Determining the effect of environmental factors, work postures and mental workload on musculoskeletal disorders in rescue workers and accidents of one of the water and sewage companies in Iran

BACKGROUND

Musculoskeletal disorders are one of the most important problems faced by ergonomists today.

OBJECTIVE

This study was conducted with the aim of investigating the effect of weather conditions, working conditions and mental workload on musculoskeletal disorders of rescuers and water and sewage company accidents in hot and cold seasons.

METHODS

The present study was a longitudinal study that was performed on all employees of rescue and disaster teams of Shiraz Water and Sewerage Company in Iran (184 people) by census. Demographic and Nordic questionnaires, NASA Load Index (NASA-TLX), work environment assessment with temperature screening checklist and workplace ergonomic risk factor (WERA) assessment method were performed by the researcher. The collected data were analyzed using SPSS version 23 software and parametric and non-parametric statistical tests.

RESULTS

The results showed that the highest and lowest prevalence of musculoskeletal disorders related to knee and back in winter and thigh in summer with prevalence of 57.1, 55.4 and 6% . The comparison of exposure to heat stress factors in summer and winter seasons showed that the temperature factors and work clothes of the workers in both seasons are in worse conditions than other factors (P <  0968). The results of the mental workload of people in two seasons showed that the highest and lowest mental workload is related to physical changes in the winter season and frustration in the summer season, and this relationship was significant (P <  0.001). Using multiple logistic regression model, the potential risk factors for musculoskeletal injuries including age, height, BMI, level of education and work experience in both hot and cold seasons were compared. The results showed that in summer, work experience (OR = 1.16 (1.06-1.28.)) and height (OR = 1.03(0.98-1.08) had a direct effect on the prevalence of pain and discomfort arranged in the back areas. One year of increase in work experience significantly increases the chance of a disorder in the back by 16% and a one centimeter increase in height increases the chance of a disorder in the lumbar region by 3%, although this relationship is significant.

CONCLUSION

It is recommended that suitable solutions such as using appropriate and up-to-date mechanical tools, reducing activity time, increasing rest time, increasing the number of personnel in order to reduce mental workload, using work clothes suitable for the season and type of work, and ergonomics training for workers are on the agenda of company officials. Water and sewage should be placed.

Investigating the effect of workwear textile modification with nanometal-embedded PMMA polymer by a spray method on textile air permeability, bending stiffness and surface temperature induced by near-infrared

Objectives. This study aimed to optimize modification of cotton-polyester textiles of workwear in terms of air permeability (AP), bending stiffness (BS) and near-infrared (NIR) reflectance using nanometal-embedded polymethyl methacrylate (PMMA) polymer by a spray method. Methods. This experimental study was carried out to modify cotton-polyester textiles using nanoparticles of aluminum oxide (Al2O3), tin oxide (SnO) and zinc oxide (ZnO) embedded in PMMA polymer with different weight percentages by a spray method under 215-psi pressure. The surface temperature of the textiles induced by the NIR spectrum and their comfort in terms of AP and BS were measured according to Standard No. ASTM D737 and BS 3356, respectively. Results. Cotton (65%)-polyester (35%) textiles can be modified with a PMMA-based aluminum and zinc nanoparticle composite with equal weight percentage using a pressurized spray method with good durability. Also, most NIR reflection is in the textile coated with aluminum and ZnO nanoparticle composite in the PMMA base. Conclusions. It is recommended that this composite be used in future studies to impregnate the clothing textile of outdoor workers in hot and arid regions by a spray method under pressure and its effects be investigated on reducing heat stress in these workers.

Effect of temperature reduction of the prefrontal area on accuracy of visual sustained attention

Objectives. Detection of sensitive signs in many work environments with automated systems (aviation industry, flight safety tower, maritime industry, monitoring in the military industry, etc.) is essential and requires constant visual attention. Therefore, the aim of this study was to investigate the effect of forehead cooling on the accuracy of stable visual attention. Methods. This interventional study was performed on 34 male students. The sampling method was a randomized block design. Subjects were assessed by demographic questionnaire, Snellen chart, Spielberger state-trait anxiety inventory (STAI) and physiological and cognitive measurements. Results. Prefrontal cortex (PFC) cooling caused significant changes in sublingual temperature during four measurements in the intervention group. There were no significant changes in heart rate, diastolic blood pressure and saturation of peripheral oxygen (%SpO2) between the two groups. The critical flicker frequency (CFF) as an indicator of cognitive fatigue showed that cognitive improvement after PFC cooling occurred following a reduction in cognitive fatigue. Conclusions. Considering the importance of choosing non-invasive methods to improve the operator's cognitive skills while performing cognitive tasks in the field of neuroergonomics, it can be concluded that PFC cooling is an effective and safe way to improve some cognitive skills such as visual attention.

An observational study to assess circulating nurses' non-technical skills

BACKGROUND

Non-technical skills are cognitive and social skills that are necessary for safe and efficient practices in operating theatre. These skills are inseparable parts of circulating nurses' duties and help them have a good performance during surgical processes. Circulating nurses' non-technical skills have not been closely measured, and much uncertainty still exists about the quality of their skills. This study aimed to assess circulating nurses' non-technical skills.

METHODS

A cross-sectional study was conducted on 300 circulating nurses who worked in four public hospitals in Iran, during 2020. The data of demographics of the studied population were collected using a demographic questionnaire. Kalantari et al's Circulating Practitioner's List of Non-Technical Skills was used to assess the circulating nurses' non-technical skills.

RESULTS

The situational awareness domain had the highest score, while leadership was the domain with the lowest mean score. There was a moderate positive relationship between the mean score of non-technical skills and the number of working years as a circulating nurse.

