Hearing loss associated with smoking and occupational noise exposure in a Japanese metal working company

MANSHIP: Mobile-based assistive notification service for hearing-impaired people using a hybrid deep learning model

Hearing impairment, often caused by noise-induced trauma, significantly affects sound perception, communication, and cognitive abilities while increasing the risk of secondary accidents-individuals with hearing impairment are twice as likely to experience accidents as those with normal hearing. According to a 2023 WHO report, approximately 432 million adults and 34 million children globally are affected by hearing loss. While Assistive Listening Devices are commonly recommended, they are inadequate for individuals with total hearing loss. Therefore, alternatives are necessary to enhance safety and reduce accident risks. The present study introduces a hybrid deep learning model combining Very Deep Convolutional Networks (VGG16) and Residual Networks (ResNet-50) for efficient sound wave analysis and classification. Trained and validated on a comprehensive urban sound dataset, the model achieved a remarkable accuracy of 97.14%, surpassing existing state-of-the-art solutions. Furthermore, a mobile-based assistive notification system, MANSHIP, was developed to detect environmental sounds and alert individuals with profound or total hearing loss to potential hazards. MANSHIP addresses critical safety challenges and demonstrates the potential to improve the quality of life for those with severe hearing impairments by fostering safer environments and reducing caregiver dependency.

The Burden of Occupational Noise-Induced Hearing Loss From 1990 to 2019: An Analysis of Global Burden of Disease Data

OBJECTIVES

The relationship between long-term exposure to occupational noise and hearing loss has been extensively documented. We aimed to assess spatial and temporal changes in the burden of occupational noise-induced hearing loss (ONIHL) in 204 countries and territories with varying socio-demographic indexes (SDI) from 1990 to 2019.

DESIGN

Temporal and spatial trends in age-standardized disability-adjusted life year rates (ASDR) for ONIHL were estimated by sex, age, SDI level, country, and geographic region from 1990 to 2019. We used the Joinpoint model to calculate annual average percentage changes to assess such trends and projected trends in ASDR for ONIHL globally and across different income regions from 2020 to 2044 using an age-period-cohort model. We fitted the relationship between ASDR and SDI, ASDR and healthcare access and quality index, respectively.

RESULTS

Overall, the global burden of ONIHL has decreased since 1990, especially in middle and lower SDI regions. In 2019, the global ASDR for ONIHL was 84.23 (95% confidence interval: 57.46 to 120.52) per 100,000 population. From 1990 to 2019, the global ASDR for ONIHL decreased by 1.72% (annual average percentage change = -0.05, 95% confidence interval: -0.07 to -0.03). Our projections showed a decreasing trend in the global ONIHL burden until 2044. ASDR and SDI ( R = -0.8, p < 0.05), ASDR and healthcare access and quality index ( R = -0.75, p < 0.05) showed significant negative correlations.

CONCLUSIONS

The global ONIHL burden has decreased over the past three decades, especially in regions with middle and lower SDI levels. However, the global ONIHL burden still remained severe in 2019, notably among males, the middle-aged and elderly, and regions with lower SDI levels.

Relationship between tinnitus and olfactory dysfunction: audiovisual, olfactory, and medical examinations

Introduction

Sensory dysfunctions and cognitive impairments are related to each other. Although a relationship between tinnitus and subjective olfactory dysfunction has been reported, there have been no reports investigating the relationship between tinnitus and olfactory test results.

Methods

To investigate the relationship between tinnitus and olfactory test results, we conducted sensory tests, including hearing and visual examinations. The subjects included 510 community-dwelling individuals (295 women and 215 men) who attended a health checkup in Yakumo, Japan. The age of the subjects ranged from 40 to 91 years (mean ± standard deviation, 63.8 ± 9.9 years). The participants completed a self-reported questionnaire on subjective tinnitus, olfactory function, and hearing function, as well as their lifestyle. The health checkup included smell, hearing, vision, and blood examinations.

Results

After adjusting for age and sex, the presence of tinnitus was significantly associated with subjective olfactory dysfunction, poor olfactory test results, hearing deterioration, vertigo, and headache. Additionally, high serum calcium levels and a low albumin/globulin ratio were significantly associated with low physical activity and nutrition. Women scored higher than men in olfactory and hearing examinations, but there was no gender difference in vision examinations.

Conclusion

Subjective smell dysfunction and poor smell test results were significantly associated with tinnitus complaints. Hearing and vision were associated even after adjusting for age and sex. These findings suggest that evaluating the mutual relationships among sensory organs is important when evaluating the influence of sensory dysfunctions on cognitive function.

Association of dietary factors with noise-induced hearing loss in Korean population: A 3-year national cohort study

Noise-induced hearing loss (NIHL) is a hearing impairment (HI) caused by various clinical factors. Identifying the relationship between NIHL and nutrient consumption could help in reducing the prevalence of hearing loss. The aim of this study was to analyze the relationship between NIHL and dietary factors using data of the Korea National Health and Nutrition Examination survey (KNHANES). The data were collected from The Fifth KNHANES 2010-2012. The survey was taken by a total of 10,850 participants aged 20-65 years. Air conduction audiometry was measured at 500, 1000, 2000, and 4000 Hz in both ears. Metabolic syndrome, noise exposure, alcohol consumption, smoking, income level, marital status, and nutritional intake were evaluated. The differences between non-HI and HI participants in the noise-exposed group showed statistically significant differences in age, sex, marital and smoking status, alcohol consumption, and fasting glucose and triglyceride levels (p<0.05). In a multiple regression analysis of the noise-exposed group, age showed a significant association with HI (OR: 0.604; 95% CI: 0.538-0.678) after adjusting for confounders. In multivariate analysis for dietary factors affecting HI in noise-exposed groups, retinol (OR: 1.356; 95% CI: 1.068-1.722), niacin (OR: 1.5; 95% CI: 1.022-2.201), and carbohydrates (OR: 0.692; 95% CI: 0.486-0.985) showed a significant association with NIHL. Age was identified as the only factor significantly affecting NIHL. When the dietary factors of the noise-exposed group were analyzed, high intake of niacin and retinol and low intake of carbohydrates appeared to reduce the risk of hearing loss.

Hearing loss and its associated factors among metal workshop workers at Gondar city, Northwest Ethiopia

Introduction

Noise-induced hearing loss is a permanent sensorineural deficiency, which is caused by exposure to excessive noise sound. Although noise-induced hearing loss due to industrialization is a main public health problem in Ethiopia, studies on the prevalence and associated factors of hearing loss are scarce.

Objectives

This study aimed to assess the prevalence and associated factors of hearing loss among workers at a metal workshop in Gondar city, Northwest Ethiopia.

Methods

A cross-sectional study was employed among 300 participants using a stratified sampling technique. Data were collected using an interviewer-administered questionnaire. Bivariable and multivariable logistic regressions were conducted. In the multivariable logistic regression model, adjusted odds ratios (AOR) with a 95% confidence interval (CI) and a p &lt; 0.05 were computed to determine the level of significance.

Results

The prevalence of hearing loss among metal workshop workers was 30.7% [95% CI: (25.7, 35.7)]. Age between 30 and 44 years [AOR = 2.9; 95% CI: 1.2, 7.1], age between 45 and 65 years [AOR = 3.8; 95% CI (1.5, 9.5)], cigarette smoking [AOR = 2.3; 95% CI: 1.2, 4.5], working area noise level &gt;85 dB [AOR = 2.2; 95% CI: 1.1, 6.5], working experience of 6–10 years [AOR = 1.8; 95% CI: 1.4, 6.0], working experience &gt;10 years [AOR = 3.5; 95% CI: 1.3, 4.3], and using ear protection devices [AOR = 0.3; 95% CI: 0.1, 0.6] were significantly associated with hearing loss.

Conclusion

The prevalence of hearing loss was considerably high. This study revealed that advanced age, cigarette smoking, increased working area noise level, and working experiences were found to increase the odds of having hearing loss. Therefore, it is important to emphasize metal workshop workers that are at high risk of hearing loss and develop preventive strategies to reduce the burden of this problem. Besides, minimizing working area noise levels, proper utilization of ear protection devices, and creating awareness about the impact of hearing loss are recommended.

Association between Smoking and Noise-Induced Hearing Loss: A Meta-Analysis of Observational Studies

The purpose of this study was to synthesize the results of previously published observational studies through meta-analysis to clarify the association between smoking and noise-induced hearing loss (NIHL). We searched several databases as of October 2019. Based on the results of heterogeneity analysis (Q statistic and I² statistic), a fixed effect model (for no heterogeneity; Q test P > 0.1 and I² ≤ 50%) or a random effects model (for heterogeneity) was used to calculate the pooled odds ratios (ORs). We explored the potential dose-response relationship between smoking and NIHL as well. In total, 27 studies involving 30,465 participants were included. Compared with non-smokers, the pooled OR of current smokers was 2.05 (95% Confidence interval (CI): 1.71–2.46), and of former smokers was 1.11 (95% CI: 1.05–1.18). We found a curve linear association between an increasing number of pack-years (packages/day × smoking years) and risk of NIHL. The dose-response meta-analysis suggested that when the number of pack-years was less than fifteen, the risk of NIHL was increasing, and the highest combined OR was 5.25 (95% CI: 2.30–11.96) for pack-years of fifteen. After fifteen pack-years, the pooled OR had a slow decline. Our study indicated that smoking is a risk factor for NIHL. Current smokers have a higher risk than former smokers, and there is a positive dose-response relationship between smoking and NIHL.

Relationship between Inflammatory Food Consumption and Age-Related Hearing Loss in a Prospective Observational Cohort: Results from the Salus in Apulia Study

Age related hearing loss (ARHL) affects about one third of the elderly population. It is suggested that the senescence of the hair cells could be modulated by inflammation. Thus, intake of anti- and pro-inflammatory foods is of high interest.

METHODS

From the MICOL study population, 734 participants were selected that participated in the 2013 to 2018 examination including hearing ability and from which past data collected in 2005/2008 was available. ARHL status was determined and compared cross-sectionally and retrospectively according to clinical and lifestyle data including food and micronutrient intake.

RESULTS

ARHL status was associated with higher age but not with education, smoking, relative weight (BMI), and clinical-chemical blood markers in the crossectional and retrospective analyses. Higher intake of fruit juices among ARHL-participants was seen cross-sectionally, and of sugary foods, high-caloric drinks, beer, and spirits retrospectively. No difference was found for the other 26 food groups and for dietary micronutrients with the exception of past vitamin A, which was higher among normal hearing subjects.

CONCLUSIONS

Pro-inflammatory foods with a high-sugar content and also beer and spirits were found to be assocated with positive ARHL-status, but not anti-inflammatory foods. Diet could be a candidate for lifestyle advice for the prevention of ARHL.

