دو ماهنامه سلامت کار ایران
سال شانزدهم شماره 3 (امرداد و شهرویور 1398)

Sickness absence is a major socio-economic problem imposing a huge amount of cost to societies.This issue has been widely concerned over the last few years. Absence from work entails complex conditions and multifactorial etiology. According to previous studies, 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 addition, previous studies indicated that the likelihood of returning to work decreases with longer absence from work.  In this light, it is essential to identify the workers at risk of sickness absence, particularly long-term sickness absence.
The ability to stay at work and handling the work demands have been discussed as work ability, which is actually a balance between worker’s resources and work requirements.
The work ability index (WAI) provides a valuable tool to assess the work ability. It can serve research purposes and clinical assessments in occupational health, aimed at evaluating the ability to work during occupational health examinations and environmental monitoring. Furthermore, the WAI helps better identify the workers at risk of long term sickness absence and early work loss.
Various studies have reported that lower WAI scores are correlated with increased incidence of sickness absence and lengthened duration of sickness absence. In a study on construction workers in the Netherlands, Alavinia et al. found that workers with moderate and good work ability are at higher risk of sickness absence than workers with excellent work ability. Moreover, it was revealed that WAI can be a good predictor for sickness absence, especially for prolonged periods of absence from work.
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.

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. In terms of BMI, they were divided into two categories of less than 25 and equal or greater than 25. Moreover, the education levels included three categories of low, medium, high. 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 ranging from 0 to 10 points, 2) work ability in relation to the demands of the job ranging from 2 to 10, 3) number of current diseases diagnosed by physician ranging from 1 to 7, 4) estimated work impairment due to diseases ranging from 1 to 6, 5) sick leave during the past year (12 months) ranging from 1 to 5, 6) Work ability in the forthcoming two years covering 1, 4 and 7, and 7) mental resources ranging from 4 and 7. In all items,the highest scores of WAI represent  the best work ability. The overall score of WAI obtained by the total points achieved in the seven items ranged from 7 to 49, where higher score indicates a greater work ability.
 The WAI scores in workers with short-term and long-term sickness absence from work and the combined sickness absence were compared against those in workers without any sickness absence. In this study, the dependent variable was WAI , while the independent variables included sickness absence and occupational and demographic characteristics. 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 to be 0.05 with confidence interval of 95%. The statistical analysis involved SPSS 16.

Of the 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% were 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 value=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 value=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 value=0.002) and (OR=2.256 and P value<0.001), respectively. Short-term Sickness absence was higher among shift workers (OR=1.84 and P value=0.011). Moreover, the long-term absence was more frequent among smokers while short-term absence was more frequent among non-smokers (OR=2.12 and P-value=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 value<0.001). The mean score was 42.5±4.3 in subjects with a BMI less than 25 and 41.9±4.3 in subjects with BMI≥25 (P value=0.049). The WAI scores in the population indicated no significant differences in terms of age, work experience, education, shift work and work group. 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 value<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-value<0.001 and 0.019, respectively). Furthermore, there was a significant relationship between the work group and absence/non-absence as well as between smoking and short/long-term absence (P value=0.029, <0.001 respectively). This was consistent with results of previous tests for comparison of mean values (t-test and chi-square). 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 value=0.013). Moreover, it was greater in the short-term absence subjects than the long-term absence subjects (P value=0.045).
“Work impairment due to disease” was greater in the non-absence group than the absence group (P value<0.001). Moreover, it was greater in the short-term absence group than the long-term absence group (P value<0.001). 
“Psychological resources” was greater in the non-absence group than the absence group (P value=0.033). However, there was no significant difference in comparing the two groups with short and long-term absences.
In this study, the subjects were divided in terms of work ability index into two categories of low work ability (including those with low and medium WAI) and high work ability (including those with good and excellent WAI). 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 value<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 value<0.001).

