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  • 1.
    Abramowicz, Konrad
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Häger, Charlotte
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik.
    Hérbert-Losier, Kim
    National Sports Institute of Malaysia.
    Pini, Alessia
    MOX – Department of Mathematics, Politecnico di Milano.
    Schelin, Lina
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik. Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Fysioterapi.
    Strandberg, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för matematik och matematisk statistik.
    Vantini, Simone
    MOX – Department of Mathematics, Politecnico di Milano.
    An inferential framework for domain selection in functional anova2014Inngår i: Contributions in infinite-dimensional statistics and related topics / [ed] Bongiorno, E.G., Salinelli, E., Goia, A., Vieu, P, Esculapio , 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present a procedure for performing an ANOVA test on functional data, including pairwise group comparisons. in a Scheff´e-like perspective. The test is based on the Interval Testing Procedure, and it selects intervals where the groups significantly differ. The procedure is applied on the 3D kinematic motion of the knee joint collected during a functional task (one leg hop) performed by three groups of individuals.

  • 2.
    Abramsson, Evelina
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Grind, Kajsa
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Skattning av kausala effekter med matchat fall-kontroll data2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
  • 3.
    Andersson, Björn
    et al.
    Uppsala universitet.
    Bränberg, Kenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    kequate: The kernel method of test equating. R package version 1.1.02012Annet (Annet vitenskapelig)
    Abstract [en]

    Implements the kernel method of test equating using the CB, EG, SG, NEAT CE/PSE and NEC designs, supporting gaussian,logistic and uniform kernels and unsmoothed and pre-smoothed input data.

  • 4.
    Andersson, Björn
    et al.
    Uppsala universitet.
    Bränberg, Kenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Performing the Kernel Method of Test Equating with the Package kequate2013Inngår i: Journal of Statistical Software, ISSN 1548-7660, Vol. 55, nr 6, 1-25 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In standardized testing it is important to equate tests in order to ensure that the test takers, regardless of the test version given, obtain a fair test. Recently, the kernel method of test equating, which is a conjoint framework of test equating, has gained popularity. The kernel method of test equating includes five steps: (1) pre-smoothing, (2) estimation of the score probabilities, (3) continuization, (4) equating, and (5) computing the standard error of equating and the standard error of equating difference. Here, an implementation has been made for six different equating designs: equivalent groups, single group, counter balanced, non-equivalent groups with anchor test using either chain equating or post- stratification equating, and non-equivalent groups using covariates. An R package for the kernel method of test equating called kequate is presented. Included in the package are also diagnostic tools aiding in the search for a proper log-linear model in the pre-smoothing step for use in conjunction with the R function glm.

  • 5.
    Andersson, Björn
    et al.
    Statistiska institutionen, Uppsala universitet.
    Waernbaum, Ingeborg
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Sensitivity analysis of violations of the faithfulness assumption2014Inngår i: Journal of Statistical Computation and Simulation, ISSN 0094-9655, E-ISSN 1563-5163, Vol. 84, nr 7, 1608-1620 s.Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    We study implications of violations of the fatihfulness condition due to parameter cancellations on estimation of the DAG skeleton. Three settings are investigated: when i) faithfulness is guaranteed ii) faithfulness is not guaranteed and iii) the parameter distributions are concentrated around unfaithfulness (near-unfaithfulness). In a simulation study the effetcs of the different settings are compared using the PC and MMPC algorithms. The results show that the performance in the faithful case is almost unchanged compared to the unrestricted case whereas there is a general decrease in performance under the near-unfaithful case as compared to the unrestricted case. The response to near-unfaithful parameterisations is similar between two algorithms, with the MMPC algorithm having higher true positive rates and the PC algorithm having lower false positive rates.

  • 6.
    Andersson, Björn
    et al.
    Beijing Normal University.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Item response theory observed-score kernel equating2017Inngår i: Psychometrika, ISSN 0033-3123, E-ISSN 1860-0980, Vol. 82, nr 1, 48-66 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Item response theory (IRT) observed-score kernel equating is introduced for the non-equivalent groups with anchor test equating design using either chain equating or post-stratification equating. The equating function is treated in a multivariate setting and the asymptotic covariance matrices of IRT observed-score kernel equating functions are derived. Equating is conducted using the two-parameter and three-parameter logistic models with simulated data and data from a standardized achievement test. The results show that IRT observed-score kernel equating offers small standard errors and low equating bias under most settings considered.

  • 7.
    Andersson Tano, Ingrid
    et al.
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Vännman, Kerstin
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    A multivariate process capability index based on the first principal component only2013Inngår i: Quality and Reliability Engineering International, ISSN 0748-8017, E-ISSN 1099-1638, Vol. 29, nr 7, 987-1003 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Often the quality of a process is determined by several correlated univariate variables. In such cases, the considered quality characteristic should be treated as a vector. Several different multivariate process capability indices (MPCIs) have been developed for such a situation, but confidence intervals or tests have been derived for only a handful of these. In practice, the conclusion about process capability needs to be drawn from a random sample, making confidence intervals or tests for the MPCIs important. Principal component analysis (PCA) is a well-known tool to use in multivariate situations. We present, under the assumption of multivariate normality, a new MPCI by applying PCA to a set of suitably transformed variables. We also propose a decision procedure, based on a test of this new index, to be used to decide whether a process can be claimed capable or not at a stated significance level. This new MPCI and its accompanying decision procedure avoid drawbacks found for previously published MPCIs with confidence intervals. By transforming the original variables, we need to consider the first principal component only. Hence, a multivariate situation can be converted into a familiar univariate process capability index. Furthermore, the proposed new MPCI has the property that if the index exceeds a given threshold value the probability of non-conformance is bounded by a known value. Properties, like significance level and power, of the proposed decision procedure is evaluated through a simulation study in the two-dimensional case. A comparative simulation study between our new MPCI and an MPCI previously suggested in the literature is also performed. These studies show that our proposed MPCI with accompanying decision procedure has desirable properties and is worth to study further.

  • 8.
    Andersson Tano, Ingrid
    et al.
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Vännman, Kerstin
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Comparing confidence intervals for multivariate process capability indices2012Inngår i: Quality and Reliability Engineering International, ISSN 0748-8017, E-ISSN 1099-1638, Vol. 28, nr 4, 481-495 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Multivariate process capability indices (MPCIs) are needed for process capability analysis when the quality of a process is determined by several univariate quality characteristics that are correlated. There are several different MPCIs described in the literature, but confidence intervals have been derived for only a handful of these. In practice, the conclusion about process capability must be drawn from a random sample. Hence, confidence intervals or tests for MPCIs are important. With a case study as a start and under the assumption of multivariate normality, we review and compare four different available methods for calculating confidence intervals of MPCIs that generalize the univariate index Cp. Two of the methods are based on the ratio of a tolerance region to a process region, and two are based on the principal component analysis. For two of the methods, we derive approximate confidence intervals, which are easy to calculate and can be used for moderate sample sizes. We discuss issues that need to be solved before the studied methods can be applied more generally in practice. For instance, three of the methods have approximate confidence levels only, but no investigation has been carried out on how good these approximations are. Furthermore, we highlight the problem with the correspondence between the index value and the probability of nonconformance. We also elucidate a major drawback with the existing MPCIs on the basis of the principal component analysis. Our investigation shows the need for more research to obtain an MPCI with confidence interval such that conclusions about the process capability can be drawn at a known confidence level and that a stated value of the MPCI limits the probability of nonconformance in a known way.

  • 9.
    Andersson, Tobias
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Golovlev, Jegor
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Prediktion av bruttoregionalprodukt: Prognosmodellering som förkortar tiden mellan officiella siffror och prognos2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Arbetet har utforskat möjligheten och precisionen av BRP-prediktion för tre statistiska metoder; linjär regression, regressionsträd och modellträd. För modellutvärdering har testfelsskattning erhållen genom korsvalidering och en jämförelse mot Statistiska Centralbyråns (SCB) prognos av BRP används. Resultatet visar att regressionsträd inte lämpar sig för BRP-prediktion, medan de andra två lyckas med rimlig felmarginal. Procentuell avvikelse för metoden som ligger närmast SCB:s prognos har 0,3 i genomsnitt och standardavvikelse 3,0.

  • 10.
    Angelov, Angel G.
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Ekström, Magnus
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Nonparametric estimation for self-selected interval data collected through a two-stage approach2017Inngår i: Metrika (Heidelberg), ISSN 0026-1335, E-ISSN 1435-926X, Vol. 80, nr 4, 377-399 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Self-selected interval data arise in questionnaire surveys when respondents are free to answer with any interval without having pre-specified ranges. This type of data is a special case of interval-censored data in which the assumption of noninformative censoring is violated, and thus the standard methods for interval-censored data (e.g. Turnbull's estimator) are not appropriate because they can produce biased results. Based on a certain sampling scheme, this paper suggests a nonparametric maximum likelihood estimator of the underlying distribution function. The consistency of the estimator is proven under general assumptions, and an iterative procedure for finding the estimate is proposed. The performance of the method is investigated in a simulation study.

  • 11.
    Arvidsson, Dan
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Westerlund, Fredrik
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Fjärranalys av skog med multivariata modeller2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
  • 12.
    Arvidsson, Per
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Snickars, Samuel
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Molekylär klassificering av tjocktarmscancer: PAM-klusteranalys för identifiering av undergrupper2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The main objective of this study is to divide a number of colorectal cancer cases into subgroups based on their molecular features using cluster analysis. The data used is supplied by a research group at Pathology, the Department of Medical Biosciences, Umeå University, and consists, after some preparation, of 455 observations which is a larger data set than many similar studies. The molecular variables that the clustering is based on are CIMP (CpG Island Methylator Phenotype), MSI (Micro Satellite Instability), BRAF- and KRAS-mutations. These are categorical variables and consequently the clustering method used is PAM (Partitioning Around Medoids) which is particularly useful with data on diverse variable level. The final analysis results in four subgroups that are represented by different combinations of attributes on the aforementioned variables. The disparity between the clusters are then evaluated by, for instance, comparing the survival time for their pertaining patients and it appears that two of the clusters are significantly different in this aspect. Other patient related and tumor specific characteristics are also linked with the separate cancer types and tested if they occur in varying extent. The locations of the tumors in the colon are for instance significantly different between the groups. Cluster analyses are exploratory tools so the choice of useful variables and subsequent interpretation of the results can be complicated and require relevant subject knowledge.

  • 13. Asberg, Signild
    et al.
    Eriksson, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Henriksson, Karin M
    Terént, Andreas
    Reduced risk of death with warfarin: results of an observational nationwide study of 20 442 patients with atrial fibrillation and ischaemic stroke2013Inngår i: International Journal of Stroke, ISSN 1747-4930, Vol. 8, nr 8, 689-695 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Warfarin is demonstrated to be superior in efficacy over antiplatelet agents for the prevention of stroke, but the relationship between warfarin and mortality is less clear. Our aim was to investigate this relationship in a large cohort of unselected patients with atrial fibrillation and ischaemic stroke.

    METHODS: This observational study was based on patients who were discharged alive and registered in the Swedish Stroke Register in 2001 through 2005. Vital status was retrieved by linkage to the Swedish Cause of Death Register. We calculated a propensity score for the likelihood of warfarin prescription at discharge from hospital. The risk of death and 95% confidence intervals were estimated in Cox regression models.

    RESULTS: Out of the 20 442 patients with atrial fibrillation and ischaemic stroke (mean age = 79·5 years), 31% (n = 6399) were prescribed warfarin. After adjustment for the propensity score, warfarin was associated with a reduced risk of death (0·67; 95% confidence interval, 0·63-0·71). The crude rate (per 100 person-years) of fatal non-haemorrhagic stroke was lower in patients who received warfarin (1·60; 95% confidence interval, 1·34-1·89) compared to those who received antiplatelet (6·83; 95% confidence interval, 6·42-7·25). The rates (per 100 person-years) of fatal haemorrhagic stroke were 0·21 (95% confidence interval, 0·12-0·32) and 0·43 (95% confidence interval, 0·34-0·55) in patients prescribed warfarin and antiplatelet therapy, respectively.

    CONCLUSIONS: In addition to its established benefit for stroke prevention, warfarin therapy in patients with atrial fibrillation and ischaemic stroke was associated with a reduced risk of death, without an increased risk of fatal haemorrhagic stroke.

  • 14.
    Asplund, Kjell
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Eriksson, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Persson, Olle
    Umeå universitet, Samhällsvetenskapliga fakulteten, Sociologiska institutionen.
    Country comparisons of human stroke research since 2001: a bibliometric study2012Inngår i: Stroke, ISSN 0039-2499, E-ISSN 1524-4628, Vol. 43, nr 3, 830-837 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND AND PURPOSE: This is the first bibliometric comparison between countries of the development of stroke research over time.

    METHODS: Clinical and epidemiological articles on stroke published 2001 to mid-2011 were identified in Science Citation Index Expanded. Article fractions, citation fractions, h-index, and international collaboration were calculated using the BibExcel software and adjusted for population size and gross domestic product.

    RESULTS: The United States dominated with 28.7% of the sum of article fractions and 36.2% of the sum of citation fractions. The United States, Japan, the United Kingdom, and Germany together accounted for 52.1% of articles and 61.0% of citations. When adjusted for population size or gross domestic product, several small European countries, together with Israel and Taiwan, ranked the highest. Per population, there was a negative association (r=0.60) between burden of stroke (disability-adjusted life-years lost) and number of articles per population. In China, South Korea, and Singapore, the annual growth of stroke articles was more than twice the worldwide average. Whereas multinational collaboration was common within Europe and North America, it was relatively uncommon between Asian countries.

    CONCLUSIONS: The Big 4 in scientific literature on stroke, as to both number of articles and citations, are the United States, Japan, the United Kingdom, and Germany. Many small European countries have, in relation to their size, a high scientific production. Several countries with rapidly expanding economies have very fast growth of scientific production on stroke. Our results emphasize the need for stroke research in countries with a high population burden of stroke and they highlight the role of multinational collaboration.

  • 15.
    Backman, Annica
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Sjögren, Karin
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Lindkvist, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik. Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Epidemiologi och global hälsa.
    Lövheim, Hugo
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering.
    Edvardsson, David
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad. School of Nursing and Midwifer y, La Trobe University, Melbourne, VIC, Australia.
    Towards person-centredness in aged-care exploring the  impact of leadership: exploring the  impact of leadership2016Inngår i: Journal of Nursing Management, ISSN 0966-0429, E-ISSN 1365-2834, Vol. 24, nr 6, 766-774 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aim To explore the association between leadership behaviours among managersin aged care, and person-centredness of care and the psychosocial climate. Background Theory suggests that leadership is important for improving person-centredness in aged care, however, empirical evidence is lacking.Methods A cross-sectional design was used to collect data from Swedish agedcare staff (n = 3661). Valid and reliable questionnaires assessing leadershipbehaviours, person-centeredness of care and the psychosocial clima te were used.Data were analysed using multip le linear regression including interaction terms.Results Leadership behaviours were signifi cantly related to the person- centrednessof care and the psychosocial climate. The level of person-centredness of caremoderated the impact of leadership on the psychosocial climate.Conclusions and implications for nursing management The leadership behaviourof managers significantly impacts person-centred care practice and contributes tothe psychosocial climate for both staff and resid ents in aged care. This study isthe first empirically to confirm that middle manage rs have a central leadershiprole in develop ing and supporting person-cent red care practice, thereby creating apositive psychosocial climate and high qua lity care.