Machine Learning Models for the Hearing Impairment Prediction in Workers Exposed to Complex Industrial Noise: A Pilot Study

Objectives:

To demonstrate the feasibility of developing machine learning models for the prediction of hearing impairment in humans exposed to complex non-Gaussian industrial noise.

Design:

Audiometric and noise exposure data were collected on a population of screened workers (N = 1,113) from 17 factories located in Zhejiang province, China. All the subjects were exposed to complex noise. Each subject was given an otologic examination to determine their pure-tone hearing threshold levels and had their personal full-shift noise recorded. For each subject, the hearing loss was evaluated according to the hearing impairment definition of the National Institute for Occupational Safety and Health. Age, exposure duration, equivalent A-weighted SPL (L_Aeq), and median kurtosis were used as the input for four machine learning algorithms, that is, support vector machine, neural network multilayer perceptron, random forest, and adaptive boosting. Both classification and regression models were developed to predict noise-induced hearing loss applying these four machine learning algorithms. Two indexes, area under the curve and prediction accuracy, were used to assess the performances of the classification models for predicting hearing impairment of workers. Root mean square error was used to quantify the prediction performance of the regression models.

Results:

A prediction accuracy between 78.6 and 80.1% indicated that the four classification models could be useful tools to assess noise-induced hearing impairment of workers exposed to various complex occupational noises. A comprehensive evaluation using both the area under the curve and prediction accuracy showed that the support vector machine model achieved the best score and thus should be selected as the tool with the highest potential for predicting hearing impairment from the occupational noise exposures in this study. The root mean square error performance indicated that the four regression models could be used to predict noise-induced hearing loss quantitatively and the multilayer perceptron regression model had the best performance.

Conclusions:

This pilot study demonstrated that machine learning algorithms are potential tools for the evaluation and prediction of noise-induced hearing impairment in workers exposed to diverse complex industrial noises.

The effect of simultaneous exposure to cigarette smoke and noise on distortion product otoacoustic emissions in rats

Cigarette smoking is a possible risk factor for hearing loss. However, the impact of simultaneous exposure to noise and smoke on hearing has remained controversial. This study investigated the combined effect of exposure to cigarette smoking and noise on hearing loss. Three groups of male Wistar rats (275 ± 25 g) were subjected to white noise (102 ± 0.5 dB), cigarette smoking (20 cigarettes), and both cigarette smoking and noise for 8 h and 10 days inside the exposure chamber. The control group was exposed to neither noise nor smoke. Distortion product otoacoustic emissions (DPOAE) were measured before any intervention, and it was repeated 1, 7, and 21 days after the last exposure. One-day postexposure to noise, cigarette smoking, and both cigarette smoking and noise, the mean of DPOAE amplitudes decreased significantly ( p < 0.05) between, respectively, 5.7-30.7, 1.5-7.5, and 5.2-32.6 dB within the frequency range of 4620-9960. Temporal DPOAE change in rats exposed to noise or both cigarette smoking and noise was not significantly different ( p > 0.05). DPOAE amplitudes returned to the baseline values in the group subjected to smoking 21 days postexposure. The most permanent change was observed in rats exposed to both cigarette smoking and noise. Accordingly, simultaneous subacute exposure to noise and cigarette smoking increases the effect of noise on permanent hearing loss. Therefore, smoking workers exposed to noise might be at a greater risk of developing hearing loss, and it is recommended that authorities in charge take note of this evidence.

Sex-Related Cochlear Impairment in Cigarette Smokers

Background

A number of studies have documented the influence of cigarette smoking on hearing. However, the association between sex and hearing impairment in smokers as measured by otoacoustic emissions (OAEs) has not been clearly established. The aim of this study was to analyze sex-specific effects of smoking on hearing via conventional and ultra-high-frequency pure tone audiometry (PTA), and OAEs, specifically spontaneous OAEs, click-evoked OAEs, and distortion-product OAEs.

Material/Methods

The study included 84 healthy volunteers aged 25–45 years (mean 34), among them 46 women (25 non-smokers and 21 smokers) and 38 men (16 non-smokers and 22 smokers). The protocol of the study included otoscopic examination, tympanometry, low-, moderate-, and ultra-high-frequency PTA, evaluation of spontaneous click-evoked (CEAOEs) and distortion-product otoacoustic emissions (DPOAEs), assessment of the DP-grams for 2f₁-f₂ (f₁ from 977 to5 164 Hz), and input/output function at L₂ primary tone level of 40–70 dB SPL.

Results

Smokers and non-smokers did not differ significantly in terms of their hearing thresholds assessed with tone audiometry. Male smokers presented with significantly lower levels of CEAOEs and DPOAEs than both male non-smokers and female smokers.

Conclusions

Smoking does not modulate a hearing threshold determined with PTA at low, moderate, and ultra-high frequencies, but causes a significant decrease in OAE levels. This effect was observed only in males, which implies that they are more susceptible to smoking-induced hearing impairment. Sex-specific differences in otoacoustic emissions level may reflect influences of genetic, hormonal, behavioral, and/or environmental factors.

Occupational noise-induced hearing loss in auto part factory workers in welding units in Thailand

Objectives:

Most workers in auto part factories in Thailand are usually exposed to excessive noise in their workplace. This study aimed to assess the level of occupational noise-induced hearing loss and investigate risk factors causing hearing loss in auto part factory workers in the welding units in Thailand.

Methods:

This was a cross-sectional study. One hundred eighty subjects were recruited from 356 workers in the welding unit of three factories. Sixty eligible subjects in each factory were selected by systemic random sampling. The subjects were interviewed using a face-to-face questionnaire. Noise exposure levels and audiograms were measured by a noise dosimeter and an audiometer, respectively.

Results:

The findings confirmed that noise exposure levels of 86-90 dB (A) and exceeding 90 dB (A) significantly increased the risk of hearing loss in either ear. A noise exposure level exceeding 90 dB (A) significantly increased the prevalence of hearing loss in both ears. Regarding, a 10-pack-year smoking history increased the prevalence of hearing loss in either ear or both ears. In addition, subjects with employment duration exceeding 10 years significantly developed hearing loss in either ear.

Conclusions:

The engineering control or personal control by wearing hearing protection device should be used to decrease noise exposure levels lower than 85 dB (A) for 8 h. Moreover, if the exposure level reaches 85 dB (A) for 8 h, the employer needs to implement a hearing conservation program in the workplace.

Status of Hearing Loss and Its Related Factors among Drivers in Zahedan, South-Eastern Iran

Objective:

This study aims to investigate loss of hearing among drivers in Zahedan, southeastern Iran.

Patients and Methods:

This study carried out on a total of 1836 drivers in Zahedan in 2013. Loss of hearing in both ears was measured at 250, 1000, 2000, 3000, 4000, 6000, and 8000 Hertz. The demographic variables, blood parameter and anthropometric data were recorded through interview and examinations. Data were analyzed in Stata.12 software using paired t-tests, McNemar test and Multiple Logistic Regression.

Results:

The mean age was 38.2±9.8 years. The highest mean hearing thresholds in the right and left ears were 25.7±9.1 and 27.7±9.1, respectively at 250 Hz. There was significant difference between left and right ears hearing threshold at all frequencies (P<0.001), and the highest difference occurred at 250 Hz. Hearing threshold in the left ear was greater than in the right ear at all frequencies. Hearing threshold was correlated to marital status, type of license, and vehicle, smoking, age, and driving history at all frequencies (P<0.01), and also significantly correlated to blood sugar and cholesterol levels at 250 and 500 Hz in both left and right ears (P<0.01).

Conclusion:

In conclusion, high levels of noise increase hearing threshold with greatest damage to the left ear. Therefore, drivers should be periodically examined for ear damage in accordance to variables affecting loss of hearing. Moreover, drivers must be educated about usage of appropriate ear-plugs during driving, especially for the left ear.

Is Hearing Impairment Associated with Rheumatoid Arthritis? A Review

Background:

Rheumatoid arthritis (RA) is a systemic, inflammatory disease that affects 1% of the population. The auditory system may be involved during the course of disease; however the association of RA and hearing impairment has not been clearly defined.

Objective:

The objective of this review is to evaluate published clinical reports related to hearing impairment in patients with RA. Furthermore, we discuss possible pathologies and associated factors as well as new treatment modalities.

Method:

A thorough literature search was performed using available databases including Pubmed, Embase, Cochrane and ComDisDome to cover all relative reports. The following keywords were used: hearing loss, hearing difficulties, hearing disorders, hearing impairment, sensorineural hearing loss, conductive hearing loss, mixed hearing loss, autoimmune hearing loss, drug ototoxicity, drug-induced hearing loss, hearing test, audiometry, auditory dysfunction and rheumatoid arthritis.

Conclusion:

Based on our review it can be postulated that patients with RA are at higher risk of hearing impairment compared to healthy subjects in their course of the disease. The hearing impairment in RA seems to be a multifactorial condition; however the mechanisms of injury, as well as the relative risk factors, are not completely clear. This review can aid to clarify this condition and is a guide for further evaluation. To the best of our knowledge, this is the first review of hearing impairment in RA.

GRHL2 genetic polymorphisms may confer a protective effect against sudden sensorineural hearing loss

Genetic polymorphisms in grainyhead‑like 2 (GRHL2) variants were examined for their suspected association with sudden sensorineural hearing loss (SSHL). Between January 2009 and April 2014, 190 patients with SSHL, who were diagnosed at the Departments of Otorhinolaryngology Head and Neck Surgery at Kaihua People's Hospital and Hangzhou First People's Hospital, were selected for the present study and defined as the SSHL group. A group of 210 healthy individuals were defined as the control group. Polymerase chain reaction (PCR)‑restriction fragment length polymorphism was used to detect GRHL2 genotypes, using genomic DNA isolated from peripheral blood as PCR templates. GRHL2 rs611419 genetic polymorphisms conferred a protective effect against SSHL (AT+TT vs. AA: OR=0.63, 95% CI=0.41‑0.98, P=0.038). In addition, rs10955255 polymorphisms were associated with a reduced risk of SSHL (AA vs. GG: OR=0.54, 95% CI=0.31‑0.95, P=0.032; GA+AA vs. GG: OR=0.58, 95% CI=0.38‑0.89, P=0.012). Combined genotypes of rs611419, rs10955255 and rs6989650 in the GRHL2 gene are also associated with a reduced risk of SSHL (P=0.035). In subjects who consumed alcohol, co‑occurrence of 3‑8 variant alleles conferred increased resistance to SSHL, compared with the occurrence of 0‑2 variant alleles (OR=0.40, 95% CI=0.21‑0.76, P=0.004). GRHL2 genetic polymorphisms, rs611419 and rs10955255, have a protective role against SSHL and reduce the risk of SSHL. However, rs6989650 is not associated with SSHL.

Cigarette smoking causes hearing impairment among Bangladeshi population

Lifestyle including smoking, noise exposure with MP3 player and drinking alcohol are considered as risk factors for affecting hearing synergistically. However, little is known about the association of cigarette smoking with hearing impairment among subjects who carry a lifestyle without using MP3 player and drinking alcohol. We showed here the influence of smoking on hearing among Bangladeshi subjects who maintain a lifestyle devoid of using MP3 player and drinking alcohol. A total of 184 subjects (smokers: 90; non-smokers: 94) were included considering their duration and frequency of smoking for conducting this study. The mean hearing thresholds of non-smoker subjects at 1, 4, 8 and 12 kHz frequencies were 5.63 ± 2.10, 8.56±5.75, 21.06 ± 11.06, 40.79 ± 20.36 decibel (dB), respectively and that of the smokers were 7 ± 3.8, 13.27 ± 8.4, 30.66 ± 12.50 and 56.88 ± 21.58 dB, respectively. The hearing thresholds of the smokers at 4, 8 and 12 kHz frequencies were significantly (p<0.05) higher than those of the non-smokers, while no significant differences were observed at 1 kHz frequency. We also observed no significant difference in auditory thresholds among smoker subgroups based on smoking frequency. In contrast, subjects smoked for longer duration (>5 years) showed higher level of auditory threshold (62.16 ± 19.87 dB) at 12 kHz frequency compared with that (41.52 ± 19.21 dB) of the subjects smoked for 1-5 years and the difference in auditory thresholds was statistically significant (p<0.0002). In this study, the Brinkman Index (BI) of smokers was from 6 to 440 and the adjusted odds ratio showed a positive correlation between hearing loss and smoking when adjusted for age and body mass index (BMI). In addition, age, but not BMI, also played positive role on hearing impairment at all frequencies. Thus, these findings suggested that cigarette smoking affects hearing level at all the frequencies tested but most significantly at extra higher frequencies.

Personally Modifiable Risk Factors Associated with Pediatric Hearing Loss: A Systematic Review

BACKGROUND

Pediatric hearing loss is an increasingly recognized problem with significant implications. Increasing our quantitative understanding of potentially modifiable environmental risk factors for hearing loss may form the foundation for prevention and screening programs.

OBJECTIVE

To determine whether specific threshold exposure levels of personally modifiable risk factors for hearing loss have been defined, with the overarching goal of providing actionable guidance for the prevention of pediatric hearing loss.

DATA SOURCES

A systematic review was performed. Computerized searches of PubMed, EMBASE, and the Cochrane Library were completed and supplemented with manual searches.

REVIEW METHODS

Inclusion/exclusion criteria were designed to determine specific threshold values of personally modifiable risk factors on hearing loss in the pediatric population. Searches and data extraction were performed by independent reviewers.

RESULTS

There were 38 criterion-meeting studies, including a total of 50,651 subjects. Threshold noise exposures significantly associated with hearing loss in youth included: (1) more than 4 hours per week or more than 5 years of personal headphone usage, (2) more than 4 visits per month to a discotheque, and (3) working on a mechanized farm. Quantified tobacco levels of concern included any level of in utero smoke exposure as well as secondhand exposure sufficient to elevate serum cotinine.

CONCLUSIONS

Specific thresholds analyses are limited. Future studies would ideally focus on stratifying risk according to clearly defined levels of exposure, in order to provide actionable guidance for children and families.

Interaction between noise and cigarette smoking for the outcome of hearing loss among women: a population-based study

BACKGROUND

We investigated the interaction between exposure to noise and smoking in relation to prevalence of hearing loss among women.

METHODS

A sample of women aged 20-49 years (n = 1,723) from a population-based cross-sectional study carried out in Brazil in 2006 was examined. Hearing loss was assessed using a yes-no validated question. Biological interaction was analyzed using the additive scale and measured with interaction contrast ratio (ICR) and assessment of dose-response relationship.

RESULTS

The combined effect of exposure to noise and cigarette smoking on hearing loss (adjusted prevalence ratio (PRadj) = 3.94, 95% confidence interval (CI): 2.81, 5.52) was greater than expected based on the additive single effects of smoking (PRadj = 1.39, 95% CI: 1.07, 1.81) and noise (PRadj = 2.66, 95% CI: 1.86, 3.82). ICR estimates were not statistically significant. The prevalence of hearing loss among noise-exposed women increased with duration of smoking (P trend = 0.026), number of cigarettes smoked per day (P trend = 0.034), cumulative tobacco use (P trend = 0.030), and early age at smoking initiation (P trend = 0.047).

CONCLUSIONS

Noise and smoking may have a combined effect on hearing loss but further studies are still needed. A dose-response relation of smoking for the noise effect among women is suggested.

Noise exposure and hearing impairment among Chinese restaurant workers and entertainment employees in Hong Kong

Background

Noise-induced hearing loss (NIHL) is a major concern in the non-manufacturing industries. This study aimed to investigate the occupational noise exposure and the NIHL among Chinese restaurant workers and entertainment employees working in the service industry in Hong Kong.

Methods

This cross-sectional survey involved a total of 1,670 participants. Among them, 937 were randomly selected from the workers of Chinese restaurants and 733 were selected from workers in three entertainment sectors: radio and television stations; cultural performance halls or auditoria of the Leisure and Cultural Services Department (LCSD); and karaoke bars. Noise exposure levels were measured in the sampled restaurants and entertainment sectors. Each participant received an audiometric screening test. Those who were found to have abnormalities were required to take another diagnostic test in the health center. The “Klockhoff digit” method was used to classify NIHL in the present study.

Results

The main source of noise inside restaurants was the stoves. The mean hearing thresholds showed a typical dip at 3 to 6 KHz and a substantial proportion (23.7%) of the workers fulfilled the criteria for presumptive NIHL. For entertainment sectors, employees in radio and television stations generally had higher exposure levels than those in the halls or auditoria of the LCSD and karaoke bars. The mean hearing thresholds showed a typical dip at 6 KHz and a substantial proportion of the employees fulfilled the criteria for presumptive NIHL (38.6%, 95%CI: 35.1–42.1%). Being male, older, and having longer service and daily alcohol consumption were associated with noise-induced hearing impairment both in restaurant workers and entertainment employees.

Conclusion

Excessive noise exposure is common in the Chinese restaurant and entertainment industries and a substantial proportion of restaurant workers and entertainment employees suffer from NIHL. Comprehensive hearing conservation programs should be introduced to the service industry in Hong Kong.

Occupational noise-induced hearing loss in Indian steel industry workers: an exploratory study

OBJECTIVE

The present study focused on exploring the current level of hearing protection and subsequently determined the prevalence of occupational noise-induced hearing loss among casting and forging industry workers.

BACKGROUND

The casting and forging industry provides employment to a significant portion of the population.

METHOD

The level of hearing protection was assessed through questionnaire survey of 572 workers. Out of these workers, 165 and another control group of 57 participants were assessed by formal audiometry. Audiometric tests were conducted at frequencies of 1.0 KHz to 8.0 KHz.The occurrence of hearing loss was determined on the basis of a hearing threshold level with a low fence of 25 dB. Student's test and ANOVA were used to compare the various groups; a p value < .05 was considered statistically significant.

RESULTS

More than 90% of the workers sampled showed significant hearing loss at medium and high frequencies. The analyses revealed a higher prevalence of significant hearing loss among the forging workers compared with the workers associated with the other activities.

CONCLUSIONS

The workers of the Indian steel industry are highly exposed to occupational noise. The majority of workers are not protected from noise-induced hearing loss. There is a need to provide special ear protectors for workers engaged in forging. A complete hearing protection program, including training, audiometry, job rotation, and the use of hearing protection devices, needs to be introduced.

Relative risk of elevated hearing threshold compared to ISO1999 normative populations for Royal Australian Air Force male personnel

OBJECTIVE

This paper introduces a new method to calculate relative risks of elevated hearing thresholds, at various ages and frequencies, between a study population and ISO1999:2003: Annex A Screened, Annex B Unscreened and ISO1999 Section 5.3 adjustment for noise exposure using Annex A Screened data. We demonstrate this method on a study population of male Royal Australian Air Force personnel.

STUDY DESIGN

Using a retrospective cohort design, hearing thresholds were assessed in 583 F-111 aircraft maintenance personnel, 377 technical-trade comparisons and 492 non-technical comparisons using pure-tone audiometry. A quantile regression model was used determine whether an association exists between median hearing thresholds and F-111 maintenance, adjusting for possible confounders. The new method involves using quantile regression models with bootstrapped standard errors to estimate percentiles for the study population and thus determine the probability of a greater than 25 dB hearing threshold. This was done for the three ISO datasets as follows; for the ISO1999 Annex A screened population data the formula provided allows the calculation of these probabilities. ISO1999 Annex B unscreened population data only provides the values for the 10th, 50th and 90th percentiles at ages 30, 40, 50 and 60 only, therefore it was necessary to fit a curve to these values in order to estimate the probabilities. For ISO1999 Section 5.3 adjustment for noise exposure population we used the Annex A screened population data plus the formula. The probabilities were then divided to give the relative risks of a greater than 25 dB hearing threshold, at various ages and frequencies.

RESULTS

While no difference was observed between the three groups, the model identified a number of significant confounders, namely tinnitus, smoking, diabetes and the use of anti-depressant medications. Relative risks were high at frequencies 2 kHz and less for the study population of all ages compared to ISO A screened data. The increased relative risks at 4 and 6 kHz give the appearance of a "noise notch" for ages 30 and 40 years. The comparison with the ISO B unscreened data are significantly less than one for frequencies above 2 kHz, particularly for young men and greater than one less than 2 kHz. The relative risks for the comparison to the ISO A screened data with ISO 5.3 adjustments, are highest for young men decreasing with age, with the highest relative risk are at frequencies less than 2 kHz.

CONCLUSIONS

This paper demonstrates a new method for quantifying the probability of a clinically relevant hearing loss and the relative risk of the loss due to a risk factor. Prior to this, researchers were reduced to simplistic methods such as visual comparison of deciles which did not enable the estimation of risk. The new method can use all observed hearing thresholds per study participant, adjust for known confounding factors such age and gender, and calculate the relative risk of a clinically relevant increase in hearing threshold due to a risk factor of interest.

Hearing impairment in F-111 maintenance workers: the study of health outcomes in aircraft maintenance personnel (SHOAMP) general health and medical study

BACKGROUND

We sought to examine hearing loss in a group from the Royal Australian Air Force who undertook fuel tank maintenance on F-111 aircraft, with exposure to formulations containing ototoxins, relative to two different comparison groups.

METHODS

Using pure-tone audiometry, hearing thresholds were assessed in 614 exposed personnel, 513 technical-trade comparisons (different base, same job), and 403 non-technical comparisons (same base, different job). We calculated percentage loss of hearing (PLH) and used regression models to examine whether there was an association between PLH and F-111 fuel tank maintenance, adjusting for possible confounders. In addition, the difference between the observed hearing thresholds and the expected thresholds based on an otologically normal population (ISO-7029-2003) was determined.

