Introduction

Changes in intestinal microbiota, stress and inflammation are factors known to be relevant in the pathogenesis of pain and further symptoms in disorders of gut-brain interaction (DGBI), previously designated as functional gastrointestinal disorders (1). The same factors are also implicated in modulating cellular tight junction integrity and thereby also blood-brain and intestinal barrier permeabilities (1,2). Dietary nutrients, especially polyphenols in fruit and vegetables, can beneficially affect cellular tight junction integrity, modulate the gut microbiome and reduce pro-inflammatory effects (3).

Aims & Methods

The effects of blueberries on, 1. GI symptoms (Gastrointestinal Clinical Rating Scale: GSRS), life functioning and quality of life (Outcome Questionnaire OQ45.2), 2. circulating tight junction proteins especially relevant for the integrity of the intestinal and blood-brain barriers and, 3. stool consistency (Bristol stool scale: BSS) were prospectively examined in DGBI. Successive patients with irritable bowel syndrome or functional dyspepsia (Rome 4) received freeze-dried blueberries (equivalent to 180g of fresh blueberries) or sugar and energy-matched placebo for 6 weeks in a double-blind, randomized, cross-over study, with a washout period of 2 to 4 weeks between treatments. Serum concentrations of claudin-3, claudin-5 and zonula occludens-1 (ZO-1) were measured by ELISA and the GSRS, OQ45.2 and BSS scores were collected at baseline and after 6 weeks. The changes in protein concentrations and in GSRS, OQ45.2 and BSS scores from baseline were correlated.

Results

In 43 patients (37 females, mean age±SD 31±12yr) blueberry treatment for 6 weeks increased claudin-3 serum concentrations and improved GSRS and OQ45.2 scores significantly (see Table). Increased serum claudin-5 concentrations correlated with improved GSRS and OQ45.2 scores (Spearman’s r= -0.38, p=0.016; r= -0.36, p=0.024, resp.), while increased ZO-1 levels correlated with improved OQ45.2 scores (r= -0.32, p=0.046). There were neither significant serum concentration increases in tight junction proteins, changes in clinical outcomes nor correlations between these outcomes during placebo treatment. The median BSS was not significantly changed during either treatment, although constipation was relieved more frequently by blueberries.

Table. Outcome measures at baseline and after 6 weeks of treatment with blueberry or placebo. Within-group differences (baseline vs. week 6): *p=0.0129, **p=0.0143,***p=0.00340*

Table	Blueberry			Placebo
	Baseline	Week 6	Change (95%CI)	Baseline	Week 6	Change (95%CI)
Questionaries
Mean GSRS ± SD	37.7 ± 13.4	33.0 ± 12.9	-4.7 (-8.4 to 1.0) *	38.2 ± 11.3	36.6 ± 12.6	-1.7 (-5.2 to 1.9)
Median BSS (IQR)	3.5 (1.5)	3.5 (1.5)	0 (0 to 1.0)	4.0 (1.5)	4.0 (2.0)	0 (-0.7 to 0.5)
Median OQ-45.2 (IQR)	62.0 (15.0)	61.0 (17)	-3.0 (-5.0 to 0) **	63.0 (21)	66.0 (16)	0 (-3.0 to 3.0)
Serum tight junction protein concentrations
Median claudin-3 (IQR) (pg/ml)	76.3 (16.3)	77.2 (17.4)	2.1 (1.0 to 4.3) ***	74.5 (16.4)	72.1 (18)	0 (-1.5 to 1.2)
Median claudin-5 (IQR) (pg/ml)	38.5 (15.7)	40.3 (14.9)	1.2 (-1.1 to 4.3)	39.8 (20.2)	40.3 (15.8)	0.1 (-1.6 to 2.1)
Median Z0-1 (IQR) (pg/ml)	81.3 (25.2)	81.3 (12.5)	-1.1 (-3.9 to 1.0)	81.4 (21.3)	80.0 (14.1)	-1.7 (-6.6 to 1.5)

Conclusion

Blueberries given for 6 weeks decreased symptoms and improved measures of quality of life and life functioning scores in patients with DGBI. Concomitantly, increased serum concentrations of claudin-3, a tight junction protein important in the regulation of intestinal and other barrier tight junction integrity, were observed. Increases in circulating tight junction protein levels relevant in tightening blood-brain (claudin-5) and other (ZO-1) barrier tight junctions correlated with the improvement in symptoms.This study was supported by a grant from the US Highbush Blueberry Council.

