Introduction
Statistics Canada began conducting the Canadian Health Measures Survey (CHMS) in 2007. Ongoing data collection continues in two year cycles. This survey collects direct physical measures of Canadians' health including blood and urine samples for laboratory testing. For each two-year collection period, about 5,500 participants among the ages of 3 to 79 complete the physical measures testing in the CHMS mobile examination centre that travels to sites across the country. Participation in all components of the survey is voluntary for the selected participants.
Additionally, all components of this national survey are reviewed and authorized annually by the Health Canada/Public Health Agency of Canada Research Ethics Board (REB# 2005-0025).
Objectives
The extensive privacy impact assessment for the CHMS is reviewed and updated for changes at the beginning of each new collection period. These updates are designed to identify new privacy, confidentiality and security risks to participants' personal information, to make recommendations to resolve or mitigate these risks, and to report on ongoing or previously identified concerns.
Description
The CHMS collects information to inform policy makers, health professionals and researchers on Canadian health status such as exposure to environmental contaminants and infectious disease, lifestyle characteristics (e.g., physical activity levels and nutritional status) and the extent of chronic diseases (e.g. heart and lung health). The survey also provides the infrastructure to explore new measurement technologies and emerging public health issues in Canada.
The CHMS collects contextual health—and safety screening—information through a questionnaire administered in the household. Later, at the mobile examination centre, participants undergo a series of physical measure tests and are asked to provide blood and urine samples that are sent to CHMS reference labs for testing. A small portion of the samples (blood, urine, DNA) may be stored for use in additional health studies from participants who agree to this use of their samples.
Privacy risks and mitigation measures
Because of the highly personal nature of the information being collected, tested and processed, the ongoing privacy impact assessment identifies several privacy issues and risks that are communicated and discussed with CHMS participants. This permits respondents to make an informed decision on whether to participate in the survey including the following:
- Consent to specific uses of the information participants provide (linking, sharing, storage)
- Reporting back survey and laboratory results to respondents
- Transmission of information/samples between the mobile examination centre, laboratories and Statistics Canada.
Measures put in place to address these issues include providing comprehensive information to obtain separate written informed consents—at the time of first collection—from respondents to participate in the survey, sample storage (blood and urine), DNA storage and infectious disease testing. Nine times throughout the 3 to 4 hour collection period participants are asked to direct Statistics Canada in the way their information may be used or for their wishes on restriction to use.
CHMS Biobank
Concerns raised by the federal privacy commissioner's office during previous reviews centred on the uncertainty of the CHMS biobank and the storage of blood, urine and DNA for use in future health studies, including the following issues:
- Retention of personal identifiers
- Storage of physical specimens (blood, urine and DNA) and destruction
- Permission of respondents for future tests
- Governance and criteria for use of stored specimens in future health studies
- Informing participants about additional studies and methods to withdraw consent
- Consent to stored specimens regarding children in the survey
Governance of the Biobank is now determined as are procedures for access and use of the stored specimens. Measures put in place to address previous concerns include enhanced security for specimens, with barcode labelling, in the National Microbiology Laboratory in Winnipeg. Laboratories authorized to conduct additional study analyses are secured and authorized under contract to monitor specimen use through to destruction, and all lab results are returned to Statistics Canada for processing and data creation. Researchers using these data must become deemed employees of Statistics Canada which entails a security check, a conflict of interest declaration, and a sworn oath that they understand and accept the responsibility that disclosure of any personal information is a criminal offence.
Additionally, the procedures surrounding access and use of the CHMS stored samples have been vetted through extensive consultations and tested in two pilot studies approved through independent scientific and ethical reviews. The (a) governance of the Biobank, (b) criteria for use of stored specimens, and (c) ongoing rights of participants to find out how their samples are being used and to withdraw their samples at any time form the backbone measures that Statistics Canada has put in place to respond to privacy concerns about the CHMS biobank. Details of these measures are available at www.statcan.gc.ca/chms under the biobank section.
Conclusion
With the enhanced and existing Statistics Canada safeguards and procedures, as well as those in place at the mobile clinics and the laboratories, any remaining risks will be either negligible or are such that Statistics Canada is prepared to accept and manage these risks.