RESULTS

The PLH ranged from nil to 96 (median 1.5, quartiles 0.3, 5.5). A logistic regression model showed no statistically significant difference in PLH among the three exposure groups (exposed vs. non-technical controls 1.1: 95% CI 0.7, 2.0 and exposed vs. technical OR 0.9: 95% CI 0.6, 1.3). The model also highlighted a number of other risk factors for PLH including age, tinnitus, smoking, depression, and use of depression medications. However, at all eight frequencies measured, all populations had lower than expected hearing thresholds based on published ISO-7029 medians.

CONCLUSIONS

Although there was no difference in PLH between the three exposure groups, the study did reveal a high degree of hearing loss between the 3 groups and a normal population.

Effects of light smoking on extra-high-frequency auditory thresholds in young adults

There have been few reports showing a correlation between hearing levels and life style in young people. In this study, we succeeded in sensitively evaluating hearing levels in 51 young male adults of 21-23 years in age by 12 k Hz extra-high-frequency auditory thresholds, which cannot be measured by usual audiometry devices for clinical use. Noise exposure, alcohol consumption and sleeping time did not affect hearing levels in young adults. Auditory thresholds of 12 kHz frequency in smokers were significantly (p < 0.05) higher than those in non-smokers, while there were no differences in 1 kHz, 4 kHz and 8 kHz frequencies of hearing levels between smokers and non-smokers. Since the Brinkman Index (BI; cigarettes/day multiplied by number of years) of smokers in this study was from 12 to 60, our results suggest that even light smoking of less than 20 cigarettes/day for 3 years can result in the development of hearing loss of 12 kHz frequency in young adults. Binary logistic regression analysis again showed a correlation between hearing loss (≥ 40 dB of auditory thresholds in 12 kHz frequency) and light smoking (12 ≤ BI ≤ 60). Thus, this study showed that auditory threshold at 12 kHz frequency could be a sensitive marker for hearing in young adults. More importantly, we for the first time provided epidemiological evidence that light smoking might affect hearing level at 12 kHz frequency and revealed a new risk of light smoking.

The effects of smoking and alcohol consumption on age-related hearing loss: the Blue Mountains Hearing Study

OBJECTIVES

We aimed to investigate the temporal association between smoking or alcohol consumption and hearing loss, and to confirm previously published cross-sectional associations.

DESIGN

The Blue Mountains Hearing Study is a population-based survey of age-related hearing loss conducted in a defined suburban area, west of Sydney. Hearing loss was measured in 2956 participants (aged 50+ yrs) and was defined as the pure-tone average of frequencies 0.5, 1.0, 2.0, and 4.0 kHz >25 dB HL in the better ear (bilateral hearing loss). Alcohol consumption and smoking status were measured using an interviewer-administered questionnaire. Logistic regression was used to obtain odds ratios (OR) with 95% confidence intervals (95% CI) that compared the chances of having hearing loss in participants who did or did not smoke or consume alcohol, after adjusting for other factors previously reported to be associated with hearing loss.

RESULTS

The prevalence of hearing loss at baseline was 33.0% (N = 929) and the 5-year incidence of hearing loss was 17.9% (N = 156). Cross-sectional analysis demonstrated a significant protective association between the moderate consumption of alcohol (>1 but < or =2 drinks/day) and hearing function in older adults (compared with nondrinkers), OR 0.75 (95% CI, 0.57 to 0.98). Current smokers not exposed to occupational noise had a significantly higher likelihood of hearing loss after adjusting for multiple variables, OR 1.63 (95% CI, 1.01 to 2.64). A formal likelihood ratio test demonstrated that the interaction between smoking and noise exposure was not significant (p = 0.23). When the joint effects of alcohol consumption and smoking on hearing were explored, there was a trend for alcohol to have a protective relationship with hearing loss in smokers, but this was not statistically significant. However, the 5-year incidence of hearing loss was not predicted by either smoking or alcohol consumption.

CONCLUSIONS

This study confirms previously reported associations between alcohol consumption or smoking and prevalent hearing loss, but these were not demonstrated in temporal data. Other risk factors could confer greater vulnerability or cause the initial damage to hearing. Future large population-based studies, exploring the influence of other risk factors on the development of age-related hearing loss are warranted.

Low and high frequency tonal threshold audiometry: comparing hearing thresholds between smokers and non-smokers

Cigarette smoking can cause many potentially fatal diseases and worsen others. Numerous studies have shown the relationship between smoking and hearing loss. However, the increase in auditory threshold in high frequency arising from smoking has been very little described.

Aim

to compare low and high frequency auditory thresholds among a group of smoking and non-smoking male individuals between 18 and 40 years.

Study design

Cross-sectional.

Materials and Methods

by means of low and high frequency tonal threshold audiometry we studied 30 male individuals between 18 and 40 years and 30 non-smokers of matching age and gender.

Results

auditory thresholds were different between smokers and non-smokers, being worse in the former. Although within normal ranges, auditory thresholds in low frequencies were higher among smokers. In high frequencies we noticed a marked increase in auditory thresholds among smokers.

Conclusion

we found statistically significant difference in auditory thresholds in low and high frequencies, among young male individuals, smokers and non-smokers, being worse in the former.

