Prevalence of loud leisure noise activities among a representative sample of Canadians aged 6-79 years

Ten-year results of leisure noise exposure among adolescents and young adults-findings from the OHRKAN cohort study

OBJECTIVE

To observe total leisure noise (TLN) exposure and to investigate determinants of risky TLN exposure among adolescents and young adults over a ten-year observation period.

DESIGN

OHRKAN is a longitudinal study with five equidistantly distributed questionnaires (waves) over ten years. Risky TLN exposure was defined as exceeding ≥85dB(A) averaged over 40h per week. To identify determinants of risky TLN exposure longitudinally, generalised estimating equations were applied.

STUDY SAMPLE

A subgroup (n = 661; mean age 25.6 years in the fifth wave; 58.4% female) of the closed cohort study OHRKAN was analysed. Included participants took part in the fifth wave prior to the study break due to COVID-19.

RESULTS

Analysis of participants' data from all five waves showed that risky TLN exposure was highest during the second wave (72.0%), when participants were aged 17-19 years, and thereafter steadily declined. Among young adults, attendance at discotheques and private parties, especially, caused very high exposure. Determinants of risky TLN exposure were wave time point, male gender, a higher level of education, and smoking.

CONCLUSIONS

As TLN exposure is highest among older adolescents, prevention programs should target younger teenagers and be tailored to the identified risk groups. The risk from private parties should be addressed.

Leisure noise exposure and hearing outcomes among Canadians aged 6 to 79 years

OBJECTIVE

To examine the association between individual and cumulative leisure noise exposure in addition to acceptable yearly exposure (AYE) and hearing outcomes among a nationally representative sample of Canadians.

DESIGN

Audiometry, distortion-product otoacoustic emissions (DPOAEs) and in-person questionnaires were used to evaluate hearing and leisure noise exposure across age, sex, and household income/education level. High-risk cumulative leisure noise exposure was defined as 85 dBA or greater for 40 h or more per week, with AYE calculations also based on this occupational limit.

STUDY SAMPLE

A randomised sample of 10,460 respondents, aged 6-79, completed questionnaires and hearing evaluations between 2012 and 2015.

RESULTS

Among 50-79 year olds, high-risk cumulative leisure noise was associated with increased odds of a notch while high exposure to farming/construction equipment noise was associated with hearing loss, notches and absent DPOAEs. No associations with hearing loss were found however, non-significant tendencies observed included higher mean hearing thresholds, notches and hearing loss odds.

CONCLUSION

Educational outreach and monitoring of hearing among young and middle-aged populations exposed to hazardous leisure noise would be beneficial.

Attitudes to noise in young adults and associated factors: adaptation of the youth attitude to noise scale into Spanish using item response theory analysis

OBJECTIVE

This study aimed to identify the attitudes to noise in young adults and the possible effects of gender, age, and a positive history of auditory symptoms related to recreational noise exposure on the attitudes to noise in this population.

DESIGN

The Youth Attitude to Noise (YANS) and the hearing symptom description (HSD) scales were adapted into Spanish to be used with young adults. The validity was determined using factor analyses and Item Response Theory (IRT) models. Linear regression models were used to determine whether the YANS scores were associated with gender, age, and auditory symptoms.

STUDY SAMPLE

Both instruments were given to a sample of 728 Chilean young adults. Data obtained from this sample was used to determine the YANS and HSD scales' validity and to assess the effects of gender, age, and auditory symptoms on attitudes.

RESULTS

Our results showed that the YANS and HSD scales had adequate validity and reliability. Differences in the items' capacity to discriminate attitudes to noise were noted using the IRT model. Auditory symptoms were significantly associated with the YANS scores.

CONCLUSIONS

The attitudes to noise in Chilean young adults are influenced by self-perception of auditory symptoms, age, and gender.

Hair cortisol as a viable tool for the assessment of an association between environmental noise exposure and chronic stress

Entrenched in the well-established link between stress and health, noise exposure as a potential contributor to stress-related health effects receives tremendous attention. Indeed, exposure to noise can act as a stressor as evidenced through increased heart rate, blood pressure, adrenaline, epinephrine, and cortisol. Cortisol is secreted from the adrenal glands in response to stressor-induced activation of the hypothalamic-pituitary-adrenal axis. For assessment of environmental noise and stress, repeated sampling in blood, saliva, or urine is necessary to evaluate the association between environmental noise exposure and protracted changes in cortisol. Controlling for the many variables that influence the secretion of cortisol at discrete sampling intervals is challenging. Studies suggest that systemically produced cortisol integrates and remains in hair as it grows, providing a measure that integrates a cortisol response over a longer period, circumventing several limitations associated with multiple sampling. Robust evidence supports the integration of cortisol into hair, yet recent studies call into question the notion that cortisol is retained with growth. The current paper discusses the strengths and limitations of hair cortisol analysis with an emphasis on its utility as a measure of chronic stress in environmental noise studies.