CONCLUSION

Although the circulating nurses had a moderate level of non-technical skills, they had low scores in several behaviours. However, they did well in some other behaviours. Educational interventions and policymaking solutions can help improve circulating nurses' non-technical skills.

Investigating the short-term effects of using full-body hospital personal protective equipment and changes in physical workload intensity on human physiological and cognitive performance

The present study investigated the short-term effects of using Personal Protective Equipment (PPE) and physical workload intensity on human physiological and cognitive performance among 21 males and 19 females. PPE1 consisted of a medical coverall and surgical mask, while PPE2 consisted of impermeable full-body coverall, shoe covers, latex gloves, N95 mask, and face shield. Objective assessments were heart rate, energy expenditure, core body temperature, clothing microclimate temperature and humidity, and cognitive performance were the continuous performance test and N-Back test. Subjective assessments included thermal sensation, perceived fatigue/skin wetness/clothing moisture. Using PPE2 and increased workload intensity significantly increased the values of all physiological parameters and the subjective ratings of fatigue, thermal sensation, skin wetness, and clothing moisture. Moreover, the participants' cognitive performance was not affected by the type of PPE.Practitioner summary: Healthcare workers are at the highest risk in the fight against pandemics. Therefore, these people are required to use personal protective equipment. Using this equipment may have difficulties. The results show physiological strain and higher subjective ratings associated with using full-body hospital PPE and increased physical workload.

Application of the HEART method to enhance patient safety in the intensive care unit

BACKGROUND: The intensive care unit (ICU) is a complex, dynamic, high stress and time-sensitive place. While a variety of rules and regulations provided to reduce medication errors in recent years, many studies have emphasized that medication errors still happen. OBJECTIVE: The purpose of this investigation is to predict, reveal and assess medication errors among surgical intensive care unit (SICU) nurses. METHODS: This study was performed in one of the public hospitals in Shiraz, namely Shahid Faghihi hospital. The human error assessment and reduction technique (HEART) method was adopted to measure and assess medication errors in the ICU. RESULTS: Findings indicate that ICU nurses perform 27 main tasks and 125 sub-tasks. The results also showed that setting and using DC shock task has the highest human error probability value, and assessment of patients by a nutritionist has the lowest human error probability value. CONCLUSION: Medical errors are key challenges in the ICU. Therefore, alternative solutions to mitigate medication errors and enhance patient safety in the ICU are necessary. Although the technique can be used in healthcare; there is a need to localize the coefficients and definitions to achieve more accurate results and take appropriate controls. Employing experienced people and providing conditions that reduce the possibility of errors in nurses, increasing the number of staff, and developing specialized and simulated training were identified as the most important control strategies to reduce errors in nurses.

Evaluation of oxidative stress and biochemical biomarkers, and psychological parameters in cement plant workers

The cement industry is one of the main world industries with exposure to a wide range of hazardous chemical and physical occupational agents that may increase free radicals and lead to disease. The aim of this study was to evaluate oxidative stress, biochemical markers, and psychological parameters among cement plant workers. In this cross-sectional study, 40 workers exposed to cement and 40 office employees were selected as the exposed and non-exposed groups, respectively. Exposure to cement dust, silica, and noise were, respectively, assessed using the NIOSH 0600, NIOSH 7601, and noise dosimetry methods. Oxidative stress biomarkers including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), and biochemical parameters were measured in the serum of all participants. Depression, anxiety, and stress were assessed by the Depression Anxiety Stress Scales (DASS-21) questionnaire. The results demonstrated that the level of MDA as a marker of oxidative stress was significantly higher in the exposed group. The level of antioxidant enzymes including SOD and CAT were also significantly higher in the exposed group. The level of TAC was lower in the exposed group, but the difference was not statistically significant. The levels of alkaline phosphatase (ALP), aspartate transaminase (AST), and the scores of depression and stress were also significantly higher in the exposed group. According to our results, noise, cement dust, and silica exposure were associated with oxidative stress, and this may be one of the mechanisms in which they adversely affect liver function and mental health.

Hemato-Biochemical Responses Of Rats Co-Exposed To Heat Stress And Trichloroethylene Vapors

Aim — The present study was aimed to measure some hemato-biochemical parameters of male Sprague-Dawley rats co-exposed to different levels of heat stress and Trichloroethylene (TCE) exposure. Methods — All male rats were randomly divided into nine equal groups of 5 animals each. They were exposed to heat stress and TCE vapors in a subacute manner (8 hr/day for 10 days) according to experimental design. Blood samples were taken from the heart of all animals at the end of the 10th day of exposure. Hematology and biochemical parameters were determined using the automated hematology analyzer and an automated biochemistry, respectively. Results — The values of WBC, RBC and HB significantly decreased after co-exposure 250 ppm TCE and extreme heat stress; although, this exposure condition lead to statistically significant increase in mean levels of MCV, RDW, ALP, CPK and LDH. Our findings indicated that there were the subtractive and independent interactions for the hematological parameters and the additive, subtractive and independent interactions for biochemical parameters based on the exposure level to trichloroethylene and heat stress. Conclusion — Heat stress may increase sensitivity of workers to trichloroethylene and the simultaneous effects of exposure provide the circumstances for the occurrence of a variety of disorders.

Understanding the role of oxidative stress in the incidence of metabolic syndrome and obstructive sleep apnea

BACKGROUND

Understanding the causes and risk factors of metabolic syndrome is important for promoting population health. Oxidative stress has been associated with metabolic syndrome, and also obstructive sleep apnea. These are two diseases which have common prognostic characteristics for heart disease. The aim of this study was to examine the role of oxidative stress in the concurrent presence of metabolic syndrome and obstructive sleep apnea in a working population.

