Ontario Health Study
Ontario Health Study Summary

With more than 224,900 participants, the Ontario Health Study (OHS) is a rich resource for researchers investigating cancer and other chronic diseases. Researchers can now apply for access to de-identified data and biospecimens collected by the Study. Through the collection of health data and information through online questionnaires, physical measures and biosamples, the OHS is a rich resource for researchers to investigate how genetics, lifestyle and environment impact health.

Participants completed a nationally harmonized baseline questionnaire collecting social and economic demographics, personal and family health histories, medications, sleep patterns, alcohol and tobacco use, physical activity and environmental exposures. Regular follow-up questionnaires have been conducted to track changes in health, along with ad hoc questionnaires focusing on occupational history and impacts of the COVID-19 pandemic. Almost all participants (83%) have been linked with their administrative data such as the Ontario Cancer Registry. Data linkage opportunities with ICES, Ontario Health (Cancer Care Ontario) and CANUE are available.

Data from the following questionnaires are now available:

  • OHS Baseline Questionnaire
  • OHS Follow-up Questionnaire
  • OHS Work History Questionnaire
  • OHS and CanPath COVID-19 Questionnaire
  • OHS and CanPath COVID-19 Antibody Study Questionnaire

Non-fasting blood samples were collected from more than 40,000 participants. A subset of this group, approximately 12,600 and 12,800 participants respectively, provided urine samples and physical measures. Blood spot samples were collected from nearly 10,000 participants at up to three timepoints for the OHS and CanPath COVID-19 Antibody Study.

OHS Dataset and BioBank

  • >224,900 participants, of which >181,600 are participants of CanPath
  • >188,000 participants linked with administrative databases
  • >42,000 COVID-19 questionnaires
  • >40,000 blood samples
  • >12,800 physical assessments
  • 12,600 urine samples
  • >9,400 participants genotyped
  • >23,600 participants diagnosed with cancer

Learn more about the data and samples available to researchers here.


CanPath LogoThe OHS is one of seven participating cohorts of the Canadian Partnership for Tomorrow’s Health (CanPath), alongside the B.C. Generations Project, Alberta’s Tomorrow Project, Healthy Future Sask, the Manitoba Tomorrow Project, CARTaGENE in Quebec and the Atlantic PATH. CanPath is studying the biology, behaviours and environments of Canadians to learn more about the causes of chronic disease and cancer for a healthier Canada and world. To date, CanPath has collected data from over 330,000 Canadians. CanPath’s data and biosamples are available to researchers through the CanPath Portal.

Researchers are invited to apply to access Ontario Health Study data and biosamples to find ways to better treat and prevent cancer and chronic disease

Opportunities to Collaborate

Please visit OICR’s Collaborative Research Resources directory for more opportunities to collaborate.