title: Cumulative occupational shoulder exposures and surgery for subacromial impingement syndrome: a nationwide Danish cohort study.
abstract: OBJECTIVE
  The primary aim was to examine exposure-response relationships between cumulative occupational shoulder exposures and surgery for subacromial impingement syndrome (SIS), and to compare sex-specific exposure-response relationships. The secondary aim was to examine the time window of relevant exposures.
  
  
  METHODS
  We conducted a nationwide register study of all persons born in Denmark (1933-1977), who had at least 5 years of full-time employment. In the follow-up period (2003-2008), we identified first-time events of surgery for SIS. Cumulative exposure estimates for a 10-year exposure time window with a 1-year lag time were obtained by linking occupational codes with a job exposure matrix. The exposure estimates were expressed as, for example, arm-elevation-years in accordance with the pack-year concept of tobacco consumption. We used a multivariable logistic regression technique equivalent to discrete survival analysis.
  
  
  RESULTS
  The adjusted OR (ORadj) increased to a maximum of 2.1 for arm-elevation-years, repetition-years and force-years, and to 1.5 for hand-arm-vibration-years. Sex-specific exposure-response relationships were similar for men and women, when assessed using a relative risk scale. The ORadj increased gradually with the number of years contributing to the cumulative exposure estimates. The excess fraction was 24%.
  
  
  CONCLUSIONS
  Cumulative occupational shoulder exposures carried an increase in risk of surgery for SIS with similar exposure-response curves for men and women. The risk of surgery for SIS increased gradually, when the period of exposure assessment was extended. In the general working population, a substantial fraction of all first-time operations for SIS could be related to occupational exposures.
authors.affiliation: Department of Occupational Medicine, Danish Ramazzini Centre, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Annett
authors.initials: A
authors.lastname: Dalbøge
authors.affiliation: Department of Occupational Medicine, Danish Ramazzini Centre, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Poul
authors.initials: P
authors.lastname: Frost
authors.affiliation: Department of Occupational Medicine, Regional Hospital West Jutland-University Research Clinic, Herning, Denmark.
authors.forename: Johan Hviid
authors.initials: JH
authors.lastname: Andersen
authors.affiliation: Department of Occupational Medicine, Regional Hospital West Jutland-University Research Clinic, Herning, Denmark.
authors.forename: Susanne Wulff
authors.initials: SW
authors.lastname: Svendsen
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D015331:Cohort Studies; D012090:Cumulative Trauma Disorders; D003718:Denmark; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009068:Movement; D009784:Occupational Diseases / Q000209:etiology* / Q000601:surgery; D016273:Occupational Exposure / Q000009:adverse effects*; D016017:Odds Ratio; D012737:Sex Factors; D012782:Shoulder; D019534:Shoulder Impingement Syndrome / Q000209:etiology* / Q000601:surgery; D013314:Stress, Mechanical; D013997:Time Factors; D014732:Vibration; D055815:Young Adult
keywords: Acromioplasty; Job exposure matrix; Sex; Shoulder disorders; Time window