Tom Mala

• Reas, Deborah; Lie, Selma; Mala, Tom & Kvalem, Ingela Lundin (2026). Maladaptive Weight-Related Compensatory Behaviours Among Individuals Undergoing Metabolic and Bariatric Surgery. European Eating Disorders Review. ISSN 1072-4133. doi: 10.1002/erv.70181. Full text in Research Archive
• Edholm, David; Kauppila, Joonas H.; Achiam, Michael P.; Kempf, Oliver Nørholm; Hauge, Tobias & Lindblad, Mats [Show all 7 contributors for this article] (2026). Incidence of lymph node metastases in pT1 chemo- and radiotherapy-naïve esophageal and gastric cancer in the Nordic countries: a retrospective multinational cohort analysis. Diseases of the esophagus. ISSN 1120-8694. 39(5), p. 1–9. doi: 10.1093/dote/doag105. Full text in Research Archive
• Fasting, Magnus Hølmo; Joys, Ulrik; Førland, Dag T.; Skagemo, Caroline Ursin; Hauge, Tobias & Johnson, Egil [Show all 7 contributors for this article] (2026). Robotic-assisted versus laparoscopic gastrectomy in a low-incidence Nordic country: A single-center retrospective study. Scandinavian Journal of Surgery. ISSN 1457-4969. doi: 10.1177/14574969261480875. Full text in Research Archive
• Hauge, Tobias; Johnson, Egil; Aahlin, Eirik Kjus; Øvrebø, Kjell Kåre; Than, Tien Pham & Rekstad, Lars cato [Show all 7 contributors for this article] (2026). Textbook outcome after esophagectomy in Norway–a national cohort study of low- to medium-volume centers. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. doi: 10.1080/00365521.2026.2694746. Full text in Research Archive
• Haug, Helene Marie; Risstad, Hilde; Hagen, Rolf Eikeland; Mala, Tom; Kristinsson, Jon Adalsteinn & Søvik, Torgeir Thorson (2026). Weight Loss, Comorbidity, and Complications After Single-anastomosis Sleeve Ileal Bypass (SASI): A Systematic Review and Meta-analysis. Obesity Surgery. ISSN 0960-8923. doi: 10.1007/s11695-026-08793-0. Full text in Research Archive
• Treider, Martin; Kienlin, Simone Maria; Fyhn, Thomas Johan; Glomsaker, Tom Birger; Fasting, Magnus Hølmo & Kasper, Jürgen [Show all 7 contributors for this article] (2026). Shared decision-making in the treatment of uncomplicated gallstone disease: A cross-sectional pilot study. Scandinavian Journal of Surgery. ISSN 1457-4969. 115(2), p. 169–176. doi: 10.1177/14574969261419688. Full text in Research Archive
• Chahal-Kummen, Monica; Hewitt, Stephen I; Søvik, Torgeir Thorson; Kristinsson, Jon Adalsteinn & Mala, Tom (2026). Metabolic Outcomes and Recurrent Weight Gain 10 Years After Roux-en-Y Gastric Bypass, a Longitudinal Cohort Study. Obesity Surgery. ISSN 0960-8923. doi: 10.1007/s11695-026-08662-w. Full text in Research Archive Show summary

  Introduction Long-term weight loss and improvement in associated medical problems are seen after metabolic bariatric surgery (MBS) as Roux-en-Y gastric bypass (RYGB). Few studies have focused on recurrent weight gain (RWG) after RYGB. Methods Patients operated with RYGB from 2004 to 2008 were invited to 10-year follow-up consultations. The primary outcome was weight development in terms of total weight loss and RWG. Significant RWG was defined as gaining > 30% of initial weight loss two years postoperatively. Secondary outcomes included associated medical problems. Results Among a total of 582 patients operated, 311/544 (56%) patients attended 10-year follow-up. Mean age at 10 years was 52.8 (9.2) years, with 76.5% females. Body mass index (BMI), weight and total weight loss at 10-year follow-up were 35.6 (6.8) kg/m2, 103.7 (24.1) kg and 23.4 (12.3) %, respectively. RWG at 10-year follow-up was 26.0 (48.8) %, with 45.6% of the patients experiencing RWG > 30%. For patients with and without RWG > 30%, the relapse and remission rates of diabetes type 2 and hypertension were comparable. Relapse rates of dyslipidemia were higher in patients with RWG > 30%. Conclusion We found a high prevalence of significant RWG 10 years after RYGB. Except for dyslipidemia, the metabolic benefits of RYGB persisted despite RWG.

• Buer, Liliana; Kvalem, Ingela Lundin & Mala, Tom (2026). Bariatric Surgery and Gender Differences in Depressive Symptoms—A 5-Year Prospective Study of Preoperative Predictors. Obesity Science & Practice. 12(2). doi: 10.1002/osp4.70120. Full text in Research Archive
• Salte, Odd Bjørn; Hagen, Rolf Eikeland; Svanevik, Marius; Fagerland, Morten; Risstad, Hilde & Hjelmesæth, Jøran Sture [Show all 9 contributors for this article] (2026). Effect of standard versus long alimentary limb distal Roux-en-Y gastric bypass on weight loss and nutritional outcomes at 10 years in patients with BMI 50–60 kg/m2—a secondary analysis of a randomized clinical trial. British Journal of Surgery. ISSN 0007-1323. 113(1). doi: 10.1093/bjs/znaf285. Full text in Research Archive Show summary

  Abstract Objective Identifying the optimal metabolic bariatric surgery approach for patients with severe obesity with a BMI ≥50 kg/m2 remains challenging. The aim of this long-term follow-up of a randomized clinical trial (RCT) was to compare distal long alimentary limb Roux-en-Y gastric bypass (RYGB) with standard RYGB for 10-year weight loss and nutritional outcomes. Method Secondary analysis of a 10-year follow-up of an RCT with initially 113 patients (BMI 50–60 kg/m2) randomized to either standard (n = 57, 50 cm biliopancreatic/150 cm alimentary limb) or distal long alimentary limb RYGB (n = 56, 50 cm biliopancreatic/150 cm common limb) from March 2011 to April 2013 at two Norwegian hospitals. The final data collection date was 15 August 2023. The primary focus was weight loss (BMI reduction, %total weight loss) and other secondary outcomes included cardiometabolic risk factors, nutritional status, and health-related quality of life (HRQOL). Results Of 113 patients, 79 (69.9%, mean age 50 (s.d. 8.7) years, 50 (63%) females) patients were available for 10-year follow-up (41 standard RYGB, 38 distal RYGB). The 10-year mortality rate was 3.5% (4/113) and all deaths occurred after distal RYGB. One death may have been associated with the surgery in a patient with previously undiagnosed liver cirrhosis at the time of operation. Mean BMI reduction from baseline was 12.0 kg/m2 (95% c.i., 10.8 to 13.2) after standard RYGB and 14.7 kg/m2 (95% c.i., 13.5 to 15.9) after distal RYGB with a between-group difference of 2.7 kg/m2 (95% c.i., 1.0 to 4.5, P = 0.002). The mean percentage total weight loss from baseline was 23.0% (95% c.i., 20.8 to 25.2) after standard RYGB and 28.2% (95% c.i., 26.0 to 30.5) after distal RYGB, with a between-group difference of 5.3% (95% c.i., 2.1 to 8.4, P = 0.001). The distal RYGB group had higher rates of malnutrition (1/57 standard versus 5/56 distal; P = 0.12), diarrhoea (7/57 standard versus 15/56 distal; P = 0.05), and vitamin D deficiency (24/41 standard versus 32/38 distal; P = 0.01). There were no differences between the groups in the prevalence of type 2 diabetes, hypertension, dyslipidaemia, or metabolic syndrome at 10-year follow-up. Four patients underwent revisional surgery due to malnutrition after distal RYGB. There were no statistically significant differences in HRQOL scores between the groups at 10 years (SF-36 physical 44.2 versus 44.1, mental 50.3 versus 47.3; OWLQOL 63 versus 61; all P > 0.2). Conclusions Distal long alimentary limb RYGB resulted in greater weight loss after 10 years with a higher risk of malnutrition, diarrhoea, and vitamin D deficiency. Trial Registration Clinicaltrials.gov NCT00821197

• Sundgot-Borgen, Christine; Bårdstu, Silje Kvam; Bond, D. S.; Sniehotta, F. F.; Bergh, Irmelin & Mala, Tom [Show all 8 contributors for this article] (2025). Longitudinal associations between self-regulation and physical activity behavior following metabolic bariatric surgery; an exploratory study. International Journal of Behavioral Nutrition and Physical Activity. 22. doi: 10.1186/s12966-025-01739-2. Full text in Research Archive Show summary

  Background Low adherence to moderate-to-vigorous physical activity (MVPA) recommendations among patients undergoing metabolic bariatric surgery (MBS) is common. However, understanding of psychosocial factors that contribute to low adherence levels is limited. Self-regulation plays a key role in MVPA adherence. Still, the longitudinal and bidirectional associations between self-regulation and MVPA in the MBS patient population remains unexplored. This study aimed to investigate how self-regulatory processes of action- and coping planning, and action control, developed over a 1–5-year post-surgery period, and explore longitudinally the direct, indirect, and bidirectional associations between this development in self-regulation and MVPA assessed at 1- and 5-years after surgery. Methods Participants from the Oslo Bariatric Surgery Study (OBSS) completed MVPA-specific self-regulation questionnaires at 1-, 3-, and 5-years post-surgery and wore ActiGraph monitors for seven days at 1- and 5-years to assess daily MVPA. Second-order latent growth curve modeling examined changes in the three self-regulation constructs, followed by path analysis to explore direct, indirect, and bidirectional associations between baseline levels and changes in self-regulation, and MVPA at 1- and 5-years post-surgery. Results A total of 205 (82.8%), 195 (64.6%), and 79 (26.2%) male and females (77%) participated at 1-, 3-, and 5-years after surgery, respectively. Action- and coping- planning decreased with.52 and.30 sd, respectively, over 1–5 years post-surgery. This indicates a moderate effect size. Action control remained relatively stable. Indirect and bidirectional path analyses showed that only higher levels of action control at 1-year were indirectly associated with higher MVPA at 5-years through their impact on MVPA at 1-year, whereas there were no indications of bidirectional associations from MVPA levels at 1-year to changes in any of the self-regulation constructs over time. Conclusions After MBS, patients exhibited low self-regulation 1-year post-surgery, and many participants faced growing difficulties in self-regulating over time. Self-regulation at 1-year was positively linked to MVPA, with action control only, being associated with MVPA at 5-years. However, no bidirectional associations from MVPA to self-regulation were found. These findings suggest further research is needed to test interventions targeting action control to improve MVPA adherence and optimize surgical outcomes and overall health after MBS.

• Hedberg, Jakob; Kauppila, Joonas; Aahlin, Eirik Kjus; Edholm, David; Johnsen, Gjermund & Johansson, Jan [Show all 21 contributors for this article] (2025). Nasogastric tube after oesophagectomy and risk of anastomotic leak: a Nordic, multicentre, open-label, randomised, controlled, non-inferiority trial. The Lancet Regional Health - Europe. 57. doi: 10.1016/j.lanepe.2025.101411. Full text in Research Archive Show summary

  Background Oesophagectomy, a corner stone in curative treatment of oesophageal cancer, is a complex procedure with high complication rates. Postoperative gastric tube decompression is debated and some centres are abandoning routine nasogastric (NG) tube use. We hypothesised that postoperative NG tube removal is non-inferior to five days of NG tube decompression, with regard to the risk of anastomotic leak. Methods In this open-label, non-inferiority randomised controlled trial across 12 hospitals in Sweden, Norway, Denmark and Finland, participants treated for oesophageal or gastroesophageal junctional cancer with oesophagectomy were randomly assigned (1:1) to no postoperative NG tube or five days of NG tube decompression. Anastomotic leak was the primary outcome and secondary outcomes included pneumonia and length of hospital stay. Analyses were performed on the intention to treat and per protocol populations and non-inferiority for anastomotic leak was defined as a risk difference below 9%. ISRCTN.com registration ISRCTN39935085. Findings Between January 1st 2022 and March 27th 2024, 448 patients were randomly assigned, 217 to no postoperative NG tube and 231 to five days NG tube treatment. The mean age was 67.5 (standard deviation (SD) 9.8) years and 367 (81.9%) were males. Non-inferiority with regard to anastomotic leak for no NG tube decompression could not be shown with 48 patients (22.1% (95% confidence interval (CI) 16.8%, 28.2%)) having anastomotic leak compared to 35 (15.2% (95% CI 10.8%, 20.4%)) with five days of NG tube decompression, a risk difference of −7.0% (95% CI −14.4%, 0.00%), pnon-inferiority 0.30. In a Supplementary analysis, patients had a lower risk of anastomotic leak if postoperative NG decompression was used. Rate of other complications, e.g., pneumonia, were similar between groups. In a per-protocol analysis, the risk difference was −11.3% to the advantage of NG tube (95% CI, −19.1, −0.3%). Interpretation We could not establish safety (increased risk of anastomotic leak) and therefore do not support omission of NG tube after oesophagectomy. Funding This trial was funded by the Swedish Cancer Society and the Nordic Cancer Union.

• Hauge, Tobias; Johnson, Egil; Fasting, Magnus Hølmo; Førland, Dag T.; Skagemo, Caroline Ursin & Mala, Tom (2025). From conventional minimally invasive to robotic-assisted Ivor Lewis esophagectomy – A Nordic single-center retrospective study. European Journal of Surgical Oncology. ISSN 0748-7983. 51(11). doi: 10.1016/j.ejso.2025.110417. Full text in Research Archive Show summary

  Background High-quality studies from Asia have demonstrated that robotic assisted minimally invasive esophagectomy (RAMIE) is a feasible and comparable alternative to conventional minimally invasive esophagectomy (MIE), evidence regarding its application to Western patients remains limited. This study evaluates the short-term outcomes during the initial phase of RAMIE implementation in comparison to the previous standard MIE technique in a Nordic center. Methods A retrospective single center study of prospectively registered data, comparing short-term outcomes between the final 100 patients operated with MIE and the first 100 patients operated with RAMIE. The primary outcome was the total number of lymph nodes harvested. Secondary outcomes included postoperative pneumonia, anastomotic leakage, serious complications (Clavien Dindo 3), length of operation, length of hospital stay and resection margin status. An inverse probability weighting model and regression analysis was conducted. Results 200 patients were included (RAMIE n = 100, MIE n = 100). Matched groups (RAMIE n = 96, MIE n = 97) showed no difference in total number of lymph nodes harvested (RAMIE 22.1 vs. MIE 23.7, p = 0.50). RAMIE had higher postoperative pneumonia risk (OR = 2.3, p < 0.01), longer length of operation (+33.9 min, p < 0.01) and marginally increased risk of anastomotic leakage (OR = 2.4, p = 0.05). Comparing the last 50 patients operated with RAMIE to the MIE group, there was no difference in length of operation (OR = 10.3, p = 0.43). Conclusion The short-term oncological outcomes and safety remain secure even during the initial phases of RAMIE implementation in a Nordic cohort. The perioperative outcome for some measures after RAMIE were inferior to MIE, potentially related to learning curve aspects.

• Pinto, Rita Isabel Morais; Sjurgard, Ingrid Vikan; Pharo, Heidi; Mala, Tom; Vedeld, Hege Marie & Lind, Guro Elisabeth (2025). Molecular stratification of esophageal adenocarcinoma: implications for prognosis and treatment strategy. Oncogene. ISSN 0950-9232. 45, p. 353–367. doi: 10.1038/s41388-025-03650-3. Full text in Research Archive Show summary

  Genome-wide molecular profiling has emerged as a promising approach for advancing the clinical management of esophageal adenocarcinoma (EAC), with the potential to improve prognostic accuracy and enable more personalized treatment strategies. In this review, we summarize current evidence from genomic and epigenomic EAC stratification studies, highlighting the proposed molecular subtypes and evaluating their clinical relevance. We discuss how these subclassifications may inform disease outcomes, refine patient selection for specific therapies and uncover new treatment opportunities aligned with tumor molecular profiles. Additionally, we explore molecular subtypes associated with Barrett’s esophagus, a precursor lesion of EAC, and consider how these insights can help elucidate the mechanisms underlying EAC development. Such understanding may inform improved strategies for early tumor detection, risk stratification and prevention, ultimately aiming to reduce the burden of EAC. We also address the current challenges limiting the clinical application of these molecular classifiers, including restricted sample availability, insufficient validation and the difficulty of translating genome-wide findings into practical and clinical useful biomarkers. Integrating molecular subtyping into clinical workflows is a key step toward precision medicine in EAC, with the goal of enhancing treatment response rates and patient outcomes. Future advances will require collaborative efforts and robust clinical validation in large prospective studies to ensure that molecular stratification strategies can be effectively translated into improved management of EAC.

• Svensson, Stina Ingrid Alice; Saeed, Sadia; Hoffmann, Anne; Ghosh, Adhideb; Wolfrum, Christian & Dahl, Mai Britt [Show all 15 contributors for this article] (2025). HOOK1 Gene Expression and DNA Methylation in Obesity and Related Cardiometabolic Traits. Obesity Facts. ISSN 1662-4025. doi: 10.1159/000547603. Full text in Research Archive Show summary

  Introduction: Accumulation of fat in omental visceral adipose tissue (OVAT) is strongly linked to metabolic diseases. Our recent findings show a distinct and more accessible chromatin landscape of the visceral depot compared to its subcutaneous counterpart. Based on integrated analysis of chromatin accessibility and transcriptomics, we identified previously unrecognised genes linked with obesity. Here, we performed in-depth analyses of one of the candidates, HOOK1, and tested for depot-specific gene expression, correlation with clinical traits and regulatory mechanisms including DNA methylation. Methods: We utilised intra-individually paired adipose tissue samples of human OVAT and subcutaneous adipose tissue (SAT) from our in-house cohort (N = 78). Gene expression was measured using real-time quantitative PCR and pyrosequencing was used to determine DNA methylation levels. Data were analysed for differential gene expression and DNA methylation differences between SAT and OVAT, along with correlation analyses with clinical variables related to obesity. Results were validated in adipose tissue samples from 1,618 donors of the Leipzig Obesity Biobank. Results: We observed consistently higher HOOK1 gene expression in OVAT compared to SAT and successfully confirmed this effect direction in several validation cohorts. We further identified that HOOK1 gene expression correlated with body mass index and hip circumference. We discovered a relationship between DNA methylation of the HOOK1 promoter with clinical variables important for liver function. Conclusion: Our data show that HOOK1 gene expression is adipose tissue depot-specific. We observed that gene expression and DNA methylation are correlated to clinical variables of obesity, suggesting that HOOK1 may play a role in obesity and its sequelae.

• Saeed, Sadia; Hoffmann, Anne; Svensson, Stina Ingrid Alice; Visnovska, Martina; Hagemann, Tobias & Ghosh, Adhideb [Show all 13 contributors for this article] (2025). Integrative analysis of gene expression and histone modifications for DES, DSP, GJA1 and SMOC2 in adipose tissue reveals potential relationship to cardiometabolic health. Molecular medicine (Cambridge, Mass. Print). ISSN 1076-1551. 31. doi: 10.1186/s10020-025-01391-3. Full text in Research Archive Show summary

  Abstract Background Adipose tissue influences cardiometabolic health through its endocrine activity and its role in regulating inflammation, lipid metabolism, and cardiovascular function. The expression of cardiac-associated genes within adipose tissue may reflect or contribute to cardiometabolic risk, yet this relationship remains poorly understood. This study investigates the expression profiles of the cardiac function associated genes GJA1 , DES , DSP and SMOC2 in human adipose tissue, and analyses their associations with cardiometabolic traits. Additionally, we explore epigenomic mechanisms that may underlie their differential gene expression. Methods Expression profiling and functional enrichment analyses were conducted to identify depot-specific cardiac gene expression patterns. Quantitative PCR validated gene expression in paired subcutaneous (SAT) and omental visceral adipose tissue (OVAT) samples from 78 individuals with obesity. Gene expression was further validated in three independent cohorts ( N  = 1,548 total). Associations with clinical traits were assessed using Spearman correlations and multivariate linear regression, adjusted for age, sex, and BMI. Integration with transcriptomic and proteomic datasets publicly available from the Adipose Tissue Knowledge Portal was performed to strengthen clinical relevance. Epigenomic profiling using genome-wide ChIP-seq for histone marks (H3K4me3, H3K4me1, H3K27ac, H3K27me3) was conducted in paired SAT and OVAT samples from five individuals. Results DES , DSP , GJA1 , and SMOC2 were significantly upregulated in OVAT compared to SAT. DES , DSP , and SMOC2 showed consistent expression patterns across all cohorts, while GJA1 exhibited context-dependent regulation. Gene expression in SAT was negatively correlated with cardiometabolic traits, including blood pressure, insulin resistance, and liver function markers. These associations were confirmed by regression analysis and supported by publicly available multi-omics data. Epigenetic analyses revealed OVAT-specific enrichment of active histone marks and reduced repressive marks, supporting higher differential transcriptional activity in OVAT. Conclusions Depot-specific gene expression of DES , DSP , and SMOC2 in adipose tissue is robustly linked to cardiometabolic traits and supported by distinct epigenetic landscapes in OVAT vs SAT, highlighting their potential as novel biomarkers for cardiometabolic health.

• Rønningen, Torunn; Zeng, Yong; Dahl, Mai Britt; Wang, Junbai; Visnovska, Martina & Tannæs, Tone Møller [Show all 18 contributors for this article] (2025). Global mapping of RNA N6-methyladenosine (m6A) in human subcutaneous and visceral adipose tissue reveals novel targets that correlate with clinical variables of obesity. Biomarker Research. 13(1). doi: 10.1186/s40364-025-00857-0. Full text in Research Archive Show summary

  Abstract Background Obesity is a major health challenge and fat accumulation in visceral depots is more strongly associated with metabolic comorbidities than deposition in subcutaneous depots. Epitranscriptomic regulation of gene expression by N 6 -methyladenosine (m 6 A) influences various aspects of RNA metabolism, however the m 6 A methylome in human adipose tissue and its relationship with fat distribution has not yet been investigated in detail. Methods In this study, we performed epitranscriptomic mapping of m 6 A in intra-individually paired samples of subcutaneous (SAT) and omental visceral adipose tissue (OVAT) from women with normal weight (BMI ≤25, n  = 3) and obesity (BMI ≥35, n  = 10) using meRIP-seq (discovery cohort). We further investigated differential m 6 A methylation for specific target genes in a larger cohort of individuals with obesity ( n  = 72, validation cohort) using meRIP-qPCR. meRIP-seq was performed for primary adipocytes from a subset of the patients ( n  = 4) to account for cell type specific differences. Results We here provide the first global map of m 6 A in human adipose tissue in paired samples of SAT and OVAT. We show an overall high overlap in m 6 A sites between individuals and depots, but also distinct depot-specific differences. We identify 339 target genes showing depot-specific m 6 A methylation. Depot-specific methylation was validated for selected sites in SEMA3A , SNAP47 and PPP1R9A in a larger validation cohort. We additionally identify differentially methylated targets between lean individuals and individuals with obesity, including TSC22D1 , FMNL2 and IL1R1 . By combining data from primary adipocytes with data from corresponding bulk adipose tissue, we identified a higher number of genes containing m 6 A in non-adipocyte cells in OVAT compared to SAT. Mechanistically, we show for selected targets that m 6 A affects RNA lifetime in pre-adipocyte cell culture models. Importantly, m 6 A methylation in selected targets correlates with clinically important variables related to obesity, fat distribution and glucose metabolism. Conclusions We identify a catalogue of novel targets showing adipose tissue depot specific m 6 A methylation, with potential as biomarkers in metabolic disease. Our findings underscore the regulatory role of m 6 A in obesity and provide valuable insights for future research. The datasets generated represent a significant resource for further insight in adipose tissue biology and its implications for metabolic health.

• Saeed, Sadia; Poulsen, Lars La Cour; Visnovska, Martina; Hoffmann, Anne; Ghosh, Adhideb & Wolfrum, Christian [Show all 18 contributors for this article] (2025). Chromatin landscape in paired human visceral and subcutaneous adipose tissue and its impact on clinical variables in obesity. EBioMedicine. 114. doi: 10.1016/j.ebiom.2025.105653. Full text in Research Archive Show summary

  Background Obesity is a global health challenge and adipose tissue exhibits distinct depot-specific characteristics impacting differentially on the risk of metabolic comorbidities. Methods Here, we integrate chromatin accessibility (ATAC-seq) and gene expression (RNA-seq) data from intra-individually paired human subcutaneous (SAT) and omental visceral adipose tissue (OVAT) samples to unveil depot-specific regulatory mechanisms. Findings We identified twice as many depot-specific differentially accessible regions (DARs) in OVAT compared to SAT. SAT-specific regions showed enrichment for adipose tissue enhancers involving genes controlling extracellular matrix organization and metabolic processes. In contrast, OVAT-specific regions showed enrichment in promoters linked to genes associated with cardiomyopathies. Moreover, OVAT-specific regions were enriched for bivalent transcription start site and repressive chromatin states, suggesting a “lingering” regulatory state. Motif analysis identified CTCF and BACH1 as most significantly enriched motifs in SAT and OVAT-specific DARs, respectively. Distinct gene sets correlated with important clinical variables of obesity, fat distribution measures, as well as insulin, glucose, and lipid metabolism. Interpretation We provide an integrated analysis of chromatin accessibility and transcriptional profiles in paired human SAT and OVAT samples, offering new insights into the regulatory landscape of adipose tissue and highlighting depot-specific mechanisms in obesity pathogenesis.

• Aune, Dagfinn; Nordsletten, Marie Wiborg; Myklebust, Tor Åge; Robsahm, Trude Eid; Skålhegg, Bjørn Steen & Mala, Tom [Show all 8 contributors for this article] (2025). Body mass index and risk of Hodgkin's lymphoma: Insights from a Norwegian cohort study. European Journal of Cancer. ISSN 0959-8049. 221. doi: 10.1016/j.ejca.2025.115400. Full text in Research Archive Show summary

  Background Several studies have reported positive associations between higher body mass index (BMI) and risk of Hodgkin's lymphoma. However, the evidence is not entirely consistent. We investigated the association between BMI and Hodgkin's lymphoma in a large Norwegian cohort with up to 50 years follow-up. Methods The analytical dataset included 1723,692 men and women aged 16–75 years at baseline in 1963–1975. Multivariable Cox regression analyses were used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for the associations between BMI and Hodgkin's lymphoma incidence. Results During 56.1 million person-years of follow-up, 1608 incident Hodgkin's lymphoma cases occurred. Compared to individuals with BMI 18.5-< 25, the HRs (95 % CIs) for those with a BMI of 15-< 18.5, 25-< 30, and ≥ 30 were 0.87 (0.59–1.27), 1.05 (0.94–1.18), and 1.61 (1.35–1.91), respectively, and 1.57 (1.30–1.90) and 1.80 (1.24–2.62) for obesity grade 1 and grade 2, respectively. A positive association was also observed per 5 kg/m2 increment with a HR (95 % CI) of 1.16 (1.08–1.24) overall, 1.20 (1.09–1.31) in women, and 1.08 (0.96–1.20) in men. Positive associations were also observed between obesity vs. normal weight in early adulthood (age 16–29 years) and Hodgkin's lymphoma (HR, 95 % CIs: 1.89, 1.10–3.22, ptrend<0.0001, n = 489 cases) and between obesity and early-onset (age <50 years at diagnosis) disease (HR, 95 % CIs: 1.67, 1.01–2.78, ptrend<0.0001, n = 393 cases). Conclusion The positive associations observed between higher BMI overall and in young adulthood and Hodgkin's lymphoma and between BMI and early-onset disease emphasize the potential role of adiposity in development of this malignancy.

• Aune, Dagfinn; Nordsletten, Marie Wiborg; Myklebust, Tor Åge; Robsahm, Trude Eid; Skålhegg, Bjørn Steen & Mala, Tom [Show all 8 contributors for this article] (2025). Body mass index and risk of connective and soft tissue cancer: results from a large cohort of 1.7 million individuals in Norway. BMC Cancer. 25. doi: 10.1186/s12885-025-13637-8. Full text in Research Archive Show summary

  Background Few studies have investigated the association between adiposity and connective and soft tissue cancer, a rare and understudied cancer entity. We investigated this association in a large cohort of more than 1.7 million individuals in Norway. Methods The study cohort included 1,723,692 men and women aged 16–75 years at baseline in 1963–1975. Data on weight and height measurements from the Norwegian Tuberculosis Screening Programme were linked to the Cancer Registry. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between body mass index (BMI) and risk of connective and soft tissue cancer, adjusting for age and sex. Results In total 1758 connective and soft tissue cancer cases were registered during 56.1 million person-years of follow-up. The HRs (95% CIs) for the BMI categories of 15-<18.5, 18.5-<25.0 (reference), 25.0-<30.0, 30.0-<35.0, ≥ 35.0 were 0.77 (0.50–1.20), 1.00 (reference), 1.15 (1.03–1.27), 1.28 (1.06–1.54), and 1.69 (1.21–2.37, ptrend<0.0001). The HR per 5 kg/m2 increment in BMI was 1.14 (1.07–1.22) overall, 1.10 (0.99–1.23) in men and 1.17 (1.08–1.27) in women. Obesity in early adulthood (age 16–29 years) showed a suggestive positive association with connective and soft tissue cancer risk with HR (95%CIs) of 1.73 (0.95–3.16), ptrend=0.09) when compared to normal weight. No clear association was observed between BMI and early-onset (age < 50 years at diagnosis) connective and soft tissue cancer. Positive associations were observed between BMI and soft tissue sarcoma, fibrosarcoma, dermatofibroma, and lipoleiomyoma, but no clear associations were observed with fibrous histiocytoma and liposarcoma. Conclusion These results suggest that higher BMI overall and in early adulthood may be associated with increased risk of connective and soft tissue cancer, but BMI seems not to influence early-onset disease. Large cohort studies with more detailed information on confounding factors and BMI trajectories over time are needed for further verification before firm conclusions can be made.

• Aune, Dagfinn; Nordsletten, Marie Wiborg; Myklebust, Tor Åge; Robsahm, Trude Eid; Skålhegg, Bjørn Steen & Mala, Tom [Show all 8 contributors for this article] (2025). Body mass index and ampulla of Vater cancer incidence and survival: a cohort study of 1.7 million Norwegians. Hepatobiliary surgery and nutrition. ISSN 2304-3881. p. 1–8. doi: 10.21037/hbsn-2024-636. Full text in Research Archive Show summary

  Background: Although higher body mass index (BMI) has been associated with increased risk of hepatobiliary cancers in previous studies, the association with risk of ampulla of Vater cancer has rarely been reported. We therefore investigated the association between BMI and ampulla of Vater cancer incidence in a large Norwegian cohort. Methods: The analytical dataset included 1,723,692 men and women aged 16–75 years at baseline in 1963– 1975. Multivariable Cox regression analyses were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between BMI and ampulla of Vater cancer incidence and survival. Results: During 56.1 million person-years of follow-up, a total of 814 cases with ampulla of Vater cancer were identified. Compared to participants with a BMI of 18.5–<25 kg/m2, the HRs (95% CIs) of those with a BMI of 15–<18.5, 25–<30, and ≥30 kg/m2 were 0.19 (0.05–0.77), 1.02 (0.88–1.19), and 1.03 (0.80–1.32), respectively, and 1.02 (0.92–1.12) per 5 kg/m2 increment. No association was observed in men and women, when analysed separately. The HRs (95% CIs) for BMI in young adulthood were 0.39 (0.10–1.57), 1.00, 1.26 (0.80–1.99), and 3.62 (1.76–7.48, Ptrend=0.004) for a BMI of 15–<18.5, 18.5–<25.0, 25–<30, and ≥30 kg/m2, and 1.61 (1.25–2.06) per 5 kg/m2 increment (n=130), and for early-onset ampulla of Vater cancer (n=19) was 1.00, 2.10 (0.75–5.88), and 5.45 (1.16–25.70, Ptrend=0.01), and 1.91 (1.10–3.32) per 5 kg/m2 increment. Higher BMI was not clearly associated with cancer-specific survival among ampulla of Vater cancer patients (HR 1.19, 95% CI: 0.89–1.61 for BMI ≥30 vs. 18.5–<25.0 kg/m2). Conclusions: Overall, the results show no clear association between higher BMI and ampulla of Vater cancer incidence or survival. However, strong positive associations were observed between BMI in young adulthood and risk of ampulla of Vater cancer and between BMI and early-onset diagnosis. Further studies are needed to verify these findings.