METHODS

Participants were 163 artisan bakers in Shahroud, Iran, routinely exposed to significant heat stress and other oxidative stress indicators on a daily basis as part of their work. Using a cross-sectional design, data relevant to determining metabolic syndrome status according to International Diabetes Federation criteria, and the presence of obstructive sleep apnea according to the STOP-Bang score, was collected. Analyses included hierarchical binary logistic regression to yield predictors of the two diseases.

RESULTS

Hierarchical binary logistic regression showed that oxidative stress - alongside obesity, no regular exercise, and smoking - was an independent predictor of metabolic syndrome, but not obstructive sleep apnea. Participants who were obese were 28 times more likely to have metabolic syndrome (OR 28.59, 95% CI 4.91-63.02) and 44 times more likely to have obstructive sleep apnea (OR 44.48, 95% CI 4.91-403.28). Participants meeting metabolic syndrome criteria had significantly higher levels of malondialdehyde (p <  0.05) than those who did not. No difference in oxidative stress index levels were found according to obstructive sleep apnea status.

CONCLUSIONS

Our findings suggest that oxidative stress contributes to the onset of metabolic syndrome, and that obstructive sleep apnea is involved in oxidative stress. Whilst obesity, exercise, and smoking remain important targets for reducing the incidence of metabolic syndrome and obstructive sleep apnea, policies to control risks of prolonged exposure to oxidative stress are also relevant in occupations where such environmental conditions exist.

Designing and Fabricating Nano-structured and Micro-structured Radiation Shields for Protection against CBCT Exposure

Researchers have always been interested in finding new and effective materials for protection against radiation. This experimental study aimed to design and fabricate new types of nano-material and micro-material based shields against the ionizing effect of cone beam computed tomography (CBCT) X-rays. To fabricate a flexible prototype, we added dioctyl phthalate (DOP) oil to emulsion polyvinyl chloride (PVC) powder. The paste was mixed and dispersed. Then, nano- and micro-powders of WO₃ and Bi₂O₃ were added to the paste, with the weight ratio of 20% PVC, 20% DOP, and 60% nano- and micro-metals. Using an ultrasonic mixer, the polymer matrix and metals were mixed and a paste with a thick texture was developed. The resultant paste was poured into glass molds and the molds were then heated in an oven. After cooling, the resultant sheets were selected for further experiments. A CBCT unit and dosimeter were used to evaluate the characterization and X-ray shielding properties of the fabricated prototypes. The half-value layers (HVL) for nano-WO₃, micro-WO₃, nano-Bi₂O_3, and micro-Bi₂O₃ were 0.0390, 0.0524, 0.0351, and 0.0374 cm, respectively. In addition, the linear attenuation coefficient (µ) for these materials were 17.77, 13.20, 19.71, and 18.5 cm⁻¹, respectively. The findings indicate that nano-structured samples are more effective in the attenuation of X-ray energy. The nano-structured WO₃ prototype was nearly 34% more efficient in attenuating radiation compared to the micro-structured WO₃ prototype. This difference in nano- and micro-structured Bi₂O₃ prototypes was 6.5%.

Comparison of Different Heat Stress Indices for Assessing Farmers' Exposure to Heat Stress

The article's abstract is no available.  

The influence of ergonomic breastfeeding training on some health parameters in infants and mothers: a randomized controlled trial

Background

Breastfeeding is considered as a protective factor against non-communicable diseases in infants and mothers. The first aim of this study was to assess the influence of ergonomic breastfeeding training on the infants’ growth. The second aim was to investigate the effectiveness of this training for improving musculoskeletal disorders in mothers.

Methods

In this randomized control trial, 104 participants who were referred to the health centers in Shiraz for breastfeeding care were randomly allocated into the intervention or comparison group using a size-four block sampling method. At birth, 2, 4, and 6 months later childbirth, Rapid Upper Limb Assessment was used to assess musculoskeletal disorders in participants, and the severity of their discomfort was measured with the Visual Analog Scale. During the 6 months of the study (March to September, 2017), the weight and height of the neonates were measured every 2 months.

Results

Significant differences were found between groups in the priority level for corrective action in mothers’ postures determined by Rapid Upper Limb Assessment at 2, 4 and 6 months after childbirth (p < 0.001). Based on the Visual Analog Scale results in mothers at 6 months after childbirth, fewer back pain was reported by the intervention group (p = 0.03). No significant difference were found in the infants^’ weights and heights in boys and girls at all growing stages between the two study groups (p > 0.05). However, the mean height for age of the girl infants at age of 6 months was higher among intervention groups compared to the controls (p = 0.01).

Conclusion

This study demonstrated that ergonomic breastfeeding training reduced the incidence of musculoskeletal disorders in mothers but seems not to have any significant and consistent impact on the infants’ growth.

Trial registration

fa.irct.ir IRCT2014042317398N1.

Autonomic Nervous System Responses to Whole-Body Vibration and Mental Workload: A Pilot Study

Background:

Whole-body vibration (WBV) and mental workload (MWL) are common stressors among drivers who attempt to control numerous variables while driving a car, bus, or train.

Objective:

To examine the individual and combined effects of the WBV and MWL on the autonomic nervous system.

Methods:

ECG of 24 healthy male students was recorded using NeXus-4 while performing two difficulty levels of a computerized dual task and when they were exposing to WBV (intensity 0.5 m/s2; frequency 3–20 Hz). Each condition was examined for 5 min individually and combined. Inter-beat intervals were extracted from ECG records. The time-domain and frequency-domain heart rate variability parameters were then extracted from the inter-beat intervals data.

