| 1. |
- Fhärm, Eva, 1955-
(author)
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Treatment of cardiovascular risk factors in type 2 diabetes : time trends and clinical practice
- 2010
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Doctoral thesis (other academic/artistic)abstract
- Objectives Patients with type 2 diabetes are at much greater risk of developing cardiovascular diseases (CVD), including coronary heart disease (CHD), compared to non-diabetics. The lowering of glucose, blood pressure, and plasma lipid levels has been shown to reduce CHD risk, and treatment goals for these risk factors are now part of clinical practice guidelines. However, the incidence and outcome of CHD in diabetic patients does not show the same favourable trend as in the general population. Thus, the overall aim of the thesis was to investigate how the treatment goals for CVD risk factors contained in the national guidelines for diabetes care were reflected in clinical practice, and to explore factors that might influence the remaining high incidence of CHD in the type 2 diabetes population. Research designs and results I. The effectiveness of the introduction of treatment goals for dyslipidaemia was evaluated in a retrospective observational population-based cross-sectional study of 971 diabetic patients participating in the Västerbotten Intervention Programme (VIP) 1995–2004. There was a stronger trend of decrease in cholesterol levels among patients with diabetes compared to the non-diabetic population in 2000–2004. Increased use of lipid-lowering agents influenced the trend in diabetic patients, even though only 25.3% received lipid-lowering treatment after the introduction of the new guidelines. II. The experiences of general practitioners relating to treatment practice for type 2 diabetes with specific focus on the prevention of cardiovascular disease were explored in a focus group study. The overall theme was ‘dilemmas’ in GPs’ treatment practice for patients with type 2 diabetes. Five main dilemma categories were identified. First, GPs were hesitant about labelling a person who feels healthy as ill. Second, as regards communicating a diabetes diagnosis and its consequences, GPs were unsure as to whether patients should be frightened or comforted. Third, GPs experienced uncertainty in their role: should they take responsibility for the care or not? Fourth, GPs expressed concern over a conflict between lifestyle changes and drug treatment. Fifth, the GPs described difficulties when attempting to translate science into reality. III. Screening for microvascular and coronary heart disease according to national guidelines was evaluated in a cross-sectional study of 201 screening-detected patients with type 2 diabetes 1.5±0.7 years after diagnosis. A larger proportion of diabetic patients was screened for nephropathy and retinopathy than for CHD. Twenty-three percent of the patients had minor or major ECG abnormalities, but ECG findings seemed to have little or no impact on CHD prevention using lipid-lowering medication and ASA. A clinical history of CHD correlated with a larger proportion of patients receiving secondary prevention. IV. Time trends relating to the achievement of treatment goals and 10-year CHD risk at three years of diabetes duration were studied in 19,382 patients with type 2 diabetes without CHD, who were reported by primary health care sources in the National Diabetes Register in 2003–2008. National treatment goals for glycaemia, blood pressure, total cholesterol, and LDL cholesterol were achieved in 78.4%, 65.5%, 55.6%, and 61.0%, respectively, of the diabetic patients in 2008 following a trend of improved results in 2003–2008. Absolute 10-year risk of CHD increased between year of diagnosis and follow up in a studied subgroup while modifiable risk decreased. Conclusions The introduction of treatment goals for dyslipidemia in Swedish national guidelines in 1999 were reflected in lowered cholesterol levels in people with type 2 diabetes. Since the introduction of the guidelines, an increasing number of diabetic patients are treated in accordance with guidelines. A remaining microvascular focus on the patients together with the revealed dilemmas within the GP’s consultation with diabetic patients might negatively influence the remaining high incidence of CHD in the type 2 diabetes population. Lipid levels, blood pressure and smoking are targets for further improvements.
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| 2. |
- Johansson, Cecilia, 1988-
(author)
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Risk markers and incidence of atrial fibrillation in northern Sweden
- 2023
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Doctoral thesis (other academic/artistic)abstract
- Background: Atrial fibrillation (AF) is the most common clinically significant arrythmia with a prevalence of approximately 3% in the general population. Less is known about the incidence of AF. In order to reduce the incidence of AF, it is of essence to identify modifiable risk factors for the disease.Aims: The aims of this thesis were (1) to estimate the incidence of AF and to assess the prevalence of provoking factors and risk factors for stroke and systemic embolism at the time of AF diagnosis, (2) to study the association between alcohol consumption and risk of AF, (3) to study the association between weight, height, weight change, and risk of AF, and (4) to study the association between normal or high normal blood pressure (BP), compared to optimal BP, and risk of AF.Methods: To determine the incidence of AF and the prevalence of provoking factors and risk factors for stroke and systemic embolism at AF diagnosis, an observational study was performed between January 1, 2011, and December 31, 2012, in the municipalities of Skellefteå and Norsjö, Västerbotten, Sweden. Diagnosis registries were searched for cases of incident AF. All AF diagnoses were verified by electrocardiogram. Data regarding provoking factors, type of AF and presence of risk factors for stroke and systemic embolism (as assessed by the CHA2DS2-VASc score) was obtained from medical records. Incidence was calculated by dividing the number of incident AF cases by the time at risk for the population.The association between alcohol consumption, weight, height, weight change, normal BP, high normal BP, and risk of AF was investigated in a population-based cohort study of participants of the Västerbotten Intervention Programme (VIP). Residents of Västerbotten County aged 30, 40, 50 and 60 years who had participated in the VIP health examinations between January 1, 1988, and September 5, 2014, were included. Individuals who had been diagnosed with AF before participating in the VIP were excluded. Study participants were followed until a diagnosis of AF, death, migration from the study area, or the end of the study on September 5, 2014. Incident AF cases were identified using the Swedish National Patient Registry. The health examinations included measurements of height and weight, systolic BP, diastolic BP, fasting glucose, oral glucose tolerance, and cholesterol. Participants also answered a questionnaire addressing any history of diabetes and myocardial infarction, alcohol use, education level, smoking habits, medications, and physical activity. Optimal BP was defined as BP < 120/80 mm Hg. Normal BP was defined as BP 120–129/80–84 mm Hg. High normal BP was defined as BP 130–139/85–89 mm Hg. Hypertension was defined as BP ≥ 140/90 mm Hg. Cox proportional hazards regression analysis was used to assess the associations between alcohol consumption, weight, height, weight change, normal BP, high normal BP, and risk of AF. These were performed with crude, age-adjusted, and multivariable models adjusted for other cardiovascular risk factors (age, sex, body mass index, hypertension, cholesterol, previous myocardial infarction, diabetes, problem drinking, smoking, education level, and leisure-time physical activity).Results: The incidence of AF was 4.0 cases of AF per 1000 person-years. In approximately one fifth of participants, a provoking factor was present at the first episode of AF. The CHA2DS2-VASc score was 2 or higher in 81% of participants. Permanent AF was the most common type of AF and was seen in about one third of the participants.When studying the association between alcohol consumption and risk of AF, 109,230 health examination participants were included in the study cohort and were followed for 1,484,547 person-years. During the study period, 5230 participants developed incident AF. Men with alcohol consumption in the highest quartile (≥ 4.83 standard drinks weekly) had a hazard ratio (HR) of 1.21 (95% confidence interval [CI] 1.09-1.34) for AF in a multivariable model when compared to men with an alcohol consumption in the lowest quartile (< 0.90 standard drinks weekly). In men, problem drinking was also associated with an increased risk of AF (HR 1.24, 95% CI 1.10–1.39 in a multivariable model). Among women, no significant association between alcohol consumption, problem drinking, and risk of AF was identified.In a fully adjusted model, height, weight, body mass index, and body surface area were positively associated with risk of incident AF. Among participants who underwent two health examinations 10 years apart, 1142 persons developed AF. The mean weight change from baseline was a weight gain of 4.8%. There was no significant association between either weight gain or weight loss and risk of AF.In the study of the association between normal BP, high normal BP, and risk of AF, 109,697 persons with a total of 162,982 health examinations were included. Incident AF was diagnosed in 5260 participants. There was an increased risk of incident AF in persons with normal BP (HR 1.11, 95% CI 1.01–1.27) and in persons with high normal BP (HR 1.23, 95% CI 1.10–1.38) compared to optimal BP in a multivariable model. Systolic BP and diastolic BP were associated with risk of incident AF, with HRs of 1.11 (95% CI 1.10–1.13) and 1.13 (95% CI 1.09–1.16) per 10 mmHg, respectively, in multivariable models. A restricted cubic spline analysis indicated a gradually increasing risk of AF with increasing systolic BP and diastolic BP.Conclusions: AF has an incidence of 4.0 per 1000 person-years. Alcohol consumption and problem drinking were associated with higher risk of AF in men, but not in women. Weight, height, body mass index, and body surface area were associated with increased risk of incident AF. Normal BP and high normal BP, when compared to optimal BP, were associated with increased risk of incident AF.
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| 3. |
- Johansson, Magdalena, 1984-
(author)
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Epidemiology of venous thromboembolism with focus on risk markers
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Background: Venous thromboembolism (VTE) is a vascular disease with an incidence of approximately 140 cases per 100,000 person-years in adults. The incidence of VTE has increased over the last decades, and more than 20% of affected individuals die in the first year after diagnosis. To reduce the incidence of VTE, it is important to identify modifiable risk factors for the condition.Aims: The aims of this thesis were a) To study the incidence of first-time VTE and the prevalence of risk markers for VTE at the time of VTE diagnosis, b) To determine the validity of diagnoses of deep vein thrombosis and pulmonary embolism in administrative registries, and c) To study the association between glucose levels, diabetes, alcohol consumption, physical activity and risk of first-time VTE.Methods: To determine the incidence of first-time VTE and the prevalence of risk markers for VTE at the time of VTE diagnosis, a retrospective, population-based cohort study was conducted. The study included all adult residents of Västerbotten County during the year 2006. All other aims were addressed in the prospective, population-based Venous thromboEmbolism In Northern Sweden (VEINS) cohort study. The VEINS cohort included 108,025 residents of Västerbotten County aged 30 to 60 years without previous VTE events. They were included from 1985 onwards and were followed until a VTE event, death, emigration, or the study end on September 5, 2014. All underwent a health examination within the Västerbotten Intervention Programme where weight, height, blood pressure and glucose levels were measured, and answered a questionnaire regarding smoking, education level, medication use, history of diabetes, alcohol intake and physical activity. VTE diagnoses were validated by review of medical records and radiology reports. To study the validity of diagnoses of deep vein thrombosis and pulmonary embolism in administrative registries, a registry search for International Classification of Diseases diagnosis codes indicating pulmonary embolism and/or deep vein thrombosis events was made in the Swedish National Patient Registry and the Cause of Death Registry. An additional search using an extended set of International Classification of Diseases diagnosis codes was performed in order to identify misclassified events.Results: The incidence of first-time VTE was 137 (95% confidence interval [CI] 122–154) per 100,000 adults per year. The most common risk markers for VTE were recent hospitalization and concurrent malignancy. The positive predictive value for a diagnosis of pulmonary embolism was 80.7% (95% CI 78.4–82.9), and that of deep vein thrombosis 59.2% (95% CI 56.7–61.7). Misclassification occurred in 1.1% (95% CI 0.4–1.7) of pulmonary embolism events and in 16.4% (95% CI 14.2–18.7) of deep vein thrombosis events. In the VEINS cohort, a total of 2,054 participants experienced an objectively verified first-time VTE event during approximately 1.5 million person-years of follow-up. In univariable analysis, there were associations between fasting plasma glucose, oral glucose tolerance test two-hour post-load plasma glucose, diabetes and increased risk of first-time VTE. These associations were attenuated after adjustment for potential confounders, and were no longer significant. There was an association between alcohol consumption and risk of first-time VTE in men (P for trend 0.02 after adjustments for increased risk of first-time VTE over quartiles of weekly alcohol consumption). Alcohol dependence was associated with risk of first-time VTE in men (hazard ratio [HR] 1.30; 95% CI 1.07–1.59 after adjustments). In women, there were no significant associations between alcohol consumption and risk of first-time VTE. Women who performed leisure time physical activity at least once a week had a lower risk of first-time VTE (HR 0.83; 95% CI 0.71–0.98 after adjustments) compared to women with less or no physical activity. Women with high occupational physical activity also had a lower risk of first-time VTE (HR 0.85; 95% CI 0.74–0.98 after adjustments). In men, there were no consistent association between either measure of physical activity and risk of first-time VTE. Conclusions: VTE is a common vascular disease. Registry data on diagnoses of pulmonary embolism, but not deep vein thrombosis, is of acceptable quality and can be considered for use in registry-based studies. Glucose levels and diabetes are not associated with risk of first-time VTE. Alcohol intake and alcohol dependence are associated with an increased risk of first-time VTE in men, whereas high leisure time physical activity and occupational physical activity are associated with a decreased risk of first-time VTE in women.
