Conditions comorbid with chronic fatigue in a population-based sample.
BACKGROUND
Chronic fatigue syndrome (CFS) has been found to be comorbid with various medical conditions in clinical samples, but little research has investigated CFS comorbidity in population-based samples.


OBJECTIVE
This study investigated conditions concurrent with a CFS-like illness among twins in the population-based Mid-Atlantic Twin Registry (MATR), including chronic widespread pain (CWP), irritable bowel syndrome (IBS), and major depressive disorder (MDD).


METHODS
A survey was mailed to participants in the MATR in 1999. Generalized estimating equations were used to estimate odds ratios to assess associations between CFS-like illness and each comorbid condition.


RESULTS
A total of 4590 completed surveys were collected. Most participants were female (86.3%); mean age was 44.7 years. Among participants with a CFS-like illness, lifetime prevalences of CWP, IBS, and MDD were 41%, 16%, and 57% respectively. Participants reporting at least one of the three comorbid conditions were about 14 times more likely to have CFS-like illness than those without CWP, IBS, or MDD (95% confidence interval 8.1%-21.3%). Only MDD showed a temporal pattern of presentation during the same year as diagnosis of CFS-like illness. Age, gender, body mass index, age at illness onset, exercise level, self-reported health status, fatigue symptoms, and personality measures did not differ between those reporting CFS-like illness with and without comorbidity.


CONCLUSIONS
These results support findings in clinically based samples that CFS-like illness is frequently cormorbid with CWP, IBS, and/or MDD. We found no evidence that CFS-like illnesses with comorbidities are clinically distinct from those without comorbidities.
Center for Clinical and Epidemiological Research, University of Washington, Seattle, WA 98101, USA. Edansie@uw.edu
Elizabeth J
EJ
Dansie
Helena
H
Furberg
Niloofar
N
Afari
Dedra
D
Buchwald
Karen
K
Edwards
Jack
J
Goldberg
Ellen
E
Schur
Patrick F
PF
Sullivan
D000328:Adult; D015982:Bias; D002908:Chronic Disease; D059350:Chronic Pain / Q000453:epidemiology*; D015897:Comorbidity; D003865:Major Depressive Disorder / Q000453:epidemiology*; D004200:Diseases in Twins; D004812:Epidemiologic Methods; D015673:Fatigue Syndrome, Chronic / Q000453:epidemiology*; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000453:epidemiology*; D008297:Male; D010552:Personality Assessment; D011788:Quality of Life; D014481:United States / Q000453:epidemiology