Article
Some health effects of aircraft noise with special reference to shift work
Toxicology and Industrial Health 1–7 © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0748233713518602 tih.sagepub.com
Sanaa A M Rizk, Nevin E Sharaf, Heba Mahdy-Abdallah and Khalid S Abd ElGelil Abstract Background: Aircraft noise is an environmental stressor. A positive relationship exists between noise and high blood pressure. Shift work is an additional hazardous working condition with negative effect on the behavior attitude of workers. Objective: This study aimed at investigating some health hazards for shift work on workers at Cairo International Airport (CIA), Egypt, as a strategic work place, with more than one stressor. Subjects and Methods: Assessment of noise effects were carried out in four working sites at the airport besides control sites. The average noise level in the exposure sites was 106.5 dB compared with 54 dB at the control sites. The study comprised a group of 200 male workers exposed to aircraft noise and 110 male workers not exposed to noise as control group. All workers had full general medical examination after filling specially formulated questionnaire. Hearing impairment, raised blood pressure, headaches, disturbed sleep, and symptoms of anxiety were more prominent among the exposed workers than the control. Symptoms of upper respiratory tract were reported among night shifters of both groups with high tendency for smoking. Thus, night-shift workers at CIA work under more than one stressor. Hypertension and smoking might act as intermediate factors on the causal pathway of complaints, making aircraft noise and night shift acting as two synergistic stressors. Airport workers are in need for aggressive hearing conservation programs. Organization of the working hours schedule is mandatory to avoid excessive noise exposure. Keywords Air craft noise, shift work, health effects, smoking, stress
Introduction Environmental noise, irrespective of its source, remains a key issue in most countries. Noise, defined as ‘unwanted sound’ is perceived as an environmental stressor and nuisance. The predominant health effect of noise is an auditory damage that induces hearing loss. Besides the auditory noise effect, attention must also be paid to the nonauditory effects of noise. Nonauditory effects of noise can be defined as ‘‘all those effects on health and well-being which are caused by exposure to noise’’ (Stansfeld and Matheson, 2003). Nonauditory effects of noise appear to occur at levels far below those required to damage the hearing organ (Babisch, 2004). Noise pollution can cause annoyance and aggression, hypertension, high stress levels, tinnitus, hearing loss, sleep disturbances, and other harmful effects (Passchier-Vermeer and Passchier, 2000). Furthermore, stress and hypertension are the leading causes
to health problems, whereas tinnitus can lead to forgetfulness, severe depression, and at times panic attacks (Kryter, 2009). Huss et al. (2010) found that people exposed to high levels of noise from aircraft were at increased risk of dying from myocardial infarction. Shift work generally is defined as work hours that are scheduled outside of daylight. Shift work disrupts the synchronous relationship between the body’s internal clock and the environment (Berger and Hobbs, 2006). The disruption often results in problems such Department of Environmental and Occupational Medicine, National Research Centre, Cairo, Egypt Corresponding author: Heba Mahdy-Abdallah, Department of Environmental and Occupational Medicine, National Research Center, El Behouth Street, Cairo 12622, Egypt. Email: [email protected]
Downloaded from tih.sagepub.com at Monash University on November 18, 2015
2
Toxicology and Industrial Health
Table 1. Comparison between noise levels at exposure and control sites.a Noise level (dB)
a
Exposure sites Mean + SD
Control sites Mean + SD
106.5 + 2.5
54.0 + 1.5
p < 0.001.
as disruption of biological rhythms, with a negative influence on performance efficiency, health, and social well-being. Deterioration of health can manifest in the short-term as sleep disorders (Admi et al., 2008), jet-lag syndrome, and increased risk for errors and accidents at work as compared to those workers on a straight daytime shift schedule (Fido and Ghali, 2008). In the long-term, there is an increased risk of high blood pressure, colorectal cancer (Schernhammer et al., 2003), psychoneurotic, and cardiovascular diseases (Costa, 2003). Harada et al. (2005) reveal that the three-shift system of employment increases work-related stress and job control is low among shift workers. International Labour Organization and European Council directive have recently stressed the need for the careful organization of shift and night work, and the protection of shift workers (European Council Directive, 2003; ILO, 1995). This study was aimed at investigating some health hazards for shift work on workers at Cairo International Airport (CIA), Egypt, as a strategic work place, with more than one stressor.
