Irritable bowel syndrome and chronic fatigue 6 years after giardia infection: a controlled prospective cohort study.
BACKGROUND
Functional gastrointestinal disorders and fatigue may follow acute infections. This study aimed to estimate the persistence, prevalence, and risk of irritable bowel syndrome and chronic fatigue 6 years after Giardia infection.


METHODS
We performed a controlled prospective study of a cohort of 1252 individuals who had laboratory-confirmed Giardia infection during a waterborne outbreak in 2004. In total, 748 cohort cases (exposed) and 878 matched controls responded to a postal questionnaire 6 years later (in 2010). Responses were compared to data from the same cohort 3 years before (in 2007).


RESULTS
The prevalences of irritable bowel syndrome (39.4%) by Rome III criteria and chronic fatigue (30.8%) in the exposed group 6 years after giardiasis were significantly elevated compared with controls, with adjusted relative risks (RRs) of 3.4 (95% confidence interval [CI], 2.9-3.9) and 2.9 (95% CI, 2.3-3.4), respectively. In the exposed group, the prevalence of irritable bowel syndrome decreased by 6.7% (RR, 0.85 [95% CI, .77-.93]), whereas the prevalence of chronic fatigue decreased by 15.3% from 3 to 6 years after Giardia infection (RR, 0.69 [95% CI, .62-.77]). Giardia exposure was a significant risk factor for persistence of both conditions, and increasing age was a risk factor for persisting chronic fatigue.


CONCLUSIONS
Giardia infection in a nonendemic setting is associated with an increased risk for irritable bowel syndrome and chronic fatigue 6 years later. The prevalences of both conditions decrease over time, indicating that this intestinal protozoan parasite may elicit very long-term, but slowly self-limiting, complications.
['Hanevik|Kurt|K|', 'Wensaas|Knut-Arne|KA|', 'Rortveit|Guri|G|', 'Eide|Geir Egil|GE|', 'Mørch|Kristine|K|', 'Langeland|Nina|N|']
D000293:Adolescent D000328:Adult D000368:Aged D000369:Aged, 80 and over D016022:Case-Control Studies D002648:Child D015673:Fatigue Syndrome, Chronic D005260:Female D005873:Giardiasis D006801:Humans D043183:Irritable Bowel Syndrome D008297:Male D008875:Middle Aged D009664:Norway D016017:Odds Ratio D015995:Prevalence D011446:Prospective Studies D012306:Risk D011795:Surveys and Questionnaires D055815:Young Adult
irritable bowel syndrome chronic fatigue Giardia postinfectious