IRAN OCCUPATIONAL HEALTH JOURNAL
Year:2019 | Volume:16 | Issue:3|Papers Count:8

Background and aims: Sickness absence is a major socio-economic problem imposing a huge amount of cost to societies. Absence from work entails complex conditions and multifactorial etiology. There are various occupational and personal factors contributing to the incidence of sickness absence. Long-term sickness absence compels the employer to reassign the tasks to other workers or replace the absent worker. In this light, it is essential to identify the workers at risk of sickness absence, particularly long-term sickness absence. The work ability index (WAI) can serve research purposes and clinical assessments in occupational health, aimed at evaluating the ability to work during occupational health examinations and environmental monitoring. Given the importance of sickness absence and identification of workers at risk of absence from work, this study attempted to evaluate influence of short-term and long-term sickness absence on work ability index. Methods: This cross-sectional study was conducted on 806 car accessories production company workers. The questionnaires were handed to workers with, at a minimum, one year of employment volunteering in the research project. Certain occupational data concerning date of employment, working location and shift work status were obtained from the Personnel Selection Department. Informed consent was obtained from all individual participants included in the study. The sickness absence data were extracted from the HSE of the factory, containing the number of days and episodes of sickness absence. Absence from work was divided into two categories: short-term (<3day) and long-term (≥ 3days) sickness absence. A questionnaire completed by the workers was employed to collect data on demographic information including age, marital status, education level, smoker/non-smoker and BMI. In terms of age, the subjects were divided into two categories of less than 35 years old and equal or greater than 35 years old. The work ability among the workers was measured through the Work Ability Index questionnaire comprising 7 items: 1) current work ability compared with the lifetime best, 2) work ability in relation to the demands of the job 3) number of current diseases diagnosed by physician, 4) estimated work impairment due to diseases, 5) sick leave during the past year (12 months), 6) work ability in the forthcoming two years, and 7, and 7) mental resources. In all items, the highest scores of WAI represent the best work ability. The Chi-square test was used to compare the qualitative variables and the logistic regression analysis to determine the relationship between WAI and sickness absence. In all tests, the significance level was considered 0. 05. Results: Of 956 workers, 850 responded to the questionnaire (response rate of 88. 91%). Having applied the exclusions criteria, a total of 806 subjects were analyzed. All the subjects were male ranging from 21 to 63 years old with an average age of 35. 04± 6. 84 years. Moreover, 75. 7% of the subjects had shift work, and 76. 4% were blue collar. Analysis of data on sickness absence revealed that 55. 3% of subjects had a record of absence from work, of whom 61. 9% were short-term (<3 days) and 38. 1% long-term (≥ 3 days). The mean WAI score was 42. 19± 4. 37. In comparison of the two groups with and without sickness absence in terms of demographic characteristics, the mean age was 35. 65± 7. 32 for the non-absence group and 34. 55± 6. 40 for the absence group, indicating a statistically significant difference (p=0. 025). Furthermore, the mean BMI was 25. 90± 2. 78 in the non-absence group, higher than 25. 35± 2. 62 in the absence group (p=0. 004). The Chi-square test suggested that shift workers and blue collars had more frequent absence from work with (OR=1. 651 and p=0. 002) and (OR=2. 256 and p<0. 001), respectively. Short-term sickness absence was higher among shift workers (OR=1. 84 and p=0. 011). Moreover, the long-term absence was more frequent among smokers while short-term absence was more frequent among nonsmokers (OR=2. 12 and p=0. 002). The two groups with short and long-term absences, however, indicated no significant differences in terms of age and BMI. The mean WAI was 41. 0 ± 4. 8 in smokers and 42. 4± 4. 2 in non-smokers, indicating a statistically significant difference (p<0. 001). The mean (SD) of WAI scores in workers with short-term, long-term and total sickness absence were 41. 97(3. 97) 40. 62(5. 30) and 41. 45(4. 56), respectively; and in workers without any sickness absence was 43. 09(3. 93). The WAI of workers without sickness absence was higher than that of workers with sickness absence (OR=2. 79; 95% CI=1. 63-4. 76 and P-value<0. 001); and was higher in workers with short-term sickness absence than those with long-term sickness absence (OR=3. 06; 95% CI=1. 74-5. 36 and p<0. 001). After adjusting the effects of other factors, there was a correlation between WAI and sickness absence in the two groups with and without absences as well as workers with short and long term sickness absence (p<0. 001 and 0. 019, respectively). In comparison of the WAI subcategories between the absence and non-absence groups, "the current work ability compared with life time best" was greater in the non-absence subjects than the absence subjects (p=0. 013). Moreover, it was greater in the short-term absence subjects than the longterm absence subjects (p=0. 045). The analytical results of chi-square test showed that WAI was significantly higher in the non-absence group than the absence group. In other words, sickness absence was considerably lower in the group with high work ability (OR=2. 790; CI=1. 63-4. 76 and p<0. 001). Concerning the subjects with a history of sickness absence, the WAI was greater in the short-term absence group than the long-term absence group (OR=3. 060; CI=1. 74-5. 36 and p<0. 001). Conclusion: This study assessed the relationship between WAI scores, sickness absence and the role of individual and occupational factors among the workers involved in the Iranian automotive industry. There was a significant relationship found between WAI and sickness absence that was consistent with the results of other studies. Sickness absence in the blue collar group and shift workers was higher. This finding can be explained by the fact that white collars are not in contact with the production-related hazards and are less likely to absent from work. Similarly, shift work disrupts the circadian rhythm, leading to morbidity and risk of many diseases. The overall WAI score was greater in non-absence subjects than absence subjects. Moreover, it was lower in long-term absence subjects than short-term absence subjects. Comparing the two groups with a history of short and long-term absences, it was revealed that short-term absence was more frequent among the shift workers. This finding can be explained by the fact that sick or non-healthy individuals are more likely to prefer jobs not requiring work shift. The lower WAI scores increased the episodes and lengths of sickness absence. The findings suggested that WAI can be correlated with shortterm and long-term Sickness absence and can be employed as a simple and useful tool to identify workers at risk of sickness absence.

and aims: Parks are a place for children's play and activity. Safety of these social environments is important in environmental planning. It is necessary to provide quality and sustainable conditions for park playgrounds and equipments to improve the safety and health of children. In general, the play equipments standards are formulated and published by the Institute of Standards & Industrial Research of Iran and the manufacturers are notified and required to design children's play equipment according to the most up-to-date standards. Since the municipality is responsible for purchasing, installing and managing the parks, it is required to purchase equipments with a standard certificate. Given the children's accidents in public parks duewhile usig such equipments, issues related to the safety of play equipment in the parks should be addressed as fast as possible. Therefore, the present study aimed to investigate the compliance of child play equipments in public parks in Gonabad with safety standards and national standards. Methods: The present study is an applied research conducted by combining descriptive and surveying methods and utilizing experts’ ideas and safety standards related to children's play equipments during fall and winter 2017 in Gonabad public parks where a number of children's playground equipment including slides, swing and flip-flop were installed. In this research, the features of each play equipment that should be recognized as safty features were studied. The first step in the process of implementation was to identify all the information assets in the area under investigation so that effective factors in the field of park equipment safety could be identified completely. At this stage, all national standards for the safety of children's playground equipment in the parks were collected, and all the safety aspects related to the safety of slide, swing, and flipflop were extracted from the standards and a researcher-made checklist was developed to examine these equipments in various fields. Safety evaluations of slides, swing and flip-flop were carried out according to the requirements of Institute of Standards & Industrial Research of Iran, standards no. 6436-2, 6436-3 and 6436-6, respectively. The method of data collection was in field and surveying and after evaluation, all non-conformities were collected through observation and check list and their deviation was determined. Results: Based on the results of the present study on swings, there were 11 cases of noncompliance with the standard requirements of 6436-2. In general, the distance between the hanging points contrasts with the standard requirements. The minimum horizontal distance between the two adjacent seats was not observed. The distance from the surface to the rock was less than the standard. The horizontal distance between the swing seat and the adjacent structure is not in accordance with the standard. The results of the slide evaluation showed that there were 25 cases of non-compliance with standard requirements of 6436-3. In 65% of the slides, the horizontal bar is not provided for open access and in 75% of the horizontal bar height was not standard. In 80% of the slides, the side height of the sliding guard was not 500 mm. In 60% of the slides, their starting section does not have a length of at least 350 mm. In 75% of them, the transition from the head section to the exit section is followed by a sudden gradient change. In 55% of the slides, the minimum length of the exit section is not in accordance with the standard. The results of the flip-flop assessment showed that there were generally 9 cases of noncompliance. In general, the swing ground had no suitable impact-absorption surface and back protection. Very low attenuation causes sudden suspicion. No pedestal was considered appropriate for any of the swabs examined. In all parks, the back of the seat had a curvature and was not rounded. Conclusion: The present study showed that in all surveyed parks, there were various inconsistencies in children's play equipments including slide, swing, flip-flop that did not comply with national standards. Accordingly, it is necessary for city managers to consider national standards in the design of this equipment. In Iran, urban design, has no long history, while designing children's playgrounds, especially for the age group of 5 to 12 years, has had less priority. Much research has been done in European and American societies to improve urban spaces and design a new generation of playgrounds for children. But in Eastern societies, especially in Iran, there is no comprehensive study focusing on children's play spaces, especially for children aged 5 to 12 years. The results of evaluating the swings and slides of urban parks using national standards also indicate that there were various mismatches with relevant national standards in all parks. In all swings of all parks, the distance between the hanging points contrasts with the standard requirements of 6436-2. In some parks, the minimum horizontal distance between the two adjacent swing seats is not met, the swing distance from the ground floor is less than the standard, and the horizontal distance between the swing seat and the adjacent structure is not up to the standard. Also, the results of the slides’ evaluation showed that the horizontal bar was not provided for the open section, the height of the horizontal bar was not between 600 mm and 900 mm above the starting section, the lateral guard height of the sliding start section is not equal to 500 mm, their start section has no minimum length of 350 mm, the transition of the sliding section to the exit section is performed by abrupt change of slope and the minimum exit section length is not as standard. Accordingly, it is recommended to provide the necessary anthropometric data to design and manufacture ergonomically designed equipment for park safety while introducing integrated management of safety, health and environment, to introduce the game park equipment manufacturers in the country. It is also suggested that the relevant organizations and institutions strive to develop anthropometric and dimensional standards and provide the primary data that play an important role in the safe design of the playground equipment by properly interacting with research centers and the Institute of Standards & Industrial Research of Iran. Finally, the results of the present study emphasize the safety audit and enhancement of the safety level of children's play equipment and state the improvement of the safety level of children's play equipment as a necessity. The design of the slides as well as the modification of the playgrounds of children's playgrounds according to relevant standards should be prioritized.

