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  • 1.
    Bak, Zoltan
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Unit . Linköping University, Faculty of Health Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Steinvall, Ingrid
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Janerot Sjöberg, Birgitta
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences.
    Cardiac dysfunction after burns2008In: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 34, no 5, p. 603-609Article in journal (Refereed)
    Abstract [en]

    Objectives

    Using transoesophageal echocardiography (TEE) we investigated the occurrence, and the association of possible abnormalities of motion of the regional wall of the heart (WMA) or diastolic dysfunction with raised troponin concentrations, or both during fluid resuscitation in patients with severe burns.

    Patients and methods

    Ten consecutive adults (aged 36–89 years, two women) with burns exceeding 20% total burned body surface area who needed mechanical ventilation were studied. Their mean Baux index was 92.7, and they were resuscitated according to the Parkland formula. Thirty series of TEE examinations and simultaneous laboratory tests for myocyte damage were done 12, 24, and 36 h after the burn.

    Results

    Half (n = 5) the patients had varying grades of leakage of the marker that correlated with changeable WMA at 12, 24 and 36 h after the burn (p ≤ 0.001, 0.044 and 0.02, respectively). No patient had WMA and normal concentrations of biomarkers or vice versa. The mitral deceleration time was short, but left ventricular filling velocity increased together with stroke volume.

    Conclusion

    Acute myocardial damage recorded by both echocardiography and leakage of troponin was common, and there was a close correlation between them. This is true also when global systolic function is not deteriorated. The mitral flow Doppler pattern suggested restrictive left ventricular diastolic function.

  • 2.
    Bak, Zoltan
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthesiology and Surgical Centre, Department of Surgery UHL.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Steinvall, Ingrid
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Janerot Sjöberg, Birgitta
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Hemodynamic Changes During Resuscitation After Burns Using the Parkland Formula2009In: Journal of Trauma, ISSN 0022-5282, E-ISSN 1529-8809, Vol. 66, no 2, p. 329-336Article in journal (Refereed)
    Abstract [en]

    Background: The Parkland formula (2-4 mL/kg/burned area of total body surface area %) with urine output and mean arterial pressure (MAP) as endpoints; for the fluid resuscitation in burns is recommended all over the world. There has recently been a discussion on whether central circulatory endpoints should be used instead, and also whether volumes of fluid should be larger. Despite this, there are few central hemodynamic data available in the literature about the results when the formula is used correctly.

    Methods: Ten burned patients, admitted to our unit early, and with a burned area of >20% of total body sur-face area were investigated at 12, 24, and 36 hours after injury. Using transesophageal echocardiography, pulmonary artery catheterization, and transpulmonary thermodilution to monitor them, we evaluated the cardiovascular coupling when urinary output and MAP were used as endpoints.

    Results: Oxygen transport variables, heart rate, MAP, and left ventricular fractional area, did not change significantly during fluid resuscitation. Left ventricular end-systolic and end-diastolic area and global end-diastolic volume index increased from subnormal values at 12 hours to normal ranges at 24 hours after the burn. Extravascular lung intrathoracal blood volume ratio was increased 12 hours after the burn.

    Conclusions: Preload variables, global systolic function, and oxygen transport recorded simultaneously by three separate methods showed no need to increase the total fluid volume within 36 hours of a major burn. Early (12 hours) signs of central circulatory hypovolemia, however, support more rapid infusion of fluid at the beginning of treatment.

  • 3.
    Edston, Erik
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    van Hage, M
    Mast cell tryptase in postmortem serum - Reference values and confounders2007In: International journal of legal medicine (Print), ISSN 0937-9827, E-ISSN 1437-1596, Vol. 121, no 4, p. 275-280Article in journal (Refereed)
    Abstract [en]

    We have investigated the effects of some factors suspected of inducing spuriously increased tryptase concentrations, specifically sampling site, conjunctival petechial bleeding and prone position at the time of death as indicators of premortem asphyxia, and resuscitation efforts by external cardiac massage. Tryptase was measured in blood from the femoral vein in 60 deaths: 39 control cases who died rapidly (within minutes) from natural causes (sudden cardiac death and acute aortic dissection), 16 with death caused by prolonged asphyxia (traumatic compression of the chest and suffocation due to body position or smothering), and five anaphylactic deaths. In 44 of these cases, tryptase was measured in both heart and femoral blood. Mast cell tryptase was analyzed with a commercial FEIA method (Pharmacia Diagnostics AB, Uppsala, Sweden) measuring both a- and ß-tryptase. Assuming that tryptase values in the control group were gamma distributed, we calculated the upper normal limits for tryptase concentrations in femoral blood. It was found that 95% of the controls had values below 44.3 µg/l (femoral blood), SD 5.27 µg/l. All but one of the anaphylactic deaths had tryptase concentrations exceeding that limit. Tryptase was significantly elevated in femoral blood from anaphylactic deaths (p<0.007), compared with the controls. Also, in the cases where death had occurred due to asphyxia tryptase was elevated in femoral blood (p<0.04). A significant difference in tryptase concentrations was seen between blood from the heart and the femoral vessels (p<0.02) in the whole material (n=44). Tryptase concentrations in femoral blood were not influenced by prone position at death, or resuscitation efforts. It is concluded that asphyxia premortem seems to affect tryptase concentrations, that postmortem tryptase measurements should be done in serum from femoral blood, and that the normal upper limit, covering 95%, is 44.3 µg/l. © 2006 Springer-Verlag.

  • 4.
    Eriksson, Olle
    Linköping University, Department of Mathematics, Statistics. Linköping University, Faculty of Arts and Sciences.
    A new program for fast emission calculations based on the COPERT III modelManuscript (Other academic)
    Abstract [en]

    Emissions from road traffic are hard to measure and therefore usually estimated in models. In this paper the construction of the widely used COPERT III model is examined, and the model is rewritten in mathematical notation. The original COPERT III software is easily handled but is not suitable as an emissiondata generating tool for fast calculations over a broad variety of driving conditions, which is required for sensitivity analysis. An alternative program has been developed to meet the desired properties of such a tool. The construction of the alternative program is discussed together with its new abilities and restrictions. Some differences between the results from the original COPERT III software and the alternative program are analyzed and discussed.