Hearing loss drug discovery and medicinal chemistry: Current status, challenges, and opportunities

Hearing loss is a severe high unmet need condition affecting more than 1.5 billion people globally. There are no licensed medicines for the prevention, treatment or restoration of hearing. Prosthetic devices, such as hearing aids and cochlear implants, do not restore natural hearing and users struggle with speech in the presence of background noise. Hearing loss drug discovery is immature, and small molecule approaches include repurposing existing drugs, combination therapeutics, late-stage discovery optimisation of known chemotypes for identified molecular targets of interest, phenotypic tissue screening and high-throughput cell-based screening. Hearing loss drug discovery requires the integration of specialist therapeutic area biology and otology clinical expertise. Small molecule drug discovery projects in the global clinical portfolio for hearing loss are here collated and reviewed. An overview is provided of human hearing, inner ear anatomy, inner ear delivery, types of hearing loss and hearing measurement. Small molecule experimental drugs in clinical development for hearing loss are reviewed, including their underpinning biology, discovery strategy and activities, medicinal chemistry, calculated physicochemical properties, pharmacokinetics and clinical trial status. SwissADME BOILED-Egg permeability modelling is applied to the molecules reviewed, and these results are considered. Non-small molecule hearing loss assets in clinical development are briefly noted in this review. Future opportunities in hearing loss drug discovery for human genomics and targeted protein degradation are highlighted.

The association of sociodemographic factors and risk behavior with unsafe use of personal listening devices in adolescents

Many young people are potentially at risk of noise-induced hearing loss due to unsafe use of personal listening devices. The aim of this cross-sectional study was to examine the association of sociodemographic factors and risk behavior with unsafe use of personal listening devices in adolescents to identify a target group for prevention. A smartphone application was developed to objectively measure music listening habits among 314 adolescents with a mean age of 13 years and 7 months (SD ±5 months). Listening habits were characterized as safe or unsafe based on the weekly noise dose. Data on sociodemographic factors and traditional health risk behaviors were obtained by questionnaires. Within the study group, 10.5% of the participants exceeded the 50%, and 4.8% the 100% recommended weekly noise dose. Adolescents with a lower socioeconomic status were more likely to engage in unsafe listening habits as compared to adolescents with a higher socioeconomic status. Additionally, risk behavior was associated with higher odds of having unsafe listening habits as compared to no risk behavior. Age, sex and educational levels were not significantly associated with unsafe listening habits. The findings of the present study indicate that interventions to promote safe listening habits should target adolescents with a lower socioeconomic status and higher risk behavior. Future research is needed to investigate how these adolescents can be motivated to adopt safe listening habits.

Stress Response and Hearing Loss Differentially Contribute to Dynamic Alterations in Hippocampal Neurogenesis and Microglial Reactivity in Mice Exposed to Acute Noise Exposure

Noise-induced hearing loss (NIHL) is one of the most prevalent forms of acquired hearing loss, and it is associated with aberrant microglial status and reduced hippocampal neurogenesis; however, the nature of these associations is far from being elucidated. Beyond its direct effects on the auditory system, exposure to intense noise has previously been shown to acutely activate the stress response, which has increasingly been linked to both microglial activity and adult hippocampal neurogenesis in recent years. Given the pervasiveness of noise pollution in modern society and the important implications of either microglial activity or hippocampal neurogenesis for cognitive and emotional function, this study was designed to investigate how microglial status and hippocampal neurogenesis change over time following acoustic exposure and to analyze the possible roles of the noise exposure-induced stress response and hearing loss in these changes. To accomplish this, adult male C57BL/6J mice were randomly assigned to either a control or noise exposure (NE) group. Auditory function was assessed by measuring ABR thresholds at 20 days post noise exposure. The time-course profile of serum corticosterone levels, microglial status, and hippocampal neurogenesis during the 28 days following noise exposure were quantified by ELISA or immunofluorescence staining. Our results illustrated a permanent moderate-to-severe degree of hearing loss, an early but transient increase in serum corticosterone levels, and time-dependent dynamic alterations in microglial activation status and hippocampal neurogenesis, which both present an early but transient change and a late but enduring change. These findings provide evidence that both the stress response and hearing loss contribute to the dynamic alterations of microglia and hippocampal neurogenesis following noise exposure; moreover, noise-induced permanent hearing loss rather than noise-induced transient stress is more likely to be responsible for perpetuating the neurodegenerative process associated with many neurological diseases.

