Prediction of maximal oxygen uptake based on anthropometric indices in Iranian male adults.

BACKGROUND: Assessment of maximal oxygen consumption is important in both general community and occupational settings. Validity and reliability tests are needed to indicate the functionality of the cardiopulmonary system. OBJECTIVE: This study aimed to establish a maximal oxygen consumption (VO2max) prediction model using anthropometric and demographic variables for young adults in Iran. METHODS: This cross-sectional study was conducted on 64 healthy young men aged 19-29 years. Oxygen consumption was measured directly and the prediction models to estimate VO2max were determined by multiple linear regression. The accuracy of the prediction models was considered using regression coefficient (R), coefficient of determination (R2), and standard error of estimate (SEE). RESULTS: The average VO2max was 44.02±4.31 ml/kg/min. Significant correlations were found between the measured VO2max and the anthropometric and demographic variables (r = 0.16-0.86, P < 0.05). Three significant regression models with acceptable accuracy were developed (R2 = 0.67-0.71, SEE = 3.19-3.21). CONCLUSION: The predictive models consisted of 3-5 variables as significant predictors of VO2max and had acceptable accuracy for Iranian young adults. The proposed models are a simple and valid tool that can be used to estimate the VO2max in the field and in laboratory settings.

The Effectiveness of a New Climbing Device on Working Postures, Musculoskeletal Symptoms, and Fatigue in Date Palm Farmers.

BACKGROUND: Musculoskeletal disorders are one of the main health problems found in date palm farmers. This study aimed to assess a new climbing device on working postures, musculoskeletal symptoms, and fatigue in date palm farmers. METHODS: Data were collected using questionnaires (Standardised Nordic Musculoskeletal Questionnaire, Multidimensional Fatigue Inventory, and System Usability Scale) and direct observations of the postures (using the Rapid Entire Body Assessment method [REBA]) from 70 date palm farmers during operating the traditional and new climbing devices. RESULTS: The new climbing device showed significant improvement in working postures (in the knee, legs/ankles, and shoulders). In all tasks, the REBA grand score significantly decreased after using the new climbing device (P ≤ 0.05). Significant differences were found in the severity of complaints ratings, particularly in the knee, legs/ankles, and low back areas, during performance tasks using the traditional and new climbing devices. Also, significant differences were found between the scores of physical and mental fatigue during use of the traditional and new climbing devices(P ≤ 0.05). CONCLUSION: The findings indicate the effectiveness of the new climbing device as a low-cost, simple, and easy-to-use device that improves working postures and reduces musculoskeletal discomfort in date palm farmers.

Work-related stress, self-efficacy and mental health of hospital nurses.

BACKGROUND: The limited research has focused on the relationship between work-related stress and self-efficacy in relation to mental health problems in nurses. OBJECTIVE: This multi-hospital cross-sectional survey investigated the relationships between work-related stress, self-efficacy and mental health status of hospital nurses in Tabriz, Iran. METHODS: Four hundred hospital nurses completed a questionnaire including demographic and job details, Health & Safety Executive (HSE) Management Standards Revised Indicator Tool (MS-RIT), General Self-Efficacy (GSE-10) scale, and General Health Questionnaire (GHQ-28). A three-step hierarchical logistic regression modelling was used. RESULTS: Work-related stress, self-efficacy and mental health problems were significantly related to each other. The results of the regression modelling revealed that working overtime and number of patients cared for were significant positive predictors, while job tenure as well as control and relationships dimensions of work stress were significant negative predictors of mental health problems, with the final model explaining 21% of the variance in the outcome measure. Addition of self-efficacy at step 3 did not result in a significant change in the variance from previous steps. CONCLUSIONS: The results provide further support for stress prevention strategies focused at the job (e.g., better organisation of work demands) and organisational (e.g., improving employee participation and involvement in work) levels.

Metabolic syndrome and its relationship with shift work in petrochemical workers.

