Journal of Alzheimer’s Disease xx (20xx) x–xx DOI 10.3233/JAD-180479 IOS Press 1 Quality of Life in People with Young-Onset Dementia: A Nordic Two-Year Observational Multicenter Study Lara Hvidsten a,b,* , Knut Engedal a,c,d , Geir Selbæk a,e,f , Torgeir Bruun Wyller d,f , J¯ urat˙ e ˘ Saltyt˙ e Benth g,h and Hege Kersten a,i,j a Norwegian National Advisory Unit on Ageing and Health, Vestfold Hospital Trust, Tønsberg, Norway b Division for Mental Health and Addiction, Vestfold Hospital Trust, Tønsberg, Norway c Vestfold Hospital Trust, Tønsberg, Norway d Oslo University Hospital, Department of Geriatric Medicine, Oslo, Norway e The Centre for Old Age Psychiatric Research, Innlandet Hospital Trust, Ottestad, Norway f Faculty of Medicine, University of Oslo, Olso, Norway g Institute of Clinical Medicine, Campus Ahus, University of Oslo, Oslo, Norway h Health Services Research Unit, Akershus University Hospital, Lørenskog, Norway i Pharmaceutical Bioscience, School of Pharmacy, University of Oslo, Oslo, Norway j Department of Research and Development, Telemark Hospital, Skien, Norway Accepted 24 October 2018 Abstract. Background: Cross-sectional studies of quality of life (QOL) of people with young-onset dementia show diverging results. Objective: To identify factors associated with QOL in people with young-onset Alzheimer’s (AD) and frontotemporal dementia (FTD) and explore development in QOL over a two-year period, including differences between the two subtypes. Methods: A two-year cohort study of 88 community-dwelling people with young-onset AD and FTD recruited from Nordic memory clinics. QOL was assessed using the proxy version of the Quality of Life – Alzheimer’s Disease questionnaire, dementia severity was rated with the Clinical Dementia Rating scale, depressive symptoms by the Cornell Scale for Depression in Dementia, awareness with the Reed anosognosia scale, and needs using the Camberwell Assessment of Needs in the Elderly questionnaire. Factors associated with QOL and development in QOL over time were explored with growth mixture model trajectories and mixed model analyses. Results: We identified two groups of people following trajectories with better (n = 35) versus poorer (n = 53) QOL. People with more depressive symptoms at baseline had higher odds of belonging to poorer QOL group, OR 1.2 (CI 1.1; 1.5, p = 0.011). Having Alzheimer’s disease was associated with significantly better QOL (p = 0.047 at baseline, p = 0.009 at T1 and p = 0.033 at T2). Increasing number of unmet needs was significantly associated with poorer QOL at baseline (p = 0.007), but not later in follow-up. Conclusion: Early assessment and treatment based on dementia subtype, depression, and individual needs may enhance quality of life in young-onset dementia. Keywords: Alzheimer’s disease, depression, frontotemporal dementia, quality of life, young-onset * Correspondence to: Lara Hvidsten, Division for Mental Health and Addiction, Vestfold Hospital Trust, P.O. Box 2136, 3103 Tønsberg, Norway. Tel.: +47 33341950/45372654; E-mail: lara.hvidsten@siv.no. ISSN 1387-2877/18/$35.00 © 2018 – IOS Press and the authors. All rights reserved Corrected Proof