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  • 1.
    Backman, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Blomberg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Strandkvist, Viktor
    Department of Health and Technology, Luleå University of Technology, Luleå, Sweden.
    Sawalha, Sami
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Nilsson, Ulf
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Eriksson Ström, Jonas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Hedman, Linnea
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Stridsman, Caroline
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Rönmark, Eva
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Lung function trajectories and associated mortality among adults with and without airway obstruction2023In: American Journal of Respiratory and Critical Care Medicine, ISSN 1073-449X, E-ISSN 1535-4970, Vol. 208, no 10, p. 1063-1074Article in journal (Refereed)
    Abstract [en]

    Rationale: Spirometry is essential for diagnosis and assessment of prognosis in COPD.

    Objectives: To identify FEV1 trajectories and their determinants, based on annual spirometry measurements among individuals with and without airway obstruction. Furthermore, to assess mortality in relation to trajectories.

    Methods: In 2002-04, individuals with airway obstruction (AO) (FEV1/VC<0.70, n=993) and age- and sex-matched non-obstructive (NO) referents were recruited from population-based cohorts. Annual spirometries until 2014 were utilized in joint-survival Latent Class Mixed Models to identify lung function trajectories. Mortality data were collected during 15 years of follow-up.

    Results: Three trajectories were identified among the AO-cases and two among the NO referents. Trajectory membership was driven by baseline FEV1%predicted (%pred) in both groups and additionaly, pack-years in AO and current smoking in NO. Longitudinal FEV1%pred level depended on baseline FEV1%pred, pack-years and obesity. The trajectories were distributed: 79.6% T1AO FEV1-high with normal decline, 12.8% T2AO FEV1-high with rapid decline, and 7.7% T3AO FEV1-low with normal decline (mean 27, 72 and 26 mL/year) among AO-individuals, and 96.7% T1NO FEV1-high with normal decline and 3.3% T2NO FEV1-high with rapid decline (mean 34 and 173 mL/year) among referents. Hazard for death was increased for T2AO (HR1.56) and T3AO (HR3.45) vs. T1AO, and for T2NO (HR2.99) vs. T1NO.

    Conclusions: Three different FEV1 trajectories were identified among those with airway obstruction and two among the referents, with different outcomes in terms of FEV1-decline and mortality. The FEV1 trajectories among airway obstructive and the relationship between low FVC and trajectory outcome are of particular clinical interest.

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  • 2.
    Berglin, Ewa
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Esberg, Anders
    Umeå University, Faculty of Medicine, Department of Odontology.
    Dahlqvist, J.
    Sjowall, J.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Lejon, Kristina
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Johansson, Ingegerd
    Umeå University, Faculty of Medicine, Department of Odontology.
    Mohammad, A. J.
    Rantapää-Dahlqvist, Solbritt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Protein profiling in individuals before onset of anca-associated vasculitis2020In: Annals of the Rheumatic Diseases, ISSN 0003-4967, E-ISSN 1468-2060, Vol. 79, p. 372-372Article in journal (Other academic)
  • 3.
    Boman, Antonia
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Brink, Mikael
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Hansson, Monica
    Mathsson-Alm, Linda
    Rönnelid, Johan
    Berglin, Ewa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Holmdahl, Rikard
    Skriner, Karl
    Serre, Guy
    Klareskog, Lars
    Rantapää-Dahlqvist, Solbritt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Antibodies against citrullinated peptides are associated with clinical and radiological outcomes in patients with early rheumatoid arthritis: a prospective longitudinal inception cohort study2019In: RMD Open, E-ISSN 2056-5933, Vol. 5, no 2, article id e000946Article in journal (Refereed)
    Abstract [en]

    Introduction: Anticitrullinated peptide antibody (ACPA) responses for 22 citrullinated peptides in patients with early rheumatoid arthritis (RA) were analysed and related to radiological and clinical outcome during the first 2 years in a prospective inception cohort.

    Methods: The ACPA reactivities were assessed in 1022 patients with early RA (symptoms <12 months) using the custom-made microarray chip (Thermo Fisher Scientific, Uppsala, Sweden) in a prospective longitudinal study of observational assessments of Disease Activity Score (DAS28 and its components) and radiology during the first 24 months, accounting for the treatment.

    Results: Frequency of ACPA reactivities varied between 13.3% and 63.1%. Of the anticyclic citrullinated peptide-2 (anti-CCP2) antibody-negative patients, ACPA reactivities were positive in 32.6%. Smoking, human leucocyte antigen-shared epitope (HLA-SE), anti-CCP2/rheumatoid factor, protein tyrosine phosphatase non-receptor type 22 (1858C/T) and DAS28 were significantly associated with number of ACPA reactivities. The ACPA reactivities modified differently the development of DAS28 over 24 months (identified using trajectories). Anti-Filaggrin307-324, anti-hnRNP (Peptide)-Z1 and anti-F4-CIT-R antibodies anticipated lower DAS28 values (p<0.01–0.05), while positivity for anti-Fibrinogen(Fib)β62-78(74), and anti-Fibα563-583 predicted higher DAS28 (p<0.01 both). Interaction between anti-Fibß36-52, anti-Pept-5 and anti-Bla-26 antibodies, respectively, and DAS28 during 24 months decreased significantly the DAS28 values (p<0.01–0.05). Corticosteroids and biologicals were related to DAS28-area under the curve and Larsen score 24 months. Anti-vimentin2-17 antibodies remained significantly associated with Larsen score at baseline and 24 months, respectively, and radiological progression, besides biologicals at 24 months adjusted for sex and age.

    Conclusions: Several ACPA reactivities modified significantly the DAS28 development during the first 24 months and were significantly associated with Larsen score at baseline, 24 months and radiological progression.

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  • 4.
    Bondesson, Lennart
    et al.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Traat, Imbi
    Institute of Mathematical Statistics , University of Tartu , Estonia.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Pareto sampling versus Sampford and Conditional Poisson sampling2006In: Scandinavian Journal of Statistics, ISSN 0303-6898, E-ISSN 1467-9469, Vol. 33, no 4, p. 699-720Article in journal (Refereed)
    Abstract [en]

    Pareto sampling was introduced by Rosén in the late 1990s. It is a simple method to get a fixed size πps sample though with inclusion probabilities only approximately as desired. Sampford sampling, introduced by Sampford in 1967, gives the desired inclusion probabilities but it may take time to generate a sample. Using probability functions and Laplace approximations, we show that from a probabilistic point of view these two designs are very close to each other and asymptotically identical. A Sampford sample can rapidly be generated in all situations by letting a Pareto sample pass an acceptance–rejection filter. A new very efficient method to generate conditional Poisson (CP) samples appears as a byproduct. Further, it is shown how the inclusion probabilities of all orders for the Pareto design can be calculated from those of the CP design. A new explicit very accurate approximation of the second-order inclusion probabilities, valid for several designs, is presented and applied to get single sum type variance estimates of the Horvitz–Thompson estimator.

  • 5.
    Boraxbekk, Carl-Johan
    et al.
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nordin, Annelie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Nilsson, Lars-Göran
    Aging Research Center, Karolinska Institutet.
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Free Recall Episodic Memory Performance Predicts Dementia 10 Years Prior to Clinical Diagnosis: Findings from the Betula Longitudinal Study2015In: Dementia and Geriatric Cognitive Disorders Extra, E-ISSN 1664-5464, Vol. 5, no 2, p. 191-202Article in journal (Refereed)
    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.

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  • 6.
    Brink, Mikael
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Berglin, Ewa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Mohammad, Aladdin J.
    Department of Clinical Sciences/Rheumatology, Lund University, Lund, Sweden, and Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Gjertsson, Inger
    Department of Rheumatology and Inflammation Research, Gothenburg University, Gothenburg, Sweden.
    Alexeyenko, Andrey
    Science for Life Laboratory, Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, and Evi-networks, Stockholm, Sweden.
    Lejon, Kristina
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Rantapää-Dahlqvist, Solbritt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Protein profiling in presymptomatic individuals separates myeloperoxidase-antineutrophil cytoplasmic antibody and proteinase 3-antineutrophil cytoplasmic antibody vasculitides2023In: Arthritis & Rheumatology, ISSN 2326-5191, E-ISSN 2326-5205, Vol. 75, no 6, p. 996-1006Article in journal (Refereed)
    Abstract [en]

    Objective: Antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) is a chronic relapsing condition with unknown etiology. To gain insight into the molecular processes underlying the disease, we examined biomarkers in blood samples collected prior to symptom onset.

    Methods: The National Patient Register and Cause of Death register were searched for AAV-related International Classification of Diseases, Ninth Revision and Tenth Revision codes and linked to the registers from 5 biobanks. Eighty-five AAV patients with samples predating symptom onset of AAV were identified. For each case of AAV, 2 matched controls were included. Proteinase 3 (PR3)–ANCA and myeloperoxidase (MPO)–ANCA expression levels were analyzed using enzyme-linked immunosorbent assays. Using an Olink Inflammation panel, 73 of 92 proteins were included after quality control. Data were replicated in a second cohort of 48 presymptomatic individuals and 96 controls.

    Results: Of the 20 proteins with the lowest P values in the original cohort, 7 were replicated in the second cohort and 5 proteins were found to be significant between the groups in a meta-analysis. Eleven different pathways were identified in network enrichment analyses and were found to be significant in both cohorts. Stratification of samples obtained ≤5 years before symptom onset showed significant levels of CCL23, vascular endothelial growth factor A, and hepatocyte growth factor, which were also increased at borderline significant levels in the replication cohort (interleukin-6 was found to be significantly increased in the replication cohort). In presymptomatic AAV patients, 6 proteins were associated with MPO-ANCA positivity, and 7 proteins were associated with PR3-ANCA positivity.

    Conclusion: To our knowledge, this is the first study to identify protein markers preceding symptom onset in AAV patients. These findings set the stage for further research into the underlying cellular and molecular mechanisms in the pathogenesis of AAV and the diversification of patients into PR3-ANCA+ and MPO-ANCA+ subphenotypes. (Figure presented.).

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  • 7.
    Brink, Mikael
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Alexeyenko, Andrey
    Lejon, Kristina
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Rantapää-Dahlqvist, Solbritt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Protein Profiling and Network Enrichment Analysis in Individuals Before and After the Onset of Rheumatoid Arthritis2019In: Arthritis & Rheumatology, ISSN 2326-5191, E-ISSN 2326-5205, Vol. 71Article in journal (Other academic)
  • 8.
    Brink, Mikael
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Alexeyenko, Andrey
    Lejon, Kristina
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Rantapää-Dahlqvist, Solbritt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Protein profiling and network enrichment analysis in individuals before and after the onset of rheumatoid arthritis2019In: Arthritis Research & Therapy, ISSN 1478-6354, E-ISSN 1478-6362, Vol. 21, no 1, article id 288Article in journal (Refereed)
    Abstract [en]

    Background: Antibodies and upregulated cytokines and chemokines predate the onset of rheumatoid arthritis (RA) symptoms. We aimed to identify the pathways related to the early processes leading to RA development, as well as potential novel biomarkers, using multiple protein analyses.

    Methods: A case-control study was conducted within the Biobank of northern Sweden. The plasma samples from 118 pre-symptomatic individuals (207 samples; median predating time 4.1 years), 79 early RA patients, and 74 matched controls were analyzed. The levels of 122 unique proteins with an acknowledged relationship to autoimmunity were analyzed using 153 antibodies and a bead-based multiplex system (FlexMap3D; Luminex Corp.). The data were analyzed using multifactorial linear regression model, random forest, and network enrichment analysis (NEA) based on the 10 most significantly differentially expressed proteins for each two-by-two group comparison, using the MSigDB collection of hallmarks.

    Results: There was a high agreement between the different statistical methods to identify the most significant proteins. The adipogenesis and interferon alpha response hallmarks differentiated pre-symptomatic individuals from controls. These two hallmarks included proteins involved in innate immunity. Between pre-symptomatic individuals and RA patients, three hallmarks were identified as follows: apical junction, epithelial mesenchymal transition, and TGF-beta signaling, including proteins suggestive of cell interaction, remodulation, and fibrosis. The adipogenesis and heme metabolism hallmarks differentiated RA patients from controls.

    Conclusions: We confirm the importance of interferon alpha signaling and lipids in the early phases of RA development. Network enrichment analysis provides a tool for a deeper understanding of molecules involved at different phases of the disease progression.

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  • 9. Davies, G.
    et al.
    Armstrong, N.
    Bis, J. C.
    Bressler, J.
    Chouraki, V.
    Giddaluru, S.
    Hofer, E.
    Ibrahim-Verbaas, C. A.
    Kirin, M.
    Lahti, J.
    van der Lee, S. J.
    Le Hellard, S.
    Liu, T.
    Marioni, R. E.
    Oldmeadow, C.
    Postmus, I.
    Smith, A. V.
    Smith, J. A.
    Thalamuthu, A.
    Thomson, R.
    Vitart, V.
    Wang, J.
    Yu, L.
    Zgaga, L.
    Zhao, W.
    Boxall, R.
    Harris, S. E.
    Hill, W. D.
    Liewald, D. C.
    Luciano, M.
    Adams, H.
    Ames, D.
    Amin, N.
    Amouyel, P.
    Assareh, A. A.
    Au, R.
    Becker, J. T.
    Beiser, A.
    Berr, C.
    Bertram, L.
    Boerwinkle, E.
    Buckley, B. M.
    Campbell, H.
    Corley, J.
    De Jager, P. L.
    Dufouil, C.
    Eriksson, J. G.
    Espeseth, T.
    Faul, J. D.
    Ford, I.
    Gottesman, R. F.
    Griswold, M. E.
    Gudnason, V.
    Harris, T. B.
    Heiss, G.
    Hofman, A.
    Holliday, E. G.
    Huffman, J.
    Kardia, S. L. R.
    Kochan, N.
    Knopman, D. S.
    Kwok, J. B.
    Lambert, J-C
    Lee, T.
    Li, G.
    Li, S-C
    Loitfelder, M.
    Lopez, O. L.
    Lundervold, A. J.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Mather, K. A.
    Mirza, S. S.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Oostra, B. A.
    Palotie, A.
    Papenberg, G.
    Pattie, A.
    Petrovic, K.
    Polasek, O.
    Psaty, B. M.
    Redmond, P.
    Reppermund, S.
    Rotter, J. I.
    Schmidt, H.
    Schuur, M.
    Schofield, P. W.
    Scott, R. J.
    Steen, V. M.
    Stott, D. J.
    Van Swieten, J. C.
    Taylor, K. D.
    Trollor, J.
    Trompet, S.
    Uitterlinden, A. G.
    Weinstein, G.
    Widen, E.
    Windham, B. G.
    Jukema, J. W.
    Wright, A. F.
    Wright, M. J.
    Yang, Q.
    Amieva, H.
    Attia, J. R.
    Bennett, D. A.
    Brodaty, H.
    de Craen, A. J. M.
    Hayward, C.
    Ikram, M. A.
    Lindenberger, U.
    Nilsson, Lars-Göran
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). ARC, Karolinska Institutet, Stockholm.
    Porteous, D. J.
    Raikkonen, K.
    Reinvang, I.
    Rudan, I.
    Sachdev, P. S.
    Schmidt, R.
    Schofield, P. R.
    Srikanth, V.
    Starr, J. M.
    Turner, S. T.
    Weir, D. R.
    Wilson, J. F.
    Van Duijn, C.
    Launer, L.
    Fitzpatrick, A. L.
    Seshadri, S.
    Jr, T. H. Mosley
    Deary, I. J.
    Genetic contributions to variation in general cognitive function: a meta-analysis of genome-wide association studies in the CHARGE consortium (N=53 949)2015In: Molecular Psychiatry, ISSN 1359-4184, E-ISSN 1476-5578, Vol. 20, no 2, p. 183-192Article in journal (Refereed)
    Abstract [en]

    General cognitive function is substantially heritable across the human life course from adolescence to old age. We investigated the genetic contribution to variation in this important, health-and well-being-related trait in middle-aged and older adults. We conducted a meta-analysis of genome-wide association studies of 31 cohorts (N = 53 949) in which the participants had undertaken multiple, diverse cognitive tests. A general cognitive function phenotype was tested for, and created in each cohort by principal component analysis. We report 13 genome-wide significant single-nucleotide polymorphism (SNP) associations in three genomic regions, 6q16.1, 14q12 and 19q13.32 (best SNP and closest gene, respectively: rs10457441, P = 3.93 x 10(-9), MIR2113; rs17522122, P = 2.55 x 10(-8), AKAP6; rs10119, P = 5.67 x 10(-9), APOE/TOMM40). We report one gene-based significant association with the HMGN1 gene located on chromosome 21 (P = 1x10(-6)). These genes have previously been associated with neuropsychiatric phenotypes. Meta-analysis results are consistent with a polygenic model of inheritance. To estimate SNP-based heritability, the genome-wide complex trait analysis procedure was applied to two large cohorts, the Atherosclerosis Risk in Communities Study (N = 6617) and the Health and Retirement Study (N = 5976). The proportion of phenotypic variation accounted for by all genotyped common SNPs was 29% (s.e. = 5%) and 28% (s.e. = 7%), respectively. Using polygenic prediction analysis, similar to 1.2% of the variance in general cognitive function was predicted in the Generation Scotland cohort (N = 5487; P = 1.5 x 10(-17)). In hypothesis-driven tests, there was significant association between general cognitive function and four genes previously associated with Alzheimer's disease: TOMM40, APOE, ABCG1 and MEF2C.

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  • 10. Davies, Gail
    et al.
    Lam, Max
    Harris, Sarah E.
    Trampush, Joey W.
    Luciano, Michelle
    Hill, W. David
    Hagenaars, Saskia P.
    Ritchie, Stuart J.
    Marioni, Riccardo E.
    Fawns-Ritchie, Chloe
    Liewald, David C. M.
    Okely, Judith A.
    Ahola-Olli, Ari V.
    Barnes, Catriona L. K.
    Bertram, Lars
    Bis, Joshua C.
    Burdick, Katherine E.
    Christoforou, Andrea
    DeRosse, Pamela
    Djurovic, Srdjan
    Espeseth, Thomas
    Giakoumaki, Stella
    Giddaluru, Sudheer
    Gustavson, Daniel E.
    Hayward, Caroline
    Hofer, Edith
    Ikram, M. Arfan
    Karlsson, Robert
    Knowles, Emma
    Lahti, Jari
    Leber, Markus
    Li, Shuo
    Mather, Karen A.
    Melle, Ingrid
    Morris, Derek
    Oldmeadow, Christopher
    Palviainen, Teemu
    Payton, Antony
    Pazoki, Raha
    Petrovic, Katja
    Reynolds, Chandra A.
    Sargurupremraj, Muralidharan
    Scholz, Markus
    Smith, Jennifer A.
    Smith, Albert V.
    Terzikhan, Natalie
    Thalamuthu, Anbupalam
    Trompet, Stella
    van der Lee, Sven J.
    Ware, Erin B.
    Windham, B. Gwen
    Wright, Margaret J.
    Yang, Jingyun
    Yu, Jin
    Ames, David
    Amin, Najaf
    Amouyel, Philippe
    Andreassen, Ole A.
    Armstrong, Nicola J.
    Assareh, Amelia A.
    Attia, John R.
    Attix, Deborah
    Avramopoulos, Dimitrios
    Bennett, David A.
    Boehmer, Anne C.
    Boyle, Patricia A.
    Brodaty, Henry
    Campbell, Harry
    Cannon, Tyrone D.
    Cirulli, Elizabeth T.
    Congdon, Eliza
    Conley, Emily Drabant
    Corley, Janie
    Cox, Simon R.
    Dale, Anders M.
    Dehghan, Abbas
    Dick, Danielle
    Dickinson, Dwight
    Eriksson, Johan G.
    Evangelou, Evangelos
    Faul, Jessica D.
    Ford, Ian
    Freimer, Nelson A.
    Gao, He
    Giegling, Ina
    Gillespie, Nathan A.
    Gordon, Scott D.
    Gottesman, Rebecca F.
    Griswold, Michael E.
    Gudnason, Vilmundur
    Harris, Tamara B.
    Hartmann, Annette M.
    Hatzimanolis, Alex
    Heiss, Gerardo
    Holliday, Elizabeth G.
    Joshi, Peter K.
    Kahonen, Mika
    Kardia, Sharon L. R.
    Karlsson, Ida
    Kleineidam, Luca
    Knopman, David S.
    Kochan, Nicole A.
    Konte, Bettina
    Kwok, John B.
    Le Hellard, Stephanie
    Lee, Teresa
    Lehtimaki, Terho
    Li, Shu-Chen
    Liu, Tian
    Koini, Marisa
    London, Edythe
    Longstreth, Will T., Jr.
    Lopez, Oscar L.
    Loukola, Anu
    Luck, Tobias
    Lundervold, Astri J.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lyytikainen, Leo-Pekka
    Martin, Nicholas G.
    Montgomery, Grant W.
    Murray, Alison D.
    Need, Anna C.
    Noordam, Raymond
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Ollier, William
    Papenberg, Goran
    Pattie, Alison
    Polasek, Ozren
    Poldrack, Russell A.
    Psaty, Bruce M.
    Reppermund, Simone
    Riedel-Heller, Steffi G.
    Rose, Richard J.
    Rotter, Jerome I.
    Roussos, Panos
    Rovio, Suvi P.
    Saba, Yasaman
    Sabb, Fred W.
    Sachdev, Perminder S.
    Satizabal, Claudia L.
    Schmid, Matthias
    Scott, Rodney J.
    Scult, Matthew A.
    Simino, Jeannette
    Slagboom, P. Eline
    Smyrnis, Nikolaos
    Soumare, Aicha
    Stefanis, Nikos C.
    Stott, David J.
    Straub, Richard E.
    Sundet, Kjetil
    Taylor, Adele M.
    Taylor, Kent D.
    Tzoulaki, Ioanna
    Tzourio, Christophe
    Uitterlinden, Andre
    Vitart, Veronique
    Voineskos, Aristotle N.
    Kaprio, Jaakko
    Wagner, Michael
    Wagner, Holger
    Weinhold, Leonie
    Wen, K. Hoyan
    Widen, Elisabeth
    Yang, Qiong
    Zhao, Wei
    Adams, Hieab H. H.
    Arking, Dan E.
    Bilder, Robert M.
    Bitsios, Panos
    Boerwinkle, Eric
    Chiba-Falek, Ornit
    Corvin, Aiden
    De Jager, Philip L.
    Debette, Stephanie
    Donohoe, Gary
    Elliott, Paul
    Fitzpatrick, Annette L.
    Gill, Michael
    Glahn, David C.
    Hagg, Sara
    Hansell, Narelle K.
    Hariri, Ahmad R.
    Ikram, M. Kamran
    Jukema, J. Wouter
    Vuoksimaa, Eero
    Keller, Matthew C.
    Kremen, William S.
    Launer, Lenore
    Lindenberger, Ulman
    Palotie, Aarno
    Pedersen, Nancy L.
    Pendleton, Neil
    Porteous, David J.
    Raikkonen, Katri
    Raitakari, Olli T.
    Ramirez, Alfredo
    Reinvang, Ivar
    Rudan, Igor
    Rujescu, Dan
    Schmidt, Reinhold
    Schmidt, Helena
    Schofield, Peter W.
    Schofield, Peter R.
    Starr, John M.
    Steen, Vidar M.
    Trollor, Julian N.
    Turner, Steven T.
    Van Duijn, Cornelia M.
    Villringer, Arno
    Weinberger, Daniel R.
    Weir, David R.
    Wilson, James F.
    Malhotra, Anil
    McIntosh, Andrew M.
    Gale, Catharine R.
    Seshadri, Sudha
    Mosley, Thomas H., Jr.
    Bressler, Jan
    Lencz, Todd
    Deary, Ian J.
    Study of 300,486 individuals identifies 148 independent genetic loci influencing general cognitive function2018In: Nature Communications, E-ISSN 2041-1723, Vol. 9, article id 2098Article in journal (Refereed)
    Abstract [en]

    General cognitive function is a prominent and relatively stable human trait that is associated with many important life outcomes. We combine cognitive and genetic data from the CHARGE and COGENT consortia, and UK Biobank (total N = 300,486; age 16-102) and find 148 genome-wide significant independent loci (P < 5 x 10-8) associated with general cognitive function. Within the novel genetic loci are variants associated with neurodegenerative and neurodevelopmental disorders, physical and psychiatric illnesses, and brain structure. Gene-based analyses find 709 genes associated with general cognitive function. Expression levels across the cortex are associated with general cognitive function. Using polygenic scores, up to 4.3% of variance in general cognitive function is predicted in independent samples. We detect significant genetic overlap between general cognitive function, reaction time, and many health variables including eyesight, hypertension, and longevity. In conclusion we identify novel genetic loci and pathways contributing to the heritability of general cognitive function.

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  • 11.
    Ekman, Urban
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Eriksson, Johan
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Forsgren, Lars
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Domellöf, Magdalena
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Elgh, Eva
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Longitudinal changes in task-evoked brain responses in Parkinson's disease patients with and without mild cognitive impairment2014In: Frontiers in Neuroscience, ISSN 1662-4548, E-ISSN 1662-453X, Vol. 8, article id 207Article in journal (Refereed)
    Abstract [en]

    Cognitive deficits are common in Parkinson's disease. Previous cross-sectional research has demonstrated a link between cognitive impairments and fronto-striatal dopaminergic dysmodulation. However, longitudinal studies that link disease progression with altered task-evoked brain activity are lacking. Therefore, our objective was to longitudinally evaluate working-memory related brain activity changes in Parkinson's disease patients with and without mild cognitive impairment (MCI). Patients were recruited within a longitudinal cohort study of incident patients with idiopathic parkinsonism. We longitudinally (at baseline examination and at 12-months follow-up) compared 28 patients with Parkinson's disease without MCI with 11 patients with Parkinson's disease and MCI. Functional MRI blood oxygen level dependent signal was measured during a verbal two-back working-memory task. Patients with MCI under-recruited bilateral medial prefrontal cortex at both time-points (main effect of group: p < 0.001, uncorrected). Critically, a significant group-by-time interaction effect (p < 0.001, uncorrected) was found in the right fusiform gyrus, indicating that working-memory related activity decreased for patients with Parkinson's disease and MCI between baseline and follow-up, while patients without MCI were stable across time-points. The functional connectivity between right fusiform gyrus and bilateral caudate nucleus was stronger for patients without MCI relative to patients with MCI. Our findings support the view that deficits in working-memory updating are related to persistent fronto-striatal under-recruitments in patients with early phase Parkinson's disease and MCI. The longitudinal evolution of MCI in Parkinson's disease translates into additional task-evoked posterior cortical changes.

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  • 12.
    Eriksson, Staffan
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Gustafson, Yngve
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Lundin-Olsson, Lillemor
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Comparison of three statistical methods for analysis of fall predictors in people with dementia: negative binomial regression (NBR), regression tree (RT), and partial least squares regression (PLSR)2009In: Archives of gerontology and geriatrics (Print), ISSN 0167-4943, E-ISSN 1872-6976, Vol. 49, no 3, p. 383-389Article in journal (Refereed)
    Abstract [en]

    Searching for background factors associated with falls in people with dementia is difficult because the population is heterogeneous. The aim of this study was to compare the efficacies of three statistical methods for analysis of fall predictors in people with dementia. NBR, RT and PLSR analyses were compared. Data used for the comparison were from a prospective cohort study of 192 patients at a psychogeriatric ward, specializing in patients with cognitive impairment and related behavioral and psychological symptoms. Seventy-eight of these patients fell a total of 238 times. PLSR and RT analyses are directed at finding patterns among predictor variables related to outcome, whereas an NBR model is directed at finding predictor variables that, independent of other variables, are related to the outcome. The NBR analysis explained an additional 10–15% variation compared with the PLSR and RT analyses. The results of PLSR and RT show a similar plausible pattern of predictor variables. However, none of these techniques appears to be sufficient in itself. In order to gain patterns of explanatory variables, RT would be a good complement to NBR for analysis of fall predictors.

  • 13. Giddaluru, Sudheer
    et al.
    Espeseth, Thomas
    Salami, Alireza
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Aging Research Center, Karolinska Institutet and Stockholm University, 11330 Stockholm, Sweden.
    Westlye, Lars T
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Christoforou, Andrea
    Cichon, Sven
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Steen, Vidar M
    Reinvang, Ivar
    Nilsson, Lars Göran
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). ARC, Karolinska Institutet, Stockholm, Sweden.
    Le Hellard, Stéphanie
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Genetics of structural connectivity and information processing in the brain2016In: Brain Structure and Function, ISSN 1863-2653, E-ISSN 1863-2661, Vol. 221, no 9, p. 4643-4661Article in journal (Refereed)
    Abstract [en]

    Understanding the genetic factors underlying brain structural connectivity is a major challenge in imaging genetics. Here, we present results from genome-wide association studies (GWASs) of whole-brain white matter (WM) fractional anisotropy (FA), an index of microstructural coherence measured using diffusion tensor imaging. Data from independent GWASs of 355 Swedish and 250 Norwegian healthy adults were integrated by meta-analysis to enhance power. Complementary GWASs on behavioral data reflecting processing speed, which is related to microstructural properties of WM pathways, were performed and integrated with WM FA results via multimodal analysis to identify shared genetic associations. One locus on chromosome 17 (rs145994492) showed genome-wide significant association with WM FA (meta P value = 1.87 × 10(-08)). Suggestive associations (Meta P value <1 × 10(-06)) were observed for 12 loci, including one containing ZFPM2 (lowest meta P value = 7.44 × 10(-08)). This locus was also implicated in multimodal analysis of WM FA and processing speed (lowest Fisher P value = 8.56 × 10(-07)). ZFPM2 is relevant in specification of corticothalamic neurons during brain development. Analysis of SNPs associated with processing speed revealed association with a locus that included SSPO (lowest meta P value = 4.37 × 10(-08)), which has been linked to commissural axon growth. An intergenic SNP (rs183854424) 14 kb downstream of CSMD1, which is implicated in schizophrenia, showed suggestive evidence of association in the WM FA meta-analysis (meta P value = 1.43 × 10(-07)) and the multimodal analysis (Fisher P value = 1 × 10(-07)). These findings provide novel data on the genetics of WM pathways and processing speed, and highlight a role of ZFPM2 and CSMD1 in information processing in the brain.

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  • 14.
    Gomez-Bañuelos, Eduardo
    et al.
    John Hopkins University, Baltimore United states.
    Johansson, Linda
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Konig, Maximilian F.
    John Hopkins University, Baltimore, United States.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Paz, Merlin
    John Hopkins University, Baltimore, United States.
    Buhlin, Kåre
    Karolinska institutet, Stockholm, Sweden.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Odontology.
    Rantapää-Dahlqvist, Solbritt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Andrade, Felipe
    John Hopkins University, Baltimore, United States.
    Exposure to Aggregatibacter Actinomycetemcomitans before Symptom Onset and the Risk of Evolving to Rheumatoid Arthritis2020In: Journal of Clinical Medicine, E-ISSN 2077-0383, Vol. 9, no 6, article id 1906Article in journal (Refereed)
    Abstract [en]

    Periodontal disease has been implicated in the pathogenesis of rheumatoid arthritis (RA), an autoimmune disease characterized by immune-mediated synovial damage, and antibodies to citrullinated antigens. Here, we investigate the association between exposure to the periodontal pathogen Aggregatibacter actinomycetemcomitans (Aa) and the development of RA. IgM, IgG and IgA antibodies to Aa leukotoxin A (LtxA) were detected by ELISA in plasma from a cohort of Swedish adults at different stages of RA development, from before onset of symptoms to established disease. Patients with early and established RA had increased levels of anti-LtxA IgM compared with matched non-RA controls and periodontally healthy individuals. Logistic regression revealed that anti-LtxA IgM levels were associated with RA during early disease (OR 1.012, 95%CI 1.007, 1.017), which was maintained after adjustment for smoking, anti-CCP antibodies, rheumatoid factor, HLA-DRB1 shared epitope alleles and sex. We found no association between anti-LtxA IgG/IgA antibodies and RA at any stage of disease development. The data support a temporal association between anti-LtxA IgM antibodies and the development of RA, suggesting that a subset of RA patients may have been exposed to Aa around the time of transition from being asymptomatic to become a patient with RA.

