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). For controls, corresponding percentages were 19.3% and 10.7% (p = 0.004). Among those with asthma, the adjusted RR for CF was 2.73 (95% CI: 1.98, 3.45) for the exposed compared with controls. In those without asthma, the corresponding RR for CF was 4.25 (95% CI: 3.66, 4.85). Conclusion. For the exposed, having asthma or allergy did not increase the outcome of IBS or CF. For the control group, having an atopic disease made a substantial risk difference, with significantly more IBS and CF.

Key Words::

• allergy
• asthma
• chronic fatigue
• Giardia lamblia
• irritable bowel syndrome

Acknowledgements

The authors would like to thank Trygve Hausken, Per Olav Vandvik, Jon Håvard Loge and Cecilie Svanes for valuable input regarding the selection of study variables and design of the questionnaire. Funding: An open grant from the Municipality of Bergen covered the cost for production and mailing of the questionnaire and for the services delivered by Statistics Norway. All researchers are independent from the sponsors. The sponsors had no role in study design, in collection, analysis and interpretation of data, or in writing or deciding to submit the manuscript.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.