title: Increased illness experience preceding chronic fatigue syndrome: a case control study.
abstract: BACKGROUND
  Almost all published work on chronic fatigue syndrome (CFS) has involved retrospective surveys of cases, which may introduce recall bias. Only medical records collected before diagnosis of CFS can eliminate this.
  
  
  METHODS
  Using data collected several years prior to the development of the illness, we performed a case control study, comparing the reported illness records of all people who subsequently made an insurance claim as a result of CFS, with those of future multiple sclerosis (MS) claimants, and those of non-claimant controls (NC).
  
  
  RESULTS
  The study encompassed 133 CFS, 75 MS and 162 NC cases. CFS cases had recorded significantly more illnesses at time of proposal for insurance than the two control groups, and had significantly more claims between proposal and diagnosis of their disorder. Almost all disease categories were reported higher in future CFS sufferers, lethargy having the highest odds ratio after adjustment in a multivariate model.
  
  
  CONCLUSIONS
  The results of this paper on CFS patients who claim permanent health insurance do not support a specific viral or immunological explanation for CFS. We conclude that abnormal illness behaviour is of greater importance than previously recognised.
authors.forename: G H
authors.initials: GH
authors.lastname: Hall
authors.forename: W T
authors.initials: WT
authors.lastname: Hamilton
authors.forename: A P
authors.initials: AP
authors.lastname: Round
mesh_terms: D000328:Adult; D000367:Age Factors; D016022:Case-Control Studies; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006801:Humans; D007345:Insurance Claim Review; D016015:Logistic Models; D008297:Male; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000209:etiology; D015999:Multivariate Analysis; D016017:Odds Ratio; D012737:Sex Factors