Home - Ontario Health Study Back to Top Ontario Health Study Participant Login Contact Us Français Facebook LinkedIn YouTube About the Study Frequently Asked Questions Our Team Study Leadership Our Researchers Supporters Your Privacy Contact Us Accessibility Statement For Participants Health Questionnaires HEAL Study Blood Collection Update Your Contact Information Username/Password Recovery For Researchers What’s Available? OHS Data and Biosamples Access and Linkage Managing Your OHS Research Project Research Approved to Access OHS Data Publications and Presentations OHS Research Bulletin News and Updates OHS Newsletter Study Updates Together, we’re leading the fight against cancer and chronic disease. We asked, you answered. The Ontario Health Study (OHS) research platform is now 17 years old. More than 225,000 volunteers across the province are making their personal health information available to researchers, opening the doors to potential new discoveries and strategies for preventing, detecting and treating cancer and chronic disease. I AM A PARTICIPANT See how health scientists are using the data you’ve provided and complete online questionnaires to keep on contributing to the growing OHS platform. I AM A RESEARCHER Access ready-to-use, high-quality epidemiological, clinical and biological datasets that can be easily linked to a wide range of administrative health data. Whats being studied? The OHS explores the ways lifestyle, the environment and genetics affect people’s health. With nearly 225,000 volunteers contributing health data over the course of their lifetimes, it’s one of Canada’s largest long-term health studies. It’s also part of something even bigger, feeding into CanPath, the Canadian Partnership for Tomorrows Health: the largest health research platform in Canadian history 0 Volunteer participants across Ontario 0 Non-fasting blood samples 0 Urine samples 0 Physical measurements 0 MRIs While we are not seeking new volunteers for the study, participants who have already signed up will continue to provide information on topics such as social and economic demographics, personal and family health histories, sleep patterns, medication and over-the-counter drug use, alcohol and tobacco use, cannabis and e-cigarette use, physical activity, mental health and environmental exposures. LEARN MORE ABOUT THE STUDY LEARN MORE ABOUT THE TYPES OF DATA BEING COLLECTED New email address? Moving? Let us know! Keep your contact information up to date Your de-identified data  is making a difference. Get the story here Curious about who helped choose the data to be collected in this study? Meet the OHS contributing scientists Online questionnaires give you the chance to tell us how your health has changed over time. Upcoming questionnaires Latest News The Ontario Health Study Newsletter, June 2026 Jun 11, 2026 Updates to the OHS Access Policy Jun 8, 2026 OHS participants contributed to research on Endocrine Disrupting Chemicals (EDCs) Video presentation Feb 27, 2026 OHS joins Ontario Biobanks Nov 11, 2025 Home About the Study Frequently Asked Questions Our Team Study Leadership Our Researchers Supporters Your Privacy Contact Us For Participants Health Questionnaires Blood Collection Update Your Contact Information Username/Password Recovery For Researchers What’s Available? Data Access Process Data Access Forms and Templates Research Underway Using OHS Data Research Findings Resulting from OHS Data News and Updates OHS Newsletter Study Updates Stay Connected Facebook LinkedIn YouTube Got Questions? Still need more information? Contact us. We’d be happy to answer any questions. © 2026 Ontario Health Study. All rights reserved. Privacy Policy | Terms and Conditions | Site Map