Results:

A significant (p=0.008) increase was observed in the mean RR interval while the participants were exposed to WBV; there was a significant (p=0.02) reduction in the mean RR interval while the participants were performing the MWL. WBV (p=0.02) and MWL significantly (p<0.001) increased the standard deviation of normal-to-normal intervals with a moderate-to-large effect size. All active periods increased the low-frequency component and low-frequency/high-frequency ratio. However, only the WBV significantly increased the highfrequency component. A significant (p=0.01) interaction was observed between the WBV and MWL on low-frequency component and low-frequency/high-frequency ratio.

Conclusion:

Exposure to WBV and MWL can dysregulate the autonomic nervous system. WBV stimulates both sympathetic and parasympathetic nervous system; MWL largely affects sympathetic nervous system. Both variables imbalance the sympatho-vagal control as well.

The effects of screen light filtering software on cognitive performance and sleep among night workers

Background: Previous studies have reported impaired performance, sleepiness and sleep deprivation among night workers. The purpose of this study was to investigate the effect of color screen Light Filtering software on cognitive performance, alertness and sleep quality among night shift operators of a medical emergency operations center.

Methods: This field trial interventional study was carried out among 30 nightshift operators of shiraz emergency control center. The baseline assessments were carried out under the existing computer screen light conditions in the week preceding the installation of f.lux software. The same measurements were repeated again 4 weeks after installing the software. The cognitive performance of the participants was measured using continuous performance test (CPT) and n-back, while their sleep quality was assessed through Pietersburg Sleep Quality Index (PSQI). Further, to assess their subjective and objective alertness, Stanford sleepiness index and go/nogo test were used, respectively.

Results: The results of this study showed that Screen Light Filtering software significantly increased subjective (P<0.001) and objective alertness (P<0.05). Additionally, the performance of the working memory (P=0.008) and sleep quality (P=0.008) improved significantly after the intervention.

Conclusion: The results revealed that using Screen Light Filtering software is an effective and low-cost method to improve sleep quality and cognitive performance since it filters the short wavelength part of the spectrum and helps body adaptation.

Respiratory Exposure to Toxic Gases and Metal Fumes Produced by Welding Processes and Pulmonary Function Tests

Background:

Welding is a common industrial process and is harmful to welders' health.

Objective:

To determine the effect of toxic gases and metal fumes produced during 3 welding processes on welders' incidence of respiratory symptoms and pulmonary function.

Methods:

This cross-sectional study was conducted in an Iranian shipbuilding industrial factory in 2018. Using the simple census method, 60 welders were selected as the exposed group. 45 staff members of the administrative unit were also recruited to be served as the control group. Welders' demographic data and respiratory complaints were collected employing a questionnaire. Fumes and gases produced were sampled from the welders' respiratory tract and analyzed by standard methods suggested by the National Institute of Occupational Safety and Health (NIOSH). Pulmonary function test was also performed for each participant.

Results:

The prevalence of respiratory symptoms in all welders was significantly (p<0.05) higher than the control group. The mean FVC, FEV1 and FEV1/FVC measured in welders involved in all 3 processes were significantly lower than those recorded in the control group. The spirometry pattern in welders involved in flux cored arc welding and shielded metal arc welding was obstructive; that in those involved in gas metal arch welding was mixed (obstructive and restrictive pattern).

Conclusion:

Exposure to welding fumes and gases was associated with pulmonary function deterioration. Welders involved in gas metal arch welding had a prevalence of pulmonary disorders compared with those involved in gas metal arch welding and flux cored arc welding.

Toxic effects of subacute inhalation exposure to trichloroethylene on serum lipid profile, glucose and biochemical parameters in Sprague-Dawley rats

The current study evaluated the inhalation toxicity of trichloroethylene (TCE) at 0, 10, 100, 250 and 400 ppm in Sprague-Dawley rats for 10 day period, because the subacute inhalation toxicity of TCE on serum lipid profile, glucose and some biochemical parameters has not been previously reported. TCE vapors were generated using the dynamic generation system based on evaporation method in the exposure chamber. On the basis of the results, mean serum low-density lipoprotein (LDL) and albumin (ALB) decreased significantly in all the groups exposed to TCE compared with the control group (p < .005), but there was a significant increase for parameters: fasting blood glucose (FBG) and alkaline phosphatase (ALP) (p < .005). Rats exposed to 400 ppm TCE showed a significant decrease in serum cholesterol (CHOL) and protein (Pr) compared with the control group (p < .005). A negative relationship was found between triglycerides (TG), very low density lipoprotein (VLDL), CHOL, LDL, Pr, ALB and urea levels and the subacute exposure to concentrations of TCE (R² = -0.26, p < .05), but there was a direct correlation for parameters FBG, ALP and alanine aminotransferase (ALT) (R² = 0.42, p < .05). In conclusion, studies with Sprague-Dawley rats demonstrated that subacute inhalation exposure to TCE (≥ 100 PPM) is associated with biochemical and lipotoxicity in the form of decreased serum ALB and LDL and raised ALP and glucose levels. The present study also provides additional evidence relating to decreased serum CHOL and Pr after subacute inhalation exposure to 400 ppm TCE.

Harmful Outcome of Occupational Exposure to Petrol: Assessment of Liver Function and Blood Parameters among Gas Station Workers in Kermanshah City, Iran

Background:

Petrol is an integral ingredient in industrial world. According to the US Agency for Toxic Substances and Disease Registry, there are typically more than 150 chemicals in petrol, including small amounts of benzene, toluene, xylene, ethyl benzene, and trace amounts of some contaminants, such as lead. The aim of this study was to measure the possible deleterious effect of long-term exposure to petrol on blood parameters and liver function.

Methods:

This is a case–control study conducted on 160 participants. Among them, 80 participants worked in a gas station for at least 4 years and 80 participants appeared with no history of occupational exposure to petrol. Blood sample was taken at the time of admonition to the tardive office at each station at 10 AM to measure the association of number of total and differential leukocyte and liver functions.

Results:

Based on the results, significant reduction in total leukocyte numbers was found in exposed group compared to unexposed group (1347 ± 4.59, <0.001). However, there was a significant increase in neutrophil (75.9 ± 3.50 in exposed group compared with 58.9 ± 3.15 among unexposed group, P < 0.001). However, no significant difference was found in liver enzymes between both groups.

Conclusions:

Long-term exposure to petrol fumes has deleterious effect on white blood cells. A significant reduction in the number of total and differential lymphocyte seems to be attributed to the toxic effect of petrol ingredients.

Evaluation of environmental heat stress on physiological parameters

BACKGROUND

Thermal component of the atmospheric environment is an important issue which is related to human's health. Thermal environment includes both heat exchange conditions (stress) and the physiological response (strain). The aim of this study was to measure the association of heat indices (PSI, HSI, Humidex) especially subjective one (STI) with some physiological parameters (Blood pressure, pulse rate and skin temperature).

METHODS

This is a cross-sectional study conducted on 387 male farmers on Boukan, West Azerbaijan, Iran in 2016. Sampling was conducted on the hottest days in summer on July based on the meteorological report. Heat parameters was measured 3 times in each session.

RESULTS

Direct associations were found between heat indices and physiological parameters except systolic BP. However, invers associations were found between blood pressure, skin and core body temperature, pulse rate with all heat indices. Based on the results of linear regression analysis, significant association was found between WBGT and skin temperature (B = 0.31, CI: 0.02, 0.61, P = 0.03). Results also showed significant association between Humidex and skin temperature (B = 0.21, CI: -0.03, 0.40, P = 0.02). However, no significant associations were found between other heat stress indices including UTCI, PHS, HIS, STI and Humidex with all study physiological parameters (core body temperature, systolic and diastolic blood pressure and also pulse rate).

CONCLUSION

As expected, farmer's health is affected by physiological parameters. Moreover, among assessed types of heat stress indices WBGT and Humidex were more powerful to show better the association with mentioned physiological parameters.

Maximal Oxygen Consumption, Respiratory Volume and Some Related Factors in Fire-fighting Personnel

Background:

Firefighters for difficult activities and rescue of damaged people must be in appropriate physical ability. Maximal oxygen capacity is an indicator for diagnosis of physical ability of workers. This study aimed to assess the cardiorespiratory system and its related factors in firefighters.

Methods:

This study was conducted on 110 firefighters from various stations. An self-administered questionnaire (respiratory disorders questionnaire, Tuxworth-Shahnavaz step test, and pulmonary function test) was used to collection of required data. Average of humidity and temperature was 52% and 17°C, respectively. Background average noise levels were between 55 and 65 dB. Data were analyzed using SPSS software (version 19).

Results:

The mean age of the study participants was 32 ± 6.2 years. The means of forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and FEV1/FVC were 92% ±9.4%, 87% ±9.2%, and 80% ±6.1%, respectively. The participants’ mean VO₂-max was 2.79 ± 0.29 L/min or 37.34 ± 4.27 ml/kg body weight per minute. The results revealed that weight has a direct association with vital capacity (VC), FVC, and peak expiratory flow. In addition, height was directly associated with VC, FVC, and VO₂-max (P < 0.05). However, there was an inverse and significant association between height and FEV1/FVC (r = −0.23, P < 0.05). Height, weight, body mass index, and waist circumference were directly associated with VO₂-max.

Conclusions:

The findings of this study showed that the amount of maximum oxygen consumption is close with the proposed range of this parameter among firefighters in other studies. Furthermore, the results of the study revealed that individuals had normal amounts of lung volume index. This issue can be attributed to the appropriate usage of respiratory masks.

Factors associated with work ability index (WAI) among intensive care units' (ICUs') nurses

Objectives:

Work ability is a crucial occupational health issue in health care settings where a high physical and psychosocial work capacity is required and a high risk of disabling injuries and illnesses is predictable. This study aims to examine the association between the work ability index (WAI) and individual characterizations, workload, fatigue, and diseases among intensive care units' (ICUs') nurses.

Methods:

The study sample included 214 nurses selected by a random sampling method from a target population consisting of 321 registered nurses working in eight ICUs. Multiple linear regression analysis was used to test the association between WAI scores and each of the independent variables.

Results:

Results of multivariate analysis revealed a strong and negative association between WAI scores and diseases (B=-5.82, 95% CI=-7.16, -4.48, P<0.001). Among the studied individual characterizations, body mass index (BMI) was significantly and inversely associated with WAI scores. A significant and negative association was also found between WAI scores and dimensions of MFI-20, such as general fatigue (B=-0.31, 95% CI=-0.53, -0.09, P=0.005) and physical fatigue (B=-0.44, 95% CI=-0.65, -0.23, P<0.001). From dimensions of workload, frustration (B=-0.04, 95% CI=-0.07, -0.02, P<0.001) and temporary demand (B=-0.04, 95% CI=-0.08, -0.0001, P=0.04) showed a negative and significant association with WAI scores, while performance showed a positive and significant association (B=0.04, 95% CI=0.01, 0.07, P=0.005).

Conclusions:

Based on the study findings, development of health care programs with the aim of setting up a healthy work environment characterized by a well-structured preventive attitude toward controlling diseases, and a well-designed organizational framework toward increasing the level of performance and motivation, reducing the level of fatigue, as well as reducing the workload, is necessary to promote work ability among ICUs' nurses.

Are Supplementation of Omega-3 and Ascorbic Acid Effective in Reducing Oxidative Stress and Depression among Depressed Shift Workers?

