Facilitators and Barriers to Adherence and Engagement in a Lifestyle Intervention for High-Risk Older Adults: A Multi-Trial Analysis

<b>Background</b>: High adherence and engagement are critical components of successful lifestyle interventions for health outcomes. Gaps persist in understanding the multifaceted factors influencing older participants' ability to adhere and engage with health behavior interventions. <b>Methods</b>: Using data from two pilot randomized clinical trials evaluating a nutrition program in older adults at increased risk for dementia, we evaluated participant-level factors influencing adherence and engagement with the recommended diet and program. Additional qualitative themes were used to provide context. Both trials are registered on ClinicalTrials.gov (Pilot A: NCT0417176 on 23 March 2021 and Pilot B: NCT06121986 on 30 October 2023). <b>Results</b>: Better income, cognitive functioning, emotion regulation, quality of life, and independence in activities of daily living were associated with better dietary adherence, while being non-White, living in a rural area, having higher depressive symptoms, worse health symptoms, and worse sleep quality were negatively associated with adherence. Higher education, cognitive function, anxiety, and previous weight challenges were associated with better program engagement. <b>Conclusions</b>: Adherence and engagement were impacted by a combination of individual factors, including cognition, mood, physical health, as well as the broader socioeconomic context. Our findings highlight the ways psychological and social determinants of health may impact adherence to lifestyle interventions.