Objective: To evaluate relationships between lifting and lowering of loads and risk of low back pain resulting in medication use (M-LBP).
Methods: At baseline, worker demographics, psychosocial factors, hobbies, LBP history, and lifting and lowering (quantified using the Revised NIOSH Lifting Equation) were assessed. A cohort of 258 incident-eligible workers was followed up for 4.5 years to determine new M-LBP cases and changes in lifting/lowering requirements. Proportional hazards regression with time-varying covariates was used to model associations.
Results: Factors predicting M-LBP included peak lifting index (PLI) and composite lifting index (PCLI), LBP history, anxiety, and housework. In adjusted models, PLI and PCLI showed exposure-response relationships with peak hazard ratios of 3.8 and 4.3, respectively (P ≤ 0.02).
Conclusions: Lifting of loads is associated with increased risk of M-LBP. The PLI and PCLI are useful metrics for estimating the risk of M-LBP from lifting.