BACKGROUND

This study assessed the effect of supplementation of omega-3 fatty acids and ascorbic acid alone and in combination on the level of lipid peroxidation (malondialdehyde, MDA concentration), total antioxidant capacity (TAC) and depression scores in depressed rotational shift workers in the Tehran Shahid Tondgoyan Oil refinery.

MATERIAL AND METHODS

In this randomized, double-blind, placebo-controlled trial, 136 men who met the inclusion and exclusion criteria and had a Beck Depression Inventory (BDI) score ≥ 10 were selected. Among the participants, 33 received omega-3 fatty acid soft gel (1000 mg twice daily) with vitamin C (250 mg twice daily) (group 1), 31 took omega-3 fatty acid supplements and vitamin C placebo (group 2), 30 took omega-3 fatty acid supplement placebo and vitamin C (group 3), and 32 received omega-3 fatty acid supplement placebo and vitamin C placebo (group 4) for 2 months. Measured were serum MDA, TAC concentrations, and BDI scores at baseline and after 2 months.

RESULTS

This study showed that the BDI score was reduced significantly in all 4 groups, however, the level of decrease was more in the omega-3 fatty acid (alone) supplementation group (mean 6.29 score decrease) (p < 0.001). MDA level decreased significantly in groups with omega-3 fatty acids (mean 0.78 μmol/L ± 1.64 μmol/L decrease) (p = 0.014) or vitamin C supplementation alone (mean 0.74 μmol/L ± 1.55 μmol/L decrease) (p = 0.014), but not in combination.

CONCLUSIONS

Supplementation of omega-3 fatty acids alone and not in combination with vitamin C had a better impact on depression and MDA level pronounced in depressed male shift workers.

The Effect of Exposure to High Noise Levels on the Performance and Rate of Error in Manual Activities

INTRODUCTION

Sound is among the significant environmental factors for people's health, and it has an important role in both physical and psychological injuries, and it also affects individuals' performance and productivity. The aim of this study was to determine the effect of exposure to high noise levels on the performance and rate of error in manual activities.

METHODS

This was an interventional study conducted on 50 students at Shiraz University of Medical Sciences (25 males and 25 females) in which each person was considered as its own control to assess the effect of noise on her or his performance at the sound levels of 70, 90, and 110 dB by using two factors of physical features and the creation of different conditions of sound source as well as applying the Two-Arm coordination Test. The data were analyzed using SPSS version 16. Repeated measurements were used to compare the length of performance as well as the errors measured in the test.

RESULTS

Based on the results, we found a direct and significant association between the levels of sound and the length of performance. Moreover, the participant's performance was significantly different for different sound levels (at 110 dB as opposed to 70 and 90 dB, p < 0.05 and p < 0.001, respectively).

CONCLUSION

This study found that a sound level of 110 dB had an important effect on the individuals' performances, i.e., the performances were decreased.

Influence of Sleep on Quality of Life Among Hospital Nurses

Introduction

Sleep disorders are the cause of morbidity and mortality and can decrease functional capacity and quality of life. Nurses, especially those working irregular or night shifts, are at risk for developing sleep disorders. The present study aims to determine the relationship between sleep quality and health-related quality of life (HRQOL) as well as quantitative and subjective aspects of sleep quality in nurses.

Methods

This cross-sectional study was conducted on 1456 nurses working in 11 hospitals in Shiraz and Tehran (Iran) in 2014. Structured questionnaires (Pittsburg Sleep Quality Index [PSQI] and Medical Outcomes Study Short Form-36 Survey [SF-36]) were used to collect data on participants’ demographic characteristics, sleep quality, and health-related quality of life. Chi-square and independent samples t-test were employed for statistical analysis.

Results

Mean age of participants was 30.81 ± 7.8, and most of them were female (89.04%) and poor sleepers. Long-duration sleepers slept for more than 9.8 h/night, and they obtained higher scores than short-duration sleepers (<4.5 h/night) in all SF-36 domains. The study results showed that increased quality of life was significantly related to health-related quality of life.

Conclusions

This study showed strong evidence that sleep disorders, such as poor quality and short duration of sleep, are negatively associated with HRQOL. Therefore, developing systemic strategies to cope with the problem seems to be necessary.

Assessment of Health Consequences of Steel Industry Welders' Occupational Exposure to Ultraviolet Radiation

BACKGROUND

Welding is among the most important frequently used processes in the industry with a wide range of applications from the food industry to aerospace and from precision tools to shipbuilding. The aim of this study was to assess the level of steel industry welders' exposure to ultraviolet (UV) radiation and to investigate the health impacts of these exposures.

METHODS

In this case-control study, we measured the intensity of UV at the workers' wrist in Fars Steel Company through manufacture of different types of heavy metal structures, using UV-meter model 666230 made by Leybold Co., from Germany.

RESULTS

The population under the study comprised 400 people including 200 welders as the exposed group and 200 nonwelders as the unexposed group. The results of the questionnaire were analyzed using SPSS software, version 19. The average, standard deviation, maximum and minimum of the UV at the welders' wrist were 0.362, 0.346, 1.27, and 0.01 μW/cm(2), respectively. There was a significantly (P < 0.01) higher incidence of cataracts, keratoconjunctivitis, dermatitis and erythema in welders than in their nonwelders.

CONCLUSIONS

This study showed that the time period of UV exposure in welders is higher than the permissible contact threshold level. Therefore, considering the outbreak of the eye and skin disorders in the welders, decreasing exposure time, reducing UV radiation level, and using personal protective equipment seem indispensable. As exposure to UV radiation can be linked to different types of skin cancer, skin aging, and cataract, welders should be advised to decrease their occupational exposures.

