| 1. |
- Fridriksson, Jon Örn, 1981-
(författare)
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Adverse effects of curative treatment of prostate cancer
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Screening for prostate cancer is debated, there is conflicting data on the net benefit of screening. Men who consider screening need to be informed on the pros and cons. Rehospitalization after surgery can be used as an indicator of general quality of care. For radical prostatectomy, little is known on the readmission rate after surgery. Men diagnosed with low- and intermediate-risk prostate cancer have low prostate-cancer specific mortality. However, adverse effects after curative treatment can be severe and decrease quality of life. Curative treatments for prostate cancer differ mainly in the pattern of adverse effects but detailed analysis of long-term adverse effects is lacking.The aim of this thesis was to assess the perioperative quality of radical prostatectomy and the risk of adverse effects after curative treatment for prostate cancer.Material and Methods In this thesis, data from the National Prostate Cancer Register (NPCR) and other nationwide Swedish registers were used. By use of the Swedish personal identity number, NPCR was cross-linked to other registers creating Prostate Cancer data Base Sweden (PCBaSe), a large dataset for research.Results The proportion of men who had received information on the pros and cons of screening for prostate cancer with PSA testing was low (14%) indicating that the majority of men who were screened did not make an informed decision. The risk of rehospitalization within 90 days after radical prostatectomy was approximately 10% and similar after retropubic and robot-assisted radical prostatectomy. Compared to controls, there was an increased risk of adverse effects after both radiotherapy and radical prostatectomy up to twelve years after treatment and the overall risk was quite similar after retropubic and robot-assisted radical prostatectomy.Conclusion Improved information to men on the pros and cons of PSA screening is warranted. The risk of adverse effects was elevated up to 12 years after curative treatment for prostate cancer. The pattern of adverse effects was different after radiotherapy and radical prostatectomy but quite similar after retropubic and robot-assisted radical prostatectomy.
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| 2. |
- Holmgren, Theresa, 1974-
(författare)
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Exercise treatment of patients with long-standing subacromial pain
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Subacromial pain is the most common problem among patients with shoulder complaints seeking primary care. The recommended treatment for these patients is primarily non-surgical with a focus on exercise treatment. If this treatment fails arthroscopic subacromial decompression (ASD) followed by exercise treatment is recommended. Surgical treatment with ASD has increased substantially in Sweden in recent years even though studies comparing exercise treatment with surgery report equally positive results. Still, there is a need of evidence based preand postoperative exercise treatments, standardised and described in detail, to guide treatment of these patients in clinical practice.The overall aim of this thesis was to evaluate the efficacy of pre- and postoperative exercise strategies on shoulder function and how the preoperative strategy affects the need for surgery in patients with long-standing subacromial pain.This thesis comprises four papers which are based on two randomised controlled trials. In study A, patients were randomised after ASD surgery to either physical therapist (PT) supervised strength-endurance exercises for the rotator cuff and scapula stabilisers or to home-based movement exercises for a period of three months. Shoulder function and pain, health related quality of life and return to work was evaluated for 6 months (paper I). In study B, patients on the waiting list for surgery were randomised to either specific exercise strategy with strengthendurance exercises for the rotator cuff and the scapula stabilisers or to control exercises with movement exercises for the neck and shoulders for a period of three months. After completing the exercise program and also after 12 months, shoulder function and pain, need for surgery and health related quality of life was evaluated. Baseline shoulder function, rotator cuff status and radiological findings were analysed in relation to the choice of surgery (paper II, III). The minimal important clinical change (MIC) of the Constant-Murley (CM) score, used as primary outcome in this thesis, was determined by using a visual anchor-based MIC distribution method (paper IV).Six months after ASD surgery, patients who performed PT-supervised strength-endurance exercises improved significantly more in shoulder function and pain compared to patients who had performed home-based movement exercises (paper I). Patients on the waiting list for surgery who performed specific strength-endurance exercises had significantly greater improvements in shoulder function and pain compared to patients performing movement exercises (paper II). A significantly lower proportion of those performing specific strength-endurance exercises chose surgery at the three- and 12 months follow-ups (paper II, paper III). Low baseline values in shoulder function and pain measured with the CM score and/or having a full thickness rotator cuff rupture were associated with an increased risk of choosing surgery (paper III). Regarding the CM score, a change between 17-24 points seems to be clinically important for patients with long-standing subacromial pain (paper IV).Supervised strength-endurance exercises seem to be more effective than home-based movement exercises after ASD surgery. For patients on the waiting list for surgery, the specific strategy of strength-endurance exercises was effective in improving shoulder function and pain and the need for surgery was reduced at 12 months. Low baseline values for shoulder function and pain measured with the CM score and/or having a full thickness rotator cuff tear seem to be predictors for choosing surgery. The CM score is able to detect the MIC in individual patients with long-standing subacromial pain when the rotator cuff is intact. In all patients with longstanding subacromial pain, the MIC value was dependent on the subgroup as well as the choice of statistical analysis.
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| 3. |
- Johansson, Jonas, 1984-
(författare)
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The Healthy Ageing Initiative : Prevention of falls and fractures
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The world is currently experiencing a dramatic increase in the number of older individuals, an amount that is expected to double between 2015 and 2050. This increase will likely affect the prevalence of age-related functional impairments, such as those caused by fractures. Fractures are often immobilizing events leading to increased individual suffering and vast healthcare costs. Prevention of these events and detection of underlying risk factors are hence of utmost importance. Fracture prevention strategies have traditionally focused on strengthening the skeleton by improving bone mineral density, partly through the mechanical load of increased physical activity. However, research has shown that nine out of ten hip fractures are attributed to falls. While several risk factors behind falls have been identified, there is less knowledge about how aspects such as gait patterns and postural stability predict future falls. The aim of this thesis was to expand upon the current knowledge by investigating objective measures of physical activity in relation to bone parameters, and measures of gait patterns and postural stability in relation to incident falls, in a large population-based sample of 70-year-olds.The samples investigated in the four included studies were drawn from the Healthy Ageing Initiative (HAI) cohort. Study I examined associations between physical activity, objectively measured using accelerometers, and bone parameters, measured by Dual-energy X-ray Absorptiometry and Peripheral Quantitative Computed Tomography. Study II examined how gait variability, measured using the GAITRite electronic walkway system, predicted incident falls in men and women. Studies III and IV examined how center of pressure (COP) sway and limits of stability (LOS), measured using a force platform, predicted incident falls. Independent prediction of bone parameters and incident falls were investigated using multiple linear and logistic regression models.Study I revealed that moderate-to-vigorous physical activity and vertical peak acceleration independently predicted parameters of bone in the weight-bearing skeleton. Study II showed that women’s increased risk of falling could be explained by increased gait variability during dual-task assignments. Study III revealed that the risk of falling was increased by 75-90% for individuals in the highest quintile of COP sway. Study IV integrated COP and LOS data, showing that fall risk was increased by 9-16% per 1-unit increase in COP-LOS ratio. In conclusion, this thesis highlighted several objective predictors of incident falls among older adults. Future studies and recommendations should emphasize strategies to improve balance, muscle strength and physical activity in order to prevent falls and fractures.
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| 4. |
- Bredvold, Randi, 1957-
(författare)
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Entreprenørers fortellinger : en identitetsstudie i det opplevelsesbaserte reiselivet
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This is a narrative study in which five entrepreneurs in the experience-based tourist industry have told their life-stories in connection with their establishing and running their own enterprises. Over the last decades the number of adventure-based companies has markedly increased in tourist industry, but the knowledge gained through the research on the persons who establish these companies is scant. Through focusing on the constructions of identity of the entrepreneurs, this study gives nuanced pictures of the chain of events that had lead an individual to establish one`s own company. In addition, these pictures offer deeper understanding of how these individuals perceive themselves as the founder and manager of an experience-based company. Over the last decades research in entrepreneurship has criticized the imbalanced focus on the entrepreneurs' personal characteristics and it's use as an explanation of their entrepreneurial activities. In the same critical vein I question whether motivational studies are able to explain why certain individuals choose to establish their own business. Indeed, these five stories show that an entrepreneur is not something one is but something one becomes. Although the concept of an experiential economy appeared at the end of the 1990s, the production of experiences has a long tradition in the tourist industry. Norwegian tourism has faced an uphill struggle for several decades, which worries both the authorities and the industry itself. In recent decades the focus has been directed more and more on the dimension of experience. One hopes that the creation of new and attractive adventures will help to reverse the negative trend in the industry. Effecting this reversal places a heavy responsibility on the entrepreneurs since they are to be the driving force in this process. Tourist adventures have been one of several core themes within the field of research in tourism for decades, but this focus has mainly been on the perspective of the consumer. In contrast, this study concentrates on the producers, a group about whom we know much less. The five entrepreneurs who tell their story in this study give detailed descriptions of their life until the establishment of their businesses, and we see that each of them describes a number of causal chains that are interwoven and together create a meaningful picture of their choice. Through focusing on their reflexive identity-constructions and viewing these in light of the concrete situations they were in, before they established their enterprises, we gain a deeper understanding of this choice. Through the process of categorizing these reflexive identity-constructions, three distinct ontological positions emerge, that is, different ways in understanding reality. The study shows that there is a connection between these ontological positions and the ways that the entrepreneurs run their businesses, as well as their understanding of how they create and produce adventures for their guests.
