A cluster-randomized trial of workplace ergonomics and neck-specific exercise versus ergonomics and health promotion for office workers to manage neck pain – a secondary outcome analysis

BACKGROUND: Neck pain is prevalent among office workers. This study evaluated the impact of an ergonomic and exercise training (EET) intervention and an ergonomic and health promotion (EHP) intervention on neck pain intensity among the All Workers and a subgroup of Neck Pain cases at baseline. METHODS: A 12-month cluster-randomized trial was conducted in 14 public and private organisations. Office workers aged ≥18 years working ≥30 h per week (n = 740) received an individualised workstation ergonomic intervention, followed by 1:1 allocation to the EET group (neck-specific exercise training), or the EHP group (health promotion) for 12 weeks. Neck pain intensity (scale: 0–9) was recorded at baseline, 12 weeks, and 12 months. Participants with data at these three time points were included for analysis (n = 367). Intervention group differences were analysed using generalized estimating equation models on an intention-to-treat basis and adjusted for potential confounders. Subgroup analysis was performed on neck cases reporting pain ≥3 at baseline (n = 96). RESULTS: The EET group demonstrated significantly greater reductions in neck pain intensity at 12 weeks compared to the EHP group for All Workers (EET: β = − 0.53 points 95% CI: − 0.84– − 0.22 [36%] and EHP: β = − 0.17 points 95% CI: − 0.47–0.13 [10.5%], p-value = 0.02) and the Neck Cases (EET: β = − 2.32 points 95% CI: − 3.09– − 1.56 [53%] and EHP: β = − 1.75 points 95% CI: − 2.35– − 1.16 [36%], p = 0.04). Reductions in pain intensity were not maintained at 12 months with no between-group differences observed in All Workers (EET: β = − 0.18, 95% CI: − 0.53–0.16 and EHP: β = − 0.14 points 95% CI: − 0.49–0.21, p = 0.53) or Neck Cases, although in both groups an overall reduction was found (EET: β = − 1.61 points 95% CI: − 2.36– − 0.89 and EHP: β = − 1.9 points 95% CI: − 2.59– − 1.20, p = 0.26). CONCLUSION: EET was more effective than EHP in reducing neck pain intensity in All Workers and Neck Cases immediately following the intervention period (12 weeks) but not at 12 months, with changes at 12 weeks reaching clinically meaningful thresholds for the Neck Cases. Findings suggest the need for continuation of exercise to maintain benefits in the longer term. CLINICAL TRIAL REGISTRATION: hACTRN12612001154897 Date of Registration: 31/10/2012. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12891-021-03945-y.