Investigation of the relationship between carrying school bags (handbags and backpacks) and the prevalence of musculoskeletal pains among 12-15 year old students in Shiraz

Inappropriate school bags put students at risk of musculoskeletal problems and early fatigue. Heavy bags can change the body posture and the musculoskeletal system must react appropriately in order to compensate for this stress. It is recommended that the weight of a school bag must not be more than 10% of the student's body weight and the weight must be placed on both shoulders. The present study aimed to identify the risk factors associated with musculoskeletal disorders by comparing the prevalence of musculoskeletal pains among the students. The present descriptive, cross-sectional study was conducted in different educational districts of Shiraz. The study samples were selected using cluster sampling method. In this study, 800 students marked their painful areas on body maps and the SPSS statistical software (v. 11.5) was used to analyze the data. The results showed that among the students who used backpacks, 48.9% carried the weight on both shoulders, 40.4% carried the weight on their right shoulders, and 10.6% used their left shoulders. Besides, 68.02% of the students carrying handbags often used their right shoulders, while 31.98% used their left shoulders. The study results showed that similar to other countries, Iranian students also mostly made use of backpacks. Moreover, the musculoskeletal pains were most prevalent in the shoulders, which is in line with many other studies conducted on the issue.

Short-term exposure with vibration and its effect on attention

BACKGROUND

About 20 to 50 percent of accidents are due to some forms of carelessness and mindedness. Studies suggested that vibration is one of the most important physical factors in human performance when traveling on any sort of vehicles. The aim of this study was to investigate the effect of vehicles vibration on cognitive performance (attention and concentration).

METHODS

The sample consists of 25 male students who undergone 4 experimental phases: acceleration low vibration (0.53 m/s(2)), medium vibration (0.81 m/s(2)), high vibration (1.12 m/s(2)) and non- exposure to vibration (control phase) according to ISO 2631-1 standard and with fixed frequency between 3 to 7 Hz. Students paired T test was applied to analysis the data, using SPSS software ver. 19.

RESULTS

The mean number of correct answers obtained from selective attention test under vibration levels of 0.53 m/s(2) and 0.81 m/s(2) were significantly lower than the condition without vibration. The mean reaction time of divided attention test in three vibration levels was significantly lower than the condition without vibration. Exposing to vibration reduces number of correct answers, selective attention and reaction time.

CONCLUSION

In this study, it was found that vibration may disrupt the ability of the participants for sustainability attention. It also changes the precision and speed of humans' information processing systems.

Oxidative Stress and Depression among Male Shift Workers in Shahid Tondgouyan Refinery

OBJECTIVE

The aim of this study was to determine the oxidative stress; serum level of Total Antioxidant Capacity (TAC)and Malondialdehyde (MDA) level and the depression score among the depressed rotational shift workers in Shahid Tondgouyan Refinery in Tehran (Iran).

METHODS

A cross-sectional study was conducted among all the 189 shift workers in Shahid Tondgouyan oil refinery who were eligible to participate in the study. They did not take any antidepressants for two months or any supplements for two weeks prior to the study entry. Written consent was obtained from the participants. 21- Item Beck Depression Inventory was used to measure the depression level. Furthermore, body weight, height and systolic and diastolic blood pressure were collected from all the participants. The levels of Total Antioxidant Capacity (TAC) and Malondialdehyde (MDA) were measured by 8 ml fasting blood sample. MDA was determined by thiobarbituric acid reaction. Serum total antioxidants were measured using the spectrophotometric ABTS. In the ABTS test, 2,2'-azinobis (3-ethylbenzthiazoline-6-acid) (ABTS) is converted into its radical cation (ABTS•+) by addition of sodium persulphate. This blue-green radical cation absorbs light at 734 nm. ABTS•+ is reactive towards most antioxidants. Descriptive statistics, ANOVA, ANCOVA and regression tests and correlation were used to analyze the data using SPSS software version 16.

RESULTS

The age of the participants ranged from 21 to 52 years. The mean age of the participants was 30.58 year (±6.97yr). Of all the participants, 28% (n= 53) had no depression symptoms (depression score between 0 and 9), 65.1% (n=123) were categorized as having mild depression (depression score between 10 and 18) and 6.9% (n=13) were categorized as having moderate depression (depression score between 19 and 29). The participants' BMI ranged from 15.9 to 34.3; the mean BMI of the participants was 24.82 kg/m(2) (+ 3.81 kg/m(2)). The mean of the serum TAC level was 2.51 (± 0.56) mg/dl, and the mean serum MDA level was 3.67(± 1.08) μmol/l. There was a significant difference in the mean TAC concentration between the non-depressed group and the group with mild depression (p=0.029).

CONCLUSION

Depression was associated with reduced mean TAC concentration and an increase in MDA level. There was a linear relationship between the depression score and shift work experience among the rotational shift workers, which showed a high level of stress and depression among the shift-workers.

Outline of changes in cortisol and melatonin circadian rhythms in the security guards of shiraz university of medical sciences

BACKGROUND

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

METHODS

The present study was conducted on 20 security guards of Shiraz University of Medical Sciences. In order to collect the study data, blood samples were taken from the study subjects in different times of the day (1, 4, 7, 10, 13, 16, 19, and 22) and cortisol and melatonin levels were determined using the radioimmunoassay and enzyme immunoassay techniques, respectively.