  • 5.
    Eriksson, Olle
    Linköping University, Department of Mathematics, Statistics. Linköping University, Faculty of Arts and Sciences.
    Basic sensitivity analysis methods: applied to the COPERT III road traffic emission modelManuscript (Other academic)
    Abstract [en]

    Many complex systems are simulated in models, and these models are hard to evaluate completely. For example, the sensitivity of the model output for different inputs is seldom analyzed. This paper provides an introduction to sensitivity analysis and proposes some basic sensitivity analysis methods. The results are important, for example, in choosing a sampling scheme. Themethods are applied to the COPERT III model, and the sensitivity results are compared and discussed. Certain theoretical results simplify the sensitivity analysis in a special case, and the paper ends by recommending a method.

  • 6.
    Eriksson, Olle
    Linköping University, Department of Mathematics, Statistics. Linköping University, Faculty of Arts and Sciences.
    Global sensitivity analysis methods using response surface descriptions: applied to the COPERT III road traffic emission modelManuscript (Other academic)
    Abstract [en]

    Sensitivity analyses may be local or global, one at a time or all at a time, or classified in other ways. This paper examines some response surface methods for instant calculations of many sensitivities at the same time. The appropriateness of replacing the original model with a simpler response surface is discussed.The methods are also compared with one at a time methods. Sensitivity results are calculated by applying the methods to the COPERT III model. The conclusion is that a simple response surface method should be preferred.

  • 7.
    Eriksson, Olle
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Mathematics, Statistics .
    Känslighetsanalys av personbilars avgasemissioner2003In: Transportforum 2003,2003, 2003Conference paper (Other academic)
  • 8.
    Eriksson, Olle
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Mathematics, Statistics.
    Sensitivity analysis methods for road traffic emission models2004Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Many systems, and some of their properties, are studied in simulation models. The models may be very complex and difficult to understand if the systems they are meant to simulate are complex in themselves. Even small, simple and well-described models can have properties that cannot easily be seen in the model formulations. Sensitivity and uncertainty in the model results are examples of such properties.

    One important field where simulation models are used is road traffic, for emissions or other traffic-related topics. To <late, little has been written about sensitivity and uncertainty in road traffic emission models. More must be known about the construction of such models before sensitivity methods can be proposed.

    This thesis describes one model for road traffic emissions, both for construction and for ability to be an emission data generating tool for the analyses that follow. Some suitable sensitivity methods are studied; they are based on different approaches such as sensitivity on the margins and measure over all situations by using response surface methods. All of the methods in the study are also applied to the described emission model.

    Different approaches are compared on theoretical grounds in several ways, and the sensitivity results allow many other comparisons.

  • 9.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Sensitivity and Uncertainty Analysis Methods: with Applications to a Road Traffic Emission Model2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    There is always a need to study the properties of complex input–output systems, properties that may be very difficult to determine. Two such properties are the output’s sensitivity to changes in the inputs and the output’s uncertainty if the inputs are uncertain.

    A system can be formulated as a model—a set of functions, equations and conditions that describe the system. We ultimately want to study and learn about the real system, but with a model that approximates the system well, we can study the model instead, which is usually easier. It is often easier to build a model as a set of combined sub-models, but good knowledge of each sub-model does not immediately lead to good knowledge of the entire model. Often, the most attractive approach to model studies is to write the model as computer software and study datasets generated by that software.

    Methods for sensitivity analysis (SA) and uncertainty analysis (UA) cannot be expected to be exactly the same for all models. In this thesis, we want to determine suitable SA and UA methods for a road traffic emission model, methods that can also be applied to any other model of similar structure. We examine parts of a well-known emission model and suggest a powerful data-generating tool. By studying generated datasets, we can examine properties in the model, suggest SA and UA methods and discuss the properties of these methods. We also present some of the results of applying the methods to the generated datasets.

    List of papers
    1. A new program for fast emission calculations based on the COPERT III model
    Open this publication in new window or tab >>A new program for fast emission calculations based on the COPERT III model
    (English)Manuscript (Other academic)
    Abstract [en]

    Emissions from road traffic are hard to measure and therefore usually estimated in models. In this paper the construction of the widely used COPERT III model is examined, and the model is rewritten in mathematical notation. The original COPERT III software is easily handled but is not suitable as an emissiondata generating tool for fast calculations over a broad variety of driving conditions, which is required for sensitivity analysis. An alternative program has been developed to meet the desired properties of such a tool. The construction of the alternative program is discussed together with its new abilities and restrictions. Some differences between the results from the original COPERT III software and the alternative program are analyzed and discussed.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14295 (URN)
    Available from: 2007-02-13 Created: 2007-02-13 Last updated: 2012-12-17
    2. Basic sensitivity analysis methods: applied to the COPERT III road traffic emission model
    Open this publication in new window or tab >>Basic sensitivity analysis methods: applied to the COPERT III road traffic emission model
    (English)Manuscript (Other academic)
    Abstract [en]

    Many complex systems are simulated in models, and these models are hard to evaluate completely. For example, the sensitivity of the model output for different inputs is seldom analyzed. This paper provides an introduction to sensitivity analysis and proposes some basic sensitivity analysis methods. The results are important, for example, in choosing a sampling scheme. Themethods are applied to the COPERT III model, and the sensitivity results are compared and discussed. Certain theoretical results simplify the sensitivity analysis in a special case, and the paper ends by recommending a method.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14296 (URN)
    Available from: 2007-02-13 Created: 2007-02-13 Last updated: 2012-12-17
    3. Global sensitivity analysis methods using response surface descriptions: applied to the COPERT III road traffic emission model
    Open this publication in new window or tab >>Global sensitivity analysis methods using response surface descriptions: applied to the COPERT III road traffic emission model
    (English)Manuscript (Other academic)
    Abstract [en]

    Sensitivity analyses may be local or global, one at a time or all at a time, or classified in other ways. This paper examines some response surface methods for instant calculations of many sensitivities at the same time. The appropriateness of replacing the original model with a simpler response surface is discussed.The methods are also compared with one at a time methods. Sensitivity results are calculated by applying the methods to the COPERT III model. The conclusion is that a simple response surface method should be preferred.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14297 (URN)
    Available from: 2007-02-13 Created: 2007-02-13 Last updated: 2012-12-17
    4. Variance-based sensitivity analysis: with application to a road traffic emission model
    Open this publication in new window or tab >>Variance-based sensitivity analysis: with application to a road traffic emission model
    (English)Manuscript (Other academic)
    Abstract [en]

    This paper discusses sensitivity analysis based on methods that divide the total variation of a particular response into components associated with the explaining variables or factors. Two methods for estimating variance components in no-interaction multiway designs are discussed, and their dependence on balancein the sampling design is studied. The methods are applied to datasets generated from a road traffic emission model.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14298 (URN)
    Available from: 2007-02-13 Created: 2007-02-13 Last updated: 2012-12-17
    5. Uncertainty analysis with uncertain input distributions: applied to a road traffic emission model
    Open this publication in new window or tab >>Uncertainty analysis with uncertain input distributions: applied to a road traffic emission model
    (English)Manuscript (Other academic)
    Abstract [en]

    The output of a model or an experiment is often fairly uncertain because the underlying conditions have to some extent been guessed at or estimated. Such uncertainty is usually described by examining the distribution of the output given an input of known distribution. In this paper, we discuss why this approachmay not be suitable for some problems, and consider an alternate approach in cases in which we have only vague information concerning the distributions of the inputs, regardless as to whether these inputs are continm:ms or categorical. Our approach is well suited for a mean output that represents the weighted sum of the outputs of categories, if there is a large dataset with an uncertain input distribution. In this study, the method is applied to a road traffic emission scenario.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-14299 (URN)
    Available from: 2007-02-13 Created: 2007-02-13 Last updated: 2012-12-17
  • 10.
    Eriksson, Olle
    Linköping University, Department of Mathematics, Statistics. Linköping University, Faculty of Arts and Sciences.
    Uncertainty analysis with uncertain input distributions: applied to a road traffic emission modelManuscript (Other academic)
    Abstract [en]

    The output of a model or an experiment is often fairly uncertain because the underlying conditions have to some extent been guessed at or estimated. Such uncertainty is usually described by examining the distribution of the output given an input of known distribution. In this paper, we discuss why this approachmay not be suitable for some problems, and consider an alternate approach in cases in which we have only vague information concerning the distributions of the inputs, regardless as to whether these inputs are continm:ms or categorical. Our approach is well suited for a mean output that represents the weighted sum of the outputs of categories, if there is a large dataset with an uncertain input distribution. In this study, the method is applied to a road traffic emission scenario.

  • 11.
    Eriksson, Olle
    Linköping University, Department of Mathematics, Statistics. Linköping University, Faculty of Arts and Sciences.
    Variance-based sensitivity analysis: with application to a road traffic emission modelManuscript (Other academic)
    Abstract [en]

    This paper discusses sensitivity analysis based on methods that divide the total variation of a particular response into components associated with the explaining variables or factors. Two methods for estimating variance components in no-interaction multiway designs are discussed, and their dependence on balancein the sampling design is studied. The methods are applied to datasets generated from a road traffic emission model.

  • 12.
    Eriksson, Olle
    et al.
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Backlund, EO
    Lundberg, Peter
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Lindstam, H
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    A method for comparisons between in vitro, in vivo and post mortem appearance of tereotactic RF-lesions in the pig brain.2000Conference paper (Other academic)
  • 13.
    Kullman, Eric
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Frozanpor, Farshad
    Söder Sjukhuset, Stockholm.
    Söderlund, Claes
    Söder Sjukhuset, Stockholm.
    Linder, Stefan
    Söder Sjukhuset, Stockholm.
    Sandström, Per
    Linköping University, Department of Clinical and Experimental Medicine, Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Surgery in Östergötland.
    Lindhoff-Larsson, Anna
    Östergötlands Läns Landsting.
    Toth, Ervin
    University Hospital MAS .
    Lindell, Gert
    University Hospital MAS.
    Jonas, Eduard
    Danderyd Hospital.
    Freedman, Jacob
    Danderyd Hospital.
    Ljungman, Martin
    Central Hospital Västerås.
    Rudberg, Claes
    Central Hospital Västerås.
    Ohlin, Bo
    Blekinge Hospital.
    Zacharias, Rebecka
    St Goran Hospital.
    Leijonmarck, Carl-Eric
    St Goran Hospital.
    Teder, Kalev
    Östergötlands Läns Landsting.
    Ringman, Anders
    Östergötlands Läns Landsting.
    Persson, Gunnar
    Ryhov Hospital.
    Gözen, Mehmet
    Västervik Hospital.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Covered versus uncovered self-expandable nitinol stents in the palliative treatment of malignant distal biliary obstruction: results from a randomized, multicenter study2010In: GASTROINTESTINAL ENDOSCOPY, ISSN 0016-5107, Vol. 72, no 5, p. 915-923Article in journal (Refereed)
    Abstract [en]

    Background: Covered biliary metal stents have been developed to prevent tumor ingrowth. Previous comparative studies are limited and often include few patients. Objective: To compare differences in stent patency, patient survival, and complication rates between covered and uncovered nitinol stents in patients with malignant biliary obstruction. Design: Randomized, multicenter trial conducted between January 2006 and October 2008. Setting: Ten sites serving a total catchment area of approximately 2.8 million inhabitants. Patients: A total of 400 patients with unresectable distal malignant biliary obstruction. Interventions: ERCP with insertion of covered or uncovered metal stent. Follow-up conducted monthly for symptoms indicating stent obstruction. Main Outcome Measurements: Time to stent failure, survival time, and complication rate. Results: The patient survival times were 116 days (interquartile range 242 days) and 174 days (interquartile range 284 days) in the covered and uncovered stent groups, respectively (P = .320). The first quartile stent patency time was 154 days in the covered stent group and 199 days in the uncovered stent group (P = .326). There was no difference in the incidence of pancreatitis or cholecystitis between the 2 groups. Stent migration occurred in 6 patients (3%) in the covered group and in no patients in the uncovered group (P = .030). Limitations: Randomization was not blinded. Conclusions: There were no significant differences in stent patency time, patient survival time, or complication rates between covered and uncovered nitinol metal stents in the palliative treatment of malignant distal biliary obstruction. However, covered stents migrated significantly more often compared with uncovered stents, and tumor ingrowth was more frequent in uncovered stents.

  • 14.
    Redéen, Stefan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Surgery . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Ryberg, Anna
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Petersson, Fredrik
    Ryhov Hospital.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Nägga, Katarina
    Linköping University, Department of Neuroscience and Locomotion, Geriatrics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Geriatric Medicine.
    Borch, Kurt
    Linköping University, Department of Clinical and Experimental Medicine, Surgery . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Homocysteine Levels in Chronic Gastritis and Other Conditions: Relations to Incident Cardiovascular Disease and Dementia2010In: DIGESTIVE DISEASES AND SCIENCES, ISSN 0163-2116, Vol. 55, no 2, p. 351-358Article in journal (Refereed)
    Abstract [en]

    Background Homocysteine levels in circulation are determined by several factors and hyperhomocysteinemia is reportedly associated with cardiovascular diseases and dementia. The aim of this study is to determine the relation of chronic gastritis and other conditions to homocysteine levels and their relation to incident cardiovascular diseases and dementia. Methods An adult population-based cohort (N = 488) was screened for H. pylori infection, gastro-duodenitis ( endoscopic biopsies), disease history, and lifestyle factors. Blood samples were analyzed for pepsinogen I and II ( gastric function), vitamin B12, folate, homocysteine, and cystatin C ( renal function). The methylenetetrahydrofolate reductase C677T polymorphism reportedly associated with hyperhomocysteinemia was analyzed by pyrosequencing. Incident cardiovascular diseases and dementia were monitored during a median follow-up interval of 10 years. Results At baseline, there was a positive relation of S-homocysteine to male gender, age, S-cystatin C, methylenetetrahydrofolate reductase 677TT genotype and atrophic gastritis. During follow-up, cardiovascular diseases occurred in 101/438 and dementia in 25/488 participants, respectively. Logistic regression analysis ( adjusting for gender, age at baseline, follow-up interval, BMI, smoking, alcohol consumption, NSAID use, P-cholesterol, and P-triglycerides) showed an association of S-homocysteine higher than 14.5 mu mol/l to cardiovascular diseases (OR 2.05 [95% c.i. 1.14-3.70]), but not to dementia overall. Conclusions Gender, age, vitamin B12, folate, renal function, atrophic gastritis and the methylenetetrahydrofolate 677TT genotype were significant determinants of homocysteine levels, which were positively related to incident cardiovascular diseases.

  • 15.
    Samuelsson, Annika
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Microbiology. Östergötlands Läns Landsting, Centre for Health and Developmental Care, Vårdhygien.
    Isaksson, Barbro
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Microbiology. Östergötlands Läns Landsting, Centre for Health and Developmental Care, Vårdhygien.
    Chabok, Abbas
    Uppsala University, Sweden .
    Jonasson, Jon
    Linköping University, Department of Clinical and Experimental Medicine, Molecular and Immunological Pathology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Pathology and Clinical Genetics.
    Nilsson, Lennart E
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Hanberger, Håkan
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Infectious Diseases in Östergötland.
    Changes in the aerobic faecal flora of patients treated with antibiotics for acute intra-abdominal infection2012In: Scandinavian Journal of Infectious Diseases, ISSN 0036-5548, E-ISSN 1651-1980, Vol. 44, no 11, p. 820-827Article in journal (Refereed)
    Abstract [en]

    Background: An open observational study was performed to investigate changes in the rectal flora and antibiotic susceptibility among faecal bacteria in patients treated with antibiotics for acute intra-abdominal infection. Methods: One hundred and forty patients with acute intra-abdominal infection requiring antibiotic treatment and hospitalization were included. Eight surgical units from the southern part of Sweden participated, between January 2006 and November 2007. Antibiotic treatments were according to local guidelines. Rectal swabs were obtained on admission (sample 1) and 2-14 days after the end of antibiotic treatment (sample 2). Aerobic bacteria and yeasts were analysed. The material was divided into 2 groups: 1 group with Enterobacteriaceae and 1 group with non-fermentative Gram-negative bacteria. The susceptibility to antibiotics in each group was compared between samples 1 and 2. Results: The main finding of this study on patients with severe intra-abdominal infections was a shift in the aerobic faecal flora following antibiotic treatment, from Escherichia coli to other more resistant Enterobacteriaceae, Enterococcus faecium, and yeasts. The susceptibility to cephalosporins and piperacillin-tazobactam decreased in Enterobacteriaceae. Conclusions: Following antibiotic treatment, a shift in the aerobic rectal flora to species with intrinsic antibiotic resistance was observed. This indicates that the emergence of resistance is not due to new mutations, but rather to selection of more resistant species. This should be taken into account when designing treatments for secondary intra-abdominal infections.

  • 16.
    Smeds, Staffan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Surgery . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Löfström, L
    Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Influence of nerve identification and the resection of nerves at risk on postoperative pain in open inguinal hernia repair2010In: HERNIA, ISSN 1265-4906, Vol. 14, no 3, p. 265-270Article in journal (Refereed)
    Abstract [en]

    Surgical strategy regarding nerve identification and resection in relation to chronic postoperative pain remains controversial. A central question is whether nerves in the operation field, when identified, should be preserved or resected. In the present study, the hypotheses that the identification and consequent resection of nerves at risk have no influence on postoperative pain has been tested. A single-centre study was conducted in 525 patients undergoing Lichtenstein hernioplasty. One surgeon (364 operations, Group A) consequently resected nerves at risk for being injured and nine surgeons (161 operations, Group B) adhered to the general routine of nerve preservation. All cases were ambulatory surgery on anaesthetised patients and the groups were similar with regard to age, body mass index (BMI) and preoperative pain. Self-reported pain at 3 months was recorded on a 10-box visual analogue scale (VAS). The identification and resection of nerves were continuously registered. Statistical calculations were performed with Fishers exact test and ordinal logistic regression. There was no significant difference in the number of identified nerves in the two groups of patients (iliohypogastricus, P = 0.555; ilioinguinalis, P = 0.831; genital branch, P = 0.214). However, the number of resected nerves was significantly higher in Group A for the iliohypogastric nerve, P andlt; 0.001, but not for ilioinguinalis, P = 0.064, and genital branch, P = 0.362. Non-identification of the ilioinguinal nerve correlated to the highest level of self-reported postoperative pain at 3 months. Patients in Group A, who had nerves at risk resected from the operation field, reported significantly less postoperative pain at 3 months, P = 0.007. This register study confirms the importance of nerve identification. Nerve resection strategy with the consequent removal of nerves at risk gives a significantly better outcome in Lichtenstein hernioplasty.

  • 17.
    Stening, Kent
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Berg, Göran
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Hammar, Mats
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Voster, Helene
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Amandusson, Åsa
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Influence of estrogen levels on thermal perception, pain thresholds and pain tolerance: Studies on women undergoing in vitro fertilization2012In: Journal of Pain, ISSN 1526-5900, E-ISSN 1528-8447, Vol. 13, no 5, p. 459-466Article in journal (Refereed)
    Abstract [en]

    We examined the relationship between estrogen and pain in women undergoing in vitro fertilization (IVF). Quantitative sensory tests (QST) were performed twice during the IVF-regimen: once during hormonal down-regulation and once during hormonal upregulation. A group of healthy men and a group of women using monophasic contraceptives were also examined, to control for session-to-session effects. Among the women undergoing IVF, serum 17β-estradiol levels differed strongly between treatments as expected, and increased from 65.7 (SD = 26) pmol/l during the downregulation phase, to 5188 (SD = 2524) pmol/l during the up-regulation phase. Significant outcomes in the QST were only seen for temperature perception thresholds (1.7°C vs. 2.2°C; P = 0.003) and cold pain threshold (11.5°C vs. 14.5°C; P = 0.04). A similar change in cold pain threshold was also seen in the two control groups, however, and statistical analysis suggested that this change was due to a session-to-session effect rather than being the result of hormonal modulation. Heat pain thresholds, heat tolerance, pressure pain thresholds, and the cold pressor test showed no significant differences between sessions. These data demonstrate that pain perception and pain thresholds in healthy women show little, if any, changes even with major variations in serum estradiol levels.

  • 18.
    Stening, Kent
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Hammar, Mats
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Berg, Göran
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Pain thresholds and pain tolerance during the ovulatory cycle in healthy women: quantitative sensory testingManuscript (preprint) (Other academic)
    Abstract [en]

    Hormonal influence on pain sensitivity at different menstrual phases is a field of contradictory results. One reason is methodological differences between studies and methodological limitations such as lack of confirmation of cycle phase by measurement of actual hormone levels. In the present study, 14 healthy women were followed during three menstrual cycles and were subjected to a battery of quantitative sensory tests 1-4 after start of menses (follicular phase) and 2-11 days before next menses (luteal phase). The material was analyzed in three different ways: cycle phase determined according to the calendar method; cycle phase determined by hormone values, with cycles showing hormone values outside reference values omitted; and cycles subdivided into three subgroups depending on hormone profile (“normal” cycle; high s-estrogen during the assumed luteal phase; and low progesterone during the assumed luteal phase). However, neither analysis showed any significant differences between the measurement done during immediate after onset of menses and those performed in the period before next menses. Consistent with the results of several previous studies, the findings indicate that pain sensitivity does not seem to vary as a function of the menstrual cycle.

  • 19.
    Stening, Kent
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Henriksson, Karl-Gösta
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Brynhildsen, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Lindh-Åstrand, Lotta
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Berg, Göran
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Hammar, Mats
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Amandusson, Åsa
    Uppsala University.
    Blomqvist, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Hormonal replacement therapy does not affect self-estimated pain or experimental pain responses in post-menopausal women suffering from fibromyalgia: a double-blind, randomized, placebo-controlled trial2011In: RHEUMATOLOGY, ISSN 1462-0324, Vol. 50, no 3, p. 544-551Article in journal (Refereed)
    Abstract [en]

    Methods. Twenty-nine post-menopausal women were randomized to either 8 weeks of treatment with transdermal 17 beta-oestradiol (50 mu g/day) or placebo according to a double-blind protocol. A self-estimation of pain, a set of quantitative sensory tests measuring thresholds to temperature, thermal pain, cold pain and pressure pain, and a cold pressor test were performed on three occasions: before treatment, after 8 weeks of treatment and 20 weeks after cessation of treatment. Results. Hormonal replacement treatment significantly increased serum oestradiol levels as expected (P andlt; 0.01). However, no differences in self-estimated pain were seen between treatment and placebo groups, nor were there any differences between the two groups regarding the results of the quantitative sensory tests or the cold pressor test at any of the examined time points. Conclusion. Eight weeks of transdermal oestradiol treatment does not influence perceived pain, pain thresholds or pain tolerance as compared with placebo treatment in post-menopausal women suffering from FM.

  • 20.
    Stening, Kent
    et al.
    Linköping University, Department of Biomedicine and Surgery. Linköping University, Faculty of Health Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Wahren, Lis Karin
    Linköping University, Department of Social and Welfare Studies. Linköping University, Faculty of Health Sciences.
    Berg, Göran
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Obstetrics and gynecology. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Hammar, Mats
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Obstetrics and gynecology. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Blomqvist, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Pain sensations to the cold pressor test in normally menstruating women: Comparison with men and relation to menstrual phase and serum sex steroid levels2007In: American Journal of Physiology. Regulatory Integrative and Comparative Physiology, ISSN 0363-6119, E-ISSN 1522-1490, Vol. 293, no 4Article in journal (Refereed)
    Abstract [en]

    The role of gonadal hormones on pain sensations was investigated in normally menstruating women (n = 16) using the cold pressor test. Tolerance time, pain threshold, and pain intensity were examined once a week during a 4-wk period, and serum concentrations of 17β-estradiol and progesterone were determined at each test session, which were classified into the early follicular phase, late follicular phase, early luteal phase, and late luteal phase, as determined by the first day of menses and the actual hormone levels recorded. A group of men (n = 10) of the same age interval was examined for comparison. The data show that pain threshold was reduced during the late luteal phase compared with the late follicular phase, and hormone analyses showed significant positive correlation between the progesterone concentration and lowered pain threshold and increasing pain intensity. Hormone analysis also showed an interaction between S-estradiol and S-progesterone on pain intensity, demonstrating that the increased perceived pain intensity that was associated with high progesterone concentrations was significantly reduced with increasing levels of estradiol. While no statistically significant sex differences in pain measurements were found, women displayed much more pronounced, and statistically significant, session-to-session effects than men, with increased pain threshold and decreased pain intensity with each test session. Hence, these data suggest that the changes in the serum concentration of gonadal hormones that occur during the menstrual cycle influence pain sensations elicited by noxious tonic cold stimulation and show that adaptation to the cold pressor test may be sex dependent. © 2007 the American Physiological Society.

  • 21.
    Timpka, Toomas
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Preventive and Social Medicine and Public Health Science. Linköping University, Faculty of Health Sciences.
    Eriksson, Henrik
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Gursky, Elin A
    ANSER Analyt Serv Inc.
    Stromgren, Magnus
    Umea University.
    Holm, Einar
    Umea University.
    Ekberg, Joakim
    Linköping University, Department of Medical and Health Sciences, Division of Preventive and Social Medicine and Public Health Science. Linköping University, Faculty of Health Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Grimvall, Anders
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Valter, Lars
    Östergötlands Läns Landsting, Centre for Health and Developmental Care, Centre for Public Health.
    Nyce, James M
    Ball State University.
    Requirements and Design of the PROSPER Protocol for Implementation of Information Infrastructures Supporting Pandemic Response: A Nominal Group Study2011In: PLOS ONE, ISSN 1932-6203, Vol. 6, no 3, p. 0017941-Article in journal (Refereed)
    Abstract [en]

    Background: Advanced technical systems and analytic methods promise to provide policy makers with information to help them recognize the consequences of alternative courses of action during pandemics. Evaluations still show that response programs are insufficiently supported by information systems. This paper sets out to derive a protocol for implementation of integrated information infrastructures supporting regional and local pandemic response programs at the stage(s) when the outbreak no longer can be contained at its source. Methods: Nominal group methods for reaching consensus on complex problems were used to transform requirements data obtained from international experts into an implementation protocol. The analysis was performed in a cyclical process in which the experts first individually provided input to working documents and then discussed them in conferences calls. Argument-based representation in design patterns was used to define the protocol at technical, system, and pandemic evidence levels. Results: The Protocol for a Standardized information infrastructure for Pandemic and Emerging infectious disease Response (PROSPER) outlines the implementation of information infrastructure aligned with pandemic response programs. The protocol covers analyses of the community at risk, the response processes, and response impacts. For each of these, the protocol outlines the implementation of a supporting information infrastructure in hierarchical patterns ranging from technical components and system functions to pandemic evidence production. Conclusions: The PROSPER protocol provides guidelines for implementation of an information infrastructure for pandemic response programs both in settings where sophisticated health information systems already are used and in developing communities where there is limited access to financial and technical resources. The protocol is based on a generic health service model and its functions are adjusted for community-level analyses of outbreak detection and progress, and response program effectiveness. Scientifically grounded reporting principles need to be established for interpretation of information derived from outbreak detection algorithms and predictive modeling.

  • 22.
    Timpka, Toomas
    et al.
    Linköping University, Department of Medical and Health Sciences, Social Medicine and Public Health Science. Linköping University, Faculty of Health Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Spreco, Armin
    Linköping University, Department of Medical and Health Sciences, Social Medicine and Public Health Science. Linköping University, Faculty of Health Sciences.
    Gursky, Elin A
    National Strategies Support Directorate, ANSER/Analytic Services Inc, Arlington, Virginia, USA.
    Strömgren, Magnus
    Umeå University.
    Holm, Einar
    Umeå University.
    Ekberg, Joakim
    Linköping University, Department of Medical and Health Sciences, Social Medicine and Public Health Science. Linköping University, Faculty of Health Sciences.
    Dahlström, Örjan
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Valter, Lars
    Östergötlands Läns Landsting, Center for Health and Developmental Care, Center for Public Health.
    Eriksson, Henrik
    Linköping University, Department of Computer and Information Science, MDALAB - Human Computer Interfaces. Linköping University, The Institute of Technology.
    Age as a determinant for dissemination of seasonal and pandemic influenza: an open cohort study of influenza outbreaks in Östergötland County, Sweden2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 2, p. e31746-Article in journal (Refereed)
    Abstract [en]

    An understanding of the occurrence and comparative timing of influenza infections in different age groups is important for developing community response and disease control measures. This study uses data from a Scandinavian county (population 427.000) to investigate whether age was a determinant for being diagnosed with influenza 2005-2010 and to examine if age was associated with case timing during outbreaks. Aggregated demographic data were collected from Statistics Sweden, while influenza case data were collected from a county-wide electronic health record system. A logistic regression analysis was used to explore whether case risk was associated with age and outbreak. An analysis of variance was used to explore whether day for diagnosis was also associated to age and outbreak. The clinical case data were validated against case data from microbiological laboratories during one control year. The proportion of cases from the age groups 10-19 (p<0.001) and 20-29 years old (p<0.01) were found to be larger during the A pH1N1 outbreak in 2009 than during the seasonal outbreaks. An interaction between age and outbreak was observed (p<0.001) indicating a difference in age effects between circulating virus types; this interaction persisted for seasonal outbreaks only (p<0.001). The outbreaks also differed regarding when the age groups received their diagnosis (p<0.001). A post-hoc analysis showed a tendency for the young age groups, in particular the group 10-19 year olds, led outbreaks with influenza type A H1 circulating, while A H3N2 outbreaks displayed little variations in timing. The validation analysis showed a strong correlation (r = 0.625;p<0.001) between the recorded numbers of clinically and microbiologically defined influenza cases. Our findings demonstrate the complexity of age effects underlying the emergence of local influenza outbreaks. Disentangling these effects on the causal pathways will require an integrated information infrastructure for data collection and repeated studies of well-defined communities.

  • 23.
    Timpka, Toomas
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Preventive and Social Medicine and Public Health Science. Linköping University, Faculty of Health Sciences.
    Gursky, Elin A
    ANSER/Analytic Services Inc, Arlington, Virginia, USA.
    Spreco, Armin
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Dahlström, Örjan
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Strömgren, Magnus
    Umeå University, Sweden.
    Holm, Einar
    Umeå University, Sweden.
    Ekberg, Joakim
    Linköping University, Department of Medical and Health Sciences, Division of Preventive and Social Medicine and Public Health Science. Linköping University, Faculty of Health Sciences.
    Hinkula, Jorma
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Nyce, Jim M
    Ball State University, Muncie, IN, USA..
    Eriksson, Henrik
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Predictive value of telenursing complaints in influenza surveillance: a prospective cohort study in Sweden2013Conference paper (Other academic)
  • 24.
    Timpka, Toomas
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Health and Developmental Care, Center for Public Health.
    Spreco, Armin
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Dahlström, Örjan
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, The Swedish Institute for Disability Research.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Gursky, Elin
    National Strategies Support Directorate, ANSER/Analytic Services Inc., Arlington, VA, USA.
    Ekberg, Joakim
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Blomqvist, Eva
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Strömgren, Magnus
    Department of Geography and Economic History, Umeå University, Sweden.
    Karlsson, David
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Eriksson, Henrik
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Nyce, James
    Department of Anthropology, Ball State University, Muncie, IN, USA.
    Hinkula, Jorma
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Holm, Einar
    Department of Geography and Economic History, Umeå University, Sweden.
    Performance of eHealth data sources in local influenza surveillance: a 5-year open cohort study2014In: Journal of Medical Internet Research, ISSN 1438-8871, E-ISSN 1438-8871, Vol. 16, no 4, p. e116-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: There is abundant global interest in using syndromic data from population-wide health information systems--referred to as eHealth resources--to improve infectious disease surveillance. Recently, the necessity for these systems to achieve two potentially conflicting requirements has been emphasized. First, they must be evidence-based; second, they must be adjusted for the diversity of populations, lifestyles, and environments.

    OBJECTIVE: The primary objective was to examine correlations between data from Google Flu Trends (GFT), computer-supported telenursing centers, health service websites, and influenza case rates during seasonal and pandemic influenza outbreaks. The secondary objective was to investigate associations between eHealth data, media coverage, and the interaction between circulating influenza strain(s) and the age-related population immunity.

    METHODS: An open cohort design was used for a five-year study in a Swedish county (population 427,000). Syndromic eHealth data were collected from GFT, telenursing call centers, and local health service website visits at page level. Data on mass media coverage of influenza was collected from the major regional newspaper. The performance of eHealth data in surveillance was measured by correlation effect size and time lag to clinically diagnosed influenza cases.

    RESULTS: Local media coverage data and influenza case rates showed correlations with large effect sizes only for the influenza A (A) pH1N1 outbreak in 2009 (r=.74, 95% CI .42-.90; P<.001) and the severe seasonal A H3N2 outbreak in 2011-2012 (r=.79, 95% CI .42-.93; P=.001), with media coverage preceding case rates with one week. Correlations between GFT and influenza case data showed large effect sizes for all outbreaks, the largest being the seasonal A H3N2 outbreak in 2008-2009 (r=.96, 95% CI .88-.99; P<.001). The preceding time lag decreased from two weeks during the first outbreaks to one week from the 2009 A pH1N1 pandemic. Telenursing data and influenza case data showed correlations with large effect sizes for all outbreaks after the seasonal B and A H1 outbreak in 2007-2008, with a time lag decreasing from two weeks for the seasonal A H3N2 outbreak in 2008-2009 (r=.95, 95% CI .82-.98; P<.001) to none for the A p H1N1 outbreak in 2009 (r=.84, 95% CI .62-.94; P<.001). Large effect sizes were also observed between website visits and influenza case data.

    CONCLUSIONS: Correlations between the eHealth data and influenza case rates in a Swedish county showed large effect sizes throughout a five-year period, while the time lag between signals in eHealth data and influenza rates changed. Further research is needed on analytic methods for adjusting eHealth surveillance systems to shifts in media coverage and to variations in age-group related immunity between virus strains. The results can be used to inform the development of alert-generating eHealth surveillance systems that can be subject for prospective evaluations in routine public health practice.

  • 25.
    Timpka, Toomas
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Health and Developmental Care, Center for Public Health.
    Spreco, Armin
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Health and Developmental Care, Center for Public Health.
    Dahlström, Örjan
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Gursky, Elin
    ANSER/Analytic Services Inc, Arlington, Virginia, USA.
    Ekberg, Joakim
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Blomqvist, Eva
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Arts and Sciences.
    Strömgren, Magnus
    Umeå University, Sweden.
    Karlsson, David
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Eriksson, Henrik
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Nyce, Jim
    Ball State University, Muncie, IN, USA.
    Hinkula, Jorma
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Holm, Einar
    Umeå University, Sweden.
    Predictive value of telenursing complaints in influenza surveillance: a prospective cohort study in Sweden2013Conference paper (Other academic)
  • 26.
    Timpka, Toomas
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Health and Developmental Care, Center for Public Health.
    Spreco, Armin
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Dahlström, Örjan
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Gursky, Elin
    ANSER/Analytic Services Inc, Arlington, Virginia, USA.
    Ekberg, Joakim
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Strömgren, Magnus
    Umeå University, Sweden.
    Karlsson, David
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Hinkula, Jorma
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Holm, Einar
    Umeå University, Sweden.
    Intentions to perform non-pharmaceutical protective behaviors during influenza outbreaks: a cross-sectional study of a representative sample of the Swedish adult population2013Conference paper (Other academic)
  • 27.
    Timpka, Toomas
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Health and Developmental Care, Center for Public Health.
    Spreco, Armin
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Dahlström, Örjan
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, The Swedish Institute for Disability Research.
    Gursky, E. A.
    Analytic Serv Inc, VA USA.
    Stromgren, M.
    Umeå University, Sweden.
    Holm, E.
    Umeå University, Sweden.
    Ekberg, Joakim
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Hinkula, Jorma
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Nyce, J. M.
    Ball State University, IN 47306 USA.
    Eriksson, Henrik
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Predictive performance of telenursing complaints in influenza surveillance: a prospective cohort study in Sweden2014In: Eurosurveillance, ISSN 1025-496X, E-ISSN 1560-7917, Vol. 19, no 46, p. 24-32Article in journal (Refereed)
    Abstract [en]

    Syndromic data sources have been sought to improve the timely detection of increased influenza transmission. This study set out to examine the prospective performance of telenursing chief complaints in predicting influenza activity. Data from two influenza seasons (2007/08 and 2008/09) were collected in a Swedish county (population 427,000) to retrospectively determine which grouping of telenursing chief complaints had the largest correlation with influenza case rates. This grouping was prospectively evaluated in the three subsequent seasons. The best performing telenursing complaint grouping in the retrospective algorithm calibration was fever (child, adult) and syncope (r=0.66; pless than0.001). In the prospective evaluation, the performance of 14-day predictions was acceptable for the part of the evaluation period including the 2009 influenza pandemic (area under the curve (AUC)=0.84; positive predictive value (PPV)=0.58), while it was strong (AUC=0.89; PPV=0.93) for the remaining evaluation period including only influenza winter seasons. We recommend the use of telenursing complaints for predicting winter influenza seasons. The method requires adjustments when used during pandemics.

  • 28.
    Timpka, Toomas
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Health and Developmental Care, Center for Public Health.
    Spreco, Armin
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Health and Developmental Care, Center for Public Health.
    Gursky, Elin
    National Strategies Support Directorate, ANSER/Analytic Services Inc, Arlington, Virginia, USA.
    Eriksson, Olle
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Dahlström, Örjan
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Strömgren, Magnus
    Umeå University, Sweden.
    Ekberg, Joakim
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Health and Developmental Care, Center for Public Health.
    Pilemalm, Sofie
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Karlsson, David
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, The Institute of Technology.
    Hinkula, Jorma
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine.
    Holm, Einar
    Umeå University, Sweden.
    Intentions to perform non-pharmaceutical protective behaviors during influenza outbreaks in Sweden: a cross-sectional study following a mass vaccination campaign2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 3, p. e91060-Article in journal (Refereed)
    Abstract [en]

    Failure to incorporate the beliefs and attitudes of the public into theoretical models of preparedness has been identified as a weakness in strategies to mitigate infectious disease outbreaks. We administered a cross-sectional telephone survey to a representative sample (n = 443) of the Swedish adult population to examine whether self-reported intentions to improve personal hygiene and increase social distancing during influenza outbreaks could be explained by trust in official information, self-reported health (SF-8), sociodemographic factors, and determinants postulated in protection motivation theory, namely threat appraisal and coping appraisal. The interviewees were asked to make their appraisals for two scenarios: a) an influenza with low case fatality and mild lifestyle impact; b) severe influenza with high case fatality and serious disturbances of societal functions. Every second respondent (50.0%) reported high trust in official information about influenza. The proportion that reported intentions to take deliberate actions to improve personal hygiene during outbreaks ranged between 45–85%, while less than 25% said that they intended to increase social distancing. Multiple logistic regression models with coping appraisal as the explanatory factor most frequently contributing to the explanation of the variance in intentions showed strong discriminatory performance for staying home while not ill (mild outbreaks: Area under the curve [AUC] 0.85 (95% confidence interval 0.82;0.89), severe outbreaks AUC 0.82 (95% CI 0.77;0.85)) and acceptable performance with regard to avoiding public transportation (AUC 0.78 (0.74;0.82), AUC 0.77 (0.72;0.82)), using handwash products (AUC 0.70 (0.65;0.75), AUC 0.76 (0.71;0.80)), and frequently washing hands (AUC 0.71 (0.66;0.76), AUC 0.75 (0.71;0.80)). We conclude that coping appraisal was the explanatory factor most frequently included in statistical models explaining self-reported intentions to carry out non-pharmaceutical health actions in the Swedish outlined context, and that variations in threat appraisal played a smaller role in these models despite scientific uncertainties surrounding a recent mass vaccination campaign.

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