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  • 15.
    Gorbach, Tetiana
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    de Luna, Xavier
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Salami, Alireza
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM). Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden.
    A Hierarchical Bayesian Mixture Model Approach for Analysis of Resting-State Functional Brain Connectivity: An Alternative to Thresholding2020In: Brain Connectivity, ISSN 2158-0014, E-ISSN 2158-0022, Vol. 10, no 5, p. 202-211Article in journal (Refereed)
    Abstract [en]

    This article proposes a Bayesian hierarchical mixture model to analyze functional brain connectivity where mixture components represent "positively connected" and "non-connected" brain regions. Such an approach provides a data-informed separation of reliable and spurious connections in contrast to arbitrary thresholding of a connectivity matrix. The hierarchical structure of the model allows simultaneous inferences for the entire population as well as for each individual subject. A new connectivity measure, the posterior probability of a given pair of brain regions of a specific subject to be connected given the observed correlation of regions' activity, can be computed from the model fit. The posterior probability reflects the connectivity of a pair of regions relative to the overall connectivity pattern of an individual, which is overlooked in traditional correlation analyses. This article demonstrates that using the posterior probability might diminish the effect of spurious connections on inferences, which is present when a correlation is used as a connectivity measure. In addition, simulation analyses reveal that the sparsification of the connectivity matrix using the posterior probabilities might outperform the absolute thresholding based on correlations. Therefore, we suggest that posterior probability might be a beneficial measure of connectivity compared with the correlation. The applicability of the introduced method is exemplified by a study of functional resting-state brain connectivity in older adults.

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  • 16.
    Gorbach, Tetiana
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    de Luna, Xavier
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Salami, Alireza
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM). Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden; .
    A Hierarchical Bayesian Mixture Modeling Approach for Analysis of Resting-State Functional Brain Connectivity: An Alternative to ThresholdingManuscript (preprint) (Other academic)
  • 17.
    Gorbach, Tetiana
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    de Luna, Xavier
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Salami, Alireza
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM). Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden..
    Bayesian mixture modeling for longitudinal fMRI connectivity studies with dropoutManuscript (preprint) (Other academic)
  • 18.
    Gorbach, Tetiana
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Orädd, Greger
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Josefsson, Maria
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Salami, Alireza
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden.
    de Luna, Xavier
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Longitudinal association between hippocampus atrophy and episodic-memory decline2017In: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 51, p. 167-176Article in journal (Refereed)
    Abstract [en]

    There is marked variability in both onset and rate of episodic-memory decline in aging. Structural magnetic resonance imaging studies have revealed that the extent of age-related brain changes varies markedly across individuals. Past studies of whether regional atrophy accounts for episodic-memory decline in aging have yielded inconclusive findings. Here we related 15-year changes in episodic memory to 4-year changes in cortical and subcortical gray matter volume and in white-matter connectivity and lesions. In addition, changes in word fluency, fluid IQ (Block Design), and processing speed were estimated and related to structural brain changes. Significant negative change over time was observed for all cognitive and brain measures. A robust brain-cognition change-change association was observed for episodic-memory decline and atrophy in the hippocampus. This association was significant for older (65-80 years) but not middle-aged (55-60 years) participants and not sensitive to the assumption of ignorable attrition. Thus, these longitudinal findings highlight medial-temporal lobe system integrity as particularly crucial for maintaining episodic-memory functioning in older age. 

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  • 19. Hagg, S.
    et al.
    Zhan, Y.
    Karlsson, R.
    Gerritsen, L.
    Ploner, A.
    van der Lee, S. J.
    Broer, L.
    Deelen, J.
    Marioni, R. E.
    Wong, A.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Zhu, G.
    Hansell, N. K.
    Sillanpaa, E.
    Fedko, I. O.
    Amin, N. A.
    Beekman, M.
    de Craen, A. J. M.
    Degerman, Sofie
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Harris, S. E.
    Kan, K-J
    Martin-Ruiz, C. M.
    Montgomery, G. W.
    Adolfsson, Annelie N.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Reynolds, C. A.
    Samani, N. J.
    Suchiman, H. E. D.
    Viljanen, A.
    von Zglinicki, T.
    Wright, M. J.
    Hottenga, J-J
    Boomsma, D. I.
    Rantanen, T.
    Kaprio, J. A.
    Nyholt, D. R.
    Martin, N. G.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Kuh, D.
    Starr, J. M.
    Deary, I. J.
    Slagboom, P. E.
    van Duijn, C. M.
    Codd, V.
    Pedersen, N. L.
    Short telomere length is associated with impaired cognitive performance in European ancestry cohorts2017In: Translational Psychiatry, E-ISSN 2158-3188, Vol. 7, article id e1100Article in journal (Refereed)
    Abstract [en]

    The association between telomere length (TL) dynamics on cognitive performance over the life-course is not well understood. This study meta-analyses observational and causal associations between TL and six cognitive traits, with stratifications on APOE genotype, in a Mendelian Randomization (MR) framework. Twelve European cohorts (N = 17 052; mean age = 59.2 +/- 8.8 years) provided results for associations between qPCR-measuredTL (T/S-ratio scale) and general cognitive function, mini-mental state exam (MMSE), processing speed by digit symbol substitution test (DSST), visuospatial functioning, memory and executive functioning (STROOP). In addition, a genetic risk score (GRS) for TL including seven known genetic variants for TL was calculated, and used in associations with cognitive traits as outcomes in all cohorts. Observational analyses showed that longer telomeres were associated with better scores on DSST (beta = 0.051 per s. d.-increase of TL; 95% confidence interval (CI): 0.024, 0.077; P = 0.0002), and MMSE (beta = 0.025; 95% CI: 0.002, 0.047; P = 0.03), and faster STROOP (beta = -0.053; 95% CI: -0.087, -0.018; P = 0.003). Effects for DSST were stronger in APOE epsilon 4 non-carriers (beta = 0.081; 95% CI: 0.045, 0.117; P = 1.0 x 10(-5)), whereas carriers performed better in STROOP (beta = -0.074; 95% CI: -0.140, -0.009; P = 0.03). Causal associations were found for STROOP only (beta = -0.598 per s. d.-increase of TL; 95% CI: -1.125, -0.072; P = 0.026), with a larger effect in epsilon 4-carriers (beta = -0.699; 95% CI: -1.330, -0.069; P = 0.03). Two-sample replication analyses using CHARGE summary statistics showed causal effects between TL and general cognitive function and DSST, but not with STROOP. In conclusion, we suggest causal effects from longer TL on better cognitive performance, where APOE epsilon 4-carriers might be at differential risk.

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  • 20.
    Harrefors, Christina
    et al.
    Institutionen för Hälsovetenskap, Luleå Tekniska Universitet.
    Sävenstedt, Stefan
    Institutionen för Hälsovetenskap, Luleå Tekniska Universitet.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lundquist, Bengt
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Axelsson, Karin
    Institutionen för Hälsovetenskap, Luleå Tekniska Universitet.
    Professional caregivers' perceptions on how persons with mild dementia might experience the usage of a digital photo diary2012In: Open Nursing Journal, E-ISSN 1874-4346, Vol. 6, p. 20-29Article in journal (Refereed)
    Abstract [en]

    Cognitive impairments influence the possibility of persons with dementia to remember daily events and maintain a sense of self. In order to address these problems a digital photo diary was developed to capture information about events in daily life. The device consisted of a wearable digital camera, smart phone with Global Positioning System (GPS) and a home memory station with computer for uploading the photographs and touch screen. The aim of this study was to describe professional caregiver's perceptions on how persons with mild dementia might experience the usage of this digital photo diary from both a situation when wearing the camera and a situation when viewing the uploaded photos, through a questionnaire with 408 respondents. In order to catch the professional caregivers' perceptions a questionnaire with the semantic differential technique was used and the main question was "How do you think Hilda (the fictive person in the questionnaire) feels when she is using the digital photo diary?". The factor analysis revealed three factors; Sense of autonomy, Sense of self-esteem and Sense of trust. An interesting conclusion that can be drawn is that professional caregivers had an overall positive view of the usage of digital photo diary as supporting autonomy for persons with mild dementia. The meaningfulness of each situation when wearing the camera and viewing the uploaded pictures to be used in two different situations and a part of an integrated assistive device has to be considered separately. Individual needs and desires of the person who is living with dementia and the context of each individual has to be reflected on and taken into account before implementing assistive digital devices as a tool in care.

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  • 21.
    Johansson, Jarkko
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Salami, Alireza
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM). Aging Research Center, Karolinska Institutet & Stockholm University, Gavlegatan € 16, S11330, Stockholm, Sweden .
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Longitudinal evidence that reduced hemispheric encoding/retrieval asymmetry predicts episodic-memory impairment in aging2020In: Neuropsychologia, ISSN 0028-3932, E-ISSN 1873-3514, Vol. 137, article id 107329Article in journal (Refereed)
    Abstract [en]

    The HERA (Hemispheric Encoding/Retrieval Asymmetry) model captures hemispheric lateralization of prefrontal cortex (PFC) brain activity during memory encoding and retrieval. Reduced HERA has been observed in cross-sectional aging studies, but there is no longitudinal evidence, to our knowledge, on age-related changes in HERA and whether maintained or reduced HERA relates to well-preserved memory functioning. In the present study we set out to explore HERA in a longitudinal neuroimaging sample from the Betula study [3 Waves over 10 years; Wave-1: n = 363, W2: n = 227, W3: n = 101]. We used fMRI data from a face-name paired-associates task to derive a HERA index. In support of the HERA model, the mean HERA index was positive across the three imaging waves. The longitudinal age-HERA relationship was highly significant (p < 10(-11)), with a HERA decline occurring after age 60. The age-related HERA decline was associated with episodic memory decline (p < 0.05). Taken together, the findings provide large-scale support for the HERA model, and suggest that reduced HERA in the PFC reflects pathological memory aging possibly related to impaired ability to bias mnemonic processing according to the appropriate encoding or retrieval state.

  • 22.
    Jonasson, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Kramer, Arthur
    Departments of Psychology and Mechanical and Industrial Engineering, Northeastern University, Boston, MA, USA.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Riklund, Katrine
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Boraxbekk, Carl-Johan
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital, Hvidovre, Denmark.
    Aerobic Exercise Intervention, CognitivePerformance, and Brain Structure: results from the Physical Influences on Brain in Aging (PHIBRA) Study2017In: Frontiers in Aging Neuroscience, ISSN 1663-4365, E-ISSN 1663-4365, Vol. 8, p. 1-15, article id 336Article in journal (Refereed)
    Abstract [en]

    Studies have shown that aerobic exercise has the potential to improve cognition and reduce brain atrophy in older adults. However, the literature is equivocal with regards to the specificity or generality of these effects. To this end, we report results on cognitive function and brain structure from a 6-month training intervention with 60 sedentary adults (64–78 years) randomized to either aerobic training or stretching and toning control training. Cognitive functions were assessed with a neuropsychological test battery in which cognitive constructs were measured using several different tests. Freesurfer was used to estimate cortical thickness in frontal regions and hippocampus volume. Results showed that aerobic exercisers, compared to controls, exhibited a broad, rather than specific, improvement in cognition as indexed by a higher “Cognitive score,” a composite including episodic memory, processing speed, updating, and executive function tasks (p = 0.01). There were no group differences in cortical thickness, but additional analyses revealed that aerobic fitness at baseline was specifically related to larger thickness in dorsolateral prefrontal cortex (dlPFC), and hippocampus volume was positively associated with increased aerobic fitness over time. Moreover, “Cognitive score” was related to dlPFC thickness at baseline, but changes in “Cognitive score” and dlPFC thickness were associated over time in the aerobic group only. However, aerobic fitness did not predict dlPFC change, despite the improvement in “Cognitive score” in aerobic exercisers. Our interpretation of these observations is that potential exercise-induced changes in thickness are slow, and may be undetectable within 6-months, in contrast to change in hippocampus volume which in fact was predicted by the change in aerobic fitness. To conclude, our results add to a growing literature suggesting that aerobic exercise has a broad influence on cognitive functioning, which may aid in explaining why studies focusing on a narrower range of functions have sometimes reported mixed results.

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  • 23.
    Josefsson, Maria
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Imputation of missing longitudinal fMRI dataManuscript (preprint) (Other academic)
  • 24.
    Karlsson, Maria
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lundin, Mathias
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Student active learning online and in the classroom by combining the best of Flipped Classroom and MOOCs when teaching statistics2017In: RSS International Conference: Abstract booklet, Royal Statistical Society , 2017, p. 18-18Conference paper (Other academic)
    Abstract [en]

    Flipped classroom teaching means, in short, to change/flip where students and teachers dothings. Instead of students (passively) listening to a teacher’s lecture in the classroom andthen going home to solve problems on their own, the idea is that students first watch video lectures at home and then come to the classroom to (actively) solve problems together with other students and the teacher.

    As part of a pedagogical project, we have used special learning management system (LMS)called “Scalable Learning”, which facilitates teaching with flipped classroom techniques. The Scalable Learning LMS allows the teacher to make the video lectures interactive by adding quizzes and surveys to the videos (as is very common in Massive Open Online Courses (MOOCs)), thereby helping the students to be more active while watching the videos. Moreover, there are different tools implemented in the LMS so that students e.g., can ask questions in direct connection to the videos. The student supplied questions and their answers to the quizzes can then, together with other data from the LMS, be used by theteacher to prepare classroom activities customized to the students’ needs.

    We present our experiences of teaching a course in statistics using this LMS; there are both pros and cons from a teachers’ point of view. Also, we present the students’ opinions with the LMS and with the flipped classroom teaching that they were exposed to during the course. Most of them were very satisfied with the concept but they also provided us with several interesting ideas on how to improve the course.

  • 25.
    Kauppi, Karolina
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nilsson, Lars-Göran
    Stockholm University.
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Eriksson, Elias
    Gothenburg University.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Decreased medial temporal lobe activation in BDNF 66Met allele carriers during memory encoding2013In: Neuropsychologia, ISSN 0028-3932, E-ISSN 1873-3514, Vol. 51, no 12, p. 2462-2468Article in journal (Refereed)
    Abstract [en]

    The Met allele of the Brain-derived neurotrophic factor (BDNF) Val(66)Met polymorphism has been associated with impaired activity-dependent secretion of BDNF protein and decreased memory performance. Results from imaging studies relating Val(66)Met to brain activation during memory processing have been inconsistent, with reports of both increased and decreased activation in the Medial Temporal Lobe (MTL) in Met carriers relative to Val homozygotes. Here, we extensively studied BDNF Val(66)Met in relation to brain activation and white matter integrity as well as memory performance in a large imaging (n=194) and behavioral (n=2229) sample, respectively. Functional magnetic resonance imaging (fMRI) was used to investigate MTL activation in healthy participants in the age of 55-75 years during a face-name episodic encoding and retrieval task. White matter integrity was measured using diffusion tensor imaging.

    BDNF Met allele carriers had significantly decreased activation in the MTL during encoding processes, but not during retrieval processes. In contrast to previous proposals, the effect was not modulated by age and the polymorphism was not related to white matter integrity. Met carriers had lower memory performance than Val homozygotes, but differences were subtle and not significant. In conclusion, the BDNF Met allele has a negative influence on MTL functioning, preferentially during encoding processes, which might translate into impaired episodic memory function.

  • 26. Kissel, Theresa
    et al.
    van Schie, Karin Anna
    Hafkenscheid, Lise
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Kokkonen, Heidi
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Wuhrer, Manfred
    Huizinga, Tom W. J.
    Scherer, Hans Ulrich
    Toes, Rene
    Rantapää-Dahlqvist, Solbritt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    On the presence of HLA-SE alleles and ACPA-IgG variable domain glycosylation in the phase preceding the development of rheumatoid arthritis2019In: Annals of the Rheumatic Diseases, ISSN 0003-4967, E-ISSN 1468-2060, Vol. 78, no 12, p. 1616-1620Article in journal (Refereed)
    Abstract [en]

    Objective: Anti-citrullinated protein antibodies (ACPA) in rheumatoid arthritis (RA) patients display a unique feature defined by the abundant presence of N-linked glycans within the variable domains (V-domains). Recently, we showed that N-glycosylation sites, which are required for the incorporation of V-domain glycans, are introduced following somatic hypermutation. However, it is currently unclear when V-domain glycosylation occurs. Further, it is unknown which factors might trigger the generation of V-domain glycans and whether such glycans are relevant for the transition towards RA. Here, we determined the presence of ACPA-IgG V-domain glycans in paired samples of pre-symptomatic individuals and RA patients.

    Methods: ACPA-IgG V-domain glycosylation was analysed using ultra-high performance liquid chromatography (UHPLC) in paired samples of pre-symptomatic individuals (median interquartile range (IQR) pre-dating time: 5.8 (5.9) years; n=201; 139 ACPA-positive and 62 ACPA-negative) and RA patients (n=99; 94 ACPA-positive and 5 ACPA-negative).

    Results: V-domain glycans on ACPA-IgG were already present up to 15 years before disease in pre-symptomatic individuals and their abundance increased closer to symptom onset. Noteworthy, human leucocyte antigen class II shared epitope (HLA-SE) alleles associated with the presence of V-domain glycans on ACPA-IgG.

    Conclusion: Our observations indicate that somatic hypermutation of ACPA, which results in the incorporation of N-linked glycosylation sites and consequently V-domain glycans, occurs already years before symptom onset in individuals that will develop RA later in life. Moreover, our findings provide first evidence that HLA-SE alleles associate with ACPA-IgG V-domain glycosylation in the pre-disease phase and thereby further refine the connection between HLA-SE and the development of ACPA-positive RA.

  • 27. Kissel, Theresa
    et al.
    van Schie, Karin
    Hafkenscheid, Lise
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Scherer, Hans Ulrich
    Kokkonen, Heidi
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Toes, Rene
    Rantapää-Dahlqvist, Solbritt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Rising ACPA igg variable domain glycosylation pre-disease associates with an increase in autoantibody levels and the development of rheumatoid arthritis2019In: Annals of the Rheumatic Diseases, ISSN 0003-4967, E-ISSN 1468-2060, Vol. 78, p. 249-250Article in journal (Other academic)
    Abstract [en]

    Background: Anti-citrullinated protein antibodies (ACPA) are present in the majority of rheumatoid arthritis (RA) patients (60-70%) and play a pivotal role in disease development1. ACPA IgGs are unique in a way that they are abundantly N-glycosylated within their variable regions2. These variable domain (V-domain) glycans are found on over 90% of ACPAs present in sera from RA-patients3. To undergo N-linked glycosylation, a consensus sequence in the protein backbone is required (N-X-S/T, where X ≠ P)4. Recently, it was shown that the N-linked glycosylation sites in ACPA-IgG V-domains are introduced during somatic hypermutation and that the introduction of such sites likely conveys a selective advantage to ACPA expressing B-cells5. However, it is currently unknown, whether ACPA-expressing B-cells already introduced glycosylation-sites into their V-domains before disease onset or when ACPA-V-domain glycosylation occurs.

    Objectives: Investigate the appearance of ACPA V-domain glycosylation in pre-symptomatic individuals and RA patients.

    Methods In a case-control study, individuals (n=201) from the Medical Biobank, who were sampled before onset of symptoms (mean±SEM predating time; 5.8±0.3 years) (140 aCCP+ and 61 aCCP-), and after diagnosis of RA (n=99, 94 aCCP+ and 5 aCCP-) and randomly selected control samples (n=43, 3 aCCP+ and 40 aCCP-) were analyzed for their ACPA IgG V-domain glycosylation levels. ACPA IgGs were affinity purified, N-linked glycans released, and 2-AA labeled for further analysis using UHPLC6. Data calibration and integration was performed and a cut-off defined. Samples below the cut-off were determined as non-detectable and excluded from the analysis. The percentage V-domain glycosylation was calculated as described previously3. Statistical calculations were performed using SPSS.

    Results: Our data indicated that ACPA IgG V-domain glycans are already present years before symptom onset, in pre-symptomatic individuals who subsequently will develop RA. Analysis of matched pairs showed a significant increase of ACPA V-domain glycosylation in RA patients compared to individuals pre-disease (p<0.001). The results showed that ACPA N-glycosylation was correlated with anti-CCP concentrations pre-disease (rs =0.504, p<0.001), while no such association can be found after RA onset. Further, V-domain glycosylation levels increase closer to symptom onset.

  • 28. Kissel, Theresa
    et al.
    Van Wesemael, Tineke J.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Kokkonen, Heidi
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Kawakami, Atsushi
    Tamai, Mami
    Van Schaardenburg, Dirkjan
    Wuhrer, Manfred
    Huizinga, Tom W.J.
    Scherer, Hans Ulrich
    Van Der Woude, Diane
    Rantapää-Dahlqvist, Solbritt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Toes, René E.M.
    Genetic predisposition (HLA-SE) is associated with ACPA-IgG variable domain glycosylation in the predisease phase of RA2021In: Annals of the Rheumatic Diseases, ISSN 0003-4967, E-ISSN 1468-2060, Vol. 16, p. 1-3Article in journal (Refereed)
  • 29.
    Koch, Elise
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Kauppi, Karolina
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Solna, Sweden.
    Polygenic Risk for Schizophrenia Has Sex-Specific Effects on Brain Activity during Memory Processing in Healthy Individuals2022In: Genes, ISSN 2073-4425, E-ISSN 2073-4425, Vol. 13, no 3, article id 412Article in journal (Refereed)
    Abstract [en]

    Genetic risk for schizophrenia has a negative impact on memory and other cognitive abilities in unaffected individuals, and it was recently shown that this effect is specific to males. Using functional MRI, we investigated the effect of a polygenic risk score (PRS) for schizophrenia on brain activation during working memory and episodic memory in 351 unaffected participants (167 males and 184 females, 25–95 years), and specifically tested if any effect of PRS on brain activation is sex-specific. Schizophrenia PRS was significantly associated with decreased brain activation in the left dorsolateral prefrontal cortex (DLPFC) during working-memory manipulation and in the bilateral superior parietal lobule (SPL) during episodic-memory encoding and retrieval. A significant interaction effect between sex and PRS was seen in the bilateral SPL during episodic-memory encoding and retrieval, and sex-stratified analyses showed that the effect of PRS on SPL activation was male-specific. These results confirm previous findings of DLPFC inefficiency in schizophrenia, and highlight the SPL as another important genetic intermediate phenotype of the disease. The observed sex differences suggest that the previously shown male-specific effect of schizophrenia PRS on cognition translates into an additional corresponding effect on brain functioning.

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  • 30.
    Koch, Elise
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Kauppi, Karolina
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Solna, Sweden.
    Sex-specific effects of polygenic risk for schizophrenia on lifespan cognitive functioning in healthy individuals2021In: Translational Psychiatry, E-ISSN 2158-3188, Vol. 11, no 1, article id 520Article in journal (Refereed)
    Abstract [en]

    Polygenic risk for schizophrenia has been associated with lower cognitive ability and age-related cognitive change in healthy individuals. Despite well-established neuropsychological sex differences in schizophrenia patients, genetic studies on sex differences in schizophrenia in relation to cognitive phenotypes are scarce. Here, we investigated whether the effect of a polygenic risk score (PRS) for schizophrenia on childhood, midlife, and late-life cognitive function in healthy individuals is modified by sex, and if PRS is linked to accelerated cognitive decline. Using a longitudinal data set from healthy individuals aged 25–100 years (N = 1459) spanning a 25-year period, we found that PRS was associated with lower cognitive ability (episodic memory, semantic memory, visuospatial ability), but not with accelerated cognitive decline. A significant interaction effect between sex and PRS was seen on cognitive task performance, and sex-stratified analyses showed that the effect of PRS was male-specific. In a sub-sample, we observed a male-specific effect of the PRS on school performance at age 12 (N = 496). Our findings of sex-specific effects of schizophrenia genetics on cognitive functioning across the lifespan indicate that the effects of underlying disease genetics on cognitive functioning is dependent on biological processes that differ between the sexes.

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  • 31.
    Koch, Elise
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Rosenthal, Brin
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Chen, Chi-Hua
    Kauppi, Karolina
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Karolinska Institutet, Department of Medical Epidemiology and Biostatistics, Sweden.
    Interactome overlap between schizophrenia and cognition2020In: Schizophrenia Research, ISSN 0920-9964, E-ISSN 1573-2509, Vol. 222, p. 167-174Article in journal (Refereed)
    Abstract [en]

    Cognitive impairments constitute a core feature of schizophrenia, and a genetic overlap between schizophrenia and cognitive functioning in healthy individuals has been identified. However, due to the high polygenicity and complex genetic architecture of both traits, overlapping biological pathways have not yet been identified between schizophrenia and normal cognitive ability. Network medicine offers a framework to study underlying biological pathways through protein-protein interactions among risk genes. Here, established network-based methods were used to characterize the biological relatedness of schizophrenia and cognition by examining the genetic link between schizophrenia risk genes and genes associated with cognitive performance in healthy individuals, through the protein interactome. First, network separation showed a profound interactome overlap between schizophrenia risk genes and genes associated with cognitive performance (S-AB = -0.22, z-score = -6.80, p= 5.38e-12). To characterize this overlap, network propagation was thereafter used to identify schizophrenia risk genes that are close to cognition-associated genes in the interactome network space (n = 140, of which 54 were part of the direct genetic overlap). Schizophrenia risk genes close to cognition were enriched for pathways including long-termpotentiation and Alzheimer's disease, and included genes with a role in neurotransmitter systems important for cognitive functioning, such as glutamate and dopamine. These results pinpoint a subset of schizophrenia risk genes that are of particular interest for further examination in schizophrenia patient groups, of which some are druggable genes with potential as candidate targets for cognitive enhancing drugs. 

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  • 32.
    Koch, Elise
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Rosenthale, Brin
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Chen, Chi-Hua
    Kauppi, Karolina
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Interactome overlap between schizophrenia and cognition2020In: Schizophrenia Bulletin, ISSN 0586-7614, E-ISSN 1745-1701, Vol. 46, p. S28-S28Article in journal (Other academic)
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  • 33.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    A note on choosing sampling probabilities for conditional Poisson samplingManuscript (Other academic)
    Abstract [en]

    For conditional Poisson sampling the sampling probabilities and the achieved inclusion probabilities are not identical, which is a problem. We present a general method for choosing the sampling probabilities, which uses only the desired inclusion probabilities and transformations of them. We compare the performance of this new method to other reasonable choices of sampling probabilities.

  • 34.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Balanced unequal probability sampling with maximum entropyManuscript (Other academic)
    Abstract [en]

    This paper investigates how to perform balanced unequal probability sampling with maximum entropy. Focus is on balancing conditions having the form of known marginal sums in a cross-stratification table. Since only marginal sums are fixed, the sample sizes for one or more cells in the table are random. The probability distribution for those sample sizes can be expressed explicitly but there are computational difficulties except for very small cases. Markov Chain Monte Carlo methods are proposed for obtaining good distribution approximations, as well as sample selection. Some large-sample Gaussian approximations are also considered. Iterative procedures for obtaining sampling probabilities yielding specified inclusion probabilities are discussed.

  • 35.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Mathematics and Mathematical Statistics.
    Contributions to the theory of unequal probability sampling2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis consists of five papers related to the theory of unequal probability sampling from a finite population. Generally, it is assumed that we wish to make modelassisted inference, i.e. the inclusion probability for each unit in the population is prescribed before the sample is selected. The sample is then selected using some random mechanism, the sampling design. Mostly, the thesis is focused on three particular unequal probability sampling designs, the conditional Poisson (CP-) design, the Sampford design, and the Pareto design. They have different advantages and drawbacks: The CP design is a maximum entropy design but it is difficult to determine sampling parameters which yield prescribed inclusion probabilities, the Sampford design yields prescribed inclusion probabilities but may be hard to sample from, and the Pareto design makes sample selection very easy but it is very difficult to determine sampling parameters which yield prescribed inclusion probabilities. These three designs are compared probabilistically, and found to be close to each other under certain conditions. In particular the Sampford and Pareto designs are probabilistically close to each other. Some effort is devoted to analytically adjusting the CP and Pareto designs so that they yield inclusion probabilities close to the prescribed ones. The result of the adjustments are in general very good. Some iterative procedures are suggested to improve the results even further. Further, balanced unequal probability sampling is considered. In this kind of sampling, samples are given a positive probability of selection only if they satisfy some balancing conditions. The balancing conditions are given by information from auxiliary variables. Most of the attention is devoted to a slightly less general but practically important case. Also in this case the inclusion probabilities are prescribed in advance, making the choice of sampling parameters important. A complication which arises in the context of choosing sampling parameters is that certain probability distributions need to be calculated, and exact calculation turns out to be practically impossible, except for very small cases. It is proposed that Markov Chain Monte Carlo (MCMC) methods are used for obtaining approximations to the relevant probability distributions, and also for sample selection. In general, MCMC methods for sample selection does not occur very frequently in the sampling literature today, making it a fairly novel idea.

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  • 36.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    On the distance between some πps sampling designs2007In: Acta Applicandae Mathematicae - An International Survey Journal on Applying Mathematics and Mathematical Applications, ISSN 0167-8019, E-ISSN 1572-9036, Vol. 97, no 1-3, p. 79-97Article in journal (Refereed)
    Abstract [en]

    Asymptotic distances between probability distributions appearing in πps sampling theory are studied. The distributions are Poisson, Conditional Poisson (CP), Sampford, Pareto, Adjusted CP and Adjusted Pareto sampling. We start with the Kullback-Leibler divergence and the Hellinger distance and derive a simpler distance measure using a Taylor expansion of order two. This measure is evaluated first theoretically and then numerically, using small populations. The numerical examples are also illustrated using a multidimensional scaling technique called principal coordinate analysis (PCO). It turns out that Adjusted CP, Sampford, and adjusted Pareto are quite close to each other. Pareto is a bit further away from these, then comes CP and finally Poisson which is rather far from all the others.

  • 37.
    Lundquist, Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Bondesson, Lennart
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    On sampling with desired inclusion probabilities of first and second order2005Report (Other academic)
    Abstract [en]

    We present a new simple approximation of target probabilities pi for conditional Poisson sampling to obtain given inclusion probabilities. This approximation is based on the fact that the Sampford design gives inclusion probabilities as desired. Some alternative routines to calculate exact pi-values are presented and compared numerically. Further we derive two methods for achieving prescribed 2nd order inclusion probabilities. First we use a probability function belonging to the exponential family. The parameters of this probability function are determined by using an iterative proportional fitting algorithm. Then we modify the conditional Poisson probability function with an additional quadratic factor.

  • 38.
    Lundquist, Anders
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lindberg, Anne
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Eriksson Ström, Jonas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Blomberg, Anders
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Backman, Helena
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health.
    Number of follow-up years needed to identify a rapid decline in FEV12024In: American Journal of Respiratory and Critical Care Medicine, ISSN 1073-449X, E-ISSN 1535-4970, Vol. 209, no 1, p. 119-120Article in journal (Other academic)
  • 39.
    Nyberg, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Kauppi, Karolina
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Persson, Jonas
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Stockholm Brain Institute, Karolinska Institute, Stockholm, Sweden.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Karolinska Institute, Stockholm, Sweden.
    Nilsson, Lars-Göran
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Stockholm University, Stockholm Brain Institute.
    Age-related and genetic modulation of frontal cortex efficiency2014In: Journal of cognitive neuroscience, ISSN 0898-929X, E-ISSN 1530-8898, Vol. 26, no 4, p. 746-754Article in journal (Refereed)
    Abstract [en]

    The dorsolateral pFC (DLPFC) is a key region for working memory. It has been proposed that the DLPFC is dynamically recruited depending on task demands. By this view, high DLPFC recruitment for low-demanding tasks along with weak DLPFC upregulation at higher task demands reflects low efficiency. Here, the fMRI BOLD signal during working memory maintenance and manipulation was examined in relation to aging and catechol-O-methyltransferase (COMT) Val(158)Met status in a large representative sample (n = 287). The efficiency hypothesis predicts a weaker DLPFC response during manipulation, along with a stronger response during maintenance for older adults and COMT Val carriers compared with younger adults and COMT Met carriers. Consistent with the hypothesis, younger adults and met carriers showed maximal DLPFC BOLD response during manipulation, whereas older adults and val carriers displayed elevated DLPFC responses during the less demanding maintenance condition. The observed inverted relations support a link between dopamine and DLPFC efficiency.