BACKGROUND: The metabolic syndrome is a complex of interdependent risk factors for cardiovascular disease and diabetes. Shift work might have an impact on metabolic variables, and be a risk factor for type 2 diabetes. To date, only few studies have been done on the prevalence of MetS in industrial work environments in Iran, and most of them have been conducted on a small sample size. OBJECTIVE: The aim of this study was to evaluate the impact of shift work on prevalence of metabolic syndrome in one of the petrochemical companies in Iran. METHODS: This cross-sectional study was conducted among 692 male workers of a petrochemical company in south-west Iran. Metabolic syndrome was diagnosed according to criteria recommended by Adult Treatment Panel III. In order to determine correlation between MetS and its factors with shift work odds ratio (ORs) for the MetS, 95% confidence level (95% CL), chi-square test and logistic regression analysis were performed. RESULTS: Overall 15.1% of workers were diagnosed with metabolic syndrome and 80% of them were shift workers. A significant difference for prevalence of metabolic syndrome and mean values for body mass index, blood pressure, fast blood sugar, waist circumference among shift workers and non-shift workers were identified (p < 0.001). Compared with the day workers, shift workers had a significantly higher risk of MetS (odds ratio = 4.852; 95% CI 2.34-9.974). CONCLUSIONS: There is an association between metabolic syndrome and shift work in petrochemical workers. Promising intervention strategies are needed for prevention of metabolic disorders for shift workers.

Corrigendum: Psychosocial Factors Associated With Resilience Among Iranian Nurses During COVID-19 Outbreak.

[This corrects the article DOI: 10.3389/fpubh.2021.714971.].

Psychosocial Factors Associated With Resilience Among Iranian Nurses During COVID-19 Outbreak.

Background: In the face of COVID-19, healthcare workers need to cope with the ongoing stressors at play and keep psychological distress at a minimum level. This study examined the psychosocial and demographic factors associated with nurse's resilience in the hospitals of Ahvaz that is one of the top cities infected with COVID-19 in Iran. Methods: The present cross-sectional study was conducted on 387 Iranian nurses in Ahvaz city. For data collection purposes, three online questionnaires (including Copenhagen Psychosocial, Demographic, and Connor-Davidson Resilience Scale) were distributed among the participants. Results: The mean resilience score was equal to 61.8 ± 14.8 for 387 nurses. Resilience had a statistically significant negative correlation with quantitative demand (r = -0.273, P < 0.008), work pace (r = -0.262, P < 0.011), emotional demand (r = -0.226, P < 0.030), stress (r = -0.458, P < 0.000), and burnout (r = -0.287, P < 0.005). Multiple linear regression analysis indicated that stress, job satisfaction, burnout and age were the main predictors of nurses' resilience during the (COVID-19) pandemic (R2 = 0.45). Conclusions: We identified psychosocial and demographic predictive factors that may contribute to greater resilience among nurses during the COVID-19 outbreak. The findings of this study can be used to implement psychosocial interventions to amplify the resilience of medical staff during the COVID-19 outbreak.

Prevalence of metabolic syndrome and its associated factors among Iranian steel workers.

BACKGROUND: Metabolic syndrome (MetS) is composed of a collection of risk factors for heart diseases and diabetes. In recent decades, metabolic syndrome has been identified as one of the important risk factors leading to the development of work-related diseases. OBJECTIVE: Since few studies have been conducted on evaluating the prevalence of MetS among Iranian workers, this cross-sectional study aimed at assessing the prevalence of MetS and the factors affecting it among Iranian steel workers. METHODS: This study was carried out on 510 employees working in a large steel producing company. The data pertaining to blood pressure, triglycerides, cholesterol, glucose, and demographic information were collected and the Adult Treatment Panel (ATP III) criteria were implemented to diagnose MetS. RESULTS: The prevalence of Mets was obtained equal to 13% and a significant positive relationship was observed between age and the prevalence of metabolic syndrome. From among MetS elements, low HDL cholesterol and increased waist circumference were recognized as the most and the least frequently involved elements with 39.3% and 6.5% prevalence, respectively. Chi-square test was run and the results showed that the prevalence of MetS and some of its components rose at higher BMI values. It was also indicated that MetS and its components had no significant relationship with shift work. CONCLUSION: The current findings revealed that the prevalence of MetS increased with aging. Low HDL and high triglycerides levels were among the main risk factors for MetS. Therefore, considering these risk factors, it should be attempted to develop relevant strategies at workplace to encourage workers to go for a healthier lifestyle so that they can prevent the incidence of MetS.

