{"doi":"10.1093/ije/dyac156","title":"Cohort Profile: The Ontario Health Study (OHS)","abstract":"The Ontario Health Study (OHS) is a resource for investigating the ways in which lifestyle, the environment and genetics affect people’s health. It is one of the regional cohorts that collectively form the Canadian Partnership for Tomorrow’s Health (CanPath)—a pan-Canadian cohort with >330 000 participants. The linking of Canada’s rich collection of administrative health data with the cohort’s data represents a powerful means to disseminate high-quality, timely data. From 2009 to 2017, the OHS recruited participants from the general population of Ontario through targeted recruitment strategies. Adult residents of Ontario aged ≥18 years were eligible for inclusion; the mean age at recruitment was 46 years (range: 18–97 years). A total of 225 620 people (137 918 female, 87 702 male) comprise the OHS baseline cohort. At study entry, cohort members completed a questionnaire that collected information on socio-demographics, family history, health status, behavioural factors, lifestyle factors and self-reported anthropometry. A subset of participants provided blood samples and physical measures. A follow-up questionnaire was administered from 2016 to 2019, a work-history questionnaire in 2019, and COVID-19 questionnaires and dried blood spots were collected from 2020 to 2022. Biologic samples have supported genotyping and whole-genome sequencing, and repeat blood spots have supported COVID-19 serology studies. Participants are followed actively through questionnaires and passively via linked environmental and administrative health data. Data and biosamples are available to researchers through a data and sample access process (e-mail: [email protected]). The prevalences of many chronic diseases—including cancer, cardiovascular disease, asthma and type 2 diabetes—have increased in Canada and many other countries over the past 30 years.1–4 In 2020, cancer and heart disease were the leading causes of death for Canadians, accounting for 48% of all deaths.5 About 37% of seniors (aged ≥65 years) have at least two common chronic diseases, with almost 50% of seniors aged ≥85 years suffering from multimorbidity.6 Chronic diseases are associated with high healthcare costs,7 rising complexity of care, long-term morbidity and mortality,8 and as such are major public health problems both in Canada and the rest of the world. A better understanding of their natural histories and complex and interrelated causes is needed to bring about the promise of disease prevention and early detection. Established to facilitate prospective observational health research, the Ontario Health Study (OHS; OntarioHealthStudy.ca) is a longitudinal population-based regional cohort study, designed to assess an extensive range of exposures and a wide range of health-related outcomes over a long period of time. It serves as an integrated platform for investigating the interplay of environment, lifestyle and ‘-omic’ (such as genomics, metabolomics, transcriptomics, proteomics) factors that increase individual and community risk of developing cancer and other common adult diseases. The intent is to engage participants in ongoing data collection over their lifespan, to follow them over time both actively and passively, and to make genomic, environmental, lifestyle and electronic health-related data available to the scientific research community. Derived variables, including data generated from biologic samples, are returned to the cohort to further enrich the data holdings. The OHS is a major contributing cohort within the national Canadian Partnership for Tomorrow’s Health (CanPath; CanPath.ca),9 a pan-Canadian cohort with >330 000 participants, that includes seven regional cohorts spanning all 10 provinces: BC Generations Project,10 Alberta's Tomorrow Project,11 Healthy Future Sask (Saskatchewan), Manitoba Tomorrow Project, CARTaGENE (Quebec)12 and the Atlantic Partnership for Tomorrow’s Health.13 Mandated recruitment goals were surpassed, and both the OHS and CanPath are t","journal":"International Journal of Epidemiology","year":2022,"id":245604,"datarank":0.6388694255023308,"base_score":3.044522437723423,"endowment":3.044522437723423,"self_citation_contribution":0.4566783656585135,"citation_network_contribution":0.1821910598438174,"self_endowment_contribution":0.4566783656585135,"citer_contribution":0.1821910598438174,"corpus_percentile":69.00286222634796,"corpus_rank":4008,"citation_count":20,"citer_count":13,"citers_with_citation_signal":7,"citers_with_endowment":7,"datacite_reuse_total":0,"is_dataset":true,"is_dataset_confidence":0.9364,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":880711,"name":"Kimberly Skead","orcid":"0000-0001-5652-1399","position":1,"is_corresponding":false},{"id":880712,"name":"Kelly McDonald","orcid":"0009-0005-7405-6810","position":2,"is_corresponding":false},{"id":20413,"name":"Nancy Kreiger","orcid":null,"position":3,"is_corresponding":false},{"id":1501,"name":"Julian Little","orcid":"0000-0001-5026-5531","position":4,"is_corresponding":false},{"id":881347,"name":"Karen Menard","orcid":null,"position":5,"is_corresponding":false},{"id":380510,"name":"John McLaughlin","orcid":"0000-0001-6453-7577","position":6,"is_corresponding":false},{"id":567127,"name":"Sutapa Mukherjee","orcid":"0000-0001-5021-1648","position":7,"is_corresponding":false},{"id":20414,"name":"Lyle J. Palmer","orcid":"0000-0002-1628-3055","position":8,"is_corresponding":false},{"id":880713,"name":"Vivek Goel","orcid":"0000-0002-1389-2007","position":9,"is_corresponding":false},{"id":241831,"name":"Mark P. Purdue","orcid":"0000-0003-1177-3108","position":10,"is_corresponding":false},{"id":267583,"name":"Philip Awadalla","orcid":"0000-0001-9946-6393","position":11,"is_corresponding":false},{"id":317205,"name":"Victoria A. Kirsh","orcid":"0000-0003-2422-2225","position":0,"is_corresponding":true}],"reference_count":37,"raw_metadata":null,"created_at":"2026-07-19T00:23:39.284121Z","pmid":"35962976","pmcid":"PMC10321700","fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}