The impact of atopic disease on the risk of post-infectious fatigue and irritable bowel syndrome 3 years after Giardia infection. A historic cohort study

Abstract Objective. To investigate whether atopic disease influences the prevalence of irritable bowel syndrome (IBS) and chronic fatigue (CF) after giardiasis. Methods. A questionnaire was sent to all confirmed cases of giardiasis after a Norwegian outbreak, with response rate of 65.3% (817/1252). Controls were randomly selected matched on age and sex, with response rate of 31.4% (1128/3598). Associations were evaluated by use of logistic regression analyses. Results. In the Giardia exposed group, 47.8% of those with asthma had IBS compared with 45.3% in those without asthma (p = 0.662). For controls, corresponding percentages were 23.9% and 12.2% (p < 0.001). Among those with asthma, the adjusted relative risk (RR) for IBS was 2.03 (95% confidence interval (CI): 1.45, 2.62) for the exposed group compared with controls. In those without asthma, the corresponding RR was 3.80 (95% CI: 3.30, 4.32). In the exposed group, 51.5% of those with asthma had CF compared with 44.9% in those without asthma (p = 0.218...