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Table of Contents
ORIGINAL ARTICLE
Year : 2018  |  Volume : 1  |  Issue : 1  |  Page : 31-35

Prevalence of Hearing Loss and Tinnitus with Correlation to the Usage of Protective Hearing Equipment among Airport Workers


1 Department of Otolaryngology - Head and Neck Surgery, King Fahad Medical City and Research Center, Riyadh, Saudi Arabia
2 King Abdullah Ear Specialist Center, Otolaryngology Head and Neck Surgery Department, Riyadh, Saudi Arabia
3 Audiology and Balance Unit, Otolaryngology - Head and Neck Surgery Department, King Saud University, Riyadh, Saudi Arabia
4 Department of Otolaryngology- Head and Neck Surgery, King Abdulaziz University Hospital, Jeddah, King Saud University, Saudi Arabia

Date of Web Publication7-Mar-2018

Correspondence Address:
Ahmed H Saleem
Department of Otolaryngology-Head and Neck Surgery, King Fahad Medical City and Research Center, Riyadh
Saudi Arabia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/JNSM.JNSM_9_18

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  Abstract 

Objectives: Epidemiological studies have shown that tinnitus and occupational hearing loss are common symptoms in the working population. Only few studies have assessed the aforementioned symptoms in this population, none of which have assessed airport field workers (AFWs), thus the need for our study. Methods: A cross-sectional study was conducted among AFWs at King Khalid International Airport in Riyadh. The sample size was calculated to be 380. Each was asked to fill a self-administered questionnaire and undergo pure-tone audiometry to assess hearing level. The questionnaire assessed the participants' demographics, usage of protective hearing equipment (PHE) as well as prevalence and characteristics of tinnitus if present. Results: Of all field workers, 300 (78%) have agreed to participate in the study. A number of 180 (60%) participants believe that PHE prevents noise-related hearing loss. Of all participants, 114 (38%) workers use PHE. No association was found between the participants' belief regarding PHE benefits and their usage of the equipment (P = 0.473). Tinnitus was reported by 81 (27%) of the whole sample. Most of the participants, i.e., 171 (57%) were found to have hearing impairment (>25 dB HL) at low frequencies (0.5, 1, and 2 kHz) in comparison to 144 (48%) at high frequencies (4 and 8 kHz). Conclusion: Even with relatively good knowledge about the importance of PHE, only few workers actually use them. Thus, frequent audiometric screening tests as well as enforcement of PHE usage by AFWs need to be introduced by the airport administrations.

Keywords: Airport workers, hearing loss, occupational, protective hearing equipment, tinnitus


How to cite this article:
Saleem AH, Alkharboush G, Almazyed O, AlHilal S, Alnajashi I, Al-Andejani T, Al Momani M, Hagr A. Prevalence of Hearing Loss and Tinnitus with Correlation to the Usage of Protective Hearing Equipment among Airport Workers. J Nat Sci Med 2018;1:31-5

How to cite this URL:
Saleem AH, Alkharboush G, Almazyed O, AlHilal S, Alnajashi I, Al-Andejani T, Al Momani M, Hagr A. Prevalence of Hearing Loss and Tinnitus with Correlation to the Usage of Protective Hearing Equipment among Airport Workers. J Nat Sci Med [serial online] 2018 [cited 2019 Feb 20];1:31-5. Available from: http://www.jnsmonline.org/text.asp?2018/1/1/31/226820


  Introduction Top


Sound and noise are part of the same auditory continuum. Noise has been defined by the National Institute for Occupational Safety and Health (NIOSH) as “any unwarranted disturbance within a useful frequency band.”[1] As a result of industrialization, noise exposure in different occupations is almost inevitable. Noise has been identified as a risk factor for multiple medical conditions including hypertension, anxiety, hearing loss, and tinnitus.[2],[3] In fact, noise is responsible for 16% of hearing loss worldwide.[4] In the United States, approximately 22 million individuals are exposed to dangerous levels of noise each year.[5] Approximately 10 million individuals in the US suffer from occupational hearing loss.[6] In Saudi Arabia (Kingdom of Saudi Arabia), Ahmed et al. shown that the prevalence of hearing impairment in industrial workers exposed to noise is 39.3% in comparison to only 4.5% of nonnoise-exposed worker.[7] These levels are comparable to China where 42% of airport maintenance workers are estimated to suffer from occupational hearing loss.[8]

Tinnitus is defined as noise, regardless of its nature, perceived in the absence of external stimulus.[9] This noise may take multiple forms such as whistling, buzzing, or hissing and may be perceived as emanating from within the head or outside the body. The sound perceived may be subjective in nature, audible only by the patient, or objective, audible by both the patient and the examiner. Objective tinnitus is quite rare with a defined muscular or vascular pathology whereas subjective tinnitus is due to neurophysiological aberrations in the auditory pathway.[9]

