Duration Of Noise Exposure Research Articles

Hearing Threshold of Dental Practitioners in Various Clinical Settings

Objectives: The purpose of this study was to evaluate the relationship of the working environment’s noise intensity level, distance from the source of noise, duration of the noise exposure and age of dentist to the hearing threshold level of general dental practitioners, dental students and dental supervisors and to determine if the noise in a dental facility can cause noise induced hearing loss. Materials and Methods: Thirty participants per group were enrolled in the study. The noise intensity level was measured with the use of noise level meter placed at the collar area of the operator and at the center of the room. The distance of noise exposure was set to 0.15 meters to simulate close proximity noise exposure of general dental practitioners and dental students while 2 meters was set for dental supervisors to represent exposure away from the sound source. The duration of noise exposure and age of the participants were determined with the use of a questionnaire. The participants were requested to have audiometric testing to determine their hearing threshold level. Results: There was a weak negative correlation of noise intensity level to hearing threshold level at 1000 Hz, 2000 Hz for the left ear and 2000 Hz for the right ear. However, distance from sound source, duration of sound exposure and age of the dentist were positively correlated to hearing threshold level at 3000 Hz, 4000 Hz, 6000 Hz and 8000 Hz. Noise intensity level did not reach the hazardous level on an 8-hour time weighted average. Conclusion: The Noise intensity level in a dental environment is considered to be safe to dentists who are practicing their profession. The age of the dentist and the duration of exposure from noise are the major factors in the increase in the hearing threshold level of a dental practitioner.

Advanced noise-induced deafness among workers in singapore - what has changed?

Context:Noise-induced deafness (NID) contributes a significant disease burden internationally, and is a leading occupational disease in Singapore.Aims:This study profiles the epidemiological characteristics of advanced noise-induced deafness (NID(A)) cases and explores whether these have evolved with time.Settings and Design:A quantitative retrospective analysis of prior NID(A) cases was performed. National records of NID(A) cases from 2001 to 2010 were obtained, with permission from the Ministry of Manpower, consisting of worker audiograms, case records, and noise monitoring reports.Methods and Material:Comparison was made with data from a prior study (127 cases, 1985–1994) to identify shifts in NID(A) epidemiology; 71 out of 73 NID(A) case records (2001–2010) from the national data were reviewed.Statistical Analysis Used:Statistical Package for Social Sciences (IBM) was used for statistical analysis.Results:Mean noise exposure (24–29.6 years) and age at diagnosis (48–54.6 years) have risen. Total case numbers (127 to 73 cases), average hearing loss levels (61.5 to 56.0 A-weighted decibels), and delayed reporting of NID(A) cases (82.7% to 47.9%) have decreased. Metal manufacturing and marine industries remain top contributors (69.1%, from 68.5%); 31% were noncompliant with hearing protector (personal protective equipment, PPE) use and 38% did not use PPE properly.Conclusions:NID(A) case profiles have shifted over time, with reduced case numbers, lower hearing loss levels at diagnosis, and earlier case notification, possibly linked to improvements in legislative coverage and NID prevention programs. Changes in age and average duration of noise exposure may be related to these improvements. Early case notification, PPE compliance, and proper usage should be focus areas for NID prevention and hearing conservation programs.

Occupational noise exposure and hypertension: the Dongfeng-Tongji Cohort Study

The association between occupational noise exposure and hypertension is unclear. We aimed to explore the association in a Chinese population and to summarize our findings with previous published articles. The cross-sectional study included 22,450 participants from Dongfeng-Tongji Cohort Study. In a subsample of 10,636 subjects, we assessed the association between hearing loss and hypertension. For the meta-analysis, we searched PubMed and EMBASE until April 2017, and the pooled odds ratio (OR) was combined using a random effect model. Compared with participants without occupational noise exposure, the risk of hypertension was significantly higher for noise exposure duration ≥20 (OR = 1.09, 95% confidence interval [CI] = 1.00–1.18). In the sex-specific analysis, the association was only significantly pronounced in males (OR = 1.16, 95% CI = 1.03–1.31), but not in females (OR = 1.01, 95% CI = 0.88–1.14). In the subsample analyses, hearing loss, which was an indicator for exposure to loud noise, was associated with a higher risk of hypertension, especially for participants who were bilateral hearing loss (OR = 1.39, 95% CI = 1.24–1.54). In the meta-analysis, the pooled OR for the association between occupational noise exposure and hypertension was 1.25 (95% CI = 1.10–1.42). On the basis of an indicator for exposure to occupational noise, the cross-sectional study and meta-analysis identified occupational noise exposure as a potential risk factor for increased hypertension risk.

The combined effect of cigarette smoking and occupational noise exposure on hearing loss: evidence from the Dongfeng-Tongji Cohort Study

Combined effect of cigarette smoking and occupational noise exposure on hearing loss has rarely been evaluated among Chinese population, especially among females. This cross-sectional study was conducted in 11196 participants of Dongfeng-Tongji cohort study. Smoking status was self-reported through questionnaire and occupational noise exposure was evaluated through workplace noise level and/or the job titles. Hearing loss was defined as a pure-tone mean of 25 dB or higher at 0.5, 1, 2, and 4 kHz in both ears. Compared with participants without occupational noise exposure, the risk of hearing loss was significantly higher for noise exposure duration ≥20 (OR = 1.45, 95%CI = 1.28–1.65). The association was particularly evident among individuals who were males (OR = 1.74, 95%CI = 1.45–2.08) and aged ≥ 70 (OR = 1.74, 95%CI = 1.30–2.33). Similarly, the risks increased with the increasing of pack-years in males and all age groups except for those aged <60. As to the combined effect, the hearing loss risk was highest for noise exposure duration ≥20 and pack-years ≥25 (OR = 2.41, 95%CI = 1.78–3.28), especially among males (OR = 2.42, 95%CI = 1.74–3.37) and those aged ≥70 (OR = 2.76, 95%CI = 1.36–5.60). Smoking may be an independent risk factor for hearing loss. And it may synergistically affect hearing when combined with occupational noise exposure, especially among males and older participants.

Nocturnal Road Traffic Noise Exposure and Children's Sleep Duration and Sleep Problems.

Almost half of the European Union (EU)’s population is exposed to road traffic noise above levels that constitute a health risk. Associations between road traffic noise and impaired sleep in adults have consistently been reported. Less is known about effects of noise on children’s sleep. The aim of this study was to examine the association between nocturnal road traffic noise exposure and children’s parental-reported sleep duration and sleep problems. The present cross-sectional study used data from The Norwegian Mother and Child Cohort Study. Parental report of children’s sleep duration and sleep problems at age 7 was linked to modelled levels of residential night-time road traffic noise. The study population included 2665 children from Oslo, Norway. No association was found between road traffic noise and sleep duration in the total study population (odds ratio (OR): 1.05, 95% confidence interval (CI): [0.94, 1.17]), but a statistically significant association was observed in girls (OR: 1.21, 95% CI: [1.04, 1.41]). For sleep problems, the associations were similar (OR: 1.36, 95% CI: [0.85, 2.16]) in girls. The ORs are presented for an increase of 10 dB. The findings suggest there is an association between road traffic noise and sleep for girls, underlining the importance of protecting children against excessive noise levels.

Clinical and audiological characteristics of 1000 Hz audiometric notch patients

PurposeAmong the hearing loss patients, we can confirm that the hearing loss of the specific frequency decreases, such as the 2000Hz notch in otosclerosis and the 4000Hz notch (c5-dip) in noise-induced hearing loss. The 1000Hz notch (c3-dip), however, is rarely studied. We fortuitously encountered a group of patients with a 1kHz hearing loss and report it with a review of the literature. MethodsOtological history, audiogram, diagnosis, occupation, and history of noise exposure were reviewed from charts and telephone interview, and compared between c3-dip and c5-dip patients (n=98). ResultsThirty-one patients (mean age: 46.2years) demonstrated 1kHz hearing loss; these included 11 males. The pure-tone threshold was 37.97dB at 1kHz and the average threshold was 22.38dB at other frequencies. In the c3-dip group, tinnitus was the most common complaint, while sudden sensorineural hearing loss and idiopathic tinnitus (n=8 each) were the most common diagnoses. Female patients and unilateral cases were more common in the c3-dip than in the c5-dip group, and ear fullness was more common in the c3-dip group than in the c5-dip group. The duration of occupation-related noise exposure was longer in the c5 group, and head or ear trauma was more frequent in the c3-dip group. ConclusionWe have defined a new clinical entity of 1kHz hearing loss in patients, defined as the c3-dip, which was clinically and audiologically distinct from the c5-dip. Further study is needed to clarify this new entity of hearing loss.

