Is prolonged sitting at work associated with the time course of neck–shoulder pain? A prospective study in Danish blue-collar workers

OBJECTIVES: This study aimed to determine the extent to which objectively measured sitting time at work is associated with the course of neck–shoulder pain across 1 year in blue-collar workers. METHODS: Data were analysed from 625 blue-collar workers in the Danish PHysical ACTivity cohort with Objective measurements (DPHACTO) cohort study (2012–2013). Objective data on sitting time were collected at baseline using accelerometry. Self-reported pain intensity (numeric rating scale 0–10) in the neck–shoulder region was registered for 1 year using repeated text messages (14 in total). Linear mixed models were used to determine the relationship between per cent time in sitting at work and trajectories of neck–shoulder pain, with and without adjustment for demographic, occupational and lifestyle factors, and baseline pain intensity. RESULTS: More sitting time at work was associated with a faster decline in pain intensity over 12 months, as indicated by a statistically significant effect of sitting on pain trajectories in the crude (p=0.020) and fully adjusted models (p=0.027). CONCLUSIONS: In blue-collar workers, more sitting time at work was associated with a favourable development of pain intensity over time. The relationship between sitting at work and pain needs further investigation before explicit recommendations and guidelines on sedentary behaviour among blue-collar workers can be developed.