Background and aims: The circadian rhythm is one the most important biological rhythms that regulates the sleep-wake cycle and repeats every 24 hours roughly. This 24-hour cycle includes physiological and behavioral rhythms like sleep cycle. Any disruptions in the body’ s natural rhythms can cause many problems, such as drowsiness, sleep deprivation, reduced physical activity, and mental difunctions. Working at unusual clocks is one of the main factors that can interfere with the circadian rhythm. It is estimated that almost 25% of employees have experienced some kind of shift around the world. Studies have showed that about 62% of these shift workers suffer from sleep disorder, which is defined as a general or partial deprivation of sleep. Various studies have also shown that in the night shift, the performance of individuals is reduced by 5-10%. If the night shifts when accompanied by sleep deprivation on the next day, the performance of people is reduced by up to 30%. There are several work shift schedules in different industries. These include fixed shift, split shift, irregular shift, rotating shift and so on. Rotating shift follows an especial speed and direction. It is necessary to consider one or two days off between the shifts. Employees must at least become eight hours free from work when the shift is changed. In some factories, there is no rest day between the shifts. It makes the workers deprive sleeping for one night. It is well known that lack of rest can effect the human health adversely. Cognitive performance is one of the main functions affected in this situation. Memory, accuracy, and attention as well as reaction time are important cognitive functions which are affected in sleep deprivation. One of the functional differences of the memory system is its differentiation into short-term and long-term memory. Short-term memory is responsible for storing information that is instantly used. Recently, short-term memory has found another definition called work memory. Working memory is actually the new and dynamic of memory, which is actively defined when it is necessary to perform a task. In the most conducted studies, this component of memory has been considered to evaluate the effects of sleep. Many laboratory and field studies have been conducted on the long-term effects of sleep deprivation on cognitive functions but a few studies have been focused on short term effects of sleep deprivation on cognitive functions. Considering the known effects of sleep on physical and cognitive performance of individuals, a study in this field is necessary to make suggestions for modifying such unusual work programs. In Iran, most of workers in main industries are in a shift work. Shifts in these industries are often forward rotating. In many of these industries, people are resting for one or two nights after night shift, which makes the person adapt to this situation. However, some factory has an irregular shift work which expose workers with many problems. Therefore, this study was aimed at investigating the short-term effects of sleep deprivation due to unusual shift works on cognitive function of workers in a painting industry. Methods: This cross sectional was conducted on the total of workers from painting section of an automotive industry. Considering the inclusion and exclusion criteria 80 persons were selected to the study. The mentioned criteria were alcohol consumption, psychiatric disorders and traumatic brain injury, using psychotropic medications and suffer from epilepsy disorder. Moreover, because the educational status of individuals is one of the factors affecting the cognitive function, all who entered the study had diploma. At first, the baseline and demographic data included age, working experience, quantity of sleep during the previous night shift were asked and recorded. Working shifts were rotating forward from morning to night and night to morning. In this factory, after the night shift, the morning shift began immediately without any rest. In order to investigate the effect of this irregular work shift schedule, cognitive performance was measure in two different conditions. Generally, the study was designed in two phases. Firstly, in the first day of the morning shift following the night shift people who did not take any rest in previous night were entered into the first phase of the study. Thus after giving a questionnaire contained some question about quality and quantity of sleep, people with the sleep duration less than two hours were selected for the rest of the study. Cognitive performance was evaluated in three different domains including working memory, selective attention and reaction time by the computerized tests. For assessing the working memory, a validated Persian test of N-Back was applied. STROOP test and Simple Reaction Time Test (SRTT) were also used to measure attention and reaction time status, respectively. In N-Back test, subjects have to react to all of the stimuli so it requires constant control and updating of the information in the working memory and has a very strong reputation for evaluating the working memory. This test has three different levels of complexity. In this study, its first level, N1, was used because studies show that its first level is more sensitive to the effects of sleep deprivation. In this test, 120 stimulants appeared on the screen in 5 minutes. At the first level, the subject had to compare each number with the preceding number and press a certain key on the keyboard. The Persian version of the Stroop computerized test was also used to evaluate the selective attention of individuals. The Stroop color test enables the individual to process related data, thoughts or actions while rejecting unrelated or inaccurate information. In this experiment, four colored circles below the color words are displayed. The person must press the color key word that may not match the color of the circle, regardless of the color displayed on the keyboard. Finally, the error rate and response time are reported as variables in this test. In SRTT, green circles appeared randomly on the screen, which the person had to press a key on the keyboard in the shortest time possible after it appeared. The reaction time was recorded in milliseconds. All tests were carried out in a quiet place where there was no noise, within beginning of morning shift until noon. One week later, the second phase of the study was performed in the afternoon shift when workers got adequate rest in the previous night. It should be noted that in this stage, people were also asked about duration of sleep in the previous night and those who had any sleep deprivation for any reason were temporarily set aside and, at an appropriate time, repeated the tests. The SPSS version 22 was used to stablish the statistical analysis. The tests used included one-way ANOVA, paired t-test and Pearson correlation analysis. Results: The results of one-way ANOVA showed that there was no significant difference between age and work experience (p>0. 05). The amounts of sleep duration of people with adequate rest and without any rest were 7. 5± 2. 5 and 3. 5± 1 hour, respectively. The mean and standard deviation (SD) of the working memory (N-Back) in both situations, when workers had adequate rest and without any rest were 100. 12± 5. 79 and 85. 23± 23. 13, respectively. The average of obtained scores for selective attention for both situations was 2. 51± 1. 3 and 8. 27± 4. 4, respectively. Mean and SD of the reaction time test were also 500. 21± 89 and 445. 54± 105, respectively. Paired t-test analysis revealed that obtained scores for working memory and selective attention, when workers were in the morning shift and had sleep deprivation, were weaker than the time that they had enough sleep in the previous night (p<0. 05). Additionally, the level of error in the test was higher in these subjects. The reaction time was also longer in people who with adequate rest time, although there was not a significant difference between two groups. Pearson's analysis also revealed a strong correlation between the sleeping hours and memory scores, as well as a fairly good correlation between sleep hours and the number of errors in the attention variable (r2 =-0. 44). Conclusion: People working in the painting sections of the major automotive industry need to be in an acceptable cognitive performance due to the nature of their work. In general, unusual shift works and sleep deprivation reduce cognitive function in the memory and selective attention scopes because of inadequate rest time between shifts. It has been shown that brains forehead which is responsible for executive functions, shows a significant decrease in metabolic energy consumption in sleep deprivation. Since working memory and attention are both related to this part of the brain, therefore, they are vulnerable to sleep deprivation and change. The results of this study also showed that work in the night shift can make people fatigue, which reduces the executive and cognitive performance of individuals. Therefore, it seems to be necessary adjusting the work schedule in order to considering adequate time to rest between two shifts in unusual work systems.