RESULTS

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

CONCLUSIONS

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

Biodegradation of alachlor in liquid and soil cultures under variable carbon and nitrogen sources by bacterial consortium isolated from corn field soil

Alachlor, an aniline herbicide widely used in corn production, is frequently detected in water resources. The main objectives of this research were focused on isolating bacterial consortium capable of alachlor biodegradation, assessing the effects of carbon and nitrogen sources on alachlor biodegradation and evaluating the feasibility of using bacterial consortium in soil culture. Kavar corn field soil with a long history of alachlor application in Fars province of Iran has been explored for their potential of alachlor biodegradation. The influence of different carbon compounds (glucose, sodium citrate, sucrose, starch and the combination of these compounds), the effect of nitrogen sources (ammonium nitrate and urea) and different pH (5.5-8.5) on alachlor removal efficiency by the bacterial consortium in liquid culture were investigated. After a multi-step enrichment program 100 days of acclimation, a culture with the high capability of alachlor degradation was obtained (63%). Glucose and sodium citrate had the highest alachlor reduction rate (85%). Alachlor reduction rate increased more rapidly by the addition of ammonium nitrate (94%) compare to urea. Based on the data obtained in the present study, pH of 7.5 is optimal for alachlor biodegradation. After 30 days of incubation, the percent of alachlor reduction were significantly enhanced in the inoculated soils (74%) as compared to uninoculated control soils (17.67%) at the soil moisture content of 25%. In conclusion, bioaugmentation of soil with bacterial consortium may enhance the rate of alachlor degradation in a polluted soil.

Effects of electromagnetic fields on mental health of the staff employed in gas power plants, Shiraz, 2009

The aims of this study are to assess, in a power station in Shiraz, the effects of noise and electromagnetic field on psychological mood. By the great industrial and technological improvements human beings have been exposed to different types of physical and chemical factors. Some of these factors such as electromagnetism are known as the constant components of the environment. According to the studies carried out in one of the power stations in Shiraz, psychological disorders caused by jobs are among the most important problems of the workers. This study is performed to determine the presence or absence of these psychological disorders. This cross-sectional study is performed on these groups : (1) The gas power plant staff who were in contact with electromagnetic field and nose, (2) employees who were only exposed to noise and (3) a group of staff employed in the administrative parts of the Telecommunication companies who did not have any history of being exposed to electromagnetic field and sounds. The General Health Questionnaire (GHQ) is used in this study to recognize psychosomatic disorders. Measurements indicate that range of electromagnetic field varies from 0.087 micro Tesla in the phone homes to 30 micro Tesla in power stations. The results of this study has shown that a significant number of staff which were exposed to electromagnetic fields and noise (78.2%) were suspected to have a kind of mental disorders. The results obtained from this study which shows the prevalence of mental disorders among the suspected case is higher than the results of Noorbala and colleagues study in 2006.

Effect of bright light on shift work nurses in hospitals

The aim of this study are to assess, in a hospital setting, the effects of Bright Light (BL) on the rhythms in body temperature, plasma melatonin, plasma cortisol and subjective alertness during shift work. In our experimental design, 34 healthy shift work nurses from a university hospital were exposed to bright light (4500 lux) during two break times (21:15 to 22; 00 and 3:15 to 4:00) for four consecutive weeks. In this survey, the subjects were studied under 24 h of realistic conditions during which their plasma cortisol and plasma melatonin was measured at 3 h intervals. In addition, their body temperatures were measured during and after night shift work. Subjective alertness and fatigue were evaluated with the Karolinska Sleepiness Scale (KSS) and Visual Analog Scale (VOI). It was found that bright light administration significantly suppressed nighttime melatonin levels during night shift, most strongly at 2:00 a.m. A one-way ANOVA, with repeated measurement design, revealed that Bright Light (BL) tended to increase cortisol levels and body temperature and improved alertness significantly during night shift. These results demonstrate that photic stimulation in a hospital setting can have a powerful influence on the adjustment of the circadian system.

The efficiency of Amberjet 4200 resin in removing nitrate in the presence of competitive anions from Shiraz drinking water

The aim of this research is to study the feasibility of removing nitrates from water by means of anion exchange. In the purposed work an attempt was made to utilize strong basic anion resin to remove nitrate in the presence of competitive anion. Amberjet Cl- 4200 ion exchange resin was used in a batch scale. The fixation rate of nitrate without the presences of any competitive anion was almost constant (94.60-96.43) when the nitrate concentrations are in the range of 100-150 mg L(-1). The fixation rate of nitrate in the presences of two competitive anions (sulphate and chloride) was reduced to 82% when the concentration of nitrate was 100 mg L(-1).

Assessment of atrazine distribution in Shiraz soils, south of Iran

The main objective of this study was focused on determining atrazine residual concentration in agricultural soil in Shiraz and its vicinity. Twenty two sampling fields were selected by grid sampling in Shiraz and its vicinity. Atrazine residual concentrations in 0-20, 20-40 and 40-60 cm soil depths were in the range of 15-550 microg kg(-1) soil. Data showed that the concentration of atrazine did not exceed the soil quality standard for agriculture which is 22 mg kg(-1) soil and there was no significant difference between depth and atrazine residual concentration (p > 0.05). Although, in all sampling regions in Shiraz and its vicinity, the concentration of atrazine did not exceed the soil quality standard for agriculture, atrazine leaching and dissipation rate in soil and risk of atrazine ground water pollution must be determined.

Assessment of the potential of scale formation and corrosivity of tap water resources and the network distribution system in Shiraz, South Iran

The aim of this research is to study the potential of scale formation and corrosivity of water resources and the network distribution system of Shiraz in Fars province, South Iran. The Langelier saturation index (LSI) was used to assess the scale formation and corrosivity. The index was calculated based on the principle of calcium deposition. This research was done through 118 water resources samples which include wells and surface water and many different points in the network distribution system during late Summer and early fall, 2007. The mean LSI value for all the samples was 0.417. Although, the results indicated the scaling potential in all water samples, monitoring the corrosion rates was done on a regular basis. Seasonal changes can affect water quality, and therefore the corrosion rates.