Vendel Ailin Kristensen

• Lindstrøm, Jonas Christoffer; Gjerdrum, Hilde Synnøve Vollan; Brynildsrud, Ola Brønstad; Tannæs, Tone Møller; Kristoffersen, Anja Bråthen & Ricanek, Petr [Show all 17 contributors for this article] (2026). Exploring alterations in the gut resistome in medically treated inflammatory bowel disease patients. BMC Microbiology. 26, p. 1–13. doi: 10.1186/s12866-026-05101-9. Full text in Research Archive
• Berset, Ingrid Prytz; Lerang, Frode; Moum, Bjørn Allan; Jahnsen, Jørgen; Grimstad, Tore Bjørn & Kristensen, Vendel Ailin [Show all 26 contributors for this article] (2026). Anti-TNF withdrawal or long-term treatment in ulcerative colitis (BIOSTOP): a multicentre open label, randomized controlled trial. Journal of Crohn's and Colitis. ISSN 1873-9946. 20(8). doi: 10.1093/ecco-jcc/jjag110. Full text in Research Archive Show summary

  Background and Aims: Anti-tumour necrosis factor (anti-TNF) treatment is effective in ulcerative colitis (UC). Optimal treatment duration is uncertain. This trial studies outcome after anti-TNF withdrawal compared to maintenance treatment in UC. Methods: In this prospective, multicentre, randomized, controlled, open-label non-inferiority study, patients in deep clinical, biochemical and endoscopic remission were randomized 1:1 to anti-TNF withdrawal or maintenance treatment. Primary endpoint was endoscopically confirmed remission (Mayo Endoscopic Score 0 or 1) after two years, including UC flares treated with anti-TNF, or non-biologic agents. Secondary endpoints were clinical remission, UC flare rate and treatment response. We needed 170 participants to show non-inferiority with a 15% margin. Results: Between June 2017 and December 2021, 172 UC patients from 19 Norwegian hospitals were randomized; 86 in each group. The per-protocol population was 163 patients. Nine patients were excluded due to consent withdrawal or protocol violation. Eighty percent (66/82) of anti-TNF withdrawal and 96% (78/81) of maintenance patients were in endoscopic remission after 2 years. UC flares occurred in 52% (45/86) of withdrawal and 12% (10/86) of maintenance patients. Anti-TNF retreatment was successful in 74% (20/27). Conclusion: Two years after anti-TNF withdrawal in UC patients in deep remission, endoscopically confirmed remission rate was significantly lower compared to maintenance treatment. Non-inferiority could not be proven. UC flare rate after anti-TNF withdrawal was high, but most were successfully treated. The majority did not receive AZA. Importantly, 48% of anti-TNF withdrawal patients remained in steroid-free remission. No significant predictors for UC activity after anti-TNF withdrawal were identified.

• Hansen, Simen Hyll; Bhattacharjee, Niharika; Hu, Chang; Maseng, Maria Gjerstad; Grannö, Olle & Bang, Corinna [Show all 20 contributors for this article] (2026). Bacterial clusters are associated with the risk of severe disease progression in inflammatory bowel disease irrespective of conventional disease categories. Microbiome Research Reports. 5(1). doi: 10.20517/mrr.2025.96. Full text in Research Archive Show summary

  Background: Inflammatory bowel diseases (IBDs) are complex conditions marked by chronic inflammation in the gastrointestinal tract. Traditional classification separates IBD into Crohn’s disease and ulcerative colitis, but this division may not fully capture disease heterogeneity. Here, we examine whether microbiome-driven subtyping can describe novel clinical IBD phenotypes. To achieve this, we applied unsupervised clustering to fecal microbiota profiles from the population-based Inflammatory Bowel Disease in South-Eastern Norway III (IBSEN III) cohort. Methods: A Gaussian Mixture Model (GMM) was used to cluster participants with IBD based on microbiome composition and examine associations between clusters and clinical outcomes, including inflammatory markers and disease severity during the first year after inclusion. Results: Three microbiome-based clusters were identified: CLO (dominated by Clostridia UCG-014), ALF (Agathobacter, Lachnoclostridium, and Faecalibacterium), and RUM (Ruminococcus gnavus). Participants in the RUM cluster had a higher risk of future severe disease than those in the CLO cluster, even among participants with remission-to-mild disease at inclusion (21% vs. 6%, P < 0.00001). This association could not be explained by antibiotic use or baseline disease severity. Cluster membership alone performed comparably to fecal calprotectin in distinguishing severe disease, and a combined model significantly improved accuracy (P < 0.0001). Conclusion: Our findings demonstrate a connection between microbiome composition and the risk of severe disease development, which is partly independent of inflammation levels at the time of sampling. Microbiome-informed subgrouping could lead to more personalized treatment strategies. Further validation is needed to determine the clinical utility of these clusters.

• Maseng, Maria Gjerstad; Hansen, Simen Hyll; Grännö, Olle; Bang, Corinna; Lund, Charlotte & Huppertz-Hauss, Gert [Show all 22 contributors for this article] (2026). Disentangling the gut microbiome and inflammation in inflammatory bowel diseases: longitudinal observations from the IBSEN III study. Inflammatory Bowel Diseases. ISSN 1078-0998. doi: 10.1093/ibd/izag051. Full text in Research Archive Show summary

  Background and Aim Despite the well-established involvement of the gut microbiome in inflammatory bowel disease (IBD), less is known about how the gut microbiome changes over time and how it varies with clinical disease activity and fecal calprotectin (f-calprotectin). To address this gap, we utilized samples from the population-based inception cohort of the Inflammatory Bowel Disease in South-Eastern Norway III (IBSEN III) study. Methods Data and stool samples from study participants with IBD and symptomatic controls were collected at diagnosis and after 3, 6, and 12 months. Microbiome profiling of stool samples was performed targeting the V3-V4 region of the 16S rRNA gene, and a consensus-based approach of mixed models was employed for the longitudinal microbiome analysis. Results We included 1251 samples from 744 patients with ulcerative colitis, 618 samples from 356 patients with Crohn’ s disease and 266 samples from 164 symptomatic non-IBD controls. In the IBD population, we observed that levels of f-calprotectin decreased over time, as did the patient-reported disease activity (P < .001). Distinct changes in the gut microbiome of IBD patients were observed throughout the first year, such as increased alpha diversity (P < .001) and significant taxonomic changes. Notably, there was no covariation between the changes in alpha diversity and f-calprotectin or symptom score. Conclusion The gut microbiome during the first year after IBD diagnosis showed changes that paralleled inflammation and clinical disease activity, albeit without covariation, suggesting that there may be a disease-driving impact of gut microbiome independent of inflammation and inflammation-driven symptoms.

• Bergsmark, Camilla; Kristensen, Vendel Ailin; Sjåmo, Maren B.; Høivik, Marte Lie & Anisdahl, Karoline (2026). Therapeutic drug monitoring in inflammatory bowel disease patients switching from intravenous to subcutaneous infliximab: insights from a prospective real-world study. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. doi: 10.1080/00365521.2026.2645083. Full text in Research Archive
• Mathisen, Charlotte Bache-Wiig; Nyström, Niklas; Bazov, Igor; Øyås, Ove; Zucknick, Manuela & Andersen, Svend [Show all 23 contributors for this article] (2026). A novel diagnostic serum protein signature for pediatric inflammatory bowel disease. Journal of Pediatric Gastroenterology and Nutrition - JPGN. ISSN 0277-2116. doi: 10.1002/jpn3.70379. Full text in Research Archive Show summary

  Abstract Objectives Diagnostic delay is common in pediatric inflammatory bowel disease (PIBD), and fecal calprotectin (FCP) is often limited by challenges with sample collection. Therefore, we aimed to identify and validate a blood‐based diagnostic protein signature of PIBD. Methods Proteins were analyzed using proximity extension assay in plasma samples from treatment‐naïve pediatric patients in a Swedish inception cohort referred for suspected inflammatory bowel disease (IBD) and validated in an independent Norwegian population‐based pediatric inception cohort. Diagnostic performance was estimated by the area under the curve (AUC) with 95% confidence intervals (CIs). Results The discovery cohort included 58 patients with PIBD and 36 symptomatic controls without evidence of IBD, while the validation cohort consisted of 79 patients with PIBD and 37 symptomatic controls. In total, 154 proteins were examined. Univariable analyses identified 26 differentially regulated proteins for PIBD versus symptomatic controls in the discovery cohort ( q  < 0.05), whereas 29 proteins were differentially regulated in the validation cohort. Using regularized logistic regression, we identified a diagnostic model of 31 proteins that differentiated PIBD from symptomatic controls in the discovery cohort (AUC = 0.83; 95% CI: 0.74–0.90). The protein signature was further reduced to a clinically relevant biomarker consisting of high‐sensitivity C‐reactive protein (hsCRP) and seven other proteins with diagnostic capacity (AUC = 0.85, 95% CI: 0.78–0.92) outperforming hsCRP in the validation cohort ( p  = 0.006). Conclusions We identified and validated a blood‐based protein signature for PIBD with superior diagnostic performance compared to hsCRP. Given the challenges of fecal sample collection, further assay development may enable integration of these biomarkers into diagnostic pathways for PIBD. Trial Registration ClinicalTrials.gov identifier: NCT02727959.

• Johansen, Ingunn; Hagen, Milada; Løkkeberg, Stine Eileen Torp; Aabrekk, Tone Bergene; Asak, Øyvind & Bengtson, May-Bente [Show all 22 contributors for this article] (2026). Anxiety and depression in newly diagnosed patients with inflammatory bowel disease (the IBSEN III study) compared with the general population in Norway. Journal of Crohn's and Colitis. ISSN 1873-9946. 20(3). doi: 10.1093/ecco-jcc/jjag021. Full text in Research Archive Show summary

  Background and Aims: Symptoms of anxiety and depression are common in inflammatory bowel disease (IBD); the aim of this study was to assess the proportion of anxiety and depression in patients newly diagnosed with IBD, compare the rates with the Norwegian general population (NGP), and examine associations with selected sociodemographic, psychological, and disease-related factors. Methods: This prospective cohort study included newly diagnosed patients with IBD, and data from the HUNT4 survey of the NGP. Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale. Crude statistical comparisons were performed using t-tests, Mann–Whitney U test, chi-square tests, or Fisher’s exact tests. Adjusted associations were modeled using multiple robust linear regression and multiple logistic regression. Results: In total, 938/1562 (62.1%) patients with IBD completed the Hospital Anxiety and Depression Scale (Crohn’s disease [CD]: n = 297, ulcerative colitis [UC]: n = 641). The proportion of anxiety was 37.4% in CD and 32.1% in UC, while depression was reported by 21.9% and 16.8%, respectively. Both rates were significantly higher than those observed in the NGP (17.5% for anxiety and 9.4% for depression). Compared with the NGP, males with CD had significantly higher levels of anxiety and depression, males with UC had elevated anxiety only, while females with CD and UC showed increased anxiety and depression. Both substantial fatigue and general self-efficacy were significantly associated with anxiety and depression in IBD. Conclusions: Newly diagnosed patients with IBD experienced significant psychological challenges compared with the NGP. Early identification of anxiety and depression may enable targeted interventions.

• Mahdy, Aya K. H.; ElAbd, Hesham; Kokubun, Érika Endo; Kriukova, Valeriia; Pesesky, Mitchell & May, Damon H. [Show all 24 contributors for this article] (2026). Multi-centered T cell repertoire profiling identifies alterations in the immune repertoire of individuals with inflammatory bowel disease across different disease stages. Genome Medicine. 18. doi: 10.1186/s13073-025-01575-w. Full text in Research Archive Show summary

  Abstract Background Inflammatory bowel disease (IBD) is an incurable immune-mediated inflammatory disease, affecting the gut with a high rate of primary- and secondary- loss-of-response to therapy. By investigating the T cell receptor repertoire of individuals with IBD, novel therapeutic and preventive strategies can be identified, and a better understanding of IBD can be obtained. Methods To identify and validate T cell clonotypes implicated in the pathogenesis of IBD, we profiled the T cell receptor alpha (TRA) repertoire of three cohorts containing treatment-naive, treated individuals, and individuals living with the disease for >20 years, resulting in an exhaustive dataset containing the TRA repertoire of 1,732 individuals. Results Using the generated datasets, we were able to replicate previous findings describing the expansion of Crohn’s-associated invariant T (CAIT) cells in individuals with Crohn’s disease (CD) in the three cohorts. Using a hypothesis-free statistical testing framework, we identified clonotypes that were associated with the disease at its different stages, e.g., at the time of diagnosis and decades post-diagnosis. By conducting a meta-analysis across the three cohorts, we were able to identify a set of clonotypes that were associated with the disease regardless of its stage. We validated our findings in a previously published independent test dataset from a German cohort, showing the robustness of the identified clonotypes. Conclusions The identified clonotypes are novel therapeutic targets to treat IBD, for example, through targeted depletion. By identifying antigens recognized by these T cells, a better understanding of the etiopathology of IBD, particularly CD, can be obtained.

• Holten, Kristina Ingeborg Aass; Bernklev, Tomm; Opheim, Randi; Olsen, Bjørn Christian Elias Grova; Johansen, Ingunn & Strande, Vibeke [Show all 19 contributors for this article] (2026). Fatigue Trajectory During the First Year of an Inflammatory Bowel Disease Diagnosis, Results from the IBSEN III study. Digestive Diseases and Sciences. ISSN 0163-2116. 71, p. 2476–2487. doi: 10.1007/s10620-025-09661-0. Full text in Research Archive Show summary

  Background: Fatigue is common in Crohn's disease (CD) and ulcerative colitis (UC), but the pathogenesis remains poorly understood. Aims: This study aimed to assess changes in fatigue prevalence during the first year after diagnosis and examine the association between disease course and substantial fatigue (SF) at the 1-year follow-up. Methods: Adults with newly diagnosed CD or UC were recruited from the population-based IBSEN III cohort. Fatigue was assessed at diagnosis and the 1-year follow-up using the Fatigue Questionnaire. Associations between SF at the 1-year follow-up and disease-related factors were quantified using multivariate logistic regression adjusted for sex, age and comorbidities. Results: In total, 596 patients were included (CD: 196, UC: 400). SF was present at both baseline and after one year of disease for 46.9% (n = 92/196) and 40.5% (n = 162/400) of patients with CD and UC, respectively. In CD, development of endoscopically non-passable stricture and/or surgically treated stricture within first year of disease (OR = 4.52, 95%CI [1.61;12.68]), self-reported flares since diagnosis (OR = 2.55, 95%CI [1.26;5.16]), female sex (OR = 3.12, 95%CI [1.53;6.37]) and comorbidities (OR = 4.05, 95%CI [1.89;8.69]) were independently associated with SF at the 1-year follow-up. In UC, SF was associated with current biological treatment (OR = 5.14, 95%CI [1.56;16.96]), increasing Mayo endoscopic score at the 1-year follow-up (OR = 1.54, 95%CI [1.01;2.35]), self-reported flares since diagnosis (OR = 2.66, 95%CI [1.24;5.72]) and female sex (OR = 2.20, 95%CI [1.06;4.57]). Conclusions: Fatigue frequently persists through the first year after IBD diagnosis. Clinical factors reflecting a more severe disease course were associated with SF one year after diagnosis in both CD and UC.

• Mahdy, Aya K. H.; Schöpfel, Valentina; Huppertz-Hauss, Gert; Perminow, Gøri Margrete; Tran, Florian & Bang, Corinna [Show all 17 contributors for this article] (2025). Simultaneous profiling of the blood and gut T and B cell repertoires in Crohn’s disease and symptomatic controls illustrates tissue-specific alterations in the immune repertoire of individuals with Crohn’s disease. Frontiers in Immunology. 16. doi: 10.3389/fimmu.2025.1638522. Full text in Research Archive Show summary

  Introduction Crohn’s disease (CD) is a clinical subset of inflammatory bowel disease that is characterized by patchy transmural inflammation across the gastrointestinal tract. Although the exact etiology remains unknown, recent findings suggest that it is a complex multifactorial disease with contributions from the host genetics and environmental factors such as the microbiome. We have previously shown that the T cell repertoire of individuals with CD harbors a group of highly expanded T cells which hints toward an antigen-mediated pathology. Methods We simultaneously profiled the αβ and γδ T cell repertoire in addition to the B cell repertoire of both the blood and the colonic mucosa of 27 treatment-naïve individuals with CD and 27 age-matched symptomatic controls. Results Regardless of disease status, we observed multiple physiological differences between the immune repertoire of blood and colonic mucosa. Additionally, by comparing the repertoire of individuals with CD relative to controls, we observed different alterations that were only detected in the blood or colonic mucosa. These include a depletion of mucosal-associated invariant T (MAIT) cells and an expansion of TRAV29/DV5-TRAJ5 + clonotypes in the blood repertoire of individuals with CD. Also, a significant depletion of multiple IGHV3-33-IGHJ4 + and IGHV3-33-IGHJ6 + clonotypes in the blood and gut IGH repertoire of individuals with CD. Discussion Our findings highlight the importance of studying the immune repertoire in a tissue-specific manner and the need to profile the T and B cell immune repertoire of gut tissues as not all disease-induced alterations will be detected in the blood.

• Andersen, Svend; Bernklev, Tomm; Størdal, Ketil; Hagen, Milada; Kristensen, Vendel Ailin & Opheim, Randi [Show all 13 contributors for this article] (2025). Specific phenotypes may drive an increased incidence of pediatric inflammatory bowel disease in South‐Eastern Norway. Journal of Pediatric Gastroenterology and Nutrition - JPGN. ISSN 0277-2116. 81(5), p. 1227–1236. doi: 10.1002/jpn3.70148. Full text in Research Archive Show summary

  Abstract Objectives Pediatric inflammatory bowel disease (PIBD) incidence has increased in recent decades but may be stabilizing, prompting exploration of incidence changes, disease distribution, and severity. Methods From 2017 to 2019, patients under 18 years with PIBD symptoms were recruited from nine hospitals in South‐Eastern Norway for Inflammatory Bowel Disease in South‐Eastern Norway III (IBSEN III), a population‐based inception cohort study. The primary outcome was a diagnosis of any PIBD subtype as defined by revised Porto criteria. Paris classification system defined disease phenotypes, and descriptions of covariates were gathered from patients in IBSEN III. Results We identified 324 PIBD patients, with 216 consenting to the IBSEN III study. The crude incidence rate was 17.8 per 100,000 person‐years (PY) (95% confidence interval [CI]: 15.9–19.8). Crohn's disease (CD) was found in 118 patients (54.6%); 48% had ileocolonic distribution, 40% had upper gastrointestinal disease, and 12.8% had perianal disease. Complications (stricturing and/or penetrating) were noted in 18%. Ulcerative colitis (UC) was diagnosed in 78 patients (36.1%), predominantly pancolitis (41%), with 30% having proctitis. One in five suffered severe disease. IBD unclassified was found in 20 patients (9.3%). PIBD incidence in those under 16 was 13.6/100,000 PY, up from 4.7 in the IBSEN study 27 years ago. Terminal ileitis (11%–23%) and proctitis (14%–25%) rose from IBSEN (1990–1993) to IBSEN III, while stricturing/penetrating disease changed insignificantly (17%–16%). Conclusions The incidence of PIBD has risen in South‐Eastern Norway, with increased cases of terminal ileitis in CD, unchanged stricturing/penetrating disease, and increased proctitis in UC compared to the original IBSEN study. Trial registration ClinicalTrials.gov identifier: NCT02727959.

• Olsen, Bjørn Christian Elias Grova; Opheim, Randi; Kristensen, Vendel Ailin; Høivik, Marte Lie; Lund, Charlotte & Aabrekk, Tone Bergene [Show all 22 contributors for this article] (2025). Prevalence of Irritable Bowel Syndrome Based on Rome IV Criteria in Patients in Biochemical and Endoscopic Remission From Newly Diagnosed Inflammatory Bowel Disease: One- and Three-Year Results (the IBSEN III Cohort). Inflammatory Bowel Diseases. ISSN 1078-0998. 31(10), p. 2704–2713. doi: 10.1093/ibd/izaf047. Full text in Research Archive Show summary

  Background: Distinguishing irritable bowel syndrome (IBS) from inflammatory bowel disease (IBD) flare-ups is challenging. This study used objective remission markers to accurately determine IBS prevalence in a population-based cohort of patients with IBD. Methods: Adults with ulcerative colitis and Crohn’s disease were recruited from the IBD in South-Eastern Norway III cohort study. Irritable bowel-like symptoms were assessed using the Rome IV criteria for patients in remission from IBD at 1- and 3-year follow-ups. Remission was defined objectively using the biochemical marker fecal calprotectin (FC) ≤ 250 μg/g, and comparisons to remission based on endoscopic indices were made at 1-year follow-up. Results: Among patients with FC ≤ 250 μg/g, IBS prevalences were 21.9% (n = 62/283) and 16.1% (n = 49/304) at the 1- and 3-year follow-ups, respectively, which were higher than that in the Norwegian population (9.5%; P < .005). Of patients in endoscopic remission at 1-year follow-up, 19.2% (n = 43/224) reported IBS-like symptoms, which was not significantly different from IBS prevalence for patients with FC ≤ 250 μg/g. Irritable bowel syndrome was independently associated with substantial fatigue (odds ratio: 3.05 [95% CI, 1.48-6.27]) and female sex (odds ratio: 2.67 [95% CI, 1.34-5.32]) at the 1-year follow-up. Patients with IBS reported significantly reduced health-related quality of life (HRQoL) scores. Conclusions: The prevalence of IBS among patients in remission from IBD was approximately twice as common as that in the Norwegian population. Irritable bowel syndrome was independently associated with substantial fatigue, female sex, and reduced HRQoL.

• Zerouga, Insaf; Valeur, Jørgen; Sommer, Christine; Carlsen, Monica Hauger; Hagen, Milada & Høivik, Marte Lie [Show all 22 contributors for this article] (2025). Habitual Intake of Macronutrients and Fermentable Oligo-, Di-, Monosaccharides and Polyols is not associated with Irritable Bowel Syndrome-like Symptoms in Inflammatory Bowel Disease. Clinical Nutrition ESPEN. ISSN 2405-4577. 67, p. 105–113. doi: 10.1016/j.clnesp.2025.03.005. Full text in Research Archive
• Strande, Vibeke; Hagen, Milada; Lund, Charlotte; Asak, Øivind Wessel; Bengtson, May-Bente & Cetinkaya, Raziye Boyar [Show all 26 contributors for this article] (2025). Predicting severe inflammatory bowel disease: a risk matrix model based on the IBSEN III inception cohort. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 60(7), p. 716–727. doi: 10.1080/00365521.2025.2512591. Full text in Research Archive Show summary

  Background and aims: Identifying patients at risk of developing severe inflammatory bowel disease (IBD) can aid treatment decisions. However, predicting disease course remains challenging. We aimed to identify predictive factors associated with severe disease course in the first year after IBD diagnosis. Methods: Newly diagnosed adult (≥18 years) patients with IBD were recruited from a population-based inception cohort (IBSEN III study). Preselected baseline factors were tested for associations with severe disease course, defined as IBD-related hospitalisation, surgery, treatment with ≥2 steroid courses, >2 biologics and/or new event of complication (stricture, fistula, abscess only applicable Crohn's disease (CD)). From a best fitted multivariable logistic regression model stratified by diagnosis and age (18-40/>40 years), probability of severe disease for given combinations of predictive factors was summarised in prediction matrices. Results: At one-year follow-up, 90/559 (16%) patients with ulcerative colitis (UC) and 74/312 (24%) with CD had severe disease. Treatment with systemic steroids, vitamin D deficiency, Simple Clinical Colitis Activity Index >2, and hypoalbuminemia at diagnosis were all significantly associated with severe disease in UC patients. CD patients with stricturing or penetrating disease behaviour, systemic steroids and hypoalbuminemia at diagnosis were associated with severe disease course. The least favourable combination of these factors increased the probability of severe disease from 3% (95%CI[0-5%]) to 72% (95%CI[66-79%]) for UC and from 8% (95%CI[3-13%]) to 88% (95%CI[84-93%]) for CD. Conclusions: Our study identified predictive factors associated with severe disease the first year after diagnosis. The probability of severe disease summarised in matrices enables easy risk stratification.

• Pertsinidou, Eleftheria; Salomon, Benita; Bergemalm, Daniel; Salihovic, Samira; Hedin, Charlotte R.H. & Lundström, Maria [Show all 30 contributors for this article] (2025). Anti-integrin αvβ6 IgG antibody as a diagnostic and prognostic marker in ulcerative colitis: A cross-sectional and longitudinal study defining a specific disease phenotype. Journal of Crohn's and Colitis. ISSN 1873-9946. 19(5). doi: 10.1093/ecco-jcc/jjaf062. Full text in Research Archive
• Hansen, Simen Hyll; Maseng, Maria Gjerstad; Grännö, Olle; Vestergaard, Marie V; Bang, Corinna & Olsen, Bjørn Christian Elias Grova [Show all 33 contributors for this article] (2025). Fecal Microbiome Reflects Disease State and Prognosis in Inflammatory Bowel Disease in an Adult Population-Based Inception Cohort. Inflammatory Bowel Diseases. ISSN 1078-0998. 31(8), p. 2066–2080. doi: 10.1093/ibd/izaf060. Full text in Research Archive
• Strande, Vibeke; Lund, Charlotte; Hagen, Milada; Bengtson, May-Bente; Cetinkaya, Raziye Boyar & Detlie, Trond Espen [Show all 23 contributors for this article] (2024). Clinical course of ulcerative colitis: Frequent use of biologics and low colectomy rate first year after diagnosis—results from the IBSEN III inception cohort. Alimentary Pharmacology and Therapeutics. ISSN 0269-2813. 60(3), p. 357–368. doi: 10.1111/apt.18097. Full text in Research Archive Show summary

  Background: The introduction of biologic therapies and the 'treat-to-target' treatment strategy may have changed the disease course of ulcerative colitis (UC). Aims: To describe the early disease course and disease outcome at 1-year follow-up in a population-based inception cohort of adult patients with newly diagnosed UC. Methods: The Inflammatory Bowel Disease in South-Eastern Norway (IBSEN) III study is a population-based inception cohort study with prospective follow-up. Patients newly diagnosed with inflammatory bowel disease during 2017-2019 were included. Patients ≥18 years at diagnosis of UC who attended the 1-year follow-up were investigated. We registered clinical, endoscopic and demographic data at diagnosis and 1-year follow-up. Results: We included 877 patients with UC (median age 36 years (range: 18-84), 45.8% female). At diagnosis, 39.2% presented with proctitis, 24.7% left-sided colitis and 36.0% extensive colitis. At the 1-year follow-up, 13.9% experienced disease progression, and 14.5% ha

• Lund, Charlotte; Strande, Vibeke; Hagen, Milada; Bengtson, May-Bente; Cetinkaya, Raziye Boyar & Detlie, Trond Espen [Show all 26 contributors for this article] (2024). Low Surgery Rates in Early Crohn's Disease: Results from a Prospective Population-Based Inception Cohort—The Inflammatory Bowel Disease in South-Eastern Norway III Study. Inflammatory Bowel Diseases. ISSN 1078-0998. doi: 10.1093/ibd/izae297. Full text in Research Archive Show summary

  Background and aims: The emergence of biologic therapy has coincided with a decline in surgery rates for Crohn's disease (CD). This study aims to describe the disease course, including intra-abdominal surgery rates, biologic therapy use, and variables associated with biologic therapy initiation in a cohort of newly diagnosed CD patients. Methods: The Inflammatory Bowel Disease in South-Eastern Norway (IBSEN) III study is a population-based inception cohort study. From 2017 to 2019, newly diagnosed inflammatory bowel disease patients were included for prospective follow-up. The present study included CD patients ≥ 18 years. Clinical, endoscopic, and demographic data were collected at diagnosis and 1-year follow-up. Data were analyzed by using the Kaplan-Meier method and regression analyses. Results: In total, 424 CD patients (median age 37.0 years (range 18-80), female 55.0%) were included. At diagnosis, 50.5% presented with ileal disease and 80.7% with inflammatory behavior. Within a 1-year follow-up, 39.6%

• Dale, Hanna Fjeldheim; Hagen, Milada; Malmstrøm, Gunn Helen; Fiennes, Jennifer Twisleton; Høivik, Marte Lie & Kristensen, Vendel Ailin [Show all 7 contributors for this article] (2024). Assessing hard and loose “endpoints”: comparison of patient and expert Bristol Stool Scale scoring of 2280 fecal samples. F1000 Research. 13. doi: 10.12688/f1000research.152496.2. Full text in Research Archive Show summary

  Background Stool consistency is an important outcome measure to evaluate in the investigation of several gastrointestinal diseases. The Bristol Stool Scale (BSS) is one of the most commonly used tools for evaluation of stool consistency. BSS ranges from 1-7 and each score is assigned to a given consistency of the feces. Self-reported characterizations can differ from an expert evaluation, and the reliability of BSS is unclear. We aimed to evaluate the reliability of BSS by comparing patient scores with expert scores. Methods Patients with inflammatory bowel disease collected stool samples throughout a 3-year follow-up. The stool´s consistency was evaluated with BSS by the patients and matched with an expert score. Agreement between patient and expert scores was assessed using Cohen’s kappa. Results BSS scores from 2280 fecal samples collected from 992 patients at up to five time points were included. When all samples were compared, there was good to substantial agreement between patient and expert scores (Cohen’s weighted kappa: 0.66-0.72). When the BSS scores were simplified and categorized as 1 (scores 1-2), 2 (scores 3-5) or 3 (scores 6-7), the agreement improved slightly (Cohen’s weighted kappa: 0.73-0.77). When the scores from the first sample per patient were compared, the experts were more likely to assign higher scores compared to the patient. The proportion of the lowest assigned scores (1-2) was 12.1% for patients and 8.1% for experts. Conclusions The agreement between patient and expert BSS scores is good to substantial, especially when the BSS scores are simplified into three categories.

• Holten, Kristina Ingeborg; Bernklev, Tomm; Opheim, Randi; Olsen, Bjørn Christian Elias Grova; Detlie, Trond Espen & Strande, Vibeke [Show all 18 contributors for this article] (2024). Fatigue in Patients with Inflammatory Bowel Disease in Remission One Year after Diagnosis (the IBSEN III Study). Journal of Crohn's and Colitis. ISSN 1873-9946. 19(4). doi: 10.1093/ecco-jcc/jjae170. Full text in Research Archive Show summary

  Background and aims: Fatigue is commonly observed in Crohn's disease (CD) and ulcerative colitis (UC), but its association to achieving remission is not clearly established. In this study we describe the odds for fatigue in patients with CD/UC one year after diagnosis based on different definitions of remission and identified factors associated with chronic fatigue (CF) among patients in endoscopic/radiological remission. Methods: Patients ≥18 years with CD/UC were recruited from the IBSEN III cohort. Using the Fatigue Questionnaire, and dichotomizing the score, CF was defined as the presence of substantial fatigue (SF) for ≥6 months. Remission was divided into symptomatic (CD: HBI score<5/UC: SCCAI score<3), biochemical (faecal calprotectin ≤250µg/g), endoscopic/radiological (CD: normal intestinal MRI/CT combined with normal endoscopy/UC: Mayo endoscopic score 0) and histological (normal mucosal biopsies). Both the likelihood of SF/CF, depending on the definition of remission, and associations between CF an

• Zerouga, Insaf; Valeur, Jørgen; Sommer, Christine; Småstuen, Milada Cvancarova; Medhus, Asle Wilhelm & Lund, Charlotte [Show all 22 contributors for this article] (2024). Dietary intake and nutritional status in patients with newly diagnosed inflammatory bowel disease: insights from the IBSEN III study. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 59(6), p. 1–9. doi: 10.1080/00365521.2024.2313056. Full text in Research Archive Show summary

  Background: Dietary recommendations in inflammatory bowel disease (IBD) are inconclusive, and patients may follow restrictive diets with increased risk of malnutrition. The aim of this study was to compare dietary intakes and nutritional status in men and women with newly diagnosed IBD with a general population sample, and to investigate whether intakes were in line with the Nordic Nutrition Recommendations. Methods: This was a cross-sectional study including adults≥ 40 years with IBD from the Inflammatory Bowel Disease in South-Eastern Norway (IBSEN) III cohort study. A validated food frequency questionnaire (FFQ) was used in dietary data collection, and a sample from the seventh survey of the Tromsø Study was included as a comparison group. Results: A total of 227 men and women with IBD were included. IBD patients had higher intake of grain products, sweetened beverages, energy, fat and polyunsaturated fat (PUFA), but lower intake of dairy products, alcohol and iodine compared to adults from the comparison sample (p < 0.01). Intakes of saturated fat and carbohydrates in both genders, and vitamin D in women were not within recommended levels. Anemia and hypoalbuminemia were more prevalent in IBD patients than in the comparison sample. Conclusions: Dietary intakes in newly diagnosed IBD patients were mostly in line with Nordic Nutrition Recommendations. Higher proportion of IBD patients exceeded recommended allowances of fat and added sugar than the comparison sample. Insufficient micronutrient intake, anemia and hypoalbuminemia are present challenges in IBD patients that require monitoring.

• Johansen, Ingunn; Småstuen, Milada Cvancarova; Løkkeberg, Stine Eileen Torp; Kristensen, Vendel Ailin; Høivik, Marte Lie & Lund, Charlotte [Show all 16 contributors for this article] (2023). Symptoms and symptom clusters in patients newly diagnosed with inflammatory bowel disease: results from the IBSEN III Study. BMC Gastroenterology. 23(1). doi: 10.1186/s12876-023-02889-y. Full text in Research Archive Show summary

  Patients with inflammatory bowel disease report multiple symptoms, but the relationships among co-occurring symptoms are poorly understood. This study aimed to examine the prevalence of symptoms and explore symptom clusters and possible associations between symptom clusters and socio-demographic and clinical variables in patients newly diagnosed with inflammatory bowel disease. Methods The IBSEN III study is a prospective population-based inception cohort of patients with inflammatory bowel disease. This study used patient data from the three largest hospitals in the study catchment area. The Memorial Symptom Assessment Scale was used to assess the prevalence of symptoms. Symptom clusters were identified using principal component analysis. Possible associations between socio-demographic and clinical variables and symptom cluster membership were estimated using regression analysis. Results Of the 573 patients (age, ≥18 years) diagnosed with inflammatory bowel disease, 350 (61.1%) completed the questionnaire (responders). Eleven symptoms were reported by >50% of the responders. The three most prevalent symptoms were bloating (84%), drowsiness (81%), and lack of energy (81%). Three symptom clusters were identified: psychological (56% of the patients), impaired energy (28%), and physical (16%) clusters. Multinomial regression analysis revealed that vitamin D deficiency was significantly associated with the impaired energy cluster (odds ratio=2.49, 95% confidence interval [1.00-6.2], p=0.05). Conclusions We found high symptom prevalence in patients newly diagnosed with inflammatory bowel disease. Three distinct symptom clusters were identified, and the psychological cluster includes >50% of the patients. Vitamin D deficiency is the only factor associated with cluster membership, namely the impaired energy cluster.

• García-Morales, Natalia; Pérez-Aísa, Ángeles; Fiorini, Giulia; Tepes, Bojan; Castro-Fernández, Manuel & Lucendo, Alfredo [Show all 52 contributors for this article] (2023). Helicobacter pylori Diagnostic Tests Used in Europe: Results of over 34,000 Patients from the European Registry on Helicobacter pylori Management. Journal of Clinical Medicine. 12(13), p. 1–14. doi: 10.3390/jcm12134363. Full text in Research Archive
• Holten, Kristina Ingeborg; Bernklev, Tomm; Opheim, Randi; Johansen, Ingunn; Olsen, Bjørn Christian Elias Grova & Lund, Charlotte [Show all 22 contributors for this article] (2023). Fatigue in Patients with Newly Diagnosed Inflammatory Bowel Disease: Results from a Prospective Inception Cohort, the IBSEN III Study. Journal of Crohn's and Colitis. ISSN 1873-9946. 17(11), p. 1781–1790. doi: 10.1093/ecco-jcc/jjad094. Full text in Research Archive Show summary

  Background and aims: Although fatigue is common in inflammatory bowel disease (IBD), its pathogenesis remains unclear. This study aimed to determine the prevalence of fatigue and its associated factors in a cohort of patients newly diagnosed with IBD. Methods: Patients ≥18 years were recruited from the Inflammatory Bowel Disease South-Eastern Norway (IBSEN III) study, a population-based, observational inception cohort. Fatigue was assessed using the Fatigue Questionnaire and compared with data from a Norwegian general population. Univariate and multivariate linear and logistic regression analyses were performed to evaluate the associations of total fatigue (TF) (continuous score) and substantial fatigue (SF) (dichotomized score ≥4) with sociodemographic, clinical, endoscopic, laboratory, and other relevant patient data. Results: In total, 983/1509 (65.1%) patients with complete fatigue data were included (ulcerative colitis (UC), 68.2%; Crohn's disease (CD), 31.8%). The prevalence of SF was higher in CD (69.6%) compared with UC (60.2%) (p<0.01), and in both diagnoses when compared to the general population (p<0.001).In the multivariate analyses, depressive symptoms, pain intensity, and sleep disturbances were associated with increased TF for both diagnoses. In addition, increased clinical disease activity and Mayo endoscopic score were significantly associated with TF in UC, whereas all disease-related variables were insignificant in CD. Similar findings were observed for SF, except regarding the Mayo endoscopic score. Conclusions: SF affects approximately two-thirds of patients newly diagnosed with IBD. Fatigue was associated with depressive symptoms, sleep disturbances, and increased pain intensity in both diagnoses, while clinical and endoscopic activity were associated factors only in UC.

• Olsen, Bjørn Christian Elias Grova; Opheim, Randi; Høivik, Marte Lie; Lund, Charlotte; Aabrekk, Tone Bergene & Johansen, Ingunn [Show all 15 contributors for this article] (2023). Health-related quality of life in patients with newly diagnosed inflammatory bowel disease: an observational prospective cohort study (IBSEN III). Quality of Life Research. ISSN 0962-9343. 32(10), p. 2951–2964. doi: 10.1007/s11136-023-03435-9. Full text in Research Archive Show summary

  Purpose This unselected, population-based cohort study aimed to determine the level of health-related quality of life (HRQoL) in patients with Crohn’s disease (CD) and ulcerative colitis (UC) at the time of diagnosis compared with a reference population and identify the demographic factors, psychosocial measures, and disease activity markers associated with HRQoL. Methods Adult patients newly diagnosed with CD or UC were prospectively enrolled. HRQoL was measured using the Short Form 36 (SF-36) and Norwegian Inflammatory Bowel Disease Questionnaires. Clinical significance was assessed using Cohen’s d effect size and further compared with a Norwegian reference population. Associations between HRQoL and symptom scores, demographic factors, psychosocial measures, and disease activity markers were analyzed. Results Compared with the Norwegian reference population, patients with CD and UC reported significantly lower scores in all SF-36 dimensions, except for physical functioning. Cohen’s d effect sizes for men and women in all SF-36 dimensions were at least moderate, except for bodily pain and emotional role for men with UC and physical functioning for both sexes and diagnoses. In the multivariate regression analysis, depression subscale scores ≥ 8 on the Hospital Anxiety and Depression Scale, substantial fatigue, and high symptom scores were associated with reduced HRQoL. Conclusion Patients newly diagnosed with CD and UC reported statistically and clinically significantly lower scores in seven of the eight SF-36 dimensions than the reference population. Symptoms of depression, fatigue, and elevated symptom scores were associated with poorer HRQoL.

• Evensen, Helge; Sandstad, Olav; Larssen, Lene; Hagen, Milada; Kristensen, Vendel Ailin & Søvik, Torgeir Thorson [Show all 9 contributors for this article] (2023). Intraoperative distensibility measurement in POEM for achalasia: impact on patient outcome and associations with other outcome variables at 1-year follow-up. Surgical Endoscopy. ISSN 0930-2794. 37, p. 9283–9290. doi: 10.1007/s00464-023-10494-z. Full text in Research Archive Show summary

  Background and aims The functional luminal imaging probe (FLIP) can provide measurements of lower esophageal sphincter (LES) distensibility. Studies report that use of intraoperative FLIP examination during peroral endoscopic myotomy (POEM) for achalasia is associated with treatment success, but evidence is limited and inconsistent. The main aim of the present study was to assess associations between intraoperative FLIP values and 1-year outcomes. Additionally, associations between 1-year FLIP measurements and other 1-year outcome variables were studied. Methods We performed a single-center prospective study of consecutive achalasia patients treated with POEM with a standardized 1-year follow-up. The inclusion period was from June 2017 to January 2020. We compared 1-year outcomes (FLIP measurement values, Eckardt score (ES), reflux esophagitis, timed barium esophagogram (TBE), and lower esopha- geal sphincter resting pressure (LES-rp)) in patients with and without intraoperative FLIP examination. We also assessed associations between intraoperative FLIP values, 1-year FLIP values, and other 1-year outcomes. Results are given as median (IQR), and non-parametrical statistical analyses were applied. Results Sixty-two patients (27 females) with median age 45 years (35–54) were included. Baseline characteristics were similar in patients with (n = 32) and without (n = 30) intraoperative FLIP examination. In patients with intraoperative FLIP, ES was 2 (1–3) and LES distensibility index (DI) 3.7 (2.6–5.4) after 1 year, compared with ES 2 (1–3) and DI 4.0 (3.1–6.8)) in patients without intraoperative FLIP (ns). Intraoperative DI was not correlated with 1-year ES or DI. One-year DI cor- related significantly with 1-year ES (rs − 0.42), TBE (rs − 0.34), and LES-rp (rs − 0.29). Conclusions Use of intraoperative FLIP measurements in POEM for achalasia is not associated with improved 1-year out- come, and the clinical value of intraoperative FLIP in POEM for achalasia is questioned. Follow-up FLIP measurements are moderately associated with symptomatic outcome, and may serve as an additional diagnostic modality in post-treatment evaluation.

• Evensen, Helge; Hjermstad, Marianne Jensen; Småstuen, Milada Cvancarova; Kristensen, Vendel Ailin; Larssen, Lene & Skattum, Jorunn Pettersen [Show all 9 contributors for this article] (2022). Quality of life in patients with achalasia: Associations with Eckardt score and objective treatment outcomes after peroral endoscopic myotomy. Endoscopy International Open. 10(12). doi: 10.1055/a-1968-7682. Full text in Research Archive Show summary

  Background and study aims Knowledge on self-reported quality of life (QoL) in achalasia and QoL improvements after peroral endoscopic myotomy (POEM) is limited. Furthermore, the clinical role of QoL in achalasia follow-up has not been evaluated. The present study aimed to examine QoL in achalasia patients before and after POEM and assess associations between QoL, Eckardt score (ES) and objective results. Patients and methods This was a single-center prospective study of treatment-naïve achalasia patients with 12-month follow-up after POEM including manometry, upper endoscopy, 24-hour pH registration, and timed barium esophagogram. QoL data were registered using European Organisation for Research and Treatment of Cancer core questionnaire (QLQ-C30) and esophageal module (QLQ-OES18). Comparison with a reference population was performed to assess impact of achalasia on QoL and effect of therapy. Mixed models for repeated measures were applied. Results Fifty patients (26 females) with a median age of 47 years (18-76) were included. Before treatment, all QoL domains were significantly impaired compared with an age- and gender-adjusted reference population ( P < 0.05). No significant QoL-differences were found after POEM, except for fatigue and nausea/vomiting. Clinically relevant QoL improvement was observed in ≥ 50 % of the patients in all QoL domains, except for physical and role functioning. QoL was significantly associated with ES ( P < 0.05) but not with objective results. Conclusions Achalasia is associated with severe QoL impairment. Following POEM, a significant and clinically relevant QoL improvement is observed. QoL is associated with ES, but not with objective results after POEM. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).

• Evensen, Helge; Småstuen, Milada Cvancarova; Schulz, Anselm; Kristensen, Vendel Ailin; Larssen, Lene & Skattum, Jorunn Pettersen [Show all 9 contributors for this article] (2021). One year comprehensive prospective follow-up of achalasia patients after peroral endoscopic myotomy. Annals of Medicine. ISSN 0785-3890. 53(1), p. 2227–2235. doi: 10.1080/07853890.2021.2005253. Full text in Research Archive Show summary

  Peroral endoscopic myotomy (POEM) is an established therapy for achalasia, but outcome evaluation has often been limited to Eckardt score (ES). The present study was aimed to improve knowledge about outcome evaluation and predictive outcome factors by performing a comprehensive objective evaluation of achalasia patients treated by POEM. Methods: This single centre prospective study reports outcome data 12 months after POEM in treatment-naive achalasia patients. A predefined follow-up protocol included ES, high resolution manometry, 24-h pH measurement, upper endoscopy and timed barium esophagogram (TBE). Univariate and multivariate regression analyses were performed to analyze association between post-POEM variables and identify predictive factors for objective outcome. Results: Fifty patients were included with a drop-out rate of < .001), and 28% (13/47) of the patients had a positive 24-h pH registration. An oesophageal diameter >3 cm after POEM was associated with treatment failure assessed by ES (p ¼ .04) and TBE (p ¼ .03). Advanced achalasia stage (p ¼ .02) and long symptom duration (p ¼ .04) were identified as independent predictive factors for poor outcome assessed by TBE. Conclusions: The present study confirms that POEM is an efficient therapy for achalasia. The comprehensive objective evaluation after POEM demonstrates that long symptom duration and major changes in oesophageal anatomy at diagnosis imply poor treatment outcome, and a post-POEM dilated oesophagus is associated with treatment failure.

• Kristensen, Vendel Ailin; Opheim, Randi; Perminow, Gøri Margrete; Huppertz-Hauss, Gert; Detlie, Trond Espen & Lund, Charlotte [Show all 39 contributors for this article] (2021). Inflammatory bowel disease in South-Eastern Norway III (IBSEN III): a new population-based inception cohort study from South-Eastern Norway. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 56(8), p. 899–905. doi: 10.1080/00365521.2021.1922746. Full text in Research Archive Show summary

  Background and aim: Modern treatment strategies for inflammatory bowel disease (IBD) are postulated to change the natural disease course. Inception cohort studies are the gold standard for investigating such changes. We have initiated a new population-based inception cohort study; Inflammatory bowel disease in South Eastern Norway III (IBSEN III). In this article, we describe the study protocol and baseline characteristics of the cohort. Methods: IBSEN III is an ongoing, population-based observational inception cohort study with prospective follow-up. Adult and pediatric patients with suspected IBD in the South-Eastern Health Region of Norway (catchment area of 2.95 million inhabitants in 2017), during the 3-year period from 2017 to 2019, were eligible for inclusion. Comprehensive clinical, biochemical, endoscopic, demographic, and patient-reported data were collected at the time of diagnosis and throughout standardized follow-up. For a portion of the patients, extensive biological material was biobanked. Results: The study included 2168 patients, of whom 1779 were diagnosed with IBD (Crohn's disease: 626, ulcerative colitis: 1082, IBD unclassified: 71). In 124 patients, there were subtle findings indicative of, but not diagnostic for, IBD. The remaining 265 patients were classified as symptomatic non-IBD controls. Conclusion: We have included patients in a comprehensive population-based IBD cohort from a catchment population of 2.95 million, and a unique biobank with materials from newly diagnosed and treatment-naïve IBD patients and symptomatic non-IBD controls. We believe this cohort will add important knowledge about IBD in the years to come.

• Kristensen, Vendel Ailin; Volkmann, Hilde Løland Von; Østvik, Ann Elisabet & Jahnsen, Jørgen (2021). Medisinsk behandling av Crohns sykdom. NGF-nytt. ISSN 0809-6570. 28(4), p. 8–13. Full text in Research Archive
• Kristensen, Vendel Ailin; Småstuen, Milada Cvancarova; Høivik, Marte Lie; Moum, Bjørn & Vatn, Morten H (2020). Serological antibodies and surgery in a population-based inception cohort of Crohn's disease patients - the IBSEN study. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. doi: 10.1080/00365521.2020.1745879. Full text in Research Archive Show summary

  Introduction: Serological antibodies have been associated with complicated disease course in Crohn’s disease (CD), including the need for surgery. Aim: The aim of this study was to investigate if a panel of relevant antibodies could predict surgery in a prospective population-based cohort of patients with CD. Methods: The population-based IBSEN cohort has been followed prospectively for 20years. At the 10and 20-year follow-up, the following panel of serological antibodies was analysed: pANCA, ASCA IgA, ASCA IgG, anti-OmpC, anti-I2, and anti-CBir1. At the 20-year follow-up or until lost to follow-up, all CDrelated surgeries were registered. Results: Serum was available from 159 patients at 10-year follow-up and 135 patients at 20-year follow-up. In 113 patients, serum was available at both time points. No significant change of antibody status (positive vs. negative) was found from 10-year to 20-year follow-up. Negative pANCA, positive ASCA IgA and positive ASCA IgG at 10-year follow-up were all individually associated with increased risk for CD-related surgery. There was no association between anti-OmpC, anti-I2 or anti-CBir1 and CDrelated surgery. In a multiple regression model including disease location and behaviour, only stricturing or penetrating disease behaviour and negative pANCA remained significantly associated with higher odds for surgery. Conclusion: Positive ASCA IgA and IgG, and negative pANCA were associated with higher odds for CD-related surgery in univariate analysis. Since disease phenotype changes during the disease course, while serological antibodies are stable, our results support the use of pANCA, ASCA IgA and ASCA IgG as prognostic markers in CD.

• Kristensen, Vendel Ailin; Valeur, Jørgen; Brackmann, Stephan; Jahnsen, Jørgen; Brunborg, Cathrine & Tveito, Kari (2019). Attention deficit and hyperactivity disorder symptoms respond to gluten-free diet in patients with coeliac disease. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 54(5), p. 571–576. doi: 10.1080/00365521.2019.1608467. Full text in Research Archive
• Evensen, Helge; Kristensen, Vendel Ailin; Larssen, Lene; Sandstad, Olav; Hauge, Truls & Medhus, Asle Wilhelm (2019). Outcome of peroral endoscopic myotomy (POEM) in treatment-naive patients. A systematic review. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 54(1), p. 1–7. doi: 10.1080/00365521.2018.1549271. Full text in Research Archive Show summary

  Objectives: Achalasia is a primary motility disorder of the esophagus characterized by aperistalsis and failure of lower esophageal sphincter (LES) relaxation. Treatment of achalasia aims at reducing LES pressure. The common treatment modalities are laparoscopic Heller myotomy and pneumatic dilatation, but during the last decade, a promising treatment, per oral endoscopic myotomy (POEM), has been introduced. The aim of the present study was to perform a systematic review of the literature to assess the outcome of POEM in treatment-naive patients. Materials and methods: A systematic literature search in PubMed, Embase and Cochrane databases was performed using the terms ‘Achalasia AND (POEM OR peroral endoscopic myotomy OR per-oral endoscopic myotomy)’. Inclusion criteria were: original article; English language; n ≥ 20 with ≥90% treatment-naive patients; follow-up ≥3 months; and outcome evaluation of POEM including symptom score and objective tests. Exclusion criteria were: reviews and meta-analyses; pediatric data; duplicates; and articles with overlapping data material. Results: Of the 1641 articles identified, seven were included. The included studies all reported a short-term clinical success of >90%. Clinical success including post-POEM reflux was mainly estimated by symptom scorings. There were few procedure-related complications. Conclusions: The studies of treatment-naive patients indicate a high rate of clinical success. Nevertheless, a more systematic and standardized evaluation is recommended to improve the reports on outcome of POEM. The follow-up rate should be high and the evaluation protocol should include both symptom scoring and objective testing with predefined treatment goals.

• Kristensen, Vendel Ailin; Røseth, Arne; Ahmad, Tahir Riaz; Skar, Viggo Øystein & Moum, Bjørn (2017). Fecal Calprotectin: A Reliable Predictor of Mucosal Healing after Treatment for Active Ulcerative Colitis. Gastroenterology Research and Practice. ISSN 1687-6121. 2017. doi: 10.1155/2017/2098293. Full text in Research Archive Show summary

  Objectives. Mucosal healing has become the new goal of treatment in ulcerative colitis. Fecal calprotectin has been demonstrated to differentiate between mucosal inflammation and mucosal healing. With this project, we investigated whether a reduction in f-calprotectin to <250 μg/g after medical treatment for active ulcerative colitis could predict mucosal healing. Material and Methods. After a baseline colonoscopy, 20 patients with active ulcerative colitis were followed with consecutive fecal calprotectin monthly until two measurements of fecal calprotectin < 250 μg/g or a maximum follow-up of 12 months. A flexible sigmoidoscopy was then performed and Mayo endoscopic subscore was used to evaluate degree of inflammation. Simple Clinical Colitis Activity Index was used for evaluation of clinical disease activity. Results. A total of 16 patients achieved fecal calprotectin < 250 μg/g during follow-up, and all 16 patients had endoscopic mucosal healing (Mayo endoscopic subscore of ≤1) on the second endoscopy. The remaining four patients had persistently high f-calprotectin levels before the second endoscopy with Mayo endoscopic subscore corresponding to endoscopic mucosal healing in three out of four patients. Conclusions. Fecal calprotectin <250 μg/g after medical treatment for active ulcerative colitis is a reliable marker of endoscopic mucosal healing.

• Kristensen, Vendel Ailin; Lauritzen, Trine; Jelsness-Jørgensen, Lars-Petter; Frigstad, Svein Oskar; Corwin, Christian & Moum, Bjørn (2016). Patient-performed extraction of faecal calprotectin. Clinical Chemistry and Laboratory Medicine. ISSN 1434-6621. 54(8), p. 1357–1363. doi: 10.1515/cclm-2015-1037. Full text in Research Archive
• Kristensen, Vendel Ailin; Malmstrøm, Gunn Helen; Skar, Viggo Øystein; Røseth, Arne & Moum, Bjørn (2016). Clinical importance of faecal calprotectin variability in inflammatory bowel disease: Intra-individual variability and standardisation of sampling procedure. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 51(5), p. 548–555. doi: 10.3109/00365521.2015.1117650. Full text in Research Archive
• Kristensen, Vendel Ailin; Lauritzen, Trine; Jelsness-Jørgensen, Lars-Petter & Moum, Bjørn (2015). Validation of a new extraction device for measuring faecal calprotectin in inflammatory bowel disease, and comparison to established extraction methods. Scandinavian Journal of Clinical and Laboratory Investigation. ISSN 0036-5513. 75(5), p. 355–361. doi: 10.3109/00365513.2015.1030765. Full text in Research Archive Show summary

  Objective: Faecal (f-) calprotectin is a widely used surrogate marker of intestinal inflammation. F-calprotectin analysis is labour demanding partly due to a time consuming extraction step. The aim of this project was to validate a new extraction method for f-calprotectin. Material and methods: A prospective multicentre study included 135 patients with an established diagnosis of inflammatory bowel disease. The patients submitted a faeces sample, which was extracted with both the conventional method at the participating laboratory and the new extraction device. The extracts were analyzed by an automated ELISA instrument. Results: Method comparison of the traditional method and the new device showed a slope of 1.01 (0.93–1.07) with intercept of − 2.2 (− 4.9–0.6). The Spearman rank correlation coefficient was 0.96. Conclusions: The new extraction device is a reliable and time saving alternative to the conventional extraction method.

• Kristensen, Vendel Ailin; Klepp, Pasquale Catherine; Småstuen, Milada Cvancarova; Røseth, Arne; Skar, Viggo Øystein & Moum, Bjørn (2015). Prediction of endoscopic disease activity in ulcerative colitis by two different assays for faecal calprotectin. Journal of Crohn's and Colitis. ISSN 1873-9946. 9(2), p. 164–169. doi: 10.1093/ecco-jcc/jju015. Full text in Research Archive

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• Maseng, Maria Gjerstad; Hansen, S Hyll; Bang, Corina; Valeur, Jørgen; Huppertz-Hauss, Gert & Opheim, Randi [Show all 18 contributors for this article] (2025). Longitudinal Changes in Gut Microbiota During the First Year following diagnosis of Inflammatory Bowel Disease – the IBSEN III study. Journal of Crohn's and Colitis. ISSN 1873-9946. 19, p. i2387–i2387. doi: 10.1093/ecco-jcc/jjae190.1498. Full text in Research Archive
• Maseng, Maria Gjerstad; Hansen, Simen Hyll; Bang, Corina; Valeur, Jørgen; Huppertz-Hauss, Gert & Opheim, Randi [Show all 18 contributors for this article] (2025). Longitudinal Changes in Gut Microbiota During the First Year following diagnosis of Inflammatory Bowel Disease – the IBSEN III study. Full text in Research Archive
• Strande, Vibeke; Høivik, Marte Lie & Kristensen, Vendel Ailin (2024). Letter: Critical appraisal of biologic therapy in early ulcerative colitis management—Addressing study limitations and the role of psychological resilience—Authors' reply. Alimentary Pharmacology and Therapeutics. ISSN 0269-2813. doi: 10.1111/apt.18187. Full text in Research Archive
• Valeur, Jørgen; Tveito, Kari; Røseth, Arne; Strøm, Finn; Kristensen, Vendel Ailin & Sandstad, Olav [Show all 9 contributors for this article] (2024). Minneord: Viggo Øystein Skar (1945-2024). Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 144(14), p. 1155–1155. Full text in Research Archive
• Maseng, Maria Gjerstad; Hansen, Simen Hyll; Bang, Corina; Detlie, Trond Espen; Huppertz-Hauss, Gert & Kristensen, Vendel Ailin [Show all 18 contributors for this article] (2024). Longitudinal Changes in Gut Microbiota During the First Year following diagnosis of Inflammatory Bowel Disease– the IBSEN III study. Full text in Research Archive
• Bazov, I.; Kruse, R.; Bergemalm, D.; Eriksson, C.; Hedin, C.R. & Nieuwenhoven, M. van [Show all 28 contributors for this article] (2023). A novel serum protein signature as biomarker for Inflammatory Bowel Disease: A diagnostic performance and prediction modelling study using data from two independent inception cohorts. Journal of Crohn's and Colitis. ISSN 1873-9946. 17, p. i314–i315. doi: 10.1093/ecco-jcc/jjac190.0284. Full text in Research Archive
• Mathisen, Carl Magnus Bache Wiig; Nyström, N.; Bazov, I.; Andersen, S.; Olbjørn, Christine & Perminow, Gøri Margrete [Show all 22 contributors for this article] (2023). A novel diagnostic serum protein signature for paediatric Inflammatory Bowel Disease: A discovery and validation study in two independent inception cohorts. Journal of Crohn's and Colitis. ISSN 1873-9946. 17, p. i71–i71. doi: 10.1093/ecco-jcc/jjac190.0051. Full text in Research Archive
• Hansen, Simen Hyll; Maseng, M Gjerstad; Bjørkqvist, O; Halfvarsson, J; Bang, C & Detlie, Trond Espen [Show all 23 contributors for this article] (2023). Gut microbiota at diagnosis is associated with clinical features and future disease course in Inflammatory Bowel Disease: Data from IBSEN III, a new large Norwegian population-based inception cohort. Journal of Crohn's and Colitis. ISSN 1873-9946. 17, p. i1028–I2029. doi: 10.1093/ecco-jcc/jjac190.1050. Full text in Research Archive
• Zerouga, Insaf; Sommer, Christine; Carlsen, Monica Hauger; Valeur, Jørgen; Kristensen, Vendel Ailin & Høivik, Marte Lie [Show all 8 contributors for this article] (2023). Kosthold og ernæringsstatus ved nydiagostisert IBD: resultater fra IBSEN III. Full text in Research Archive
• Johansen, Ingunn; Småstuen, Milada Cvancarova; Løkkeberg, Stine Eileen Torp; Kristensen, Vendel Ailin; Høivik, Marte Lie & Lund, Charlotte [Show all 16 contributors for this article] (2022). Symptoms and symptom clusters in patients newly diagnosed with inflammtory bowel disease – results from the IBSEN III study. Full text in Research Archive
• Strande, Vibeke; Småstuen, Milada C.; Lund, Charlotte; Bengtson, May-Bente; Høie, Ole & Cetinkaya, Raziye Boyar [Show all 26 contributors for this article] (2022). Klinisk karakteristika hos nydiagnostiserte pasienter med inflammatorisk tarmsykdom - resultater fra IBSEN III-studien. Full text in Research Archive
• Strande, Vibeke; Småstuen, Milada C; Huppertz-Hauss, Gert; Perminow, Gøri; Henriksen, Magne & Bengtson, May-Bente [Show all 17 contributors for this article] (2022). Fecal calprotectin at diagnosis is associated with oral steroid use first year of inflammatory bowel disease. Full text in Research Archive
• Kristensen, Vendel Ailin (2021). Inflammatorisk tarmsykdom - hva bør du vite? Norsk Farmaceutisk Tidsskrift (NFT). ISSN 0029-1935. Full text in Research Archive
• Strande, Vibeke; Småstuen, Milada C.; Hasund, Audun; Huppertz-Hauss, Gert; Pallenschat, Jens & Bengtson, May-Bente [Show all 18 contributors for this article] (2021). Clinical characteristics associated with biochemical remission three months after diagnosis of ulcerative colitis. Full text in Research Archive
• Strande, Vibeke; Småstuen, Milada C.; Hasund, Audun; Huppertz-Hauss, Gert; Pallenschat, Jens & Bengtson, May-Bente [Show all 18 contributors for this article] (2021). Clinical characteristics associated with biochemical remission three months after diagnosis of Crohn's disease. Full text in Research Archive
• Mortensen, Joachim Høg; Lunder, Aida Kapic; Manon-Jensen, Tina; Karsdal, MA; Nielsen, Mette & Leeming, DJ [Show all 13 contributors for this article] (2020). P117 Biomarkers of extracellular matrix remodelling are associated with intestinal fibrosis assessed by magnetic resonance enterography and accumulated intestinal damage (Lémann index): the IBSEN study. Full text in Research Archive
• Kristensen, Vendel Ailin; Lund, Charlotte; Opheim, Randi; Ricanek, Petr; Huppertz-Hauss, Gert & Perminow, Gøri Margrete [Show all 37 contributors for this article] (2020). Inflammatory Bowel Disease in South-Eastern Norway III – IBSEN III. Full text in Research Archive
• Kristensen, Vendel Ailin (2020). Bred studie av IBD fortsetter. Fordøyelsen. Tidsskrift for landsforeningen mot fordøyelsessykdommer. Full text in Research Archive
• Kristensen, Vendel Ailin; Valeur, Jørgen; Brackmann, Stephan; Jahnsen, Jørgen & Tveito, Kari (2019). Kognitive symptomer hos pasienter med cøliaki før og etter glutenfri kost. Full text in Research Archive
• Kristensen, Vendel Ailin; Opheim, Randi; Ricanek, Petr; Detlie, Trond Espen; Perminow, Gøri Margrete & Høivik, Marte Lie (2018). IBSEN III—a new population-based inception cohort from South-Eastern Norway. Full text in Research Archive
• Kristensen, Vendel Ailin; Valeur, Jørgen & Tveito, Kari (2018). Cognitive impairment in coeliac disease: normalization following gluten-free diet. United European Gastroenterology Journal (UEG Journal). ISSN 2050-6406. 6, p. A330–A330. Full text in Research Archive
• Kristensen, Vendel Ailin; Valeur, Jørgen & Tveito, Kari (2018). Cognitive impairment in coeliac disease: normalization following gluten-free diet. Full text in Research Archive
• Lauritzen, Trine & Kristensen, Vendel Ailin (2018). Måling av kalprotektin i feces. Klinisk Biokemi i Norden. ISSN 1101-2013. 30(1), p. 38–41. Full text in Research Archive
• Kristensen, Vendel Ailin (2018). Inflammatory Bowel Disease of South-Eastern Norway – IBSEN III-studien - Første års inklusjon viser økende insidens av IBD. NGF-nytt. ISSN 0809-6570. p. 30–31. Full text in Research Archive
• Kristensen, Vendel Ailin (2018). Familieplanlegging, svangerskap og amming ved inflammatorisk tarmsykdom. NGF-nytt. ISSN 0809-6570. p. 10–12. Full text in Research Archive
• Kristensen, Vendel Ailin; Småstuen, Milada Cvancarova; Høivik, Marte Lie; Moum, Bjørn & Vatn, Morten (2018). Long term stability of serological antibodies in a population-based inception cohort of inflammatory bowel disease - The IBSEN study. Full text in Research Archive
• Kristensen, Vendel Ailin; Røseth, Arne; Ahmad, Tahir; Skar, Viggo Øystein & Moum, Bjørn (2016). Faecal calprotectin is a useful marker of mucosal healing after treatment for active ulcerative colitis. Full text in Research Archive
• Kristensen, Vendel Ailin; Malmstrøm, Gunn; Skar, Viggo Øystein & Moum, Bjørn (2015). Clinical relevance of faecal calprotectin variability in inflammatory bowel disease. Full text in Research Archive
• Kristensen, Vendel Ailin; Malmstrøm, Gunn; Skar, Viggo Øystein & Moum, Bjørn (2015). Clinical relevance of faecal calprotectin variability in inflammatory bowel disease. Full text in Research Archive
• Kristensen, Vendel Ailin & Moum, Bjørn (2015). Correspondence: Fecal calprotectin and cut-off levels in inflammatory bowel disease. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 50(9), p. 1183–1184. doi: 10.3109/00365521.2015.1025830. Full text in Research Archive

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