The prevalence of tinnitus differs globally. In Japan, 11.9% of adults (45–79) are reported to have tinnitus.[10] Similarly, 10% of industrial workers in KSA were found to have tinnitus.[7] In the most recent survey, Kim et al., 2015, surveyed approximately 20,000 adults aged between 20 and 98 and identified a prevalence of 20.7%, of which 31% reported that they were annoyed by the noise during their daily life.[11] The study results showed that females were at a higher risk of developing tinnitus and that patients with depression are twice as likely to develop tinnitus when compared to the rest of the population. Other defined risk factors included smoking, dyslipidemia, age, and different systemic chronic diseases such as rheumatoid arthritis and thyroid diseases.[11]

In Saudi Arabia, only few studies have assessed the prevalence of hearing loss and tinnitus in the working population, none of which have assessed airport workers. We hope that our study can shed light on this topic in our community and provide feedback regarding possible educational programs or screening strategies, if needed, directed toward this population.


  Methods Top


Ethical statement

The study protocol was approved by the institutional review board of King Saud University. The study was conducted in accordance with the Declaration of Helsinki. Informed consent was attained from all participants before their inclusion in this study.

Study design

This was a quantitative observational cross-sectional study.

Subjects

King Khalid International Airport is the largest airport in the Kingdom of Saudi Arabia with a total of 900 airport field workers (AFWs) distributed across three departments: maintenance, transportation, and cargo and is located in the capital city, Riyadh. In this cross-sectional study, we targeted all AFWs working at King Khalid International Airport in the year 2016 to assess the prevalence of hearing loss and tinnitus and to correlate them with the use of protective hearing equipment (PHE). All AFWs included in this study have undergone a preemployment baseline audiometry screening. Inclusion criteria included all AFWs at King Khalid International Airport. Exclusion criteria included refusal to participate.

Sample size

According to the airport administration office, there were 900 AFWs (total population). Since few studies have assessed the prevalence of tinnitus among aircraft workers in the Middle East, we assumed that 50% currently suffer from tinnitus to achieve the maximum sample size. We considered a margin of error of 5%, with a 95% confidence level, using the standard sample size formula for a single proportion:

N = Z2α/2P (1 − P)/d2

N: Sample size

P: Proportion

d: Margin of error

Zα: A normal deviate reflects the Type I error and is equal to 1.96 for 95% confidence level.

Sample size was calculated to be 384.

Data collection tools

A self-administered questionnaire was used to assess the study's objectives. Due to the study's multiethnic population, both English and Arabic languages of the questionnaire were used. The questionnaire was composed of three main parts.

Part 1 assesses participants' demographics in terms of age, gender, nationality, educational status, years spent at the airport, and usage of PHE.

Part 2 of the questionnaire addresses the prevalence of tinnitus and its characteristics. The presence or absence of tinnitus was determined by the following question “In the past 12 months, have you noticed any buzzing, ringing, or any other form of noise in the absence of any external sound?” Tinnitus severity was assessed using a subjective scale of “mild,” “moderate,” or “severe” as well as its impact on sleep.

Part 3 included formal audiometric testing. The testing took place in a secluded room approximately 0.5 km from runway to minimize interfering background noise. For the purpose of this study, hearing loss was divided into low (0.5, 1, and 2 kHz) and high frequency (4 and 8 kHz). A hearing loss of mild (≥25 and ≤40 dB) corresponded to hearing difficulties between moderate (40–55 dB) and severe (>55 dB).

Statistical analysis

A pilot study was conducted on the 1st week on 10 employees to assess the clarity of the questionnaire, time needed for data analysis as well as data cleaning. Categorical variables were reported as percentage while continuous variable was reported for means and standard deviation. Chi-square test was used to compare the participants' belief regarding PHE benefits and their usage of the equipment. The results were considered statistically significant if P ≤ 0.05. SPSS software version 21.0 (Denmark) was used for further analysis of data.


  Results Top


Demographics

Three hundred airport workers responded to the survey yielding a response rate of 78%. Our population consisted of male participants exclusively as there are no female AFWs in Saudi Arabia. Participants were of Saudi nationality (68%), high-school graduates (38%), aged between 30 and 39 (37%), and current smokers (45%). The demographics are summarized in [Table 1].
Table 1: Demographics

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In regard to years spent working in the airport, 40.3% of the respondents had worked at the airport for more than 10 years, 24% of the respondents had been employed for 1–3 years, 17.3% of the respondents had worked at the airport for 4–6 years, 11.7% of the respondents had worked at the airport for 7–9 years, and only 6.7% of the respondents had worked at the airport for <1 year.

Usage of protective hearing equipment

Only 38% of surveyed sample reported using PHE during work, of whom 50% use PHE for 1–3 h/day, 27% use it for 4–6 h, 13% use it for 7–9 h and only 10% reported using PHE all throughout their work shift. Furthermore, our survey shows that only 58% of our sample believe that PHE prevents hearing loss. Only 45% believe that PHE prevents tinnitus.

