Environmental Influences and Gene–Environment Interplay in Cognitive Aging: Access to Parks and Trails

Environments that facilitate physical activity and cognitive engagement may support cognitive functioning and reduce cognitive aging (Besser et al., 2021; Cassarino & Setti, 2015; Finlay et al., 2022). Green space features have been theorized to support cognitive function in at least two ways, i.e., directly via engagement of perceptual processes and indirectly through physical activity engagement (Cassarino & Setti, 2015). Understanding whether and how accessibility to green space, particularly parks and trails, is associated with cognitive function is critical to identifying modifiable factors that support healthy cognitive trajectories. Few studies have linked green space to cognitive outcomes prior to midlife, and fewer yet have investigated how these pathways interact with individual differences in genetics and neighborhood level attributes. Integrating these data provide a novel opportunity to assess how the lived environment contributes to cognitive aging through perceptual and biological pathways; therefore, the aims for this project are: Aim 1: Examine whether access to parks and trails is associated with cognitive performance and investigate if this relationship is moderated by age. Aim 2: Evaluate whether genetic factors, such as APOE status or polygenic risk for Alzheimer’s disease (AD-PGS) moderate these associations. Together, these aims will clarify the pathways of association between parks and trails and cognitive functioning prior to midlife and identify accessible community-level targets for prevention and intervention. Analyses will enter sociodemographic variables at the neighborhood and individual level as covariates (e.g., neighborhood SVI theme 1, perceptions of safety and crime (c.f., Munoz et al., 2020) and educational and occupational attainment), as well as pollution measures (Smolker et al., 2024). Follow-up analyses of Aim 1 will evaluate park definitions and specific park features to further probe the affordances of green space and associations with cognition, i.e., recreation grounds versus parks, nature reserves, meadows and forests. In addition, we will compare park and trail sources to evaluate replicability with recent work (e.g., compare OSM to NaNDA; c.f. Finlay et al., 2022). Access to parks and trails (indexed by the number within 1 mile and distance to the nearest park) will be examined as an exogenous environmental construct predicting cognition both directly and indirectly with physical activity serving as a mediator of the relationship between environment and cognition. Genetic risk (APOE status and/or AD polygenic score) is examined as a moderator of the direct path from park and trail access to cognition and of the indirect path by moderating the association between physical activity and cognition, testing genetic moderation on both direct and mediated pathways to cognitive outcomes.