Exploring the gut virome in fecal immunochemical test stool samples reveals novel associations with lifestyle in a large population-based study

Stool samples for fecal immunochemical tests (FIT) are collected in large numbers worldwide as part of colorectal cancer screening programs, but to our knowledge, the utility of these samples for virome studies is still unexplored. Employing FIT samples from 1034 CRCbiome participants, recruited from a Norwegian colorectal cancer screening study, we identified and annotated more than 18000 virus clusters (vOTUs), using shotgun metagenome sequencing. Only six percent of vOTUs were assigned to a known taxonomic family, with Microviridae being the most prevalent viral family. Genome integration state was family-associated, and the majority of identified viruses were unintegrated. Linking individual profiles to comprehensive lifestyle and demographic factors showed 17/25 of them to be associated with the gut virome. Physical activity, smoking, and dietary fiber consumption exhibited strong and consistent associations with both diversity and relative abundance of individual vOTUs, as well as with enrichment for auxiliary metabolic genes. We demonstrate the suitability of FIT samples for virome analysis, opening an opportunity for large-scale studies of this yet enigmatic part of the gut microbiome. The diverse viral populations and their connections to the individual lifestyle uncovered herein paves the way for further exploration of the role of the gut virome in health and disease. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This project would not have been possible without funding from the Norwegian Cancer Society, projects 190179 and 198048, the South Eastern Norway Regional Health Authority projects 2022067 and European Union Horizon 2020 Research and Innovation program under the Marie Sklodowska-Curie Action Grant agreement No 801133 - Scientia Fellow. The funding bodies played no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript. ### 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: Ethics committee Regional Committee for Medical Research Ethics in South East Norway (Approval no. 63148) gave ethical approval for this work. 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 FASTA files of vOTUs detected in 5 or more individuals, are available at ENA with accession number (data submission in process). Statistics on vOTUs are available as supplementary data. Due to the sensitive nature of the remaining data derived from human subjects, processing of data and/or biological material from this project must comply with the General Data Protection Regulation (GDPR). Data processing must have approval from the Regional Committee for Medical Research in Norway (REC). Furthermore, the processing needs legal basis according to GDPR Article 6 and 9 and the need for a Data Protection Impact Assessment (DPIA) according to GDPR article 35 must be considered. Requests for data access can be directed to Trine B Rounge, trinro@uio.no.