Demographic predictors of resilience among nurses during the COVID-19 pandemic.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is mostly transmitted through respiratory droplets. One of the exposure methods pf this disease is through occupational exposures and, thereby, a large number of people are prone to catching this disease due to their occupations. Nurses during the COVID-19 pandemic are at the forefront of healthcare. There is no information about the level of resilience and the demographic and job factors predicting resilience in the critical conditions of this occupational group. OBJECTIVE: The present study aims to determine the resilience score and its predictive demographic factors among the nurses working at the hospitals involved with COVID-19 in Ahvaz, Iran. METHODS: 387 nurses from Ahvaz hospitals participated in this study. The Connor-Davidson Resilience Scale (CD-RISC) was used to assess resilience. Demographic information was also collected using a designed questionnaire. Since the present study was conducted during the COVID-19 pandemic, the questionnaires were sent online. Data were entered into software SPSS (version 23) and T-test, ANOVA and regression methods were used for data analysis. RESULTS: The mean score of 61.18 (±14.8) was obtained for CD-RISC. The results of this study showed that age (r = 0.610, P = 0.003), work experience (r = 0.572, P = 0.030), and level of education (r = 0.514, P = 0.044) had a significant positive correlation with nurses' resilience score during the COVID-19 pandemic. Multiple regression analysis indicated that work experience and level of education were the predictors of nurses' resilience (R2 = 0.15). CONCLUSION: The score of nurses' resilience was low. Based on the results, education and work experience were determined as the contributing factors for resilience. The findings can help to better understand effective and predictive demographic factors to achieve higher resilience in stressful situations.

Effect of neck posture on cervicothoracic loads in overhead crane operators.

Awkward neck postures are commonly documented to be associated with an increased risk of neck disorders. This study intended to continuously monitor and evaluate neck postures and to estimate the cervicothoracic loads among overhead crane operators during work time. Neck postures were measured among 40 randomly selected operators by an inclinometer during 2 h of work time. To determine the tasks and adapt the posture recordings to each of their corresponding tasks, direct observation was conducted concurrently. The median neck flexion and lateral bend angles were 28.23° and 11.30°, respectively. The mean compression and shear loads on the neck ranged from 75.22 to 113.14 N and from 9.50 to 41.11 N, respectively. The results indicated substantial levels of exposure to awkward and extreme neck postures among the operators. The nature of the operators' work and the visual requirements of some tasks will increase the mechanical loads on the neck.

Evaluation of biomechanical risk factors for neck and back disorders in traditional bakers during a work-day: Implications for ergonomics intervention.

Awkward back and neck postures have been recognized as one common problem in bakery workers. This study aimed to evaluation of the biomechanical risk factors on the back and neck of bakers. Twenty bakers of four types of bread- baking systems were randomly selected. Working postures and movements of the back and neck during work were continuously recorded with inclinometry measurements during three hours. Physical workload in bakers was characterized by awkward postures and the percentage of time spent with the neck flexed more than 20°. Besides, low angular velocity and lack of postural variation during baking shows that bakers' back is in the static position and bakers have to work with constrained back for a long time. The current findings have important implications for prioritizing ergonomic interventions and any ergonomic interventions should be focused on reducing neck flexion and constrained postures of the back.

Physical workload and musculoskeletal disorders in back, shoulders and neck among welders.

This study aimed to determine the effect of the physical workload on the back, neck and shoulders of welders. The prevalence of musculoskeletal symptoms was assessed using the Nordic questionnaire among 15 welders. The physical workload of the neck, back and upper arms was then measured by means of inclinometry as the welders were working. The results revealed that the highest prevalence of musculoskeletal disorders during the previous 12 months was in the lower back and shoulders. The median trunk and neck flexion were significantly associated with back and neck pain in welders with symptoms during the past year (p < 0.05). Physical exposure in welders with pain was characterized by significantly more awkward postures and percentage of time spent with the trunk and neck flexed more than 20°. The nature of their work and the design of their workstations may be causes of the symptoms they experienced during work.

Estimation of Heat Stress and Maximum Acceptable Work Time Based on Physiological and Environmental Response in Hot-Dry Climate: A Case Study in Traditional Bakers.