Prevalence and characteristic tinnitus

Tinnitus was reported by 27% of population. In most cases, tinnitus was bilateral (61%) and did not cause any difficulties in sleep (67%). Tinnitus reportedly affected the right ear in 19% and the left ear in 22% and was bilaterally in 59%. Only 20% of those affected by tinnitus sought medical attention.

Pure-tone audiometry

In the low-frequency group (0.5, 1, 2 kHz), a total of 43 participants were found to have some degree of hearing loss, most of whom (79%) were measured at mild. In regard to high-frequency hearing loss (4 and 8 kHz), 36 participants were found to have some degree of hearing loss, most of whom (50%) were measured also at mild. Across all frequencies, 32 participants were found to have variable degree of hearing loss, most of whom (69%) were measured also at mild. These results are summarized in [Table 2].
Table 2: Audiometry results

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Possible risk factors for hearing loss were also assessed. The results of which are summarized in [Table 3].
Table 3: Possible risk factors for hearing loss

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  Discussion Top


This study represents the first study to assess the prevalence of tinnitus and hearing loss among AFWs and measure their compliance in regard to the use of PHE in Saudi Arabia and probably the Middle East. Even though in our study, we did not measure the level of noise at the airport field, based on the international and global scales of noise pollution, the maximum dose of environmental noise (140 dB) a person can receive is by being within 25 m distance from an airplane takeoff.[12] Unfortunately, few studies have been done in Saudi Arabia and the Middle East to evaluate the burden of noise-induced hearing loss (NIHL) and tinnitus in settings with high levels of noise.

Usage of protective hearing equipment

US NIOSH 1998 noted that the effective use of hearing protective devices would reduce the rate of NIHL hearing loss in noise-exposed workers.[13] Previous studies assessing the compliance to PHE among individuals working at places with high levels of noise have generally documented low usage rates.[14] Lusk et al. showed that the average usage rates of PHE among 400 construction workers ranged from 18% to 49%.[15] In the present study, although 60% of the participants believe that PHE prevents hearing loss and 45% believe that they prevent tinnitus, only 38% actually use them. Moreover, no association was found between the participants' belief regarding PHE benefits and their usage of the equipment (P = 0.373).

Prevalence and characteristic of tinnitus

Tinnitus is an early warning symptom for NIHL.[5] In a study done at South Korea by Song and Kim [16] on manufacturing workers (noise exposure group) and design workers (control group) at shipyard, tinnitus prevalence was 24.3% and 3.6%.[17] This study demonstrated the relationship between the high levels of noise and tinnitus. It is worth mentioning that the severity of hearing loss was found to be significantly higher in workers with tinnitus compared to workers without tinnitus in the aforementioned study. In our study, the prevalence of tinnitus was 27% with the majority of the participants (61%) reporting bilateral tinnitus. Conversely, a similar study done in eastern Saudi Arabia demonstrated that the prevalence of tinnitus among 269 industrial workers is 11%.[7] It included workers at steel pipes and the other manufactured air conditioning units. Tinnitus due to noise exposure is drawing less attention than NIHL. Nevertheless, the probability of tinnitus development ought to be taken into consideration in hearing preservation programs for the high association reported between noise exposure and tinnitus.[6]

Pure-tone audiometry

Occupational NIHL hearing loss occurs among individuals that are exposed to excessive amounts of noise for long durations.[18] In a study done at the Republic of China by Chen et al. on 112 airport employees, the prevalence of high-frequency hearing loss was 41.9%.[8] While at Jomo Kenyatta International Airport in Nairobi, the prevalence of NIHL was 15.3%.[17] Similarly, in the present study done at King Khalid International Airport, the prevalence of NIHL was found to be 12%. Several factors can contribute the disparity of the aforementioned results including duration of exposure to noise as well as the compliance to PHE, that is, concerning NIHL among airport workers. On the other hand, a fair percentage of studies have been published in the literature to assess NIHL among workers exposed to high levels of noise. One of which is a study done in Saudi Arabia by Ahmed et al. involving 259 industrial workers (one manufactured steel pipes and the other is air conditioning unit) which found that the prevalence of high-frequency hearing loss is 65.6%. Nevertheless, the usage of PHE or the duration of exposure to noise was not documented.[7] In addition, a periodic annual audiometric examination in Taiwan done by Wu et al. on a large number of noise-exposed workers (9535) showed that a total of 3216 (34.0%) workers were found to have NIHL.[18]

In our target population, we found that the airport administration encourages that AFWs do undergo an annual audiometric screening although there was no official surveillance system to screen for NIHL among AFWs.