  • 16.
    Baranowska-Rataj, Anna
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Sociologiska institutionen.
    De Luna, Xavier
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Ivarsson, Anneli
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Epidemiologi och global hälsa.
    Does the number of siblings affect health in midlife?: Evidence from the Swedish Prescribed Drug Register2016Inngår i: Demographic Research, ISSN 1435-9871, Vol. 35, 1259-1302 s., 43Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: In many societies, growing up in a large family is associated with receiving less parental time, attention, and financial support. As a result, children with a large number of siblings may have worse physical and mental health outcomes than children with fewer siblings.

    Objective: Our objective is to examine the long-term causal effects of sibship size on physical and mental health in modern Sweden.

    Methods: We employ longitudinal data covering the entire Swedish population from the Multigenerational Register and the Medical Birth Register. This data includes information on family size and on potential confounders such as parental background. We use the Prescribed Drug Register to identify the medicines that have been prescribed and dispensed. We use instrumental variable models with multiple births as instruments to examine the causal effects of family size on the health outcomes of children, as measured by receiving medicines at age 45.

    Results: Our results indicate that in Sweden, growing up in a large family does not have a detrimental effect on physical and mental health in midlife.

    Contribution: We provide a systematic overview of the health-related implications of growing up in a large family. We adopt a research design that gives us the opportunity to make causal inferences about the long-term effects of family size. Moreover, our paper provides evidence on the links between family size and health outcomes in the context of a developed country that implements policies oriented towards reducing social inequalities in health and other living conditions.

  • 17.
    Bergman, Jonathan
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Bisphosphonates and the Risk of Fractures: Survival Analysis Using Patient Data from Swedish National Registers2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Background Osteoporosis increases the risk of fractures. Bisphosphonates is a group of medications used to treat osteoporosis. Purpose The purpose of this study was to answer the questions: Do bisphosphonates decrease the risk of fractures? Are the effects ofbisphosphonates different depending on a patient’s age or sex? Methods Data were collected for patients in the Swedish National Patient Register who got a fracture between 2006 and 2012 and who were at least fifty years of age. Kaplan-Meier curves and Cox regression were used; both were extended for time-varying covariates and multiple events. Results A patient who had received a bisphosphonate by any given time had an estimated 45.1 % (hazard ratio, .549; 95 % confidence interval, .524-.574) lower rate of fractures than did a patient who would later receive treatment, given that they were the same age when they entered the study. The effect of bisphosphonate treatment did not vary significantly depending on a patient’s age at study entry (p = .866). A patient’s sex had no significant effect on the rate of fractures after adjusting for his/her age at study entry (p = .142). Discussion It is likely that the patients who received a bisphosphonate suffered osteoporosis to a greater extent than did others. If this had not been taken into account the results would have shown that bisphosphonates were associated with an increased rate of fractures.

  • 18.
    Bergstedt Oscarsson, Kristina
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Infektionssjukdomar.
    Brorstad, Alette
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Infektionssjukdomar.
    Baudin, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Virologi.
    Lindberg, Anne
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Forssén, Annika
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Allmänmedicin.
    Evander, Magnus
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Virologi.
    Eriksson, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Ahlm, Clas
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Infektionssjukdomar.
    Human Puumala hantavirus infection in northern Sweden: increased seroprevalence and association to risk and health factors2016Inngår i: BMC Infectious Diseases, ISSN 1471-2334, E-ISSN 1471-2334, Vol. 16, 566Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: The rodent borne Puumala hantavirus (PUUV) causes haemorrhagic fever with renal syndrome in central and northern Europe. The number of cases has increased and northern Sweden has experienced large outbreaks in 1998 and 2006-2007 which raised questions regarding the level of immunity in the human population.

    METHODS: A randomly selected population aged between 25 and 74 years from northern Sweden were invited during 2009 to participate in a WHO project for monitoring of trends and determinants in cardiovascular disease. Health and risk factors were evaluated and sera from 1,600 participants were available for analysis for specific PUUV IgG antibodies using a recombinant PUUV nucleocapsid protein ELISA.

    RESULTS: The overall seroprevalence in the investigated population was 13.4 %, which is a 50 % increase compared to a similar study only two decades previously. The prevalence of PUUV IgG increased with age, and among 65-75 years it was 22 %. More men (15.3 %) than women (11.4 %) were seropositive (p < 0.05). The identified risk factors were smoking (OR = 1.67), living in rural areas (OR = 1.92), and owning farmland or forest (OR = 2.44). No associations were found between previous PUUV exposure and chronic lung disease, diabetes, hypertension, renal dysfunction, stroke or myocardial infarction.

    CONCLUSIONS: PUUV is a common infection in northern Sweden and there is a high life time risk to acquire PUUV infection in endemic areas. Certain risk factors as living in rural areas and smoking were identified. Groups with increased risk should be targeted for future vaccination when available, and should also be informed about appropriate protection from rodent secreta.

  • 19.
    Berhan, Yonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Eliasson, Mats
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Möllsten, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Waernbaum, Ingeborg
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Dahlquist, Gisela
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Impact of Parental Socioeconomic Status on Excess Mortality in a Population-Based Cohort of Subjects With Childhood-Onset Type 1 Diabetes2015Inngår i: Diabetes Care, ISSN 0149-5992, E-ISSN 1935-5548, Vol. 38, nr 5, 827-832 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: The aim of this study was to analyze the possible impact of parental and individual socioeconomic status (SES) on all-cause mortality in a population-based cohort of patients with childhood-onset type 1 diabetes.

    RESEARCH DESIGN AND METHODS: Subjects recorded in the Swedish Childhood Diabetes Registry (SCDR) from 1 January 1978 to 31 December 2008 were included (n =14,647). The SCDR was linked to the Swedish Cause of Death Registry (CDR) and the Longitudinal Integration Database for Health Insurance and Labour Market Studies (LISA).

    RESULTS: At a mean follow-up of 23.9 years (maximum 46.5 years), 238 deaths occurred in a total of 349,762 person-years at risk. In crude analyses, low maternal education predicted mortality for male patients only (P = 0.046), whereas parental income support predicted mortality in both sexes (P < 0.001 for both). In Cox models stratified by age-at-death group and adjusted for age at onset and sex, parental income support predicted mortality among young adults (≥18 years of age) but not for children. Including the adult patient’s own SES in a Cox model showed that individual income support to the patient predicted mortality occurring at ≥24 years of age when adjusting for age at onset, sex, and parental SES.

    CONCLUSIONS: Exposure to low SES, mirrored by the need for income support, increases mortality risk in patients with childhood-onset type 1 diabetes who died after the age of 18 years.

  • 20.
    Berhan, Yonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Eliasson, Mats
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Möllsten, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Waernbaum, Ingeborg
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Dahlquist, Gisela
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Impact of parental socioeconomic status on excess mortality in subjects with childhood onset type-1 diabetesManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Aims/Hypothesis: The aim of this study was to analyze the possible impact of parental and individual socioeconomic status (SES) on all cause mortality in a population based cohort of childhood onset T1D.

    Methods: Subjects recorded in the Swedish Childhood Diabetes Registry (SCDR) January 1 1978 to December 31 2008 were included (n=14 409). The SCDR was linked to the Swedish Cause of Death Register (CDR) and the Longitudinal Integration Database for Health Insurance and Labour Market Studies (LISA). SES measures (education and income support) wtypeere retrieved from the LISA for the years 1990-2010. Mortality data were retrieved from the CDR as of December 31, 2010.

    Results: At a mean follow-up of 24.4 years (maximum 47.5), 238 deaths occurred in a total of 357 048 person-years at risk. In crude analyses, low maternal education predicted mortality for male cases only (p=0.046), while parental income support predicted mortality in both sexes (p<0.001 for both). In Cox models stratified by age at death groups and adjusted for age at onset and sex, parental income support predicted mortality among young adults ( ≥18 years of age) but not for children. Including the adult patient´s own SES in a Cox model showed that individual income support to the patient predicted mortality occurring at ≥ 24 years of age when adjusting for age at onset, sex and parental SES.

    Conclusions/Interpretation: Low parental SES, mirrored by the need of income support, increases mortality risk in childhood onset type-1 diabetics who died after the age of 18 years.

  • 21.
    Björk, Gustaf
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Tobias, Carlsson
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Klassificeringsmetoder med medicinska tillämpningar: En jämförande studie mellan logistisk regression, elastic net och random forest2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Idag genererar den medicinska forskningen mycket stora mängder data med en skiftande karaktär. Detta har gjort att statistiska klassificeringsmetoder blivit allt mer populära som beslutstöd inom medicinsk forskning och praktik. Den här uppsatsen försöker reda ut om någon av klassificeringsmetoderna logistisk regression, elastic net eller random forest presterar bättre än övriga metoder när datamaterialets förhållande mellan observationer och förklaringsvariabler varierar. Metodernas klassificeringsprestation utvärderas med hjälp av korsvalidering. Resultatet visar att metoderna presterar likvärdigt när datamaterialet består av fler observationer än förklaringsvariabler och även då datamaterialet innehåller fler förklaringsvariabler än observationer. Däremot presterar elastic net klart bättre än de övriga metoderna på det datamaterial där antalet observationer är ungefär lika som antalet förklaringsvariabler. Vidare tyder resultaten på att alla tre metoder med fördel kan användas på datamaterial med fler variabler än observationer vilket är vanligt för datamaterial som rör genetik. Detta givet att en manuell variabelselektion sker för logistisk regression för att metoden ska kunna appliceras i denna situation.

  • 22.
    Björk, Sabine
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Juthberg, Christina
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Lindkvist, Marie
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Epidemiologi och global hälsa. Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wimo, Anders
    Sandman, Per-Olof
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad. Department of Neurobiology, Care Sciences and Society, Division of Nursing, Karolinska Institutet; Department of Health Sciences, Luleå University of Technology.
    Winblad, Bengt
    Edvardsson, David
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad. School of Nursing and Midwifery, La Trobe University.
    Exploring the prevalence and variance of cognitive impairment, pain, neuropsychiatric symptoms and ADL dependency among persons living in nursing homes: a cross-sectional study2016Inngår i: BMC Geriatrics, ISSN 1471-2318, E-ISSN 1471-2318, Vol. 16, 154Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Earlier studies in nursing homes show a high prevalence of cognitive impairment, dependency in activities of daily living (ADL), pain, and neuropsychiatric symptoms among residents. The aim of this study was to explore the prevalence of the above among residents in a nationally representative sample of Swedish nursing homes, and to investigate whether pain and neuropsychiatric symptoms differ in relation to gender, cognitive function, ADL-capacity, type of nursing-home unit and length of stay. Methods: Cross-sectional data from 188 randomly selected nursing homes were collected. A total of 4831 residents were assessed for cognitive and ADL function, pain and neuropsychiatric symptoms. Data were analysed using descriptive statistics and the chi-square test. Results: The results show the following: the prevalence of cognitive impairment was 67 %, 56 % of residents were ADL-dependent, 48 % exhibited pain and 92 % exhibited neuropsychiatric symptoms. The prevalence of pain did not differ significantly between male and female residents, but pain was more prevalent among cognitively impaired and ADL-dependent residents. Pain prevalence was not significantly different between residents in special care units for people with dementia (SCU) and general units, or between shorter-and longer-stay residents. Furthermore, the prevalence of neuropsychiatric symptoms did not differ significantly between male and female residents, between ADL capacities or in relation to length of stay. However, residents with cognitive impairment and residents in SCUs had a significantly higher prevalence of neuropsychiatric symptoms than residents without cognitive impairment and residents in general units. Conclusions: The prevalence rates ascertained in this study could contribute to a greater understanding of the needs of nursing-home residents, and may provide nursing home staff and managers with trustworthy assessment scales and benchmark values for further quality assessment purposes, clinical development work and initiating future nursing assessments.

  • 23.
    Björk, Sabine
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Lindkvist, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik. Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Epidemiologi och global hälsa.
    Wimo, Anders
    Juthberg, Christina
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Bergland, Ådel
    Edvardsson, David
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad. School of Nursing and Midwifery, La Trobe University, Melbourne, Australia.
    Residents' engagement in everyday activities and its association with thriving in nursing homes2017Inngår i: Journal of Advanced Nursing, ISSN 0309-2402, E-ISSN 1365-2648, Vol. 73, nr 8, 1884-1895 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aim: To describe the prevalence of everyday activity engagement for older people in nursing homes and the extent to which engagement in everyday activities is associated with thriving.

    Background: Research into residents’ engagement in everyday activities in nursing homes has focused primarily on associations with quality of life and prevention and management of neuropsychiatric symptoms. However, the mere absence of symptoms does not necessarily guarantee experiences of well-being. The concept of thriving encapsulates and explores experiences of well-being in relation to the place where a person lives.

    Design: A cross-sectional survey.

    Method: A national survey of 172 Swedish nursing homes (2013–2014). Resident (= 4831) symptoms, activities and thriving were assessed by staff using a study survey based on established questionnaires. Descriptive statistics, simple and multiple linear regression, and linear stepwise multiple regression were performed.

    Results: The most commonly occurring everyday activities were receiving hugs and physical touch, talking to relatives/friends and receiving visitors, having conversation with staff not related to care and grooming. The least commonly occurring everyday activities were going to the cinema, participating in an educational program, visiting a restaurant and doing everyday chores. Positive associations were found between activity engagement and thriving, where engagement in an activity program, dressing nicely and spending time with someone the resident likes had the strongest positive association with resident thriving.

    Conclusions: Engagement in everyday activities can support personhood and thriving and can be conceptualized and implemented as nursing interventions to enable residents to thrive in nursing homes.

  • 24.
    Björk, Sabine
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Lövheim, Hugo
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Geriatrik.
    Lindkvist, Marie
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Epidemiologi och global hälsa. Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wimo, Anders
    Edvardsson, David
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad. School of Nursing and Midwifery, La Trobe University, Melbourne, Australia.
    Thriving in relation to cognitive impairment and neuropsychiatric symptoms in Swedish nursing home residents2017Inngår i: International Journal of Geriatric Psychiatry, ISSN 0885-6230, E-ISSN 1099-1166Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objectives: The purpose of this study was to explore relations among thriving, cognitive function, and neuropsychiatric symptoms (NPS) in nursing home residents.

    Methods: A national, cross-sectional, randomized study of Swedish nursing home residents (N = 4831) was conducted between November 2013 and September 2014. Activities of daily life functioning, cognitive functioning, NPS, and thriving were assessed with the Katz activities of daily living, Gottfries' Cognitive Scale, Nursing Home version of the Neuropsychiatric Inventory, and Thriving of Older People Scale, respectively. Individual NPS were explored in relation to cognitive function. Simple linear and multiple regression models were used to explore thriving in relation to resident characteristics.

    Results: Aggression and depressive symptoms were identified as negatively associated with thriving regardless of resident cognitive functioning. At higher levels of cognitive functioning, several factors showed associations with thriving; however, at lower levels of cognitive functioning, only the degree of cognitive impairment and the NPS was associated with thriving. Most of the individual NPS formed nonlinear relationships with cognitive functioning with higher symptom scores in the middle stages of cognitive functioning. Exceptions were elation/euphoria and apathy, which increased linearly with severity of cognitive impairment.

    Conclusions: The lower the cognitive functioning was, the fewer factors were associated with thriving. Aggression and depressive symptoms may indicate lower levels of thriving; thus, targeting these symptoms should be a priority in nursing homes.