This study intended to assess the relationship between WAI scores, sickness absence and the role of individual and occupational factors among the workers involved in the Iranian automotive industry. The mean WAI score was 42.19, and 40.7% of subjects were categorized as excellent, 49.5% as good, 9.3% as moderate and 0.5% as poor.  In this population, there was a significant relationship found between WAI and sickness absence. This 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.
According to the results of this study, the lower WAI scores increased the episodes and lengths of sickness absence. The findings suggested that WAI can be correlated with short-term and long-term Sickness absence and can be employed as a simple and useful tool to identify workers at risk of sickness absence.

Parks are a place for children's play and activity, so making safety these environments that are somehow a social work environment is one of the requirements of environmental planning. Making safety these environments is one of the requirements of environmental planning. It will be necessary to provide quality and sustainable conditions for park playgrounds to improve the safety and health of children. This will also initially require proper physical conditions and the development of safety-based play equipment. Improving safety and improving the quality of equipment requires compliance with standards. Currently, no organization has the task of periodically reviewing the safety of children's play equipment. In general, the process of building and installing children's play equipment in public parks in cities is such that the standards for equipment’s are formulated and published by the Institute of Standards & Industrial Research of Iran and the manufacturers of this equipment are notified and manufacturers are required to design children's play equipment according to the most up-to-date standards. A standard certificate will be issued for this equipment after the manufacturer has complied with the requirements.
 Since the municipality is responsible for purchasing, installing and managing the parks, the municipality is required to purchase equipment that has a standard certificate. But because some of the children's play equipment was purchased at the time that there was no standard for that equipment, some of this equipment does not have any standard certification. In addition, some equipment is standard certified at the time of purchase, but is not valid at the present time. Given the importance of the cases mentioned and the subject of children's accidents, many economic and social issues are involved. Health promotion plans for this sensitive group and issues related to the safety of play equipment in the parks are among the important issues that should be addressed before accidents and adverse effects in children. Investigating and evaluating the safety status of the parks can improve the health and quality of life of the visitors and make them comfortable in utilizing the facilities of the parks. Therefore, the present study aimed to investigate the compliance of child play equipment in public parks in Gonabad with safety standards and national standards.

The present study is an applied study that was conducted by combining descriptive and surveying methods and utilizing experts and safety standards related to children's play equipment during fall and winter 2017 in Gonabad public parks. The study area was the public parks of Gonabad, where a number of children's playground equipment including slides, swing and Flip-flop were studied. In this research, the first and foremost question that has caught the researchers' minds is that "What features of each child's play equipment should be included to be recognized as safe?” and following this initial question, the research structure was formed. 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, Flip-flop (on the playgrounds in the parks) were extracted from the standards and a researcher-made checklist was developed that examines the standards for these equipment in various fields. Safety evaluation of slides, swing and Flip-flop were carried out according to the requirements of Institute of Standards & Industrial Research of Iran standards 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.

Based on the results of the present study on   Swings, there were 11 cases of non-compliance 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 is not observed. The distance from the surface to the rock is 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 is not standard. In 80% of the slides, the side height of the sliding guard is 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 non-compliance requirements. In general, the swing ground does not have a good 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 has a curvature and is not rounded.

The present study showed that in all surveyed parks, there were various inconsistencies in children's play equipment (including Slide, Swing, Flip-flop) that did not comply with national standards. Accordingly, it is necessary for city managers, including small town managers, to consider national standards in the design of this equipment. In our country, urban design, in today's sense, does not have a long history, while designing children's playgrounds, especially for the age group of 5 to 12 years, has had less priority. So far, much research has been done in European and American societies to improve urban spaces and design a new generation of playgrounds for children to attend and various solutions have been proposed. But in Eastern societies, especially in our country, there has not been a comprehensive study focusing on children's play spaces, especially for children aged 5 to 12 years. And sometimes actions are taken with the delay of time and behind the experience of Western societies in the form of modernization and improvement plans. The results of evaluating the swings and slides of urban parks with national standards also indicate that there are 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 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 does not have a 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 is prioritized.

