Back to Top

Research Approved to Access OHS Data

The following projects have been approved to use de-identified data from OHS participants, and have met all requirements of the Study’s data access process.

(Click each project below to read more)

Icon of a paper with checkmark on top

Approved Projects – 2020

Applicant: Drs. Philip Awadalla and Victoria Kirsh

Institution: Ontario Institute for Cancer Research

Approval Date: August 2020

Project Summary: We will leverage a decade of collaborative efforts by Canadian researchers, participants and international partners to rapidly generate high-quality data to support Canada’s response to the pandemic.

We will capture data and biologics to enable population-level surveillance, and enable researchers and clinicians to find factors contributing to COVID-19 susceptibility and severity (note: approval for additional biospecimen collection is not requested here and will be submitted in a separate request).

We developed the CanPath (Canadian Partnership for Tomorrow Project, which includes the OHS) COVID-19 online questionnaire in collaboration with over 90 national and international partners. With this online tool, we will collect information from population cohorts, patients from clinical cohorts and health care workers (through collaborations with UHN) and generate risk scores for infection and severity (using data on comorbidities, medication use, etc., adjusting for known confounders).

In addition to capturing a wealth of questionnaire data, we will focus on capturing administrative health and biosamples to prevent, detect, treat and manage COVID-19. We will leverage in-house research expertise to develop biomarkers to inform risk of disease, adverse outcomes and comorbidities. SUPPORT-Canada will include three core aims:

(1) Capture population and clinical-level COVID-19 data and outcomes to support personalized risk profiling, and inform adaptive public health responses;

(2) Create capacity for research in immunophenotyping, seroprevalence and host-viral genetics; and

(3) Explore genomic and co-morbidity/environmental interactions in shaping the pathophysiology of COVID-19 severity and susceptibility and immunological response.

Our platform has been designed to integrate with global research efforts to support clinical, immunological and genetic studies of COVID19. Our approach will enable rapid data sharing and translation of findings to the public health and research community.

Applicant: Dr. Victoria Kirsh

Institution: Ontario Institute for Cancer Research

Approval Date: June 2020

Project Summary: The Ontario Health Study is a population-based health cohort study that serves as a platform for investigating a variety of environmental, lifestyle, molecular, clinical and genetic factors associated with risks of cancer, vascular diseases, diabetes, and other chronic diseases.

To promote use of its extensive database among the health research community in universities, research institutes and government, we will publish baseline and follow-up descriptive data in the International Journal of Epidemiology (IJE).

We will address why the cohort was set up, who is in the cohort, how often they have been followed up, what has been measured, what has been found, what are the main strengths and weaknesses and details regarding how to get hold of the data.

We will report summary data – among OHS participants – on sociodemographic characteristics, physical measurements, prevalence of chronic conditions, incidence and mortality rates of various chronic diseases, and environmental exposures.

Applicant: Dr. Sasha Bernatsky

Institution: Research Institute of the McGill University Health Centre

Approval Date: April 2020

Project Summary: There is a growing interest in the role of air pollution on inflammation and disease. Fine particles (PM2.5) in air pollution can enter the body through airways and can trigger an inflammatory response. Gases from traffic-related and industrial air pollutants may also have a direct effect on inflammation and disease.

Our team has shown an association between road-traffic density and rheumatic disease onset in Montreal, found links between PM2.5 levels and rheumatic disease activity, and suggested PM2.5 and industrial emissions as triggers of rheumatic disease.

The key areas that remain unknown are what types of pollution exposures might be most important, for both risk of antibody development and rheumatic disease risk. Our proposal will fill these remaining important knowledge gaps.

Applicant: Dr. Victoria Kirsh

Institution: Ontario Institute for Cancer Research

Approval Date: April 2020

Project Summary: Lung cancer is the most common cancer among Canadians, accounting for 14% of all new cases and 26% of all deaths.

