title: Arm/shoulder problems and insomnia symptoms in breast cancer survivors: cross-sectional, controlled and longitudinal observations.
abstract: OBJECTIVE
  In breast cancer survivors (BCSs) the relation between insomnia symptoms and arm/shoulder problems has hardly been investigated. In cross-sectional and longitudinal designs we examined this association in BCSs and in comparison to age-matched controls from the general population.
  
  
  METHODS
  Our cross-sectional sample consisted of 337 BCSs stage II/III studied in 2004 at a median of 3.9 years after surgery combined with adjuvant radiotherapy and cytostatics/hormones. In 2007 248 (74%) BCSs were re-examined (median 2.5 years later). The responses of the 2004 sample were compared to those of 1685 controls.
  
  
  RESULTS
  Thirty percent of BCSs reported insomnia symptoms in 2004, and arm/shoulder problems were significantly associated with insomnia, as were established variables in bivariate analyses. In 2004 only regular use of hypnotics remained associated with insomnia in multivariate analysis. In bivariate analysis arm/shoulder pain and restricted mobility in 2004 were significant predictors of insomnia in 2007. Only insomnia in 2004 was a significant predictor in multivariate analysis. In bivariate analyses BCSs and controls had several common factors associated with insomnia, but only regular use of hypnotics was common in multivariate analysis.
  
  
  CONCLUSIONS
  Arm/shoulder problems are factors to consider in BCSs with insomnia, particularly arm/shoulder pain. Factors associated with insomnia in BCSs and general population controls are partially overlapping.
authors.affiliation: National Resource Center for Late Effects, Department of Oncology, Oslo University Hospital and University of Oslo, Oslo, Norway. a.a.dahl@imbv.uio.no
authors.forename: Alv A
authors.initials: AA
authors.lastname: Dahl
authors.forename: Inger-Lise
authors.initials: IL
authors.lastname: Nesvold
authors.forename: Kristin Valborg
authors.initials: KV
authors.lastname: Reinertsen
authors.forename: Sophie D
authors.initials: SD
authors.lastname: Fosså
mesh_terms: D000328:Adult; D000368:Aged; D001132:Arm / Q000502:physiology; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000532:radiotherapy; D003430:Cross-Sectional Studies; D005221:Fatigue / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008209:Lymphedema / Q000453:epidemiology* / Q000503:physiopathology; D008875:Middle Aged; D015995:Prevalence; D012782:Shoulder / Q000502:physiology; D020069:Shoulder Pain / Q000453:epidemiology* / Q000503:physiopathology; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology*; D017741:Survivors / Q000706:statistics & numerical data