Background and aims: There is always an interaction between man and his environment that can be the cause of physical, physiological and psychological stress on people and also cause discomfort, annoyance, and have direct and indirect effects on their performance and productivity, health and safety. People in their workplace are exposed to many factors related to work activities and environmental factors, which can affect their health. Thus, workplace disruptions such as noisy environments can cause safety problems, reduce employee’ s morale and has undesirable effects on their performance, working memory, and attention. For these reasons, ergonomic designers must be capable of designing the physical environment because the design of the environment not only keeps people's performance high, but also provides a safe and healthy environment for improving employees' health. Noise can also negatively affect communication between people. Different sources of noise production can affect employees and negatively affect their comfortable, functional and communication aspects. Noise also effects mental activities and can cause employees to become tired early and increase their computational errors. Because of high workload and the banks' competition to attract customers in order to provide better services, quiet workplace environments are essential for staff comfort and optimum performance; so right designing workplace can have a high impact on people's comfort and productivity. Speech Interference Level (SIL) is a simple way to predict or evaluate speech intelligibility where the conversation occurs directly in a noisy environment. At open plan offices, employee and customer communicate face-to-face and information exchange is done in that way. In recent years, many banks in our country have established their own workstations as sited customers and face-to-face with bank tellers, but so far no study has been conducted on the changed employees' workstations and its effect on speech interference. A question is whether the workstation redesign increase the Speech Interference Level and improve Intelligibility ratings for speech communications? Therefore, the purpose of this study was to study the effect of redesigned workstations on SIL among bank tellers. Methods: This is a descriptive-analytic and interventional study carried out for one year in three branches of one of the governmental banks of Hamadan province (N= 12). Twelve workstations were redesigned and installed after measuring the sound and calculating Speech Interference Level, and calculating the distance between customer and employee. Bank tellers are those who have a direct relationship with customers and perform banking tasks. They had to sit long during the day and they spent all their time working on computers and they were getting things done and receiving customer financial requests. They used the workstations were constructed in the present study. The tools for data collection in this study were: 1) demographic and occupational questionnaire, 2) sound measuring and frequency analyzer CEL-450، 3) A questionnaire with a question “ What noise sources in your workplace do you annoy? ” to determine annoying sound sources and 4) ISO 9921-2003 standard to determine speech interference level of the noise at the listener's ear (LSIL), Speech level, Speech Interference Level (SIL) and Intelligibility ratings for speech communications. SIL is a simple way to predict or evaluate speech intelligibility, Speech intelligibility also increases with increasing SIL. speech intelligibility is divided into 5 rating (bad, poor, fair, good and excellent) based on SIL, also in sensitive situations where short messages are sent include important numbers, ability to understand at least "good" is recommended by increasing speech effort; the communication will be “ fair” if the difference between LSIL and the speech level (LS, A, L) that both determined at the listener’ s position is greater than 10. Measuring the sound within 1 meter of the speaker's mouth, according to ISO 9921 (2003) for normal sound (60 dB) was considered. It was measured for 15 minutes at 10 a. m. to 13 p. m. every shift that they had the highest number of customers, and measuring was done twice for each workstation (total 24 times). To calculate LSIL, the sound pressure level was measured in four octave bands with the central frequencies 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz at the listener position and during the normal communication period in time-weighting “ slow” . The sound pressure level was measured for 15 minutes and the average of these pressure levels was calculated. After collecting the preliminary data, bank teller workstations were redesigned and built. Some actions were taken to reduce speech interference and improve communication between bank tellers and customers; For example, insert a glass between customer and bank teller and create 12 vents (diameter =2 cm) at a customer's mouth height to improve communication, changing the workstation so that the operator and customer interact face-to-face and insert chair for customers to sit in, reduce customer gathering in front of the workstations, reducing the distance between the customers and the bank tellers by creating an arc at the table, Enhancing employee privacy by placing the glass between employees in beside workstations, increasing the glass height between the bank teller and the customer to prevent customer standing communicate with the bank teller. The mean distance between bank teller and customer prior to redesigning the workstations was 123 cm which was reduced to 103 cm in redesign; the mean distance between two employees was 95 cm, which increased to 115 cm after the redesign. Environmental interventions also include the installation of perforated acoustic tiles made of plaster as a false ceiling, so that, by installing them the distance between the main and false ceilings was 25 cm and there was an empty space between them which absorbs more sound. The walls of the branches were also covered with wall plugs that made of PVC and MDF, and the floor was improved. Data were collected before and after the interventions and they were compared. Data analysis was performed using SPSS software, version 16. Data were analyzed using descriptive statistics (mean and standard deviation) and analytical statistics. The Paired t-test was used to compare the mean results of the LSIL and SIL. Results: In the present study, all the bank tellers were male. Everyone was married, their mean age was 38. 25 (5. 62) and work experience was 15. 25 (6. 87) years. Each bank teller was doing 30-50 customers' finances task in one shift. All participants stated that their rest time was less than 30 minutes in a shift and they are working 7-8 hours in a sitting position; none of the participants had a history of hearing loss or other hearing problems. Results from annoying sources of noise showed that the most annoying sources of noise in all three branches were the noise of customers (42. 85%) and the sound of money counting machine (33. 3%); Printer noise was the lowest (4. 76%). Before the interventions, mean speech interference level (LSIL) was 59. 50 dB (4. 07) that was then reduced to 54. 98 (5. 52) dB and this decrease was statistically significant (p <0. 05), also the results of evaluation and comparison of SIL in the workstations after and before the interventions showed that SIL increased and it was statistically significant (P <0. 05), the mean of SIL before interventions was-1/00 (3. 98) which reached to 5/09 (5/23) after interventions, Lots of noise in the workplace reduces SIL which in turn reduces the speech intelligibility between the bank tellers and the customers. Therefore, the interventions have improved the speech intelligibility in all three branches. So that after interventions, the "fair" speech intelligibility increased from zero to 4 cases (16. 7%); and it is expected that by improving speech intelligibility, peoples' efficiency and concentration will increase; so it can be said that high levels of workplace noise reduce SIL, which in turn reduces the speech intelligibility between bank tellers and customers. 22 of the 24 measurements before the new workstations were in the “ bad” speech intelligibility range, which was reduced to eight after the new workstations were installed, but after the interventions, speech intelligibility in most workstations (50%) were “ poor” ; Upgrading the speech intelligibility from bad to poor can be a sign of improvement; but further studies are needed to survey the sources that impair intelligibility in order to reach good or excellent level and reduce problems due to poor intelligibility such as longer speaker and listener speech and computational errors. Conclusion: The overall purpose of this study was to examine the effect of redesigned on Speech Interference Level (SIL). The findings of this study showed that the interventions were effective on SIL. According to the results of this study, redesigning work stations and environmental interventions in open plan offices can influence SIL and improve the speech intelligibility, that it can prevent errors and increase concentration and reduce fatigue by peoples' privacy and controlling annoying sound sources. Finally, it can be said that the workstation redesign and layout can improve the acoustic working environment.

Background and aims: The construction industry, sites, and projects are the most dangerous industries in terms of the risk of occupational accidents and injuries. Important factors that have led the industry as a health, safety, environment (HSE) high-risk industry in the world can be cited such as continuous changes in construction projects, using a lot of resources, poor working conditions, non-continuous employment, cross-seasonal work, and harsh environment. Risk of a variety of occupational accidents (e. g., fall, throwing objects, slipping, collision and crash, chemicals, electrical shock, abrasion, and manual material handling, etc. ), inherently exist in all construction projects. Given the existence of such risks, construction sites often fail to achieve their goals, such as the completion of the project, the estimated budget, project quality and expected extent of accidents and damages. Modeling and analysis of the indicators of the construction HSE risk management system to reduce the incidents and consequences of accidents, as well as its relationship with accidents, can be a very good self-monitoring approach. Occupational safety and health challenges are tied largely to the construction industry. In developed countries, the rate of occupational accidents in the construction industry is 17%. This rate is 45% in Iran which is 2. 6 times the global rate. Although construction workers make up less than 12% of Iran’ s workforce, the rate of injuries caused by accidents in this industry is high. Identifying the factors affecting occupational injuries is a retrospective approach to analyze, prevent and reduce these injuries. One of the most effective accident analysis techniques developed to understand and explain the causes of events and analyze the path leading to accidents and their consequences is Root Cause Analysis (RCA). Accordingly, the purpose of this study is to analyze the path of causes resulting in occupational injuries involved in construction work by using structural equation modeling. Methods: This study was a cross-sectional retrospective analysis of occupational injuries that occurred in 82 small and medium-sized construction projects during the 11 years (2007-2017). The statistical population included all occupational injuries that occurred in construction projects. The main variables in this study were different types of injuries caused by occupational accidents. The initial size of the statistical population was 1328 accidents. Therefore, 1232 accidents were selected as the study sample based on the inclusion and exclusion criteria. It should be noted that the minimum sample size for analysis of a structural model should not be less than 200. The main tool for collecting data in this study was a checklist for reporting occupational accidents in construction projects. Interviews and records were also used to complete the data. The implementation of the study included "five steps". Step 1: Of 1328 accidents, based on the inclusion/exclusion criteria, 1232 accidents leading to injuries were selected. Step 2: Occupational injuries were analyzed based on Root Cause Analysis (RCA). Step 3: Different dimensions of various factors affecting occupational injuries in the construction projects were identified, evaluated and classified. Step 4: A conceptual model for analyzing the causes of construction injuries was drawn following the chain of events and path analysis. Step 5: Finally, the associations, interactions, and effects of all factors and variables were analyzed using the structural equation modeling. Applying IBM SPSS AMOS version 0. 22, the structural equation modeling was used for data analysis. Results: Generally, occupational injuries were reversely related to individual factors, organizational factors, safety training, and risk management, whereas they are positively related to unsafe conditions and actions and the type of accident. Approximately, two-thirds of the accidents had occurred during construction activities and more than 70% of the accidents occurred for small contractors. The desirability degrees of two key safety program parameters i. e. duration and content of the programs (quantity and quality) were estimated to be 23. 5% and 12. 0%, respectively. The highest degree of the desirability of risk management variables belonged to safety checklist (28. 7%) and usage of personal protective equipment (PPE) (22. 1%). Workplace hazards (63. 6%) and dangerous work methods (56. 1%) caused the highest share of accidents. The majority of unsafe actions were linked to inadequate knowledge and awareness (65. 5%) and non-usage of Personal Protective Equipment (PPE) (57. 9%). The most common accidents fell from height (31. 2%) and falling objects (27%). The analysis of occupational injuries showed that 1. 5% of the accidents had resulted in death and 10. 4% had led to physical limb deformation. Path analysis of construction injuries based on SEM revealed that occupational injuries had a significant inverse relationship with individual and organizational factors, safety education and risk management (p<0. 05). The values of the goodness of fit, χ 2/df, RMSEA, CFI, and NNFI (TLI) were calculated to be 2. 79, 0. 059, 0. 