The lung cancer five-year survival rate is among the lowest of the leading cancer sites; it is 18% overall and only 4% when the disease has already spread to distant sites.

Lung cancer is very rarely diagnosed at an early stage because the disease presents with few symptoms; non-smokers, in particular, are much more likely be diagnosed at a later stage since physicians are not usually looking for it in non-smokers.

This is a large study population and includes a large number of both smokers and non-smokers; it will provide a unique opportunity to focus on lung cancer risk among non-smokers in particular.

We will study the link between several suspected risk factors for lung cancer and cancer risk among participants in the various cohorts that comprise the Canadian Partnership for Tomorrow’s Health.

We will assess the risk of cancer according to 1) residential radon, 2) outdoor air pollution, and 3) diet.

The risk of lung cancer among never smokers may be increasing, which provides a strong imperative for continued research.

Our study has many novel features and provides a unique opportunity to gain information on lung cancer risk in a Canadian population and to directly inform public health strategy and prevention of this highly fatal disease.

Applicant: Dr. Andrew Lim

Institution: Sunnybrook Research Institute

Approval Date: March 2020

Project Summary: Sleep and circadian rhythm disruption affect millions of Canadians and may be contributing to the growing number of adults with impaired cognition and Alzheimer’s disease (AD) and other dementias.

This study is combining data from wearable technologies for comprehensive sleep and circadian assessment in community-dwelling working aged adults with detailed cognitive testing and brain scans to fill important gaps in our knowledge about the impact of sleep and circadian disruption on the brain changes related to AD and other dementias.

This study will facilitate efforts to use sleep and circadian screening to identify adults at high risk for AD dementia, support clinical trials of existing and emerging sleep and circadian interventions to decrease the growing burden of impaired cognition in old age, and may lead to targeted therapies that improve brain health for the millions of Canadians who experience sleep or circadian rhythm disruption.

Applicant: Dr. Jeff Kwong

Institution: ICES

Approval Date: February 2020

Project Summary: There is unequivocal evidence that long-term exposure to outdoor air pollution, even at the relatively low levels observed in Canada, is responsible for increased incidence of, and mortality from, major chronic diseases (e.g., cardio-respiratory diseases).

However, little is known about the impact of air pollution on shaping individuals’ physiological transformations (various disease states, frailty, and death). This information is crucial for supporting health guidance and preventive interventions, as well as for estimating the health burden of air pollution.

In this study, we aim to investigate causal relationships between air pollution and the incidence of major chronic diseases (e.g., diabetes, myocardial infarction, stroke, HF, COPD and asthma), subsequent hospital readmissions for these conditions, and non-accidental death.

We will carry out state-of-the-art mediation analysis to identify key pathways underlying the impacts of air pollution on human health that are of public health significance.

Approved Projects – 2019

Applicant: Dr. Will King / Dylan O’Sullivan

Institution: Queen’s University

Approval Date: December 2019

Project Summary: Although a causal relationship between sun exposure and skin cancer has been established, a moderate level of Ultraviolet B radiation through sun exposure may be protective against some internal cancers such as breast, colorectal, and non-Hodgkin’s lymphoma. However, chronic ultraviolet radiation exposure may increase cancer risk through the suppression of the immune system and inflammation.

This research project will utilize data from the Canadian Partnership for Tomorrow Project (CPTP) to investigate the relationship between patterns of sun exposure and the risk for different cancer sites. Sun exposure will be estimated using a combination of personal sun behaviour and ambient ultraviolet radiation.

It is hypothesized that a protective effect will be observed for a number of internal cancer sites including breast, lung, colorectal, prostate, pancreatic, and bladder. The relationship with blood cancers is hypothesized to follow a U-shape.

The aim of this research is to identify and clarify the relationship between a modifiable risk factor and cancer risk. This research will examine the relationship between patterns of sun exposure and several high fatality internal cancers.

The unique UVR exposure profile of the Canadian population merits a study of these relationships within a Canadian population. In addition, this will be the first cohort study to assess the combined effect of ambient and personal sun exposure on site specific non-skin cancer risk.

The results of this research could provide clarity on the beneficial and detrimental types of sun exposure for site specific cancer development.

Applicant: Dr. Rachel Murphy

Institution: University of British Columbia

Approval Date: November 2019

Project Summary: In Canada, 1 in 2 people will be diagnosed with cancer during their lifetime, with lung and prostate cancer being two of the most common cancers diagnosed. Many of these cancers may be prevented through lifestyle changes, including changes to diet and physical activity levels. However, the link between lifestyle and cancer is poorly understood. Only age, race and family history are well-known risk factors for prostate cancer and little is known about modifiable risk factors for lung cancer beyond smoking.

The project aims to carry out a series of studies to identify the lifestyle, and environmental factors that may increase the risk that a person will be diagnosed with lung or prostate cancer. Using data from the Canadian Partnership for Tomorrow Project, we aim to investigate known and potentially new risk factors for prostate and lung cancer collected from physical measurements, questionnaires, and blood samples, including medical history, lifestyle (diet, body size, sleep, physical activity), and environmental factors (e.g. exposure to toxins).

Cancer development was determined over 9 years, during which time more than 800 lung and prostate cancers were diagnosed. People who were diagnosed with cancer will be matched with a person of the same age, sex, and follow-up time for comparison. Statistical modeling will be used to identify new risk factors that may help identify people who are at risk of developing cancer. This information will inform public health efforts to prevent these cancers in the future and improve the health of Canadians.

Applicant: Dr. David Soave

Institution: Wilfrid Laurier University

Approval Date: October 2019

Project Summary: Previous research have suggested that psychosocial factors (e.g., depression, experiencing the loss of someone close, anxiety) can increase the risk for developing cancer. However, the findings are very mixed – and studies tend to vary a lot in how they have looked at this (e.g., focusing specifically on breast cancer).

In order to look at this in a rigourous way – PSY-CA (PSYchosocial factors and CAncer incidence) is a study in the Netherlands that will use data collected in 18 international studies. Using information from cancer registries, it is possible to look at the relationship between these psychosocial factors and cancer incidence.

As this involves many participants, it is possible to not only look at specific types of cancer, but also to look at whether the increased risk for cancer is particularly present in specific subgroups (e.g., smokers, those who are overweight).

Furthermore, we will also look at whether health behaviours explain the relationship between psychosocial factors and cancer incidence: for example, depression may lead to a decrease in physical activity.

Applicant: Maria Cusimano

Institution: University of Toronto

Approval Date: October 2019

Project Summary: Hysterectomy, or removal of the uterus, is the most common major surgery performed on non-pregnant women in North America. At the time of hysterectomy, women are also offered the option of bilateral oophorectomy, or removal of both ovaries, in order to prevent the possibility of developing ovarian cancer, a deadly disease, later in life. However, removing both ovaries also triggers early menopause, which may lead to serious health problems like heart disease, stroke, dementia, and osteoporosis. Existing data on the consequences of removing the ovaries are unclear and have some limitations.

In order to better quantify the long-term health effects of removing the ovaries, we will perform a large study of adult Ontario women undergoing hysterectomy and bilateral oophorectomy. We will use a repository of data held at ICES, a non-profit research institute in Ontario. Our study will be the largest of its kind and will address many of the limitations of earlier studies. It will provide information that women and doctors need to make the right treatment decisions.

Applicant: Dr. Lyle Palmer

Institution: University of Adelaide

Approval Date: September 2019

Project Summary: This project will be conducted by some of the many scientists and clinicians who designed and implemented the recruitment phase of the Ontario Health Study (OHS).

Analyses will use the OHS online questionnaire data collected at recruitment. We will conduct the analyses necessary to describe the OHS cohort’s design, methods, and the sample recruited at baseline. Detailed comparisons will be made to census data from Ontario.

Applicant: Dr. Prabhat Jha

Institution: Centre for Global Health Research, St. Michael’s Hospital

Approval Date: August 2019

Project Summary: Smoking remains a major cause of premature death worldwide. Despite a significant reduction in the frequency of adult smoking in high-income countries, about one-quarter of all deaths between 30 and 69 are still caused by smoking.

Recent studies have shown the smokers who start early in life and don’t quit can expect to save a full decade of life. In our previous study conducted using US NHIS data, we found that smokers lose at least one decade of life expectancy, as compared with those who have never smoked, and cessation before the age of 40 years reduces the risk of death associated with continued smoking by about 90%.

Similar benefits of cessation on overall mortality were found in other studies.However, the absolute and relative risk reduction in clinically relevant subpopulations (e.g. among those who are diabetic, obese or hypertensive) remain unknown.

Similarly, the benefits of cessation for different diseases, notably ischemic heart disease, stroke, various cancers and respiratory disease in subpopulations also remain unknown. Finally, the absolute and relative benefits of cessation might well differ by social status (or socioeconomic status). Such examination of benefits of cessation requires very large sample sizes, with careful attention to reverse causality (as disease can itself induce cessation).

This project will quantify the disaggregated benefits of smoking cessation within the OHS cohort, and be accompanied by similar analyses in other cohorts around the world. This study will help provide information to smokers on the benefits of cessation.

Applicant: Dr. Geoffrey Anderson

Institution: University of Toronto

Approval Date: June 2019

Project Summary: We have been able to make progress in our efforts to prevent death from breast cancer by making sure we catch breast cancer as early as we can. 

The earlier we find breast cancer the better the chance that we will be
able to treat it effectively.

This project will help us understand how we can make sure women get the breast screening they need and that we find the breast cancer as early as possible.

Applicant: Dr. Geoffrey Anderson

Institution: University of Toronto

Approval Date: June 2019

Project Summary: Breast cancer is the most common form of cancer in women. Advances in treatment mean that more women are living longer after their breast cancer diagnosis. Research has shown that heart disease is a common cause of death in older women with breast cancer.

This research will determine which factors predict heart disease in women with breast cancer. This will allow women with breast cancer and their doctors to find out if they are at high risk for heart disease. This will help guide decisions related to breast cancer treatment selection and follow-up, improving patient outcome and quality of life.

Approved Projects – 2018

Applicant: Dr. Darren Brenner

Institution: University of Calgary

Approval Date: October 2018

Project Summary: A University of Calgary epidemiologist is using data from Ontario Health Study (OHS) participants to explore how environmental or lifestyle factors could be associated with breast cancer in younger women.

Dr. Darren Brenner recently gained approval to study the de-identified data for female participants who were ages 35 to 50 and cancer-free at the time they joined the OHS. Questionnaire data from the OHS will be combined with Ontario Cancer Registry data to focus his work on those who have subsequently had a cancer diagnosis since joining the OHS.

Comparatively little is known about the risk factors for young-onset breast cancer, Brenner noted in his application to use OHS data. Inherited genetic mutations play a role, but generally only account for 5% to 10% of young-onset cases, suggesting lifestyle or environmental factors may contribute to the development of breast cancer in younger women. The role of obesity needs further study, he noted, as recent studies suggested a decreased risk for breast cancer in younger women with obesity.

Younger women diagnosed with breast cancer tend to have poorer survival rates because they are not routinely screened, and so tend to have an already-advanced stage of cancer once they are diagnosed.

Breast cancer remains the most commonly diagnosed cancer among Canadian women. Though the number of cancer diagnoses in older women has gone down over the last 25 years, the number of women under age 50 who receive a breast cancer diagnosis has increased. According to the Canadian Cancer Society, breast cancer accounts for 23% of diagnosed cancers in Canadians aged 30 to 49[1]. On a positive note, female breast cancer death rates have decreased an estimated 48% since they peaked in 1986[2].

