Project 460811

Understanding the factors that allow some individuals to age more successfully than others has important implications for health policy and Alzheimer's disease (AD) prevention and interventions. Modifiable lifestyle factors, including educational and occupational attainment, cognitive and social engagement, and physical activity, are associated with risk of AD. However, how these factors exert their protective effects remains poorly understood. For example, it is unknown whether/which lifestyle factors work directly by reducing brain-related disease accumulation (i.e., brain maintenance) or indirectly through compensatory strategies that help preserve cognition and function in the face of brain disease (i.e., cognitive reserve). This study will investigate multiple lifestyle factors in a single study/sample to determine which lifestyle factors are most effective and whether they act on the brain (brain maintenance) or on behavior (cognitive reserve) to influence cognitive change over time. One hundred older adult participants from Philadelphia will complete self-reported measures of various lifestyle factors, including level and quality of education, socioeconomic status, and social, cognitive, and physical activity levels at various points across the lifespan. Participants also will undergo brain (PET) imaging for in-vivo measurement of markers of brain disease (i.e., beta-amyloid plaques and neurofibrillary tangles) at the time of study enrollment. All participants will complete cognitive testing at baseline and at one- and two-year follow-up visits to evaluate change in cognition over time. Statistical methods including moderation and causal mediation will be used to answer the research questions. Findings will identify the lifestyle factors that should be considered for health policy and prevention strategies for people of all ages, and whether there are optimal time points when lifestyle factors may exert the most influence on cognitive aging.