Associations of objectively measured forward bending at work with low-back pain intensity: a 2-year follow-up of construction and healthcare workers

Abstract

OBJECTIVES: This study aimed to determine possible associations between objectively measured forward bending at work (FBW) and low-back pain intensity (LBPi) among Norwegian construction and healthcare workers. METHODS: One-hundred and twenty-five workers wore two accelerometers for 3-4 consecutive days, during work and leisure to establish duration of ≥30° and ≥60° forward bending. The participating workers reported LBPi (0-3) at the time of objective measurements and after 6, 12, 18 and 24 months. We investigated associations using linear mixed models with significance level p≤0.05 and presented results per 100 min. RESULTS: The duration of ≥30° and ≥60° FBW was not associated with average LBPi during follow-up, neither for the total sample nor stratified on work sector. Furthermore, analyses on all workers and on construction workers only found no significant association between ≥30° or ≥60° FBW and change in LBPi over the 2-year follow-up. For healthcare workers we found a consistent significant association between the duration of ≥30° FBW at baseline and the change in LBPi during follow-up, but this was not found for ≥60° FBW. CONCLUSIONS: This study suggests that objectively measured duration of FBW in minutes is not associated with average levels of, or change in LBPi in construction workers over a 2-year period. In healthcare workers, exposure to ≥30° FBW was associated with change in LBPi, while we did not find this for ≥60° FBW. Results may indicate that the associations between FWB and LBP vary depending on type of work tasks, gender or sector-specific factors.