894, and 912 /, respectively. Therefore, based on these results and comparing them with the desired criteria, this model seemed acceptable. Conclusion: Modeling based on path analysis can support the multiple causation theory of occupational accidents. Different causative factors and related indicative variables including individual and organizational factors, safety education, risk management, unsafe conditions, and unsafe acts and the type of accident as a set of causes, have been involved in the chain and process leading to injuries caused by construction accidents. Regarding the type of accident, fall from height is considered as the most important indicative variable, so this variable is important for construction injury analysis. Imperfect and weak risk management and organizational factors can contribute to the creation of these unsafe conditions. Also, unsafe acts can be influenced by other variables and factors such as individual and demographic factors and safety education. Inadequate and inefficient education can lead to imprecision, dangerous behaviors and various types of human error and affect the type and degree of injuries in construction activities. Occupational injuries had significant correlations with hazard identification in construction, various types of risk assessment, accident analysis and effective event reporting, as well as implementing a variety of control measures such as personal protective equipment, practicing and supervising discipline on the construction site and holding safety-related meetings on the construction site. Considering that environmental construction projects are always accompanied by high risks, a systematic and efficient approach to identify, assess, control and reduce risks can be useful for optimal safety system performance and reduction of construction injuries. Up to current study promoting safety in the construction sector requires a comprehensive planning. This planning should be based on an intelligent model using all variables and factors affecting occupational injuries. This study showed that inter and intra-factor relationships are always effective in occupational injuries in the construction or any other industrial environment.

Background and aims: Occupational health engineering is one of the important fields of medical sciences. In this field, the apprenticeship course is considered an essential part of its bachelor level and bachelor students require acquiring special skills to perform their professional tasks to meet the needs and expectations of faculty members as well as employer and worker expectations. The apprenticeship course is suitable for trail and test under the supervision of academic educators and industry experts. The essential part of the practical skills training occurs during this period. In general, the apprenticeship course leads to acquiring valuable practical experiences and improving behavior and attitudes of students. It also prepares them to acquire future work skills. Apprenticeship, like other courses, requires evaluation based on a standard and effective tool that can accurately measure the educational and expected goals. By using this valid tool, the success of interventional programs can be evaluated with more assurance to improve the efficiency of the apprenticeship period. Thus, the development of a standard evaluation is crucial. This study aimed to develop and validate a tool for assessing the apprenticeship course in the field of occupational health and safety engineering in Iran. Methods: This study was conducted in the occupational health and safety engineering department of Shahroud University of Medical Sciences during the second semester of 2016-2017 to the second semester of 2017-2018. Students of these two courses were evaluated using the designed evaluation tool. The dimensions of the tool were developed based on curriculum of apprenticeship course in the field of occupational health and safety engineering, literature review and panel discussions with the participation of occupational health professors and experts. On this basis, three dimensions of 1. Educational and learning objectives, 2. Management and personal skills (behavioral objectives), and 3. Development of professional job and entrepreneurship competences and qualifications (management objectives) were defined. Then, some comprehensive criteria in accordance with these three dimensions were prepared. These criteria were determined based on the review of relevant literature, interviews with professors and educators in the field of occupational health and safety engineering. These criteria were used as a conceptual framework for designing the items. Then, in accordance to the conceptual framework and considering the frequency of criteria for each area, appropriate items were developed for all of them. The conceptual fit of each item with its measured dimension was maintained in the process of developing items for all of the dimensions. Five-point Likert scale (very poor (1), poor (2), moderate (3), good (4) and excellent (5) was used to score the items. An excellent score was considered for very appropriate performance and without any need for guidance, a good score was considered for often satisfactory performance with minimum guidance, a moderate score was considered for inappropriate performance requiring guidance, a poor score was considered for inappropriate performance requiring guidance and supervision, and a very poor score was considered for extremely inappropriate performance requiring precise and thorough supervision and guidance. Validity was assessed by Face validity, content validity ratio (CVR), content validity index (CVI) and Item Impact score (IS). Reliability was evaluated through internal consistency (Cronbach’ s alpha coefficient) and test-retest reliability analyses. Results: Based on the three dimensions defined, in the first step, a questionnaire with 44 items was designed. Each of dimensions of educational and learning objectives, management and personal skills, and the development of professional job and entrepreneurship competencies had 14, 20 and 10 items, respectively. The IS of the item showed that all designed items had a score of above 1. 5. Thus, in this step, none of the items were eliminated and all of them were considered important and appropriate from the target’ s point of view. Based on the results of CVI and CVR, three items were deleted. Total mean scores of CVI and CVR was 0. 85 and 0. 76, respectively. These scores, indicating the good content validity of tool from the experts’ point of view. The Cronbach’ s alpha, intraclass correlation coefficients (ICC), and test-retest Pearson correlation coefficients for the final version of the tool were 0. 835, 0. 899 (p<0. 001) and 0. 913 (p<0. 001), respectively. Based on the results of reliability, one item was deleted. Conclusion: In general, the positive results of validity and reliability showed the desirable psychometric property of the 40-item questionnaire of evaluation of the apprenticeship course in the field of occupational health and safety engineering with three dimensions of educational and learning objectives, management and personal skills, and the development of professional job and entrepreneurship competencies. This standard tool, in addition to evaluating the level of apprentices’ information and knowledge, can be a desirable tool for evaluating the expected job skills and competencies required in the field of occupational health and safety engineering. This was a preliminary study and the authors of this research faced with various limitations. Thus, further studies are needed for more comprehensive application of the designed tool as well as reassessment of the psychometric properties and eliminating its defects and disadvantages in other occupational health and safety engineering departments in Iran. Totally, The results indicated that the developed tool had good psychometric properties and can be used as a standard measure for assessing the apprenticeship course for occupational health and safety engineering students.

