Association between lifting and use of medication for low back pain: results from the Backworks Prospective Cohort
Jay M Kapellusch1, Arun Garg, Sruthi Boda
1From the Departments of Occupational Science and Technology (Drs Kapellusch, Garg, and Tomich), and Industrial and Manufacturing Engineering (Dr Boda), University of Wisconsin-Milwaukee; Rocky Mountain Center for Occupational and Environmental Health (Drs Hegmann, Thiese, and Bloswick), University of Utah, Salt Lake City; School of Rural Public Health (Dr Moore), Texas A&M University, College Station; Department of Mechanical Engineering (Dr Merryweather), University of Utah, Salt Lake City; Infinity HealthCare (Dr Foster), Milwaukee, Wis; and Department of Mathematics and Statistics (Dr Malloy), American University, Washington, DC.
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.
