PROJECT SUMMARY In 2020, an estimated 5.8 million Americans had Alzheimer’s disease (AD), the most common cause of dementia, and this number is expected to reach 13.8 million by 2050. Alzheimer’s Disease and related dementias (ADRD) take an enormous toll on individuals affected, as well as their caregivers. Because disease- modifying therapies have proved largely ineffective, a priority is placed on finding ways to prevent this debilitating disease. This is particularly important for Black Americans who have a greater risk for poor cognitive aging compared to non-Hispanic White Americans, whether measured as clinical dementia or lower cognitive function in late life. Because neighborhood design factors can be modified at the population level through policy and regulation, they are an attractive area for intervention. Green space is one neighborhood design element that may be associated with cognitive function because exposure to it may reduce stress, improve mood, promote physical activity, and provide opportunities for social engagement, all of which have been associated with better cognitive health. Communities of color are more likely to live in neighborhoods with lower green space than white communities and structural racism, through past discriminatory policies leading to residential segregation, has been implicated in this inequitable distribution of green space. Recognition of these inequities has led to recent efforts to increase the amount and quality of green space in historically disadvantaged communities through park improvement projects, street tree plantings, and vacant lot restoration. While these initiatives may have the intention of combatting decades of disinvestment rooted in structural racism, they may, instead, end up reinforcing segregation by race and/or socioeconomic status because of gentrification, a process by which under-resourced neighborhoods are developed and experience in-migration of affluent newcomers. Therefore, it is unclear if green space improvements are harmful or beneficial to communities of color, particularly in neighborhoods that are undergoing revitalization. In the proposed work, we will (1) assess the cross-sectional and longitudinal association between changes in green space and cognitive function, cognitive decline, and dementia over a 20-year period in the (a) overall population and (b) by race/ethnicity; (2) estimate the association between structural racism (as measured by historical redlining spatial patterns) and cognitive function, cognitive decline, and dementia; and determine if this association is mediated by green space exposure; (3) determine if (a) the association between green space and cognitive function, cognitive decline, and dementia is moderated by gentrification; and (b) there is an independent association between gentrification and psychosocial stressors, mental health, and perceived neighborhood characteristics; and (4) partner with a national network of local environmental justice-oriented organizations to explore barriers and facilitators to green space improvements and mitigation for displacement due to gentrification. This work has the potential to provide guidance to improve cognitive health equity.

PROJECT NARRATIVE Alzheimer’s Disease and related dementias (ADRD) take an enormous toll on public health and are more prevalent in Black Americans than White Americans. Structural racism, and its lasting effect on the distribution of neighborhood factors, such as green space, may play a role in cognitive health disparities. The proposed project will investigate the relationships between structural racism, green space exposure, and cognitive health disparities, as well as whether these relationships differ in communities that have undergone gentrification compared to those that have not.