For Researchers
What’s Available?
Questionnaire Data
- Baseline questionnaire completed by about 225,000 participants.
- Almost 1,400 variables describing social and economic demographics, personal and family health histories, medications, sleep patterns, alcohol and tobacco use, physical activity and environmental exposures.
- Follow-up questionnaire completed in March 2018. It asked participants for an update on their health and additional questions around e-cigarettes and marijuana use, mental health and over-the-counter drugs. Data from the Follow-up Questionnaire are now available.
- The Work History Questionnaire was completed in December, 2019.
- Regular follow-up questionnaires will be conducted to track changes in overall health.
Biosamples and Physical Measures
- Non-fasting blood samples were collected from more than 41,000 participants.
- The repository holds serum, plasma, red blood cells and buffy coat.
- For a subset of participants, (~6,000) there are lymphocytes in DMSO.
- ~6,400 samples have been genotyped through a Canadian Partnership for Tomorrow’s Health initiative using the UKBIObank Affymetrix arrays. Inflammatory markers have been assayed for a subset, including cytokine panels from 1,440 participants.
- Urine samples and physical measures were collected from 12,600 and 13,400 participants respectively. Physical measures include anthropometrics, blood pressure, resting heart rate, body fat percentage, grip strength and spirometry.
Physical measures and blood samples were collected through a variety of Study initiatives:
Regional assessment centres
Located in Mississauga, Owen Sound and Sudbury, men and women regardless of their health history were enrolled and invited to the nearest centre where they completed self- and interviewer-administered questionnaires, provided a number of physical measures and provided blood and urine samples. The assessment centres opened in 2009 and closed in July 2010. Approximately 7,600 participants were recruited.
Toronto assessment centre
Starting in 2013, a subset of participants visited an assessment centre in downtown Toronto and provided a series physical measures, completes a computerized cognitive battery, and provided blood and urine samples. Participants also had the opportunity to participate in a home sleep study. This centre was closed March 2014.
Local study centres
The OHS hosted a series of temporary blood collection clinics in communities across the province. More than 50 clinics were held from summer 2014 until March 2017.
LifeLabs blood collection program
Through a partnership with LifeLabs Medical Laboratories, participants were able to provide samples at LifeLabs locations across Ontario. This program ran until March 2017.
Additional Data Collection
- The Ontario Sleep Health Study collects accelerometry and sleep respiratory function from approximately 4,000 participants.
- The Canadian Urban Environmental Health Research Consortium (CANUE) is working to provide researchers with an index measuring exposures to air and noise pollution, green space and much more, for every postal code in Canada. By providing this location-based exposure data to studies like the OHS and many others, CANUE will allow environmental exposure data to be linked to our participants, providing additional information and making our platform even more useful to health researchers.
- The Canadian Alliance for Healthy Hearts and Minds has collected MRIs, and conducted Food Frequency Questionnaires and cognitive assessments from more than 3,000 participants.
Fast Facts about the OHS Cohort
Changes in participant cancer diagnoses at follow-up
Of the more than 20,000 participant-reported cancer diagnoses, the most common cancers identified at follow-up are below.
Changes in participant health at follow-up
The Follow-Up Questionnaire collected information on over 60 diseases and conditions from participants. Many of these are comparable to the baseline questionnaire. Below are some commonly-reported diseases.
Participant Demographics
Age Distribution (at recruitment)
Sex Distribution
Ethnicity