Subjective audiological tests and transient evoked otoacoustic emissions in patients with rheumatoid arthritis: analysis of the factors affecting hearing levels

We investigated hearing functions in patients with rheumatoid arthritis (RA) using audiological tests and transient evoked otoacoustic emissions (TEOAEs). The study group consisted of 20 adult patients with RA (7 males, 13 females); 20 adult healthy subjects without RA (7 males, 13 females) were recruited as controls. All patients were evaluated by pure tone audiometry, high frequency audiometry, tympanometry and TEOAEs. There were no statistical differences between the study and control groups with respect to the pure tone and high frequency audiometries. TEOAE results of 1.0-2.0 kHz % and of 1.5 and 3.0 kHz amplitude values were significantly lower, and ipsilateral stapes reflex threshold value at 1.0 kHz was significantly higher in the study group when compared to respective values in the control group. In elderly patients and those with longer disease duration, RA nodules and higher methotrexate cumulative doses, hearing thresholds increased and TEOAE values decreased. In active stage of the disease, hearing thresholds diminished and in higher Brinkman Index values, TEOAE values decreased. Compliance values decreased in patients with higher Ritchie Articular Index, C-reactive protein, erythrocyte sedimentation rate and platelet counts, and longer disease duration. Sensorineural hearing loss is generally observed in patients with RA, and this condition may be detected by TEOAEs in an early period of the disease. Inflammation during the active stage of the disease and the subsequent fibrosis may cause conductive hearing loss of varying degrees. In those patients detected as having initiation of TEOAE decrease, vasodilator treatment and antioxidant drugs may be useful in protecting the inner ear.

Occupational noise, smoking, and a high body mass index are risk factors for age-related hearing impairment and moderate alcohol consumption is protective: a European population-based multicenter study

A multicenter study was set up to elucidate the environmental and medical risk factors contributing to age-related hearing impairment (ARHI). Nine subsamples, collected by nine audiological centers across Europe, added up to a total of 4,083 subjects between 53 and 67 years. Audiometric data (pure-tone average [PTA]) were collected and the participants filled out a questionnaire on environmental risk factors and medical history. People with a history of disease that could affect hearing were excluded. PTAs were adjusted for age and sex and tested for association with exposure to risk factors. Noise exposure was associated with a significant loss of hearing at high sound frequencies (>1 kHz). Smoking significantly increased high-frequency hearing loss, and the effect was dose-dependent. The effect of smoking remained significant when accounting for cardiovascular disease events. Taller people had better hearing on average with a more pronounced effect at low sound frequencies (<2 kHz). A high body mass index (BMI) correlated with hearing loss across the frequency range tested. Moderate alcohol consumption was inversely correlated with hearing loss. Significant associations were found in the high as well as in the low frequencies. The results suggest that a healthy lifestyle can protect against age-related hearing impairment.

Associations of carotid intima-media thickness, tobacco smoking and overweight with hearing disorder in a general population sample

It has been argued that smoking or overweight might contribute to hearing disorder by atherogenic narrowing of the nutrient arteries to the cochlea. The carotid intima-media thickness (CIMT) is a surrogate marker for generalized atherosclerosis. We analyzed a subgroup (n=2619) from a general population sample in north-eastern Germany aged 45-81 years (Study of Health in Pomerania, SHIP). Assessments included self-statements about hearing disorder and medical examinations of CIMT. Using ordinal logistic regression for data analysis and after adjustment for cigarettes per day, waist circumference, diabetes, exposure to noise, age and sex, we found CIMT remained a predictor of hearing disorder (odds ratio 1.8, 95% confidence interval 1.0-3.2). Cigarettes per day and waist circumference were related to CIMT but not to hearing disorder. The findings suggest a positive association between CIMT and hearing disorder.

ALDH2 polymorphisms and bone mineral density in an elderly Japanese population

INTRODUCTION

Osteoporosis is a multifactorial genetic disease which greatly increases the risk of bone fracture in elderly persons.

METHODS

Four hundred and three recipients of a community health screening program were examined for the presence/absence of osteoporosis and 11 kinds of gene polymorphisms as a means of determining the relation between these gene polymorphisms and osteoporosis. The gene polymorphisms screened were: alcohol sensitivity-associated polymorphisms of alcohol dehydrogenase (ADH2) Arg47His, aldehyde dehydrogenase (ALDH2) Glu487Lys, smoking sensitivity-associated polymorphisms of glutathione S transferase (GST) M1, (GST)T1, NAD(P)H quinone oxidoreductase 1 (NQO1) C609T, inflammation-associated polymorphisms of interleukin-1beta (IL-1B)T-31C, tumor necrosis factor alpha (TNF-alpha) T-1031C, endothelial constitutive nitric oxide synthase (ecNOS) Glu298Asp, longevity-associated polymorphism of mitochondrial DNA (mtDNA) 5178 A/C, allergy-associated polymorphism of interleukin-4 (IL-4), and immunity-associated polymorphism of CD14.

RESULTS

A significant association was found between the ALDH2Glu478Lys gene polymorphisms and osteoporosis. In the osteoporosis group of patients, a significant difference was noted between the Lys/Lys group and the group comprising Glu/Lys and Glu/Glu groups (namely, the genotypes including Glu alleles). In the Lys/Lys group, after age, sex, BMI, smoking history and alcohol consumption history had been adjusted for, the morbidity rate was significantly elevated [odds ratio (OR): 3.33; 95% confidence interval (95% CI): 1.28-8.71; p=0.014], and the effect was even more evident in the sub-group of women with osteoporosis (OR: 4.31; 95% CI: 1.24-14.92; p=0.021).

CONCLUSIONS

The present results suggest that active prophylactic interventions such as dietary, exercise, and pharmacological therapies should be offered to non-carriers of the Glu allele (Lys/Lys).