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| 5. |
- Garpebring, Anders, 1980-
(författare)
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Contributions to quantitative dynamic contrast-enhanced MRI
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Dynamic contrast-enhanced MRI (DCE-MRI) has the potential to produce images of physiological quantities such as blood flow, blood vessel volume fraction, and blood vessel permeability. Such information is highly valuable, e.g., in oncology. The focus of this work was to improve the quantitative aspects of DCE-MRI in terms of better understanding of error sources and their effect on estimated physiological quantities. Methods: Firstly, a novel parameter estimation algorithm was developed to overcome a problem with sensitivity to the initial guess in parameter estimation with a specific pharmacokinetic model. Secondly, the accuracy of the arterial input function (AIF), i.e., the estimated arterial blood contrast agent concentration, was evaluated in a phantom environment for a standard magnitude-based AIF method commonly used in vivo. The accuracy was also evaluated in vivo for a phase-based method that has previously shown very promising results in phantoms and in animal studies. Finally, a method was developed for estimation of uncertainties in the estimated physiological quantities. Results: The new parameter estimation algorithm enabled significantly faster parameter estimation, thus making it more feasible to obtain blood flow and permeability maps from a DCE-MRI study. The evaluation of the AIF measurements revealed that inflow effects and non-ideal radiofrequency spoiling seriously degrade magnitude-based AIFs and that proper slice placement and improved signal models can reduce this effect. It was also shown that phase-based AIFs can be a feasible alternative provided that the observed difficulties in quantifying low concentrations can be resolved. The uncertainty estimation method was able to accurately quantify how a variety of different errors propagate to uncertainty in the estimated physiological quantities. Conclusion: This work contributes to a better understanding of parameter estimation and AIF quantification in DCE-MRI. The proposed uncertainty estimation method can be used to efficiently calculate uncertainties in the parametric maps obtained in DCE-MRI.
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| 6. |
- Gisslén, Karl, 1967-
(författare)
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The patellar tendon in junior elite volleyball players and an Olympic elite weightlifter
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The principal aim of the present thesis was to prospectively follow (clinical status and ultrasound + Doppler findings) the patellar tendons in the young elite volleyball players at the Swedish National Centre for high school volleyball in Falköping. In an Olympic weightlifter with chronic painful jumper´s knee, the effects of treatment with sclerosing injections followed by early instituted very heavy weightlifting training, was also evaluated. First, in a prevalence study, we demonstrated that the clinical diagnosis patellar tendinopathy-jumper’s knee, together with structural tendon changes and vascularisation in the painful area of the tendon, was demonstrated in 12/114 tendons in Swedish junior elite volleyball players, but not in any tendons of individually matched (age, height and weight) not regularly sports active controls. Structural tendon changes alone was demonstrated among the volleyball players but also among the controls. In a 7 months prospective study of a total of 120 tendons, we demonstrated that the clinical diagnosis patellar tendinopathy-jumper’s knee was associated with neovessels/vascularity in the area with structural tendon changes in 17/19 tendons. Seventy tendons that at start were clinically normal, and had normal ultrasound + Doppler findings, remained clinically normal after 7 months with intensive training and playing volleyball. In a 3-year prospective study it was demonstrated that normal clinical tests and normal ultrasound + Doppler findings at school start, indicated a low risk (8%) for these players to sustain patellar tendinopathy-jumper’s knee during the 3 school years with intensive training and playing. In a case study, involving an Olympic elite weightlifter with chronic painful patellar tendinopathy-jumper’s knee, successful treatment with ultrasound and Doppler-guided injection of the sclerosing agent polidocanol, allowed for pain-free very heavy weight training two weeks after treatment. Further heavy weightlifting training on a daily basis, preparing for European Championships, was done without causing tendon rupture and/or pain. Key words: Jumper’s knee, Patellar tendinopathy, Chronic pain, Ultrasonography, Doppler, Neovascularisation, Volleyball, Weightlifting
