Protocol of the Cognitive Health in Ageing Register: Investigational, Observational and Trial Studies in Dementia Research (CHARIOT): Prospective Readiness cOhort (PRO) SubStudy
Authors: Udeh-Momoh Chinedu T. , Watermeyer Tamlyn , Price Geraint , de Jager Loots Celeste A , Reglinska-Matveyev Natalia , Ropacki Michael , Ketter Nzeera , Fogle Michael , Raghavan Nandini , Arrighi Michael , Brashear Robert , Di Jianing , Baker Susan , Giannakopoulou Parthenia , Robb Catherine , Bassil Darina , Cohn Martin , McLellan-Young Heather , Crispin Jennifier , Lakey Kristina , Lisa Curry , Chowdary Seemulamoodi Yellappa , Kafetsouli Dimitra , Perera Dinithi , Car Josip , Majeed Azeem , Ward Heather , Ritchie Karen , Perneczky Robert , Kivipelto Miia , Scott David , Bracoud Luc , Saad Ziad , Novak Gerald , Ritchie Craig W , Middleton Lefkos 
Published: June 2021

IntroductionThe Cognitive Health in Ageing Register: Investigational, Observational and Trial Studies in Dementia Research (CHARIOT): Prospective Readiness cOhort (PRO) SubStudy (CPSS), sponsored by Janssen Pharmaceutical Research & Development LLC, is an Alzheimer’s disease (AD) biomarker enriched observational study that began 3 July 2015 CPSS aims to identify and validate determinants of AD, alongside cognitive, functional and biological changes in older adults with or without detectable evidence of AD pathology at baseline.Methods and analysisCPSS is a dual-site longitudinal cohort (3.5 years) assessed quarterly. Cognitively normal participants (60–85 years) were recruited across Greater London and Edinburgh. Participants are classified as high, medium (amnestic or non-amnestic) or low risk for developing mild cognitive impairment–Alzheimer’s disease based on their Repeatable Battery for the Assessment of Neuropsychological Status performance at screening. Additional AD-related assessments include: a novel cognitive composite, the Global Preclinical Alzheimer’s Cognitive Composite, brain MRI and positron emission tomography and cerebrospinal fluid analysis. Lifestyle, other cognitive and functional data, as well as biosamples (blood, urine, and saliva) are collected. Primarily, study analyses will evaluate longitudinal change in cognitive and functional outcomes. Annual interim analyses for descriptive data occur throughout the course of the study, although inferential statistics are conducted as required.Ethics and disseminationCPSS received ethical approvals from the London—Central Research Ethics Committee (15/LO/0711) and the Administration of Radioactive Substances Advisory Committee (RPC 630/3764/33110) The study is at the forefront of global AD prevention efforts, with frequent and robust sampling of the well-characterised cohort, allowing for detection of incipient pathophysiological, cognitive and functional changes that could inform therapeutic strategies to prevent and/or delay cognitive impairment and dementia. Dissemination of results will target the scientific community, research participants, volunteer community, public, industry, regulatory authorities and policymakers. On study completion, and following a predetermined embargo period, CPSS data are planned to be made accessible for analysis to facilitate further research into the determinants of AD pathology, onset of symptomatology and progression.Trial registration numberThe CHARIOT:PRO SubStudy is registered with clinicaltrials.gov (NCT02114372). Notices of protocol modifications will be made available through this trial registry.