Background and aims: Outdoor workers are vulnerable to heat stress and climate change due to their occupational and environmental conditions. Short-term exposure to extreme heat (acute exposure) can lead to rise the core body temperature, which it may directly cause heat related illnesses such as mild rash, cramps, heat exhaustion and heat stroke. It is reported that long-term chronic exposure to heat leads to chronic kidney diseases, cardiovascular diseases, and mental health problems. The vulnerability consists of three components including sensitivity, exposure, and adaptability. According to the third assessment report of the intergovernmental panel on climate change (IPCC), the defiition of vulnerability is the degree to which a system or an individual is sensitive to, or unable to adapt to the adverse effects of Heat Stress and Climate Changes. Sensitivity is the physical capacity of workers to be affected by a hazardous agent like the heat. Sensitive is an intrinsic and internal factor that indicates how the person is vulnerable to heat stress. Individual risk factors in heat stress may decrease the individual’ s tolerance to heat stress. The ability of system to cope with climate changes and adapt to extreme heat to reduce the risks and consequences resulted from these conditions is called adaptive capacity. Adaptation leads to reducing the vulnerability and increasing heat tolerance. Adaptive capacity is definedas “ Theabilityof asystemtoadjusttoclimatechange, to moderate potential damages, to take advantage of opportunities, or to cope with the consequences” . Therefore, it should be necessary to reduce the level of vulnerability through providing the control programs and strategies. Since there are no national laws, regulations, guidelines to protect outdoor workers against heat stress in the country, only the relevant policy in this area is the permissible occupational exposure limit. Therefore, the present study aimed to develop a comprehensive operational program to reduce the vulnerability of outdoor workers to heat stress and climate change. The results of this study can be very effective in decision making of the macro-management as well as planning of control measures in the country. Also, the program presented in this study can be helpful for organizations in charge of health and safety such as the Ministry of Health and Medical Education and the Ministry of Cooperatives, Labor and Social Welfare (which are responsible for maintaining, protecting and promoting the health of the workforce). Methods: According to the objective of the study, which was the development and implementation of an operational plan to reduce the vulnerability of outdoor workers to stress and climate change, several technical panels and brainstorming sessions were held with the cooperation of the Institute for Environmental Research, Tehran University of Medical Sciences by eminent experts in the fields of industrial hygiene, environment engaging in Medical Sciences University, Department of Environment and Ministry of Health and Medical Education during the 2014-2016. The main components of the vulnerability, the areas and strategies for application of an operational program to reduce the effects of exposure to heat stress and climate changes in outdoor workplaces were taking into account in the meetings. Also, the Delphi technique (due to the lack of access to some of the professors and executives’ directors), the study of text books and articles have also been used in this study. Delphi, as an effective and highly flexible technique, is used to achieve consensus or forecast future events. It is a proper method to collect the opinions of experts, who cannot easily meet each other due to geographical distance. Using Delphi as a research method is useful when there is no integrated knowledge about a specific issueorproblem. Results: According our finding, six main components including general plans and policies (16 Strategies), prevention programs (6 Strategies), conservation programs (11 Strategies), training programs (11 Strategies), management planning (14 Strategies) and research and future study programs (11 Strategies) were proposed in the form of 69 strategies with three goals: reduction of sensitivity, reduction of exposure levels and increase of compatibility. Conclusion: The proposed program and strategies in present study can be used to prepare guidelines for work in hot environments. Our results can be of great help to the occupational health and safety-related organizations such as the Iran's Ministry of Health and Medical Education and Ministry of Cooperatives, Labour, and Social Welfare for planning and providing preventive procedures and control measures, in order to take effective action to maintain and improve employees' workplace health. Should be noted that the development and implementation of the mentioned policy require the cooperation of all members including employers, health and safety committee, supervisors and employees.

