The START trial: a proof-of-concept sedentary reduction program for prefrail older adults

PROJECT SUMMARY Frailty is a syndromic state of vulnerability that puts adults aged ≥65-years at heightened risk of adverse health outcomes. An estimated 50% of older Americans are prefrail—a pre-clinical stage of frailty that might be more amenable to intervention efforts than frailty. Increasing physical activity is a promising intervention to better

manage/help reverse the multisystem dysregulation that drives frailty and sequalae. However, initiating and maintaining habitual physical activity is difficult for sedentary older adults, particularly those encumbered by health challenges. The 2018 US Physical Activity Guidelines recommends that all adults perform ≥150

minutes/week of physical activity and reduce sedentary behaviors. Yet, traditional approaches to increase physical activity do little to address sedentary behavior reduction, especially for older adults. Lower sedentary behavior is associated with improved biological and psychosocial health—independent of meeting physical

activity guidelines. Thus, there remains a critical need to implement and evaluate a structured way to reduce sedentary behavior as a potential pathway for habitual physical activity engagement. Using novel objectively measured physical activity metrics, our research group has shown that daily sedentary time, either in total or

accrued in a prolonged manner, is associated with frailty. Our observation evidence shows that: 1) daily, non- exercise physical activity declines and becomes more fragmented with age (less continuous activity with longer sedentary bouts), 2) higher daily sedentary time and activity fragmentation are both associated with higher

frailty incidence, and 3) sedentary time is positively associated with frailty-related markers of inflammation. We propose a pilot study in which we randomize 60 prefrail community-dwelling older adults to receive one of two interventions, each designed to gradually reduce sedentary time: 1) continuously to form a 30-minute walking

bout, or 2) in a bouted manner to form three 10-minute walking bouts. Project goals are to: a) explore the effectiveness within and between interventions to decrease objectively measured sedentary time over 2 months; b) assess decreased sedentary time’s association with i) patient-reported outcomes and ii) frailty-

related inflammatory markers. The primary outcome is accelerometer-determined sedentary time. Secondary outcomes include activity fragmentation, patient-reported outcomes, and inflammatory markers. With a transdisciplinary mentoring panel, my career development plan builds on my expertise in aging and physical

activity epidemiology to gain proficiency in: 1) developing and implementing clinical trials for older adults, 2) designing interventions to improve health behaviors, 3) conducting frailty and inflammation related research and 4) gaining competencies to become an effective PI and leader. This project utilizes the infrastructure of the

Johns Hopkins Institute for Clinical and Translational Research (ICTR) and Beacham Center for Geriatric Medicine which have strong records of supporting early-stage faculty. This award will facilitate my transition to an independent investigator and will also provide informative data for R21 and R01 applications.