The effect of physical and psychosocial occupational factors on the chronicity of low back pain in the workers of Iranian metal industry: a cohort study.

Background: Low back pain (LBP) is one of the most common problems among the workers of different industries. The role of occupational factors in causing the LBP has been indicated previously. LBP has great socio-economic costs and most of its costs are related to the chronic LBP.