In addition to using questionnaire data and blood samples from OHS participants, Dr. Brenner is also pulling similar data about British Columbian and Albertan women, through the Canadian Partnership for Tomorrow Project, Canada’s largest population cohort study.

Dr. Brenner and his team will examine the impact of lifestyle, environmental, and reproductive factors, family and medical history, as well as breast cancer screening protocols, on the risk for breast cancer in women under 50.

Results from their investigation could improve researchers’ understanding of young-onset breast cancer causes and could lead to improved prevention strategies.

Read more about Dr. Brenner and his other research projects in this article: ‘Research Rockstar’


[1] Canadian Cancer Statistics 2019 p. 14

[2] Canadian Cancer Statistics 2019 p. 7

Applicant: Dr. Vikki Ho

Institution: Centre de recherche du CHUM

Approval Date: September 2018

Project Summary: Worldwide, colorectal cancer is the third most common cancer. Men are more likely to develop colorectal cancer than women. Different environmental, lifestyle and biologic factors may explain this difference. Also, research is uncovering the role of estrogen, a hormone that promotes the development and maintenance of female characteristics, in preventing colorectal cancer in women.

Less is known of the role of hormones in the development of colorectal cancer in men. Similar to the evidence in women, there is support that the proper functioning of sex hormones may prevent colorectal cancer in men. Endocrine disruptors are chemicals that interferes with the proper functioning of sex hormones. We are exposed to these chemicals in the environment and in diet; however, workers in certain sectors are highly exposed to endocrine disruptors.

In this research, we will examine whether exposure to endocrine disruptors in the workplace increases the risk of colorectal cancer. Our research will be based within participants of the Canadian Parternship for Tomorrow Project. This study included men and women who have shared information on their health, lifestyle, environment and behaviours. Our research will include all men and women who were newly diagnosed with colorectal cancer since 2009. For comparison, we will select a sub-group of people, who have not had cancer at the beginning of the study. The interview asked detailed questions on the longest-held job for all participants. Using this information, we will determine whether exposure to endocrine disruptors at the longest held job was probable or not. We will compare the number of colorectal cancer cases among participants who were probably exposed to endocrine disruptors to those who were never exposed. This study offers a valuable opportunity to examine, in a short time frame and at low cost, whether endocrine disruptors play an important role in colorectal cancer risk.

Applicant: Dr. Vikki Ho

Institution: Centre de recherche du CHUM

Approval Date: September 2018

Project Summary: Being physically active have been shown to reduce the risk of some cancers. There are different types of physical activity, including activity at work and recreational activities. Participation in recreational activities has been shown to reduce lung cancer risk. However, the role of physical activity at work in affecting the development of lung cancer is not well-established. In fact, some studies have found that people who have physically demanding jobs also have a higher risk of lung cancer. As people spend many hours at work and some jobs are very physically demanding, new studies are needed to fully understand the role of physical activity at work on lung cancer development.

In this research, we will examine how lung cancer risk is associated with physical activity levels at work. Our research will be based on an ongoing Canadian study that began in 2009. Our research will include all men and women who were newly diagnosed with lung cancer since the study began. For comparison, we will also select a subgroup of people, who did not have a cancer at the beginning of the study. The interview asked detailed questions on the longest-held job for all participants.

Using this information, we will compare activity levels in the longest-held job between those who were diagnosed with lung cancer and those who remained cancer-free. This study offers a valuable opportunity to examine, in a short time frame and at low cost, whether physical activity at work plays an important role in lung cancer development.

Applicant: Dr. Sasha Bernatsky

Institution: Research Institute of the McGill University Health Centre

Approval Date: June 2018

Project Summary: The over-arching goal of our CAN-AIM team is to enhance the validity and accuracy of research on real-life comparative effectiveness and safety of drugs. Comparative effectiveness research is the direct comparison of existing therapies, in order to understand which treatment works best for which patients.

