A case-control study to assess possible triggers and cofactors in chronic fatigue syndrome

Am J Med. 1996 May;100(5):548-54. doi: 10.1016/s0002-9343(96)00017-4.

Abstract

Purpose: To assess possible triggers and cofactors for chronic fatigue syndrome (CFS) and to compare levels of selected cytokines between cases and an appropriately matched control group.

Patients and methods: We conducted a case-control study of 47 cases of CFS obtained through a regional CFS research program maintained at a tertiary care medical center. One age-, gender-, and neighborhood-matched control was identified for each case through systematic community telephone sampling. Standardized questionnaires were administered to cases and controls. Sera were assayed for transforming growth factor-beta (TGF-beta), interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, and antibody to Borrelia burgdorferi and Babesia microti.

Results: Cases were more likely to have exercised regularly before illness onset than controls (67% versus 40%; matched odds ratio (MOR) = 3.4; 95% CI = 1.2 to 11.8; P = 0.02). Female cases were more likely to be nulliparous prior to onset of CFS than controls (51% versus 31%; MOR = 8.0; 95% CI = 1.03 to 170; P = 0.05). History of other major factors, including silicone-gel breast implants (one female case and one female control), pre-morbid history of depression (15% of cases, 11% of controls) and history of allergies (66% of cases, 51% of controls) were similar for cases and controls. However, cases were more likely to have a diagnosis of depression subsequent to their diagnosis of CFS compared to a similar time frame for controls (MOR = undefined; 95% CI lower bound = 2.5; P < 0.001). Positive antibody titers to B burgdorferi (one case and one control) and B microti (zero cases and two controls) were also similar.

Conclusions: Further investigation into the role of prior routine exercise as a cofactor for CFS is warranted. This study supports the concurrence of CFS and depression, although pre-morbid history of depression was similar for both groups.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Animals
  • Antibodies, Bacterial / analysis
  • Antibodies, Protozoan / analysis
  • Babesia / immunology
  • Borrelia burgdorferi Group / immunology
  • Case-Control Studies
  • Data Interpretation, Statistical
  • Depression / complications
  • Fatigue Syndrome, Chronic / blood
  • Fatigue Syndrome, Chronic / etiology*
  • Female
  • Humans
  • Hypersensitivity / complications
  • Interleukin-1 / blood
  • Interleukin-6 / blood
  • Male
  • Middle Aged
  • Parity
  • Physical Exertion
  • Risk Factors
  • Surveys and Questionnaires
  • Time Factors
  • Transforming Growth Factor beta / blood
  • Tumor Necrosis Factor-alpha / analysis

Substances

  • Antibodies, Bacterial
  • Antibodies, Protozoan
  • Interleukin-1
  • Interleukin-6
  • Transforming Growth Factor beta
  • Tumor Necrosis Factor-alpha