Author Contributions: Dr Mattsson had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Hansson, de Leon, Hampel, Wallin, Jönhagen, Minthon, Blennow.
Acquisition of data: Hansson, Andreasen, Parnetti, Jonsson, Herukka, van der Flier, Ewers, Rich, Kaiser, Verbeek, Tsolaki, Mulugeta, Aarsland, Visser, Schröder, Marcusson, Hampel, Scheltens, Pirttilä, Wallin, Jönhagen, Winblad, Blennow.
Analysis and interpretation of data: Mattsson, Zetterberg, Parnetti, Blankenstein, Mulugeta, Rosen, Aarsland, Marcusson, de Leon, Hampel, Wallin, Blennow.
Drafting of the manuscript: Mattsson, Zetterberg, Blennow.
Critical revision of the manuscript for important intellectual content: Hansson, Andreasen, Parnetti, Jonsson, Herukka, van der Flier, Blankenstein, Ewers, Rich, Kaiser, Verbeek, Tsolaki, Mulugeta, Rosen, Aarsland, Visser, Schröder, Marcusson, de Leon, Hampel, Scheltens, Pirttilä, Wallin, Jönhagen, Minthon, Winblad.
Statistical analysis: Mattsson, Rosén.
Obtained funding: Zetterberg, Hansson, Visser, de Leon, Wallin, Jönhagen, Winblad, Blennow
Administrative, technical, or material support: Andreasen, Parnetti, Ewers, Rich, Kaiser, Verbeek, Tsolaki, Mulugeta, Aarsland, Schröder, Marcusson, Winblad, Blennow.
Study supervision: Hanson, Andreasen, Parnetti, Blankenstein, Marcusson, de Leon, Hampel, Scheltens, Pirttilä, Jönhagen, Blennow.
Financial Disclosures: Dr Blennow reports that he has received a consulting fee for an advisory board meeting from Innogenetics. The other authors report no conflicts of interest.
Funding/Support: This study was supported by grants 2006-2740 (Dr Blennow) and 2006-6227 (Dr Zetterberg), from the Swedish Brain Power consortium, the Swedish Research Council (Clinical Neuroproteomics of Neurodegenerative Diseases (cNEUPRO); grant QLK-6-CT-2002-02455 from the European Union, the European Commission Fifth framework programme; the Sahlgrenska University Hospital; the Göteborg Medical Society; Stiftelsen för Gamla Tjänarinnor; the Alzheimer Foundation, Sweden; and the regional agreement on medical training and clinical research (ALF) between Stockholm County Council and the Karolinska Institutet.
Role of the Sponsor: None of the sponsors had any role in design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript.
Additional Contributions: We warmly acknowledge the study participants. Elisabeth Londos, MD, PhD, and Peder Buchhave, MD, at the Clinical Memory Research Unit, Clinical Sciences Malmö, Lund University, Lund, Sweden, contributed in acquisition of data from Malmö, Sweden. Alessia Lanari, MD, and Maria Peducci, MD, at Clinica Neurologica, University of Perugia, Perugia, Italy, contributed in acquisition of data from Perugia, Italy. We thank Åsa Källén, Monica Christiansson, and Sara Hullberg at the Clinical Neurochemistry Laboratory, Mölndal, Sweden, for their skillful technical assistance. No compensation was given for these contributions.