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. The aim of this study was to identify the occupational risk factors that are related to the progression of the LBP from acute to chronic phase. Methods: This cohort study has been conducted on 185 workers with acute LBP. Information related to their occupational exposure at baseline has been measured with a valid questionnaire using the self-report approach. Patients follow up was done monthly for three months after the start of the pain. Those workers whose occupational exposure had not changed during the follow up were divided into two groups of chronic LBP (n = 49) and cured (n = 136) according to the duration of the pain period (more or less than 3 months), and their job exposures were compared. Results: Among the physical and psychosocial risk factors, social support (OR= 0.466, CI= 0.231- 0.940) and job satisfaction (OR= 0.455, CI= 0.232-0.891), and lifting weights more than 15kg (OR=2.482, CI= 1.274-4.834) indicated a significant relationship with the chronicity of the LBP. After putting the variables into the regression model, only lifting>15kg remained statistically significant. Conclusion: According to the observed relationship between these occupational risk factors (social support, job satisfaction, lifting>15kg) and the chronicity of the LBP, there is hope that eliminating these factors in the workers with acute LBP will prevent its progression to the chronic phase.