title: Neck pain and postural balance among workers with high postural demands - a cross-sectional study.
abstract: BACKGROUND
  Neck pain is related to impaired postural balance among patients and is highly prevalent among workers with high postural demands, for example, cleaners. We therefore hypothesised, that cleaners with neck pain suffer from postural dysfunction. This cross-sectional study tested if cleaners with neck pain have an impaired postural balance compared with cleaners without neck pain.
  
  
  METHODS
  Postural balance of 194 cleaners with (n = 85) and without (N = 109) neck pain was studied using three different tests. Success or failure to maintain the standing position for 30 s in unilateral stance was recorded. Participants were asked to stand on a force platform for 30 s in the Romberg position with eyes open and closed. The centre of pressure of the sway was calculated, and separated into a slow (rambling) and fast (trembling) component. Subsequently, the 95% confidence ellipse area (CEA) was calculated. Furthermore a perturbation test was performed.
  
  
  RESULTS
  More cleaners with neck pain (81%) failed the unilateral stance compared with cleaners without neck pain (61%) (p < 0.01). However, the risk of failure in unilateral stance was statistically elevated in cleaners with concurrent neck/low back pain compared to cleaners without neck/low back pain (p < 0.01), whereas pain at only neck or only low back did not increase the risk. Impaired postural balance, measured as CEA (p < 0.01), rambling (p < 0.05) and trembling (p < 0.05) was observed among cleaners with neck pain in comparison with cleaners without neck pain in the Romberg position with eyes closed, but not with eyes open.
  
  
  CONCLUSIONS
  Postural balance is impaired among cleaners with neck pain and the current study suggests a particular role of the slow component of postural sway. Furthermore, the unilateral stance test is a simple test to illustrate functional impairment among cleaners with concurrent neck and low back pain.
  
  
  BACKGROUND
  ISRCTN96241850.
authors.affiliation: National Research Centre for the Working Environment, Copenhagen, Denmark. mbj@nrcwe.dk
authors.forename: Marie B
authors.initials: MB
authors.lastname: Jørgensen
authors.forename: Jørgen H
authors.initials: JH
authors.lastname: Skotte
authors.forename: Andreas
authors.initials: A
authors.lastname: Holtermann
authors.forename: Gisela
authors.initials: G
authors.lastname: Sjøgaard
authors.forename: Nicolas C
authors.initials: NC
authors.lastname: Petersen
authors.forename: Karen
authors.initials: K
authors.lastname: Søgaard
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D009784:Occupational Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D009790:Occupations; D016017:Odds Ratio; D010147:Pain Measurement; D004856:Postural Balance; D011187:Posture; D018570:Risk Assessment; D012307:Risk Factors; D012678:Sensation Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D011795:Surveys and Questionnaires; D055815:Young Adult