title: Overlapping conditions among patients with chronic fatigue syndrome, fibromyalgia, and temporomandibular disorder.
abstract: BACKGROUND
  Patients with chronic fatigue syndrome (CFS), fibromyalgia (FM), and temporomandibular disorder (TMD) share many clinical illness features such as myalgia, fatigue, sleep disturbances, and impairment in ability to perform activities of daily living as a consequence of these symptoms. A growing literature suggests that a variety of comorbid illnesses also may commonly coexist in these patients, including irritable bowel syndrome, chronic tension-type headache, and interstitial cystitis.
  
  
  OBJECTIVE
  To describe the frequency of 10 clinical conditions among patients with CFS, FM, and TMD compared with healthy controls with respect to past diagnoses, degree to which they manifested symptoms for each condition as determined by expert-based criteria, and published diagnostic criteria.
  
  
  METHODS
  Patients diagnosed as having CFS, FM, and TMD by their physicians were recruited from hospital-based clinics. Healthy control subjects from a dermatology clinic were enrolled as a comparison group. All subjects completed a 138-item symptom checklist and underwent a brief physical examination performed by the project physicians.
  
  
  RESULTS
  With little exception, patients reported few past diagnoses of the 10 clinical conditions beyond their referring diagnosis of CFS, FM, or TMD. In contrast, patients were more likely than controls to meet lifetime symptom and diagnostic criteria for many of the conditions, including CFS, FM, irritable bowel syndrome, multiple chemical sensitivities, and headache. Lifetime rates of irritable bowel syndrome were particularly striking in the patient groups (CFS, 92%; FM, 77%; TMD, 64%) compared with controls (18%) (P<.001). Individual symptom analysis revealed that patients with CFS, FM, and TMD share common symptoms, including generalized pain sensitivity, sleep and concentration difficulties, bowel complaints, and headache. However, several symptoms also distinguished the patient groups.
  
  
  CONCLUSIONS
  This study provides preliminary evidence that patients with CFS, FM, and TMD share key symptoms. It also is apparent that other localized and systemic conditions may frequently co-occur with CFS, FM, and TMD. Future research that seeks to identify the temporal relationships and other pathophysiologic mechanism(s) linking CFS, FM, and TMD will likely advance our understanding and treatment of these chronic, recurrent conditions.
authors.affiliation: Department of Medicine, University of Washington, Seattle, USA. laaron@u.washington.edu
authors.forename: L A
authors.initials: LA
authors.lastname: Aaron
authors.forename: M M
authors.initials: MM
authors.lastname: Burke
authors.forename: D
authors.initials: D
authors.lastname: Buchwald
mesh_terms: D000328:Adult; D015897:Comorbidity; D003937:Diagnosis, Differential; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D005356:Fibromyalgia / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010808:Physical Examination / Q000145:classification*; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology