| 1. |
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| 2. |
- Forsberg, Anna, et al.
(author)
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Once-only colonoscopy or two rounds of faecal immunochemical testing 2 years apart for colorectal cancer screening (SCREESCO): preliminary report of a randomised controlled trial
- 2022
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In: The Lancet Gastroenterology & Hepatology. - : ELSEVIER INC. - 2468-1253. ; 7:6, s. 513-521
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Journal article (peer-reviewed)abstract
- Background Screening for colorectal cancer is done with lower gastrointestinal endoscopy or stool-based tests. There is little evidence from randomised trials to show primary colonoscopy reduces mortality in colorectal cancer We aimed to investigate the effect of screening with once-only colonoscopy or two rounds of faecal immunochemical test screening on colorectal cancer mortality and incidence. Methods We did a randomised controlled trial in Sweden (SCREESCO). Residents in 18 of 21 regions who were age 60 years in the year of randomisation were identified from a population register maintained by the Swedish Tax Agency. A statistician with no further involvement in the trial used a randomised block method to assign individuals to once-only colonoscopy, two rounds of faecal immunochemical testing (OC-Sensor; 2 years apart), or a control group (no intervention; standard diagnostic pathways), in a ratio of 1:6 for colonoscopy versus control and 1:2 for faecal immunochemical testing versus control. Masking was not possible due to the nature of the trial. The primary endpoints of the trial are colorectal cancer mortality and colorectal cancer incidence. Here, we report preliminary participation rates, baseline findings, and adverse events from March, 2014, to December, 2020, in the two intervention groups after completion of recruitment and screening, up to the completion of the second faecal immunochemical testing round. Analyses were done in the intention-to-screen population, defined as all individuals who were randomly assigned to the respective study group. This study is registered with Clinical Trials.gov, NCT02078804. Findings Between March 1, 2014, and Dec 31, 2020, 278 280 people were induded in the study; 31 140 were assigned to the colonoscopy group, 60 300 to the faecal immunochemical test group, and 186 840 to the control group. 10 679 (35.1%) of 30 400 people who received an invitation for colonoscopy participated. 33 383 (55.5%) of 60 137 people who received a postal faecal immunochemical test participated. In the intention-to-screen analysis, colorectal cancer was detected in 49 (0.16%) of 31140 people in the colonoscopy group versus 121 (0. 20%) of 60 300 in the faecal immunochemical test group (relative risk [RR] 0.78, 95% CI 0.56-1.09). Advanced adenomas were detected in 637 (2.05%) people in the colonoscopy group and 968 (1.61%) in the faecal immunochemical test group (RR 1.27, 95% CI 1.15-1.41). Colonoscopy detected more right-sided advanced adenomas than faecal immunochemical testing. There were two perforations and 15 major bleeds in 16 555 colonoscopies. No intervention-related deaths occurred. Interpretation The diagnostic yield and the low number of adverse events indicate that the design from this trial, both for once-only colonoscopy and faecal immunochemical test screening, could be transferred to a population-based screening service if a benefit in disease-specific mortality is subsequently shown. Copyright (C) 2022 Elsevier Ltd. All rights reserved.
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| 3. |
- Sundström, Johan, Professor, 1971-, et al.
(author)
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Risk factors for subarachnoid haemorrhage : a nationwide cohort of 950 000 adults
- 2019
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In: International Journal of Epidemiology. - : Oxford University Press. - 0300-5771 .- 1464-3685. ; 48:6, s. 2018-2025
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Journal article (peer-reviewed)abstract
- BACKGROUND: Subarachnoid haemorrhage (SAH) is a devastating disease, with high mortality rate and substantial disability among survivors. Its causes are poorly understood. We aimed to investigate risk factors for SAH using a novel nationwide cohort consortium.METHODS: We obtained individual participant data of 949 683 persons (330 334 women) between 25 and 90 years old, with no history of SAH at baseline, from 21 population-based cohorts. Outcomes were obtained from the Swedish Patient and Causes of Death Registries.RESULTS: During 13 704 959 person-years of follow-up, 2659 cases of first-ever fatal or non-fatal SAH occurred, with an age-standardized incidence rate of 9.0 [95% confidence interval (CI) (7.4-10.6)/100 000 person-years] in men and 13.8 [(11.4-16.2)/100 000 person-years] in women. The incidence rate increased exponentially with higher age. In multivariable-adjusted Poisson models, marked sex interactions for current smoking and body mass index (BMI) were observed. Current smoking conferred a rate ratio (RR) of 2.24 (95% CI 1.95-2.57) in women and 1.62 (1.47-1.79) in men. One standard deviation higher BMI was associated with an RR of 0.86 (0.81-0.92) in women and 1.02 (0.96-1.08) in men. Higher blood pressure and lower education level were also associated with higher risk of SAH.CONCLUSIONS: The risk of SAH is 45% higher in women than in men, with substantial sex differences in risk factor strengths. In particular, a markedly stronger adverse effect of smoking in women may motivate targeted public health initiatives.
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| 4. |
- Bränström, Robert, et al.
(author)
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Electrical short-circuit in β-cells from a patient with non-insulinoma pancreatogenous hypoglycemic syndrome (NIPHS) : a case report
- 2010
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In: Journal of Medical Case Reports. - : Springer Science and Business Media LLC. - 1752-1947. ; 4:1, s. 315-
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Journal article (peer-reviewed)abstract
- INTRODUCTION: Non-insulinoma pancreatogenous hypoglycemic syndrome is a rare disorder among adults, and, to our knowledge, only about 40 cases have been reported in the literature. CASE PRESENTATION: The patient is a previously healthy 35-year-old Caucasian man. His symptoms began four years ago when he suddenly felt weakness in his legs and started sweating for unknown reasons. The symptoms worsened, and laboratory tests revealed hypoglycemia and hyperinsulinemia at the time of the symptoms. All diagnostics attempts using magnetic resonance imaging, computed tomography, and endoscopic ultrasound did not reveal any abnormalities. At this stage, surgical intervention was planned, and a distal 80% pancreatectomy was performed. The histopathologic and immunohistochemical investigations of the pancreas showed an increased number of islets of different sizes, more or less evenly distributed in the gland, but no insulinoma. Patch-clamp recordings from isolated pancreatic β-cells showed that, even at a low glucose concentration (3 mmol/L), the β-cell membrane was depolarized, and action potentials were seen. Surprisingly, in patch-clamp experiments, the addition of diazoxide had a marked effect on K-ATP channel activity and membrane potential, but no effect on insulin levels in vivo before surgery. CONCLUSION: This case report adds new information on the pathogenesis of non-insulinoma pancreatogenous hypoglycemic syndrome, as we performed an electrophysiologic characterization of isolated islet cells. We show, for the first time, that β-cells isolated from a non-insulinoma pancreatogenous hypoglycemic syndrome patient are constantly depolarized, even at low glucose levels, but display normal K-ATP channel physiology.
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| 5. |
- Lu, Ming, et al.
(author)
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Expression and association of TRPC subtypes with Orai1 and STIM1 in human parathyroid
- 2010
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In: Journal of Molecular Endocrinology. - 0952-5041 .- 1479-6813. ; 44:5, s. 285-294
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Journal article (peer-reviewed)abstract
- The mechanism behind Ca2+ entry into the parathyroid cells has been widely debated, and the molecular identities of the responsible ion channels have not been established yet. In this study, we show that the parathyroid cells lack voltage-operated Ca2+ channels. Passive store depletion by thapsigargin, on the other hand, induces a large non-voltage-activated non-selective cation current. The increase in intracellular Ca2+ caused by thapsigargin is attenuated by 2-aminoethoxydiphenyl borate, a blocker of store-operated Ca2+ entry (SOCE). Candidate molecules for non-voltage-operated Ca2+ signaling were investigated. These included members of the transient receptor potential canonical (TRPC) ion channel family, as well as Ca2+ release-activated Ca2+ modulator 1 (Orai1) and stromal interaction molecule 1 (STIM1) that are key proteins in the SOCE pathway. Using RT-PCR screening, quantitative real-time PCR, and western blot, we showed expression of TRPC1, TRPC4, and TRPC6; Orai1; and STIM1 genes and proteins in normal and adenomatous human parathyroid tissues. Furthermore, co-immunoprecipitation experiments demonstrated a ternary complex of TRPC1-Orai1-STIM1, supporting a physical interaction between these molecules in human parathyroid.
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| 6. |
- Andréasson, Maia, 1960, et al.
(author)
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Swedish CLARIN activities
- 2009
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In: Proceedings of the Nodalida 2009 workshop on CLARIN activities in the Nordic countries. NEALT Proceedings Series. - 1736-6305. ; 5, s. 1-5
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Conference paper (peer-reviewed)
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| 7. |
- Andréasson, Maia, et al.
(author)
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Swedish CLARIN Activities
- 2009
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In: Proceedings of the NODALIDA 2009 workshop Nordic Perspectives on the CLARIN Infrastructure of Language Resources. - : Northern European Association for Language Technology (NEALT). ; , s. 1-5
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Conference paper (peer-reviewed)abstract
- Although Sweden has yet to allocate funds specifically intended for CLARIN activities, there are some ongoing activities which are directly relevant to CLARIN, and which are explicitly linked to CLARIN. These activities have been funded by the Committee for Research Infrastructures and its subcommittee DISC (Database Infrastructure Committee) of the Swedish Research Council.
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| 8. |
- Artman, Henrik, 1968-, et al.
(author)
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Effektiv miljötillsyn : slutrapport
- 2013
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Reports (other academic/artistic)abstract
- Målsättningen har varit att ta fram ny kunskap inom miljötillsynen och därigenom uppnå en effektivare miljötillsyn samt att få in nya vetenskapliga perspektiv på miljötillsyn.I rapporten studeras metoder för inspektioner och det kommunikativa samspelet mellan inspektören och företrädare för den verksamhet som inspekteras, hur den institutionella ramen för inspektionsprocessen fungerar samt visar på möjligheter att mäta effekterna av inspektioner och tillsyn.Naturvårdsverket kommer att ha resultatet som ett kunskapsunderlag i fortsatt arbete med tillsynsvägledning och utveckling av hur tillsyn och tillsynsvägledning kan följas upp och utvärderas.
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Eriksson, Anders, 1971-
(author)
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Essays on Gaussian Probability Laws with Stochastic Means and Variances : With Applications to Financial Economics
- 2005
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Doctoral thesis (other academic/artistic)abstract
- This work consists of four articles concerning Gaussian probability laws with stochastic means and variances. The first paper introduces a new way of approximating the probability distribution of a function of random variables. This is done with a Gaussian probability law with stochastic mean and variance. In the second paper an extension of the Generalized Hyperbolic class of probability distributions is presented. The third paper introduces, using a Gaussian probability law with stochastic mean and variance, a GARCH type stochastic process with skewed innovations. In the fourth paper a Lévy process with second order stochastic volatility is presented, option pricing under such a process is also considered.
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| 13. |
- Eriksson, Jan W., et al.
(author)
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Effects of dapagliflozin and n-3 carboxylic acids on non-alcoholic fatty liver disease in people with type 2 diabetes: a double-blind randomised placebo-controlled study
- 2018
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In: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 61:9, s. 1923-1934
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Journal article (peer-reviewed)abstract
- Aims/hypothesis The EFFECT-II study aimed to investigate the effects of dapagliflozin and omega-3 (n-3) carboxylic acids (OM-3CA). individually or combined, on liver fat content in individuals with type 2 diabetes and non-alcoholic fatty liver disease (NAFLD). Methods This randomised placebo-controlled double-blind parallel-group study was performed at five clinical research centres at university hospitals in Sweden. 84 participants with type 2 diabetes and NAFLD were randomly assigned 1:1:1:1 to four treatments by a centralised randomisation system, and all participants as well as investigators and staff involved in the study conduct and analyses were blinded to treatments. Each group received oral doses of one of the following: 10 mg dapagliflozin (n = 21). 4 g OM3-CA (n = 20), a combination of both (n = 22) or placebo (n = 21). The primary endpoint was liver fat content assessed by MRI (proton density fat fraction [PDFF]) and, in addition, total liver volume and markers of glucose and lipid metabolism as well as of hepatocyte injury and oxidative stress were assessed at baseline and after 12 weeks of treatment (completion of the trial). Results Participants had a mean age of 65.5 years (SD 5.9), BMI 31.2 kg/m(2) (3.5) and liver PDFF 18% (9.3). All active treatments significantly reduced liver PDFF from baseline, relative changes: OM-3CA, -15%; dapagliflozin, -13%; OM-3CA + dapagliflozin, -21%. Only the combination treatment reduced liver PDFF (p = 0.046) and total liver fat volume (relative change, -24%,p = 0.037) in comparison with placebo. There was an interaction between the PNPLA31148M polymorphism and change in liver PDFF in the active treatment groups (p = 0.03). Dapagliflozin monotherapy, but not the combination with OM-3CA, reduced the levels of hepatocyte injury biomarkers, including alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transfcrase (gamma-GT), cytokeratin (CK) 18-M30 and CK 18-M65 and plasma fibroblast growth factor 21 (FGF21). Changes in gamma-GT correlated with changes in liver PDFF (rho = 0.53, p = 0.02). Dapagliflozin alone and in combination with OM-3CA improved glucose control and reduced body weight and abdominal fat volumes. Fatty acid oxidative stress biomarkers were not affected by treatments. There were no new or unexpected adverse events compared with previous studies with these treatments. Conclusions/interpretation Combined treatment with dapagliflozin and OM-3CA significantly reduced liver fat content. Dapagliflozin monotherapy reduced all measured hepatocyte injury biomarkers and FGF21, suggesting a disease-modifying effect in NAFLD.
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| 14. |
- Forsberg, Anna, 1969, et al.
(author)
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Experiencing liver transplantation: a phenomenological approach.
- 2000
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In: Journal of advanced nursing. - 0309-2402. ; 32:2, s. 327-34
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Journal article (peer-reviewed)abstract
- In order to promote health, nurses and other health care professionals need to discover and articulate the meaning that is implicit in experiencing life after liver transplantation. From such an understanding, appropriate nursing interventions can be based. The aim of this study was to investigate the subjective experiences of the meaning of having a liver transplant, 1 year after the transplantation. After approval from the ethics committee at Goteborg University, 12 patients, nine women and three men, were interviewed. The study sample was chosen strategically to represent common diagnoses preceding liver transplantation. A phenomenological approach was chosen for the study. Analyses of the interviews were based on a modified version of a phenomenological method by Karlsson. Seven categories emerged: facing the inevitable; recapturing the body; emotional chaos; leaving the experts; family and friends; the threat of graft rejection; and honouring the donor. Having undergone a liver transplant meant living in a paradoxical situation. Knowing that you survived, it was a struggle to regain physical strength under great emotional stress. The recipients had to self-administer life-long medication, recognize symptoms indicating a potential problem and monitor for the possibility of graft rejection. Social support was essential for recovery. Meeting others with the same experience helped liver-transplanted patients to deal with their identity crises as well as undergo a transformation from being utterly unique to a survivor among others. The clinical implications from this study are that interventions, such as patient education, and social and mental support, are important tools to optimize both self-care capacity and the ability to maintain a healthy perception of identity after having a liver transplant at least up to 12 months post-transplant.
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| 15. |
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| 16. |
- Forsberg, Anders, et al.
(author)
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Landmark-Based Software for Anatomical Measurements : A Precision Study
- 2009
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In: Clinical anatomy (New York, N.Y. Print). - : Wiley. - 0897-3806 .- 1098-2353. ; 22:4, s. 456-462
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Journal article (peer-reviewed)abstract
- The aim of this study was to develop a software program, called Landmarker, which would aid studies of complex anatomical morphometry by simplifying the manual identification of landmarks in 3D images. We also tested its precision on routine magnetic resonance imaging (MRI) scans. To understand human biological variation, there is a need to identify morphological characteristics from the exterior and the interior of human anatomy. MRI, as opposed to other radiographic methods (mainly based on X-ray techniques), supplies good soft tissue contrast, which allows for more complex assessments than what bony landmarks can provide. Because automation of this assessment is highly demanding, one of the primary goals for the new software was to enable more rapid identification of landmark sets in 3D image data. Repeat acquisition of head MRIs having a resolution of 0.94 x 0.94 x 1.20 mm3 were performed on 10 volunteers. Intra- and interoperator, as well as interacquisition variations of manual identification of exterior, craniofacial interior, and brain landmarks were studied. The average distances between landmarks were <1.8 mm, <2.3 mm, and <2.0 mm in the intra- and interoperator, and interacquisition evaluations, respectively. This study presents new software for time efficient identification of complex craniofacial landmarks in 3D MRI. To the best of our knowledge, no evaluation of software for rapid landmark-based analysis of complex anatomies from 3D MR data has yet been presented. This software may also be useful for studies in other anatomical regions and for other types of image data.
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| 17. |
- Forsberg, Anton, et al.
(author)
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Low background and high contrast PET imaging of amyloid-β with [11C]AZD2995 and [11C]AZD2184 in Alzheimer's disease patients
- 2013
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In: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer-Verlag New York. - 1619-7070 .- 1619-7089. ; 40:4, s. 580-593
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Journal article (peer-reviewed)abstract
- PURPOSE: The aim of this study was to evaluate AZD2995 side by side with AZD2184 as novel PET radioligands for imaging of amyloid-β in Alzheimer's disease (AD).METHODS: In vitro binding of tritium-labelled AZD2995 and AZD2184 was studied and compared with that of the established amyloid-β PET radioligand PIB. Subsequently, a first-in-human in vivo PET study was performed using [(11)C]AZD2995 and [(11)C]AZD2184 in three healthy control subjects and seven AD patients.RESULTS: AZD2995, AZD2184 and PIB were found to share the same binding site to amyloid-β. [(3)H]AZD2995 had the highest signal-to-background ratio in brain tissue from patients with AD as well as in transgenic mice. However, [(11)C]AZD2184 had superior imaging properties in PET, as shown by larger effect sizes comparing binding potential values in cortical regions of AD patients and healthy controls. Nevertheless, probably due to a lower amount of nonspecific binding, the group separation of the distribution volume ratio values of [(11)C]AZD2995 was greater in areas with lower amyloid-β load, e.g. the hippocampus.CONCLUSION: Both AZD2995 and AZD2184 detect amyloid-β with high affinity and specificity and also display a lower degree of nonspecific binding than that reported for PIB. Overall [(11)C]AZD2184 seems to be an amyloid-β radioligand with higher uptake and better group separation when compared to [(11)C]AZD2995. However, the very low nonspecific binding of [(11)C]AZD2995 makes this radioligand potentially interesting as a tool to study minute levels of amyloid-β. This sensitivity may be important in investigating, for example, early prodromal stages of AD or in the longitudinal study of a disease modifying therapy.
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| 18. |
- Forsberg, Hans, et al.
(author)
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Oral health in the adult population of Västerbotten, Sweden - a comparison between an epidemiological survery and data obtained from digital dental records
- 2008
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In: Swedish Dental Journal: Oral health in the adult population of Västerbotten, Sweden - a comparison between an epidemiological survey and data obtained from digital records.. ; 32, s. 17-25
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Journal article (peer-reviewed)abstract
- The objective of this study was to analyse the possibilities and limitations of using data drawn from electronic dental patient records (EDPRs) in monitoring dental health among adults in a northern Swedish county. Material and Methods: The study population comprised all 35-, 50-, 65- and 75-year-old patients who were examined and, where required, received treatment at the Public Dental Service (PDS) in Västerbotten, Sweden, in 2003 and in 2004. In total 2,497 patients in 2003, and 2,546 patients in 2004 met the inclusion criteria. As controls, 779 subjects randomly drawn from the adult population in the same age groups and from the same county were used. They participated in an oral health survey and were examined clinically between October 2002 and March 2003. Results: When oral health was estimated based on EDPRs the prevalence of edentulous subject was significantly underestimated, while the mean numbers of teeth and the mean values of sound teeth were significantly overestimated. No statistically significant difference was found in prevalence of primary decayed tooth surfaces (DS). The prevalence of filled teeth (FT) was fairly similar between the study samples. Registrations of periodontal status were mainly missing in the EDPRs. Since registrations related to temporomandibular disorders are not included in the T4 system its prevalence could no be assessed and accordingly not compared with the epidemiological sample. Conclusion: The study shows that clinical registration based on EDPRs is at present not accurate enough to be used as indicators of oral health status among adults in a community.The objective of this study was to analyse the possibilities and limitations of using data drawn from electronic dental patient records (EDPRs) in monitoring dental health among adults in a northern Swedish county. Material and Methods: The study population comprised all 35-, 50-, 65- and 75-year-old patients who were examined and, where required, received treatment at the Public Dental Service (PDS) in Västerbotten, Sweden, in 2003 and in 2004. In total 2,497 patients in 2003, and 2,546 patients in 2004 met the inclusion criteria. As controls, 779 subjects randomly drawn from the adult population in the same age groups and from the same county were used. They participated in an oral health survey and were examined clinically between October 2002 and March 2003. Results: When oral health was estimated based on EDPRs the prevalence of edentulous subject was significantly underestimated, while the mean numbers of teeth and the mean values of sound teeth were significantly overestimated. No statistically significant difference was found in prevalence of primary decayed tooth surfaces (DS). The prevalence of filled teeth (FT) was fairly similar between the study samples. Registrations of periodontal status were mainly missing in the EDPRs. Since registrations related to temporomandibular disorders are not included in the T4 system its prevalence could no be assessed and accordingly not compared with the epidemiological sample. Conclusion: The study shows that clinical registration based on EDPRs is at present not accurate enough to be used as indicators of oral health status among adults in a community.
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| 19. |
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| 20. |
- Hsu, Chih-Wei, et al.
(author)
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Controlled Growth of GaN Pyramidal template hosting InGaN Quantum Dots
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Other publication (other academic/artistic)abstract
- The emission properties of InGaN grown on hexagonal GaN pyramids with various pitch distances (PD) are studied. Emissions associated with InGaN quantum wells (QWs) and InGaN quantum dots (QDs) can be identified. The emission energies of InGaN QWs and QDs shift toward opposite directions with increasing PD; red-shift for QWs and blue-shift for QDs. Based on the source supply mechanism in a selective area growth process, the formation of InGaN QDs on GaN pyramids is believed to be a combined effect of Stranski-Krastanow growth mode and spinodal decomposition taking place at the microscopic (0001) surfaces on GaN pyramids.
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| 21. |
- Janson, Martin S., et al.
(author)
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Hydrogen in the wide bandgap semiconductor silicon carbide
- 2004
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In: Physica Scripta. - 0031-8949 .- 1402-4896. ; T108, s. 99-112
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Journal article (peer-reviewed)abstract
- In this paper we give a review of our recent results related to the incorporation of hydrogen (H) in silicon carbide (SiC) and its interaction with acceptor doping atoms and implantation induced defects. Hydrogen is an abundant impurity in the growth of epitaxial SiC since it is present in the precursor gases and since H-2 is used as the carrier gas. High concentrations of hydrogen are indeed incorporated into highly doped p-type epi-layers and it is shown that the main source is the carrier gas. Furthermore, it is revealed that the entire substrate becomes homogeneously filled with hydrogen during growth and that this hydrogen is more thermally stable than that in the epi-layer. Incorporation of hydrogen from an H-2 ambient, at temperatures considerably lower than those used for epitaxy, is also demonstrated in p-type samples coated with a catalytic metal film. This effect is most likely the cause for the increased series resistance observed in p-type SiC Schottky sensor devices using a catalytic metal gate after annealing at 600 degrees C in a H-2 containing ambient. Hydrogen is found to passivate the acceptors Al and B by forming electrically neutral H-acceptor complexes. Unlike in Si and GaAs, the two H-acceptor complexes in SiC exhibit very different dissociation energies, suggesting that the atomic configurations of the complexes are significantly different. The migration of mobile hydrogen in the presence of externally applied, or internal built-in, electric fields further reveals that hydrogen is present as H+ in p-type SiC. Finally, the redistribution and subsequent out-diffusion of low energy implanted H-1 and H-2 is investigated. Two annealing phases for the redistribution are observed, and the activation energies for the processes are extracted.
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| 22. |
- Lundskog, Anders
(author)
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Controlled growth of hexagonal GaN pyramids and InGaN QDs
- 2012
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Doctoral thesis (other academic/artistic)abstract
- Gallium-nitride (GaN) and its related alloys are direct band gap semiconductors, with a wide variety of applications. The white light emitting diode (LED) is of particular importance as it is expected to replace energy inefficient light bulb and hazardous incandescent lamps used today. However, today’s planar hetero epitaxial grown LEDs structures contain an unavoidable number of dislocations, which serves as non-radiative recombination centers. The dislocations harm the luminous efficiency of the LEDs and generate additional heat. Pseudomorphically grown quantum dots (QDs) are expected to be dislocation free thus the injected carriers captured by the QDs essentially recombine radiatively since the dislocations remain outside the QD. Furthermore the continuous character of the density of states in bulk materials is redistributed when the size of the dot is reduced within the Bohr radius of the material. Fully discret energy levels are eventually reached, which offers additional control of the optical properties. The Coulomb interaction between the confined carriers also has influence on the emission energy of the recombining carriers, which opens up the possibility of manufacturing novel light sources such as the single photon emitter. Single photon emitters are essential building blocks for quantum cryptography and teleportation applications.The main contribution of the present work is the investigation of growth and characterization of sitecontrolled indium-gallium-nitride QDs embedded in GaN matrixes. The goal has been to demonstrate the ability to grow site-controlled InGaN QDs at the apex of hexagonal GaN pyramids in a controlled way using hot-wall metal organic chemical vapor deposition (MOCVD). Strong emphasis was set on the controlled growth of InGaN QDs. For example the growth of a single InGaN QD located at the apex of hexagonal GaN pyramids with tunable emission energy, the QD emission energy impact on the mask design, and a novel approach for the growth of InGaN QDs with polarization deterministic photon vectors were reported. The thesis is mainly based on experimental investigations by secondary electron microscope (SEM), micro photo-luminescence (μPL), and scanning transition electron microscopy ((S)TEM) characterization techniques.In Paper 1 and 2, we present the growth of symmetric GaN hexagonal pyramids which served as template for the InGaN QDs grown. In paper 1, it was concluded that the selective area growth (SAG) of hexagonal GaN pyramids by MOCVD through symmetric openings in a SIN mask roughly can be divided in two regimes where either the pyramid expands laterally or not. When the pyramid expanded laterally the resulting pyramid apex became (0001) truncated even after prolonged growth times. Lateral expansion also had major impact on the pyramid-to-pyramid uniformity. In paper 2, the MOCVD process parameter impact on the pyramid morphology was investigated. By tuning the growth temperature, the ammonia, and TMGa-flows a self limited pyramid structure with only {1101} facets visible was achieved. The presence of the {1101}, {1102}, and {1100} facets were discussed from surface stabilities under various growth conditions.Paper 3 and 4 concern the growth of InGaN QDs located at the apex of hexagonal GaN pyramids. In paper 3, we showed that it is possible to grow single QDs at the apex of hexagonal pyramids with emission line widths in the Ångström range. The QD emission energy was demonstrated to be tunable by the growth temperature. Basic spectroscopy data is also presented on a single QD in paper 3. In paper 4, the growth mechanisms of the QDs presented in paper 3 are presented. We concluded that (0001) truncated GaN pyramid base initiated the growth of InGaN QDs which gave rise to narrow luminescence peaks in the μPL spectra.In paper 5, the QD emission energy impact of the mask design was investigated. To our big surprise the QD emission energy increased with increasing pyramid pitch while the emission energy of the InGaN quantum wells located on the {1101} facets of the pyramids energetically shifted towards lower energies. The energy shift at the apex was found to be associated with the (0001) truncation diameter of the underlying GaN pyramid since no energy shift was observed for (0001) truncated pyramids with truncation diameters larger than 100 nm.In paper 6, the symmetry of the GaN pyramids were intentionally broken through the introduction of elongated openings in the SiN mask (symmetric openings was used in the previous five papers). The emission polarization vectors of the subsequently grown InGaN QDs were deterministically linked to the in-plane orientation of the pyramid it was nucleated upon, implying that the QDs inhibit an inplane anisotropy directly inherited from the pyramid template.Finally, paper 7 describes a hot-wall MOCVD reactor improvement by inserting insulating pyrolytic boron-nitride (PBN) stripes in the growth chamber. By doing this, we have completely eliminated the arcing problem between different susceptor parts. As a consequence, the reactor gained run-to-run reproducibility. Growth of state of the art advanced aluminum-gallium-nitride high electron mobility transistor structures on a 100 mm wafer with electron mobility above 2000 Vs/cm2 was demonstrated by the improved process.
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| 23. |
- Lundskog, Anders, et al.
(author)
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InGaN quantum dot formation mechanism on hexagonal GaN/InGaN/GaN pyramids
- 2012
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In: Nanotechnology. - : Institute of Physics (IOP). - 0957-4484 .- 1361-6528. ; 23:30, s. 305708-
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Journal article (peer-reviewed)abstract
- Growing InGaN quantum dots (QDs) at the apex of hexagonal GaN pyramids is an elegant approach to achieve a deterministic positioning of QDs. Despite similar synthesis procedures by metal–organic chemical vapor deposition, the optical properties of the QDs reported in the literature vary drastically. The QDs tend to exhibit either narrow or broad emission lines in the micro-photoluminescence spectra. By coupled microstructural and optical investigations, the QDs giving rise to narrow emission lines were concluded to nucleate in association with a (0001) facet at the apex of the GaN pyramid.
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| 24. |
- Lundskog, Anders, et al.
(author)
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Unexpected behavior of InGaN quantum dot emission energy located at apices of hexagonal GaN pyramids
-
Other publication (other academic/artistic)abstract
- InGaN quantum dots (QDs) have been grown at the apices of hexagonal GaN pyramids. The pyramids were selectively grown on a (0001) oriented GaN template through circular apertures in a SiN mask positioned in square arrays. The emission of the InGaN QDs was shifted towards higher energies when the center-to-center distance of the pyramids was increased, while the emission from InGaN quantum wells located on the {1101} facets of the pyramids was energetically shifted towards lower energies. No energy shift was observed for (0001) truncated pyramids with truncation diameters larger than 100 nm.
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| 25. |
- Palisaitis, Justinas, et al.
(author)
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Characterization of InGaN/GaN quantum well growth using monochromated valence electron energy loss spectroscopy
- 2014
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 115:3, s. 034302-
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Journal article (peer-reviewed)abstract
- The early stages of InGaN/GaN quantum wells growth for In reduced conditions have been investigated for varying thickness and composition of the wells. The structures were studied by monochromated STEM–VEELS spectrum imaging at high spatial resolution. It is found that beyond a critical well thickness and composition, quantum dots (>20 nm) are formed inside the well. These are buried by compositionally graded InGaN, which is formed as GaN is grown while residual In is incorporated into the growing structure. It is proposed that these dots may act as carrier localization centers inside the quantum wells.
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| 26. |
- Pihlgren, Karin, et al.
(author)
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Changes in tooth mortality between 1990 and 2002 among adults in Västerbotten County, Sweden : influence of socioeconomic factors, general health, smoking, and dental care habits on tooth mortality
- 2011
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In: Swedish Dental Journal. - 0347-9994. ; 35:2, s. 77-88
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Journal article (peer-reviewed)abstract
- The objectives of the study were to analyse changes in tooth mortality among adults in Västerbotten County, Sweden, between 1990 and 2002 and determine whether socioeconomic factors, general health, smoking, and dental care habits influenced tooth mortality. The study was based on samples drawn from the adult population in Västerbotten County in 1990 and 2002. The studied age groups were 35-, 50-, and 65-year-olds. In 2002 75-year-olds were included. The surveys comprised a clinical examination and a questionnaire.The latter focused on oro-facial symptoms, socioeconomic factors, general health, smoking, and dental care habits. Complete data were obtained from 715 individuals in 1990 and from 768 individuals in 2002.Variables used to depict tooth mortality were edentulousness, occlusal supporting zones (Eichner index), and number of teeth. The prevalence of edentulousness in Västerbotten County decreased from 12.7% in 1990 to 3.7% in 2002 (P < 0.001). The mean number of teeth increased in all age groups between 1990 and 2002, and so did the number of individuals with tooth contact in all occlusal supporting zones and no gaps between teeth. Low educational level, weak economic status, smoking, and irregular visits to the dental clinic were all significantly related to increased tooth mortality. Between 1990 and 2002 tooth mortality decreased significantly in the adult population of Västerbotten County, Sweden. Cross-sectional analysis identified socioeconomic factors, smoking, and irregular use of dental care services as being related to tooth mortality in both 1990 and 2002.
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| 27. |
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| 28. |
- Pozina, Galia, et al.
(author)
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Time-resolved photoluminescence properties of AlGaN/AlN/GaN high electron mobility transistor structures grown on 4H-SiC substrate
- 2008
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 104:11, s. 113513-
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Journal article (peer-reviewed)abstract
- AlGaN/AlN/GaN high electron mobility transistor heterostructures grown by metal-organic chemical vapor deposition have been studied by temperature dependent time-resolved photoluminescence. The AlGaN-related emission is found to be sensitive to the excitation power and to the built-in internal electric field. In addition, this emission shows a shift to higher energy with the reduction in the excitation density, which is rather unusual. Using a self-consistent calculation of the band potential profile, we suggest a recombination mechanism for the AlGaN-related emission involving electrons confined in the triangular AlGaN quantum well and holes weakly localized due to potential fluctuations.
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| 29. |
- Razzaghian, Hamid Reza, et al.
(author)
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Post-Zygotic and Inter-Individual Structural Genetic Variation in a Presumptive Enhancer Element of the Locus between the IL10Rβ and IFNAR1 Genes
- 2013
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:9, s. e67752-
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Journal article (peer-reviewed)abstract
- Although historically considered as junk-DNA, tandemly repeated sequence motifs can affect human phenotype. For example, variable number tandem repeats (VNTR) with embedded enhancers have been shown to regulate gene transcription. The post-zygotic variation is the presence of genetically distinct populations of cells in an individual derived from a single zygote, and this is an understudied aspect of genome biology. We report somatically variable VNTR with sequence properties of an enhancer, located upstream of IFNAR1. Initially, SNP genotyping of 63 monozygotic twin pairs and multiple tissues from 21 breast cancer patients suggested a frequent post-zygotic mosaicism. The VNTR displayed a repeated 32 bp core motif in the center of the repeat, which was flanked by similar variable motifs. A total of 14 alleles were characterized based on combinations of segments, which showed post-zygotic and inter-individual variation, with up to 6 alleles in a single subject. Somatic variation occurred in similar to 24% of cases. In this hypervariable region, we found a clustering of transcription factor binding sites with strongest sequence similarity to mouse Foxg1 transcription factor binding motif. This study describes a VNTR with sequence properties of an enhancer that displays post-zygotic and inter-individual genetic variation. This element is within a locus containing four related cytokine receptors: IFNAR2, IL10R beta, IFNAR1 and IFNGR2, and we hypothesize that it might function in transcriptional regulation of several genes in this cluster. Our findings add another level of complexity to the variation among VNTR-based enhancers. Further work may unveil the normal function of this VNTR in transcriptional control and its possible involvement in diseases connected with these receptors, such as autoimmune conditions and cancer.
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| 30. |
- Schain, Martin, et al.
(author)
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Arterial input function derived from pairwise correlations between PET-image voxels
- 2013
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In: Journal of Cerebral Blood Flow and Metabolism. - : Nature Publishing Group. - 0271-678X .- 1559-7016. ; 33:7, s. 1058-1065
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Journal article (peer-reviewed)abstract
- A metabolite corrected arterial input function is a prerequisite for quantification of positron emission tomography (PET) data by compartmental analysis. This quantitative approach is also necessary for radioligands without suitable reference regions in brain. The measurement is laborious and requires cannulation of a peripheral artery, a procedure that can be associated with patient discomfort and potential adverse events. A non invasive procedure for obtaining the arterial input function is thus preferable. In this study, we present a novel method to obtain image-derived input functions (IDIFs). The method is based on calculation of the Pearson correlation coefficient between the time-activity curves of voxel pairs in the PET image to localize voxels displaying blood-like behavior. The method was evaluated using data obtained in human studies with the radioligands [11C]flumazenil and [11C]AZ10419369, and its performance was compared with three previously published methods. The distribution volumes (VT) obtained using IDIFs were compared with those obtained using traditional arterial measurements. Overall, the agreement in VT was good (~3% difference) for input functions obtained using the pairwise correlation approach. This approach performed similarly or even better than the other methods, and could be considered in applied clinical studies. Applications to other radioligands are needed for further verification.
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| 31. |
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| 32. |
- Segersson, David, et al.
(author)
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Health Impact of PM10, PM2.5 and Black Carbon Exposure Due to Different Source Sectors in Stockholm, Gothenburg and Umea, Sweden
- 2017
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In: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1661-7827 .- 1660-4601. ; 14:7
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Journal article (peer-reviewed)abstract
- The most important anthropogenic sources of primary particulate matter (PM) in ambient air in Europe are exhaust and non-exhaust emissions from road traffic and combustion of solid biomass. There is convincing evidence that PM, almost regardless of source, has detrimental health effects. An important issue in health impact assessments is what metric, indicator and exposure-response function to use for different types of PM. The aim of this study is to describe sectorial contributions to PM exposure and related premature mortality for three Swedish cities: Gothenburg, Stockholm and Umea. Exposure is calculated with high spatial resolution using atmospheric dispersion models. Attributed premature mortality is calculated separately for the main local sources and the contribution from long-range transport (LRT), applying different relative risks. In general, the main part of the exposure is due to LRT, while for black carbon, the local sources are equally or more important. The major part of the premature deaths is in our assessment related to local emissions, with road traffic and residential wood combustion having the largest impact. This emphasizes the importance to resolve within-city concentration gradients when assessing exposure. It also implies that control actions on local PM emissions have a strong potential in abatement strategies.
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| 33. |
- Spohr, Reimar, et al.
(author)
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Stroke Asymmetry of Tilted Superhydrophobic Ion Track Textures
- 2010
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 26:9, s. 6790-6796
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Journal article (peer-reviewed)abstract
- The stroke asymmetry of contact tingles of water drops on tilted hydrophobic textures is demonstrated, obtained by ion track etching followed by a hydrophobic treatment. Preliminary trends concerning the advancing and receding contact angles are established, each with and against stroke direction. In rough agreement with Cassie-Baxter theory, the cosines of these four contact angles depend linearly on the wetted area fraction. The etched tracks are randomly distributed on the surface of polycarbonate disks and inclined by 300 with respect to the surface, whereby the aspect ratio of individual etched cones is larger than 10. The morphology of the resulting surface is characterized by randomly shaped flat tops overhanging on one side and gradually falling off on the other side. The area fraction of the supporting tops can be calculated from the number of impinging ions per unit area and the cross section of the etched ion tracks. The top layer of the texture consists of flat, horizontal, irregularly shaped tops supporting water drops in the Cassie-Baxter state. With increasing etching time, the texture becomes increasingly defied. To fabricate the textures, we irradiated polyearbonate with 5 x 10(7) Br-80(7+) ions/cm(2) of 30 MeV total energy (having a range of about 20 mu m in polycarbonate) at a tilt angle of 30 with respect to the sample surface and etched the latent ion tracks selectively. The textured surface is made hydrophobic by carbondifluoride radicals (CF2) resulting from the decay of octafluorocyclobutane, C4F8, in a plasma reactor. The goal of the report is to show that the tilt orientation of a superhydrophobic surface leads to advancing and receding contact angles depending on the orientation with and against the stroke direction. In addition, a rotating movement is demonstrated qualitatively by floating a rotationally asymmetric disk on an ultrasonic bath, similarly treated after an irradiation with (1.2 +/- 0.4) x 10(7) Xe-129(274) MeV/cm- of 8.3 MeV/nucleon at an angle of 45 degrees, whereby the superhydrophobic side of the disk points downward to the water of the ultrasonic bath.
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| 34. |
- Sundström, Anders, et al.
(author)
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Association of suicide attempts with acne and treatment with isotretinoin : retrospective Swedish cohort study
- 2010
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In: BMJ (Clinical research ed.). - : BMJ. - 1756-1833 .- 0959-8138 .- 1468-5833. ; 341, s. c5812-
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To assess the risk of attempted suicide before, during, and after treatment with isotretinoin for severe acne.DESIGN: Retrospective cohort study linking a named patient register of isotretinoin users (1980-9) to hospital discharge and cause of death registers (1980-2001).SETTING: Sweden, 1980-2001. Population 5756 patients aged 15 to 49 years prescribed isotretinoin for severe acne observed for 17 197 person years before, 2905 person years during, and 87 120 person years after treatment.MAIN OUTCOME MEASURES: Standardised incidence ratio (observed number divided by expected number of suicide attempts standardised by sex, age, and calendar year), calculated up to three years before, during, and up to 15 years after end of treatment.RESULTS: 128 patients were admitted to hospital for attempted suicide. During the year before treatment, the standardised incidence ratio for attempted suicide was raised: 1.57 (95% confidence interval 0.86 to 2.63) for all (including repeat) attempts and 1.36 (0.65 to 2.50) counting only first attempts. The standardised incidence ratio during and up to six months after treatment was 1.78 (1.04 to 2.85) for all attempts and 1.93 (1.08 to 3.18) for first attempts. Three years after treatment stopped, the observed number of attempts was close to the expected number and remained so during the 15 years of follow-up: standardised incidence ratio 1.04 (0.74 to 1.43) for all attempts and 0.97 (0.64 to 1.40) for first attempts. Twelve (38%) of 32 patients who made their first suicide attempt before treatment made a new attempt or committed suicide thereafter. In contrast, 10 (71%) of the 14 who made their first suicide attempt within six months after treatment stopped made a new attempt or committed suicide during follow-up (two sample test of proportions, P=0.034). The number needed to harm was 2300 new six month treatments per year for one additional first suicide attempt to occur and 5000 per year for one additional repeat attempt.CONCLUSIONS: An increased risk of attempted suicide was apparent up to six months after the end of treatment with isotretinoin, which motivates a close monitoring of patients for suicidal behaviour for up to a year after treatment has ended. However, the risk of attempted suicide was already rising before treatment, so an additional risk due to the isotretinoin treatment cannot be established. As patients with a history of suicide attempts before treatment made new attempts to a lesser extent than did patients who started such behaviour in connection with treatment, patients with severe acne should not automatically have isotretinoin treatment withheld because of a history of attempted suicide.
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| 35. |
- Svensson, Anna C., et al.
(author)
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Cohort profile : the Stockholm public health cohort
- 2013
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In: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 42:5, s. 1263-1272
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Journal article (peer-reviewed)abstract
- The Stockholm Public Health Cohort was set up within the Stockholm County Council public health surveys to inform on determinants and consequences of significant contributors to the current burden of disease. Participants are 89 268 randomly selected individuals from the adult population of Stockholm County. Baseline surveys took place in 2002, 2006 and 2010 via self-administered questionnaires. So far, participants recruited in 2002 were re-surveyed twice, in 2007 and 2010, and those enrolled in 2006 were re-surveyed once, in 2010. Self-reported data are regularly supplemented by information from national and regional health data and administrative registers, for study participants and their relatives (including their offspring). Available data are extensive and include a wide array of health, lifestyle, perinatal, demographic, socio-economic and familial factors. The cohort is an international resource for epidemiological research, and the data available to the research community for specific studies obtained approval from the Stockholm Public Health Cohort Steering Committee and the Stockholm Regional Ethical Review Board.
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| 36. |
- Wallenquist, Ulrika, 1975-, et al.
(author)
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Grafted neural progenitors migrate and form neurons after experimental traumatic brain injury
- 2009
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In: Restorative Neurology and Neuroscience. - Amsterdam : IOS Press. - 0922-6028 .- 1878-3627. ; 27:4, s. 323-334
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Journal article (peer-reviewed)abstract
- PURPOSENeural stem and progenitor cells (NSPC) generate neurons and glia, a feature that makes them attractive for cell replacement therapies. However, efforts to transplant neural progenitors in animal models of brain injury typically result in high cell mortality and poor neuronal differentiation.METHODSIn an attempt to improve the outcome for grafted NSPC after controlled cortical impact we transplanted Enhanced Green Fluorescent Protein (EGFP)-positive NSPC into the contra lateral ventricle of mice one week after injury.RESULTSGrafted EGFP-NSPC readily migrated to the injured hemisphere where we analyzed the proportion of progenitors and differentiated progeny at different time points. Transplantation directly into the injured parenchyma, resulted in few brains with detectable EGFP-NSPC. On the contrary, in more than 90% of the mice that received a transplant into the lateral ventricle detectable EGFP-positive cells were found. The cells were integrated into the lateral ventricle wall of the un-injured hemisphere, throughout the corpus callosum, and in the cortical perilesional area. At one-week post transplantation, grafted cells that had migrated to the perilesion area mainly expressed markers of neural progenitors and neurons, while in the corpus callosum and the ventricular lining, grafted cells with a glial fate were more abundant. After 3 months, grafted cells in the perilesion area were less abundant whereas cells that had migrated to the walls of the third- and lateral- ventricle of the injured hemisphere were still detectable, suggesting that the injury site remained a hostile environment.CONCLUSIONTransplantation to the lateral ventricle, presumably for being a neurogenic region, provides a favorable environment improving the outcome for grafted NSPC both in term of their appearance at the cortical site of injury, and their acquisition of neural markers.
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| 37. |
- Wallenquist, Ulrika, et al.
(author)
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Ibuprofen attenuates the inflammatory response and allows formation of migratory neuroblasts from grafted stem cells after traumatic brain injury
- 2012
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In: Restorative Neurology and Neuroscience. - 0922-6028 .- 1878-3627. ; 30:1, s. 9-19
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Journal article (peer-reviewed)abstract
- Purpose: There is hope for neural stem and progenitor cells (NSPC) to enhance regeneration when transplanted to the injured brain after traumatic brain injury (TBI). So far, the therapeutic effects of NSPC transplantation have been hampered mainly by the notable death of the transplanted cells. Neuroinflammation may lead to additional cell death after TBI and we hypothesized that survival of grafted NSPC could be enhanced by anti-inflammatory treatment. Methods: Mice that were subjected to controlled cortical impact TBI and grafted with NSPC, were treated with the non-steroidal anti-inflammatory drug ibuprofen. Results: Ibuprofen was found to down-regulate the TBI-induced inflammatory response. In addition, migrating neuroblasts from transplanted cells were observed near the contusion and in the ipsilateral hippocampus in ibuprofen-treated animals only, suggesting that the anti-inflammatory treatment had beneficial effects on graft survival and/or differentiation. However, Morris Water Maze performance or TBI-induced tissue loss was not influenced by ibuprofen treatment. Conclusions: Our data suggests that anti-inflammatory strategies may be a complement to enhance the outcome for the cell transplants following TBI.
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| 38. |
- Wallenquist, Ulrika, 1975-
(author)
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Neural Stem and Progenitor Cells as a Tool for Tissue Regeneration
- 2009
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Doctoral thesis (other academic/artistic)abstract
- Neural stem and progenitor cells (NSPC) can differentiate to neurons and glial cells. NSPC are easily propagated in vitro and are therefore an attractive tool for tissue regeneration. Traumatic brain injury (TBI) is a common cause for death and disabilities. A fundamental problem following TBI is tissue loss. Animal studies aiming at cell replacement have encountered difficulties in achieving sufficient graft survival and differentiation. To improve outcome of grafted cells after experimental TBI (controlled cortical impact, CCI) in mice, we compared two transplantation settings. NSPC were transplanted either directly upon CCI to the injured parenchyma, or one week after injury to the contralateral ventricle. Enhanced survival of transplanted cells and differentiation were seen when cells were deposited in the ventricle. To further enhance cell survival, efforts were made to reduce the inflammatory response to TBI by administration of ibuprofen to mice that had been subjected to CCI. Inflammation was reduced, as monitored by a decrease in inflammatory markers. Cell survival as well as differentiation to early neuroblasts seemed to be improved. To device a 3D system for future transplantation studies, NSPC from different ages were cultured in a hydrogel consisting of hyaluronan and collagen. Cells survived and proliferated in this culturing condition and the greatest neuronal differentiating ability was seen in cells from the newborn mouse brain. NSPC were also used in a model of peripheral nervous system injury, and xeno-transplanted to rats where the dorsal root ganglion had been removed. Cells survived and differentiated to neurons and glia, furthermore demonstrating their usefulness as a tool for tissue regeneration.
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| 39. |
- Westerberg, Marcus, 1990-, et al.
(author)
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The role of endoscopist adenoma detection rate in in sex differences in colonoscopy findings : cross-sectional analysis of the SCREESCO randomized controlled trial
- 2024
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In: Scandinavian Journal of Gastroenterology. - : Taylor & Francis. - 0036-5521 .- 1502-7708. ; 59:4, s. 503-511
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Journal article (peer-reviewed)abstract
- BackgroundFewer adenomas are detected at colonoscopy in women compared to men and failure to detect adenomas and sessile serrated polyps is associated with an increased risk of post-colonoscopy colorectal cancer. The aim of this study was to investigate whether this was in part due to the greater difficulty of conducting colonoscopy in women, with the difference being more apparent in colonoscopies conducted by less skilled endoscopists.Material and methodsCross-sectional exploratory analysis of data on 16,551 individuals undergoing a primary colonoscopy (PCOL group) or colonoscopy after positive faecal immunochemical test (FIT group) within the randomized controlled trial SCREESCO. Endoscopist adenoma detection rate (ADR; low or high) was determined based on each endoscopist's colonoscopies performed in SCREESCO. In each study group, the relationship between the sex difference in colonoscopy outcome and endoscopist ADR was assessed using multiplicative interaction tests.ResultsEndoscopists performed equally many colonoscopies in men and women (median 52% men). There were no signs of effect modification of the risk ratio of any finding (men vs women) by endoscopist ADR in the PCOL group (p = 0.33) or the FIT group (p = 0.30). The proportion of incomplete index colonoscopies was lower in men than in women in both groups and there was no effect modification by endoscopist ADR in either the PCOL group (p = 0.41) or the FIT group (p = 0.96).ConclusionsThis study provides no evidence that endoscopist skill measured by ADR underlies the sex difference in adenoma detection at colonoscopy. This study has trial number NCT02078804 and is registered with ClinicalTrials.gov.
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