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  • 40.
    Nyberg, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Center for Lifespan Changes in Brain and Cognition, University of Oslo, Department of Psychology, University of Oslo, Oslo, Norway.
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Baaré, William F.C.
    Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark.
    Bartrés-Faz, David
    Department of Medicine, Faculty of Medicine and Health Sciences, Institut de Neurociències, Universitat de Barcelona, and Institut d’Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain.
    Bertram, Lars
    Center for Lifespan Changes in Brain and Cognition, University of Oslo, Department of Psychology, University of Oslo, Oslo, Norway; Lübeck Interdisciplinary Platform for Genome Analytics (LIGA), University of Lübeck, Lübeck, Germany.
    Boraxbekk, Carl-Johan
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark; Faculty of Medical and Health Sciences, Institute for Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Neurology, Institute of Sports Medicine Copenhagen (ISMC), Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark.
    Brandmaier, Andreas M.
    Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany; MSB Medical School Berlin, Berlin, Germany; Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Berlin, Germany, and London, UK.
    Demnitz, Naiara
    Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark.
    Drevon, Christian A.
    Vitas AS, Science Park, Oslo, Norway; Department of Nutrition, Faculty of Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
    Duezel, Sandra
    Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.
    Ebmeier, Klaus P.
    Department of Psychiatry, University of Oxford, Oxford, UK.
    Ghisletta, Paolo
    Faculty of Psychology and Educational Sciences, University of Geneva, Geneva, Switzerland; UniDistance Suisse, Brig, Switzerland; Swiss National Centre of Competence in Research LIVES, University of Geneva, Geneva, Switzerland.
    Henson, Richard
    Medical Research Council Cognition and Brain Sciences Unit, Department of Psychiatry, University of Cambridge, Cambridge, England.
    Jensen, Daria E.A.
    5Department of Psychiatry, University of Oxford, Oxford, UK; Wellcome Centre for Integrative Neuroimaging, Oxford Centre for Human Brain Activity, University of Oxford, Oxford, UK.
    Kievit, Rogier A.
    Cognitive Neuroscience Department, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.
    Knights, Ethan
    Medical Research Council Cognition and Brain Sciences Unit, Department of Psychiatry, University of Cambridge, Cambridge, England.
    Kühn, Simone
    Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Berlin, Germany, and London, UK.
    Lindenberger, Ulman
    Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany; Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Berlin, Germany, and London, UK.
    Plachti, Anna
    Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Roe, James M.
    Center for Lifespan Changes in Brain and Cognition, University of Oslo, Department of Psychology, University of Oslo, Oslo, Norway,.
    Madsen, Kathrine Skak
    Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital - Amager and Hvidovre, Copenhagen, Denmark; Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Berlin, Germany, and London, UK.
    Solé-Padullés, Cristina
    Department of Medicine, Faculty of Medicine and Health Sciences, Institut de Neurociències, Universitat de Barcelona, and Institut d’Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain.
    Sommerer, Yasmine
    Lübeck Interdisciplinary Platform for Genome Analytics (LIGA), University of Lübeck, Lübeck, Germany.
    Suri, Sana
    Department of Psychiatry, University of Oxford, Oxford, UK; 1Cognitive Neuroscience Department, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.
    Zsoldos, Enikő
    Department of Psychiatry, University of Oxford, Oxford, UK; 1Cognitive Neuroscience Department, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.
    Fjell, Anders M.
    Center for Lifespan Changes in Brain and Cognition, University of Oslo, Department of Psychology, University of Oslo, Oslo, Norway; Center for Computational Radiology and Artificial Intelligence, Oslo University Hospital, Oslo, Norway.
    Walhovd, Kristine B.
    Center for Lifespan Changes in Brain and Cognition, University of Oslo, Department of Psychology, University of Oslo, Oslo, Norway; Center for Computational Radiology and Artificial Intelligence, Oslo University Hospital, Oslo, Norway.
    Individual differences in brain aging: heterogeneity in cortico-hippocampal but not caudate atrophy rates2023In: Cerebral Cortex, ISSN 1047-3211, E-ISSN 1460-2199, Vol. 33, no 9, p. 5075-5081Article in journal (Refereed)
    Abstract [en]

    It is well documented that some brain regions, such as association cortices, caudate, and hippocampus, are particularly prone to age-related atrophy, but it has been hypothesized that there are individual differences in atrophy profiles. Here, we document heterogeneity in regional-atrophy patterns using latent-profile analysis of 1,482 longitudinal magnetic resonance imaging observations. The results supported a 2-group solution reflecting differences in atrophy rates in cortical regions and hippocampus along with comparable caudate atrophy. The higher-atrophy group had the most marked atrophy in hippocampus and also lower episodic memory, and their normal caudate atrophy rate was accompanied by larger baseline volumes. Our findings support and refine models of heterogeneity in brain aging and suggest distinct mechanisms of atrophy in striatal versus hippocampal-cortical systems.

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  • 41.
    Nyberg, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Salami, Alireza
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM). Aging Research Center, Karolinska Institutet and Stockholm University, Solna, Sweden.
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Frontal Contribution to Hippocampal Hyperactivity During Memory Encoding in Aging2019In: Frontiers in Molecular Neuroscience, ISSN 1662-5099, Vol. 12, article id 229Article in journal (Refereed)
    Abstract [en]

    Hippocampal hypo- as well as hyper-activation have been reported during memory encoding in older individuals. Prefrontal cortex (PFC) provides top-down state signals to the hippocampus that bias its computation during memory encoding and retrieval, and disturbed top-down signals could contribute to hippocampal hyper-activation. Here, we used >500 cross-sectional and longitudinal observations from a face-name encoding-retrieval fMRI task to examine hippocampal hypo-and hyper-activation in aging. Age-related anterior hippocampal hypo-activation was observed during memory encoding. Next, older individuals who longitudinally dropped-out were compared with those who remained in the study. Older dropouts had lower memory performance and higher dementia risk, and hyper-activated right anterior and posterior hippocampus during memory encoding. During encoding, the dropouts also activated right prefrontal regions that instead were active during retrieval in younger and older remainers. Moreover, the dropouts showed altered frontal-hippocampal functional connectivity, notably elevated right PFC to anterior hippocampus (aHC) connectivity during encoding. In the context of a general pattern of age-related anterior hippocampal hypo-activation during encoding, these findings support a top-down contribution to paradoxically high anterior hippocampal activity in older dropouts who were at elevated risk of pathology.

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  • 42.
    Nyberg, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Boraxbekk, Carl-Johan
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Danish Research Centre for Magnetic Resonance (DRCMR), Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Denmark; Institute of Sports Medicine Copenhagen (ISMC), Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark .
    Eriksson Sörman, Daniel
    Hansson, Patrik
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Herlitz, Agneta
    Kauppi, Karolina
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden .
    Ljungberg, Jessica K.
    Lövheim, Hugo
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine. Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM).
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nordin Adolfsson, Annelie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Oudin, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health. Environment Society and Health, Occupational and Environmental Medicine, Lund University.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Rönnlund, Michael
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Stiernstedt, Mikael
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Sundström, Anna
    Umeå University, Faculty of Social Sciences, Department of Psychology. Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Biological and environmental predictors of heterogeneity in neurocognitive ageing: Evidence from Betula and other longitudinal studies2020In: Ageing Research Reviews, ISSN 1568-1637, E-ISSN 1872-9649, Vol. 64, article id 101184Article in journal (Refereed)
    Abstract [en]

    Individual differences in cognitive performance increase with advancing age, reflecting marked cognitive changes in some individuals along with little or no change in others. Genetic and lifestyle factors are assumed to influence cognitive performance in ageing by affecting the magnitude and extent of age-related brain changes (i.e., brain maintenance or atrophy), as well as the ability to recruit compensatory processes. The purpose of this review is to present findings from the Betula study and other longitudinal studies, with a focus on clarifying the role of key biological and environmental factors assumed to underlie individual differences in brain and cognitive ageing. We discuss the vital importance of sampling, analytic methods, consideration of non-ignorable dropout, and related issues for valid conclusions on factors that influence healthy neurocognitive ageing.

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  • 43.
    Nyberg, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). UiO Center for Lifespan Changes in Brain and Cognition, Department of Psychology, University of Oslo, Oslo, Norway.
    Grande, Xenia
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Berron, David
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Stiernstedt, Mikael
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Fjell, Anders
    Walhovd, Kristine
    Orädd, Greger
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Forecasting memory function in aging: pattern-completion ability and hippocampal activity relate to visuospatial functioning over 25 years2020In: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 94, p. 217-226Article in journal (Refereed)
    Abstract [en]

    Heterogeneity in episodic memory functioning in aging was assessed with a pattern-completion functional magnetic resonance imaging task that required reactivation of well-consolidated face-name memory traces from fragmented (partial) or morphed (noisy) face cues. About half of the examined individuals (N = 101) showed impaired (chance) performance on fragmented faces despite intact performance on complete and morphed faces, and they did not show a pattern-completion response in hippocampus or the examined subfields (CA1, CA23, DGCA4). This apparent pattern-completion deficit could not be explained by differential hippocampal atrophy. Instead, the impaired group displayed lower cortical volumes, accelerated reduction in mini-mental state examination scores, and lower general cognitive function as defined by longitudinal measures of visuospatial functioning and speed-of-processing. In the full sample, inter-individual differences in visuospatial functioning predicted performance on fragmented faces and hippocampal CA23 subfield activity over 25 years. These findings suggest that visuospatial functioning in middle age can forecast pattern-completion deficits in aging. 

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  • 44.
    Nyberg, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nordin Adolfsson, Annelie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Zetterberg, Henrik
    Blennow, Kaj
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Elevated plasma neurofilament light in aging reflects brain white-matter alterations but does not predict cognitive decline or Alzheimer's disease2020In: Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring (DADM), ISSN 2352-8729, Vol. 12, no 1, article id e12050Article in journal (Refereed)
    Abstract [en]

    Introduction: We investigated neurofilament light (NFL) accumulation in normal aging as well as in preclinical and clinical Alzheimer's disease (AD) and assessed individual differences in NFL load in relation to cognition and brain white-matter integrity.

    Methods: We analyzed longitudinal data covering 30 years (1988-2017). Cognitive testing was done up to six times. Plasma NFL was quantified for controls and 142 cases who developed AD over time, and longitudinal changes in NFL were quantified for 100 individuals with three brain-imaging sessions.

    Results: Longitudinal analyses revealed age-related NFL increases with marked variability. AD cases had elevated NFL levels, while no significant group differences were seen in the preclinical phase. Variability in NFL levels showed non-significant correlations with cognition but was associated with brain white matter.

    Discussion: Our findings suggest that elevated blood NFL, likely reflecting brain white-matter alterations, characterizes clinical AD, while NFL levels do not predict age-related cognitive impairment or impending AD.