• Saeed, Usman; Myklebust, Tor Åge; Robsahm, Trude Eid; Aune, Dagfinn; Møller, Bjørn & Skålhegg, Bjørn Steen [Show all 8 contributors for this article] (2025). Associations between body mass index and gastroesophageal cancer incidence and mortality: novel insights from a nationwide registry-based cohort study. Diseases of the esophagus. ISSN 1120-8694. 38(2). doi: 10.1093/dote/doaf018. Full text in Research Archive Show summary

  The association between body mass index (BMI) and cancers of the esophagus and the stomach remains complex and requires further exploration. This study aimed to investigate this association, including early-onset (< 50 years) cancer and cancer related mortality. A nationwide registry-based cohort study was performed by linking data from multiple national registries in Norway. The cohort included 1,723,692 individuals, with 22,473 gastroesophageal cancer cases identified over 55,701,169 person-years of follow-up. In men, a 5 kg/m2 increase in BMI was associated with an increased risk of esophageal (HR 1.34, 95%CI 1.22–1.48) and cardia adenocarcinoma (HR 1.36, 95% CI, 1.22–1.50). This finding extended to individuals with high BMI in early life (16–29 years) for esophageal adenocarcinoma. The highest risk per 5 kg/m2 increase in BMI was observed for early-onset esophageal (HR 2.49, 95%CI 1.23–5.02) and cardia adenocarcinoma (HR 2.26, 95%CI 1.19–4.27). Among women, increased BMI was associated with a higher risk of both esophageal (HR 1.28, 95%CI 1.13–1.44) and gastric adenocarcinoma (HR 1.04, 95%CI 1.01–1.07). Women with elevated BMI in early life also demonstrated increased risk for these cancers. In both sexes, a 5 kg/m2 increase in BMI was inversely associated with squamous cell carcinoma of the esophagus. No association was observed between BMI and risk of cancer-related mortality. This study highlights an elevated risk of gastroesophageal adenocarcinomas with increasing BMI, with notable sex, age, and site-specific variations. The findings also point to a heightened risk of early-onset esophageal and cardia adenocarcinoma in men with high BMI.

• Lie, Selma; Reas, Deborah; Mala, Tom & Kvalem, Ingela Lundin (2025). Food Addiction 5 and 10 Years Following Metabolic and Bariatric Surgery: a Prospective Observational Study. Obesity Surgery. ISSN 0960-8923. 35, p. 1649–1656. doi: 10.1007/s11695-025-07803-x. Full text in Research Archive Show summary

  Background Food addiction (FA) is prevalent among individuals undergoing metabolic and bariatric surgery (MBS), but few studies have investigated the prevalence and correlates of post-surgical FA over longer periods. We report an observational, longitudinal study investigating prevalence of post-surgical FA at 5 and 10 years following MBS. Methods Participants in the Oslo Bariatric Surgery Study (OBSS) completed the modified Yale Food Addiction Scale 2.0 (mYFAS) and measures of psychological functioning and weight outcomes (% total weight loss: %TWL and % weight recurrence: %WR) at 5 and 10 years follow-up. Results N = 173 of 224 (23% lost-to-follow-up) participants (73% women, 93.6% Roux-en-Y gastric bypass) completed the mYFAS 2.0 at 5 years and 10 years following MBS. The prevalence of FA was 12.9% at 5 years and 8.4% at 10 years after MBS. A higher number of FA symptoms at 5 years significantly predicted less %TWL and lower psychological functioning at 10 years. At 10 years, the majority of individuals with FA had moderate or severe symptoms and 3% were new-onset cases of FA. Higher FA at 10 years was concurrently associated with less %TWL, greater %WR, and lower psychological functioning at the 10-year follow-up (p’s < 0.001). Conclusions The prevalence of FA decreased from 12.9 to 8.4% between 5 and 10 years following MBS. We observed prospective and concurrent associations between FA symptoms and poorer weight loss and mental health outcomes. The presence of post-operative FA may be an important target for continued assessment and follow-up care to improve longer-term outcomes.

• Aune, Dagfinn; Mala, Tom; Myklebust, Tor Åge; Nordsletten, Marie Wiborg; Robsahm, Trude Eid & Saeed, Usman [Show all 8 contributors for this article] (2024). The association between body mass index and vulvar and vaginal cancer incidence: findings from a large Norwegian cohort study | Cancer Causes & Control. Cancer Causes and Control. ISSN 0957-5243. 36(2), p. 191–198. doi: 10.1007/s10552-024-01930-z. Full text in Research Archive Show summary

  There is limited evidence of potential associations between body mass index (BMI) and risk of vulvar and vaginal cancer. We explored these associations in a large cohort of Norwegian women. The analytical dataset included 889,441 women aged 16–75&nbsp;years at baseline in 1963–1975. Multivariable Cox regression analyses were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between BMI and vulvar and vaginal cancer incidence. During 30.1 million person-years of follow-up, 1748 incident vulvar and 408 incident vaginal cancer cases occurred. The HRs (95% CIs) for vulvar cancer for a BMI of 15- &lt; 18.5, 18.5- &lt; 25, 25- &lt; 30, 30- &lt; 35, ≥ 35 were 0.62 (0.38–1.01), 1.00 (reference), 1.23 (1.10–1.40), 1.43 (1.23–1.66) and 1.72 (1.35–2.20, ptrend &lt; 0.001), and per 5&nbsp;kg/m2 increment was 1.20 (1.13–1.26). The corresponding HRs (95% CIs) for vaginal cancer were 1.05 (0.52–2.15), 1.00, 0.89 (0.71–1.12), 0.95 (0.68–1.34), and 2.01 (1.29–3.13, ptrend &lt; 0.001), respectively, and per 5&nbsp;kg/m2 was 1.11 (0.99–1.25). The HR (95% CI) per 5&nbsp;kg/m2 increase in BMI at ages 16–29 was 1.28 (1.07–1.54, n = 250 cases) for vulvar and 1.53 (1.11–2.11, n = 66 cases) for vaginal cancers. The HR (95% CI) per 5&nbsp;kg/m2 for early-onset (&lt; 50&nbsp;years age at diagnosis) vulvar cancer was 0.92 (0.66–1.28, n = 87 cases) and 1.70 (1.05–2.76, n = 21 cases) for vaginal cancer. These results further support the associations between higher BMI and increased risk of vulvar and vaginal cancers, with suggestive stronger associations between BMI in early adulthood for both cancers and for early-onset vaginal cancer. Further studies are needed to elucidate these findings and investigate the underlying mechanisms.

• Heieren, Ole Einar; Mala, Tom; Viktil, Ellen; Grøtta, Ole Jørgen & Woldbæk, Per R (2024). Radiologisk behandling av lymfelekkasje. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 144(5). doi: 10.4045/tidsskr.24.0039. Full text in Research Archive
• Høibråten, Jesper; Borg, Eirik; Søvik, Torgeir Thorson; Mala, Tom & Fasting, Magnus Hølmo (2024). Revisional surgery at the esophageal hiatus—a Scandinavian single-center retrospective review of 59 operations. Annals of Esophagus. ISSN 2616-2784. doi: 10.21037/aoe-24-21. Full text in Research Archive
• Thomassen, Henrik Krossøy; Kilander, Fredrik Sandve; Mala, Tom; Glomsaker, Terje & Fasting, Magnus Hølmo (2024). Laparoskopisk transcystisk ekstraksjon av gallegangskonkrementer. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 144(7). doi: 10.4045/tidsskr.23.0823. Full text in Research Archive
• Saeed, Usman; Yakub, Sheraz; Barreto, Savio G.; Pandol, Stephen & Mala, Tom (2024). Reducing the risk of cancer with bariatric surgery: The need for evidence to guide practice. Scandinavian Journal of Surgery. ISSN 1457-4969. p. 263–335. doi: 10.1177/14574969241264064. Full text in Research Archive
• Aune, Dagfinn; Nordsletten, Marie Wiborg; Myklebust, Tor Åge; Robsahm, Trude Eid; Skålhegg, Bjørn Steen & Mala, Tom [Show all 8 contributors for this article] (2024). The association between body mass index and vulvar and vaginal cancer incidence: findings from a large Norwegian cohort study. Cancer Causes and Control. ISSN 0957-5243. 36, p. 191–198. doi: 10.1007/s10552-024-01930-z. Full text in Research Archive Show summary

  Background There is limited evidence of potential associations between body mass index (BMI) and risk of vulvar and vaginal cancer. We explored these associations in a large cohort of Norwegian women. Methods The analytical dataset included 889,441 women aged 16–75 years at baseline in 1963–1975. Multivariable Cox regression analyses were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between BMI and vulvar and vaginal cancer incidence. Results During 30.1 million person-years of follow-up, 1748 incident vulvar and 408 incident vaginal cancer cases occurred. The HRs (95% CIs) for vulvar cancer for a BMI of 15- < 18.5, 18.5- < 25, 25- < 30, 30- < 35, ≥ 35 were 0.62 (0.38–1.01), 1.00 (reference), 1.23 (1.10–1.40), 1.43 (1.23–1.66) and 1.72 (1.35–2.20, ptrend < 0.001), and per 5 kg/m2 increment was 1.20 (1.13–1.26). The corresponding HRs (95% CIs) for vaginal cancer were 1.05 (0.52–2.15), 1.00, 0.89 (0.71–1.12), 0.95 (0.68–1.34), and 2.01 (1.29–3.13, ptrend < 0.001), respectively, and per 5 kg/m2 was 1.11 (0.99–1.25). The HR (95% CI) per 5 kg/m2 increase in BMI at ages 16–29 was 1.28 (1.07–1.54, n = 250 cases) for vulvar and 1.53 (1.11–2.11, n = 66 cases) for vaginal cancers. The HR (95% CI) per 5 kg/m2 for early-onset (< 50 years age at diagnosis) vulvar cancer was 0.92 (0.66–1.28, n = 87 cases) and 1.70 (1.05–2.76, n = 21 cases) for vaginal cancer. Conclusion These results further support the associations between higher BMI and increased risk of vulvar and vaginal cancers, with suggestive stronger associations between BMI in early adulthood for both cancers and for early-onset vaginal cancer. Further studies are needed to elucidate these findings and investigate the underlying mechanisms.

• Salte, Odd Bjørn; Olbers, Torsten; Risstad, Hilde; Fagerland, Morten; Søvik, Torgeir Thorson & Høgestøl, Ingvild Kristine [Show all 9 contributors for this article] (2024). Ten-Year Outcomes Following Roux-en-Y Gastric Bypass vs Duodenal Switch for High Body Mass Index: A Randomized Clinical Trial. JAMA Network Open. 7(6). doi: 10.1001/jamanetworkopen.2024.14340. Full text in Research Archive Show summary

  Importance Results from long-term follow-up after biliopancreatic diversion with duodenal switch (DS) are scarce. Objective To compare weight loss, health outcomes, and quality of life 10 years or more after Roux-en-Y-gastric bypass (RYGB) and DS surgery in patients with severe obesity—that is, a body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 50 to 60. Design, Setting, and Participants This open-label randomized clinical trial was conducted at 2 academic bariatric centers in Sweden and Norway. Sixty patients with a BMI of 50 to 60 were included from March 1, 2006, to August 31, 2007. Data were analyzed from August 12, 2022, to January 25, 2023. Interventions Laparoscopic RYGB or laparoscopic DS. Main Outcomes and Measures The main outcome was change in BMI after 10 or more years. Secondary outcomes included anthropometric measures, lipid and glycemic profiles, bone mass density, adverse events, gastrointestinal tract symptoms, and health-related quality of life. Results Forty-eight of the original 60 patients (80%) were assessed after a median of 12 (range, 9-13) years (mean [SD] age, 48.0 [6.0] years; 35 women [73%]). At follow-up, the mean BMI reductions were 11.0 (95% CI, 8.3-13.7) for RYGB and 20.3 (95% CI, 17.6-23.0) for DS, with a mean between-group difference of 9.3 (95% CI, 5.4-13.1; P < .001). Total weight loss was 20.0% (95% CI, 15.3%-24.7%) for RYGB and 33.9% (95% CI, 27.8%-40.0%) for DS (P = .001). Mean serum lipid levels, except high-density lipoprotein cholesterol and hemoglobin A1c, improved more in the DS group during follow-up. Bone mass was reduced for both groups from 5 to 10 years, with lower bone mass after DS at 10 years. Quality-of-life scores (Obesity-Related Problem Scale and the 36-Item Short Form Health Survey) were comparable across groups at 10 years. The total number of adverse events was higher after DS (135 vs 97 for RYGB; P = .02). More patients in the DS group developed vitamin deficiencies (21 vs 11 for RYGB; P = .008) including 25-hydroxyvitamin D deficiency (19 for DS vs 9 for RYGB; P = .005). Four of 29 patients in the DS group (14%) developed severe protein-caloric malnutrition, of whom 3 (10%) underwent revisional surgery. Conclusions and Relevance In this randomized clinical trial, BMI reduction was greater after DS, but RYGB had a better risk profile over 10 years. Biliopancreatic diversion with DS may not be a better surgical strategy than RYGB for patients with a BMI of 50 to 60.

• Hauge, Tobias; Dretvik, Thomas Bruvoll; Johnson, Egil & Mala, Tom (2024). Treatment of anastomotic leakage following Ivor Lewis esophagectomy-10 year experience from a Nordic center. Diseases of the esophagus. ISSN 1120-8694. 37(9). doi: 10.1093/dote/doae040. Full text in Research Archive Show summary

  Anastomotic leakage (AL) is a dreaded complication following esophageal resection. No clear consensus exist for the optimal handling of this severe complication. The aim of this study was to describe the treatment outcome following AL. We conducted a retrospective cross-sectional study including all patients with AL operated with Ivor Lewis esophagectomy from 2010 to 2021 at Oslo University Hospital, Norway. 74/526 (14%) patients had AL. Patient outcomes were analyzed and categorized according to main AL treatment strategy; stent (54%), endoscopic vacuum therapy and stent (EVT + stent) (19%), nasogastric tube and antibiotics (conservative) (16%), EVT (8%) and by other endoscopic means (other) (3%). One patient had surgical debridement of the chest cavity. In 66 patients (89%), the perforation healed after median 27 (range: 4–174) days. Airway fistulation was observed in 11 patients (15%). Leak severity (ECCG) was associated with development of airway fistula (P = 0.03). The median hospital and intensive care unit stays were 30 (range: 12–285) and 9 (range: 0–60) days. The 90-days mortality among patients with AL was 5% and at follow up, 13% of all deaths were related to AL. AL closure rates were comparable across the groups, but longer in the EVT + stent group (55 days vs. 29.5 days, P = 0.04). Thirty-two percent developed a symptomatic anastomotic stricture within 12 months. Conclusion: The majority of AL can be treated endoscopically with preservation of the conduit and the anastomosis. We observed a high number of AL-associated airway fistulas.

• Aune, Dagfinn; Nordsletten, Marie Wiborg; Myklebust, Tor Åge; Robsahm, Trude Eid; Skålhegg, Bjørn Steen & Mala, Tom [Show all 8 contributors for this article] (2024). Body mass index and penile cancer incidence: results from a Norwegian cohort study of 829,081 men. BMC Urology. 24(1), p. 1–6. doi: 10.1186/s12894-024-01636-z. Full text in Research Archive Show summary

  Background A few previous studies have suggested a possible association between adiposity and increased risk of penile cancer, however, the evidence is to date limited for this rare cancer. We investigated the association between body mass index (BMI) and penile cancer risk in a large Norwegian cohort. Methods The analyses included 829,081 men aged 16–75 years at baseline in 1963–1975. Multivariable Cox regression analyses were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between BMI and penile cancer incidence. Results A total of 725 incident penile cancer cases occurred during 25.6 million person-years of follow-up. Compared to men with BMI 18.5-<25, the HRs (95% CIs) of those with a BMI of 15-<18.5, 25-<30, and ≥ 30 were 0.45 (0.15–1.41), 1.14 (0.97–1.33) and 1.63 (1.20–2.22), respectively, and the HR was 1.26 (1.12–1.42) per 5 kg/m2 increase in BMI. When the obese category was further subdivided in grade 1 (BMI 30-<35) and grade 2 obesity (≥ 35), the respe

• Reas, Deborah L.; Lie, Selma Øverland; Mala, Tom & Kvalem, Ingela Lundin (2024). Binge Eating Behaviour Before and 10 Years Following Metabolic and Bariatric Surgery. European Eating Disorders Review. ISSN 1072-4133. doi: 10.1002/erv.3161. Full text in Research Archive
• McPhail, Sean; Barclay, Matthew E; Johnson, Shane A; Swann, Ruth; Alvi, Riaz & Barisic, Andriana [Show all 34 contributors for this article] (2024). Use of chemotherapy in patients with oesophageal, stomach, colon, rectal, liver, pancreatic, lung, and ovarian cancer: an International Cancer Benchmarking Partnership (ICBP) population-based study. The Lancet Oncology. ISSN 1470-2045. 25(3), p. 338–351. doi: 10.1016/S1470-2045(24)00031-7. Full text in Research Archive Show summary

  Background There are few data on international variation in chemotherapy use, despite it being a key treatment type for some patients with cancer. Here, we aimed to examine the presence and size of such variation. Methods This population-based study used data from Norway, the four UK nations (England, Northern Ireland, Scotland, and Wales), eight Canadian provinces (Alberta, British Columbia, Manitoba, Newfoundland and Labrador, Nova Scotia, Ontario, Prince Edward Island, and Saskatchewan), and two Australian states (New South Wales and Victoria). Patients aged 15–99 years diagnosed with cancer in eight different sites (oesophageal, stomach, colon, rectal, liver, pancreatic, lung, or ovarian cancer), with no other primary cancer diagnosis occurring from within the 5 years before to 1 year after the index cancer diagnosis or during the study period were included in the study. We examined variation in chemotherapy use from 31 days before to 365 days after diagnosis and time to its initiation, alongside related variation in patient group differences. Information was obtained from cancer registry records linked to clinical or patient management system data or hospital administration data. Random-effects meta-analyses quantified interjurisdictional variation using 95% prediction intervals (95% PIs). Findings Between Jan 1, 2012, and Dec 31, 2017, of 893 461 patients with a new diagnosis of one of the studied cancers, 111 569 (12·5%) did not meet the inclusion criteria, and 781 892 were included in the analysis. There was large interjurisdictional variation in chemotherapy use for all studied cancers, with wide 95% PIs: 47·5 to 81·2 (pooled estimate 66·4%) for ovarian cancer, 34·9 to 59·8 (47·2%) for oesophageal cancer, 22·3 to 62·3 (40·8%) for rectal cancer, 25·7 to 55·5 (39·6%) for stomach cancer, 17·2 to 56·3 (34·1%) for pancreatic cancer, 17·9 to 49·0 (31·4%) for lung cancer, 18·6 to 43·8 (29·7%) for colon cancer, and 3·5 to 50·7 (16·1%) for liver cancer. For patients with stage 3 colon cancer, the interjurisdictional variation was greater than that for all patients with colon cancer (95% PI 38·5 to 78·4; 60·1%). Patients aged 85–99 years had 20-times lower odds of chemotherapy use than those aged 65–74 years, with very large interjurisdictional variation in this age difference (odds ratio 0·05; 95% PI 0·01 to 0·19). There was large variation in median time to first chemotherapy (from diagnosis date) by cancer site, with substantial interjurisdictional variation, particularly for rectal cancer (95% PI –15·5 to 193·9 days; pooled estimate 89·2 days). Patients aged 85–99 years had slightly shorter median time to first chemotherapy compared with those aged 65–74 years, consistently between jurisdictions (–3·7 days, 95% PI –7·6 to 0·1). Interpretation Large variation in use and time to chemotherapy initiation were observed between the participating jurisdictions, alongside large and variable age group differences in chemotherapy use. To guide efforts to improve patient outcomes, the underlying reasons for these patterns need to be established. Funding International Cancer Benchmarking Partnership (funded by the Canadian Partnership Against Cancer, Cancer Council Victoria, Cancer Institute New South Wales, Cancer Research UK, Danish Cancer Society, National Cancer Registry Ireland, The Cancer Society of New Zealand, National Health Service England, Norwegian Cancer Society, Public Health Agency Northern Ireland on behalf of the Northern Ireland Cancer Registry, DG Health and Social Care Scottish Government, Western Australia Department of Health, and Public Health Wales NHS Trust).

• Jannicke, Heramb-Aamot; Mala, Tom & Fauske, Lena (2024). Everyday Life Six to Eight Months After Esophagectomy for Cancer: A Qualitative Study. Anticancer Research. ISSN 0250-7005. 44(2), p. 743–750. doi: 10.21873/anticanres.16865. Full text in Research Archive
• Kooij, Cezanne D.; Jongh, Cas de; Kingma, B. Feike; Henegouwen, Mark I. van Berge; Gisbertz, Suzanne S. & Chao, Yin-Kai [Show all 44 contributors for this article] (2024). The Current State of Robot-Assisted Minimally Invasive Esophagectomy (RAMIE): Outcomes from the Upper GI International Robotic Association (UGIRA) Esophageal Registry. Annals of Surgical Oncology. ISSN 1068-9265. 32, p. 823–833. doi: 10.1245/s10434-024-16364-9. Full text in Research Archive Show summary

  Background Robot-assisted minimally invasive esophagectomy (RAMIE) is increasingly adopted in centers worldwide, with ongoing refinements to enhance results. This study aims to assess the current state of RAMIE worldwide and to identify potential areas for improvement. Methods This descriptive study analyzed prospective data from esophageal cancer patients who underwent transthoracic RAMIE in Upper GI International Robotic Association (UGIRA) centers. Main endpoints included textbook outcome rate, surgical techniques, and perioperative outcomes. Analyses were performed separately for intrathoracic (Ivor–Lewis) and cervical anastomosis (McKeown), divided into three time cohorts (2016–2018, 2019–2020, 2021–2023). A sensitivity analysis was conducted with cases after the learning curve (> 70 cases). Results Across 28 UGIRA centers, 2012 Ivor–Lewis and 1180 McKeown procedures were performed. Over the time cohorts, textbook outcome rates were 39%, 48%, and 49% for Ivor–Lewis, and 49%, 63%, and 61% for McKeown procedures, respectively. Fully robotic procedures accounted for 66%, 51%, and 60% of Ivor–Lewis procedures, and 53%, 81%, and 66% of McKeown procedures. Lymph node yield showed 27, 30, and 30 nodes in Ivor–Lewis procedures, and 26, 26, and 34 nodes in McKeown procedures. Furthermore, high mediastinal lymphadenectomy was performed in 65%, 43%, and 37%, and 70%, 48%, and 64% of Ivor–Lewis and McKeown procedures, respectively. Anastomotic leakage rates were 22%, 22%, and 16% in Ivor–Lewis cases, and 14%, 12%, and 11% in McKeown cases. Hospital stay was 13, 14, and 13 days for Ivor–Lewis procedures, and 12, 9, and 11 days for McKeown procedures. In Ivor–Lewis and McKeown, respectively, the sensitivity analysis revealed textbook outcome rates of 43%, 54%, and 51%, and 47%, 64%, and 64%; anastomotic leakage rates of 28%, 18%, and 15%, and 13%, 11%, and 10%; and hospital stay of 11, 12, and 12 days, and 10, 9, and 9 days. Conclusions This study demonstrates favorable outcomes over time in achieving textbook outcome after RAMIE. Areas for improvement include a reduction of anastomotic leakage and shortening of hospital stay.

• Lyyjynen, Hannu Sakari; Andersen, John Roger; Liem, Ronald S. L.; Mala, Tom; Nienhuijs, Simon W. & Ottosson, Johan [Show all 9 contributors for this article] (2024). Surgical Aspects of Sleeve Gastrectomy Are Related to Weight Loss and Gastro-esophageal Reflux Symptoms. Obesity Surgery. ISSN 0960-8923. 34, p. 902–910. doi: 10.1007/s11695-023-07018-y. Full text in Research Archive Show summary

  Introduction A large variation in outcome has been reported after sleeve gastrectomy (SG) across countries and institutions. We aimed to evaluate the effect of surgical technique on total weight loss (TWL) and gastro-esophageal reflux disease (GERD). Methods Observational cohort study based on data from the national registries for bariatric surgery in the Netherlands, Norway, and Sweden. A retrospective analysis of prospectively obtained data from surgeries during 2015–2017 was performed based on 2-year follow-up. GERD was defined as continuous use of acid-reducing medication. The relationship between TWL, de novo GERD and operation technical variables were analyzed with regression methods. Results A total of 5927 patients were included. The average TWL was 25.6% in Sweden, 28.6% in the Netherlands, and 30.6% in Norway (p < 0.001 pairwise). Bougie size, distance from the resection line to the pylorus and the angle of His differed between hospitals. A minimized sleeve increased the expected total weight loss by 5–10 percentage points. Reducing the distance to the angle of His from 3 to just above 0 cm increased the risk of de novo GERD five-fold (from 3.5 to 17.8%). Conclusion Smaller bougie size, a shorter distance to pylorus and to the angle of His were all associated with greater weight loss, whereas a shorter distance to angle of His was associated with more de novo reflux.

• Saeed, Usman; Nordsletten, Marie Wiborg; Myklebust, Tor Åge; Robsahm, Trude Eid; Møller, Bjørn & Skålhegg, Bjørn Steen [Show all 8 contributors for this article] (2023). Cancer risk and survival according to body mass index in hepatobiliary malignancies: a nationwide registry-based cohort study. HPB. ISSN 1365-182X. 25(11), p. 1382–1392. doi: 10.1016/j.hpb.2023.07.882. Full text in Research Archive Show summary

  Background The aim of this study was to explore the associations between BMI and cancer of the liver, bile ducts, and gallbladder. Methods A registry-based cohort study was performed by linking data from several national registries in Norway. Results The cohort comprised 1 723 692 individuals including 4768 hepatobiliary cancer cases during 55 743 509 person-years of follow-up. In men, we found increased risk of cancer per 5 kg/m2 BMI increase for hepatocellular carcinoma and extrahepatic cholangiocarcinoma. In women there was increased risk of extrahepatic cholangiocarcinoma and gallbladder cancer. Women with high BMI in early adulthood had increased risk of intrahepatic cholangiocarcinoma. Reduced cancer-specific survival was found for all hepatobiliary malignancies in women with overweight and obesity. In men, reduced survival was observed in individuals with obesity for all hepatobiliary cancers, except gallbladder cancer. Increased risk of cancer-death per 5 kg/m2 BMI increase was found for hepatocellular carcinoma, intra-, and extrahepatic cholangiocarcinoma in women. For men, 5 kg/m2 BMI increase was positively associated with cancer-death from intrahepatic cholangiocarcinoma. Discussion This study supports the notion of an increased risk of hepatobiliary cancers with increasing BMI, with sex and age variations. The findings also suggest a higher risk of cancer-death with increasing BMI.

• Borgen, Christine Sundgot; Bond, D.S.; Sniehotta, F.F.; Kvalem, Ingela Lundin; Hansen, Bjørge Hermann & Bergh, Irmelin [Show all 8 contributors for this article] (2023). Associations of changes in physical activity and sedentary time with weight recurrence after bariatric surgery: a 5-year prospective study. International Journal of Obesity. ISSN 0307-0565. 47, p. 463–470. doi: 10.1038/s41366-023-01284-7. Full text in Research Archive Show summary

  Background Increasing physical activity and limiting sedentary time may minimize weight recurrence after bariatric surgery. However, few studies have evaluated potential associations of objectively-measured physical activity and sedentary time with post-surgical weight recurrence over time. Aims To evaluate associations of change in physical activity and sedentary time with weight recurrence after bariatric surgery. Methods Participants from the Oslo Bariatric Surgery Study, a prospective cohort study, wore an ActiGraph monitor for seven days at 1- and 5 years after surgery to assess daily physical activity and sedentary time. Participants’ weight was measured at in-person clinic visits. Chi-square Test and Paired-samples T-test evaluated group differences and change over time, while Pearson’s Correlation, multiple logistic and linear regression investigated associations between variables. Results Five years after surgery 79 participants (70.5% response rate, 81% female) (mean (sd) age: 54.0 (±9.3), BMI: 32.1 (±4.7)) had valid monitor data. Participants increased their sedentary time (71.4 minutes/day (95% CI: 54.2–88.6, p = <0.001)) and reduced daily steps (−1411.1 (95% CI: 737.8–208.4), p = <0.001), light physical activity (−54.1 min/day (95% CI: 40.9–67.2, p = <0.001)), and total physical activity (−48.2 (95% CI: 34.6–63.3), p = <0.001) from 1- to 5 years after surgery. No change was found for moderate-to-vigorous intensity physical activity. No associations were found between changes in steps, physical activity or sedentary time and weight recurrence. Conclusion Participants increased sedentary time and decreased light- and total physical activity between 1- and 5 years post-surgery. Overall, changes in physical activity and sedentary time were not associated with weight recurrence. Interventions to help patients increase physical activity and limit sedentary time after bariatric surgery are needed.

• Kazaryan, Airazat M.; Monrad-Hansen, Peter Wiel; Eftang, Lars Lohne; Hagve, Martin Iversen; Nedrebø, Bjørn Gunnar & RANCINGER, PETER IVAN [Show all 7 contributors for this article] (2023). Perioperativ antibiotika-profylakse og intervall appendektomi. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 143(7). doi: 10.4045/tidsskr.23.0282. Full text in Research Archive
• Høgestøl, Ingvild Kristine; Aasbrenn, Martin; Kvalem, Ingela Lundin; Eribe, Inger; Kristinsson, Jon Adalsteinn & Mala, Tom (2023). Pain sensitivity after Roux-en-Y gastric bypass - Associations with chronic abdominal pain and psychosocial aspects. Scandinavian Journal of Pain. ISSN 1877-8860. 23(3), p. 511–517. doi: 10.1515/sjpain-2023-0005. Full text in Research Archive Show summary

  Objectives The aims of this study were to investigate modifications in pain sensitivity after RYGB and to explore associations between pain sensitivity and weight loss, chronic abdominal pain, total body pain, anxiety, depression, and pain catastrophizing. Methods In total, 163 patients with obesity were examined with a cold pressor test for pain sensitivity before and two years after RYGB. Two aspects of pain sensitivity were registered: Pain intensity (numeric rating scale, range 0–10) and pain tolerance (seconds). Associations between pain sensitivity and the explanatory variables were assessed with linear regression. Results Two years after RYGB the pain intensity increased (mean ± SD 0.64 ± 1.9 score units, p<0.001). Pain tolerance decreased (7.2 ± 32.4 s, p=0.005). A larger reduction in body mass index was associated with increased pain intensity, β=−0.090 (95 % CI −0.15 to −0.031, p=0.003), and decreased pain tolerance β=1.1 (95 % CI 0.95 to 2.2, p=0.03). Before surgery, participants with chronic abdominal pain reported 1.2 ± 0.5 higher pain intensity (p=0.02) and had 19.2 ± 9.3 s lower pain tolerance (p=0.04) than those without abdominal pain. No differences in pain sensitivity were observed between participants who did or did not develop chronic abdominal pain after RYGB. Pain sensitivity was associated with symptoms of anxiety but not with pain catastrophizing, depression or bodily pain. Conclusions The pain sensitivity increased after RYGB and was associated with larger weight loss and anxiety symptoms. Changes in pain sensitivity were not associated with development of chronic abdominal pain after RYGB in our study.

• jongh, cas de; Cianchi, Fabio; Kinoshita, Takahiro; Kingma, Feike; Piccoli, Micaela & Dubzec, Attila [Show all 33 contributors for this article] (2023). Surgical techniques and related perioperative outcome after robot-assisted minimally invasive gastrectomy (RAMIG): Results from the prospective multicenter international Ugira Gastric Registry. Annals of Surgery. ISSN 0003-4932. 280(1), p. 98–107. doi: 10.1097/SLA.0000000000006147. Full text in Research Archive Show summary

  Objective: To gain insight into the global practice of robot-assisted minimally invasive gastrectomy (RAMIG) and evaluate perioperative outcomes using an international registry. Background: The techniques and perioperative outcomes of RAMIG for gastric cancer vary substantially in the literature. Methods: Prospectively registered RAMIG cases for gastric cancer (≥10 per center) were extracted from 25 centers in Europe, Asia, and South-America. Techniques for resection, reconstruction, anastomosis, and lymphadenectomy were analyzed and related to perioperative surgical and oncological outcomes. Complications were uniformly defined by the Gastrectomy Complications Consensus Group. Results: Between 2020 and 2023, 759 patients underwent total (n=272), distal (n=465), or proximal (n=22) gastrectomy (RAMIG). After total gastrectomy with Roux-en-Y-reconstruction, anastomotic leakage rates were 8% with hand-sewn (n=9/111) and 6% with linear stapled anastomoses (n=6/100). After distal gastrectomy with Roux-en-Y (67%) or Billroth-II-reconstruction (31%), anastomotic leakage rates were 3% with linear stapled (n=11/433) and 0% with hand-sewn anastomoses (n=0/26). Extent of lymphadenectomy consisted of D1+ (28%), D2 (59%), or D2+ (12%). Median nodal harvest yielded 31 nodes (interquartile range: 21–47) after total and 34 nodes (interquartile range: 24–47) after distal gastrectomy. R0 resection rates were 93% after total and 96% distal gastrectomy. The hospital stay was 9 days after total and distal gastrectomy, and was median 3 days shorter without perianastomotic drains versus routine drain placement. Postoperative 30-day mortality was 1%. Conclusions: This large multicenter study provided a worldwide overview of current RAMIG techniques and their respective perioperative outcomes. These outcomes demonstrated high surgical quality, set a quality standard for RAMIG, and can be considered an international reference for surgical standardization.

• Mala, Tom & Aahlin, Eirik Kjus (2023). Stepping up the management of anastomotic leaks after oesophagectomy: getting a feel through less invasive tentacles. British Journal of Surgery. ISSN 0007-1323. 110(8), p. 877–879. doi: 10.1093/bjs/znad142. Full text in Research Archive
• Richardsen, Andrea J.; Chahal-Kummen, Monica; Kristinsson, Jon Adalsteinn; Søvik, Torgeir Thorson; Eribe, Inger & Mala, Tom (2023). Gastrisk bypass med én anastomose ved sykelig overvekt. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 143(16), p. 1–11. doi: 10.4045/tidsskr.23.0070. Full text in Research Archive Show summary

  BAKGRUNN Mini-gastrisk bypass er en ny kirurgisk metode i behandlingen av sykelig overvekt. Metoden ble innført ved Oslo universitetssykehus i 2016. MATERIALE OG METODE Vi utførte en retrospektiv analyse av prospektivt innsamlede data med to års oppfølging etter mini-gastrisk bypass i perioden 1.3.2016–1.4.2021. RESULTATER Totalt 241/1 611 (15 %) pasienter operert ved Senter for sykelig overvekt i femårsperioden ble operert med mini-gastrisk bypass. 147/241 (61 %) oppfylte inklusjonskriteriene, og 125/147 (85 %) ble inkludert i studien. Gjennomsnittsalderen var 47,4 år (standardavvik 10,7), 81/125 (64,8 %) var kvinner. Gjennomsnittsvekt var 134 (25) kg før og 90 (20) kg etter operasjon. Totalt gjennomsnittlig vekttap to år etter kirurgi var 33,1 % (9,1). Før kirurgi og to år etter hadde henholdsvis 20,0 % og 27,2 % gastroøsofageal refluks, 38,3 % og 8,8 % diabetes type 2 og 84,8 % og 44,0 % dyslipidemi. Totalt utviklet 12 % anemi, 6,3 % jernmangel og 23,1 % vitamin D-mangel. Tidlige (< 30 dager) komplikasjoner ble registrert hos 6/125 (4,8 %) pasienter og sene (> 30 dager) hos 7/125 (5,6 %) pasienter. Resultatene var sammenlignbare med alle kvalitetsindikatorene i norsk register for fedmekirurgi. FORTOLKNING Mini-gastrisk bypass kan utføres med få komplikasjoner og med gunstig effekt på følgesykdommer opptil to år etter kirurgi.

• Nordsletten, Marie Wiborg; Saeed, Usman; Myklebust, Tor Åge; Robsahm, Trude Eid; Møller, Bjørn & Skålhegg, Bjørn Steen [Show all 8 contributors for this article] (2023). Body mass index and its association with 22 cancer types: a Norwegian cohort study of 481 202 cancer cases. Acta Oncologica. ISSN 0284-186X. 62(10), p. 1273–1278. doi: 10.1080/0284186X.2023.2258443. Full text in Research Archive
• Fasting, Magnus Hølmo; Strønen, Erlend; Glomsaker, Tom Birger; Søvik, Torgeir Thorson; Fyhn, Thomas Johan & Mala, Tom (2023). Perioperative strategies for patients undergoing subtotal cholecystectomy: a single-center retrospective review of 102 procedures. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. doi: 10.1080/00365521.2023.2289352. Full text in Research Archive
• Chahal-Kummen, Monica; Våge, Villy; Kristinsson, Jon Adalsteinn & Mala, Tom (2023). Chronic abdominal pain and quality of life after Roux-en-Y gastric bypass and sleeve gastrectomy – a cross-cohort analysis of two prospective longitudinal observational studies. Surgery for Obesity and Related Diseases. ISSN 1550-7289. 19, p. 819–829. doi: 10.1016/j.soard.2023.01.020. Full text in Research Archive Show summary

  Background: Chronic abdominal pain (CAP) after bariatric surgery is not extensively explored and may impact the postoperative outcomes. Objective: To compare the prevalence of patient-reported chronic abdominal pain (CAP) after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG). Secondarily, we compared other abdominal and psychological symptoms and quality of life (QoL). Preoperative predictors of postoperative CAP were also explored. Setting: Tertiary referral centers for bariatric surgery in Norway. Methods: Analyses of 2 separate prospective longitudinal cohort studies evaluating CAP, abdominal and psychological symptoms and QoL before and 2 years after RYGB and SG. Results: Follow-ups were attended by 416 patients (85.8%), 300/416 (72.1%) were females and 209/ 416 (50.2%) were RYGB procedures. At follow-up, the mean age was 44.9 (10.0) years, BMI 29.5 (5.4) kg/m2, and total weight loss 31.6 (10.3) %. The prevalence of CAP was 28/236 (11.9%) before and 60/209 (28.7%) after RYGB (P ,.001) and 32/223 (14.3%) before and 50/186 (26.9%) after SG (P,.001). Gastrointestinal symptom rating scale scores showed greater deterioration of diarrhea and indigestion after RYGB and reflux after SG. The improvement in depression symptoms was greater after SG, as well as several QoL scores improved more after SG. Patients with CAP after RYGB experienced deterioration in several QoL scores, while these scores improved in patients with CAP after SG. Preoperative hypertension, bothersome reflux symptoms, and CAP predicted postoperative CAP. Conclusions: The prevalence of CAP increased comparably after RYGB and SG, with worsening of gastroesophageal reflux after SG and greater deterioration of diarrhea and indigestion after RYGB. In patients with CAP at follow-up, several QoL scores improved more after SG than RYGB.

• Saaed, Usman; Myklebust, Tor Åge; Robsahm, Trude Eid; Møller, Bjørn; Mala, Tom & Skålhegg, Bjørn Steen [Show all 7 contributors for this article] (2022). Body mass index and pancreatic adenocarcinoma: A nationwide registry-based cohort study. Scandinavian Journal of Surgery. ISSN 1457-4969. 112(1), p. 11–21. doi: 10.1177/14574969221127530. Full text in Research Archive Show summary

  Background and objective:An association between body mass index (BMI) and pancreatic cancer is suggested in observational studies. However, further studies are required to substantiate available evidence. The aim of this study was to explore the association between BMI and pancreatic ductal adenocarcinoma (PDAC) risk, treatment, and mortality. Methods:A registry-based cohort study was performed by combining data from four registries in Norway. Baseline data were collected between 1963 and 1975 with follow-up data collected until 2018. Kaplan–Meier curves and multivariable Cox regressions were estimated. Chi-square tests were used to analyze differences between groups. Results:The study cohort consisted of 1,723,692 individuals. A total of 8973 PDAC cases were identified during 55,744,749 person-years of follow-up. A 5 kg/m2 increase in BMI was associated with an increased risk of PDAC if high BMI at young age (16–29 years) (hazard ratio (HR): 1.21, 95% confidence interval (CI): 1.13–1.31), both for men (HR: 1.30, 95% CI: 1.15–1.46) and women (HR: 1.16, 95% CI: 1.05–1.28). In men, there was a 52% increase in risk of early-onset PDAC (<age 50) (HR: 1.52, 95% CI: 1.13-2.03) with 5 kg/m2 increase in BMI. A total of 2645 individuals were diagnosed with stage 1–3 disease, of whom 1131 underwent curative surgery. In all, 49% of normal weight, 38% overweight, and 30% obese individuals with stage 1–3 PDAC underwent surgery with curative intent (p < 0.001). Cancer survival was lower in overweight and obese individuals for both sexes. Analysis adjusted for sex, age, and period of diagnosis confirmed increased risk of cancer death in obese individuals. Conclusion:This study suggests that increased BMI in young adults may increase the risk of PDAC, and higher BMI in men is associated with an increased risk of early onset PDAC (<age 50). Overweight and obese individuals were less likely to undergo curative surgery and obese individuals had a higher risk of cancer-related death.

• Pinto, Rita; Hauge, Tobias; Jeanmougin, Marine; Pharo, Heidi Dietrichson; Kresse, Stine Henrichson & Honne, Hilde [Show all 13 contributors for this article] (2022). Targeted genetic and epigenetic profiling of esophageal adenocarcinomas and non-dysplastic Barrett’s esophagus. Clinical Epigenetics. 14(77), p. 1–11. doi: 10.1186/s13148-022-01287-7. Full text in Research Archive Show summary

  Background Despite the efforts to describe the molecular landscape of esophageal adenocarcinoma (EAC) and its precursor lesion Barrett’s esophagus (BE), discrepant findings are reported. Here, we investigated the prevalence of selected genetic (TP53 mutations and microsatellite instability (MSI) status) and epigenetic (DNA promoter hypermethylation of APC, CDKN2A, MGMT, TIMP3 and MLH1) modifications in a series of 19 non-dysplastic BE and 145 EAC samples. Additional biopsies from adjacent normal tissue were also evaluated. State-of-the-art methodologies and well-defined scoring criteria were applied in all molecular analyses. Results Overall, we confirmed frequent TP53 mutations among EAC (28%) in contrast to BE, which harbored no mutations. We demonstrated that MSI and MLH1 promoter hypermethylation are rare events, both in EAC and in BE. Our findings further support that APC, CDKN2A, MGMT and TIMP3 promoter hypermethylation is frequently seen in both lesions (21–89%), as well as in a subset of adjacent normal samples (up to 12%). Conclusions Our study further enlightens the molecular background of BE and EAC. To the best of our knowledge, this is one of the largest studies addressing a targeted analysis of genetic and epigenetic modifications simultaneously across a combined series of non-dysplastic BE and EAC samples.

• Saaed, Usman; Myklebust, Tor Åge; Robsahm, Trude Eid; Kielland, Marlene Fritsch; Møller, Bjørn & Skålhegg, Bjørn Steen [Show all 8 contributors for this article] (2022). Risk and survival in colorectal cancer with increasing body mass index: A nationwide population-based cohort study. Colorectal Disease. ISSN 1462-8910. p. 1–11. doi: 10.1111/codi.16367. Full text in Research Archive Show summary

  Aim: The aim was to explore potential associations between the body mass index (BMI) and the risk of colorectal cancer (CRC), including subsites of the colon, and cancer-specific death. Methods: A registry-based cohort study was conducted with baseline data gathered from the Norwegian Tuberculosis Screening Programme, collected between 1963 and 1975, and linked to follow-up data from the Cancer Registry of Norway and the Norwegian Cause of Death Registry. Cox regression models were used to explore associations between BMI and CRC risk and cancer-specific death. Results: Of 1 723 692 included individuals, 76 616 developed CRC during 55 370 707 person-years of follow-up. In men, a 5 kg/m2 increase in BMI was associated with an increased risk of colon cancer, including both right and left subsites, and rectal cancer. Allowing for nonlinearities, we found a U-shaped association for the right colon and an inverse U-shape for the left colon and rectum cancer. In women, a 5 kg/m2 increase in BMI in early adulthood was associated with increased risk of colon cancer, including both subsites. In women, an increased risk of CRC death with increasing BMI was found for colon cancer. Conclusions: Men of all ages have an increased risk of CRC with increasing BMI, with the highest risk for right-sided colon cancer. An increased risk for colon cancer was also found in women with high BMI in early adulthood. Furthermore, women of all age groups appeared to have an increased risk of CRC death with higher BMI.

• Kvalem, Ingela Lundin; Gabrielsen, Louise; Eribe, Inger; Kristinsson, Jon Adalsteinn & Mala, Tom (2022). Predicting satisfaction with outcome and follow‐up care five years after bariatric surgery: a prospective evaluation. Obesity Science & Practice. 8(5), p. 595–602. doi: 10.1002/osp4.594. Full text in Research Archive Show summary

  Patient satisfaction is viewed as essential for a successful outcome of bariatric surgery. Few studies have explored long-term satisfaction prospectively. This study aimed to examine pre- and post-surgery predictors for satisfaction with follow-up care, and change in outcome satisfaction from one to five years after bariatric surgery. A sample of 210 participants was recruited from a single treatment center. Self-reported and medical record data regarding mental and somatic health, body image, follow-up attendance, and weight loss were obtained before, one year, and five years after surgery. Over 90% of the participants were satisfied with the results and treatment one year after surgery, while 69% had their outcome expectations fulfilled and 62% were satisfied with the follow-up five years after surgery. A shift from initial satisfaction to unfulfillment of expectations was predicted by baseline body dissatisfaction, greater percentage of weight regain after initial weight loss, and more discomfort from somatic symptoms five years after surgery. In addition to symptom discomfort, worry about surgery predicted satisfaction with follow-up care. At five years, one-fifth of those initially satisfied reported that bariatric surgery had failed to meet their expectations. This suggests that outcome expectations related to weight loss, somatic symptoms, and body image need to be addressed both before and after bariatric surgery.

• Buer, Liliana; Kvalem, Ingela Lundin; Bårdstu, Silje Kvam & Mala, Tom (2022). Comparing Bariatric Surgery Patients Who Desire, Have Undergone, or Have No Desire for Body Contouring Surgery: a 5-Year Prospective Study of Body Image and Mental Health. Obesity Surgery. ISSN 0960-8923. 32(9), p. 2952–2959. doi: 10.1007/s11695-022-06117-6. Full text in Research Archive Show summary

  Abstract Purpose: After bariatric surgery, body contouring surgery (BCS) is thought to improve body image, weight loss, and mental health. Many patients desire but do not undergo BCS after bariatric surgery. This patient subset has rarely been studied. The present study compares bariatric surgery patients that, at 5 years after surgery, desires, have undergone or have no desire for BCS regarding pre- and post-surgery body image and mental health, including within-group changes over time. Materials and methods: Data were collected from participants (N = 216) pre-bariatric surgery and at 1- and 5-year post-surgery. Health care providers measured body mass index (BMI). All other data were collected via self-report (questionnaires). Results: At 5-year post-surgery, 30.6% had undergone BCS, 17.1% did not desire it, and 52.3% desired BCS. Patients who subsequently desired BCS scored lower on body satisfaction pre-surgery than the other groups. They also reported less resilience pre-surgery and more depressive symptoms at all times compared to participants with BCS. For five-year post-surgery, patients who desired BCS had lower body satisfaction levels than patients with BCS and were more bothered with excess skin relative to the two other groups. Body satisfaction improved in all three groups from baseline to five years and in most patients with BCS. Mental health improved only in patients with BCS. Conclusion: This study emphasizes the relevance of identifying participants who desire but have not undergone BCS. The study suggests that BCS is associated with improved body image and mental health.

• Mala, Tom; Førland, Dag T.; Skagemo, Caroline Ursin; Glomsaker, Tom Birger; Johannessen, Hans Olaf & Johnson, Egil (2022). Early experience with total robotic D2 gastrectomy in a low incidence region: surgical perspectives. BMC Surgery. 22. doi: 10.1186/s12893-022-01576-1. Full text in Research Archive
• Arnold, Melina; Morgan, Eileen; Bardot, Aude; Rutherford, Mark; Ferlay, Jaques & Little, Alana [Show all 30 contributors for this article] (2021). International variation in oesophageal and gastric cancer survival 2012-2014: differences by histological subtype and stage at diagnosis (an ICBP SURVMARK-2 population-based study). Gut. ISSN 0017-5749. 71(8), p. 1532–1543. doi: 10.1136/gutjnl-2021-325266. Full text in Research Archive
• Mala, T. (2021). Finding the sweet spot in the surgical treatment of diabetes in obesity. British Journal of Surgery. ISSN 0007-1323. 108(9), p. 1011–1013. doi: 10.1093/bjs/znab179. Full text in Research Archive
• Salte, Odd Bjørn; Svanevik, Marius; Risstad, Hilde; Hofsø, Dag; Høgestøl, Ingvild Kristine & Johnson, Line Kristin [Show all 11 contributors for this article] (2021). Standard versus distal Roux-en-Y gastric bypass in patients with BMI 50–60 kg/m2: 5-year outcomes of a double-blind, randomized clinical trial. BJS Open. 5(6), p. 1–9. doi: 10.1093/bjsopen/zrab105. Full text in Research Archive Show summary

  Background The optimal surgical weight loss procedure for patients with a BMI of 50 kg/m2 or more is uncertain. This study compared distal Roux-en-Y gastric bypass (RYGB) with standard RYGB. Methods In this double-blind RCT, patients aged 18–60 years with a BMI of 50–60 kg/m2 were allocated randomly to receive standard (150 cm alimentary, 50 cm biliopancreatic limb) or distal (150 cm common channel, 50 cm biliopancreatic limb) RYGB. The primary outcome (change in BMI at 2 years) has been reported previously. Secondary outcomes 5 years after surgery, such as weight loss, health-related quality of life, and nutritional outcomes are reported. Results Between May 2011 and April 2013, 123 patients were randomized, 113 received an intervention, and 92 attended 5-year follow-up. Mean age was 40 (95 per cent c.i. 38 to 41) years and 73 patients (65 per cent) were women; 57 underwent standard RYGB and 56 distal RYGB. BMI was reduced by 15.1 (95 per cent c.i. 13.9 to 16.2) kg/m2 after standard and 15.7 (14.5 to 16.9) kg/m2 after distal RYGB; the between-group difference was −0.64 (−2.3 to 1.0) kg/m2 (P = 0.447). Total cholesterol, low-density lipoprotein cholesterol, and haemoglobin A1c levels declined more after distal than after standard RYGB. High-density lipoprotein cholesterol levels increased more after standard RYGB. Vitamin A and vitamin D levels were lower after distal RYGB. Changes in bone mineral density, resting metabolic rate, and total energy intake were comparable. Conclusion Distal RYGB did not enable greater weight loss than standard RYGB. Differences in other outcomes favouring distal RYGB may not justify routine use of this procedure in patients with a BMI of 50–60 kg/m2.