BACKGROUND: Heat stress is common among workers in hot-dry areas. To take preventive strategies for the protection of workers against heat stress, it is important to choose a suitable index that can accurately explain environmental parameters relative to physiological responses. OBJECTIVE: To evaluate heat stress and maximum acceptable work time (MAWT) based on physiological and environmental response in hot-dry climate among traditional bakers. METHODS: The current study was carried out on 30 traditional bakers of 3 different bread baking systems in Ahvaz, Iran. Environmental and physiological parameters were measured simultaneously for a work shift. The work-rest time was also determined based on the relative heart rate (RHR) and the wet-bulb globe temperature (WBGT) index. RESULTS: The average WBGT index was estimated to be higher than the standard limit for all baking stations. Despite the higher-than-the-recommended-limit WBGT index, there was no significant relationship between the WBGT index and physiological parameters. The results indicated a significant (p<0.05) difference between the percentages of work-rest time estimated using the WBGT and RHR index. CONCLUSION: Based on the results of environmental and physiological monitoring of this study as well as the limitations of the use of the WBGT index, it seems that using WBGT as a standard index would not suit heat stress management in hot-dry climates. A revision of this standard to adapt to hot climatic conditions should be in order.

Awkward trunk postures and their relationship with low back pain in hospital nurses.

BACKGROUND: Low back pain (LBP) is the most common work-related musculoskeletal problem among healthcare workers including nurses. Awkward trunk postures have been recognized as one common problem in this groupOBJECTIVE:The aims of this study were to: a) continuously assess trunk postures for an entire shift work in various hospital wards, and b) examine the relationship between the duration of exposure to awkward trunk postures and the occurrence of low back pain (LBP) among nurses. METHODS: Eighty nurses from eight wards in a hospital participated in this cross-sectional study. The prevalence of LBP was determined using the revised Nordic Musculoskeletal Questionnaire. Full-shift work trunk posture exposure was measured using an inclinometer. RESULTS: The prevalence of LBP among hospital nurses was 72%. The highest percentage of time spent in awkward postures in the sagittal plane (trunk flexion ≥45°) and in the frontal plane (lateral bend ≥20°) was recorded in the general (65.6% ± 12.2) and orthopedic (48.4% ± 7.4) wards, respectively. Logistic regression analyses showed that the duration of exposure to awkward trunk postures had a significant relationship with LBP (P < 0.05). CONCLUSIONS: The results highlight the potential risks of nursing job in terms of frequent and extreme trunk awkward postures, which may lead to the development of LBP. The findings can help to develop guidelines regarding prioritizing ergonomic interventions to reduce the prevalence of LBP among hospital nurses.

Assessment of low back disorders risk based on allowable weight limits for manual lifting in Iran.

In 2011, load limits for manual lifting were adopted in Iran to protect workers from low back injury without prior testing of accuracy with Iranian workers. This investigation examined how accurate the adopted ACGIH TLVs at the allowable limits predict risk for LBP disorders for a group of Iranian workers using biomechanical criteria. Testing took place in the laboratory with participants completing a series of 2-handed lifting tasks as defined in the Iranian Guideline for Manual Lifting. To test accuracy, both compression and shear forces were estimated for fifteen male Iranian workers who completed 25 lift combinations that varied in height and reach with the maximal allowable load. The findings, when compared to a risk threshold of 3400 N compression and 700 N shear, showed above-threshold forces for compression and little-to-no safety margins with repetitive lifting for most lifts at torso height and below. Since Government, employers and workers use these guidelines to decide on work/workplace design; these guidelines require further review and revision based on the anthropometrics of Iranian people.

Full shift assessment of back and head postures in overhead crane operators with and without symptoms.

