title: Work stress, worries, and pain interact synergistically with modelled traffic noise on cross-sectional associations with self-reported sleep problems.
abstract: OBJECTIVE
  To examine the risk of sleep problems associated with work stress (job strain, job demands, and decision authority), worries and pain and to investigate the synergistic interaction between these factors and traffic noise.
  
  
  METHODS
  Sleep problems and predictor variables were assessed in a cross-sectional public health survey with 12,093 respondents. Traffic noise levels were assessed using modelled A-weighted energy equivalent traffic sound levels at the residence. The risk of sleep problems was modelled using multiple logistic regression analysis.
  
  
  RESULTS
  With regard to sleep problems not attributed to any external source (general sleep problems), independent main effects were found for traffic noise (women), decision authority (women), job strain, job demands, suffering from pain or other afflictions, worries about losing the job, experiencing bullying at work, having troubles paying the bills, and having a sick, disabled, or old relative to take care of (women). Significant synergistic effects were found for traffic noise and experiencing bullying at work in women. With regard to sleep problems attributed to traffic noise, strong synergistic interactions were found between traffic noise and, respectively, job demands (men), having pain or other afflictions, taking care of a sick, old, or disabled relative, and having troubles paying the bills. Main effects were found for worries about losing the job, experiencing bullying at work, job strain (men), and decision authority (men). Synergistic interactions could potentially contribute with 10-20% of the sleep problems attributed to traffic noise in the population.
  
  
  CONCLUSIONS
  Work stress, pain, and different worries were independently associated with general sleep problems and showed in general no synergistic interaction with traffic noise. In contrast, synergistic effects between traffic noise and psychological factors were found with regard to sleep problems attributed to traffic noise. The synergy may contribute significantly to sleep problems attributed to traffic noise in the population.
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen, Denmark. jkr@nrcwe.dk
authors.forename: Jesper
authors.initials: J
authors.lastname: Kristiansen
authors.forename: Roger
authors.initials: R
authors.lastname: Persson
authors.forename: Jonas
authors.initials: J
authors.lastname: Björk
authors.forename: Maria
authors.initials: M
authors.lastname: Albin
authors.forename: Kristina
authors.initials: K
authors.lastname: Jakobsson
authors.forename: Per-Olof
authors.initials: PO
authors.lastname: Ostergren
authors.forename: Jonas
authors.initials: J
authors.lastname: Ardö
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007588:Job Satisfaction; D008297:Male; D008875:Middle Aged; D009624:Noise, Transportation / Q000009:adverse effects*; D010146:Pain / Q000150:complications*; D012737:Sex Factors; D012893:Sleep Wake Disorders / Q000209:etiology*; D018709:Statistics, Nonparametric; D013315:Stress, Psychological / Q000150:complications*; D011795:Surveys and Questionnaires; D013548:Sweden; D016526:Workload / Q000523:psychology*; D055815:Young Adult