title: A randomised controlled trial evaluating the effects of two workstation interventions on upper body pain and incident musculoskeletal disorders among computer operators.
abstract: BACKGROUND
  Call centre work with computers is associated with increased rates of upper body pain and musculoskeletal disorders.
  
  
  METHODS
  This one year, randomised controlled intervention trial evaluated the effects of a wide forearm support surface and a trackball on upper body pain severity and incident musculoskeletal disorders among 182 call centre operators at a large healthcare company. Participants were randomised to receive (1) ergonomics training only, (2) training plus a trackball, (3) training plus a forearm support, or (4) training plus a trackball and forearm support. Outcome measures were weekly pain severity scores and diagnosis of incident musculoskeletal disorder in the upper extremities or the neck/shoulder region based on physical examination performed by a physician blinded to intervention. Analyses using Cox proportional hazard models and linear regression models adjusted for demographic factors, baseline pain levels, and psychosocial job factors.
  
  
  RESULTS
  Post-intervention, 63 participants were diagnosed with one or more incident musculoskeletal disorders. Hazard rate ratios showed a protective effect of the armboard for neck/shoulder disorders (HR = 0.49, 95% CI 0.24 to 0.97) after adjusting for baseline pain levels and demographic and psychosocial factors. The armboard also significantly reduced neck/shoulder pain (p = 0.01) and right upper extremity pain (p = 0.002) in comparison to the control group. A return-on-investment model predicted a full return of armboard and installation costs within 10.6 months.
  
  
  CONCLUSIONS
  Providing a large forearm support combined with ergonomic training is an effective intervention to prevent upper body musculoskeletal disorders and reduce upper body pain associated with computer work among call centre employees.
authors.affiliation: Division of Occupational and Environmental Medicine, Department of Medicine, University of California, San Francisco, CA 94804, USA. drempel@itsa.ucsf.edu
authors.forename: D M
authors.initials: DM
authors.lastname: Rempel
authors.forename: N
authors.initials: N
authors.lastname: Krause
authors.forename: R
authors.initials: R
authors.lastname: Goldberg
authors.forename: D
authors.initials: D
authors.lastname: Benner
authors.forename: M
authors.initials: M
authors.lastname: Hudes
authors.forename: G U
authors.initials: GU
authors.lastname: Goldner
mesh_terms: D000328:Adult; D016287:Computer Peripherals; D016288:Computer Terminals; D006804:Ergonomics / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005542:Forearm; D006801:Humans; D008297:Male; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000517:prevention & control*; D019547:Neck Pain / Q000517:prevention & control; D009784:Occupational Diseases / Q000517:prevention & control*; D016273:Occupational Exposure; D010146:Pain / Q000517:prevention & control*; D011482:Protective Devices; D020069:Shoulder Pain / Q000517:prevention & control