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| 7. |
- Karlsson, Karl-Göran, 1959-
(författare)
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The use of a satellite-derived cloud climatology for studying cloud-aerosol processes and the performance of regional cloud climate simulations
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The entry of satellite-derived decadal cloud datasets with homogeneous coverage in time and space enables studies not possible before. This thesis presents two such applications. The first study deals with cloud-aerosol processes and the second with an evaluation of cloud simulations from a regional climate model.The first part of the thesis describes the used satellite-derived dataset based on imagery from the Advanced Very High Resolution Radiometer (AVHRR) on the polar orbiting NOAA satellites. A method for cloud retrieval and the compilation of a 1991-2000 Scandinavian cloud climatology are described.The second part reveals an intriguing anti-correlation between monthly mean satellite-derived cloudiness and the concentration of the cosmogenetic isotope Beryllium-7 in near-surface aerosol samples for three measurement sites in Sweden. Large-scale transport processes are suggested as the most likely physical mechanism for this behaviour but more complex relations to cloud microphysical processes are not ruled out.The final part presents a thorough evaluation of cloud simulations of the SMHI Rossby Centre regional atmospheric model (RCA3). Several model-to-satellite adaptations are applied to avoid artificial biases of results. The study stresses the necessity to account for initial differences between observed and modelled clouds caused by satellite cloud detection limitations. Results show good agreement of modelled and observed cloud amounts while the vertical distribution of clouds appears largely different. RCA3 underestimates medium-level clouds while overestimating low- and high-level clouds. Also, the current use of the Maximum cloud overlap approach in the radiation scheme and an indicated excess of cloud condensate in modelled clouds appear to create excessive cloud optical thicknesses with serious implications for the surface radiation budget.Future applications are outlined based on greatly enhanced satellite-derived cloud and radiation budget datasets.
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| 8. |
- Schepull, Thorsten
(författare)
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Stiffness of the healing human Achilles tendon
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Achilles tendon ruptures in humans are followed by a long period of immobilisation, rehabilitation and limitations of physical activity and sometimes work also. This prolonged period probably leaves a marginal for improvement in the management of this injury. Animal studies have shown that there are several possibilities to influence and improve tendon healing.The aim of this thesis was to find a way to examine the mechanical properties of the healing human Achilles tendon and, by using that method, to gain a better understanding of the tissue properties and healing process in these tendons. It was also our aim to use our knowledge from animal studies in an attempt to improve tendon healing in humans.We developed a radiological method using radiostereophotogrammetric analysis (RSA) and computed tomography (CT), which enabled us to measure the stiffness of the healing Achilles tendon. The results of these measurements, as early as 7 weeks after injury correlated with the late clinical results in all studies. Clinical results were measured using a heel-raise test comparing the injured with the non-injured tendon. We could not find a significant difference in stiffness between patients treated surgically or non-surgically. Neither could we demonstrate that platelet-rich plasma improved the mechanical properties of the healing tendon or the clinical outcome, within the limits of the statistical power. In contrast, patients following a specific training programme with early tension loading of the tendon twice a day developed stiffer tendon tissue later in the healing process.Since RSA is unsuitable for routine clinical use, we evaluated the possibility to use radiodensity findings from CT as a proxy for healing and its correlation to mechanical and clinical results. Density and mechanical properties correlated strongly when analysing all time points together, but only weakly at each particular point in time. Density may still be useful in describing mechanical properties at a later stage of repair, but this remains to be seen.In conclusion, these studies show that early mechanical properties correlate to late clinical outcome and that the early use of daily tension loading sessions leads to an improvement in the mechanical properties of the tendon tissue.
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| 9. |
- Högström, Magnus, 1956-
(författare)
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Vitamins, fatty acids, physical activity and peak bone mass
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Osteoporosis is a disease characterized by low bone mineral density, deteriorated bone microstructure and increased fracture risk. About 50% of all women and 25% of all men will have an osteoporotic fracture. Given that there is no effective cure in established osteoporosis, prevention is of high importance. Bone mineral density (BMD) is accumulated during childhood and adolescence with a peak at about 20 years of age. Peak BMD has been suggested to explain at least half of the variation in BMD up to old age. Thus, to increase peak BMD could decrease the risk of later fractures. The purpose of the present thesis was to investigate the influence of physical activity, vitamins A and D, and fatty acids on peak bone mass in men. The influence of physical activity on bone accrual was studied in two cohorts. In the first cohort 46 ice hockey players, 18 badminton players and 27 controls, all 17 years of age at baseline, were followed for four years. During the follow up the badminton players gained more bone mass at the hip compared to both the ice hockey players and controls. In the second cohort the associations between physical activity and BMD were investigated in 62 female and 62 male young medical students. The estimated high impact activity per week was associated with bone mass at all sites in the male medical students (r=0.27-0.53, p<0.05). In the female cohort different estimates of physical activity were not related to bone mass at any site. In both males and females correlations between bone mass and body constitution parameters were observed. Levels of vitamin D3, vitamin D2, retinol, retinol-binding-protein-4 (RBP-4) and fatty acids were measured in 78 young men with a mean age of 22.6 years. BMD at various sites were measured using Dual-Energy X-ray absorptiometry. Levels of vitamin D3 showed a significant positive association with all BMD sites and also lean body mass (r=0.23-0.35, p<0.05). Levels of vitamin D2, however, showed a significant negative correlation with BMD of the total body (r=-0.28, p=0.01) and spine (r=-0.27, p=0.02). There was also a significant negative relationship between levels of vitamin D3 and D2 (r=-0.31, p=0.006). Concentrations of n-3 (omega-3) fatty acids showed a positive association with BMD at the total body (r=0.27, p=0.02) and spine BMD (r=0.25, p=0.02). There was also a positive association between levels of n-3 fatty acids and changes in BMD of the spine between 16 and 22 years of age (r=0.26, p=0.02). The significant associations found seemed to be related mostly to the concentration of the n-3 fatty acid docosahexaenoic acid. Levels of retinol and RBP-4 were not related to BMD but to levels of osteocalcin, which is a marker of bone formation. This association disappeared when adjusting for the influence of abdominal fat mass. In summary, the present thesis suggests that many modifiable factors may influence the accumulation of peak bone mass in males, such as physical activity, vitamins, and fatty acids. Further studies are needed to investigate whether optimizing these factors in youth may decrease the risk of osteoporosis later in life.
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| 10. |
- Tervo, Taru, 1972-
(författare)
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Physical activity, bone gain and sustainment of peak bone mass
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Weak and osteoporotic bones are an increasing cause of mortality and painful physical impairment among the elderly, especially in the Western world. Bone mineral density (BMD, g/cm2) accrual during childhood and adolescence is thought to influence an individual’s risk of osteoporosis and the related fractures. A main aim of this thesis is to investigate the effects that various types of weight-bearing physical activity have on bone accretion in young males during their active sports careers and to study the effects that detraining has on BMD. The results suggest that bone is sensitive to loading after puberty in males, and important gains in BMD stemming from physical activity were observed during the 12-year follow-up period (papers I-III). These gains seem to be site-specific and related to the type and amount of physical activity in which individuals participate (papers I-III). For example, badminton, a sport that is characterized by jumps and rapid versatile moments in multiple directions was associated with greater gains in BMD than ice hockey was. In addition, our results indicate that with reduced training, exercise-induced bone benefits decline, predominantly at trabecular sites (paper II). In contrast, high bone density attained from previous physical loading was partially preserved at cortical bone sites after about eight years of reduced activity (papers I-II). In study IV, the associations between self-perceived health, BMD, and other lifestyle factors were studied in a well-defined group of women and men of varying ages. We found that self-perceived health was related to several lifestyle factors, such as physical activity, which were also related to BMD at the femoral neck. In summary, BMD in young males seem to be especially sensitive to activities associated with supposed high strains in unusual directions at specific bone sites. A high bone density stemming from previous weight-bearing physical activity is largely lost at trabecular bone sites with reduced physical activity levels. Finally, self-perceived health seems to be associated with several lifestyle factors that are also associated with BMD at the femoral neck.
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