title: Comparison of alternative versions of the job demand-control scales in 17 European cohort studies: the IPD-Work consortium.
abstract: BACKGROUND
  Job strain (i.e., high job demands combined with low job control) is a frequently used indicator of harmful work stress, but studies have often used partial versions of the complete multi-item job demands and control scales. Understanding whether the different instruments assess the same underlying concepts has crucial implications for the interpretation of findings across studies, harmonisation of multi-cohort data for pooled analyses, and design of future studies. As part of the 'IPD-Work' (Individual-participant-data meta-analysis in working populations) consortium, we compared different versions of the demands and control scales available in 17 European cohort studies.
  
  
  METHODS
  Six of the 17 studies had information on the complete scales and 11 on partial scales. Here, we analyse individual level data from 70 751 participants of the studies which had complete scales (5 demand items, 6 job control items).
  
  
  RESULTS
  We found high Pearson correlation coefficients between complete scales of job demands and control relative to scales with at least three items (r > 0.90) and for partial scales with two items only (r = 0.76-0.88). In comparison with scores from the complete scales, the agreement between job strain definitions was very good when only one item was missing in either the demands or the control scale (kappa > 0.80); good for job strain assessed with three demand items and all six control items (kappa > 0.68) and moderate to good when items were missing from both scales (kappa = 0.54-0.76). The sensitivity was > 0.80 when only one item was missing from either scale, decreasing when several items were missing in one or both job strain subscales.
  
  
  CONCLUSIONS
  Partial job demand and job control scales with at least half of the items of the complete scales, and job strain indices based on one complete and one partial scale, seemed to assess the same underlying concepts as the complete survey instruments.
authors.affiliation: Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm, Sweden. eleonor.fransson@ki.se
authors.forename: Eleonor I
authors.initials: EI
authors.lastname: Fransson
authors.forename: Solja T
authors.initials: ST
authors.lastname: Nyberg
authors.forename: Katriina
authors.initials: K
authors.lastname: Heikkilä
authors.forename: Lars
authors.initials: L
authors.lastname: Alfredsson
authors.forename: De Dirk
authors.initials: de D
authors.lastname: Bacquer
authors.forename: G David
authors.initials: GD
authors.lastname: Batty
authors.forename: Sébastien
authors.initials: S
authors.lastname: Bonenfant
authors.forename: Annalisa
authors.initials: A
authors.lastname: Casini
authors.forename: Els
authors.initials: E
authors.lastname: Clays
authors.forename: Marcel
authors.initials: M
authors.lastname: Goldberg
authors.forename: France
authors.initials: F
authors.lastname: Kittel
authors.forename: Markku
authors.initials: M
authors.lastname: Koskenvuo
authors.forename: Anders
authors.initials: A
authors.lastname: Knutsson
authors.forename: Constanze
authors.initials: C
authors.lastname: Leineweber
authors.forename: Linda L
authors.initials: LL
authors.lastname: Magnusson Hanson
authors.forename: Maria
authors.initials: M
authors.lastname: Nordin
authors.forename: Archana
authors.initials: A
authors.lastname: Singh-Manoux
authors.forename: Sakari
authors.initials: S
authors.lastname: Suominen
authors.forename: Jussi
authors.initials: J
authors.lastname: Vahtera
authors.forename: Peter
authors.initials: P
authors.lastname: Westerholm
authors.forename: Hugo
authors.initials: H
authors.lastname: Westerlund
authors.forename: Marie
authors.initials: M
authors.lastname: Zins
authors.forename: Töres
authors.initials: T
authors.lastname: Theorell
authors.forename: Mika
authors.initials: M
authors.lastname: Kivimäki
mesh_terms: D015331:Cohort Studies; D005060:Europe / Q000453:epidemiology; D006801:Humans; D007389:Internal-External Control; D016273:Occupational Exposure; D013315:Stress, Psychological / Q000453:epidemiology / Q000209:etiology*; D011795:Surveys and Questionnaires