  • 25.
    Bohman, Håkan
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Företagsekonomi.
    Bränberg, Kenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Lindberg, Erik
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Företagsekonomi.
    Entrepreneurial education for creating an entrepreneurial mindset2014Inngår i: Education for Sustainable Develplment, 2014, 190-201 s.Konferansepaper (Fagfellevurdert)
  • 26.
    Boraxbekk, Carl-Johan
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Enheten för demografi och åldrandeforskning (CEDAR).
    Lundquist, Anders
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Nordin, Annelie
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Psykiatri.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Nilsson, Lars-Göran
    Aging Research Center, Karolinska Institutet.
    Adolfsson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Psykiatri.
    Free Recall Episodic Memory Performance Predicts Dementia 10 Years Prior to Clinical Diagnosis: Findings from the Betula Longitudinal Study2015Inngår i: Dementia and geriatric cognitive disorders extra, E-ISSN 1664-5464, Vol. 5, nr 2, 191-202 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background/Aims: Early dementia diagnosis is a considerable challenge. The present study examined the predictive value of cognitive performance for a future clinical diagnosis of late-onset Alzheimer's disease or vascular dementia in a random population sample. Methods: Cognitive performance was retrospectively compared between three groups of participants from the Betula longitudinal cohort. Group 1 developed dementia 11-22 years after baseline testing (n = 111) and group 2 after 1-10 years (n = 280); group 3 showed no deterioration towards dementia during the study period (n = 2,855). Multinomial logistic regression analysis was used to investigate the predictive value of tests reflecting episodic memory performance, semantic memory performance, visuospatial ability, and prospective memory performance. Results: Age-and education-corrected performance on two free recall episodic memory tests significantly predicted dementia 10 years prior to clinical diagnosis. Free recall performance also predicted dementia 11-22 years prior to diagnosis when controlling for education, but not when age was added to the model. Conclusion: The present results support the suggestion that two free recall-based tests of episodic memory function may be useful for detecting individuals at risk of developing dementia 10 years prior to clinical diagnosis.

  • 27. Bringman, S.
    et al.
    Holmberg, Henrik
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik. Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin.
    Osterberg, J.
    Location of recurrent groin hernias at TEP after Lichtenstein repair: a study based on the Swedish Hernia Register2016Inngår i: Hernia, ISSN 1265-4906, E-ISSN 1248-9204, Vol. 20, nr 3, 387-391 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To investigate which type of hernia that has the highest risk of a recurrence after a primary Lichtenstein repair. Male patients operated on with a Lichtenstein repair for a primary direct or indirect inguinal hernia and with a TEP for a later recurrence, with both operations recorded in the Swedish Hernia Register (SHR), were included in the study. The study period was 1994-2014. Under the study period, 130,037 male patients with a primary indirect or direct inguinal hernia were operated on with a Lichtenstein repair. A second operation in the SHR was registered in 2236 of these patients (reoperation rate 1.7 %). TEP was the chosen operation in 737 in this latter cohort. The most likely location for a recurrence was the same as the primary location. If the recurrences change location from the primary place, we recognized that direct hernias had a RR of 1.51 to having a recurrent indirect hernia compared to having a direct recurrence after an indirect primary hernia repair. Recurrent hernias after Lichtenstein are more common on the same location as the primary one, compared to changing the location.

  • 28.
    Brink, Mikael
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Reumatologi.
    Hansson, M
    Mathsson-Alm, L
    Wijayatunga, Priyantha
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Verheul, M.K
    Trouw, L.A
    Holmdahl, R
    Rönnelid, J.
    Klareskog, L.
    Rantapää-Dahlqvist, Solbritt
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Reumatologi.
    Rheumatoid Factor Isotypes in Relation to Antibodies Against Citrullinated Peptides and Anti-Carbamylated Antibodies in Individuals Before the Onset of Rheumatoid Arthritis2016Inngår i: Arthritis Research & Therapy, ISSN 1478-6354, E-ISSN 1478-6362, Vol. 18, 43Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: The presence of rheumatoid factor (RF), anti-carbamylated protein antibodies (anti-CarP) and antibodies against citrullinated protein and peptides (ACPA) precedes the onset of symptoms of rheumatoid arthritis (RA) by several years. Relationships between the development of these antibodies are not obvious. 

    Methods: Three isotypes [immunoglobulin A (IgA), IgG and IgM) of RF were analysed in 321 pre-symptomatic individuals who provided 598 samples collected a median of 6.2 (interquartile range 7.2) years before the onset of symptoms, and in 492 population control subjects. All samples were donated to the Biobank of Northern Sweden. RF isotypes were analysed using the EliA system (Phadia GmbH, Freiburg, Germany) with 96 % specificity according to receiver operating characteristic curves. Ten ACPA specificities were analysed using the ImmunoCAP ISAC system, and anti-CCP2 and anti-CarP antibodies were evaluated using enzyme-linked immunosorbent assays. 

    Results: The frequencies of RF isotypes in pre-symptomatic individuals were significantly increased compared with control subjects (p < 0.0001). In samples collected >= 15 years before the onset of symptoms, the IgA-RF isotype was significantly more prevalent than the most frequent ACPAs. Combinations of IgM- and IgA-RF isotypes with ACPA specificities [a-enolase (CEP-1/Eno(5-21))], fibrinogen (Fib)beta(36-52), Fiba(580-600), filaggrin (CCP-1/Fil(307-324)) and anti-CCP2 antibodies were associated with a significantly shorter time to onset of symptoms (p < 0.001-0.05). Using conditional inference tree analysis, anti-CCP2 in combination with anti-filaggrin antibodies gave the highest probability, 97.5 %, for disease development. 

    Conclusions: RF isotypes predicted the development of RA, particularly in combination with ACPA, anti-CCP2 or anti-CarP antibodies. The highest probability for disease development was the presence of anti-CCP2 and anti-filaggrin antibodies.

  • 29.
    Bruce, Elisabeth
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Dorell, Åsa
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Lindh, Viveca
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Erlingsson, Christen
    Lindkvist, Marie
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Epidemiologi och global hälsa. Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Sundin, Karin
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    A translation into Swedish and psychometric analysis of the Icelandic instrument “ICE-Family Perceived Support Questionnaire”, and parents’ estimations of support to families from nursesManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Aims and objectives. Testing the psychometric properties, reliability, and validity of a cross-cultural translation into Swedish of the Icelandic instrument “ICE-Family Perceived Support Questionnaire” and, furthermore, reporting estimations of support given by nurses to families in a sample of parents of children with congenital heart defects.

    Background. Parents of children with congenital heart (CHD) defects often experience greater psychosocial morbidity than parents of children with other medical conditions. In order to design and evaluate interventions with family-centered support, a suitable instrument for measuring family members’ perceived support is required for the Swedish context.

    Design. A translation and psychometric testing of the instrument ICE-FPSQ.

    Methods. A sample of 97 parents, including both fathers and mothers, of children with CHD selected in year 2012. A translation of the ICE-FPSQ into Swedish was done, and reliability and validity were tested for the Swedish version.

    Results. Parents scored low on perceived family support from nurses on the ICE-FPSQ scale. The Swedish version of the ICE-FPSQ was found to be reliable and valid in this context. Reliability was tested by analyzing internal consistency through Cronbach’s α for the entire scale and the two subscales. Test-retest was performed by calculating intra-class correlation, and the results showed satisfactory scale stability over time. The results from the validity test illustrated an acceptable model fit of the Swedish version.

    Conclusion. This study, by psychometrically testing an instrument for Swedish conditions, has provided an instrument for measuring families’ experience of cognitive and emotional support from nurses to families in Sweden. Additionally, the present study found while testing this instrument that nurses at four pediatric cardiac outpatient clinics only sparingly offered family-centered care to the parents.

    Relevance to clinical practice. The Swedish version of ICE-FPSQ can be considered useful to measure the effects of family-centered support interventions in the future. 

  • 30.
    Brännström, Anton
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    En jämförelse mellan likelihoodkvottestet och test baserade på spacings vid förekomst av outliers2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Denna studie jämför styrkefunktionerna mellan det vedertagna likelihoodkvottestet (𝐿𝑇) och test baserade på spacings kallade fidelitytest (𝐹𝑇), under nollhypotesen 𝐻0:𝜃=𝜃0 och den alternativa hypotesen 𝐻𝐴:𝜃≠𝜃0. Tidigare studier har visat att 𝐹𝑇 presterar jämförbara resultat med 𝐿𝑇 under förutsättningar där modellantagandena håller optimalt och där båda testen är applicerbara. FT kan dessutom användas för vissa fall där LT inte fungerar. Syftet med denna uppsats är att med hjälp av simulerade data, undersöka hypotestestens prestation under förhållanden då modellantagandena inte är helt uppfyllda. Mer specifikt undersöker vi fall där observationsmaterialet innehåller avvikande värden, så kallade outliers. Resultaten visar att vissa versioner av 𝐹𝑇 i många fall ger styrkefunktioner som jämfört med LT, håller sig närmare önskad signifikansnivå då 𝜃=𝜃0. För mindre sampelstorlekar visar 𝐹𝑇 fortfarande på en bättre stabilitet, men förlorar i styrka. Det finns även skillnader beroende på vilken version av 𝐹𝑇 vi använder, där vissa har en mer önskvärd stabilitet kring 𝜃=𝜃0 till bekostnad av en lägre styrka och vice versa.

  • 31.
    Brännäs, Kurt
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Laitila, Thomas
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Heteroskedasticity in the Tobit model1989Inngår i: Statistical papers, ISSN 0932-5026, E-ISSN 1613-9798, Vol. 30, nr 1, 185-196 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The paper deals with parameter estimation and the testing of individual parameters in heteroskedastic Tobit models. The statistical properties of semiparametric and maximum likelihood estimators are evaluated. Corresponding t-test statistics are compared. Results from a Monte Carlo experiment indicate that the semiparametric estimator performs relatively better than the maximum likelihood estimator. The associated t-test statistics appear to perform better than the corresponding maximum likelihood test statistics.

  • 32.
    Brännäs, Kurt
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Pohjanpalo, J
    Small sample properties of the likelihood estimator in proportional hazard regression-models with omitted variables1986Inngår i: Biometrical Journal, ISSN 0323-3847, E-ISSN 1521-4036, Vol. 28, nr 2, 219-228 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 33.
    Brännäs, Kurt
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Uhlin, Stig
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Improper use of the ordinary least-squares estimator in the switching regression-model1984Inngår i: Communications in Statistics - Theory and Methods, ISSN 0361-0926, E-ISSN 1532-415X, Vol. 13, nr 14, 1781-1791 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 34.
    Brännäs, Kurt
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Zackrisson, Uno
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    On forecasting of innovations1992Inngår i: Quality and quantity, ISSN 0033-5177, E-ISSN 1573-7845, Vol. 26, nr 1, 95-112 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The forecasting of basic technological innovations is focused. Clarification of the involved key concepts and an analytical framework are given. The forest industry serves as a background and illustration to the discussion. Considerable uncertainty prevails with respect to strategic investments in production in this industry. Industries, technological products, etc. have empirically been shown to pass similar phases of development over time. This life cycle starts with a basic innovation following on a previous invention. Due to competetion from more recent basic innovations the final phase is one of decline. Basic innovations are suggested to be exogenously determined and to cause structural change. The choice of forecasting strategy is suggested to be made dependent on the type of innovation, knowledge base, and life cycle position.

  • 35.
    Bråndal, Anna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin. Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Fysioterapi.
    Eriksson, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Glader, Eva-Lotta
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin.
    Wester, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin.
    Effect of early supported discharge after stroke on patient reported outcome: observational study from the Swedish Riksstroke registryManuskript (preprint) (Annet vitenskapelig)
  • 36.
    Bråndal, Anna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Fysioterapi. Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Eriksson, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wester, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Lundin-Olsson, Lillemor
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Fysioterapi.
    Reliability and validity of the Swedish Fatigue Assessment Scale when self-administrered by persons with mild to moderate stroke2016Inngår i: Topics in Stroke Rehabilitation, ISSN 1074-9357, E-ISSN 1945-5119, Vol. 23, nr 2, 90-97 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective: To examine internal consistency, test-retest reliability, floor/ceiling effects and construct validity of the Fatigue Assessment Scale (FAS), when self-administrated by persons with mild to moderate stroke.

    Method: The FAS was translated into Swedish and tested for psychometric properties when self-administrated by persons with mild to moderate stroke. Participants, consequently selected from the stroke unit admission register received a letter with three questionnaires: the FAS, Short Form Health Survey (SF-36) subscale for vitality and Geriatric Depression Scale, GDS-15. Within two weeks, a second letter with FAS was sent for re-test.

    Result: Seventy-tree persons with mild to moderate stroke participated in the study. Internal consistency was good (Cronbach’s alpha 0.82). The test and retest reliability of individual items showed that five items out of 10 items were good (weighted kappa > 0.60), four were moderate (0.40-0.60), and one was fair (0.22). The relative reliability between total scores was good (ICC 3.1 = 0.73) and the absolute reliability was nine points, meaning that a change of at least nine points in total score implies a real change of fatigue level. Correlation analysis showed that the Swedish FAS correlated with the SF-36 subscale for vitality (rs = - 0.73) and GDS-15 (rs = 0.62), suggesting convergent construct validity. There were no floor or ceiling effects.

    Conclusion: The Swedish translation of the FAS used as a self-administrated questionnaire is reliable and valid for measuring fatigue in persons with mild to moderate stroke.

  • 37.
    Bölenius, Karin
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Lindkvist, Marie
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Epidemiologi och global hälsa. Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Brulin, Christine
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Grankvist, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Nilsson, Karin
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad. Institutionen för omvårdnad i Örnsköldsvik.
    Söderberg, Johan
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Impact of a large-scale educational intervention program on venous blood specimen collection practices2013Inngår i: BMC Health Services Research, ISSN 1472-6963, Vol. 13, nr 1, 463- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Phlebotomy performed with poor adherence to venous blood specimen collection (VBSC) guidelines jeopardizes patient safety and may lead to patient suffering and adverse events. A first questionnaire study demonstrated low compliance to VBSC guidelines, motivating an educational intervention of all phlebotomists within a county council. The aim was to evaluate the impact of a large-scale educational intervention program (EIP) on primary health care phlebotomists' adherence to VBSC guidelines. We hypothesised that the EIP would improve phlebotomists' VBSC practical performance.

    METHODS: The present study comprise primary health care centres (n = 61) from two county councils in northern Sweden. The final selected study group consisted of phlebotomists divided into an intervention group (n = 84) and a corresponding control group (n = 79). Both groups responded to a validated self-reported VBSC questionnaire twice. The EIP included three parts: guideline studies, an oral presentation, and an examination. Non-parametric statistics were used for comparison within and between the groups.

    RESULTS: Evaluating the EIP, we found significant improvements in the intervention group compared to the control group on self-reported questionnaire responses regarding information search (ES = 0.23-0.33, p < 0.001-0.003), and patient rest prior to phlebotomy (ES = 0.27, p = 0.004). Test request management, patient identity control, release of venous stasis, and test tube labelling had significantly improved in the intervention group but did not significantly differ from the control group (ES = 0.22- 0.49, p = < 0.001- 0.006). The control group showed no significant improvements at all (ES = 0--0.39, p = 0.016-0.961).

    CONCLUSIONS: The present study demonstrated several significant improvements on phlebotomists' adherence to VBSC practices. Still, guideline adherence improvement to several crucial phlebotomy practices is needed. We cannot conclude that the improvements are solely due to the EIP and suggest future efforts to improve VBSC. The program should provide time for reflections and discussions. Furthermore, a modular structure would allow directed educational intervention based on the specific VBSC guideline flaws existing at a specific unit. Such an approach is probably more effective at improving and sustaining adherence to VBSC guidelines than an EIP containing general pre-analytical practices.

  • 38. Chaparro, M Pia
    et al.
    de Luna, Xavier
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Häggström, Jenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Ivarsson, Anneli
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Epidemiologi och global hälsa.
    Lindgren, Urban
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för geografi och ekonomisk historia, Kulturgeografi.
    Nilsson, Karina
    Umeå universitet, Samhällsvetenskapliga fakulteten, Sociologiska institutionen.
    Koupil, Ilona
    Childhood family structure and women's adult overweight risk: A longitudinal study2017Inngår i: Scandinavian Journal of Public Health, ISSN 1403-4948, E-ISSN 1651-1905, Vol. 45, nr 5, 511-519 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    AIM: The aim of this study was to investigate whether women's adult overweight and obesity risk was associated with their childhood family structure, measured as their mothers' marital status history, during the women's first 18 years of life.

    METHODS: Using linked register data, we analyzed 30,584 primiparous women born in Sweden in 1975 who were between 19-35 years of age when their height and pre-pregnancy weight was recorded. The outcomes were women's overweight/obesity (body mass index (BMI) ≥ 25 kg/m(2)) and obesity (BMI ≥ 30 kg/m(2)) and the predictor was mothers' marital status history, which was summarized using sequence analysis. We carried out nested logistic regression models adjusting for women's age and maternal sociodemographic characteristics.

    RESULTS: Mothers' marital status history was summarized into six clusters: stable marriage, stable cohabitation, married then divorcing, cohabiting then separating, varied transitions, and not with father. In fully adjusted models and compared with women whose mothers belonged to the stable marriage cluster: (1) women whose mothers belonged to the other marital status clusters had higher odds of overweight/obesity (odds ratio (OR) ranging 1.15-1.19; p < 0.05); and (2) women whose mothers belonged to the stable cohabitation (OR = 1.31; 95% confidence interval (CI) = 1.14-1.52), cohabiting then separating (OR = 1.23; 95% CI = 1.01-1.49), varied transitions (OR = 1.24; 95% CI = 1.11-1.39), and not with father (OR = 1.24; 95% CI = 1.00-1.54) clusters had higher odds of obesity.

    CONCLUSIONS: Women whose mothers were not in stable marriage relationships had higher odds of being overweight or obese in adulthood. The finding that even women raised in the context of stable cohabitation had higher odds of being overweight or obese is intriguing as these relationships are socially accepted in Sweden.

  • 39.
    Chaparro, M Pia
    et al.
    Centre for Health Equity Studies (CHESS).
    Ivarsson, Anneli
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Epidemiologi och global hälsa.
    Koupil, Ilona
    Centre for Health Equity Studies (CHESS).
    Nilsson, Karina
    Umeå universitet, Samhällsvetenskapliga fakulteten, Sociologiska institutionen.
    Häggström, Jenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    de Luna, Xavier
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Lindgren, Urban
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för geografi och ekonomisk historia.
    Regional inequalities in overweight and obesity among first-time pregnant women in Sweden, 1992–20102015Inngår i: 22nd European Congress on Obesity (ECO2015), Prague, Czech Republic, May 6-9, 2015: abstracts, S. Karger, 2015, Vol. 8: suppl 1, 119-119 s.Konferansepaper (Fagfellevurdert)
  • 40.
    Chaparro, M. Pia
    et al.
    Centre for Health Equity Studies (CHESS).
    Ivarsson, Anneli
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Epidemiologi och global hälsa.
    Koupil, Ilona
    Centre for Health Equity Studies (CHESS).
    Nilsson, Karina
    Umeå universitet, Samhällsvetenskapliga fakulteten, Sociologiska institutionen.
    Häggström, Jenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    de Luna, Xavier
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Lindgren, Urban
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för geografi och ekonomisk historia.
    Regional inequalities in pre-pregnancy overweight and obesity in Sweden, 1992, 2000, and 20102015Inngår i: Scandinavian Journal of Public Health, ISSN 1403-4948, E-ISSN 1651-1905, Vol. 43, nr 5, 534-539 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aims: To investigate regional differences and time trends in women’s overweight and obesity in Sweden. Methods: Using datafrom the Swedish Medical Birth Register (women aged ⩾18 years, first pregnancy only) and the Total Population Registeraccessed through the Umeå SIMSAM Lab, age-standardized prevalence of pre-pregnancy overweight/obesity (BMI ⩾ 25 kg/m2) and obesity (BMI ⩾ 30 kg/m2) were estimated by county for the years 1992, 2000, and 2010. Maps were created usingArcMap v10.2.2 to display regional variations over time and logistic regression analyses were used to assess if the observedtrends were significant. Results: The prevalence of pre-pregnancy overweight/obesity and obesity increased significantly inall Swedish counties between 1992, and 2010. In 2010, Södermanland and Gotland exhibited the highest age-standardizedoverweight/obesity (39.7%) and obesity (15.1%) prevalence, respectively. The sharpest increases between 1992 and 2010were observed in Västerbotten for overweight/obesity (75% increase) and in Gotland for obesity (233% increase). Across theyears, Stockholm had the lowest prevalence of overweight/obesity (26.3% in 2010) and obesity (7.3% in 2010) and one ofthe least steep increases in prevalence of both between 1992 and 2010. Conclusions: Substantial regional differencesin pre-pregnancy overweight and obesity prevalence are apparent in Sweden. Further research should elucidatethe mechanisms causing these differences.

  • 41.
    Cipriano, Mariateresa
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Farmakologi.
    Häggström, Jenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Hammarsten, Peter
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Fowler, Christopher J
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Farmakologi.
    Association between cannabinoid CB1 receptor expression and Akt signalling in prostate cancer2013Inngår i: PLoS ONE, ISSN 1932-6203, Vol. 8, nr 6, e65798- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: In prostate cancer, tumour expression of cannabinoid CB1 receptors is associated with a poor prognosis. One explanation for this association comes from experiments with transfected astrocytoma cells, where a high CB receptor expression recruits the Akt signalling survival pathway. In the present study, we have investigated the association between CB1 receptor expression and the Akt pathway in a well-characterised prostate cancer tissue microarray.

    Methodology/Principal Findings: Phosphorylated Akt immunoreactivity (pAkt-IR) scores were available in the database. CB1 receptor immunoreactivity (CB1IR) was rescored from previously published data using the same scale as pAkt-IR. There was a highly significant correlation between CB1IR and pAkt-IR. Further, cases with high expression levels of both biomarkers were much more likely to have a more severe form of the disease at diagnosis than those with low expression levels. The two biomarkers had additive effects, rather than an interaction, upon disease-specific survival.

    Conclusions/Significance: The present study provides data that is consistent with the hypothesis that at a high CB1 receptor expression, the Akt signalling pathway becomes operative.

  • 42.
    Claeson, Anna-Sara
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Gouveia-Figueira, Sandra
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Häggström, Jenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Fowler, Christopher J.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap.
    Nording, Malin L.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Levels of oxylipins, endocannabinoids and related lipids in plasma before and after low-level exposure to acrolein in healthy individuals and individuals with chemical intolerance2017Inngår i: Prostaglandins, Leukotrienes and Essential Fatty Acids, ISSN 0952-3278, E-ISSN 1532-2823, Vol. 121, 60-67 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Oxylipins and endocannabinoids play important biological roles, including effects upon inflammation. It is not known whether the circulating levels of these lipids are affected by inhalation of the environmental pollutant acrolein. In the present study, we have investigated the consequences of low-level exposure to acrolein on oxylipin, endocannabinoid and related lipid levels in the plasma of healthy individuals and individuals with chemical intolerance (CI), an affliction with a suggested inflammatory origin. Participants were exposed twice (60 min) to heptane and a mixture of heptane and acrolein. Blood samples were collected before exposure, after and 24 h post-exposure. There were no overt effects of acrolein exposure on the oxylipin lipidome or endocannibinoids detectable in the bloodstream at the time points investigated. No relationship between basal levels or levels after exposure to acrolein and CI could be identified. This implicates a minor role of inflammatory mediators on the systemic level in CI.

  • 43.
    Claesson Lingehall, Helena
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Smulter, Nina
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap. Cardiothoracic Surgery Division, Heart Center.
    Lindahl, Elisabeth
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Lindkvist, Marie
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin. Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Engström, Karl Gunnar
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Gustavsson, Yngve
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Geriatrik.
    Olofsson, Birgitta
    Umeå universitet, Medicinska fakulteten, Institutionen för omvårdnad.
    Preoperative Cognitive Performance and Postoperative Delirium Are independently Associated With Future Dementia in Older People Who Have Undergone Cardiac Surgery: A Longitudinal Cohort Study2017Inngår i: Critical Care Medicine, ISSN 0090-3493, E-ISSN 1530-0293, Vol. 45, nr 8, 1295-1303 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective: To investigate if postoperative delirium was associated with the development of dementia within 5 years after cardiac surgery.

    Design: Longitudinal cohort study.

    Setting: Cardiothoracic Division, Umeå University Hospital, Sweden.

    Patients: Patients aged 70 years old or older (n = 114) scheduled for routine cardiac procedures with cardiopulmonary bypass without documented dementia were enrolled in 2009.

    Intervention: Structured assessments were performed preoperatively, 1 and 4 days after extubation, and 1, 3, and 5 years postoperatively.

    Measurements and Main Results: Patients were assessed comprehensively, including cognitive and physical function, coexisting medical conditions, demographic characteristics, and medications. Diagnoses of delirium, depression, and dementia were made according to Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision criteria. During the 5-year period, 30 of 114 participants (26.3%) developed dementia. Postoperative delirium had occurred in 87% of those who later developed dementia. A multivariable logistic regression model showed a lower preoperative Mini-Mental State Examination score (p < 0.001; odds ratio, 0.68; 95% CI, 0.54–0.84) and the occurrence of postoperative delirium (p = 0.002; odds ratio, 7.57; 95% CI, 2.15–26.65) were associated with dementia occurrence.

    Conclusions: Our findings suggest that older patients with reduced preoperative cognitive functions or who develop postoperative delirium are at risk of developing dementia within 5 years after cardiac surgery. Cognitive functions should be screened for preoperatively, those who develop postoperative delirium should be followed up to enable early detection of dementia symptoms, and management should be implemented.

  • 44.
    Cremona, Marzia Angela
    et al.
    Penn State University.
    Rebeca, Campos Sanchez
    Penn State University.
    Pini, Alessia
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Vantini, Simone
    Politecnico di Milano.
    Katerina, Makova
    Penn State University.
    Francesca, Chiaromonte
    Penn State University.
    Functional data analysis of omics data: how does the genomic landscape influence integration and fixation of endogenous retroviruses?2017Inngår i: Functional Statistics and Related Fields / [ed] G. Aneiros, E. Bongiorno, R. Cao, P. Vieu, Springer, 2017Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

     We consider thousands of endogenous retrovirus detected in the human

    and mouse genomes, and quantify a large number of genomic landscape features at

    high resolution around their integration sites and in control regions. We propose to

    analyze this data employing a recently developed functional inferential procedure

    and functional logistic regression, with the aim of gaining insights on the effects

    of genomic landscape features on the integration and fixation of endogenous retroviruses.

  • 45.
    de Luna, Xavier
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Discussion of "Perils and potentials of self-selected entry to epidemiological studies and surveys" by N. Keiding and T.A. Louis2016Inngår i: Journal of the Royal Statistical Society: Series A (Statistics in Society), ISSN 0964-1998, E-ISSN 1467-985X, Vol. 179, nr 2, 319-376 s.Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 46.
    de Luna, Xavier
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Fowler, Philip
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Proxy variables and nonparametric identification of causal effectsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Proxy variables are often used in linear regression models with the aim of removing potential confounding bias. In this paper we formalise proxy variables within the potential outcome framework, giving conditions under which it can be shown that causal effects are nonparametrically identified. We characterise two types of proxy variables and give concrete examples where the proxy conditions introduced may hold by design.

  • 47.
    de Luna, Xavier
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Fowler, Philip
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Johansson, Per
    Proxy variables and nonparametric identification of causal effects2017Inngår i: Economics Letters, ISSN 0165-1765, E-ISSN 1873-7374, Vol. 150, 152-154 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Proxy variables are often used in linear regression models with the aim of removing potential confounding bias. In this paper we formalise proxy variables within the potential outcomes framework, giving conditions under which it can be shown that causal effects are nonparametrically identified. We characterise two types of proxy variables and give concrete examples where the proxy conditions introduced may hold by design.

  • 48.
    de Luna, Xavier
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Johansson, Per
    Department of Economics, Uppsala University and Institute of Labour Market Policy Evaluation, Uppsala.
    Erratum to "Non-parametric inference for the effect of a treatment on survival times with application in the health and social sciences" [Journal of Statistical Planning and Inference 140 (7) (July) (2010) 2122–2137]2012Inngår i: Journal of Statistical Planning and Inference, ISSN 0378-3758, Vol. 142, nr 6, 1624-1625 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 49.
    de Luna, Xavier
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Johansson, Per
    Department of Economics, Uppsala University, Uppsala, Sweden; Institute for Evaluation of Labour Market and Education Policy, Uppsala, Sweden.
    Testing for the Unconfoundedness Assumption Using an Instrumental Assumption2014Inngår i: Journal of Causal Inference, ISSN (Online) 2193-3685, (Print) 2193-3677, Vol. 2, nr 2, 187-199 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The identification of average causal effects of a treatment in observational studies is typically based either on the unconfoundedness assumption (exogeneity of the treatment) or on the availability of an instrument. When available, instruments may also be used to test for the unconfoundedness assumption. In this paper, we present a set of assumptions on an instrumental variable which allows us to test for the unconfoundedness assumption, although they do not necessarily yield nonparametric identification of an average causal effect. We propose a test for the unconfoundedness assumption based on the instrumental assumptions introduced and give conditions under which the test has power. We perform a simulation study and apply the results to a case study where the interest lies in evaluating the effect of job practice on employment.

  • 50.
    Degerman, Sofie
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Domellöf, Magdalena
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Landfors, Mattias
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Linder, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Lundin, Mathias
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Haraldsson, Susann
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Elgh, Eva
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Psykiatri.
    Roos, Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Forsgren, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Long Leukocyte Telomere Length at Diagnosis Is a Risk Factor for Dementia Progression in Idiopathic Parkinsonism2014Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, nr 12, e113387Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Telomere length (TL) is regarded as a marker of cellular aging due to the gradual shortening by each cell division, but is influenced by a number of factors including oxidative stress and inflammation. Parkinson's disease and atypical forms of parkinsonism occur mainly in the elderly, with oxidative stress and inflammation in afflicted cells. In this study the relationship between blood TL and prognosis of 168 patients with idiopathic parkinsonism (136 Parkinson's disease [PD], 17 Progressive Supranuclear Palsy [PSP], and 15 Multiple System Atrophy [MSA]) and 30 controls was investigated. TL and motor and cognitive performance were assessed at baseline (diagnosis) and repeatedly up to three to five years follow up. No difference in TL between controls and patients was shown at baseline, nor any significant difference in TL stability or attrition during follow up. Interestingly, a significant relationship between TL at diagnosis and cognitive phenotype at follow up in PD and PSP patients was found, with longer mean TL at diagnosis in patients that developed dementia within three years.

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