References

(1) Martin CR, Osadchiy V, Kalani A, Mayer EA. Cell Mol Gastroenterol Hepatol. 2018;6:133-148. (2) Hanning N, Edwinson AL, Ceuleers H, et al. Therap Adv Gastroenterol. 2021;14:1756284821993586. (3) Suzuki T. Anim Sci J. 2020;91:e13357

Introduction

Blueberry ingestion resulted in significant abdominal symptom relief, improved Gastrointestinal Symptom Rating (GSRS) and quality-of-life and life functioning scores by Outcome Questionnaire (OQ 45.2) in patients with DGBI¹. It is unclear via which mechanisms blueberries exert their beneficial effect in DGBI².

Aims & Methods

We explored the associations between symptomatic responses to blueberry ingestion, faecal microbiota composition, clinical phenotypes and tests of disease mechanisms in DGBI.
Male and female patients aged 18-60 years with DGBI (irritable bowel syndrome or functional dyspepsia, Rome 4), were randomised to blueberries (30g freeze-dried powder = 180g fresh blueberries) or placebo daily for 6 weeks in a double-blind, cross-over study. GSRS and OQ-45.2 were assessed before and in week 6 of each treatment period. Responders were defined by improved GSRS or OQ-45.2. Demographics, lifestyle and symptom details were documented at baseline³. Further variables were gathered before and in week 6 of treatment: Bristol Stool Scale, breath H_2, CH₄ and symptoms after fructose 35g, cognitive tests (CANTAB®), skin fluorescence for advanced glycation end-products and serum tight junction proteins (claudin-3 and -5, zonula occludens-1). Stool microbiome analysis was performed by DNA extraction and sequencing for shotgun metagenomics. Nonmetric multidimensional scaling ordination plots based on Bray-Curtis dissimilarity were generated at the species level with clinical covariates. Spearman association of microbial species with demographics, clinical phenotype and mechanistic tests at baseline and during treatment were analysed by stratifying data into pre- and post-treatment groups, as well as responders and non-responders by GSRS and OQ-45.2.

Results

In 43 DGBI patients there were significant associations between faecal microbiota composition, clinical phenotypes and tests relating to disease mechanisms that were distinct between blueberry responders and non-responders. Examples of prominent baseline associations were breath gases after fructose with Ruminococcus sp AF41_9 in GSRS responders and with Eggerthella lenta, Lachnospiraceae bacterium AM48_27BH, Phocaeicola vulgatus, Ruminococcus callidus, Mediterraneibacter glycyrrhiznilyticus in non-responders. Cognitive skills were associated with Clostridium sp AF34_13 and Clostridiaceae bacterium Marseille_Q4149 in responders, and with Blautia glucerasea, Eggerthella lenta and Ruminococcus callidus in non-responders. Tight junction protein levels correlated with Clostridiaceae bacterium Marseille_Q4149, Anaerobutyricum hallii and Bacteroides intestinalis in responders and with Anaerostipes hadrus, Blautia faecicola, Blautia glucerasea, Clostridia bacterium UC5_1_1D1 and Ruminococcus gnavus in non-responders. During blueberry ingestion new associations between bacterial taxa and GSRS, breath gases after fructose, tight junction protein levels emerged, which were largely distinct between responder groups. Responders by OQ-45.2 showed associations between bacterial taxa, demographics and mechanistic tests both at baseline and during blueberry dosing that were largely distinct from those of GSRS responders.

Conclusion

In patients with DGBI, GI and general symptom relief with blueberry ingestion were characterised by specific, distinct associations between faecal microbiota, clinical phenotype and tests of disease mechanisms at baseline and during treatment. This first longitudinal blueberry treatment study in DGBI patients suggests an important role of the intestinal microbiota in symptom genesis warranting further study.

References

¹Wilder-Smith CH, Materna A, Olesen SS. Blueberries Improve Abdominal Symptoms, Well-Being and Functioning in Patients with Functional Gastrointestinal Disorders. Nutrients. 2023 May 20;15(10):2396.
²Kalt W, Cassidy A, Howard LR, Krikorian R, Stull AJ, Tremblay F, Zamora-Ros R. Recent Research on the Health Benefits of Blueberries and Their Anthocyanins. Adv Nutr. 2020 Mar 1;11(2):224-236.
³Wilder-Smith CH, Drewes AM, Materna A, Olesen SS. Extragastrointestinal Symptoms and Sensory Responses During Breath Tests Distinguish Patients With Functional Gastrointestinal Disorders. Clin Transl Gastroenterol. 2020 Aug;11(8):e00192.

Disclosure

This study was supported by a research grant from the US Highbush Blueberry Council.

Introduction

The antioxidant, anti-inflammatory and modulatory effects of blueberries on gut microbiota are well known¹. In patients with DGBI blueberry ingestion for 6 weeks significantly relieved abdominal symptoms and improved Gastrointestinal Symptom Rating (GSRS) and quality-of-life and life functioning scores by Outcome Questionnaire (OQ 45.2) compared to placebo². Whether changes in gut microbiota are relevant in the symptomatic relief of blueberries in DGBI is unexplored.

Aims & Methods

Male and female patients aged 18 to 60 years with DGBI (irritable bowel syndrome or functional dyspepsia, Rome 4), were randomized to double-blind blueberry (30g freeze-dried powder = 180g fresh blueberries) or placebo daily for 6 weeks, with subsequent cross-over. GSRS and OQ-45.2 scales were assessed before and in week 6 of each treatment period. Responders were defined by improved GSRS and OQ-45.2 scores. Stool microbiome analysis was performed by DNA extraction and shotgun metagenomic sequencing. Quality controlled sequences were annotated with MetaPhlAn 4. Nonmetric multidimensional scaling ordination plots based on Bray-Curtis dissimilarity were generated at the species level with clinical covariates to visualize the intra- and inter-subject variability of microbiota. ANCOM-BC2 was used to estimate the differential abundance of the prevalent species. Pairwise networks before and after intervention were constructed and the frequency difference of positive and negative associations between responders and non-responders compared. Associations of gut microbial species with outcomes were analyzed (Spearman), stratifying data into before and after intervention, as well as responder and non-responder groups.

Results

	Baseline (#p<0.05)	During blueberry ingestion (#p<0.05)
GSRS outcome (gastrointestinal)	Responders > Non-responders: 55 species; #in: Butyricimonas faecihominis, Enterocloster lavalensis, Enterocloster citroniae, Mediterraneibacter glycyrrhizinilyticus	Increased in responders & decreased in non-responders: 16 species; #in: Butyricicoccus sp AM29_23AC, Clostridia bacterium UC5_1_1D1, Clostridium sp AF34_10BH, Oscillibacter sp ER4
GSRS outcome (gastrointestinal)	Non-responders > Responders: 56 species; #in: Lachnospiraceae bacterium AM48_27BH, Clostridiaceae bacterium Marseille_Q4143, Blautia glucerasea, Clostridium sp AF34_13, Ruminococcus sp AF41_9	Decreased in responders & increased in non-responders: 8 species; #Bacteroides eggerthii
OQ 45.2 outcome (well-being)	Responders > Non-responders: 35 species: #in: Lachnospira eligens, Vescimonas coporcola	Increased in responders & decreased in non-responders: 14 species; none significant
OQ 45.2 outcome (well-being)	Non-responders > Responders: 41 species; #in: Roseburia intestinalis, Phocaeicola massiliensis	Decreased in responders & increased in non-responders: 14 species; none significant

In 43 patients, microbiome alpha diversity of the gut microbiota taxa did not change significantly between visits with either treatment and did not differ between responder groups. However, at baseline, multiple species differed in abundance between responders and non-responders for both the GSRS and OQ-45.2 outcomes (table). During blueberry ingestion there were multiple species differences between responders and non-responders for either outcome.
There were distinct association patterns in the microbial co-occurrence networks with hub taxa, especially Anaerobutyricum hallii and Ruminococcus gnavus, in responders versus non-responders at baseline and during blueberry ingestion. Negative associations between microbiota in microbial co-occurrence networks were more common in non-responders than in responders at baseline and decreased after blueberry treatment, suggesting stabilisation of the microbiome.

Conclusion

Improved GI and general quality-of-life and life-functioning scores during blueberry ingestion in DGBI are associated with distinct gut microbiota taxa and co-occurrence networks at baseline and during treatment. Confirmatory studies are required to assess causality, but these data suggest that beneficial clinical effects seen in patients with DGBI during blueberry ingestion may be linked to changes in the gut microbiome and that GI and general benefits may be effected via distinct taxa.

References

¹Kalt W, Cassidy A, Howard LR, Krikorian R, Stull AJ, Tremblay F, Zamora-Ros R. Recent Research on the Health Benefits of Blueberries and Their Anthocyanins. Adv Nutr. 2020 Mar 1;11(2):224-236.
²Wilder-Smith CH, Materna A, Olesen SS. Blueberries Improve Abdominal Symptoms, Well-Being and Functioning in Patients with Functional Gastrointestinal Disorders. Nutrients. 2023 May 20;15(10):2396.

Disclosure

This study was supported by a research grant from the US Highbush Blueberry Council.

Introduction

Fructose and fructans/fructooligosaccharides are implicated in the production of advanced glycation end products (AGE), which cause potent oxidative stress and inflammatory responses related to ageing, inflammatory and degenerative diseases (1-3). It has recently been shown that fructose intolerance is unrelated to fructose malabsorption and more probably to differences in fructose metabolism by the intestinal microbiome (4). Individual species of the intestinal microbiota can differentially either produce or metabolise AGEs, as well as ferment fructose and fructans (2). DGBI are characterised by a high prevalence of fructose and fructan intolerance, pro-inflammatory markers and changes in gut microbiota (5). The relationships between fructose intolerance, the intestinal microbiome and AGEs are unclear.

Aims & Methods

We examined the association between skin AGEs by autofluorescence (SAGE) as a validated, reproducible and non-invasive marker of metabolically long-acting AGEs (6), exhaled breath hydrogen and symptoms following fructose provocation during breath tests in 1188 patients with DGBI (Rome 4 criteria, 30% male, mean age 40.9 years, mean body mass index 23.6 kg/m²) referred to our Gastroenterology practice. A standardised breath test with fructose 35g was performed after a 24-hour low-FODMAP diet and >8-hour fast. Exhaled hydrogen concentrations and gastrointestinal symptoms (composite symptom index score, 7) were collected every 30 minutes for 5 hours. SAGE was performed with the AGE Reader® (Diagnoptics Technologies B.V., Groningen, NL) before the breath test. Lower SAGE values reflect a lower systemic pro-inflammatory AGE load.

Results

Overall, the SAGE values and hydrogen breath concentrations correlated inversely (Rho= -0.09, p=0.0022, Spearman’s rank test). Extensive fructose fermenters, defined by an increase in breath gas concentrations above baseline of >20ppm of hydrogen after fructose ingestion, showed lower SAGE values than poor metabolisers (1.85±0.56 vs. 1.92±0.55; p= 0.0221). Furthermore, patients with an increased symptom index following fructose and thereby classified as fructose intolerant (7), had significantly lower SAGE scores than fructose tolerant patients (1.84±0.55 vs. 1.96±0.57; p=0.0004).

Conclusion

Patients with DGBI and pronounced symptoms and gas production during fructose breath tests appear to have lower systemic AGEs. Metabolism by the intestinal microbiota plays an important role in both fructose intolerance and in modulating the levels of long-acting AGEs. This association may be of crucial relevance in gastrointestinal and extra-gastrointestinal dysfunction in DGBI and requires further investigation. Potential confounders, such as dietary factors, require careful consideration.

References

1. Kamphuis JBJ et al. Gastroenterology. 2020;158:652-663
2. Gugliucci A. Adv Nutr. 2017;8:54-62
3. Kamphuis JBJ et al. FASEB J. 2022;36:e22297.
4. Wilder-Smith C et al. Neurogastroenterol Motil. 2021;33::e14150
5. Spiller R. F1000Res. 2016;5:F1000
6. Almengló C et al. Methods. 2022;203:103-107
7. Wilder-Smith CH et al. Aliment Pharmacol Ther. 2013;37:1074-1083

Introduction

Fructans or fructooligosaccharides are included in the spectrum of FODMAP (fermented) sugars, which are relevant in the induction of symptoms in patients with disorders of gut-brain interaction (DGBI) and in non-coeliac gluten sensitivity (1). Fructans have been shown to induce visceral hypersensitivity, an increase in mucosal mast cells, and changes in the colonic mucosal barrier in mice, and hypersensitivity associated with an altered gut microbiome in humans (2-5). Breath tests are used in the assessment of intolerances to several FODMAPs, but the test is poorly standardised for fructans (6).

Aims & Methods

A standardised breath test with fructans (10g Orafti^®HSI) was performed afer a 24-hour low-FODMAP diet and >8-hour fast. Exhaled hydrogen and methane concentrations were measured every 30 minutes until 5h, and synchronised symptom assessments performed for 24h (composite symptom index score, SI, 7) in 600 successive male (33%) and female patients of average age 41 years referred to our gastroenterology practice with DGBI (irritable bowel syndrome and/or functional dyspepsia, Rome 4 criteria). Breath gas concentration thresholds of >20ppm and >8ppm above baseline were used for hydrogen and methane, respectively.

Results

The SI was positive in 61.2% (n=367) of patients within 24 hours of fructan ingestion. The SI peaked in the first 3 hours in 17.5% (n=105) and in the first 5 hours in 42.5% (n=255) of patients. Suprathreshold increases in hydrogen and methane concentrations within 5 hours were seen in 62.7% and 14.9% of patients, respectively. Discordant SI and breath gas results were obtained in 35.1% (hydrogen) and 57.8% (methane) of patients. A negative SI with a suprathreshold hydrogen or methane result occurred in 18.2% and 5.2%, respectively. A positive SI with a subthreshold hydrogen or methane result occurred in 16.9% and 52.6%, respectively. Suprathreshold concentrations in methane and not in hydrogen were apparent in 4.5%. Main symptoms during tests were excessive flatulence (58.8%), bloating (50.3%), abdominal fullness (49.3%), abdominal cramps (29.0%), nausea (26.7%), GORD (26.7%), diarrhoea (9%) and extra-GI symptoms (16.2%).

Conclusion

Standardised oral provocation with fructans resulted in familiar clinical symptoms in a majority of patients with DGBI, suggesting a high prevalence of fructan intolerance. Due to the slow fermentation of intestinal fructans and the associated delayed symptoms, prolonged data collection over at least 12, preferably 24 hours is recommended. The test duration of 3 hours currently commonly used in test centres is inadequate. Symptom and breath gas concentration results are often divergent, as is known from other FODMAP breath tests, and validation against clinical outcome results is required. Fructans are of interest in DGBI as the current literature suggests they have both protective as well as detrimental effects on intestinal physiology, which may be dependent on the resident microbiota.

References

1. Gry I et al. Gastroenterology 2018;154:529–539
2. Kamphuis JBJ et al. Gastroenterology 2020;158:652-663
3. Chen BR et al. World J Gastroenterol 2017;23:8321-8333
4. Kamphuis JBJ et al. FASEB J. 2022;36:e22297
5. Chumpitazi BP et al. Aliment Pharmacol Ther 2021;53:499-509
6. Fedewa A et al. Curr Gastroenterol Rep 2014;16:370
7. Wilder-Smith CH et al. Aliment Pharmacol Ther 2013;37:1074-83

Introduction

Lower gastrointestinal (GI) disorders of gut-brain interaction (DGBIs) - including irritable bowel syndrome (IBS), chronic constipation, and faecal incontinence - are highly prevalent conditions that significantly affect patients' quality of life. These disorders often present with complex and overlapping symptomatology, necessitating a nuanced understanding of each patient's unique symptom profile to provide the best chance of treatment success. Furthermore, a significant proportion have psychological comorbidities, and a history of psychological trauma is common. Consequently, eliciting a comprehensive clinical history from these patients can be challenging, and requires significant skill and sensitivity. Despite this, formal training in the clinical assessment of these patients is rare in training programs throughout the UK and Europe.

Aims & Methods

This study aimed to investigate the self-reported confidence of gastroenterologists and colorectal surgeons in obtaining comprehensive histories from patients with lower GI DGBIs, identify potential barriers to their confidence and understand their training needs. A cross-sectional survey comprising 12 questions was distributed online using the Qualtrics platform to UK gastroenterologists and colorectal surgeons between March-April 2025. The survey explored clinician demographics, confidence levels in aspects of history taking as well as perceived barriers to confidence and preferred training modalities. Confidence was rated on a 1-10 scale. Participant responses were collected anonymously.

Results

Out of 73 survey responses, 50 were included in the analysis after excluding 23 incomplete submissions. The cohort comprised 29 (58%) colorectal surgeons and 21 (42%) gastroenterologists, primarily consisting of resident doctors (93%) with a minority being post-CCT participants (7%).
Overall, reported confidence in history taking increased with training progression, demonstrating a median self-reported confidence level of 7 during specialty training and 10 at the post-CCT/attending level (T-test, p<0. 0001). Specific confidence ratings for ‘trauma/abuse history’ and ‘psychological co-morbidities’ were notably lower, with medians of 5 and 6, respectively, highlighting significant gaps (ANOVA, p<0. 0001) compared to other areas such as ‘toileting habits’ and ‘pain history’.
The major barriers to confidence included a lack of training (58%) and experience (50%), followed by concerns regarding the management of sensitive information (26%) and difficulties in discussing these topics with patients from different genders/social backgrounds (18%). Less than half (38%) reported receiving any form of training in history taking, and among those, only 47% received training from their institution. Notably, 83% of participants expressed a desire for additional training, with the majority (76%) preferring to receive this from their training providers.

Conclusion

As GI clinicians progress through their medical career, their confidence in conducting histories from patients with lower GI DGBIs increases. However, confidence is lacking when enquiring about psychological factors, in particular a history of trauma or abuse. Enhancing the competence of doctors in this area early is likely to foster confidence and improve patient outcomes in this field.

Introduction

Population-based surveys have demonstrated substantial overlap of DGBI across multiple gastrointestinal (GI) regions and that this overlap is associated with increased health impairment. Comprehensive assessments of this overlap in patients with IBS are lacking, and the link with pathophysiology is not understood. In addition, IBS patients also frequently report overlapping non-GI comorbidities (somatic symptoms disorder , depression and anxiety) .The interaction between overlapping DGBI and non-GI comorbidities in IBS, and the impact of this interaction needs to be further investigated.

Aims & Methods

We included IBS patients with completed ROME II, III or IV questionnaires to assess overlapping DGBI in other anatomical GI regions (esophageal, gastroduodenal, anorectal). Patients completed validated questionnaires to measure the severity of GI (Gastrointestinal Symptom Rating Scale for IBS (GSRS-IBS)) and psychological (Hospital Anxiety and Depression Scale (HADS)) symptoms, IBS-specific quality of life (QOL) (IBS QOL), GI symptom-specific anxiety (Visceral Sensitivity Index (VSI)), and somatic symptoms (Patient Health Questionnaire-15 (PHQ-15) and Symptom Checklist-90 (SCL90)). Overlap of non-GI comorbidites (somatic symptom disorder, depression and anxiety) were assessed using suggested cut-off levels on PHQ, SCL-90 and HADS. Oro-anal transit time (OATT) was measured with radiopaque markers, and rectal sensitivity with balloon distensions using a barostat. GI symptoms following a Lactulose Nutrient Challenge Test (LNCT) were also recorded as a measurement of sensitivity to microbial fermentation and nutrients.

Results

We included 688 patients with IBS (70.5% female, mean age 37.3 ± 12.5 years; IBS-C 29.7 %, IBS-D 34.6 %, IBS-M 24.7%, and IBS-U 11.0%.). Overall, 68.3% of IBS patients had overlapping DGBI in other anatomical GI regions; one region: 39.4%, two regions: 23.3%, three regions: 5.7%. An overlapping esophageal DGBI was seen in 26.2%, a gastroduodenal DGBI in 31.6%, and anorectal DGBI in 38.1%. The prevalence of overlapping somatic symptom disorder in IBS was 53.8%, while depression and anxiety overlap was seen in 32.2% and 50.9% of the IBS patients. A higher number of non-GI comorbidities was associated with a greater number of overlapping DGBI in IBS (p<0.01).
With increasing number of overlapping DGBI diagnoses and non-GI comorbidities in IBS, there was a gradual increase in the severity of GI and psychological symptoms, as well as a gradual decrease in QOL (Table 1). In addition, with increasing number of overlapping diagnoses, a gradual increase in visceral sensitivity (reduction in rectal discomfort threshold and increased discomfort during LNCT) was seen, but no links with abnormal OATT, age or body mass index were noted.

Table 1: Comparison of background, symptom severity and physiological parameters among different overlapping status in patients with IBS.
	IBS only	IBS plus one comorbidity	IBS plus two comorbidities	IBS plus three comorbidities	IBS plus four comorbidities	IBS plus five comorbidities	p	η2
Age (years, mean (SD))	34.1 (10.9)	34.6 (11.5)	34.5 (10.9)	36.8 (12.8)	35.3 (11.3)	36.2 (12.5)	0.64	0.01
Sex (female (%))	32 (54.2)	60 (64.5)	85 (81.7)	65 (67.7)	50 (73.5)	51 (83.6)	<0.01
GSRS-IBS total score (mean (SD))	3.0 (0.8)	3.3 (0.7)	3.6 (0.8)	3.9 (0.8)	4.3 (0.8)	4.4 (0.9)	<0.01	0.25
IBSQOL average score (mean (SD))	70.4 (15.1)	64.4 (16.6)	61.5 (15.7)	57.6 (17.4)	51.4 (16.1)	43.9 (16.4)	<0.01	0.18
VSI score (mean (SD))	41.9 (17.8)	48.1 (18.8)	44.0 (16.0)	46.9 (15.7)	51.1 (13.6)	53.7 (14.8)	<0.01	0.05
Abnormal OATT (n (%))	19 (35.2)	21 (24.1)	26 (26.8)	28 (30.4)	17 (27.4)	11 (20.0)	0.54
Rectal sensitivity (discomfort threshold, z-score, mean (SD))	0.3 (1.0)	0.0 (0.9)	-0.1 (0.9)	-0.2 (0.9)	-0.3 (0.8)	-0.3 (0.7)	<0.01	0.05
LNCT (discomfort AUC, mean (SD))	1209.8 (835.3)	1345.2 (776.4)	1740.9 (990.1)	1674.9 (932.4)	2298.5 (1161.5)	2430.5 (1015.3)	<0.01	0.17

Conclusion

Overlapping DGBI diagnoses and non-GI comorbidities are common among IBS patients. This overlap has an impact on both GI and non-GI symptoms, as well as a link with GI sensitivity. Assessment of overlapping DGBI and non-GI comorbidites seems to be of importance to optimize clinical management in patients with IBS.