Factors associated with longitudinal survey adherence and smartwatch usage among older adults in the electronic Framingham Heart Study

Sustaining long-term adherence to digital health protocols remains a major challenge, and factors influencing sustained use of digital devices among older adults are poorly understood. We identified sociodemographic, health-related, and technological factors associated with longitudinal adherence to smartphone-based surveys (32 weeks) and smartwatch usage (52 weeks) among 611 older adults (median age 74 years, 57% women) in the electronic Framingham Heart Study, using multivariable mixed-effects regressions and longitudinal K-means clustering. Younger age (≤ 75 years), iPhone use, and lower depressive symptom scores were associated with higher survey response rates, whereas higher education, better diet quality, and lower medication counts were associated with higher smartwatch usage among the 405 smartwatch users. Cluster analysis identified three trajectories for each outcome: consistently high adherence or usage (63% and 67%, respectively), initially high with progressive decline (12% and 15%), and low initial adherence or usage with rapid decline (25% and 18%). Cluster characteristics reinforced the regression findings. These results identify smartphone type, age, depressive symptoms, education, diet quality, and medication use as key factors associated with digital health adherence among older adults, and they inform tailored strategies to promote sustained participation, particularly among older participants and those with greater health burdens.