Methodology The four sites of noise exposure were the runways, the luggage section, the workshop for maintenance, and ground assistants of other vehicles in the CIA. The control sites consisted of four closed offices for services related to the CIA and classified as quite areas. A precision sound level meter (type 2232; Bruel and Kjaer, Denmark) was used to measure noise levels at the sites included in the study. It is equipped with a high-sensitivity ½ inch diameter condenser microphone. The sound level meter was calibrated using calibrator type 4230. This was achieved by adjustment of sensitivity potentiometer on the sound level meter. However, the detailed environmental noise survey is a separate subject for the engineering team (under publication). The study population consisted of all workers at the selected sites (200 male workers) employed at CIA.
They were all exposed to aircraft noise for 8 h daily for 6 days/week. A control group of unexposed workers (110 male workers), matched for age and socioeconomic status underwent the same investigations. Consents were obtained from all the participants prior to the study. The two groups of the study were subdivided into two groups namely day and night shift. Detailed personal and occupational histories were taken with special reference to smoking habits, current complaints such as ear pain, tinnitus, vertigo, discharge, feeling of diminished hearing acuity, receiving ototoxic drugs, difficulty of concentration during work and subjective feeling toward noise, headaches, sleep disturbance, irritability, and symptoms of upper respiratory disease and symptoms of anxiety. A special stress sheet Shaheen and Rakhawy (1971) was filled for every worker by the same investigator in order to avoid personal errors. The stress scale was used to detect the state of anxiety expressed by the subject under investigation. The questionnaire used is an Arabic version of the middle six questionnaire, consisting of 30 questions and were self-answered by the workers. The score was divided into (0–15) for low and (16–30) for severe stress. After filling up the specially formulated questionnaire, a general medical examination was carried out with special stress on blood pressure measurement using an ordinary mercury sphygmomanometer. Blood pressure was estimated in sitting position after 15 min at rest, 140 mm Hg systolic or 90 mm Hg diastolic or both were considered hypertensive (Black and Yi, 1996). Hearing impairment was considered by subject complaints. Results were tabulated and differences between means and proportions were tested for significance using standard statistical methods. Frequencies for each response were determined and subsequently computed into percentages. Student’s t tests were used to compare the means of two continuous variables. 2 test was used for comparison of qualitative data. Statistical significance was set at p 0.05.
Results Results of this study showed a statistically significant difference between the average noise level at the working sites and the control ones (Table 1). There was no statistically significant difference between studied groups concerning their ages p > 0.05. When the duration of employment was assessed between groups, it was observed that the duration of employment is not
Downloaded from tih.sagepub.com at Monash University on November 18, 2015
Rizk et al.
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Table 2. Smoking habits among the studied population. Exposed group (n ¼ 200) Groups Smoking habits Smokers no (%) Nonsmokers no (%)
Control group (n ¼ 110)
Day shift group (n ¼ 120)
Night shift group (n ¼ 80)
Day shift group (n ¼ 70)
Night shift group (n ¼ 40)
50 (41.6%) 70 (58.4%)
40 (50%) 40 (50%)
10 (14.2%) 60 (85.7%)
10 (25%) 30 (75%)
Table 3. Smoking habits among day shifters.
