The PREVENT Dementia programme: Baseline demographic, lifestyle, imaging and cognitive data from a midlife cohort study investigating risk factors for dementia

PREVENT is a multi-centre prospective cohort study in the UK and Ireland that aims to examine mid-life risk factors for dementia, identify and describe the earliest indices of disease development. The PREVENT dementia programme is one of the original epidemiological initiatives targeting midlife as a critical window for intervention in neurodegenerative conditions. This paper provides an overview of the study protocol and presents the first summary results from the initial baseline data to describe the cohort. Participants in the PREVENT cohort provide demographic data, biological samples (blood, saliva, urine and optional cerebrospinal fluid), lifestyle and psychological questionnaires, undergo a comprehensive cognitive test battery, and are imaged using multi-modal 3T magnetic resonance imaging (MRI) scanning, with both structural and functional sequences. The PREVENT cohort governance structure is described, which includes a steering committee, a scientific advisory board and core patient and public involvement groups. A number of sub-studies which supplement the main PREVENT cohort are also described. The PREVENT cohort baseline data includes 700 participants recruited between 2014 and 2020 across five sites in the UK and Ireland (Cambridge, Dublin, Edinburgh, London and Oxford). At baseline, participants had a mean age of 51.2 years (range 40-59, SD ±5.47), with the majority female (n=433, 61.9%). There was a near equal distribution of participants with and without a parental history of dementia (51.4% vs 48.6%) and a relatively high prevalence of APOE⍰4 carriers (n=264, 38.0%). Participants were highly educated (16.7 ± 3.44 years of education), were mainly of European Ancestry (n=672, 95.9%) and were cognitively healthy as measured by the Addenbrookes Cognitive Examination-III (ACE-III) (Total score 95.6 ±4.06). Mean white matter hyperintensity (WMH) volume at recruitment was 2.26 ± 2.77 ml (median = 1.39ml), with hippocampal volume 8.15 ± 0.79ml. There was good representation of known dementia risk factors in the cohort. The PREVENT cohort offers a novel dataset to explore midlife risk factors and early signs of neurodegenerative disease. Data are available open access at no cost via the Alzheimer’s Disease Data Initiative (ADDI) platform and Dementia Platforms UK (DPUK) platform pending approval of the data access request from the PREVENT steering group committee. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement PREVENT is funded by the Alzheimers Society (grant numbers 178, 264 and 329), Alzheimers Association (grant number TriBEKa-17-519007) and philanthropic donations. Sub-studies have their own funding sources which are not detailed here. GMT acknowledges the support of the Osteopathic Heritage Foundation through funding for the Osteopathic Heritage Foundation Ralph S. Licklider, D.O., Research Endowment in the Heritage College of Osteopathic Medicine. IK declares support for the work on this project through the Oxford Health Biomedical Research Centre, Medical Research Council Dementias Platform UK project as well as personal awards (NIHR Academic Lectureship and NIHR Development and Skills Enhancement award). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Multi-site ethical approval was granted by the UK London-Camberwell St Giles National Health Service (NHS) Research Ethics Committee (REC reference: 12/LO/1023, IRAS project ID: 88938), which operates according to the Helsinki Declaration of 1975 (and as revised in 1983). A separate ethical application for Ireland was submitted for the Dublin site, was reviewed and given a favourable opinion by Trinity College Dublin School of Psychology Research Ethics Committee (SPREC022021-010) and the St James Hospital/Tallaght University Hospital Joint Research Ethics Committee. All substantial protocol amendments have been reviewed by the same ethics committees and favourable opinion was granted before implementation at sites. All sub-studies referred to have individual ethical applications and favourable opinions. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The baseline dataset is available to access through a data request on the study website ([www.preventdementia.co.uk][1]); on the Alzheimer’s Disease Data Initiative (ADDI) platform baseline dataset DOI: [https://doi.org/10.34688/PREVENTMAIN\_BASELINE\_700V1][2]; Dementia Platforms UK (DPUK); and the Global Alzheimer’s Association Network (GAAIN). For imaging data a number of derived variables (for example the global volumetrics and WMH volume) are available in the ADDI dataset, with raw structural data available to access upon request following defacing. [1]: http://www.preventdementia.co.uk [2]: https://doi.org/10.34688/PREVENTMAIN_BASELINE_700V1