| Low back pain (LBP) afflicts a vast majority of the working population in the United States with enormous human and economic costs. The risk factors for future LBP in individuals with past LBP remain unclear. This research was undertaken to study the relationship between quantified job physical demands and future occupational LBP (OLBP) in industrial workers with a history of LBP, while adjusting for significant covariates. One hundred and thirty industrial workers with past LBP (but pain free for at least 90 days at baseline) were studied prospectively for 4.5 years. Baseline job, individual and psychosocial data were collected. Workers were followed to observe changes in LBP status and job physical demands. LBP outcomes studied included OLBP lasting at least one day (OLBP-A), OLBP-A with medication use (OLBP-M), OLBP-A resulting in healthcare provider visit (OLBP-H) and OLBP-A resulting in lost workdays or light/restricted duty (OLBP-L). Quantified job physical demands for each worker included Lifting Index, back compressive force, strength requirement (minimum percent population capable) and load moment. Covariates studied included baseline individual and psychosocial factors.;In multivariate analyses, Lifting Index and load moment showed evidence of association (p≤0.05) with OLBP-A while accounting for combined past history of LBP (CPLBP), feelings of tension, edginess and nervousness (TEN), weightlifting and job satisfaction. There was evidence of association (p≤0.05) of peak Composite Lifting Index with OLBP-M while accounting for CPLBP, feelings of TEN, body mass index and job satisfaction. There was marginal evidence of association (0.05<p≤0.10) of minimum percent population capable and OLBP-H while accounting for CPLBP and high cholesterol. There was evidence of strong association of minimum percent population capable with OLBP-L while accounting for walking and weightlifting.;It is concluded that quantified job physical demands are associated with OLBP while accounting for significant individual and psychosocial factors. Lifting Index and load moment are predictive of least conservative outcomes (OLBP-A and OLBP-M) while minimum percent population capable is predictive of more conservative outcomes (OLBP-H and OLBP-L). Combined past history of LBP is a risk factor for OLBP outcomes. |