Groups Smoking habits Smokers no (%) a
Exposed group (n ¼ 200)
Control group (n ¼ 110)
Day shift group (n ¼ 120)
Day shift group (n ¼ 70)
p Value
50 (41.6%)
10 (14.2%)
Some health effects of aircraft noise with special reference to shift work
Toxicology and Industrial Health 1–7 © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0748233713518602 tih.sagepub.com
Sanaa A M Rizk, Nevin E Sharaf, Heba Mahdy-Abdallah and Khalid S Abd ElGelil Abstract Background: Aircraft noise is an environmental stressor. A positive relationship exists between noise and high blood pressure. Shift work is an additional hazardous working condition with negative effect on the behavior attitude of workers. Objective: This study aimed at investigating some health hazards for shift work on workers at Cairo International Airport (CIA), Egypt, as a strategic work place, with more than one stressor. Subjects and Methods: Assessment of noise effects were carried out in four working sites at the airport besides control sites. The average noise level in the exposure sites was 106.5 dB compared with 54 dB at the control sites. The study comprised a group of 200 male workers exposed to aircraft noise and 110 male workers not exposed to noise as control group. All workers had full general medical examination after filling specially formulated questionnaire. Hearing impairment, raised blood pressure, headaches, disturbed sleep, and symptoms of anxiety were more prominent among the exposed workers than the control. Symptoms of upper respiratory tract were reported among night shifters of both groups with high tendency for smoking. Thus, night-shift workers at CIA work under more than one stressor. Hypertension and smoking might act as intermediate factors on the causal pathway of complaints, making aircraft noise and night shift acting as two synergistic stressors. Airport workers are in need for aggressive hearing conservation programs. Organization of the working hours schedule is mandatory to avoid excessive noise exposure. Keywords Air craft noise, shift work, health effects, smoking, stress
Introduction Environmental noise, irrespective of its source, remains a key issue in most countries. Noise, defined as ‘unwanted sound’ is perceived as an environmental stressor and nuisance. The predominant health effect of noise is an auditory damage that induces hearing loss. Besides the auditory noise effect, attention must also be paid to the nonauditory effects of noise. Nonauditory effects of noise can be defined as ‘‘all those effects on health and well-being which are caused by exposure to noise’’ (Stansfeld and Matheson, 2003). Nonauditory effects of noise appear to occur at levels far below those required to damage the hearing organ (Babisch, 2004). Noise pollution can cause annoyance and aggression, hypertension, high stress levels, tinnitus, hearing loss, sleep disturbances, and other harmful effects (Passchier-Vermeer and Passchier, 2000). Furthermore, stress and hypertension are the leading causes
to health problems, whereas tinnitus can lead to forgetfulness, severe depression, and at times panic attacks (Kryter, 2009). Huss et al. (2010) found that people exposed to high levels of noise from aircraft were at increased risk of dying from myocardial infarction. Shift work generally is defined as work hours that are scheduled outside of daylight. Shift work disrupts the synchronous relationship between the body’s internal clock and the environment (Berger and Hobbs, 2006). The disruption often results in problems such Department of Environmental and Occupational Medicine, National Research Centre, Cairo, Egypt Corresponding author: Heba Mahdy-Abdallah, Department of Environmental and Occupational Medicine, National Research Center, El Behouth Street, Cairo 12622, Egypt. Email: [email protected]
Downloaded from tih.sagepub.com at Monash University on November 18, 2015
2
Toxicology and Industrial Health
Table 1. Comparison between noise levels at exposure and control sites.a Noise level (dB)
a
Exposure sites Mean + SD
Control sites Mean + SD
106.5 + 2.5
54.0 + 1.5
p < 0.001.
as disruption of biological rhythms, with a negative influence on performance efficiency, health, and social well-being. Deterioration of health can manifest in the short-term as sleep disorders (Admi et al., 2008), jet-lag syndrome, and increased risk for errors and accidents at work as compared to those workers on a straight daytime shift schedule (Fido and Ghali, 2008). In the long-term, there is an increased risk of high blood pressure, colorectal cancer (Schernhammer et al., 2003), psychoneurotic, and cardiovascular diseases (Costa, 2003). Harada et al. (2005) reveal that the three-shift system of employment increases work-related stress and job control is low among shift workers. International Labour Organization and European Council directive have recently stressed the need for the careful organization of shift and night work, and the protection of shift workers (European Council Directive, 2003; ILO, 1995). This study was aimed at investigating some health hazards for shift work on workers at Cairo International Airport (CIA), Egypt, as a strategic work place, with more than one stressor.
