For Participants

The Ontario Health Study (OHS) wishes to thank the more than 225,000 Ontarians who have registered and begun participating in the Study, as well as the over 41,000 participants who went the extra mile to provide a blood sample.

Current Activities

The OHS is conducting its first follow-up questionnaire. The deadline for completing the follow-up questionnaire is March 31, 2018.

A number of questions are similar to those on the baseline questionnaire. In addition to collecting updated information about your health, lifestyle, medical and family history, there are new questions related to:

  • eCigarette use
  • Marijuana use
  • Over-the-counter medication use
  • Mental Health

If you are a current participant, log in to your account to complete the questionnaire.

OHS Dataset and Biobank

OHS Dataset OHS Dataset

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.