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.

Job stress and resilience in Iranian nurses during the COVID-19 pandemic: A case-control study.

BACKGROUND: The COVID-19 pandemic has created a wide range of sociocultural pressures on nurses. Resilience is defined as one's ability to adapt to an unpredictable situation and it can be a factor in accepting an undesirable psychosocial situation. OBJECTIVE: The aim of the present study was to examine resilience in nurses in the face of job stress during the COVID-19 pandemic. METHODS: The study was carried out as a case-control study with participation of 400 nurses as the target group (nurses exposed to COVID-19 patients) and the control group (nurses not exposed to COVID-19 patients). To examine resilience and job stress, Conor and Davidson's questionnaire and OSIPOW questionnaire were used respectively. RESULTS: The mean scores of job stress and resilience were significantly different between the target and control groups (p < 0.05). So that resilience in the target group was less than that in the control group. In addition, job stress in the target group was higher than that of the control group (p < 0.05). There was a significant and negative correlation between resilience and job stress and the correlation was stronger in the target group (p < 0.05). CONCLUSIONS: Given the high job stress score in the participants and its negative correlation with resilience, there is need to provide the health personnel with efficient preventive and treatment approaches, improve and educate the principles of resilience, improve mental health services system, and introduce programs to control some of demographical factors in job stress such as physical activity, and employment status of nurses.

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.

Assessing Reliability and Validity of an Instrument for Measuring Resilience Safety Culture in Sociotechnical Systems.

BACKGROUND: Safety culture, acting as the oil necessary in an efficient safety management system, has its own weaknesses in the current conceptualization and utilization in practice. As a new approach, resilience safety culture (RSC) has been proposed to reduce these weaknesses and improve safety culture; however, it requires a valid and reliable instrument to be measured. This study aimed at evaluating the reliability and validity of such an instrument in measuring the RSC in sociotechnical systems. METHODS: The researchers designed an instrument based on resilience engineering principles and safety culture as the first instrument to measure the RSC. The RSC instrument was distributed among 354 staff members from 12 units of an anonymous petrochemical plant through hand delivery. Content validity, confirmatory, and exploratory factor analysis were used to examine the construct validity, and Cronbach alpha and test-retest were employed to examine the reliability of the instrument. RESULTS: The results of the content validity index and content validity ratio were calculated as 0.97 and 0.83, respectively. The explanatory factor analysis showed 14 factors with 68.29% total variance and 0.88 Kaiser-Meyer-Olkin index. The results were also confirmed with confirmatory factor analysis (relative Chi-square = 2453.49, Root Mean Square Error of Approximation = 0.04). The reliability of the RSC instrument, as measured by internal consistency, was found to be satisfactory (Cronbach α = 0.94). The results of test-retest reliability was r = 0.85, p < 0.001. CONCLUSION: The results of the study suggest that the measure shows acceptable validity and reliability.

Cancer Risk Assessment in Welder's Under Different Exposure Scenarios.

BACKGROUND: Welders exposure to nickel and hexavalent chromium in welding fumes is associated with increase of cancer risk in welders. In this study we calculated cancer risk due to exposure to these compounds in welders. METHODS: The role of exposure parameters in welders on derived incremental lifetime cancer risk were determined by stochastic modeling of cancer risk. Input parameters were determined by field investigation in Iranian welders in 2013 and literature review. RESULTS: The 90% upper band cancer risk due to hexavalent chromium and nickel exposure was in the range of 6.03E-03 to 2.12E-02 and 7.18E-03 to 2.61E-02 respectively. Scenario analysis showed that asthmatic and project welders are significantly at higher cancer risk in comparison with other welders (P<0.05). Shift duration was responsible for 37% and 33% of variances for hexavalent chromium and nickel respectively. CONCLUSIONS: Welders are at high and unacceptable risk of cancer. Control measures according to scenario analysis findings are advisable.