Development of lower back pain prevention index due to whole body vibration: system dynamics

Abstract

Prolonged exposure to whole body vibration (WBV) is a major health hazard for construction workers, leading to various chronic health problems. Heavy equipment operators (HEOs) are exposed to WBV most of the time. This causes both short and long-term health effects, such as headache, motion sickness, spinal disc disease, and lower back pain (LBP). LBP due to WBV exposure causes high compensation cost, and a long–term LBP prevention program is needed to reduce the compensation cost. To develop an effective program to reduce LBP due to WBV exposure in the long-term, however, there are a number of influential factors to consider, for example, working hour, age of the worker, age of the machine, job satisfaction, and working experience. These factors also have influence on each other, making it hard to plan for long-term implementation. This study, thus, develops a dynamic model of LBP prevention index to reduce LBP due to WBV exposure in the construction industry in the long-term. Five key factors affecting due to WBV exposure are hypothesized, together with 17 associated items, based on a number of construction and health related literatures. A questionnaire survey is then developed; based on the 17 items, for data collection in Sri Lankan construction industry. The collected data are screened and performed with the exploratory factor analysis to confirm five key factors affecting LBP due to WBV exposure with their associated items. The organizational and equipment factors are extracted with four associated items each, while the personal, job related, and social context factors are associated with three items each. Five key factors are performed with the structural equation modelling to examine causal relationships among those factors. The results reveal that the organizational factor plays a primary role in improving LBP prevention program, as it influences the other four factors directly and indirectly, while equipment factor is affected by the other four factors. It is then suggested that providing new machines are not effective in reducing LBP symptoms without proper training and good working conditions. The dynamic model of the LBP prevention index is then developed based on the five key factors, and their inter relationships utilizing a system dynamics modelling technique. The LBP prevention index developed, in the model is used to assess a current level of LBP prevention maturity. The developed dynamic model is simulated, and the results show that with proper LBP prevention program, the construction company achieves a higher LBP prevention index through time. The results show that the construction company is currently in level 2 of maturity. With supports from management, the company reaches level 3 in year 4 and level 4 in eight years. To achieve level 5, however, it takes both effort and support, mainly on budget, to proceed with program implementation. With continuous improvement, the company can reach level 5 of maturity at the end of year 39. The results also show the importance of workers over equipment provision to achieve higher maturity levels. The company, therefore, should focus on providing adequate budget to support the LBP-related activities, such as LBP related training, job rotation, and exercise scheme to reduce chances of having LBP. The construction company can perform alternative strategies to effectively plan for LBP prevention maturity. Strategies, such as hiring workers, training workers, purchasing new equipment, and mixed strategies are tested to achieve higher LBP prevention index in the long-term. The dynamic model of LBP prevention index brings insights into five key factors, affecting LBP due to WBV exposure, as well as their inter relationships. A construction company can use the developed dynamic model to effectively plan for LBP prevention program to achieve higher maturity level in the long-term. This proves the contribution of the study to the world-wide construction industry.