title: Do exposure limits for hand-transmitted vibration prevent carpal tunnel syndrome?
abstract: BACKGROUND
  An apparently high frequency of carpal tunnel syndrome (CTS) among shipyard workers undergoing health surveillance because of exposure to hand-transmitted vibration (HTV) prompted concerns that current regulatory limits on exposure might not protect adequately against the disorder.
  
  
  OBJECTIVE
  To explore whether within regulatory limits, higher exposures to HTV predispose to CTS.
  
  
  METHODS
  As part of a retrospective audit, we compared duration and current intensity of exposure to HTV in cases with new-onset CTS and controls matched for age. Conditional logistic regression was used to quantify associations, which were summarized by odds ratios (ORs) and 95% confidence intervals (CIs).
  
  
  RESULTS
  There were 23 cases and 55 controls. After adjustment for body mass index and previous diagnosis of diabetes, no clear associations were observed either with duration of exposure to HTV or with current intensity of exposure. Risk was non-significantly elevated in men with ≥30 years' exposure to HTV (OR 1.6), but in the highest category of current exposure [8-h energy-equivalent frequency-weighted acceleration (A8) ≥ 4.0 m/s(2)], risk was lower than that in the reference category (A8 < 2.5 m/s(2)). Moreover, there was a significantly reduced risk of CTS in men with a previous diagnosis of hand-arm vibration syndrome (HAVS) (OR 0.2, 95% CI 0.1-0.9).
  
  
  CONCLUSIONS
  We found no evidence that below the current limit for A(8) of 5 m/s(2), higher exposures to HTV predispose to CTS. However, care should be taken not to overlook the possibility of treatable CTS when workers with diagnosed HAVS present with new or worsening sensory symptoms in the hand.
authors.affiliation: Independent Occupational Physician, Southampton, UK.
authors.forename: S
authors.initials: S
authors.lastname: Gillibrand
authors.affiliation: Arthritis Research-UK/MRC Centre for Musculoskeletal Health and Work, University of Southampton, Southampton SO16 6YD, UK, MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton SO16 6YD, UK.
authors.forename: G
authors.initials: G
authors.lastname: Ntani
authors.affiliation: Arthritis Research-UK/MRC Centre for Musculoskeletal Health and Work, University of Southampton, Southampton SO16 6YD, UK, MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton SO16 6YD, UK. dnc@mrc.soton.ac.uk.
authors.forename: D
authors.initials: D
authors.lastname: Coggon
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002349:Carpal Tunnel Syndrome / Q000517:prevention & control*; D003920:Diabetes Mellitus / Q000175:diagnosis; D053421:Hand-Arm Vibration Syndrome / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000209:etiology*; D016273:Occupational Exposure / Q000009:adverse effects; D011159:Population Surveillance / Q000379:methods; D012189:Retrospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014732:Vibration / Q000009:adverse effects*
keywords: Carpal tunnel syndrome; hand-arm vibration syndrome; hand-transmitted vibration; occupation; regulatory controls.