Frequently Asked Questions


The measurements and samples that are collected at the Assessment Centre will help researchers to better understand the factors that influence our health and quality of life. They may help to improve the prevention and diagnosis of chronic diseases such as cancer, heart disease and diabetes. Also, participation in the Ontario Health Study may allow you to learn something that you did not know about your health.

  • After learning about the Assessment Centre on our website, please log in to your home page to complete the online consent form. You can log in to your home page by selecting the “Already Registered? Log In” link located at the top right-hand side of the OHS website;
  • Next, you will be asked to complete a brief online questionnaire that will make the measurements and samples we collect at the Assessment Centre more useful to researchers. The OHS Assessment Centre questionnaire will be available on your home page after you complete the consent form;
  • Once you have completed the consent form and the questionnaire, you will be able to make an appointment using our online booking tool. The link for booking your visit to the Assessment Centre is available on your home page.

If you haven’t received an invitation but are interested in visiting the Assessment Centre, you may be prompted to indicate your interest in making an appointment the next time you log into your home page. You will be contacted when appointment times open up, however it is not possible to determine exactly when you will be sent an invitation. Depending on the volume of interest, the wait time could range from a few days to several months.

The Assessment Centre questionnaire asks about specific areas of your health. This information will help researchers to better understand your test results from the Assessment Centre. The questionnaire takes approximately 10 minutes to complete and you are free to stop at any point and come back to it later. Some of the areas it asks about include:

  • Cardiovascular health
  • Neurology and memory
  • Respiratory health
  • Emotional health and well-being
  • Joints and body pain
  • Sleep
  • Personal medical history
  • Alcohol use
  • Tobacco use

You may notice that some of the questions from the baseline questionnaire are repeated in the Assessment Centre questionnaire. The reason for this is that for some participants, more than a year may have passed between completing the baseline questionnaire and visiting the Assessment Centre. The information we collect from you at the Assessment Centre is most useful when we have an up-to-date picture of your health.

For Assessment Centre inquiries please call 647-260-6458, or toll free to our call centre at 1-866-606-0686. Please note that the call centre is open Monday to Friday from 9 a.m. to 5 p.m. Email inquiries can be sent to info@ontariohealthstudy.ca.

The Assessment Centre is located in Toronto at 790 Bay Street, on the southwest corner of Bay and College Streets. Should you need to contact the Assessment Centre, please call 647-260-6458, or toll free to our call centre at 1-866-606-0686. The closest TTC stations are College and Queen’s Park. Parking is available at 790 Bay Street for $3.00 per half hour and at 777 Bay Street for $8.00 per hour. Please note that parking at 790 Bay Street is open Monday to Friday from 6:00 am – 7:00 pm, and is currently cash only.

Detailed directions will be emailed to you when you make an appointment at the Assessment Centre.

Please be prepared to spend about one hour at the Assessment Centre.

  • Please arrive at the Assessment Centre a few minutes before your appointment;
  • Please bring a piece of photo identification (e.g., driver’s license, OHIP health card, passport) to show when you check in at your appointment.
  • You may eat and drink before your appointment, unless you are providing a fasting blood sample (in which you don't eat or drink anything other than water after midnight the night before your visit).
  • Please wear comfortable clothing that is not too bulky;
  • Please avoid wearing pantyhose or tights (you have to be barefoot for some of the physical measures).

An Assessment Centre staff member will take physical measurements, such as your height, weight and percentage of body fat. Here is a description of each measurement that will be conducted at the Assessment Centre:

  • Standing & Sitting Heights: We will measure your standing and sitting heights to calculate the length of your legs and body.
  • Weight & Body Fat Percentage: In order to measure your muscle and fat tissue, you will be asked to remove your shoes and socks and to stand on a scale-like machine.
  • Waist, Hip & Neck Circumferences: The size of your waist, hips and neck will be measured with a tape measure. To do this correctly, we may ask you to shift or remove bulky clothing.
  • Blood Pressure & Resting Heart Rate: Your blood pressure and heart rate will be recorded by an automatic machine. You will be asked to sit quietly with your feet flat on the floor during these measurements.
  • Lung Function: After taking a deep breath, you will be asked to blow as hard as you can into a tube connected to a computer. You will be asked to wear a nose-clip to make sure air doesn’t escape through your nose. This test measures how well air moves into and out of your lungs.
  • Hand-Grip Strength: You will be asked to squeeze a small tool in your hand as hard as possible. This will measure upper body strength.

While at your appointment, you will be asked to provide blood (less than two and a half tablespoons) and urine (less than one tablespoon). If you choose to book an appointment that begins before 10:00 a.m., you will be given the option to provide a fasting blood sample (in which you don’t eat or drink anything other than water after midnight the night before your visit). If you usually take any medication in the morning, please ensure that you take it as usual with a glass of water. If you book an appointment that begins later in the day or you choose not to provide a fasting blood sample, you may eat and drink normally before your appointment. Once you have provided your blood sample, you will be given something to eat before moving to the next part of your visit.

