Cohort profile: baseline characteristics and design of the McMaster Monitoring My Mobility (MacM3) study – a prospective digital mobility cohort of community-dwelling older Canadians from Southern Ontario

PURPOSE: The McMaster Monitoring My Mobility (MacM3) study aims to understand trajectories of mobility decline in later life using multisensor wearable technology. To our knowledge, MacM3 is the first major cohort to combine accelerometry and a Global Positioning System (GPS) to track real-world mobility in community-dwelling older adults. PARTICIPANTS: Between May 2022 and May 2024, MacM3 recruited 1555 community-dwelling older adults (mean age 73.9 years, SD=5.5) from Hamilton and Toronto, Ontario. Of the cohort, 68.4% were female, 62.4% married/partnered, 75.3% had post-secondary education and 62.9% had≥3 comorbidities. Most were Canadian born (69.4%) and white/Caucasian (88.0%), with greater ethnocultural diversity observed at the Toronto site. FINDINGS TO DATE: At baseline, 56.7% of participants reported no mobility limitations, 15.9% had preclinical limitations and 27.4% had minor mobility limitations. Mean gait speed for the total sample was 1.23 m/s, with a mean Timed Up and Go time of 9.4 s and a 5× sit-to-stand time of 13.0 s. A total of 1301 participants had valid wrist-worn device data, and 1008 participants who agreed to wear the thigh-worn device had valid data (≥7 days with ≥10 hours of wear per day). Step count data (n=1008) revealed a mean of 8437 steps per day (SD=2943), with 5073 steps in the lowest quartile and 12 303 steps in the highest. FUTURE PLANS: Ongoing work aims to develop predictive models of mobility decline by integrating wearable, clinical and environmental data. Pipeline enhancements will enable GPS/inertial measurement unit fusion to explore mobility-environment interactions and support ageing-in-place tools.