The same approach can be applied to assess ‘comparative safety’; that is which treatments pose the least potential harms. The aim is to allow decision-makers to know which treatment has the most favorable benefit-risk profile, for whom and under what circumstances.

Applicant: Dr. Dennis Ko (formerly Dr. Jack Tu)

Institution: ICES

Approval Date: April 2018

Project Summary: In this study, we plan to link survey information collected in the Ontario Health Study to other sources of health data, for example, hospitalization data and physician visit data.

The purpose of the study is to determine the cardiovascular (CV) risk factors, health services use, and clinical experience of survey participants at the level of individuals and communities.

This study will help us determine how representative participants of the survey are of the Ontario population; information that will be important for future research that uses the survey data.

Additionally, the community profiles we plan to develop as part of this study will improve our understanding of personal health behaviours and the influence of access to and the quality of health services on clinical events experienced by individuals within the community.

Finally, we will determine how well an established risk model for predicting cardiovascular disease performs in this cohort and whether we can develop better prediction models using the linked survey data.

Approved Projects – 2017

Applicant: Dr. Philip Awadalla

Institution: Ontario Institute for Cancer Research

Approval Date: August 2017

Project Summary: We will link participants in the Ontario Health Study with Cancer Care Ontario records in an attempt to better comprehend the development of specific cancers, such as breast cancer, prostate cancer, pancreatic cancer and all blood based cancers (myelomas, leukemia, and lymphomas). Specifically, we aim to develop early detection methods/biomarkers present in biosamples (blood, plasma, urine and genomic) before the first cancer diagnosis.

The OHS is a unique cohort relative to clinical cohorts, in that we have data and biologics collected from individuals who entered the study without a disease diagnosis and who have subsequently developed disease during the time that they participated in the study. The self-reported data, collected through baselines and follow-up questionnaires, can be used to test for associations between biological changes and changes occurring in response to disease status, environmental exposures, or drug regimens.

Administrative health linkages, obtained through Cancer Care Ontario, will provide us access to administrative health data that can be used to validate the self-reported data.

Approved Projects – 2013

Applicant: Dr. Sutapa Mukherjee and Woganee Filate

Institution: Women’s College Research Institute

Approval Date: April 2013

Project Summary: Sleep apnea is prevalent and is associated with significant morbidity. Additionally, previous research has shown racial and ethnic variations in sleep duration and sleep quality in a large sample of US survey respondents. Unfortunately the sleep patterns of Ontarians have never been described. Moreover, little is known of the ethnic differences in sleep patterns in a Canadian population. The Ontario Health Study will provide self-reported sleep characteristics from a large representative sample of ethnically diverse adults in Ontario.

Applicant: Dr. Marc Berman

Institution: Rotman Research Institute at Baycrest

Approval Date: January 2013

Project Summary: Many of us fail to realize just how much the surrounding environment impacts our behavior. Researchers have found that graffiti on mailboxes increase the propensity of people to steal (Keizer, Lindenberg, and Steg, 2008), and that dilapidated neighborhoods encourage crime (Johnson, 2009).

But the environment can also have positive effects; there is a growing literature showing that brief interactions with nature, such as a walk in a park, can have beneficial effects on mental and physical health (Berman et al., 2008; Berman et al., 2012; Kaplan & Berman, 2010; Ulrich, 1984; Kuo & Sullivan, 2001; Cimprich & Ronis, 2003).

In this project, we will examine these relationships on a much larger scale: we will ask whether the naturalness of different neighborhoods around the Greater Toronto Area is related to physical and mental health, while controlling for confounding variables such as SES.

We will also be able to uncover the relationships between mental and physical as moderated by the naturalness of the environment. This project will help us to quantify the health benefits of naturalness in urban areas, which will have wide ranging applications for both health scientists and policy makers.

Approved Projects – 2012

Applicant: Dr. Sherry Grace

Institution: York University

Approval Date: March 2012

Project Summary: 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 contect 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 of 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.