Journal of Health and Safety at Work

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Introduction: According to the literature, a large number of people working in industries and service providing personnel, such as firefighters, physicians, and nurses, are shift workers. The spread of shift working in industrial societies and the incidence of the problems resulting from shift working have caused the researchers to conduct studies on this issue. The present study also aimed to investigate melatonin and cortisol circadian rhythms in the security guards of Shiraz University of Medical Sciences, Shiraz, Iran.

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Material and Method: The present study was conducted among 20 security guards of Shiraz University of Medical Sciences. In order to collect the required data, blood samples were taken from the participants in different times of the day (1, 4, 7, 10, 13, 16, 19, and 22) and cortisol and melatonin levels were determined using radioimmunoassay and enzyme immunoassay techniques, respectively. Then, the data were entered into the SPSS statistical software (v. 16.0) and analyzed using One-Way ANOVA.

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Result: The results showed that as the intensity of light increased during night time, the level of plasma cortisol increased, as well. Besides, no statistically significant difference was found between the plasma cortisol levels in natural light and 4500-lux light. On the other hand, a significant difference was observed between the level of plasma cortisol in natural light and 9000-lux light as well as 4500- and 9000-lux lights. The study findings also showed that as the intensity of light increased at night, the level of plasma melatonin decreased. In addition, a statistically significant difference was found between the plasma melatonin levels in natural light and 4500-lux light. Nevertheless, no significant difference was observed between the plasma melatonin levels in natural light and 9000-lux light as well as 4500- and 9000-lux lights.

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Conclusion: The present study aimed to investigate the subsequences of shift working in the security guards of Shiraz University of Medical Sciences and showed that occupational exposure to bright light could affect some biological markers, such as melatonin and cortisol secretion.

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Introduction: This paper aims to explore the main effect of night shift rotation speed on the pattern of melatonin secretion and the sleepiness, among control room operators (CORs) in a petrochemical industry
Material and method: In this study, 60 CORs operators within two different patterns, including 7 nights and 3 nights shift works were selected from a petrochemical industry to investigate the influence of rotation speed on their melatonin secretion and the sleepiness pattern. Thus, melatonin was sampled from saliva, and the sleepiness and sleep quality were assessed using Karolinska Sleepiness Scale (KSS) index. Data analysis was carried out using spss18, Chi square, t-test, and GLM model.
Results: Melatonin values and their general changes during shift were noticeably different in two proposed patterns (P <0.05). The sleepiness index was significantly different only at 3:00 in both patterns, whereas the interaction of light and caffeine on both melatonin changes and sleepiness was not significant (P <0.05). Moreover, a significant difference was observed between the process of melatonin changes and sleepiness in the two studied patterns (P <0.05).
Conclusion: Adopting slower shift schedules rotations would be more appropriate, from the viewpoints of the importance of alertness and performance for human error prevention, among people working in serious worksites such as control rooms.

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Introduction: Damage to occupational health is one of the major challenges in the industry. Various studies have shown that productivity in industries has a significant relationship with occupational health. In addition, employee’s health in the workplace can be affected by a variety of variables i.e., job stress, job satisfaction, and work in unconventional shifts. Therefore, the purpose of this study was to evaluate the causal relationships of shift work, job stress, job satisfaction with the occupational health level in a petrochemical industry.
Material and Methods: This cross-sectional study was implemented in 2017. The study sample consisted of 20 HSE experts selected using purposeful judgment sampling. A 4×4 matrix questionnaire consisting of four main parameters i.e., shift work, job stress and job satisfaction with occupational health level, was used for data acquisition. Data analysis was done using MATLAB software and Fuzzy DEMATEL method. Also, for each variable, two key values of D+R and D-R were calculated. These values show the degree of interaction and the type of interaction of the variable with other variables, respectively.
Results: Sixty percent of the experts participating in this study were male and 40.0% were female. Only 10.0% of the participants had a PhD degree. In addition, the mean age and the mean work experience of the subjects were 39.64±9.34 and 10.22±7.10 years, respectively. The parameters of shift work and job satisfaction were identified as an effective factor due to the positive values of D-R while occupational health variable with negative value of D-R, was considered as an affected factor. In addition, these results showed that the effect of these parameters on health is different with both direct and indirect mechanisms.
Conclusion: Using the Fuzzy DEMATEL method, our findings indicated that occupational health in the large industries can be influenced by different parameters with different sizes. Considering the interactions among these parameters in health analysis and the affecting factors, therefore, is very important. So, the health level in challenging industrial environment such as petrochemical industries can be affected by shift work as a root cause. This root cause, along with job satisfaction, has a significant effect on increasing stress levels and reducing health levels. Accordingly, any action to increase the health level should focus on improving shift patterns and increasing the level of job satisfaction of employees as a pivotal root and affecting causes on health level.

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Introduction: Shift work combined with the nature of duty in occupations such as nursing can lead to the spread of psychological consequences and disorders in nurses. The aim of this study was investigating the cognitive and psycho-social consequences associated with shift work in nurses.
Material and Methods: This study was performed in 7 hospitals in 2023. The study population was 636 nurses. Data collection tool in this study was part of a comprehensive questionnaire that translated and modified by Choobineh et al. The data were analyzed using IBM SPSS software v. 22.0, and significance level in this study was considered 0.05.
Results: Out of 636 studied nurses, 474 were shift workers and 162 were day workers. The means of age and work experience of the study population were 37.26±5.25 years and 11.60±4.78 years, respectively. The results showed that the prevalence of psychological consequences in the shift workers group was significantly more than day work nurses (p<0.05). The highest prevalence of cognitive and psycho-social consequences in shift work nurses were related to fatigue (39.66%), insomnia (36.08) and decreased sleep quality (35.44%), respectively.
Conclusion: The findings of this study indicated that the parameters of the shift work system, working hours per week, education and hospital ward are the most important factors affecting the prevalence of cognitive and psycho-social consequences and sleep disorders in the nurses. Therefore, it is suggested that a separate program should be designed and implemented for each hospital ward to control and manage the psychological consequences associated with shift work in nurses.