The Canadian platform for research online to investigate health, quality of life, cognition, behaviour, function, and caregiving in aging (CAN-PROTECT): Study protocol, platform description, and preliminary analyses

• CAN-PROTECT is a longitudinal online study of risk and resilience to brain aging. • Neuropsychological testing and health- and aging-related outcomes are obtained. • Data presented are from the first 2150 participants, mean age 62.9 (77.6 % female). • Associations between cognition, behaviour, function, and quality of life were found. • CAN-PROTECT is a feasible platform to obtain participant and study partner data. : Preventing or reducing the risk of cognitive decline and dementia is of great public health interest. Longitudinal data from diverse samples are needed to properly inform clinicians, researchers, and policy makers. CAN-PROTECT is a recently launched online observational cohort study that assesses factors contributing to both risk for incident cognitive decline and dementia and resilience against brain aging, in participants across the lifespan. : Measures of cognition, behaviour, and quality of life administered to both participants and study partners were compared using partial Spearman correlations adjusted for participant and study partner age, sex, and education. In participants, relationships between cognition, behaviour, function, and quality of life were examined using adjusted multivariable linear and negative binomial regression models. : In the first three-month window, 2150 participants spanning all Canadian provinces enrolled; 637 nominated study partners had already completed assessments. Engagement with the study was excellent, with many optional assessments completed. Initial analyses demonstrated relationships between cognition, behaviour, function, and quality of life. : These preliminary results speak to the utility and feasibility of CAN-PROTECT to obtain data relevant to brain health, highlighting the public interest in participating in studies on cognition. The online portal facilitated participation of a geographically diverse sample. This group is ideal to study brain aging, dementia prevention, and early detection of neurodegenerative disease. Longitudinal data will provide additional insights. Several features of CAN-PROTECT are important to consider in terms of assessing risk and resilience in Canadians, and for further development and recruitment of a research-ready cohort.