title: Sleep as a predictive factor for the onset and resolution of multi-site pain: a 5-year prospective study.
abstract: BACKGROUND
  Disturbed sleep and pain often co-exist and the relationship between the two conditions is complex and likely reciprocal. This 5-year prospective study examines whether disturbed sleep can predict the onset of multi-site pain, and whether non-disturbed sleep can predict the resolution of multi-site pain.
  
  
  METHODS
  The cohort (n = 1599) was stratified by the number of self-reported pain sites: no pain, pain from 1-2 sites and multi-site pain (≥3 pain sites). Sleep was categorized by self-reported sleep disturbance: sleep A (best sleep), sleep B and sleep C (worst sleep). In the no-pain and pain-from-1-2 sites strata, the association between sleep (A, B and C) and multi-site pain 5 years later was analysed. Further, the prognostic value of sleep for the resolution of multi-site pain at follow-up was calculated for the stratum with multi-site pain at baseline. In the analyses, gender, age, body mass index, smoking, physical activity and work-related exposures were treated as potential confounders.
  
  
  RESULTS
  For individuals with no pain at baseline, a significantly higher odds ratio for multi-site pain 5 years later was seen for the tertile reporting worst sleep [odds ratio (OR) 4.55; 95% confidence interval (CI) 1.28-16.12]. Non-disturbed (or less disturbed) sleep had a significant effect when predicting the resolution of multi-site pain (to no pain) (OR 3.96; 95% CI 1.69-9.31).
  
  
  CONCLUSIONS
  In conclusion, sleep could be relevant for predicting both the onset and the resolution of multi-site pain. It seems to be a significant factor to include in research on multi-site pain and when conducting or evaluating intervention programmes for pain.
authors: Institute of Environmental Medicine, Karolinska Institutet, Sweden.
authors: K
authors: K
authors: Aili
authors: T
authors: T
authors: Nyman
authors: M
authors: M
authors: Svartengren
authors: L
authors: L
authors: Hillert
mesh_terms: D000328:Adult; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000453:epidemiology / Q000503:physiopathology*; D011446:Prospective Studies; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000453:epidemiology / Q000503:physiopathology*; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult