Journal of Health and Safety at Work

Assessment of ergonomics risk factors influencing incidence of musculoskeletal disorders among office workers

M. Bagheri Hosseinabadi

Background: High prevalence of musculoskeletal disorders have been reported by office workers due to the nature of their work. This study aimed to evaluate the prevalence of musculoskeletal disorders in a group of office workers and also to determine the ergonomics risk factors affecting these disorders.

Methods: This is a cross-sectional study, performed among 174 office workers in Kerman city, Iran. Data collection tools included demographic and organization information form, the Nordic Musculoskeletal Questinnaire (NMQ), and the Rapid Office Strain Assessment (ROSA) method. The gathered data were analyzed by SPSS software version 16 using descriptive statistics, chi-square test, and logistic regression.

Findings: The prevalence of symptoms of musculoskeletal disorders (MSDs) in the past 12 months was reported 60.4 percent. What is more, significant associations were observed between job tenure and hours a day using computer with MSDs (P-value<0.05). In this sense, with one unit increase in job tenure (years) and duration of computer use (hours per day), the probability of incidence of MSDs gone up 17.2 percent and 15.8 percent, respectively. Based on the statistical chi-square test, a significant relationship was reported between the incidence of MSDs and Rapid Office Strain Assessment method (P-value<0.05).

Conclution: According to results, ROSA assessment method is an efficient tool in the classification and identification of factors affecting the incidence of MSDs among office workers. Performing corrective measures in the dangerous work stations (the second level identified by ROSA technique), reducing the duration of computer use per day, and doing regular sport activities can be noted in order to decrease the prevalence of MSDs in the study group (office workers).

Evaluating X-ray absorption of nano-bismuth oxide ointment for decreasing risks associated with X-ray exposure among operating room personnel and radiology experts

H. Shirkhanloo

Introduction: During recent years, carcinogenic effects of X-ray have been proven. Todays, lead is used in many equipment such as coats, thyroid shield, and gloves for body protection against X-ray. However, these equipments have several disadvantegous including toxicity, heaviness, and inflexibility. Hence, newer methods like protective semisolid products (cream, ointment) for topical application are being replaced. Therefore, the feasibility of using an ointment containing bismuth oxide nanoparticles (Bi2O3) as a X-ray adsorbent was evaluated in this study.

Methods and Materials: First, synthesis of Bi2O3 and then formulating it in the form of ointment was investigated. In this study, X-ray device and dosimeter was employed to check the X-ray absorption in different thickness of bismuth oxide nanoparticles ointment.

Results: In dosimetry test, the protective effect of the ointment containing Bi₂O₃nanoparticles was evaluated significantly (P<0.05) better than control group and equal sheet lead group. Dosimetry tests showed that the bismuth oxide nanoparticles ointment and cream absorb 56% of the radiation whereas this value is 41% for lead. K absorption edge for bismuth is higher than other metals and its nanoparticles have more absorbent surface to volume ratio (S/V).

Conclusion: It seems that due to higher atomic number and lower toxicity, Bi₂O₃ nanoparticles have better efficiency in X-ray absorbtion, comparing to the lead. Cream and ointment of bismuth oxide nanoparticles can be used as X-ray absorbant for different professions such as physicians, dentists, radiology experts, and operating room staff and consequently increase health and safety of these employees.

Analysis of accidents leading to amputations associated with operating with press machines, using Ishikawa and SCAT Combined method in a car manufacturing company

M. Nasrabadi

Introduction: By industrialization, work-related accidents emerged as one of the most threatening factors of human life therefore analyzing the causes of accidents and providing control measures to prevent reoccurrence of similar accidents are of crucial importance.

Method and Materials: This is an analytical-descriptive study in which the collected data were analyzed using Ishikawa and SCAT methods and results related to the relationships between variables were examined. In this sense, first, accidents leading to amputations associated with operating with press machines (stuck between two objects) were analyzed by Ishikawa method and the obtained causes were classified into three groups: direct causes, interface causes, and root causes. Then, the obtained causes and the control measures were placed in SCAT table. The effect of causes of accidents and their ranking were determined using Chi-Square Test and Friedman's test, respectively. Accordingly, appropriate control measures were provided based on the accidents causes.

Results: The most significant interface causes is hurry at work the most significant root causes is inappropriate and ineffective supervision and the most important control measures is establishing effective HSE management system in the organization.

Conclusion: According to results, the main interfce causes of accidents leading to amputation due to operating with press machines is hurry at work because of increased production volume particularly by contractor companies. Furthermore, non-dynamic HSE system accompanied by ineffective supervision of personnel’s unsafe acts by the first layers of management are recognized as the basic causes of such accidents.

The impact of traffic noise on mental performance considering complexity of activities

A. Mehri

Introduction: Traffic noise has been thought as a major environmental stress in modern societies, and the cause of physiological and psychological disorders according to the World Health Organization. Moreover, traffic noise can interfere with mental performance. However, there is little coherent evidence showing the effect of traffic noise on individuals’ performance. Hence, this paper aimed to address the role of traffic noise in participants’ mental performance considering the complexity of the activity.

Material and methods: Thirty-five master students studying in Tehran University of Medical Science were recruited for this study. Traffic noise was recorded by tape recorder and the traffic noise level was simultaneously measured by sound meter. Then, participants had been separately sitting in silent compared to traffic noise environment before they performed the tests including “S₃”-type Choice Reaction Time (CRT) test as a simple activity and “S1”-type Determine Test (DT) as a complex activity taken from “Vienna Test System” software package.

Results: The comparison between scores resulted from DT and CRT tests ,before and after exposure to traffic noise under simple activity conditions, showed that there was little increase in mean score of reaction time (P-value=0.47) and motor time (P-value=0.49), showing no statistically significant changes in these variables. On the contrary, following exposure to traffic noise, the DT test under complex activity condition revealed that there is a clear decreasing trend in median reaction time(P=0.001), number of stimuli (P=0.014) and number of reactions (p=0.009) in participants, and also, no significant differences were found in correct responses (P=0.091) and incorrect responses (P=0.073).

Conclusion: One of the most significant findings emerged from this study is that traffic noise seems to have no effect on the mentioned variables under simple activity condition. However, traffic noise has devastating effects on median reaction time, number of appeared stimuli and reactions under complex activity condition.

Investigating the relationship between psychosocial work stressors, organizational structure and job satisfaction among bank tellers

Y. Hamidi

Introduction: Studies have shown that bank clerks experience high levels of stress. Stress is known as the main cause of reduction of job satisfaction and staff commitment and overall organization performance. This study aimed to investigate the association between psychosocial stressors, organizational structure, and job satisfaction.

Methods and Materials: This cross-sectional study was performed in 11 branches of a bank in Hamadan. In order to collect data, General Nordic Questionnaire (QPS Nordic 34+), Organizational Structure and Job Satisfaction Questionnaires were used. For determining the relationship between the two variables spearman correlation coefficient was used. Moreover, chi-square test was used to investigate the association between qualitative variables.

Results: Job stress (57%) and job satisfaction (39%) of the subjects were in the average level, and structure of the majority of the branches was somewhat inflexible (69%). What is more, there was a significant positive correlation between job stress and dimensions of organizational structure (centralization, formalization). Results manifested a significant correlation between organizational structure and job satisfaction (P-value= 0.05).

Conclusion: Considering the effect of organizational structure and work-related psychosocial stressors on job satisfaction, it can be stated that organizational restructuring to achieve organic structures and paying more attention to psychosocial stressors in the workplace, can play an effective role in the efficiency and productivity of the organization.

Comparison of musculoskeletal pain between depressed and non-depressed industrial workers and investigation of its influencing factors

F. Mahmodi

Introduction: In theexperienceof pain,thesensory andthe emotional components should be considered. Emotionalcomponents of the painincludea variety of emotional states which depression is the most importantone. Thus, in this study, first, musculoskeletal pain was compared between depressedand non-depressed industrial workersand then otherphysical anddemographicfactorsinfluencing thedepression andmusculoskeletal disorderwere studied.

Method and material: Thiscross-sectional and descriptive-analytical study was conductedin 2012, among 179 industrial workers in Shiraz city.In this study,the participantswere selected throughcensus.The data collection instruments were three questionnaires including Body Discomfort Chart (BDC), visual analogue scale type, Beck Depression Inventory (BDI) and demographic informationquestionnaire. The collected data were analyzed using SPSSsoftware version 16. Mann-Whitney and Kruskal-Wallis statistical tests wereemployedfor comparison of variables and Kendall correlationwas used for determining the relationship between variables.

