Lauren Killian1 and Soo-Yeun Lee1,2
1Division of Nutritional Sciences, University of Illinois at Urbana-Champaign
2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign
Background: Gastrointestinal (GI) symptoms are reported in a large proportion of endurance athletes, with many similarities in symptom type and distribution to irritable bowel symptom (IBS) patients. While many studies report athlete GI symptoms, to the best of our knowledge, no studies have examined actual IBS diagnoses or fit to IBS diagnostic criteria among this group.
Objective: The objective of this study was to develop and validate a questionnaire to assess actual IBS diagnoses by a medical professional or fit to either Manning or Rome III diagnostic criteria for IBS among endurance athletes.
Methods: A 92 item Endurance Athlete Questionnaire was developed which incorporated portions of an existing athlete GI symptom questionnaire, the Manning criteria and the Rome III Diagnostic Questionnaire for Adult Functional GI Disorders focusing on functional bowel disorders. Other important factors included gastrointestinal symptoms, nutritional habits and symptom mitigation strategies. The questionnaire was targeted at endurance athletes who will have completed at least one of the following events within 2015: marathon, ultra-marathon, half-distance triathlon, or full-distance triathlon. Content validity was established by expert reviewers and face validity was evaluated by endurance athletes who had completed at least one of the qualifying events within the last three years. Test-retest reliability was assessed with a group of target athletes recruited through local running and triathlon clubs as well as social media.
Results: Six expert reviewers evaluated content validity, of which three were gastroenterologists and three were Registered Dietitians specializing in working with athletes. Reviewers suggested slight modifications in wording, but no major problems were identified. Face validity was evaluated by nine endurance athletes. All athletes understood the items and a few minor modifications in wording were suggested. Athletes also recommended the addition of a question on tobacco and alcohol use. The questionnaire was administered to target population athletes (n=55) on two occasions, separated by 1-2 weeks. Analysis was performed on the applicable item scores of 51 subjects (4 subjects reported a major GI issue within the last week on only one questionnaire). The Pearson correlation coefficient for the test-retest was significant at 0.882 (p<0.001).
Conclusion: The Endurance Athlete Questionnaire had good content and face validity and proved to be a reliable measure of GI symptoms and IBS diagnostic criteria among endurance athletes. This questionnaire is needed to evaluate diagnosed and undiagnosed IBS in endurance athletes as well as symptomatic athletes who do not fit the diagnostic criteria. This will aid in future research examining nutritional modifications that may help mitigate athlete GI symptoms.