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A ready-made research platform: data, biosamples and imaging

[Jump to: Approved OHS Research Applications 2012-2024 | Our Research Principles | What’s new in OHS data | Researcher FAQs | Receive Research Updates | Featured Research]

225,000 participants. More than 15 years of self-reported health history, lifestyle and occupational data. Linkage to administrative health and environmental data. Blood samples, genomic data and imaging data. The Ontario Health Study offers a rich and expanding resource for researchers investigating cancer and chronic diseases, available now.

Questions? Contact our Research Operations and Access Officer at

Approved OHS Research Applications 2012-2024

  • Applications using OHS data: 77*
  • Applications investigating cancer: 26
  • Applications requesting biosamples: 6
  • Datasets requested: 75
  • ICES data linkages executed: 20
  • Ontario Health linkages executed: 9
  • Time to project approval (from a fully-complete application): ~60 days

*Includes 25 applications to use OHS data via CanPath

See all approved research projects here.

Our research principles

  1. Projects are evaluated on scientific merit, the impact on OHS participants, and appropriate use of Study resources


  2. OHS data are amplified when linked with datasets held by other data custodians, such as ICES and Ontario Health


  3. We provide de-identified data and biosamples to approved investigators for time-limited periods


  4. We value collaboration among researchers to encourage appropriate use of the Study’s finite resources


  5. In the spirit of shared scientific benefit, researchers are not given exclusive access to data or biosamples, or exclusive access to an analysis or question of interest

What’s new in OHS data

  • The OHS has over 3,000 magnetic resonance images of the brain, abdomen, heart and carotid artery provided by consented participants
  • The OHS has COVID-19 antibody data for almost 10,000 participants across 3 timepoints
  • Genotyping data for more than 20,000 participants

Researcher FAQs

The OHS was designed specifically for investigator-initiated retrospective or prospective research.

Unlike general disease or clinical cohorts, the OHS recruited participants regardless of illness or health, so researchers can follow the changes in participant health and exposures over time. Researchers use OHS data and biosamples to assess the effect of genetics, behaviour, family health history and environment on chronic diseases.

The OHS charges access fees on a cost recovery basis. Fees to access data and biosamples are set annually.

To request a cost estimate for your project, submit a Project Feasibility Assessment Form.

Researchers from industry or with private sector interests may apply for access to data and biosamples, and must meet the same rigorous application criteria and derived data requirements as academic applicants.

For more information on who can access the OHS platform and other requirements, please review the OHS Data and Biosample Access Policy.

OHS links personal, behavioural, environmental, health system and biological data so researchers can investigate cancer and chronic disease causes and determinants.

Of the 225,620 OHS participants (recruited 2009-2017), approximately 200,000 (89%) consented to linkage and 83% have been linked to the Ontario Health – Ontario Cancer Registry. The OHS is also linked to ICES data holdings, and to the Ontario Laboratory Information Systems (OLIS), which captures provincial biologic-based laboratory tests.

OHS participants have been linked to CANUE (the Canadian Urban Environmental Health Research Consortium). Linkages with CANUE and Statistics Canada’s Social Data Linkage Environment program allowed for the capture of historical residential exposures levels for ozone, air pollutants, nighttime light and green spaces, as well as climate and weather, making the OHS an ideal platform to study the effect of climate change on the health of participants.

One of our recruitment strategies included offering incentive-based gift cards or Air Miles. Participants recruited with this strategy have been less likely to contribute to follow-up studies or provision of biologic samples.

If this means that the OHS alone is not adequately powered for certain biospecimen-based research projects, the OHS is also part of the pan-Canadian population cohort, CanPath, that has over 150,000 baseline biospecimens available to approved researchers.

Yes, we help other studies recruit OHS participants to be part of their research projects. We have partnered with several investigators that sought to boost recruitment to their studies, or find matching control groups of participants with appropriate disease or demographic profiles.

Visit our Access and Linkage of OHS Data and Biosamples page to learn more about these ancillary studies. Contact to discuss your idea with our Research Operations and Access Officer.

Receive research updates

Be the first to know about new data sets, event invites, funding opportunities and more by signing up for the OHS Research Bulletin.

Latest Research Underway Using OHS Data

Diseases such as cancer, heart disease and diabetes are the primary causes of death in Canadian adults and treating these and other illnesses costs the Canadian health care system billions of dollars annually. The researchers using Ontario Health Study data are investigating factors that increase the risk of developing various diseases, as well as what can be done to reduce the chance of developing them. These risk factors may include where people live and work, what they eat, how much they exercise, whether they smoke and other factors that have not yet been identified.

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CanPath Webinar: Real-world insights on COVID-19 vaccine effectiveness and infection risk factors from CanPath’s SUPPORT-Canada study

Jun 28, 2023

Photo: Dr. Victoria Kirsh, OHS Scientific Associate. Photo Credit: Greg Sigurdson   At a hybrid event presented live and via webinar on May 30, 2023, OHS Scientific Associate Dr. Victoria Kirsh provided an update on CanPath’s national COVID-19 Antibody Study. Using real-world data from the SUrveying Prospective Population cOhorts for COVID-19 pRevalence and ouTcomes in Canada

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PHD student using OHS data to look for early signs of cancer

Mar 3, 2023

Nicholas Cheng is using data to compare over 400 OHS participants who’ve experienced a cancer diagnosis, with matched cancer-free participants, to look for biomarkers in the blood that could be used to detect breast, prostate and pancreatic cancers several years before a traditional diagnosis. Hear what motivates this PHD student, as he reflects on his

Latest Research Findings Resulting from OHS Data

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Boosting Immunity Insights: Collaborative Canadian Effort Contributes to Nationwide COVID-19 Immunity Study

Aug 17, 2023

TORONTO, Monday, August 14, 2023 – Today, CanPath (the Canadian Partnership for Tomorrow’s Health) has contributed to the first peer-reviewed publication showcasing pan-Canadian seroprevalence estimates – published in the Canadian Medical Association Journal (CMAJ). Seroprevalence refers to how many people across Canada developed antibodies in response to infection or vaccination. Studies like this give us an idea

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Provincial Variation in Colorectal Cancer Screening Adherence in Canada; evidence from the Canadian Partnership for Tomorrow’s Health (CanPath)

Jul 24, 2023

Data from more than 158,000 Canadians, including almost 80,000 OHS participants, were used to examine why so few Canadians follow recommended screening guidelines for colorectal cancer, even though regular screening is shown to reduce incidents of the disease or death. Based on self-reported data from online questionnaires, it turns out only 47.7 percent of the