Risk factors for irritable bowel syndrome: Role of analgesics and food sensitivities

OBJECTIVE: Symptoms of irritable bowel syndrome (IBS) are reported by 10% of the general population; however, evaluation of traditional risk factors has not provided any insight into the pathogenesis of this condition. The objective of this study was to identify additional risk factors for irritable bowel syndrome. METHODS: A valid self-report questionnaire that records the gastrointestinal (GI) symptoms required for a diagnosis of IBS, self-reported measures of potential risk factors, and a psychosomatic symptom checklist was mailed to an age-and gender-stratified random sample of Olmsted County, Minnesota residents aged 30-64 yr. A logistic regression model that adjusted for age, gender, and psychosomatic symptom score was used to identify factors significantly associated with IBS. RESULTS: A total of 643 (72%) of 892 eligible subjects returned the survey. IBS symptoms were reported by 12% of the respondents. IBS was significantly associated with use of analgesics (acetaminophen, aspirin, or nonaspirin nonsteroidal antiinflammatory drugs) for reasons other than IBS, reporting a food allergy or sensitivity, and ratings of somatic symptoms. No association was detected for age, gender, body mass index, smoking history, alcohol use, educational level, exposure to pets in the household, or water supply. Among subjects reporting the use of just one type of analgesic, IBS was associated with acetaminophen but not aspirin or nonaspirin nonsteroidal antiinflammatory drugs used alone. The odds of having IBS were higher among subjects reporting more reasons for taking analgesics and intolerance to a higher number of foods. CONCLUSIONS: IBS is significantly associated with analgesic use. However, this is confounded by other somatic pain complaints. IBS symptoms are associated with the reporting of many food allergies or sensitivities. The role of food-induced symptoms in IBS requires further investigation.