title: Subacromial shoulder disorders among baggage handlers: an observational cohort study.
abstract: OBJECTIVE
  To assess the influence of cumulative employment as baggage handler on the risk of incident subacromial shoulder disorders. Baggage handling is characterized by repetitive work primarily consisting of heavy lifting in awkward positions and time pressure.
  
  
  METHODS
  This cohort study is based on the Copenhagen Airport Cohort consisting of unskilled men with employment at Copenhagen Airport and unskilled men with employment in other firms in the Greater Copenhagen area during the period 1990-2012. Only men were included. We followed the cohort in the National Patient Register and Civil Registration System. The primary exposure was cumulative years of employment as a baggage handler, and the primary outcome was diagnoses and surgical treatment of subacromial shoulder disorders.
  
  
  RESULTS
  The cohort contained 3396 baggage handlers and 63,909 workers in the reference group. Baggage handlers with longer cumulative years of employment had higher incidence compared to baggage handlers with shorter employment; for example, baggage handlers with 10-19 years of employment had incidence rate ratio of 2.07 (95 % confidence interval, 1.27-3.38) compared to baggage handlers with less than 3 years of employment. Spline regression showed an increase in incidence within the first few years after employment whereupon the increased risk remained constant for longer employment. Baggage handlers had increased incidence in younger ages than the reference population.
  
  
  CONCLUSIONS
  In this large cohort study, we found increased incidence of subacromial shoulder disorders for workers with longer cumulative years of employment. These results support that long-term lifting in awkward positions and time pressure influences the risk of subacromial shoulder disorders.
authors.affiliation: National Institute of Public Health, University of Southern Denmark, Øster Farimagsgade 5, 1353, Copenhagen, Denmark. lct@niph.dk.
authors.forename: Lau Caspar
authors.initials: LC
authors.lastname: Thygesen
authors.affiliation: Department of Occupational and Environmental Medicine, Copenhagen University Hospital, Bispebjerg, Bispebjerg Bakke 23, 2400, Copenhagen, Denmark.
authors.forename: Sigurd
authors.initials: S
authors.lastname: Mikkelsen
authors.affiliation: Department of Occupational and Environmental Medicine, Copenhagen University Hospital, Bispebjerg, Bispebjerg Bakke 23, 2400, Copenhagen, Denmark.
authors.forename: Ellen Bøtker
authors.initials: EB
authors.lastname: Pedersen
authors.affiliation: National Institute of Public Health, University of Southern Denmark, Øster Farimagsgade 5, 1353, Copenhagen, Denmark.
authors.forename: Karina Lauenborg
authors.initials: KL
authors.lastname: Møller
authors.affiliation: Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark.
authors.forename: Tine
authors.initials: T
authors.lastname: Alkjær
authors.affiliation: Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Koblauch
authors.affiliation: Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark.
authors.forename: Erik B
authors.initials: EB
authors.lastname: Simonsen
authors.affiliation: National Institute of Public Health, University of Southern Denmark, Øster Farimagsgade 5, 1353, Copenhagen, Denmark.
authors.forename: Sanne Pagh
authors.initials: SP
authors.lastname: Møller
authors.affiliation: Department of Occupational and Environmental Medicine, Copenhagen University Hospital, Bispebjerg, Bispebjerg Bakke 23, 2400, Copenhagen, Denmark.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Brauer
mesh_terms: D000328:Adult; D000367:Age Factors; D064870:Air Travel; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D017770:Lifting / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D012042:Registries; D012307:Risk Factors; D019534:Shoulder Impingement Syndrome / Q000453:epidemiology* / Q000209:etiology; D013997:Time Factors
keywords: Cohort studies; Epidemiology; Occupation; Registries; Shoulder