OBJECTIVES: Prolonged sitting with a flexed back and neck is recognized as being associated with an increased risk of neck and back pain disorders among overhead crane operators. The aim of this study was to compare back and head postures over a full shift of work between operators who experience back and neck pain, and healthy operators. METHODS: In a first phase, the prevalence of musculoskeletal symptoms was assessed using the Nordic questionnaire among 120 crane operators. Based on first phase results, 17 operators with back/neck disorders were matched with 15 healthy operators based on age and selected to participate in the second phase of the study. Postures and movements were continuously measured over an 8 h shift using inclinometers. RESULTS: The highest 12-month prevalence of musculoskeletal disorders was found in the lower back, neck and knees. Case and control groups differed significantly in back and head flexion angles at the 50th percentiles APDF (p < 0.05). There was also a significant difference in the time spent working in an extreme posture of the back and head between groups (p < 0.05). CONCLUSIONS: This is the first study to document work postures assumed during a full work shift and to compare postures between symptomatic and healthy overhead crane operators. Physical exposure in case group operators was characterized by more awkward and extreme postures in the back and head. The results of this study demonstrate that effective prevention strategies directed towards musculoskeletal disorders are required that address awkward work postures for overhead crane operators.

The impact of ergonomics intervention on trunk posture and cumulative compression load among carpet weavers.

BACKGROUND: Work-related musculoskeletal disorders of back among weavers are prevalent. Epidemiological studies have shown an association between poor working postures and back disorders among carpet weavers. Therefore, the present study aimed to evaluate the impact of the traditional (A) and ergonomically designed (B) workstations on trunk posture and cumulative compression load in carpet weavers. METHODS: In this study, subtasks were identified in terms of stressful postures and carpet weaving process. Postural data were collected during knotting and compacting subtasks using inclinometer during four hours for each workstation. Postural data, weight and height of the weavers were entered into the University of Michigan three-dimensional static biomechanical model for estimation of the compression load and cumulative load were estimated from the resultant load and exposure time. PARTICIPANTS: Thirteen healthy carpet weavers (four males and nine females) participated in the study. RESULTS: Median trunk flexion angle was reduced with workstation B during knotting subtask (18° versus 8.5°, p< 0.01 in males; 18.5° versus 7°, p< 0.001 in females). Average cumulative compression load was reduced with workstation B (22.17MN-s versus 16.68MN-s, p < 0.01 in males; 13.05 MN-s versus 10.14, p < 0.001 in females). CONCLUSIONS: Using workstation B led to significant decrease in cumulative compressive loading during an entire shift (8 hours), which indicates reduced level of stress on the back. It is suggested to conduct biomechanical studies on the shoulder and wrist regions in carpet weavers in order to achieve further development and improvement in the ergonomically designed workstation.

The Impact of Ergonomically Designed Workstations on Shoulder EMG Activity during Carpet Weaving.

BACKGROUND: The present study aimed to evaluate the biomechanical exposure to the trapezius muscle activity in female weavers for a prolonged period in the workstation A (suggested by previous studies) and workstation B (proposed by the present study). METHODS: Electromyography data were collected from nine females during four hours for each ergonomically designed workstation at the Ergonomics Laboratory, Hamadan, Iran. The design criteria for ergonomically designed workstations were: 1) weaving height (20 and 3 cm above elbow height for workstations A and B, respectively), and 2) seat type (10° and 0° forwardsloping seat for workstations A and B, respectively). RESULTS: The amplitude probability distribution function (APDF) analysis showed that the left and right upper trapezius muscle activity was almost similar at each workstation. Trapezius muscle activity in the workstation A was signifi-cantly greater than workstations B (P<0.001). CONCLUSION: In general, use of workstation B leads to significantly reduced muscle activity levels in the upper trapezius as compared to workstation A in weavers. Despite the positive impact of workstation B in reducing trapezius muscle activity, it seems that constrained postures of the upper arm during weaving may be associated with musculoskeletal symptoms.

Continuous assessment of back and upper arm postures by long-term inclinometry in carpet weavers.

Awkward back and shoulder postures have been suggested to be a cause of back and shoulder discomfort in carpet weavers. This study aimed at continuous assessment of the upper arm and back postures and estimation of biomechanical load subtasks using inclinometers during 4 h. Median of trunk flexion angle in weavers was 18° and 13° during knotting and compacting subtasks, respectively. The weavers worked with arms elevated greater than 45° for %4.5 of the work time. The average cumulative compression load for males and females were estimated at 22 MN-S and 13 MN-S, respectively. In addition to poor workstation design, constrained posture of the trunk and low elevation and velocity for both arms may be the main risk factors for developing fatigue and disorders in the back and shoulder regions among carpet weavers. Therefore, any ergonomic interventions should be focused on reducing trunk flexion and the constrained postures of weavers.