Benefits of Extended High-Frequency Audiometry for Everyone

Benefits of Extended High-Frequency Audiometry for Everyone

Prevalence of Onihl in Manufacturing Industry

Objective: To find out the prevalence of occupational noise induced hearing loss (ONIHL) among the workers in a manufacturing engineering industry and to observe the effect of duration of noise exposure on hearing of workers. Study design:Observational case control study. Study sample: Of 236 subjects, 118 cases each in noise (>85dB) exposed (group A) and control (group B). All the subjects were subjected to audiometry and pure tone averages for frequencies 500Hz, 1kHz, 2kHz and 4kHz were calculated and compared. Results: Showed an overall prevalence of 41.5% hearing loss in the exposed study group A out of which 77.5% had mild while 22.5% had moderate hearing loss as compared to only 2.5% overall prevalence in unexposed group B, which was found to be statistically significant (p<0.005).The present study also compared the audiometry results with duration of exposure which revealed a hearing loss of 3.7% among workers exposed for duration of 5-9yrs, 51.6% for duration of 10- 14yrs and 100% for duration of ≥15yrs. Conclusion: ONIHL is prevalent in form of mild to moderate hearing loss within the manufacturing industry.

Genetic variation in EYA4 on the risk of noise-induced hearing loss in Chinese steelworks firm sample

ObjectivesNoise-induced hearing loss is one of the most serious occupational diseases worldwide. It is caused by interactions between environmental and genetic factors. The purpose of this study was to examine...

Auditory brainstem responses for click and CE-chirp stimuli in individuals with and without occupational noise exposure.

Introduction:Encoding of CE-chirp and click stimuli in auditory system was studied using auditory brainstem responses (ABRs) among individuals with and without noise exposure.Materials and Methods:The study consisted of two groups. Group 1 (experimental group) consisted of 20 (40 ears) individuals exposed to occupational noise with hearing thresholds within 25 dB HL. They were further divided into three subgroups based on duration of noise exposure (0–5 years of exposure-T1, 5–10 years of exposure-T2, and >10 years of exposure-T3). Group 2 (control group) consisted of 20 individuals (40 ears). Absolute latency and amplitude of waves I, III, and V were compared between the two groups for both click and CE-chirp stimuli. T1, T2, and T3 groups were compared for the same parameters to see the effect of noise exposure duration on CE-chirp and click ABR.Result:In Click ABR, while both the parameters for wave III were significantly poorer for the experimental group, wave V showed a significant decline in terms of amplitude only. There was no significant difference obtained for any of the parameters for wave I. In CE-Chirp ABR, the latencies for all three waves were significantly prolonged in the experimental group. However, there was a significant decrease in terms of amplitude in only wave V for the same group.Discussion:Compared to click evoked ABR, CE-Chirp ABR was found to be more sensitive in comparison of latency parameters in individuals with occupational noise exposure. Monitoring of early pathological changes at the brainstem level can be studied effectively by using CE-Chirp stimulus in comparison to click stimulus.Conclusion:This study indicates that ABR's obtained with CE-chirp stimuli serves as an effective tool to identify the early pathological changes due to occupational noise exposure when compared to click evoked ABR.