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  • 45.
    Nyberg, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Center for Lifespan Changes in Brain and Cognition, University of Oslo, Oslo, Norway.
    Magnussen, Fredrik
    Center for Lifespan Changes in Brain and Cognition, University of Oslo, Oslo, Norway.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Baaré, William
    Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark.
    Bartrés-Faz, David
    Department of Medicine, Faculty of Medicine and Health Sciences and Neurosciences Institute, University of Barcelona, Barcelona, Spain.
    Bertram, Lars
    Center for Lifespan Changes in Brain and Cognition, University of Oslo, Oslo, Norway; Lübeck Interdisciplinary Platform for Genome Analytics, University of Lübeck, Lübeck, Germany.
    Boraxbekk, Carl-Johan
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark; Institute of Sports Medicine Copenhagen, Copenhagen University Hospital, Bispebjerg, Copenhagen, Denmark.
    Brandmaier, Andreas M.
    Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany; Max Planck University College London Centre for Computational Psychiatry and Ageing Research, Berlin, Germany.
    Drevon, Christian A.
    Vitas AS, Research Park, Oslo, Norway; Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, Medicine/University of Oslo, Oslo, Norway.
    Ebmeier, Klaus
    Warneford Hospital, University of Oxford, Oxford, United Kingdom.
    Ghisletta, Paolo
    Faculté de Psychologie et des Sciences de l'Education, Université de Genève, Geneva, Switzerland.
    Henson, Richard N.
    Medical Research Council Cognition and Brain Sciences Unit, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom.
    Junqué, Carme
    Department of Medicine, Faculty of Medicine and Health Sciences and Neurosciences Institute, University of Barcelona, Barcelona, Spain.
    Kievit, Rogier
    Medical Research Council Cognition and Brain Sciences Unit, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Cognitive Neuroscience Department, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands.
    Kleemeyer, Maike
    Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany.
    Knights, Ethan
    Medical Research Council Cognition and Brain Sciences Unit, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom.
    Kühn, Simone
    Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany; Department of Psychiatry and Psychotherapy, University Clinic Hamburg-Eppendorf, Hamburg, Germany.
    Lindenberger, Ulman
    Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany; Max Planck University College London Centre for Computational Psychiatry and Ageing Research, Berlin, Germany.
    Penninx, Brenda W.J.H.
    Department of Psychiatry, Amsterdam University Medical Center, Vrije Universiteit, Amsterdam, Netherlands.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Sørensen, Øystein
    Center for Lifespan Changes in Brain and Cognition, University of Oslo, Oslo, Norway.
    Vaqué-Alcázar, Lídia
    Department of Medicine, Faculty of Medicine and Health Sciences and Neurosciences Institute, University of Barcelona, Barcelona, Spain.
    Walhovd, Kristine B.
    Center for Lifespan Changes in Brain and Cognition, University of Oslo, Oslo, Norway; Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
    Fjell, Anders M.
    Center for Lifespan Changes in Brain and Cognition, University of Oslo, Oslo, Norway; Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
    Educational attainment does not influence brain aging2021In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 118, no 18, article id 2101644118Article in journal (Refereed)
    Abstract [en]

    Education has been related to various advantageous lifetime outcomes. Here, using longitudinal structural MRI data (4,422 observations), we tested the influential hypothesis that higher education translates into slower rates of brain aging. Cross-sectionally, education was modestly associated with regional cortical volume. However, despite marked mean atrophy in the cortex and hippocampus, education did not influence rates of change. The results were replicated across two independent samples. Our findings challenge the view that higher education slows brain aging.

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  • 46.
    Nyberg, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Structural and functional imaging of aging: longitudinal sudies2017In: Cognitive neuroscience of aging: linking cognitive and cerebral aging / [ed] Roberto Cabeza, Lars Nyberg, and Denise C. Park, New York: Oxford University Press, 2017, 2, p. 155-182Chapter in book (Refereed)
    Abstract [en]

    This chapter on longitudinal structural and functional brain imaging examines points of convergence and divergence in findings from neuroimaging studies using cross-sectional versus longitudinal designs. Representative longitudinal age gradients are identified. It presents key methodological issues in longitudinal imaging, including test-retest effects, the influence of attrition, and different kinds of missing data. Various ways of handling data missingness in statistical analyses are also discussed.

  • 47.
    Pohl, Petra
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Ahlgren, Christina
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Nordin, Ellinor
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lundin-Olsson, Lillemor
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Gender perspective on fear of falling using the classification of functioning as the model2015In: Disability and Rehabilitation, ISSN 0963-8288, E-ISSN 1464-5165, Vol. 37, no 3, p. 214-222Article in journal (Refereed)
    Abstract [en]

    Abstract Purpose: To investigate associations between fear of falling (FOF) and recurrent falls among women and men, and gender differences in FOF with respect to International Classification of Functioning (ICF). Methods: Community-dwelling people (n = 230, 75-93 years, 72% women) were included and followed 1 year regarding falls. Data collection included self-reported demographics, questionnaires, and physical performance-based tests. FOF was assessed with the question "Are you afraid of falling?". Results were discussed with a gender relational approach. Results: At baseline 55% women (n = 92) and 22% men (n = 14) reported FOF. During the follow-up 21% women (n = 35) and 30% men (n = 19) experienced recurrent falls. There was an association between gender and FOF (p = 0.001), but not between FOF and recurrent falls (p = 0.79), or between gender and recurrent falls (p = 0.32). FOF was related to Personal factors and Activity and Participation. The relationship between FOF and Personal factors was in opposite directions for women and men. Conclusions: Results did not support the prevailing paradigm that FOF increases rate of recurrent falls in community-dwelling people, and indicated that the answer to "Are you afraid of falling?" might be highly influenced by gendered patterns.

    Implications for Rehabilitation

    The question "Are you afraid of falling?" has no predictive value when screening for the risk of falling in independent community-dwelling women or men over 75 years of age.

    Gendered patterns might influence the answer to the question "Are you afraid of falling?" Healthcare personnel are recommended to be aware of this when asking older women and men about fear of falling.

  • 48.
    Pohl, Petra
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Nordin, Ellinor
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Bergström, Ulrica
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Lundin-Olsson, Lillemor
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Community-dwelling older people with an injurious fall are likely to sustain new injurious falls within 5 years: a prospective long-term follow-up study2014In: BMC Geriatrics, ISSN 1471-2318, E-ISSN 1471-2318, Vol. 14, no 1, p. 120-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Fall-related injuries in older people are a leading cause of morbidity and mortality. Self-reported fall events in the last year is often used to estimate fall risk in older people. However, it remains to be investigated if the fall frequency and the consequences of the falls have an impact on the risk for subsequent injurious falls in the long term. The objective of this study was to investigate if a history of one single non-injurious fall, at least two non-injurious falls, or at least one injurious fall within 12 months increases the risk of sustaining future injurious falls.

    METHODS: Community-dwelling individuals 75-93 years of age (n = 230) were initially followed prospectively with monthly calendars reporting falls over a period of 12 months. The participants were classified into four groups based on the number and type of falls (0, 1, ≥2 non-injurious falls, and ≥1 injurious fall severe enough to cause a visit to a hospital emergency department). The participants were then followed for several years (mean time 5.0 years ±1.1) regarding injurious falls requiring a visit to the emergency department. The Andersen-Gill method of Cox regression for multiple events was used to estimate the risk of injurious falls.

    RESULTS: During the long-term follow-up period, thirty per cent of the participants suffered from at least one injurious fall. Those with a self-reported history of at least one injurious fall during the initial 12 months follow-up period showed a significantly higher risk for sustaining subsequent injurious falls in the long term (hazard ratio 2.78; 95% CI, 1.40-5.50) compared to those with no falls. No other group showed an increased risk.

    CONCLUSIONS: In community-dwelling people over 75 years of age, a history of at least one self-reported injurious fall severe enough to cause a visit to the emergency department within a period of 12 months implies an increased risk of sustaining future injurious falls. Our results support the recommendations to offer a multifactorial fall-risk assessment coupled with adequate interventions to community-dwelling people over 75 years who present to the ED due to an injurious fall.

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  • 49.
    Salami, Alireza
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM). Aging Research Center, Karolinska Institute, Stockholm, Sweden.
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Blennow, Kaj
    Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nordin Adolfsson, Annelie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Schöll, Michael
    Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden; Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, United Kingdom.
    Zetterberg, Henrik
    Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden; Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, United Kingdom; UK Dementia Research Institute at UCL, London, United Kingdom.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM).
    Association of APOE ɛ4 and Plasma p-tau181 with Preclinical Alzheimer's Disease and Longitudinal Change in Hippocampus Function2022In: Journal of Alzheimer's Disease, ISSN 1387-2877, E-ISSN 1875-8908, Vol. 85, no 3, p. 1309-1320Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The Apolipoprotein E (APOE) ɛ4 allele has been linked to increased tau phosphorylation and tangle formation. APOE ɛ4 carriers with elevated tau might be at the higher risk for Alzheimer's disease (AD) progression. Previous studies showed that tau pathology begins early in areas of the medial temporal lobe. Similarly, APOE ɛ4 carriers showed altered hippocampal functional integrity. However, it remains unknown whether the influence of elevated tau accumulation on hippocampal functional changes would be more pronounced for APOE ɛ4 carriers.

    OBJECTIVE: We related ɛ4 carriage to levels of plasma phosphorylated tau (p-tau181) up to 15 years prior to AD onset. Furthermore, elevated p-tau181 was explored in relation to longitudinal changes in hippocampal function and connectivity.

    METHODS: Plasma p-tau181 was analyzed in 142 clinically defined AD cases and 126 matched controls. The longitudinal analysis involved 87 non-demented individuals (from population-based study) with two waves of plasma samples and three waves of functional magnetic resonance imaging during rest and memory encoding.

    RESULTS: Increased p-tau181 was observed for both ɛ4 carriers and non-carriers close to AD onset, but exclusively for ɛ4 carriers in the early preclinical groups (7- and 13-years pre-AD). In ɛ4 carriers, longitudinal p-tau181 increase was paralleled by elevated local hippocampal connectivity at rest and subsequent reduction of hippocampus encoding-related activity.

    CONCLUSION: Our findings support an association of APOE ɛ4 and p-tau181 with preclinical AD and hippocampus functioning.

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  • 50.
    Salami, Alireza
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Aging Research Center, Karolinska Institutet and Stockholm University, SE-113 30, Stockholm, Sweden.
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Kaboodvand, Neda
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Aging Research Center, Karolinska Institutet and Stockholm University, SE-113 30, Stockholm, Sweden.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Longitudinal Evidence for Dissociation of Anterior and Posterior MTL Resting-State Connectivity in Aging: Links to Perfusion and Memory2016In: Cerebral Cortex, ISSN 1047-3211, E-ISSN 1460-2199, Vol. 26, no 10, p. 3953-3963Article in journal (Refereed)
    Abstract [en]

    Neuroimaging studies of spontaneous signal fluctuations as measured by resting-state functional magnetic resonance imaging have revealed age-related alterations in the functional architecture of brain networks. One such network is located in the medial temporal lobe (MTL), showing structural and functional variations along the anterior-posterior axis. Past cross-sectional studies of MTL functional connectivity (FC) have yielded discrepant findings, likely reflecting the fact that specific MTL subregions are differentially affected in aging. Here, using longitudinal resting-state data from 198 participants, we investigated 5-year changes in FC of the anterior and posterior MTL. We found an opposite pattern, such that the degree of FC within the anterior MTL declined after age 60, whereas elevated FC within the posterior MTL was observed along with attenuated posterior MTL-cortical connectivity. A significant negative change-change relation was observed between episodic-memory decline and elevated FC in the posterior MTL. Additional analyses revealed age-related cerebral blood flow (CBF) increases in posterior MTL at the follow-up session, along with a positive relation of elevated FC and CBF, suggesting that elevated FC is a metabolically demanding alteration. Collectively, our findings indicate that elevated FC in posterior MTL along with increased local perfusion is a sign of brain aging that underlie episodic-memory decline.

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