title: C-reactive protein and pain sensitivity: findings from female twins.
abstract: BACKGROUND
  Systemic inflammation and pain sensitivity may contribute to the development and maintenance of chronic pain conditions.
  
  
  OBJECTIVE
  We examined the relationship between systemic inflammation as measured by C-reactive protein (CRP) and cold pain sensitivity in 198 female twins from the University of Washington Twin Registry. We also explored the potential role of familial factors in this relationship.
  
  
  METHODS
  Linear regression modeling with generalized estimating equations examined the overall and within-pair associations.
  
  
  RESULTS
  Higher levels of CRP were associated with higher pain sensitivity ratings at pain threshold (p = 0.02) and tolerance (p = 0.03) after adjusting for age, body mass index, time to reach pain threshold or tolerance, and clinical pain status. The magnitude of the associations remained the same in within-pair analyses controlling for familial factors.
  
  
  CONCLUSIONS
  The link between CRP and pain sensitivity may be due to non-shared environmental factors. CRP and pain sensitivity can be examined as potential biomarkers for chronic pain and other inflammatory conditions.
authors.affiliation: Department of Psychiatry, University of California-San Diego and VA San Diego Healthcare System, 9500 Gilman Drive, La Jolla, CA 92093, USA. nafari@ucsd.edu
authors.forename: Niloofar
authors.initials: N
authors.lastname: Afari
authors.forename: Sheeva
authors.initials: S
authors.lastname: Mostoufi
authors.forename: Carolyn
authors.initials: C
authors.lastname: Noonan
authors.forename: Brian
authors.initials: B
authors.lastname: Poeschla
authors.forename: Annemarie
authors.initials: A
authors.lastname: Succop
authors.forename: Laura
authors.initials: L
authors.lastname: Chopko
authors.forename: Eric
authors.initials: E
authors.lastname: Strachan
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D059350:Chronic Pain / Q000097:blood / Q000503:physiopathology; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood; D015233:Models, Statistical; D017288:Pain Threshold / Q000502:physiology*; D014427:Twins / Q000706:statistics & numerical data*
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein