title: Health and functional status of twins with chronic regional and widespread pain.
abstract: OBJECTIVE
  To examine the independent effects of chronic regional and widespread pain syndromes on health and functional status after accounting for comorbid chronic fatigue using a co-twin control design.
  
  
  METHODS
  We identified 95 twin pairs discordant for pain in which one twin had chronic regional or widespread pain and the other denied chronic pain. Demographic data, functional and psychological status, health behaviors, and symptoms based on the 1994 criteria for chronic fatigue syndrome (CFS) were assessed by questionnaire. Psychiatric diagnoses were based on structured interview. Random effects regression modeling estimated associations between chronic regional and widespread pain and each health measure with and without adjustment for CFS.
  
  
  RESULTS
  Significant differences (p </= 0.05) were found within twin pairs discordant for chronic regional and widespread pain, for general health perception, and physical and mental health functioning as measured by summary scores from the Short Form-36. In addition, differences were observed within pain discordant pairs in psychological distress as measured by the General Health Questionnaire as well as the number of psychiatric diagnoses. Adjustment for CFS eliminated the association between chronic pain and mental health, but the association between chronic pain and poor general health, physical functioning, and sleep quality persisted (p </= 0.01). Only the intra-pair difference in physical functioning distinguished twins with regional vs widespread pain (p </= 0.05).
  
  
  CONCLUSIONS
  Both chronic regional and widespread pain exact debilitating effects on perceived general health, physical functioning, and sleep quality independent of CFS. However, the psychological and psychiatric influence of chronic pain appears closely tied to CFS. Research should examine the additive role of CFS-like illnesses in patients with chronic pain, and its influence on treatment and outcome.
authors.affiliation: Department of Oral Medicine, University of Washington, Seattle, Washington 98195, USA. laaron@u.washington.edu
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Aaron
authors.forename: Lester M
authors.initials: LM
authors.lastname: Arguelles
authors.forename: Suzanne
authors.initials: S
authors.lastname: Ashton
authors.forename: Megan
authors.initials: M
authors.lastname: Belcourt
authors.forename: Richard
authors.initials: R
authors.lastname: Herrell
authors.forename: Jack
authors.initials: J
authors.lastname: Goldberg
authors.forename: Wayne R
authors.initials: WR
authors.lastname: Smith
authors.forename: Debra
authors.initials: D
authors.lastname: Buchwald
authors.forename: Dedra
authors.initials: D
authors.lastname: Buchwald
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D002908:Chronic Disease; D004200:Diseases in Twins; D015673:Fatigue Syndrome, Chronic / Q000503:physiopathology / Q000523:psychology; D005260:Female; D005356:Fibromyalgia / Q000503:physiopathology / Q000523:psychology; D015438:Health Behavior; D006304:Health Status; D006801:Humans; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology* / Q000523:psychology; D012923:Social Class; D011795:Surveys and Questionnaires