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Abstract
Objectives This study was designed to assess occupational noise exposure levels, prevalence of temporary hearing loss and associated factors among textile industry workers in Amhara region, Ethiopia.
Design An institution-based, cross-sectional study was conducted between June and July 2022. Participants were selected via a simple random sampling technique.
Setting Textile industry workers in Bahir Dar and Kombolcha.
Participants A total of 413 study participants were included in the data analysis.
Procedures and analysis The data were collected using a structured questionnaire. Area noise exposure levels in different work sections were measured using a sound level meter. Data analysis was done using Stata Version 14.0 software. Bivariate and multivariable logistic regression analysis were used to identify factors associated with temporary hearing loss. Adjusted OR with 95% CI and p-value<0.05 were used to determine statistical significance.
Results A total of 413 workers participated in the study with a response rate of 97.9%. The age of respondents ranged from 22 to 59 years (median age 32 years). The prevalence of work-related temporary hearing loss was 38.7% (95% CI 34.14% to 43.6%). Weaving department (AOR=6.6, 95% CI 3.06 to 14.3) and higher sound pressure level (>90 dBA) (AOR=7.9; 95% CI 2.6 to 23.7) were significantly associated with work-related temporary hearing loss among textile workers.
Conclusions The prevalence of work-related temporary hearing loss among textile industry workers was high. Weaving department and higher sound pressure level were significantly associated with work-related temporary hearing loss. Implementation of noise reduction measures, particularly in the weaving department, should be prioritised. Provision and enforcement of the use of hearing protection devices and establishment of regular hearing screening programmes to monitor workers' auditory health are advisable.
- Anaesthesia in cardiology
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Data availability statement
Data are available upon reasonable request. The data used to support the findings of this study are available from the corresponding author upon reasonable request.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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STRENGTHS AND LIMITATIONS OF THIS STUDY
Noise exposure levels were measured across different departments within the textile industry using a sound level meter.
This study used a simple random sampling technique, enhancing the representativeness of the sample and reducing selection bias.
Another strength of the study was the assessment of temporary hearing loss in different sections of the textile industry.
The cross-sectional design limited the ability to establish causality or temporal relationships.
Other limitations included the inability to use a noise dosimeter for measuring personal noise exposure levels and the absence of audiometry testing to determine the extent of temporary hearing loss.
Introduction
Noise is defined as unpleasant, unwanted and disturbing sound regardless of its intensity or duration.1 Exposure to excessive sound levels in the workplace initially manifests as a temporary hearing loss or dullness of hearing, which may resolve within the first 16–24 hours after exposure.2 3 Temporary hearing loss refers to a change in the hearing threshold that recovers to baseline over time.4 The duration of recovery depends on several factors including exposure level, duration, the subject's age, exposure to other ototoxic factors, and frequency and pattern of exposure (intermittent or continuous).4 5 Hearing loss from high noise exposure in the workplace is a significant global health issue.6 WHO reports that approximately 600 million workers are exposed to harmful noise levels, with 16% of disabling hearing loss occurring in the adult population, in which 4 million cases are attributed to occupational noise exposure. From those, 7% and 21% are found in developed and developing countries, respectively.7 8
Globally, about 30 million workers are exposed to dangerous noise levels each day.9 WHO estimates indicate that hearing loss is the fourth leading cause of disability, with 360 million individuals living with disabling hearing loss in 2008, and over 466 million in 2018, incurring costs exceeding $750 billion annually worldwide. The number of people living with disabling hearing loss is predicted to rise to 630 million by 2030 and nearly 900 million by 2050.10
In the USA, approximately 22 million (25% of the general population) are workers exposed to harmful levels of occupational noise each year.11 In Britain, about 1.7 million workers encounter noise levels exceeding >85 dBA (A-weighted decibels).12 According to the Sixth European Working Conditions Survey conducted across 36 European countries, 28% of workers reported being exposed to excessive noise for at least a quarter of their time at work.13 In many low- and middle-income countries, excessive noise ranks as the largest compensable occupational hazard.14 In developing countries, including Ethiopia, workplace noise exposure is the second most common risk factor, after workplace injuries.15
The effects of workplace noise exposure are greater in developing regions than in developed countries.14 In developing countries, economic investments focus on industrialisation, while facing issues such as inadequate public health policies, weak regulatory frameworks, limited resources for preventive measures, a lack of noise prevention programmes and insufficient awareness of the consequences of excessive noise exposure.10 16
Different studies reported the prevalence of hearing loss in textile industry workers including in Gazipur (33.46%),17 Pakistan (38%),14 Nigeria (36%),18 Portugal (28.3%)19 and Addis Ababa (49%).20 In addition, different studies indicated that age,6 18 21 sex,6 21 22 educational level,6 intensity of noise exposure,14 20 alcohol drinking,22 cigarette smoking,3 22 working department,20 duration of employment,18 20–23 use of hearing protective devices (HPDs),3 23 24 ear discharge/infections,14 regularly taking ototoxic medications22 and previously working in a noisy environment22 were factors associated with work-related hearing loss (figure 1).
Conceptual framework showing the relationship between the subgroups of independent factors and work-related temporary hearing loss in the textile industries in Amhara region, Ethiopia (adapted from various references).9 10 13
In recent years, industries in Ethiopia have grown significantly and contributed to economic growth. However, working conditions in these industries pose risks due to lack of awareness of the associated health hazards in particular. Textile factories are among the occupational settings that pose a risk of hearing loss.19 Therefore, this study aimed to assess occupational noise exposure levels, prevalence of temporary hearing loss and associated factors among textile industry workers in Amhara region, Ethiopia. Our research also contributes valuable data that can be used as baseline information about the level and risk factors for work-related temporary hearing loss for health administrators, safety managers and researchers. Such data are also necessary for planning control and preventive programmes of noise exposure for workers aimed at protecting workers' hearing health.
Methods
Study design and period
An institution-based, cross-sectional study was conducted from 6 June to 2 July 2022.
Study setting
The study was conducted among workers in large-scale textile factories located in Bahir Dar and Kombolcha, Amhara region. Bahir Dar and Kombolcha textile factories were established in 1966 and 1986 in Bahir Dar and Kombolcha town, respectively. Bahir Dar is the capital city of the Amhara region and located 570 kilometers from Addis Ababa, Ethiopia's capital. Total textile factory workers in both industries numbered 2825 (1552 male and 1273 female), of which 2055 workers were involved in production processes. The number of workers involved in each work section in the Bahir Dar and Kombolcha textile factories, respectively, were 232 and 312 in spinning, 245 and 315 in weaving, 292 and 277 in processing and finishing, 288 and 94 in engineering, and 316 and 454 in administration.
Participants
Source population
All employees of the Bahir Dar and Kombolcha textile factories were the source population.
Study population
The study population comprised workers directly engaged in the production processes at Bahir Dar and Kombolcha textile factories.
Inclusion and exclusion criteria
Workers currently working in textile industries for a period of at least 6 months were included in the study,25 whereas workers who were on sick, annual or maternity leave and had permanent hearing loss during the data collection period were excluded from the study. Written informed consent was obtained from the study participants (online supplemental annex 1).
Supplemental material
Sample size and sampling procedures
The sample size was calculated using a single population proportion formula by assuming the prevalence of temporary hearing loss from the previous study: p=49%,20 95% CI, 5% margin of error and considering a 10% non-response rate. The total sample size for this study was 422 participants. Regarding the sampling procedure, the sample was proportionally allocated to each production section based on the total number of workers in each production department. After proportional allocation, a simple random sampling technique was used to select the study participants. In this study a total of 413 participants were selected including production workers from spinning (n=112), weaving (n=115), engineering (n=78) and processing and finishing (n=117) departments (figure 2).
Schematic representation of sampling techniques from different production departments of textile industries, 2022.
Study variables
The outcome variable of this study was work-related temporary hearing loss (Yes/No). There are a number of independent variables that affected the outcome variable (hearing loss) including sociodemographic factors such as age, sex, marital status, monthly income, educational status and duration of exposure or years of service in the textile factory. Other factors included individual or patient-related factors such as ear infection, head injury, sleep disorder, previous hearing test and taking ototoxic medications. Behavioural factors included use of HPDs, cigarette smoking, use of earphones for listening to music, and alcohol drinking. In addition, health and safety training related to harmful noise exposure, availability and use of HPDs, working departments, working hours per day, noise exposure level, work shift and previous occupational noise exposure were considered as risk factors for work related temporary loss (online supplemental annex 2).
Operational definitions
In this study, work-related temporary hearing loss was defined as participants who had experienced at least one temporary hearing loss symptom such as tinnitus, difficulty in communication, experiencing hearing problems and change in their hearing/ability to understand words immediately after leaving work that returned to baseline within 16 hours.26 27
Head injury: Have any history of head injury that included problems with ears.28
Ear infection: Have a history of ear infection under/above the age of 18 years and in this regard certain viral infections in the inner ear that destroy the cochlea, producing total deafness.28
Alcohol consumption: Consumption of any kind of alcohol at least twice a week.29
Cigarette smoking: Any employee who smokes one cigarette a day for at least 1 year.30
Sleeping disturbance problem: Participants were considered to have sleep disturbances if they reported at least one sleep problem from four items included on the Jenkins Sleep Scale.31
Work area noise exposure level: Average sound pressure level measured by sound level meter 1-minute intervals where <85 dBA is low noise, 85–90 dBA is moderate noise and >90 dBA is high noise level for 8 hours of exposure time per day.32
Use of hearing protection devices: Workers who use HPDs (either ear muff, ear canal or ear plug) during working hours.33
Earphone used: Any individual who uses earphones for listening to any sound (music, muzmur, radio, etc.) for more than 2 hours per day.34
Data collection procedures and quality assurance
Data collection procedures and tools
Data were collected using pretested, structured Amharic (local language) version questionnaires via face-to-face interview (online supplemental annex 2). In addition, structured observational checklists were used to assess the institution’s setup regarding noise control measures such as engineering control and the availability and utilisation of HPDs (online supplemental annex 3). The data collectors were one graduate environmental health professional and one college pharmacy student. Two supervisors strictly followed the day-to-day data collection processes. The noise levels in different departments of the textile industries were measured using an IEC 651, type II sound level meter. The sound level meter was held at arm’s length at ear height for those exposed workers and the microphone was placed in the direct source of noise. The readings were taken on SLOW measurement reading because the noise continued, and after taking one noise exposure level the instrument was switched off and restarted again for measuring other workers’ noise exposure levels. Since the noise was consistent or relatively constant and the workers spend the work shift in a fixed location, 10 measurements for 1-minute intervals were taken at workers’ head level.35 The participants’ average noise exposure level was calculated using the following logarithmic 256 formula:36
SPL (Sound Pressure Level)T=10 Log 
.
Data quality assurance
To assure the quality of data the English version of the questionnaire was translated into Amharic local language and back to English language to check its consistency. Two days of training were also given to both the data collectors and supervisors. Before starting the actual data collection, 5% of the questionnaires were pretested in the Abay garment factory in Gondar City and some corrections (eg, confusing words) were made as well as an estimation of the time taken for data collection. The reliability the questionnaires was assessed for outcome variables (cronbach αlpha (α)=0.722), sleep disturbance (α=0.6742) and overall factor variables (α=0.823). The principal investigator and supervisors checked and reviewed the completed questionnaires to ensure completeness and consistency of the information.
Data management and analysis
The collected data were manually entered into Epi data version 4.6 and exported into Stata version 14.0 for further analysis. Descriptive statistics were computed. Tables, graphs and charts were used to present the findings. To identify potential associated factors with temporary hearing loss among textile workers, logistic regression was performed. First, bivariable logistic regression was done and variables with a p-value<0.2 were exported to a multivariable logistic regressions analysis model to handle confounding variables. Finally, in multivariable logistic regression, adjusted odds ratio (AOR) with 95% confidence interval (CI) and p-value≤0.05 were used to determine strength and significant association, respectively. The model’s fitness (p=0.24) and multicollinearity (<1.48) were also assessed.
Patient and public involvement
None.
Results
Sociodemographic, work-related and noise exposure characteristics of participants
A total of 413 respondents participated in this study with a response rate of 97.9%. Reasons for non-participation were unwillingness of participants and incomplete records. The age of respondents ranged from 22 to 59 years, with a median (IQR) of 32 (28–38) years. More than half (58.35%) of the participants were married. Less than half (45.04%) of the respondents had attended technical/college diploma programmes. More than a quarter (31.72%) of the participants were paid between 4000 and 6000 ETB (Ethiopian birr) per month, with a median (IQR) of 3900 (3185 and 4700) ETB.
Among the participants, less than a quarter (16.22%) had previous noise exposure history.
In the current industry, the majority (63.20%) of the respondents were exposed to noise levels exceeding 90 dBA. More than a quarter of the workers were from the spinning department (27.12%) and processing and finishing department (27.6%).
The majority (82.8%) of respondents did not receive occupational health and safety training. Regarding shift work, the production departments (weaving, spinning, and processing and finishing departments) operate with three shifts per day; in contrast, the engineering departments do not have designated work shifts. There is no workplace shift or job rotation in either sector of the textile industries (table 1).
Sociodemographic, work-related and noise exposure-related characteristics of textile industry workers in Amhara region, Ethiopia, June 2022 (N=413)
Noise exposure level of respondents from different departments
Regarding level of noise exposure experienced by employees in various departments, the majority of the respondents in the weaving department (n=78, 71.5%) were exposed to noise levels >90 dBA, while nearly all the employees in the spinning department (n=95, 95%) were exposed to noise levels >90 dBA. While half of the respondents (n=45, 57.69%) worked in the engineering department where they were exposed to noise levels >90 dBA, half of the respondents (n=59, 51.75%) worked in the processing and finishing department where they were exposed to noise levels <85 dBA (table 2).
Numbers of workers in each department at each noise exposure level among textile industry workers in Amhara region, Ethiopia, June 2022 (N=413)
Individual and behavioural characteristics of participants
In terms of previous hearing tests, no pre-employment hearing assessments were conducted in the textile industry. Only 20 participants (4.84%) were tested at a health institution on their own initiative, and 21 respondents (5.08%) had taken ototoxic medication. The majority of the study participants (n=286, 69.25%) reported having sleep disorders, while 22 (5.33%) reported head injuries and 35 (8.47%) reported ear infection or drainage issues at or below the age of 18 years.
Among the total respondents, more than a quarter (33.41%) consumed alcohol, and nearly all (94.67%) did not smoke cigarettes. The majority (89.1%) did not use HPDs when working. Most workers (71.58%) stated that the main reasons for not using HPDs were that they were not available or provided by employers, while 12.57% cited discomfort. More than half (52.78%) of the respondents listened to music, radio or other audio. A quarter (25.42%) used earphones for listening to music, and of those less than a quarter (19.12%) used earphones for 2 hours or less per day (table 3).
Individual and behavioural characteristics of textile industry workers in Amhara region, Ethiopia, June 2022 (N=413)
Observational analysis of noise-related work environments
The observation regarding noise levels indicated that the weaving, spinning and engineering departments were excessively noisy, making it difficult to communicate with someone standing 3 feet away without shouting, in contrast to the processing and finishing department. High noise level areas in the textile factory lacked signs or posters to protect workers from spontaneous noise generated by various machines during inspections.
No measures were taken to isolate or enclose noisy machinery from the rest of the workplace operations. Only 45 participants (10.9%) used HPDs (figure 3), including six participants (1.45%) who used ear muffs and 39 participants (9.45%) who used ear plugs. Although a health and safety committee existed in the textile industry, it focused on product safety and quality rather than workers’ safety and health. As a result, there was no ongoing preventive health programme to educate employees about safe noise exposure levels and the effects of noise on their health. Additionally, no training was provided to employees exposed to continuous noise levels above 85 dBA. However, training related to new employment, equipment or other changes was implemented for workers in the textile industry.
Use of hearing protective devices (HPDs) among textile industry workers in Amhara region, Ethiopia, June 2022.
Prevalence of work-related temporary hearing loss
In this study, the prevalence of work-related temporary hearing loss among textile industry workers was 38.7% (95% CI 34.14% to 43.6%). Of the study participants, more than a quarter (30.5%) reported experiencing tinnitus, with 29.4% having it in one ear and nearly three-quarters (70.6%) in both ears. Additionally, more than a quarter (35.8%) had difficulty communicating with friends after leaving work. Moreover, more than a quarter (28.6%) noticed ringing/temporary hearing difficulty after arriving home and less than a quarter (17.7%) of participants noticed changes in their hearing or ability to understand everyday speech. The prevalence of temporary hearing loss with respect to noise exposure level was 3.13% (<90 dBA), 18.13% (85–90 dBA) and 78.75% (>90 dBA) (figure 4).
The prevalence of work-related temporary hearing loss (WRTHL) by noise exposure level (A-weighted decibel, dBA) among textile industry workers in Amhara region, June 2022.
Factors associated with work-related temporary hearing loss
The variables of age, education level, working department, noise exposure level and use of HPDs were significantly associated with temporary hearing loss at p<0.2 in bivariable analysis. The weaving department and noise exposure level greater than 90 dBA were significantly linked to work-related temporary hearing loss among textile industry workers (p<0.05). Workers in the weaving department had a 6.6 times higher odds of experiencing temporary hearing loss compared with those workers in the processing and finishing department (AOR=6.6, 95% CI 3.06 to 14.3). Additionally, workers exposed to noise levels greater than 90 dBA had a 7.9 times higher odds of developing temporary hearing loss compared with those exposed to noise levels less than 85 dBA (AOR=7.9, 95% CI 2.6 to 23.7) (table 4).
Bivariable and multivariable logistic regression analyses of temporary hearing loss among textile industry workers in Amhara region, Ethiopia, June 2022 (N=413)
Discussion
Textile industry workers are at an increased risk of developing noise-induced hearing loss due to exposure to significant levels of noise.17 This study aimed to assess the prevalence and risk factors of work-related temporary hearing loss among textile industry workers in the Amhara region of Ethiopia. In this study, the prevalence of work-related temporary hearing loss was found to be 38.7% (95% CI 34.14% to 43.6%). Additionally, working in the weaving department and exposure to noise levels exceeding 90 dBA were identified as factors for work-related temporary hearing loss.
This finding is consistent with studies conducted among textile factory workers in Gazipur (33.46%),17 Pakistan (38%),14 Nigeria (36%)18 and Turkey (40%)37; this similarity may be attributed to comparable data collection methods (face-to-face interviews), similar noise exposure levels in textile industries and shared study designs (cross-sectional study design).
However, the prevalance in the present study is lower than that found in studies conducted in Tanzania (58.5%)21 and Addis Ababa (49%).20 This discrepancy may be due to differences in data collection methods, working hours per day (exposure time) and industrial setup. In this study, the data were collected via face-to-face interviews and no participants worked more than 8 hours per day. In contrast, the study conducted in Addis Ababa used self-administered questionnaires, which may have overestimated the problem, and 43.8% of employees in that industry worked more than 8 hours per day. Another reason for the discrepancy might be differences in assessment tools and variation in the data collection period. In the Tanzanian study, hearing loss assessment was performed using an audiometer, and data were collected over a long period (May–December). In this study, hearing loss was assessed via symptom-based methods with data collected over 1 month.
Conversely, the present study reports a higher prevalence than studies conducted in Portugal (28.3%)19 and Thamine (25.7%).38 This discrepancy might be attributed to differences in sample size and participant characteristics; nearly all (93.4%) of the participants in Thamine were females. Additionally, the Portuguese study was conducted in an industry where noise preventive measures have been implemented for approximately 10 years, and workers used ear protectors and audiometry tests on workers who worked in noisy environment were assessed.38
In this study, 30.5% of workers reported tinnitus, which is higher than the 23% found in a study conducted in Tanzania among textile industry workers.21 Tinnitus is a significant issue for noise-exposed workers and can adversely affect sleep, concentration, mood and overall quality of life. Noise exposure can lead to tinnitus, which may progress to hearing loss.39 This difference might be due to the fact that the majority of workers in the present study (84%) were exposed to noise levels exceeding 85 dBA, together with a lack of noise control measures such as job rotation from high to low noise areas, no isolation of noise machine from workers, and the absence of HPDs.
In this study, 35.6% of workers reported difficulties with telephone conversations, which is lower than the result (44.85%) from a similar study conducted among textile industry workers in Addis Ababa, Ethiopia.20 This difference might be attributed to differences in data collection methods, variation in industry setups, and differences in noise exposure levels and duration of noise exposure.
Our results also indicated that workers in the weaving department were more likely to experience temporary hearing loss compared with those in the processing and finishing department. This could be due to the higher noise levels commonly reported in the weaving section of the textile factory.40 The elevated noise levels in this department might be caused by outdated machinery, poor workplace design and overcrowding, all of which contribute to excessive noise exposure. Additionally, more than half (63.4%) of the workers in the weaving department were male, which may further explain the increased association with hearing loss Sex difference in hearing could play a role in these findings as males have been shown to be more affected by hearing loss compared with females.6 21 22 Hormonal differences, particularly the protective role of oestrogen in females, may influence hearing outcomes. Oestrogen plays a critical role in the development of the inner ear and the hearing process, potentially offering some protection against hearing loss in females. Additionally, anatomical and physiological differences in the auditory system, such as the longer cochlea found in males, can impact hearing. The shorter cochlea in females may result in greater stiffness of the basilar membrane, while males tend to have increased inner hair cell loss, which could explain the higher prevalence of hearing loss among males.41–43
In this study, the average sound level in the weaving department was 96.2 dBA, which is consistent with studies conducted in Pakistan and India, which reported noise exposure levels of 95.3 dBA14 and 87.3 dBA,44 respectively.
The distribution of temporary hearing loss across different departments showed that the highest prevalence was found in the weaving department (49.4%), followed by the spinning (22.5%), engineering (17.5%) and processing and finishing (10.6%) departments. This result aligns with a study conducted in Jordan, where 30–53% of workers in the weaving department reported hearing loss.45
However, the prevalence of temporary hearing loss in the weaving department found in the present study (49.4%) was higher than that reported in Portugal, where 38.8% of workers in the weaving section experienced hearing loss.19 This difference may be due to the Portuguese study implementing preventive measures, including the use of HPDs, over a decade. Conversely, the prevalence observed in the present study is lower than in Kenya, where 60% of weaving department workers reported hearing loss.46 This difference might be attributed to factors such as the absence of previous hearing pathology and varying exposure durations.
In this study, sound pressure levels above 90 dBA were found to be significantly associated with temporary hearing loss. The growing intensity of urban noise, coupled with industrial noise from general machine components, exacerbates this issue in the textile industry.47
According to the Occupational Safety Health Administration (OSHA) standards and the Ethiopian occupational safety and health directives regulation, the level of noise and the corresponding time exposure are set at 90 dBA for 8 hours, 92 dBA for 6 hours, 95 dBA for 4 hours, 97 dBA for 3 hours, 100 dBA for 2 hours, 102 dBA for 1 and 1.5 hours, 105 dB A for 1 hour, 110 dBA for 30 minutes and 115 dBA for 15 minutes.10 32
When compared with low-intensity sound, high-intensity sound has been shown to have more harmful effects.17 The temporary hearing loss were significantly associated with sound pressure levels >90 dBA might be due to workers who are exposed to noise for 8 hours at levels higher than 90 dBA experiencing discomfort (tinnitus) in their ears and head for a long time after leaving work and potentially experiencing hearing loss that might either be temporary or permanent depending on the time period for which they were exposed.27 This result was supported by studies conducted among textile industry workers in Pakistan,14 Nigeria18 and Portugal.19
A strength of the present study is measuring noise exposure levels using a sound level meter across different departments. The use of a simple random sampling technique reduces selection bias, which further strengthens the study’s reliability. Another notable strength is the assessment of temporary hearing loss in various sections of the textile industry, providing valuable insights across departments. However, the study also has some limitations. The cross-sectional design limits the ability to establish causality or temporal relationships between noise exposure and temporary hearing loss. Moreover, the inability to use a noise dosimeter for measuring personal noise exposure levels and the absence of audiometry testing restricts the study’s ability to precisely determine the extent of temporary hearing loss among workers.
Conclusions
In this study, the prevalence of work-related temporary hearing loss among textile industry workers was notably high, affecting 38.7% of participants. Regarding factors associated with temporary hearing loss, workers in the weaving department and those exposed to higher sound pressure levels (>90 dBA) significantly experienced temporary hearing loss. This finding highlights the need for targeted interventions, particularly in the weaving department, where noise levels are especially elevated. Implementing noise reduction strategies, enforcing the use of hearing protection devices, and establishing regular hearing screening programmes are essential steps to protect workers’ auditory health and prevent long-term hearing damage among textile industry workers.
Data availability statement
Data are available upon reasonable request. The data used to support the findings of this study are available from the corresponding author upon reasonable request.
Ethics statements
Patient consent for publication
Ethics approval
This study involved human participants. The University of Gondar evaluated the study protocol based on Declaration of Helsinki principles and approved it as ethically sound research with letter Ref. No/IPH/2129/2014, and official permission was obtained from Kombolcha and Bahir Dar textile industries managers. After the purpose, benefit and risk was explained, written informed consent was obtained from the study participants. Privacy and confidentiality of information given by each respondent were maintained properly and personal identifiers were removed. Participants gave informed consent to participate in the study before taking part.
Acknowledgments
The authors would like to thank the University of Gondar, Wollo University, Bahir Dar and Kombolcha textile industries managers, study participants, data collectors, supervisors and friends.
References
Footnotes
Contributors ATY was responsible for conceptualising this research paper, literature review and organisation, preparation of the draft research proposal document, organising the data collection process, and preparation of draft data analysis and interpretation of the results and manuscript write-up. GA was involved in the design of the study, development of data collection tools, interpretation and presentation of the findings and in reviewing the manuscript at several stages, and was a primary supervisor for the study. EAW also contributed to the preparation of data collection tools, commenting on and editing the interpretation of statistical output and commenting on and approving the submitted version of the manuscript. AAB contributed to the preparation of the draft data analysis and interpretation of the results. BK contributed to the preparation of the data collection tools and manuscript writing. ATY was responsible for the writing of this manuscript, the accuracy of the data as guarantor, and takes full responsibility for the study and had access to the data. All authors read and approved the final manuscript.
Funding The authors received financial support for data collection for the study from the University of Gondar (Ref. No.AC/V/P/02271/2014).
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.