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 functions. 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 10-5%. 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. The speed means the number of times working a particular shift before moving or rotating to a different one. Working in every morning, evening, and night shifts for two consecutive days. It is necessary to consider one or two days off between the shifts. Employees must at least 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 on 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. Memory is defined as the ability to record, remind, memorize, and retrieve information. 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.

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 didn’t 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.

The results of one-way ANOVA showed that there was no significant difference between age and work experience (p-value> 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-value< 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).

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.

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; So workplace disruptions such as noisy environments can cause safety problems, reduce employee morale and undesirable effects on 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 keep people's performance high, but also provide a safe and healthy environment for improving employees' health. Noise can also negatively affect communication between people. Banks are open plan offices and the financial services provided by bank staff that requires employee's mental activity. Different sources of noise production can affect employees and negatively affect their comfortable, functional and communication aspects. Noise also effects on mental activities can cause employees to become tired early and increase their computational errors. In a bank environment where conversations between bank tellers and customers are necessary to conduct banking tasks, interfering with ambient noise, causing annoyance, human error, and ultimately failed to provide banking services. 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 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 now arises, is workstation redesign increase the Speech Interference Level and improve Intelligibility ratings for speech communications? Therefore, the purpose of this study was redesigned workstations and make environmental changes and its effect on SIL among bank tellers.

  This study is a descriptive-analytic and Interventional study, this was 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.

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 were 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.

The overall purpose of this study was redesigned workstations and environmental interventions in the open plan office and their effects 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.

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, and cross-seasonal work, 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. In general, some studies have shown that the use of risk management systems in construction sites as each title and model, led to risk reduction in construction projects and sites. Also, this is a systematic approach and reasonable alternative to traditional and non-systematic methods used by many contractors. Risk management strategy in the construction industry can lead to efficient and effective results in terms of safety to construction sites including risk avoidance, risk transfer, reduce deaths and injuries, risk prevention and etc. 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, as has been shown in some studies, defects in the HSE management Risk system had allocated a high proportion (84%) in construction accidents. The analysis of occupational accidents and injuries could improve safety and health in the construction industry. Occupational safety and health challenges are tied largely to the construction industry. Various studies have reported catastrophic statistical data despite the many efforts made in this industry to reduce occupational accidents and injuries. The reported injury rate for the construction industry is higher than its average rate across all other industries and workers’ compensation costs of treatment, injuries, and fines in the construction industry are 4 times higher than those in other industries. However, construction workers make up only 5% of the US workforce, this industry accounts for 20% of all work-related deaths and 9% of disabling injuries. 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. However, researchers in various fields have attempted to describe various types of injury to analyze the factors affecting them, the significant point in most of the previous studies is that only some causes of accidents and injuries are addressed and the interaction of these variables are not investigated, nor the path analysis for the incidence of injuries or accidents is provided. 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 RCA (Root Cause Analysis). The use of software modeling approaches that can identify and analyze the relationship between variables and factors involved in the process of causative events as well as identifying the causes of accidents can be useful. 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.

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: Primary data (1328 accidents) were collected. Then, screening was done based on the inclusion/exclusion criteria and finally, 1232 accidents leading to injuries were selected as the final sample of the study.
Step 2: occupational injuries were analyzed based on Root Cause Analysis (RCA). In this analysis, three questions were answered: “What happened?", "how?" and "why?". The executive stages of answering the three questions included a descriptive examination of the injury, sequencing of the events, identifying the factors affecting the incidence, collecting complementary data and identifying the causal chain.
Step 3: Different dimensions of various factors affecting occupational injuries in the construction projects were identified, evaluated and classified. This step aimed at preparing the data for promoting the capability of the conceptual model for structural equation modeling (SEM).
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. It is noteworthy that the structural equation modeling is a general and powerful multivariate analysis technique within the family of multiple regression analysis. In other words, it is the extension of the general linear model that allows a set of regression equations to be simultaneously tested. Structural equation modeling is a comprehensive statistical approach for testing hypotheses about relationships among visible and latent variables. It is called covariance structure modeling, causal modeling or structural equation modeling.

Generally, the results of structural equation modeling showed that occupational injuries are 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. The descriptive results of the factors and variables are shown that the average age and work experience of the injured workers were 6.24 ±33.41 and 3.14 ±5.75 years, respectively. Approximately, two-thirds of the accidents had occurred during construction activities and more than 70% of the accidents had 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). Also, occupational injuries had a significant positive relationship with unsafe conditions, unsafe actions and type of accidents (p <0.05) (Fig. 1). The values of the goodness of fit, χ2/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 is acceptable.

The findings of the study demonstrated that constructional injuries could be affected by a variety of factors and indicator variables with different sizes. Moreover, the application of path analysis approach using structural equation modeling can be a useful method for analysis, modeling, and prediction of occupational accidents and injuries. As the results of this study show, modeling based on path analysis can support the multiple causation theory of occupational accidents. Also, the use of software techniques and models such as SEM shows the correlation and interaction of different variables and factors as well as the numerical degree of their effects on ultimate injuries. This (as an indicator or parameter for decision-making) can contribute to macro safety management in construction projects. The findings of this study showed that 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. For decades, "fall from a height" has been at the top of the list of accident types among construction accidents. Unsafe working conditions in construction projects are among the most important factors in construction injury analysis. Also, as the results of this study show, some factors such as imperfect and weak risk management and organizational factors can contribute to the creation of these unsafe conditions. The results of some studies indicate that a worker or work team is involved in 70% of construction accidents due to human error and unsafe acts. Also, unsafe acts can be influenced by other variables and factors such as individual and demographic factors and safety education. Individual and demographic factors and their indicative variables are among the most important causes of occupational accidents, especially in the construction industry. Among the basic factors associated with occupational accidents and injuries are workplace management and organizational factors including organizational, physical and operational characteristic variables. These variables can cause problems for the safe implementation of the project and affect the events directly or indirectly (under the influence or in interaction with other factors). 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. Some studies have also shown that risk identification and perception can be improved by educational interventions. Accordingly, paying attention to safety education and promoting education indicators will enhance risk perception and identification, improve safety and reduce the incidence of injury on the site. Based on the results, 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. Consequently, the new and different perspective of this study on various variables (in the form of macro organizational factors, safety education and risk management) along with settling the construction affairs including unsafe conditions and unsafe acts, as well as analyzing the type of accident based on the center of incidence represent an important

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. A general overview of the findings of this study shows that inter and intra-factor relationships are always effective in occupational injuries in the construction or any other industrial environment. Therefore, accidents and injuries should be analyzed via modern scientific approaches and techniques and the decisions to increase safety and reduce injuries should be made based on the results of this type of modeling.