The study does have some limitations. First, only one-third of the total population was included in this survey. Second, even though formal audiometric testing was conducted on the sample population, AFWs may have attempted to overstate their performance during the test or claimed to use PHE in fear of repercussions. Nevertheless, this study provides vital information for decision-makers and acts as a foundation upon which further research may be built upon.


  Conclusion Top


Even with relatively good knowledge about the importance of PHE, only few workers actually use them. Thus, frequent audiometric screening tests as well as enforcement of PHE usage by AFWs need to be introduced by airport administrations.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

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National Institute for Occupational Safety and Health (NIOSH). Noise-Induced Loss of Hearing. Cincinnati, OH: National Institute for Occupational Safety and Health; 1991. Available from: https://www.cdc.gov/niosh/docs/98-126/pdfs/98-126.pdf. [Last accessed on 2018 Feb 10].  Back to cited text no. 1
    
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Jarup L, Babisch W, Houthuijs D, Pershagen G, Katsouyanni K, Cadum E, et al. Hypertension and exposure to noise near airports: The HYENA study. Environ Health Perspect 2008;116:329-33.  Back to cited text no. 2
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Beutel ME, Jünger C, Klein EM, Wild P, Lackner K, Blettner M, et al. Noise annoyance is associated with depression and anxiety in the general population- the contribution of aircraft noise. PLoS One 2016;11:e0155357.  Back to cited text no. 3
    
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Tak S, Davis RR, Calvert GM. Exposure to hazardous workplace noise and use of hearing protection devices among US workers – NHANES, 1999-2004. Am J Ind Med 2009;52:358-71.  Back to cited text no. 4
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Nelson DI, Nelson RY, Concha-Barrientos M, Fingerhut M. The global burden of occupational noise-induced hearing loss. Am J Ind Med 2005;48:446-58.  Back to cited text no. 5
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Centre for Disease Control. Available from: http://www.cdc.gov/niosh/topics/noise/stats.html. [Last accessed on 2017 Feb 10].  Back to cited text no. 6
    
7.
Ahmed HO, Dennis JH, Badran O, Ismail M, Ballal SG, Ashoor A, et al. Occupational noise exposure and hearing loss of workers in two plants in Eastern Saudi Arabia. Ann Occup Hyg 2001;45:371-80.  Back to cited text no. 7
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Chen TJ, Chiang HC, Chen SS. Effects of aircraft noise on hearing and auditory pathway function of airport employees. J Occup Med 1992;34:613-9.  Back to cited text no. 8
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Han BI, Lee HW, Kim TY, Lim JS, Shin KS. Tinnitus: Characteristics, causes, mechanisms, and treatments. J Clin Neurol 2009;5:11-9.  Back to cited text no. 9
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Fujii K, Nagata C, Nakamura K, Kawachi T, Takatsuka N, Oba S, et al. Prevalence of tinnitus in community-dwelling Japanese adults. J Epidemiol 2011;21:299-304.  Back to cited text no. 10
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Kim HJ, Lee HJ, An SY, Sim S, Park B, Kim SW, et al. Analysis of the prevalence and associated risk factors of tinnitus in adults. PLoS One 2015;10:e0127578.  Back to cited text no. 11
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Yuen FK. A vision of the environmental and occupational noise pollution in Malaysia. Noise Health 2014;16:427-36.  Back to cited text no. 12
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13.
National Institute for Occupational Safety and Health (NIOSH). Criteria for a Recommended Standard: Occupational Noise Exposure. Revised Criteria. Cincinnati: National Institute for Occupational Safety and Health; 1998. Available from: http://www.cdc.gov/niosh/98–126.html. [Last accessed on 2018 Feb 02].  Back to cited text no. 13
    
14.
Edelson J, Neitzel R, Meischke H, Daniell W, Sheppard L, Stover B, et al. Predictors of hearing protection use in construction workers. Ann Occup Hyg 2009;53:605-15.  Back to cited text no. 14
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Lusk SL, Kerr MJ, Kauffman SA. Use of hearing protection and perceptions of noise exposure and hearing loss among construction workers. Am Ind Hyg Assoc J 1998;59:466-70.  Back to cited text no. 15
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Song JB, Kim BK. Prevalence and characteristics of tinnitus in noise exposed workers. Occup Health 2002;6:16-28.  Back to cited text no. 16
    
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Anino JO, Afullo A, Otieno F. Occupational noise-induced hearing loss among workers at Jomo Kenyatta international airport, Nairobi. East Afr Med J 2010;87:49-57.  Back to cited text no. 17
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Wu TN, Liou SH, Shen CY, Hsu CC, Chao SL, Wang JH, et al. Surveillance of noise-induced hearing loss in Taiwan, ROC: A report of the PRESS-NHL results. Prev Med 1998;27:65-9.  Back to cited text no. 18
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    Tables

  [Table 1], [Table 2], [Table 3]



 

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