Health and Functional Status of Twins with Chronic Regional and
Widespread Pain.

J Rheumatol 2002 Nov;29(11):2426-2434

Aaron LA, Arguelles LM, Ashton S, Belcourt M, Herrell R,
Goldberg J, Smith WR, Buchwald D.

Affiliation: Department of Oral Medicine, University of Washington,
Seattle, Washington, USA.

NLM Citation: PMID: 12415604


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).

CONCLUSION: 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.