The aim of this study was to evaluate relationships between job physical demands and risk of low-back pain (LBP), using medication to treat LBP (M-LBP) and seeking care for LBP (SC-LBP).Methods
Worker demographics, LBP history, psychosocial factors, hobbies, job physical demands (using the Revised NIOSH Lifting Equation) were assessed at the time of enrollment (551 workers). There were 258 incident-eligible workers (a continuous pain-free period of at least 90 days at the time of enrollment) and were followed monthly for up to 4.5 years to determine new LBP, M-LBP, and SC-LBP cases. Changes in job physical demands were measured. Associations between risk factors and LBP outcomes were modelled using proportional hazards regression with time varying covariates.Results
LBP and M-LBP were fairly common affecting 47.7% and 37% workers, respectively. SC-LBP much less common affecting 1 in 11 workers. Peak Lifting Index (PLI) and Peak Composite Lifting Index (PCLI) were associated with all three outcomes of LBP (p<0.05). PLI and PCLI had peak Hazard Ratios of 4.3 and 4.2 for LBP, 3.8 and 4.3 for M-LBP, and 23.0 and 21.9 for SC-LBP, respectively. LBP history was associated with all three outcomes of LBP. Age, gender, BMI, hobbies, and psychosocial factors showed inconsistent relationships with the three outcomes of LBP.Conclusion
Job physical demands are associated with increased risk of LBP, M-LBP and SC-LBP. The PLI and PCLI are useful metrics for estimating job physical demands.