Training process is any learning-based activity and experience, performed with the aim of causing relatively fixed and stable changes in people to improve their ability to do a job. In this regard, the apprenticeship course is one of the most important educational courses, especially for action-oriented or practical fields of studies of the universities. In these fields, apprenticeship is considered as an opportunity for experiential learning, acquiring skill, and practical training. This course involves learning during working, practice, practical training, and acquiring skill, which provides an opportunity for students to gain practical experience, apply their skills acquired in the university, improve their management and personal skills, and create new job opportunities. An apprenticeship period is suitable for trail and test under the supervision of academic educators and industry experts. It creates real conditions for the link between industry and university, and a young graduated person is prepared for work in the community. The essential part of the practical skills training occurs during this period. In general, apprenticeship leads to acquiring valuable practical experiences and improving behavior and attitudes. It also prepares them to enter the world of work in graduated people.
Evaluation is one of the most important steps in the training process and the correct implementation of it provides very useful information on the way of planning and implementing educational programs and can be a very useful basis for evaluating educational performance.  In fact, systematic evaluations and interventions based on the results of the evaluation have a direct impact on the improvement of the educational process and the achievement of the educational goals of a field of study.
 Apprenticeship, as other courses, requires evaluation, and it requires a standard and effective tool that can accurately measure the educational and expected goals.  By using such a 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 tool and its psychometric properties is crucial. It can be developed by a group of experts of the same field of the study.
Professional health engineering is one of the important fields of medical sciences. At the bachelor level, apprenticeship is vital in this field of study. This course is considered an essential part of the 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. In this regard, the method of evaluation of apprentices is one of the most important concerns for apprentices and even professors in this field of study. One reason for the importance of this course is the number of its units (16 units), which has a significant effect on the final GPA of students. It is also a concern for other fields of medical sciences. Based on a research conducted by the research team using advice of experts and research resources, it was found that no study had been conducted so far on the evaluation of the apprentices of professional health engineering field of study in Iran. It might be due to the lack of a standard and valid tool to evaluate the apprentices.
 Problems and concerns related to the assessment of field internship course in field of occupation health engineering is one of the most important issues for the students and the proffessors.
This study aimed to development and validating a tool for assessing the field internship course in the field of occupational health engineering.

This study was conducted in the occupational health engineering department of the Faculty of Health 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 and items of tool was developed based on curriculum of internship course in the field of occupational health engineering and using litreture review and panel discussions with the participation of occupational health professors and experts. 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.
In this method used to extract opinions, ideas, and perceptions of a group of people with common characteristics on a particular topic, interviews and group discussions were used. Finally, three areas (dimensions) were defined, which a graduate of this field of the study should be trained based on them. First area: educational and learning

It includes the initial criteria to achieve educational objectives according to the headlines. It is in fact the science and technology that a bachelor student who is being graduated should learn.
Second area: Management and personal skills (behavioral objectives): it is a performance criteria of an apprentice in the behavioral and management section which includes the performances preparing a student for accepting management role of occupational health and related executive actions in the community. Skilled experts consider this area as conventional management and personal skills.
Third area: development of professional job and entrepreneurship competences and qualifications (management objectives): it is a combination of personal and personality traits, skills, characteristics and behaviors that directly affect the performance of an individual. This area is a state of a person's readiness to enter into a particular profession. In other words, it indicates if a person has the ability to do that work and if he or she is able to create value for new situations by creating various opportunities.
 Then, the comprehensive criteria in accordance to these three objectives were prepared. These criteria were determined based on the review of relevant literature, interviews and the use of the experiences of professors and educators in the field of professional health engineering, experts of professional health unit of health centers and professional health experts. 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. Finally, after evaluating the psychometric properties of the questionnaire, 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 in appropriate 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.

Based on the three dimensions defined, in the first step, a three-dimensional 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 effect score 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.
The final version of the tool contained 3 dimensions and 40 items. CVI was 0.85, CVR was 0.76, and IS all items were above 1.5, indicating good content validity from the experts’ points 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.

In general, the positive results of validity of the designed tool suggest the desirable psychometric property of the 40-item questionnaire of evaluation of the apprenticeship course in the field of professional health engineering with three areas 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 health professional engineering field of study. 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 professional health engineering departments of Iran’s medical universities. Finally, a complete and comprehensive tool for evaluating apprentices of this field of study is provided for academic community.
 The results indicated that the field internship course in the Field of occupational health engineering In three dimension, it includes the dimension of educational and learning objectives, the field of managerial and individual skills, as well as the development of professional qualifications and entrepreneurship assessment tool has good psychometric properties and can be used as a standard mseare for assessing the field internship course of student occupational health engineering. The scope of educational and learning objectives, the field of managerial and individual skills, as well as the development of professional qualifications and entrepreneurship.
Keywords: Questionnaire designs, Validity, Reliability, Occupational health.

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).

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.

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.

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.

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 data provides information on static dimensions of the human body in standard postures. 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 a 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.

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.

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.

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.