Background: increasing body mass index (BMI) is a risk factor for GERD but little is known about this association in the irritable bowel syndrome (IBS).
Aims: to determine the presence of heartburn and other related symptoms in relation with BMI in IBS.
Methods: volunteers (n = 483) answered the Rome II-Modular Questionnaire, and were divided into IBS and non-IBS (controls) groups. The frequency of heartburn, chest pain, epigastric pain, nausea, vomiting and belching was compared between the groups in the study sample and within three BMI categories.
Results: the IBS (23.7%) and controls (76.3%) were similar in gender (females: 68.1%), age (32.2 +/- 12.7 years), and BMI (25.4 +/- 4.4). Raw associations analysis showed that heartburn: OR: 1.62 (95%CI: 1.04-2.53), chest pain: 1.77 (1.13-2.77), epigastric pain: 1.75 (1.03-2.98) and nausea: 2.45 (1.10-5.32) were more frequent in IBS vs. controls. Meanwhile, according to BMI, in those with obesity, heartburn was more frequent in IBS and among those with overweight, epigastric pain and nausea were also more frequent in IBS. However, in an adjusted log linear model, no significant interaction was found between BMI and any other studied symptom and heartburn was found to be independent of IBS: 1,4 (0.9, 4.7). Finally, a logistic regression model found no interaction between BMI and the presence of heartburn or IBS.
Conclusions: while heartburn and other reflux-related symptoms are more frequent in IBS than in controls, these associations are independent of BMI.