Prevalence, awareness, and preventive practices of noise-induced hearing loss in a plywood industry

Introduction: Noise exposure is the most common preventable cause of occupational noise-induced hearing loss (NIHL); however, once acquired, it is irreversible. The predominant damage occurs to the hair cells and their associated nerves leading to the hearing loss. Objective: To determine the prevalence and also to evaluate the awareness and practices regarding prevention of occupational NIHL in the selected industry, to emphasize the critical importance of educating industry workers regarding NIHL and its prevention. Methodology: All staff working in the selected plywood industry excluding the ones with chronic otitis media were included. Relevant history, demographics, and clinical data were collected using prestructured questionnaire based proforma. All of them underwent pure tone audiometry. Results: Of 111 workers who were exposed to noise, 51.85% had NIHL, the average ambient noise being 80.5 dB. The most common complaints in workers with NIHL was hearing loss (52.6%), difficulty in hearing in noisy surroundings (43.9%), and difficulty in telephonic conversations (38.6%). There was a significant number (47.4%) who were asymptomatic. The majority had mild (56.1%) and moderate (38.6%) hearing loss. Majority of them with NIHL belonged to the age group of 30–60 years. This study showed a positive correlation between duration of noise exposure and degree of hearing loss. No one has ever used any sort of ear protection devices nor aware of health effects associated with noise exposure and its prevention. Conclusion: Considering zero awareness, screening, education, and prevention methods are emphasized to reduce the impact of noise exposure at workplace.

Determining the effect of worker exposure conditions on the risk of hearing loss in noisy industrial workroom using Cox proportional hazard model

In noisy workrooms, exposure conditions such as noise level, exposure duration and use of hearing protection devices are contributory factors to hearing loss. The aim of this study was to determine the effect of exposure conditions on the risk of hearing loss using the Cox model. Seventy workers, employed in a press workshop, were selected to study their hearing threshold using an audiometric test. Their noise exposure histories also were analyzed. The results of the Cox model showed that the job type, smoking and the use of protection devices were effective to induce hearing loss. The relative risk of hearing loss in smokers was 1.1 times of non-smokers The relative risk of hearing loss in workers with the intermittent use of protection devices was 3.3 times those who used these devices continuously. The Cox model could analyze the effect of exposure conditions on hearing loss and provides useful information for managers in order to improve hearing conservation programs.

Predictive factors of occupational noise-induced hearing loss in Spanish workers: A prospective study.

The purpose of our study was to identify the main factors associated with objective noise-induced hearing loss (NIHL), as indicated by abnormal audiometric testing, in Spanish workers exposed to occupational noise in the construction industry. We carried out a prospective study in Tenerife, Spain, using 150 employees exposed to occupational noise and 150 age-matched controls who were not working in noisy environments. The variables analyzed included sociodemographic data, noise-related factors, types of hearing protection, self-report hearing loss, and auditory-related symptoms (e.g., tinnitus, vertigo). Workers with pathological audiograms had significantly longer noise-exposure duration (16.2 ± 11.4 years) relative to those with normal audiograms (10.2 ± 7.0 years; t = 3.99, P < 0.001). The vast majority of those who never used hearing protection measures had audiometric abnormalities (94.1%). Additionally, workers using at least one of the protection devices (earplugs or earmuffs) had significantly more audiometric abnormalities than those using both protection measures simultaneously (Chi square = 16.07; P < 0.001). The logistic regression analysis indicates that the use of hearing protection measures [odds ratio (OR) = 12.30, confidence interval (CI) = 4.36-13.81, P < 0.001], and noise-exposure duration (OR = 1.35, CI = 1.08-1.99, P = 0.040) are significant predictors of NIHL. This regression model correctly predicted 78.2% of individuals with pathological audiograms. The combined use of hearing protection measures, in particular earplugs and earmuffs, associates with a lower rate of audiometric abnormalities in subjects with high occupational noise exposure. The use of hearing protection measures at work and noise-exposure duration are best predictive factors of NIHL. Auditory-related symptoms and self-report hearing loss do not represent good indicators of objective NIHL. Routine monitoring of noise levels and hearing status are of great importance as part of effective hearing conservation programs.

The Impact of Different Permissible Exposure Limits on Hearing Threshold Levels Beyond 25 dBA.

Background:Development of noise-induced hearing loss is reliant on a few factors such as frequency, intensity, and duration of noise exposure. The occurrence of this occupational malady has doubled from 120 million to 250 million in a decade. Countries such as Malaysia, India, and the US have adopted 90 dBA as the permissible exposure limit. According to the US Occupational Safety and Health Administration (OSHA), the exposure limit for noise is 90 dBA, while that of the US National Institute of Occupational Safety and Health (NIOSH) is 85 dBA for 8 hours of noise exposure.Objectives:This study aimed to assess the development of hearing threshold levels beyond 25 dBA on adoption of 85 dBA as the permissible exposure limit compared to 90 dBA.Patients and Methods:This is an intervention study done on two automobile factories. There were 203 employees exposed to noise levels beyond the action level. Hearing protection devices were distributed to reduce noise levels to a level between the permissible exposure limit and action level. The permissible exposure limits were 90 and 85 dBA in factories 1 and 2, respectively, while the action levels were 85 and 80 dBA, respectively. The hearing threshold levels of participants were measured at baseline and at first month of postshift exposure of noise. The outcome was measured by a manual audiometer. McNemar and chi-square tests were used in the statistical analysis.Results:We found that hearing threshold levels of more than 25 dBA has changed significantly from pre-intervention to post-intervention among participants from both factories (3000 Hz for the right ear and 2000 Hz for the left ear). There was a statistically significant association between participants at 3000 Hz on the right ear at ‘deteriorated’ level ( χ² (1) = 4.08, φ = - 0.142, P = 0.043), whereas there was worsening of hearing threshold beyond 25 dBA among those embraced 90 dBA.Conclusions:The adoption of 85 dBA as the permissible exposure limit has preserved hearing threshold level among participants at 3000 Hz compared to those who embraced 90 dBA.

Early prognosis of noise-induced hearing loss

ObjectiveOccupationally acquired noise-induced hearing loss (NIHL) is the most prevalent occupational disease in Austria and among the most common in many other countries. Because of the wide variation in hearing...

Hearing profile of brazilian forestry workers' noise exposure.

Introduction Researchers studying the hearing health of forestry workers have revealed the presence of a noise-induced hearing loss (NIHL) in this population and have concluded that the vibration of the equipment, the carbon monoxide released by motors, and pesticides might also contribute to NIHL. Objective To analyze the noise exposure in the Brazilian forestry industry workers and the effects on hearing. Methods The study sample comprised 109 employees of a company that specialized in reforestation. Their participants' mean age was 35.5 years (21 to 54 years), mean tenure at the company was 3.9 years (1 to 13 years), and mean total duration of noise exposure was 12.3 years (1 to 30 years). The existing documentation reporting on the jobs risk analysis was examined, noise level was measured, and pure tone audiometry was performed in all participants. Participants were divided into three groups according to their noise exposure levels in their current job. Results Of the participants who were exposed to noise levels less than 85 dBA (decibels with A-weighting filter), 23.8% had hearing loss, and 5.5% of the participants who were exposed to noise ranging from 85 to 89.9 dBA and 11% of the participants who were exposed to noise greater than 90 dBA had audiogram results suggestive of NIHL. Conclusion The implementation of a hearing loss prevention program tailored to forestry workers is needed.

The Risk of Noise on the Hearing Levels of Individuals Working in Orthotic and Prosthetic Sector = خطر الضوضاء على مستويات سمع الأشخاص الذين يعملون في مجال الأطراف الاصطناعية و الأجهزة المساندة

Objective: To identify the effect of noise exposure on the hearing threshold of subjects working in the sector of orthotics and prosthetics. Methods: The hearing threshold of all subjects was tested using a screening audiometer based on the procedure recommended for industrial audiometry. Results: Subjects working in the sector of orthotics and prosthetics appeared to have noise induced hearing loss as indicated by their hearing threshold and/or by the presence of notch on their audiograms at 4 or 6 kHz. It was also found that longer duration of noise exposure appears to result in worse hearing threshold. Conclusions: Our results indicate that subjects working in the sector of orthotics and prosthetics are exposed to hazardous noise levels that have negative effects on their hearing. This is why the implementation of a hearing conservation program that prevents further damage for the hearing of those subjects becomes crucial.