There are no major risks associated with taking part in Assessment Centre tests.
Potential minor risks associated with the physical measurements may include:

  • Blood collection can occasionally cause bruising, pain or, in rare circumstances, loss of consciousness;
  • The breathing/lung function test can occasionally cause dizziness or, very rarely, loss of consciousness. It is not recommended that you do this test if you are suffering from a cold, flu or bronchitis. Please inform the Assessment Centre staff if you have any of these conditions;
  • You might learn something about your health that that you didn’t know about, such as elevated blood pressure or slightly lower lung function. This might make you feel anxious or worried. Assessment Centre staff will be available to answer any questions you have about the measurements recorded during your visit.

Other potential risks:

While we make every effort to protect the confidentiality of the physical measures taken at the Assessment Centre and the samples collected, there is a small risk that the security of the system could be compromised in some way. Because of the privacy and security measures in place (described in the FAQ "How will my privacy be protected?"), it is unlikely that any unauthorized person who gained access to the system could identify the measures and samples you have provided as belonging to you. You may contact the Ethics Review Office at the University of Toronto if you have any questions or concerns about your rights as a research participant: ethics.review@utoronto.ca or 416-946-3273.

When you completed the baseline questionnaire, you may have given the OHS permission to access personal health information about you that is kept by other organizations, such as the Ontario Cancer Registry. Linking to this information gives researchers a more complete picture of specific health issues. If you did give consent, the information you provide as part of your Assessment Centre visit – including the Assessment Centre pre-visit questionnaire, measurements collected at the Assessment Centre, and results of blood or urine tests – will be linked with the information that you provided on your baseline questionnaire and the information kept by other organizations.

Most of your blood and urine samples will be frozen so that researchers can look at them in the future. Your samples will be stored until they are no longer needed for research purposes. Some of the studies that may be done with your sample will involve looking at blood markers, called biomarkers, of disease. By providing a blood sample, it will also be possible for researchers to look at your DNA and other parts of your blood. If researchers extract your DNA, it will be kept in a small plastic tube with an identification code. No personal information will kept on the tubes. Your urine sample will be divided up and frozen for researchers in the future, and could be used to look at kidney function, nutritional and dietary information, environmental exposures, and other things. All of your samples will be stored in secure freezers.

Current technology, such as ‘next-generation’ sequencing, has improved our ability to study the genetic basis of diseases and conditions because it is now possible to find disease-causing genes with a relatively small number of participants. We anticipate that researchers who access your blood sample in the future might want to sequence your DNA. DNA is long lasting and may be stored for an indefinite period of time. Therefore, in the future it could be tested in currently unknown ways. Unless researchers uncover something that could be threatening to you or reveals a serious condition that can be treated or prevented, you will not receive the results of any of the future analyses of your blood.

A small amount of your blood sample will be analyzed at a lab at Mount Sinai hospital immediately after your Assessment Centre appointment. The blood tests that will be performed are:

  • Complete Blood Count: The cells in your blood will be analyzed to look for anemia, infection and other diseases. This test gives a general indication of your health.
  • Glycosylated Hemoglobin Analysis: This test measures the long-term level of sugar in your blood, and is used to detect and monitor cases of diabetes. This test will help researchers study diabetes, heart disease and obesity.

Your results will be posted to your personal home page about 10 business days after your Assessment Centre appointment. If any of your results are considered outside of the normal range, this will be noted in your report. Please keep in mind that even if your results aren’t considered ‘normal,’ it does not necessarily mean there is anything seriously wrong with you. If you are concerned about your results, we suggest you see your family physician or visit a walk-in clinic as only a physician will be able to interpret your test results in the context of your overall health and determine if these results are problematic. If a very serious condition is found during any of the blood tests, a staff member will contact you within two business days of your Assessment Centre appointment using the phone number you provided when booking your appointment.

The results of the immediate analyses of your blood will be stored until they are no longer needed for research purposes. These results will be “coded,” meaning that a sequence of numbers will be assigned to your results so you cannot be identified. A small sample of your blood will be kept to look at biomarkers in the future. You will not receive the results of these biomarker tests.

On the day of your visit to the Assessment Centre, you will be given the results of some of your physical measurements. A small amount of your blood sample will be analyzed immediately after your Assessment Centre visit and the results, along with the results of your physical measurements, will be posted on your home page within approximately 10 business days.

Powerful technologies now exist that let researchers look at the data and samples you have provided in ways that were not possible in the past. Because of this, researchers who use the data or samples you have provided in future analyses may discover something unexpected that is outside the aim of the study they are conducting. This is referred to as an “incidental research finding.” It is possible that a researcher will uncover something that could be life-threatening to you or reveal a serious condition that can be treated or prevented. More importantly, if you knew about the condition, you might be able take steps to avoid it. Working with a Research Ethics Board, the researchers doing the analysis and the Ontario Health Study will look at incidental research findings on a case-by-case basis to determine how they should be handled.

If there are no such incidental findings, you will not be informed of your individual results if your measures or samples are used by researchers in the future.

We know how important it is to keep information about your health private and confidential. When measures and samples are collected, anything that personally identifies you, such as your name, will be removed and replaced with a unique code. This unique code will let us link the measures and samples you have provided to you while allowing us to keep your identity confidential. Only a handful of staff at the Ontario Health Study have access to the electronic key that matches your unique code to your identity.

All coded information is “encrypted” (scrambled) before it is transferred from the Assessment Centre to the Ontario Health Study databases. Coded information is only transferred over secure connections similar to those used by banks. These secure connections are very difficult for outsiders to breach. The coded information is then stored on encrypted servers (very large computers) in a locked room that very few people have the authority to enter. We only unscramble the information after it has safely arrived on our servers. The measures you provide will be stored on a separate server from your questionnaire responses or anything that personally identifies you (e.g., name, address, OHIP number).

Everyone who works for the Ontario Health Study must sign a confidentiality agreement. So if a staff member happened to come across something that could identify a participant, this information would be held in the strictest confidence.

Since the results of your physical measures and immediate blood tests will be posted to your personal home page, it is very important for you to have a strong password to make sure only you are able to access your home page. Please choose a password that is 6-14 characters in length and includes at least one symbol (such as #, !, *).

Although it is not mandatory, please bring one piece of photo identification (e.g., driver’s license, OHIP health card, passport) for verification when checking in at your appointment. Should Ontario Health Study staff be unable to locate your appointment in the system, identification will be required.

The data and samples that are collected by the Ontario Health Study will be available to researchers at recognized institutions in Canada and abroad. Access to the data and samples is governed by strict guidelines that protect the confidentiality of participants. All researchers using data from the Study must receive approval from a research ethics board or similar committee before access is given. Researchers will only have access to “double-coded” data, meaning the data has been re-coded from when it was first collected to provide an additional level of protection. Researchers will not be able to access any information that would allow them to identify you or any other participant.

No information about you will be given to your employer, family members or commercial entities such as insurance companies.

If Assessment Centre staff are concerned by the results of any of your tests, you will be told of this concern and appropriate action will be taken. This action might include having a physician review the measurement or test or accompanying you to an urgent care unit/emergency department at a hospital. All results will also be posted on your home page and if there is anything of serious concern, an Assessment Centre staff member will get in touch with you.

While conducting a research study, it is possible that a researcher could uncover something that may be important for you to know regarding your health. An example of this could be a situation in which the research results show that you are at serious risk for developing a condition, but there are steps you could take to avoid or reduce the harm from it. Working with a research ethics board, the researchers doing the analysis and the Ontario Health Study will look at these cases on an individual basis to determine how they should be handled.

The results of research using data and samples from the Ontario Health Study may assist businesses, including pharmaceutical companies, to develop new therapies and improve existing treatments. Your individual test results or coded samples will never be given to industry groups, however. The Ontario Health Study and the researchers we work with will complete any analysis “in-house” and industry groups may be provided with a summarized report of these analyses. You will not receive personal financial benefit from the sale of any test or product that may be developed using the measures and samples collected by the Ontario Health Study.

You will not be paid for coming to the Assessment Centre, and we cannot reimburse you for any costs that you may pay when visiting the Assessment Centre. However, we are able to provide two TTC subway tokens to everyone who attends an appointment at the Assessment Centre. As a thank you for participating, you will receive a promotional code that can be redeemed for a $10 gift card at a variety of retailers. You will receive this gift even if you aren’t able to complete all of the measures at the Assessment Centre.

When you collect your incentive, the company that provides the incentive may know that you have visited the Assessment Centre, but none of the information that you have provided to the Ontario Health Study will be made available to the company. To be able to receive the incentive you will need to provide your name, mailing address, phone number and email address (optional) to the company. This information will only be used by the company for the purpose of fulfilling your selected incentive and for business analytics. This information will not be retained by the company or sold to third parties and will not be used by the company for further contact in the future once the incentive has been received.

Participation in the Ontario Health Study is voluntary and you can withdraw your consent for any or all of the measurements at any time without providing a reason. The withdrawal button can be found on your home page. If you choose to withdraw, you will have the following choices about what happens to the data that you have provided, including your physical measurements and samples:

1. No further contact: The Ontario Health Study will no longer contact you or ask you to participate in ongoing Study activities, but will continue to have your permission to keep and use information and samples you have already provided, and to continue to access information in administrative or medical databases (e.g., the Ontario Cancer Registry) and your personal medical records if you consented to this at the time you enrolled.

2. No further access: The Ontario Health Study will no longer contact you or ask you to participate in ongoing Study activities, and will not collect any further information about you from administrative and medical databases (e.g., the Ontario Cancer Registry) or your personal medical records, but will still have permission to keep and use information and samples you have already provided.

3. No further use: The Ontario Health Study will no longer contact you or ask you to participate in ongoing Study activities or collect additional information about you. Any information or samples you have already provided will be removed from our databases, your data will be unavailable to researchers, and you will not be able to access your physical measures or blood analysis reports on your personal home page. However, it is not possible to take back information or samples that have already been provided to researchers for analyses. Your signed consent and withdrawal will be kept as a record of your wishes.