Results: Findings of the study showed that the maximum (19%) and the minimum (3.4%) painwere belonged to back and arm/forearm, respectively. Furthermore, 36.2% of participantshad a low-to-acute level of depression. Comparison of musculoskeletal disorders betweendepressed and non-depressed workers with Mann-Whitney Test manifested a significant different in head/neck, back,left hand/wrist,right hip and knee (p<0.05).Also Kruskal Wallis statistical test showed no significant differences in depression levelamong various occupational groups,however, painsignificantly differed among various groupsin a way that its rate was higher for office workers,comparing to other groups.

Conclusion: The higher score of depression among workerswith musculoskeletal pain can be due to failure in pain relief achievement. Psychological problemsthatoccurfollowingchronicpainarerelated to continuous discomfort, frustration and thinking about the pain. This situation causes the feelings of inadequacy and inefficiency and consequently the increase ofprobability of depression.

Relationship between employees' safety climate and safety performance with respect to mediating effect of safety knowledge and safety motivation in Sarcheshmeh copper complex

M. Ziaaldini

Introduction: The present study aimed to investigate the relationship between safety climate and safety performance with respect to the mediating effect of safety knowledge and safety motivation.

Material and method: The study population was a sample of 354 subjects chosen by Cochran formula among all 4252 employee in Sarcheshmeh copper complex in Rafsanjan, 2015. The participants were selected according to stratified random sampling. Data collection was done by four questionnaires (safety climate, safety knowledge, safety motivation, and safety performance).The Cronbach's alpha and composite reliability (CR) were used to evaluate the reliability of the study tools and the coefficient of all variables were acceptable with values of higher than 0.8. Moreover, validity of the questionnaires was confirmed by convergent validity and divergent validity, R-square, effect size (f2), and Q2 criterion. The Average Variance Extracted (AVE) was greater than 0.4 which is relatively acceptable. The obtained data were analyzed using SmartPLS software.

Result: Kolmogorov-Smirnov test was used to investigate the normality status of variables distribution. Furthermore, Structural Equations Method (SEM) was adopted to test the research hypotheses.The results confirmed all the research hypothesis and showed safety climate direct effect on safety performance. Moreover, safety motivation and safety knowledge have mediating role in the relationship between safety climate and safety performance. Safety motivation can also mediate the relationship between safety knowledge and safety performance.

Conclosion: Overall, it is recommended to improve safety climate, considering its influencing components. Employees' safety knowledge and safety motivation should also be promoted. Additionally, it is recommended to determine other personal and organizational parameters and include them into the model. By determining the mediating variables, their role in the safety performance can be investigated.

Ergonomics in Healthcare system-Human Factors models: a review article

S. A. Zakerian

Introduction: The healthcare system is one of the largest sectors in most countries and is a socio-technical system in which people play a preponderant role. Nowadays medical work systems are facing three major challenges: 1) Healthcare costs, 2) Quality and patient demands and 3) complexity of healthcare. These problems show the necessity of applying ergonomic models in the healthcare sector. The aim of this study was to review the practical ergonomic models in healthcare system.

Material and method: For this review article, the authors searched through ScienceDirect, PubMed, ProQuest internet databases from 2005-2014 using the following keywords: Healthcare, Ergonomics, Human factors and model.

Result: Overall, 85 articles were reviewed. By evaluating articles' titles, 30 articles related to the study subject were chosen. Then, reviewing the abstracts resulted in 15 articles and in the final step 5 full-text articles were selected which described practical models of ergonomics in healthcare: 1) SEIPS, 2) DIAL-F, 3) Extended Patient-Staff-Machine-Interaction, 4) Adapted Medical-Task and 5) Recursive Hierarchical Task-Process-Task-Model.

Conclusion: Most of the published studies emphasize on application of ergonomic models in healthcare centers since these models may reduce their problems. These ergonomics approaches support patient-centered treatment processes, user-oriented design of medical environments, efficient utilization of resources and increase motivation of clinical staff.