Identifying Targets for Interventions to Increase Earplug Use in Noisy Recreational Settings: A Qualitative Interview Study

Earplugs can reduce the risk of hearing loss and tinnitus. However, earplug use during noisy recreational activities is uncommon, and methods for increasing uptake and regular use have had limited efficacy. The aim of the present study was to examine barriers and enablers of ever-performers (e.g., people who have used earplugs) and never-performers (e.g., people who have not used earplugs) to identify targets to inform the content of interventions to increase uptake and regular use of earplugs in recreational settings. The Capabilities, Opportunities, and Motivations model of Behaviour (COM-B) informed the outline for 20 semi-structured telephone interviews (ever-performers, N = 8, age range = 20-45 years; never-performers, N = 12; age range = 20-50 years). Thematic analysis was used to identify barriers and enablers to earplug use, which were mapped onto the Theoretical Domains Framework (TDF). Six key domains of the TDF were identified. Ever-performers described being more exposed to 'social influences' (e.g., facilitators such as friends/peers) and were more positive than never-performers concerning 'beliefs about consequences' (e.g., earplug protection outweighs any negative effects on listening/communication). Involvement of 'emotion' (e.g., fear of losing ability to listen to music) and 'reinforcement' tactics (e.g., creating habits/routines) were discussed by ever-performers, but were not mentioned by never-performers. Both groups reported lack of 'environmental context and resources' (e.g., prompts and cues), and their own 'memory, attention, and decision processes' (e.g., deciding when to use earplugs) as barriers to earplug use. The present research identifies the variables that would need to change in order to increase earplug uptake and use in recreational settings among ever-performers and never-performers. Further work is required to translate these findings into testable interventions by selecting appropriate intervention functions (e.g., modelling), policy categories (e.g., communication/marketing), behaviour change techniques (e.g., demonstration of behaviour), and mode of delivery (e.g., face-to-face).

High frequency hearing impairment and cardiovascular disease in Canada: Results from the Canadian Health Measures Survey

Noise-induced stress may precipitate cardiovascular diseases. This research assessed the association between sensorineural bilateral high frequency hearing loss (HFHL), as an indication of excessive noise exposure, and cardiovascular outcomes. Participants (n = 6318, ∼50% male) 20-79 years were recruited through the cross-sectional Canadian Health Measures Survey. Questionnaires included several demographic and health-related variables. Audiometry and blood/urine collection took place in a mobile examination centre. Average thresholds ≥25 dB averaged across 3, 4, and 6 kHz defined HFHL. Logistic or linear regression models explored associations between HFHL and cardiovascular-related risk factors/outcomes. Adjusted models indicated elevated diastolic blood pressure in respondents with normal hearing, X¯ = 72.52 (95% confidence interval: 71.85-73.18) compared to the group with bilateral HFHL, X¯ = 70.28 (95%CI: 69.13-71.43), p < 0.05. Average total cholesterol, high-density lipoprotein, low-density lipoprotein and apolipoprotein A1 were elevated in the normal hearing group (p < 0.05). Insulin, high-sensitivity C-reactive protein, and average resting heart rate were elevated in the group with bilateral HFHL, p < 0.05. A stratified analysis by sex- and age, or history of loud occupational noise exposure, did not change the overall results. Although some findings warrant further exploration, the overall analysis did not provide compelling evidence for an association between HFHL and cardiovascular-related biomarkers, or cardiovascular diseases among Canadians aged 20-79 years.

Self-reported occupational noise exposure and cardiovascular disease in Canada: Results from the Canadian Health Measures Survey

Self-reported occupational noise exposure has been associated with impaired hearing, but its relationship with extra-auditory affects remains uncertain. This research assessed the association between self-reported occupational noise exposure and cardiovascular outcomes. Participants (n = 6318, ∼50% male) from the Canadian Health Measures Survey (2012-2015) aged 20-79 years were randomly recruited across Canada. An in-person household interview included basic demographics, perceived stress, diagnosed health conditions, and self-reported exposure to a noisy work environment. Direct physiological assessment in a mobile examination centre permitted the determination of biomarkers/risk factors related to cardiovascular function. Logistic or linear regression models explored the association between self-reported occupational noise exposure and several cardiovascular endpoints after adjusting for confounding variables. After adjustments, there was no evidence for an association between occupational noise and any of the evaluated endpoints, which included but were not limited to blood pressure, heart rate, blood glucose, insulin, lipids, diagnosed hypertension, medication for hypertension, myocardial infarction, stroke, or heart disease. There was no evidence that self-reported occupational noise exposure was associated with evaluated cardiovascular-related biomarkers, or cardiovascular diseases among Canadians aged 20-79 years. This study, and others like it, provides an important contribution to an evidence base that could inform policy related to occupational noise exposure.

