title: Effort-reward imbalance at work and risk of sleep disturbances. Cross-sectional and prospective results from the Danish Work Environment Cohort Study.
abstract: OBJECTIVE
  This study aimed to analyze if adverse psychosocial working conditions, defined by the model of effort-reward imbalance (ERI), increase the risk of sleep disturbances in the Danish workforce.
  
  
  METHODS
  Analyses were conducted both cross-sectionally and prospectively in a representative sample of Danish employees. The cross-sectional sample included 2614 participants (50% women) aged 18-59 years, of whom 263 had sleep disturbances. Of the 2351 participants initially free of sleep disturbances, 304 (12.9%) developed sleep disturbances during the 5-year follow-up. Data were analyzed with gender-stratified, multivariate logistic and linear regression analyses, adjusted for numerous covariates.
  
  
  RESULTS
  Cross-sectionally, a 1 S.D. increase in the ERI ratio was associated with sleep disturbances among both men [odds ratio (OR)=1.65, 95% confidence interval (CI)=1.20-2.27] and women (OR=1.82, 95% CI=1.46-2.28). In the prospective analysis, a 1 S.D. increase of the ERI ratio at baseline predicted the onset of sleep disturbances among men (OR=1.39, 95% CI=1.03-1.87) but not among women (OR=0.97, 95% CI=0.76-1.24).
  
  
  CONCLUSIONS
  Among men, ERI is a risk factor for the development of sleep disturbances in the Danish workforce. Among women, an association between ERI and sleep disturbances was restricted to the cross-sectional sample. Improving psychosocial working conditions might reduce the risk of sleep disturbances and subsequently also help to prevent clinical disorders related to sleep disturbances.
authors.affiliation: National Research Centre for the Working Environment, Copenhagen, Denmark. rer@nrcwe.dk
authors.forename: Reiner
authors.initials: R
authors.lastname: Rugulies
authors.forename: Malene
authors.initials: M
authors.lastname: Norborg
authors.forename: Tilde Sand
authors.initials: TS
authors.lastname: Sørensen
authors.forename: Lisbeth E
authors.initials: LE
authors.lastname: Knudsen
authors.forename: Hermann
authors.initials: H
authors.lastname: Burr
mesh_terms: D000293:Adolescent; D000328:Adult; D002322:Career Mobility; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003718:Denmark; D005260:Female; D006801:Humans; D007588:Job Satisfaction; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009784:Occupational Diseases / Q000453:epidemiology / Q000523:psychology*; D011446:Prospective Studies; D012201:Reward; D012307:Risk Factors; D012456:Salaries and Fringe Benefits; D012649:Self Concept; D012737:Sex Factors; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology / Q000523:psychology*; D016526:Workload / Q000523:psychology*; D055815:Young Adult