Cardiovascular disease mortality among retired workers chronically exposed to intense occupational noise.

The aim of this study, conducted among retired workers (≥65 years), is to estimate the association between long-term risk of cardiovascular disease (CVD) death and (1) duration of occupational noise exposure in career and (2) noise-induced hearing loss (NIHL), the latter being used as an indicator of adverse effects for long-term exposure to occupational noise. Data from screening activities of occupational NIHL were paired to data from death records and were used for this study. A nested case-control analysis was performed. Each case was matched with three controls for length of follow-up and economic sector. A total of 161 CVD deaths occured during an average follow-up of 6.8 years. Conditional logistic regression models were used to estimate the risk (OR) of CVD death by tertiles of duration of noise exposure and of NIHL. Conditional logistic regression models indicated that prolonged duration of noise exposure (≥36.5 years) (3rd tertile) was associated with an increased risk of CVD death (OR 1.70; 95 % CI 1.10-2.62), as compared with shorter duration (<27 years) (first tertile). Moderate NIHL (2nd tertile) (OR 1.64; 95 % CI 1.04-2.6) and severe NIHL (3rd tertile) (OR 1.66; 95 % CI 1.06-2.60) were also associated with an increase in risk of CVD death. Results are consistent with recent findings on the chronic effects of occupational noise exposure persisting after retirement although it is less than during active working life.

Occupational noise exposure and noise-induced hearing loss are associated with work-related injuries leading to admission to hospital

This study focuses on work-related injuries that required admission to hospital in a population of male workers exposed to occupational noise (≥80 dBA) which some displayed a hearing loss due to their exposure. The study population count 46 550 male workers, 1670 (3.6%) of whom incurred at least one work-related injury requiring admission to hospital within a period of 5 years following hearing tests conducted between 1987 and 2005. The noise exposure and hearing loss-related data were gathered during occupational noise-induced hearing loss (NIHL) screening. The hospital data were used to identify all members of the study population who were admitted, and the reason for admission. Finally, access to the death-related data made it possible to identify participants who died during the course of the study. Cox proportional hazards model taking into account hearing status, noise levels, age and cumulative duration of noise exposure at the time of the hearing test established the risk of work-related injuries leading to admission to hospital. For each dB of hearing loss, a statistically significant risk increase was observed (HR=1.01 dB 95% CI 1.006 to 1.01). An association (HR=2.36 95% CI 2.01 to 2.77) was also found between working in an occupational ambient noise ≥100 dBA and the risk of injury. From a safety perspective, this issue is highly relevant; especially when workers are exposed to intense ambient noise and NIHL.

Longitudinal changes in hearing threshold levels of noise-exposed construction workers

Longitudinal analysis of audiometric data of a large population of noise-exposed workers provides insight into the development of noise-induced hearing loss (NIHL) as a function of noise exposure and age, particularly during the first decade of noise exposure. Data of pure-tone audiometry of 17,930 construction workers who underwent periodic occupational hearing screening at least twice during a 4-year period were available for analysis. These concerned all follow-up measurements of the baseline cohort described by Leensen et al. (Int Arch Occup Environ Health 84:577-590, 2011). Linear mixed models explored the relationship between the annual rate of change in hearing and noise exposure level, exposure duration, and age. Data of 3,111 workers who were tested on three occasions were used to investigate the pattern of hearing loss development. The mean annual deterioration in hearing in this study population was 0.54 dB/yr, and this became larger with increasing noise exposure level and increasing age. Remarkably, during the first decade of noise exposure, an improvement in hearing threshold levels (HTLs) was observed. The change in hearing over three measurements showed a concave development of hearing loss as a function of time, which corresponds to NIHL development. Overall, hearing deteriorated over the measurement period. Because HTLs at follow-up were better than those obtained at baseline, no statement can be made about the NIHL development during the first decade of noise exposure. This improvement in HTLs rather resembles the result of measurement variation in occupational screening audiometry than an actual improvement in hearing ability.