Loud Music and Leisure Noise Is a Common Cause of Chronic Hearing Loss, Tinnitus and Hyperacusis

High sound levels capable of permanently damaging the ear are experienced not only in factories and war zones but in concert halls, nightclubs, sports stadiums, and many other leisure environments. This review summarizes evidence that loud music and other forms of "leisure noise" are common causes of noise-induced hearing loss, tinnitus, and hyperacusis, even if audiometric thresholds initially remain within clinically normal limits. Given the huge global burden of preventable noise-induced hearing loss, noise limits should be adopted in a much broader range of settings, and education to promote hearing conservation should be a higher public health priority.

Personal listening device usage among Canadians and audiometric outcomes among 6-29 year olds

OBJECTIVE

To describe personal listening device (PLD) usage and sociodemographic variables among a nationally representative sample of Canadians and examine audiometric outcomes among a subsample.

DESIGN

Audiometry and in-person questionnaires were used to evaluate hearing and PLD usage across age, sex, household income/education level. PLD exposure was quantified using a common occupational noise limit.

STUDY SAMPLE

A randomised sample of 10,460 respondents, aged 6-79, with audiometric analysis of a subsample (n = 4807), aged 6-29, tested between 2012 and 2015.

RESULTS

Loud PLD usage was reported by19.5% of Canadians. The highest prevalence was among teenagers (44.2%) and young adults (36.3%). Among children, 13.1% of users listened at loud volumes. High PLD usage (equivalent to or above 85 dBA, LEX 40) among 12-19 year olds was double that of 20-29 year olds: 10.2% versus 5.1%^E. Five years or more of loud PLD usage was associated with significantly higher mean hearing thresholds compared to less years. No association between loud or high PLD usage and mean thresholds were found.

CONCLUSION

The majority used PLDs safely, however a small proportion reported high risk usage which will impact hearing should this pattern persist over many years.

Noise-induced hearing loss and its prevention: Integration of data from animal models and human clinical trials

Animal models have been used to gain insight into the risk of noise-induced hearing loss (NIHL) and its potential prevention using investigational new drug agents. A number of compounds have yielded benefit in pre-clinical (animal) models. However, the acute traumatic injury models commonly used in pre-clinical testing are fundamentally different from the chronic and repeated exposures experienced by many human populations. Diverse populations that are potentially at risk and could be considered for enrollment in clinical studies include service members, workers exposed to occupational noise, musicians and other performing artists, and children and young adults exposed to non-occupational (including recreational) noise. Both animal models and clinical populations were discussed in this special issue, followed by discussion of individual variation in vulnerability to NIHL. In this final contribution, study design considerations for NIHL otoprotection in pre-clinical and clinical testing are integrated and broadly discussed with evidence-based guidance offered where possible, drawing on the contributions to this special issue as well as other existing literature. The overarching goals of this final paper are to (1) review and summarize key information across contributions and (2) synthesize information to facilitate successful translation of otoprotective drugs from animal models into human application.

Noise-induced hearing loss: Translating risk from animal models to real-world environments

Noise-induced hearing loss (NIHL) is a common injury for service members and civilians. Effective prevention of NIHL with drug agents would reduce the prevalence of NIHL. There are a host of challenges in translation of investigational new drug agents from animals into human clinical testing, however. Initial articles in this special issue describe common pre-clinical (animal) testing paradigms used to assess potential otoprotective drug agents and design-related factors that impact translation of promising agents into human clinical trials. Additional articles describe populations in which NIHL has a high incidence and factors that affect individual vulnerability. While otoprotective drugs will ultimately be developed for use by specific noise-exposed populations, there has been little effort to develop pre-clinical (animal) models that accurately model exposure hazards across diverse human populations. To facilitate advances in the translational framework for NIHL otoprotection in pre-clinical and clinical testing, the overarching goals of the current series are to (1) review the animal models that have been used, highlighting the relevance to the human populations of interest, (2) provide insight into the populations for whom pharmaceutical interventions might, or might not, be appropriate, and (3) highlight the factors that drive the significant individual variability observed in humans.