title: Meta-analysis: association between wrist posture and carpal tunnel syndrome among workers.
abstract: BACKGROUND
  Carpal tunnel syndrome (CTS) is a common work-related peripheral neuropathy. In addition to grip force and repetitive hand exertions, wrist posture (hyperextension and hyperflexion) may be a risk factor for CTS among workers. However, findings of studies evaluating the relationship between wrist posture and CTS are inconsistent. The purpose of this paper was to conduct a meta-analysis of existing studies to evaluate the evidence of the relationship between wrist posture at work and risk of CTS.
  
  
  METHODS
  PubMed and Google Scholar were searched to identify relevant studies published between 1980 and 2012. The following search terms were used: "work related", "carpal tunnel syndrome", "wrist posture", and "epidemiology". The studies defined wrist posture as the deviation of the wrist in extension or flexion from a neutral wrist posture. Relative risk (RR) of individual studies for postural risk was pooled to evaluate the overall risk of wrist posture on CTS.
  
  
  RESULTS
  Nine studies met the inclusion criteria. All were cross-sectional or case-control designs and relied on self-report or observer's estimates for wrist posture assessment. The pooled RR of work-related CTS increased with increasing hours of exposure to wrist deviation or extension/flexion [RR = 2.01; 95% confidence interval (CI): 1.646-2.43; p < 0.01: Shore-adjusted 95% CI: 1.32-2.97].
  
  
  CONCLUSIONS
  We found evidence that prolonged exposure to non-neutral wrist postures is associated with a twofold increased risk for CTS compared with low hours of exposure to non-neutral wrist postures. Workplace interventions to prevent CTS should incorporate training and engineering interventions that reduce sustained non-neutral wrist postures.
authors.affiliation: Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA.
authors.forename: Doohee
authors.initials: D
authors.lastname: You
authors.affiliation: Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA.
authors.forename: Allan H
authors.initials: AH
authors.lastname: Smith
authors.affiliation: Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA ; Division of Occupational and Environmental Medicine, University of California, San Francisco, CA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Rempel
keywords: carpal tunnel syndrome; meta-analysis; systematic review