Background and aims: Musculoskeletal Disorders (MSDs) are widespread around the world and are the second most common cause of disability in work settings. A number of occupational factors such as forceful exertions, awkward postures, repetitive movements, and local contact stress can lead to the development of musculoskeletal problems. There is an association between the use of hand tools and onset of work-related musculoskeletal symptoms. Working with hand tools exposes users to one or more of these factors. Using hand tools, particularly if the job requires using the tools for a prolonged period of time, may also cause increased discomfort and fatigue which may be due to the existence of high stresses on the anatomical structures of the hand. Carpal Tunnel Syndrome (CTS) and writer’ s cramp are common injuries among writers, which may occur through excessive precise activity with the exertion of hands and fingers during writing, particularly with inappropriate techniques. There is strong evidence of a positive association between exposure to a combination of ergonomic risk factors (e. g., force and repetition, force and posture) and CTS. Writer’ s cramp appears to be triggered by writing for long period of time. Ergonomic hand tool design involves optimizing the handle to effectively carry out the intended function of the tool with the least load to muscles, tendons, skin and joints. One aspect of this process is to optimize hand– tool contact area in order to maximize grip strength, minimize contact stress with special interest to sensitive areas of the palm and wrist, and provide appropriate tactile feedback. The grip strength is determined by the biomechanical advantage created by finger joint angles as well as the physiological advantage associated with the differences in muscle length. The hand posture and the related grip strength are influenced by the shape of the handle and the hand size. Anthropometric measurement of human limbs plays an important role in design of workplace, clothes, hand tools and many products for human use. To design any product for human use, human factors engineers/ergonomists have to rely on anthropometric data, otherwise the output product may turn out to be non-ergonomically designed product or the product may turn out to be ergonomically incompatible. The interaction of handle size and shape with the kinematics and anthropometry of the hand have a great effect on hand posture and grip strength. The process of designing and selecting the hand tools to provide a better fit for the user lies on the shoulders of human factor engineers /ergonomists. Poor ergonomic hand tool design is a well-known factor contributing to biomechanical stresses and increasing the risk of cumulative trauma and carpal tunnel syndrome disorders of workers. Hand anthropometry is useful for determining various aspects of industrial machineries, so as to design the equipment and machines for higher efficiency and more human comfort. Handwriting is an important skill for school-aged children and there is clear relationship between pencil grip posture and handwriting skills. Ergonomic factors like pencil grip, paper position, sitting posture for writing, upper extremity stability and mobility, should be considered with the purpose of effectively promoting efficient handwriting skills. Ergonomically designed hand tools can reduce user discomfort, biomechanical stresses, and risk factors for musculoskeletal symptoms and injuries in hands. Furthermore, by improving the quality and usability of hand tools, it is possible to improve efficiency and work productivity. Using an ergonomic pen is an effective solution to reduce upper limbs musculoskeletal disorders. Using a pen with ergonomic design, especially from childhood, can cause to create a right grip posture for writing and improves the pen grip posture among older people. By getting upper limbs at neutral posture, writing is more comfortable lower chance of hand injuries. Given the above, the aims of this study were to design, fabricate and evaluate a new type of pen to improve the posture of the wrists, hands, and fingers, and enhance writers’ comfort. Methods: This interventional study was carried out in the Department of Ergonomics, Shiraz University of Medical Sciences from October 2013 to May 2014. The study consisted of 3 phases, including: a) Designing an ergonomic pen: by reviewing the literature and evaluating the features of the available pens, the idea of the design of a new pen was formed. The features, such as optimal grip, attractive and desirable form, reducing contact stress and muscles fatigue, as well as adapting to hand size for everybody, were focused in the design process. b) Fabricating the model and the prototype of the pen based on anthropometric data: the anthropometric parameters of hand that were considered in the design of the pen included: the length of the thumb, the index finger, the middle finger, and hand thickness. The models of the pen were made by plaster. After modifying the details and layout of the pens, one size of the models was made from the final material. It should be mentioned that the prototype was designed and made just for right-handed people. c) Assessment of some parameters of the new ergonomic pen: In the next step, the ultimate prototype with its final materials was assessed. A new pen made by a 3-dimensional printer and three common pens were compared by 28 subjects. The participants had no musculoskeletal symptoms in the upper limp. The data collection tools consisted of visual analog scales (VAS) and Borg’ s rating physical effort scale. After the users performed the writing tasks by four pens, they were asked to rate comfort using the VAS. VAS is a 10-cm instrument, with values from zero representing extremely uncomfortable and to 10 indicating extremely comfortable. The physical exertion/stress felt by each user during the writing task was evaluated using Borg scale of 6-20. In this scale, the values near 20 and 6 represented more difficulty and more comfort, respectively. This scale has been used in a number of studies. Data were statistically analyzed by one-way ANOVA and independent t-test using SPSS software version 21. Results: The means (SD) of age and duration of working with pen per day (Hrs) in the subjects studied were 22. 17 (3. 41) and 5. 83 (1. 22), respectively. In accordance with the basic idea, the pen was designed in five sizes for percentiles of 5th, 25th, 50th, 75th, and 99th to cover at least 90% of the target group. The prototype was one size of the pen models that was printed by 3D printer. The highest mean (SD) of the users’ comfort was 8. 35 (0. 95) related to the newly designed pen. The results revealed a reduction in the users’ rating of perceived exertion while writing with the new pen. Conclusion: In this study, a new type of pen was designed and fabricated to improve upper limb and hand postures while writing. According to findings of this study, the new pen helped correct the grip of hand while writing. The results of this study showed that the ergonomically designed pen was more comfortable to use. Also, it exerted less physical stress on tissues of hand compared to the other evaluated pens during writing. The new ergonomic pen with specific features (i. e., different form, and design in various sizes to provide more adaptation with hand) increased the users’ comfort and reduced the users’ physical exertion while writing. It is believed that using the new ergonomic pen can prevent and reduce wrist and hand musculoskeletal injuries such as carpal tunnel syndrome and cramp in the long periods of time.