• Chahal-Kummen, Monica; Nordahl, Magnus Kamsvåg; Våge, Villy; Høgestøl, Ingvild Kristine; Kristinsson, Jon Adalsteinn & Mala, Tom (2021). A prospective longitudinal study of chronic abdominal pain and symptoms after sleeve gastrectomy. Surgery for Obesity and Related Diseases. ISSN 1550-7289. 17(12), p. 2054–2064. doi: 10.1016/j.soard.2021.07.014. Full text in Research Archive Show summary

  Background Sleeve gastrectomy (SG) is widely applied. Few studies have evaluated patient-reported abdominal symptoms after SG. Objective To evaluate the prevalence of chronic abdominal pain (CAP) and symptom characteristics after SG. Setting Oslo University Hospital and Voss Hospital. Methods We performed a longitudinal prospective cohort study of patients operated on with SG at two tertiary referral centers. For broad assessments of abdominal pain and symptoms, consultations were performed and questionnaires retrieved before and 2 years after SG. The definition of CAP or recurrent abdominal pain lasting for more than 3 months was sustained. Preoperative predictors of CAP were explored. Results Of 249 patients at baseline, 207 (83.1%) had follow-up consultations. Mean preoperative body mass index was 43.9 (6.0) kg/m2, and 181 patients (72.7%) were female. Total weight loss was 31.9% (10.4%). CAP was reported in 32 of 223 patients (14.3%) before and in 50 of 186 patients (26.9%) after SG (P =.002). All mean gastrointestinal symptoms rating scale questionnaire scores increased after SG, and they were higher in patients with CAP. Symptoms of depression decreased but were more prevalent in patients with CAP at follow-up. Most quality-of-life scores increased after SG. However, patients with CAP had lower scores (except for physical functioning). Preoperative bothersome Gastrointestinal Symptom Rating Scale reflux symptoms, study center, and younger age seemed to predict CAP after SG. Conclusion The prevalence of patient-reported CAP increased after SG. Patients reporting CAP had reduced quality-of-life scores.

• Chahal-Kummen, Monica; Salte, Odd Bjørn; Hewitt, Stephen I; Høgestøl, Ingvild Kristine; Risstad, Hilde & Kristinsson, Jon Adalsteinn [Show all 7 contributors for this article] (2020). Health benefits and risks during 10 years after Roux-en-Y gastric bypass. Surgical Endoscopy. ISSN 0930-2794. 34(12), p. 5368–5376. doi: 10.1007/s00464-019-07328-2. Full text in Research Archive Show summary

  Abstract Background Long-term evaluations 10 years after Roux-en-Y gastric bypass (RYGB) are limited. We report the development in weight and cardiovascular risk factors during 10 years after laparoscopic RYGB, with evaluation of gastrointestinal symptoms and quality of life (QoL) at 10-year follow-up. Methods We performed a prospective longitudinal cohort study. Patients operated with laparoscopic RYGB from May 2004 to November 2006 were invited to 10-year follow-up consultations. Gastrointestinal Symptom Rating Scale (GSRS) questionnaire and two QoL questionnaires were used for analyses of gastrointestinal symptoms and QoL. Results A total of 203 patients were operated; nine (4.4%) died during follow-up. Of 194 eligible patients, 124 (63.9%) attended 10-year follow-up consultations. Percent excess weight loss (%EWL) and percent total weight loss (%TWL) at 10 years were 53.0% and 24.1%, respectively. %EWL &gt; 50% was seen in 53.2%. Significant weight regain (≥15%) from 2 to 10 years was seen in 63.3%. Remission rates of type 2 diabetes, dyslipidemia, and hypertension were 56.8%, 46.0%, and 41.4%, respectively. Abdominal operations beyond 30 days after RYGB were reported in 33.9%. Internal hernia and ileus (13.7%) and gallstone-related disease (9.7%) were the most common causes. Vitamin D deficiency (&lt;50nmol/L) was seen in 33.3%. At 10 years, bothersome abdominal pain and indigestion symptoms (GSRS scores ≥3) were reported in 42.9% and 54.0%, respectively, and were associated with low QoL. Conclusion We observed significant weight loss and remission of comorbidities 10 years after RYGB. Significant weight regain occurred in a substantial subset of patients. Gastrointestinal symptoms were common and negatively impacted QoL.

• Sellevoll, Hilde Bastøe; Saeed, Usman; Young, Victoria Solveig; Sandbæk, Gunnar; Mala, Tom & Gundersen, Karsten (2020). Covid-19 med akutte magesmerter som debutsymptom. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 140(7). doi: 10.4045/TIDSSKR.20.0262. Full text in Research Archive
• Kvalem, Ingela Lundin; Bårdstu, Silje Kvam; Bergh, Irmelin; Nordvik, Thomas; Sogg, Stephanie & Mala, Tom (2020). Associations between perceived somatic symptoms and mental health after Roux-en-Y gastric bypass: a 3-year prospective cohort study. Surgery for Obesity and Related Diseases. ISSN 1550-7289. p. 1–7. doi: 10.1016/j.soard.2019.12.018. Full text in Research Archive Show summary

  Background Attention to and interpretation of symptoms are influenced by psychologic and contextual factors. Preoperative anxiety, and to some extent depression, has been found to predict the perceived impact of somatic symptoms 1 year after Roux-en-Y gastric bypass. Postoperative changes in negative affect may possibly both influence and be influenced by the perception of somatic symptoms. Objectives This study aimed to explore whether preoperative anxiety and depressive symptoms correlated with perceived impact of somatic symptoms 3 years after Roux-en-Y gastric bypass. Second, we aimed to examine the 3-year trajectory of depressive and anxiety symptoms, and their interaction with perceived somatic symptoms postoperatively. Setting University hospital. Methods Presurgery, 1-, and 3-year postsurgery data were collected from 169 participants (62.4% follow-up). Anxiety and depressive symptoms were assessed at all time points. The participants reported the degree of perceived impact of various somatic symptoms 1 and 3 years after surgery. A cross-lagged, autoregressive regression analysis was employed to examine the mutual interaction of trajectories over the follow-up period. Results Fatigue (30.8%) and dumping (23.7%) were common high-impact symptoms 3 years postoperatively. Higher baseline anxiety was associated with higher impact of fatigue, pain, and diarrhea, while depressive mood was related to higher impact of diarrhea at 3-year follow-up. Higher anxiety/depression symptoms were bidirectionally related to higher perceived total symptom impact at both 1 and 3 years postoperatively, controlling for percent total weight loss. Higher perceived impact of somatic symptom burden at 1 year after surgery predicted a significant increase in depressive symptoms the next 2 years. Conclusion Baseline anxiety was associated with higher perceived impact of several somatic symptoms 3 years after Roux-en-Y gastric bypass. Higher total symptom burden (pain, fatigue, dumping, diarrhea, and vomiting) at 1 year after surgery predicted increase in depression over the next 2 years. The results underscore the importance of managing somatic symptoms after surgery to prevent patients’ distress.

• Safi, Nathkai; Johannessen, Hans Olaf; Medhus, Asle Wilhelm; Mala, Tom & Kazmi, Syed Sajid Hussain (2020). Laser doppler flowmetry and visible light spectroscopy of the gastric tube during minimally invasive esophagectomy. Vascular Health and Risk Management. ISSN 1176-6344. 16, p. 497–505. doi: 10.2147/VHRM.S269138. Full text in Research Archive Show summary

  Introduction: Ischemia is considered as the main reason for thoracic gastroesophageal anastomotic leaks after esophagectomy. Microcirculatory monitoring with laser Doppler flowmetry and visible light spectroscopy may provide valuable intraoperative real-time information about the gastric tube’s tissue perfusion and circulation. Patients and Methods: Ten patients with esophageal cancer operated with minimally invasive esophagectomy participated in this single-center, prospective, observational pilot study. A single probe with laser Doppler flowmetry and visible light spectroscopy was used to perform transserosal microcirculation assessment of the gastric tube at predefined anatomical sites during different operation phases. Group comparison and changes were evaluated using the paired sample t-test. Results: A reduction in StO2 was found at all measuring sites after the gastric tube formation compared with the baseline measurements. The mean StO2 reduction from baseline to gastric tube formation and after anastomosis was 16% (range 4%– 28%) and 42% (range, 35%– 52%), respectively. A statistically significant increase in the rHb concentration, representing venous congestion, was detected at the most cranial part of the gastric tube (P = 0.04). Three patients developed anastomotic leaks. Conclusion: Intraoperative real-time laser Doppler flowmetry and visible light spectroscopy are feasible and may provide insight to microcirculatory changes in the gastric tube and at the anastomotic site. Patients with anastomotic leaks seem to have critical local tissue StO2 reduction and venous congestion that should be further evaluated in studies with larger sample sizes.

• Tønnesen, Christer Julseth; Young, Juliet; Glomsaker, Tom Birger; Mala, Tom; Løberg, Magnus & Bretthauer, Michael [Show all 8 contributors for this article] (2020). Laparoscopy-assisted versus balloon enteroscopy-assisted ERCP after Roux-en-Y gastric bypass. Endoscopy. ISSN 0013-726X. 52(8), p. 654–661. doi: 10.1055/a-1139-9313. Full text in Research Archive
• Gharagozlian, Sedegheh; Mala, Tom; Brekke, Hilde Kristin; Kolbjørnsen, Lisa Cornelia; Ullerud, Åslaug Asgeirsdatter & Johnson, Egil (2020). Nutritional status, sarcopenia, gastrointestinal symptoms and quality of life after gastrectomy for cancer - A cross-sectional pilot study. Clinical Nutrition ESPEN. ISSN 2405-4577. 37, p. 195–201. doi: 10.1016/j.clnesp.2020.03.001. Full text in Research Archive Show summary

  <i>Background and aims</i> - Gastrointestinal (GI) symptoms, malabsorption, reduced food intake and weight loss are common sequela of gastrectomy. This can result in malnutrition with a subsequent prolonged recovery, reduced physical functioning and deteriorated quality of life (QoL). Few studies have investigated the relationship between GI-symptoms, QoL and malnutrition in long-term survivors of gastric cancer. Therefore, we assess nutritional status, GI-symptoms and QoL 2–5 years after gastrectomy for malignancy.<br><br> <i>Methods</i> - A cross-sectional, pilot study was carried out in patients who underwent total or subtotal gastrectomy at Oslo University Hospital between 2012 and 2016, who had not experienced disease recurrence. Subjects above 85 years were excluded. The nutritional status of the patients fell into three groups by a score of subjective global assessment (SGA)-A, B, and C. Muscle mass was measured by body composition by bioelectrical impedance analysis and muscle strength was measured by handgrip strength (HGS). Dietary intake was assessed by repeated 24-h dietary recalls. GI-symptoms and QoL were assessed using GI-Symptom Rating Scale (GSRS) and the SF-36 questionnaire.<br><br> <i>Results</i> - 21 patients were included. Mean (SD) weight loss was 12.8% (11.6) from preoperative status to follow up. Percentage weight loss was larger after total gastrectomy compared with subtotal gastrectomy (17.9% (12.3) vs. 6.6% (7.1) (p = 0.03)). A low mean intake of energy and protein was reported compared to dietary recommendations for the general Nordic population and intake in a national dietary survey. All of the patients were classified as pre-sarcopenic, and 5% as sarcopenic. Persistent weight loss >10% was observed in 45% of the subjects and these were in risk of malnutrition. Subjects with malnutrition had higher GSRS score for the abdominal pain syndrome (p = 0.042) and lower SF-36 scores for bodily pain (p = 0.01) and vitality (p = 0.02) compared with those without malnutrition.<br><br> <i>Conclusions</i> - A high prevalence of weight loss, and pre-sarcopenia was observed. Malnutrition as assessed by SGA was associated with more GI-Symptoms and reduced QoL scores. Further studies with larger number of participants are needed to verify our findings.

• Poelemeijer, Youri Q M; Liem, Ronald S L; Våge, Villy; Mala, Tom; Sundbom, Magnus & Ottosson, Johan [Show all 7 contributors for this article] (2020). Gastric Bypass Versus Sleeve Gastrectomy: Patient Selection and Short-term Outcome of 47,101 Primary Operations From the Swedish, Norwegian, and Dutch National Quality Registries. Annals of Surgery. ISSN 0003-4932. 272(2), p. 326–333. doi: 10.1097/SLA.0000000000003279. Full text in Research Archive
• Hewitt, Stephen I; Kristinsson, Jon Adalsteinn; Aasheim, Erlend T.; Høgestøl, Ingvild Kristine; Aaseth, Eirik & Jahnsen, Jørgen [Show all 8 contributors for this article] (2020). Relationships Between Vitamin D Status and PTH over 5 Years After Roux-en-Y Gastric Bypass: a Longitudinal Cohort Study. Obesity Surgery. ISSN 0960-8923. 30(9), p. 3426–3434. doi: 10.1007/s11695-020-04582-5. Full text in Research Archive Show summary

  Abstract Purpose Secondary hyperparathyroidism (SHPT) after obesity surgery may affect bone health. Optimal vitamin D levels have not been established to prevent SHPT postoperatively. We investigated whether SHPT differed across threshold levels of serum 25-hydroxyvitamin D (S-25(OH)D) from 6 months up to 5 years after Roux-en-Y gastric bypass (RYGB). Materials and Methods We included 554 patients at follow-up 5 years postoperatively. Blood samples were analysed for S-25(OH)D, ionized calcium (iCa) and parathyroid hormone (PTH) during follow-up. Results PTH and prevalence of SHPT increased from 6 months to 5 years postoperatively, while S-25(OH)D and iCa decreased (all P < 0.001). PTH and SHPT development are related with S-25(OH)D, and PTH differed between all subgroups of S-25(OH)D. SHPT occurred less frequently across all subgroups of S-25(OH)D ≥ 50 nmol/l during follow-up: odds ratio (OR) 0.44 (95% CI 0.36–0.54) in patients with S-25(OH)D ≥ 50 nmol/l, OR 0.38 (0.30–0.49) with S-25(OH)D ≥ 75 nmol/l and OR 0.19 (0.12–0.31) with S-25(OH) D ≥ 100 nmol/l, all compared with S-25(OH)D < 50 nmol/l. At 5 years, 208/554 patients (38%) had SHPT; SHPT was found in 94/188 patients (50%) with S-25(OH)D < 50 nmol/l, in 69/222 (31%) with S-25(OH)D 50–74 nmol/l, in 40/117 (34%) with S-25(OH)D 75–99 nmol/l and in 5/27 (19%) with S-25(OH)D ≥ 100 nmol/l. An interaction existed between S-25(OH)D and iCa. Bone alkaline phosphatase remained increased with SHPT. Conclusions A significant relationship existed between S-25(OH)D and development of PTH and SHPT. The prevalence of SHPT was lower with threshold levels 25(OH)D ≥ 50 nmol/l and ≥ 75 nmol/l over the 5 years, and lowest with S-25(OH)D ≥ 100 nmol/l. Keywords Bariatric surgery . Morbid obesity . Vitamin D . Calcium . Parathyroid hormone . Bone turnover

• Svanevik, Marius; Risstad, Hilde; Hofsø, Dag; Høgestøl, Ingvild Kristine; Kristinsson, Jon Adalsteinn & Sandbu, Rune [Show all 10 contributors for this article] (2019). Bone Turnover Markers After Standard and Distal Roux-en-Y Gastric Bypass: Results from a Randomized Controlled Trial. Obesity Surgery. ISSN 0960-8923. 29(9), p. 2886–2895. doi: 10.1007/s11695-019-03909-1. Full text in Research Archive Show summary

  Background: Roux-en-Y gastric bypass is associated with increased risk of bone fractures. Malabsorptive procedures may be associated with secondary hyperparathyroidism and detrimental effects on bone health. We aimed to compare the effects of standard and distal gastric bypass on bone turnover markers 2 years after surgery. Methods: Patients with body mass index (BMI) 50–60kg/m2 (n=113) were randomized to standard or distal gastric bypass,105 patients (95%) completed 2-year follow-up. Serum C-terminal telopeptide of type I collagen (CTX-1), procollagen type I Npropeptide (PINP), and bone-derived alkaline phosphatase (BALP) was measured at baseline and up to 2 years after surgery. ANCOVA and linear mixed models were used to compare groups. Results: The levels of bone turnover markers increased significantly in both groups, with no statistically significant difference betweengroups.Two years after standard and distal gastric bypass mean (SD) CTX-1 were 0.81 (0.32) and 0.83 (0.31) μg/L (p= 0.38), mean PINP was 77.6 (23.2) and 77.7 (29.3) μg/L (p=0.42), and BALP 47.9 (21.9) vs. 50.7 (19.6) μg/L (p=0.38), respectively. Multiple linear regression analyses showed that PINP and BALP correlated positively (p=0.01 and p <0.001) with PTH, but only BALP was significantly higher in patients with secondary hyperparathyroidism (p=0.001). Type of surgery, vitamin D serum concentrations, and 2-year BMI were all independently associated with PTH levels. Conclusion: A comparable increase in bone turnover markers 2 years after standard and distal gastric bypass was observed. There was a higher prevalence of secondary hyperparathyroidism after distal gastric bypass, but this did not impact bone turnover markers.

• Salte, Odd Bjørn; Søvik, Torgeir Thorson; Risstad, Hilde; Skattum, Jorunn Pettersen; Høgestøl, Ingvild Kristine & Eribe, Inger [Show all 8 contributors for this article] (2019). Fedmekirurgi ved Oslo universitetssykehus 2004-14. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 139(10), p. 921–926. doi: 10.4045/tidsskr.18.0495. Full text in Research Archive
• Chahal-Kummen, Monica; Høgestøl, Ingvild Kristine; Eribe, Inger; Klungsøyr, Ole; Kristinsson, Jon Adalsteinn & Mala, Tom (2019). Abdominal pain and symptoms before and after Roux-en-Y gastric bypass. BJS Open. 3(3), p. 317–326. doi: 10.1002/bjs5.50148. Full text in Research Archive Show summary

  Background Despite increased emphasis on patient‐reported outcomes, few studies have focused on abdominal pain symptoms before and after Roux‐en‐Y gastric bypass (RYGB). The aim of this study was to quantify chronic abdominal pain (CAP) in relation to RYGB. Methods Patients with morbid obesity planned for RYGB were invited to participate at a tertiary referral centre from February 2014 to June 2015. Participants completed a series of seven questionnaires before and 2 years after RYGB. CAP was defined as patient‐reported presence of long‐term or recurrent abdominal pain lasting for more than 3 months. Results A total of 236 patients were included, of whom 209 (88·6 per cent) attended follow‐up. CAP was reported by 28 patients (11·9 per cent) at baseline and 60 (28·7 per cent) at follow‐up (P  < 0·001). Gastrointestinal Symptom Rating Scale (GSRS) scores (except reflux scores) and symptoms of anxiety increased from baseline to follow‐up. Most quality of life (QoL) scores (except role emotional, mental health and mental component scores) also increased. At follow‐up, patients with CAP had higher GSRS scores than those without CAP, with large effect sizes for abdominal pain and indigestion syndrome scores. Patients with CAP had more symptoms of anxiety, higher levels of catastrophizing and lower QoL scores. Baseline CAP seemed to predict CAP at follow‐up. Conclusion The prevalence of CAP is higher 2 years after RYGB compared with baseline values.

• Salte, Odd Bjørn; Søvik, Torgeir Thorson; Risstad, Hilde; Skattum, Jorunn Pettersen; Høgestøl, Ingvild Kristine & Eribe, Inger [Show all 8 contributors for this article] (2019). Bariatric surgery at Oslo University Hospital 2004-14. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 139(10), p. 921–926. doi: 10.4045/tidsskr.18.0495. Full text in Research Archive
• Høgestøl, Ingvild Kristine; Mala, Tom; Kristinsson, Jon Adalsteinn; Hauge, Ellen Margrethe; Brunborg, Cathrine & Gulseth, Hanne Løvdal [Show all 7 contributors for this article] (2019). Changes in Bone Marrow Adipose Tissue One Year After Roux‐en‐Y Gastric Bypass: A Prospective Cohort Study. Journal of Bone and Mineral Research. ISSN 0884-0431. 34(10), p. 1815–1823. doi: 10.1002/jbmr.3814. Full text in Research Archive Show summary

  Bone marrow adipose tissue (BMAT) has been postulated to mediate skeletal fragility in type 2 diabetes (T2D) and obesity. Roux‐en‐Y gastric bypass (RYGB) induces a substantial weight loss and resolution of comorbidities. However, the procedure induces increased bone turnover and fracture rates. No previous study has evaluated biopsy‐measured BMAT fraction preoperatively and after RYGB. In this study, we aimed to investigate BMAT fraction of the hip in participants with and without T2D preoperatively and 1 year after RYGB and explore factors associated with BMAT change. Patients with morbid obesity scheduled for RYGB were examined preoperatively and 1 year after RYGB. Forty‐four participants were included and preoperative examinations were possible in 35. Of these, 33 (94%) met for follow‐up, 2 were excluded, and BMAT estimation was not possible in 1. Eighteen (60%) of the participants were females and 11 (37%) had T2D. Preoperative BMAT fraction was positively associated with glycosylated hemoglobin and negatively associated with areal bone mineral density (aBMD). After RYGB, BMAT fraction decreased from 40.4 ± 1.7% to 35.6 ± 12.8%, p  = 0.042, or with mean percent change of 10.7% of preoperative BMAT fraction. Change in BMAT fraction was positively associated with change in body mass index (BMI) and total body fat. In females, we observed a mean percent reduction of 22.4 ± 19.6%, whereas in males BMAT increased with a mean percent of 6.8 ± 37.5%, p  = 0.009. For males, changes in estradiol were associated with BMAT change; this was not observed for females. In participants with and without T2D, the mean percent BMAT reduction was 5.8 ± 36.9% and 13.5 ± 28.0%, respectively, p  = 0.52. We conclude that a high BMAT seems to be associated with lower aBMD and poorer glycemic control in obese subjects. After RYGB, we observed a significant decrease in BMAT. The reduction in BMAT did not differ between participants with and without T2D, but appeared sex specific.

• Høgestøl, Ingvild Kristine; Hewitt, Stephen I; Chahal-Kummen, Monica; Brunborg, Cathrine; Gulseth, Hanne Løvdal & Kristinsson, Jon Adalsteinn [Show all 8 contributors for this article] (2019). Bone metabolism, bone mineral density and low-energy fractures 10 years after Roux-en-Y gastric bypass. Bone. ISSN 8756-3282. 127, p. 436–445. doi: 10.1016/j.bone.2019.07.014. Full text in Research Archive Show summary

  Background Roux-en-Y gastric bypass (RYGB) is a common surgical procedure for treatment of morbid obesity. RYGB induces considerable and sustained weight loss, and remission of obesity related-comorbidities. While studies have suggested negative effects of RYGB on bone health, long-term data are lacking. We aimed to evaluate the prevalence of aBMD below the expected range for age, osteopenia, osteoporosis and low-energy fractures in a defined patient cohort 10 years after RYGB. Secondly, we wanted to identify factors associated with increased risk of aBMD z-score or t-score of −1.1 or lower 10 years after RYGB. Methods Patients undergoing RYGB surgery from June 2004 to December 2006 at the Department of Morbid Obesity and Bariatric Surgery, Oslo University Hospital, a tertiary referral centre for treatment of morbid obesity, were invited to a 10 year follow-up. Follow-up visits included morning fasting blood samples, clinical examination, anthropometric measures and dual energy X-ray absorptiometry (DXA). Results Out of 194 patients eligible for the study, 124 attended the 10 year follow-up and 122 (63%) were examined with DXA. Mean (SD) age was 50.3 (9.0) years, 118 (97%) were of Caucasian ethnicity, 94 were females (77%), of whom 41 (44%) were postmenopausal. Secondary hyperparathyroidism (SHPT) was noted in 37 participants (31%) and vitamin D deficiency (value below 50 nmol/L) and insufficiency (value below 75 nmol/L) in 40 (33%) and 91 (75%), respectively. Among the 63 participants who were premenopausal females or males 49 years or younger the prevalence of areal bone mineral density (aBMD) in the lower range of normal (z-score −1.1- to −1.9) was 30% (n = 19) and aBMD below the expected range for age (z-score ≤ −2.0) was noted in 8% (n = 5). Among the 59 participants who were postmenopausal females or males 50 years or older, the prevalence of osteopenia (t-score −1.1 to −2.4) was 51% (n = 30) and osteoporosis (t-score ≤ −2.5) was 27% (n = 16). The bone resorption markers CTX-1 and PINP were higher in participants with aBMD z-score or t-score of −1.1 or lower compared to participants with aBMD z-score or t-score of −1.0 or higher. Preoperative hypothyroidism, or higher age, postmenopausal status, BMI < 35 kg/m2, SHPT or higher PINP levels at 10 year follow-up were independently associated with aBMD z-score or t-score of −1.1 or lower 10 years after RYGB. Eighteen participants (15%) reported a clinical low-energy fracture after RYGB. In addition, vertebral fracture assessment by DXA revealed that 10 participants (8%) had experienced at least one moderate to severe morphometric vertebral fracture. Conclusion Ten years after RYGB 27% of postmenopausal females and males 50 years or older were osteoporotic, and 8% of premenopausal females and males 49 years or younger exhibited aBMD below the expected range for age. The prevalence of fragility fractures was high. SHPT, higher age, postmenopausal status or higher PINP levels at 10 years and preoperative hypothyroidism were all independent risk factors for aBMD z-score or t-score of −1.1 or lower 10 years after RYGB.

• Høgestøl, Ingvild Kristine; Aasbrenn, Martin; Chahal-Kummen, Monica; Brunborg, Cathrine; Eribe, Inger & Kristinsson, Jon Adalsteinn [Show all 8 contributors for this article] (2019). Irritable bowel syndrome-like symptoms and health related quality of life two years after Roux-en-Y gastric bypass - a prospective cohort study. BMC Gastroenterology. 19:204(1), p. 1–11. doi: 10.1186/s12876-019-1103-0. Full text in Research Archive Show summary

  BACKGROUND: Irritable bowel syndrome (IBS) is prevalent in patients with morbid obesity. After Roux-en-Y gastric bypass (RYGB) chronic abdominal pain is common, however the etiology is largely unknown. We aimed to study the change in the prevalence of IBS-like symptoms 2 years after RYGB and possible preoperative predictors of such symptoms. Secondly, to evaluate changes in symptoms of constipation and diarrhea, and Health related quality of life (HRQoL). METHODS: Patients with morbid obesity were included at two obesity centers in South-Eastern Norway. IBS was diagnosed according to the Rome III criteria. Predictors were evaluated in a multivariable logistic regression analysis. RESULTS: Of 307 participants operated with RYGB, 233 (76%) completed the study questionnaires. Preoperatively 27/233 participants (12%) had IBS, 2 years after RYGB 61/233 (26%) had IBS-like symptoms (p < 0.001). Eleven participants with IBS preoperatively (41%) did not report such symptoms after RYGB. New onset IBS-like symptoms was identified in 45/206 (22%) after RYGB. Fibromyalgia, low LDL levels, high vitamin B1 levels and IBS before RYGB were independent preoperative predictors of IBS-like symptoms at the follow-up visit. Symptom scores for constipation preoperatively and 2 year after RYGB were 1.5 (0.9) and 1.8 (1.2), and for diarrhea 1.4 (0.9) and 1.8 (1.1), respectively (p < 0.001). We observed a significant improvement in the physical component score for all participants. However, participants with new onset IBS-like symptoms had a significant worsening of the mental component score. CONCLUSIONS: The prevalence of IBS-like symptoms doubled 2 years after RYGB, and these symptoms were associated with reduced HRQoL. Preoperative IBS and fibromyalgia were strong predictors of postoperative IBS-like symptoms.

• Høgestøl, Ingvild Kristine; Mala, Tom; Kristinsson, Jon Adalsteinn; Brunborg, Cathrine; Gulseth, Hanne Løvdal & Eriksen, Erik Fink (2019). Changes in bone quality after Roux-en-Y gastric bypass: A prospective cohort study in subjects with and without type 2 diabetes. Bone. ISSN 8756-3282. 130. doi: 10.1016/j.bone.2019.115069. Full text in Research Archive Show summary

  Background Obesity and type 2 diabetes (T2D) are associated with an increased risk of skeletal fractures despite a normal areal bone mineral density (aBMD) and low bone turnover, possibly due to reduced bone material strength. Roux-en-Y gastric bypass (RYGB) enables a substantial and persistent weight loss and resolution of obesity related comorbidities such as T2D. However, the procedure induces a decrease in aBMD and increased bone turnover and fracture rate. To our knowledge, changes in bone material strength after RYGB have not been explored. This study aimed to evaluate changes in factors influencing bone quality; bone material strength, aBMD and bone turnover markers, in a population with morbid obesity undergoing RYGB and whether these changes differed in participants with and without T2D. We also sought to assess factors associated with bone material strength and bone mineral density in obese subjects before and after RYGB. Methods We examined 34 participants before and one year after RYGB, of whom 13 had T2D. Bone material strength index (BMSi) was evaluated by impact microindentation, aBMD and body composition by Dual energy X-ray absorptiometry, levels of bone turnover markers and calciotropic hormones were estimated from fasting serum samples. Participants with and without T2D were comparable before surgery, with the exception of glycosylated hemoglobin (HbA1c). Results Preoperatively, BMSi was inversely associated with BMI, βunadjusted -1.1 (-1.9 to -0.28), R2 = 0.19, p = 0.010, and this association remained significant after adjusting for age and gender. After RYGB the participants had lost a mean ± SD of 33.9 ± 10.9 kg, 48.7 ± 14.2 % of total body fat, increased physical activity, unchanged vitamin D levels, and all but one of the 13 participants with T2D were in diabetes remission. BMSi increased from 78.1 ± 8.5 preoperatively to 82.0 ± 6.4 one year after RYGB, corresponding to an increase of 4.0 ± 9.8 in absolute units or 6.3 ± 14.0 %, p = 0.037. The increase was comparable in participants with and without T2D. In subjects with T2D, a larger decrease in HbA1c was associated with a larger increase in BMSi βunadjusted -9.2 (-16.5 to -1.9), R2 = 0.47, p = 0.019. Bone turnover markers (CTX-1 and PINP) increased by 195.1 ± 133.5 % and 109.5 ± 70.6 %, respectively. aBMD decreased by 3.9 ± 5.5 % in the lumbar spine, 8.2 ± 4.6 % in the femoral neck, 11.6 ± 4.9 % in total hip and 9.4 ± 3.8 % in total body. Conclusion Our findings indicate that bone material strength improves despite an increase in bone turnover and a decrease in aBMD one year after RYGB. Trends were statistically comparable in participants with and without T2D. However, improved glucose control was associated with improved bone material strength in participants with T2D.

• Poelemeijer, Youri Q M; Liem, Ronald S L; Våge, Villy; Mala, Tom; Sundbom, Magnus & Ottosson, Johan [Show all 7 contributors for this article] (2018). Perioperative Outcomes of Primary Bariatric Surgery in North-Western Europe: a Pooled Multinational Registry Analysis. Obesity Surgery. ISSN 0960-8923. 28(12), p. 3916–3922. doi: 10.1007/s11695-018-3408-4. Full text in Research Archive
• Mala, Tom & Høgestøl, Ingvild Kristine (2018). Abdominal Pain After Roux-En-Y Gastric Bypass for Morbid Obesity. Scandinavian Journal of Surgery. ISSN 1457-4969. 107(4), p. 277–284. doi: 10.1177/1457496918772360. Full text in Research Archive
• Werling, Malin; Fandriks, Lars; Olbers, Torsten; Mala, Tom; Kristinsson, Jon Adalsteinn & Stenlof, Kaj [Show all 9 contributors for this article] (2018). Biliopancreatic Diversion is associated with greater increases in energy expenditure than Roux-en-Y Gastric Bypass. PLOS ONE. 13(4), p. 1–12. doi: 10.1371/journal.pone.0194538. Full text in Research Archive
• Hewitt, Stephen I; AASHEIM, ERLEND T.; Søvik, Torgeir Thorson; Jahnsen, Jørgen; Kristinsson, Jon Adalsteinn & Eriksen, Erik Fink [Show all 7 contributors for this article] (2018). Relationships of serum 25-hydroxyvitamin D, ionized calcium and parathyroid hormone after obesity surgery. Clinical Endocrinology. ISSN 0300-0664. 88(3), p. 372–379. doi: 10.1111/cen.13531. Full text in Research Archive
• Haug, Helene Marie; Johnson, Egil; Mala, Tom; Førland, Dag T.; Søvik, Torgeir Thorson & Johannessen, Hans Olaf (2018). Incarcerated paraesophagel hernia complicated by pancreatic damage and unusual comorbidity: Two retrospective case series. International Journal of Surgery Case Reports (IJSCR). 54, p. 75–78. doi: 10.1016/j.ijscr.2018.11.064. Full text in Research Archive Show summary

  Introduction: About 1% of paraesophageal hernias (PEH) require emergency surgery due to obstruction or gangrene. We present two complicated cases of incarcerated PEH. Presentation of cases: A patient aged 18 with trisomy 21 was admitted after four days of vomiting and epigastric pain. CT scan revealed a large PEH. The stomach was massively dilated with compression of adjacent viscera and the celiac trunk. The stomach was repositioned laparoscopically and deflated by endoscopy in an attemptto avoid resection. During second look laparoscopy a gastrectomy was necessary. The patient was reoperated for intestinal obstruction, and treated for dehiscence of the esophagojejunostomy and a pancreatic fistula. A patient aged 65 with hereditary spastic paresis had two days history of emesis and epigastric pain. Upon arrival he was hemodynamically unstable and a CT scan revealed perforation of the herniated stomach. A subtotal gastrectomy without reconstruction was performed with vacuum closure of the abdomen. Later a gastrectomy was completed with a Roux-en-Y reconstruction. Except from reoperation for wound dehiscence after 14 days, the recovery was uneventful. Discussion: Trisomy 21 and hereditary spastic paresis may increase the risk of developing PEH. Challenges in regard to symptom evaluation may delay diagnosis. The pressure ofthe dilated stomach can give rise to ischemic and mechanical damage from compression of major blood vessels and organs. Urgent diagnosis and gastric deflation is required. Conclusions: In patients with known PEH or with comorbidity that may increase the risk of PEH, this diagnosis should be considered early on.

• Engebretsen, Kristin V Thunheim; Høgestøl, Ingvild Kristine; Hewitt, Stephen I; Risstad, Hilde; Moum, Bjørn & Kristinsson, Jon Adalsteinn [Show all 7 contributors for this article] (2018). Anemia following Roux-en-Y gastric bypass for morbid obesity; a 5-year follow-up study. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 53(8), p. 917–922. doi: 10.1080/00365521.2018.1489892. Full text in Research Archive
• Høgestøl, Ingvild Kristine; Stubhaug, Audun; Kristinsson, Jon Adalsteinn & Mala, Tom (2018). Diagnosis and treatment of chronic abdominal pain 5 years after Roux-en-Y gastric bypass. Surgery for Obesity and Related Diseases. ISSN 1550-7289. 14(10), p. 1528–1535. doi: 10.1016/j.soard.2018.06.004. Full text in Research Archive
• Mala, Tom; Johannessen, Hans Olaf; Førland, Dag T.; Jacobsen, Thor & Johnson, Egil (2018). Laparoskopisk reseksjon av ventrikkelcancer ved Oslo universitetssykehus, Ullevål 2015-18. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 138(18), p. 1–10. doi: 10.4045/tidsskr.18.0404. Full text in Research Archive

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• Haug, Helene Marie; Hagen, Rolf Eikeland; Kristinsson, Jon Adalsteinn; Svanevik, Marius; Sandbu, Rune & Medhus, Asle Wilhelm [Show all 10 contributors for this article] (2026). A two-center randomized clinical superiority trial of single-anastomosis sleeve ileal bypass versus sleeve gastrectomy for severe obesity: SASSY study protocol. doi: 10.1177/14574969261470903. Full text in Research Archive Show summary

  Background: Single-anastomosis sleeve ileal bypass is a novel metabolic bariatric surgery intended to enhance metabolic outcomes and reduce the risk of postoperative complications. Although preliminary outcome data for single-anastomosis sleeve ileal bypass are promising, evidence from adequately powered, randomized head-to-head comparisons is scarce. This trial compares the efficacy and safety of single-anastomosis sleeve ileal bypass versus sleeve gastrectomy in patients with class II obesity (body mass index = 35.0–39.9 kg/m²) with at least one obesity‑related comorbidity or class III obesity (body mass index ⩾40.0 kg/m²). Methods: This two-center randomized clinical superiority trial enrolls patients eligible for metabolic bariatric surgery at two specialized Norwegian centers. Included patients are randomly assigned (1:1) to either single-anastomosis sleeve ileal bypass or sleeve gastrectomy with standardized perioperative treatment and care. The primary endpoint is the between-group difference in change in body mass index from baseline to 2 years after single-anastomosis sleeve ileal bypass versus sleeve gastrectomy. Secondary endpoints include additional weight loss outcomes, the prevalence of gastroesophageal reflux disease, surgical and postoperative complications, obesity-related comorbidities, nutritional status, bone mineral density, gastrointestinal symptoms, quality of life, and rates of revisional and conversion surgery. All endpoints will be evaluated at 2 and 5 years after surgery. Statistical analyses utilize linear mixed models and analysis of covariance within an intention-to-treat framework. Discussion: This trial will provide high-level evidence with robust and comparative outcome data on single-anastomosis sleeve ileal bypass and sleeve gastrectomy, aiming to clarify the clinical utility of single-anastomosis sleeve ileal bypass and inform surgical practice. Findings will address gaps in medium- and long-term evidence regarding weight loss, safety, comorbidity resolution, and quality of life following single-anastomosis sleeve ileal bypass.

• Hewitt, Stephen I; Hofsø, Dag; Qvigstad, Elisabeth; Berg, Tore Julsrud; Chahal-Kummen, Monica & Kristinsson, Jon Adalsteinn [Show all 7 contributors for this article] (2025). Hypoglykemi etter fedmekirurgi. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 145(6). doi: 10.4045/tidsskr.24.0396. Full text in Research Archive Show summary

  Omfanget av fedmekirurgi har økt vår erkjennelse av hypoglykemi som en komplikasjon, og forekomsten synes høyere enn tidligere anslått. Pasientene har oftest milde til moderate symptomer, og de fleste har god effekt av kostholdstilpasninger. Et fåtall får kramper, synkoperer eller klarer ikke ta vare på seg selv. Hypoglykemien knyttes til både vektavhengige og vektuavhengige mekanismer, med både bedret insulinsensitivitet og økt frigjøring av inkretinhormoner, som glukagonlignende peptid 1. Hovedprinsippet i behandlingen er å begrense svingninger i nivåene av blodglukose og insulin etter måltider. Enkelte medikamenter kan avhjelpe tilstanden, men brukes lite. I denne kliniske oversikten oppsummeres noen viktige hensyn for leger som møter disse pasientene.

• Kazaryan, Airazat M.; Hagve, Martin Iversen; Mala, Tom; Augestad, Knut Magne; Nordby, Tom & Edwin, Bjørn von Gohren [Show all 7 contributors for this article] (2024). Forskning og vitenskaplig skriving 3. Formidling av forskningen i moderne tid – bedre tilgang, nye medier og fagfellerollen. Kirurgen. ISSN 1504-8888. 4, p. 238–240. Full text in Research Archive Show summary

  Denne artikkelserien som består av tre kronikker belyser faktorer som kan motivere til medisinsk forskning. Ulike typer av medisinske publikasjoner framstilles. I tillegg beskrives forutsetninger som kan bidra til vellykket publisering. Det gis en oversikt over trender i forskningspublisering, samt forklaring av betegnelsene oppdagelse og innovasjon. Her drøftes også forskningen og den vitenskapelige skrivningens rolle og betydning for framgangen innen medisin og helsevesen, og videre belyses sammenhengen mellom medisinsk praksis og forskning. Ikke minst poengteres behov om støtte fra veileder og ledelse i forsknings- og publiseringsprosessen. Kronikk 3 omhandler tema «Formidling av forskningen»

• Kazaryan, Airazat M.; Mala, Tom; Hagve, Martin Iversen; Augestad, Knut Magne; Nordby, Tom & Ghanima, Waleed [Show all 7 contributors for this article] (2024). Forskning og vitenskaplig skriving 2. Fra ide til ferdig artikkel. Kirurgen. ISSN 1504-8888. 4, p. 234–237. Full text in Research Archive Show summary

  Denne artikkelserien, som består av tre kronikker, belyser faktorer som kan motivere til medisinsk forskning. Ulike typer av medisinske publikasjoner framstilles. I tillegg beskrives forutsetninger som kan bidra til vellykket publisering. Det gis en oversikt over trender i forskningspublisering samt forklaring av betegnelsene oppdagelse og innovasjon. Her drøftes også forskningen og den vitenskapelige skrivningens rolle og betydning for framgangen innen medisin og helsevesen, og videre belyses sammenhengen mellom medisinsk praksis og forskning. Ikke minst poengteres behov om støtte fra veileder og ledelse i forsknings- og publiseringsprosessen. Kronikk 2 inkluderer tema «Fra idé til ferdig artikkel»

• Kazarian, Airazat; Mala, Tom; Hagve, Martin Iversen; Augestad, Knut Magne; Nordby, Tom & Edwin, Bjørn von Gohren [Show all 7 contributors for this article] (2024). Forskning og vitenskaplig skriving 1. Hvordan komme igang ? Kirurgen. ISSN 1504-8888. Full text in Research Archive
• Hedberg, Jakob; Sundbom, Magnus; Edholm, David; Aahlin, Eirik Kjus; Szabo, Eva & Lindberg, Fredrik [Show all 19 contributors for this article] (2024). Randomized controlled trial of nasogastric tube use after esophagectomy: Study protocol for the kinetic trial. Diseases of the esophagus. ISSN 1120-8694. 37(6). doi: 10.1093/dote/doae010. Full text in Research Archive Show summary

  Summary Esophagectomy is a complex and complication laden procedure. Despite centralization, variations in perioparative strategies reflect a paucity of evidence regarding optimal routines. The use of nasogastric (NG) tubes post esophagectomy is typically associated with significant discomfort for the patients. We hypothesize that immediate postoperative removal of the NG tube is non-inferior to current routines. All Nordic Upper Gastrointestinal Cancer centers were invited to participate in this open-label pragmatic randomized controlled trial (RCT). Inclusion criteria include resection for locally advanced esophageal cancer with gastric tube reconstruction. A pretrial survey was undertaken and was the foundation for a consensus process resulting in the Kinetic trial, an RCT allocating patients to either no use of a NG tube (intervention) or 5 days of postoperative NG tube use (control) with anastomotic leakage as primary endpoint. Secondary endpoints include pulmonary complications, overall complications, length of stay, health related quality of life. A sample size of 450 patients is planned (Kinetic trial: https://www.isrctn.com/ISRCTN39935085). Thirteen Nordic centers with a combined catchment area of 17 million inhabitants have entered the trial and ethical approval was granted in Sweden, Norway, Finland, and Denmark. All centers routinely use NG tube and all but one center use total or hybrid minimally invasive-surgical approach. Inclusion began in January 2022 and the first annual safety board assessment has deemed the trial safe and recommended continuation. We have launched the first adequately powered multi-center pragmatic controlled randomized clinical trial regarding NG tube use after esophagectomy with gastric conduit reconstruction.

• Mala, Tom; Abelseth, Bente Kristin; Al-Haidari, Ghazwan; Dørum, Liv Marit Rønning; Hatlevoll, Ingunn & Rekstad, Lars Cato [Show all 9 contributors for this article] (2024). Kreft i spiserøret – betydelig bedre overlevelse. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 144(15), p. 1–4. doi: 10.4045/tidsskr.24.0547. Full text in Research Archive
• Mala, Tom (2023). Abdominal pain - a foe in the oechestra of improving symptoms after Roux-en-y gastric bypass surgery. doi: 10.1111/cob.12582. Full text in Research Archive
• Mala, Tom; Yakub, Sheraz & Saeed, Usman (2023). Redusert kreftrisiko etter fedmekirurgi. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 143(13). doi: 10.4045/tidsskr.23.0501. Full text in Research Archive
• Henmo, Ola; Helland, Åslaug; Mala, Tom; Verbeke, Caroline Sophie & Bjerkvig, Rolf (2023). Dette superteamet skal løse våre største kreftutfordringer. [Journal]. Forskning.no. Full text in Research Archive
• Mala, Tom; Søvik, Torgeir Thorson & Kristinsson, Jon Adalsteinn (2022). Gastroskopi euer langsgående ventrikkelreseksjon for sykelig overvekt. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 142. doi: 10.4045/tidsskr.22.0056. Full text in Research Archive
• Kazaryan, Airazat M.; Eftang, Lars Lohne; Ødegaard, Pål; Hagve, Martin Iversen; Skjold-Ødegaard, Benedicte & Olsen, Ole Christian [Show all 21 contributors for this article] (2022). Appendisittbehandlingen bør standardiseres. 142(11). doi: 10.4045/tidsskr.22.0232. Full text in Research Archive
• Mala, Tom; Chahal-Kummen, Monica & Kristinsson, Jon (2021). Letter to the Editor. Obesity Surgery. ISSN 0960-8923. 31(12), p. 5459–5459. doi: 10.1007/s11695-021-05523-6. Full text in Research Archive
• Butler, John; Finley, Christian; Norell, Charles H; Harrison, Samantha; Bryant, Heather & Achiam, Michael P [Show all 32 contributors for this article] (2020). New approaches to cancer care in a COVID-19 world. The Lancet Oncology. ISSN 1470-2045. 21(7), p. e339–e340. doi: 10.1016/S1470-2045(20)30340-5. Full text in Research Archive
• Saeed, Usman; Mala, Tom & Young, Victoria Solveig (2020). Covid‐19 may present with acute abdominal pain. British Journal of Surgery. ISSN 0007-1323. doi: 10.1002/bjs.11674. Full text in Research Archive
• Svanevik, Marius; Salte, Odd Bjørn; Risstad, Hilde; Hjelmesæth, Jøran; Høgestøl, Ingvild Kristine & Hertel, Jens Kristoffer [Show all 10 contributors for this article] (2019). BMI loss and resolution of diabetes five years after standard and distal roux-en-y gastric bypass. Surgery for Obesity and Related Diseases. ISSN 1550-7289. 15, p. S115–S115. doi: 10.1016/j.soard.2019.08.234. Full text in Research Archive
• Salte, O.B.; Svanevik, Marius; Risstad, H.; Hjelmesæth, Jøran; Høgestøl, Ingvild Kristine & Hertel, Jens Kristoffer [Show all 10 contributors for this article] (2019). Body mass index 5 years after standard and distal Roux-en-Y gastric bypass-preliminary results from a randomized controlled trial. Obesity Surgery. ISSN 0960-8923. 29. Full text in Research Archive
• Reas, Deborah; Johansen, Judita; Alshus, Ingvild; Mala, Tom & Kvalem, Ingela Lundin (2018). Stability and impact of pre- and post-operative binge-eating behavior on weight loss outcome at 1- and 3-years following bariatric surgery. Full text in Research Archive
• Mala, Tom & Kristinsson, Jon Adalsteinn (2017). Gastrointestinal symptoms after bariatric surgery - more focus needed. Surgery for Obesity and Related Diseases. ISSN 1550-7289. 13(7), p. 1251–1251. doi: 10.1016/j.soard.2017.03.009. Full text in Research Archive
• Giske, Liv; Stoinska-Schneider, Anna; Hjelmesæth, Jøran; Mala, Tom; Arentz-Hansen, Eva Helene & Elvsaas, Ida-Kristin Ørjasæter [Show all 10 contributors for this article] (2018). Fedmekirurgi ved diabetes type 2 og kroppsmasseindeks under 35 - fullstendig metodevurdering. Folkehelseinstituttet. ISSN 9788280829108. Full text in Research Archive Show summary

  Hovedbudskap Vi har utført en metodevurdering som omhandler effekt, sikkerhet og en helseøkonomisk evaluering av fedmekirurgi for pasienter med diabetes type 2 og KMI under 35 sammenliknet med standard behandling. Vi inkluderte fire randomiserte- og seks ikke-randomiserte studier samt en stor registerstudie uten kontrollgruppe. Etter en oppfølgingstid på to år fant vi at: • I gjennomsnitt oppnådde 44 % av pasientene i kirurgigruppen remisjon av diabetes type 2 sammenliknet med 3 % i kontrollgruppen. Vi har middels tillit til effektestimatet. • HbA1c konsentrasjoner ble i gjennomsnitt redusert med 1 til 1,5 prosentpoeng mer sammenliknet med standard behandling. Vi har middels tillit til effektestimatet. • Fastende glukosekonsentrasjoner ble redusert. Vi har middels tillit til effektestimatet. • Helserelatert livskvalitet var bare undersøkt i én studie. • KMI ble i gjennomsnitt redusert med 4 til 5 kg/m2 mer i kirurgigruppen sammenliknet med standard behandling. Vi har middels tillit til effektestimatet. Effekt og sikkerhet utover to år var ikke rapportert. • I registerstudien ble det rapportert at 30- dagers dødelighet, alvorlig morbiditet og sammensatt morbiditet var henholdsvis 0,15 %, 0,7 % og 4,2 % blant 1300 opererte pasienter. • Fedmekirurgi koster mellom 83 500 og 118 000 kroner per pasient i året behandlingen gis, mens livsstilsbehandling koster mellom 23 400 og 52 200 kroner per pasient i helsetjenesteperspektivet. Fedmekirurgi ved diabetes type 2 og KMI under 35 kan gi tilbakegang av diabetes. På grunn av kort oppfølgingstid i studiene er det vanskelig å forutsi hvordan fedmekirurgi påvirker framtidige helseeffekter og helsekostnader ved diabetes. Effekt og sikkerhet utover to år bør undersøkes i videre studier.

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