be paid to the recreational noise-induced cochlear synaptopathy and auditory perceptual disorder.