Methodology The four sites of noise exposure were the runways, the luggage section, the workshop for maintenance, and ground assistants of other vehicles in the CIA. The control sites consisted of four closed offices for services related to the CIA and classified as quite areas. A precision sound level meter (type 2232; Bruel and Kjaer, Denmark) was used to measure noise levels at the sites included in the study. It is equipped with a high-sensitivity ½ inch diameter condenser microphone. The sound level meter was calibrated using calibrator type 4230. This was achieved by adjustment of sensitivity potentiometer on the sound level meter. However, the detailed environmental noise survey is a separate subject for the engineering team (under publication). The study population consisted of all workers at the selected sites (200 male workers) employed at CIA.
They were all exposed to aircraft noise for 8 h daily for 6 days/week. A control group of unexposed workers (110 male workers), matched for age and socioeconomic status underwent the same investigations. Consents were obtained from all the participants prior to the study. The two groups of the study were subdivided into two groups namely day and night shift. Detailed personal and occupational histories were taken with special reference to smoking habits, current complaints such as ear pain, tinnitus, vertigo, discharge, feeling of diminished hearing acuity, receiving ototoxic drugs, difficulty of concentration during work and subjective feeling toward noise, headaches, sleep disturbance, irritability, and symptoms of upper respiratory disease and symptoms of anxiety. A special stress sheet Shaheen and Rakhawy (1971) was filled for every worker by the same investigator in order to avoid personal errors. The stress scale was used to detect the state of anxiety expressed by the subject under investigation. The questionnaire used is an Arabic version of the middle six questionnaire, consisting of 30 questions and were self-answered by the workers. The score was divided into (0–15) for low and (16–30) for severe stress. After filling up the specially formulated questionnaire, a general medical examination was carried out with special stress on blood pressure measurement using an ordinary mercury sphygmomanometer. Blood pressure was estimated in sitting position after 15 min at rest, 140 mm Hg systolic or 90 mm Hg diastolic or both were considered hypertensive (Black and Yi, 1996). Hearing impairment was considered by subject complaints. Results were tabulated and differences between means and proportions were tested for significance using standard statistical methods. Frequencies for each response were determined and subsequently computed into percentages. Student’s t tests were used to compare the means of two continuous variables. 2 test was used for comparison of qualitative data. Statistical significance was set at p 0.05.
Results Results of this study showed a statistically significant difference between the average noise level at the working sites and the control ones (Table 1). There was no statistically significant difference between studied groups concerning their ages p > 0.05. When the duration of employment was assessed between groups, it was observed that the duration of employment is not
Downloaded from tih.sagepub.com at Monash University on November 18, 2015
Rizk et al.
3
Table 2. Smoking habits among the studied population. Exposed group (n ¼ 200) Groups Smoking habits Smokers no (%) Nonsmokers no (%)
Control group (n ¼ 110)
Day shift group (n ¼ 120)
Night shift group (n ¼ 80)
Day shift group (n ¼ 70)
Night shift group (n ¼ 40)
50 (41.6%) 70 (58.4%)
40 (50%) 40 (50%)
10 (14.2%) 60 (85.7%)
10 (25%) 30 (75%)
Table 3. Smoking habits among day shifters.
Groups Smoking habits Smokers no (%) a
Exposed group (n ¼ 200)
Control group (n ¼ 110)
Day shift group (n ¼ 120)
Day shift group (n ¼ 70)
p Value
50 (41.6%)
10 (14.2%)
