Introduction
Irritable bowel syndrome (IBS) and functional dyspepsia (FD) are common disorders of gut-brain interaction (DGBI), and bloating and visible abdominal distension are common symptoms among individuals with IBS and/or FD. Bloating refers to a subjective sensation of tension or pressure in the abdomen, which may or may not be reported together with visible abdominal distension. The underlying pathophysiological mechanisms may differ, with bloating suggested to be more related to hypersensitivity and visible abdominal distension to altered motility. The prevalence of these two symptoms in IBS and FD, especially as distinct symptoms, is not well known.
Aims & Methods
The aim was to investigate the link between bloating and distension with IBS and FD. Therefore, we performed a population-based internet survey of adults in the US, UK, and Mexico, including Rome IV IBS and FD diagnostic questions, somatization (PHQ-12), and psychological distress (PHQ-4). Four groups were created: those meeting the Rome IV criteria for IBS only, FD only, both IBS+FD, and a reference group including individuals without IBS, FD and organic diagnoses that could result in IBS- or FD-like symptoms. Within each group, we identified individuals who reported ≥weekly bloating alone (B), ≥weekly visible abdominal distension alone (D), ≥weekly combined B+D, or neither of both. The relationship between B, D and B+D in those with IBS and/or FD vs. the reference group was investigated using logistic regression models.
Results
The analysis included 5,448 participants (49.7% female; mean age 46.5 years, range 18-99), with 131 meeting criteria for IBS only, 360 for FD only, 217 for IBS+FD and 4,740 for the reference group. A larger proportion of individuals with IBS only (64.9%), FD only (50.6%), and especially those with IBS+FD (88.5%) reported bloating and/or visible abdominal distension compared to the reference group (13.7%). In the IBS only group, 16.0% reported bloating alone, 8.4% visible abdominal distension alone, and 40.5% combined bloating and visible abdominal distension. In the FD only group this was 12.8% (B), 8.9% (D), and 28.9% (B+D), and in the IBS+FD group 18.9% (B), 8.3% (D), and 61.3% (B+D), respectively. Reporting bloating alone or combined bloating and visible abdominal distension was strongly linked to fulfilling criteria for IBS only, FD only, and concomitant IBS+FD vs. the reference group, with weaker links for visible abdominal distension in the absence of bloating (Table). After adjusting for age, sex, BMI, psychological distress and somatization, the links persisted. The strongest association was observed between combined bloating and visible abdominal distension (vs. neither) and concomitant IBS+FD (vs. the reference group); adjusted odds ratio 28.6 [95%CI 17.6-46.6].
| IBS without FD vs. reference group Crude OR [95%] | FD without IBS vs. reference group Crude OR [95%CI] | IBS+FD vs. reference group Crude OR [95%CI] |
| Bloating alonea | 13.7 [8.0-23.6] | 7.8 [5.4-11.2] | 49.3 [29.1-83.4] |
| Visible abdominal distension alonea | 5.0 [2.5-9.7] | 3.7 [2.5-5.6] | 14.9 [8.0-27.9] |
| Combined bloating and visible abdominal distensiona | 14.8 [9.8-22.3] | 7.5 [5.8-9.8] | 68.4 [44.0-106.5] |
| IBS without FD vs. reference group Adjusted OR [95%] b | FD without IBS vs. reference group Adjusted OR [95%] b | IBS+FD vs. reference group Adjusted OR [95%] b |
| Bloating alonea | 8.5 [4.6-15.5] | 4.8 [3.1-7.2] | 25.6 [14.5-45.1] |
| Visible abdominal distension alonea | 3.9 [1.9-7.9] | 2.9 [1.9-4.5] | 9.3 [4.9-17.9] |
| Combined bloating and visible abdominal distensiona | 8.4 [5.1-13.6] | 4.4 [3.2-6.0] | 28.6 [17.6-46.6] |
Table. Link between bloating and/or visible abdominal distension and IBS and FD a ≥weekly bloating and/or visible distension vs. <weekly bloating and distension or neither of both. b odds ratio based on logistic regression models, adjusted for age, sex, BMI, psychological distress (PHQ-4), and somatization (PHQ-12). |
Conclusion
Bloating and visible abdominal distension as distinct and overlapping symptoms are strongly linked to IBS, FD, and concomitant IBS+FD in the general population. Assessing bloating and visible abdominal distension as separate symptoms may be important to enable individualized treatment for individuals with IBS and FD.