OHS Research

Research using Ontario Health Study (OHS) data has begun!

Health researchers working in various disciplines across the province and around the globe are seeking to use the wealth of data collected in the OHS online questionnaire in their own research studies. Requests from researchers at accredited institutions must be approved by a Research Ethics Board and our Data Access Committee before access to de-identified OHS data is granted. Please see below for summaries of research that is currently underway using OHS data:

Principal Applicant: Sherry Grace, PhD, York University


Mental disorders are an important cause of disability and early death in Ontario. It is estimated that one in five Canadians will experience a mental illness in their lifetime. In this project, the psychosocial well-being of participants in relation to their determinants of health will be described within the context of the largest population-based study carried out to date in the province, the Ontario Health Study (OHS). A pilot study that included assessments of mental health and determinants of health was carried out prior to the main cohort OHS. The pilot questionnaire contains questions that measure psychosocial well-being by examining symptoms of depression and anxiety, social support, stress at home and work, and stressful life events. Psychosocial well-being will be described by social characteristics (such as age, gender, education, marital status, first language, ethnicity and household income) that may play a role in determining the health of an individual. Findings will be compared to what is previously known. The research may help identify determinants of health that contribute to mental disorders within Ontario and as a result, lead to measures aimed at reducing the effects of mental disorders.

Principal Applicant: Nancy Kreiger, PhD, Cancer Care Ontario

The purpose of this paper is to characterize the Ontario Health Study pilot cohort of 8,205 participants at baseline describing socio-demographic, self-reported health, nutrition, physical and lifestyle characteristics.

Principal Applicant: Tomas Paus, Baycrest


One of the most promising strategies for achieving personalized health is the identification of molecular signatures (biomarkers) with strong prognostic properties vis-à-vis an individual’s health. In our research program, we propose a trans-generational approach where we will investigate multiple generations of families to identify molecular signatures of health risk. Specifically, we will be investigating younger family members of an older family member (60+ years), living with or without a cluster of chronic diseases of the brain and body. With younger family members, we will be assessing the brain and body using magnetic resonance imaging (MRI) and high-throughput molecular profiling. We will assess a total of 5,000 individuals in the context of the Ontario Health Study (based in Toronto) as well as the Saguenay Youth/Parent Study and the Saguenay-based CARTaGENE subsample (both based in Chicoutimi. Quebec). Ultimately, the validated molecular signatures of individuals’ risk vis-à-vis common chronic disorders of the brain (depression, addiction, dementia) and body (hypertension, type-2 diabetes, dyslipidemia) may provide tools for disease prognosis, as well as early detection and intervention. It is likely that the same (or similar) signatures would be also useful as diagnostic tests and targets for drug discovery. Overall, disorders targeted by this proposal cost Canada ~$60 billion per year due to their early onset (adolescence) and chronic nature, both leading to a loss of years lived without disability. Development of prognostic signatures represents the first step towards reducing the economic and human burden associated with these disorders.

If you are a researcher and wish to access OHS data for use in your research projects please visit www.research.ontariohealthstudy.ca for more information on how to apply. Please note that this site is available in English only.

Over 225,000 adult Ontarians (2.36% of the eligible population) have completed our online baseline questionnaire, providing information such as personal and family health history, socio-demographics, personal exposures to tobacco, alcohol, and medications and detailed ethnicity and country-of-origin. 

Please Note:

  • Approval from a recognized Research Ethics Board or similar committee is required prior to the release of any de-identified individual-level OHS data. 
  • All data access policies and applications are available in English only and must be submitted in English as well.