Investigating the Effects of Workload, Fatigue, Sleep Quality and Posture on Musculoskeletal Disorders in Workers in the Steel Industry

Musculoskeletal disorders (MSDs) are widespread and important health and social problems in industrialised society, reducing productivity, increasing treatment costs and affecting the quality of life of workers. The present study was conducted with the aim of investigating the effects of workload, fatigue, sleep quality and physical condition on musculoskeletal disorders among workers in the steel industry.

The present study is a descriptive and analytical study conducted on a population of 540 workers working in the steel industry in the city of Dezful. Based on simple random sampling, 400 people were selected as samples. The instruments used in this study are the Demographic Information Questionnaire, the Cornell Musculoskeletal Disorders Questionnaire (CMDQ), the Swedish Occupational Fatigue Inventory(SOFI), the Pittsburgh Sleep Quality (PSQI) and the NASA-TLX workload index. The Rapid Entire Body Assessment (REBA) was used. Descriptive statistical indices were used to analyze the data, and the relationships between observed and hidden variables were examined using structural equation modeling (SEM) The data were analyzed at a significance level of 0.05 and in SPSS software version 25.

According to the prevalence of musculoskeletal disorders, back pain ranked first with a mean and standard deviation of 52.39±25.44 and knee pain ranked second with a mean and standard deviation of 46.46±26.45, indicating that the prevalence of these disorders is high among steel industry workers. The results of the correlation analysis showed that there is a positive and significant relationship between workload, fatigue, sleep quality and body condition and musculoskeletal disorders (p<0.05). The RMSEA index of less than 0.1 shows that the model proposed in this study fits well and demonstrates the role of workload variables, fatigue, sleep quality and body position in the direct and indirect causation of musculoskeletal disorders.

The results of this study show that improving workplace ergonomics, reducing workload and fatigue, and improving sleep quality can reduce the likelihood of musculoskeletal disorders in workers.