Development and validation of an environmental heat strain risk assessment (EHSRA) index using structural equation model
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(2020) 25:63
Environmental Health and Preventive Medicine
RESEARCH ARTICLE
Open Access
Development and validation of an environmental heat strain risk assessment (EHSRA) index using structural equation modeling based on empirical relations Saeid Yazdanirad1 , Farideh Golbabaei1* , Abbas Rahimi Foroushani2, Mohammad Reza Monazzam1 and Habibollah Dehghan3
Abstract Background: Need to a simple, available, accurate, comprehensive, and valid indicator is felt to assess thermal effects. Therefore, the present study was aimed to develop and validate the environmental heat strain risk assessment (EHSRA) index using structural equation modeling (SEM) based on empirical relations. Methods: This cross-sectional study was performed on 201 male workers in environments with various climatic conditions. The heart rate and tympanic temperature of the individuals were monitored at times of 30, 60, and 90 min after beginning the work. At these times, values of dry temperature, wet temperature, globe temperature, and air velocity were also measured and metabolism rate and clothing thermal insulation value were estimated. At the end, a theoretical model was depicted in AMOS software and obtained coefficients were applied to develop a novel index. The scores of this indicator were categorized into four risk levels via ROC curves and validate using linear regression analysis. Results: Indirect effect coefficients of the globe temperature, dry temperature, wet temperature, air velocity, metabolism, and clothing thermal insulation variables on the tympanic temperature were computed by 0.77, 0.75, 0.69, 0.24, 0.49, and 0.39, respectively. These coefficients were applied to develop the index. Optimal cut-off points of boundaries between risk levels included 12.02, 15.88, and 17.56. The results showed that the EHSRA index justified 75% of the variations of the tympanic temperature (R2 = 0.75). Conclusions: The novel index possesses appropriate validity. It was suggested that this indicator is applied and validated in various environments in the next studies. Keywords: Heat stress, Risk assessment, Structural equation modeling, Empirical index
Background People occupied in industrial environments are exposed to many hazards to threaten their health. Heat is one of the most prominent physical harmful agents in workplaces. Nearly 40% of the world’s people live in the warm and hot * Correspondence: [email protected] 1 Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Full list of author information is available at the end of the article
climatic regions of the earth, where normal daytime temperatures are higher than 30 °C at most days of a year [1]. In these zones, numerous workers are performing routine tasks. Global warming will increase adverse thermal effects on bodily health [2]. The results of several studies show that air temperature may raise from 1.1 to 6.4 °C at the end of the twenty-first century compared to the nineteenth century [3]. Additionally, p
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