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| 4. |
- Andersson K, Pernille
(author)
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Changing the servicescape : The influence of music, self-disclosure and eye gaze on service encounter experience and approach-avoidance behavior
- 2016
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Doctoral thesis (other academic/artistic)abstract
- The purpose of this thesis is to investigate and understand the effect of a servicescape’s ambient and social conditions on consumers’ service encounter experience and their approach/avoidance behavior in a retail context. In three papers, with a total sample of over 1600 participants (including 550 actual consumers) and seven experiments, the author investigates the effect of music (ambient stimuli), employees’ self-disclosure (verbal social stimuli) and employees’ gazing behavior (nonverbal social stimuli) on consumers’ service encounter experience and approach/avoidance behavior in a retail store.Paper I comprised two experiments, and the aim was to investigate the influence of music on emotions, approach/avoidance behavior. Paper II comprised two experiments, and the aim was to investigate the effect of frontline employees’ personal self-disclosure on consumers’ reciprocal behavior. Paper III comprised three experiments, and the aim was to investigate the influence of employee’s direct eye gaze/ averted eye gaze on consumer emotions, social impression of the frontline employee and encounter satisfaction in different purchase situations.The results in this thesis show that music affects consumers in both positive and negative ways (Paper I). Self-disclosure affects consumers negatively, in such a way that it decreases encounter satisfaction (Paper II) and, finally, eye gaze affects consumers by regulating both positively – and in some cases also negatively – consumers’ social impression of the frontline employee and their encounter satisfaction (Paper III).The conclusions of this thesis are that both ambient and social stimuli in a servicescape affect consumers’ internal responses, which in turn affect their behavior. Depending on the purchase situation, type of retail, and stimuli, the internal and behavioral responses are different.
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| 5. |
- Bjureland, William
(author)
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Reliability-based design of rock tunnel support
- 2020
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Doctoral thesis (other academic/artistic)abstract
- Since 2009, design of rock tunnels can be performed in accordance with the Eurocodes, which allows that different design methodologies are applied, such as design by calculation or design using the observational method. To account for uncertainties in design, the Eurocode states that design by calculation should primarily be performed using the partial factor method or reliability-based methods. The basic principle of both of these methods is that it shall be assured that a structure’s resisting capacity is larger than the load acting on the structure, with sufficiently high probability. Even if this might seem straightforward, the practical application of limit state design to rock tunnel support has only been studied to a limited extent.The overall aim of this project has been to develop reliability-based methods for environmental and economic optimization of rock tunnel support, with a special focus on shotcrete support. To achieve this, this thesis aims to: (1) assess the applicability of the partial factor method and reliability-based methods for design of shotcrete support, exclusively or in combination with the observational method, (2) quantify the magnitude and uncertainty of the shotcrete’s input parameters, and (3) assess the influence from spatial variability on shotcrete’s load-bearing capacity and judge the correctness of the assumption that the load-bearing capacity of the support is governed by the mean values of its input parameters.The thesis shows that the partial factor method is not suitable, and in some cases not applicable, to use in design of rock tunnel support. Instead, the thesis presents a reliability-based design methodology for shotcrete in rock tunnels with respect to loose blocks between rockbolts and a design methodology for shotcrete lining based on a combination of the observational method and reliability-based methods. The presented design methodologies enable optimization of the shotcrete support and shotcrete lining by stringently accounting for uncertainties related to input data throughout the design process. The thesis also discusses the limited knowledge that we as an industry sometimes have in our calculation models and the clarifications that should be made in future revisions of the Eurocode related to target reliability and the definition of failure.
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| 6. |
- Ebeling Barbier, Charlotte, 1969-
(author)
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Myocardial Scars on MRI : Their Prevalence and Possible Impact
- 2007
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Doctoral thesis (other academic/artistic)abstract
- Myocardial infarction (MI) causes high morbidity and mortality worldwide and for effective prevention and treatment MIs have to be adequately detected.The existence of clinically unrecognized MIs (UMIs) has been known for the past hundred years, but an ultimate tool for their detection has not yet been found. Using persistent Q waves on electrocardiography as a sign of MI, it has been estimated that UMIs constitute at least ¼ of all MIs and have mortality rates similar to those of recognized MIs (RMIs). These estimates are misleading, however, since persistent Q waves do not necessarily represent MIs.The late enhancement technique in magnetic resonance imaging (LE MRI) has been developed over the past decade and accurately determines myocardial viability. The aim of this research was to investigate the prevalence and impact of UMI and RMI in a population-based sample of 70-year-olds, assessed with MRI.Cardiac function and viability were examined with MRI in 259 randomly selected 70-year-old subjects (127 women, 132 men) participating in a larger population-based study (PIVUS). Information on other parameters of cardiovascular disease was obtained and related to the findings.Three methods for segmentation of the left ventricular mass were used in the first 100 subjects; these differed in accuracy and led to differences in systolic function values. In the subsequent 159 examinations one of the segmentation methods was used.The viability images were assessable in 248 subjects (123 women, 125 men). Among these, the prevalence of UMI, 19.8%, definitely exceeded the expectations and UMIs constituted 4/5 of all MIs. The prevalence of RMI was 4.4%. MRI-detected UMIs differed from RMIs in several respects; they were smaller, frequently located inferolaterally, did not appear to be associated with atherosclerosis, and displayed increased collagen turnover. The pathogenesis of these UMIs remains to be investigated, but our observations suggest that they are caused by ischemia. Subjects with UMI showed increased cardiac morbidity, a decreased ejection fraction and an increased left ventricular mass, indicating an increased cardiovascular risk.It is thus important to detect these UMIs, and this is adequately achieved by LE MRI. However, to decide upon prevention and treatment of these UMIs we need to know more about their pathogenesis and prognosis.
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| 7. |
- Johansson, Fredrik
(author)
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Evaluating the performance of TEWA systems
- 2010
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Doctoral thesis (other academic/artistic)abstract
- It is in military engagements the task of the air defense to protect valuable assets such as air bases from being destroyed by hostile aircrafts and missiles. In order to fulfill this mission, the defenders are equipped with sensors and firing units. To infer whether a target is hostile and threatening or not is far from a trivial task. This is dealt with in a threat evaluation process, in which the targets are ranked based upon their estimated level of threat posed to the defended assets. Once the degree of threat has been estimated, the problem of weapon allocation comes into the picture. Given that a number of threatening targets have been identified, the defenders need to decide on whether any firing units shall be allocated to the targets, and if so, which firing unit to engage which target. To complicate matters, the outcomes of such engagements are usually stochastic. Moreover, there are often tight time constraints on how fast the threat evaluation and weapon allocation processes need to be executed. There are already today a large number of threat evaluation and weapon allocation (TEWA) systems in use, i.e. decision support systems aiding military decision makers with the threat evaluation and weapon allocation processes. However, despite the critical role of such systems, it is not clear how to evaluate the performance of the systems and their algorithms. Hence, the work in thesis is focused on the development and evaluation of TEWA systems, and the algorithms for threat evaluation and weapon allocation being part of such systems. A number of algorithms for threat evaluation and static weapon allocation are suggested and implemented, and testbeds for facilitating the evaluation of these are developed. Experimental results show that the use of particle swarm optimization is suitable for real-time target-based weapon allocation in situations involving up to approximately ten targets and ten firing units, while it for larger problem sizes gives better results to make use of an enhanced greedy maximum marginal return algorithm, or a genetic algorithm seeded with the solution returned by the greedy algorithm.
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| 8. |
- Johansson, Hans-Erik, 1960-
(author)
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The Impact of Bariatric Surgery on Obesity related Metabolic Traits with Specific Emphasis on Glucose, Insulin and Proinsulin
- 2010
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Doctoral thesis (other academic/artistic)abstract
- Hyperproinsulinemia is associated with type 2 diabetes (T2DM) and obesity and is a predictor for future coronary heart disease. This thesis examines the effect of bariatric surgery on glucometabolic status including insulin and proinsulin responses after meal. Further we explored longitudinally the effects of bariatric surgery on glucose, insulin and proinsulin secretion as well as lipids, liver enzymes and magnesium concentrations. We explored by a standardised meal test the postprandial dynamics of proinsulin and insulin and effects on glucose and lipids in patients treated with gastric bypass (RYGBP) surgery and in patients treated with bileopancreatic diversion with duodenal switch surgery (BPD-DS). Comparisons were made to morbidly obese patients and normal weight controls (NW). RYGBP surgery markedly lowers fasting and postprandial proinsulin concentrations although BMI was higher compared to NW-controls. BPD-DS surgery induces a large weight loss and normalises postprandial responses of glucose, proinsulin and insulin and markedly lowers triglycerides. We evaluated non-diabetic morbidly obese patients who underwent bariatric surgery followed-up for up to four years after surgery. Long-term follow-up showed that RYGBP surgery is not only characterized by markedly and sustained lowered BMI but also lowered concentrations of proinsulin, insulin, ALT and increased HDL-C possibly via reduced hepatic insulin resistance. We also examined how magnesium status is affected by bariatric surgery as magnesium has been shown to be inversely related to glucose and to insulin resistance. The serum magnesium concentrations increased by 6% after RYGBP and 10% after BPD-DS. In summary, RYGBP and BPD-DS surgery results in marked weight loss, alterations in insulin and proinsulin dynamics, lowered fasting and postprandial proinsulin concentrations and improved glucometabolic and magnesium status.
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| 9. |
- Johansson, Kristina, 1986-
(author)
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Biomarkers and risk of intracerebral hemorrhage : population-based studies in northern Sweden
- 2021
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Doctoral thesis (other academic/artistic)abstract
- BackgroundIntracerebral hemorrhage (ICH) is a disease associated with a high morbidity and mortality and treatment options for the condition are limited. Even though an ICH event usually comes as a surprise to the affected individual, pathogenetic processes often have occurred before the sudden ICH event and may have preceded disease onset by years. It is possible that individuals at increased risk of ICH could be identified using biomarkers, for example markers of hemostasis and fibrinolysis. Even if these biomarkers are not part of the causal chain, they could be used as risk indicators to better define high-risk groups. Another approach could be to measure already established risk markers for ICH, such as self-reported alcohol consumption, using a blood biomarker. That could increase measurement reliability and consequently the accuracy of the estimates of ICH risk.AimsThe aim of this thesis was to investigate potential biomarkers and risk of ICH. Specific aims were to evaluate the associations between factor XII, D-dimer, von Willebrand factor (VWF), ABO blood groups with focus on blood group O, phosphatidylethanol (PEth), and risk of ICH.MethodsIn our first study, aiming to investigate the association between factor XII and risk of hemorrhagic stroke, we followed participants of the health examination northern Sweden MONItoring trends and determinants in CArdiovascular disease (MONICA) performed in 1994 as a cohort until 2011. Factor XII concentrations were measured in blood samples drawn at the baseline health examination where the participants also answered a questionnaire regarding lifestyle factors and medical history. Diagnosis codes from the National Patient Register and the Swedish Cause of Death Register were used to find cases of hemorrhagic stroke, defined as ICH or subarachnoid hemorrhage. In the subsequent studies, the associations between biomarkers (factor XII, D-dimer, VWF, ABO blood groups, and PEth) and risk of ICH were investigated using a matched, nested case-referent design including individuals that had participated in the Västerbotten Intervention Programme, the