For Participants

The Ontario Health Study (OHS) wishes to thank the more than 225,000 Ontarians taking part in the Study, as well as the over 41,000 participants who went the extra mile to provide a blood sample. On March 31, 2018, the OHS concluded its first Follow-Up Questionnaire, which asked participants for updated information about their health, lifestyle, medical and family history, and asked new questions about e-cigarette use, marijuana use, over-the-counter medications and mental health. Additional questionnaires will become available soon.

Current Activities

The OHS team is developing the next questionnaire, which will be available to all participants in the spring of 2019. The Work History Questionnaire will ask about all the jobs you’ve had in your life, and will be used by researchers to examine the potential effects that different aspects of your work life have on your health.

The team is also making de-identified data and samples from the Study available to approved researchers in Ontario and internationally. Read how the information you’ve provided has already been used by health scientists, and learn about ongoing studies.

Data collected from OHS participants are now being used in several research projects underway as part of the Canadian Partnership for Tomorrow Project.

One project examines how closely provincial populations follow the recommended screening guidelines for breast, cervical, colorectal and prostate cancer.

Another explores how air pollution and the surroundings where people live (built environment) may affect metabolic syndrome (a cluster of conditions — increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels — that together increase the risk of heart disease, stroke and diabetes).

OHS Dataset and Biobank

OHS Dataset OHS Dataset

*These 900+ data points are common to other population health studies in Canada and around the world, allowing researchers to accurately compare results between studies and explore more challenging research questions.

By continuing to take part in the OHS, you'll be helping to find new ways to prevent and treat major diseases like cancer, heart disease and diabetes. You'll also help to improve the health of future generations.

Follow-up Questionnaires

By remaining involved in the OHS, you will be invited to complete periodic follow-up questionnaires which will track how your health changes over time. These questionnaires will also ask about your exposures to different chronic disease risk factors.


Stay Connected

Keep up-to date with Study announcements on our website here, or follow the OHS on Facebook and Twitter.