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

This study assessed the interaction between physical and psychosocial factors for low back symptoms (LBS) and its consequences (reduced activities and absenteeism) in a developing country. A sample of 1294 Indonesian coal mining workers reported occupational exposures, LBS and its consequences using a self-administered questionnaire. Respondents were placed into one of four combination exposure groups: high physical and high psychosocial (HPhyHPsy); high physical and low psychosocial (HPhyLPsy); low physical and high psychosocial (LPhyHPsy), and; low physical and low psychosocial (LPhyLPsy). The attributable proportion due to interaction between physical and psychosocial factors was examined. Individuals in the HPhyHPsy group were most likely to report LBS (OR 5.42, 95% CI 3.30-8.89), reduced activities (OR 4.89, 95% CI 3.09-7.74), and absenteeism (OR 4.96, 95% CI 3.05-8.06). Interactions between physical and psychosocial factors were present for LBS, reduced activities, and absenteeism; although for LBS and absenteeism the interactions were not significant. Current smokers were more likely to report LBS consequences. Permanent employment and night shift work increased the odds of LBS and its consequences. We conclude that interventions aimed at reducing LBS and its consequences should address both physical and psychosocial factors, with a focus on smokers, permanent employment and night shift work.