Journal of Health and Safety at Work

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Introduction: Noise exposure is known as a risk factor for hearing loss and one of its effects is noise-induced stress. Cortisol, as stress hormone- is used in noise-induced stress assessments studies. The aims of this study were:(1) measuring and comparing saliva cortisol concentrations in the morning and evening in normal work day and rest day between two groups, (2) assessing the relationship between industrial noise exposure and salivary cortisol concentrations between two groups.

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Material and Method: Two hundred male workers (100 industrial and 100 office employees) participated in this study. Morning and evening saliva samples were collected at 7 a.m and 4 p.m, respectively. Noise exposure levels were assessed by sound level meter and noise dosimeter. All measurements occurred in two days: one in rest day and other in working day. Descriptive statistics, paired and independent sample t-test and regression analysis were used as statistical tools with α=0.05.

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Result: On the rest day and work day, between morning salivary cortisol was no significant difference in two groups. Comparing evening cortisol concentrations in work day with rest day a significant difference was observed, in worker group, but it was not significant in the other group. The evening cortisol in the working day in was significantly higher among workers than officers.

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Conclusion: This study revealed that industrial noise exposure with levels higher than 80 dBA has a significant effect on salivary cortisol elevation.

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Introduction: Installation of wind turbines in residential areas due to their unique sound characteristics may cause noise annoyance. Noise annoyance can increase the risk of health problems and sleep disturbance. Thus, this study was conducted to assess the effect of wind turbine noise annoyance on sleep disturbance among the Manjil wind farm workers.

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Material and Method: All the Manjil wind farm workers have been divided into three groups according to their noise exposure levels, including maintenance, security, and administrative workers. The equivalent A weighted noise levels were measured for each of the study working groups, using ISO 9612 standard method. Information related to the noise annoyance and sleep disturbance were determined by ISO15666 standard and the Epworth Sleepiness Scale, respectively. Data were analyzed using R software.

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Result: Findings of ANOVA and Kruskal-Wallis statistical tests showed that noise annoyance and sleep disturbance were statistically different among workers with various occupational, age, and work experience groups. Also, noise annoyance and sleep disturbance had a significant association in a way that regardless of the effects of other variables, it can be stated that for every one unit increase in noise annoyance, 0.26 units will be added to the amount of sleep disturbance.

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Conclusion: In this study, workers with more wind turbine noise annoyance had more sleep disturbance. Therefore, in addition to the direct effects of noise on sleep disturbance, it can indirectly exacerbate sleep disturbances.

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Introduction: Chronic occupational noise exposure may constitute a risk factor for cardiovascular disease for workers. The aim of this study was to investigate the relationship between occupational noise exposure and noise annoyance with blood pressure, serum cholesterol and triglyceride levels in workers of a textile industry.

Material and Method: This cross-sectional study was carried out among 220 employees of Savadkouh textile industry complex in Mazandaran province, Iran in 2017. To achieve the study objectives, the 8 -hour equivalent sound exposure level was measured and the cumulative noise exposure was calculated. Based on noise exposure level, workers were divided into control and case groups. Then, blood pressure was measured and blood samples were collected from each individual for determination of the serum cholesterol and triglyceride levels and they were transfered to the laboratory for further analysis. The noise annoyance scale and socio-demographic questionnaire were used to collect noise annoyance and other background and demographic information, respectively. Finally, Paired t-test, one-way ANOVA and multivariate regression were used to study the relationship between variables using SPSS Version 20.

Result: In total, 159 workers participated in this study considering the inclusion and exclusion criteria. Eighty-three participants were exposed to more than or equal to 85 dBA, and 76 person were exposed to less than 85 dBA noise level, respectively. The results showed that mean blood pressure and cholesterol were significantly different between the control and case groups (P-value< 0.05). Based on multivariate regression results, noise exposure, cumulative noise exposure (CNE) and noise annoyance had a significant effect on blood pressure (P-value< 0.001).  Cholesterol was also significantly affected by noise exposure and noise annoyance (P-value< 0.005).

Conclusion: Based on the results of current study, noise can be considered as a risk factor for cardiovascular disease ampong workers. Actually, high intensity noise affect serum cholesterol and blood pressure directly, and may do indirectly by causing noise annoyance which acts as a mediator. Therefore, it seems necessary to conduct a controlled cohort study to investigating the interactions among whole variables of interest.

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Introduction: Previous studies have been conducted on the effects of exposure of industrial workers to high levels of noise and their association with mental health or exposure of people to harmful levels of environmental noise. In this study, we investigated the association between moderate noise levels and the symptoms of depression, anxiety, and stress in non-industrial workers.
Material and Methods: This study is a Cross-Sectional study that was conducted using the enrollment phase data of the Tehran University of Medical Sciences Cohort (TEC) study. The study population consisted of 3899 workers of Tehran University of Medical Sciences who were employed in seven occupational groups of the university, Office Workers, Healthcare workers, technical personnel, services workers, security guards, and radiology-radiation units. Exposure to moderate noise level was examined using the Leq10min index, and the Depression Anxiety Stress Scales were examined on the mentioned population by DASS-42 questionnaires.
Results: The results showed that the prevalence of severe to very severe symptoms of depression, anxiety and stress were 8.2, 7.9, and 11% respectively. Also, it was observed that 14.5% of the participants of the study were exposed to noises of more than 70 dB(A). Furthermore, the results indicated that the highest average noise was equal to 71.3 dB(A) for the technical staff group, and the lowest value with an average of 59.1 dB(A) was recorded for the office workers group. The symptoms of severe to very severe depression was associated with exposure to noises above 70 dB(A) (OR:5.22) anxiety (OR:1.16), stress (OR:1.17) and socioeconomic status (OR:1.84). The severe to very severe anxiety was associated with stress (OR: 1.25). On the other hand, the symptoms of severe to very severe stress was associated with variables of age (OR:0.99), gender (OR:0.46), socioeconomic status (OR:1.52), having job management position (OR:0.81) and having healthcare working job (OR:0.65).
Conclusion: Regarding the obtained results of the present study, it was concluded that exposure to moderate noise levels had positive and significant association with depression in non-industrial workers. In non-industrial work environments, exposure to moderate noise levels is and can be independently associated with depression.

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Introduction: Workplace noise is one of the main sources of health problems. Noise can have many direct and indirect effects that threaten human health in various ways. The aim of this study was to investigate the effect of noise annoyance on anxiety among workers.
Material and Methods: This study included 60 workers from a carton manufacturing company, who were divided into two groups based on noise exposure: exposure (noise level more than 85 dB) and control (noise level less than 85 dB). Noise exposure of the individuals at the workplace was measured in accordance with ISO 9612:2009 standard and using a TES-1354 dosimeter. Anxiety levels were assessed using the Spielberger Anxiety Inventory (STAI), and noise annoyance was measured using a 100-point visual analog scale. Statistical analysis was performed using STATA statistical software. 
Results: The mean age and work experience of the study subjects were 35.78 and 10.78 years, respectively. The results indicated a statistically significant difference (P-value < 0.05) in the mean noise annoyance scores between the groups. The mean noise annoyance score in the exposed group was significantly higher (88.03) than in the non-exposed group (47.6). The average anxiety scores in the exposure and control groups were 106.81 and 101.6, respectively. In addition, regression analysis showed that each unit increase in noise annoyance level resulted in a 1.08-fold increase in anxiety in the exposed group.
Conclusion: Noise annoyance is often the most common psychological response to noise exposure and can be a predictor of many mental disorders or illnesses, including anxiety. Therefore, it is important to implement control measures to reduce noise exposure in the workplace.