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

Abstract

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.