Prolonged sitting at work is associated with a favorable time course of low-back pain among blue-collar workers: a prospective study in the DPhacto cohort.

Objective Low-back pain (LBP) is a massive health problem. Sitting at work has been suggested to be both a risk and protective factor for LBP. Thus, the objective of this study was to investigate the association between total and temporal patterns of objectively measured sitting duration and individual time course of LBP. Methods The analysis was performed among 665 participants from the DPhacto cohort of mainly blue-collar workers. Sitting at work was measured by accelerometry at baseline, expressed in total duration and temporal pattern [% of working time spent in brief bursts (≤5 minutes), moderate (>5 - ≤20 minutes) and prolonged periods (>20 minutes)] of sitting. Time course of LBP (0-10 scale) were collected by monthly text messages across one year. Linear mixed models were applied to investigate the association, adjusting for potential confounders. Results Significant negative associations between sitting duration at work and adjusted time course of LBP were found; total sitting (B -0.01, 95% CI -0.01- -0.004), brief bursts (B -0.01, 95% CI -0.02- -0.01), moderate (B -0.01, 95% CI -0.01- -0.008) and prolonged periods (B -0.01, 95% CI -0.02- -0.01). Meaning, a 5-minute increase of sitting at work will correspond to a decrease in one year time course of LBP by -0.05 points. Conclusion Longer duration of total and temporal sitting periods at work was significantly associated with a favorable time course of LBP. This finding shows sitting at work to be beneficial for LBP, among populations of mainly blue-collar workers, by protecting from LBP aggravation.