Psychological Medicine

Original Articles

Risk markers for both chronic fatigue and irritable bowel syndromes: a prospective case-control study in primary care

W. T. Hamiltona1, A. M. Gallaghera2, J. M. Thomasa2 and P. D. Whitea2 c1

a1 Academic Unit of Primary Health Care, University of Bristol, Bristol, UK

a2 Centre for Psychiatry, Wolfson Institute of Preventive Medicine, Bart's and the London, Queen Mary School of Medicine and Dentistry, London, UK


Background Fatigue syndromes and irritable bowel syndrome (IBS) often occur together. Explanations include being different manifestations of the same condition and simply sharing some symptoms.

Method A matched case-control study in UK primary care, using data collected prospectively in the General Practice Research Database (GPRD). The main outcome measures were: health-care utilization, specific symptoms and diagnoses. Risk markers were divided into distant (from 3 years to 1 year before diagnosis) and recent (1 year before diagnosis).

Results A total of 4388 patients with any fatigue syndrome were matched to two groups of patients: those attending for IBS and those attending for another reason. Infections were specific risk markers for both syndromes, with viral infections being a risk marker for a fatigue syndrome [odds ratios (ORs) 2.3–6.3], with a higher risk closer to onset, and gastroenteritis a risk for IBS (OR 1.47, compared to a fatigue syndrome). Chronic fatigue syndrome (CFS) shared more distant risk markers with IBS than other fatigue syndromes, particularly other symptom-based disorders (OR 3.8) and depressive disorders (OR 2.3), but depressive disorders were a greater risk for CFS than IBS (OR 2.4). Viral infections were more of a recent risk marker for CFS compared to IBS (OR 2.8), with gastroenteritis a greater risk for IBS (OR 2.4).

Conclusions Both fatigue and irritable bowel syndromes share predisposing risk markers, but triggering risk markers differ. Fatigue syndromes are heterogeneous, with CFS sharing predisposing risks with IBS, suggesting a common predisposing pathophysiology.

(Received May 29 2008)

(Revised September 29 2008)

(Accepted February 26 2009)

(Online publication April 15 2009)


c1 Address for correspondence: Professor P. D. White, Centre for Psychiatry, St Bartholomew's Hospital, London EC1A 7BE, UK. (Email: