Interaction between physical, psychosocial, and organisational work factors for low back symptoms and its consequences amongst Indonesian coal mining workers

Although there is strong evidence that single physical, psychosocial and organisational risk factors are each independent predictors of low back symptoms (LBS) and its consequences, little is known about their combination/ interaction. A preliminary study was conducted among 673 workers as part of a larger study (n=1294) in a coal mining company in Indonesia. A self-reported questionnaire was used to obtain physical and psychosocial exposures, and organisational factors. Each participant was grouped into one of four combination exposure groups: 1) high physical (working with bent trunk, whole body vibration exposure, lifting) and high psychosocial (high effort, low reward, work stress), 2) high physical and low psychosocial, 3) low physical and high psychosocial, 4) low physical and low psychosocial (as the reference group). Individuals in the high physical and high psychosocial group were the most likely to report LBS (OR 3.47 95% CI 1.81-6.64), reduced activities (OR 6.94 95% CI 1.58-30.49) and absenteeism (OR 7.01 95% CI 2.04-24.10). Permanent workers were more likely to report LBS and its consequences whereas night shift work increased the risk of LBS consequences. Interventions to reduce LBS and its consequences should address both physical and psychosocial factors, with a focus on permanent and night shift workers.