MONICA and the Mammography Screening Project in 1985–2007. The participants donated blood samples at baseline for future research which were stored at -80 degrees C until biomarker analyses. The majority of the participants also underwent a baseline health examination including a questionnaire. First-ever ICH diagnoses during the study period 1985–2007 were validated using medical records and autopsy reports. To each case, two referents were matched for age, sex, geographical region, health examination date and health examination setting. ResultsIn the cohort study of the association between factor XII concentrations and risk of hemorrhagic stroke, 1,852 participants were included among which 30 experienced a hemorrhagic stroke event. There was an association between high factor XII and risk of hemorrhagic stroke in a multivariable model (hazard ratio 1.51; 95% confidence interval [CI] 1.03–2.21 per standard deviation [SD] of factor XII). In the case-referent study of the association between factor XII and risk of ICH, 70 cases with ICH and 137 matched referents were included. We found no association between factor XII and risk of ICH in a multivariable model (odds ratio [OR] 1.06; 95% CI 0.57–1.97 per SD of factor XII). The study of the association between D-dimer and risk of ICH included 141 cases and 255 matched referents. We found an association between D-dimer and risk of ICH in a multivariable model (OR 1.36; 95% CI 1.05–1.77 per SD of D-dimer). When stratifying the analysis for time between blood sampling and ICH event in tertiles, the association remained significant in the cases with the shortest time between blood sampling and ICH event in a multivariable model (OR 1.78; 95% CI 1.05–3.05 per SD of D-dimer). The study investigating the association between VWF and risk of ICH included 139 cases and 276 referents. We found no association between VWF and risk of ICH in a multivariable model (OR 0.85; 95% CI 0.54–1.34 per SD of VWF). In the analysis investigating the associations between ABO blood groups and risk of ICH, 162 cases and 317 referents were included. We found no association between blood group O compared to non-O blood groups and risk of ICH (OR 0.96; 95% CI 0.65–1.42). In the study of the association between PEth concentrations and risk of ICH, 97 cases and 180 referents were included. There was an association between PEth concentrations > 0.30 µmol/L compared to < 0.01 µmol/L and risk of ICH in a multivariable model (OR 4.64; 95% CI 1.49–14.40).ConclusionsHigh concentrations of D-dimer and PEth are associated with an increased risk of ICH. Our conclusion of the two studies investigating the association between factor XII and risk of hemorrhagic stroke and ICH respectively is that there is no association between factor XII and risk of ICH. We found no association between VWF or blood group O and risk of ICH.
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| 10. |
- Mohammadi, Mohammad
(author)
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Probabilistic time estimation in tunnel projects
- 2021
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Licentiate thesis (other academic/artistic)abstract
- Transport infrastructure projects, including tunneling, suffer from timedelays and cost overrun. A literature review shows that the effect ofuncertainty has been neglected in explaining time and cost overrunmeaning that technical explanations matter. Probabilistic estimations oftime and cost can be employed for dealing with uncertainty in transportinfrastructure projects.In this licentiate thesis, KTH’s probabilistic time and cost estimationmodel for tunneling projects (Isaksson and Stille, 2005, Rock Mech. RockEng., 38, 373-398) was improved. The improvements include breakingdown the production activities into their sub-activities, which form thebasis for assessing times (or costs) for tunnel construction. In addition, theexceptional time and the length of model’s geotechnical zones aredescribed as stochastic variables instead of deterministic values used in theoriginal model. Given its hierarchical structure, the model can be used fortime and cost estimation of all types of tunnels and all constructionmethods in various geological condition.The improved version of the model uses three types of input parametersthat are probabilities of occurrences of different geological condition andidentified undesirable events, production effort of sub-activities (i.e. timespent for performing the sub-activity per unit length of tunnel) andadditive delay time that is imposed as a result of occurrence of undesirableevents. The important issues in modeling the uncertainty in the productionefforts of sub-activities are also explained.
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