Objective The Eating Disorders Genetics Initiative United Kingdom (EDGI UK), part of the National Institute for Health and Care Research (NIHR) Mental Health BioResource, aims to deepen our understanding of the environmental and genetic aetiology of eating disorders. EDGI UK launched in February 2020 and is partnered with the UK eating disorders charity, Beat. There are multiple EDGI branches worldwide. Method EDGI UK recruits via media and clinical services. Anyone living in England, at least 16 years old, with a lifetime probable or clinical eating disorder is eligible to sign up online: edgiuk.org. Participants complete online questionnaires, donate a saliva sample for genetic analysis, and consent to medical record linkage and recontact for future studies. Results As of September 2022, EDGI UK has recruited 8,397 survey participants: 98% female, 93% white, 97.7% cisgender, 67% heterosexual, and 52% have a university degree. Half (51.7%) of participants have returned their saliva kit. The most common diagnoses are anorexia nervosa (42.7%), atypical anorexia nervosa (31.4%), bulimia nervosa (33.2%), binge-eating disorder (14.6%), and purging disorder (33.5%). Conclusion EDGI UK is the largest UK eating disorders study but needs to increase its diversity, and efforts are underway to do so. It also offers a unique opportunity to accelerate eating disorder research, and collaboration between researchers and participants with lived experience, with unparalleled sample size.

Prof Breen has received honoraria, research or conference grants and consulting fees from Illumina, Otsuka, and COMPASS Pathfinder Ltd. Prof Hotopf is principal investigator of the RADAR-CNS consortium, an IMI public private partnership, and as such receives research funding from Janssen, UCB, Biogen, Lundbeck and MSD

This work was supported by the National Institute for Health and Care Research (NIHR) BioResource [RG94028, RG85445], NIHR Biomedical Research Centre [IS-BRC-1215-20018]. Helena Davies and Alicia Peel acknowledge funding from the Economic and Social Research Council (ESRC) as part of a PhD studentship. Dr Hubel acknowledges funding from Lundbeckfonden (R276-2018-4581). Jessica Mundy acknowledges funding from the Lord Leverhulme Charitable Grant. Johan Zvrskovec and Abigail ter Kuile acknowledge funding from the National Institute for Health and Care Research (NIHR) Biomedical Research Centre and Guy's and St Thomas' NHS Foundation Trust.

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:

London Fulham Research Ethics Committee on 29th July, 2019 (REC reference: 19/LO/1254) gave ethical approval for EDGI UK. East of England - Cambridge Central Committee (REC reference: 17/EE/0025) gave ethical approval for the NIHR BioResource as a Research Tissue Bank.

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 and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.

Yes